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1 | /* | |
2 | * POSIX message queues filesystem for Linux. | |
3 | * | |
4 | * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl) | |
5 | * Michal Wronski (michal.wronski@gmail.com) | |
6 | * | |
7 | * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com) | |
8 | * Lockless receive & send, fd based notify: | |
9 | * Manfred Spraul (manfred@colorfullife.com) | |
10 | * | |
11 | * Audit: George Wilson (ltcgcw@us.ibm.com) | |
12 | * | |
13 | * This file is released under the GPL. | |
14 | */ | |
15 | ||
16 | #include <linux/capability.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/pagemap.h> | |
19 | #include <linux/file.h> | |
20 | #include <linux/mount.h> | |
21 | #include <linux/namei.h> | |
22 | #include <linux/sysctl.h> | |
23 | #include <linux/poll.h> | |
24 | #include <linux/mqueue.h> | |
25 | #include <linux/msg.h> | |
26 | #include <linux/skbuff.h> | |
27 | #include <linux/vmalloc.h> | |
28 | #include <linux/netlink.h> | |
29 | #include <linux/syscalls.h> | |
30 | #include <linux/audit.h> | |
31 | #include <linux/signal.h> | |
32 | #include <linux/mutex.h> | |
33 | #include <linux/nsproxy.h> | |
34 | #include <linux/pid.h> | |
35 | #include <linux/ipc_namespace.h> | |
36 | #include <linux/user_namespace.h> | |
37 | #include <linux/slab.h> | |
38 | ||
39 | #include <net/sock.h> | |
40 | #include "util.h" | |
41 | ||
42 | #define MQUEUE_MAGIC 0x19800202 | |
43 | #define DIRENT_SIZE 20 | |
44 | #define FILENT_SIZE 80 | |
45 | ||
46 | #define SEND 0 | |
47 | #define RECV 1 | |
48 | ||
49 | #define STATE_NONE 0 | |
50 | #define STATE_READY 1 | |
51 | ||
52 | struct posix_msg_tree_node { | |
53 | struct rb_node rb_node; | |
54 | struct list_head msg_list; | |
55 | int priority; | |
56 | }; | |
57 | ||
58 | struct ext_wait_queue { /* queue of sleeping tasks */ | |
59 | struct task_struct *task; | |
60 | struct list_head list; | |
61 | struct msg_msg *msg; /* ptr of loaded message */ | |
62 | int state; /* one of STATE_* values */ | |
63 | }; | |
64 | ||
65 | struct mqueue_inode_info { | |
66 | spinlock_t lock; | |
67 | struct inode vfs_inode; | |
68 | wait_queue_head_t wait_q; | |
69 | ||
70 | struct rb_root msg_tree; | |
71 | struct posix_msg_tree_node *node_cache; | |
72 | struct mq_attr attr; | |
73 | ||
74 | struct sigevent notify; | |
75 | struct pid *notify_owner; | |
76 | struct user_namespace *notify_user_ns; | |
77 | struct user_struct *user; /* user who created, for accounting */ | |
78 | struct sock *notify_sock; | |
79 | struct sk_buff *notify_cookie; | |
80 | ||
81 | /* for tasks waiting for free space and messages, respectively */ | |
82 | struct ext_wait_queue e_wait_q[2]; | |
83 | ||
84 | unsigned long qsize; /* size of queue in memory (sum of all msgs) */ | |
85 | }; | |
86 | ||
87 | static const struct inode_operations mqueue_dir_inode_operations; | |
88 | static const struct file_operations mqueue_file_operations; | |
89 | static const struct super_operations mqueue_super_ops; | |
90 | static void remove_notification(struct mqueue_inode_info *info); | |
91 | ||
92 | static struct kmem_cache *mqueue_inode_cachep; | |
93 | ||
94 | static struct ctl_table_header *mq_sysctl_table; | |
95 | ||
96 | static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode) | |
97 | { | |
98 | return container_of(inode, struct mqueue_inode_info, vfs_inode); | |
99 | } | |
100 | ||
101 | /* | |
102 | * This routine should be called with the mq_lock held. | |
103 | */ | |
104 | static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode) | |
105 | { | |
106 | return get_ipc_ns(inode->i_sb->s_fs_info); | |
107 | } | |
108 | ||
109 | static struct ipc_namespace *get_ns_from_inode(struct inode *inode) | |
110 | { | |
111 | struct ipc_namespace *ns; | |
112 | ||
113 | spin_lock(&mq_lock); | |
114 | ns = __get_ns_from_inode(inode); | |
115 | spin_unlock(&mq_lock); | |
116 | return ns; | |
117 | } | |
118 | ||
119 | /* Auxiliary functions to manipulate messages' list */ | |
120 | static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info) | |
121 | { | |
122 | struct rb_node **p, *parent = NULL; | |
123 | struct posix_msg_tree_node *leaf; | |
124 | ||
125 | p = &info->msg_tree.rb_node; | |
126 | while (*p) { | |
127 | parent = *p; | |
128 | leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); | |
129 | ||
130 | if (likely(leaf->priority == msg->m_type)) | |
131 | goto insert_msg; | |
132 | else if (msg->m_type < leaf->priority) | |
133 | p = &(*p)->rb_left; | |
134 | else | |
135 | p = &(*p)->rb_right; | |
136 | } | |
137 | if (info->node_cache) { | |
138 | leaf = info->node_cache; | |
139 | info->node_cache = NULL; | |
140 | } else { | |
141 | leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC); | |
142 | if (!leaf) | |
143 | return -ENOMEM; | |
144 | INIT_LIST_HEAD(&leaf->msg_list); | |
145 | } | |
146 | leaf->priority = msg->m_type; | |
147 | rb_link_node(&leaf->rb_node, parent, p); | |
148 | rb_insert_color(&leaf->rb_node, &info->msg_tree); | |
149 | insert_msg: | |
150 | info->attr.mq_curmsgs++; | |
151 | info->qsize += msg->m_ts; | |
152 | list_add_tail(&msg->m_list, &leaf->msg_list); | |
153 | return 0; | |
154 | } | |
155 | ||
156 | static inline struct msg_msg *msg_get(struct mqueue_inode_info *info) | |
157 | { | |
158 | struct rb_node **p, *parent = NULL; | |
159 | struct posix_msg_tree_node *leaf; | |
160 | struct msg_msg *msg; | |
161 | ||
162 | try_again: | |
163 | p = &info->msg_tree.rb_node; | |
164 | while (*p) { | |
165 | parent = *p; | |
166 | /* | |
167 | * During insert, low priorities go to the left and high to the | |
168 | * right. On receive, we want the highest priorities first, so | |
169 | * walk all the way to the right. | |
170 | */ | |
171 | p = &(*p)->rb_right; | |
172 | } | |
173 | if (!parent) { | |
174 | if (info->attr.mq_curmsgs) { | |
175 | pr_warn_once("Inconsistency in POSIX message queue, " | |
176 | "no tree element, but supposedly messages " | |
177 | "should exist!\n"); | |
178 | info->attr.mq_curmsgs = 0; | |
179 | } | |
180 | return NULL; | |
181 | } | |
182 | leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); | |
