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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> | |
1da177e4 LT |
26 | #include <linux/shmem_fs.h> |
27 | #include <linux/security.h> | |
28 | #include <linux/syscalls.h> | |
29 | #include <linux/audit.h> | |
7d87e14c | 30 | #include <linux/ptrace.h> |
19b4946c | 31 | #include <linux/seq_file.h> |
7d87e14c | 32 | |
1da177e4 LT |
33 | #include <asm/uaccess.h> |
34 | ||
35 | #include "util.h" | |
36 | ||
1da177e4 LT |
37 | static struct file_operations shm_file_operations; |
38 | static struct vm_operations_struct shm_vm_ops; | |
39 | ||
40 | static struct ipc_ids shm_ids; | |
41 | ||
42 | #define shm_lock(id) ((struct shmid_kernel*)ipc_lock(&shm_ids,id)) | |
43 | #define shm_unlock(shp) ipc_unlock(&(shp)->shm_perm) | |
44 | #define shm_get(id) ((struct shmid_kernel*)ipc_get(&shm_ids,id)) | |
45 | #define shm_buildid(id, seq) \ | |
46 | ipc_buildid(&shm_ids, id, seq) | |
47 | ||
48 | static int newseg (key_t key, int shmflg, size_t size); | |
49 | static void shm_open (struct vm_area_struct *shmd); | |
50 | static void shm_close (struct vm_area_struct *shmd); | |
51 | #ifdef CONFIG_PROC_FS | |
19b4946c | 52 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it); |
1da177e4 LT |
53 | #endif |
54 | ||
55 | size_t shm_ctlmax = SHMMAX; | |
56 | size_t shm_ctlall = SHMALL; | |
57 | int shm_ctlmni = SHMMNI; | |
58 | ||
59 | static int shm_tot; /* total number of shared memory pages */ | |
60 | ||
61 | void __init shm_init (void) | |
62 | { | |
63 | ipc_init_ids(&shm_ids, 1); | |
19b4946c MW |
64 | ipc_init_proc_interface("sysvipc/shm", |
65 | " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n", | |
66 | &shm_ids, | |
67 | sysvipc_shm_proc_show); | |
1da177e4 LT |
68 | } |
69 | ||
70 | static inline int shm_checkid(struct shmid_kernel *s, int id) | |
71 | { | |
72 | if (ipc_checkid(&shm_ids,&s->shm_perm,id)) | |
73 | return -EIDRM; | |
74 | return 0; | |
75 | } | |
76 | ||
77 | static inline struct shmid_kernel *shm_rmid(int id) | |
78 | { | |
79 | return (struct shmid_kernel *)ipc_rmid(&shm_ids,id); | |
80 | } | |
81 | ||
82 | static inline int shm_addid(struct shmid_kernel *shp) | |
83 | { | |
84 | return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni); | |
85 | } | |
86 | ||
87 | ||
88 | ||
89 | static inline void shm_inc (int id) { | |
90 | struct shmid_kernel *shp; | |
91 | ||
92 | if(!(shp = shm_lock(id))) | |
93 | BUG(); | |
94 | shp->shm_atim = get_seconds(); | |
95 | shp->shm_lprid = current->tgid; | |
96 | shp->shm_nattch++; | |
97 | shm_unlock(shp); | |
98 | } | |
99 | ||
100 | /* This is called by fork, once for every shm attach. */ | |
101 | static void shm_open (struct vm_area_struct *shmd) | |
102 | { | |
103 | shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino); | |
104 | } | |
105 | ||
106 | /* | |
107 | * shm_destroy - free the struct shmid_kernel | |
108 | * | |
109 | * @shp: struct to free | |
110 | * | |
111 | * It has to be called with shp and shm_ids.sem locked, | |
112 | * but returns with shp unlocked and freed. | |
113 | */ | |
114 | static void shm_destroy (struct shmid_kernel *shp) | |
115 | { | |
116 | shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
117 | shm_rmid (shp->id); | |
118 | shm_unlock(shp); | |
119 | if (!is_file_hugepages(shp->shm_file)) | |
120 | shmem_lock(shp->shm_file, 0, shp->mlock_user); | |
121 | else | |
122 | user_shm_unlock(shp->shm_file->f_dentry->d_inode->i_size, | |
123 | shp->mlock_user); | |
124 | fput (shp->shm_file); | |
