projects/linux·blob v3.13 · refs

959 lines · 22.5 KiB

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, <[email protected]>
9 * Nov 1999 - ipc helper functions, unified SMP locking
10 * Manfred Spraul <[email protected]>
11 * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
12 * Mingming Cao <[email protected]>
13 * Mar 2006 - support for audit of ipc object properties
14 * Dustin Kirkland <[email protected]>
15 * Jun 2006 - namespaces ssupport
16 * OpenVZ, SWsoft Inc.
17 * Pavel Emelianov <[email protected]>
18 *
19 * General sysv ipc locking scheme:
20 * rcu_read_lock()
21 * obtain the ipc object (kern_ipc_perm) by looking up the id in an idr
22 * tree.
23 * - perform initial checks (capabilities, auditing and permission,
24 * etc).
25 * - perform read-only operations, such as STAT, INFO commands.
26 * acquire the ipc lock (kern_ipc_perm.lock) through
27 * ipc_lock_object()
28 * - perform data updates, such as SET, RMID commands and
29 * mechanism-specific operations (semop/semtimedop,
30 * msgsnd/msgrcv, shmat/shmdt).
31 * drop the ipc lock, through ipc_unlock_object().
32 * rcu_read_unlock()
33 *
34 * The ids->rwsem must be taken when:
35 * - creating, removing and iterating the existing entries in ipc
36 * identifier sets.
37 * - iterating through files under /proc/sysvipc/
38 *
39 * Note that sems have a special fast path that avoids kern_ipc_perm.lock -
40 * see sem_lock().
41 */
42
43#include <linux/mm.h>
44#include <linux/shm.h>
45#include <linux/init.h>
46#include <linux/msg.h>
47#include <linux/vmalloc.h>
48#include <linux/slab.h>
49#include <linux/notifier.h>
50#include <linux/capability.h>
51#include <linux/highuid.h>
52#include <linux/security.h>
53#include <linux/rcupdate.h>
54#include <linux/workqueue.h>
55#include <linux/seq_file.h>
56#include <linux/proc_fs.h>
57#include <linux/audit.h>
58#include <linux/nsproxy.h>
59#include <linux/rwsem.h>
60#include <linux/memory.h>
61#include <linux/ipc_namespace.h>
62
63#include <asm/unistd.h>
64
65#include "util.h"
66
67struct ipc_proc_iface {
68 const char *path;
69 const char *header;
70 int ids;
71 int (*show)(struct seq_file *, void *);
72};
73
74static void ipc_memory_notifier(struct work_struct *work)
75{
76 ipcns_notify(IPCNS_MEMCHANGED);
77}
78
79static int ipc_memory_callback(struct notifier_block *self,
80 unsigned long action, void *arg)
81{
82 static DECLARE_WORK(ipc_memory_wq, ipc_memory_notifier);
83
84 switch (action) {
85 case MEM_ONLINE: /* memory successfully brought online */
86 case MEM_OFFLINE: /* or offline: it's time to recompute msgmni */
87 /*
88 * This is done by invoking the ipcns notifier chain with the
89 * IPC_MEMCHANGED event.
90 * In order not to keep the lock on the hotplug memory chain
91 * for too long, queue a work item that will, when waken up,
92 * activate the ipcns notification chain.
93 */
94 schedule_work(&ipc_memory_wq);
95 break;
96 case MEM_GOING_ONLINE:
97 case MEM_GOING_OFFLINE:
98 case MEM_CANCEL_ONLINE:
99 case MEM_CANCEL_OFFLINE:
100 default:
101 break;
102 }
103
104 return NOTIFY_OK;
105}
106
107static struct notifier_block ipc_memory_nb = {
108 .notifier_call = ipc_memory_callback,
109 .priority = IPC_CALLBACK_PRI,
110};
111
112/**
113 * ipc_init - initialise IPC subsystem
114 *
115 * The various system5 IPC resources (semaphores, messages and shared
116 * memory) are initialised
117 * A callback routine is registered into the memory hotplug notifier
118 * chain: since msgmni scales to lowmem this callback routine will be
119 * called upon successful memory add / remove to recompute msmgni.
