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CommitLineData
1da177e4
LT
1/*
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
624dffcb 10 * Manfred Spraul <manfred@colorfullife.com>
1da177e4
LT
11 * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
12 * Mingming Cao <cmm@us.ibm.com>
073115d6
SG
13 * Mar 2006 - support for audit of ipc object properties
14 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
73ea4130
KK
15 * Jun 2006 - namespaces ssupport
16 * OpenVZ, SWsoft Inc.
17 * Pavel Emelianov <xemul@openvz.org>
1da177e4
LT
18 */
19
1da177e4
LT
20#include <linux/mm.h>
21#include <linux/shm.h>
22#include <linux/init.h>
23#include <linux/msg.h>
1da177e4
LT
24#include <linux/vmalloc.h>
25#include <linux/slab.h>
c59ede7b 26#include <linux/capability.h>
1da177e4
LT
27#include <linux/highuid.h>
28#include <linux/security.h>
29#include <linux/rcupdate.h>
30#include <linux/workqueue.h>
ae781774
MW
31#include <linux/seq_file.h>
32#include <linux/proc_fs.h>
073115d6 33#include <linux/audit.h>
73ea4130 34#include <linux/nsproxy.h>
1da177e4
LT
35
36#include <asm/unistd.h>
37
38#include "util.h"
39
ae781774
MW
40struct ipc_proc_iface {
41 const char *path;
42 const char *header;
73ea4130 43 int ids;
ae781774
MW
44 int (*show)(struct seq_file *, void *);
45};
46
73ea4130
KK
47struct ipc_namespace init_ipc_ns = {
48 .kref = {
49 .refcount = ATOMIC_INIT(2),
50 },
51};
52
73ea4130
KK
53static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
54{
55 int err;
56 struct ipc_namespace *ns;
57
58 err = -ENOMEM;
59 ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
60 if (ns == NULL)
61 goto err_mem;
62
63 err = sem_init_ns(ns);
64 if (err)
65 goto err_sem;
66 err = msg_init_ns(ns);
67 if (err)
68 goto err_msg;
69 err = shm_init_ns(ns);
70 if (err)
71 goto err_shm;
72
73 kref_init(&ns->kref);
74 return ns;
75
76err_shm:
77 msg_exit_ns(ns);
78err_msg:
79 sem_exit_ns(ns);
80err_sem:
81 kfree(ns);
82err_mem:
83 return ERR_PTR(err);
84}
85
e3222c4e 86struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
73ea4130 87{
73ea4130 88 struct ipc_namespace *new_ns;
73ea4130 89
e3222c4e
BP
90 BUG_ON(!ns);
91 get_ipc_ns(ns);
73ea4130
KK
92
93 if (!(flags & CLONE_NEWIPC))
e3222c4e
BP
94 return ns;
95
96 new_ns = clone_ipc_ns(ns);
97
98 put_ipc_ns(ns);
99 return new_ns;
73ea4130
KK
100}
101
102void free_ipc_ns(struct kref *kref)
103{
104 struct ipc_namespace *ns;
105
106 ns = container_of(kref, struct ipc_namespace, kref);
107 sem_exit_ns(ns);
108 msg_exit_ns(ns);
109 shm_exit_ns(ns);
110 kfree(ns);
111}
73ea4130 112
1da177e4
LT
113/**
114 * ipc_init - initialise IPC subsystem
115 *
116 * The various system5 IPC resources (semaphores, messages and shared
72fd4a35 117 * memory) are initialised
1da177e4
LT
118 */
119
120static int __init ipc_init(void)
121{
122 sem_init();
123 msg_init();
124 shm_init();
125 return 0;
126}
127__initcall(ipc_init);
128
129/**
130 * ipc_init_ids - initialise IPC identifiers
131 * @ids: Identifier set
1da177e4 132 *
7ca7e564
ND
133 * Set up the sequence range to use for the ipc identifier range (limited
134 * below IPCMNI) then initialise the ids idr.
