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Commit | Line | Data |
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1da177e4 LT |
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 | |
624dffcb | 15 | * (c) 1999 Manfred Spraul <manfred@colorfullife.com> |
1da177e4 LT |
16 | */ |
17 | ||
c59ede7b | 18 | #include <linux/capability.h> |
1da177e4 LT |
19 | #include <linux/config.h> |
20 | #include <linux/slab.h> | |
21 | #include <linux/msg.h> | |
22 | #include <linux/spinlock.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/proc_fs.h> | |
25 | #include <linux/list.h> | |
26 | #include <linux/security.h> | |
27 | #include <linux/sched.h> | |
28 | #include <linux/syscalls.h> | |
29 | #include <linux/audit.h> | |
19b4946c | 30 | #include <linux/seq_file.h> |
5f921ae9 IM |
31 | #include <linux/mutex.h> |
32 | ||
1da177e4 LT |
33 | #include <asm/current.h> |
34 | #include <asm/uaccess.h> | |
35 | #include "util.h" | |
36 | ||
37 | /* sysctl: */ | |
38 | int msg_ctlmax = MSGMAX; | |
39 | int msg_ctlmnb = MSGMNB; | |
40 | int msg_ctlmni = MSGMNI; | |
41 | ||
42 | /* one msg_receiver structure for each sleeping receiver */ | |
43 | struct msg_receiver { | |
44 | struct list_head r_list; | |
45 | struct task_struct* r_tsk; | |
46 | ||
47 | int r_mode; | |
48 | long r_msgtype; | |
49 | long r_maxsize; | |
50 | ||
51 | struct msg_msg* volatile r_msg; | |
52 | }; | |
53 | ||
54 | /* one msg_sender for each sleeping sender */ | |
55 | struct msg_sender { | |
56 | struct list_head list; | |
57 | struct task_struct* tsk; | |
58 | }; | |
59 | ||
60 | #define SEARCH_ANY 1 | |
61 | #define SEARCH_EQUAL 2 | |
62 | #define SEARCH_NOTEQUAL 3 | |
63 | #define SEARCH_LESSEQUAL 4 | |
64 | ||
65 | static atomic_t msg_bytes = ATOMIC_INIT(0); | |
66 | static atomic_t msg_hdrs = ATOMIC_INIT(0); | |
67 | ||
68 | static struct ipc_ids msg_ids; | |
69 | ||
70 | #define msg_lock(id) ((struct msg_queue*)ipc_lock(&msg_ids,id)) | |
71 | #define msg_unlock(msq) ipc_unlock(&(msq)->q_perm) | |
72 | #define msg_rmid(id) ((struct msg_queue*)ipc_rmid(&msg_ids,id)) | |
73 | #define msg_checkid(msq, msgid) \ | |
74 | ipc_checkid(&msg_ids,&msq->q_perm,msgid) | |
75 | #define msg_buildid(id, seq) \ | |
76 | ipc_buildid(&msg_ids, id, seq) | |
77 | ||
78 | static void freeque (struct msg_queue *msq, int id); | |
79 | static int newque (key_t key, int msgflg); | |
80 | #ifdef CONFIG_PROC_FS | |
19b4946c | 81 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it); |
1da177e4 LT |
82 | #endif |
83 | ||
84 | void __init msg_init (void) | |
85 | { | |
86 | ipc_init_ids(&msg_ids,msg_ctlmni); | |
19b4946c MW |
87 | ipc_init_proc_interface("sysvipc/msg", |
88 | " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", | |
89 | &msg_ids, | |
90 | sysvipc_msg_proc_show); | |
1da177e4 LT |
91 | } |
92 | ||
93 | static int newque (key_t key, int msgflg) | |
94 | { | |
95 | int id; | |
96 | int retval; | |
97 | struct msg_queue *msq; | |
98 | ||
99 | msq = ipc_rcu_alloc(sizeof(*msq)); | |
100 | if (!msq) | |
101 | return -ENOMEM; | |
102 | ||
103 | msq->q_perm.mode = (msgflg & S_IRWXUGO); | |
104 | msq->q_perm.key = key; | |
105 | ||
106 | msq->q_perm.security = NULL; | |
