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 | ||
53 | #ifdef CONFIG_IPC_NS | |
54 | static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns) | |
55 | { | |
56 | int err; | |
57 | struct ipc_namespace *ns; | |
58 | ||
59 | err = -ENOMEM; | |
60 | ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL); | |
61 | if (ns == NULL) | |
62 | goto err_mem; | |
63 | ||
64 | err = sem_init_ns(ns); | |
65 | if (err) | |
66 | goto err_sem; | |
67 | err = msg_init_ns(ns); | |
68 | if (err) | |
69 | goto err_msg; | |
70 | err = shm_init_ns(ns); | |
71 | if (err) | |
72 | goto err_shm; | |
73 | ||
74 | kref_init(&ns->kref); | |
75 | return ns; | |
76 | ||
77 | err_shm: | |
78 | msg_exit_ns(ns); | |
79 | err_msg: | |
80 | sem_exit_ns(ns); | |
81 | err_sem: | |
82 | kfree(ns); | |
83 | err_mem: | |
84 | return ERR_PTR(err); | |
85 | } | |
86 | ||
e3222c4e | 87 | struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns) |
73ea4130 | 88 | { |
73ea4130 | 89 | struct ipc_namespace *new_ns; |
73ea4130 | 90 | |
e3222c4e BP |
91 | BUG_ON(!ns); |
92 | get_ipc_ns(ns); | |
73ea4130 KK |
93 | |
94 | if (!(flags & CLONE_NEWIPC)) | |
e3222c4e BP |
95 | return ns; |
96 | ||
97 | new_ns = clone_ipc_ns(ns); | |
98 | ||
99 | put_ipc_ns(ns); | |
100 | return new_ns; | |
73ea4130 KK |
101 | } |
102 | ||
103 | void free_ipc_ns(struct kref *kref) | |
104 | { | |
105 | struct ipc_namespace *ns; | |
106 | ||
107 | ns = container_of(kref, struct ipc_namespace, kref); | |
108 | sem_exit_ns(ns); | |
109 | msg_exit_ns(ns); | |
110 | shm_exit_ns(ns); | |
111 | kfree(ns); | |
112 | } | |
a28d193c | 113 | #else |
e3222c4e | 114 | struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns) |
a28d193c SH |
115 | { |
116 | if (flags & CLONE_NEWIPC) | |
e3222c4e BP |
117 | return ERR_PTR(-EINVAL); |
118 | return ns; | |
a28d193c | 119 | } |
73ea4130 KK |
120 | #endif |
121 | ||
1da177e4 LT |
122 | /** |
123 | * ipc_init - initialise IPC subsystem | |
124 | * | |
125 | * The various system5 IPC resources (semaphores, messages and shared | |
72fd4a35 | 126 | * memory) are initialised |
1da177e4 LT |
127 | */ |
128 | ||
129 | static int __init ipc_init(void) | |
130 | { | |
131 | sem_init(); | |
132 | msg_init(); | |
133 | shm_init(); | |
134 | return 0; | |
135 | } | |
136 | __initcall(ipc_init); | |
137 | ||
138 | /** | |
139 | * ipc_init_ids - initialise IPC identifiers | |
140 | * @ids: Identifier set | |
141 | * @size: Number of identifiers | |
142 | * | |
143 | * Given a size for the ipc identifier range (limited below IPCMNI) | |
144 | * set up the sequence range to use then allocate and initialise the | |
145 | * array itself. | |
146 | */ | |
147 | ||
73ea4130 | 148 | void __ipc_init ipc_init_ids(struct ipc_ids* ids, int size) |
1da177e4 LT |
149 | { |
150 | int i; | |
5f921ae9 IM |
151 | |
152 | mutex_init(&ids->mutex); | |
1da177e4 LT |
153 | |
154 | if(size > IPCMNI) | |
155 | size = IPCMNI; | |
156 | ids->in_use = 0; | |
157 | ids->max_id = -1; | |
158 | ids->seq = 0; | |
159 | { | |
160 | int seq_limit = INT_MAX/SEQ_MULTIPLIER; | |
161 | if(seq_limit > USHRT_MAX) | |
162 | ids->seq_max = USHRT_MAX; | |
163 | else | |
164 | ids->seq_max = seq_limit; | |
165 | } | |
166 | ||
167 | ids->entries = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*size + | |
