Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/ipc/msg.c |
| 3 | * Copyright (C) 1992 Krishna Balasubramanian |
| 4 | * |
| 5 | * Removed all the remaining kerneld mess |
| 6 | * Catch the -EFAULT stuff properly |
| 7 | * Use GFP_KERNEL for messages as in 1.2 |
| 8 | * Fixed up the unchecked user space derefs |
| 9 | * Copyright (C) 1998 Alan Cox & Andi Kleen |
| 10 | * |
| 11 | * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com> |
| 12 | * |
| 13 | * mostly rewritten, threaded and wake-one semantics added |
| 14 | * MSGMAX limit removed, sysctl's added |
Christian Kujau | 624dffc | 2006-01-15 02:43:54 +0100 | [diff] [blame] | 15 | * (c) 1999 Manfred Spraul <manfred@colorfullife.com> |
Steve Grubb | 073115d | 2006-04-02 17:07:33 -0400 | [diff] [blame^] | 16 | * |
| 17 | * support for audit of ipc object properties and permission changes |
| 18 | * Dustin Kirkland <dustin.kirkland@us.ibm.com> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | */ |
| 20 | |
Randy.Dunlap | c59ede7 | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 21 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | #include <linux/config.h> |
| 23 | #include <linux/slab.h> |
| 24 | #include <linux/msg.h> |
| 25 | #include <linux/spinlock.h> |
| 26 | #include <linux/init.h> |
| 27 | #include <linux/proc_fs.h> |
| 28 | #include <linux/list.h> |
| 29 | #include <linux/security.h> |
| 30 | #include <linux/sched.h> |
| 31 | #include <linux/syscalls.h> |
| 32 | #include <linux/audit.h> |
Mike Waychison | 19b4946 | 2005-09-06 15:17:10 -0700 | [diff] [blame] | 33 | #include <linux/seq_file.h> |
Ingo Molnar | 5f921ae | 2006-03-26 01:37:17 -0800 | [diff] [blame] | 34 | #include <linux/mutex.h> |
| 35 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | #include <asm/current.h> |
| 37 | #include <asm/uaccess.h> |
| 38 | #include "util.h" |
| 39 | |
| 40 | /* sysctl: */ |
| 41 | int msg_ctlmax = MSGMAX; |
| 42 | int msg_ctlmnb = MSGMNB; |
| 43 | int msg_ctlmni = MSGMNI; |
| 44 | |
| 45 | /* one msg_receiver structure for each sleeping receiver */ |
| 46 | struct msg_receiver { |
| 47 | struct list_head r_list; |
| 48 | struct task_struct* r_tsk; |
| 49 | |
| 50 | int r_mode; |
| 51 | long r_msgtype; |
| 52 | long r_maxsize; |
| 53 | |
| 54 | struct msg_msg* volatile r_msg; |
| 55 | }; |
| 56 | |
| 57 | /* one msg_sender for each sleeping sender */ |
| 58 | struct msg_sender { |
| 59 | struct list_head list; |
| 60 | struct task_struct* tsk; |
| 61 | }; |
| 62 | |
| 63 | #define SEARCH_ANY 1 |
| 64 | #define SEARCH_EQUAL 2 |
| 65 | #define SEARCH_NOTEQUAL 3 |
| 66 | #define SEARCH_LESSEQUAL 4 |
| 67 | |
| 68 | static atomic_t msg_bytes = ATOMIC_INIT(0); |
| 69 | static atomic_t msg_hdrs = ATOMIC_INIT(0); |
| 70 | |
| 71 | static struct ipc_ids msg_ids; |
| 72 | |
| 73 | #define msg_lock(id) ((struct msg_queue*)ipc_lock(&msg_ids,id)) |
| 74 | #define msg_unlock(msq) ipc_unlock(&(msq)->q_perm) |
| 75 | #define msg_rmid(id) ((struct msg_queue*)ipc_rmid(&msg_ids,id)) |
| 76 | #define msg_checkid(msq, msgid) \ |
| 77 | ipc_checkid(&msg_ids,&msq->q_perm,msgid) |
| 78 | #define msg_buildid(id, seq) \ |
| 79 | ipc_buildid(&msg_ids, id, seq) |
| 80 | |
| 81 | static void freeque (struct msg_queue *msq, int id); |
| 82 | static int newque (key_t key, int msgflg); |
| 83 | #ifdef CONFIG_PROC_FS |
Mike Waychison | 19b4946 | 2005-09-06 15:17:10 -0700 | [diff] [blame] | 84 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | #endif |
| 86 | |
| 87 | void __init msg_init (void) |
| 88 | { |