107 | retval = security_msg_queue_alloc(msq); | |
108 | if (retval) { | |
109 | ipc_rcu_putref(msq); | |
110 | return retval; | |
111 | } | |
112 | ||
113 | id = ipc_addid(&msg_ids, &msq->q_perm, msg_ctlmni); | |
114 | if(id == -1) { | |
115 | security_msg_queue_free(msq); | |
116 | ipc_rcu_putref(msq); | |
117 | return -ENOSPC; | |
118 | } | |
119 | ||
19b4946c | 120 | msq->q_id = msg_buildid(id,msq->q_perm.seq); |
1da177e4 LT |
121 | msq->q_stime = msq->q_rtime = 0; |
122 | msq->q_ctime = get_seconds(); | |
123 | msq->q_cbytes = msq->q_qnum = 0; | |
124 | msq->q_qbytes = msg_ctlmnb; | |
125 | msq->q_lspid = msq->q_lrpid = 0; | |
126 | INIT_LIST_HEAD(&msq->q_messages); | |
127 | INIT_LIST_HEAD(&msq->q_receivers); | |
128 | INIT_LIST_HEAD(&msq->q_senders); | |
129 | msg_unlock(msq); | |
130 | ||
19b4946c | 131 | return msq->q_id; |
1da177e4 LT |
132 | } |
133 | ||
134 | static inline void ss_add(struct msg_queue* msq, struct msg_sender* mss) | |
135 | { | |
136 | mss->tsk=current; | |
137 | current->state=TASK_INTERRUPTIBLE; | |
138 | list_add_tail(&mss->list,&msq->q_senders); | |
139 | } | |
140 | ||
141 | static inline void ss_del(struct msg_sender* mss) | |
142 | { | |
143 | if(mss->list.next != NULL) | |
144 | list_del(&mss->list); | |
145 | } | |
146 | ||
147 | static void ss_wakeup(struct list_head* h, int kill) | |
148 | { | |
149 | struct list_head *tmp; | |
150 | ||
151 | tmp = h->next; | |
152 | while (tmp != h) { | |
153 | struct msg_sender* mss; | |
154 | ||
155 | mss = list_entry(tmp,struct msg_sender,list); | |
156 | tmp = tmp->next; | |
157 | if(kill) | |
158 | mss->list.next=NULL; | |
159 | wake_up_process(mss->tsk); | |
160 | } | |
161 | } | |
162 | ||
163 | static void expunge_all(struct msg_queue* msq, int res) | |
164 | { | |
165 | struct list_head *tmp; | |
166 | ||
167 | tmp = msq->q_receivers.next; | |
168 | while (tmp != &msq->q_receivers) { | |
169 | struct msg_receiver* msr; | |
170 | ||
171 | msr = list_entry(tmp,struct msg_receiver,r_list); | |
172 | tmp = tmp->next; | |
173 | msr->r_msg = NULL; | |
174 | wake_up_process(msr->r_tsk); | |
175 | smp_mb(); | |
176 | msr->r_msg = ERR_PTR(res); | |
177 | } | |
178 | } | |
179 | /* | |
180 | * freeque() wakes up waiters on the sender and receiver waiting queue, | |
181 | * removes the message queue from message queue ID | |
182 | * array, and cleans up all the messages associated with this queue. | |
183 | * | |
5f921ae9 IM |
184 | * msg_ids.mutex and the spinlock for this message queue is hold |
185 | * before freeque() is called. msg_ids.mutex remains locked on exit. | |
1da177e4 LT |
186 | */ |
187 | static void freeque (struct msg_queue *msq, int id) | |
188 | { | |
189 | struct list_head *tmp; | |
190 | ||
191 | expunge_all(msq,-EIDRM); | |
192 | ss_wakeup(&msq->q_senders,1); | |
193 | msq = msg_rmid(id); | |
194 | msg_unlock(msq); | |
195 | ||
196 | tmp = msq->q_messages.next; | |
197 | while(tmp != &msq->q_messages) { | |
198 | struct msg_msg* msg = list_entry(tmp,struct msg_msg,m_list); | |
199 | tmp = tmp->next; | |
200 | atomic_dec(&msg_hdrs); | |
201 | free_msg(msg); | |
202 | } | |
203 | atomic_sub(msq->q_cbytes, &msg_bytes); | |
