Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | kmod, the new module loader (replaces kerneld) |
| 3 | Kirk Petersen |
| 4 | |
| 5 | Reorganized not to be a daemon by Adam Richter, with guidance |
| 6 | from Greg Zornetzer. |
| 7 | |
| 8 | Modified to avoid chroot and file sharing problems. |
| 9 | Mikael Pettersson |
| 10 | |
| 11 | Limit the concurrent number of kmod modprobes to catch loops from |
| 12 | "modprobe needs a service that is in a module". |
| 13 | Keith Owens <kaos@ocs.com.au> December 1999 |
| 14 | |
| 15 | Unblock all signals when we exec a usermode process. |
| 16 | Shuu Yamaguchi <shuu@wondernetworkresources.com> December 2000 |
| 17 | |
| 18 | call_usermodehelper wait flag, and remove exec_usermodehelper. |
| 19 | Rusty Russell <rusty@rustcorp.com.au> Jan 2003 |
| 20 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | #include <linux/module.h> |
| 22 | #include <linux/sched.h> |
| 23 | #include <linux/syscalls.h> |
| 24 | #include <linux/unistd.h> |
| 25 | #include <linux/kmod.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | #include <linux/slab.h> |
Kirill Korotaev | 6b3286e | 2006-12-08 02:37:56 -0800 | [diff] [blame] | 27 | #include <linux/mnt_namespace.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | #include <linux/completion.h> |
| 29 | #include <linux/file.h> |
Al Viro | 9f3acc3 | 2008-04-24 07:44:08 -0400 | [diff] [blame] | 30 | #include <linux/fdtable.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | #include <linux/workqueue.h> |
| 32 | #include <linux/security.h> |
| 33 | #include <linux/mount.h> |
| 34 | #include <linux/kernel.h> |
| 35 | #include <linux/init.h> |
Andi Kleen | d025c9d | 2006-09-30 23:29:28 -0700 | [diff] [blame] | 36 | #include <linux/resource.h> |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 37 | #include <linux/notifier.h> |
| 38 | #include <linux/suspend.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | #include <asm/uaccess.h> |
| 40 | |
| 41 | extern int max_threads; |
| 42 | |
| 43 | static struct workqueue_struct *khelper_wq; |
| 44 | |
Johannes Berg | a1ef5ad | 2008-07-08 19:00:17 +0200 | [diff] [blame] | 45 | #ifdef CONFIG_MODULES |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | |
| 47 | /* |
| 48 | modprobe_path is set via /proc/sys. |
| 49 | */ |
| 50 | char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe"; |
| 51 | |
| 52 | /** |
| 53 | * request_module - try to load a kernel module |
| 54 | * @fmt: printf style format string for the name of the module |
| 55 | * @varargs: arguements as specified in the format string |
| 56 | * |
| 57 | * Load a module using the user mode module loader. The function returns |
| 58 | * zero on success or a negative errno code on failure. Note that a |
| 59 | * successful module load does not mean the module did not then unload |
| 60 | * and exit on an error of its own. Callers must check that the service |
| 61 | * they requested is now available not blindly invoke it. |
| 62 | * |
| 63 | * If module auto-loading support is disabled then this function |
| 64 | * becomes a no-operation. |
| 65 | */ |
| 66 | int request_module(const char *fmt, ...) |
| 67 | { |
| 68 | va_list args; |
| 69 | char module_name[MODULE_NAME_LEN]; |
| 70 | unsigned int max_modprobes; |
| 71 | int ret; |
| 72 | char *argv[] = { modprobe_path, "-q", "--", module_name, NULL }; |
| 73 | static char *envp[] = { "HOME=/", |
| 74 | "TERM=linux", |
| 75 | "PATH=/sbin:/usr/sbin:/bin:/usr/bin", |
| 76 | NULL }; |
| 77 | static atomic_t kmod_concurrent = ATOMIC_INIT(0); |
| 78 | #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ |
| 79 | static int kmod_loop_msg; |
| 80 | |
| 81 | va_start(args, fmt); |
| 82 | ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); |
| 83 | va_end(args); |
| 84 | if (ret >= MODULE_NAME_LEN) |
| 85 | return -ENAMETOOLONG; |
| 86 | |
| 87 | /* If modprobe needs a service that is in a module, we get a recursive |
| 88 | * loop. Limit the number of running kmod threads to max_threads/2 or |
| 89 | * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method |
| 90 | * would be to run the parents of this process, counting how many times |
| 91 | * kmod was invoked. That would mean accessing the internals of the |
| 92 | * process tables to get the command line, proc_pid_cmdline is static |
| 93 | * and it is not worth changing the proc code just to handle this case. |
