Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/ipc/msg.c | |
5a06a363 | 3 | * Copyright (C) 1992 Krishna Balasubramanian |
1da177e4 LT |
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 | ||
5a06a363 IM |
44 | /* |
45 | * one msg_receiver structure for each sleeping receiver: | |
46 | */ | |
1da177e4 | 47 | struct msg_receiver { |
5a06a363 IM |
48 | struct list_head r_list; |
49 | struct task_struct *r_tsk; | |
1da177e4 | 50 | |
5a06a363 IM |
51 | int r_mode; |
52 | long r_msgtype; | |
53 | long r_maxsize; | |
1da177e4 | 54 | |
5a06a363 | 55 | volatile struct msg_msg *r_msg; |
1da177e4 LT |
56 | }; |
57 | ||
58 | /* one msg_sender for each sleeping sender */ | |
59 | struct msg_sender { | |
5a06a363 IM |
60 | struct list_head list; |
61 | struct task_struct *tsk; | |
1da177e4 LT |
62 | }; |
63 | ||
64 | #define SEARCH_ANY 1 | |
65 | #define SEARCH_EQUAL 2 | |
66 | #define SEARCH_NOTEQUAL 3 | |
67 | #define SEARCH_LESSEQUAL 4 | |
68 | ||
5a06a363 IM |
69 | static atomic_t msg_bytes = ATOMIC_INIT(0); |
70 | static atomic_t msg_hdrs = ATOMIC_INIT(0); | |
1da177e4 LT |
71 | |
72 | static struct ipc_ids msg_ids; | |
73 | ||
5a06a363 IM |
74 | #define msg_lock(id) ((struct msg_queue *)ipc_lock(&msg_ids, id)) |
75 | #define msg_unlock(msq) ipc_unlock(&(msq)->q_perm) | |
76 | #define msg_rmid(id) ((struct msg_queue *)ipc_rmid(&msg_ids, id)) | |
77 | #define msg_checkid(msq, msgid) ipc_checkid(&msg_ids, &msq->q_perm, msgid) | |
78 | #define msg_buildid(id, seq) ipc_buildid(&msg_ids, id, seq) | |
1da177e4 | 79 | |
5a06a363 IM |
80 | static void freeque(struct msg_queue *msq, int id); |
81 | static int newque(key_t key, int msgflg); | |
1da177e4 | 82 | #ifdef CONFIG_PROC_FS |
19b4946c | 83 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it); |
1da177e4 LT |
84 | #endif |
85 | ||
5a06a363 | 86 | void __init msg_init(void) |
1da177e4 | 87 | { |
5a06a363 | 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 | ||
5a06a363 | 95 | static int newque(key_t key, int msgflg) |
1da177e4 | 96 | { |
1da177e4 | 97 | struct msg_queue *msq; |
5a06a363 | 98 | int id, retval; |
1da177e4 | 99 | |
5a06a363 IM |
100 | msq = ipc_rcu_alloc(sizeof(*msq)); |
101 | if (!msq) | |
1da177e4 LT |
102 | return -ENOMEM; |
103 | ||
5a06a363 | 104 | msq->q_perm.mode = msgflg & S_IRWXUGO; |
1da177e4 LT |
105 | msq->q_perm.key = key; |
106 | ||
107 | msq->q_perm.security = NULL; | |
108 | retval = security_msg_queue_alloc(msq); | |
109 | if (retval) { | |
110 | ipc_rcu_putref(msq); | |
111 | return retval; | |
112 | } | |
113 | ||
114 | id = ipc_addid(&msg_ids, &msq->q_perm, msg_ctlmni); | |
5a06a363 | 115 | if (id == -1) { |
1da177e4 LT |
116 | security_msg_queue_free(msq); |
117 | ipc_rcu_putref(msq); | |
118 | return -ENOSPC; | |
119 | } | |
120 | ||
5a06a363 | 121 | msq->q_id = msg_buildid(id, msq->q_perm.seq); |
1da177e4 LT |
122 | msq->q_stime = msq->q_rtime = 0; |
123 | msq->q_ctime = get_seconds(); | |
124 | msq->q_cbytes = msq->q_qnum = 0; | |
125 | msq->q_qbytes = msg_ctlmnb; | |
126 | msq->q_lspid = msq->q_lrpid = 0; | |
127 | INIT_LIST_HEAD(&msq->q_messages); | |
128 | INIT_LIST_HEAD(&msq->q_receivers); | |
129 | INIT_LIST_HEAD(&msq->q_senders); | |
130 | msg_unlock(msq); | |
131 | ||
19b4946c | 132 | return msq->q_id; |
1da177e4 LT |
133 | } |
134 | ||