204 | security_msg_queue_free(msq); | |
205 | ipc_rcu_putref(msq); | |
206 | } | |
207 | ||
208 | asmlinkage long sys_msgget (key_t key, int msgflg) | |
209 | { | |
210 | int id, ret = -EPERM; | |
211 | struct msg_queue *msq; | |
212 | ||
5f921ae9 | 213 | mutex_lock(&msg_ids.mutex); |
1da177e4 LT |
214 | if (key == IPC_PRIVATE) |
215 | ret = newque(key, msgflg); | |
216 | else if ((id = ipc_findkey(&msg_ids, key)) == -1) { /* key not used */ | |
217 | if (!(msgflg & IPC_CREAT)) | |
218 | ret = -ENOENT; | |
219 | else | |
220 | ret = newque(key, msgflg); | |
221 | } else if (msgflg & IPC_CREAT && msgflg & IPC_EXCL) { | |
222 | ret = -EEXIST; | |
223 | } else { | |
224 | msq = msg_lock(id); | |
8cd5283b | 225 | BUG_ON(msq==NULL); |
1da177e4 LT |
226 | if (ipcperms(&msq->q_perm, msgflg)) |
227 | ret = -EACCES; | |
228 | else { | |
229 | int qid = msg_buildid(id, msq->q_perm.seq); | |
230 | ret = security_msg_queue_associate(msq, msgflg); | |
231 | if (!ret) | |
232 | ret = qid; | |
233 | } | |
234 | msg_unlock(msq); | |
235 | } | |
5f921ae9 | 236 | mutex_unlock(&msg_ids.mutex); |
1da177e4 LT |
237 | return ret; |
238 | } | |
239 | ||
240 | static inline unsigned long copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version) | |
241 | { | |
242 | switch(version) { | |
243 | case IPC_64: | |
244 | return copy_to_user (buf, in, sizeof(*in)); | |
245 | case IPC_OLD: | |
246 | { | |
247 | struct msqid_ds out; | |
248 | ||
249 | memset(&out,0,sizeof(out)); | |
250 | ||
251 | ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm); | |
252 | ||
253 | out.msg_stime = in->msg_stime; | |
254 | out.msg_rtime = in->msg_rtime; | |
255 | out.msg_ctime = in->msg_ctime; | |
256 | ||
257 | if(in->msg_cbytes > USHRT_MAX) | |
258 | out.msg_cbytes = USHRT_MAX; | |
259 | else | |
260 | out.msg_cbytes = in->msg_cbytes; | |
261 | out.msg_lcbytes = in->msg_cbytes; | |
262 | ||
263 | if(in->msg_qnum > USHRT_MAX) | |
264 | out.msg_qnum = USHRT_MAX; | |
265 | else | |
266 | out.msg_qnum = in->msg_qnum; | |
267 | ||
268 | if(in->msg_qbytes > USHRT_MAX) | |
269 | out.msg_qbytes = USHRT_MAX; | |
270 | else | |
271 | out.msg_qbytes = in->msg_qbytes; | |
272 | out.msg_lqbytes = in->msg_qbytes; | |
273 | ||
274 | out.msg_lspid = in->msg_lspid; | |
275 | out.msg_lrpid = in->msg_lrpid; | |
276 | ||
277 | return copy_to_user (buf, &out, sizeof(out)); | |
278 | } | |
279 | default: | |
280 | return -EINVAL; | |
281 | } | |
282 | } | |
283 | ||
284 | struct msq_setbuf { | |
285 | unsigned long qbytes; | |
286 | uid_t uid; | |
287 | gid_t gid; | |
288 | mode_t mode; | |
289 | }; | |
290 | ||
291 | static inline unsigned long copy_msqid_from_user(struct msq_setbuf *out, void __user *buf, int version) | |
292 | { | |
293 | switch(version) { | |
294 | case IPC_64: | |
295 | { | |
296 | struct msqid64_ds tbuf; | |
297 | ||
298 | if (copy_from_user (&tbuf, buf, sizeof (tbuf))) | |
299 | return -EFAULT; | |
300 | ||
301 | out->qbytes = tbuf.msg_qbytes; | |
302 | out->uid = tbuf.msg_perm.uid; | |
303 | out->gid = tbuf.msg_perm.gid; | |
304 | out->mode = tbuf.msg_perm.mode; | |
305 | ||
306 | return 0; | |
307 | } | |
308 | case IPC_OLD: | |
309 | { | |
310 | struct msqid_ds tbuf_old; | |
