blob: 5e785a29e1e63349ff35f8a1b3282f468fd24277 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/ipc/util.c
3 * Copyright (C) 1992 Krishna Balasubramanian
4 *
5 * Sep 1997 - Call suser() last after "normal" permission checks so we
6 * get BSD style process accounting right.
7 * Occurs in several places in the IPC code.
8 * Chris Evans, <chris@ferret.lmh.ox.ac.uk>
9 * Nov 1999 - ipc helper functions, unified SMP locking
Christian Kujau624dffc2006-01-15 02:43:54 +010010 * Manfred Spraul <manfred@colorfullife.com>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
12 * Mingming Cao <cmm@us.ibm.com>
13 */
14
15#include <linux/config.h>
16#include <linux/mm.h>
17#include <linux/shm.h>
18#include <linux/init.h>
19#include <linux/msg.h>
20#include <linux/smp_lock.h>
21#include <linux/vmalloc.h>
22#include <linux/slab.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080023#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <linux/highuid.h>
25#include <linux/security.h>
26#include <linux/rcupdate.h>
27#include <linux/workqueue.h>
Mike Waychisonae781772005-09-06 15:17:09 -070028#include <linux/seq_file.h>
29#include <linux/proc_fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31#include <asm/unistd.h>
32
33#include "util.h"
34
Mike Waychisonae781772005-09-06 15:17:09 -070035struct ipc_proc_iface {
36 const char *path;
37 const char *header;
38 struct ipc_ids *ids;
39 int (*show)(struct seq_file *, void *);
40};
41
Linus Torvalds1da177e2005-04-16 15:20:36 -070042/**
43 * ipc_init - initialise IPC subsystem
44 *
45 * The various system5 IPC resources (semaphores, messages and shared
46 * memory are initialised
47 */
48
49static int __init ipc_init(void)
50{
51 sem_init();
52 msg_init();
53 shm_init();
54 return 0;
55}
56__initcall(ipc_init);
57
58/**
59 * ipc_init_ids - initialise IPC identifiers
60 * @ids: Identifier set
61 * @size: Number of identifiers
62 *
63 * Given a size for the ipc identifier range (limited below IPCMNI)
64 * set up the sequence range to use then allocate and initialise the
65 * array itself.
66 */
67
68void __init ipc_init_ids(struct ipc_ids* ids, int size)
69{
70 int i;
Ingo Molnar5f921ae2006-03-26 01:37:17 -080071
72 mutex_init(&ids->mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
74 if(size > IPCMNI)
75 size = IPCMNI;
76 ids->in_use = 0;
77 ids->max_id = -1;
78 ids->seq = 0;
79 {
80 int seq_limit = INT_MAX/SEQ_MULTIPLIER;
81 if(seq_limit > USHRT_MAX)
82 ids->seq_max = USHRT_MAX;
83 else
84 ids->seq_max = seq_limit;
85 }
86
87 ids->entries = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*size +
88 sizeof(struct ipc_id_ary));
89
90 if(ids->entries == NULL) {
91 printk(KERN_ERR "ipc_init_ids() failed, ipc service disabled.\n");
92 size = 0;
93 ids->entries = &ids->nullentry;
94 }
95 ids->entries->size = size;
96 for(i=0;i<size;i++)
97 ids->entries->p[i] = NULL;
98}
99
Mike Waychisonae781772005-09-06 15:17:09 -0700100#ifdef CONFIG_PROC_FS
101static struct file_operations sysvipc_proc_fops;
102/**
103 * ipc_init_proc_interface - Create a proc interface for sysipc types
104 * using a seq_file interface.
105 * @path: Path in procfs
106 * @header: Banner to be printed at the beginning of the file.
107 * @ids: ipc id table to iterate.
108 * @show: show routine.
109 */
110void __init ipc_init_proc_interface(const char *path, const char *header,
111 struct ipc_ids *ids,
112 int (*show)(struct seq_file *, void *))
113{
114 struct proc_dir_entry *pde;
115 struct ipc_proc_iface *iface;
116
117 iface = kmalloc(sizeof(*iface), GFP_KERNEL);
118 if (!iface)
119 return;
120 iface->path = path;
121 iface->header = header;
122 iface->ids = ids;
123 iface->show = show;
124
125 pde = create_proc_entry(path,
126 S_IRUGO, /* world readable */
127 NULL /* parent dir */);
128 if (pde) {
129 pde->data = iface;
130 pde->proc_fops = &sysvipc_proc_fops;
131 } else {
132 kfree(iface);
133 }
134}
135#endif
136
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137/**
138 * ipc_findkey - find a key in an ipc identifier set
139 * @ids: Identifier set
140 * @key: The key to find
141 *
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800142 * Requires ipc_ids.mutex locked.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 * Returns the identifier if found or -1 if not.