| 94 | * KAO. |
| 95 | * |
| 96 | * "trace the ppid" is simple, but will fail if someone's |
| 97 | * parent exits. I think this is as good as it gets. --RR |
| 98 | */ |
| 99 | max_modprobes = min(max_threads/2, MAX_KMOD_CONCURRENT); |
| 100 | atomic_inc(&kmod_concurrent); |
| 101 | if (atomic_read(&kmod_concurrent) > max_modprobes) { |
| 102 | /* We may be blaming an innocent here, but unlikely */ |
| 103 | if (kmod_loop_msg++ < 5) |
| 104 | printk(KERN_ERR |
| 105 | "request_module: runaway loop modprobe %s\n", |
| 106 | module_name); |
| 107 | atomic_dec(&kmod_concurrent); |
| 108 | return -ENOMEM; |
| 109 | } |
| 110 | |
| 111 | ret = call_usermodehelper(modprobe_path, argv, envp, 1); |
| 112 | atomic_dec(&kmod_concurrent); |
| 113 | return ret; |
| 114 | } |
| 115 | EXPORT_SYMBOL(request_module); |
Rusty Russell | 118a906 | 2008-10-17 02:38:36 -0500 | [diff] [blame] | 116 | #endif /* CONFIG_MODULES */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | |
| 118 | struct subprocess_info { |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 119 | struct work_struct work; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | struct completion *complete; |
| 121 | char *path; |
| 122 | char **argv; |
| 123 | char **envp; |
David Howells | 7888e7f | 2005-06-23 22:00:51 -0700 | [diff] [blame] | 124 | struct key *ring; |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 125 | enum umh_wait wait; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | int retval; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 127 | struct file *stdin; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 128 | void (*cleanup)(char **argv, char **envp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | }; |
| 130 | |
| 131 | /* |
| 132 | * This is the task which runs the usermode application |
| 133 | */ |
| 134 | static int ____call_usermodehelper(void *data) |
| 135 | { |
| 136 | struct subprocess_info *sub_info = data; |
David Howells | 20e1129 | 2005-10-30 15:02:44 -0800 | [diff] [blame] | 137 | struct key *new_session, *old_session; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | int retval; |
| 139 | |
David Howells | 7888e7f | 2005-06-23 22:00:51 -0700 | [diff] [blame] | 140 | /* Unblock all signals and set the session keyring. */ |
David Howells | 20e1129 | 2005-10-30 15:02:44 -0800 | [diff] [blame] | 141 | new_session = key_get(sub_info->ring); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 142 | spin_lock_irq(¤t->sighand->siglock); |
David Howells | 20e1129 | 2005-10-30 15:02:44 -0800 | [diff] [blame] | 143 | old_session = __install_session_keyring(current, new_session); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | flush_signal_handlers(current, 1); |
| 145 | sigemptyset(¤t->blocked); |
| 146 | recalc_sigpending(); |
| 147 | spin_unlock_irq(¤t->sighand->siglock); |
| 148 | |
David Howells | 7888e7f | 2005-06-23 22:00:51 -0700 | [diff] [blame] | 149 | key_put(old_session); |
| 150 | |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 151 | /* Install input pipe when needed */ |
| 152 | if (sub_info->stdin) { |
| 153 | struct files_struct *f = current->files; |
| 154 | struct fdtable *fdt; |
| 155 | /* no races because files should be private here */ |
| 156 | sys_close(0); |
| 157 | fd_install(0, sub_info->stdin); |
| 158 | spin_lock(&f->file_lock); |
| 159 | fdt = files_fdtable(f); |
| 160 | FD_SET(0, fdt->open_fds); |
| 161 | FD_CLR(0, fdt->close_on_exec); |
| 162 | spin_unlock(&f->file_lock); |
Andi Kleen | d025c9d | 2006-09-30 23:29:28 -0700 | [diff] [blame] | 163 | |
| 164 | /* and disallow core files too */ |
| 165 | current->signal->rlim[RLIMIT_CORE] = (struct rlimit){0, 0}; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 166 | } |
| 167 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 168 | /* We can run anywhere, unlike our parent keventd(). */ |
Mike Travis | f70316d | 2008-04-04 18:11:06 -0700 | [diff] [blame] | 169 | set_cpus_allowed_ptr(current, CPU_MASK_ALL_PTR); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | |
Jan Engelhardt | b73a7e7 | 2007-05-08 00:28:24 -0700 | [diff] [blame] | 171 | /* |
| 172 | * Our parent is keventd, which runs with elevated scheduling priority. |
| 173 | * Avoid propagating that into the userspace child. |
| 174 | */ |
| 175 | set_user_nice(current, 0); |
| 176 | |