311 | ||
312 | if (copy_from_user (&tbuf_old, buf, sizeof (tbuf_old))) | |
313 | return -EFAULT; | |
314 | ||
315 | out->uid = tbuf_old.msg_perm.uid; | |
316 | out->gid = tbuf_old.msg_perm.gid; | |
317 | out->mode = tbuf_old.msg_perm.mode; | |
318 | ||
319 | if(tbuf_old.msg_qbytes == 0) | |
320 | out->qbytes = tbuf_old.msg_lqbytes; | |
321 | else | |
322 | out->qbytes = tbuf_old.msg_qbytes; | |
323 | ||
324 | return 0; | |
325 | } | |
326 | default: | |
327 | return -EINVAL; | |
328 | } | |
329 | } | |
330 | ||
331 | asmlinkage long sys_msgctl (int msqid, int cmd, struct msqid_ds __user *buf) | |
332 | { | |
333 | int err, version; | |
334 | struct msg_queue *msq; | |
335 | struct msq_setbuf setbuf; | |
336 | struct kern_ipc_perm *ipcp; | |
337 | ||
338 | if (msqid < 0 || cmd < 0) | |
339 | return -EINVAL; | |
340 | ||
341 | version = ipc_parse_version(&cmd); | |
342 | ||
343 | switch (cmd) { | |
344 | case IPC_INFO: | |
345 | case MSG_INFO: | |
346 | { | |
347 | struct msginfo msginfo; | |
348 | int max_id; | |
349 | if (!buf) | |
350 | return -EFAULT; | |
351 | /* We must not return kernel stack data. | |
352 | * due to padding, it's not enough | |
353 | * to set all member fields. | |
354 | */ | |
355 | ||
356 | err = security_msg_queue_msgctl(NULL, cmd); | |
357 | if (err) | |
358 | return err; | |
359 | ||
360 | memset(&msginfo,0,sizeof(msginfo)); | |
361 | msginfo.msgmni = msg_ctlmni; | |
362 | msginfo.msgmax = msg_ctlmax; | |
363 | msginfo.msgmnb = msg_ctlmnb; | |
364 | msginfo.msgssz = MSGSSZ; | |
365 | msginfo.msgseg = MSGSEG; | |
5f921ae9 | 366 | mutex_lock(&msg_ids.mutex); |
1da177e4 LT |
367 | if (cmd == MSG_INFO) { |
368 | msginfo.msgpool = msg_ids.in_use; | |
369 | msginfo.msgmap = atomic_read(&msg_hdrs); | |
370 | msginfo.msgtql = atomic_read(&msg_bytes); | |
371 | } else { | |
372 | msginfo.msgmap = MSGMAP; | |
373 | msginfo.msgpool = MSGPOOL; | |
374 | msginfo.msgtql = MSGTQL; | |
375 | } | |
376 | max_id = msg_ids.max_id; | |
5f921ae9 | 377 | mutex_unlock(&msg_ids.mutex); |
1da177e4 LT |
378 | if (copy_to_user (buf, &msginfo, sizeof(struct msginfo))) |
379 | return -EFAULT; | |
380 | return (max_id < 0) ? 0: max_id; | |
381 | } | |
382 | case MSG_STAT: | |
383 | case IPC_STAT: | |
384 | { | |
385 | struct msqid64_ds tbuf; | |
386 | int success_return; | |
387 | if (!buf) | |
388 | return -EFAULT; | |
389 | if(cmd == MSG_STAT && msqid >= msg_ids.entries->size) | |
390 | return -EINVAL; | |
391 | ||
392 | memset(&tbuf,0,sizeof(tbuf)); | |
393 | ||
394 | msq = msg_lock(msqid); | |
395 | if (msq == NULL) | |
396 | return -EINVAL; | |
397 | ||
398 | if(cmd == MSG_STAT) { | |
399 | success_return = msg_buildid(msqid, msq->q_perm.seq); | |
400 | } else { | |
401 | err = -EIDRM; | |
402 | if (msg_checkid(msq,msqid)) | |
403 | goto out_unlock; | |
404 | success_return = 0; | |
405 | } | |
406 | err = -EACCES; | |
407 | if (ipcperms (&msq->q_perm, S_IRUGO)) | |
408 | goto out_unlock; | |
409 | ||
410 | err = security_msg_queue_msgctl(msq, cmd); | |
411 | if (err) | |
412 | goto out_unlock; | |
413 | ||
414 | kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm); | |
415 | tbuf.msg_stime = msq->q_stime; | |