144 */
145
146int ipc_findkey(struct ipc_ids* ids, key_t key)
147{
148 int id;
149 struct kern_ipc_perm* p;
150 int max_id = ids->max_id;
151
152 /*
153 * rcu_dereference() is not needed here
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800154 * since ipc_ids.mutex is held
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 */
156 for (id = 0; id <= max_id; id++) {
157 p = ids->entries->p[id];
158 if(p==NULL)
159 continue;
160 if (key == p->key)
161 return id;
162 }
163 return -1;
164}
165
166/*
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800167 * Requires ipc_ids.mutex locked
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 */
169static int grow_ary(struct ipc_ids* ids, int newsize)
170{
171 struct ipc_id_ary* new;
172 struct ipc_id_ary* old;
173 int i;
174 int size = ids->entries->size;
175
176 if(newsize > IPCMNI)
177 newsize = IPCMNI;
178 if(newsize <= size)
179 return newsize;
180
181 new = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*newsize +
182 sizeof(struct ipc_id_ary));
183 if(new == NULL)
184 return size;
185 new->size = newsize;
186 memcpy(new->p, ids->entries->p, sizeof(struct kern_ipc_perm *)*size +
187 sizeof(struct ipc_id_ary));
188 for(i=size;i<newsize;i++) {
189 new->p[i] = NULL;
190 }
191 old = ids->entries;
192
193 /*
194 * Use rcu_assign_pointer() to make sure the memcpyed contents
195 * of the new array are visible before the new array becomes visible.
196 */
197 rcu_assign_pointer(ids->entries, new);
198
199 ipc_rcu_putref(old);
200 return newsize;
201}
202
203/**
204 * ipc_addid - add an IPC identifier
205 * @ids: IPC identifier set
206 * @new: new IPC permission set
207 * @size: new size limit for the id array
208 *
209 * Add an entry 'new' to the IPC arrays. The permissions object is
210 * initialised and the first free entry is set up and the id assigned
211 * is returned. The list is returned in a locked state on success.
212 * On failure the list is not locked and -1 is returned.
213 *
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800214 * Called with ipc_ids.mutex held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 */
216
217int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size)
218{
219 int id;
220
221 size = grow_ary(ids,size);
222
223 /*
224 * rcu_dereference()() is not needed here since
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800225 * ipc_ids.mutex is held
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 */
227 for (id = 0; id < size; id++) {
228 if(ids->entries->p[id] == NULL)
229 goto found;
230 }
231 return -1;
232found:
233 ids->in_use++;
234 if (id > ids->max_id)
235 ids->max_id = id;
236
237 new->cuid = new->uid = current->euid;
238 new->gid = new->cgid = current->egid;
239
240 new->seq = ids->seq++;
241 if(ids->seq > ids->seq_max)
242 ids->seq = 0;
243
244 spin_lock_init(&new->lock);
245 new->deleted = 0;
246 rcu_read_lock();
247 spin_lock(&new->lock);
248 ids->entries->p[id] = new;
249 return id;
250}
251
252/**
253 * ipc_rmid - remove an IPC identifier
254 * @ids: identifier set
255 * @id: Identifier to remove
256 *
257 * The identifier must be valid, and in use. The kernel will panic if
258 * fed an invalid identifier. The entry is removed and internal
259 * variables recomputed. The object associated with the identifier
260 * is returned.
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800261 * ipc_ids.mutex and the spinlock for this ID is hold before this function
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 * is called, and remain locked on the exit.
263 */
264
265struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id)
266{
267 struct kern_ipc_perm* p;
268 int lid = id % SEQ_MULTIPLIER;
Eric Sesterhenn9bc98fc2006-04-01 01:20:23 +0200269 BUG_ON(lid >= ids->entries->size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270
271 /*
272 * do not need a rcu_dereference()() here to force ordering
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800273 * on Alpha, since the ipc_ids.mutex is held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 */
275 p = ids->entries->p[lid];
276 ids->entries->p[lid] = NULL;
Eric Sesterhenn9bc98fc2006-04-01 01:20:23 +0200277 BUG_ON(p==NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 ids->in_use--;
279
280 if (lid == ids->max_id) {
281 do {
282 lid--;
283 if(lid == -1)
284 break;
285 } while (ids->entries->p[lid] == NULL);
286 ids->max_id = lid;
287 }
288 p->deleted = 1;
289 return p;
290}
291
292/**
293 * ipc_alloc - allocate ipc space
294 * @size: size desired
295 *
296 * Allocate memory from the appropriate pools and return a pointer to it.