168 | sizeof(struct ipc_id_ary)); | |
169 | ||
170 | if(ids->entries == NULL) { | |
171 | printk(KERN_ERR "ipc_init_ids() failed, ipc service disabled.\n"); | |
172 | size = 0; | |
173 | ids->entries = &ids->nullentry; | |
174 | } | |
175 | ids->entries->size = size; | |
176 | for(i=0;i<size;i++) | |
177 | ids->entries->p[i] = NULL; | |
178 | } | |
179 | ||
ae781774 | 180 | #ifdef CONFIG_PROC_FS |
9a32144e | 181 | static const struct file_operations sysvipc_proc_fops; |
ae781774 | 182 | /** |
72fd4a35 | 183 | * ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface. |
ae781774 MW |
184 | * @path: Path in procfs |
185 | * @header: Banner to be printed at the beginning of the file. | |
186 | * @ids: ipc id table to iterate. | |
187 | * @show: show routine. | |
188 | */ | |
189 | void __init ipc_init_proc_interface(const char *path, const char *header, | |
73ea4130 | 190 | int ids, int (*show)(struct seq_file *, void *)) |
ae781774 MW |
191 | { |
192 | struct proc_dir_entry *pde; | |
193 | struct ipc_proc_iface *iface; | |
194 | ||
195 | iface = kmalloc(sizeof(*iface), GFP_KERNEL); | |
196 | if (!iface) | |
197 | return; | |
198 | iface->path = path; | |
199 | iface->header = header; | |
200 | iface->ids = ids; | |
201 | iface->show = show; | |
202 | ||
203 | pde = create_proc_entry(path, | |
204 | S_IRUGO, /* world readable */ | |
205 | NULL /* parent dir */); | |
206 | if (pde) { | |
207 | pde->data = iface; | |
208 | pde->proc_fops = &sysvipc_proc_fops; | |
209 | } else { | |
210 | kfree(iface); | |
211 | } | |
212 | } | |
213 | #endif | |
214 | ||
1da177e4 LT |
215 | /** |
216 | * ipc_findkey - find a key in an ipc identifier set | |
217 | * @ids: Identifier set | |
218 | * @key: The key to find | |
219 | * | |
5f921ae9 | 220 | * Requires ipc_ids.mutex locked. |
1da177e4 LT |
221 | * Returns the identifier if found or -1 if not. |
222 | */ | |
223 | ||
224 | int ipc_findkey(struct ipc_ids* ids, key_t key) | |
225 | { | |
226 | int id; | |
227 | struct kern_ipc_perm* p; | |
228 | int max_id = ids->max_id; | |
229 | ||
230 | /* | |
231 | * rcu_dereference() is not needed here | |
5f921ae9 | 232 | * since ipc_ids.mutex is held |
1da177e4 LT |
233 | */ |
234 | for (id = 0; id <= max_id; id++) { | |
235 | p = ids->entries->p[id]; | |
236 | if(p==NULL) | |
237 | continue; | |
238 | if (key == p->key) | |
239 | return id; | |
240 | } | |
241 | return -1; | |
242 | } | |
243 | ||
244 | /* | |
5f921ae9 | 245 | * Requires ipc_ids.mutex locked |
1da177e4 LT |
246 | */ |
247 | static int grow_ary(struct ipc_ids* ids, int newsize) | |
248 | { | |
249 | struct ipc_id_ary* new; | |
250 | struct ipc_id_ary* old; | |
251 | int i; | |
252 | int size = ids->entries->size; | |
253 | ||
254 | if(newsize > IPCMNI) | |
255 | newsize = IPCMNI; | |
256 | if(newsize <= size) | |
257 | return newsize; | |
258 | ||
259 | new = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*newsize + | |
260 | sizeof(struct ipc_id_ary)); | |
261 | if(new == NULL) | |
262 | return size; | |
263 | new->size = newsize; | |
a9a5cd5d | 264 | memcpy(new->p, ids->entries->p, sizeof(struct kern_ipc_perm *)*size); |
1da177e4 LT |
265 | for(i=size;i<newsize;i++) { |
266 | new->p[i] = NULL; | |
267 | } | |
268 | old = ids->entries; | |
269 | ||
270 | /* | |
271 | * Use rcu_assign_pointer() to make sure the memcpyed contents | |