416 | tbuf.msg_rtime = msq->q_rtime; | |
417 | tbuf.msg_ctime = msq->q_ctime; | |
418 | tbuf.msg_cbytes = msq->q_cbytes; | |
419 | tbuf.msg_qnum = msq->q_qnum; | |
420 | tbuf.msg_qbytes = msq->q_qbytes; | |
421 | tbuf.msg_lspid = msq->q_lspid; | |
422 | tbuf.msg_lrpid = msq->q_lrpid; | |
423 | msg_unlock(msq); | |
424 | if (copy_msqid_to_user(buf, &tbuf, version)) | |
425 | return -EFAULT; | |
426 | return success_return; | |
427 | } | |
428 | case IPC_SET: | |
429 | if (!buf) | |
430 | return -EFAULT; | |
431 | if (copy_msqid_from_user (&setbuf, buf, version)) | |
432 | return -EFAULT; | |
1da177e4 LT |
433 | break; |
434 | case IPC_RMID: | |
435 | break; | |
436 | default: | |
437 | return -EINVAL; | |
438 | } | |
439 | ||
5f921ae9 | 440 | mutex_lock(&msg_ids.mutex); |
1da177e4 LT |
441 | msq = msg_lock(msqid); |
442 | err=-EINVAL; | |
443 | if (msq == NULL) | |
444 | goto out_up; | |
445 | ||
446 | err = -EIDRM; | |
447 | if (msg_checkid(msq,msqid)) | |
448 | goto out_unlock_up; | |
449 | ipcp = &msq->q_perm; | |
450 | err = -EPERM; | |
451 | if (current->euid != ipcp->cuid && | |
452 | current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN)) | |
453 | /* We _could_ check for CAP_CHOWN above, but we don't */ | |
454 | goto out_unlock_up; | |
455 | ||
456 | err = security_msg_queue_msgctl(msq, cmd); | |
457 | if (err) | |
458 | goto out_unlock_up; | |
459 | ||
460 | switch (cmd) { | |
461 | case IPC_SET: | |
462 | { | |
8c8570fb DK |
463 | if ((err = audit_ipc_perms(setbuf.qbytes, setbuf.uid, setbuf.gid, setbuf.mode, ipcp))) |
464 | goto out_unlock_up; | |
465 | ||
1da177e4 LT |
466 | err = -EPERM; |
467 | if (setbuf.qbytes > msg_ctlmnb && !capable(CAP_SYS_RESOURCE)) | |
468 | goto out_unlock_up; | |
469 | ||
470 | msq->q_qbytes = setbuf.qbytes; | |
471 | ||
472 | ipcp->uid = setbuf.uid; | |
473 | ipcp->gid = setbuf.gid; | |
474 | ipcp->mode = (ipcp->mode & ~S_IRWXUGO) | | |
475 | (S_IRWXUGO & setbuf.mode); | |
476 | msq->q_ctime = get_seconds(); | |
477 | /* sleeping receivers might be excluded by | |
478 | * stricter permissions. | |
479 | */ | |
480 | expunge_all(msq,-EAGAIN); | |
481 | /* sleeping senders might be able to send | |
482 | * due to a larger queue size. | |
483 | */ | |
484 | ss_wakeup(&msq->q_senders,0); | |
485 | msg_unlock(msq); | |
486 | break; | |
487 | } | |
488 | case IPC_RMID: | |
489 | freeque (msq, msqid); | |
490 | break; | |
491 | } | |
492 | err = 0; | |
493 | out_up: | |
5f921ae9 | 494 | mutex_unlock(&msg_ids.mutex); |
1da177e4 LT |
495 | return err; |
496 | out_unlock_up: | |
497 | msg_unlock(msq); | |
498 | goto out_up; | |
499 | out_unlock: | |
500 | msg_unlock(msq); | |
501 | return err; | |
502 | } | |
503 | ||
504 | static int testmsg(struct msg_msg* msg,long type,int mode) | |
505 | { | |
506 | switch(mode) | |
507 | { | |
508 | case SEARCH_ANY: | |
509 | return 1; | |
510 | case SEARCH_LESSEQUAL: | |
511 | if(msg->m_type <=type) | |
512 | return 1; | |
513 | break; | |
514 | case SEARCH_EQUAL: | |
515 | if(msg->m_type == type) | |
516 | return 1; | |
517 | break; | |
518 | case SEARCH_NOTEQUAL: | |
519 | if(msg->m_type != type) | |
520 | return 1; | |
521 | break; | |
522 | } | |
523 | return 0; | |
