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/slab.h> |
23 | #include <linux/msg.h> | |
24 | #include <linux/spinlock.h> | |
25 | #include <linux/init.h> | |
26 | #include <linux/proc_fs.h> | |
27 | #include <linux/list.h> | |
28 | #include <linux/security.h> | |
29 | #include <linux/sched.h> | |
30 | #include <linux/syscalls.h> | |
31 | #include <linux/audit.h> | |
19b4946c | 32 | #include <linux/seq_file.h> |
5f921ae9 IM |
33 | #include <linux/mutex.h> |
34 | ||
1da177e4 LT |
35 | #include <asm/current.h> |
36 | #include <asm/uaccess.h> | |
37 | #include "util.h" | |
38 | ||
39 | /* sysctl: */ | |
40 | int msg_ctlmax = MSGMAX; | |
41 | int msg_ctlmnb = MSGMNB; | |
42 | int msg_ctlmni = MSGMNI; | |
43 | ||
44 | /* one msg_receiver structure for each sleeping receiver */ | |
45 | struct msg_receiver { | |
46 | struct list_head r_list; | |
47 | struct task_struct* r_tsk; | |
48 | ||
49 | int r_mode; | |
50 | long r_msgtype; | |
51 | long r_maxsize; | |
52 | ||
53 | struct msg_msg* volatile r_msg; | |
54 | }; | |
55 | ||
56 | /* one msg_sender for each sleeping sender */ | |
57 | struct msg_sender { | |
58 | struct list_head list; | |
59 | struct task_struct* tsk; | |
60 | }; | |
61 | ||
62 | #define SEARCH_ANY 1 | |
63 | #define SEARCH_EQUAL 2 | |
64 | #define SEARCH_NOTEQUAL 3 | |
65 | #define SEARCH_LESSEQUAL 4 | |
66 | ||
67 | static atomic_t msg_bytes = ATOMIC_INIT(0); | |
68 | static atomic_t msg_hdrs = ATOMIC_INIT(0); | |
69 | ||
70 | static struct ipc_ids msg_ids; | |
71 | ||
72 | #define msg_lock(id) ((struct msg_queue*)ipc_lock(&msg_ids,id)) | |
73 | #define msg_unlock(msq) ipc_unlock(&(msq)->q_perm) | |
74 | #define msg_rmid(id) ((struct msg_queue*)ipc_rmid(&msg_ids,id)) | |
75 | #define msg_checkid(msq, msgid) \ | |
76 | ipc_checkid(&msg_ids,&msq->q_perm,msgid) | |
77 | #define msg_buildid(id, seq) \ | |
78 | ipc_buildid(&msg_ids, id, seq) | |
79 | ||
80 | static void freeque (struct msg_queue *msq, int id); | |
81 | static int newque (key_t key, int msgflg); | |
82 | #ifdef CONFIG_PROC_FS | |
19b4946c | 83 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it); |
1da177e4 LT |
84 | #endif |
85 | ||
86 | void __init msg_init (void) | |
87 | { | |
88 | ipc_init_ids(&msg_ids,msg_ctlmni); | |
19b4946c MW |
89 | ipc_init_proc_interface("sysvipc/msg", |
90 | " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", | |
91 | &msg_ids, | |
92 | sysvipc_msg_proc_show); | |
1da177e4 LT |
93 | } |
94 | ||
95 | static int newque (key_t key, int msgflg) | |
96 | { | |
97 | int id; | |
98 | int retval; | |
99 | struct msg_queue *msq; | |
100 | ||
101 | msq = ipc_rcu_alloc(sizeof(*msq)); | |
102 | if (!msq) | |
103 | return -ENOMEM; | |
104 | ||
105 | msq->q_perm.mode = (msgflg & S_IRWXUGO); | |
106 | msq->q_perm.key = key; | |
107 | ||
108 | msq->q_perm.security = NULL; | |
109 | retval = security_msg_queue_alloc(msq); | |
110 | if (retval) { | |