120 */
121
122static int __init ipc_init(void)
123{
124 sem_init();
125 msg_init();
126 shm_init();
127 register_hotmemory_notifier(&ipc_memory_nb);
128 register_ipcns_notifier(&init_ipc_ns);
129 return 0;
130}
131__initcall(ipc_init);
132
133/**
134 * ipc_init_ids - initialise IPC identifiers
135 * @ids: Identifier set
136 *
137 * Set up the sequence range to use for the ipc identifier range (limited
138 * below IPCMNI) then initialise the ids idr.
139 */
140
141void ipc_init_ids(struct ipc_ids *ids)
142{
143 init_rwsem(&ids->rwsem);
144
145 ids->in_use = 0;
146 ids->seq = 0;
147 ids->next_id = -1;
148 {
149 int seq_limit = INT_MAX/SEQ_MULTIPLIER;
150 if (seq_limit > USHRT_MAX)
151 ids->seq_max = USHRT_MAX;
152 else
153 ids->seq_max = seq_limit;
154 }
155
156 idr_init(&ids->ipcs_idr);
157}
158
159#ifdef CONFIG_PROC_FS
160static const struct file_operations sysvipc_proc_fops;
161/**
162 * ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface.
163 * @path: Path in procfs
164 * @header: Banner to be printed at the beginning of the file.
165 * @ids: ipc id table to iterate.
166 * @show: show routine.
167 */
168void __init ipc_init_proc_interface(const char *path, const char *header,
169 int ids, int (*show)(struct seq_file *, void *))
170{
171 struct proc_dir_entry *pde;
172 struct ipc_proc_iface *iface;
173
174 iface = kmalloc(sizeof(*iface), GFP_KERNEL);
175 if (!iface)
176 return;
177 iface->path = path;
178 iface->header = header;
179 iface->ids = ids;
180 iface->show = show;
181
182 pde = proc_create_data(path,
183 S_IRUGO, /* world readable */
184 NULL, /* parent dir */
185 &sysvipc_proc_fops,
186 iface);
187 if (!pde) {
188 kfree(iface);
189 }
190}
191#endif
192
193/**
194 * ipc_findkey - find a key in an ipc identifier set
195 * @ids: Identifier set
196 * @key: The key to find
197 *
198 * Requires ipc_ids.rwsem locked.
199 * Returns the LOCKED pointer to the ipc structure if found or NULL
200 * if not.
201 * If key is found ipc points to the owning ipc structure
202 */
203
204static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
205{
206 struct kern_ipc_perm *ipc;
207 int next_id;
208 int total;
209
210 for (total = 0, next_id = 0; total < ids->in_use; next_id++) {
211 ipc = idr_find(&ids->ipcs_idr, next_id);
212
213 if (ipc == NULL)
214 continue;
215
216 if (ipc->key != key) {
217 total++;
218 continue;
219 }
220
221 rcu_read_lock();
222 ipc_lock_object(ipc);
223 return ipc;
224 }
225
226 return NULL;
227}
228
229/**
230 * ipc_get_maxid - get the last assigned id
231 * @ids: IPC identifier set
232 *
233 * Called with ipc_ids.rwsem held.
234 */
235
236int ipc_get_maxid(struct ipc_ids *ids)
237{
238 struct kern_ipc_perm *ipc;
239 int max_id = -1;
240 int total, id;
241
242 if (ids->in_use == 0)
243 return -1;
244
245 if (ids->in_use == IPCMNI)
246 return IPCMNI - 1;
247
248 /* Look for the last assigned id */
249 total = 0;
250 for (id = 0; id < IPCMNI && total < ids->in_use; id++) {
251 ipc = idr_find(&ids->ipcs_idr, id);
252 if (ipc != NULL) {
253 max_id = id;
254 total++;
255 }
256 }
257 return max_id;
258}
259
260/**
261 * ipc_addid - add an IPC identifier
262 * @ids: IPC identifier set
263 * @new: new IPC permission set
264 * @size: limit for the number of used ids
265 *
266 * Add an entry 'new' to the IPC ids idr. The permissions object is
267 * initialised and the first free entry is set up and the id assigned
268 * is returned. The 'new' entry is returned in a locked state on success.