297 * NULL is returned if the allocation fails
298 */
299
300void* ipc_alloc(int size)
301{
302 void* out;
303 if(size > PAGE_SIZE)
304 out = vmalloc(size);
305 else
306 out = kmalloc(size, GFP_KERNEL);
307 return out;
308}
309
310/**
311 * ipc_free - free ipc space
312 * @ptr: pointer returned by ipc_alloc
313 * @size: size of block
314 *
315 * Free a block created with ipc_alloc. The caller must know the size
316 * used in the allocation call.
317 */
318
319void ipc_free(void* ptr, int size)
320{
321 if(size > PAGE_SIZE)
322 vfree(ptr);
323 else
324 kfree(ptr);
325}
326
327/*
328 * rcu allocations:
329 * There are three headers that are prepended to the actual allocation:
330 * - during use: ipc_rcu_hdr.
331 * - during the rcu grace period: ipc_rcu_grace.
332 * - [only if vmalloc]: ipc_rcu_sched.
333 * Their lifetime doesn't overlap, thus the headers share the same memory.
334 * Unlike a normal union, they are right-aligned, thus some container_of
335 * forward/backward casting is necessary:
336 */
337struct ipc_rcu_hdr
338{
339 int refcount;
340 int is_vmalloc;
341 void *data[0];
342};
343
344
345struct ipc_rcu_grace
346{
347 struct rcu_head rcu;
348 /* "void *" makes sure alignment of following data is sane. */
349 void *data[0];
350};
351
352struct ipc_rcu_sched
353{
354 struct work_struct work;
355 /* "void *" makes sure alignment of following data is sane. */
356 void *data[0];
357};
358
359#define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \
360 sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr))
361#define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \
362 sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC)
363
364static inline int rcu_use_vmalloc(int size)
365{
366 /* Too big for a single page? */
367 if (HDRLEN_KMALLOC + size > PAGE_SIZE)
368 return 1;
369 return 0;
370}
371
372/**
373 * ipc_rcu_alloc - allocate ipc and rcu space
374 * @size: size desired
375 *
376 * Allocate memory for the rcu header structure + the object.
377 * Returns the pointer to the object.
378 * NULL is returned if the allocation fails.
379 */
380
381void* ipc_rcu_alloc(int size)
382{
383 void* out;
384 /*
385 * We prepend the allocation with the rcu struct, and
386 * workqueue if necessary (for vmalloc).
387 */
388 if (rcu_use_vmalloc(size)) {
389 out = vmalloc(HDRLEN_VMALLOC + size);
390 if (out) {
391 out += HDRLEN_VMALLOC;
392 container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1;
393 container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
394 }
395 } else {
396 out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL);
397 if (out) {
398 out += HDRLEN_KMALLOC;
399 container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0;
400 container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
401 }
402 }
403
404 return out;
405}
406
407void ipc_rcu_getref(void *ptr)
408{
409 container_of(ptr, struct ipc_rcu_hdr, data)->refcount++;
410}
411
412/**
Randy Dunlap1e5d5332005-11-07 01:01:06 -0800413 * ipc_schedule_free - free ipc + rcu space
414 * @head: RCU callback structure for queued work
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 *
416 * Since RCU callback function is called in bh,
417 * we need to defer the vfree to schedule_work
418 */
419static void ipc_schedule_free(struct rcu_head *head)
420{
421 struct ipc_rcu_grace *grace =
422 container_of(head, struct ipc_rcu_grace, rcu);
423 struct ipc_rcu_sched *sched =
424 container_of(&(grace->data[0]), struct ipc_rcu_sched, data[0]);
425
426 INIT_WORK(&sched->work, vfree, sched);
427 schedule_work(&sched->work);
428}
429
430/**
Randy Dunlap1e5d5332005-11-07 01:01:06 -0800431 * ipc_immediate_free - free ipc + rcu space
432 * @head: RCU callback structure that contains pointer to be freed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 *
Randy Dunlap1e5d5332005-11-07 01:01:06 -0800434 * Free from the RCU callback context
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435 */
436static void ipc_immediate_free(struct rcu_head *head)
437{
438 struct ipc_rcu_grace *free =
439 container_of(head, struct ipc_rcu_grace, rcu);
440 kfree(free);
441}
442
443void ipc_rcu_putref(void *ptr)
444{
445 if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0)
446 return;
447
448 if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) {
449 call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
450 ipc_schedule_free);
451 } else {
452 call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
453 ipc_immediate_free);
454 }
455}
456
457/**
458 * ipcperms - check IPC permissions
459 * @ipcp: IPC permission set
460 * @flag: desired permission set.
