Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/kernel/printk.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | * |
| 6 | * Modified to make sys_syslog() more flexible: added commands to |
| 7 | * return the last 4k of kernel messages, regardless of whether |
| 8 | * they've been read or not. Added option to suppress kernel printk's |
| 9 | * to the console. Added hook for sending the console messages |
| 10 | * elsewhere, in preparation for a serial line console (someday). |
| 11 | * Ted Ts'o, 2/11/93. |
| 12 | * Modified for sysctl support, 1/8/97, Chris Horn. |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 13 | * Fixed SMP synchronization, 08/08/99, Manfred Spraul |
Christian Kujau | 624dffc | 2006-01-15 02:43:54 +0100 | [diff] [blame] | 14 | * manfred@colorfullife.com |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | * Rewrote bits to get rid of console_lock |
Francois Cami | e1f8e87 | 2008-10-15 22:01:59 -0700 | [diff] [blame] | 16 | * 01Mar01 Andrew Morton |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | */ |
| 18 | |
| 19 | #include <linux/kernel.h> |
| 20 | #include <linux/mm.h> |
| 21 | #include <linux/tty.h> |
| 22 | #include <linux/tty_driver.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | #include <linux/console.h> |
| 24 | #include <linux/init.h> |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 25 | #include <linux/jiffies.h> |
| 26 | #include <linux/nmi.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <linux/module.h> |
Jan Engelhardt | 3b9c041 | 2006-06-25 05:48:15 -0700 | [diff] [blame] | 28 | #include <linux/moduleparam.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/interrupt.h> /* For in_interrupt() */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | #include <linux/delay.h> |
| 31 | #include <linux/smp.h> |
| 32 | #include <linux/security.h> |
| 33 | #include <linux/bootmem.h> |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 34 | #include <linux/memblock.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #include <linux/syscalls.h> |
Neil Horman | 04d491a | 2009-04-02 16:58:57 -0700 | [diff] [blame] | 36 | #include <linux/kexec.h> |
Jason Wessel | d37d39a | 2010-05-20 21:04:27 -0500 | [diff] [blame] | 37 | #include <linux/kdb.h> |
Ingo Molnar | 3fff4c4 | 2009-09-22 16:18:09 +0200 | [diff] [blame] | 38 | #include <linux/ratelimit.h> |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 39 | #include <linux/kmsg_dump.h> |
Kees Cook | 0023459 | 2010-02-03 15:36:43 -0800 | [diff] [blame] | 40 | #include <linux/syslog.h> |
Kevin Cernekee | 034260d | 2010-06-03 22:11:25 -0700 | [diff] [blame] | 41 | #include <linux/cpu.h> |
| 42 | #include <linux/notifier.h> |
Huang Ying | fb842b0 | 2011-01-12 16:59:43 -0800 | [diff] [blame] | 43 | #include <linux/rculist.h> |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 44 | #include <linux/poll.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | |
| 46 | #include <asm/uaccess.h> |
| 47 | |
Johannes Berg | 9510035 | 2011-11-24 20:03:08 +0100 | [diff] [blame] | 48 | #define CREATE_TRACE_POINTS |
| 49 | #include <trace/events/printk.h> |
| 50 | |
Ingo Molnar | 076f977 | 2008-01-30 13:33:06 +0100 | [diff] [blame] | 51 | /* |
| 52 | * Architectures can override it: |
| 53 | */ |
Jiri Slaby | e17ba73 | 2008-05-12 15:44:40 +0200 | [diff] [blame] | 54 | void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...) |
Ingo Molnar | 076f977 | 2008-01-30 13:33:06 +0100 | [diff] [blame] | 55 | { |
| 56 | } |
| 57 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | /* printk's without a loglevel use this.. */ |
Mandeep Singh Baines | 5af5bcb | 2011-03-22 16:34:23 -0700 | [diff] [blame] | 59 | #define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | |
| 61 | /* We show everything that is MORE important than this.. */ |
| 62 | #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */ |
| 63 | #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */ |
| 64 | |
| 65 | DECLARE_WAIT_QUEUE_HEAD(log_wait); |
| 66 | |
| 67 | int console_printk[4] = { |
| 68 | DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */ |
| 69 | DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */ |
| 70 | MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */ |
| 71 | DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ |
| 72 | }; |
| 73 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | /* |
Patrick Pletscher | 0bbfb7c | 2007-02-17 20:10:16 +0100 | [diff] [blame] | 75 | * Low level drivers may need that to know if they can schedule in |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | * their unblank() callback or not. So let's export it. |
| 77 | */ |
| 78 | int oops_in_progress; |
| 79 | EXPORT_SYMBOL(oops_in_progress); |
| 80 | |
| 81 | /* |
| 82 | * console_sem protects the console_drivers list, and also |
| 83 | * provides serialisation for access to the entire console |
| 84 | * driver system. |
| 85 | */ |
Thomas Gleixner | 5b8c4f2 | 2010-09-07 14:33:43 +0000 | [diff] [blame] | 86 | static DEFINE_SEMAPHORE(console_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | struct console *console_drivers; |
Ingo Molnar | a29d1cf | 2008-06-02 13:19:08 +0200 | [diff] [blame] | 88 | EXPORT_SYMBOL_GPL(console_drivers); |
| 89 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | /* |
| 91 | * This is used for debugging the mess that is the VT code by |
| 92 | * keeping track if we have the console semaphore held. It's |
| 93 | * definitely not the perfect debug tool (we don't know if _WE_ |
| 94 | * hold it are racing, but it helps tracking those weird code |
| 95 | * path in the console code where we end up in places I want |
| 96 | * locked without the console sempahore held |
| 97 | */ |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 98 | static int console_locked, console_suspended; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | |
| 100 | /* |
Feng Tang | fe3d8ad | 2011-03-22 16:34:21 -0700 | [diff] [blame] | 101 | * If exclusive_console is non-NULL then only this console is to be printed to. |
| 102 | */ |
| 103 | static struct console *exclusive_console; |
| 104 | |
| 105 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | * Array of consoles built from command line options (console=) |
| 107 | */ |
| 108 | struct console_cmdline |
| 109 | { |
| 110 | char name[8]; /* Name of the driver */ |
| 111 | int index; /* Minor dev. to use */ |
| 112 | char *options; /* Options for the driver */ |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 113 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 114 | char *brl_options; /* Options for braille driver */ |
| 115 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 116 | }; |
| 117 | |
| 118 | #define MAX_CMDLINECONSOLES 8 |
| 119 | |
| 120 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; |
| 121 | static int selected_console = -1; |
| 122 | static int preferred_console = -1; |
Markus Armbruster | 9e124fe | 2008-05-26 23:31:07 +0100 | [diff] [blame] | 123 | int console_set_on_cmdline; |
| 124 | EXPORT_SYMBOL(console_set_on_cmdline); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | |
| 126 | /* Flag: console code may call schedule() */ |
| 127 | static int console_may_schedule; |
| 128 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 129 | /* |
| 130 | * The printk log buffer consists of a chain of concatenated variable |
| 131 | * length records. Every record starts with a record header, containing |
| 132 | * the overall length of the record. |
| 133 | * |
| 134 | * The heads to the first and last entry in the buffer, as well as the |
| 135 | * sequence numbers of these both entries are maintained when messages |
| 136 | * are stored.. |
| 137 | * |
| 138 | * If the heads indicate available messages, the length in the header |
| 139 | * tells the start next message. A length == 0 for the next message |
| 140 | * indicates a wrap-around to the beginning of the buffer. |
| 141 | * |
| 142 | * Every record carries the monotonic timestamp in microseconds, as well as |
| 143 | * the standard userspace syslog level and syslog facility. The usual |
| 144 | * kernel messages use LOG_KERN; userspace-injected messages always carry |
| 145 | * a matching syslog facility, by default LOG_USER. The origin of every |
| 146 | * message can be reliably determined that way. |
| 147 | * |
| 148 | * The human readable log message directly follows the message header. The |
| 149 | * length of the message text is stored in the header, the stored message |
| 150 | * is not terminated. |
| 151 | * |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 152 | * Optionally, a message can carry a dictionary of properties (key/value pairs), |
| 153 | * to provide userspace with a machine-readable message context. |
| 154 | * |
| 155 | * Examples for well-defined, commonly used property names are: |
| 156 | * DEVICE=b12:8 device identifier |
| 157 | * b12:8 block dev_t |
| 158 | * c127:3 char dev_t |
| 159 | * n8 netdev ifindex |
| 160 | * +sound:card0 subsystem:devname |
| 161 | * SUBSYSTEM=pci driver-core subsystem name |
| 162 | * |
| 163 | * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value |
| 164 | * follows directly after a '=' character. Every property is terminated by |
| 165 | * a '\0' character. The last property is not terminated. |
| 166 | * |
| 167 | * Example of a message structure: |
| 168 | * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec |
| 169 | * 0008 34 00 record is 52 bytes long |
| 170 | * 000a 0b 00 text is 11 bytes long |
| 171 | * 000c 1f 00 dictionary is 23 bytes long |
| 172 | * 000e 03 00 LOG_KERN (facility) LOG_ERR (level) |
| 173 | * 0010 69 74 27 73 20 61 20 6c "it's a l" |
| 174 | * 69 6e 65 "ine" |
| 175 | * 001b 44 45 56 49 43 "DEVIC" |
| 176 | * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D" |
| 177 | * 52 49 56 45 52 3d 62 75 "RIVER=bu" |
| 178 | * 67 "g" |
| 179 | * 0032 00 00 00 padding to next message header |
| 180 | * |
| 181 | * The 'struct log' buffer header must never be directly exported to |
| 182 | * userspace, it is a kernel-private implementation detail that might |
| 183 | * need to be changed in the future, when the requirements change. |
| 184 | * |
| 185 | * /dev/kmsg exports the structured data in the following line format: |
| 186 | * "level,sequnum,timestamp;<message text>\n" |
| 187 | * |
| 188 | * The optional key/value pairs are attached as continuation lines starting |
| 189 | * with a space character and terminated by a newline. All possible |
| 190 | * non-prinatable characters are escaped in the "\xff" notation. |
| 191 | * |
| 192 | * Users of the export format should ignore possible additional values |
| 193 | * separated by ',', and find the message after the ';' character. |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 194 | */ |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 195 | |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 196 | enum log_flags { |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 197 | LOG_NOCONS = 1, /* already flushed, do not print to console */ |
| 198 | LOG_NEWLINE = 2, /* text ended with a newline */ |
| 199 | LOG_PREFIX = 4, /* text started with a prefix */ |
| 200 | LOG_CONT = 8, /* text is a fragment of a continuation line */ |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 201 | }; |
| 202 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 203 | struct log { |
| 204 | u64 ts_nsec; /* timestamp in nanoseconds */ |
| 205 | u16 len; /* length of entire record */ |
| 206 | u16 text_len; /* length of text buffer */ |
| 207 | u16 dict_len; /* length of dictionary buffer */ |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 208 | u8 facility; /* syslog facility */ |
| 209 | u8 flags:5; /* internal record flags */ |
| 210 | u8 level:3; /* syslog level */ |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 211 | }; |
| 212 | |
| 213 | /* |
| 214 | * The logbuf_lock protects kmsg buffer, indices, counters. It is also |
| 215 | * used in interesting ways to provide interlocking in console_unlock(); |
| 216 | */ |
| 217 | static DEFINE_RAW_SPINLOCK(logbuf_lock); |
| 218 | |
Kay Sievers | 7f3a781 | 2012-05-09 01:37:51 +0200 | [diff] [blame] | 219 | /* the next printk record to read by syslog(READ) or /proc/kmsg */ |
| 220 | static u64 syslog_seq; |
| 221 | static u32 syslog_idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 222 | static enum log_flags syslog_prev; |
Kay Sievers | eb02dac | 2012-07-09 10:05:10 -0700 | [diff] [blame] | 223 | static size_t syslog_partial; |
Kay Sievers | 7f3a781 | 2012-05-09 01:37:51 +0200 | [diff] [blame] | 224 | |
| 225 | /* index and sequence number of the first record stored in the buffer */ |
| 226 | static u64 log_first_seq; |
| 227 | static u32 log_first_idx; |
| 228 | |
| 229 | /* index and sequence number of the next record to store in the buffer */ |
| 230 | static u64 log_next_seq; |
| 231 | #ifdef CONFIG_PRINTK |
| 232 | static u32 log_next_idx; |
| 233 | |
| 234 | /* the next printk record to read after the last 'clear' command */ |
| 235 | static u64 clear_seq; |
| 236 | static u32 clear_idx; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 237 | |
| 238 | #define LOG_LINE_MAX 1024 |
| 239 | |
| 240 | /* record buffer */ |
Andrew Lunn | 6ebb017 | 2012-06-05 08:52:34 +0200 | [diff] [blame] | 241 | #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) |
Stephen Warren | f8450fc | 2012-05-10 16:14:33 -0600 | [diff] [blame] | 242 | #define LOG_ALIGN 4 |
| 243 | #else |
Andrew Lunn | 6ebb017 | 2012-06-05 08:52:34 +0200 | [diff] [blame] | 244 | #define LOG_ALIGN __alignof__(struct log) |
Stephen Warren | f8450fc | 2012-05-10 16:14:33 -0600 | [diff] [blame] | 245 | #endif |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 246 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
Stephen Warren | f8450fc | 2012-05-10 16:14:33 -0600 | [diff] [blame] | 247 | static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 248 | static char *log_buf = __log_buf; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 249 | static u32 log_buf_len = __LOG_BUF_LEN; |
| 250 | |
Kay Sievers | 7f3a781 | 2012-05-09 01:37:51 +0200 | [diff] [blame] | 251 | /* cpu currently holding logbuf_lock */ |
| 252 | static volatile unsigned int logbuf_cpu = UINT_MAX; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 253 | |
| 254 | /* human readable text of the record */ |
| 255 | static char *log_text(const struct log *msg) |
| 256 | { |
| 257 | return (char *)msg + sizeof(struct log); |
| 258 | } |
| 259 | |
| 260 | /* optional key/value pair dictionary attached to the record */ |
| 261 | static char *log_dict(const struct log *msg) |
| 262 | { |
| 263 | return (char *)msg + sizeof(struct log) + msg->text_len; |
| 264 | } |
| 265 | |
| 266 | /* get record by index; idx must point to valid msg */ |
| 267 | static struct log *log_from_idx(u32 idx) |
| 268 | { |
| 269 | struct log *msg = (struct log *)(log_buf + idx); |
| 270 | |
| 271 | /* |
| 272 | * A length == 0 record is the end of buffer marker. Wrap around and |
| 273 | * read the message at the start of the buffer. |
| 274 | */ |
| 275 | if (!msg->len) |
| 276 | return (struct log *)log_buf; |
| 277 | return msg; |
| 278 | } |
| 279 | |
| 280 | /* get next record; idx must point to valid msg */ |
| 281 | static u32 log_next(u32 idx) |
| 282 | { |
| 283 | struct log *msg = (struct log *)(log_buf + idx); |
| 284 | |
| 285 | /* length == 0 indicates the end of the buffer; wrap */ |
| 286 | /* |
| 287 | * A length == 0 record is the end of buffer marker. Wrap around and |
| 288 | * read the message at the start of the buffer as *this* one, and |
| 289 | * return the one after that. |
| 290 | */ |
| 291 | if (!msg->len) { |
| 292 | msg = (struct log *)log_buf; |
| 293 | return msg->len; |
| 294 | } |
| 295 | return idx + msg->len; |
| 296 | } |
| 297 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 298 | /* insert record into the buffer, discard old ones, update heads */ |
| 299 | static void log_store(int facility, int level, |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 300 | enum log_flags flags, u64 ts_nsec, |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 301 | const char *dict, u16 dict_len, |
| 302 | const char *text, u16 text_len) |
| 303 | { |
| 304 | struct log *msg; |
| 305 | u32 size, pad_len; |
| 306 | |
| 307 | /* number of '\0' padding bytes to next message */ |
| 308 | size = sizeof(struct log) + text_len + dict_len; |
| 309 | pad_len = (-size) & (LOG_ALIGN - 1); |
| 310 | size += pad_len; |
| 311 | |
| 312 | while (log_first_seq < log_next_seq) { |
| 313 | u32 free; |
| 314 | |
| 315 | if (log_next_idx > log_first_idx) |
| 316 | free = max(log_buf_len - log_next_idx, log_first_idx); |
| 317 | else |
| 318 | free = log_first_idx - log_next_idx; |
| 319 | |
| 320 | if (free > size + sizeof(struct log)) |
| 321 | break; |
| 322 | |
| 323 | /* drop old messages until we have enough contiuous space */ |
| 324 | log_first_idx = log_next(log_first_idx); |
| 325 | log_first_seq++; |
| 326 | } |
| 327 | |
| 328 | if (log_next_idx + size + sizeof(struct log) >= log_buf_len) { |