| 89 | ipc_init_ids(&msg_ids,msg_ctlmni); |
Mike Waychison | 19b4946 | 2005-09-06 15:17:10 -0700 | [diff] [blame] | 90 | ipc_init_proc_interface("sysvipc/msg", |
| 91 | " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", |
| 92 | &msg_ids, |
| 93 | sysvipc_msg_proc_show); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | } |
| 95 | |
| 96 | static int newque (key_t key, int msgflg) |
| 97 | { |
| 98 | int id; |
| 99 | int retval; |
| 100 | struct msg_queue *msq; |
| 101 | |
| 102 | msq = ipc_rcu_alloc(sizeof(*msq)); |
| 103 | if (!msq) |
| 104 | return -ENOMEM; |
| 105 | |
| 106 | msq->q_perm.mode = (msgflg & S_IRWXUGO); |
| 107 | msq->q_perm.key = key; |
| 108 | |
| 109 | msq->q_perm.security = NULL; |
| 110 | retval = security_msg_queue_alloc(msq); |
| 111 | if (retval) { |
| 112 | ipc_rcu_putref(msq); |
| 113 | return retval; |
| 114 | } |
| 115 | |
| 116 | id = ipc_addid(&msg_ids, &msq->q_perm, msg_ctlmni); |
| 117 | if(id == -1) { |
| 118 | security_msg_queue_free(msq); |
| 119 | ipc_rcu_putref(msq); |
| 120 | return -ENOSPC; |
| 121 | } |
| 122 | |
Mike Waychison | 19b4946 | 2005-09-06 15:17:10 -0700 | [diff] [blame] | 123 | msq->q_id = msg_buildid(id,msq->q_perm.seq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | msq->q_stime = msq->q_rtime = 0; |
| 125 | msq->q_ctime = get_seconds(); |
| 126 | msq->q_cbytes = msq->q_qnum = 0; |
| 127 | msq->q_qbytes = msg_ctlmnb; |
| 128 | msq->q_lspid = msq->q_lrpid = 0; |
| 129 | INIT_LIST_HEAD(&msq->q_messages); |
| 130 | INIT_LIST_HEAD(&msq->q_receivers); |
| 131 | INIT_LIST_HEAD(&msq->q_senders); |
| 132 | msg_unlock(msq); |
| 133 | |
Mike Waychison | 19b4946 | 2005-09-06 15:17:10 -0700 | [diff] [blame] | 134 | return msq->q_id; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | } |
| 136 | |
| 137 | static inline void ss_add(struct msg_queue* msq, struct msg_sender* mss) |
| 138 | { |
| 139 | mss->tsk=current; |
| 140 | current->state=TASK_INTERRUPTIBLE; |
| 141 | list_add_tail(&mss->list,&msq->q_senders); |
| 142 | } |
| 143 | |
| 144 | static inline void ss_del(struct msg_sender* mss) |
| 145 | { |
| 146 | if(mss->list.next != NULL) |
| 147 | list_del(&mss->list); |
| 148 | } |
| 149 | |
| 150 | static void ss_wakeup(struct list_head* h, int kill) |
| 151 | { |
| 152 | struct list_head *tmp; |
| 153 | |
| 154 | tmp = h->next; |
| 155 | while (tmp != h) { |
| 156 | struct msg_sender* mss; |
| 157 | |
| 158 | mss = list_entry(tmp,struct msg_sender,list); |
| 159 | tmp = tmp->next; |
| 160 | if(kill) |
| 161 | mss->list.next=NULL; |
| 162 | wake_up_process(mss->tsk); |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | static void expunge_all(struct msg_queue* msq, int res) |
| 167 | { |
| 168 | struct list_head *tmp; |
| 169 | |
| 170 | tmp = msq->q_receivers.next; |
| 171 | while (tmp != &msq->q_receivers) { |
| 172 | struct msg_receiver* msr; |
| 173 | |
| 174 | msr = list_entry(tmp,struct msg_receiver,r_list); |
| 175 | tmp = tmp->next; |
| 176 | msr->r_msg = NULL; |
| 177 | wake_up_process(msr->r_tsk); |
| 178 | smp_mb(); |
| 179 | msr->r_msg = ERR_PTR(res); |
| 180 | } |
| 181 | } |
| 182 | /* |
| 183 | * freeque() wakes up waiters on the sender and receiver waiting queue, |
| 184 | * removes the message queue from message queue ID |
| 185 | * array, and cleans up all the messages associated with this queue. |
| 186 | * |
Ingo Molnar | 5f921ae | 2006-03-26 01:37:17 -0800 | [diff] [blame] | 187 | * msg_ids.mutex and the spinlock for this message queue is hold |