125 | security_shm_free(shp); | |
126 | ipc_rcu_putref(shp); | |
127 | } | |
128 | ||
129 | /* | |
130 | * remove the attach descriptor shmd. | |
131 | * free memory for segment if it is marked destroyed. | |
132 | * The descriptor has already been removed from the current->mm->mmap list | |
133 | * and will later be kfree()d. | |
134 | */ | |
135 | static void shm_close (struct vm_area_struct *shmd) | |
136 | { | |
137 | struct file * file = shmd->vm_file; | |
138 | int id = file->f_dentry->d_inode->i_ino; | |
139 | struct shmid_kernel *shp; | |
140 | ||
141 | down (&shm_ids.sem); | |
142 | /* remove from the list of attaches of the shm segment */ | |
143 | if(!(shp = shm_lock(id))) | |
144 | BUG(); | |
145 | shp->shm_lprid = current->tgid; | |
146 | shp->shm_dtim = get_seconds(); | |
147 | shp->shm_nattch--; | |
148 | if(shp->shm_nattch == 0 && | |
b33291c0 | 149 | shp->shm_perm.mode & SHM_DEST) |
1da177e4 LT |
150 | shm_destroy (shp); |
151 | else | |
152 | shm_unlock(shp); | |
153 | up (&shm_ids.sem); | |
154 | } | |
155 | ||
156 | static int shm_mmap(struct file * file, struct vm_area_struct * vma) | |
157 | { | |
b0e15190 DH |
158 | int ret; |
159 | ||
160 | ret = shmem_mmap(file, vma); | |
161 | if (ret == 0) { | |
162 | vma->vm_ops = &shm_vm_ops; | |
163 | shm_inc(file->f_dentry->d_inode->i_ino); | |
164 | } | |
165 | ||
166 | return ret; | |
1da177e4 LT |
167 | } |
168 | ||
169 | static struct file_operations shm_file_operations = { | |
b0e15190 DH |
170 | .mmap = shm_mmap, |
171 | #ifndef CONFIG_MMU | |
172 | .get_unmapped_area = shmem_get_unmapped_area, | |
173 | #endif | |
1da177e4 LT |
174 | }; |
175 | ||
176 | static struct vm_operations_struct shm_vm_ops = { | |
177 | .open = shm_open, /* callback for a new vm-area open */ | |
178 | .close = shm_close, /* callback for when the vm-area is released */ | |
179 | .nopage = shmem_nopage, | |
6ade43fb | 180 | #if defined(CONFIG_NUMA) && defined(CONFIG_SHMEM) |
1da177e4 LT |
181 | .set_policy = shmem_set_policy, |
182 | .get_policy = shmem_get_policy, | |
183 | #endif | |
184 | }; | |
185 | ||
186 | static int newseg (key_t key, int shmflg, size_t size) | |
187 | { | |
188 | int error; | |
189 | struct shmid_kernel *shp; | |
190 | int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT; | |
191 | struct file * file; | |
192 | char name[13]; | |
193 | int id; | |
194 | ||
195 | if (size < SHMMIN || size > shm_ctlmax) | |
196 | return -EINVAL; | |
197 | ||
198 | if (shm_tot + numpages >= shm_ctlall) | |
199 | return -ENOSPC; | |
200 | ||
201 | shp = ipc_rcu_alloc(sizeof(*shp)); | |
202 | if (!shp) | |
203 | return -ENOMEM; | |
204 | ||
205 | shp->shm_perm.key = key; | |
b33291c0 | 206 | shp->shm_perm.mode = (shmflg & S_IRWXUGO); |
1da177e4 LT |
207 | shp->mlock_user = NULL; |
208 | ||
209 | shp->shm_perm.security = NULL; | |
210 | error = security_shm_alloc(shp); | |
211 | if (error) { | |
212 | ipc_rcu_putref(shp); | |
213 | return error; | |
214 | } | |
215 | ||
216 | if (shmflg & SHM_HUGETLB) { | |
217 | /* hugetlb_zero_setup takes care of mlock user accounting */ | |
218 | file = hugetlb_zero_setup(size); | |
219 | shp->mlock_user = current->user; | |
220 | } else { | |
bf8f972d BP |
221 | int acctflag = VM_ACCOUNT; |
222 | /* | |
223 | * Do not allow no accounting for OVERCOMMIT_NEVER, even | |
224 | * if it's asked for. | |
225 | */ | |
226 | if ((shmflg & SHM_NORESERVE) && | |
227 | sysctl_overcommit_memory != OVERCOMMIT_NEVER) | |
228 | acctflag = 0; | |
1da177e4 | 229 | sprintf (name, "SYSV%08x", key); |