183 | if (unlikely(list_empty(&leaf->msg_list))) { | |
184 | pr_warn_once("Inconsistency in POSIX message queue, " | |
185 | "empty leaf node but we haven't implemented " | |
186 | "lazy leaf delete!\n"); | |
187 | rb_erase(&leaf->rb_node, &info->msg_tree); | |
188 | if (info->node_cache) { | |
189 | kfree(leaf); | |
190 | } else { | |
191 | info->node_cache = leaf; | |
192 | } | |
193 | goto try_again; | |
194 | } else { | |
195 | msg = list_first_entry(&leaf->msg_list, | |
196 | struct msg_msg, m_list); | |
197 | list_del(&msg->m_list); | |
198 | if (list_empty(&leaf->msg_list)) { | |
199 | rb_erase(&leaf->rb_node, &info->msg_tree); | |
200 | if (info->node_cache) { | |
201 | kfree(leaf); | |
202 | } else { | |
203 | info->node_cache = leaf; | |
204 | } | |
205 | } | |
206 | } | |
207 | info->attr.mq_curmsgs--; | |
208 | info->qsize -= msg->m_ts; | |
209 | return msg; | |
210 | } | |
211 | ||
212 | static struct inode *mqueue_get_inode(struct super_block *sb, | |
213 | struct ipc_namespace *ipc_ns, umode_t mode, | |
214 | struct mq_attr *attr) | |
215 | { | |
216 | struct user_struct *u = current_user(); | |
217 | struct inode *inode; | |
218 | int ret = -ENOMEM; | |
219 | ||
220 | inode = new_inode(sb); | |
221 | if (!inode) | |
222 | goto err; | |
223 | ||
224 | inode->i_ino = get_next_ino(); | |
225 | inode->i_mode = mode; | |
226 | inode->i_uid = current_fsuid(); | |
227 | inode->i_gid = current_fsgid(); | |
228 | inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME; | |
229 | ||
230 | if (S_ISREG(mode)) { | |
231 | struct mqueue_inode_info *info; | |
232 | unsigned long mq_bytes, mq_treesize; | |
233 | ||
234 | inode->i_fop = &mqueue_file_operations; | |
235 | inode->i_size = FILENT_SIZE; | |
236 | /* mqueue specific info */ | |
237 | info = MQUEUE_I(inode); | |
238 | spin_lock_init(&info->lock); | |
239 | init_waitqueue_head(&info->wait_q); | |
240 | INIT_LIST_HEAD(&info->e_wait_q[0].list); | |
241 | INIT_LIST_HEAD(&info->e_wait_q[1].list); | |
242 | info->notify_owner = NULL; | |
243 | info->notify_user_ns = NULL; | |
244 | info->qsize = 0; | |
245 | info->user = NULL; /* set when all is ok */ | |
246 | info->msg_tree = RB_ROOT; | |
247 | info->node_cache = NULL; | |
248 | memset(&info->attr, 0, sizeof(info->attr)); | |
249 | info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max, | |
250 | ipc_ns->mq_msg_default); | |
251 | info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, | |
252 | ipc_ns->mq_msgsize_default); | |
253 | if (attr) { | |
254 | info->attr.mq_maxmsg = attr->mq_maxmsg; | |
255 | info->attr.mq_msgsize = attr->mq_msgsize; | |
256 | } | |
257 | /* | |
258 | * We used to allocate a static array of pointers and account | |
259 | * the size of that array as well as one msg_msg struct per | |
260 | * possible message into the queue size. That's no longer | |
261 | * accurate as the queue is now an rbtree and will grow and | |
262 | * shrink depending on usage patterns. We can, however, still | |
263 | * account one msg_msg struct per message, but the nodes are | |
264 | * allocated depending on priority usage, and most programs | |
265 | * only use one, or a handful, of priorities. However, since | |
266 | * this is pinned memory, we need to assume worst case, so | |
267 | * that means the min(mq_maxmsg, max_priorities) * struct | |
268 | * posix_msg_tree_node. | |
269 | */ | |
270 | mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + | |
271 | min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * | |
272 | sizeof(struct posix_msg_tree_node); | |
273 | ||
274 | mq_bytes = mq_treesize + (info->attr.mq_maxmsg * | |
275 | info->attr.mq_msgsize); | |
276 | ||
277 | spin_lock(&mq_lock); | |
278 | if (u->mq_bytes + mq_bytes < u->mq_bytes || | |
279 | u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) { | |
280 | spin_unlock(&mq_lock); | |
281 | /* mqueue_evict_inode() releases info->messages */ | |
282 | ret = -EMFILE; | |
283 | goto out_inode; | |
284 | } | |
285 | u->mq_bytes += mq_bytes; | |
286 | spin_unlock(&mq_lock); | |
287 | ||
288 | /* all is ok */ | |
289 | info->user = get_uid(u); | |
290 | } else if (S_ISDIR(mode)) { | |
291 | inc_nlink(inode); | |
292 | /* Some things misbehave if size == 0 on a directory */ | |
293 | inode->i_size = 2 * DIRENT_SIZE; | |
294 | inode->i_op = &mqueue_dir_inode_operations; | |
295 | inode->i_fop = &simple_dir_operations; | |
296 | } | |
297 | ||
298 | return inode; | |
299 | out_inode: | |
300 | iput(inode); | |
301 | err: | |
302 | return ERR_PTR(ret); | |
303 | } | |
304 | ||
305 | static int mqueue_fill_super(struct super_block *sb, void *data, int silent) | |
306 | { | |
307 | struct inode *inode; | |
308 | struct ipc_namespace *ns = data; | |
309 | ||
310 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
311 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
312 | sb->s_magic = MQUEUE_MAGIC; | |
313 | sb->s_op = &mqueue_super_ops; | |
314 | ||
315 | inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL); | |
316 | if (IS_ERR(inode)) | |
317 | return PTR_ERR(inode); | |
318 | ||
319 | sb->s_root = d_make_root(inode); | |
320 | if (!sb->s_root) | |
321 | return -ENOMEM; | |
322 | return 0; | |
323 | } | |
324 | ||
325 | static struct dentry *mqueue_mount(struct file_system_type *fs_type, | |
326 | int flags, const char *dev_name, | |
327 | void *data) | |
328 | { | |
329 | if (!(flags & MS_KERNMOUNT)) { | |
330 | struct ipc_namespace *ns = current->nsproxy->ipc_ns; | |
331 | /* Don't allow mounting unless the caller has CAP_SYS_ADMIN | |
332 | * over the ipc namespace. | |
333 | */ | |
334 | if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) | |
335 | return ERR_PTR(-EPERM); | |
336 | ||
337 | data = ns; | |
338 | } | |
339 | return mount_ns(fs_type, flags, data, mqueue_fill_super); | |
340 | } | |
341 | ||
342 | static void init_once(void *foo) | |
343 | { | |
344 | struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo; | |
345 | ||
346 | inode_init_once(&p->vfs_inode); | |
347 | } | |
348 | ||
349 | static struct inode *mqueue_alloc_inode(struct super_block *sb) | |
350 | { | |
351 | struct mqueue_inode_info *ei; | |
