blob: b58c651d31ae23a36c58a1de3005e6b5d46a2662 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/shmem_fs.h>
27#include <linux/security.h>
28#include <linux/syscalls.h>
29#include <linux/audit.h>
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -070030#include <linux/ptrace.h>
Mike Waychison19b49462005-09-06 15:17:10 -070031#include <linux/seq_file.h>
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -070032
Linus Torvalds1da177e2005-04-16 15:20:36 -070033#include <asm/uaccess.h>
34
35#include "util.h"
36
37#define shm_flags shm_perm.mode
38
39static struct file_operations shm_file_operations;
40static struct vm_operations_struct shm_vm_ops;
41
42static 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
50static int newseg (key_t key, int shmflg, size_t size);
51static void shm_open (struct vm_area_struct *shmd);
52static void shm_close (struct vm_area_struct *shmd);
53#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -070054static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
Linus Torvalds1da177e2005-04-16 15:20:36 -070055#endif
56
57size_t shm_ctlmax = SHMMAX;
58size_t shm_ctlall = SHMALL;
59int shm_ctlmni = SHMMNI;
60
61static int shm_tot; /* total number of shared memory pages */
62
63void __init shm_init (void)
64{
65 ipc_init_ids(&shm_ids, 1);
Mike Waychison19b49462005-09-06 15:17:10 -070066 ipc_init_proc_interface("sysvipc/shm",
67 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
68 &shm_ids,
69 sysvipc_shm_proc_show);
Linus Torvalds1da177e2005-04-16 15:20:36 -070070}
71
72static inline int shm_checkid(struct shmid_kernel *s, int id)
73{
74 if (ipc_checkid(&shm_ids,&s->shm_perm,id))
75 return -EIDRM;
76 return 0;
77}
78
79static inline struct shmid_kernel *shm_rmid(int id)
80{
81 return (struct shmid_kernel *)ipc_rmid(&shm_ids,id);
82}
83
84static inline int shm_addid(struct shmid_kernel *shp)
85{
86 return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni);
87}
88
89
90
91static inline void shm_inc (int id) {
92 struct shmid_kernel *shp;
93
94 if(!(shp = shm_lock(id)))
95 BUG();
96 shp->shm_atim = get_seconds();
97 shp->shm_lprid = current->tgid;
98 shp->shm_nattch++;
99 shm_unlock(shp);
100}
101
102/* This is called by fork, once for every shm attach. */
103static void shm_open (struct vm_area_struct *shmd)
104{
105 shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino);
106}
107
108/*
109 * shm_destroy - free the struct shmid_kernel
110 *
111 * @shp: struct to free
112 *
113 * It has to be called with shp and shm_ids.sem locked,
114 * but returns with shp unlocked and freed.
115 */
116static void shm_destroy (struct shmid_kernel *shp)
117{
118 shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
119 shm_rmid (shp->id);
120 shm_unlock(shp);
121 if (!is_file_hugepages(shp->shm_file))
122 shmem_lock(shp->shm_file, 0, shp->mlock_user);
123 else
124 user_shm_unlock(shp->shm_file->f_dentry->d_inode->i_size,
125 shp->mlock_user);
126 fput (shp->shm_file);
127 security_shm_free(shp);
128 ipc_rcu_putref(shp);
129}
130
131/*
132 * remove the attach descriptor shmd.
133 * free memory for segment if it is marked destroyed.
134 * The descriptor has already been removed from the current->mm->mmap list
135 * and will later be kfree()d.
136 */
137static void shm_close (struct vm_area_struct *shmd)
138{
139 struct file * file = shmd->vm_file;
140 int id = file->f_dentry->d_inode->i_ino;
141 struct shmid_kernel *shp;
142
143 down (&shm_ids.sem);
144 /* remove from the list of attaches of the shm segment */
145 if(!(shp = shm_lock(id)))
146 BUG();
147 shp->shm_lprid = current->tgid;
148 shp->shm_dtim = get_seconds();
149 shp->shm_nattch--;
150 if(shp->shm_nattch == 0 &&
151 shp->shm_flags & SHM_DEST)
152 shm_destroy (shp);
153 else
154 shm_unlock(shp);
155 up (&shm_ids.sem);
156}
157
158static int shm_mmap(struct file * file, struct vm_area_struct * vma)
159{
160 file_accessed(file);
161 vma->vm_ops = &shm_vm_ops;
162 shm_inc(file->f_dentry->d_inode->i_ino);
163 return 0;
164}
165
166static struct file_operations shm_file_operations = {
167 .mmap = shm_mmap
168};
169
170static struct vm_operations_struct shm_vm_ops = {
171 .open = shm_open, /* callback for a new vm-area open */
172 .close = shm_close, /* callback for when the vm-area is released */
173 .nopage = shmem_nopage,