269 * On failure the entry is not locked and a negative err-code is returned.
270 *
271 * Called with writer ipc_ids.rwsem held.
272 */
273int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size)
274{
275 kuid_t euid;
276 kgid_t egid;
277 int id;
278 int next_id = ids->next_id;
279
280 if (size > IPCMNI)
281 size = IPCMNI;
282
283 if (ids->in_use >= size)
284 return -ENOSPC;
285
286 idr_preload(GFP_KERNEL);
287
288 spin_lock_init(&new->lock);
289 new->deleted = 0;
290 rcu_read_lock();
291 spin_lock(&new->lock);
292
293 id = idr_alloc(&ids->ipcs_idr, new,
294 (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0,
295 GFP_NOWAIT);
296 idr_preload_end();
297 if (id < 0) {
298 spin_unlock(&new->lock);
299 rcu_read_unlock();
300 return id;
301 }
302
303 ids->in_use++;
304
305 current_euid_egid(&euid, &egid);
306 new->cuid = new->uid = euid;
307 new->gid = new->cgid = egid;
308
309 if (next_id < 0) {
310 new->seq = ids->seq++;
311 if (ids->seq > ids->seq_max)
312 ids->seq = 0;
313 } else {
314 new->seq = ipcid_to_seqx(next_id);
315 ids->next_id = -1;
316 }
317
318 new->id = ipc_buildid(id, new->seq);
319 return id;
320}
321
322/**
323 * ipcget_new - create a new ipc object
324 * @ns: namespace
325 * @ids: IPC identifer set
326 * @ops: the actual creation routine to call
327 * @params: its parameters
328 *
329 * This routine is called by sys_msgget, sys_semget() and sys_shmget()
330 * when the key is IPC_PRIVATE.
331 */
332static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
333 struct ipc_ops *ops, struct ipc_params *params)
334{
335 int err;
336
337 down_write(&ids->rwsem);
338 err = ops->getnew(ns, params);
339 up_write(&ids->rwsem);
340 return err;
341}
342
343/**
344 * ipc_check_perms - check security and permissions for an IPC
345 * @ns: IPC namespace
346 * @ipcp: ipc permission set
347 * @ops: the actual security routine to call
348 * @params: its parameters
349 *
350 * This routine is called by sys_msgget(), sys_semget() and sys_shmget()
351 * when the key is not IPC_PRIVATE and that key already exists in the
352 * ids IDR.
353 *
354 * On success, the IPC id is returned.
355 *
356 * It is called with ipc_ids.rwsem and ipcp->lock held.
357 */
358static int ipc_check_perms(struct ipc_namespace *ns,
359 struct kern_ipc_perm *ipcp,
360 struct ipc_ops *ops,
361 struct ipc_params *params)
362{
363 int err;
364
365 if (ipcperms(ns, ipcp, params->flg))
366 err = -EACCES;
367 else {
368 err = ops->associate(ipcp, params->flg);
369 if (!err)
370 err = ipcp->id;
371 }
372
373 return err;
374}
375
376/**
377 * ipcget_public - get an ipc object or create a new one
378 * @ns: namespace
379 * @ids: IPC identifer set
380 * @ops: the actual creation routine to call
381 * @params: its parameters
382 *
383 * This routine is called by sys_msgget, sys_semget() and sys_shmget()
384 * when the key is not IPC_PRIVATE.
385 * It adds a new entry if the key is not found and does some permission
386 * / security checkings if the key is found.
387 *
388 * On success, the ipc id is returned.
