Commit | Line | Data |
---|---|---|
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> |
073115d6 SG |
16 | * |
17 | * support for audit of ipc object properties and permission changes | |
18 | * Dustin Kirkland <dustin.kirkland@us.ibm.com> | |
1da177e4 LT |
19 | */ |
20 | ||
c59ede7b | 21 | #include <linux/capability.h> |
1da177e4 LT |
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> | |
19b4946c | 33 | #include <linux/seq_file.h> |
5f921ae9 IM |
34 | #include <linux/mutex.h> |
35 | ||
1da177e4 LT |
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 | |
19b4946c | 84 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it); |
1da177e4 LT |
85 | #endif |
86 | ||
87 | void __init msg_init (void) | |
88 | { | |
89 | ipc_init_ids(&msg_ids,msg_ctlmni); | |
19b4946c MW |
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); | |
1da177e4 LT |
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 | ||
19b4946c | 123 | msq->q_id = msg_buildid(id,msq->q_perm.seq); |
1da177e4 LT |
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 | ||
19b4946c | 134 | return msq->q_id; |
1da177e4 LT |
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 | * | |
5f921ae9 IM |
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. | |
1da177e4 LT |
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 | ||
5f921ae9 | 216 | mutex_lock(&msg_ids.mutex); |
1da177e4 LT |
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); | |
8cd5283b | 228 | BUG_ON(msq==NULL); |
1da177e4 LT |
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 | } | |
5f921ae9 | 239 | mutex_unlock(&msg_ids.mutex); |
1da177e4 LT |
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; | |
5f921ae9 | 369 | mutex_lock(&msg_ids.mutex); |
1da177e4 LT |
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; | |
5f921ae9 | 380 | mutex_unlock(&msg_ids.mutex); |
1da177e4 LT |
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; | |
1da177e4 LT |
436 | break; |
437 | case IPC_RMID: | |
438 | break; | |
439 | default: | |
440 | return -EINVAL; | |
441 | } | |
442 | ||
5f921ae9 | 443 | mutex_lock(&msg_ids.mutex); |
1da177e4 LT |
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; | |
073115d6 SG |
453 | |
454 | err = audit_ipc_obj(ipcp); | |
455 | if (err) | |
456 | goto out_unlock_up; | |
ac03221a LK |
457 | if (cmd==IPC_SET) { |
458 | err = audit_ipc_set_perm(setbuf.qbytes, setbuf.uid, setbuf.gid, setbuf.mode); | |
459 | if (err) | |
460 | goto out_unlock_up; | |
461 | } | |
073115d6 | 462 | |
1da177e4 LT |
463 | err = -EPERM; |
464 | if (current->euid != ipcp->cuid && | |
465 | current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN)) | |
466 | /* We _could_ check for CAP_CHOWN above, but we don't */ | |
467 | goto out_unlock_up; | |
468 | ||
469 | err = security_msg_queue_msgctl(msq, cmd); | |
470 | if (err) | |
471 | goto out_unlock_up; | |
472 | ||
473 | switch (cmd) { | |
474 | case IPC_SET: | |
475 | { | |
476 | err = -EPERM; | |
477 | if (setbuf.qbytes > msg_ctlmnb && !capable(CAP_SYS_RESOURCE)) | |
478 | goto out_unlock_up; | |
479 | ||
480 | msq->q_qbytes = setbuf.qbytes; | |
481 | ||
482 | ipcp->uid = setbuf.uid; | |
483 | ipcp->gid = setbuf.gid; | |
484 | ipcp->mode = (ipcp->mode & ~S_IRWXUGO) | | |
485 | (S_IRWXUGO & setbuf.mode); | |
486 | msq->q_ctime = get_seconds(); | |
487 | /* sleeping receivers might be excluded by | |
488 | * stricter permissions. | |
489 | */ | |
490 | expunge_all(msq,-EAGAIN); | |
491 | /* sleeping senders might be able to send | |
492 | * due to a larger queue size. | |