111 | ipc_rcu_putref(msq); | |
112 | return retval; | |
113 | } | |
114 | ||
115 | id = ipc_addid(&msg_ids, &msq->q_perm, msg_ctlmni); | |
116 | if(id == -1) { | |
117 | security_msg_queue_free(msq); | |
118 | ipc_rcu_putref(msq); | |
119 | return -ENOSPC; | |
120 | } | |
121 | ||
19b4946c | 122 | msq->q_id = msg_buildid(id,msq->q_perm.seq); |
1da177e4 LT |
123 | msq->q_stime = msq->q_rtime = 0; |
124 | msq->q_ctime = get_seconds(); | |
125 | msq->q_cbytes = msq->q_qnum = 0; | |
126 | msq->q_qbytes = msg_ctlmnb; | |
127 | msq->q_lspid = msq->q_lrpid = 0; | |
128 | INIT_LIST_HEAD(&msq->q_messages); | |
129 | INIT_LIST_HEAD(&msq->q_receivers); | |
130 | INIT_LIST_HEAD(&msq->q_senders); | |
131 | msg_unlock(msq); | |
132 | ||
19b4946c | 133 | return msq->q_id; |
1da177e4 LT |
134 | } |
135 | ||
136 | static inline void ss_add(struct msg_queue* msq, struct msg_sender* mss) | |
137 | { | |
138 | mss->tsk=current; | |
139 | current->state=TASK_INTERRUPTIBLE; | |
140 | list_add_tail(&mss->list,&msq->q_senders); | |
141 | } | |
142 | ||
143 | static inline void ss_del(struct msg_sender* mss) | |
144 | { | |
145 | if(mss->list.next != NULL) | |
146 | list_del(&mss->list); | |
147 | } | |
148 | ||
149 | static void ss_wakeup(struct list_head* h, int kill) | |
150 | { | |
151 | struct list_head *tmp; | |
152 | ||
153 | tmp = h->next; | |
154 | while (tmp != h) { | |
155 | struct msg_sender* mss; | |
156 | ||
157 | mss = list_entry(tmp,struct msg_sender,list); | |
158 | tmp = tmp->next; | |
159 | if(kill) | |
160 | mss->list.next=NULL; | |
161 | wake_up_process(mss->tsk); | |
162 | } | |
163 | } | |
164 | ||
165 | static void expunge_all(struct msg_queue* msq, int res) | |
166 | { | |
167 | struct list_head *tmp; | |
168 | ||
169 | tmp = msq->q_receivers.next; | |
170 | while (tmp != &msq->q_receivers) { | |
171 | struct msg_receiver* msr; | |
172 | ||
173 | msr = list_entry(tmp,struct msg_receiver,r_list); | |
174 | tmp = tmp->next; | |
175 | msr->r_msg = NULL; | |
176 | wake_up_process(msr->r_tsk); | |
177 | smp_mb(); | |
178 | msr->r_msg = ERR_PTR(res); | |
179 | } | |
180 | } | |
181 | /* | |
182 | * freeque() wakes up waiters on the sender and receiver waiting queue, | |
183 | * removes the message queue from message queue ID | |
184 | * array, and cleans up all the messages associated with this queue. | |
185 | * | |
5f921ae9 IM |
186 | * msg_ids.mutex and the spinlock for this message queue is hold |
187 | * before freeque() is called. msg_ids.mutex remains locked on exit. | |
1da177e4 LT |
188 | */ |
189 | static void freeque (struct msg_queue *msq, int id) | |
190 | { | |
191 | struct list_head *tmp; | |
192 | ||
193 | expunge_all(msq,-EIDRM); | |
194 | ss_wakeup(&msq->q_senders,1); | |
195 | msq = msg_rmid(id); | |
196 | msg_unlock(msq); | |
197 | ||
198 | tmp = msq->q_messages.next; | |
199 | while(tmp != &msq->q_messages) { | |
200 | struct msg_msg* msg = list_entry(tmp,struct msg_msg,m_list); | |
