Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/ipc/shm.c | |
3 | * Copyright (C) 1992, 1993 Krishna Balasubramanian | |
4 | * Many improvements/fixes by Bruno Haible. | |
5 | * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994. | |
6 | * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli. | |
7 | * | |
8 | * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com> | |
9 | * BIGMEM support, Andrea Arcangeli <andrea@suse.de> | |
10 | * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr> | |
11 | * HIGHMEM support, Ingo Molnar <mingo@redhat.com> | |
12 | * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com> | |
13 | * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com> | |
14 | * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com> | |
15 | * | |
16 | */ | |
17 | ||
18 | #include <linux/config.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/mm.h> | |
21 | #include <linux/hugetlb.h> | |
22 | #include <linux/shm.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/file.h> | |
25 | #include <linux/mman.h> | |
26 | #include <linux/proc_fs.h> | |
27 | #include <linux/shmem_fs.h> | |
28 | #include <linux/security.h> | |
29 | #include <linux/syscalls.h> | |
30 | #include <linux/audit.h> | |
7d87e14c SR |
31 | #include <linux/ptrace.h> |
32 | ||
1da177e4 LT |
33 | #include <asm/uaccess.h> |
34 | ||
35 | #include "util.h" | |
36 | ||
37 | #define shm_flags shm_perm.mode | |
38 | ||
39 | static struct file_operations shm_file_operations; | |
40 | static struct vm_operations_struct shm_vm_ops; | |
41 | ||
42 | static struct ipc_ids shm_ids; | |
43 | ||
44 | #define shm_lock(id) ((struct shmid_kernel*)ipc_lock(&shm_ids,id)) | |
45 | #define shm_unlock(shp) ipc_unlock(&(shp)->shm_perm) | |
46 | #define shm_get(id) ((struct shmid_kernel*)ipc_get(&shm_ids,id)) | |
47 | #define shm_buildid(id, seq) \ | |
48 | ipc_buildid(&shm_ids, id, seq) | |
49 | ||
50 | static int newseg (key_t key, int shmflg, size_t size); | |
51 | static void shm_open (struct vm_area_struct *shmd); | |
52 | static void shm_close (struct vm_area_struct *shmd); | |
53 | #ifdef CONFIG_PROC_FS | |
54 | static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data); | |
55 | #endif | |
56 | ||
57 | size_t shm_ctlmax = SHMMAX; | |
58 | size_t shm_ctlall = SHMALL; | |
59 | int shm_ctlmni = SHMMNI; | |
60 | ||
61 | static int shm_tot; /* total number of shared memory pages */ | |
62 | ||
63 | void __init shm_init (void) | |
64 | { | |
65 | ipc_init_ids(&shm_ids, 1); | |
66 | #ifdef CONFIG_PROC_FS | |
67 | create_proc_read_entry("sysvipc/shm", 0, NULL, sysvipc_shm_read_proc, NULL); | |
68 | #endif | |
69 | } | |
70 | ||
71 | static inline int shm_checkid(struct shmid_kernel *s, int id) | |
72 | { | |
73 | if (ipc_checkid(&shm_ids,&s->shm_perm,id)) | |
74 | return -EIDRM; | |
75 | return 0; | |
76 | } | |
77 | ||
78 | static inline struct shmid_kernel *shm_rmid(int id) | |
79 | { | |
80 | return (struct shmid_kernel *)ipc_rmid(&shm_ids,id); | |
81 | } | |
82 | ||
83 | static inline int shm_addid(struct shmid_kernel *shp) | |
84 | { | |
85 | return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni); | |
86 | } | |
87 | ||
88 | ||
89 | ||
90 | static inline void shm_inc (int id) { | |
91 | struct shmid_kernel *shp; | |
92 | ||
93 | if(!(shp = shm_lock(id))) | |
94 | BUG(); | |
95 | shp->shm_atim = get_seconds(); | |
96 | shp->shm_lprid = current->tgid; | |
97 | shp->shm_nattch++; | |
98 | shm_unlock(shp); | |
99 | } | |
100 | ||
101 | /* This is called by fork, once for every shm attach. */ | |
102 | static void shm_open (struct vm_area_struct *shmd) | |
103 | { | |