5a06a363 | 135 | static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss) |
1da177e4 | 136 | { |
5a06a363 IM |
137 | mss->tsk = current; |
138 | current->state = TASK_INTERRUPTIBLE; | |
139 | list_add_tail(&mss->list, &msq->q_senders); | |
1da177e4 LT |
140 | } |
141 | ||
5a06a363 | 142 | static inline void ss_del(struct msg_sender *mss) |
1da177e4 | 143 | { |
5a06a363 | 144 | if (mss->list.next != NULL) |
1da177e4 LT |
145 | list_del(&mss->list); |
146 | } | |
147 | ||
5a06a363 | 148 | static void ss_wakeup(struct list_head *h, int kill) |
1da177e4 LT |
149 | { |
150 | struct list_head *tmp; | |
151 | ||
152 | tmp = h->next; | |
153 | while (tmp != h) { | |
5a06a363 IM |
154 | struct msg_sender *mss; |
155 | ||
156 | mss = list_entry(tmp, struct msg_sender, list); | |
1da177e4 | 157 | tmp = tmp->next; |
5a06a363 IM |
158 | if (kill) |
159 | mss->list.next = NULL; | |
1da177e4 LT |
160 | wake_up_process(mss->tsk); |
161 | } | |
162 | } | |
163 | ||
5a06a363 | 164 | static void expunge_all(struct msg_queue *msq, int res) |
1da177e4 LT |
165 | { |
166 | struct list_head *tmp; | |
167 | ||
168 | tmp = msq->q_receivers.next; | |
169 | while (tmp != &msq->q_receivers) { | |
5a06a363 IM |
170 | struct msg_receiver *msr; |
171 | ||
172 | msr = list_entry(tmp, struct msg_receiver, r_list); | |
1da177e4 LT |
173 | tmp = tmp->next; |
174 | msr->r_msg = NULL; | |
175 | wake_up_process(msr->r_tsk); | |
176 | smp_mb(); | |
177 | msr->r_msg = ERR_PTR(res); | |
178 | } | |
179 | } | |
5a06a363 IM |
180 | |
181 | /* | |
182 | * freeque() wakes up waiters on the sender and receiver waiting queue, | |
183 | * removes the message queue from message queue ID | |
1da177e4 LT |
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 | 188 | */ |
5a06a363 | 189 | static void freeque(struct msg_queue *msq, int id) |
1da177e4 LT |
190 | { |
191 | struct list_head *tmp; | |
192 | ||
5a06a363 IM |
193 | expunge_all(msq, -EIDRM); |
194 | ss_wakeup(&msq->q_senders, 1); | |
1da177e4 LT |
195 | msq = msg_rmid(id); |
196 | msg_unlock(msq); | |
5a06a363 | 197 | |
1da177e4 | 198 | tmp = msq->q_messages.next; |
5a06a363 IM |
199 | while (tmp != &msq->q_messages) { |
200 | struct msg_msg *msg = list_entry(tmp, struct msg_msg, m_list); | |
201 | ||
1da177e4 LT |
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 | ||
5a06a363 | 211 | asmlinkage long sys_msgget(key_t key, int msgflg) |
1da177e4 | 212 | { |
1da177e4 | 213 | struct msg_queue *msq; |
5a06a363 | 214 | int id, ret = -EPERM; |
1da177e4 | 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); | |
5a06a363 | 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); | |
5a06a363 IM |
233 | |
234 | ret = security_msg_queue_associate(msq, msgflg); | |
1da177e4 LT |
235 | if (!ret) |
236 | ret = qid; | |
237 | } | |
238 | msg_unlock(msq); | |
239 | } | |
5f921ae9 | 240 | mutex_unlock(&msg_ids.mutex); |
5a06a363 | 241 | |
1da177e4 LT |
242 | return ret; |
243 | } | |
244 | ||
5a06a363 IM |
245 | static inline unsigned long |
246 | copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version) | |
1da177e4 LT |
247 | { |
248 | switch(version) { | |
249 | case IPC_64: | |
5a06a363 | 250 | return copy_to_user(buf, in, sizeof(*in)); |
1da177e4 | 251 | case IPC_OLD: |
5a06a363 | 252 | { |
1da177e4 LT |
253 | struct msqid_ds out; |
254 | ||
5a06a363 | 255 | memset(&out, 0, sizeof(out)); |