272 | * of the new array are visible before the new array becomes visible. | |
273 | */ | |
274 | rcu_assign_pointer(ids->entries, new); | |
275 | ||
c7e12b83 | 276 | __ipc_fini_ids(ids, old); |
1da177e4 LT |
277 | return newsize; |
278 | } | |
279 | ||
280 | /** | |
281 | * ipc_addid - add an IPC identifier | |
282 | * @ids: IPC identifier set | |
283 | * @new: new IPC permission set | |
284 | * @size: new size limit for the id array | |
285 | * | |
286 | * Add an entry 'new' to the IPC arrays. The permissions object is | |
287 | * initialised and the first free entry is set up and the id assigned | |
288 | * is returned. The list is returned in a locked state on success. | |
289 | * On failure the list is not locked and -1 is returned. | |
290 | * | |
5f921ae9 | 291 | * Called with ipc_ids.mutex held. |
1da177e4 LT |
292 | */ |
293 | ||
294 | int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) | |
295 | { | |
296 | int id; | |
297 | ||
298 | size = grow_ary(ids,size); | |
299 | ||
300 | /* | |
301 | * rcu_dereference()() is not needed here since | |
5f921ae9 | 302 | * ipc_ids.mutex is held |
1da177e4 LT |
303 | */ |
304 | for (id = 0; id < size; id++) { | |
305 | if(ids->entries->p[id] == NULL) | |
306 | goto found; | |
307 | } | |
308 | return -1; | |
309 | found: | |
310 | ids->in_use++; | |
311 | if (id > ids->max_id) | |
312 | ids->max_id = id; | |
313 | ||
314 | new->cuid = new->uid = current->euid; | |
315 | new->gid = new->cgid = current->egid; | |
316 | ||
317 | new->seq = ids->seq++; | |
318 | if(ids->seq > ids->seq_max) | |
319 | ids->seq = 0; | |
320 | ||
321 | spin_lock_init(&new->lock); | |
322 | new->deleted = 0; | |
323 | rcu_read_lock(); | |
324 | spin_lock(&new->lock); | |
325 | ids->entries->p[id] = new; | |
326 | return id; | |
327 | } | |
328 | ||
329 | /** | |
330 | * ipc_rmid - remove an IPC identifier | |
331 | * @ids: identifier set | |
332 | * @id: Identifier to remove | |
333 | * | |
334 | * The identifier must be valid, and in use. The kernel will panic if | |
335 | * fed an invalid identifier. The entry is removed and internal | |
336 | * variables recomputed. The object associated with the identifier | |
337 | * is returned. | |
5f921ae9 | 338 | * ipc_ids.mutex and the spinlock for this ID is hold before this function |
1da177e4 LT |
339 | * is called, and remain locked on the exit. |
340 | */ | |
341 | ||
342 | struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id) | |
343 | { | |
344 | struct kern_ipc_perm* p; | |
345 | int lid = id % SEQ_MULTIPLIER; | |
9bc98fc6 | 346 | BUG_ON(lid >= ids->entries->size); |
1da177e4 LT |
347 | |
348 | /* | |
349 | * do not need a rcu_dereference()() here to force ordering | |
5f921ae9 | 350 | * on Alpha, since the ipc_ids.mutex is held. |
1da177e4 LT |
351 | */ |
352 | p = ids->entries->p[lid]; | |
353 | ids->entries->p[lid] = NULL; | |
9bc98fc6 | 354 | BUG_ON(p==NULL); |
1da177e4 LT |
355 | ids->in_use--; |
356 | ||
357 | if (lid == ids->max_id) { | |
358 | do { | |
359 | lid--; | |
360 | if(lid == -1) | |
361 | break; | |
362 | } while (ids->entries->p[lid] == NULL); | |
363 | ids->max_id = lid; | |
364 | } | |
365 | p->deleted = 1; | |
366 | return p; | |
367 | } | |
368 | ||
369 | /** | |
370 | * ipc_alloc - allocate ipc space | |