104 | shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino); | |
105 | } | |
106 | ||
107 | /* | |
108 | * shm_destroy - free the struct shmid_kernel | |
109 | * | |
110 | * @shp: struct to free | |
111 | * | |
112 | * It has to be called with shp and shm_ids.sem locked, | |
113 | * but returns with shp unlocked and freed. | |
114 | */ | |
115 | static void shm_destroy (struct shmid_kernel *shp) | |
116 | { | |
117 | shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
118 | shm_rmid (shp->id); | |
119 | shm_unlock(shp); | |
120 | if (!is_file_hugepages(shp->shm_file)) | |
121 | shmem_lock(shp->shm_file, 0, shp->mlock_user); | |
122 | else | |
123 | user_shm_unlock(shp->shm_file->f_dentry->d_inode->i_size, | |
124 | shp->mlock_user); | |
125 | fput (shp->shm_file); | |
126 | security_shm_free(shp); | |
127 | ipc_rcu_putref(shp); | |
128 | } | |
129 | ||
130 | /* | |
131 | * remove the attach descriptor shmd. | |
132 | * free memory for segment if it is marked destroyed. | |
133 | * The descriptor has already been removed from the current->mm->mmap list | |
134 | * and will later be kfree()d. | |
135 | */ | |
136 | static void shm_close (struct vm_area_struct *shmd) | |
137 | { | |
138 | struct file * file = shmd->vm_file; | |
139 | int id = file->f_dentry->d_inode->i_ino; | |
140 | struct shmid_kernel *shp; | |
141 | ||
142 | down (&shm_ids.sem); | |
143 | /* remove from the list of attaches of the shm segment */ | |
144 | if(!(shp = shm_lock(id))) | |
145 | BUG(); | |
146 | shp->shm_lprid = current->tgid; | |
147 | shp->shm_dtim = get_seconds(); | |
148 | shp->shm_nattch--; | |
149 | if(shp->shm_nattch == 0 && | |
150 | shp->shm_flags & SHM_DEST) | |
151 | shm_destroy (shp); | |
152 | else | |
153 | shm_unlock(shp); | |
154 | up (&shm_ids.sem); | |
155 | } | |
156 | ||
157 | static int shm_mmap(struct file * file, struct vm_area_struct * vma) | |
158 | { | |
159 | file_accessed(file); | |
160 | vma->vm_ops = &shm_vm_ops; | |
161 | shm_inc(file->f_dentry->d_inode->i_ino); | |
162 | return 0; | |
163 | } | |
164 | ||
165 | static struct file_operations shm_file_operations = { | |
166 | .mmap = shm_mmap | |
167 | }; | |
168 | ||
169 | static struct vm_operations_struct shm_vm_ops = { | |
170 | .open = shm_open, /* callback for a new vm-area open */ | |
171 | .close = shm_close, /* callback for when the vm-area is released */ | |
172 | .nopage = shmem_nopage, | |
173 | #ifdef CONFIG_NUMA | |
174 | .set_policy = shmem_set_policy, | |
175 | .get_policy = shmem_get_policy, | |
176 | #endif | |
177 | }; | |
178 | ||
179 | static int newseg (key_t key, int shmflg, size_t size) | |
180 | { | |
181 | int error; | |
182 | struct shmid_kernel *shp; | |
183 | int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT; | |
184 | struct file * file; | |
185 | char name[13]; | |
186 | int id; | |
187 | ||
188 | if (size < SHMMIN || size > shm_ctlmax) | |
189 | return -EINVAL; | |
190 | ||
191 | if (shm_tot + numpages >= shm_ctlall) | |
192 | return -ENOSPC; | |
193 | ||
194 | shp = ipc_rcu_alloc(sizeof(*shp)); | |
195 | if (!shp) | |
196 | return -ENOMEM; | |
197 | ||
198 | shp->shm_perm.key = key; | |
199 | shp->shm_flags = (shmflg & S_IRWXUGO); | |
200 | shp->mlock_user = NULL; | |
201 | ||
202 | shp->shm_perm.security = NULL; | |
203 | error = security_shm_alloc(shp); | |
204 | if (error) { | |
205 | ipc_rcu_putref(shp); | |
206 | return error; | |
207 | } | |
208 | ||
209 | if (shmflg & SHM_HUGETLB) { | |
210 | /* hugetlb_zero_setup takes care of mlock user accounting */ | |
211 | file = hugetlb_zero_setup(size); | |
212 | shp->mlock_user = current->user; | |