Jan Blunck | db74ece | 2008-02-14 19:34:29 -0800 | [diff] [blame] | 177 | retval = kernel_execve(sub_info->path, sub_info->argv, sub_info->envp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | |
| 179 | /* Exec failed? */ |
| 180 | sub_info->retval = retval; |
| 181 | do_exit(0); |
| 182 | } |
| 183 | |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 184 | void call_usermodehelper_freeinfo(struct subprocess_info *info) |
| 185 | { |
| 186 | if (info->cleanup) |
| 187 | (*info->cleanup)(info->argv, info->envp); |
| 188 | kfree(info); |
| 189 | } |
| 190 | EXPORT_SYMBOL(call_usermodehelper_freeinfo); |
| 191 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | /* Keventd can't block, but this (a child) can. */ |
| 193 | static int wait_for_helper(void *data) |
| 194 | { |
| 195 | struct subprocess_info *sub_info = data; |
| 196 | pid_t pid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 197 | |
| 198 | /* Install a handler: if SIGCLD isn't handled sys_wait4 won't |
| 199 | * populate the status, but will return -ECHILD. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | allow_signal(SIGCHLD); |
| 201 | |
| 202 | pid = kernel_thread(____call_usermodehelper, sub_info, SIGCHLD); |
| 203 | if (pid < 0) { |
| 204 | sub_info->retval = pid; |
| 205 | } else { |
Björn Steinbrink | 111dbe0 | 2006-09-29 02:00:46 -0700 | [diff] [blame] | 206 | int ret; |
| 207 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | /* |
| 209 | * Normally it is bogus to call wait4() from in-kernel because |
| 210 | * wait4() wants to write the exit code to a userspace address. |
| 211 | * But wait_for_helper() always runs as keventd, and put_user() |
| 212 | * to a kernel address works OK for kernel threads, due to their |
| 213 | * having an mm_segment_t which spans the entire address space. |
| 214 | * |
| 215 | * Thus the __user pointer cast is valid here. |
| 216 | */ |
Björn Steinbrink | 111dbe0 | 2006-09-29 02:00:46 -0700 | [diff] [blame] | 217 | sys_wait4(pid, (int __user *)&ret, 0, NULL); |
| 218 | |
| 219 | /* |
| 220 | * If ret is 0, either ____call_usermodehelper failed and the |
| 221 | * real error code is already in sub_info->retval or |
| 222 | * sub_info->retval is 0 anyway, so don't mess with it then. |
| 223 | */ |
| 224 | if (ret) |
| 225 | sub_info->retval = ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 226 | } |
| 227 | |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 228 | if (sub_info->wait == UMH_NO_WAIT) |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 229 | call_usermodehelper_freeinfo(sub_info); |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 230 | else |
| 231 | complete(sub_info->complete); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | return 0; |
| 233 | } |
| 234 | |
| 235 | /* This is run by khelper thread */ |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 236 | static void __call_usermodehelper(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | { |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 238 | struct subprocess_info *sub_info = |
| 239 | container_of(work, struct subprocess_info, work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | pid_t pid; |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 241 | enum umh_wait wait = sub_info->wait; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | |
| 243 | /* CLONE_VFORK: wait until the usermode helper has execve'd |
| 244 | * successfully We need the data structures to stay around |
| 245 | * until that is done. */ |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 246 | if (wait == UMH_WAIT_PROC || wait == UMH_NO_WAIT) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 247 | pid = kernel_thread(wait_for_helper, sub_info, |
| 248 | CLONE_FS | CLONE_FILES | SIGCHLD); |
| 249 | else |
| 250 | pid = kernel_thread(____call_usermodehelper, sub_info, |
| 251 | CLONE_VFORK | SIGCHLD); |
| 252 | |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 253 | switch (wait) { |
| 254 | case UMH_NO_WAIT: |
| 255 | break; |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 256 | |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 257 | case UMH_WAIT_PROC: |
| 258 | if (pid > 0) |
| 259 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 260 | sub_info->retval = pid; |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 261 | /* FALLTHROUGH */ |
| 262 | |