371 | * @size: size desired | |
372 | * | |
373 | * Allocate memory from the appropriate pools and return a pointer to it. | |
374 | * NULL is returned if the allocation fails | |
375 | */ | |
376 | ||
377 | void* ipc_alloc(int size) | |
378 | { | |
379 | void* out; | |
380 | if(size > PAGE_SIZE) | |
381 | out = vmalloc(size); | |
382 | else | |
383 | out = kmalloc(size, GFP_KERNEL); | |
384 | return out; | |
385 | } | |
386 | ||
387 | /** | |
388 | * ipc_free - free ipc space | |
389 | * @ptr: pointer returned by ipc_alloc | |
390 | * @size: size of block | |
391 | * | |
72fd4a35 | 392 | * Free a block created with ipc_alloc(). The caller must know the size |
1da177e4 LT |
393 | * used in the allocation call. |
394 | */ | |
395 | ||
396 | void ipc_free(void* ptr, int size) | |
397 | { | |
398 | if(size > PAGE_SIZE) | |
399 | vfree(ptr); | |
400 | else | |
401 | kfree(ptr); | |
402 | } | |
403 | ||
404 | /* | |
405 | * rcu allocations: | |
406 | * There are three headers that are prepended to the actual allocation: | |
407 | * - during use: ipc_rcu_hdr. | |
408 | * - during the rcu grace period: ipc_rcu_grace. | |
409 | * - [only if vmalloc]: ipc_rcu_sched. | |
410 | * Their lifetime doesn't overlap, thus the headers share the same memory. | |
411 | * Unlike a normal union, they are right-aligned, thus some container_of | |
412 | * forward/backward casting is necessary: | |
413 | */ | |
414 | struct ipc_rcu_hdr | |
415 | { | |
416 | int refcount; | |
417 | int is_vmalloc; | |
418 | void *data[0]; | |
419 | }; | |
420 | ||
421 | ||
422 | struct ipc_rcu_grace | |
423 | { | |
424 | struct rcu_head rcu; | |
425 | /* "void *" makes sure alignment of following data is sane. */ | |
426 | void *data[0]; | |
427 | }; | |
428 | ||
429 | struct ipc_rcu_sched | |
430 | { | |
431 | struct work_struct work; | |
432 | /* "void *" makes sure alignment of following data is sane. */ | |
433 | void *data[0]; | |
434 | }; | |
435 | ||
436 | #define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \ | |
437 | sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr)) | |
438 | #define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \ | |
439 | sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC) | |
440 | ||
441 | static inline int rcu_use_vmalloc(int size) | |
442 | { | |
443 | /* Too big for a single page? */ | |
444 | if (HDRLEN_KMALLOC + size > PAGE_SIZE) | |
445 | return 1; | |
446 | return 0; | |
447 | } | |
448 | ||
449 | /** | |
450 | * ipc_rcu_alloc - allocate ipc and rcu space | |
451 | * @size: size desired | |
452 | * | |
453 | * Allocate memory for the rcu header structure + the object. | |
454 | * Returns the pointer to the object. | |
455 | * NULL is returned if the allocation fails. | |
456 | */ | |
457 | ||
458 | void* ipc_rcu_alloc(int size) | |
459 | { | |
460 | void* out; | |
461 | /* | |
462 | * We prepend the allocation with the rcu struct, and | |
463 | * workqueue if necessary (for vmalloc). | |
464 | */ | |
465 | if (rcu_use_vmalloc(size)) { | |
466 | out = vmalloc(HDRLEN_VMALLOC + size); | |
467 | if (out) { | |
468 | out += HDRLEN_VMALLOC; | |
469 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1; | |
470 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
471 | } | |
472 | } else { | |