| 329 | /* |
| 330 | * This message + an additional empty header does not fit |
| 331 | * at the end of the buffer. Add an empty header with len == 0 |
| 332 | * to signify a wrap around. |
| 333 | */ |
| 334 | memset(log_buf + log_next_idx, 0, sizeof(struct log)); |
| 335 | log_next_idx = 0; |
| 336 | } |
| 337 | |
| 338 | /* fill message */ |
| 339 | msg = (struct log *)(log_buf + log_next_idx); |
| 340 | memcpy(log_text(msg), text, text_len); |
| 341 | msg->text_len = text_len; |
| 342 | memcpy(log_dict(msg), dict, dict_len); |
| 343 | msg->dict_len = dict_len; |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 344 | msg->facility = facility; |
| 345 | msg->level = level & 7; |
| 346 | msg->flags = flags & 0x1f; |
| 347 | if (ts_nsec > 0) |
| 348 | msg->ts_nsec = ts_nsec; |
| 349 | else |
| 350 | msg->ts_nsec = local_clock(); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 351 | memset(log_dict(msg) + dict_len, 0, pad_len); |
| 352 | msg->len = sizeof(struct log) + text_len + dict_len + pad_len; |
| 353 | |
| 354 | /* insert message */ |
| 355 | log_next_idx += msg->len; |
| 356 | log_next_seq++; |
| 357 | } |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 358 | |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 359 | /* /dev/kmsg - userspace message inject/listen interface */ |
| 360 | struct devkmsg_user { |
| 361 | u64 seq; |
| 362 | u32 idx; |
| 363 | struct mutex lock; |
| 364 | char buf[8192]; |
| 365 | }; |
| 366 | |
| 367 | static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv, |
| 368 | unsigned long count, loff_t pos) |
| 369 | { |
| 370 | char *buf, *line; |
| 371 | int i; |
| 372 | int level = default_message_loglevel; |
| 373 | int facility = 1; /* LOG_USER */ |
| 374 | size_t len = iov_length(iv, count); |
| 375 | ssize_t ret = len; |
| 376 | |
| 377 | if (len > LOG_LINE_MAX) |
| 378 | return -EINVAL; |
| 379 | buf = kmalloc(len+1, GFP_KERNEL); |
| 380 | if (buf == NULL) |
| 381 | return -ENOMEM; |
| 382 | |
| 383 | line = buf; |
| 384 | for (i = 0; i < count; i++) { |
| 385 | if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) |
| 386 | goto out; |
| 387 | line += iv[i].iov_len; |
| 388 | } |
| 389 | |
| 390 | /* |
| 391 | * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace |
| 392 | * the decimal value represents 32bit, the lower 3 bit are the log |
| 393 | * level, the rest are the log facility. |
| 394 | * |
| 395 | * If no prefix or no userspace facility is specified, we |
| 396 | * enforce LOG_USER, to be able to reliably distinguish |
| 397 | * kernel-generated messages from userspace-injected ones. |
| 398 | */ |
| 399 | line = buf; |
| 400 | if (line[0] == '<') { |
| 401 | char *endp = NULL; |
| 402 | |
| 403 | i = simple_strtoul(line+1, &endp, 10); |
| 404 | if (endp && endp[0] == '>') { |
| 405 | level = i & 7; |
| 406 | if (i >> 3) |
| 407 | facility = i >> 3; |
| 408 | endp++; |
| 409 | len -= endp - line; |
| 410 | line = endp; |
| 411 | } |
| 412 | } |
| 413 | line[len] = '\0'; |
| 414 | |
| 415 | printk_emit(facility, level, NULL, 0, "%s", line); |
| 416 | out: |
| 417 | kfree(buf); |
| 418 | return ret; |
| 419 | } |
| 420 | |
| 421 | static ssize_t devkmsg_read(struct file *file, char __user *buf, |
| 422 | size_t count, loff_t *ppos) |
| 423 | { |
| 424 | struct devkmsg_user *user = file->private_data; |
| 425 | struct log *msg; |
Kay Sievers | 5fc32490 | 2012-05-08 13:04:17 +0200 | [diff] [blame] | 426 | u64 ts_usec; |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 427 | size_t i; |
| 428 | size_t len; |
| 429 | ssize_t ret; |
| 430 | |
| 431 | if (!user) |
| 432 | return -EBADF; |
| 433 | |
Yuanhan Liu | 4a77a5a | 2012-06-16 21:21:51 +0800 | [diff] [blame] | 434 | ret = mutex_lock_interruptible(&user->lock); |
| 435 | if (ret) |
| 436 | return ret; |
liu chuansheng | 5c53d81 | 2012-07-06 09:50:08 -0700 | [diff] [blame] | 437 | raw_spin_lock_irq(&logbuf_lock); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 438 | while (user->seq == log_next_seq) { |
| 439 | if (file->f_flags & O_NONBLOCK) { |
| 440 | ret = -EAGAIN; |
liu chuansheng | 5c53d81 | 2012-07-06 09:50:08 -0700 | [diff] [blame] | 441 | raw_spin_unlock_irq(&logbuf_lock); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 442 | goto out; |
| 443 | } |
| 444 | |
liu chuansheng | 5c53d81 | 2012-07-06 09:50:08 -0700 | [diff] [blame] | 445 | raw_spin_unlock_irq(&logbuf_lock); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 446 | ret = wait_event_interruptible(log_wait, |
| 447 | user->seq != log_next_seq); |
| 448 | if (ret) |
| 449 | goto out; |
liu chuansheng | 5c53d81 | 2012-07-06 09:50:08 -0700 | [diff] [blame] | 450 | raw_spin_lock_irq(&logbuf_lock); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 451 | } |
| 452 | |
| 453 | if (user->seq < log_first_seq) { |
| 454 | /* our last seen message is gone, return error and reset */ |
| 455 | user->idx = log_first_idx; |
| 456 | user->seq = log_first_seq; |
| 457 | ret = -EPIPE; |
liu chuansheng | 5c53d81 | 2012-07-06 09:50:08 -0700 | [diff] [blame] | 458 | raw_spin_unlock_irq(&logbuf_lock); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 459 | goto out; |
| 460 | } |
| 461 | |
| 462 | msg = log_from_idx(user->idx); |
Kay Sievers | 5fc32490 | 2012-05-08 13:04:17 +0200 | [diff] [blame] | 463 | ts_usec = msg->ts_nsec; |
| 464 | do_div(ts_usec, 1000); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 465 | len = sprintf(user->buf, "%u,%llu,%llu;", |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 466 | (msg->facility << 3) | msg->level, user->seq, ts_usec); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 467 | |
| 468 | /* escape non-printable characters */ |
| 469 | for (i = 0; i < msg->text_len; i++) { |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 470 | unsigned char c = log_text(msg)[i]; |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 471 | |
Kay Sievers | e3f5a5f | 2012-07-06 09:50:09 -0700 | [diff] [blame] | 472 | if (c < ' ' || c >= 127 || c == '\\') |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 473 | len += sprintf(user->buf + len, "\\x%02x", c); |
| 474 | else |
| 475 | user->buf[len++] = c; |
| 476 | } |
| 477 | user->buf[len++] = '\n'; |
| 478 | |
| 479 | if (msg->dict_len) { |
| 480 | bool line = true; |
| 481 | |
| 482 | for (i = 0; i < msg->dict_len; i++) { |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 483 | unsigned char c = log_dict(msg)[i]; |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 484 | |
| 485 | if (line) { |
| 486 | user->buf[len++] = ' '; |
| 487 | line = false; |
| 488 | } |
| 489 | |
| 490 | if (c == '\0') { |
| 491 | user->buf[len++] = '\n'; |
| 492 | line = true; |
| 493 | continue; |
| 494 | } |
| 495 | |
Kay Sievers | e3f5a5f | 2012-07-06 09:50:09 -0700 | [diff] [blame] | 496 | if (c < ' ' || c >= 127 || c == '\\') { |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 497 | len += sprintf(user->buf + len, "\\x%02x", c); |
| 498 | continue; |
| 499 | } |
| 500 | |
| 501 | user->buf[len++] = c; |
| 502 | } |
| 503 | user->buf[len++] = '\n'; |
| 504 | } |
| 505 | |
| 506 | user->idx = log_next(user->idx); |
| 507 | user->seq++; |
liu chuansheng | 5c53d81 | 2012-07-06 09:50:08 -0700 | [diff] [blame] | 508 | raw_spin_unlock_irq(&logbuf_lock); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 509 | |
| 510 | if (len > count) { |
| 511 | ret = -EINVAL; |
| 512 | goto out; |
| 513 | } |
| 514 | |
| 515 | if (copy_to_user(buf, user->buf, len)) { |
| 516 | ret = -EFAULT; |
| 517 | goto out; |
| 518 | } |
| 519 | ret = len; |
| 520 | out: |
| 521 | mutex_unlock(&user->lock); |
| 522 | return ret; |
| 523 | } |
| 524 | |
| 525 | static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) |
| 526 | { |
| 527 | struct devkmsg_user *user = file->private_data; |
| 528 | loff_t ret = 0; |
| 529 | |
| 530 | if (!user) |
| 531 | return -EBADF; |
| 532 | if (offset) |
| 533 | return -ESPIPE; |
| 534 | |
liu chuansheng | 5c53d81 | 2012-07-06 09:50:08 -0700 | [diff] [blame] | 535 | raw_spin_lock_irq(&logbuf_lock); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 536 | switch (whence) { |
| 537 | case SEEK_SET: |
| 538 | /* the first record */ |
| 539 | user->idx = log_first_idx; |
| 540 | user->seq = log_first_seq; |
| 541 | break; |
| 542 | case SEEK_DATA: |
| 543 | /* |
| 544 | * The first record after the last SYSLOG_ACTION_CLEAR, |
| 545 | * like issued by 'dmesg -c'. Reading /dev/kmsg itself |
| 546 | * changes no global state, and does not clear anything. |
| 547 | */ |
| 548 | user->idx = clear_idx; |
| 549 | user->seq = clear_seq; |
| 550 | break; |
| 551 | case SEEK_END: |
| 552 | /* after the last record */ |
| 553 | user->idx = log_next_idx; |
| 554 | user->seq = log_next_seq; |
| 555 | break; |
| 556 | default: |
| 557 | ret = -EINVAL; |
| 558 | } |
liu chuansheng | 5c53d81 | 2012-07-06 09:50:08 -0700 | [diff] [blame] | 559 | raw_spin_unlock_irq(&logbuf_lock); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 560 | return ret; |
| 561 | } |
| 562 | |
| 563 | static unsigned int devkmsg_poll(struct file *file, poll_table *wait) |
| 564 | { |
| 565 | struct devkmsg_user *user = file->private_data; |
| 566 | int ret = 0; |
| 567 | |
| 568 | if (!user) |
| 569 | return POLLERR|POLLNVAL; |
| 570 | |
| 571 | poll_wait(file, &log_wait, wait); |
| 572 | |
liu chuansheng | 5c53d81 | 2012-07-06 09:50:08 -0700 | [diff] [blame] | 573 | raw_spin_lock_irq(&logbuf_lock); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 574 | if (user->seq < log_next_seq) { |
| 575 | /* return error when data has vanished underneath us */ |
| 576 | if (user->seq < log_first_seq) |
| 577 | ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; |
| 578 | ret = POLLIN|POLLRDNORM; |
| 579 | } |
liu chuansheng | 5c53d81 | 2012-07-06 09:50:08 -0700 | [diff] [blame] | 580 | raw_spin_unlock_irq(&logbuf_lock); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 581 | |
| 582 | return ret; |
| 583 | } |
| 584 | |
| 585 | static int devkmsg_open(struct inode *inode, struct file *file) |
| 586 | { |
| 587 | struct devkmsg_user *user; |
| 588 | int err; |
| 589 | |
| 590 | /* write-only does not need any file context */ |
| 591 | if ((file->f_flags & O_ACCMODE) == O_WRONLY) |
| 592 | return 0; |
| 593 | |
| 594 | err = security_syslog(SYSLOG_ACTION_READ_ALL); |
| 595 | if (err) |
| 596 | return err; |
| 597 | |
| 598 | user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); |
| 599 | if (!user) |
| 600 | return -ENOMEM; |
| 601 | |
| 602 | mutex_init(&user->lock); |
| 603 | |
liu chuansheng | 5c53d81 | 2012-07-06 09:50:08 -0700 | [diff] [blame] | 604 | raw_spin_lock_irq(&logbuf_lock); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 605 | user->idx = log_first_idx; |
| 606 | user->seq = log_first_seq; |
liu chuansheng | 5c53d81 | 2012-07-06 09:50:08 -0700 | [diff] [blame] | 607 | raw_spin_unlock_irq(&logbuf_lock); |
Kay Sievers | e11fea9 | 2012-05-03 02:29:41 +0200 | [diff] [blame] | 608 | |
| 609 | file->private_data = user; |
| 610 | return 0; |
| 611 | } |
| 612 | |
| 613 | static int devkmsg_release(struct inode *inode, struct file *file) |
| 614 | { |
| 615 | struct devkmsg_user *user = file->private_data; |
| 616 | |
| 617 | if (!user) |
| 618 | return 0; |
| 619 | |
| 620 | mutex_destroy(&user->lock); |
| 621 | kfree(user); |
| 622 | return 0; |
| 623 | } |
| 624 | |
| 625 | const struct file_operations kmsg_fops = { |
| 626 | .open = devkmsg_open, |
| 627 | .read = devkmsg_read, |
| 628 | .aio_write = devkmsg_writev, |
| 629 | .llseek = devkmsg_llseek, |
| 630 | .poll = devkmsg_poll, |
| 631 | .release = devkmsg_release, |
| 632 | }; |
| 633 | |
Neil Horman | 04d491a | 2009-04-02 16:58:57 -0700 | [diff] [blame] | 634 | #ifdef CONFIG_KEXEC |
| 635 | /* |
| 636 | * This appends the listed symbols to /proc/vmcoreinfo |
| 637 | * |
| 638 | * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to |
| 639 | * obtain access to symbols that are otherwise very difficult to locate. These |
| 640 | * symbols are specifically used so that utilities can access and extract the |
| 641 | * dmesg log from a vmcore file after a crash. |
| 642 | */ |
| 643 | void log_buf_kexec_setup(void) |
| 644 | { |
| 645 | VMCOREINFO_SYMBOL(log_buf); |
Neil Horman | 04d491a | 2009-04-02 16:58:57 -0700 | [diff] [blame] | 646 | VMCOREINFO_SYMBOL(log_buf_len); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 647 | VMCOREINFO_SYMBOL(log_first_idx); |
| 648 | VMCOREINFO_SYMBOL(log_next_idx); |
Neil Horman | 04d491a | 2009-04-02 16:58:57 -0700 | [diff] [blame] | 649 | } |
| 650 | #endif |
| 651 | |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 652 | /* requested log_buf_len from kernel cmdline */ |
| 653 | static unsigned long __initdata new_log_buf_len; |
| 654 | |
| 655 | /* save requested log_buf_len since it's too early to process it */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | static int __init log_buf_len_setup(char *str) |
| 657 | { |
Denys Vlasenko | eed4a2a | 2008-02-06 01:37:02 -0800 | [diff] [blame] | 658 | unsigned size = memparse(str, &str); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | |
| 660 | if (size) |
| 661 | size = roundup_pow_of_two(size); |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 662 | if (size > log_buf_len) |
| 663 | new_log_buf_len = size; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 665 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 666 | } |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 667 | early_param("log_buf_len", log_buf_len_setup); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 668 | |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 669 | void __init setup_log_buf(int early) |
| 670 | { |
| 671 | unsigned long flags; |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 672 | char *new_log_buf; |
| 673 | int free; |
| 674 | |
| 675 | if (!new_log_buf_len) |
| 676 | return; |
| 677 | |
| 678 | if (early) { |
| 679 | unsigned long mem; |
| 680 | |
| 681 | mem = memblock_alloc(new_log_buf_len, PAGE_SIZE); |
Tejun Heo | 1f5026a | 2011-07-12 09:58:09 +0200 | [diff] [blame] | 682 | if (!mem) |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 683 | return; |
| 684 | new_log_buf = __va(mem); |
| 685 | } else { |
| 686 | new_log_buf = alloc_bootmem_nopanic(new_log_buf_len); |
| 687 | } |
| 688 | |
| 689 | if (unlikely(!new_log_buf)) { |
| 690 | pr_err("log_buf_len: %ld bytes not available\n", |
| 691 | new_log_buf_len); |
| 692 | return; |
| 693 | } |
| 694 | |
Thomas Gleixner | 07354eb | 2009-07-25 17:50:36 +0200 | [diff] [blame] | 695 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 696 | log_buf_len = new_log_buf_len; |
| 697 | log_buf = new_log_buf; |
| 698 | new_log_buf_len = 0; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 699 | free = __LOG_BUF_LEN - log_next_idx; |
| 700 | memcpy(log_buf, __log_buf, __LOG_BUF_LEN); |
Thomas Gleixner | 07354eb | 2009-07-25 17:50:36 +0200 | [diff] [blame] | 701 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
Mike Travis | 162a7e7 | 2011-05-24 17:13:20 -0700 | [diff] [blame] | 702 | |
| 703 | pr_info("log_buf_len: %d\n", log_buf_len); |
| 704 | pr_info("early log buf free: %d(%d%%)\n", |
| 705 | free, (free * 100) / __LOG_BUF_LEN); |
| 706 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 707 | |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 708 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
| 709 | |
Namhyung Kim | 674dff6 | 2010-10-26 14:22:48 -0700 | [diff] [blame] | 710 | static int boot_delay; /* msecs delay after each printk during bootup */ |
Dave Young | 3a3b6ed | 2009-09-22 16:43:31 -0700 | [diff] [blame] | 711 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 712 | |
| 713 | static int __init boot_delay_setup(char *str) |
| 714 | { |
| 715 | unsigned long lpj; |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 716 | |
| 717 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ |
| 718 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; |
| 719 | |
| 720 | get_option(&str, &boot_delay); |
| 721 | if (boot_delay > 10 * 1000) |
| 722 | boot_delay = 0; |
| 723 | |
Dave Young | 3a3b6ed | 2009-09-22 16:43:31 -0700 | [diff] [blame] | 724 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
| 725 | "HZ: %d, loops_per_msec: %llu\n", |
| 726 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 727 | return 1; |
| 728 | } |
| 729 | __setup("boot_delay=", boot_delay_setup); |
| 730 | |
| 731 | static void boot_delay_msec(void) |
| 732 | { |
| 733 | unsigned long long k; |
| 734 | unsigned long timeout; |
| 735 | |
| 736 | if (boot_delay == 0 || system_state != SYSTEM_BOOTING) |
| 737 | return; |
| 738 | |
Dave Young | 3a3b6ed | 2009-09-22 16:43:31 -0700 | [diff] [blame] | 739 | k = (unsigned long long)loops_per_msec * boot_delay; |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 740 | |
| 741 | timeout = jiffies + msecs_to_jiffies(boot_delay); |
| 742 | while (k) { |
| 743 | k--; |
| 744 | cpu_relax(); |
| 745 | /* |
| 746 | * use (volatile) jiffies to prevent |
| 747 | * compiler reduction; loop termination via jiffies |
| 748 | * is secondary and may or may not happen. |