201 | tmp = tmp->next; | |
202 | atomic_dec(&msg_hdrs); | |
203 | free_msg(msg); | |
204 | } | |
205 | atomic_sub(msq->q_cbytes, &msg_bytes); | |
206 | security_msg_queue_free(msq); | |
207 | ipc_rcu_putref(msq); | |
208 | } | |
209 | ||
210 | asmlinkage long sys_msgget (key_t key, int msgflg) | |
211 | { | |
212 | int id, ret = -EPERM; | |
213 | struct msg_queue *msq; | |
214 | ||
5f921ae9 | 215 | mutex_lock(&msg_ids.mutex); |
1da177e4 LT |
216 | if (key == IPC_PRIVATE) |
217 | ret = newque(key, msgflg); | |
218 | else if ((id = ipc_findkey(&msg_ids, key)) == -1) { /* key not used */ | |
219 | if (!(msgflg & IPC_CREAT)) | |
220 | ret = -ENOENT; | |
221 | else | |
222 | ret = newque(key, msgflg); | |
223 | } else if (msgflg & IPC_CREAT && msgflg & IPC_EXCL) { | |
224 | ret = -EEXIST; | |
225 | } else { | |
226 | msq = msg_lock(id); | |
8cd5283b | 227 | BUG_ON(msq==NULL); |
1da177e4 LT |
228 | if (ipcperms(&msq->q_perm, msgflg)) |
229 | ret = -EACCES; | |
230 | else { | |
231 | int qid = msg_buildid(id, msq->q_perm.seq); | |
232 | ret = security_msg_queue_associate(msq, msgflg); | |
233 | if (!ret) | |
234 | ret = qid; | |
235 | } | |
236 | msg_unlock(msq); | |
237 | } | |
5f921ae9 | 238 | mutex_unlock(&msg_ids.mutex); |
1da177e4 LT |
239 | return ret; |
240 | } | |
241 | ||
242 | static inline unsigned long copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version) | |
243 | { | |
244 | switch(version) { | |
245 | case IPC_64: | |
246 | return copy_to_user (buf, in, sizeof(*in)); | |
247 | case IPC_OLD: | |
248 | { | |
249 | struct msqid_ds out; | |
250 | ||
251 | memset(&out,0,sizeof(out)); | |
252 | ||
253 | ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm); | |
254 | ||
255 | out.msg_stime = in->msg_stime; | |
256 | out.msg_rtime = in->msg_rtime; | |
257 | out.msg_ctime = in->msg_ctime; | |
258 | ||
259 | if(in->msg_cbytes > USHRT_MAX) | |
260 | out.msg_cbytes = USHRT_MAX; | |
261 | else | |
262 | out.msg_cbytes = in->msg_cbytes; | |
263 | out.msg_lcbytes = in->msg_cbytes; | |
264 | ||
265 | if(in->msg_qnum > USHRT_MAX) | |
266 | out.msg_qnum = USHRT_MAX; | |
267 | else | |
268 | out.msg_qnum = in->msg_qnum; | |
269 | ||
270 | if(in->msg_qbytes > USHRT_MAX) | |
271 | out.msg_qbytes = USHRT_MAX; | |
272 | else | |
273 | out.msg_qbytes = in->msg_qbytes; | |
274 | out.msg_lqbytes = in->msg_qbytes; | |
275 | ||
276 | out.msg_lspid = in->msg_lspid; | |
277 | out.msg_lrpid = in->msg_lrpid; | |
278 | ||
279 | return copy_to_user (buf, &out, sizeof(out)); | |
280 | } | |
281 | default: | |
282 | return -EINVAL; | |
283 | } | |
284 | } | |
285 | ||
286 | struct msq_setbuf { | |
287 | unsigned long qbytes; | |
288 | uid_t uid; | |
289 | gid_t gid; | |
290 | mode_t mode; | |
291 | }; | |
292 | ||
293 | static inline unsigned long copy_msqid_from_user(struct msq_setbuf *out, void __user *buf, int version) | |
294 | { | |
295 | switch(version) { | |