524 | } | |
525 | ||
526 | static inline int pipelined_send(struct msg_queue* msq, struct msg_msg* msg) | |
527 | { | |
528 | struct list_head* tmp; | |
529 | ||
530 | tmp = msq->q_receivers.next; | |
531 | while (tmp != &msq->q_receivers) { | |
532 | struct msg_receiver* msr; | |
533 | msr = list_entry(tmp,struct msg_receiver,r_list); | |
534 | tmp = tmp->next; | |
535 | if(testmsg(msg,msr->r_msgtype,msr->r_mode) && | |
536 | !security_msg_queue_msgrcv(msq, msg, msr->r_tsk, msr->r_msgtype, msr->r_mode)) { | |
537 | list_del(&msr->r_list); | |
538 | if(msr->r_maxsize < msg->m_ts) { | |
539 | msr->r_msg = NULL; | |
540 | wake_up_process(msr->r_tsk); | |
541 | smp_mb(); | |
542 | msr->r_msg = ERR_PTR(-E2BIG); | |
543 | } else { | |
544 | msr->r_msg = NULL; | |
545 | msq->q_lrpid = msr->r_tsk->pid; | |
546 | msq->q_rtime = get_seconds(); | |
547 | wake_up_process(msr->r_tsk); | |
548 | smp_mb(); | |
549 | msr->r_msg = msg; | |
550 | return 1; | |
551 | } | |
552 | } | |
553 | } | |
554 | return 0; | |
555 | } | |
556 | ||
557 | asmlinkage long sys_msgsnd (int msqid, struct msgbuf __user *msgp, size_t msgsz, int msgflg) | |
558 | { | |
559 | struct msg_queue *msq; | |
560 | struct msg_msg *msg; | |
561 | long mtype; | |
562 | int err; | |
563 | ||
564 | if (msgsz > msg_ctlmax || (long) msgsz < 0 || msqid < 0) | |
565 | return -EINVAL; | |
566 | if (get_user(mtype, &msgp->mtype)) | |
567 | return -EFAULT; | |
568 | if (mtype < 1) | |
569 | return -EINVAL; | |
570 | ||
571 | msg = load_msg(msgp->mtext, msgsz); | |
572 | if(IS_ERR(msg)) | |
573 | return PTR_ERR(msg); | |
574 | ||
575 | msg->m_type = mtype; | |
576 | msg->m_ts = msgsz; | |
577 | ||
578 | msq = msg_lock(msqid); | |
579 | err=-EINVAL; | |
580 | if(msq==NULL) | |
581 | goto out_free; | |
582 | ||
583 | err= -EIDRM; | |
584 | if (msg_checkid(msq,msqid)) | |
585 | goto out_unlock_free; | |
586 | ||
587 | for (;;) { | |
588 | struct msg_sender s; | |
589 | ||
590 | err=-EACCES; | |
591 | if (ipcperms(&msq->q_perm, S_IWUGO)) | |
592 | goto out_unlock_free; | |
593 | ||
594 | err = security_msg_queue_msgsnd(msq, msg, msgflg); | |
595 | if (err) | |
596 | goto out_unlock_free; | |
597 | ||
598 | if(msgsz + msq->q_cbytes <= msq->q_qbytes && | |
599 | 1 + msq->q_qnum <= msq->q_qbytes) { | |
600 | break; | |
601 | } | |
602 | ||
603 | /* queue full, wait: */ | |
604 | if(msgflg&IPC_NOWAIT) { | |
605 | err=-EAGAIN; | |
606 | goto out_unlock_free; | |
607 | } | |
608 | ss_add(msq, &s); | |
609 | ipc_rcu_getref(msq); | |
610 | msg_unlock(msq); | |
611 | schedule(); | |
612 | ||
613 | ipc_lock_by_ptr(&msq->q_perm); | |
614 | ipc_rcu_putref(msq); | |
615 | if (msq->q_perm.deleted) { | |
616 | err = -EIDRM; | |
617 | goto out_unlock_free; | |
618 | } | |
619 | ss_del(&s); | |
620 | ||
621 | if (signal_pending(current)) { | |
622 | err=-ERESTARTNOHAND; | |
623 | goto out_unlock_free; | |
624 | } | |
625 | } | |
626 | ||
627 | msq->q_lspid = current->tgid; | |
628 | msq->q_stime = get_seconds(); | |
629 | ||
630 | if(!pipelined_send(msq,msg)) { | |
631 | /* noone is waiting for this message, enqueue it */ | |
632 | list_add_tail(&msg->m_list,&msq->q_messages); | |
633 | msq->q_cbytes += msgsz; | |