213 | } else { | |
214 | sprintf (name, "SYSV%08x", key); | |
215 | file = shmem_file_setup(name, size, VM_ACCOUNT); | |
216 | } | |
217 | error = PTR_ERR(file); | |
218 | if (IS_ERR(file)) | |
219 | goto no_file; | |
220 | ||
221 | error = -ENOSPC; | |
222 | id = shm_addid(shp); | |
223 | if(id == -1) | |
224 | goto no_id; | |
225 | ||
226 | shp->shm_cprid = current->tgid; | |
227 | shp->shm_lprid = 0; | |
228 | shp->shm_atim = shp->shm_dtim = 0; | |
229 | shp->shm_ctim = get_seconds(); | |
230 | shp->shm_segsz = size; | |
231 | shp->shm_nattch = 0; | |
232 | shp->id = shm_buildid(id,shp->shm_perm.seq); | |
233 | shp->shm_file = file; | |
234 | file->f_dentry->d_inode->i_ino = shp->id; | |
235 | if (shmflg & SHM_HUGETLB) | |
236 | set_file_hugepages(file); | |
237 | else | |
238 | file->f_op = &shm_file_operations; | |
239 | shm_tot += numpages; | |
240 | shm_unlock(shp); | |
241 | return shp->id; | |
242 | ||
243 | no_id: | |
244 | fput(file); | |
245 | no_file: | |
246 | security_shm_free(shp); | |
247 | ipc_rcu_putref(shp); | |
248 | return error; | |
249 | } | |
250 | ||
251 | asmlinkage long sys_shmget (key_t key, size_t size, int shmflg) | |
252 | { | |
253 | struct shmid_kernel *shp; | |
254 | int err, id = 0; | |
255 | ||
256 | down(&shm_ids.sem); | |
257 | if (key == IPC_PRIVATE) { | |
258 | err = newseg(key, shmflg, size); | |
259 | } else if ((id = ipc_findkey(&shm_ids, key)) == -1) { | |
260 | if (!(shmflg & IPC_CREAT)) | |
261 | err = -ENOENT; | |
262 | else | |
263 | err = newseg(key, shmflg, size); | |
264 | } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) { | |
265 | err = -EEXIST; | |
266 | } else { | |
267 | shp = shm_lock(id); | |
268 | if(shp==NULL) | |
269 | BUG(); | |
270 | if (shp->shm_segsz < size) | |
271 | err = -EINVAL; | |
272 | else if (ipcperms(&shp->shm_perm, shmflg)) | |
273 | err = -EACCES; | |
274 | else { | |
275 | int shmid = shm_buildid(id, shp->shm_perm.seq); | |
276 | err = security_shm_associate(shp, shmflg); | |
277 | if (!err) | |
278 | err = shmid; | |
279 | } | |
280 | shm_unlock(shp); | |
281 | } | |
282 | up(&shm_ids.sem); | |
283 | ||
284 | return err; | |
285 | } | |
286 | ||
287 | static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version) | |
288 | { | |
289 | switch(version) { | |
290 | case IPC_64: | |
291 | return copy_to_user(buf, in, sizeof(*in)); | |
292 | case IPC_OLD: | |
293 | { | |
294 | struct shmid_ds out; | |
295 | ||
296 | ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm); | |
297 | out.shm_segsz = in->shm_segsz; | |
298 | out.shm_atime = in->shm_atime; | |
299 | out.shm_dtime = in->shm_dtime; | |
300 | out.shm_ctime = in->shm_ctime; | |
301 | out.shm_cpid = in->shm_cpid; | |
302 | out.shm_lpid = in->shm_lpid; | |
303 | out.shm_nattch = in->shm_nattch; | |
304 | ||
305 | return copy_to_user(buf, &out, sizeof(out)); | |
306 | } | |
307 | default: | |
308 | return -EINVAL; | |
309 | } | |
310 | } | |
311 | ||
312 | struct shm_setbuf { | |
313 | uid_t uid; | |
314 | gid_t gid; | |
315 | mode_t mode; | |
316 | }; | |
317 | ||
318 | static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version) | |
319 | { | |
320 | switch(version) { | |
321 | case IPC_64: | |
322 | { | |
323 | struct shmid64_ds tbuf; | |
324 | ||
325 | if (copy_from_user(&tbuf, buf, sizeof(tbuf))) | |
326 | return -EFAULT; | |
327 | ||
328 | out->uid = tbuf.shm_perm.uid; | |
329 | out->gid = tbuf.shm_perm.gid; | |
330 | out->mode = tbuf.shm_flags; | |
331 | ||
332 | return 0; | |
333 | } | |
334 | case IPC_OLD: | |
335 | { | |
336 | struct shmid_ds tbuf_old; | |
337 | ||
338 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) | |
