Commit | Line | Data |
---|---|---|
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 |
40 | struct 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 |
47 | struct ipc_namespace init_ipc_ns = { |
48 | .kref = { | |
49 | .refcount = ATOMIC_INIT(2), | |
50 | }, | |
51 | }; | |
52 | ||
73ea4130 KK |
53 | static 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 | ||
76 | err_shm: | |
77 | msg_exit_ns(ns); | |
78 | err_msg: | |
79 | sem_exit_ns(ns); | |
80 | err_sem: | |
81 | kfree(ns); | |
82 | err_mem: | |
83 | return ERR_PTR(err); | |
84 | } | |
85 | ||
e3222c4e | 86 | struct 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 | ||
102 | void 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 | ||
120 | static 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 | |
132 | * @size: Number of identifiers | |
133 | * | |
134 | * Given a size for the ipc identifier range (limited below IPCMNI) | |
135 | * set up the sequence range to use then allocate and initialise the | |
136 | * array itself. | |
137 | */ | |
138 | ||
7d69a1f4 | 139 | void ipc_init_ids(struct ipc_ids* ids, int size) |
1da177e4 LT |
140 | { |
141 | int i; | |
5f921ae9 IM |
142 | |
143 | mutex_init(&ids->mutex); | |
1da177e4 LT |
144 | |
145 | if(size > IPCMNI) | |
146 | size = IPCMNI; | |
147 | ids->in_use = 0; | |
148 | ids->max_id = -1; | |
149 | ids->seq = 0; | |
150 | { | |
151 | int seq_limit = INT_MAX/SEQ_MULTIPLIER; | |
152 | if(seq_limit > USHRT_MAX) | |
153 | ids->seq_max = USHRT_MAX; | |
154 | else | |
155 | ids->seq_max = seq_limit; | |
156 | } | |
157 | ||
158 | ids->entries = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*size + | |
159 | sizeof(struct ipc_id_ary)); | |
160 | ||
161 | if(ids->entries == NULL) { | |
162 | printk(KERN_ERR "ipc_init_ids() failed, ipc service disabled.\n"); | |
163 | size = 0; | |
164 | ids->entries = &ids->nullentry; | |
165 | } | |
166 | ids->entries->size = size; | |
167 | for(i=0;i<size;i++) | |
168 | ids->entries->p[i] = NULL; | |
169 | } | |
170 | ||
ae781774 | 171 | #ifdef CONFIG_PROC_FS |
9a32144e | 172 | static const struct file_operations sysvipc_proc_fops; |
ae781774 | 173 | /** |
72fd4a35 | 174 | * ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface. |
ae781774 MW |
175 | * @path: Path in procfs |
176 | * @header: Banner to be printed at the beginning of the file. | |
177 | * @ids: ipc id table to iterate. | |
178 | * @show: show routine. | |
179 | */ | |
180 | void __init ipc_init_proc_interface(const char *path, const char *header, | |
73ea4130 | 181 | int ids, int (*show)(struct seq_file *, void *)) |
ae781774 MW |
182 | { |
183 | struct proc_dir_entry *pde; | |
184 | struct ipc_proc_iface *iface; | |
185 | ||
186 | iface = kmalloc(sizeof(*iface), GFP_KERNEL); | |
187 | if (!iface) | |
188 | return; | |
189 | iface->path = path; | |
190 | iface->header = header; | |
191 | iface->ids = ids; | |
192 | iface->show = show; | |
193 | ||
194 | pde = create_proc_entry(path, | |
195 | S_IRUGO, /* world readable */ | |
196 | NULL /* parent dir */); | |
197 | if (pde) { | |
198 | pde->data = iface; | |
199 | pde->proc_fops = &sysvipc_proc_fops; | |
200 | } else { | |
201 | kfree(iface); | |
202 | } | |
203 | } | |
204 | #endif | |
205 | ||
1da177e4 LT |
206 | /** |
207 | * ipc_findkey - find a key in an ipc identifier set | |
208 | * @ids: Identifier set | |
209 | * @key: The key to find | |
210 | * | |
5f921ae9 | 211 | * Requires ipc_ids.mutex locked. |
1da177e4 LT |
212 | * Returns the identifier if found or -1 if not. |
213 | */ | |