bf8f972d | 230 | file = shmem_file_setup(name, size, acctflag); |
1da177e4 LT |
231 | } |
232 | error = PTR_ERR(file); | |
233 | if (IS_ERR(file)) | |
234 | goto no_file; | |
235 | ||
236 | error = -ENOSPC; | |
237 | id = shm_addid(shp); | |
238 | if(id == -1) | |
239 | goto no_id; | |
240 | ||
241 | shp->shm_cprid = current->tgid; | |
242 | shp->shm_lprid = 0; | |
243 | shp->shm_atim = shp->shm_dtim = 0; | |
244 | shp->shm_ctim = get_seconds(); | |
245 | shp->shm_segsz = size; | |
246 | shp->shm_nattch = 0; | |
247 | shp->id = shm_buildid(id,shp->shm_perm.seq); | |
248 | shp->shm_file = file; | |
249 | file->f_dentry->d_inode->i_ino = shp->id; | |
551110a9 K |
250 | |
251 | /* Hugetlb ops would have already been assigned. */ | |
252 | if (!(shmflg & SHM_HUGETLB)) | |
1da177e4 | 253 | file->f_op = &shm_file_operations; |
551110a9 | 254 | |
1da177e4 LT |
255 | shm_tot += numpages; |
256 | shm_unlock(shp); | |
257 | return shp->id; | |
258 | ||
259 | no_id: | |
260 | fput(file); | |
261 | no_file: | |
262 | security_shm_free(shp); | |
263 | ipc_rcu_putref(shp); | |
264 | return error; | |
265 | } | |
266 | ||
267 | asmlinkage long sys_shmget (key_t key, size_t size, int shmflg) | |
268 | { | |
269 | struct shmid_kernel *shp; | |
270 | int err, id = 0; | |
271 | ||
272 | down(&shm_ids.sem); | |
273 | if (key == IPC_PRIVATE) { | |
274 | err = newseg(key, shmflg, size); | |
275 | } else if ((id = ipc_findkey(&shm_ids, key)) == -1) { | |
276 | if (!(shmflg & IPC_CREAT)) | |
277 | err = -ENOENT; | |
278 | else | |
279 | err = newseg(key, shmflg, size); | |
280 | } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) { | |
281 | err = -EEXIST; | |
282 | } else { | |
283 | shp = shm_lock(id); | |
284 | if(shp==NULL) | |
285 | BUG(); | |
286 | if (shp->shm_segsz < size) | |
287 | err = -EINVAL; | |
288 | else if (ipcperms(&shp->shm_perm, shmflg)) | |
289 | err = -EACCES; | |
290 | else { | |
291 | int shmid = shm_buildid(id, shp->shm_perm.seq); | |
292 | err = security_shm_associate(shp, shmflg); | |
293 | if (!err) | |
294 | err = shmid; | |
295 | } | |
296 | shm_unlock(shp); | |
297 | } | |
298 | up(&shm_ids.sem); | |
299 | ||
300 | return err; | |
301 | } | |
302 | ||
303 | static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version) | |
304 | { | |
305 | switch(version) { | |
306 | case IPC_64: | |
307 | return copy_to_user(buf, in, sizeof(*in)); | |
308 | case IPC_OLD: | |
309 | { | |
310 | struct shmid_ds out; | |
311 | ||
312 | ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm); | |
313 | out.shm_segsz = in->shm_segsz; | |
314 | out.shm_atime = in->shm_atime; | |
315 | out.shm_dtime = in->shm_dtime; | |
316 | out.shm_ctime = in->shm_ctime; | |
317 | out.shm_cpid = in->shm_cpid; | |
318 | out.shm_lpid = in->shm_lpid; | |
319 | out.shm_nattch = in->shm_nattch; | |
320 | ||
321 | return copy_to_user(buf, &out, sizeof(out)); | |
322 | } | |
323 | default: | |
324 | return -EINVAL; | |
325 | } | |
326 | } | |
327 | ||
328 | struct shm_setbuf { | |
329 | uid_t uid; | |
330 | gid_t gid; | |
331 | mode_t mode; | |
332 | }; | |
333 | ||
334 | static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version) | |
335 | { | |
336 | switch(version) { | |
337 | case IPC_64: | |
338 | { | |
339 | struct shmid64_ds tbuf; | |
340 | ||
341 | if (copy_from_user(&tbuf, buf, sizeof(tbuf))) | |
342 | return -EFAULT; | |
343 | ||
344 | out->uid = tbuf.shm_perm.uid; | |
345 | out->gid = tbuf.shm_perm.gid; | |
b33291c0 | 346 | out->mode = tbuf.shm_perm.mode; |
1da177e4 LT |
347 | |
348 | return 0; | |