1da177e4 LT |
256 | |
257 | ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm); | |
258 | ||
259 | out.msg_stime = in->msg_stime; | |
260 | out.msg_rtime = in->msg_rtime; | |
261 | out.msg_ctime = in->msg_ctime; | |
262 | ||
5a06a363 | 263 | if (in->msg_cbytes > USHRT_MAX) |
1da177e4 LT |
264 | out.msg_cbytes = USHRT_MAX; |
265 | else | |
266 | out.msg_cbytes = in->msg_cbytes; | |
267 | out.msg_lcbytes = in->msg_cbytes; | |
268 | ||
5a06a363 | 269 | if (in->msg_qnum > USHRT_MAX) |
1da177e4 LT |
270 | out.msg_qnum = USHRT_MAX; |
271 | else | |
272 | out.msg_qnum = in->msg_qnum; | |
273 | ||
5a06a363 | 274 | if (in->msg_qbytes > USHRT_MAX) |
1da177e4 LT |
275 | out.msg_qbytes = USHRT_MAX; |
276 | else | |
277 | out.msg_qbytes = in->msg_qbytes; | |
278 | out.msg_lqbytes = in->msg_qbytes; | |
279 | ||
280 | out.msg_lspid = in->msg_lspid; | |
281 | out.msg_lrpid = in->msg_lrpid; | |
282 | ||
5a06a363 IM |
283 | return copy_to_user(buf, &out, sizeof(out)); |
284 | } | |
1da177e4 LT |
285 | default: |
286 | return -EINVAL; | |
287 | } | |
288 | } | |
289 | ||
290 | struct msq_setbuf { | |
291 | unsigned long qbytes; | |
292 | uid_t uid; | |
293 | gid_t gid; | |
294 | mode_t mode; | |
295 | }; | |
296 | ||
5a06a363 IM |
297 | static inline unsigned long |
298 | copy_msqid_from_user(struct msq_setbuf *out, void __user *buf, int version) | |
1da177e4 LT |
299 | { |
300 | switch(version) { | |
301 | case IPC_64: | |
5a06a363 | 302 | { |
1da177e4 LT |
303 | struct msqid64_ds tbuf; |
304 | ||
5a06a363 | 305 | if (copy_from_user(&tbuf, buf, sizeof(tbuf))) |
1da177e4 LT |
306 | return -EFAULT; |
307 | ||
308 | out->qbytes = tbuf.msg_qbytes; | |
309 | out->uid = tbuf.msg_perm.uid; | |
310 | out->gid = tbuf.msg_perm.gid; | |
311 | out->mode = tbuf.msg_perm.mode; | |
312 | ||
313 | return 0; | |
5a06a363 | 314 | } |
1da177e4 | 315 | case IPC_OLD: |
5a06a363 | 316 | { |
1da177e4 LT |
317 | struct msqid_ds tbuf_old; |
318 | ||
5a06a363 | 319 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) |
1da177e4 LT |
320 | return -EFAULT; |
321 | ||
322 | out->uid = tbuf_old.msg_perm.uid; | |
323 | out->gid = tbuf_old.msg_perm.gid; | |
324 | out->mode = tbuf_old.msg_perm.mode; | |
325 | ||
5a06a363 | 326 | if (tbuf_old.msg_qbytes == 0) |
1da177e4 LT |
327 | out->qbytes = tbuf_old.msg_lqbytes; |
328 | else | |
329 | out->qbytes = tbuf_old.msg_qbytes; | |
330 | ||
331 | return 0; | |
5a06a363 | 332 | } |
1da177e4 LT |
333 | default: |
334 | return -EINVAL; | |
335 | } | |
336 | } | |
337 | ||
5a06a363 | 338 | asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf) |
1da177e4 | 339 | { |
1da177e4 | 340 | struct kern_ipc_perm *ipcp; |
5a06a363 IM |
341 | struct msq_setbuf setbuf; |
342 | struct msg_queue *msq; | |
343 | int err, version; | |
344 | ||
1da177e4 LT |
345 | if (msqid < 0 || cmd < 0) |
346 | return -EINVAL; | |
347 | ||
348 | version = ipc_parse_version(&cmd); | |
349 | ||
350 | switch (cmd) { | |
5a06a363 IM |
351 | case IPC_INFO: |
352 | case MSG_INFO: | |
353 | { | |
1da177e4 LT |
354 | struct msginfo msginfo; |
355 | int max_id; | |
5a06a363 | 356 | |
1da177e4 LT |
357 | if (!buf) |
358 | return -EFAULT; | |
5a06a363 IM |
359 | /* |
360 | * We must not return kernel stack data. | |
1da177e4 LT |
361 | * due to padding, it's not enough |
362 | * to set all member fields. | |