| 263 | case UMH_WAIT_EXEC: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 264 | complete(sub_info->complete); |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 265 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 266 | } |
| 267 | |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 268 | #ifdef CONFIG_PM_SLEEP |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 269 | /* |
| 270 | * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY |
| 271 | * (used for preventing user land processes from being created after the user |
| 272 | * land has been frozen during a system-wide hibernation or suspend operation). |
| 273 | */ |
| 274 | static int usermodehelper_disabled; |
| 275 | |
| 276 | /* Number of helpers running */ |
| 277 | static atomic_t running_helpers = ATOMIC_INIT(0); |
| 278 | |
| 279 | /* |
| 280 | * Wait queue head used by usermodehelper_pm_callback() to wait for all running |
| 281 | * helpers to finish. |
| 282 | */ |
| 283 | static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq); |
| 284 | |
| 285 | /* |
| 286 | * Time to wait for running_helpers to become zero before the setting of |
| 287 | * usermodehelper_disabled in usermodehelper_pm_callback() fails |
| 288 | */ |
| 289 | #define RUNNING_HELPERS_TIMEOUT (5 * HZ) |
| 290 | |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 291 | /** |
| 292 | * usermodehelper_disable - prevent new helpers from being started |
| 293 | */ |
| 294 | int usermodehelper_disable(void) |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 295 | { |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 296 | long retval; |
| 297 | |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 298 | usermodehelper_disabled = 1; |
| 299 | smp_mb(); |
| 300 | /* |
| 301 | * From now on call_usermodehelper_exec() won't start any new |
| 302 | * helpers, so it is sufficient if running_helpers turns out to |
| 303 | * be zero at one point (it may be increased later, but that |
| 304 | * doesn't matter). |
| 305 | */ |
| 306 | retval = wait_event_timeout(running_helpers_waitq, |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 307 | atomic_read(&running_helpers) == 0, |
| 308 | RUNNING_HELPERS_TIMEOUT); |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 309 | if (retval) |
| 310 | return 0; |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 311 | |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 312 | usermodehelper_disabled = 0; |
| 313 | return -EAGAIN; |
| 314 | } |
| 315 | |
| 316 | /** |
| 317 | * usermodehelper_enable - allow new helpers to be started again |
| 318 | */ |
| 319 | void usermodehelper_enable(void) |
| 320 | { |
| 321 | usermodehelper_disabled = 0; |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 322 | } |
| 323 | |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 324 | static void helper_lock(void) |
| 325 | { |
| 326 | atomic_inc(&running_helpers); |
| 327 | smp_mb__after_atomic_inc(); |
| 328 | } |
| 329 | |
| 330 | static void helper_unlock(void) |
| 331 | { |
| 332 | if (atomic_dec_and_test(&running_helpers)) |
| 333 | wake_up(&running_helpers_waitq); |
| 334 | } |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 335 | #else /* CONFIG_PM_SLEEP */ |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 336 | #define usermodehelper_disabled 0 |
| 337 | |
| 338 | static inline void helper_lock(void) {} |
| 339 | static inline void helper_unlock(void) {} |
Rafael J. Wysocki | 1bfcf13 | 2008-10-15 22:01:21 -0700 | [diff] [blame] | 340 | #endif /* CONFIG_PM_SLEEP */ |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 341 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 342 | /** |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 343 | * call_usermodehelper_setup - prepare to call a usermode helper |
Randy Dunlap | 61df47c | 2007-07-26 10:40:56 -0700 | [diff] [blame] | 344 | * @path: path to usermode executable |
| 345 | * @argv: arg vector for process |
| 346 | * @envp: environment for process |
KOSAKI Motohiro | ac331d1 | 2008-07-25 01:45:38 -0700 | [diff] [blame] | 347 | * @gfp_mask: gfp mask for memory allocation |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | * |
Randy Dunlap | 61df47c | 2007-07-26 10:40:56 -0700 | [diff] [blame] | 349 | * Returns either %NULL on allocation failure, or a subprocess_info |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 350 | * structure. This should be passed to call_usermodehelper_exec to |