| 188 | * before freeque() is called. msg_ids.mutex remains locked on exit. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | */ |
| 190 | static void freeque (struct msg_queue *msq, int id) |
| 191 | { |
| 192 | struct list_head *tmp; |
| 193 | |
| 194 | expunge_all(msq,-EIDRM); |
| 195 | ss_wakeup(&msq->q_senders,1); |
| 196 | msq = msg_rmid(id); |
| 197 | msg_unlock(msq); |
| 198 | |
| 199 | tmp = msq->q_messages.next; |
| 200 | while(tmp != &msq->q_messages) { |
| 201 | struct msg_msg* msg = list_entry(tmp,struct msg_msg,m_list); |
| 202 | tmp = tmp->next; |
| 203 | atomic_dec(&msg_hdrs); |
| 204 | free_msg(msg); |
| 205 | } |
| 206 | atomic_sub(msq->q_cbytes, &msg_bytes); |
| 207 | security_msg_queue_free(msq); |
| 208 | ipc_rcu_putref(msq); |
| 209 | } |
| 210 | |
| 211 | asmlinkage long sys_msgget (key_t key, int msgflg) |
| 212 | { |
| 213 | int id, ret = -EPERM; |
| 214 | struct msg_queue *msq; |
| 215 | |
Ingo Molnar | 5f921ae | 2006-03-26 01:37:17 -0800 | [diff] [blame] | 216 | mutex_lock(&msg_ids.mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | if (key == IPC_PRIVATE) |
| 218 | ret = newque(key, msgflg); |
| 219 | else if ((id = ipc_findkey(&msg_ids, key)) == -1) { /* key not used */ |
| 220 | if (!(msgflg & IPC_CREAT)) |
| 221 | ret = -ENOENT; |
| 222 | else |
| 223 | ret = newque(key, msgflg); |
| 224 | } else if (msgflg & IPC_CREAT && msgflg & IPC_EXCL) { |
| 225 | ret = -EEXIST; |
| 226 | } else { |
| 227 | msq = msg_lock(id); |
Eric Sesterhenn | 8cd5283 | 2006-03-24 18:44:22 +0100 | [diff] [blame] | 228 | BUG_ON(msq==NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 229 | if (ipcperms(&msq->q_perm, msgflg)) |
| 230 | ret = -EACCES; |
| 231 | else { |
| 232 | int qid = msg_buildid(id, msq->q_perm.seq); |
| 233 | ret = security_msg_queue_associate(msq, msgflg); |
| 234 | if (!ret) |
| 235 | ret = qid; |
| 236 | } |
| 237 | msg_unlock(msq); |
| 238 | } |
Ingo Molnar | 5f921ae | 2006-03-26 01:37:17 -0800 | [diff] [blame] | 239 | mutex_unlock(&msg_ids.mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | return ret; |
| 241 | } |
| 242 | |
| 243 | static inline unsigned long copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version) |
| 244 | { |
| 245 | switch(version) { |
| 246 | case IPC_64: |
| 247 | return copy_to_user (buf, in, sizeof(*in)); |
| 248 | case IPC_OLD: |
| 249 | { |
| 250 | struct msqid_ds out; |
| 251 | |
| 252 | memset(&out,0,sizeof(out)); |
| 253 | |
| 254 | ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm); |
| 255 | |
| 256 | out.msg_stime = in->msg_stime; |
| 257 | out.msg_rtime = in->msg_rtime; |
| 258 | out.msg_ctime = in->msg_ctime; |
| 259 | |
| 260 | if(in->msg_cbytes > USHRT_MAX) |
| 261 | out.msg_cbytes = USHRT_MAX; |
| 262 | else |
| 263 | out.msg_cbytes = in->msg_cbytes; |
| 264 | out.msg_lcbytes = in->msg_cbytes; |
| 265 | |
| 266 | if(in->msg_qnum > USHRT_MAX) |
| 267 | out.msg_qnum = USHRT_MAX; |
| 268 | else |
| 269 | out.msg_qnum = in->msg_qnum; |
| 270 | |
| 271 | if(in->msg_qbytes > USHRT_MAX) |
| 272 | out.msg_qbytes = USHRT_MAX; |
| 273 | else |
| 274 | out.msg_qbytes = in->msg_qbytes; |
| 275 | out.msg_lqbytes = in->msg_qbytes; |
| 276 | |
| 277 | out.msg_lspid = in->msg_lspid; |
| 278 | out.msg_lrpid = in->msg_lrpid; |
| 279 | |
| 280 | return copy_to_user (buf, &out, sizeof(out)); |
| 281 | } |
| 282 | default: |
| 283 | return -EINVAL; |
| 284 | } |
| 285 | } |
| 286 | |
| 287 | struct msq_setbuf { |
| 288 | unsigned long qbytes; |
| 289 | uid_t uid; |
| 290 | gid_t gid; |
| 291 | mode_t mode; |
| 292 | }; |
| 293 | |