461 *
462 * Check user, group, other permissions for access
463 * to ipc resources. return 0 if allowed
464 */
465
466int ipcperms (struct kern_ipc_perm *ipcp, short flag)
467{ /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */
468 int requested_mode, granted_mode;
469
470 requested_mode = (flag >> 6) | (flag >> 3) | flag;
471 granted_mode = ipcp->mode;
472 if (current->euid == ipcp->cuid || current->euid == ipcp->uid)
473 granted_mode >>= 6;
474 else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
475 granted_mode >>= 3;
476 /* is there some bit set in requested_mode but not in granted_mode? */
477 if ((requested_mode & ~granted_mode & 0007) &&
478 !capable(CAP_IPC_OWNER))
479 return -1;
480
481 return security_ipc_permission(ipcp, flag);
482}
483
484/*
485 * Functions to convert between the kern_ipc_perm structure and the
486 * old/new ipc_perm structures
487 */
488
489/**
490 * kernel_to_ipc64_perm - convert kernel ipc permissions to user
491 * @in: kernel permissions
492 * @out: new style IPC permissions
493 *
494 * Turn the kernel object 'in' into a set of permissions descriptions
495 * for returning to userspace (out).
496 */
497
498
499void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out)
500{
501 out->key = in->key;
502 out->uid = in->uid;
503 out->gid = in->gid;
504 out->cuid = in->cuid;
505 out->cgid = in->cgid;
506 out->mode = in->mode;
507 out->seq = in->seq;
508}
509
510/**
511 * ipc64_perm_to_ipc_perm - convert old ipc permissions to new
512 * @in: new style IPC permissions
513 * @out: old style IPC permissions
514 *
515 * Turn the new style permissions object in into a compatibility
516 * object and store it into the 'out' pointer.
517 */
518
519void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out)
520{
521 out->key = in->key;
522 SET_UID(out->uid, in->uid);
523 SET_GID(out->gid, in->gid);
524 SET_UID(out->cuid, in->cuid);
525 SET_GID(out->cgid, in->cgid);
526 out->mode = in->mode;
527 out->seq = in->seq;
528}
529
530/*
531 * So far only shm_get_stat() calls ipc_get() via shm_get(), so ipc_get()
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800532 * is called with shm_ids.mutex locked. Since grow_ary() is also called with
533 * shm_ids.mutex down(for Shared Memory), there is no need to add read
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 * barriers here to gurantee the writes in grow_ary() are seen in order
535 * here (for Alpha).
536 *
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800537 * However ipc_get() itself does not necessary require ipc_ids.mutex down. So
538 * if in the future ipc_get() is used by other places without ipc_ids.mutex
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 * down, then ipc_get() needs read memery barriers as ipc_lock() does.
540 */
541struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id)
542{
543 struct kern_ipc_perm* out;
544 int lid = id % SEQ_MULTIPLIER;
545 if(lid >= ids->entries->size)
546 return NULL;
547 out = ids->entries->p[lid];
548 return out;
549}
550
551struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id)
552{
553 struct kern_ipc_perm* out;
554 int lid = id % SEQ_MULTIPLIER;
555 struct ipc_id_ary* entries;
556
557 rcu_read_lock();
558 entries = rcu_dereference(ids->entries);
559 if(lid >= entries->size) {
560 rcu_read_unlock();
561 return NULL;
562 }
563 out = entries->p[lid];
564 if(out == NULL) {
565 rcu_read_unlock();
566 return NULL;
567 }
568 spin_lock(&out->lock);
569
570 /* ipc_rmid() may have already freed the ID while ipc_lock
571 * was spinning: here verify that the structure is still valid
572 */
573 if (out->deleted) {
574 spin_unlock(&out->lock);
575 rcu_read_unlock();
576 return NULL;
577 }
578 return out;
579}
580
581void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
582{
583 rcu_read_lock();
584 spin_lock(&perm->lock);
585}
586
587void ipc_unlock(struct kern_ipc_perm* perm)
588{
589 spin_unlock(&perm->lock);
590 rcu_read_unlock();
591}
592
593int ipc_buildid(struct ipc_ids* ids, int id, int seq)
594{
595 return SEQ_MULTIPLIER*seq + id;
596}
597
598int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid)
599{
600 if(uid/SEQ_MULTIPLIER != ipcp->seq)
601 return 1;
602 return 0;
603}
604
605#ifdef __ARCH_WANT_IPC_PARSE_VERSION
606
607
608/**
609 * ipc_parse_version - IPC call version
610 * @cmd: pointer to command
611 *
612 * Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
613 * The cmd value is turned from an encoding command and version into
614 * just the command code.