339 | return -EFAULT; | |
340 | ||
341 | out->uid = tbuf_old.shm_perm.uid; | |
342 | out->gid = tbuf_old.shm_perm.gid; | |
343 | out->mode = tbuf_old.shm_flags; | |
344 | ||
345 | return 0; | |
346 | } | |
347 | default: | |
348 | return -EINVAL; | |
349 | } | |
350 | } | |
351 | ||
352 | static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version) | |
353 | { | |
354 | switch(version) { | |
355 | case IPC_64: | |
356 | return copy_to_user(buf, in, sizeof(*in)); | |
357 | case IPC_OLD: | |
358 | { | |
359 | struct shminfo out; | |
360 | ||
361 | if(in->shmmax > INT_MAX) | |
362 | out.shmmax = INT_MAX; | |
363 | else | |
364 | out.shmmax = (int)in->shmmax; | |
365 | ||
366 | out.shmmin = in->shmmin; | |
367 | out.shmmni = in->shmmni; | |
368 | out.shmseg = in->shmseg; | |
369 | out.shmall = in->shmall; | |
370 | ||
371 | return copy_to_user(buf, &out, sizeof(out)); | |
372 | } | |
373 | default: | |
374 | return -EINVAL; | |
375 | } | |
376 | } | |
377 | ||
378 | static void shm_get_stat(unsigned long *rss, unsigned long *swp) | |
379 | { | |
380 | int i; | |
381 | ||
382 | *rss = 0; | |
383 | *swp = 0; | |
384 | ||
385 | for (i = 0; i <= shm_ids.max_id; i++) { | |
386 | struct shmid_kernel *shp; | |
387 | struct inode *inode; | |
388 | ||
389 | shp = shm_get(i); | |
390 | if(!shp) | |
391 | continue; | |
392 | ||
393 | inode = shp->shm_file->f_dentry->d_inode; | |
394 | ||
395 | if (is_file_hugepages(shp->shm_file)) { | |
396 | struct address_space *mapping = inode->i_mapping; | |
397 | *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages; | |
398 | } else { | |
399 | struct shmem_inode_info *info = SHMEM_I(inode); | |
400 | spin_lock(&info->lock); | |
401 | *rss += inode->i_mapping->nrpages; | |
402 | *swp += info->swapped; | |
403 | spin_unlock(&info->lock); | |
404 | } | |
405 | } | |
406 | } | |
407 | ||
408 | asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf) | |
409 | { | |
410 | struct shm_setbuf setbuf; | |
411 | struct shmid_kernel *shp; | |
412 | int err, version; | |
413 | ||
414 | if (cmd < 0 || shmid < 0) { | |
415 | err = -EINVAL; | |
416 | goto out; | |
417 | } | |
418 | ||
419 | version = ipc_parse_version(&cmd); | |
420 | ||
421 | switch (cmd) { /* replace with proc interface ? */ | |
422 | case IPC_INFO: | |
423 | { | |
424 | struct shminfo64 shminfo; | |
425 | ||
426 | err = security_shm_shmctl(NULL, cmd); | |
427 | if (err) | |
428 | return err; | |
429 | ||
430 | memset(&shminfo,0,sizeof(shminfo)); | |
431 | shminfo.shmmni = shminfo.shmseg = shm_ctlmni; | |
432 | shminfo.shmmax = shm_ctlmax; | |
433 | shminfo.shmall = shm_ctlall; | |
434 | ||
435 | shminfo.shmmin = SHMMIN; | |
436 | if(copy_shminfo_to_user (buf, &shminfo, version)) | |
437 | return -EFAULT; | |
438 | /* reading a integer is always atomic */ | |
439 | err= shm_ids.max_id; | |
440 | if(err<0) | |
441 | err = 0; | |
442 | goto out; | |
443 | } | |
444 | case SHM_INFO: | |
445 | { | |
446 | struct shm_info shm_info; | |
447 | ||
448 | err = security_shm_shmctl(NULL, cmd); | |
449 | if (err) | |
450 | return err; | |
451 | ||
452 | memset(&shm_info,0,sizeof(shm_info)); | |
453 | down(&shm_ids.sem); | |
454 | shm_info.used_ids = shm_ids.in_use; | |
455 | shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp); | |
456 | shm_info.shm_tot = shm_tot; | |
457 | shm_info.swap_attempts = 0; | |
458 | shm_info.swap_successes = 0; | |
459 | err = shm_ids.max_id; | |
460 | up(&shm_ids.sem); | |
461 | if(copy_to_user (buf, &shm_info, sizeof(shm_info))) { | |
462 | err = -EFAULT; | |
463 | goto out; | |
464 | } | |
465 | ||