| 294 | static inline unsigned long copy_msqid_from_user(struct msq_setbuf *out, void __user *buf, int version) |
| 295 | { |
| 296 | switch(version) { |
| 297 | case IPC_64: |
| 298 | { |
| 299 | struct msqid64_ds tbuf; |
| 300 | |
| 301 | if (copy_from_user (&tbuf, buf, sizeof (tbuf))) |
| 302 | return -EFAULT; |
| 303 | |
| 304 | out->qbytes = tbuf.msg_qbytes; |
| 305 | out->uid = tbuf.msg_perm.uid; |
| 306 | out->gid = tbuf.msg_perm.gid; |
| 307 | out->mode = tbuf.msg_perm.mode; |
| 308 | |
| 309 | return 0; |
| 310 | } |
| 311 | case IPC_OLD: |
| 312 | { |
| 313 | struct msqid_ds tbuf_old; |
| 314 | |
| 315 | if (copy_from_user (&tbuf_old, buf, sizeof (tbuf_old))) |
| 316 | return -EFAULT; |
| 317 | |
| 318 | out->uid = tbuf_old.msg_perm.uid; |
| 319 | out->gid = tbuf_old.msg_perm.gid; |
| 320 | out->mode = tbuf_old.msg_perm.mode; |
| 321 | |
| 322 | if(tbuf_old.msg_qbytes == 0) |
| 323 | out->qbytes = tbuf_old.msg_lqbytes; |
| 324 | else |
| 325 | out->qbytes = tbuf_old.msg_qbytes; |
| 326 | |
| 327 | return 0; |
| 328 | } |
| 329 | default: |
| 330 | return -EINVAL; |
| 331 | } |
| 332 | } |
| 333 | |
| 334 | asmlinkage long sys_msgctl (int msqid, int cmd, struct msqid_ds __user *buf) |
| 335 | { |
| 336 | int err, version; |
| 337 | struct msg_queue *msq; |
| 338 | struct msq_setbuf setbuf; |
| 339 | struct kern_ipc_perm *ipcp; |
| 340 | |
| 341 | if (msqid < 0 || cmd < 0) |
| 342 | return -EINVAL; |
| 343 | |
| 344 | version = ipc_parse_version(&cmd); |
| 345 | |
| 346 | switch (cmd) { |
| 347 | case IPC_INFO: |
| 348 | case MSG_INFO: |
| 349 | { |
| 350 | struct msginfo msginfo; |
| 351 | int max_id; |
| 352 | if (!buf) |
| 353 | return -EFAULT; |
| 354 | /* We must not return kernel stack data. |
| 355 | * due to padding, it's not enough |
| 356 | * to set all member fields. |
| 357 | */ |
| 358 | |
| 359 | err = security_msg_queue_msgctl(NULL, cmd); |
| 360 | if (err) |
| 361 | return err; |
| 362 | |
| 363 | memset(&msginfo,0,sizeof(msginfo)); |
| 364 | msginfo.msgmni = msg_ctlmni; |
| 365 | msginfo.msgmax = msg_ctlmax; |
| 366 | msginfo.msgmnb = msg_ctlmnb; |
| 367 | msginfo.msgssz = MSGSSZ; |
| 368 | msginfo.msgseg = MSGSEG; |
Ingo Molnar | 5f921ae | 2006-03-26 01:37:17 -0800 | [diff] [blame] | 369 | mutex_lock(&msg_ids.mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 370 | if (cmd == MSG_INFO) { |
| 371 | msginfo.msgpool = msg_ids.in_use; |
| 372 | msginfo.msgmap = atomic_read(&msg_hdrs); |
| 373 | msginfo.msgtql = atomic_read(&msg_bytes); |
| 374 | } else { |
| 375 | msginfo.msgmap = MSGMAP; |
| 376 | msginfo.msgpool = MSGPOOL; |
| 377 | msginfo.msgtql = MSGTQL; |
| 378 | } |
| 379 | max_id = msg_ids.max_id; |
Ingo Molnar | 5f921ae | 2006-03-26 01:37:17 -0800 | [diff] [blame] | 380 | mutex_unlock(&msg_ids.mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 381 | if (copy_to_user (buf, &msginfo, sizeof(struct msginfo))) |
| 382 | return -EFAULT; |
| 383 | return (max_id < 0) ? 0: max_id; |
| 384 | } |
| 385 | case MSG_STAT: |
| 386 | case IPC_STAT: |
| 387 | { |
| 388 | struct msqid64_ds tbuf; |
| 389 | int success_return; |
| 390 | if (!buf) |
| 391 | return -EFAULT; |
| 392 | if(cmd == MSG_STAT && msqid >= msg_ids.entries->size) |
| 393 | return -EINVAL; |
| 394 | |
| 395 | memset(&tbuf,0,sizeof(tbuf)); |
| 396 | |
| 397 | msq = msg_lock(msqid); |
| 398 | if (msq == NULL) |
| 399 | return -EINVAL; |
| 400 | |
| 401 | if(cmd == MSG_STAT) { |
| 402 | success_return = msg_buildid(msqid, msq->q_perm.seq); |
| 403 | } else { |
| 404 | err = -EIDRM; |