349 | } | |
350 | case IPC_OLD: | |
351 | { | |
352 | struct shmid_ds tbuf_old; | |
353 | ||
354 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) | |
355 | return -EFAULT; | |
356 | ||
357 | out->uid = tbuf_old.shm_perm.uid; | |
358 | out->gid = tbuf_old.shm_perm.gid; | |
b33291c0 | 359 | out->mode = tbuf_old.shm_perm.mode; |
1da177e4 LT |
360 | |
361 | return 0; | |
362 | } | |
363 | default: | |
364 | return -EINVAL; | |
365 | } | |
366 | } | |
367 | ||
368 | static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version) | |
369 | { | |
370 | switch(version) { | |
371 | case IPC_64: | |
372 | return copy_to_user(buf, in, sizeof(*in)); | |
373 | case IPC_OLD: | |
374 | { | |
375 | struct shminfo out; | |
376 | ||
377 | if(in->shmmax > INT_MAX) | |
378 | out.shmmax = INT_MAX; | |
379 | else | |
380 | out.shmmax = (int)in->shmmax; | |
381 | ||
382 | out.shmmin = in->shmmin; | |
383 | out.shmmni = in->shmmni; | |
384 | out.shmseg = in->shmseg; | |
385 | out.shmall = in->shmall; | |
386 | ||
387 | return copy_to_user(buf, &out, sizeof(out)); | |
388 | } | |
389 | default: | |
390 | return -EINVAL; | |
391 | } | |
392 | } | |
393 | ||
394 | static void shm_get_stat(unsigned long *rss, unsigned long *swp) | |
395 | { | |
396 | int i; | |
397 | ||
398 | *rss = 0; | |
399 | *swp = 0; | |
400 | ||
401 | for (i = 0; i <= shm_ids.max_id; i++) { | |
402 | struct shmid_kernel *shp; | |
403 | struct inode *inode; | |
404 | ||
405 | shp = shm_get(i); | |
406 | if(!shp) | |
407 | continue; | |
408 | ||
409 | inode = shp->shm_file->f_dentry->d_inode; | |
410 | ||
411 | if (is_file_hugepages(shp->shm_file)) { | |
412 | struct address_space *mapping = inode->i_mapping; | |
413 | *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages; | |
414 | } else { | |
415 | struct shmem_inode_info *info = SHMEM_I(inode); | |
416 | spin_lock(&info->lock); | |
417 | *rss += inode->i_mapping->nrpages; | |
418 | *swp += info->swapped; | |
419 | spin_unlock(&info->lock); | |
420 | } | |
421 | } | |
422 | } | |
423 | ||
424 | asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf) | |
425 | { | |
426 | struct shm_setbuf setbuf; | |
427 | struct shmid_kernel *shp; | |
428 | int err, version; | |
429 | ||
430 | if (cmd < 0 || shmid < 0) { | |
431 | err = -EINVAL; | |
432 | goto out; | |
433 | } | |
434 | ||
435 | version = ipc_parse_version(&cmd); | |
436 | ||
437 | switch (cmd) { /* replace with proc interface ? */ | |
438 | case IPC_INFO: | |
439 | { | |
440 | struct shminfo64 shminfo; | |
441 | ||
442 | err = security_shm_shmctl(NULL, cmd); | |
443 | if (err) | |
444 | return err; | |
445 | ||
446 | memset(&shminfo,0,sizeof(shminfo)); | |
447 | shminfo.shmmni = shminfo.shmseg = shm_ctlmni; | |
448 | shminfo.shmmax = shm_ctlmax; | |
449 | shminfo.shmall = shm_ctlall; | |
450 | ||
451 | shminfo.shmmin = SHMMIN; | |
452 | if(copy_shminfo_to_user (buf, &shminfo, version)) | |
453 | return -EFAULT; | |
454 | /* reading a integer is always atomic */ | |
455 | err= shm_ids.max_id; | |
456 | if(err<0) | |
457 | err = 0; | |
458 | goto out; | |
459 | } | |
460 | case SHM_INFO: | |
461 | { | |
462 | struct shm_info shm_info; | |
463 | ||
464 | err = security_shm_shmctl(NULL, cmd); | |
465 | if (err) | |
466 | return err; | |
467 | ||
468 | memset(&shm_info,0,sizeof(shm_info)); | |
469 | down(&shm_ids.sem); | |
470 | shm_info.used_ids = shm_ids.in_use; | |
471 | shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp); | |
472 | shm_info.shm_tot = shm_tot; | |
473 | shm_info.swap_attempts = 0; | |