214 | ||
215 | int ipc_findkey(struct ipc_ids* ids, key_t key) | |
216 | { | |
217 | int id; | |
218 | struct kern_ipc_perm* p; | |
219 | int max_id = ids->max_id; | |
220 | ||
221 | /* | |
222 | * rcu_dereference() is not needed here | |
5f921ae9 | 223 | * since ipc_ids.mutex is held |
1da177e4 LT |
224 | */ |
225 | for (id = 0; id <= max_id; id++) { | |
226 | p = ids->entries->p[id]; | |
227 | if(p==NULL) | |
228 | continue; | |
229 | if (key == p->key) | |
230 | return id; | |
231 | } | |
232 | return -1; | |
233 | } | |
234 | ||
235 | /* | |
5f921ae9 | 236 | * Requires ipc_ids.mutex locked |
1da177e4 LT |
237 | */ |
238 | static int grow_ary(struct ipc_ids* ids, int newsize) | |
239 | { | |
240 | struct ipc_id_ary* new; | |
241 | struct ipc_id_ary* old; | |
242 | int i; | |
243 | int size = ids->entries->size; | |
244 | ||
245 | if(newsize > IPCMNI) | |
246 | newsize = IPCMNI; | |
247 | if(newsize <= size) | |
248 | return newsize; | |
249 | ||
250 | new = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*newsize + | |
251 | sizeof(struct ipc_id_ary)); | |
252 | if(new == NULL) | |
253 | return size; | |
254 | new->size = newsize; | |
a9a5cd5d | 255 | memcpy(new->p, ids->entries->p, sizeof(struct kern_ipc_perm *)*size); |
1da177e4 LT |
256 | for(i=size;i<newsize;i++) { |
257 | new->p[i] = NULL; | |
258 | } | |
259 | old = ids->entries; | |
260 | ||
261 | /* | |
262 | * Use rcu_assign_pointer() to make sure the memcpyed contents | |
263 | * of the new array are visible before the new array becomes visible. | |
264 | */ | |
265 | rcu_assign_pointer(ids->entries, new); | |
266 | ||
c7e12b83 | 267 | __ipc_fini_ids(ids, old); |
1da177e4 LT |
268 | return newsize; |
269 | } | |
270 | ||
271 | /** | |
272 | * ipc_addid - add an IPC identifier | |
273 | * @ids: IPC identifier set | |
274 | * @new: new IPC permission set | |
275 | * @size: new size limit for the id array | |
276 | * | |
277 | * Add an entry 'new' to the IPC arrays. The permissions object is | |
278 | * initialised and the first free entry is set up and the id assigned | |
279 | * is returned. The list is returned in a locked state on success. | |
280 | * On failure the list is not locked and -1 is returned. | |
281 | * | |
5f921ae9 | 282 | * Called with ipc_ids.mutex held. |
1da177e4 LT |
283 | */ |
284 | ||
285 | int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) | |
286 | { | |
287 | int id; | |
288 | ||
289 | size = grow_ary(ids,size); | |
290 | ||
291 | /* | |
292 | * rcu_dereference()() is not needed here since | |
5f921ae9 | 293 | * ipc_ids.mutex is held |
1da177e4 LT |
294 | */ |
295 | for (id = 0; id < size; id++) { | |
296 | if(ids->entries->p[id] == NULL) | |
297 | goto found; | |
298 | } | |
299 | return -1; | |
300 | found: | |
301 | ids->in_use++; | |
302 | if (id > ids->max_id) | |
303 | ids->max_id = id; | |
304 | ||
305 | new->cuid = new->uid = current->euid; | |
306 | new->gid = new->cgid = current->egid; | |
307 | ||
308 | new->seq = ids->seq++; | |
309 | if(ids->seq > ids->seq_max) | |
310 | ids->seq = 0; | |
311 | ||
312 | spin_lock_init(&new->lock); | |
313 | new->deleted = 0; | |
314 | rcu_read_lock(); | |
315 | spin_lock(&new->lock); | |
316 | ids->entries->p[id] = new; | |
317 | return id; | |
318 | } | |
319 | ||
320 | /** | |
321 | * ipc_rmid - remove an IPC identifier | |
322 | * @ids: identifier set | |
323 | * @id: Identifier to remove | |
324 | * | |
325 | * The identifier must be valid, and in use. The kernel will panic if | |
326 | * fed an invalid identifier. The entry is removed and internal | |