389 */
390static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
391 struct ipc_ops *ops, struct ipc_params *params)
392{
393 struct kern_ipc_perm *ipcp;
394 int flg = params->flg;
395 int err;
396
397 /*
398 * Take the lock as a writer since we are potentially going to add
399 * a new entry + read locks are not "upgradable"
400 */
401 down_write(&ids->rwsem);
402 ipcp = ipc_findkey(ids, params->key);
403 if (ipcp == NULL) {
404 /* key not used */
405 if (!(flg & IPC_CREAT))
406 err = -ENOENT;
407 else
408 err = ops->getnew(ns, params);
409 } else {
410 /* ipc object has been locked by ipc_findkey() */
411
412 if (flg & IPC_CREAT && flg & IPC_EXCL)
413 err = -EEXIST;
414 else {
415 err = 0;
416 if (ops->more_checks)
417 err = ops->more_checks(ipcp, params);
418 if (!err)
419 /*
420 * ipc_check_perms returns the IPC id on
421 * success
422 */
423 err = ipc_check_perms(ns, ipcp, ops, params);
424 }
425 ipc_unlock(ipcp);
426 }
427 up_write(&ids->rwsem);
428
429 return err;
430}
431
432
433/**
434 * ipc_rmid - remove an IPC identifier
435 * @ids: IPC identifier set
436 * @ipcp: ipc perm structure containing the identifier to remove
437 *
438 * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
439 * before this function is called, and remain locked on the exit.
440 */
441
442void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
443{
444 int lid = ipcid_to_idx(ipcp->id);
445
446 idr_remove(&ids->ipcs_idr, lid);
447
448 ids->in_use--;
449
450 ipcp->deleted = 1;
451
452 return;
453}
454
455/**
456 * ipc_alloc - allocate ipc space
457 * @size: size desired
458 *
459 * Allocate memory from the appropriate pools and return a pointer to it.
460 * NULL is returned if the allocation fails
461 */
462
463void *ipc_alloc(int size)
464{
465 void *out;
466 if(size > PAGE_SIZE)
467 out = vmalloc(size);
468 else
469 out = kmalloc(size, GFP_KERNEL);
470 return out;
471}
472
473/**
474 * ipc_free - free ipc space
475 * @ptr: pointer returned by ipc_alloc
476 * @size: size of block
477 *
478 * Free a block created with ipc_alloc(). The caller must know the size
479 * used in the allocation call.
480 */
481
482void ipc_free(void* ptr, int size)
483{
484 if(size > PAGE_SIZE)
485 vfree(ptr);
486 else
487 kfree(ptr);
488}
489
490/**
491 * ipc_rcu_alloc - allocate ipc and rcu space
492 * @size: size desired
493 *
494 * Allocate memory for the rcu header structure + the object.
495 * Returns the pointer to the object or NULL upon failure.
496 */
497void *ipc_rcu_alloc(int size)
498{
499 /*
500 * We prepend the allocation with the rcu struct
501 */
502 struct ipc_rcu *out = ipc_alloc(sizeof(struct ipc_rcu) + size);
503 if (unlikely(!out))
504 return NULL;
505 atomic_set(&out->refcount, 1);
506 return out + 1;
507}
508
509int ipc_rcu_getref(void *ptr)
510{
511 struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1;
512
513 return atomic_inc_not_zero(&p->refcount);
514}
515
516void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head))
517{
518 struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1;
519
520 if (!atomic_dec_and_test(&p->refcount))
521 return;
522
523 call_rcu(&p->rcu, func);
524}
525
526void ipc_rcu_free(struct rcu_head *head)
527{
528 struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
529
530 if (is_vmalloc_addr(p))
531 vfree(p);
532 else
533 kfree(p);
534}
535
536/**
537 * ipcperms - check IPC permissions
538 * @ns: IPC namespace
539 * @ipcp: IPC permission set
540 * @flag: desired permission set.