634 | msq->q_qnum++; | |
635 | atomic_add(msgsz,&msg_bytes); | |
636 | atomic_inc(&msg_hdrs); | |
637 | } | |
638 | ||
639 | err = 0; | |
640 | msg = NULL; | |
641 | ||
642 | out_unlock_free: | |
643 | msg_unlock(msq); | |
644 | out_free: | |
645 | if(msg!=NULL) | |
646 | free_msg(msg); | |
647 | return err; | |
648 | } | |
649 | ||
650 | static inline int convert_mode(long* msgtyp, int msgflg) | |
651 | { | |
652 | /* | |
653 | * find message of correct type. | |
654 | * msgtyp = 0 => get first. | |
655 | * msgtyp > 0 => get first message of matching type. | |
656 | * msgtyp < 0 => get message with least type must be < abs(msgtype). | |
657 | */ | |
658 | if(*msgtyp==0) | |
659 | return SEARCH_ANY; | |
660 | if(*msgtyp<0) { | |
661 | *msgtyp=-(*msgtyp); | |
662 | return SEARCH_LESSEQUAL; | |
663 | } | |
664 | if(msgflg & MSG_EXCEPT) | |
665 | return SEARCH_NOTEQUAL; | |
666 | return SEARCH_EQUAL; | |
667 | } | |
668 | ||
669 | asmlinkage long sys_msgrcv (int msqid, struct msgbuf __user *msgp, size_t msgsz, | |
670 | long msgtyp, int msgflg) | |
671 | { | |
672 | struct msg_queue *msq; | |
673 | struct msg_msg *msg; | |
674 | int mode; | |
675 | ||
676 | if (msqid < 0 || (long) msgsz < 0) | |
677 | return -EINVAL; | |
678 | mode = convert_mode(&msgtyp,msgflg); | |
679 | ||
680 | msq = msg_lock(msqid); | |
681 | if(msq==NULL) | |
682 | return -EINVAL; | |
683 | ||
684 | msg = ERR_PTR(-EIDRM); | |
685 | if (msg_checkid(msq,msqid)) | |
686 | goto out_unlock; | |
687 | ||
688 | for (;;) { | |
689 | struct msg_receiver msr_d; | |
690 | struct list_head* tmp; | |
691 | ||
692 | msg = ERR_PTR(-EACCES); | |
693 | if (ipcperms (&msq->q_perm, S_IRUGO)) | |
694 | goto out_unlock; | |
695 | ||
696 | msg = ERR_PTR(-EAGAIN); | |
697 | tmp = msq->q_messages.next; | |
698 | while (tmp != &msq->q_messages) { | |
699 | struct msg_msg *walk_msg; | |
700 | walk_msg = list_entry(tmp,struct msg_msg,m_list); | |
701 | if(testmsg(walk_msg,msgtyp,mode) && | |
702 | !security_msg_queue_msgrcv(msq, walk_msg, current, msgtyp, mode)) { | |
703 | msg = walk_msg; | |
704 | if(mode == SEARCH_LESSEQUAL && walk_msg->m_type != 1) { | |
705 | msg=walk_msg; | |
706 | msgtyp=walk_msg->m_type-1; | |
707 | } else { | |
708 | msg=walk_msg; | |
709 | break; | |
710 | } | |
711 | } | |
712 | tmp = tmp->next; | |
713 | } | |
714 | if(!IS_ERR(msg)) { | |
715 | /* Found a suitable message. Unlink it from the queue. */ | |
716 | if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { | |
717 | msg = ERR_PTR(-E2BIG); | |
718 | goto out_unlock; | |
719 | } | |
720 | list_del(&msg->m_list); | |
721 | msq->q_qnum--; | |
722 | msq->q_rtime = get_seconds(); | |
723 | msq->q_lrpid = current->tgid; | |
724 | msq->q_cbytes -= msg->m_ts; | |
725 | atomic_sub(msg->m_ts,&msg_bytes); | |
726 | atomic_dec(&msg_hdrs); | |
727 | ss_wakeup(&msq->q_senders,0); | |
728 | msg_unlock(msq); | |
729 | break; | |
730 | } | |
731 | /* No message waiting. Wait for a message */ | |
732 | if (msgflg & IPC_NOWAIT) { | |
733 | msg = ERR_PTR(-ENOMSG); | |
734 | goto out_unlock; | |
735 | } | |
736 | list_add_tail(&msr_d.r_list,&msq->q_receivers); | |
737 | msr_d.r_tsk = current; | |
738 | msr_d.r_msgtype = msgtyp; | |