327 | * variables recomputed. The object associated with the identifier | |
328 | * is returned. | |
5f921ae9 | 329 | * ipc_ids.mutex and the spinlock for this ID is hold before this function |
1da177e4 LT |
330 | * is called, and remain locked on the exit. |
331 | */ | |
332 | ||
333 | struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id) | |
334 | { | |
335 | struct kern_ipc_perm* p; | |
336 | int lid = id % SEQ_MULTIPLIER; | |
9bc98fc6 | 337 | BUG_ON(lid >= ids->entries->size); |
1da177e4 LT |
338 | |
339 | /* | |
340 | * do not need a rcu_dereference()() here to force ordering | |
5f921ae9 | 341 | * on Alpha, since the ipc_ids.mutex is held. |
1da177e4 LT |
342 | */ |
343 | p = ids->entries->p[lid]; | |
344 | ids->entries->p[lid] = NULL; | |
9bc98fc6 | 345 | BUG_ON(p==NULL); |
1da177e4 LT |
346 | ids->in_use--; |
347 | ||
348 | if (lid == ids->max_id) { | |
349 | do { | |
350 | lid--; | |
351 | if(lid == -1) | |
352 | break; | |
353 | } while (ids->entries->p[lid] == NULL); | |
354 | ids->max_id = lid; | |
355 | } | |
356 | p->deleted = 1; | |
357 | return p; | |
358 | } | |
359 | ||
360 | /** | |
361 | * ipc_alloc - allocate ipc space | |
362 | * @size: size desired | |
363 | * | |
364 | * Allocate memory from the appropriate pools and return a pointer to it. | |
365 | * NULL is returned if the allocation fails | |
366 | */ | |
367 | ||
368 | void* ipc_alloc(int size) | |
369 | { | |
370 | void* out; | |
371 | if(size > PAGE_SIZE) | |
372 | out = vmalloc(size); | |
373 | else | |
374 | out = kmalloc(size, GFP_KERNEL); | |
375 | return out; | |
376 | } | |
377 | ||
378 | /** | |
379 | * ipc_free - free ipc space | |
380 | * @ptr: pointer returned by ipc_alloc | |
381 | * @size: size of block | |
382 | * | |
72fd4a35 | 383 | * Free a block created with ipc_alloc(). The caller must know the size |
1da177e4 LT |
384 | * used in the allocation call. |
385 | */ | |
386 | ||
387 | void ipc_free(void* ptr, int size) | |
388 | { | |
389 | if(size > PAGE_SIZE) | |
390 | vfree(ptr); | |
391 | else | |
392 | kfree(ptr); | |
393 | } | |
394 | ||
395 | /* | |
396 | * rcu allocations: | |
397 | * There are three headers that are prepended to the actual allocation: | |
398 | * - during use: ipc_rcu_hdr. | |
399 | * - during the rcu grace period: ipc_rcu_grace. | |
400 | * - [only if vmalloc]: ipc_rcu_sched. | |
401 | * Their lifetime doesn't overlap, thus the headers share the same memory. | |
402 | * Unlike a normal union, they are right-aligned, thus some container_of | |
403 | * forward/backward casting is necessary: | |
404 | */ | |
405 | struct ipc_rcu_hdr | |
406 | { | |
407 | int refcount; | |
408 | int is_vmalloc; | |
409 | void *data[0]; | |
410 | }; | |
411 | ||
412 | ||
413 | struct ipc_rcu_grace | |
414 | { | |
415 | struct rcu_head rcu; | |
416 | /* "void *" makes sure alignment of following data is sane. */ | |
417 | void *data[0]; | |
418 | }; | |
419 | ||
420 | struct ipc_rcu_sched | |
421 | { | |
422 | struct work_struct work; | |
423 | /* "void *" makes sure alignment of following data is sane. */ | |
424 | void *data[0]; | |
425 | }; | |
426 | ||
427 | #define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \ | |
428 | sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr)) | |
429 | #define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \ | |
430 | sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC) | |
431 | ||
432 | static inline int rcu_use_vmalloc(int size) | |
433 | { | |
434 | /* Too big for a single page? */ | |