541 *
542 * Check user, group, other permissions for access
543 * to ipc resources. return 0 if allowed
544 *
545 * @flag will most probably be 0 or S_...UGO from <linux/stat.h>
546 */
547
548int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag)
549{
550 kuid_t euid = current_euid();
551 int requested_mode, granted_mode;
552
553 audit_ipc_obj(ipcp);
554 requested_mode = (flag >> 6) | (flag >> 3) | flag;
555 granted_mode = ipcp->mode;
556 if (uid_eq(euid, ipcp->cuid) ||
557 uid_eq(euid, ipcp->uid))
558 granted_mode >>= 6;
559 else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
560 granted_mode >>= 3;
561 /* is there some bit set in requested_mode but not in granted_mode? */
562 if ((requested_mode & ~granted_mode & 0007) &&
563 !ns_capable(ns->user_ns, CAP_IPC_OWNER))
564 return -1;
565
566 return security_ipc_permission(ipcp, flag);
567}
568
569/*
570 * Functions to convert between the kern_ipc_perm structure and the
571 * old/new ipc_perm structures
572 */
573
574/**
575 * kernel_to_ipc64_perm - convert kernel ipc permissions to user
576 * @in: kernel permissions
577 * @out: new style IPC permissions
578 *
579 * Turn the kernel object @in into a set of permissions descriptions
580 * for returning to userspace (@out).
581 */
582
583
584void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out)
585{
586 out->key = in->key;
587 out->uid = from_kuid_munged(current_user_ns(), in->uid);
588 out->gid = from_kgid_munged(current_user_ns(), in->gid);
589 out->cuid = from_kuid_munged(current_user_ns(), in->cuid);
590 out->cgid = from_kgid_munged(current_user_ns(), in->cgid);
591 out->mode = in->mode;
592 out->seq = in->seq;
593}
594
595/**
596 * ipc64_perm_to_ipc_perm - convert new ipc permissions to old
597 * @in: new style IPC permissions
598 * @out: old style IPC permissions
599 *
600 * Turn the new style permissions object @in into a compatibility
601 * object and store it into the @out pointer.
602 */
603
604void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out)
605{
606 out->key = in->key;
607 SET_UID(out->uid, in->uid);
608 SET_GID(out->gid, in->gid);
609 SET_UID(out->cuid, in->cuid);
610 SET_GID(out->cgid, in->cgid);
611 out->mode = in->mode;
612 out->seq = in->seq;
613}
614
615/**
616 * ipc_obtain_object
617 * @ids: ipc identifier set
618 * @id: ipc id to look for
619 *
620 * Look for an id in the ipc ids idr and return associated ipc object.
621 *
622 * Call inside the RCU critical section.
623 * The ipc object is *not* locked on exit.
624 */
625struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id)
626{
627 struct kern_ipc_perm *out;
628 int lid = ipcid_to_idx(id);
629
630 out = idr_find(&ids->ipcs_idr, lid);
631 if (!out)
632 return ERR_PTR(-EINVAL);
633
634 return out;
635}
636
637/**
638 * ipc_lock - Lock an ipc structure without rwsem held
639 * @ids: IPC identifier set
640 * @id: ipc id to look for
641 *
642 * Look for an id in the ipc ids idr and lock the associated ipc object.
643 *
644 * The ipc object is locked on successful exit.
645 */
646struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
647{
648 struct kern_ipc_perm *out;
649
650 rcu_read_lock();
651 out = ipc_obtain_object(ids, id);
652 if (IS_ERR(out))
653 goto err1;
654
655 spin_lock(&out->lock);
656
657 /* ipc_rmid() may have already freed the ID while ipc_lock
658 * was spinning: here verify that the structure is still valid
659 */
660 if (!out->deleted)
661 return out;
662
663 spin_unlock(&out->lock);
664 out = ERR_PTR(-EINVAL);
665err1:
666 rcu_read_unlock();
667 return out;
668}
669
670/**
671 * ipc_obtain_object_check
672 * @ids: ipc identifier set
673 * @id: ipc id to look for
674 *
675 * Similar to ipc_obtain_object() but also checks
676 * the ipc object reference counter.
677 *
678 * Call inside the RCU critical section.
679 * The ipc object is *not* locked on exit.
680 */
681struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id)
682{
683 struct kern_ipc_perm *out = ipc_obtain_object(ids, id);
684
685 if (IS_ERR(out))
686 goto out;
687
688 if (ipc_checkid(out, id))
689 return ERR_PTR(-EIDRM);
690out:
691 return out;
692}
693
694/**
695 * ipcget - Common sys_*get() code
696 * @ns : namsepace
697 * @ids : IPC identifier set
698 * @ops : operations to be called on ipc object creation, permission checks
699 * and further checks
700 * @params : the parameters needed by the previous operations.