1da177e4
LT
135 */
136
7ca7e564 137void ipc_init_ids(struct ipc_ids *ids)
1da177e4 138{
5f921ae9 139 mutex_init(&ids->mutex);
1da177e4 140
1da177e4 141 ids->in_use = 0;
1da177e4
LT
142 ids->seq = 0;
143 {
144 int seq_limit = INT_MAX/SEQ_MULTIPLIER;
145 if(seq_limit > USHRT_MAX)
146 ids->seq_max = USHRT_MAX;
147 else
148 ids->seq_max = seq_limit;
149 }
150
7ca7e564 151 idr_init(&ids->ipcs_idr);
1da177e4
LT
152}
153
ae781774 154#ifdef CONFIG_PROC_FS
9a32144e 155static const struct file_operations sysvipc_proc_fops;
ae781774 156/**
72fd4a35 157 * ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface.
ae781774
MW
158 * @path: Path in procfs
159 * @header: Banner to be printed at the beginning of the file.
160 * @ids: ipc id table to iterate.
161 * @show: show routine.
162 */
163void __init ipc_init_proc_interface(const char *path, const char *header,
73ea4130 164 int ids, int (*show)(struct seq_file *, void *))
ae781774
MW
165{
166 struct proc_dir_entry *pde;
167 struct ipc_proc_iface *iface;
168
169 iface = kmalloc(sizeof(*iface), GFP_KERNEL);
170 if (!iface)
171 return;
172 iface->path = path;
173 iface->header = header;
174 iface->ids = ids;
175 iface->show = show;
176
177 pde = create_proc_entry(path,
178 S_IRUGO, /* world readable */
179 NULL /* parent dir */);
180 if (pde) {
181 pde->data = iface;
182 pde->proc_fops = &sysvipc_proc_fops;
183 } else {
184 kfree(iface);
185 }
186}
187#endif
188
1da177e4
LT
189/**
190 * ipc_findkey - find a key in an ipc identifier set
191 * @ids: Identifier set
192 * @key: The key to find
193 *
5f921ae9 194 * Requires ipc_ids.mutex locked.
7ca7e564
ND
195 * Returns the LOCKED pointer to the ipc structure if found or NULL
196 * if not.
197 * If key is found ipc contains its ipc structure
1da177e4
LT
198 */
199
7748dbfa 200static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
1da177e4 201{
7ca7e564
ND
202 struct kern_ipc_perm *ipc;
203 int next_id;
204 int total;
1da177e4 205
7ca7e564
ND
206 for (total = 0, next_id = 0; total < ids->in_use; next_id++) {
207 ipc = idr_find(&ids->ipcs_idr, next_id);
208
209 if (ipc == NULL)
1da177e4 210 continue;
7ca7e564
ND
211
212 if (ipc->key != key) {
213 total++;
214 continue;
215 }
216
217 ipc_lock_by_ptr(ipc);
218 return ipc;
1da177e4 219 }
7ca7e564
ND
220
221 return NULL;
1da177e4
LT
222}
223
7ca7e564
ND
224/**
225 * ipc_get_maxid - get the last assigned id
226 * @ids: IPC identifier set
227 *
228 * Called with ipc_ids.mutex held.
1da177e4 229 */
1da177e4 230
7ca7e564
ND
231int ipc_get_maxid(struct ipc_ids *ids)
232{
233 struct kern_ipc_perm *ipc;
234 int max_id = -1;
235 int total, id;
236
237 if (ids->in_use == 0)
238 return -1;
1da177e4 239
7ca7e564
ND
240 if (ids->in_use == IPCMNI)
241 return IPCMNI - 1;
242
243 /* Look for the last assigned id */
244 total = 0;
245 for (id = 0; id < IPCMNI && total < ids->in_use; id++) {
246 ipc = idr_find(&ids->ipcs_idr, id);
247 if (ipc != NULL) {
248 max_id = id;
249 total++;
250 }
251 }
252 return max_id;
1da177e4
LT
253}
254
255/**
256 * ipc_addid - add an IPC identifier
257 * @ids: IPC identifier set
258 * @new: new IPC permission set
7ca7e564 259 * @size: limit for the number of used ids
1da177e4 260 *
7ca7e564 261 * Add an entry 'new' to the IPC idr. The permissions object is
1da177e4
LT
262 * initialised and the first free entry is set up and the id assigned
263 * is returned. The list is returned in a locked state on success.