435 | if (HDRLEN_KMALLOC + size > PAGE_SIZE) | |
436 | return 1; | |
437 | return 0; | |
438 | } | |
439 | ||
440 | /** | |
441 | * ipc_rcu_alloc - allocate ipc and rcu space | |
442 | * @size: size desired | |
443 | * | |
444 | * Allocate memory for the rcu header structure + the object. | |
445 | * Returns the pointer to the object. | |
446 | * NULL is returned if the allocation fails. | |
447 | */ | |
448 | ||
449 | void* ipc_rcu_alloc(int size) | |
450 | { | |
451 | void* out; | |
452 | /* | |
453 | * We prepend the allocation with the rcu struct, and | |
454 | * workqueue if necessary (for vmalloc). | |
455 | */ | |
456 | if (rcu_use_vmalloc(size)) { | |
457 | out = vmalloc(HDRLEN_VMALLOC + size); | |
458 | if (out) { | |
459 | out += HDRLEN_VMALLOC; | |
460 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1; | |
461 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
462 | } | |
463 | } else { | |
464 | out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL); | |
465 | if (out) { | |
466 | out += HDRLEN_KMALLOC; | |
467 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0; | |
468 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
469 | } | |
470 | } | |
471 | ||
472 | return out; | |
473 | } | |
474 | ||
475 | void ipc_rcu_getref(void *ptr) | |
476 | { | |
477 | container_of(ptr, struct ipc_rcu_hdr, data)->refcount++; | |
478 | } | |
479 | ||
65f27f38 DH |
480 | static void ipc_do_vfree(struct work_struct *work) |
481 | { | |
482 | vfree(container_of(work, struct ipc_rcu_sched, work)); | |
483 | } | |
484 | ||
1da177e4 | 485 | /** |
1e5d5331 RD |
486 | * ipc_schedule_free - free ipc + rcu space |
487 | * @head: RCU callback structure for queued work | |
1da177e4 LT |
488 | * |
489 | * Since RCU callback function is called in bh, | |
72fd4a35 | 490 | * we need to defer the vfree to schedule_work(). |
1da177e4 LT |
491 | */ |
492 | static void ipc_schedule_free(struct rcu_head *head) | |
493 | { | |
494 | struct ipc_rcu_grace *grace = | |
495 | container_of(head, struct ipc_rcu_grace, rcu); | |
496 | struct ipc_rcu_sched *sched = | |
497 | container_of(&(grace->data[0]), struct ipc_rcu_sched, data[0]); | |
498 | ||
65f27f38 | 499 | INIT_WORK(&sched->work, ipc_do_vfree); |
1da177e4 LT |
500 | schedule_work(&sched->work); |
501 | } | |
502 | ||
503 | /** | |
1e5d5331 RD |
504 | * ipc_immediate_free - free ipc + rcu space |
505 | * @head: RCU callback structure that contains pointer to be freed | |
1da177e4 | 506 | * |
72fd4a35 | 507 | * Free from the RCU callback context. |
1da177e4 LT |
508 | */ |
509 | static void ipc_immediate_free(struct rcu_head *head) | |
510 | { | |
511 | struct ipc_rcu_grace *free = | |
512 | container_of(head, struct ipc_rcu_grace, rcu); | |
513 | kfree(free); | |
514 | } | |
515 | ||
516 | void ipc_rcu_putref(void *ptr) | |
517 | { | |
518 | if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0) | |
519 | return; | |
520 | ||
521 | if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) { | |
522 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
523 | ipc_schedule_free); | |
524 | } else { | |
525 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
526 | ipc_immediate_free); | |
527 | } | |
528 | } | |
529 | ||
530 | /** | |
531 | * ipcperms - check IPC permissions | |
532 | * @ipcp: IPC permission set | |
533 | * @flag: desired permission set. | |
534 | * | |
535 | * Check user, group, other permissions for access | |
536 | * to ipc resources. return 0 if allowed | |
537 | */ | |
538 | ||
539 | int ipcperms (struct kern_ipc_perm *ipcp, short flag) | |