352 | ||
353 | ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL); | |
354 | if (!ei) | |
355 | return NULL; | |
356 | return &ei->vfs_inode; | |
357 | } | |
358 | ||
359 | static void mqueue_i_callback(struct rcu_head *head) | |
360 | { | |
361 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
362 | kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode)); | |
363 | } | |
364 | ||
365 | static void mqueue_destroy_inode(struct inode *inode) | |
366 | { | |
367 | call_rcu(&inode->i_rcu, mqueue_i_callback); | |
368 | } | |
369 | ||
370 | static void mqueue_evict_inode(struct inode *inode) | |
371 | { | |
372 | struct mqueue_inode_info *info; | |
373 | struct user_struct *user; | |
374 | unsigned long mq_bytes, mq_treesize; | |
375 | struct ipc_namespace *ipc_ns; | |
376 | struct msg_msg *msg; | |
377 | ||
378 | clear_inode(inode); | |
379 | ||
380 | if (S_ISDIR(inode->i_mode)) | |
381 | return; | |
382 | ||
383 | ipc_ns = get_ns_from_inode(inode); | |
384 | info = MQUEUE_I(inode); | |
385 | spin_lock(&info->lock); | |
386 | while ((msg = msg_get(info)) != NULL) | |
387 | free_msg(msg); | |
388 | kfree(info->node_cache); | |
389 | spin_unlock(&info->lock); | |
390 | ||
391 | /* Total amount of bytes accounted for the mqueue */ | |
392 | mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + | |
393 | min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * | |
394 | sizeof(struct posix_msg_tree_node); | |
395 | ||
396 | mq_bytes = mq_treesize + (info->attr.mq_maxmsg * | |
397 | info->attr.mq_msgsize); | |
398 | ||
399 | user = info->user; | |
400 | if (user) { | |
401 | spin_lock(&mq_lock); | |
402 | user->mq_bytes -= mq_bytes; | |
403 | /* | |
404 | * get_ns_from_inode() ensures that the | |
405 | * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns | |
406 | * to which we now hold a reference, or it is NULL. | |
407 | * We can't put it here under mq_lock, though. | |
408 | */ | |
409 | if (ipc_ns) | |
410 | ipc_ns->mq_queues_count--; | |
411 | spin_unlock(&mq_lock); | |
412 | free_uid(user); | |
413 | } | |
414 | if (ipc_ns) | |
415 | put_ipc_ns(ipc_ns); | |
416 | } | |
417 | ||
418 | static int mqueue_create(struct inode *dir, struct dentry *dentry, | |
419 | umode_t mode, bool excl) | |
420 | { | |
421 | struct inode *inode; | |
422 | struct mq_attr *attr = dentry->d_fsdata; | |
423 | int error; | |
424 | struct ipc_namespace *ipc_ns; | |
425 | ||
426 | spin_lock(&mq_lock); | |
427 | ipc_ns = __get_ns_from_inode(dir); | |
428 | if (!ipc_ns) { | |
429 | error = -EACCES; | |
430 | goto out_unlock; | |
431 | } | |
432 | ||
433 | if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max && | |
434 | !capable(CAP_SYS_RESOURCE)) { | |
435 | error = -ENOSPC; | |
436 | goto out_unlock; | |
437 | } | |
438 | ipc_ns->mq_queues_count++; | |
439 | spin_unlock(&mq_lock); | |
440 | ||
441 | inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr); | |
442 | if (IS_ERR(inode)) { | |
443 | error = PTR_ERR(inode); | |
444 | spin_lock(&mq_lock); | |
445 | ipc_ns->mq_queues_count--; | |
446 | goto out_unlock; | |
447 | } | |
448 | ||
449 | put_ipc_ns(ipc_ns); | |
450 | dir->i_size += DIRENT_SIZE; | |
451 | dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; | |
452 | ||
453 | d_instantiate(dentry, inode); | |
454 | dget(dentry); | |
455 | return 0; | |
456 | out_unlock: | |
457 | spin_unlock(&mq_lock); | |
458 | if (ipc_ns) | |
459 | put_ipc_ns(ipc_ns); | |
460 | return error; | |
461 | } | |
462 | ||
463 | static int mqueue_unlink(struct inode *dir, struct dentry *dentry) | |
464 | { | |
465 | struct inode *inode = d_inode(dentry); | |
466 | ||
467 | dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; | |
468 | dir->i_size -= DIRENT_SIZE; | |
469 | drop_nlink(inode); | |
470 | dput(dentry); | |
471 | return 0; | |
472 | } | |
473 | ||
474 | /* | |
475 | * This is routine for system read from queue file. | |
476 | * To avoid mess with doing here some sort of mq_receive we allow | |
477 | * to read only queue size & notification info (the only values | |
478 | * that are interesting from user point of view and aren't accessible | |
479 | * through std routines) | |
480 | */ | |
481 | static ssize_t mqueue_read_file(struct file *filp, char __user *u_data, | |
482 | size_t count, loff_t *off) | |
483 | { | |
484 | struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); | |
485 | char buffer[FILENT_SIZE]; | |
486 | ssize_t ret; | |
487 | ||
488 | spin_lock(&info->lock); | |
489 | snprintf(buffer, sizeof(buffer), | |
490 | "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n", | |
491 | info->qsize, | |
492 | info->notify_owner ? info->notify.sigev_notify : 0, | |
493 | (info->notify_owner && | |
494 | info->notify.sigev_notify == SIGEV_SIGNAL) ? | |
495 | info->notify.sigev_signo : 0, | |
496 | pid_vnr(info->notify_owner)); | |
497 | spin_unlock(&info->lock); | |
498 | buffer[sizeof(buffer)-1] = '\0'; | |
499 | ||
500 | ret = simple_read_from_buffer(u_data, count, off, buffer, | |
501 | strlen(buffer)); | |
502 | if (ret <= 0) | |
503 | return ret; | |
504 | ||
505 | file_inode(filp)->i_atime = file_inode(filp)->i_ctime = CURRENT_TIME; | |
506 | return ret; | |
507 | } | |
508 | ||
509 | static int mqueue_flush_file(struct file *filp, fl_owner_t id) | |
510 | { | |
511 | struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); | |
512 | ||
513 | spin_lock(&info->lock); | |
514 | if (task_tgid(current) == info->notify_owner) | |
515 | remove_notification(info); | |
516 | ||
517 | spin_unlock(&info->lock); | |
518 | return 0; | |
519 | } | |
520 | ||
521 | static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab) | |
522 | { | |
523 | struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); | |
524 | int retval = 0; | |
525 | ||
526 | poll_wait(filp, &info->wait_q, poll_tab); | |
527 | ||
528 | spin_lock(&info->lock); | |
529 | if (info->attr.mq_curmsgs) | |
530 | retval = POLLIN | POLLRDNORM; | |
531 | ||
532 | if (info->attr.mq_curmsgs < info->attr.mq_maxmsg) | |
533 | retval |= POLLOUT | POLLWRNORM; | |
534 | spin_unlock(&info->lock); | |
535 | ||
536 | return retval; | |
537 | } | |
538 | ||