363 | */ | |
1da177e4 LT |
364 | err = security_msg_queue_msgctl(NULL, cmd); |
365 | if (err) | |
366 | return err; | |
367 | ||
5a06a363 | 368 | memset(&msginfo, 0, sizeof(msginfo)); |
1da177e4 LT |
369 | msginfo.msgmni = msg_ctlmni; |
370 | msginfo.msgmax = msg_ctlmax; | |
371 | msginfo.msgmnb = msg_ctlmnb; | |
372 | msginfo.msgssz = MSGSSZ; | |
373 | msginfo.msgseg = MSGSEG; | |
5f921ae9 | 374 | mutex_lock(&msg_ids.mutex); |
1da177e4 LT |
375 | if (cmd == MSG_INFO) { |
376 | msginfo.msgpool = msg_ids.in_use; | |
377 | msginfo.msgmap = atomic_read(&msg_hdrs); | |
378 | msginfo.msgtql = atomic_read(&msg_bytes); | |
379 | } else { | |
380 | msginfo.msgmap = MSGMAP; | |
381 | msginfo.msgpool = MSGPOOL; | |
382 | msginfo.msgtql = MSGTQL; | |
383 | } | |
384 | max_id = msg_ids.max_id; | |
5f921ae9 | 385 | mutex_unlock(&msg_ids.mutex); |
5a06a363 | 386 | if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) |
1da177e4 | 387 | return -EFAULT; |
5a06a363 | 388 | return (max_id < 0) ? 0 : max_id; |
1da177e4 LT |
389 | } |
390 | case MSG_STAT: | |
391 | case IPC_STAT: | |
392 | { | |
393 | struct msqid64_ds tbuf; | |
394 | int success_return; | |
5a06a363 | 395 | |
1da177e4 LT |
396 | if (!buf) |
397 | return -EFAULT; | |
5a06a363 | 398 | if (cmd == MSG_STAT && msqid >= msg_ids.entries->size) |
1da177e4 LT |
399 | return -EINVAL; |
400 | ||
5a06a363 | 401 | memset(&tbuf, 0, sizeof(tbuf)); |
1da177e4 LT |
402 | |
403 | msq = msg_lock(msqid); | |
404 | if (msq == NULL) | |
405 | return -EINVAL; | |
406 | ||
5a06a363 | 407 | if (cmd == MSG_STAT) { |
1da177e4 LT |
408 | success_return = msg_buildid(msqid, msq->q_perm.seq); |
409 | } else { | |
410 | err = -EIDRM; | |
5a06a363 | 411 | if (msg_checkid(msq, msqid)) |
1da177e4 LT |
412 | goto out_unlock; |
413 | success_return = 0; | |
414 | } | |
415 | err = -EACCES; | |
5a06a363 | 416 | if (ipcperms(&msq->q_perm, S_IRUGO)) |
1da177e4 LT |
417 | goto out_unlock; |
418 | ||
419 | err = security_msg_queue_msgctl(msq, cmd); | |
420 | if (err) | |
421 | goto out_unlock; | |
422 | ||
423 | kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm); | |
424 | tbuf.msg_stime = msq->q_stime; | |
425 | tbuf.msg_rtime = msq->q_rtime; | |
426 | tbuf.msg_ctime = msq->q_ctime; | |
427 | tbuf.msg_cbytes = msq->q_cbytes; | |
428 | tbuf.msg_qnum = msq->q_qnum; | |
429 | tbuf.msg_qbytes = msq->q_qbytes; | |
430 | tbuf.msg_lspid = msq->q_lspid; | |
431 | tbuf.msg_lrpid = msq->q_lrpid; | |
432 | msg_unlock(msq); | |
433 | if (copy_msqid_to_user(buf, &tbuf, version)) | |
434 | return -EFAULT; | |
435 | return success_return; | |
436 | } | |
437 | case IPC_SET: | |
438 | if (!buf) | |
439 | return -EFAULT; | |
5a06a363 | 440 | if (copy_msqid_from_user(&setbuf, buf, version)) |
1da177e4 | 441 | return -EFAULT; |
1da177e4 LT |
442 | break; |
443 | case IPC_RMID: | |
444 | break; | |
445 | default: | |
446 | return -EINVAL; | |
447 | } | |
448 | ||
5f921ae9 | 449 | mutex_lock(&msg_ids.mutex); |
1da177e4 | 450 | msq = msg_lock(msqid); |
5a06a363 | 451 | err = -EINVAL; |
1da177e4 LT |
452 | if (msq == NULL) |
453 | goto out_up; | |
454 | ||
455 | err = -EIDRM; | |
5a06a363 | 456 | if (msg_checkid(msq, msqid)) |
1da177e4 LT |
457 | goto out_unlock_up; |
458 | ipcp = &msq->q_perm; | |
073115d6 SG |
459 | |
460 | err = audit_ipc_obj(ipcp); | |
461 | if (err) | |