540 | { /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */ | |
073115d6 | 541 | int requested_mode, granted_mode, err; |
1da177e4 | 542 | |
073115d6 SG |
543 | if (unlikely((err = audit_ipc_obj(ipcp)))) |
544 | return err; | |
1da177e4 LT |
545 | requested_mode = (flag >> 6) | (flag >> 3) | flag; |
546 | granted_mode = ipcp->mode; | |
547 | if (current->euid == ipcp->cuid || current->euid == ipcp->uid) | |
548 | granted_mode >>= 6; | |
549 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) | |
550 | granted_mode >>= 3; | |
551 | /* is there some bit set in requested_mode but not in granted_mode? */ | |
552 | if ((requested_mode & ~granted_mode & 0007) && | |
553 | !capable(CAP_IPC_OWNER)) | |
554 | return -1; | |
555 | ||
556 | return security_ipc_permission(ipcp, flag); | |
557 | } | |
558 | ||
559 | /* | |
560 | * Functions to convert between the kern_ipc_perm structure and the | |
561 | * old/new ipc_perm structures | |
562 | */ | |
563 | ||
564 | /** | |
565 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user | |
566 | * @in: kernel permissions | |
567 | * @out: new style IPC permissions | |
568 | * | |
72fd4a35 RD |
569 | * Turn the kernel object @in into a set of permissions descriptions |
570 | * for returning to userspace (@out). | |
1da177e4 LT |
571 | */ |
572 | ||
573 | ||
574 | void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out) | |
575 | { | |
576 | out->key = in->key; | |
577 | out->uid = in->uid; | |
578 | out->gid = in->gid; | |
579 | out->cuid = in->cuid; | |
580 | out->cgid = in->cgid; | |
581 | out->mode = in->mode; | |
582 | out->seq = in->seq; | |
583 | } | |
584 | ||
585 | /** | |
586 | * ipc64_perm_to_ipc_perm - convert old ipc permissions to new | |
587 | * @in: new style IPC permissions | |
588 | * @out: old style IPC permissions | |
589 | * | |
72fd4a35 RD |
590 | * Turn the new style permissions object @in into a compatibility |
591 | * object and store it into the @out pointer. | |
1da177e4 LT |
592 | */ |
593 | ||
594 | void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out) | |
595 | { | |
596 | out->key = in->key; | |
597 | SET_UID(out->uid, in->uid); | |
598 | SET_GID(out->gid, in->gid); | |
599 | SET_UID(out->cuid, in->cuid); | |
600 | SET_GID(out->cgid, in->cgid); | |
601 | out->mode = in->mode; | |
602 | out->seq = in->seq; | |
603 | } | |
604 | ||
605 | /* | |
606 | * So far only shm_get_stat() calls ipc_get() via shm_get(), so ipc_get() | |
5f921ae9 IM |
607 | * is called with shm_ids.mutex locked. Since grow_ary() is also called with |
608 | * shm_ids.mutex down(for Shared Memory), there is no need to add read | |
1da177e4 LT |
609 | * barriers here to gurantee the writes in grow_ary() are seen in order |
610 | * here (for Alpha). | |
611 | * | |
5f921ae9 IM |
612 | * However ipc_get() itself does not necessary require ipc_ids.mutex down. So |
613 | * if in the future ipc_get() is used by other places without ipc_ids.mutex | |
1da177e4 LT |
614 | * down, then ipc_get() needs read memery barriers as ipc_lock() does. |
615 | */ | |
616 | struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id) | |
617 | { | |
618 | struct kern_ipc_perm* out; | |
619 | int lid = id % SEQ_MULTIPLIER; | |
620 | if(lid >= ids->entries->size) | |
621 | return NULL; | |
622 | out = ids->entries->p[lid]; | |
623 | return out; | |
624 | } | |
625 | ||
626 | struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id) | |
627 | { | |
628 | struct kern_ipc_perm* out; | |
629 | int lid = id % SEQ_MULTIPLIER; | |