| 351 | * exec the process and free the structure. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 352 | */ |
KOSAKI Motohiro | ac331d1 | 2008-07-25 01:45:38 -0700 | [diff] [blame] | 353 | struct subprocess_info *call_usermodehelper_setup(char *path, char **argv, |
| 354 | char **envp, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | { |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 356 | struct subprocess_info *sub_info; |
KOSAKI Motohiro | ac331d1 | 2008-07-25 01:45:38 -0700 | [diff] [blame] | 357 | sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask); |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 358 | if (!sub_info) |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 359 | goto out; |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 360 | |
| 361 | INIT_WORK(&sub_info->work, __call_usermodehelper); |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 362 | sub_info->path = path; |
| 363 | sub_info->argv = argv; |
| 364 | sub_info->envp = envp; |
Andi Kleen | a98f0dd | 2007-02-13 13:26:23 +0100 | [diff] [blame] | 365 | |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 366 | out: |
| 367 | return sub_info; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 368 | } |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 369 | EXPORT_SYMBOL(call_usermodehelper_setup); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 370 | |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 371 | /** |
| 372 | * call_usermodehelper_setkeys - set the session keys for usermode helper |
| 373 | * @info: a subprocess_info returned by call_usermodehelper_setup |
| 374 | * @session_keyring: the session keyring for the process |
| 375 | */ |
| 376 | void call_usermodehelper_setkeys(struct subprocess_info *info, |
| 377 | struct key *session_keyring) |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 378 | { |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 379 | info->ring = session_keyring; |
| 380 | } |
| 381 | EXPORT_SYMBOL(call_usermodehelper_setkeys); |
| 382 | |
| 383 | /** |
| 384 | * call_usermodehelper_setcleanup - set a cleanup function |
| 385 | * @info: a subprocess_info returned by call_usermodehelper_setup |
| 386 | * @cleanup: a cleanup function |
| 387 | * |
| 388 | * The cleanup function is just befor ethe subprocess_info is about to |
| 389 | * be freed. This can be used for freeing the argv and envp. The |
| 390 | * Function must be runnable in either a process context or the |
| 391 | * context in which call_usermodehelper_exec is called. |
| 392 | */ |
| 393 | void call_usermodehelper_setcleanup(struct subprocess_info *info, |
| 394 | void (*cleanup)(char **argv, char **envp)) |
| 395 | { |
| 396 | info->cleanup = cleanup; |
| 397 | } |
| 398 | EXPORT_SYMBOL(call_usermodehelper_setcleanup); |
| 399 | |
| 400 | /** |
| 401 | * call_usermodehelper_stdinpipe - set up a pipe to be used for stdin |
| 402 | * @sub_info: a subprocess_info returned by call_usermodehelper_setup |
| 403 | * @filp: set to the write-end of a pipe |
| 404 | * |
| 405 | * This constructs a pipe, and sets the read end to be the stdin of the |
| 406 | * subprocess, and returns the write-end in *@filp. |
| 407 | */ |
| 408 | int call_usermodehelper_stdinpipe(struct subprocess_info *sub_info, |
| 409 | struct file **filp) |
| 410 | { |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 411 | struct file *f; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 412 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 413 | f = create_write_pipe(0); |
Akinobu Mita | 3cce485 | 2006-11-28 12:29:43 -0800 | [diff] [blame] | 414 | if (IS_ERR(f)) |
| 415 | return PTR_ERR(f); |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 416 | *filp = f; |
| 417 | |
Ulrich Drepper | be61a86 | 2008-07-23 21:29:40 -0700 | [diff] [blame] | 418 | f = create_read_pipe(f, 0); |
Akinobu Mita | 3cce485 | 2006-11-28 12:29:43 -0800 | [diff] [blame] | 419 | if (IS_ERR(f)) { |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 420 | free_write_pipe(*filp); |
Akinobu Mita | 3cce485 | 2006-11-28 12:29:43 -0800 | [diff] [blame] | 421 | return PTR_ERR(f); |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 422 | } |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 423 | sub_info->stdin = f; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 424 | |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 425 | return 0; |