462 | goto out_unlock_up; | |
ac03221a | 463 | if (cmd==IPC_SET) { |
5a06a363 IM |
464 | err = audit_ipc_set_perm(setbuf.qbytes, setbuf.uid, setbuf.gid, |
465 | setbuf.mode); | |
ac03221a LK |
466 | if (err) |
467 | goto out_unlock_up; | |
468 | } | |
073115d6 | 469 | |
1da177e4 | 470 | err = -EPERM; |
5a06a363 | 471 | if (current->euid != ipcp->cuid && |
1da177e4 | 472 | current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN)) |
5a06a363 | 473 | /* We _could_ check for CAP_CHOWN above, but we don't */ |
1da177e4 LT |
474 | goto out_unlock_up; |
475 | ||
476 | err = security_msg_queue_msgctl(msq, cmd); | |
477 | if (err) | |
478 | goto out_unlock_up; | |
479 | ||
480 | switch (cmd) { | |
481 | case IPC_SET: | |
482 | { | |
483 | err = -EPERM; | |
484 | if (setbuf.qbytes > msg_ctlmnb && !capable(CAP_SYS_RESOURCE)) | |
485 | goto out_unlock_up; | |
486 | ||
487 | msq->q_qbytes = setbuf.qbytes; | |
488 | ||
489 | ipcp->uid = setbuf.uid; | |
490 | ipcp->gid = setbuf.gid; | |
5a06a363 IM |
491 | ipcp->mode = (ipcp->mode & ~S_IRWXUGO) | |
492 | (S_IRWXUGO & setbuf.mode); | |
1da177e4 LT |
493 | msq->q_ctime = get_seconds(); |
494 | /* sleeping receivers might be excluded by | |
495 | * stricter permissions. | |
496 | */ | |
5a06a363 | 497 | expunge_all(msq, -EAGAIN); |
1da177e4 LT |
498 | /* sleeping senders might be able to send |
499 | * due to a larger queue size. | |
500 | */ | |
5a06a363 | 501 | ss_wakeup(&msq->q_senders, 0); |
1da177e4 LT |
502 | msg_unlock(msq); |
503 | break; | |
504 | } | |
505 | case IPC_RMID: | |
5a06a363 | 506 | freeque(msq, msqid); |
1da177e4 LT |
507 | break; |
508 | } | |
509 | err = 0; | |
510 | out_up: | |
5f921ae9 | 511 | mutex_unlock(&msg_ids.mutex); |
1da177e4 LT |
512 | return err; |
513 | out_unlock_up: | |
514 | msg_unlock(msq); | |
515 | goto out_up; | |
516 | out_unlock: | |
517 | msg_unlock(msq); | |
518 | return err; | |
519 | } | |
520 | ||
5a06a363 | 521 | static int testmsg(struct msg_msg *msg, long type, int mode) |
1da177e4 LT |
522 | { |
523 | switch(mode) | |
524 | { | |
525 | case SEARCH_ANY: | |
526 | return 1; | |
527 | case SEARCH_LESSEQUAL: | |
5a06a363 | 528 | if (msg->m_type <=type) |
1da177e4 LT |
529 | return 1; |
530 | break; | |
531 | case SEARCH_EQUAL: | |
5a06a363 | 532 | if (msg->m_type == type) |
1da177e4 LT |
533 | return 1; |
534 | break; | |
535 | case SEARCH_NOTEQUAL: | |
5a06a363 | 536 | if (msg->m_type != type) |
1da177e4 LT |
537 | return 1; |
538 | break; | |
539 | } | |
540 | return 0; | |
541 | } | |
542 | ||
5a06a363 | 543 | static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg) |
1da177e4 | 544 | { |
5a06a363 | 545 | struct list_head *tmp; |
1da177e4 LT |
546 | |
547 | tmp = msq->q_receivers.next; | |
548 | while (tmp != &msq->q_receivers) { | |
5a06a363 IM |
549 | struct msg_receiver *msr; |
550 | ||
551 | msr = list_entry(tmp, struct msg_receiver, r_list); | |
1da177e4 | 552 | tmp = tmp->next; |
5a06a363 IM |
553 | if (testmsg(msg, msr->r_msgtype, msr->r_mode) && |
554 | !security_msg_queue_msgrcv(msq, msg, msr->r_tsk, | |
555 | msr->r_msgtype, msr->r_mode)) { | |
556 | ||
1da177e4 | 557 | list_del(&msr->r_list); |
5a06a363 | 558 | if (msr->r_maxsize < msg->m_ts) { |
1da177e4 LT |
559 | msr->r_msg = NULL; |
560 | wake_up_process(msr->r_tsk); | |
561 | smp_mb(); | |