473 | out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL); | |
474 | if (out) { | |
475 | out += HDRLEN_KMALLOC; | |
476 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0; | |
477 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
478 | } | |
479 | } | |
480 | ||
481 | return out; | |
482 | } | |
483 | ||
484 | void ipc_rcu_getref(void *ptr) | |
485 | { | |
486 | container_of(ptr, struct ipc_rcu_hdr, data)->refcount++; | |
487 | } | |
488 | ||
65f27f38 DH |
489 | static void ipc_do_vfree(struct work_struct *work) |
490 | { | |
491 | vfree(container_of(work, struct ipc_rcu_sched, work)); | |
492 | } | |
493 | ||
1da177e4 | 494 | /** |
1e5d5331 RD |
495 | * ipc_schedule_free - free ipc + rcu space |
496 | * @head: RCU callback structure for queued work | |
1da177e4 LT |
497 | * |
498 | * Since RCU callback function is called in bh, | |
72fd4a35 | 499 | * we need to defer the vfree to schedule_work(). |
1da177e4 LT |
500 | */ |
501 | static void ipc_schedule_free(struct rcu_head *head) | |
502 | { | |
503 | struct ipc_rcu_grace *grace = | |
504 | container_of(head, struct ipc_rcu_grace, rcu); | |
505 | struct ipc_rcu_sched *sched = | |
506 | container_of(&(grace->data[0]), struct ipc_rcu_sched, data[0]); | |
507 | ||
65f27f38 | 508 | INIT_WORK(&sched->work, ipc_do_vfree); |
1da177e4 LT |
509 | schedule_work(&sched->work); |
510 | } | |
511 | ||
512 | /** | |
1e5d5331 RD |
513 | * ipc_immediate_free - free ipc + rcu space |
514 | * @head: RCU callback structure that contains pointer to be freed | |
1da177e4 | 515 | * |
72fd4a35 | 516 | * Free from the RCU callback context. |
1da177e4 LT |
517 | */ |
518 | static void ipc_immediate_free(struct rcu_head *head) | |
519 | { | |
520 | struct ipc_rcu_grace *free = | |
521 | container_of(head, struct ipc_rcu_grace, rcu); | |
522 | kfree(free); | |
523 | } | |
524 | ||
525 | void ipc_rcu_putref(void *ptr) | |
526 | { | |
527 | if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0) | |
528 | return; | |
529 | ||
530 | if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) { | |
531 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
532 | ipc_schedule_free); | |
533 | } else { | |
534 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
535 | ipc_immediate_free); | |
536 | } | |
537 | } | |
538 | ||
539 | /** | |
540 | * ipcperms - check IPC permissions | |
541 | * @ipcp: IPC permission set | |
542 | * @flag: desired permission set. | |
543 | * | |
544 | * Check user, group, other permissions for access | |
545 | * to ipc resources. return 0 if allowed | |
546 | */ | |
547 | ||
548 | int ipcperms (struct kern_ipc_perm *ipcp, short flag) | |
549 | { /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */ | |
073115d6 | 550 | int requested_mode, granted_mode, err; |
1da177e4 | 551 | |
073115d6 SG |
552 | if (unlikely((err = audit_ipc_obj(ipcp)))) |
553 | return err; | |
1da177e4 LT |
554 | requested_mode = (flag >> 6) | (flag >> 3) | flag; |
555 | granted_mode = ipcp->mode; | |
556 | if (current->euid == ipcp->cuid || current->euid == ipcp->uid) | |
557 | granted_mode >>= 6; | |
558 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) | |
559 | granted_mode >>= 3; | |
560 | /* is there some bit set in requested_mode but not in granted_mode? */ | |
561 | if ((requested_mode & ~granted_mode & 0007) && | |