474 | shm_info.swap_successes = 0; | |
475 | err = shm_ids.max_id; | |
476 | up(&shm_ids.sem); | |
477 | if(copy_to_user (buf, &shm_info, sizeof(shm_info))) { | |
478 | err = -EFAULT; | |
479 | goto out; | |
480 | } | |
481 | ||
482 | err = err < 0 ? 0 : err; | |
483 | goto out; | |
484 | } | |
485 | case SHM_STAT: | |
486 | case IPC_STAT: | |
487 | { | |
488 | struct shmid64_ds tbuf; | |
489 | int result; | |
490 | memset(&tbuf, 0, sizeof(tbuf)); | |
491 | shp = shm_lock(shmid); | |
492 | if(shp==NULL) { | |
493 | err = -EINVAL; | |
494 | goto out; | |
495 | } else if(cmd==SHM_STAT) { | |
496 | err = -EINVAL; | |
497 | if (shmid > shm_ids.max_id) | |
498 | goto out_unlock; | |
499 | result = shm_buildid(shmid, shp->shm_perm.seq); | |
500 | } else { | |
501 | err = shm_checkid(shp,shmid); | |
502 | if(err) | |
503 | goto out_unlock; | |
504 | result = 0; | |
505 | } | |
506 | err=-EACCES; | |
507 | if (ipcperms (&shp->shm_perm, S_IRUGO)) | |
508 | goto out_unlock; | |
509 | err = security_shm_shmctl(shp, cmd); | |
510 | if (err) | |
511 | goto out_unlock; | |
512 | kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm); | |
513 | tbuf.shm_segsz = shp->shm_segsz; | |
514 | tbuf.shm_atime = shp->shm_atim; | |
515 | tbuf.shm_dtime = shp->shm_dtim; | |
516 | tbuf.shm_ctime = shp->shm_ctim; | |
517 | tbuf.shm_cpid = shp->shm_cprid; | |
518 | tbuf.shm_lpid = shp->shm_lprid; | |
519 | if (!is_file_hugepages(shp->shm_file)) | |
520 | tbuf.shm_nattch = shp->shm_nattch; | |
521 | else | |
522 | tbuf.shm_nattch = file_count(shp->shm_file) - 1; | |
523 | shm_unlock(shp); | |
524 | if(copy_shmid_to_user (buf, &tbuf, version)) | |
525 | err = -EFAULT; | |
526 | else | |
527 | err = result; | |
528 | goto out; | |
529 | } | |
530 | case SHM_LOCK: | |
531 | case SHM_UNLOCK: | |
532 | { | |
533 | shp = shm_lock(shmid); | |
534 | if(shp==NULL) { | |
535 | err = -EINVAL; | |
536 | goto out; | |
537 | } | |
538 | err = shm_checkid(shp,shmid); | |
539 | if(err) | |
540 | goto out_unlock; | |
541 | ||
542 | if (!capable(CAP_IPC_LOCK)) { | |
543 | err = -EPERM; | |
544 | if (current->euid != shp->shm_perm.uid && | |
545 | current->euid != shp->shm_perm.cuid) | |
546 | goto out_unlock; | |
547 | if (cmd == SHM_LOCK && | |
548 | !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur) | |
549 | goto out_unlock; | |
550 | } | |
551 | ||
552 | err = security_shm_shmctl(shp, cmd); | |
553 | if (err) | |
554 | goto out_unlock; | |
555 | ||
556 | if(cmd==SHM_LOCK) { | |
557 | struct user_struct * user = current->user; | |
558 | if (!is_file_hugepages(shp->shm_file)) { | |
559 | err = shmem_lock(shp->shm_file, 1, user); | |
560 | if (!err) { | |
b33291c0 | 561 | shp->shm_perm.mode |= SHM_LOCKED; |
1da177e4 LT |
562 | shp->mlock_user = user; |
563 | } | |
564 | } | |
565 | } else if (!is_file_hugepages(shp->shm_file)) { | |
566 | shmem_lock(shp->shm_file, 0, shp->mlock_user); | |
b33291c0 | 567 | shp->shm_perm.mode &= ~SHM_LOCKED; |
1da177e4 LT |
568 | shp->mlock_user = NULL; |
569 | } | |
570 | shm_unlock(shp); | |
571 | goto out; | |
572 | } | |
573 | case IPC_RMID: | |
574 | { | |
575 | /* | |
576 | * We cannot simply remove the file. The SVID states | |
577 | * that the block remains until the last person | |
578 | * detaches from it, then is deleted. A shmat() on | |
579 | * an RMID segment is legal in older Linux and if | |
580 | * we change it apps break... | |
581 | * | |
582 | * Instead we set a destroyed flag, and then blow | |
583 | * the name away when the usage hits zero. | |
584 | */ | |