562 | msr->r_msg = ERR_PTR(-E2BIG); | |
563 | } else { | |
564 | msr->r_msg = NULL; | |
565 | msq->q_lrpid = msr->r_tsk->pid; | |
566 | msq->q_rtime = get_seconds(); | |
567 | wake_up_process(msr->r_tsk); | |
568 | smp_mb(); | |
569 | msr->r_msg = msg; | |
5a06a363 | 570 | |
1da177e4 LT |
571 | return 1; |
572 | } | |
573 | } | |
574 | } | |
575 | return 0; | |
576 | } | |
577 | ||
5a06a363 IM |
578 | asmlinkage long |
579 | sys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz, int msgflg) | |
1da177e4 LT |
580 | { |
581 | struct msg_queue *msq; | |
582 | struct msg_msg *msg; | |
583 | long mtype; | |
584 | int err; | |
5a06a363 | 585 | |
1da177e4 LT |
586 | if (msgsz > msg_ctlmax || (long) msgsz < 0 || msqid < 0) |
587 | return -EINVAL; | |
588 | if (get_user(mtype, &msgp->mtype)) | |
5a06a363 | 589 | return -EFAULT; |
1da177e4 LT |
590 | if (mtype < 1) |
591 | return -EINVAL; | |
592 | ||
593 | msg = load_msg(msgp->mtext, msgsz); | |
5a06a363 | 594 | if (IS_ERR(msg)) |
1da177e4 LT |
595 | return PTR_ERR(msg); |
596 | ||
597 | msg->m_type = mtype; | |
598 | msg->m_ts = msgsz; | |
599 | ||
600 | msq = msg_lock(msqid); | |
5a06a363 IM |
601 | err = -EINVAL; |
602 | if (msq == NULL) | |
1da177e4 LT |
603 | goto out_free; |
604 | ||
605 | err= -EIDRM; | |
5a06a363 | 606 | if (msg_checkid(msq, msqid)) |
1da177e4 LT |
607 | goto out_unlock_free; |
608 | ||
609 | for (;;) { | |
610 | struct msg_sender s; | |
611 | ||
5a06a363 | 612 | err = -EACCES; |
1da177e4 LT |
613 | if (ipcperms(&msq->q_perm, S_IWUGO)) |
614 | goto out_unlock_free; | |
615 | ||
616 | err = security_msg_queue_msgsnd(msq, msg, msgflg); | |
617 | if (err) | |
618 | goto out_unlock_free; | |
619 | ||
5a06a363 | 620 | if (msgsz + msq->q_cbytes <= msq->q_qbytes && |
1da177e4 LT |
621 | 1 + msq->q_qnum <= msq->q_qbytes) { |
622 | break; | |
623 | } | |
624 | ||
625 | /* queue full, wait: */ | |
5a06a363 IM |
626 | if (msgflg & IPC_NOWAIT) { |
627 | err = -EAGAIN; | |
1da177e4 LT |
628 | goto out_unlock_free; |
629 | } | |
630 | ss_add(msq, &s); | |
631 | ipc_rcu_getref(msq); | |
632 | msg_unlock(msq); | |
633 | schedule(); | |
634 | ||
635 | ipc_lock_by_ptr(&msq->q_perm); | |
636 | ipc_rcu_putref(msq); | |
637 | if (msq->q_perm.deleted) { | |
638 | err = -EIDRM; | |
639 | goto out_unlock_free; | |
640 | } | |
641 | ss_del(&s); | |
5a06a363 | 642 | |
1da177e4 | 643 | if (signal_pending(current)) { |
5a06a363 | 644 | err = -ERESTARTNOHAND; |
1da177e4 LT |
645 | goto out_unlock_free; |
646 | } | |
647 | } | |
648 | ||
649 | msq->q_lspid = current->tgid; | |
650 | msq->q_stime = get_seconds(); | |
651 | ||
5a06a363 | 652 | if (!pipelined_send(msq, msg)) { |
1da177e4 | 653 | /* noone is waiting for this message, enqueue it */ |
5a06a363 | 654 | list_add_tail(&msg->m_list, &msq->q_messages); |
1da177e4 LT |
655 | msq->q_cbytes += msgsz; |
656 | msq->q_qnum++; | |
5a06a363 | 657 | atomic_add(msgsz, &msg_bytes); |
1da177e4 LT |
658 | atomic_inc(&msg_hdrs); |
659 | } | |
5a06a363 | 660 | |
1da177e4 LT |
661 | err = 0; |
662 | msg = NULL; | |
663 | ||
664 | out_unlock_free: | |
665 | msg_unlock(msq); | |
666 | out_free: | |
5a06a363 | 667 | if (msg != NULL) |
1da177e4 LT |
668 | free_msg(msg); |
669 | return err; | |
670 | } | |
671 | ||
5a06a363 | 672 | static inline int convert_mode(long *msgtyp, int msgflg) |
1da177e4 | 673 | { |