264 * On failure the list is not locked and -1 is returned.
265 *
5f921ae9 266 * Called with ipc_ids.mutex held.
1da177e4
LT
267 */
268
269int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size)
270{
7ca7e564 271 int id, err;
1da177e4
LT
272
273 /*
274 * rcu_dereference()() is not needed here since
5f921ae9 275 * ipc_ids.mutex is held
1da177e4 276 */
7ca7e564
ND
277 if (size > IPCMNI)
278 size = IPCMNI;
279
280 if (ids->in_use >= size)
281 return -1;
282
283 err = idr_get_new(&ids->ipcs_idr, new, &id);
284 if (err)
285 return -1;
286
1da177e4 287 ids->in_use++;
1da177e4
LT
288
289 new->cuid = new->uid = current->euid;
290 new->gid = new->cgid = current->egid;
291
292 new->seq = ids->seq++;
293 if(ids->seq > ids->seq_max)
294 ids->seq = 0;
295
296 spin_lock_init(&new->lock);
297 new->deleted = 0;
298 rcu_read_lock();
299 spin_lock(&new->lock);
1da177e4
LT
300 return id;
301}
302
7748dbfa
ND
303/**
304 * ipcget_new - create a new ipc object
305 * @ns: namespace
306 * @ids: identifer set
307 * @ops: the actual creation routine to call
308 * @params: its parameters
309 *
310 * This routine is called sys_msgget, sys_semget() and sys_shmget() when
311 * the key is IPC_PRIVATE
312 */
313int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
314 struct ipc_ops *ops, struct ipc_params *params)
315{
316 int err;
317
318 err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);
319
320 if (!err)
321 return -ENOMEM;
322
323 mutex_lock(&ids->mutex);
324 err = ops->getnew(ns, params);
325 mutex_unlock(&ids->mutex);
326
327 return err;
328}
329
330/**
331 * ipc_check_perms - check security and permissions for an IPC
332 * @ipcp: ipc permission set
333 * @ids: identifer set
334 * @ops: the actual security routine to call
335 * @params: its parameters
336 */
337static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops,
338 struct ipc_params *params)
339{
340 int err;
341
342 if (ipcperms(ipcp, params->flg))
343 err = -EACCES;
344 else {
345 err = ops->associate(ipcp, params->flg);
346 if (!err)
347 err = ipcp->id;
348 }
349
350 return err;
351}
352
353/**
354 * ipcget_public - get an ipc object or create a new one
355 * @ns: namespace
356 * @ids: identifer set
357 * @ops: the actual creation routine to call
358 * @params: its parameters
359 *
360 * This routine is called sys_msgget, sys_semget() and sys_shmget() when
361 * the key is not IPC_PRIVATE
362 */
363int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
364 struct ipc_ops *ops, struct ipc_params *params)
365{
366 struct kern_ipc_perm *ipcp;
367 int flg = params->flg;
368 int err;
369
370 err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);
371
372 mutex_lock(&ids->mutex);
373 ipcp = ipc_findkey(ids, params->key);
374 if (ipcp == NULL) {
375 /* key not used */
376 if (!(flg & IPC_CREAT))
377 err = -ENOENT;
378 else if (!err)
379 err = -ENOMEM;
380 else
381 err = ops->getnew(ns, params);
382 } else {
383 /* ipc object has been locked by ipc_findkey() */
384
385 if (flg & IPC_CREAT && flg & IPC_EXCL)
386 err = -EEXIST;
387 else {
388 err = 0;
389 if (ops->more_checks)
390 err = ops->more_checks(ipcp, params);
391 if (!err)
392 err = ipc_check_perms(ipcp, ops, params);
393 }
394 ipc_unlock(ipcp);
395 }
396 mutex_unlock(&ids->mutex);
397
398 return err;
399}
400
401
1da177e4
LT
402/**
403 * ipc_rmid - remove an IPC identifier
404 * @ids: identifier set
7ca7e564 405 * @id: ipc perm structure containing the identifier to remove
1da177e4
LT
406 *
407 * The identifier must be valid, and in use. The kernel will panic if
408 * fed an invalid identifier. The entry is removed and internal
7ca7e564
ND
409 * variables recomputed.