| 749 | */ |
| 750 | if (time_after(jiffies, timeout)) |
| 751 | break; |
| 752 | touch_nmi_watchdog(); |
| 753 | } |
| 754 | } |
| 755 | #else |
| 756 | static inline void boot_delay_msec(void) |
| 757 | { |
| 758 | } |
| 759 | #endif |
| 760 | |
Dan Rosenberg | eaf06b2 | 2010-11-11 14:05:18 -0800 | [diff] [blame] | 761 | #ifdef CONFIG_SECURITY_DMESG_RESTRICT |
| 762 | int dmesg_restrict = 1; |
| 763 | #else |
| 764 | int dmesg_restrict; |
| 765 | #endif |
| 766 | |
Linus Torvalds | ee24aeb | 2011-02-10 17:53:55 -0800 | [diff] [blame] | 767 | static int syslog_action_restricted(int type) |
| 768 | { |
| 769 | if (dmesg_restrict) |
| 770 | return 1; |
| 771 | /* Unless restricted, we allow "read all" and "get buffer size" for everybody */ |
| 772 | return type != SYSLOG_ACTION_READ_ALL && type != SYSLOG_ACTION_SIZE_BUFFER; |
| 773 | } |
| 774 | |
| 775 | static int check_syslog_permissions(int type, bool from_file) |
| 776 | { |
| 777 | /* |
| 778 | * If this is from /proc/kmsg and we've already opened it, then we've |
| 779 | * already done the capabilities checks at open time. |
| 780 | */ |
| 781 | if (from_file && type != SYSLOG_ACTION_OPEN) |
| 782 | return 0; |
| 783 | |
| 784 | if (syslog_action_restricted(type)) { |
| 785 | if (capable(CAP_SYSLOG)) |
| 786 | return 0; |
| 787 | /* For historical reasons, accept CAP_SYS_ADMIN too, with a warning */ |
| 788 | if (capable(CAP_SYS_ADMIN)) { |
Jonathan Nieder | f2c0d02 | 2011-08-08 06:22:43 +0200 | [diff] [blame] | 789 | printk_once(KERN_WARNING "%s (%d): " |
| 790 | "Attempt to access syslog with CAP_SYS_ADMIN " |
| 791 | "but no CAP_SYSLOG (deprecated).\n", |
| 792 | current->comm, task_pid_nr(current)); |
Linus Torvalds | ee24aeb | 2011-02-10 17:53:55 -0800 | [diff] [blame] | 793 | return 0; |
| 794 | } |
| 795 | return -EPERM; |
| 796 | } |
| 797 | return 0; |
| 798 | } |
| 799 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 800 | #if defined(CONFIG_PRINTK_TIME) |
| 801 | static bool printk_time = 1; |
| 802 | #else |
| 803 | static bool printk_time; |
| 804 | #endif |
| 805 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); |
| 806 | |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 807 | static size_t print_time(u64 ts, char *buf) |
| 808 | { |
| 809 | unsigned long rem_nsec; |
| 810 | |
| 811 | if (!printk_time) |
| 812 | return 0; |
| 813 | |
| 814 | if (!buf) |
| 815 | return 15; |
| 816 | |
| 817 | rem_nsec = do_div(ts, 1000000000); |
| 818 | return sprintf(buf, "[%5lu.%06lu] ", |
| 819 | (unsigned long)ts, rem_nsec / 1000); |
| 820 | } |
| 821 | |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 822 | static size_t print_prefix(const struct log *msg, bool syslog, char *buf) |
Kay Sievers | 649e6ee | 2012-05-10 04:30:45 +0200 | [diff] [blame] | 823 | { |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 824 | size_t len = 0; |
Kay Sievers | 43a73a5 | 2012-07-06 09:50:09 -0700 | [diff] [blame] | 825 | unsigned int prefix = (msg->facility << 3) | msg->level; |
Kay Sievers | 649e6ee | 2012-05-10 04:30:45 +0200 | [diff] [blame] | 826 | |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 827 | if (syslog) { |
| 828 | if (buf) { |
Kay Sievers | 43a73a5 | 2012-07-06 09:50:09 -0700 | [diff] [blame] | 829 | len += sprintf(buf, "<%u>", prefix); |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 830 | } else { |
| 831 | len += 3; |
Kay Sievers | 43a73a5 | 2012-07-06 09:50:09 -0700 | [diff] [blame] | 832 | if (prefix > 999) |
| 833 | len += 3; |
| 834 | else if (prefix > 99) |
| 835 | len += 2; |
| 836 | else if (prefix > 9) |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 837 | len++; |
| 838 | } |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 839 | } |
| 840 | |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 841 | len += print_time(msg->ts_nsec, buf ? buf + len : NULL); |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 842 | return len; |
| 843 | } |
| 844 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 845 | static size_t msg_print_text(const struct log *msg, enum log_flags prev, |
| 846 | bool syslog, char *buf, size_t size) |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 847 | { |
| 848 | const char *text = log_text(msg); |
| 849 | size_t text_size = msg->text_len; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 850 | bool prefix = true; |
| 851 | bool newline = true; |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 852 | size_t len = 0; |
| 853 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 854 | if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) |
| 855 | prefix = false; |
| 856 | |
| 857 | if (msg->flags & LOG_CONT) { |
| 858 | if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE)) |
| 859 | prefix = false; |
| 860 | |
| 861 | if (!(msg->flags & LOG_NEWLINE)) |
| 862 | newline = false; |
| 863 | } |
| 864 | |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 865 | do { |
| 866 | const char *next = memchr(text, '\n', text_size); |
| 867 | size_t text_len; |
| 868 | |
| 869 | if (next) { |
| 870 | text_len = next - text; |
| 871 | next++; |
| 872 | text_size -= next - text; |
| 873 | } else { |
| 874 | text_len = text_size; |
| 875 | } |
| 876 | |
| 877 | if (buf) { |
| 878 | if (print_prefix(msg, syslog, NULL) + |
| 879 | text_len + 1>= size - len) |
| 880 | break; |
| 881 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 882 | if (prefix) |
| 883 | len += print_prefix(msg, syslog, buf + len); |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 884 | memcpy(buf + len, text, text_len); |
| 885 | len += text_len; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 886 | if (next || newline) |
| 887 | buf[len++] = '\n'; |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 888 | } else { |
| 889 | /* SYSLOG_ACTION_* buffer size only calculation */ |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 890 | if (prefix) |
| 891 | len += print_prefix(msg, syslog, NULL); |
| 892 | len += text_len; |
| 893 | if (next || newline) |
| 894 | len++; |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 895 | } |
| 896 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 897 | prefix = true; |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 898 | text = next; |
| 899 | } while (text); |
| 900 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 901 | return len; |
| 902 | } |
| 903 | |
| 904 | static int syslog_print(char __user *buf, int size) |
| 905 | { |
| 906 | char *text; |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 907 | struct log *msg; |
Jan Beulich | 116e90b | 2012-06-22 16:36:09 +0100 | [diff] [blame] | 908 | int len = 0; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 909 | |
| 910 | text = kmalloc(LOG_LINE_MAX, GFP_KERNEL); |
| 911 | if (!text) |
| 912 | return -ENOMEM; |
| 913 | |
Jan Beulich | 116e90b | 2012-06-22 16:36:09 +0100 | [diff] [blame] | 914 | while (size > 0) { |
| 915 | size_t n; |
Kay Sievers | eb02dac | 2012-07-09 10:05:10 -0700 | [diff] [blame] | 916 | size_t skip; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 917 | |
Jan Beulich | 116e90b | 2012-06-22 16:36:09 +0100 | [diff] [blame] | 918 | raw_spin_lock_irq(&logbuf_lock); |
| 919 | if (syslog_seq < log_first_seq) { |
| 920 | /* messages are gone, move to first one */ |
| 921 | syslog_seq = log_first_seq; |
| 922 | syslog_idx = log_first_idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 923 | syslog_prev = 0; |
Kay Sievers | eb02dac | 2012-07-09 10:05:10 -0700 | [diff] [blame] | 924 | syslog_partial = 0; |
Jan Beulich | 116e90b | 2012-06-22 16:36:09 +0100 | [diff] [blame] | 925 | } |
| 926 | if (syslog_seq == log_next_seq) { |
| 927 | raw_spin_unlock_irq(&logbuf_lock); |
| 928 | break; |
| 929 | } |
Kay Sievers | eb02dac | 2012-07-09 10:05:10 -0700 | [diff] [blame] | 930 | |
| 931 | skip = syslog_partial; |
Jan Beulich | 116e90b | 2012-06-22 16:36:09 +0100 | [diff] [blame] | 932 | msg = log_from_idx(syslog_idx); |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 933 | n = msg_print_text(msg, syslog_prev, true, text, LOG_LINE_MAX); |
Kay Sievers | eb02dac | 2012-07-09 10:05:10 -0700 | [diff] [blame] | 934 | if (n - syslog_partial <= size) { |
| 935 | /* message fits into buffer, move forward */ |
Jan Beulich | 116e90b | 2012-06-22 16:36:09 +0100 | [diff] [blame] | 936 | syslog_idx = log_next(syslog_idx); |
| 937 | syslog_seq++; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 938 | syslog_prev = msg->flags; |
Kay Sievers | eb02dac | 2012-07-09 10:05:10 -0700 | [diff] [blame] | 939 | n -= syslog_partial; |
| 940 | syslog_partial = 0; |
| 941 | } else if (!len){ |
| 942 | /* partial read(), remember position */ |
| 943 | n = size; |
| 944 | syslog_partial += n; |
Jan Beulich | 116e90b | 2012-06-22 16:36:09 +0100 | [diff] [blame] | 945 | } else |
| 946 | n = 0; |
| 947 | raw_spin_unlock_irq(&logbuf_lock); |
| 948 | |
| 949 | if (!n) |
| 950 | break; |
| 951 | |
Kay Sievers | eb02dac | 2012-07-09 10:05:10 -0700 | [diff] [blame] | 952 | if (copy_to_user(buf, text + skip, n)) { |
Jan Beulich | 116e90b | 2012-06-22 16:36:09 +0100 | [diff] [blame] | 953 | if (!len) |
| 954 | len = -EFAULT; |
| 955 | break; |
| 956 | } |
Kay Sievers | eb02dac | 2012-07-09 10:05:10 -0700 | [diff] [blame] | 957 | |
| 958 | len += n; |
| 959 | size -= n; |
| 960 | buf += n; |
Jan Beulich | 116e90b | 2012-06-22 16:36:09 +0100 | [diff] [blame] | 961 | } |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 962 | |
| 963 | kfree(text); |
| 964 | return len; |
| 965 | } |
| 966 | |
| 967 | static int syslog_print_all(char __user *buf, int size, bool clear) |
| 968 | { |
| 969 | char *text; |
| 970 | int len = 0; |
| 971 | |
| 972 | text = kmalloc(LOG_LINE_MAX, GFP_KERNEL); |
| 973 | if (!text) |
| 974 | return -ENOMEM; |
| 975 | |
| 976 | raw_spin_lock_irq(&logbuf_lock); |
| 977 | if (buf) { |
| 978 | u64 next_seq; |
| 979 | u64 seq; |
| 980 | u32 idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 981 | enum log_flags prev; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 982 | |
| 983 | if (clear_seq < log_first_seq) { |
| 984 | /* messages are gone, move to first available one */ |
| 985 | clear_seq = log_first_seq; |
| 986 | clear_idx = log_first_idx; |
| 987 | } |
| 988 | |
| 989 | /* |
| 990 | * Find first record that fits, including all following records, |
| 991 | * into the user-provided buffer for this dump. |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 992 | */ |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 993 | seq = clear_seq; |
| 994 | idx = clear_idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 995 | prev = 0; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 996 | while (seq < log_next_seq) { |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 997 | struct log *msg = log_from_idx(idx); |
| 998 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 999 | len += msg_print_text(msg, prev, true, NULL, 0); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1000 | idx = log_next(idx); |
| 1001 | seq++; |
| 1002 | } |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 1003 | |
| 1004 | /* move first record forward until length fits into the buffer */ |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1005 | seq = clear_seq; |
| 1006 | idx = clear_idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1007 | prev = 0; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1008 | while (len > size && seq < log_next_seq) { |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 1009 | struct log *msg = log_from_idx(idx); |
| 1010 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1011 | len -= msg_print_text(msg, prev, true, NULL, 0); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1012 | idx = log_next(idx); |
| 1013 | seq++; |
| 1014 | } |
| 1015 | |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 1016 | /* last message fitting into this dump */ |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1017 | next_seq = log_next_seq; |
| 1018 | |
| 1019 | len = 0; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1020 | prev = 0; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1021 | while (len >= 0 && seq < next_seq) { |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 1022 | struct log *msg = log_from_idx(idx); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1023 | int textlen; |
| 1024 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1025 | textlen = msg_print_text(msg, prev, true, text, LOG_LINE_MAX); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1026 | if (textlen < 0) { |
| 1027 | len = textlen; |
| 1028 | break; |
| 1029 | } |
| 1030 | idx = log_next(idx); |
| 1031 | seq++; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1032 | prev = msg->flags; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1033 | |
| 1034 | raw_spin_unlock_irq(&logbuf_lock); |
| 1035 | if (copy_to_user(buf + len, text, textlen)) |
| 1036 | len = -EFAULT; |
| 1037 | else |
| 1038 | len += textlen; |
| 1039 | raw_spin_lock_irq(&logbuf_lock); |
| 1040 | |
| 1041 | if (seq < log_first_seq) { |
| 1042 | /* messages are gone, move to next one */ |
| 1043 | seq = log_first_seq; |
| 1044 | idx = log_first_idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1045 | prev = 0; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1046 | } |
| 1047 | } |
| 1048 | } |
| 1049 | |
| 1050 | if (clear) { |
| 1051 | clear_seq = log_next_seq; |
| 1052 | clear_idx = log_next_idx; |
| 1053 | } |
| 1054 | raw_spin_unlock_irq(&logbuf_lock); |
| 1055 | |
| 1056 | kfree(text); |
| 1057 | return len; |
| 1058 | } |
| 1059 | |
Kees Cook | 0023459 | 2010-02-03 15:36:43 -0800 | [diff] [blame] | 1060 | int do_syslog(int type, char __user *buf, int len, bool from_file) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1061 | { |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1062 | bool clear = false; |
| 1063 | static int saved_console_loglevel = -1; |
Linus Torvalds | ee24aeb | 2011-02-10 17:53:55 -0800 | [diff] [blame] | 1064 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1065 | |
Linus Torvalds | ee24aeb | 2011-02-10 17:53:55 -0800 | [diff] [blame] | 1066 | error = check_syslog_permissions(type, from_file); |
| 1067 | if (error) |
| 1068 | goto out; |
Eric Paris | 12b3052 | 2010-11-15 18:36:29 -0500 | [diff] [blame] | 1069 | |
| 1070 | error = security_syslog(type); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1071 | if (error) |
| 1072 | return error; |
| 1073 | |
| 1074 | switch (type) { |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 1075 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1076 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 1077 | case SYSLOG_ACTION_OPEN: /* Open log */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1078 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 1079 | case SYSLOG_ACTION_READ: /* Read from log */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1080 | error = -EINVAL; |
| 1081 | if (!buf || len < 0) |
| 1082 | goto out; |
| 1083 | error = 0; |
| 1084 | if (!len) |
| 1085 | goto out; |
| 1086 | if (!access_ok(VERIFY_WRITE, buf, len)) { |
| 1087 | error = -EFAULT; |
| 1088 | goto out; |
| 1089 | } |
Yuanhan Liu | 4a77a5a | 2012-06-16 21:21:51 +0800 | [diff] [blame] | 1090 | error = wait_event_interruptible(log_wait, |
| 1091 | syslog_seq != log_next_seq); |
Kay Sievers | cb424ff | 2012-07-06 09:50:09 -0700 | [diff] [blame] | 1092 | if (error) |
Yuanhan Liu | 4a77a5a | 2012-06-16 21:21:51 +0800 | [diff] [blame] | 1093 | goto out; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1094 | error = syslog_print(buf, len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1095 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 1096 | /* Read/clear last kernel messages */ |
| 1097 | case SYSLOG_ACTION_READ_CLEAR: |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1098 | clear = true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1099 | /* FALL THRU */ |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 1100 | /* Read last kernel messages */ |
| 1101 | case SYSLOG_ACTION_READ_ALL: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1102 | error = -EINVAL; |
| 1103 | if (!buf || len < 0) |
| 1104 | goto out; |
| 1105 | error = 0; |
| 1106 | if (!len) |
| 1107 | goto out; |
| 1108 | if (!access_ok(VERIFY_WRITE, buf, len)) { |
| 1109 | error = -EFAULT; |
| 1110 | goto out; |
| 1111 | } |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1112 | error = syslog_print_all(buf, len, clear); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1113 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 1114 | /* Clear ring buffer */ |
| 1115 | case SYSLOG_ACTION_CLEAR: |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1116 | syslog_print_all(NULL, 0, true); |
Alan Stern | 4661e35 | 2012-06-22 17:12:19 -0400 | [diff] [blame] | 1117 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 1118 | /* Disable logging to console */ |
| 1119 | case SYSLOG_ACTION_CONSOLE_OFF: |
Frans Pop | 1aaad49 | 2009-07-06 13:31:48 +0200 | [diff] [blame] | 1120 | if (saved_console_loglevel == -1) |