466 | err = err < 0 ? 0 : err; | |
467 | goto out; | |
468 | } | |
469 | case SHM_STAT: | |
470 | case IPC_STAT: | |
471 | { | |
472 | struct shmid64_ds tbuf; | |
473 | int result; | |
474 | memset(&tbuf, 0, sizeof(tbuf)); | |
475 | shp = shm_lock(shmid); | |
476 | if(shp==NULL) { | |
477 | err = -EINVAL; | |
478 | goto out; | |
479 | } else if(cmd==SHM_STAT) { | |
480 | err = -EINVAL; | |
481 | if (shmid > shm_ids.max_id) | |
482 | goto out_unlock; | |
483 | result = shm_buildid(shmid, shp->shm_perm.seq); | |
484 | } else { | |
485 | err = shm_checkid(shp,shmid); | |
486 | if(err) | |
487 | goto out_unlock; | |
488 | result = 0; | |
489 | } | |
490 | err=-EACCES; | |
491 | if (ipcperms (&shp->shm_perm, S_IRUGO)) | |
492 | goto out_unlock; | |
493 | err = security_shm_shmctl(shp, cmd); | |
494 | if (err) | |
495 | goto out_unlock; | |
496 | kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm); | |
497 | tbuf.shm_segsz = shp->shm_segsz; | |
498 | tbuf.shm_atime = shp->shm_atim; | |
499 | tbuf.shm_dtime = shp->shm_dtim; | |
500 | tbuf.shm_ctime = shp->shm_ctim; | |
501 | tbuf.shm_cpid = shp->shm_cprid; | |
502 | tbuf.shm_lpid = shp->shm_lprid; | |
503 | if (!is_file_hugepages(shp->shm_file)) | |
504 | tbuf.shm_nattch = shp->shm_nattch; | |
505 | else | |
506 | tbuf.shm_nattch = file_count(shp->shm_file) - 1; | |
507 | shm_unlock(shp); | |
508 | if(copy_shmid_to_user (buf, &tbuf, version)) | |
509 | err = -EFAULT; | |
510 | else | |
511 | err = result; | |
512 | goto out; | |
513 | } | |
514 | case SHM_LOCK: | |
515 | case SHM_UNLOCK: | |
516 | { | |
517 | shp = shm_lock(shmid); | |
518 | if(shp==NULL) { | |
519 | err = -EINVAL; | |
520 | goto out; | |
521 | } | |
522 | err = shm_checkid(shp,shmid); | |
523 | if(err) | |
524 | goto out_unlock; | |
525 | ||
526 | if (!capable(CAP_IPC_LOCK)) { | |
527 | err = -EPERM; | |
528 | if (current->euid != shp->shm_perm.uid && | |
529 | current->euid != shp->shm_perm.cuid) | |
530 | goto out_unlock; | |
531 | if (cmd == SHM_LOCK && | |
532 | !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur) | |
533 | goto out_unlock; | |
534 | } | |
535 | ||
536 | err = security_shm_shmctl(shp, cmd); | |
537 | if (err) | |
538 | goto out_unlock; | |
539 | ||
540 | if(cmd==SHM_LOCK) { | |
541 | struct user_struct * user = current->user; | |
542 | if (!is_file_hugepages(shp->shm_file)) { | |
543 | err = shmem_lock(shp->shm_file, 1, user); | |
544 | if (!err) { | |
545 | shp->shm_flags |= SHM_LOCKED; | |
546 | shp->mlock_user = user; | |
547 | } | |
548 | } | |
549 | } else if (!is_file_hugepages(shp->shm_file)) { | |
550 | shmem_lock(shp->shm_file, 0, shp->mlock_user); | |
551 | shp->shm_flags &= ~SHM_LOCKED; | |
552 | shp->mlock_user = NULL; | |
553 | } | |
554 | shm_unlock(shp); | |
555 | goto out; | |
556 | } | |
557 | case IPC_RMID: | |
558 | { | |
559 | /* | |
560 | * We cannot simply remove the file. The SVID states | |
561 | * that the block remains until the last person | |
562 | * detaches from it, then is deleted. A shmat() on | |
563 | * an RMID segment is legal in older Linux and if | |
564 | * we change it apps break... | |
565 | * | |
566 | * Instead we set a destroyed flag, and then blow | |
567 | * the name away when the usage hits zero. | |
568 | */ | |
569 | down(&shm_ids.sem); | |
570 | shp = shm_lock(shmid); | |
571 | err = -EINVAL; | |
572 | if (shp == NULL) | |
573 | goto out_up; | |
574 | err = shm_checkid(shp, shmid); | |
575 | if(err) | |
576 | goto out_unlock_up; | |
577 | ||
578 | if (current->euid != shp->shm_perm.uid && | |
579 | current->euid != shp->shm_perm.cuid && | |
580 | !capable(CAP_SYS_ADMIN)) { | |