410 * ipc_ids.mutex and the spinlock for this ID are held before this
411 * function is called, and remain locked on the exit.
1da177e4
LT
412 */
413
7ca7e564 414void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
1da177e4 415{
7ca7e564
ND
416 int lid = ipcp->id % SEQ_MULTIPLIER;
417
418 idr_remove(&ids->ipcs_idr, lid);
1da177e4 419
1da177e4
LT
420 ids->in_use--;
421
7ca7e564
ND
422 ipcp->deleted = 1;
423
424 return;
1da177e4
LT
425}
426
427/**
428 * ipc_alloc - allocate ipc space
429 * @size: size desired
430 *
431 * Allocate memory from the appropriate pools and return a pointer to it.
432 * NULL is returned if the allocation fails
433 */
434
435void* ipc_alloc(int size)
436{
437 void* out;
438 if(size > PAGE_SIZE)
439 out = vmalloc(size);
440 else
441 out = kmalloc(size, GFP_KERNEL);
442 return out;
443}
444
445/**
446 * ipc_free - free ipc space
447 * @ptr: pointer returned by ipc_alloc
448 * @size: size of block
449 *
72fd4a35 450 * Free a block created with ipc_alloc(). The caller must know the size
1da177e4
LT
451 * used in the allocation call.
452 */
453
454void ipc_free(void* ptr, int size)
455{
456 if(size > PAGE_SIZE)
457 vfree(ptr);
458 else
459 kfree(ptr);
460}
461
462/*
463 * rcu allocations:
464 * There are three headers that are prepended to the actual allocation:
465 * - during use: ipc_rcu_hdr.
466 * - during the rcu grace period: ipc_rcu_grace.
467 * - [only if vmalloc]: ipc_rcu_sched.
468 * Their lifetime doesn't overlap, thus the headers share the same memory.
469 * Unlike a normal union, they are right-aligned, thus some container_of
470 * forward/backward casting is necessary:
471 */
472struct ipc_rcu_hdr
473{
474 int refcount;
475 int is_vmalloc;
476 void *data[0];
477};
478
479
480struct ipc_rcu_grace
481{
482 struct rcu_head rcu;
483 /* "void *" makes sure alignment of following data is sane. */
484 void *data[0];
485};
486
487struct ipc_rcu_sched
488{
489 struct work_struct work;
490 /* "void *" makes sure alignment of following data is sane. */
491 void *data[0];
492};
493
494#define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \
495 sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr))
496#define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \
497 sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC)
498
499static inline int rcu_use_vmalloc(int size)
500{
501 /* Too big for a single page? */
502 if (HDRLEN_KMALLOC + size > PAGE_SIZE)
503 return 1;
504 return 0;
505}
506
507/**
508 * ipc_rcu_alloc - allocate ipc and rcu space
509 * @size: size desired
510 *
511 * Allocate memory for the rcu header structure + the object.
512 * Returns the pointer to the object.
513 * NULL is returned if the allocation fails.
514 */
515
516void* ipc_rcu_alloc(int size)
517{
518 void* out;
519 /*
520 * We prepend the allocation with the rcu struct, and
521 * workqueue if necessary (for vmalloc).