562 | !capable(CAP_IPC_OWNER)) | |
563 | return -1; | |
564 | ||
565 | return security_ipc_permission(ipcp, flag); | |
566 | } | |
567 | ||
568 | /* | |
569 | * Functions to convert between the kern_ipc_perm structure and the | |
570 | * old/new ipc_perm structures | |
571 | */ | |
572 | ||
573 | /** | |
574 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user | |
575 | * @in: kernel permissions | |
576 | * @out: new style IPC permissions | |
577 | * | |
72fd4a35 RD |
578 | * Turn the kernel object @in into a set of permissions descriptions |
579 | * for returning to userspace (@out). | |
1da177e4 LT |
580 | */ |
581 | ||
582 | ||
583 | void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out) | |
584 | { | |
585 | out->key = in->key; | |
586 | out->uid = in->uid; | |
587 | out->gid = in->gid; | |
588 | out->cuid = in->cuid; | |
589 | out->cgid = in->cgid; | |
590 | out->mode = in->mode; | |
591 | out->seq = in->seq; | |
592 | } | |
593 | ||
594 | /** | |
595 | * ipc64_perm_to_ipc_perm - convert old ipc permissions to new | |
596 | * @in: new style IPC permissions | |
597 | * @out: old style IPC permissions | |
598 | * | |
72fd4a35 RD |
599 | * Turn the new style permissions object @in into a compatibility |
600 | * object and store it into the @out pointer. | |
1da177e4 LT |
601 | */ |
602 | ||
603 | void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out) | |
604 | { | |
605 | out->key = in->key; | |
606 | SET_UID(out->uid, in->uid); | |
607 | SET_GID(out->gid, in->gid); | |
608 | SET_UID(out->cuid, in->cuid); | |
609 | SET_GID(out->cgid, in->cgid); | |
610 | out->mode = in->mode; | |
611 | out->seq = in->seq; | |
612 | } | |
613 | ||
614 | /* | |
615 | * So far only shm_get_stat() calls ipc_get() via shm_get(), so ipc_get() | |
5f921ae9 IM |
616 | * is called with shm_ids.mutex locked. Since grow_ary() is also called with |
617 | * shm_ids.mutex down(for Shared Memory), there is no need to add read | |
1da177e4 LT |
618 | * barriers here to gurantee the writes in grow_ary() are seen in order |
619 | * here (for Alpha). | |
620 | * | |
5f921ae9 IM |
621 | * However ipc_get() itself does not necessary require ipc_ids.mutex down. So |
622 | * if in the future ipc_get() is used by other places without ipc_ids.mutex | |
1da177e4 LT |
623 | * down, then ipc_get() needs read memery barriers as ipc_lock() does. |
624 | */ | |
625 | struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id) | |
626 | { | |
627 | struct kern_ipc_perm* out; | |
628 | int lid = id % SEQ_MULTIPLIER; | |
629 | if(lid >= ids->entries->size) | |
630 | return NULL; | |
631 | out = ids->entries->p[lid]; | |
632 | return out; | |
633 | } | |
634 | ||
635 | struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id) | |
636 | { | |
637 | struct kern_ipc_perm* out; | |
638 | int lid = id % SEQ_MULTIPLIER; | |
639 | struct ipc_id_ary* entries; | |
640 | ||
641 | rcu_read_lock(); | |
642 | entries = rcu_dereference(ids->entries); | |
643 | if(lid >= entries->size) { | |
644 | rcu_read_unlock(); | |
645 | return NULL; | |
646 | } | |
647 | out = entries->p[lid]; | |
648 | if(out == NULL) { | |
649 | rcu_read_unlock(); | |
650 | return NULL; | |
651 | } | |
652 | spin_lock(&out->lock); | |
653 | ||
654 | /* ipc_rmid() may have already freed the ID while ipc_lock | |