539 | /* Adds current to info->e_wait_q[sr] before element with smaller prio */ | |
540 | static void wq_add(struct mqueue_inode_info *info, int sr, | |
541 | struct ext_wait_queue *ewp) | |
542 | { | |
543 | struct ext_wait_queue *walk; | |
544 | ||
545 | ewp->task = current; | |
546 | ||
547 | list_for_each_entry(walk, &info->e_wait_q[sr].list, list) { | |
548 | if (walk->task->static_prio <= current->static_prio) { | |
549 | list_add_tail(&ewp->list, &walk->list); | |
550 | return; | |
551 | } | |
552 | } | |
553 | list_add_tail(&ewp->list, &info->e_wait_q[sr].list); | |
554 | } | |
555 | ||
556 | /* | |
557 | * Puts current task to sleep. Caller must hold queue lock. After return | |
558 | * lock isn't held. | |
559 | * sr: SEND or RECV | |
560 | */ | |
561 | static int wq_sleep(struct mqueue_inode_info *info, int sr, | |
562 | ktime_t *timeout, struct ext_wait_queue *ewp) | |
563 | { | |
564 | int retval; | |
565 | signed long time; | |
566 | ||
567 | wq_add(info, sr, ewp); | |
568 | ||
569 | for (;;) { | |
570 | __set_current_state(TASK_INTERRUPTIBLE); | |
571 | ||
572 | spin_unlock(&info->lock); | |
573 | time = schedule_hrtimeout_range_clock(timeout, 0, | |
574 | HRTIMER_MODE_ABS, CLOCK_REALTIME); | |
575 | ||
576 | if (ewp->state == STATE_READY) { | |
577 | retval = 0; | |
578 | goto out; | |
579 | } | |
580 | spin_lock(&info->lock); | |
581 | if (ewp->state == STATE_READY) { | |
582 | retval = 0; | |
583 | goto out_unlock; | |
584 | } | |
585 | if (signal_pending(current)) { | |
586 | retval = -ERESTARTSYS; | |
587 | break; | |
588 | } | |
589 | if (time == 0) { | |
590 | retval = -ETIMEDOUT; | |
591 | break; | |
592 | } | |
593 | } | |
594 | list_del(&ewp->list); | |
595 | out_unlock: | |
596 | spin_unlock(&info->lock); | |
597 | out: | |
598 | return retval; | |
599 | } | |
600 | ||
601 | /* | |
602 | * Returns waiting task that should be serviced first or NULL if none exists | |
603 | */ | |
604 | static struct ext_wait_queue *wq_get_first_waiter( | |
605 | struct mqueue_inode_info *info, int sr) | |
606 | { | |
607 | struct list_head *ptr; | |
608 | ||
609 | ptr = info->e_wait_q[sr].list.prev; | |
610 | if (ptr == &info->e_wait_q[sr].list) | |
611 | return NULL; | |
612 | return list_entry(ptr, struct ext_wait_queue, list); | |
613 | } | |
614 | ||
615 | ||
616 | static inline void set_cookie(struct sk_buff *skb, char code) | |
617 | { | |
618 | ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code; | |
619 | } | |
620 | ||
621 | /* | |
622 | * The next function is only to split too long sys_mq_timedsend | |
623 | */ | |
624 | static void __do_notify(struct mqueue_inode_info *info) | |
625 | { | |
626 | /* notification | |
627 | * invoked when there is registered process and there isn't process | |
628 | * waiting synchronously for message AND state of queue changed from | |
629 | * empty to not empty. Here we are sure that no one is waiting | |
630 | * synchronously. */ | |
631 | if (info->notify_owner && | |
632 | info->attr.mq_curmsgs == 1) { | |
633 | struct siginfo sig_i; | |
634 | switch (info->notify.sigev_notify) { | |
635 | case SIGEV_NONE: | |
636 | break; | |
637 | case SIGEV_SIGNAL: | |
638 | /* sends signal */ | |
639 | ||
640 | sig_i.si_signo = info->notify.sigev_signo; | |
641 | sig_i.si_errno = 0; | |
642 | sig_i.si_code = SI_MESGQ; | |
643 | sig_i.si_value = info->notify.sigev_value; | |
644 | /* map current pid/uid into info->owner's namespaces */ | |
645 | rcu_read_lock(); | |
646 | sig_i.si_pid = task_tgid_nr_ns(current, | |
647 | ns_of_pid(info->notify_owner)); | |
648 | sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid()); | |
649 | rcu_read_unlock(); | |
650 | ||
651 | kill_pid_info(info->notify.sigev_signo, | |
652 | &sig_i, info->notify_owner); | |
653 | break; | |
654 | case SIGEV_THREAD: | |
655 | set_cookie(info->notify_cookie, NOTIFY_WOKENUP); | |
656 | netlink_sendskb(info->notify_sock, info->notify_cookie); | |
657 | break; | |
658 | } | |
659 | /* after notification unregisters process */ | |
660 | put_pid(info->notify_owner); | |
661 | put_user_ns(info->notify_user_ns); | |
662 | info->notify_owner = NULL; | |
663 | info->notify_user_ns = NULL; | |
664 | } | |
665 | wake_up(&info->wait_q); | |
666 | } | |
667 | ||
668 | static int prepare_timeout(const struct timespec __user *u_abs_timeout, | |
669 | ktime_t *expires, struct timespec *ts) | |
670 | { | |
671 | if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec))) | |
672 | return -EFAULT; | |
673 | if (!timespec_valid(ts)) | |
674 | return -EINVAL; | |
675 | ||
676 | *expires = timespec_to_ktime(*ts); | |
677 | return 0; | |
678 | } | |
679 | ||
680 | static void remove_notification(struct mqueue_inode_info *info) | |
681 | { | |
682 | if (info->notify_owner != NULL && | |
683 | info->notify.sigev_notify == SIGEV_THREAD) { | |
684 | set_cookie(info->notify_cookie, NOTIFY_REMOVED); | |
685 | netlink_sendskb(info->notify_sock, info->notify_cookie); | |
686 | } | |
687 | put_pid(info->notify_owner); | |
688 | put_user_ns(info->notify_user_ns); | |
689 | info->notify_owner = NULL; | |
690 | info->notify_user_ns = NULL; | |
691 | } | |
692 | ||
693 | static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr) | |
694 | { | |
695 | int mq_treesize; | |
696 | unsigned long total_size; | |
697 | ||
698 | if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0) | |
699 | return -EINVAL; | |
700 | if (capable(CAP_SYS_RESOURCE)) { | |
701 | if (attr->mq_maxmsg > HARD_MSGMAX || | |
702 | attr->mq_msgsize > HARD_MSGSIZEMAX) | |
703 | return -EINVAL; | |
704 | } else { | |
705 | if (attr->mq_maxmsg > ipc_ns->mq_msg_max || | |
706 | attr->mq_msgsize > ipc_ns->mq_msgsize_max) | |
707 | return -EINVAL; | |
708 | } | |
709 | /* check for overflow */ | |
710 | if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg) | |
711 | return -EOVERFLOW; | |
712 | mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) + | |
713 | min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) * | |
714 | sizeof(struct posix_msg_tree_node); | |
715 | total_size = attr->mq_maxmsg * attr->mq_msgsize; | |
716 | if (total_size + mq_treesize < total_size) | |