296 | case IPC_64: | |
297 | { | |
298 | struct msqid64_ds tbuf; | |
299 | ||
300 | if (copy_from_user (&tbuf, buf, sizeof (tbuf))) | |
301 | return -EFAULT; | |
302 | ||
303 | out->qbytes = tbuf.msg_qbytes; | |
304 | out->uid = tbuf.msg_perm.uid; | |
305 | out->gid = tbuf.msg_perm.gid; | |
306 | out->mode = tbuf.msg_perm.mode; | |
307 | ||
308 | return 0; | |
309 | } | |
310 | case IPC_OLD: | |
311 | { | |
312 | struct msqid_ds tbuf_old; | |
313 | ||
314 | if (copy_from_user (&tbuf_old, buf, sizeof (tbuf_old))) | |
315 | return -EFAULT; | |
316 | ||
317 | out->uid = tbuf_old.msg_perm.uid; | |
318 | out->gid = tbuf_old.msg_perm.gid; | |
319 | out->mode = tbuf_old.msg_perm.mode; | |
320 | ||
321 | if(tbuf_old.msg_qbytes == 0) | |
322 | out->qbytes = tbuf_old.msg_lqbytes; | |
323 | else | |
324 | out->qbytes = tbuf_old.msg_qbytes; | |
325 | ||
326 | return 0; | |
327 | } | |
328 | default: | |
329 | return -EINVAL; | |
330 | } | |
331 | } | |
332 | ||
333 | asmlinkage long sys_msgctl (int msqid, int cmd, struct msqid_ds __user *buf) | |
334 | { | |
335 | int err, version; | |
336 | struct msg_queue *msq; | |
337 | struct msq_setbuf setbuf; | |
338 | struct kern_ipc_perm *ipcp; | |
339 | ||
340 | if (msqid < 0 || cmd < 0) | |
341 | return -EINVAL; | |
342 | ||
343 | version = ipc_parse_version(&cmd); | |
344 | ||
345 | switch (cmd) { | |
346 | case IPC_INFO: | |
347 | case MSG_INFO: | |
348 | { | |
349 | struct msginfo msginfo; | |
350 | int max_id; | |
351 | if (!buf) | |
352 | return -EFAULT; | |
353 | /* We must not return kernel stack data. | |
354 | * due to padding, it's not enough | |
355 | * to set all member fields. | |
356 | */ | |
357 | ||
358 | err = security_msg_queue_msgctl(NULL, cmd); | |
359 | if (err) | |
360 | return err; | |
361 | ||
362 | memset(&msginfo,0,sizeof(msginfo)); | |
363 | msginfo.msgmni = msg_ctlmni; | |
364 | msginfo.msgmax = msg_ctlmax; | |
365 | msginfo.msgmnb = msg_ctlmnb; | |
366 | msginfo.msgssz = MSGSSZ; | |
367 | msginfo.msgseg = MSGSEG; | |
5f921ae9 | 368 | mutex_lock(&msg_ids.mutex); |
1da177e4 LT |
369 | if (cmd == MSG_INFO) { |
370 | msginfo.msgpool = msg_ids.in_use; | |
371 | msginfo.msgmap = atomic_read(&msg_hdrs); | |
372 | msginfo.msgtql = atomic_read(&msg_bytes); | |
373 | } else { | |
374 | msginfo.msgmap = MSGMAP; | |
375 | msginfo.msgpool = MSGPOOL; | |
376 | msginfo.msgtql = MSGTQL; | |
377 | } | |
378 | max_id = msg_ids.max_id; | |
5f921ae9 | 379 | mutex_unlock(&msg_ids.mutex); |
1da177e4 LT |
380 | if (copy_to_user (buf, &msginfo, sizeof(struct msginfo))) |
381 | return -EFAULT; | |
382 | return (max_id < 0) ? 0: max_id; | |
383 | } | |
384 | case MSG_STAT: | |
385 | case IPC_STAT: | |
386 | { | |
387 | struct msqid64_ds tbuf; | |
388 | int success_return; | |
389 | if (!buf) | |
390 | return -EFAULT; | |
391 | if(cmd == MSG_STAT && msqid >= msg_ids.entries->size) | |
392 | return -EINVAL; | |
393 | ||