| 1121 | saved_console_loglevel = console_loglevel; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1122 | console_loglevel = minimum_console_loglevel; |
| 1123 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 1124 | /* Enable logging to console */ |
| 1125 | case SYSLOG_ACTION_CONSOLE_ON: |
Frans Pop | 1aaad49 | 2009-07-06 13:31:48 +0200 | [diff] [blame] | 1126 | if (saved_console_loglevel != -1) { |
| 1127 | console_loglevel = saved_console_loglevel; |
| 1128 | saved_console_loglevel = -1; |
| 1129 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1130 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 1131 | /* Set level of messages printed to console */ |
| 1132 | case SYSLOG_ACTION_CONSOLE_LEVEL: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1133 | error = -EINVAL; |
| 1134 | if (len < 1 || len > 8) |
| 1135 | goto out; |
| 1136 | if (len < minimum_console_loglevel) |
| 1137 | len = minimum_console_loglevel; |
| 1138 | console_loglevel = len; |
Frans Pop | 1aaad49 | 2009-07-06 13:31:48 +0200 | [diff] [blame] | 1139 | /* Implicitly re-enable logging to console */ |
| 1140 | saved_console_loglevel = -1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1141 | error = 0; |
| 1142 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 1143 | /* Number of chars in the log buffer */ |
| 1144 | case SYSLOG_ACTION_SIZE_UNREAD: |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1145 | raw_spin_lock_irq(&logbuf_lock); |
| 1146 | if (syslog_seq < log_first_seq) { |
| 1147 | /* messages are gone, move to first one */ |
| 1148 | syslog_seq = log_first_seq; |
| 1149 | syslog_idx = log_first_idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1150 | syslog_prev = 0; |
Kay Sievers | eb02dac | 2012-07-09 10:05:10 -0700 | [diff] [blame] | 1151 | syslog_partial = 0; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1152 | } |
| 1153 | if (from_file) { |
| 1154 | /* |
| 1155 | * Short-cut for poll(/"proc/kmsg") which simply checks |
| 1156 | * for pending data, not the size; return the count of |
| 1157 | * records, not the length. |
| 1158 | */ |
| 1159 | error = log_next_idx - syslog_idx; |
| 1160 | } else { |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1161 | u64 seq = syslog_seq; |
| 1162 | u32 idx = syslog_idx; |
| 1163 | enum log_flags prev = syslog_prev; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1164 | |
| 1165 | error = 0; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1166 | while (seq < log_next_seq) { |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 1167 | struct log *msg = log_from_idx(idx); |
| 1168 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1169 | error += msg_print_text(msg, prev, true, NULL, 0); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1170 | idx = log_next(idx); |
| 1171 | seq++; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1172 | prev = msg->flags; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1173 | } |
Kay Sievers | eb02dac | 2012-07-09 10:05:10 -0700 | [diff] [blame] | 1174 | error -= syslog_partial; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1175 | } |
| 1176 | raw_spin_unlock_irq(&logbuf_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1177 | break; |
Kees Cook | d78ca3c | 2010-02-03 15:37:13 -0800 | [diff] [blame] | 1178 | /* Size of the log buffer */ |
| 1179 | case SYSLOG_ACTION_SIZE_BUFFER: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1180 | error = log_buf_len; |
| 1181 | break; |
| 1182 | default: |
| 1183 | error = -EINVAL; |
| 1184 | break; |
| 1185 | } |
| 1186 | out: |
| 1187 | return error; |
| 1188 | } |
| 1189 | |
Heiko Carstens | 1e7bfb2 | 2009-01-14 14:14:29 +0100 | [diff] [blame] | 1190 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1191 | { |
Kees Cook | 0023459 | 2010-02-03 15:36:43 -0800 | [diff] [blame] | 1192 | return do_syslog(type, buf, len, SYSLOG_FROM_CALL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1193 | } |
| 1194 | |
Rusty Russell | 2329abf | 2012-01-13 09:32:18 +1030 | [diff] [blame] | 1195 | static bool __read_mostly ignore_loglevel; |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 1196 | |
Adrian Bunk | 99eea6a | 2006-12-22 01:07:00 -0800 | [diff] [blame] | 1197 | static int __init ignore_loglevel_setup(char *str) |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 1198 | { |
| 1199 | ignore_loglevel = 1; |
| 1200 | printk(KERN_INFO "debug: ignoring loglevel setting.\n"); |
| 1201 | |
Ingo Molnar | c4772d9 | 2008-01-31 22:45:23 +0100 | [diff] [blame] | 1202 | return 0; |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 1203 | } |
| 1204 | |
Ingo Molnar | c4772d9 | 2008-01-31 22:45:23 +0100 | [diff] [blame] | 1205 | early_param("ignore_loglevel", ignore_loglevel_setup); |
Rusty Russell | 29d4d6d | 2012-01-13 09:32:17 +1030 | [diff] [blame] | 1206 | module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); |
Yanmin Zhang | 0eca6b7 | 2011-10-31 17:11:25 -0700 | [diff] [blame] | 1207 | MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to" |
| 1208 | "print all kernel messages to the console."); |
Ingo Molnar | 79290822 | 2006-12-06 20:40:51 -0800 | [diff] [blame] | 1209 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1210 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1211 | * Call the console drivers, asking them to write out |
| 1212 | * log_buf[start] to log_buf[end - 1]. |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1213 | * The console_lock must be held. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1214 | */ |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1215 | static void call_console_drivers(int level, const char *text, size_t len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1216 | { |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1217 | struct console *con; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1218 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1219 | trace_console(text, 0, len, len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1220 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1221 | if (level >= console_loglevel && !ignore_loglevel) |
| 1222 | return; |
| 1223 | if (!console_drivers) |
| 1224 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1225 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1226 | for_each_console(con) { |
| 1227 | if (exclusive_console && con != exclusive_console) |
| 1228 | continue; |
| 1229 | if (!(con->flags & CON_ENABLED)) |
| 1230 | continue; |
| 1231 | if (!con->write) |
| 1232 | continue; |
| 1233 | if (!cpu_online(smp_processor_id()) && |
| 1234 | !(con->flags & CON_ANYTIME)) |
| 1235 | continue; |
| 1236 | con->write(con, text, len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1237 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1238 | } |
| 1239 | |
| 1240 | /* |
| 1241 | * Zap console related locks when oopsing. Only zap at most once |
| 1242 | * every 10 seconds, to leave time for slow consoles to print a |
| 1243 | * full oops. |
| 1244 | */ |
| 1245 | static void zap_locks(void) |
| 1246 | { |
| 1247 | static unsigned long oops_timestamp; |
| 1248 | |
| 1249 | if (time_after_eq(jiffies, oops_timestamp) && |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 1250 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1251 | return; |
| 1252 | |
| 1253 | oops_timestamp = jiffies; |
| 1254 | |
Peter Zijlstra | 94d24fc | 2011-06-07 11:17:30 +0200 | [diff] [blame] | 1255 | debug_locks_off(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1256 | /* If a crash is occurring, make sure we can't deadlock */ |
Thomas Gleixner | 07354eb | 2009-07-25 17:50:36 +0200 | [diff] [blame] | 1257 | raw_spin_lock_init(&logbuf_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1258 | /* And make sure that we print immediately */ |
Thomas Gleixner | 5b8c4f2 | 2010-09-07 14:33:43 +0000 | [diff] [blame] | 1259 | sema_init(&console_sem, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1260 | } |
| 1261 | |
Michael Ellerman | 76a8ad2 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 1262 | /* Check if we have any console registered that can be called early in boot. */ |
| 1263 | static int have_callable_console(void) |
| 1264 | { |
| 1265 | struct console *con; |
| 1266 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 1267 | for_each_console(con) |
Michael Ellerman | 76a8ad2 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 1268 | if (con->flags & CON_ANYTIME) |
| 1269 | return 1; |
| 1270 | |
| 1271 | return 0; |
| 1272 | } |
| 1273 | |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 1274 | /* |
| 1275 | * Can we actually use the console at this time on this cpu? |
| 1276 | * |
| 1277 | * Console drivers may assume that per-cpu resources have |
| 1278 | * been allocated. So unless they're explicitly marked as |
| 1279 | * being able to cope (CON_ANYTIME) don't call them until |
| 1280 | * this CPU is officially up. |
| 1281 | */ |
| 1282 | static inline int can_use_console(unsigned int cpu) |
| 1283 | { |
| 1284 | return cpu_online(cpu) || have_callable_console(); |
| 1285 | } |
| 1286 | |
| 1287 | /* |
| 1288 | * Try to get console ownership to actually show the kernel |
| 1289 | * messages from a 'printk'. Return true (and with the |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1290 | * console_lock held, and 'console_locked' set) if it |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 1291 | * is successful, false otherwise. |
| 1292 | * |
| 1293 | * This gets called with the 'logbuf_lock' spinlock held and |
| 1294 | * interrupts disabled. It should return with 'lockbuf_lock' |
| 1295 | * released but interrupts still disabled. |
| 1296 | */ |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1297 | static int console_trylock_for_printk(unsigned int cpu) |
Namhyung Kim | 8155c02 | 2010-10-26 14:22:47 -0700 | [diff] [blame] | 1298 | __releases(&logbuf_lock) |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 1299 | { |
Peter Zijlstra | 0b5e1c5 | 2011-06-07 11:15:33 +0200 | [diff] [blame] | 1300 | int retval = 0, wake = 0; |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 1301 | |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1302 | if (console_trylock()) { |
Linus Torvalds | 093a07e | 2008-04-15 13:09:54 -0700 | [diff] [blame] | 1303 | retval = 1; |
| 1304 | |
| 1305 | /* |
| 1306 | * If we can't use the console, we need to release |
| 1307 | * the console semaphore by hand to avoid flushing |
| 1308 | * the buffer. We need to hold the console semaphore |
| 1309 | * in order to do this test safely. |
| 1310 | */ |
| 1311 | if (!can_use_console(cpu)) { |
| 1312 | console_locked = 0; |
Peter Zijlstra | 0b5e1c5 | 2011-06-07 11:15:33 +0200 | [diff] [blame] | 1313 | wake = 1; |
Linus Torvalds | 093a07e | 2008-04-15 13:09:54 -0700 | [diff] [blame] | 1314 | retval = 0; |
| 1315 | } |
| 1316 | } |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1317 | logbuf_cpu = UINT_MAX; |
Peter Zijlstra | 0b5e1c5 | 2011-06-07 11:15:33 +0200 | [diff] [blame] | 1318 | if (wake) |
| 1319 | up(&console_sem); |
Thomas Gleixner | 07354eb | 2009-07-25 17:50:36 +0200 | [diff] [blame] | 1320 | raw_spin_unlock(&logbuf_lock); |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 1321 | return retval; |
| 1322 | } |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 1323 | |
Dave Young | af91322 | 2009-09-22 16:43:33 -0700 | [diff] [blame] | 1324 | int printk_delay_msec __read_mostly; |
| 1325 | |
| 1326 | static inline void printk_delay(void) |
| 1327 | { |
| 1328 | if (unlikely(printk_delay_msec)) { |
| 1329 | int m = printk_delay_msec; |
| 1330 | |
| 1331 | while (m--) { |
| 1332 | mdelay(1); |
| 1333 | touch_nmi_watchdog(); |
| 1334 | } |
| 1335 | } |
| 1336 | } |
| 1337 | |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1338 | /* |
| 1339 | * Continuation lines are buffered, and not committed to the record buffer |
| 1340 | * until the line is complete, or a race forces it. The line fragments |
| 1341 | * though, are printed immediately to the consoles to ensure everything has |
| 1342 | * reached the console in case of a kernel crash. |
| 1343 | */ |
| 1344 | static struct cont { |
| 1345 | char buf[LOG_LINE_MAX]; |
| 1346 | size_t len; /* length == 0 means unused buffer */ |
| 1347 | size_t cons; /* bytes written to console */ |
| 1348 | struct task_struct *owner; /* task of first print*/ |
| 1349 | u64 ts_nsec; /* time of first print */ |
| 1350 | u8 level; /* log level of first message */ |
| 1351 | u8 facility; /* log level of first message */ |
| 1352 | bool flushed:1; /* buffer sealed and committed */ |
| 1353 | } cont; |
| 1354 | |
| 1355 | static void cont_flush(void) |
| 1356 | { |
| 1357 | if (cont.flushed) |
| 1358 | return; |
| 1359 | if (cont.len == 0) |
| 1360 | return; |
| 1361 | |
| 1362 | log_store(cont.facility, cont.level, LOG_NOCONS, cont.ts_nsec, |
| 1363 | NULL, 0, cont.buf, cont.len); |
| 1364 | |
| 1365 | cont.flushed = true; |
| 1366 | } |
| 1367 | |
| 1368 | static bool cont_add(int facility, int level, const char *text, size_t len) |
| 1369 | { |
| 1370 | if (cont.len && cont.flushed) |
| 1371 | return false; |
| 1372 | |
| 1373 | if (cont.len + len > sizeof(cont.buf)) { |
| 1374 | cont_flush(); |
| 1375 | return false; |
| 1376 | } |
| 1377 | |
| 1378 | if (!cont.len) { |
| 1379 | cont.facility = facility; |
| 1380 | cont.level = level; |
| 1381 | cont.owner = current; |
| 1382 | cont.ts_nsec = local_clock(); |
| 1383 | cont.cons = 0; |
| 1384 | cont.flushed = false; |
| 1385 | } |
| 1386 | |
| 1387 | memcpy(cont.buf + cont.len, text, len); |
| 1388 | cont.len += len; |
| 1389 | return true; |
| 1390 | } |
| 1391 | |
| 1392 | static size_t cont_print_text(char *text, size_t size) |
| 1393 | { |
| 1394 | size_t textlen = 0; |
| 1395 | size_t len; |
| 1396 | |
| 1397 | if (cont.cons == 0) { |
| 1398 | textlen += print_time(cont.ts_nsec, text); |
| 1399 | size -= textlen; |
| 1400 | } |
| 1401 | |
| 1402 | len = cont.len - cont.cons; |
| 1403 | if (len > 0) { |
| 1404 | if (len+1 > size) |
| 1405 | len = size-1; |
| 1406 | memcpy(text + textlen, cont.buf + cont.cons, len); |
| 1407 | textlen += len; |
| 1408 | cont.cons = cont.len; |
| 1409 | } |
| 1410 | |
| 1411 | if (cont.flushed) { |
| 1412 | text[textlen++] = '\n'; |
| 1413 | /* got everything, release buffer */ |
| 1414 | cont.len = 0; |
| 1415 | } |
| 1416 | return textlen; |
| 1417 | } |
| 1418 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1419 | asmlinkage int vprintk_emit(int facility, int level, |
| 1420 | const char *dict, size_t dictlen, |
| 1421 | const char *fmt, va_list args) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1422 | { |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1423 | static int recursion_bug; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1424 | static char textbuf[LOG_LINE_MAX]; |
| 1425 | char *text = textbuf; |
Kay Sievers | c313af1 | 2012-05-14 20:46:27 +0200 | [diff] [blame] | 1426 | size_t text_len; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1427 | enum log_flags lflags = 0; |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 1428 | unsigned long flags; |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 1429 | int this_cpu; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1430 | int printed_len = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1431 | |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 1432 | boot_delay_msec(); |
Dave Young | af91322 | 2009-09-22 16:43:33 -0700 | [diff] [blame] | 1433 | printk_delay(); |
Randy Dunlap | bfe8df3 | 2007-10-16 01:23:46 -0700 | [diff] [blame] | 1434 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1435 | /* This stops the holder of console_sem just where we want him */ |
Peter Zijlstra | 1a9a8ae | 2011-06-07 11:17:30 +0200 | [diff] [blame] | 1436 | local_irq_save(flags); |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 1437 | this_cpu = smp_processor_id(); |
| 1438 | |
| 1439 | /* |
| 1440 | * Ouch, printk recursed into itself! |
| 1441 | */ |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1442 | if (unlikely(logbuf_cpu == this_cpu)) { |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 1443 | /* |
| 1444 | * If a crash is occurring during printk() on this CPU, |
| 1445 | * then try to get the crash message out but make sure |
| 1446 | * we can't deadlock. Otherwise just return to avoid the |
| 1447 | * recursion and return - but flag the recursion so that |
| 1448 | * it can be printed at the next appropriate moment: |
| 1449 | */ |
Peter Zijlstra | 94d24fc | 2011-06-07 11:17:30 +0200 | [diff] [blame] | 1450 | if (!oops_in_progress && !lockdep_recursing(current)) { |
Tejun Heo | 3b8945e | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 1451 | recursion_bug = 1; |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 1452 | goto out_restore_irqs; |
| 1453 | } |
| 1454 | zap_locks(); |
| 1455 | } |
| 1456 | |
Ingo Molnar | a0f1ccf | 2006-07-03 00:24:58 -0700 | [diff] [blame] | 1457 | lockdep_off(); |
Thomas Gleixner | 07354eb | 2009-07-25 17:50:36 +0200 | [diff] [blame] | 1458 | raw_spin_lock(&logbuf_lock); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1459 | logbuf_cpu = this_cpu; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1460 | |