630 | struct ipc_id_ary* entries; | |
631 | ||
632 | rcu_read_lock(); | |
633 | entries = rcu_dereference(ids->entries); | |
634 | if(lid >= entries->size) { | |
635 | rcu_read_unlock(); | |
636 | return NULL; | |
637 | } | |
638 | out = entries->p[lid]; | |
639 | if(out == NULL) { | |
640 | rcu_read_unlock(); | |
641 | return NULL; | |
642 | } | |
643 | spin_lock(&out->lock); | |
644 | ||
645 | /* ipc_rmid() may have already freed the ID while ipc_lock | |
646 | * was spinning: here verify that the structure is still valid | |
647 | */ | |
648 | if (out->deleted) { | |
649 | spin_unlock(&out->lock); | |
650 | rcu_read_unlock(); | |
651 | return NULL; | |
652 | } | |
653 | return out; | |
654 | } | |
655 | ||
656 | void ipc_lock_by_ptr(struct kern_ipc_perm *perm) | |
657 | { | |
658 | rcu_read_lock(); | |
659 | spin_lock(&perm->lock); | |
660 | } | |
661 | ||
662 | void ipc_unlock(struct kern_ipc_perm* perm) | |
663 | { | |
664 | spin_unlock(&perm->lock); | |
665 | rcu_read_unlock(); | |
666 | } | |
667 | ||
668 | int ipc_buildid(struct ipc_ids* ids, int id, int seq) | |
669 | { | |
670 | return SEQ_MULTIPLIER*seq + id; | |
671 | } | |
672 | ||
673 | int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid) | |
674 | { | |
675 | if(uid/SEQ_MULTIPLIER != ipcp->seq) | |
676 | return 1; | |
677 | return 0; | |
678 | } | |
679 | ||
680 | #ifdef __ARCH_WANT_IPC_PARSE_VERSION | |
681 | ||
682 | ||
683 | /** | |
684 | * ipc_parse_version - IPC call version | |
685 | * @cmd: pointer to command | |
686 | * | |
687 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. | |
72fd4a35 | 688 | * The @cmd value is turned from an encoding command and version into |
1da177e4 LT |
689 | * just the command code. |
690 | */ | |
691 | ||
692 | int ipc_parse_version (int *cmd) | |
693 | { | |
694 | if (*cmd & IPC_64) { | |
695 | *cmd ^= IPC_64; | |
696 | return IPC_64; | |
697 | } else { | |
698 | return IPC_OLD; | |
699 | } | |
700 | } | |
701 | ||
702 | #endif /* __ARCH_WANT_IPC_PARSE_VERSION */ | |
ae781774 MW |
703 | |
704 | #ifdef CONFIG_PROC_FS | |
bc1fc6d8 EB |
705 | struct ipc_proc_iter { |
706 | struct ipc_namespace *ns; | |
707 | struct ipc_proc_iface *iface; | |
708 | }; | |
709 | ||
ae781774 MW |
710 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
711 | { | |
bc1fc6d8 EB |
712 | struct ipc_proc_iter *iter = s->private; |
713 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
714 | struct kern_ipc_perm *ipc = it; |
715 | loff_t p; | |
73ea4130 KK |
716 | struct ipc_ids *ids; |
717 | ||
bc1fc6d8 | 718 | ids = iter->ns->ids[iface->ids]; |
ae781774 MW |
719 | |
720 | /* If we had an ipc id locked before, unlock it */ | |
721 | if (ipc && ipc != SEQ_START_TOKEN) | |
722 | ipc_unlock(ipc); | |
723 | ||
724 | /* | |
725 | * p = *pos - 1 (because id 0 starts at position 1) | |
726 | * + 1 (because we increment the position by one) | |
727 | */ | |
73ea4130 KK |
728 | for (p = *pos; p <= ids->max_id; p++) { |
729 | if ((ipc = ipc_lock(ids, p)) != NULL) { | |
ae781774 MW |
730 | *pos = p + 1; |
731 | return ipc; | |
732 | } | |
733 | } | |
734 | ||
735 | /* Out of range - return NULL to terminate iteration */ | |
736 | return NULL; | |
737 | } | |
738 | ||
739 | /* | |
740 | * File positions: pos 0 -> header, pos n -> ipc id + 1. | |
741 | * SeqFile iterator: iterator value locked shp or SEQ_TOKEN_START. | |
742 | */ | |
743 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) | |
744 | { | |
bc1fc6d8 EB |
745 | struct ipc_proc_iter *iter = s->private; |