493 | */ | |
494 | ss_wakeup(&msq->q_senders,0); | |
495 | msg_unlock(msq); | |
496 | break; | |
497 | } | |
498 | case IPC_RMID: | |
499 | freeque (msq, msqid); | |
500 | break; | |
501 | } | |
502 | err = 0; | |
503 | out_up: | |
5f921ae9 | 504 | mutex_unlock(&msg_ids.mutex); |
1da177e4 LT |
505 | return err; |
506 | out_unlock_up: | |
507 | msg_unlock(msq); | |
508 | goto out_up; | |
509 | out_unlock: | |
510 | msg_unlock(msq); | |
511 | return err; | |
512 | } | |
513 | ||
514 | static int testmsg(struct msg_msg* msg,long type,int mode) | |
515 | { | |
516 | switch(mode) | |
517 | { | |
518 | case SEARCH_ANY: | |
519 | return 1; | |
520 | case SEARCH_LESSEQUAL: | |
521 | if(msg->m_type <=type) | |
522 | return 1; | |
523 | break; | |
524 | case SEARCH_EQUAL: | |
525 | if(msg->m_type == type) | |
526 | return 1; | |
527 | break; | |
528 | case SEARCH_NOTEQUAL: | |
529 | if(msg->m_type != type) | |
530 | return 1; | |
531 | break; | |
532 | } | |
533 | return 0; | |
534 | } | |
535 | ||
536 | static inline int pipelined_send(struct msg_queue* msq, struct msg_msg* msg) | |
537 | { | |
538 | struct list_head* tmp; | |
539 | ||
540 | tmp = msq->q_receivers.next; | |
541 | while (tmp != &msq->q_receivers) { | |
542 | struct msg_receiver* msr; | |
543 | msr = list_entry(tmp,struct msg_receiver,r_list); | |
544 | tmp = tmp->next; | |
545 | if(testmsg(msg,msr->r_msgtype,msr->r_mode) && | |
546 | !security_msg_queue_msgrcv(msq, msg, msr->r_tsk, msr->r_msgtype, msr->r_mode)) { | |
547 | list_del(&msr->r_list); | |
548 | if(msr->r_maxsize < msg->m_ts) { | |
549 | msr->r_msg = NULL; | |
550 | wake_up_process(msr->r_tsk); | |
551 | smp_mb(); | |
552 | msr->r_msg = ERR_PTR(-E2BIG); | |
553 | } else { | |
554 | msr->r_msg = NULL; | |
555 | msq->q_lrpid = msr->r_tsk->pid; | |
556 | msq->q_rtime = get_seconds(); | |
557 | wake_up_process(msr->r_tsk); | |
558 | smp_mb(); | |
559 | msr->r_msg = msg; | |
560 | return 1; | |
561 | } | |
562 | } | |
563 | } | |
564 | return 0; | |
565 | } | |
566 | ||
567 | asmlinkage long sys_msgsnd (int msqid, struct msgbuf __user *msgp, size_t msgsz, int msgflg) | |
568 | { | |
569 | struct msg_queue *msq; | |
570 | struct msg_msg *msg; | |
571 | long mtype; | |
572 | int err; | |
573 | ||
574 | if (msgsz > msg_ctlmax || (long) msgsz < 0 || msqid < 0) | |
575 | return -EINVAL; | |
576 | if (get_user(mtype, &msgp->mtype)) | |
577 | return -EFAULT; | |
578 | if (mtype < 1) | |
579 | return -EINVAL; | |
580 | ||
581 | msg = load_msg(msgp->mtext, msgsz); | |
582 | if(IS_ERR(msg)) | |
583 | return PTR_ERR(msg); | |
584 | ||
585 | msg->m_type = mtype; | |
586 | msg->m_ts = msgsz; | |
587 | ||
588 | msq = msg_lock(msqid); | |
589 | err=-EINVAL; | |
590 | if(msq==NULL) | |
591 | goto out_free; | |
592 | ||
593 | err= -EIDRM; | |
594 | if (msg_checkid(msq,msqid)) | |
595 | goto out_unlock_free; | |
596 | ||
597 | for (;;) { | |
598 | struct msg_sender s; | |
599 | ||
600 | err=-EACCES; | |
601 | if (ipcperms(&msq->q_perm, S_IWUGO)) | |
602 | goto out_unlock_free; | |
603 | ||
604 | err = security_msg_queue_msgsnd(msq, msg, msgflg); | |
605 | if (err) | |
606 | goto out_unlock_free; | |
607 | ||
608 | if(msgsz + msq->q_cbytes <= msq->q_qbytes && | |
609 | 1 + msq->q_qnum <= msq->q_qbytes) { | |
610 | break; | |
611 | } | |
612 | ||
613 | /* queue full, wait: */ | |
614 | if(msgflg&IPC_NOWAIT) { | |
615 | err=-EAGAIN; | |
616 | goto out_unlock_free; | |
617 | } | |
618 | ss_add(msq, &s); | |
619 | ipc_rcu_getref(msq); | |
620 | msg_unlock(msq); | |