585 | down(&shm_ids.sem); | |
586 | shp = shm_lock(shmid); | |
587 | err = -EINVAL; | |
588 | if (shp == NULL) | |
589 | goto out_up; | |
590 | err = shm_checkid(shp, shmid); | |
591 | if(err) | |
592 | goto out_unlock_up; | |
593 | ||
594 | if (current->euid != shp->shm_perm.uid && | |
595 | current->euid != shp->shm_perm.cuid && | |
596 | !capable(CAP_SYS_ADMIN)) { | |
597 | err=-EPERM; | |
598 | goto out_unlock_up; | |
599 | } | |
600 | ||
601 | err = security_shm_shmctl(shp, cmd); | |
602 | if (err) | |
603 | goto out_unlock_up; | |
604 | ||
605 | if (shp->shm_nattch){ | |
b33291c0 | 606 | shp->shm_perm.mode |= SHM_DEST; |
1da177e4 LT |
607 | /* Do not find it any more */ |
608 | shp->shm_perm.key = IPC_PRIVATE; | |
609 | shm_unlock(shp); | |
610 | } else | |
611 | shm_destroy (shp); | |
612 | up(&shm_ids.sem); | |
613 | goto out; | |
614 | } | |
615 | ||
616 | case IPC_SET: | |
617 | { | |
618 | if (copy_shmid_from_user (&setbuf, buf, version)) { | |
619 | err = -EFAULT; | |
620 | goto out; | |
621 | } | |
622 | if ((err = audit_ipc_perms(0, setbuf.uid, setbuf.gid, setbuf.mode))) | |
623 | return err; | |
624 | down(&shm_ids.sem); | |
625 | shp = shm_lock(shmid); | |
626 | err=-EINVAL; | |
627 | if(shp==NULL) | |
628 | goto out_up; | |
629 | err = shm_checkid(shp,shmid); | |
630 | if(err) | |
631 | goto out_unlock_up; | |
632 | err=-EPERM; | |
633 | if (current->euid != shp->shm_perm.uid && | |
634 | current->euid != shp->shm_perm.cuid && | |
635 | !capable(CAP_SYS_ADMIN)) { | |
636 | goto out_unlock_up; | |
637 | } | |
638 | ||
639 | err = security_shm_shmctl(shp, cmd); | |
640 | if (err) | |
641 | goto out_unlock_up; | |
642 | ||
643 | shp->shm_perm.uid = setbuf.uid; | |
644 | shp->shm_perm.gid = setbuf.gid; | |
b33291c0 | 645 | shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO) |
1da177e4 LT |
646 | | (setbuf.mode & S_IRWXUGO); |
647 | shp->shm_ctim = get_seconds(); | |
648 | break; | |
649 | } | |
650 | ||
651 | default: | |
652 | err = -EINVAL; | |
653 | goto out; | |
654 | } | |
655 | ||
656 | err = 0; | |
657 | out_unlock_up: | |
658 | shm_unlock(shp); | |
659 | out_up: | |
660 | up(&shm_ids.sem); | |
661 | goto out; | |
662 | out_unlock: | |
663 | shm_unlock(shp); | |
664 | out: | |
665 | return err; | |
666 | } | |
667 | ||
668 | /* | |
669 | * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists. | |
670 | * | |
671 | * NOTE! Despite the name, this is NOT a direct system call entrypoint. The | |
672 | * "raddr" thing points to kernel space, and there has to be a wrapper around | |
673 | * this. | |
674 | */ | |
675 | long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr) | |
676 | { | |
677 | struct shmid_kernel *shp; | |
678 | unsigned long addr; | |
679 | unsigned long size; | |
680 | struct file * file; | |
681 | int err; | |
682 | unsigned long flags; | |
683 | unsigned long prot; | |
684 | unsigned long o_flags; | |
685 | int acc_mode; | |
686 | void *user_addr; | |
687 | ||
688 | if (shmid < 0) { | |
689 | err = -EINVAL; | |
690 | goto out; | |
691 | } else if ((addr = (ulong)shmaddr)) { | |
692 | if (addr & (SHMLBA-1)) { | |
693 | if (shmflg & SHM_RND) | |
694 | addr &= ~(SHMLBA-1); /* round down */ | |
695 | else | |
696 | #ifndef __ARCH_FORCE_SHMLBA | |
697 | if (addr & ~PAGE_MASK) | |
698 | #endif | |
699 | return -EINVAL; | |
700 | } | |
701 | flags = MAP_SHARED | MAP_FIXED; | |
702 | } else { | |
703 | if ((shmflg & SHM_REMAP)) | |
704 | return -EINVAL; | |
705 | ||
706 | flags = MAP_SHARED; | |
707 | } | |
708 | ||