717 | return -EOVERFLOW; | |
718 | return 0; | |
719 | } | |
720 | ||
721 | /* | |
722 | * Invoked when creating a new queue via sys_mq_open | |
723 | */ | |
724 | static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir, | |
725 | struct path *path, int oflag, umode_t mode, | |
726 | struct mq_attr *attr) | |
727 | { | |
728 | const struct cred *cred = current_cred(); | |
729 | int ret; | |
730 | ||
731 | if (attr) { | |
732 | ret = mq_attr_ok(ipc_ns, attr); | |
733 | if (ret) | |
734 | return ERR_PTR(ret); | |
735 | /* store for use during create */ | |
736 | path->dentry->d_fsdata = attr; | |
737 | } else { | |
738 | struct mq_attr def_attr; | |
739 | ||
740 | def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max, | |
741 | ipc_ns->mq_msg_default); | |
742 | def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, | |
743 | ipc_ns->mq_msgsize_default); | |
744 | ret = mq_attr_ok(ipc_ns, &def_attr); | |
745 | if (ret) | |
746 | return ERR_PTR(ret); | |
747 | } | |
748 | ||
749 | mode &= ~current_umask(); | |
750 | ret = vfs_create(dir, path->dentry, mode, true); | |
751 | path->dentry->d_fsdata = NULL; | |
752 | if (ret) | |
753 | return ERR_PTR(ret); | |
754 | return dentry_open(path, oflag, cred); | |
755 | } | |
756 | ||
757 | /* Opens existing queue */ | |
758 | static struct file *do_open(struct path *path, int oflag) | |
759 | { | |
760 | static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE, | |
761 | MAY_READ | MAY_WRITE }; | |
762 | int acc; | |
763 | if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) | |
764 | return ERR_PTR(-EINVAL); | |
765 | acc = oflag2acc[oflag & O_ACCMODE]; | |
766 | if (inode_permission(d_inode(path->dentry), acc)) | |
767 | return ERR_PTR(-EACCES); | |
768 | return dentry_open(path, oflag, current_cred()); | |
769 | } | |
770 | ||
771 | SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode, | |
772 | struct mq_attr __user *, u_attr) | |
773 | { | |
774 | struct path path; | |
775 | struct file *filp; | |
776 | struct filename *name; | |
777 | struct mq_attr attr; | |
778 | int fd, error; | |
779 | struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; | |
780 | struct vfsmount *mnt = ipc_ns->mq_mnt; | |
781 | struct dentry *root = mnt->mnt_root; | |
782 | int ro; | |
783 | ||
784 | if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr))) | |
785 | return -EFAULT; | |
786 | ||
787 | audit_mq_open(oflag, mode, u_attr ? &attr : NULL); | |
788 | ||
789 | if (IS_ERR(name = getname(u_name))) | |
790 | return PTR_ERR(name); | |
791 | ||
792 | fd = get_unused_fd_flags(O_CLOEXEC); | |
793 | if (fd < 0) | |
794 | goto out_putname; | |
795 | ||
796 | ro = mnt_want_write(mnt); /* we'll drop it in any case */ | |
797 | error = 0; | |
798 | mutex_lock(&d_inode(root)->i_mutex); | |
799 | path.dentry = lookup_one_len(name->name, root, strlen(name->name)); | |
800 | if (IS_ERR(path.dentry)) { | |
801 | error = PTR_ERR(path.dentry); | |
802 | goto out_putfd; | |
803 | } | |
804 | path.mnt = mntget(mnt); | |
805 | ||
806 | if (oflag & O_CREAT) { | |
807 | if (d_really_is_positive(path.dentry)) { /* entry already exists */ | |
808 | audit_inode(name, path.dentry, 0); | |
809 | if (oflag & O_EXCL) { | |
810 | error = -EEXIST; | |
811 | goto out; | |
812 | } | |
813 | filp = do_open(&path, oflag); | |
814 | } else { | |
815 | if (ro) { | |
816 | error = ro; | |
817 | goto out; | |
818 | } | |
819 | audit_inode_parent_hidden(name, root); | |
820 | filp = do_create(ipc_ns, d_inode(root), | |
821 | &path, oflag, mode, | |
822 | u_attr ? &attr : NULL); | |
823 | } | |
824 | } else { | |
825 | if (d_really_is_negative(path.dentry)) { | |
826 | error = -ENOENT; | |
827 | goto out; | |
828 | } | |
829 | audit_inode(name, path.dentry, 0); | |
830 | filp = do_open(&path, oflag); | |
831 | } | |
832 | ||
833 | if (!IS_ERR(filp)) | |
834 | fd_install(fd, filp); | |
835 | else | |
836 | error = PTR_ERR(filp); | |
837 | out: | |
838 | path_put(&path); | |
839 | out_putfd: | |
840 | if (error) { | |
841 | put_unused_fd(fd); | |
842 | fd = error; | |
843 | } | |
844 | mutex_unlock(&d_inode(root)->i_mutex); | |
845 | if (!ro) | |
846 | mnt_drop_write(mnt); | |
847 | out_putname: | |
848 | putname(name); | |
849 | return fd; | |
850 | } | |
851 | ||
852 | SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name) | |
853 | { | |
854 | int err; | |
855 | struct filename *name; | |
856 | struct dentry *dentry; | |
857 | struct inode *inode = NULL; | |
858 | struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; | |
859 | struct vfsmount *mnt = ipc_ns->mq_mnt; | |
860 | ||
861 | name = getname(u_name); | |
862 | if (IS_ERR(name)) | |
863 | return PTR_ERR(name); | |
864 | ||
865 | audit_inode_parent_hidden(name, mnt->mnt_root); | |
866 | err = mnt_want_write(mnt); | |
867 | if (err) | |
868 | goto out_name; | |
869 | mutex_lock_nested(&d_inode(mnt->mnt_root)->i_mutex, I_MUTEX_PARENT); | |
870 | dentry = lookup_one_len(name->name, mnt->mnt_root, | |
871 | strlen(name->name)); | |
872 | if (IS_ERR(dentry)) { | |
873 | err = PTR_ERR(dentry); | |
874 | goto out_unlock; | |
875 | } | |
876 | ||
877 | inode = d_inode(dentry); | |
878 | if (!inode) { | |
879 | err = -ENOENT; | |
880 | } else { | |
881 | ihold(inode); | |
882 | err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL); | |
883 | } | |
884 | dput(dentry); | |
885 | ||
886 | out_unlock: | |
887 | mutex_unlock(&d_inode(mnt->mnt_root)->i_mutex); | |
888 | if (inode) | |
889 | iput(inode); | |
890 | mnt_drop_write(mnt); | |
891 | out_name: | |
892 | putname(name); | |
893 | ||
894 | return err; | |
895 | } | |
896 | ||
897 | /* Pipelined send and receive functions. | |
898 | * | |
899 | * If a receiver finds no waiting message, then it registers itself in the | |
900 | * list of waiting receivers. A sender checks that list before adding the new | |
901 | * message into the message array. If there is a waiting receiver, then it | |
902 | * bypasses the message array and directly hands the message over to the | |
903 | * receiver. The receiver accepts the message and returns without grabbing the | |
904 | * queue spinlock: | |