5a06a363 | 674 | /* |
1da177e4 LT |
675 | * find message of correct type. |
676 | * msgtyp = 0 => get first. | |
677 | * msgtyp > 0 => get first message of matching type. | |
5a06a363 | 678 | * msgtyp < 0 => get message with least type must be < abs(msgtype). |
1da177e4 | 679 | */ |
5a06a363 | 680 | if (*msgtyp == 0) |
1da177e4 | 681 | return SEARCH_ANY; |
5a06a363 IM |
682 | if (*msgtyp < 0) { |
683 | *msgtyp = -*msgtyp; | |
1da177e4 LT |
684 | return SEARCH_LESSEQUAL; |
685 | } | |
5a06a363 | 686 | if (msgflg & MSG_EXCEPT) |
1da177e4 LT |
687 | return SEARCH_NOTEQUAL; |
688 | return SEARCH_EQUAL; | |
689 | } | |
690 | ||
5a06a363 IM |
691 | asmlinkage long sys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz, |
692 | long msgtyp, int msgflg) | |
1da177e4 LT |
693 | { |
694 | struct msg_queue *msq; | |
695 | struct msg_msg *msg; | |
696 | int mode; | |
697 | ||
698 | if (msqid < 0 || (long) msgsz < 0) | |
699 | return -EINVAL; | |
5a06a363 | 700 | mode = convert_mode(&msgtyp, msgflg); |
1da177e4 LT |
701 | |
702 | msq = msg_lock(msqid); | |
5a06a363 | 703 | if (msq == NULL) |
1da177e4 LT |
704 | return -EINVAL; |
705 | ||
706 | msg = ERR_PTR(-EIDRM); | |
5a06a363 | 707 | if (msg_checkid(msq, msqid)) |
1da177e4 LT |
708 | goto out_unlock; |
709 | ||
710 | for (;;) { | |
711 | struct msg_receiver msr_d; | |
5a06a363 | 712 | struct list_head *tmp; |
1da177e4 LT |
713 | |
714 | msg = ERR_PTR(-EACCES); | |
5a06a363 | 715 | if (ipcperms(&msq->q_perm, S_IRUGO)) |
1da177e4 LT |
716 | goto out_unlock; |
717 | ||
718 | msg = ERR_PTR(-EAGAIN); | |
719 | tmp = msq->q_messages.next; | |
720 | while (tmp != &msq->q_messages) { | |
721 | struct msg_msg *walk_msg; | |
5a06a363 IM |
722 | |
723 | walk_msg = list_entry(tmp, struct msg_msg, m_list); | |
724 | if (testmsg(walk_msg, msgtyp, mode) && | |
725 | !security_msg_queue_msgrcv(msq, walk_msg, current, | |
726 | msgtyp, mode)) { | |
727 | ||
1da177e4 | 728 | msg = walk_msg; |
5a06a363 IM |
729 | if (mode == SEARCH_LESSEQUAL && |
730 | walk_msg->m_type != 1) { | |
731 | msg = walk_msg; | |
732 | msgtyp = walk_msg->m_type - 1; | |
1da177e4 | 733 | } else { |
5a06a363 | 734 | msg = walk_msg; |
1da177e4 LT |
735 | break; |
736 | } | |
737 | } | |
738 | tmp = tmp->next; | |
739 | } | |
5a06a363 IM |
740 | if (!IS_ERR(msg)) { |
741 | /* | |
742 | * Found a suitable message. | |
743 | * Unlink it from the queue. | |
744 | */ | |
1da177e4 LT |
745 | if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { |
746 | msg = ERR_PTR(-E2BIG); | |
747 | goto out_unlock; | |
748 | } | |
749 | list_del(&msg->m_list); | |
750 | msq->q_qnum--; | |
751 | msq->q_rtime = get_seconds(); | |
752 | msq->q_lrpid = current->tgid; | |
753 | msq->q_cbytes -= msg->m_ts; | |
5a06a363 | 754 | atomic_sub(msg->m_ts, &msg_bytes); |
1da177e4 | 755 | atomic_dec(&msg_hdrs); |
5a06a363 | 756 | ss_wakeup(&msq->q_senders, 0); |
1da177e4 LT |
757 | msg_unlock(msq); |
758 | break; | |
759 | } | |
760 | /* No message waiting. Wait for a message */ | |
761 | if (msgflg & IPC_NOWAIT) { | |
762 | msg = ERR_PTR(-ENOMSG); | |
763 | goto out_unlock; | |
764 | } | |
5a06a363 | 765 | list_add_tail(&msr_d.r_list, &msq->q_receivers); |
1da177e4 LT |
766 | msr_d.r_tsk = current; |
767 | msr_d.r_msgtype = msgtyp; | |
768 | msr_d.r_mode = mode; | |
5a06a363 | 769 | if (msgflg & MSG_NOERROR) |