746 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
747 | struct kern_ipc_perm *ipc; |
748 | loff_t p; | |
73ea4130 KK |
749 | struct ipc_ids *ids; |
750 | ||
bc1fc6d8 | 751 | ids = iter->ns->ids[iface->ids]; |
ae781774 MW |
752 | |
753 | /* | |
754 | * Take the lock - this will be released by the corresponding | |
755 | * call to stop(). | |
756 | */ | |
73ea4130 | 757 | mutex_lock(&ids->mutex); |
ae781774 MW |
758 | |
759 | /* pos < 0 is invalid */ | |
760 | if (*pos < 0) | |
761 | return NULL; | |
762 | ||
763 | /* pos == 0 means header */ | |
764 | if (*pos == 0) | |
765 | return SEQ_START_TOKEN; | |
766 | ||
767 | /* Find the (pos-1)th ipc */ | |
73ea4130 KK |
768 | for (p = *pos - 1; p <= ids->max_id; p++) { |
769 | if ((ipc = ipc_lock(ids, p)) != NULL) { | |
ae781774 MW |
770 | *pos = p + 1; |
771 | return ipc; | |
772 | } | |
773 | } | |
774 | return NULL; | |
775 | } | |
776 | ||
777 | static void sysvipc_proc_stop(struct seq_file *s, void *it) | |
778 | { | |
779 | struct kern_ipc_perm *ipc = it; | |
bc1fc6d8 EB |
780 | struct ipc_proc_iter *iter = s->private; |
781 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 | 782 | struct ipc_ids *ids; |
ae781774 MW |
783 | |
784 | /* If we had a locked segment, release it */ | |
785 | if (ipc && ipc != SEQ_START_TOKEN) | |
786 | ipc_unlock(ipc); | |
787 | ||
bc1fc6d8 | 788 | ids = iter->ns->ids[iface->ids]; |
ae781774 | 789 | /* Release the lock we took in start() */ |
73ea4130 | 790 | mutex_unlock(&ids->mutex); |
ae781774 MW |
791 | } |
792 | ||
793 | static int sysvipc_proc_show(struct seq_file *s, void *it) | |
794 | { | |
bc1fc6d8 EB |
795 | struct ipc_proc_iter *iter = s->private; |
796 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
797 | |
798 | if (it == SEQ_START_TOKEN) | |
799 | return seq_puts(s, iface->header); | |
800 | ||
801 | return iface->show(s, it); | |
802 | } | |
803 | ||
804 | static struct seq_operations sysvipc_proc_seqops = { | |
805 | .start = sysvipc_proc_start, | |
806 | .stop = sysvipc_proc_stop, | |
807 | .next = sysvipc_proc_next, | |
808 | .show = sysvipc_proc_show, | |
809 | }; | |
810 | ||
bc1fc6d8 EB |
811 | static int sysvipc_proc_open(struct inode *inode, struct file *file) |
812 | { | |
ae781774 MW |
813 | int ret; |
814 | struct seq_file *seq; | |
bc1fc6d8 EB |
815 | struct ipc_proc_iter *iter; |
816 | ||
817 | ret = -ENOMEM; | |
818 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
819 | if (!iter) | |
820 | goto out; | |
ae781774 MW |
821 | |
822 | ret = seq_open(file, &sysvipc_proc_seqops); | |
bc1fc6d8 EB |
823 | if (ret) |
824 | goto out_kfree; | |
825 | ||
826 | seq = file->private_data; | |
827 | seq->private = iter; | |
828 | ||
829 | iter->iface = PDE(inode)->data; | |
830 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); | |
831 | out: | |
ae781774 | 832 | return ret; |
bc1fc6d8 EB |
833 | out_kfree: |
834 | kfree(iter); | |
835 | goto out; | |
836 | } | |
837 | ||
838 | static int sysvipc_proc_release(struct inode *inode, struct file *file) | |
839 | { | |
840 | struct seq_file *seq = file->private_data; | |
841 | struct ipc_proc_iter *iter = seq->private; | |
842 | put_ipc_ns(iter->ns); | |
843 | return seq_release_private(inode, file); | |
ae781774 MW |
844 | } |
845 | ||
9a32144e | 846 | static const struct file_operations sysvipc_proc_fops = { |
ae781774 MW |
847 | .open = sysvipc_proc_open, |
848 | .read = seq_read, | |
849 | .llseek = seq_lseek, | |
bc1fc6d8 | 850 | .release = sysvipc_proc_release, |
ae781774 MW |
851 | }; |
852 | #endif /* CONFIG_PROC_FS */ |