Tejun Heo | 3b8945e | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 1461 | if (recursion_bug) { |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1462 | static const char recursion_msg[] = |
| 1463 | "BUG: recent printk recursion!"; |
| 1464 | |
Tejun Heo | 3b8945e | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 1465 | recursion_bug = 0; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1466 | printed_len += strlen(recursion_msg); |
| 1467 | /* emit KERN_CRIT message */ |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1468 | log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1469 | NULL, 0, recursion_msg, printed_len); |
Linus Torvalds | 5fd29d6 | 2009-06-16 10:57:02 -0700 | [diff] [blame] | 1470 | } |
| 1471 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1472 | /* |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1473 | * The printf needs to come first; we need the syslog |
| 1474 | * prefix which might be passed-in as a parameter. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1475 | */ |
Kay Sievers | c313af1 | 2012-05-14 20:46:27 +0200 | [diff] [blame] | 1476 | text_len = vscnprintf(text, sizeof(textbuf), fmt, args); |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 1477 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1478 | /* mark and strip a trailing newline */ |
Kay Sievers | c313af1 | 2012-05-14 20:46:27 +0200 | [diff] [blame] | 1479 | if (text_len && text[text_len-1] == '\n') { |
| 1480 | text_len--; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1481 | lflags |= LOG_NEWLINE; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1482 | } |
Kay Sievers | 9d90c8d | 2011-03-13 03:19:51 +0100 | [diff] [blame] | 1483 | |
Kay Sievers | c313af1 | 2012-05-14 20:46:27 +0200 | [diff] [blame] | 1484 | /* strip syslog prefix and extract log level or control flags */ |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1485 | if (text[0] == '<' && text[1] && text[2] == '>') { |
| 1486 | switch (text[1]) { |
| 1487 | case '0' ... '7': |
| 1488 | if (level == -1) |
| 1489 | level = text[1] - '0'; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1490 | case 'd': /* KERN_DEFAULT */ |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1491 | lflags |= LOG_PREFIX; |
Kay Sievers | 5c5d5ca | 2012-05-10 04:32:53 +0200 | [diff] [blame] | 1492 | case 'c': /* KERN_CONT */ |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1493 | text += 3; |
Kay Sievers | c313af1 | 2012-05-14 20:46:27 +0200 | [diff] [blame] | 1494 | text_len -= 3; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1495 | } |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1496 | } |
Nick Andrew | ac60ad7 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 1497 | |
Kay Sievers | c313af1 | 2012-05-14 20:46:27 +0200 | [diff] [blame] | 1498 | if (level == -1) |
| 1499 | level = default_message_loglevel; |
| 1500 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1501 | if (dict) |
| 1502 | lflags |= LOG_PREFIX|LOG_NEWLINE; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1503 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1504 | if (!(lflags & LOG_NEWLINE)) { |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1505 | /* |
| 1506 | * Flush the conflicting buffer. An earlier newline was missing, |
| 1507 | * or another task also prints continuation lines. |
| 1508 | */ |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1509 | if (cont.len && (lflags & LOG_PREFIX || cont.owner != current)) |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1510 | cont_flush(); |
Kay Sievers | c313af1 | 2012-05-14 20:46:27 +0200 | [diff] [blame] | 1511 | |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1512 | /* buffer line if possible, otherwise store it right away */ |
| 1513 | if (!cont_add(facility, level, text, text_len)) |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1514 | log_store(facility, level, lflags | LOG_CONT, 0, |
Kay Sievers | c313af1 | 2012-05-14 20:46:27 +0200 | [diff] [blame] | 1515 | dict, dictlen, text, text_len); |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1516 | } else { |
| 1517 | bool stored = false; |
| 1518 | |
| 1519 | /* |
Steven Rostedt | d362082 | 2012-06-29 11:40:11 -0400 | [diff] [blame] | 1520 | * If an earlier newline was missing and it was the same task, |
| 1521 | * either merge it with the current buffer and flush, or if |
| 1522 | * there was a race with interrupts (prefix == true) then just |
| 1523 | * flush it out and store this line separately. |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1524 | */ |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1525 | if (cont.len && cont.owner == current) { |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1526 | if (!(lflags & LOG_PREFIX)) |
Steven Rostedt | d362082 | 2012-06-29 11:40:11 -0400 | [diff] [blame] | 1527 | stored = cont_add(facility, level, text, text_len); |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1528 | cont_flush(); |
Kay Sievers | c313af1 | 2012-05-14 20:46:27 +0200 | [diff] [blame] | 1529 | } |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1530 | |
| 1531 | if (!stored) |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1532 | log_store(facility, level, lflags, 0, |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1533 | dict, dictlen, text, text_len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1534 | } |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1535 | printed_len += text_len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1536 | |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 1537 | /* |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1538 | * Try to acquire and then immediately release the console semaphore. |
| 1539 | * The release will print out buffers and wake up /dev/kmsg and syslog() |
| 1540 | * users. |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 1541 | * |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1542 | * The console_trylock_for_printk() function will release 'logbuf_lock' |
| 1543 | * regardless of whether it actually gets the console semaphore or not. |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 1544 | */ |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1545 | if (console_trylock_for_printk(this_cpu)) |
| 1546 | console_unlock(); |
Michael Ellerman | 76a8ad2 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 1547 | |
Linus Torvalds | 266c2e0 | 2008-03-24 19:25:08 -0700 | [diff] [blame] | 1548 | lockdep_on(); |
Ingo Molnar | 32a7600 | 2008-01-25 21:07:58 +0100 | [diff] [blame] | 1549 | out_restore_irqs: |
Peter Zijlstra | 1a9a8ae | 2011-06-07 11:17:30 +0200 | [diff] [blame] | 1550 | local_irq_restore(flags); |
Michael Ellerman | 76a8ad2 | 2006-06-25 05:47:40 -0700 | [diff] [blame] | 1551 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1552 | return printed_len; |
| 1553 | } |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1554 | EXPORT_SYMBOL(vprintk_emit); |
| 1555 | |
| 1556 | asmlinkage int vprintk(const char *fmt, va_list args) |
| 1557 | { |
| 1558 | return vprintk_emit(0, -1, NULL, 0, fmt, args); |
| 1559 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1560 | EXPORT_SYMBOL(vprintk); |
| 1561 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1562 | asmlinkage int printk_emit(int facility, int level, |
| 1563 | const char *dict, size_t dictlen, |
| 1564 | const char *fmt, ...) |
| 1565 | { |
| 1566 | va_list args; |
| 1567 | int r; |
| 1568 | |
| 1569 | va_start(args, fmt); |
| 1570 | r = vprintk_emit(facility, level, dict, dictlen, fmt, args); |
| 1571 | va_end(args); |
| 1572 | |
| 1573 | return r; |
| 1574 | } |
| 1575 | EXPORT_SYMBOL(printk_emit); |
| 1576 | |
| 1577 | /** |
| 1578 | * printk - print a kernel message |
| 1579 | * @fmt: format string |
| 1580 | * |
| 1581 | * This is printk(). It can be called from any context. We want it to work. |
| 1582 | * |
| 1583 | * We try to grab the console_lock. If we succeed, it's easy - we log the |
| 1584 | * output and call the console drivers. If we fail to get the semaphore, we |
| 1585 | * place the output into the log buffer and return. The current holder of |
| 1586 | * the console_sem will notice the new output in console_unlock(); and will |
| 1587 | * send it to the consoles before releasing the lock. |
| 1588 | * |
| 1589 | * One effect of this deferred printing is that code which calls printk() and |
| 1590 | * then changes console_loglevel may break. This is because console_loglevel |
| 1591 | * is inspected when the actual printing occurs. |
| 1592 | * |
| 1593 | * See also: |
| 1594 | * printf(3) |
| 1595 | * |
| 1596 | * See the vsnprintf() documentation for format string extensions over C99. |
| 1597 | */ |
| 1598 | asmlinkage int printk(const char *fmt, ...) |
| 1599 | { |
| 1600 | va_list args; |
| 1601 | int r; |
| 1602 | |
| 1603 | #ifdef CONFIG_KGDB_KDB |
| 1604 | if (unlikely(kdb_trap_printk)) { |
| 1605 | va_start(args, fmt); |
| 1606 | r = vkdb_printf(fmt, args); |
| 1607 | va_end(args); |
| 1608 | return r; |
| 1609 | } |
| 1610 | #endif |
| 1611 | va_start(args, fmt); |
| 1612 | r = vprintk_emit(0, -1, NULL, 0, fmt, args); |
| 1613 | va_end(args); |
| 1614 | |
| 1615 | return r; |
| 1616 | } |
| 1617 | EXPORT_SYMBOL(printk); |
Kay Sievers | 7f3a781 | 2012-05-09 01:37:51 +0200 | [diff] [blame] | 1618 | |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 1619 | #else |
| 1620 | |
Kay Sievers | 7f3a781 | 2012-05-09 01:37:51 +0200 | [diff] [blame] | 1621 | #define LOG_LINE_MAX 0 |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1622 | static struct cont { |
| 1623 | size_t len; |
| 1624 | size_t cons; |
| 1625 | u8 level; |
| 1626 | bool flushed:1; |
| 1627 | } cont; |
Kay Sievers | 7f3a781 | 2012-05-09 01:37:51 +0200 | [diff] [blame] | 1628 | static struct log *log_from_idx(u32 idx) { return NULL; } |
| 1629 | static u32 log_next(u32 idx) { return 0; } |
Kay Sievers | 7f3a781 | 2012-05-09 01:37:51 +0200 | [diff] [blame] | 1630 | static void call_console_drivers(int level, const char *text, size_t len) {} |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1631 | static size_t msg_print_text(const struct log *msg, enum log_flags prev, |
| 1632 | bool syslog, char *buf, size_t size) { return 0; } |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1633 | static size_t cont_print_text(char *text, size_t size) { return 0; } |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 1634 | |
Kay Sievers | 7f3a781 | 2012-05-09 01:37:51 +0200 | [diff] [blame] | 1635 | #endif /* CONFIG_PRINTK */ |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 1636 | |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1637 | static int __add_preferred_console(char *name, int idx, char *options, |
| 1638 | char *brl_options) |
| 1639 | { |
| 1640 | struct console_cmdline *c; |
| 1641 | int i; |
| 1642 | |
| 1643 | /* |
| 1644 | * See if this tty is not yet registered, and |
| 1645 | * if we have a slot free. |
| 1646 | */ |
| 1647 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) |
| 1648 | if (strcmp(console_cmdline[i].name, name) == 0 && |
| 1649 | console_cmdline[i].index == idx) { |
| 1650 | if (!brl_options) |
| 1651 | selected_console = i; |
| 1652 | return 0; |
| 1653 | } |
| 1654 | if (i == MAX_CMDLINECONSOLES) |
| 1655 | return -E2BIG; |
| 1656 | if (!brl_options) |
| 1657 | selected_console = i; |
| 1658 | c = &console_cmdline[i]; |
| 1659 | strlcpy(c->name, name, sizeof(c->name)); |
| 1660 | c->options = options; |
| 1661 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 1662 | c->brl_options = brl_options; |
| 1663 | #endif |
| 1664 | c->index = idx; |
| 1665 | return 0; |
| 1666 | } |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1667 | /* |
| 1668 | * Set up a list of consoles. Called from init/main.c |
| 1669 | */ |
| 1670 | static int __init console_setup(char *str) |
| 1671 | { |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1672 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1673 | char *s, *options, *brl_options = NULL; |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1674 | int idx; |
| 1675 | |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1676 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 1677 | if (!memcmp(str, "brl,", 4)) { |
| 1678 | brl_options = ""; |
| 1679 | str += 4; |
| 1680 | } else if (!memcmp(str, "brl=", 4)) { |
| 1681 | brl_options = str + 4; |
| 1682 | str = strchr(brl_options, ','); |
| 1683 | if (!str) { |
| 1684 | printk(KERN_ERR "need port name after brl=\n"); |
| 1685 | return 1; |
| 1686 | } |
| 1687 | *(str++) = 0; |
| 1688 | } |
| 1689 | #endif |
| 1690 | |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1691 | /* |
| 1692 | * Decode str into name, index, options. |
| 1693 | */ |
| 1694 | if (str[0] >= '0' && str[0] <= '9') { |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1695 | strcpy(buf, "ttyS"); |
| 1696 | strncpy(buf + 4, str, sizeof(buf) - 5); |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1697 | } else { |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1698 | strncpy(buf, str, sizeof(buf) - 1); |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1699 | } |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1700 | buf[sizeof(buf) - 1] = 0; |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1701 | if ((options = strchr(str, ',')) != NULL) |
| 1702 | *(options++) = 0; |
| 1703 | #ifdef __sparc__ |
| 1704 | if (!strcmp(str, "ttya")) |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1705 | strcpy(buf, "ttyS0"); |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1706 | if (!strcmp(str, "ttyb")) |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1707 | strcpy(buf, "ttyS1"); |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1708 | #endif |
Yinghai Lu | eaa944a | 2007-07-15 23:37:27 -0700 | [diff] [blame] | 1709 | for (s = buf; *s; s++) |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1710 | if ((*s >= '0' && *s <= '9') || *s == ',') |
| 1711 | break; |
| 1712 | idx = simple_strtoul(s, NULL, 10); |
| 1713 | *s = 0; |
| 1714 | |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1715 | __add_preferred_console(buf, idx, options, brl_options); |
Markus Armbruster | 9e124fe | 2008-05-26 23:31:07 +0100 | [diff] [blame] | 1716 | console_set_on_cmdline = 1; |
John Z. Bohach | 2ea1c53 | 2006-03-24 03:18:19 -0800 | [diff] [blame] | 1717 | return 1; |
| 1718 | } |
| 1719 | __setup("console=", console_setup); |
| 1720 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1721 | /** |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 1722 | * add_preferred_console - add a device to the list of preferred consoles. |
Martin Waitz | ddad86c | 2005-11-13 16:08:14 -0800 | [diff] [blame] | 1723 | * @name: device name |
| 1724 | * @idx: device index |
| 1725 | * @options: options for this console |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 1726 | * |
| 1727 | * The last preferred console added will be used for kernel messages |
| 1728 | * and stdin/out/err for init. Normally this is used by console_setup |
| 1729 | * above to handle user-supplied console arguments; however it can also |
| 1730 | * be used by arch-specific code either to override the user or more |
| 1731 | * commonly to provide a default console (ie from PROM variables) when |
| 1732 | * the user has not supplied one. |
| 1733 | */ |
David S. Miller | fb445ee | 2007-12-29 01:19:49 -0800 | [diff] [blame] | 1734 | int add_preferred_console(char *name, int idx, char *options) |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 1735 | { |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 1736 | return __add_preferred_console(name, idx, options, NULL); |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 1737 | } |
| 1738 | |
Daniel Ritz | b6b1d87 | 2007-08-03 16:07:43 +0200 | [diff] [blame] | 1739 | int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) |
Yinghai Lu | 18a8bd9 | 2007-07-15 23:37:59 -0700 | [diff] [blame] | 1740 | { |
| 1741 | struct console_cmdline *c; |
| 1742 | int i; |
| 1743 | |
| 1744 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) |
| 1745 | if (strcmp(console_cmdline[i].name, name) == 0 && |
| 1746 | console_cmdline[i].index == idx) { |
| 1747 | c = &console_cmdline[i]; |
Markus Armbruster | f735295 | 2008-04-30 00:54:52 -0700 | [diff] [blame] | 1748 | strlcpy(c->name, name_new, sizeof(c->name)); |
Yinghai Lu | 18a8bd9 | 2007-07-15 23:37:59 -0700 | [diff] [blame] | 1749 | c->name[sizeof(c->name) - 1] = 0; |
| 1750 | c->options = options; |
| 1751 | c->index = idx_new; |
| 1752 | return i; |
| 1753 | } |
| 1754 | /* not found */ |
| 1755 | return -1; |
| 1756 | } |
| 1757 | |
Rusty Russell | 2329abf | 2012-01-13 09:32:18 +1030 | [diff] [blame] | 1758 | bool console_suspend_enabled = 1; |
Andres Salomon | 8f4ce8c | 2007-10-18 03:04:50 -0700 | [diff] [blame] | 1759 | EXPORT_SYMBOL(console_suspend_enabled); |
| 1760 | |
| 1761 | static int __init console_suspend_disable(char *str) |
| 1762 | { |
| 1763 | console_suspend_enabled = 0; |