701 *
702 * Common routine called by sys_msgget(), sys_semget() and sys_shmget().
703 */
704int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
705 struct ipc_ops *ops, struct ipc_params *params)
706{
707 if (params->key == IPC_PRIVATE)
708 return ipcget_new(ns, ids, ops, params);
709 else
710 return ipcget_public(ns, ids, ops, params);
711}
712
713/**
714 * ipc_update_perm - update the permissions of an IPC.
715 * @in: the permission given as input.
716 * @out: the permission of the ipc to set.
717 */
718int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
719{
720 kuid_t uid = make_kuid(current_user_ns(), in->uid);
721 kgid_t gid = make_kgid(current_user_ns(), in->gid);
722 if (!uid_valid(uid) || !gid_valid(gid))
723 return -EINVAL;
724
725 out->uid = uid;
726 out->gid = gid;
727 out->mode = (out->mode & ~S_IRWXUGO)
728 | (in->mode & S_IRWXUGO);
729
730 return 0;
731}
732
733/**
734 * ipcctl_pre_down_nolock - retrieve an ipc and check permissions for some IPC_XXX cmd
735 * @ns: the ipc namespace
736 * @ids: the table of ids where to look for the ipc
737 * @id: the id of the ipc to retrieve
738 * @cmd: the cmd to check
739 * @perm: the permission to set
740 * @extra_perm: one extra permission parameter used by msq
741 *
742 * This function does some common audit and permissions check for some IPC_XXX
743 * cmd and is called from semctl_down, shmctl_down and msgctl_down.
744 * It must be called without any lock held and
745 * - retrieves the ipc with the given id in the given table.
746 * - performs some audit and permission check, depending on the given cmd
747 * - returns a pointer to the ipc object or otherwise, the corresponding error.
748 *
749 * Call holding the both the rwsem and the rcu read lock.
750 */
751struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
752 struct ipc_ids *ids, int id, int cmd,
753 struct ipc64_perm *perm, int extra_perm)
754{
755 kuid_t euid;
756 int err = -EPERM;
757 struct kern_ipc_perm *ipcp;
758
759 ipcp = ipc_obtain_object_check(ids, id);
760 if (IS_ERR(ipcp)) {
761 err = PTR_ERR(ipcp);
762 goto err;
763 }
764
765 audit_ipc_obj(ipcp);
766 if (cmd == IPC_SET)
767 audit_ipc_set_perm(extra_perm, perm->uid,
768 perm->gid, perm->mode);
769
770 euid = current_euid();
771 if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) ||
772 ns_capable(ns->user_ns, CAP_SYS_ADMIN))
773 return ipcp; /* successful lookup */
774err:
775 return ERR_PTR(err);
776}
777
778#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
779
780
781/**
782 * ipc_parse_version - IPC call version
783 * @cmd: pointer to command
784 *
785 * Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
786 * The @cmd value is turned from an encoding command and version into
787 * just the command code.
788 */
789
790int ipc_parse_version (int *cmd)
791{
792 if (*cmd & IPC_64) {
793 *cmd ^= IPC_64;
794 return IPC_64;
795 } else {
796 return IPC_OLD;
797 }
798}
799
800#endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */
801
802#ifdef CONFIG_PROC_FS
803struct ipc_proc_iter {
804 struct ipc_namespace *ns;
805 struct ipc_proc_iface *iface;
806};
807
808/*
809 * This routine locks the ipc structure found at least at position pos.