1da177e4 | 770 | msr_d.r_maxsize = INT_MAX; |
5a06a363 | 771 | else |
1da177e4 LT |
772 | msr_d.r_maxsize = msgsz; |
773 | msr_d.r_msg = ERR_PTR(-EAGAIN); | |
774 | current->state = TASK_INTERRUPTIBLE; | |
775 | msg_unlock(msq); | |
776 | ||
777 | schedule(); | |
778 | ||
779 | /* Lockless receive, part 1: | |
780 | * Disable preemption. We don't hold a reference to the queue | |
781 | * and getting a reference would defeat the idea of a lockless | |
782 | * operation, thus the code relies on rcu to guarantee the | |
783 | * existance of msq: | |
784 | * Prior to destruction, expunge_all(-EIRDM) changes r_msg. | |
785 | * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. | |
786 | * rcu_read_lock() prevents preemption between reading r_msg | |
787 | * and the spin_lock() inside ipc_lock_by_ptr(). | |
788 | */ | |
789 | rcu_read_lock(); | |
790 | ||
791 | /* Lockless receive, part 2: | |
792 | * Wait until pipelined_send or expunge_all are outside of | |
793 | * wake_up_process(). There is a race with exit(), see | |
794 | * ipc/mqueue.c for the details. | |
795 | */ | |
5a06a363 | 796 | msg = (struct msg_msg*)msr_d.r_msg; |
1da177e4 LT |
797 | while (msg == NULL) { |
798 | cpu_relax(); | |
5a06a363 | 799 | msg = (struct msg_msg *)msr_d.r_msg; |
1da177e4 LT |
800 | } |
801 | ||
802 | /* Lockless receive, part 3: | |
803 | * If there is a message or an error then accept it without | |
804 | * locking. | |
805 | */ | |
5a06a363 | 806 | if (msg != ERR_PTR(-EAGAIN)) { |
1da177e4 LT |
807 | rcu_read_unlock(); |
808 | break; | |
809 | } | |
810 | ||
811 | /* Lockless receive, part 3: | |
812 | * Acquire the queue spinlock. | |
813 | */ | |
814 | ipc_lock_by_ptr(&msq->q_perm); | |
815 | rcu_read_unlock(); | |
816 | ||
817 | /* Lockless receive, part 4: | |
818 | * Repeat test after acquiring the spinlock. | |
819 | */ | |
820 | msg = (struct msg_msg*)msr_d.r_msg; | |
5a06a363 | 821 | if (msg != ERR_PTR(-EAGAIN)) |
1da177e4 LT |
822 | goto out_unlock; |
823 | ||
824 | list_del(&msr_d.r_list); | |
825 | if (signal_pending(current)) { | |
826 | msg = ERR_PTR(-ERESTARTNOHAND); | |
827 | out_unlock: | |
828 | msg_unlock(msq); | |
829 | break; | |
830 | } | |
831 | } | |
832 | if (IS_ERR(msg)) | |
5a06a363 | 833 | return PTR_ERR(msg); |
1da177e4 LT |
834 | |
835 | msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz; | |
836 | if (put_user (msg->m_type, &msgp->mtype) || | |
837 | store_msg(msgp->mtext, msg, msgsz)) { | |
5a06a363 | 838 | msgsz = -EFAULT; |
1da177e4 LT |
839 | } |
840 | free_msg(msg); | |
5a06a363 | 841 | |
1da177e4 LT |
842 | return msgsz; |
843 | } | |
844 | ||
845 | #ifdef CONFIG_PROC_FS | |
19b4946c | 846 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it) |
1da177e4 | 847 | { |
19b4946c MW |
848 | struct msg_queue *msq = it; |
849 | ||
850 | return seq_printf(s, | |
5a06a363 IM |
851 | "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n", |
852 | msq->q_perm.key, | |
853 | msq->q_id, | |
854 | msq->q_perm.mode, | |
855 | msq->q_cbytes, | |
856 | msq->q_qnum, | |
857 | msq->q_lspid, | |
858 | msq->q_lrpid, | |
859 | msq->q_perm.uid, | |
860 | msq->q_perm.gid, | |
861 | msq->q_perm.cuid, | |
862 | msq->q_perm.cgid, | |
863 | msq->q_stime, | |
864 | msq->q_rtime, | |
865 | msq->q_ctime); | |
1da177e4 LT |
866 | } |
867 | #endif |