615 */
616
617int ipc_parse_version (int *cmd)
618{
619 if (*cmd & IPC_64) {
620 *cmd ^= IPC_64;
621 return IPC_64;
622 } else {
623 return IPC_OLD;
624 }
625}
626
627#endif /* __ARCH_WANT_IPC_PARSE_VERSION */
Mike Waychisonae781772005-09-06 15:17:09 -0700628
629#ifdef CONFIG_PROC_FS
630static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
631{
632 struct ipc_proc_iface *iface = s->private;
633 struct kern_ipc_perm *ipc = it;
634 loff_t p;
635
636 /* If we had an ipc id locked before, unlock it */
637 if (ipc && ipc != SEQ_START_TOKEN)
638 ipc_unlock(ipc);
639
640 /*
641 * p = *pos - 1 (because id 0 starts at position 1)
642 * + 1 (because we increment the position by one)
643 */
644 for (p = *pos; p <= iface->ids->max_id; p++) {
645 if ((ipc = ipc_lock(iface->ids, p)) != NULL) {
646 *pos = p + 1;
647 return ipc;
648 }
649 }
650
651 /* Out of range - return NULL to terminate iteration */
652 return NULL;
653}
654
655/*
656 * File positions: pos 0 -> header, pos n -> ipc id + 1.
657 * SeqFile iterator: iterator value locked shp or SEQ_TOKEN_START.
658 */
659static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
660{
661 struct ipc_proc_iface *iface = s->private;
662 struct kern_ipc_perm *ipc;
663 loff_t p;
664
665 /*
666 * Take the lock - this will be released by the corresponding
667 * call to stop().
668 */
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800669 mutex_lock(&iface->ids->mutex);
Mike Waychisonae781772005-09-06 15:17:09 -0700670
671 /* pos < 0 is invalid */
672 if (*pos < 0)
673 return NULL;
674
675 /* pos == 0 means header */
676 if (*pos == 0)
677 return SEQ_START_TOKEN;
678
679 /* Find the (pos-1)th ipc */
680 for (p = *pos - 1; p <= iface->ids->max_id; p++) {
681 if ((ipc = ipc_lock(iface->ids, p)) != NULL) {
682 *pos = p + 1;
683 return ipc;
684 }
685 }
686 return NULL;
687}
688
689static void sysvipc_proc_stop(struct seq_file *s, void *it)
690{
691 struct kern_ipc_perm *ipc = it;
692 struct ipc_proc_iface *iface = s->private;
693
694 /* If we had a locked segment, release it */
695 if (ipc && ipc != SEQ_START_TOKEN)
696 ipc_unlock(ipc);
697
698 /* Release the lock we took in start() */
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800699 mutex_unlock(&iface->ids->mutex);
Mike Waychisonae781772005-09-06 15:17:09 -0700700}
701
702static int sysvipc_proc_show(struct seq_file *s, void *it)
703{
704 struct ipc_proc_iface *iface = s->private;
705
706 if (it == SEQ_START_TOKEN)
707 return seq_puts(s, iface->header);
708
709 return iface->show(s, it);
710}
711
712static struct seq_operations sysvipc_proc_seqops = {
713 .start = sysvipc_proc_start,
714 .stop = sysvipc_proc_stop,
715 .next = sysvipc_proc_next,
716 .show = sysvipc_proc_show,
717};
718
719static int sysvipc_proc_open(struct inode *inode, struct file *file) {
720 int ret;
721 struct seq_file *seq;
722
723 ret = seq_open(file, &sysvipc_proc_seqops);
724 if (!ret) {
725 seq = file->private_data;
726 seq->private = PDE(inode)->data;
727 }
728 return ret;
729}
730
731static struct file_operations sysvipc_proc_fops = {
732 .open = sysvipc_proc_open,
733 .read = seq_read,
734 .llseek = seq_lseek,
735 .release = seq_release,
736};
737#endif /* CONFIG_PROC_FS */