581 | err=-EPERM; | |
582 | goto out_unlock_up; | |
583 | } | |
584 | ||
585 | err = security_shm_shmctl(shp, cmd); | |
586 | if (err) | |
587 | goto out_unlock_up; | |
588 | ||
589 | if (shp->shm_nattch){ | |
590 | shp->shm_flags |= SHM_DEST; | |
591 | /* Do not find it any more */ | |
592 | shp->shm_perm.key = IPC_PRIVATE; | |
593 | shm_unlock(shp); | |
594 | } else | |
595 | shm_destroy (shp); | |
596 | up(&shm_ids.sem); | |
597 | goto out; | |
598 | } | |
599 | ||
600 | case IPC_SET: | |
601 | { | |
602 | if (copy_shmid_from_user (&setbuf, buf, version)) { | |
603 | err = -EFAULT; | |
604 | goto out; | |
605 | } | |
606 | if ((err = audit_ipc_perms(0, setbuf.uid, setbuf.gid, setbuf.mode))) | |
607 | return err; | |
608 | down(&shm_ids.sem); | |
609 | shp = shm_lock(shmid); | |
610 | err=-EINVAL; | |
611 | if(shp==NULL) | |
612 | goto out_up; | |
613 | err = shm_checkid(shp,shmid); | |
614 | if(err) | |
615 | goto out_unlock_up; | |
616 | err=-EPERM; | |
617 | if (current->euid != shp->shm_perm.uid && | |
618 | current->euid != shp->shm_perm.cuid && | |
619 | !capable(CAP_SYS_ADMIN)) { | |
620 | goto out_unlock_up; | |
621 | } | |
622 | ||
623 | err = security_shm_shmctl(shp, cmd); | |
624 | if (err) | |
625 | goto out_unlock_up; | |
626 | ||
627 | shp->shm_perm.uid = setbuf.uid; | |
628 | shp->shm_perm.gid = setbuf.gid; | |
629 | shp->shm_flags = (shp->shm_flags & ~S_IRWXUGO) | |
630 | | (setbuf.mode & S_IRWXUGO); | |
631 | shp->shm_ctim = get_seconds(); | |
632 | break; | |
633 | } | |
634 | ||
635 | default: | |
636 | err = -EINVAL; | |
637 | goto out; | |
638 | } | |
639 | ||
640 | err = 0; | |
641 | out_unlock_up: | |
642 | shm_unlock(shp); | |
643 | out_up: | |
644 | up(&shm_ids.sem); | |
645 | goto out; | |
646 | out_unlock: | |
647 | shm_unlock(shp); | |
648 | out: | |
649 | return err; | |
650 | } | |
651 | ||
652 | /* | |
653 | * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists. | |
654 | * | |
655 | * NOTE! Despite the name, this is NOT a direct system call entrypoint. The | |
656 | * "raddr" thing points to kernel space, and there has to be a wrapper around | |
657 | * this. | |
658 | */ | |
659 | long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr) | |
660 | { | |
661 | struct shmid_kernel *shp; | |
662 | unsigned long addr; | |
663 | unsigned long size; | |
664 | struct file * file; | |
665 | int err; | |
666 | unsigned long flags; | |
667 | unsigned long prot; | |
668 | unsigned long o_flags; | |
669 | int acc_mode; | |
670 | void *user_addr; | |
671 | ||
672 | if (shmid < 0) { | |
673 | err = -EINVAL; | |
674 | goto out; | |
675 | } else if ((addr = (ulong)shmaddr)) { | |
676 | if (addr & (SHMLBA-1)) { | |
677 | if (shmflg & SHM_RND) | |
678 | addr &= ~(SHMLBA-1); /* round down */ | |
679 | else | |
680 | #ifndef __ARCH_FORCE_SHMLBA | |
681 | if (addr & ~PAGE_MASK) | |
682 | #endif | |
683 | return -EINVAL; | |
684 | } | |
685 | flags = MAP_SHARED | MAP_FIXED; | |
686 | } else { | |
687 | if ((shmflg & SHM_REMAP)) | |
688 | return -EINVAL; | |
689 | ||
690 | flags = MAP_SHARED; | |
691 | } | |
692 | ||
693 | if (shmflg & SHM_RDONLY) { | |
694 | prot = PROT_READ; | |
695 | o_flags = O_RDONLY; | |
696 | acc_mode = S_IRUGO; | |
697 | } else { | |
698 | prot = PROT_READ | PROT_WRITE; | |
699 | o_flags = O_RDWR; | |
700 | acc_mode = S_IRUGO | S_IWUGO; | |
701 | } | |
702 | if (shmflg & SHM_EXEC) { | |
703 | prot |= PROT_EXEC; | |
704 | acc_mode |= S_IXUGO; | |
705 | } | |
706 | ||
707 | /* | |
708 | * We cannot rely on the fs check since SYSV IPC does have an | |
709 | * additional creator id... | |
710 | */ | |
711 | shp = shm_lock(shmid); | |