655 | * was spinning: here verify that the structure is still valid | |
656 | */ | |
657 | if (out->deleted) { | |
658 | spin_unlock(&out->lock); | |
659 | rcu_read_unlock(); | |
660 | return NULL; | |
661 | } | |
662 | return out; | |
663 | } | |
664 | ||
665 | void ipc_lock_by_ptr(struct kern_ipc_perm *perm) | |
666 | { | |
667 | rcu_read_lock(); | |
668 | spin_lock(&perm->lock); | |
669 | } | |
670 | ||
671 | void ipc_unlock(struct kern_ipc_perm* perm) | |
672 | { | |
673 | spin_unlock(&perm->lock); | |
674 | rcu_read_unlock(); | |
675 | } | |
676 | ||
677 | int ipc_buildid(struct ipc_ids* ids, int id, int seq) | |
678 | { | |
679 | return SEQ_MULTIPLIER*seq + id; | |
680 | } | |
681 | ||
682 | int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid) | |
683 | { | |
684 | if(uid/SEQ_MULTIPLIER != ipcp->seq) | |
685 | return 1; | |
686 | return 0; | |
687 | } | |
688 | ||
689 | #ifdef __ARCH_WANT_IPC_PARSE_VERSION | |
690 | ||
691 | ||
692 | /** | |
693 | * ipc_parse_version - IPC call version | |
694 | * @cmd: pointer to command | |
695 | * | |
696 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. | |
72fd4a35 | 697 | * The @cmd value is turned from an encoding command and version into |
1da177e4 LT |
698 | * just the command code. |
699 | */ | |
700 | ||
701 | int ipc_parse_version (int *cmd) | |
702 | { | |
703 | if (*cmd & IPC_64) { | |
704 | *cmd ^= IPC_64; | |
705 | return IPC_64; | |
706 | } else { | |
707 | return IPC_OLD; | |
708 | } | |
709 | } | |
710 | ||
711 | #endif /* __ARCH_WANT_IPC_PARSE_VERSION */ | |
ae781774 MW |
712 | |
713 | #ifdef CONFIG_PROC_FS | |
bc1fc6d8 EB |
714 | struct ipc_proc_iter { |
715 | struct ipc_namespace *ns; | |
716 | struct ipc_proc_iface *iface; | |
717 | }; | |
718 | ||
ae781774 MW |
719 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
720 | { | |
bc1fc6d8 EB |
721 | struct ipc_proc_iter *iter = s->private; |
722 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
723 | struct kern_ipc_perm *ipc = it; |
724 | loff_t p; | |
73ea4130 KK |
725 | struct ipc_ids *ids; |
726 | ||
bc1fc6d8 | 727 | ids = iter->ns->ids[iface->ids]; |
ae781774 MW |
728 | |
729 | /* If we had an ipc id locked before, unlock it */ | |
730 | if (ipc && ipc != SEQ_START_TOKEN) | |
731 | ipc_unlock(ipc); | |
732 | ||
733 | /* | |
734 | * p = *pos - 1 (because id 0 starts at position 1) | |
735 | * + 1 (because we increment the position by one) | |
736 | */ | |
73ea4130 KK |
737 | for (p = *pos; p <= ids->max_id; p++) { |
738 | if ((ipc = ipc_lock(ids, p)) != NULL) { | |
ae781774 MW |
739 | *pos = p + 1; |
740 | return ipc; | |
741 | } | |
742 | } | |
743 | ||
744 | /* Out of range - return NULL to terminate iteration */ | |
745 | return NULL; | |
746 | } | |
747 | ||
748 | /* | |
749 | * File positions: pos 0 -> header, pos n -> ipc id + 1. | |
750 | * SeqFile iterator: iterator value locked shp or SEQ_TOKEN_START. | |
751 | */ | |
752 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) | |
753 | { | |
bc1fc6d8 EB |
754 | struct ipc_proc_iter *iter = s->private; |
755 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
756 | struct kern_ipc_perm *ipc; |
757 | loff_t p; | |
73ea4130 KK |
758 | struct ipc_ids *ids; |
759 | ||
bc1fc6d8 | 760 | ids = iter->ns->ids[iface->ids]; |
ae781774 MW |
761 | |
762 | /* | |