522 */
523 if (rcu_use_vmalloc(size)) {
524 out = vmalloc(HDRLEN_VMALLOC + size);
525 if (out) {
526 out += HDRLEN_VMALLOC;
527 container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1;
528 container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
529 }
530 } else {
531 out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL);
532 if (out) {
533 out += HDRLEN_KMALLOC;
534 container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0;
535 container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
536 }
537 }
538
539 return out;
540}
541
542void ipc_rcu_getref(void *ptr)
543{
544 container_of(ptr, struct ipc_rcu_hdr, data)->refcount++;
545}
546
65f27f38
DH
547static void ipc_do_vfree(struct work_struct *work)
548{
549 vfree(container_of(work, struct ipc_rcu_sched, work));
550}
551
1da177e4 552/**
1e5d5331
RD
553 * ipc_schedule_free - free ipc + rcu space
554 * @head: RCU callback structure for queued work
1da177e4
LT
555 *
556 * Since RCU callback function is called in bh,
72fd4a35 557 * we need to defer the vfree to schedule_work().
1da177e4
LT
558 */
559static void ipc_schedule_free(struct rcu_head *head)
560{
561 struct ipc_rcu_grace *grace =
562 container_of(head, struct ipc_rcu_grace, rcu);
563 struct ipc_rcu_sched *sched =
564 container_of(&(grace->data[0]), struct ipc_rcu_sched, data[0]);
565
65f27f38 566 INIT_WORK(&sched->work, ipc_do_vfree);
1da177e4
LT
567 schedule_work(&sched->work);
568}
569
570/**
1e5d5331
RD
571 * ipc_immediate_free - free ipc + rcu space
572 * @head: RCU callback structure that contains pointer to be freed
1da177e4 573 *
72fd4a35 574 * Free from the RCU callback context.
1da177e4
LT
575 */
576static void ipc_immediate_free(struct rcu_head *head)
577{
578 struct ipc_rcu_grace *free =
579 container_of(head, struct ipc_rcu_grace, rcu);
580 kfree(free);
581}
582
583void ipc_rcu_putref(void *ptr)
584{
585 if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0)
586 return;
587
588 if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) {
589 call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
590 ipc_schedule_free);
591 } else {
592 call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
593 ipc_immediate_free);
594 }
595}
596
597/**
598 * ipcperms - check IPC permissions
599 * @ipcp: IPC permission set
600 * @flag: desired permission set.
601 *
602 * Check user, group, other permissions for access
603 * to ipc resources. return 0 if allowed
604 */
605
606int ipcperms (struct kern_ipc_perm *ipcp, short flag)
607{ /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */
073115d6 608 int requested_mode, granted_mode, err;
1da177e4 609
073115d6
SG
610 if (unlikely((err = audit_ipc_obj(ipcp))))
611 return err;
1da177e4
LT
612 requested_mode = (flag >> 6) | (flag >> 3) | flag;
613 granted_mode = ipcp->mode;
614 if (current->euid == ipcp->cuid || current->euid == ipcp->uid)
615 granted_mode >>= 6;
616 else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
617 granted_mode >>= 3;
618 /* is there some bit set in requested_mode but not in granted_mode? */
619 if ((requested_mode & ~granted_mode & 0007) &&
620 !capable(CAP_IPC_OWNER))
621 return -1;
622
623 return security_ipc_permission(ipcp, flag);
624}
625
626/*
627 * Functions to convert between the kern_ipc_perm structure and the
628 * old/new ipc_perm structures
629 */
630
631/**
632 * kernel_to_ipc64_perm - convert kernel ipc permissions to user
633 * @in: kernel permissions
634 * @out: new style IPC permissions
635 *
72fd4a35
RD
636 * Turn the kernel object @in into a set of permissions descriptions
637 * for returning to userspace (@out).
1da177e4
LT
638 */
639
640
641void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out)
642{
643 out->key = in->key;
644 out->uid = in->uid;
645 out->gid = in->gid;
646 out->cuid = in->cuid;
647 out->cgid = in->cgid;
648 out->mode = in->mode;
649 out->seq = in->seq;
650}
651
652/**
653 * ipc64_perm_to_ipc_perm - convert old ipc permissions to new
654 * @in: new style IPC permissions
655 * @out: old style IPC permissions
656 *
72fd4a35
RD
657 * Turn the new style permissions object @in into a compatibility
658 * object and store it into the @out pointer.