| 426 | } |
| 427 | EXPORT_SYMBOL(call_usermodehelper_stdinpipe); |
| 428 | |
| 429 | /** |
| 430 | * call_usermodehelper_exec - start a usermode application |
| 431 | * @sub_info: information about the subprocessa |
| 432 | * @wait: wait for the application to finish and return status. |
| 433 | * when -1 don't wait at all, but you get no useful error back when |
| 434 | * the program couldn't be exec'ed. This makes it safe to call |
| 435 | * from interrupt context. |
| 436 | * |
| 437 | * Runs a user-space application. The application is started |
| 438 | * asynchronously if wait is not set, and runs as a child of keventd. |
| 439 | * (ie. it runs with full root capabilities). |
| 440 | */ |
| 441 | int call_usermodehelper_exec(struct subprocess_info *sub_info, |
Jeremy Fitzhardinge | 86313c4 | 2007-07-17 18:37:03 -0700 | [diff] [blame] | 442 | enum umh_wait wait) |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 443 | { |
| 444 | DECLARE_COMPLETION_ONSTACK(done); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 445 | int retval = 0; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 446 | |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 447 | helper_lock(); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 448 | if (sub_info->path[0] == '\0') |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 449 | goto out; |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 450 | |
Rafael J. Wysocki | 8cdd493 | 2007-07-19 01:47:36 -0700 | [diff] [blame] | 451 | if (!khelper_wq || usermodehelper_disabled) { |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 452 | retval = -EBUSY; |
| 453 | goto out; |
| 454 | } |
| 455 | |
| 456 | sub_info->complete = &done; |
| 457 | sub_info->wait = wait; |
| 458 | |
| 459 | queue_work(khelper_wq, &sub_info->work); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 460 | if (wait == UMH_NO_WAIT) /* task has freed sub_info */ |
| 461 | goto unlock; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 462 | wait_for_completion(&done); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 463 | retval = sub_info->retval; |
| 464 | |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 465 | out: |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 466 | call_usermodehelper_freeinfo(sub_info); |
Nigel Cunningham | 7846803 | 2008-01-17 15:21:21 -0800 | [diff] [blame] | 467 | unlock: |
Rafael J. Wysocki | ccd4b65 | 2007-07-19 01:47:37 -0700 | [diff] [blame] | 468 | helper_unlock(); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 469 | return retval; |
| 470 | } |
| 471 | EXPORT_SYMBOL(call_usermodehelper_exec); |
| 472 | |
| 473 | /** |
| 474 | * call_usermodehelper_pipe - call a usermode helper process with a pipe stdin |
| 475 | * @path: path to usermode executable |
| 476 | * @argv: arg vector for process |
| 477 | * @envp: environment for process |
| 478 | * @filp: set to the write-end of a pipe |
| 479 | * |
| 480 | * This is a simple wrapper which executes a usermode-helper function |
| 481 | * with a pipe as stdin. It is implemented entirely in terms of |
| 482 | * lower-level call_usermodehelper_* functions. |
| 483 | */ |
| 484 | int call_usermodehelper_pipe(char *path, char **argv, char **envp, |
| 485 | struct file **filp) |
| 486 | { |
| 487 | struct subprocess_info *sub_info; |
| 488 | int ret; |
| 489 | |
KOSAKI Motohiro | ac331d1 | 2008-07-25 01:45:38 -0700 | [diff] [blame] | 490 | sub_info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 491 | if (sub_info == NULL) |
| 492 | return -ENOMEM; |
| 493 | |
| 494 | ret = call_usermodehelper_stdinpipe(sub_info, filp); |
| 495 | if (ret < 0) |
| 496 | goto out; |
| 497 | |
Michael Ellerman | 3210f0e | 2007-09-11 15:23:51 -0700 | [diff] [blame] | 498 | return call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC); |
Jeremy Fitzhardinge | 0ab4dc9 | 2007-07-17 18:37:02 -0700 | [diff] [blame] | 499 | |
| 500 | out: |
| 501 | call_usermodehelper_freeinfo(sub_info); |
| 502 | return ret; |
Andi Kleen | e239ca5 | 2006-09-30 23:29:27 -0700 | [diff] [blame] | 503 | } |
| 504 | EXPORT_SYMBOL(call_usermodehelper_pipe); |
| 505 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | void __init usermodehelper_init(void) |
| 507 | { |
| 508 | khelper_wq = create_singlethread_workqueue("khelper"); |
| 509 | BUG_ON(!khelper_wq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 510 | } |