709 | if (shmflg & SHM_RDONLY) { | |
710 | prot = PROT_READ; | |
711 | o_flags = O_RDONLY; | |
712 | acc_mode = S_IRUGO; | |
713 | } else { | |
714 | prot = PROT_READ | PROT_WRITE; | |
715 | o_flags = O_RDWR; | |
716 | acc_mode = S_IRUGO | S_IWUGO; | |
717 | } | |
718 | if (shmflg & SHM_EXEC) { | |
719 | prot |= PROT_EXEC; | |
720 | acc_mode |= S_IXUGO; | |
721 | } | |
722 | ||
723 | /* | |
724 | * We cannot rely on the fs check since SYSV IPC does have an | |
725 | * additional creator id... | |
726 | */ | |
727 | shp = shm_lock(shmid); | |
728 | if(shp == NULL) { | |
729 | err = -EINVAL; | |
730 | goto out; | |
731 | } | |
732 | err = shm_checkid(shp,shmid); | |
733 | if (err) { | |
734 | shm_unlock(shp); | |
735 | goto out; | |
736 | } | |
737 | if (ipcperms(&shp->shm_perm, acc_mode)) { | |
738 | shm_unlock(shp); | |
739 | err = -EACCES; | |
740 | goto out; | |
741 | } | |
742 | ||
743 | err = security_shm_shmat(shp, shmaddr, shmflg); | |
744 | if (err) { | |
745 | shm_unlock(shp); | |
746 | return err; | |
747 | } | |
748 | ||
749 | file = shp->shm_file; | |
750 | size = i_size_read(file->f_dentry->d_inode); | |
751 | shp->shm_nattch++; | |
752 | shm_unlock(shp); | |
753 | ||
754 | down_write(¤t->mm->mmap_sem); | |
755 | if (addr && !(shmflg & SHM_REMAP)) { | |
756 | user_addr = ERR_PTR(-EINVAL); | |
757 | if (find_vma_intersection(current->mm, addr, addr + size)) | |
758 | goto invalid; | |
759 | /* | |
760 | * If shm segment goes below stack, make sure there is some | |
761 | * space left for the stack to grow (at least 4 pages). | |
762 | */ | |
763 | if (addr < current->mm->start_stack && | |
764 | addr > current->mm->start_stack - size - PAGE_SIZE * 5) | |
765 | goto invalid; | |
766 | } | |
767 | ||
768 | user_addr = (void*) do_mmap (file, addr, size, prot, flags, 0); | |
769 | ||
770 | invalid: | |
771 | up_write(¤t->mm->mmap_sem); | |
772 | ||
773 | down (&shm_ids.sem); | |
774 | if(!(shp = shm_lock(shmid))) | |
775 | BUG(); | |
776 | shp->shm_nattch--; | |
777 | if(shp->shm_nattch == 0 && | |
b33291c0 | 778 | shp->shm_perm.mode & SHM_DEST) |
1da177e4 LT |
779 | shm_destroy (shp); |
780 | else | |
781 | shm_unlock(shp); | |
782 | up (&shm_ids.sem); | |
783 | ||
784 | *raddr = (unsigned long) user_addr; | |
785 | err = 0; | |
786 | if (IS_ERR(user_addr)) | |
787 | err = PTR_ERR(user_addr); | |
788 | out: | |
789 | return err; | |
790 | } | |
791 | ||
7d87e14c SR |
792 | asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg) |
793 | { | |
794 | unsigned long ret; | |
795 | long err; | |
796 | ||
797 | err = do_shmat(shmid, shmaddr, shmflg, &ret); | |
798 | if (err) | |
799 | return err; | |
800 | force_successful_syscall_return(); | |
801 | return (long)ret; | |
802 | } | |
803 | ||
1da177e4 LT |
804 | /* |
805 | * detach and kill segment if marked destroyed. | |
806 | * The work is done in shm_close. | |
807 | */ | |
808 | asmlinkage long sys_shmdt(char __user *shmaddr) | |
809 | { | |
810 | struct mm_struct *mm = current->mm; | |
811 | struct vm_area_struct *vma, *next; | |
812 | unsigned long addr = (unsigned long)shmaddr; | |
813 | loff_t size = 0; | |
814 | int retval = -EINVAL; | |
815 | ||
816 | down_write(&mm->mmap_sem); | |
817 | ||
818 | /* | |
819 | * This function tries to be smart and unmap shm segments that | |
820 | * were modified by partial mlock or munmap calls: | |
821 | * - It first determines the size of the shm segment that should be | |
822 | * unmapped: It searches for a vma that is backed by shm and that | |