| 405 | if (msg_checkid(msq,msqid)) |
| 406 | goto out_unlock; |
| 407 | success_return = 0; |
| 408 | } |
| 409 | err = -EACCES; |
| 410 | if (ipcperms (&msq->q_perm, S_IRUGO)) |
| 411 | goto out_unlock; |
| 412 | |
| 413 | err = security_msg_queue_msgctl(msq, cmd); |
| 414 | if (err) |
| 415 | goto out_unlock; |
| 416 | |
| 417 | kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm); |
| 418 | tbuf.msg_stime = msq->q_stime; |
| 419 | tbuf.msg_rtime = msq->q_rtime; |
| 420 | tbuf.msg_ctime = msq->q_ctime; |
| 421 | tbuf.msg_cbytes = msq->q_cbytes; |
| 422 | tbuf.msg_qnum = msq->q_qnum; |
| 423 | tbuf.msg_qbytes = msq->q_qbytes; |
| 424 | tbuf.msg_lspid = msq->q_lspid; |
| 425 | tbuf.msg_lrpid = msq->q_lrpid; |
| 426 | msg_unlock(msq); |
| 427 | if (copy_msqid_to_user(buf, &tbuf, version)) |
| 428 | return -EFAULT; |
| 429 | return success_return; |
| 430 | } |
| 431 | case IPC_SET: |
| 432 | if (!buf) |
| 433 | return -EFAULT; |
| 434 | if (copy_msqid_from_user (&setbuf, buf, version)) |
| 435 | return -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 436 | break; |
| 437 | case IPC_RMID: |
| 438 | break; |
| 439 | default: |
| 440 | return -EINVAL; |
| 441 | } |
| 442 | |
Ingo Molnar | 5f921ae | 2006-03-26 01:37:17 -0800 | [diff] [blame] | 443 | mutex_lock(&msg_ids.mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 444 | msq = msg_lock(msqid); |
| 445 | err=-EINVAL; |
| 446 | if (msq == NULL) |
| 447 | goto out_up; |
| 448 | |
| 449 | err = -EIDRM; |
| 450 | if (msg_checkid(msq,msqid)) |
| 451 | goto out_unlock_up; |
| 452 | ipcp = &msq->q_perm; |
Steve Grubb | 073115d | 2006-04-02 17:07:33 -0400 | [diff] [blame^] | 453 | |
| 454 | err = audit_ipc_obj(ipcp); |
| 455 | if (err) |
| 456 | goto out_unlock_up; |
| 457 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 458 | err = -EPERM; |
| 459 | if (current->euid != ipcp->cuid && |
| 460 | current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN)) |
| 461 | /* We _could_ check for CAP_CHOWN above, but we don't */ |
| 462 | goto out_unlock_up; |
| 463 | |
| 464 | err = security_msg_queue_msgctl(msq, cmd); |
| 465 | if (err) |
| 466 | goto out_unlock_up; |
| 467 | |
| 468 | switch (cmd) { |
| 469 | case IPC_SET: |
| 470 | { |
Steve Grubb | 073115d | 2006-04-02 17:07:33 -0400 | [diff] [blame^] | 471 | err = audit_ipc_set_perm(setbuf.qbytes, setbuf.uid, setbuf.gid, setbuf.mode, ipcp); |
| 472 | if (err) |
Dustin Kirkland | 8c8570f | 2005-11-03 17:15:16 +0000 | [diff] [blame] | 473 | goto out_unlock_up; |
| 474 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | err = -EPERM; |
| 476 | if (setbuf.qbytes > msg_ctlmnb && !capable(CAP_SYS_RESOURCE)) |
| 477 | goto out_unlock_up; |
| 478 | |
| 479 | msq->q_qbytes = setbuf.qbytes; |
| 480 | |
| 481 | ipcp->uid = setbuf.uid; |
| 482 | ipcp->gid = setbuf.gid; |
| 483 | ipcp->mode = (ipcp->mode & ~S_IRWXUGO) | |
| 484 | (S_IRWXUGO & setbuf.mode); |
| 485 | msq->q_ctime = get_seconds(); |
| 486 | /* sleeping receivers might be excluded by |
| 487 | * stricter permissions. |
| 488 | */ |
| 489 | expunge_all(msq,-EAGAIN); |
| 490 | /* sleeping senders might be able to send |
| 491 | * due to a larger queue size. |
| 492 | */ |
| 493 | ss_wakeup(&msq->q_senders,0); |
| 494 | msg_unlock(msq); |
| 495 | break; |
| 496 | } |
| 497 | case IPC_RMID: |
| 498 | freeque (msq, msqid); |
| 499 | break; |
| 500 | } |
| 501 | err = 0; |
| 502 | out_up: |
Ingo Molnar | 5f921ae | 2006-03-26 01:37:17 -0800 | [diff] [blame] | 503 | mutex_unlock(&msg_ids.mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 504 | return err; |