739 | msr_d.r_mode = mode; | |
740 | if(msgflg & MSG_NOERROR) | |
741 | msr_d.r_maxsize = INT_MAX; | |
742 | else | |
743 | msr_d.r_maxsize = msgsz; | |
744 | msr_d.r_msg = ERR_PTR(-EAGAIN); | |
745 | current->state = TASK_INTERRUPTIBLE; | |
746 | msg_unlock(msq); | |
747 | ||
748 | schedule(); | |
749 | ||
750 | /* Lockless receive, part 1: | |
751 | * Disable preemption. We don't hold a reference to the queue | |
752 | * and getting a reference would defeat the idea of a lockless | |
753 | * operation, thus the code relies on rcu to guarantee the | |
754 | * existance of msq: | |
755 | * Prior to destruction, expunge_all(-EIRDM) changes r_msg. | |
756 | * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. | |
757 | * rcu_read_lock() prevents preemption between reading r_msg | |
758 | * and the spin_lock() inside ipc_lock_by_ptr(). | |
759 | */ | |
760 | rcu_read_lock(); | |
761 | ||
762 | /* Lockless receive, part 2: | |
763 | * Wait until pipelined_send or expunge_all are outside of | |
764 | * wake_up_process(). There is a race with exit(), see | |
765 | * ipc/mqueue.c for the details. | |
766 | */ | |
767 | msg = (struct msg_msg*) msr_d.r_msg; | |
768 | while (msg == NULL) { | |
769 | cpu_relax(); | |
770 | msg = (struct msg_msg*) msr_d.r_msg; | |
771 | } | |
772 | ||
773 | /* Lockless receive, part 3: | |
774 | * If there is a message or an error then accept it without | |
775 | * locking. | |
776 | */ | |
777 | if(msg != ERR_PTR(-EAGAIN)) { | |
778 | rcu_read_unlock(); | |
779 | break; | |
780 | } | |
781 | ||
782 | /* Lockless receive, part 3: | |
783 | * Acquire the queue spinlock. | |
784 | */ | |
785 | ipc_lock_by_ptr(&msq->q_perm); | |
786 | rcu_read_unlock(); | |
787 | ||
788 | /* Lockless receive, part 4: | |
789 | * Repeat test after acquiring the spinlock. | |
790 | */ | |
791 | msg = (struct msg_msg*)msr_d.r_msg; | |
792 | if(msg != ERR_PTR(-EAGAIN)) | |
793 | goto out_unlock; | |
794 | ||
795 | list_del(&msr_d.r_list); | |
796 | if (signal_pending(current)) { | |
797 | msg = ERR_PTR(-ERESTARTNOHAND); | |
798 | out_unlock: | |
799 | msg_unlock(msq); | |
800 | break; | |
801 | } | |
802 | } | |
803 | if (IS_ERR(msg)) | |
804 | return PTR_ERR(msg); | |
805 | ||
806 | msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz; | |
807 | if (put_user (msg->m_type, &msgp->mtype) || | |
808 | store_msg(msgp->mtext, msg, msgsz)) { | |
809 | msgsz = -EFAULT; | |
810 | } | |
811 | free_msg(msg); | |
812 | return msgsz; | |
813 | } | |
814 | ||
815 | #ifdef CONFIG_PROC_FS | |
19b4946c | 816 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it) |
1da177e4 | 817 | { |
19b4946c MW |
818 | struct msg_queue *msq = it; |
819 | ||
820 | return seq_printf(s, | |
821 | "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n", | |
822 | msq->q_perm.key, | |
823 | msq->q_id, | |
824 | msq->q_perm.mode, | |
825 | msq->q_cbytes, | |
826 | msq->q_qnum, | |
827 | msq->q_lspid, | |
828 | msq->q_lrpid, | |
829 | msq->q_perm.uid, | |
830 | msq->q_perm.gid, | |
831 | msq->q_perm.cuid, | |
832 | msq->q_perm.cgid, | |
833 | msq->q_stime, | |
834 | msq->q_rtime, | |
835 | msq->q_ctime); | |
1da177e4 LT |
836 | } |
837 | #endif |