1da177e4
LT
659 */
660
661void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out)
662{
663 out->key = in->key;
664 SET_UID(out->uid, in->uid);
665 SET_GID(out->gid, in->gid);
666 SET_UID(out->cuid, in->cuid);
667 SET_GID(out->cgid, in->cgid);
668 out->mode = in->mode;
669 out->seq = in->seq;
670}
671
7ca7e564 672struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
1da177e4 673{
7ca7e564 674 struct kern_ipc_perm *out;
1da177e4 675 int lid = id % SEQ_MULTIPLIER;
1da177e4
LT
676
677 rcu_read_lock();
7ca7e564
ND
678 out = idr_find(&ids->ipcs_idr, lid);
679 if (out == NULL) {
1da177e4 680 rcu_read_unlock();
023a5355 681 return ERR_PTR(-EINVAL);
1da177e4 682 }
7ca7e564 683
1da177e4
LT
684 spin_lock(&out->lock);
685
686 /* ipc_rmid() may have already freed the ID while ipc_lock
687 * was spinning: here verify that the structure is still valid
688 */
689 if (out->deleted) {
690 spin_unlock(&out->lock);
691 rcu_read_unlock();
023a5355 692 return ERR_PTR(-EINVAL);
1da177e4 693 }
7ca7e564 694
1da177e4
LT
695 return out;
696}
697
1da177e4
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698int ipc_buildid(struct ipc_ids* ids, int id, int seq)
699{
700 return SEQ_MULTIPLIER*seq + id;
701}
702
1da177e4
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703#ifdef __ARCH_WANT_IPC_PARSE_VERSION
704
705
706/**
707 * ipc_parse_version - IPC call version
708 * @cmd: pointer to command
709 *
710 * Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
72fd4a35 711 * The @cmd value is turned from an encoding command and version into
1da177e4
LT
712 * just the command code.
713 */
714
715int ipc_parse_version (int *cmd)
716{
717 if (*cmd & IPC_64) {
718 *cmd ^= IPC_64;
719 return IPC_64;
720 } else {
721 return IPC_OLD;
722 }
723}
724
725#endif /* __ARCH_WANT_IPC_PARSE_VERSION */
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726
727#ifdef CONFIG_PROC_FS
bc1fc6d8
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728struct ipc_proc_iter {
729 struct ipc_namespace *ns;
730 struct ipc_proc_iface *iface;
731};
732
7ca7e564
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733/*
734 * This routine locks the ipc structure found at least at position pos.
735 */
736struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
737 loff_t *new_pos)
ae781774 738{
7ca7e564
ND
739 struct kern_ipc_perm *ipc;
740 int total, id;
73ea4130 741
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742 total = 0;
743 for (id = 0; id < pos && total < ids->in_use; id++) {
744 ipc = idr_find(&ids->ipcs_idr, id);
745 if (ipc != NULL)
746 total++;
747 }
ae781774 748
7ca7e564
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749 if (total >= ids->in_use)
750 return NULL;
ae781774 751
7ca7e564
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752 for ( ; pos < IPCMNI; pos++) {
753 ipc = idr_find(&ids->ipcs_idr, pos);
754 if (ipc != NULL) {
755 *new_pos = pos + 1;
756 ipc_lock_by_ptr(ipc);
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757 return ipc;
758 }
759 }
760
761 /* Out of range - return NULL to terminate iteration */
762 return NULL;
763}
764
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765static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
766{
767 struct ipc_proc_iter *iter = s->private;
768 struct ipc_proc_iface *iface = iter->iface;
769 struct kern_ipc_perm *ipc = it;
770
771 /* If we had an ipc id locked before, unlock it */
772 if (ipc && ipc != SEQ_START_TOKEN)
773 ipc_unlock(ipc);
774
775 return sysvipc_find_ipc(iter->ns->ids[iface->ids], *pos, pos);
776}
777
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778/*
779 * File positions: pos 0 -> header, pos n -> ipc id + 1.