| 505 | out_unlock_up: |
| 506 | msg_unlock(msq); |
| 507 | goto out_up; |
| 508 | out_unlock: |
| 509 | msg_unlock(msq); |
| 510 | return err; |
| 511 | } |
| 512 | |
| 513 | static int testmsg(struct msg_msg* msg,long type,int mode) |
| 514 | { |
| 515 | switch(mode) |
| 516 | { |
| 517 | case SEARCH_ANY: |
| 518 | return 1; |
| 519 | case SEARCH_LESSEQUAL: |
| 520 | if(msg->m_type <=type) |
| 521 | return 1; |
| 522 | break; |
| 523 | case SEARCH_EQUAL: |
| 524 | if(msg->m_type == type) |
| 525 | return 1; |
| 526 | break; |
| 527 | case SEARCH_NOTEQUAL: |
| 528 | if(msg->m_type != type) |
| 529 | return 1; |
| 530 | break; |
| 531 | } |
| 532 | return 0; |
| 533 | } |
| 534 | |
| 535 | static inline int pipelined_send(struct msg_queue* msq, struct msg_msg* msg) |
| 536 | { |
| 537 | struct list_head* tmp; |
| 538 | |
| 539 | tmp = msq->q_receivers.next; |
| 540 | while (tmp != &msq->q_receivers) { |
| 541 | struct msg_receiver* msr; |
| 542 | msr = list_entry(tmp,struct msg_receiver,r_list); |
| 543 | tmp = tmp->next; |
| 544 | if(testmsg(msg,msr->r_msgtype,msr->r_mode) && |
| 545 | !security_msg_queue_msgrcv(msq, msg, msr->r_tsk, msr->r_msgtype, msr->r_mode)) { |
| 546 | list_del(&msr->r_list); |
| 547 | if(msr->r_maxsize < msg->m_ts) { |
| 548 | msr->r_msg = NULL; |
| 549 | wake_up_process(msr->r_tsk); |
| 550 | smp_mb(); |
| 551 | msr->r_msg = ERR_PTR(-E2BIG); |
| 552 | } else { |
| 553 | msr->r_msg = NULL; |
| 554 | msq->q_lrpid = msr->r_tsk->pid; |
| 555 | msq->q_rtime = get_seconds(); |
| 556 | wake_up_process(msr->r_tsk); |
| 557 | smp_mb(); |
| 558 | msr->r_msg = msg; |
| 559 | return 1; |
| 560 | } |
| 561 | } |
| 562 | } |
| 563 | return 0; |
| 564 | } |
| 565 | |
| 566 | asmlinkage long sys_msgsnd (int msqid, struct msgbuf __user *msgp, size_t msgsz, int msgflg) |
| 567 | { |
| 568 | struct msg_queue *msq; |
| 569 | struct msg_msg *msg; |
| 570 | long mtype; |
| 571 | int err; |
| 572 | |
| 573 | if (msgsz > msg_ctlmax || (long) msgsz < 0 || msqid < 0) |
| 574 | return -EINVAL; |
| 575 | if (get_user(mtype, &msgp->mtype)) |
| 576 | return -EFAULT; |
| 577 | if (mtype < 1) |
| 578 | return -EINVAL; |
| 579 | |
| 580 | msg = load_msg(msgp->mtext, msgsz); |
| 581 | if(IS_ERR(msg)) |
| 582 | return PTR_ERR(msg); |
| 583 | |
| 584 | msg->m_type = mtype; |
| 585 | msg->m_ts = msgsz; |
| 586 | |
| 587 | msq = msg_lock(msqid); |
| 588 | err=-EINVAL; |
| 589 | if(msq==NULL) |
| 590 | goto out_free; |
| 591 | |
| 592 | err= -EIDRM; |
| 593 | if (msg_checkid(msq,msqid)) |
| 594 | goto out_unlock_free; |
| 595 | |
| 596 | for (;;) { |
| 597 | struct msg_sender s; |
| 598 | |
| 599 | err=-EACCES; |
| 600 | if (ipcperms(&msq->q_perm, S_IWUGO)) |
| 601 | goto out_unlock_free; |
| 602 | |
| 603 | err = security_msg_queue_msgsnd(msq, msg, msgflg); |
| 604 | if (err) |
| 605 | goto out_unlock_free; |
| 606 | |
| 607 | if(msgsz + msq->q_cbytes <= msq->q_qbytes && |
| 608 | 1 + msq->q_qnum <= msq->q_qbytes) { |
| 609 | break; |
| 610 | } |
| 611 | |
| 612 | /* queue full, wait: */ |
| 613 | if(msgflg&IPC_NOWAIT) { |
| 614 | err=-EAGAIN; |
| 615 | goto out_unlock_free; |
| 616 | } |
| 617 | ss_add(msq, &s); |
| 618 | ipc_rcu_getref(msq); |
| 619 | msg_unlock(msq); |
| 620 | schedule(); |
| 621 | |
| 622 | ipc_lock_by_ptr(&msq->q_perm); |
| 623 | ipc_rcu_putref(msq); |
| 624 | if (msq->q_perm.deleted) { |
| 625 | err = -EIDRM; |
| 626 | goto out_unlock_free; |
| 627 | } |
| 628 | ss_del(&s); |
| 629 | |