| 1764 | return 1; |
| 1765 | } |
| 1766 | __setup("no_console_suspend", console_suspend_disable); |
Yanmin Zhang | 134620f | 2011-10-31 17:11:27 -0700 | [diff] [blame] | 1767 | module_param_named(console_suspend, console_suspend_enabled, |
| 1768 | bool, S_IRUGO | S_IWUSR); |
| 1769 | MODULE_PARM_DESC(console_suspend, "suspend console during suspend" |
| 1770 | " and hibernate operations"); |
Andres Salomon | 8f4ce8c | 2007-10-18 03:04:50 -0700 | [diff] [blame] | 1771 | |
Matt Mackall | 3c0547b | 2005-05-16 21:53:47 -0700 | [diff] [blame] | 1772 | /** |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1773 | * suspend_console - suspend the console subsystem |
| 1774 | * |
| 1775 | * This disables printk() while we go into suspend states |
| 1776 | */ |
| 1777 | void suspend_console(void) |
| 1778 | { |
Andres Salomon | 8f4ce8c | 2007-10-18 03:04:50 -0700 | [diff] [blame] | 1779 | if (!console_suspend_enabled) |
| 1780 | return; |
Pavel Machek | 0d63081 | 2008-07-23 21:28:32 -0700 | [diff] [blame] | 1781 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1782 | console_lock(); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1783 | console_suspended = 1; |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1784 | up(&console_sem); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1785 | } |
| 1786 | |
| 1787 | void resume_console(void) |
| 1788 | { |
Andres Salomon | 8f4ce8c | 2007-10-18 03:04:50 -0700 | [diff] [blame] | 1789 | if (!console_suspend_enabled) |
| 1790 | return; |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1791 | down(&console_sem); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1792 | console_suspended = 0; |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1793 | console_unlock(); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1794 | } |
| 1795 | |
| 1796 | /** |
Kevin Cernekee | 034260d | 2010-06-03 22:11:25 -0700 | [diff] [blame] | 1797 | * console_cpu_notify - print deferred console messages after CPU hotplug |
| 1798 | * @self: notifier struct |
| 1799 | * @action: CPU hotplug event |
| 1800 | * @hcpu: unused |
| 1801 | * |
| 1802 | * If printk() is called from a CPU that is not online yet, the messages |
| 1803 | * will be spooled but will not show up on the console. This function is |
| 1804 | * called when a new CPU comes online (or fails to come up), and ensures |
| 1805 | * that any such output gets printed. |
| 1806 | */ |
| 1807 | static int __cpuinit console_cpu_notify(struct notifier_block *self, |
| 1808 | unsigned long action, void *hcpu) |
| 1809 | { |
| 1810 | switch (action) { |
| 1811 | case CPU_ONLINE: |
| 1812 | case CPU_DEAD: |
| 1813 | case CPU_DYING: |
| 1814 | case CPU_DOWN_FAILED: |
| 1815 | case CPU_UP_CANCELED: |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1816 | console_lock(); |
| 1817 | console_unlock(); |
Kevin Cernekee | 034260d | 2010-06-03 22:11:25 -0700 | [diff] [blame] | 1818 | } |
| 1819 | return NOTIFY_OK; |
| 1820 | } |
| 1821 | |
| 1822 | /** |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1823 | * console_lock - lock the console system for exclusive use. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1824 | * |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1825 | * Acquires a lock which guarantees that the caller has |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1826 | * exclusive access to the console system and the console_drivers list. |
| 1827 | * |
| 1828 | * Can sleep, returns nothing. |
| 1829 | */ |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1830 | void console_lock(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1831 | { |
Eric Sesterhenn | 8abd8e2 | 2006-04-01 01:21:17 +0200 | [diff] [blame] | 1832 | BUG_ON(in_interrupt()); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1833 | down(&console_sem); |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1834 | if (console_suspended) |
| 1835 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1836 | console_locked = 1; |
| 1837 | console_may_schedule = 1; |
| 1838 | } |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1839 | EXPORT_SYMBOL(console_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1840 | |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1841 | /** |
| 1842 | * console_trylock - try to lock the console system for exclusive use. |
| 1843 | * |
| 1844 | * Tried to acquire a lock which guarantees that the caller has |
| 1845 | * exclusive access to the console system and the console_drivers list. |
| 1846 | * |
| 1847 | * returns 1 on success, and 0 on failure to acquire the lock. |
| 1848 | */ |
| 1849 | int console_trylock(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1850 | { |
| 1851 | if (down_trylock(&console_sem)) |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1852 | return 0; |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1853 | if (console_suspended) { |
| 1854 | up(&console_sem); |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1855 | return 0; |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1856 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1857 | console_locked = 1; |
| 1858 | console_may_schedule = 0; |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1859 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1860 | } |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1861 | EXPORT_SYMBOL(console_trylock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1862 | |
| 1863 | int is_console_locked(void) |
| 1864 | { |
| 1865 | return console_locked; |
| 1866 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1867 | |
Peter Zijlstra | 3ccf3e8 | 2012-02-27 10:47:00 +0100 | [diff] [blame] | 1868 | /* |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1869 | * Delayed printk version, for scheduler-internal messages: |
Peter Zijlstra | 3ccf3e8 | 2012-02-27 10:47:00 +0100 | [diff] [blame] | 1870 | */ |
| 1871 | #define PRINTK_BUF_SIZE 512 |
| 1872 | |
| 1873 | #define PRINTK_PENDING_WAKEUP 0x01 |
| 1874 | #define PRINTK_PENDING_SCHED 0x02 |
| 1875 | |
Peter Zijlstra | b845b51 | 2008-08-08 21:47:09 +0200 | [diff] [blame] | 1876 | static DEFINE_PER_CPU(int, printk_pending); |
Peter Zijlstra | 3ccf3e8 | 2012-02-27 10:47:00 +0100 | [diff] [blame] | 1877 | static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf); |
Peter Zijlstra | b845b51 | 2008-08-08 21:47:09 +0200 | [diff] [blame] | 1878 | |
| 1879 | void printk_tick(void) |
| 1880 | { |
Eric Dumazet | 40dc11f | 2010-11-26 17:22:16 +0100 | [diff] [blame] | 1881 | if (__this_cpu_read(printk_pending)) { |
Peter Zijlstra | 3ccf3e8 | 2012-02-27 10:47:00 +0100 | [diff] [blame] | 1882 | int pending = __this_cpu_xchg(printk_pending, 0); |
| 1883 | if (pending & PRINTK_PENDING_SCHED) { |
| 1884 | char *buf = __get_cpu_var(printk_sched_buf); |
| 1885 | printk(KERN_WARNING "[sched_delayed] %s", buf); |
| 1886 | } |
| 1887 | if (pending & PRINTK_PENDING_WAKEUP) |
| 1888 | wake_up_interruptible(&log_wait); |
Peter Zijlstra | b845b51 | 2008-08-08 21:47:09 +0200 | [diff] [blame] | 1889 | } |
| 1890 | } |
| 1891 | |
| 1892 | int printk_needs_cpu(int cpu) |
| 1893 | { |
Eric Dumazet | 40dc11f | 2010-11-26 17:22:16 +0100 | [diff] [blame] | 1894 | if (cpu_is_offline(cpu)) |
Heiko Carstens | 61ab2544 | 2010-11-26 13:00:59 +0100 | [diff] [blame] | 1895 | printk_tick(); |
Eric Dumazet | 40dc11f | 2010-11-26 17:22:16 +0100 | [diff] [blame] | 1896 | return __this_cpu_read(printk_pending); |
Peter Zijlstra | b845b51 | 2008-08-08 21:47:09 +0200 | [diff] [blame] | 1897 | } |
| 1898 | |
Kirill Korotaev | e3e8a75 | 2007-02-10 01:46:19 -0800 | [diff] [blame] | 1899 | void wake_up_klogd(void) |
| 1900 | { |
Peter Zijlstra | b845b51 | 2008-08-08 21:47:09 +0200 | [diff] [blame] | 1901 | if (waitqueue_active(&log_wait)) |
Peter Zijlstra | 3ccf3e8 | 2012-02-27 10:47:00 +0100 | [diff] [blame] | 1902 | this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); |
Kirill Korotaev | e3e8a75 | 2007-02-10 01:46:19 -0800 | [diff] [blame] | 1903 | } |
| 1904 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1905 | /* the next printk record to write to the console */ |
| 1906 | static u64 console_seq; |
| 1907 | static u32 console_idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1908 | static enum log_flags console_prev; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1909 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1910 | /** |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1911 | * console_unlock - unlock the console system |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1912 | * |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1913 | * Releases the console_lock which the caller holds on the console system |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1914 | * and the console driver list. |
| 1915 | * |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1916 | * While the console_lock was held, console output may have been buffered |
| 1917 | * by printk(). If this is the case, console_unlock(); emits |
| 1918 | * the output prior to releasing the lock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1919 | * |
Kay Sievers | 7f3a781 | 2012-05-09 01:37:51 +0200 | [diff] [blame] | 1920 | * If there is output waiting, we wake /dev/kmsg and syslog() users. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1921 | * |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1922 | * console_unlock(); may be called from any context. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1923 | */ |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 1924 | void console_unlock(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1925 | { |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1926 | static char text[LOG_LINE_MAX]; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1927 | static u64 seen_seq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1928 | unsigned long flags; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1929 | bool wake_klogd = false; |
| 1930 | bool retry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1931 | |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1932 | if (console_suspended) { |
Arve Hjønnevåg | 403f307 | 2009-02-14 02:07:24 +0100 | [diff] [blame] | 1933 | up(&console_sem); |
Linus Torvalds | 557240b | 2006-06-19 18:16:01 -0700 | [diff] [blame] | 1934 | return; |
| 1935 | } |
Antonino A. Daplas | 78944e5 | 2006-08-05 12:14:16 -0700 | [diff] [blame] | 1936 | |
| 1937 | console_may_schedule = 0; |
| 1938 | |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1939 | /* flush buffered message fragment immediately to console */ |
| 1940 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
| 1941 | if (cont.len && (cont.cons < cont.len || cont.flushed)) { |
| 1942 | size_t len; |
| 1943 | |
| 1944 | len = cont_print_text(text, sizeof(text)); |
| 1945 | raw_spin_unlock(&logbuf_lock); |
| 1946 | stop_critical_timings(); |
| 1947 | call_console_drivers(cont.level, text, len); |
| 1948 | start_critical_timings(); |
| 1949 | local_irq_restore(flags); |
| 1950 | } else |
| 1951 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| 1952 | |
Peter Zijlstra | 4f2a8d3 | 2011-06-22 11:20:09 +0200 | [diff] [blame] | 1953 | again: |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1954 | for (;;) { |
| 1955 | struct log *msg; |
Kay Sievers | 3ce9a7c | 2012-05-13 23:30:46 +0200 | [diff] [blame] | 1956 | size_t len; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1957 | int level; |
| 1958 | |
Thomas Gleixner | 07354eb | 2009-07-25 17:50:36 +0200 | [diff] [blame] | 1959 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1960 | if (seen_seq != log_next_seq) { |
| 1961 | wake_klogd = true; |
| 1962 | seen_seq = log_next_seq; |
| 1963 | } |
| 1964 | |
| 1965 | if (console_seq < log_first_seq) { |
| 1966 | /* messages are gone, move to first one */ |
| 1967 | console_seq = log_first_seq; |
| 1968 | console_idx = log_first_idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1969 | console_prev = 0; |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1970 | } |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1971 | skip: |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1972 | if (console_seq == log_next_seq) |
| 1973 | break; |
| 1974 | |
| 1975 | msg = log_from_idx(console_idx); |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1976 | if (msg->flags & LOG_NOCONS) { |
| 1977 | /* |
| 1978 | * Skip record we have buffered and already printed |
| 1979 | * directly to the console when we received it. |
| 1980 | */ |
| 1981 | console_idx = log_next(console_idx); |
| 1982 | console_seq++; |
Kay Sievers | 68b6507 | 2012-07-06 09:50:09 -0700 | [diff] [blame] | 1983 | /* |
| 1984 | * We will get here again when we register a new |
| 1985 | * CON_PRINTBUFFER console. Clear the flag so we |
| 1986 | * will properly dump everything later. |
| 1987 | */ |
| 1988 | msg->flags &= ~LOG_NOCONS; |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1989 | goto skip; |
| 1990 | } |
Kay Sievers | 649e6ee | 2012-05-10 04:30:45 +0200 | [diff] [blame] | 1991 | |
Kay Sievers | 084681d | 2012-06-28 09:38:53 +0200 | [diff] [blame] | 1992 | level = msg->level; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1993 | len = msg_print_text(msg, console_prev, false, |
| 1994 | text, sizeof(text)); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1995 | console_idx = log_next(console_idx); |
| 1996 | console_seq++; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 1997 | console_prev = msg->flags; |
Thomas Gleixner | 07354eb | 2009-07-25 17:50:36 +0200 | [diff] [blame] | 1998 | raw_spin_unlock(&logbuf_lock); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 1999 | |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2000 | stop_critical_timings(); /* don't trace print latency */ |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 2001 | call_console_drivers(level, text, len); |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2002 | start_critical_timings(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2003 | local_irq_restore(flags); |
| 2004 | } |
| 2005 | console_locked = 0; |
Feng Tang | fe3d8ad | 2011-03-22 16:34:21 -0700 | [diff] [blame] | 2006 | |
| 2007 | /* Release the exclusive_console once it is used */ |
| 2008 | if (unlikely(exclusive_console)) |
| 2009 | exclusive_console = NULL; |
| 2010 | |
Thomas Gleixner | 07354eb | 2009-07-25 17:50:36 +0200 | [diff] [blame] | 2011 | raw_spin_unlock(&logbuf_lock); |
Peter Zijlstra | 4f2a8d3 | 2011-06-22 11:20:09 +0200 | [diff] [blame] | 2012 | |
Peter Zijlstra | 0b5e1c5 | 2011-06-07 11:15:33 +0200 | [diff] [blame] | 2013 | up(&console_sem); |
Peter Zijlstra | 4f2a8d3 | 2011-06-22 11:20:09 +0200 | [diff] [blame] | 2014 | |
| 2015 | /* |
| 2016 | * Someone could have filled up the buffer again, so re-check if there's |
| 2017 | * something to flush. In case we cannot trylock the console_sem again, |
| 2018 | * there's a new owner and the console_unlock() from them will do the |
| 2019 | * flush, no worries. |
| 2020 | */ |
Thomas Gleixner | 07354eb | 2009-07-25 17:50:36 +0200 | [diff] [blame] | 2021 | raw_spin_lock(&logbuf_lock); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 2022 | retry = console_seq != log_next_seq; |
Peter Zijlstra | 09dc3cf | 2011-12-08 14:34:13 -0800 | [diff] [blame] | 2023 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| 2024 | |
Peter Zijlstra | 4f2a8d3 | 2011-06-22 11:20:09 +0200 | [diff] [blame] | 2025 | if (retry && console_trylock()) |
| 2026 | goto again; |
| 2027 | |
Kirill Korotaev | e3e8a75 | 2007-02-10 01:46:19 -0800 | [diff] [blame] | 2028 | if (wake_klogd) |
| 2029 | wake_up_klogd(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2030 | } |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2031 | EXPORT_SYMBOL(console_unlock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2032 | |
Martin Waitz | ddad86c | 2005-11-13 16:08:14 -0800 | [diff] [blame] | 2033 | /** |
| 2034 | * console_conditional_schedule - yield the CPU if required |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2035 | * |
| 2036 | * If the console code is currently allowed to sleep, and |
| 2037 | * if this CPU should yield the CPU to another task, do |
| 2038 | * so here. |
| 2039 | * |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2040 | * Must be called within console_lock();. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2041 | */ |
| 2042 | void __sched console_conditional_schedule(void) |
| 2043 | { |
| 2044 | if (console_may_schedule) |
| 2045 | cond_resched(); |
| 2046 | } |
| 2047 | EXPORT_SYMBOL(console_conditional_schedule); |
| 2048 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2049 | void console_unblank(void) |
| 2050 | { |
| 2051 | struct console *c; |
| 2052 | |
| 2053 | /* |
| 2054 | * console_unblank can no longer be called in interrupt context unless |
| 2055 | * oops_in_progress is set to 1.. |
| 2056 | */ |
| 2057 | if (oops_in_progress) { |
| 2058 | if (down_trylock(&console_sem) != 0) |
| 2059 | return; |
| 2060 | } else |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2061 | console_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2062 | |