712 | if(shp == NULL) { | |
713 | err = -EINVAL; | |
714 | goto out; | |
715 | } | |
716 | err = shm_checkid(shp,shmid); | |
717 | if (err) { | |
718 | shm_unlock(shp); | |
719 | goto out; | |
720 | } | |
721 | if (ipcperms(&shp->shm_perm, acc_mode)) { | |
722 | shm_unlock(shp); | |
723 | err = -EACCES; | |
724 | goto out; | |
725 | } | |
726 | ||
727 | err = security_shm_shmat(shp, shmaddr, shmflg); | |
728 | if (err) { | |
729 | shm_unlock(shp); | |
730 | return err; | |
731 | } | |
732 | ||
733 | file = shp->shm_file; | |
734 | size = i_size_read(file->f_dentry->d_inode); | |
735 | shp->shm_nattch++; | |
736 | shm_unlock(shp); | |
737 | ||
738 | down_write(¤t->mm->mmap_sem); | |
739 | if (addr && !(shmflg & SHM_REMAP)) { | |
740 | user_addr = ERR_PTR(-EINVAL); | |
741 | if (find_vma_intersection(current->mm, addr, addr + size)) | |
742 | goto invalid; | |
743 | /* | |
744 | * If shm segment goes below stack, make sure there is some | |
745 | * space left for the stack to grow (at least 4 pages). | |
746 | */ | |
747 | if (addr < current->mm->start_stack && | |
748 | addr > current->mm->start_stack - size - PAGE_SIZE * 5) | |
749 | goto invalid; | |
750 | } | |
751 | ||
752 | user_addr = (void*) do_mmap (file, addr, size, prot, flags, 0); | |
753 | ||
754 | invalid: | |
755 | up_write(¤t->mm->mmap_sem); | |
756 | ||
757 | down (&shm_ids.sem); | |
758 | if(!(shp = shm_lock(shmid))) | |
759 | BUG(); | |
760 | shp->shm_nattch--; | |
761 | if(shp->shm_nattch == 0 && | |
762 | shp->shm_flags & SHM_DEST) | |
763 | shm_destroy (shp); | |
764 | else | |
765 | shm_unlock(shp); | |
766 | up (&shm_ids.sem); | |
767 | ||
768 | *raddr = (unsigned long) user_addr; | |
769 | err = 0; | |
770 | if (IS_ERR(user_addr)) | |
771 | err = PTR_ERR(user_addr); | |
772 | out: | |
773 | return err; | |
774 | } | |
775 | ||
7d87e14c SR |
776 | asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg) |
777 | { | |
778 | unsigned long ret; | |
779 | long err; | |
780 | ||
781 | err = do_shmat(shmid, shmaddr, shmflg, &ret); | |
782 | if (err) | |
783 | return err; | |
784 | force_successful_syscall_return(); | |
785 | return (long)ret; | |
786 | } | |
787 | ||
1da177e4 LT |
788 | /* |
789 | * detach and kill segment if marked destroyed. | |
790 | * The work is done in shm_close. | |
791 | */ | |
792 | asmlinkage long sys_shmdt(char __user *shmaddr) | |
793 | { | |
794 | struct mm_struct *mm = current->mm; | |
795 | struct vm_area_struct *vma, *next; | |
796 | unsigned long addr = (unsigned long)shmaddr; | |
797 | loff_t size = 0; | |
798 | int retval = -EINVAL; | |
799 | ||
800 | down_write(&mm->mmap_sem); | |
801 | ||
802 | /* | |
803 | * This function tries to be smart and unmap shm segments that | |
804 | * were modified by partial mlock or munmap calls: | |
805 | * - It first determines the size of the shm segment that should be | |
806 | * unmapped: It searches for a vma that is backed by shm and that | |
807 | * started at address shmaddr. It records it's size and then unmaps | |
808 | * it. | |
809 | * - Then it unmaps all shm vmas that started at shmaddr and that | |
810 | * are within the initially determined size. | |
811 | * Errors from do_munmap are ignored: the function only fails if | |
812 | * it's called with invalid parameters or if it's called to unmap | |
813 | * a part of a vma. Both calls in this function are for full vmas, | |
814 | * the parameters are directly copied from the vma itself and always | |
815 | * valid - therefore do_munmap cannot fail. (famous last words?) | |
816 | */ | |
817 | /* | |
818 | * If it had been mremap()'d, the starting address would not | |
