Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/ipc/shm.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 21819 byte(s)
Tag kernel26-2.6.12-alx-r9
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> |
31 | #include <linux/ptrace.h> |
32 | |
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 | |
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 | |
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 |