| 2063 | console_locked = 1; |
| 2064 | console_may_schedule = 0; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2065 | for_each_console(c) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2066 | if ((c->flags & CON_ENABLED) && c->unblank) |
| 2067 | c->unblank(); |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2068 | console_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2069 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2070 | |
| 2071 | /* |
| 2072 | * Return the console tty driver structure and its associated index |
| 2073 | */ |
| 2074 | struct tty_driver *console_device(int *index) |
| 2075 | { |
| 2076 | struct console *c; |
| 2077 | struct tty_driver *driver = NULL; |
| 2078 | |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2079 | console_lock(); |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2080 | for_each_console(c) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2081 | if (!c->device) |
| 2082 | continue; |
| 2083 | driver = c->device(c, index); |
| 2084 | if (driver) |
| 2085 | break; |
| 2086 | } |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2087 | console_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2088 | return driver; |
| 2089 | } |
| 2090 | |
| 2091 | /* |
| 2092 | * Prevent further output on the passed console device so that (for example) |
| 2093 | * serial drivers can disable console output before suspending a port, and can |
| 2094 | * re-enable output afterwards. |
| 2095 | */ |
| 2096 | void console_stop(struct console *console) |
| 2097 | { |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2098 | console_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2099 | console->flags &= ~CON_ENABLED; |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2100 | console_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2101 | } |
| 2102 | EXPORT_SYMBOL(console_stop); |
| 2103 | |
| 2104 | void console_start(struct console *console) |
| 2105 | { |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2106 | console_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2107 | console->flags |= CON_ENABLED; |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2108 | console_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2109 | } |
| 2110 | EXPORT_SYMBOL(console_start); |
| 2111 | |
Fabio M. Di Nitto | 7bf6939 | 2011-03-22 16:34:20 -0700 | [diff] [blame] | 2112 | static int __read_mostly keep_bootcon; |
| 2113 | |
| 2114 | static int __init keep_bootcon_setup(char *str) |
| 2115 | { |
| 2116 | keep_bootcon = 1; |
| 2117 | printk(KERN_INFO "debug: skip boot console de-registration.\n"); |
| 2118 | |
| 2119 | return 0; |
| 2120 | } |
| 2121 | |
| 2122 | early_param("keep_bootcon", keep_bootcon_setup); |
| 2123 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2124 | /* |
| 2125 | * The console driver calls this routine during kernel initialization |
| 2126 | * to register the console printing procedure with printk() and to |
| 2127 | * print any messages that were printed by the kernel before the |
| 2128 | * console driver was initialized. |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2129 | * |
| 2130 | * This can happen pretty early during the boot process (because of |
| 2131 | * early_printk) - sometimes before setup_arch() completes - be careful |
| 2132 | * of what kernel features are used - they may not be initialised yet. |
| 2133 | * |
| 2134 | * There are two types of consoles - bootconsoles (early_printk) and |
| 2135 | * "real" consoles (everything which is not a bootconsole) which are |
| 2136 | * handled differently. |
| 2137 | * - Any number of bootconsoles can be registered at any time. |
| 2138 | * - As soon as a "real" console is registered, all bootconsoles |
| 2139 | * will be unregistered automatically. |
| 2140 | * - Once a "real" console is registered, any attempt to register a |
| 2141 | * bootconsoles will be rejected |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2142 | */ |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2143 | void register_console(struct console *newcon) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2144 | { |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 2145 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2146 | unsigned long flags; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2147 | struct console *bcon = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2148 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2149 | /* |
| 2150 | * before we register a new CON_BOOT console, make sure we don't |
| 2151 | * already have a valid console |
| 2152 | */ |
| 2153 | if (console_drivers && newcon->flags & CON_BOOT) { |
| 2154 | /* find the last or real console */ |
| 2155 | for_each_console(bcon) { |
| 2156 | if (!(bcon->flags & CON_BOOT)) { |
| 2157 | printk(KERN_INFO "Too late to register bootconsole %s%d\n", |
| 2158 | newcon->name, newcon->index); |
| 2159 | return; |
| 2160 | } |
| 2161 | } |
Gerd Hoffmann | 69331af | 2007-05-08 00:26:49 -0700 | [diff] [blame] | 2162 | } |
| 2163 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2164 | if (console_drivers && console_drivers->flags & CON_BOOT) |
| 2165 | bcon = console_drivers; |
| 2166 | |
| 2167 | if (preferred_console < 0 || bcon || !console_drivers) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2168 | preferred_console = selected_console; |
| 2169 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2170 | if (newcon->early_setup) |
| 2171 | newcon->early_setup(); |
Yinghai Lu | 18a8bd9 | 2007-07-15 23:37:59 -0700 | [diff] [blame] | 2172 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2173 | /* |
| 2174 | * See if we want to use this console driver. If we |
| 2175 | * didn't select a console we take the first one |
| 2176 | * that registers here. |
| 2177 | */ |
| 2178 | if (preferred_console < 0) { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2179 | if (newcon->index < 0) |
| 2180 | newcon->index = 0; |
| 2181 | if (newcon->setup == NULL || |
| 2182 | newcon->setup(newcon, NULL) == 0) { |
| 2183 | newcon->flags |= CON_ENABLED; |
| 2184 | if (newcon->device) { |
| 2185 | newcon->flags |= CON_CONSDEV; |
Jan Kiszka | cd3a1b8 | 2008-05-12 21:21:04 +0200 | [diff] [blame] | 2186 | preferred_console = 0; |
| 2187 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2188 | } |
| 2189 | } |
| 2190 | |
| 2191 | /* |
| 2192 | * See if this console matches one we selected on |
| 2193 | * the command line. |
| 2194 | */ |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 2195 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; |
| 2196 | i++) { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2197 | if (strcmp(console_cmdline[i].name, newcon->name) != 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2198 | continue; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2199 | if (newcon->index >= 0 && |
| 2200 | newcon->index != console_cmdline[i].index) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2201 | continue; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2202 | if (newcon->index < 0) |
| 2203 | newcon->index = console_cmdline[i].index; |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 2204 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 2205 | if (console_cmdline[i].brl_options) { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2206 | newcon->flags |= CON_BRL; |
| 2207 | braille_register_console(newcon, |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 2208 | console_cmdline[i].index, |
| 2209 | console_cmdline[i].options, |
| 2210 | console_cmdline[i].brl_options); |
| 2211 | return; |
| 2212 | } |
| 2213 | #endif |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2214 | if (newcon->setup && |
| 2215 | newcon->setup(newcon, console_cmdline[i].options) != 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2216 | break; |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2217 | newcon->flags |= CON_ENABLED; |
| 2218 | newcon->index = console_cmdline[i].index; |
Greg Edwards | ab4af03 | 2005-06-23 00:09:05 -0700 | [diff] [blame] | 2219 | if (i == selected_console) { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2220 | newcon->flags |= CON_CONSDEV; |
Greg Edwards | ab4af03 | 2005-06-23 00:09:05 -0700 | [diff] [blame] | 2221 | preferred_console = selected_console; |
| 2222 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2223 | break; |
| 2224 | } |
| 2225 | |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2226 | if (!(newcon->flags & CON_ENABLED)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2227 | return; |
| 2228 | |
Robin Getz | 8259cf4 | 2009-07-09 13:08:37 -0400 | [diff] [blame] | 2229 | /* |
| 2230 | * If we have a bootconsole, and are switching to a real console, |
| 2231 | * don't print everything out again, since when the boot console, and |
| 2232 | * the real console are the same physical device, it's annoying to |
| 2233 | * see the beginning boot messages twice |
| 2234 | */ |
| 2235 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2236 | newcon->flags &= ~CON_PRINTBUFFER; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2237 | |
| 2238 | /* |
| 2239 | * Put this console in the list - keep the |
| 2240 | * preferred driver at the head of the list. |
| 2241 | */ |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2242 | console_lock(); |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2243 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
| 2244 | newcon->next = console_drivers; |
| 2245 | console_drivers = newcon; |
| 2246 | if (newcon->next) |
| 2247 | newcon->next->flags &= ~CON_CONSDEV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2248 | } else { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2249 | newcon->next = console_drivers->next; |
| 2250 | console_drivers->next = newcon; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2251 | } |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2252 | if (newcon->flags & CON_PRINTBUFFER) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2253 | /* |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2254 | * console_unlock(); will print out the buffered messages |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2255 | * for us. |
| 2256 | */ |
Thomas Gleixner | 07354eb | 2009-07-25 17:50:36 +0200 | [diff] [blame] | 2257 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 2258 | console_seq = syslog_seq; |
| 2259 | console_idx = syslog_idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 2260 | console_prev = syslog_prev; |
Thomas Gleixner | 07354eb | 2009-07-25 17:50:36 +0200 | [diff] [blame] | 2261 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
Feng Tang | fe3d8ad | 2011-03-22 16:34:21 -0700 | [diff] [blame] | 2262 | /* |
| 2263 | * We're about to replay the log buffer. Only do this to the |
| 2264 | * just-registered console to avoid excessive message spam to |
| 2265 | * the already-registered consoles. |
| 2266 | */ |
| 2267 | exclusive_console = newcon; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2268 | } |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2269 | console_unlock(); |
Kay Sievers | fbc92a3 | 2010-12-01 18:51:05 +0100 | [diff] [blame] | 2270 | console_sysfs_notify(); |
Robin Getz | 8259cf4 | 2009-07-09 13:08:37 -0400 | [diff] [blame] | 2271 | |
| 2272 | /* |
| 2273 | * By unregistering the bootconsoles after we enable the real console |
| 2274 | * we get the "console xxx enabled" message on all the consoles - |
| 2275 | * boot consoles, real consoles, etc - this is to ensure that end |
| 2276 | * users know there might be something in the kernel's log buffer that |
| 2277 | * went to the bootconsole (that they do not see on the real console) |
| 2278 | */ |
Fabio M. Di Nitto | 7bf6939 | 2011-03-22 16:34:20 -0700 | [diff] [blame] | 2279 | if (bcon && |
| 2280 | ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && |
| 2281 | !keep_bootcon) { |
Robin Getz | 8259cf4 | 2009-07-09 13:08:37 -0400 | [diff] [blame] | 2282 | /* we need to iterate through twice, to make sure we print |
| 2283 | * everything out, before we unregister the console(s) |
| 2284 | */ |
| 2285 | printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n", |
| 2286 | newcon->name, newcon->index); |
| 2287 | for_each_console(bcon) |
| 2288 | if (bcon->flags & CON_BOOT) |
| 2289 | unregister_console(bcon); |
| 2290 | } else { |
| 2291 | printk(KERN_INFO "%sconsole [%s%d] enabled\n", |
| 2292 | (newcon->flags & CON_BOOT) ? "boot" : "" , |
| 2293 | newcon->name, newcon->index); |
| 2294 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2295 | } |
| 2296 | EXPORT_SYMBOL(register_console); |
| 2297 | |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 2298 | int unregister_console(struct console *console) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2299 | { |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 2300 | struct console *a, *b; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2301 | int res = 1; |
| 2302 | |
Samuel Thibault | f7511d5 | 2008-04-30 00:54:51 -0700 | [diff] [blame] | 2303 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
| 2304 | if (console->flags & CON_BRL) |
| 2305 | return braille_unregister_console(console); |
| 2306 | #endif |
| 2307 | |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2308 | console_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2309 | if (console_drivers == console) { |
| 2310 | console_drivers=console->next; |
| 2311 | res = 0; |
Benjamin Herrenschmidt | e9b15b5 | 2005-11-23 13:37:44 -0800 | [diff] [blame] | 2312 | } else if (console_drivers) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2313 | for (a=console_drivers->next, b=console_drivers ; |
| 2314 | a; b=a, a=b->next) { |
| 2315 | if (a == console) { |
| 2316 | b->next = a->next; |
| 2317 | res = 0; |
| 2318 | break; |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 2319 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2320 | } |
| 2321 | } |
Jesper Juhl | 40dc565 | 2005-10-30 15:02:46 -0800 | [diff] [blame] | 2322 | |
Gerd Hoffmann | 69331af | 2007-05-08 00:26:49 -0700 | [diff] [blame] | 2323 | /* |
Greg Edwards | ab4af03 | 2005-06-23 00:09:05 -0700 | [diff] [blame] | 2324 | * If this isn't the last console and it has CON_CONSDEV set, we |
| 2325 | * need to set it on the next preferred console. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2326 | */ |
Gerd Hoffmann | 69331af | 2007-05-08 00:26:49 -0700 | [diff] [blame] | 2327 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
Greg Edwards | ab4af03 | 2005-06-23 00:09:05 -0700 | [diff] [blame] | 2328 | console_drivers->flags |= CON_CONSDEV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2329 | |
Torben Hohn | ac751ef | 2011-01-25 15:07:35 -0800 | [diff] [blame] | 2330 | console_unlock(); |
Kay Sievers | fbc92a3 | 2010-12-01 18:51:05 +0100 | [diff] [blame] | 2331 | console_sysfs_notify(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2332 | return res; |
| 2333 | } |
| 2334 | EXPORT_SYMBOL(unregister_console); |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 2335 | |
Kevin Cernekee | 034260d | 2010-06-03 22:11:25 -0700 | [diff] [blame] | 2336 | static int __init printk_late_init(void) |
Robin Getz | 0c5564b | 2007-08-20 15:22:47 -0400 | [diff] [blame] | 2337 | { |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2338 | struct console *con; |
| 2339 | |
| 2340 | for_each_console(con) { |
Nishanth Aravamudan | 4c30c6f | 2011-08-25 15:59:11 -0700 | [diff] [blame] | 2341 | if (!keep_bootcon && con->flags & CON_BOOT) { |
Robin Getz | cb00e99 | 2007-08-21 23:14:58 -0400 | [diff] [blame] | 2342 | printk(KERN_INFO "turn off boot console %s%d\n", |
Robin Getz | 4d09161 | 2009-07-01 21:08:37 -0400 | [diff] [blame] | 2343 | con->name, con->index); |
Sonic Zhang | 42c2c8c | 2009-08-06 15:58:11 -0700 | [diff] [blame] | 2344 | unregister_console(con); |
Robin Getz | cb00e99 | 2007-08-21 23:14:58 -0400 | [diff] [blame] | 2345 | } |
Robin Getz | 0c5564b | 2007-08-20 15:22:47 -0400 | [diff] [blame] | 2346 | } |
Kevin Cernekee | 034260d | 2010-06-03 22:11:25 -0700 | [diff] [blame] | 2347 | hotcpu_notifier(console_cpu_notify, 0); |
Robin Getz | 0c5564b | 2007-08-20 15:22:47 -0400 | [diff] [blame] | 2348 | return 0; |
| 2349 | } |
Kevin Cernekee | 034260d | 2010-06-03 22:11:25 -0700 | [diff] [blame] | 2350 | late_initcall(printk_late_init); |
Robin Getz | 0c5564b | 2007-08-20 15:22:47 -0400 | [diff] [blame] | 2351 | |
Joe Perches | 7ef3d2f | 2008-02-08 04:21:25 -0800 | [diff] [blame] | 2352 | #if defined CONFIG_PRINTK |
Dave Young | 717115e | 2008-07-25 01:45:58 -0700 | [diff] [blame] | 2353 | |
Peter Zijlstra | 600e145 | 2012-03-15 12:35:37 +0100 | [diff] [blame] | 2354 | int printk_sched(const char *fmt, ...) |
| 2355 | { |
| 2356 | unsigned long flags; |
| 2357 | va_list args; |
| 2358 | char *buf; |
| 2359 | int r; |
| 2360 | |
| 2361 | local_irq_save(flags); |
| 2362 | buf = __get_cpu_var(printk_sched_buf); |
| 2363 | |
| 2364 | va_start(args, fmt); |
| 2365 | r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args); |