819 | * match the usual checks anyway. So assume all vma's are | |
820 | * above the starting address given. | |
821 | */ | |
822 | vma = find_vma(mm, addr); | |
823 | ||
824 | while (vma) { | |
825 | next = vma->vm_next; | |
826 | ||
827 | /* | |
828 | * Check if the starting address would match, i.e. it's | |
829 | * a fragment created by mprotect() and/or munmap(), or it | |
830 | * otherwise it starts at this address with no hassles. | |
831 | */ | |
832 | if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) && | |
833 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) { | |
834 | ||
835 | ||
836 | size = vma->vm_file->f_dentry->d_inode->i_size; | |
837 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); | |
838 | /* | |
839 | * We discovered the size of the shm segment, so | |
840 | * break out of here and fall through to the next | |
841 | * loop that uses the size information to stop | |
842 | * searching for matching vma's. | |
843 | */ | |
844 | retval = 0; | |
845 | vma = next; | |
846 | break; | |
847 | } | |
848 | vma = next; | |
849 | } | |
850 | ||
851 | /* | |
852 | * We need look no further than the maximum address a fragment | |
853 | * could possibly have landed at. Also cast things to loff_t to | |
854 | * prevent overflows and make comparisions vs. equal-width types. | |
855 | */ | |
856 | while (vma && (loff_t)(vma->vm_end - addr) <= size) { | |
857 | next = vma->vm_next; | |
858 | ||
859 | /* finding a matching vma now does not alter retval */ | |
860 | if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) && | |
861 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) | |
862 | ||
863 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); | |
864 | vma = next; | |
865 | } | |
866 | ||
867 | up_write(&mm->mmap_sem); | |
868 | return retval; | |
869 | } | |
870 | ||
871 | #ifdef CONFIG_PROC_FS | |
872 | static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data) | |
873 | { | |
874 | off_t pos = 0; | |
875 | off_t begin = 0; | |
876 | int i, len = 0; | |
877 | ||
878 | down(&shm_ids.sem); | |
879 | len += sprintf(buffer, " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n"); | |
880 | ||
881 | for(i = 0; i <= shm_ids.max_id; i++) { | |
882 | struct shmid_kernel* shp; | |
883 | ||
884 | shp = shm_lock(i); | |
885 | if(shp!=NULL) { | |
886 | #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n" | |
887 | #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n" | |
888 | char *format; | |
889 | ||
890 | if (sizeof(size_t) <= sizeof(int)) | |
891 | format = SMALL_STRING; | |
892 | else | |
893 | format = BIG_STRING; | |
894 | len += sprintf(buffer + len, format, | |
895 | shp->shm_perm.key, | |
896 | shm_buildid(i, shp->shm_perm.seq), | |
897 | shp->shm_flags, | |
898 | shp->shm_segsz, | |
899 | shp->shm_cprid, | |
900 | shp->shm_lprid, | |
901 | is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch, | |
902 | shp->shm_perm.uid, | |
903 | shp->shm_perm.gid, | |
904 | shp->shm_perm.cuid, | |
905 | shp->shm_perm.cgid, | |
906 | shp->shm_atim, | |
907 | shp->shm_dtim, | |
908 | shp->shm_ctim); | |
909 | shm_unlock(shp); | |
910 | ||
911 | pos += len; | |
912 | if(pos < offset) { | |
913 | len = 0; | |
914 | begin = pos; | |
915 | } | |
916 | if(pos > offset + length) | |
917 | goto done; | |
918 | } | |
919 | } | |
920 | *eof = 1; | |
921 | done: | |
922 | up(&shm_ids.sem); | |
923 | *start = buffer + (offset - begin); | |
924 | len -= (offset - begin); | |
925 | if(len > length) | |
926 | len = length; | |
927 | if(len < 0) | |
928 | len = 0; | |
929 | return len; | |
930 | } | |
931 | #endif |