905 | * | |
906 | * - Set pointer to message. | |
907 | * - Queue the receiver task for later wakeup (without the info->lock). | |
908 | * - Update its state to STATE_READY. Now the receiver can continue. | |
909 | * - Wake up the process after the lock is dropped. Should the process wake up | |
910 | * before this wakeup (due to a timeout or a signal) it will either see | |
911 | * STATE_READY and continue or acquire the lock to check the state again. | |
912 | * | |
913 | * The same algorithm is used for senders. | |
914 | */ | |
915 | ||
916 | /* pipelined_send() - send a message directly to the task waiting in | |
917 | * sys_mq_timedreceive() (without inserting message into a queue). | |
918 | */ | |
919 | static inline void pipelined_send(struct wake_q_head *wake_q, | |
920 | struct mqueue_inode_info *info, | |
921 | struct msg_msg *message, | |
922 | struct ext_wait_queue *receiver) | |
923 | { | |
924 | receiver->msg = message; | |
925 | list_del(&receiver->list); | |
926 | wake_q_add(wake_q, receiver->task); | |
927 | /* | |
928 | * Rely on the implicit cmpxchg barrier from wake_q_add such | |
929 | * that we can ensure that updating receiver->state is the last | |
930 | * write operation: As once set, the receiver can continue, | |
931 | * and if we don't have the reference count from the wake_q, | |
932 | * yet, at that point we can later have a use-after-free | |
933 | * condition and bogus wakeup. | |
934 | */ | |
935 | receiver->state = STATE_READY; | |
936 | } | |
937 | ||
938 | /* pipelined_receive() - if there is task waiting in sys_mq_timedsend() | |
939 | * gets its message and put to the queue (we have one free place for sure). */ | |
940 | static inline void pipelined_receive(struct wake_q_head *wake_q, | |
941 | struct mqueue_inode_info *info) | |
942 | { | |
943 | struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND); | |
944 | ||
945 | if (!sender) { | |
946 | /* for poll */ | |
947 | wake_up_interruptible(&info->wait_q); | |
948 | return; | |
949 | } | |
950 | if (msg_insert(sender->msg, info)) | |
951 | return; | |
952 | ||
953 | list_del(&sender->list); | |
954 | wake_q_add(wake_q, sender->task); | |
955 | sender->state = STATE_READY; | |
956 | } | |
957 | ||
958 | SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr, | |
959 | size_t, msg_len, unsigned int, msg_prio, | |
960 | const struct timespec __user *, u_abs_timeout) | |
961 | { | |
962 | struct fd f; | |
963 | struct inode *inode; | |
964 | struct ext_wait_queue wait; | |
965 | struct ext_wait_queue *receiver; | |
966 | struct msg_msg *msg_ptr; | |
967 | struct mqueue_inode_info *info; | |
968 | ktime_t expires, *timeout = NULL; | |
969 | struct timespec ts; | |
970 | struct posix_msg_tree_node *new_leaf = NULL; | |
971 | int ret = 0; | |
972 | WAKE_Q(wake_q); | |
973 | ||
974 | if (u_abs_timeout) { | |
975 | int res = prepare_timeout(u_abs_timeout, &expires, &ts); | |
976 | if (res) | |
977 | return res; | |
978 | timeout = &expires; | |
979 | } | |
980 | ||
981 | if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX)) | |
982 | return -EINVAL; | |
983 | ||
984 | audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL); | |
985 | ||
986 | f = fdget(mqdes); | |
987 | if (unlikely(!f.file)) { | |
988 | ret = -EBADF; | |
989 | goto out; | |
990 | } | |
991 | ||
992 | inode = file_inode(f.file); | |
993 | if (unlikely(f.file->f_op != &mqueue_file_operations)) { | |
994 | ret = -EBADF; | |
995 | goto out_fput; | |
996 | } | |
997 | info = MQUEUE_I(inode); | |
998 | audit_file(f.file); | |
999 | ||
1000 | if (unlikely(!(f.file->f_mode & FMODE_WRITE))) { | |
1001 | ret = -EBADF; | |
1002 | goto out_fput; | |
1003 | } | |
1004 | ||
1005 | if (unlikely(msg_len > info->attr.mq_msgsize)) { | |
1006 | ret = -EMSGSIZE; | |
1007 | goto out_fput; | |
1008 | } | |
1009 | ||
1010 | /* First try to allocate memory, before doing anything with | |
1011 | * existing queues. */ | |
1012 | msg_ptr = load_msg(u_msg_ptr, msg_len); | |
1013 | if (IS_ERR(msg_ptr)) { | |
1014 | ret = PTR_ERR(msg_ptr); | |
1015 | goto out_fput; | |
1016 | } | |
1017 | msg_ptr->m_ts = msg_len; | |
1018 | msg_ptr->m_type = msg_prio; | |
1019 | ||
1020 | /* | |
1021 | * msg_insert really wants us to have a valid, spare node struct so | |
1022 | * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will | |
1023 | * fall back to that if necessary. | |
1024 | */ | |
1025 | if (!info->node_cache) | |
1026 | new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); | |
1027 | ||
1028 | spin_lock(&info->lock); | |
1029 | ||
1030 | if (!info->node_cache && new_leaf) { | |
1031 | /* Save our speculative allocation into the cache */ | |
1032 | INIT_LIST_HEAD(&new_leaf->msg_list); | |
1033 | info->node_cache = new_leaf; | |
1034 | new_leaf = NULL; | |
1035 | } else { | |
1036 | kfree(new_leaf); | |
1037 | } | |
1038 | ||
1039 | if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) { | |
1040 | if (f.file->f_flags & O_NONBLOCK) { | |
1041 | ret = -EAGAIN; | |
1042 | } else { | |
1043 | wait.task = current; | |
1044 | wait.msg = (void *) msg_ptr; | |
1045 | wait.state = STATE_NONE; | |
1046 | ret = wq_sleep(info, SEND, timeout, &wait); | |
1047 | /* | |
1048 | * wq_sleep must be called with info->lock held, and | |
1049 | * returns with the lock released | |
1050 | */ | |
1051 | goto out_free; | |
1052 | } | |
1053 | } else { | |
1054 | receiver = wq_get_first_waiter(info, RECV); | |
1055 | if (receiver) { | |
1056 | pipelined_send(&wake_q, info, msg_ptr, receiver); | |
1057 | } else { | |
1058 | /* adds message to the queue */ | |
1059 | ret = msg_insert(msg_ptr, info); | |
1060 | if (ret) | |
1061 | goto out_unlock; | |
1062 | __do_notify(info); | |
1063 | } | |
1064 | inode->i_atime = inode->i_mtime = inode->i_ctime = | |
1065 | CURRENT_TIME; | |
1066 | } | |
1067 | out_unlock: | |
1068 | spin_unlock(&info->lock); | |
1069 | wake_up_q(&wake_q); | |
1070 | out_free: | |
1071 | if (ret) | |
1072 | free_msg(msg_ptr); | |
1073 | out_fput: | |
1074 | fdput(f); | |
1075 | out: | |
1076 | return ret; | |
1077 | } | |
1078 | ||
1079 | SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr, | |