810 */
811static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
812 loff_t *new_pos)
813{
814 struct kern_ipc_perm *ipc;
815 int total, id;
816
817 total = 0;
818 for (id = 0; id < pos && total < ids->in_use; id++) {
819 ipc = idr_find(&ids->ipcs_idr, id);
820 if (ipc != NULL)
821 total++;
822 }
823
824 if (total >= ids->in_use)
825 return NULL;
826
827 for ( ; pos < IPCMNI; pos++) {
828 ipc = idr_find(&ids->ipcs_idr, pos);
829 if (ipc != NULL) {
830 *new_pos = pos + 1;
831 rcu_read_lock();
832 ipc_lock_object(ipc);
833 return ipc;
834 }
835 }
836
837 /* Out of range - return NULL to terminate iteration */
838 return NULL;
839}
840
841static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
842{
843 struct ipc_proc_iter *iter = s->private;
844 struct ipc_proc_iface *iface = iter->iface;
845 struct kern_ipc_perm *ipc = it;
846
847 /* If we had an ipc id locked before, unlock it */
848 if (ipc && ipc != SEQ_START_TOKEN)
849 ipc_unlock(ipc);
850
851 return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos);
852}
853
854/*
855 * File positions: pos 0 -> header, pos n -> ipc id = n - 1.
856 * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START.
857 */
858static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
859{
860 struct ipc_proc_iter *iter = s->private;
861 struct ipc_proc_iface *iface = iter->iface;
862 struct ipc_ids *ids;
863
864 ids = &iter->ns->ids[iface->ids];
865
866 /*
867 * Take the lock - this will be released by the corresponding
868 * call to stop().
869 */
870 down_read(&ids->rwsem);
871
872 /* pos < 0 is invalid */
873 if (*pos < 0)
874 return NULL;
875
876 /* pos == 0 means header */
877 if (*pos == 0)
878 return SEQ_START_TOKEN;
879
880 /* Find the (pos-1)th ipc */
881 return sysvipc_find_ipc(ids, *pos - 1, pos);
882}
883
884static void sysvipc_proc_stop(struct seq_file *s, void *it)
885{
886 struct kern_ipc_perm *ipc = it;
887 struct ipc_proc_iter *iter = s->private;
888 struct ipc_proc_iface *iface = iter->iface;
889 struct ipc_ids *ids;
890
891 /* If we had a locked structure, release it */
892 if (ipc && ipc != SEQ_START_TOKEN)
893 ipc_unlock(ipc);
894
895 ids = &iter->ns->ids[iface->ids];
896 /* Release the lock we took in start() */
897 up_read(&ids->rwsem);
898}
899
900static int sysvipc_proc_show(struct seq_file *s, void *it)
901{
902 struct ipc_proc_iter *iter = s->private;
903 struct ipc_proc_iface *iface = iter->iface;
904
905 if (it == SEQ_START_TOKEN)
906 return seq_puts(s, iface->header);
907
908 return iface->show(s, it);
909}
910
911static const struct seq_operations sysvipc_proc_seqops = {
912 .start = sysvipc_proc_start,
913 .stop = sysvipc_proc_stop,
914 .next = sysvipc_proc_next,
915 .show = sysvipc_proc_show,
916};
917
918static int sysvipc_proc_open(struct inode *inode, struct file *file)
919{
920 int ret;
921 struct seq_file *seq;
922 struct ipc_proc_iter *iter;
923
924 ret = -ENOMEM;
925 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
926 if (!iter)
927 goto out;
928
929 ret = seq_open(file, &sysvipc_proc_seqops);
930 if (ret)
931 goto out_kfree;
932
933 seq = file->private_data;
934 seq->private = iter;
935
936 iter->iface = PDE_DATA(inode);
937 iter->ns = get_ipc_ns(current->nsproxy->ipc_ns);
938out:
939 return ret;
940out_kfree:
941 kfree(iter);
942 goto out;
943}
944
945static int sysvipc_proc_release(struct inode *inode, struct file *file)
946{
947 struct seq_file *seq = file->private_data;
948 struct ipc_proc_iter *iter = seq->private;
949 put_ipc_ns(iter->ns);
950 return seq_release_private(inode, file);
951}
952
953static const struct file_operations sysvipc_proc_fops = {
954 .open = sysvipc_proc_open,
955 .read = seq_read,
956 .llseek = seq_lseek,
957 .release = sysvipc_proc_release,
958};
959#endif /* CONFIG_PROC_FS */