763 | * Take the lock - this will be released by the corresponding | |
764 | * call to stop(). | |
765 | */ | |
73ea4130 | 766 | mutex_lock(&ids->mutex); |
ae781774 MW |
767 | |
768 | /* pos < 0 is invalid */ | |
769 | if (*pos < 0) | |
770 | return NULL; | |
771 | ||
772 | /* pos == 0 means header */ | |
773 | if (*pos == 0) | |
774 | return SEQ_START_TOKEN; | |
775 | ||
776 | /* Find the (pos-1)th ipc */ | |
73ea4130 KK |
777 | for (p = *pos - 1; p <= ids->max_id; p++) { |
778 | if ((ipc = ipc_lock(ids, p)) != NULL) { | |
ae781774 MW |
779 | *pos = p + 1; |
780 | return ipc; | |
781 | } | |
782 | } | |
783 | return NULL; | |
784 | } | |
785 | ||
786 | static void sysvipc_proc_stop(struct seq_file *s, void *it) | |
787 | { | |
788 | struct kern_ipc_perm *ipc = it; | |
bc1fc6d8 EB |
789 | struct ipc_proc_iter *iter = s->private; |
790 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 | 791 | struct ipc_ids *ids; |
ae781774 MW |
792 | |
793 | /* If we had a locked segment, release it */ | |
794 | if (ipc && ipc != SEQ_START_TOKEN) | |
795 | ipc_unlock(ipc); | |
796 | ||
bc1fc6d8 | 797 | ids = iter->ns->ids[iface->ids]; |
ae781774 | 798 | /* Release the lock we took in start() */ |
73ea4130 | 799 | mutex_unlock(&ids->mutex); |
ae781774 MW |
800 | } |
801 | ||
802 | static int sysvipc_proc_show(struct seq_file *s, void *it) | |
803 | { | |
bc1fc6d8 EB |
804 | struct ipc_proc_iter *iter = s->private; |
805 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
806 | |
807 | if (it == SEQ_START_TOKEN) | |
808 | return seq_puts(s, iface->header); | |
809 | ||
810 | return iface->show(s, it); | |
811 | } | |
812 | ||
813 | static struct seq_operations sysvipc_proc_seqops = { | |
814 | .start = sysvipc_proc_start, | |
815 | .stop = sysvipc_proc_stop, | |
816 | .next = sysvipc_proc_next, | |
817 | .show = sysvipc_proc_show, | |
818 | }; | |
819 | ||
bc1fc6d8 EB |
820 | static int sysvipc_proc_open(struct inode *inode, struct file *file) |
821 | { | |
ae781774 MW |
822 | int ret; |
823 | struct seq_file *seq; | |
bc1fc6d8 EB |
824 | struct ipc_proc_iter *iter; |
825 | ||
826 | ret = -ENOMEM; | |
827 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
828 | if (!iter) | |
829 | goto out; | |
ae781774 MW |
830 | |
831 | ret = seq_open(file, &sysvipc_proc_seqops); | |
bc1fc6d8 EB |
832 | if (ret) |
833 | goto out_kfree; | |
834 | ||
835 | seq = file->private_data; | |
836 | seq->private = iter; | |
837 | ||
838 | iter->iface = PDE(inode)->data; | |
839 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); | |
840 | out: | |
ae781774 | 841 | return ret; |
bc1fc6d8 EB |
842 | out_kfree: |
843 | kfree(iter); | |
844 | goto out; | |
845 | } | |
846 | ||
847 | static int sysvipc_proc_release(struct inode *inode, struct file *file) | |
848 | { | |
849 | struct seq_file *seq = file->private_data; | |
850 | struct ipc_proc_iter *iter = seq->private; | |
851 | put_ipc_ns(iter->ns); | |
852 | return seq_release_private(inode, file); | |
ae781774 MW |
853 | } |
854 | ||
9a32144e | 855 | static const struct file_operations sysvipc_proc_fops = { |
ae781774 MW |
856 | .open = sysvipc_proc_open, |
857 | .read = seq_read, | |
858 | .llseek = seq_lseek, | |
bc1fc6d8 | 859 | .release = sysvipc_proc_release, |
ae781774 MW |
860 | }; |
861 | #endif /* CONFIG_PROC_FS */ |