1080 | size_t, msg_len, unsigned int __user *, u_msg_prio, | |
1081 | const struct timespec __user *, u_abs_timeout) | |
1082 | { | |
1083 | ssize_t ret; | |
1084 | struct msg_msg *msg_ptr; | |
1085 | struct fd f; | |
1086 | struct inode *inode; | |
1087 | struct mqueue_inode_info *info; | |
1088 | struct ext_wait_queue wait; | |
1089 | ktime_t expires, *timeout = NULL; | |
1090 | struct timespec ts; | |
1091 | struct posix_msg_tree_node *new_leaf = NULL; | |
1092 | ||
1093 | if (u_abs_timeout) { | |
1094 | int res = prepare_timeout(u_abs_timeout, &expires, &ts); | |
1095 | if (res) | |
1096 | return res; | |
1097 | timeout = &expires; | |
1098 | } | |
1099 | ||
1100 | audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL); | |
1101 | ||
1102 | f = fdget(mqdes); | |
1103 | if (unlikely(!f.file)) { | |
1104 | ret = -EBADF; | |
1105 | goto out; | |
1106 | } | |
1107 | ||
1108 | inode = file_inode(f.file); | |
1109 | if (unlikely(f.file->f_op != &mqueue_file_operations)) { | |
1110 | ret = -EBADF; | |
1111 | goto out_fput; | |
1112 | } | |
1113 | info = MQUEUE_I(inode); | |
1114 | audit_file(f.file); | |
1115 | ||
1116 | if (unlikely(!(f.file->f_mode & FMODE_READ))) { | |
1117 | ret = -EBADF; | |
1118 | goto out_fput; | |
1119 | } | |
1120 | ||
1121 | /* checks if buffer is big enough */ | |
1122 | if (unlikely(msg_len < info->attr.mq_msgsize)) { | |
1123 | ret = -EMSGSIZE; | |
1124 | goto out_fput; | |
1125 | } | |
1126 | ||
1127 | /* | |
1128 | * msg_insert really wants us to have a valid, spare node struct so | |
1129 | * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will | |
1130 | * fall back to that if necessary. | |
1131 | */ | |
1132 | if (!info->node_cache) | |
1133 | new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); | |
1134 | ||
1135 | spin_lock(&info->lock); | |
1136 | ||
1137 | if (!info->node_cache && new_leaf) { | |
1138 | /* Save our speculative allocation into the cache */ | |
1139 | INIT_LIST_HEAD(&new_leaf->msg_list); | |
1140 | info->node_cache = new_leaf; | |
1141 | } else { | |
1142 | kfree(new_leaf); | |
1143 | } | |
1144 | ||
1145 | if (info->attr.mq_curmsgs == 0) { | |
1146 | if (f.file->f_flags & O_NONBLOCK) { | |
1147 | spin_unlock(&info->lock); | |
1148 | ret = -EAGAIN; | |
1149 | } else { | |
1150 | wait.task = current; | |
1151 | wait.state = STATE_NONE; | |
1152 | ret = wq_sleep(info, RECV, timeout, &wait); | |
1153 | msg_ptr = wait.msg; | |
1154 | } | |
1155 | } else { | |
1156 | WAKE_Q(wake_q); | |
1157 | ||
1158 | msg_ptr = msg_get(info); | |
1159 | ||
1160 | inode->i_atime = inode->i_mtime = inode->i_ctime = | |
1161 | CURRENT_TIME; | |
1162 | ||
1163 | /* There is now free space in queue. */ | |
1164 | pipelined_receive(&wake_q, info); | |
1165 | spin_unlock(&info->lock); | |
1166 | wake_up_q(&wake_q); | |
1167 | ret = 0; | |
1168 | } | |
1169 | if (ret == 0) { | |
1170 | ret = msg_ptr->m_ts; | |
1171 | ||
1172 | if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) || | |
1173 | store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) { | |
1174 | ret = -EFAULT; | |
1175 | } | |
1176 | free_msg(msg_ptr); | |
1177 | } | |
1178 | out_fput: | |
1179 | fdput(f); | |
1180 | out: | |
1181 | return ret; | |
1182 | } | |
1183 | ||
1184 | /* | |
1185 | * Notes: the case when user wants us to deregister (with NULL as pointer) | |
1186 | * and he isn't currently owner of notification, will be silently discarded. | |
1187 | * It isn't explicitly defined in the POSIX. | |
1188 | */ | |
1189 | SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes, | |
1190 | const struct sigevent __user *, u_notification) | |
1191 | { | |
1192 | int ret; | |
1193 | struct fd f; | |
1194 | struct sock *sock; | |
1195 | struct inode *inode; | |
1196 | struct sigevent notification; | |
1197 | struct mqueue_inode_info *info; | |
1198 | struct sk_buff *nc; | |
1199 | ||
1200 | if (u_notification) { | |
1201 | if (copy_from_user(¬ification, u_notification, | |
1202 | sizeof(struct sigevent))) | |
1203 | return -EFAULT; | |
1204 | } | |
1205 | ||
1206 | audit_mq_notify(mqdes, u_notification ? ¬ification : NULL); | |
1207 | ||
1208 | nc = NULL; | |
1209 | sock = NULL; | |
1210 | if (u_notification != NULL) { | |
1211 | if (unlikely(notification.sigev_notify != SIGEV_NONE && | |
1212 | notification.sigev_notify != SIGEV_SIGNAL && | |
1213 | notification.sigev_notify != SIGEV_THREAD)) | |
1214 | return -EINVAL; | |
1215 | if (notification.sigev_notify == SIGEV_SIGNAL && | |
1216 | !valid_signal(notification.sigev_signo)) { | |
1217 | return -EINVAL; | |
1218 | } | |
1219 | if (notification.sigev_notify == SIGEV_THREAD) { | |
1220 | long timeo; | |
1221 | ||
1222 | /* create the notify skb */ | |
1223 | nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL); | |
1224 | if (!nc) { | |
1225 | ret = -ENOMEM; | |
1226 | goto out; | |
1227 | } | |
1228 | if (copy_from_user(nc->data, | |
1229 | notification.sigev_value.sival_ptr, | |
1230 | NOTIFY_COOKIE_LEN)) { | |
1231 | ret = -EFAULT; | |
1232 | goto out; | |
1233 | } | |
1234 | ||
1235 | /* TODO: add a header? */ | |
1236 | skb_put(nc, NOTIFY_COOKIE_LEN); | |
1237 | /* and attach it to the socket */ | |
1238 | retry: | |
1239 | f = fdget(notification.sigev_signo); | |
1240 | if (!f.file) { | |
1241 | ret = -EBADF; | |
1242 | goto out; | |
1243 | } | |
1244 | sock = netlink_getsockbyfilp(f.file); | |
1245 | fdput(f); | |
1246 | if (IS_ERR(sock)) { | |
1247 | ret = PTR_ERR(sock); | |
1248 | sock = NULL; | |
1249 | goto out; | |
1250 | } | |
1251 | ||
1252 | timeo = MAX_SCHEDULE_TIMEOUT; | |
1253 | ret = netlink_attachskb(sock, nc, &timeo, NULL); | |
1254 | if (ret == 1) | |
1255 | goto retry; | |
1256 | if (ret) { | |
1257 | sock = NULL; | |
1258 | nc = NULL; | |
1259 | goto out; | |
1260 | } | |
1261 | } | |
1262 | } | |
1263 | ||
1264 | f = fdget(mqdes); | |
1265 | if (!f.file) { | |
1266 | ret = -EBADF; | |
1267 | goto out; | |
1268 | } | |
1269 | ||
1270 | inode = file_inode(f.file); | |
1271 | if (unlikely(f.file->f_op != &mqueue_file_operations)) { | |
1272 | ret = -EBADF; | |
1273 | goto out_fput; | |
1274 | } | |
1275 | info = MQUEUE_I(inode); | |