621 | schedule(); | |
622 | ||
623 | ipc_lock_by_ptr(&msq->q_perm); | |
624 | ipc_rcu_putref(msq); | |
625 | if (msq->q_perm.deleted) { | |
626 | err = -EIDRM; | |
627 | goto out_unlock_free; | |
628 | } | |
629 | ss_del(&s); | |
630 | ||
631 | if (signal_pending(current)) { | |
632 | err=-ERESTARTNOHAND; | |
633 | goto out_unlock_free; | |
634 | } | |
635 | } | |
636 | ||
637 | msq->q_lspid = current->tgid; | |
638 | msq->q_stime = get_seconds(); | |
639 | ||
640 | if(!pipelined_send(msq,msg)) { | |
641 | /* noone is waiting for this message, enqueue it */ | |
642 | list_add_tail(&msg->m_list,&msq->q_messages); | |
643 | msq->q_cbytes += msgsz; | |
644 | msq->q_qnum++; | |
645 | atomic_add(msgsz,&msg_bytes); | |
646 | atomic_inc(&msg_hdrs); | |
647 | } | |
648 | ||
649 | err = 0; | |
650 | msg = NULL; | |
651 | ||
652 | out_unlock_free: | |
653 | msg_unlock(msq); | |
654 | out_free: | |
655 | if(msg!=NULL) | |
656 | free_msg(msg); | |
657 | return err; | |
658 | } | |
659 | ||
660 | static inline int convert_mode(long* msgtyp, int msgflg) | |
661 | { | |
662 | /* | |
663 | * find message of correct type. | |
664 | * msgtyp = 0 => get first. | |
665 | * msgtyp > 0 => get first message of matching type. | |
666 | * msgtyp < 0 => get message with least type must be < abs(msgtype). | |
667 | */ | |
668 | if(*msgtyp==0) | |
669 | return SEARCH_ANY; | |
670 | if(*msgtyp<0) { | |
671 | *msgtyp=-(*msgtyp); | |
672 | return SEARCH_LESSEQUAL; | |
673 | } | |
674 | if(msgflg & MSG_EXCEPT) | |
675 | return SEARCH_NOTEQUAL; | |
676 | return SEARCH_EQUAL; | |
677 | } | |
678 | ||
679 | asmlinkage long sys_msgrcv (int msqid, struct msgbuf __user *msgp, size_t msgsz, | |
680 | long msgtyp, int msgflg) | |
681 | { | |
682 | struct msg_queue *msq; | |
683 | struct msg_msg *msg; | |
684 | int mode; | |
685 | ||
686 | if (msqid < 0 || (long) msgsz < 0) | |
687 | return -EINVAL; | |
688 | mode = convert_mode(&msgtyp,msgflg); | |
689 | ||
690 | msq = msg_lock(msqid); | |
691 | if(msq==NULL) | |
692 | return -EINVAL; | |
693 | ||
694 | msg = ERR_PTR(-EIDRM); | |
695 | if (msg_checkid(msq,msqid)) | |
696 | goto out_unlock; | |
697 | ||
698 | for (;;) { | |
699 | struct msg_receiver msr_d; | |
700 | struct list_head* tmp; | |
701 | ||
702 | msg = ERR_PTR(-EACCES); | |
703 | if (ipcperms (&msq->q_perm, S_IRUGO)) | |
704 | goto out_unlock; | |
705 | ||
706 | msg = ERR_PTR(-EAGAIN); | |
707 | tmp = msq->q_messages.next; | |
708 | while (tmp != &msq->q_messages) { | |
709 | struct msg_msg *walk_msg; | |
710 | walk_msg = list_entry(tmp,struct msg_msg,m_list); | |
711 | if(testmsg(walk_msg,msgtyp,mode) && | |
712 | !security_msg_queue_msgrcv(msq, walk_msg, current, msgtyp, mode)) { | |
713 | msg = walk_msg; | |
714 | if(mode == SEARCH_LESSEQUAL && walk_msg->m_type != 1) { | |
715 | msg=walk_msg; | |
716 | msgtyp=walk_msg->m_type-1; | |
717 | } else { | |
718 | msg=walk_msg; | |
719 | break; | |
720 | } | |
721 | } | |
722 | tmp = tmp->next; | |
723 | } | |
724 | if(!IS_ERR(msg)) { | |
725 | /* Found a suitable message. Unlink it from the queue. */ | |
726 | if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { | |
727 | msg = ERR_PTR(-E2BIG); | |
728 | goto out_unlock; | |
729 | } | |
730 | list_del(&msg->m_list); | |
731 | msq->q_qnum--; | |
732 | msq->q_rtime = get_seconds(); | |
733 | msq->q_lrpid = current->tgid; | |
734 | msq->q_cbytes -= msg->m_ts; | |
735 | atomic_sub(msg->m_ts,&msg_bytes); | |
736 | atomic_dec(&msg_hdrs); | |
737 | ss_wakeup(&msq->q_senders,0); | |