| 630 | if (signal_pending(current)) { |
| 631 | err=-ERESTARTNOHAND; |
| 632 | goto out_unlock_free; |
| 633 | } |
| 634 | } |
| 635 | |
| 636 | msq->q_lspid = current->tgid; |
| 637 | msq->q_stime = get_seconds(); |
| 638 | |
| 639 | if(!pipelined_send(msq,msg)) { |
| 640 | /* noone is waiting for this message, enqueue it */ |
| 641 | list_add_tail(&msg->m_list,&msq->q_messages); |
| 642 | msq->q_cbytes += msgsz; |
| 643 | msq->q_qnum++; |
| 644 | atomic_add(msgsz,&msg_bytes); |
| 645 | atomic_inc(&msg_hdrs); |
| 646 | } |
| 647 | |
| 648 | err = 0; |
| 649 | msg = NULL; |
| 650 | |
| 651 | out_unlock_free: |
| 652 | msg_unlock(msq); |
| 653 | out_free: |
| 654 | if(msg!=NULL) |
| 655 | free_msg(msg); |
| 656 | return err; |
| 657 | } |
| 658 | |
| 659 | static inline int convert_mode(long* msgtyp, int msgflg) |
| 660 | { |
| 661 | /* |
| 662 | * find message of correct type. |
| 663 | * msgtyp = 0 => get first. |
| 664 | * msgtyp > 0 => get first message of matching type. |
| 665 | * msgtyp < 0 => get message with least type must be < abs(msgtype). |
| 666 | */ |
| 667 | if(*msgtyp==0) |
| 668 | return SEARCH_ANY; |
| 669 | if(*msgtyp<0) { |
| 670 | *msgtyp=-(*msgtyp); |
| 671 | return SEARCH_LESSEQUAL; |
| 672 | } |
| 673 | if(msgflg & MSG_EXCEPT) |
| 674 | return SEARCH_NOTEQUAL; |
| 675 | return SEARCH_EQUAL; |
| 676 | } |
| 677 | |
| 678 | asmlinkage long sys_msgrcv (int msqid, struct msgbuf __user *msgp, size_t msgsz, |
| 679 | long msgtyp, int msgflg) |
| 680 | { |
| 681 | struct msg_queue *msq; |
| 682 | struct msg_msg *msg; |
| 683 | int mode; |
| 684 | |
| 685 | if (msqid < 0 || (long) msgsz < 0) |
| 686 | return -EINVAL; |
| 687 | mode = convert_mode(&msgtyp,msgflg); |
| 688 | |
| 689 | msq = msg_lock(msqid); |
| 690 | if(msq==NULL) |
| 691 | return -EINVAL; |
| 692 | |
| 693 | msg = ERR_PTR(-EIDRM); |
| 694 | if (msg_checkid(msq,msqid)) |
| 695 | goto out_unlock; |
| 696 | |
| 697 | for (;;) { |
| 698 | struct msg_receiver msr_d; |
| 699 | struct list_head* tmp; |
| 700 | |
| 701 | msg = ERR_PTR(-EACCES); |
| 702 | if (ipcperms (&msq->q_perm, S_IRUGO)) |
| 703 | goto out_unlock; |
| 704 | |
| 705 | msg = ERR_PTR(-EAGAIN); |
| 706 | tmp = msq->q_messages.next; |
| 707 | while (tmp != &msq->q_messages) { |
| 708 | struct msg_msg *walk_msg; |
| 709 | walk_msg = list_entry(tmp,struct msg_msg,m_list); |
| 710 | if(testmsg(walk_msg,msgtyp,mode) && |
| 711 | !security_msg_queue_msgrcv(msq, walk_msg, current, msgtyp, mode)) { |
| 712 | msg = walk_msg; |
| 713 | if(mode == SEARCH_LESSEQUAL && walk_msg->m_type != 1) { |
| 714 | msg=walk_msg; |
| 715 | msgtyp=walk_msg->m_type-1; |
| 716 | } else { |
| 717 | msg=walk_msg; |
| 718 | break; |
| 719 | } |
| 720 | } |
| 721 | tmp = tmp->next; |
| 722 | } |
| 723 | if(!IS_ERR(msg)) { |
| 724 | /* Found a suitable message. Unlink it from the queue. */ |
| 725 | if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { |
| 726 | msg = ERR_PTR(-E2BIG); |
| 727 | goto out_unlock; |
| 728 | } |
| 729 | list_del(&msg->m_list); |
| 730 | msq->q_qnum--; |
| 731 | msq->q_rtime = get_seconds(); |
| 732 | msq->q_lrpid = current->tgid; |
| 733 | msq->q_cbytes -= msg->m_ts; |
| 734 | atomic_sub(msg->m_ts,&msg_bytes); |
| 735 | atomic_dec(&msg_hdrs); |
| 736 | ss_wakeup(&msq->q_senders,0); |
| 737 | msg_unlock(msq); |
| 738 | break; |
| 739 | } |
| 740 | /* No message waiting. Wait for a message */ |
| 741 | if (msgflg & IPC_NOWAIT) { |
| 742 | msg = ERR_PTR(-ENOMSG); |
| 743 | goto out_unlock; |
| 744 | } |
| 745 | list_add_tail(&msr_d.r_list,&msq->q_receivers); |