| 2366 | va_end(args); |
| 2367 | |
| 2368 | __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED); |
| 2369 | local_irq_restore(flags); |
| 2370 | |
| 2371 | return r; |
| 2372 | } |
| 2373 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2374 | /* |
| 2375 | * printk rate limiting, lifted from the networking subsystem. |
| 2376 | * |
Uwe Kleine-König | 641de9d | 2008-07-29 22:33:38 -0700 | [diff] [blame] | 2377 | * This enforces a rate limit: not more than 10 kernel messages |
| 2378 | * every 5s to make a denial-of-service attack impossible. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2379 | */ |
Uwe Kleine-König | 641de9d | 2008-07-29 22:33:38 -0700 | [diff] [blame] | 2380 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
| 2381 | |
Christian Borntraeger | 5c82871 | 2009-10-23 14:58:11 +0200 | [diff] [blame] | 2382 | int __printk_ratelimit(const char *func) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2383 | { |
Christian Borntraeger | 5c82871 | 2009-10-23 14:58:11 +0200 | [diff] [blame] | 2384 | return ___ratelimit(&printk_ratelimit_state, func); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2385 | } |
Christian Borntraeger | 5c82871 | 2009-10-23 14:58:11 +0200 | [diff] [blame] | 2386 | EXPORT_SYMBOL(__printk_ratelimit); |
Andrew Morton | f46c483 | 2006-11-02 22:07:16 -0800 | [diff] [blame] | 2387 | |
| 2388 | /** |
| 2389 | * printk_timed_ratelimit - caller-controlled printk ratelimiting |
| 2390 | * @caller_jiffies: pointer to caller's state |
| 2391 | * @interval_msecs: minimum interval between prints |
| 2392 | * |
| 2393 | * printk_timed_ratelimit() returns true if more than @interval_msecs |
| 2394 | * milliseconds have elapsed since the last time printk_timed_ratelimit() |
| 2395 | * returned true. |
| 2396 | */ |
| 2397 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, |
| 2398 | unsigned int interval_msecs) |
| 2399 | { |
Guillaume Knispel | f2d28a2 | 2009-03-17 16:18:42 +0100 | [diff] [blame] | 2400 | if (*caller_jiffies == 0 |
| 2401 | || !time_in_range(jiffies, *caller_jiffies, |
| 2402 | *caller_jiffies |
| 2403 | + msecs_to_jiffies(interval_msecs))) { |
| 2404 | *caller_jiffies = jiffies; |
Andrew Morton | f46c483 | 2006-11-02 22:07:16 -0800 | [diff] [blame] | 2405 | return true; |
| 2406 | } |
| 2407 | return false; |
| 2408 | } |
| 2409 | EXPORT_SYMBOL(printk_timed_ratelimit); |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 2410 | |
| 2411 | static DEFINE_SPINLOCK(dump_list_lock); |
| 2412 | static LIST_HEAD(dump_list); |
| 2413 | |
| 2414 | /** |
| 2415 | * kmsg_dump_register - register a kernel log dumper. |
Randy Dunlap | 6485536 | 2009-12-17 15:27:27 -0800 | [diff] [blame] | 2416 | * @dumper: pointer to the kmsg_dumper structure |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 2417 | * |
| 2418 | * Adds a kernel log dumper to the system. The dump callback in the |
| 2419 | * structure will be called when the kernel oopses or panics and must be |
| 2420 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. |
| 2421 | */ |
| 2422 | int kmsg_dump_register(struct kmsg_dumper *dumper) |
| 2423 | { |
| 2424 | unsigned long flags; |
| 2425 | int err = -EBUSY; |
| 2426 | |
| 2427 | /* The dump callback needs to be set */ |
| 2428 | if (!dumper->dump) |
| 2429 | return -EINVAL; |
| 2430 | |
| 2431 | spin_lock_irqsave(&dump_list_lock, flags); |
| 2432 | /* Don't allow registering multiple times */ |
| 2433 | if (!dumper->registered) { |
| 2434 | dumper->registered = 1; |
Huang Ying | fb842b0 | 2011-01-12 16:59:43 -0800 | [diff] [blame] | 2435 | list_add_tail_rcu(&dumper->list, &dump_list); |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 2436 | err = 0; |
| 2437 | } |
| 2438 | spin_unlock_irqrestore(&dump_list_lock, flags); |
| 2439 | |
| 2440 | return err; |
| 2441 | } |
| 2442 | EXPORT_SYMBOL_GPL(kmsg_dump_register); |
| 2443 | |
| 2444 | /** |
| 2445 | * kmsg_dump_unregister - unregister a kmsg dumper. |
Randy Dunlap | 6485536 | 2009-12-17 15:27:27 -0800 | [diff] [blame] | 2446 | * @dumper: pointer to the kmsg_dumper structure |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 2447 | * |
| 2448 | * Removes a dump device from the system. Returns zero on success and |
| 2449 | * %-EINVAL otherwise. |
| 2450 | */ |
| 2451 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) |
| 2452 | { |
| 2453 | unsigned long flags; |
| 2454 | int err = -EINVAL; |
| 2455 | |
| 2456 | spin_lock_irqsave(&dump_list_lock, flags); |
| 2457 | if (dumper->registered) { |
| 2458 | dumper->registered = 0; |
Huang Ying | fb842b0 | 2011-01-12 16:59:43 -0800 | [diff] [blame] | 2459 | list_del_rcu(&dumper->list); |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 2460 | err = 0; |
| 2461 | } |
| 2462 | spin_unlock_irqrestore(&dump_list_lock, flags); |
Huang Ying | fb842b0 | 2011-01-12 16:59:43 -0800 | [diff] [blame] | 2463 | synchronize_rcu(); |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 2464 | |
| 2465 | return err; |
| 2466 | } |
| 2467 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); |
| 2468 | |
Kay Sievers | 7ff9554 | 2012-05-03 02:29:13 +0200 | [diff] [blame] | 2469 | static bool always_kmsg_dump; |
| 2470 | module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); |
| 2471 | |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 2472 | /** |
| 2473 | * kmsg_dump - dump kernel log to kernel message dumpers. |
| 2474 | * @reason: the reason (oops, panic etc) for dumping |
| 2475 | * |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2476 | * Call each of the registered dumper's dump() callback, which can |
| 2477 | * retrieve the kmsg records with kmsg_dump_get_line() or |
| 2478 | * kmsg_dump_get_buffer(). |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 2479 | */ |
| 2480 | void kmsg_dump(enum kmsg_dump_reason reason) |
| 2481 | { |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 2482 | struct kmsg_dumper *dumper; |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 2483 | unsigned long flags; |
| 2484 | |
Matthew Garrett | c22ab33 | 2012-03-05 14:59:10 -0800 | [diff] [blame] | 2485 | if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
| 2486 | return; |
| 2487 | |
Huang Ying | fb842b0 | 2011-01-12 16:59:43 -0800 | [diff] [blame] | 2488 | rcu_read_lock(); |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2489 | list_for_each_entry_rcu(dumper, &dump_list, list) { |
| 2490 | if (dumper->max_reason && reason > dumper->max_reason) |
| 2491 | continue; |
| 2492 | |
| 2493 | /* initialize iterator with data about the stored records */ |
| 2494 | dumper->active = true; |
| 2495 | |
| 2496 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
| 2497 | dumper->cur_seq = clear_seq; |
| 2498 | dumper->cur_idx = clear_idx; |
| 2499 | dumper->next_seq = log_next_seq; |
| 2500 | dumper->next_idx = log_next_idx; |
| 2501 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| 2502 | |
| 2503 | /* invoke dumper which will iterate over records */ |
| 2504 | dumper->dump(dumper, reason); |
| 2505 | |
| 2506 | /* reset iterator */ |
| 2507 | dumper->active = false; |
| 2508 | } |
Huang Ying | fb842b0 | 2011-01-12 16:59:43 -0800 | [diff] [blame] | 2509 | rcu_read_unlock(); |
Simon Kagstrom | 456b565 | 2009-10-16 14:09:18 +0200 | [diff] [blame] | 2510 | } |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2511 | |
| 2512 | /** |
Anton Vorontsov | 533827c | 2012-07-20 17:28:07 -0700 | [diff] [blame] | 2513 | * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) |
| 2514 | * @dumper: registered kmsg dumper |
| 2515 | * @syslog: include the "<4>" prefixes |
| 2516 | * @line: buffer to copy the line to |
| 2517 | * @size: maximum size of the buffer |
| 2518 | * @len: length of line placed into buffer |
| 2519 | * |
| 2520 | * Start at the beginning of the kmsg buffer, with the oldest kmsg |
| 2521 | * record, and copy one record into the provided buffer. |
| 2522 | * |
| 2523 | * Consecutive calls will return the next available record moving |
| 2524 | * towards the end of the buffer with the youngest messages. |
| 2525 | * |
| 2526 | * A return value of FALSE indicates that there are no more records to |
| 2527 | * read. |
| 2528 | * |
| 2529 | * The function is similar to kmsg_dump_get_line(), but grabs no locks. |
| 2530 | */ |
| 2531 | bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, |
| 2532 | char *line, size_t size, size_t *len) |
| 2533 | { |
| 2534 | struct log *msg; |
| 2535 | size_t l = 0; |
| 2536 | bool ret = false; |
| 2537 | |
| 2538 | if (!dumper->active) |
| 2539 | goto out; |
| 2540 | |
| 2541 | if (dumper->cur_seq < log_first_seq) { |
| 2542 | /* messages are gone, move to first available one */ |
| 2543 | dumper->cur_seq = log_first_seq; |
| 2544 | dumper->cur_idx = log_first_idx; |
| 2545 | } |
| 2546 | |
| 2547 | /* last entry */ |
| 2548 | if (dumper->cur_seq >= log_next_seq) |
| 2549 | goto out; |
| 2550 | |
| 2551 | msg = log_from_idx(dumper->cur_idx); |
| 2552 | l = msg_print_text(msg, 0, syslog, line, size); |
| 2553 | |
| 2554 | dumper->cur_idx = log_next(dumper->cur_idx); |
| 2555 | dumper->cur_seq++; |
| 2556 | ret = true; |
| 2557 | out: |
| 2558 | if (len) |
| 2559 | *len = l; |
| 2560 | return ret; |
| 2561 | } |
| 2562 | |
| 2563 | /** |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2564 | * kmsg_dump_get_line - retrieve one kmsg log line |
| 2565 | * @dumper: registered kmsg dumper |
| 2566 | * @syslog: include the "<4>" prefixes |
| 2567 | * @line: buffer to copy the line to |
| 2568 | * @size: maximum size of the buffer |
| 2569 | * @len: length of line placed into buffer |
| 2570 | * |
| 2571 | * Start at the beginning of the kmsg buffer, with the oldest kmsg |
| 2572 | * record, and copy one record into the provided buffer. |
| 2573 | * |
| 2574 | * Consecutive calls will return the next available record moving |
| 2575 | * towards the end of the buffer with the youngest messages. |
| 2576 | * |
| 2577 | * A return value of FALSE indicates that there are no more records to |
| 2578 | * read. |
| 2579 | */ |
| 2580 | bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, |
| 2581 | char *line, size_t size, size_t *len) |
| 2582 | { |
| 2583 | unsigned long flags; |
Anton Vorontsov | 533827c | 2012-07-20 17:28:07 -0700 | [diff] [blame] | 2584 | bool ret; |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2585 | |
| 2586 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
Anton Vorontsov | 533827c | 2012-07-20 17:28:07 -0700 | [diff] [blame] | 2587 | ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2588 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
Anton Vorontsov | 533827c | 2012-07-20 17:28:07 -0700 | [diff] [blame] | 2589 | |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2590 | return ret; |
| 2591 | } |
| 2592 | EXPORT_SYMBOL_GPL(kmsg_dump_get_line); |
| 2593 | |
| 2594 | /** |
| 2595 | * kmsg_dump_get_buffer - copy kmsg log lines |
| 2596 | * @dumper: registered kmsg dumper |
| 2597 | * @syslog: include the "<4>" prefixes |
Randy Dunlap | 4f0f4af | 2012-06-30 15:37:24 -0700 | [diff] [blame] | 2598 | * @buf: buffer to copy the line to |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2599 | * @size: maximum size of the buffer |
| 2600 | * @len: length of line placed into buffer |
| 2601 | * |
| 2602 | * Start at the end of the kmsg buffer and fill the provided buffer |
| 2603 | * with as many of the the *youngest* kmsg records that fit into it. |
| 2604 | * If the buffer is large enough, all available kmsg records will be |
| 2605 | * copied with a single call. |
| 2606 | * |
| 2607 | * Consecutive calls will fill the buffer with the next block of |
| 2608 | * available older records, not including the earlier retrieved ones. |
| 2609 | * |
| 2610 | * A return value of FALSE indicates that there are no more records to |
| 2611 | * read. |
| 2612 | */ |
| 2613 | bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, |
| 2614 | char *buf, size_t size, size_t *len) |
| 2615 | { |
| 2616 | unsigned long flags; |
| 2617 | u64 seq; |
| 2618 | u32 idx; |
| 2619 | u64 next_seq; |
| 2620 | u32 next_idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 2621 | enum log_flags prev; |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2622 | size_t l = 0; |
| 2623 | bool ret = false; |
| 2624 | |
| 2625 | if (!dumper->active) |
| 2626 | goto out; |
| 2627 | |
| 2628 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
| 2629 | if (dumper->cur_seq < log_first_seq) { |
| 2630 | /* messages are gone, move to first available one */ |
| 2631 | dumper->cur_seq = log_first_seq; |
| 2632 | dumper->cur_idx = log_first_idx; |
| 2633 | } |
| 2634 | |
| 2635 | /* last entry */ |
| 2636 | if (dumper->cur_seq >= dumper->next_seq) { |
| 2637 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| 2638 | goto out; |
| 2639 | } |
| 2640 | |
| 2641 | /* calculate length of entire buffer */ |
| 2642 | seq = dumper->cur_seq; |
| 2643 | idx = dumper->cur_idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 2644 | prev = 0; |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2645 | while (seq < dumper->next_seq) { |
| 2646 | struct log *msg = log_from_idx(idx); |
| 2647 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 2648 | l += msg_print_text(msg, prev, true, NULL, 0); |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2649 | idx = log_next(idx); |
| 2650 | seq++; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 2651 | prev = msg->flags; |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2652 | } |
| 2653 | |
| 2654 | /* move first record forward until length fits into the buffer */ |
| 2655 | seq = dumper->cur_seq; |
| 2656 | idx = dumper->cur_idx; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 2657 | prev = 0; |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2658 | while (l > size && seq < dumper->next_seq) { |
| 2659 | struct log *msg = log_from_idx(idx); |
| 2660 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 2661 | l -= msg_print_text(msg, prev, true, NULL, 0); |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2662 | idx = log_next(idx); |
| 2663 | seq++; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 2664 | prev = msg->flags; |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2665 | } |
| 2666 | |
| 2667 | /* last message in next interation */ |
| 2668 | next_seq = seq; |
| 2669 | next_idx = idx; |
| 2670 | |
| 2671 | l = 0; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 2672 | prev = 0; |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2673 | while (seq < dumper->next_seq) { |
| 2674 | struct log *msg = log_from_idx(idx); |
| 2675 | |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 2676 | l += msg_print_text(msg, prev, syslog, buf + l, size - l); |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2677 | idx = log_next(idx); |
| 2678 | seq++; |
Kay Sievers | 5becfb1 | 2012-07-09 12:15:42 -0700 | [diff] [blame] | 2679 | prev = msg->flags; |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2680 | } |
| 2681 | |
| 2682 | dumper->next_seq = next_seq; |
| 2683 | dumper->next_idx = next_idx; |
| 2684 | ret = true; |
| 2685 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| 2686 | out: |
| 2687 | if (len) |
| 2688 | *len = l; |
| 2689 | return ret; |
| 2690 | } |
| 2691 | EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); |
| 2692 | |
| 2693 | /** |
Anton Vorontsov | 533827c | 2012-07-20 17:28:07 -0700 | [diff] [blame] | 2694 | * kmsg_dump_rewind_nolock - reset the interator (unlocked version) |
| 2695 | * @dumper: registered kmsg dumper |
| 2696 | * |
| 2697 | * Reset the dumper's iterator so that kmsg_dump_get_line() and |
| 2698 | * kmsg_dump_get_buffer() can be called again and used multiple |
| 2699 | * times within the same dumper.dump() callback. |
| 2700 | * |
| 2701 | * The function is similar to kmsg_dump_rewind(), but grabs no locks. |
| 2702 | */ |
| 2703 | void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) |
| 2704 | { |
| 2705 | dumper->cur_seq = clear_seq; |
| 2706 | dumper->cur_idx = clear_idx; |
| 2707 | dumper->next_seq = log_next_seq; |
| 2708 | dumper->next_idx = log_next_idx; |
| 2709 | } |
| 2710 | |
| 2711 | /** |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2712 | * kmsg_dump_rewind - reset the interator |
| 2713 | * @dumper: registered kmsg dumper |
| 2714 | * |
| 2715 | * Reset the dumper's iterator so that kmsg_dump_get_line() and |
| 2716 | * kmsg_dump_get_buffer() can be called again and used multiple |
| 2717 | * times within the same dumper.dump() callback. |
| 2718 | */ |
| 2719 | void kmsg_dump_rewind(struct kmsg_dumper *dumper) |
| 2720 | { |
| 2721 | unsigned long flags; |
| 2722 | |
| 2723 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
Anton Vorontsov | 533827c | 2012-07-20 17:28:07 -0700 | [diff] [blame] | 2724 | kmsg_dump_rewind_nolock(dumper); |
Kay Sievers | e2ae715 | 2012-06-15 14:07:51 +0200 | [diff] [blame] | 2725 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
| 2726 | } |
| 2727 | EXPORT_SYMBOL_GPL(kmsg_dump_rewind); |
Joe Perches | 7ef3d2f | 2008-02-08 04:21:25 -0800 | [diff] [blame] | 2728 | #endif |