780 * SeqFile iterator: iterator value locked shp or SEQ_TOKEN_START.
781 */
782static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
783{
bc1fc6d8
EB
784 struct ipc_proc_iter *iter = s->private;
785 struct ipc_proc_iface *iface = iter->iface;
73ea4130
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786 struct ipc_ids *ids;
787
bc1fc6d8 788 ids = iter->ns->ids[iface->ids];
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789
790 /*
791 * Take the lock - this will be released by the corresponding
792 * call to stop().
793 */
73ea4130 794 mutex_lock(&ids->mutex);
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795
796 /* pos < 0 is invalid */
797 if (*pos < 0)
798 return NULL;
799
800 /* pos == 0 means header */
801 if (*pos == 0)
802 return SEQ_START_TOKEN;
803
804 /* Find the (pos-1)th ipc */
7ca7e564 805 return sysvipc_find_ipc(ids, *pos - 1, pos);
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806}
807
808static void sysvipc_proc_stop(struct seq_file *s, void *it)
809{
810 struct kern_ipc_perm *ipc = it;
bc1fc6d8
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811 struct ipc_proc_iter *iter = s->private;
812 struct ipc_proc_iface *iface = iter->iface;
73ea4130 813 struct ipc_ids *ids;
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814
815 /* If we had a locked segment, release it */
816 if (ipc && ipc != SEQ_START_TOKEN)
817 ipc_unlock(ipc);
818
bc1fc6d8 819 ids = iter->ns->ids[iface->ids];
ae781774 820 /* Release the lock we took in start() */
73ea4130 821 mutex_unlock(&ids->mutex);
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822}
823
824static int sysvipc_proc_show(struct seq_file *s, void *it)
825{
bc1fc6d8
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826 struct ipc_proc_iter *iter = s->private;
827 struct ipc_proc_iface *iface = iter->iface;
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828
829 if (it == SEQ_START_TOKEN)
830 return seq_puts(s, iface->header);
831
832 return iface->show(s, it);
833}
834
835static struct seq_operations sysvipc_proc_seqops = {
836 .start = sysvipc_proc_start,
837 .stop = sysvipc_proc_stop,
838 .next = sysvipc_proc_next,
839 .show = sysvipc_proc_show,
840};
841
bc1fc6d8
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842static int sysvipc_proc_open(struct inode *inode, struct file *file)
843{
ae781774
MW
844 int ret;
845 struct seq_file *seq;
bc1fc6d8
EB
846 struct ipc_proc_iter *iter;
847
848 ret = -ENOMEM;
849 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
850 if (!iter)
851 goto out;
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852
853 ret = seq_open(file, &sysvipc_proc_seqops);
bc1fc6d8
EB
854 if (ret)
855 goto out_kfree;
856
857 seq = file->private_data;
858 seq->private = iter;
859
860 iter->iface = PDE(inode)->data;
861 iter->ns = get_ipc_ns(current->nsproxy->ipc_ns);
862out:
ae781774 863 return ret;
bc1fc6d8
EB
864out_kfree:
865 kfree(iter);
866 goto out;
867}
868
869static int sysvipc_proc_release(struct inode *inode, struct file *file)
870{
871 struct seq_file *seq = file->private_data;
872 struct ipc_proc_iter *iter = seq->private;
873 put_ipc_ns(iter->ns);
874 return seq_release_private(inode, file);
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875}
876
9a32144e 877static const struct file_operations sysvipc_proc_fops = {
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878 .open = sysvipc_proc_open,
879 .read = seq_read,
880 .llseek = seq_lseek,
bc1fc6d8 881 .release = sysvipc_proc_release,
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882};
883#endif /* CONFIG_PROC_FS */