823 | * started at address shmaddr. It records it's size and then unmaps | |
824 | * it. | |
825 | * - Then it unmaps all shm vmas that started at shmaddr and that | |
826 | * are within the initially determined size. | |
827 | * Errors from do_munmap are ignored: the function only fails if | |
828 | * it's called with invalid parameters or if it's called to unmap | |
829 | * a part of a vma. Both calls in this function are for full vmas, | |
830 | * the parameters are directly copied from the vma itself and always | |
831 | * valid - therefore do_munmap cannot fail. (famous last words?) | |
832 | */ | |
833 | /* | |
834 | * If it had been mremap()'d, the starting address would not | |
835 | * match the usual checks anyway. So assume all vma's are | |
836 | * above the starting address given. | |
837 | */ | |
838 | vma = find_vma(mm, addr); | |
839 | ||
840 | while (vma) { | |
841 | next = vma->vm_next; | |
842 | ||
843 | /* | |
844 | * Check if the starting address would match, i.e. it's | |
845 | * a fragment created by mprotect() and/or munmap(), or it | |
846 | * otherwise it starts at this address with no hassles. | |
847 | */ | |
848 | if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) && | |
849 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) { | |
850 | ||
851 | ||
852 | size = vma->vm_file->f_dentry->d_inode->i_size; | |
853 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); | |
854 | /* | |
855 | * We discovered the size of the shm segment, so | |
856 | * break out of here and fall through to the next | |
857 | * loop that uses the size information to stop | |
858 | * searching for matching vma's. | |
859 | */ | |
860 | retval = 0; | |
861 | vma = next; | |
862 | break; | |
863 | } | |
864 | vma = next; | |
865 | } | |
866 | ||
867 | /* | |
868 | * We need look no further than the maximum address a fragment | |
869 | * could possibly have landed at. Also cast things to loff_t to | |
870 | * prevent overflows and make comparisions vs. equal-width types. | |
871 | */ | |
872 | while (vma && (loff_t)(vma->vm_end - addr) <= size) { | |
873 | next = vma->vm_next; | |
874 | ||
875 | /* finding a matching vma now does not alter retval */ | |
876 | if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) && | |
877 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) | |
878 | ||
879 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); | |
880 | vma = next; | |
881 | } | |
882 | ||
883 | up_write(&mm->mmap_sem); | |
884 | return retval; | |
885 | } | |
886 | ||
887 | #ifdef CONFIG_PROC_FS | |
19b4946c | 888 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it) |
1da177e4 | 889 | { |
19b4946c MW |
890 | struct shmid_kernel *shp = it; |
891 | char *format; | |
1da177e4 | 892 | |
1da177e4 LT |
893 | #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n" |
894 | #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n" | |
1da177e4 | 895 | |
19b4946c MW |
896 | if (sizeof(size_t) <= sizeof(int)) |
897 | format = SMALL_STRING; | |
898 | else | |
899 | format = BIG_STRING; | |
900 | return seq_printf(s, format, | |
901 | shp->shm_perm.key, | |
902 | shp->id, | |
b33291c0 | 903 | shp->shm_perm.mode, |
19b4946c MW |
904 | shp->shm_segsz, |
905 | shp->shm_cprid, | |
906 | shp->shm_lprid, | |
907 | is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch, | |
908 | shp->shm_perm.uid, | |
909 | shp->shm_perm.gid, | |
910 | shp->shm_perm.cuid, | |
911 | shp->shm_perm.cgid, | |
912 | shp->shm_atim, | |
913 | shp->shm_dtim, | |
914 | shp->shm_ctim); | |
1da177e4 LT |
915 | } |
916 | #endif |