394 | memset(&tbuf,0,sizeof(tbuf)); | |
395 | ||
396 | msq = msg_lock(msqid); | |
397 | if (msq == NULL) | |
398 | return -EINVAL; | |
399 | ||
400 | if(cmd == MSG_STAT) { | |
401 | success_return = msg_buildid(msqid, msq->q_perm.seq); | |
402 | } else { | |
403 | err = -EIDRM; | |
404 | if (msg_checkid(msq,msqid)) | |
405 | goto out_unlock; | |
406 | success_return = 0; | |
407 | } | |
408 | err = -EACCES; | |
409 | if (ipcperms (&msq->q_perm, S_IRUGO)) | |
410 | goto out_unlock; | |
411 | ||
412 | err = security_msg_queue_msgctl(msq, cmd); | |
413 | if (err) | |
414 | goto out_unlock; | |
415 | ||
416 | kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm); | |
417 | tbuf.msg_stime = msq->q_stime; | |
418 | tbuf.msg_rtime = msq->q_rtime; | |
419 | tbuf.msg_ctime = msq->q_ctime; | |
420 | tbuf.msg_cbytes = msq->q_cbytes; | |
421 | tbuf.msg_qnum = msq->q_qnum; | |
422 | tbuf.msg_qbytes = msq->q_qbytes; | |
423 | tbuf.msg_lspid = msq->q_lspid; | |
424 | tbuf.msg_lrpid = msq->q_lrpid; | |
425 | msg_unlock(msq); | |
426 | if (copy_msqid_to_user(buf, &tbuf, version)) | |
427 | return -EFAULT; | |
428 | return success_return; | |
429 | } | |
430 | case IPC_SET: | |
431 | if (!buf) | |
432 | return -EFAULT; | |
433 | if (copy_msqid_from_user (&setbuf, buf, version)) | |
434 | return -EFAULT; | |
1da177e4 LT |
435 | break; |
436 | case IPC_RMID: | |
437 | break; | |
438 | default: | |
439 | return -EINVAL; | |
440 | } | |
441 | ||
5f921ae9 | 442 | mutex_lock(&msg_ids.mutex); |
1da177e4 LT |
443 | msq = msg_lock(msqid); |
444 | err=-EINVAL; | |
445 | if (msq == NULL) | |
446 | goto out_up; | |
447 | ||
448 | err = -EIDRM; | |
449 | if (msg_checkid(msq,msqid)) | |
450 | goto out_unlock_up; | |
451 | ipcp = &msq->q_perm; | |
073115d6 SG |
452 | |
453 | err = audit_ipc_obj(ipcp); | |
454 | if (err) | |
455 | goto out_unlock_up; | |
ac03221a LK |
456 | if (cmd==IPC_SET) { |
457 | err = audit_ipc_set_perm(setbuf.qbytes, setbuf.uid, setbuf.gid, setbuf.mode); | |
458 | if (err) | |
459 | goto out_unlock_up; | |
460 | } | |
073115d6 | 461 | |
1da177e4 LT |
462 | err = -EPERM; |
463 | if (current->euid != ipcp->cuid && | |
464 | current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN)) | |
465 | /* We _could_ check for CAP_CHOWN above, but we don't */ | |
466 | goto out_unlock_up; | |
467 | ||
468 | err = security_msg_queue_msgctl(msq, cmd); | |
469 | if (err) | |
470 | goto out_unlock_up; | |
471 | ||
472 | switch (cmd) { | |
473 | case IPC_SET: | |
474 | { | |
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: | |
5f921ae9 | 503 | mutex_unlock(&msg_ids.mutex); |
1da177e4 LT |
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 | |
19b4946c | 825 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it) |
1da177e4 | 826 | { |
19b4946c MW |
827 | struct msg_queue *msq = it; |
828 | ||
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); | |
1da177e4 LT |
845 | } |
846 | #endif |