1276 | ||
1277 | ret = 0; | |
1278 | spin_lock(&info->lock); | |
1279 | if (u_notification == NULL) { | |
1280 | if (info->notify_owner == task_tgid(current)) { | |
1281 | remove_notification(info); | |
1282 | inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
1283 | } | |
1284 | } else if (info->notify_owner != NULL) { | |
1285 | ret = -EBUSY; | |
1286 | } else { | |
1287 | switch (notification.sigev_notify) { | |
1288 | case SIGEV_NONE: | |
1289 | info->notify.sigev_notify = SIGEV_NONE; | |
1290 | break; | |
1291 | case SIGEV_THREAD: | |
1292 | info->notify_sock = sock; | |
1293 | info->notify_cookie = nc; | |
1294 | sock = NULL; | |
1295 | nc = NULL; | |
1296 | info->notify.sigev_notify = SIGEV_THREAD; | |
1297 | break; | |
1298 | case SIGEV_SIGNAL: | |
1299 | info->notify.sigev_signo = notification.sigev_signo; | |
1300 | info->notify.sigev_value = notification.sigev_value; | |
1301 | info->notify.sigev_notify = SIGEV_SIGNAL; | |
1302 | break; | |
1303 | } | |
1304 | ||
1305 | info->notify_owner = get_pid(task_tgid(current)); | |
1306 | info->notify_user_ns = get_user_ns(current_user_ns()); | |
1307 | inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
1308 | } | |
1309 | spin_unlock(&info->lock); | |
1310 | out_fput: | |
1311 | fdput(f); | |
1312 | out: | |
1313 | if (sock) | |
1314 | netlink_detachskb(sock, nc); | |
1315 | else if (nc) | |
1316 | dev_kfree_skb(nc); | |
1317 | ||
1318 | return ret; | |
1319 | } | |
1320 | ||
1321 | SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes, | |
1322 | const struct mq_attr __user *, u_mqstat, | |
1323 | struct mq_attr __user *, u_omqstat) | |
1324 | { | |
1325 | int ret; | |
1326 | struct mq_attr mqstat, omqstat; | |
1327 | struct fd f; | |
1328 | struct inode *inode; | |
1329 | struct mqueue_inode_info *info; | |
1330 | ||
1331 | if (u_mqstat != NULL) { | |
1332 | if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr))) | |
1333 | return -EFAULT; | |
1334 | if (mqstat.mq_flags & (~O_NONBLOCK)) | |
1335 | return -EINVAL; | |
1336 | } | |
1337 | ||
1338 | f = fdget(mqdes); | |
1339 | if (!f.file) { | |
1340 | ret = -EBADF; | |
1341 | goto out; | |
1342 | } | |
1343 | ||
1344 | inode = file_inode(f.file); | |
1345 | if (unlikely(f.file->f_op != &mqueue_file_operations)) { | |
1346 | ret = -EBADF; | |
1347 | goto out_fput; | |
1348 | } | |
1349 | info = MQUEUE_I(inode); | |
1350 | ||
1351 | spin_lock(&info->lock); | |
1352 | ||
1353 | omqstat = info->attr; | |
1354 | omqstat.mq_flags = f.file->f_flags & O_NONBLOCK; | |
1355 | if (u_mqstat) { | |
1356 | audit_mq_getsetattr(mqdes, &mqstat); | |
1357 | spin_lock(&f.file->f_lock); | |
1358 | if (mqstat.mq_flags & O_NONBLOCK) | |
1359 | f.file->f_flags |= O_NONBLOCK; | |
1360 | else | |
1361 | f.file->f_flags &= ~O_NONBLOCK; | |
1362 | spin_unlock(&f.file->f_lock); | |
1363 | ||
1364 | inode->i_atime = inode->i_ctime = CURRENT_TIME; | |
1365 | } | |
1366 | ||
1367 | spin_unlock(&info->lock); | |
1368 | ||
1369 | ret = 0; | |
1370 | if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat, | |
1371 | sizeof(struct mq_attr))) | |
1372 | ret = -EFAULT; | |
1373 | ||
1374 | out_fput: | |
1375 | fdput(f); | |
1376 | out: | |
1377 | return ret; | |
1378 | } | |
1379 | ||
1380 | static const struct inode_operations mqueue_dir_inode_operations = { | |
1381 | .lookup = simple_lookup, | |
1382 | .create = mqueue_create, | |
1383 | .unlink = mqueue_unlink, | |
1384 | }; | |
1385 | ||
1386 | static const struct file_operations mqueue_file_operations = { | |
1387 | .flush = mqueue_flush_file, | |
1388 | .poll = mqueue_poll_file, | |
1389 | .read = mqueue_read_file, | |
1390 | .llseek = default_llseek, | |
1391 | }; | |
1392 | ||
1393 | static const struct super_operations mqueue_super_ops = { | |
1394 | .alloc_inode = mqueue_alloc_inode, | |
1395 | .destroy_inode = mqueue_destroy_inode, | |
1396 | .evict_inode = mqueue_evict_inode, | |
1397 | .statfs = simple_statfs, | |
1398 | }; | |
1399 | ||
1400 | static struct file_system_type mqueue_fs_type = { | |
1401 | .name = "mqueue", | |
1402 | .mount = mqueue_mount, | |
1403 | .kill_sb = kill_litter_super, | |
1404 | .fs_flags = FS_USERNS_MOUNT, | |
1405 | }; | |
1406 | ||
1407 | int mq_init_ns(struct ipc_namespace *ns) | |
1408 | { | |
1409 | ns->mq_queues_count = 0; | |
1410 | ns->mq_queues_max = DFLT_QUEUESMAX; | |
1411 | ns->mq_msg_max = DFLT_MSGMAX; | |
1412 | ns->mq_msgsize_max = DFLT_MSGSIZEMAX; | |
1413 | ns->mq_msg_default = DFLT_MSG; | |
1414 | ns->mq_msgsize_default = DFLT_MSGSIZE; | |
1415 | ||
1416 | ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns); | |
1417 | if (IS_ERR(ns->mq_mnt)) { | |
1418 | int err = PTR_ERR(ns->mq_mnt); | |
1419 | ns->mq_mnt = NULL; | |
1420 | return err; | |
1421 | } | |
1422 | return 0; | |
1423 | } | |
1424 | ||
1425 | void mq_clear_sbinfo(struct ipc_namespace *ns) | |
1426 | { | |
1427 | ns->mq_mnt->mnt_sb->s_fs_info = NULL; | |
1428 | } | |
1429 | ||
1430 | void mq_put_mnt(struct ipc_namespace *ns) | |
1431 | { | |
1432 | kern_unmount(ns->mq_mnt); | |
1433 | } | |
1434 | ||
1435 | static int __init init_mqueue_fs(void) | |
1436 | { | |
1437 | int error; | |
1438 | ||
1439 | mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache", | |
1440 | sizeof(struct mqueue_inode_info), 0, | |
1441 | SLAB_HWCACHE_ALIGN, init_once); | |
1442 | if (mqueue_inode_cachep == NULL) | |
1443 | return -ENOMEM; | |
1444 | ||
1445 | /* ignore failures - they are not fatal */ | |
1446 | mq_sysctl_table = mq_register_sysctl_table(); | |
1447 | ||
1448 | error = register_filesystem(&mqueue_fs_type); | |
1449 | if (error) | |
1450 | goto out_sysctl; | |
1451 | ||
1452 | spin_lock_init(&mq_lock); | |
1453 | ||
1454 | error = mq_init_ns(&init_ipc_ns); | |
1455 | if (error) | |
1456 | goto out_filesystem; | |
1457 | ||
1458 | return 0; | |
1459 | ||
1460 | out_filesystem: | |
1461 | unregister_filesystem(&mqueue_fs_type); | |
1462 | out_sysctl: | |
1463 | if (mq_sysctl_table) | |
1464 | unregister_sysctl_table(mq_sysctl_table); | |
1465 | kmem_cache_destroy(mqueue_inode_cachep); | |
1466 | return error; | |
1467 | } | |
1468 | ||
1469 | device_initcall(init_mqueue_fs); |