738 | msg_unlock(msq); | |
739 | break; | |
740 | } | |
741 | /* No message waiting. Wait for a message */ | |
742 | if (msgflg & IPC_NOWAIT) { | |
743 | msg = ERR_PTR(-ENOMSG); | |
744 | goto out_unlock; | |
745 | } | |
746 | list_add_tail(&msr_d.r_list,&msq->q_receivers); | |
747 | msr_d.r_tsk = current; | |
748 | msr_d.r_msgtype = msgtyp; | |
749 | msr_d.r_mode = mode; | |
750 | if(msgflg & MSG_NOERROR) | |
751 | msr_d.r_maxsize = INT_MAX; | |
752 | else | |
753 | msr_d.r_maxsize = msgsz; | |
754 | msr_d.r_msg = ERR_PTR(-EAGAIN); | |
755 | current->state = TASK_INTERRUPTIBLE; | |
756 | msg_unlock(msq); | |
757 | ||
758 | schedule(); | |
759 | ||
760 | /* Lockless receive, part 1: | |
761 | * Disable preemption. We don't hold a reference to the queue | |
762 | * and getting a reference would defeat the idea of a lockless | |
763 | * operation, thus the code relies on rcu to guarantee the | |
764 | * existance of msq: | |
765 | * Prior to destruction, expunge_all(-EIRDM) changes r_msg. | |
766 | * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. | |
767 | * rcu_read_lock() prevents preemption between reading r_msg | |
768 | * and the spin_lock() inside ipc_lock_by_ptr(). | |
769 | */ | |
770 | rcu_read_lock(); | |
771 | ||
772 | /* Lockless receive, part 2: | |
773 | * Wait until pipelined_send or expunge_all are outside of | |
774 | * wake_up_process(). There is a race with exit(), see | |
775 | * ipc/mqueue.c for the details. | |
776 | */ | |
777 | msg = (struct msg_msg*) msr_d.r_msg; | |
778 | while (msg == NULL) { | |
779 | cpu_relax(); | |
780 | msg = (struct msg_msg*) msr_d.r_msg; | |
781 | } | |
782 | ||
783 | /* Lockless receive, part 3: | |
784 | * If there is a message or an error then accept it without | |
785 | * locking. | |
786 | */ | |
787 | if(msg != ERR_PTR(-EAGAIN)) { | |
788 | rcu_read_unlock(); | |
789 | break; | |
790 | } | |
791 | ||
792 | /* Lockless receive, part 3: | |
793 | * Acquire the queue spinlock. | |
794 | */ | |
795 | ipc_lock_by_ptr(&msq->q_perm); | |
796 | rcu_read_unlock(); | |
797 | ||
798 | /* Lockless receive, part 4: | |
799 | * Repeat test after acquiring the spinlock. | |
800 | */ | |
801 | msg = (struct msg_msg*)msr_d.r_msg; | |
802 | if(msg != ERR_PTR(-EAGAIN)) | |
803 | goto out_unlock; | |
804 | ||
805 | list_del(&msr_d.r_list); | |
806 | if (signal_pending(current)) { | |
807 | msg = ERR_PTR(-ERESTARTNOHAND); | |
808 | out_unlock: | |
809 | msg_unlock(msq); | |
810 | break; | |
811 | } | |
812 | } | |
813 | if (IS_ERR(msg)) | |
814 | return PTR_ERR(msg); | |
815 | ||
816 | msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz; | |
817 | if (put_user (msg->m_type, &msgp->mtype) || | |
818 | store_msg(msgp->mtext, msg, msgsz)) { | |
819 | msgsz = -EFAULT; | |
820 | } | |
821 | free_msg(msg); | |
822 | return msgsz; | |
823 | } | |
824 | ||
825 | #ifdef CONFIG_PROC_FS | |
19b4946c | 826 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it) |
1da177e4 | 827 | { |
19b4946c MW |
828 | struct msg_queue *msq = it; |
829 | ||
830 | return seq_printf(s, | |
831 | "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n", | |
832 | msq->q_perm.key, | |
833 | msq->q_id, | |
834 | msq->q_perm.mode, | |
835 | msq->q_cbytes, | |
836 | msq->q_qnum, | |
837 | msq->q_lspid, | |
838 | msq->q_lrpid, | |
839 | msq->q_perm.uid, | |
840 | msq->q_perm.gid, | |
841 | msq->q_perm.cuid, | |
842 | msq->q_perm.cgid, | |
843 | msq->q_stime, | |
844 | msq->q_rtime, | |
845 | msq->q_ctime); | |
1da177e4 LT |
846 | } |
847 | #endif |