| 746 | msr_d.r_tsk = current; |
| 747 | msr_d.r_msgtype = msgtyp; |
| 748 | msr_d.r_mode = mode; |
| 749 | if(msgflg & MSG_NOERROR) |
| 750 | msr_d.r_maxsize = INT_MAX; |
| 751 | else |
| 752 | msr_d.r_maxsize = msgsz; |
| 753 | msr_d.r_msg = ERR_PTR(-EAGAIN); |
| 754 | current->state = TASK_INTERRUPTIBLE; |
| 755 | msg_unlock(msq); |
| 756 | |
| 757 | schedule(); |
| 758 | |
| 759 | /* Lockless receive, part 1: |
| 760 | * Disable preemption. We don't hold a reference to the queue |
| 761 | * and getting a reference would defeat the idea of a lockless |
| 762 | * operation, thus the code relies on rcu to guarantee the |
| 763 | * existance of msq: |
| 764 | * Prior to destruction, expunge_all(-EIRDM) changes r_msg. |
| 765 | * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. |
| 766 | * rcu_read_lock() prevents preemption between reading r_msg |
| 767 | * and the spin_lock() inside ipc_lock_by_ptr(). |
| 768 | */ |
| 769 | rcu_read_lock(); |
| 770 | |
| 771 | /* Lockless receive, part 2: |
| 772 | * Wait until pipelined_send or expunge_all are outside of |
| 773 | * wake_up_process(). There is a race with exit(), see |
| 774 | * ipc/mqueue.c for the details. |
| 775 | */ |
| 776 | msg = (struct msg_msg*) msr_d.r_msg; |
| 777 | while (msg == NULL) { |
| 778 | cpu_relax(); |
| 779 | msg = (struct msg_msg*) msr_d.r_msg; |
| 780 | } |
| 781 | |
| 782 | /* Lockless receive, part 3: |
| 783 | * If there is a message or an error then accept it without |
| 784 | * locking. |
| 785 | */ |
| 786 | if(msg != ERR_PTR(-EAGAIN)) { |
| 787 | rcu_read_unlock(); |
| 788 | break; |
| 789 | } |
| 790 | |
| 791 | /* Lockless receive, part 3: |
| 792 | * Acquire the queue spinlock. |
| 793 | */ |
| 794 | ipc_lock_by_ptr(&msq->q_perm); |
| 795 | rcu_read_unlock(); |
| 796 | |
| 797 | /* Lockless receive, part 4: |
| 798 | * Repeat test after acquiring the spinlock. |
| 799 | */ |
| 800 | msg = (struct msg_msg*)msr_d.r_msg; |
| 801 | if(msg != ERR_PTR(-EAGAIN)) |
| 802 | goto out_unlock; |
| 803 | |
| 804 | list_del(&msr_d.r_list); |
| 805 | if (signal_pending(current)) { |
| 806 | msg = ERR_PTR(-ERESTARTNOHAND); |
| 807 | out_unlock: |
| 808 | msg_unlock(msq); |
| 809 | break; |
| 810 | } |
| 811 | } |
| 812 | if (IS_ERR(msg)) |
| 813 | return PTR_ERR(msg); |
| 814 | |
| 815 | msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz; |
| 816 | if (put_user (msg->m_type, &msgp->mtype) || |
| 817 | store_msg(msgp->mtext, msg, msgsz)) { |
| 818 | msgsz = -EFAULT; |
| 819 | } |
| 820 | free_msg(msg); |
| 821 | return msgsz; |
| 822 | } |
| 823 | |
| 824 | #ifdef CONFIG_PROC_FS |
Mike Waychison | 19b4946 | 2005-09-06 15:17:10 -0700 | [diff] [blame] | 825 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 826 | { |
Mike Waychison | 19b4946 | 2005-09-06 15:17:10 -0700 | [diff] [blame] | 827 | struct msg_queue *msq = it; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 828 | |
Mike Waychison | 19b4946 | 2005-09-06 15:17:10 -0700 | [diff] [blame] | 829 | return seq_printf(s, |
| 830 | "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n", |
| 831 | msq->q_perm.key, |
| 832 | msq->q_id, |
| 833 | msq->q_perm.mode, |
| 834 | msq->q_cbytes, |
| 835 | msq->q_qnum, |
| 836 | msq->q_lspid, |
| 837 | msq->q_lrpid, |
| 838 | msq->q_perm.uid, |
| 839 | msq->q_perm.gid, |
| 840 | msq->q_perm.cuid, |
| 841 | msq->q_perm.cgid, |
| 842 | msq->q_stime, |
| 843 | msq->q_rtime, |
| 844 | msq->q_ctime); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 845 | } |
| 846 | #endif |