Andrew Morton6ade43f2005-08-01 21:11:45 -0700174#if defined(CONFIG_NUMA) && defined(CONFIG_SHMEM)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 .set_policy = shmem_set_policy,
176 .get_policy = shmem_get_policy,
177#endif
178};
179
180static int newseg (key_t key, int shmflg, size_t size)
181{
182 int error;
183 struct shmid_kernel *shp;
184 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
185 struct file * file;
186 char name[13];
187 int id;
188
189 if (size < SHMMIN || size > shm_ctlmax)
190 return -EINVAL;
191
192 if (shm_tot + numpages >= shm_ctlall)
193 return -ENOSPC;
194
195 shp = ipc_rcu_alloc(sizeof(*shp));
196 if (!shp)
197 return -ENOMEM;
198
199 shp->shm_perm.key = key;
200 shp->shm_flags = (shmflg & S_IRWXUGO);
201 shp->mlock_user = NULL;
202
203 shp->shm_perm.security = NULL;
204 error = security_shm_alloc(shp);
205 if (error) {
206 ipc_rcu_putref(shp);
207 return error;
208 }
209
210 if (shmflg & SHM_HUGETLB) {
211 /* hugetlb_zero_setup takes care of mlock user accounting */
212 file = hugetlb_zero_setup(size);
213 shp->mlock_user = current->user;
214 } else {
215 sprintf (name, "SYSV%08x", key);
216 file = shmem_file_setup(name, size, VM_ACCOUNT);
217 }
218 error = PTR_ERR(file);
219 if (IS_ERR(file))
220 goto no_file;
221
222 error = -ENOSPC;
223 id = shm_addid(shp);
224 if(id == -1)
225 goto no_id;
226
227 shp->shm_cprid = current->tgid;
228 shp->shm_lprid = 0;
229 shp->shm_atim = shp->shm_dtim = 0;
230 shp->shm_ctim = get_seconds();
231 shp->shm_segsz = size;
232 shp->shm_nattch = 0;
233 shp->id = shm_buildid(id,shp->shm_perm.seq);
234 shp->shm_file = file;
235 file->f_dentry->d_inode->i_ino = shp->id;
Krishnakumar R551110a2005-10-29 18:16:45 -0700236
237 /* Hugetlb ops would have already been assigned. */
238 if (!(shmflg & SHM_HUGETLB))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 file->f_op = &shm_file_operations;
Krishnakumar R551110a2005-10-29 18:16:45 -0700240
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 shm_tot += numpages;
242 shm_unlock(shp);
243 return shp->id;
244
245no_id:
246 fput(file);
247no_file:
248 security_shm_free(shp);
249 ipc_rcu_putref(shp);
250 return error;
251}
252
253asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
254{
255 struct shmid_kernel *shp;
256 int err, id = 0;
257
258 down(&shm_ids.sem);
259 if (key == IPC_PRIVATE) {
260 err = newseg(key, shmflg, size);
261 } else if ((id = ipc_findkey(&shm_ids, key)) == -1) {
262 if (!(shmflg & IPC_CREAT))
263 err = -ENOENT;
264 else
265 err = newseg(key, shmflg, size);
266 } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
267 err = -EEXIST;
268 } else {
269 shp = shm_lock(id);
270 if(shp==NULL)
271 BUG();
272 if (shp->shm_segsz < size)
273 err = -EINVAL;
274 else if (ipcperms(&shp->shm_perm, shmflg))
275 err = -EACCES;
276 else {
277 int shmid = shm_buildid(id, shp->shm_perm.seq);
278 err = security_shm_associate(shp, shmflg);
279 if (!err)
280 err = shmid;
281 }
282 shm_unlock(shp);
283 }
284 up(&shm_ids.sem);
285
286 return err;
287}
288
289static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
290{
291 switch(version) {
292 case IPC_64:
293 return copy_to_user(buf, in, sizeof(*in));
294 case IPC_OLD:
295 {
296 struct shmid_ds out;
297
298 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
299 out.shm_segsz = in->shm_segsz;
300 out.shm_atime = in->shm_atime;
301 out.shm_dtime = in->shm_dtime;
302 out.shm_ctime = in->shm_ctime;
303 out.shm_cpid = in->shm_cpid;
304 out.shm_lpid = in->shm_lpid;
305 out.shm_nattch = in->shm_nattch;
306
307 return copy_to_user(buf, &out, sizeof(out));
308 }
309 default:
310 return -EINVAL;
311 }
312}
313
314struct shm_setbuf {
315 uid_t uid;
316 gid_t gid;
317 mode_t mode;
318};
319
320static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
321{
322 switch(version) {
323 case IPC_64:
324 {
325 struct shmid64_ds tbuf;
326
327 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
328 return -EFAULT;
329
330 out->uid = tbuf.shm_perm.uid;
331 out->gid = tbuf.shm_perm.gid;
332 out->mode = tbuf.shm_flags;
333
334 return 0;
335 }
336 case IPC_OLD:
337 {
338 struct shmid_ds tbuf_old;
339
340 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
341 return -EFAULT;
342
343 out->uid = tbuf_old.shm_perm.uid;
344 out->gid = tbuf_old.shm_perm.gid;
345 out->mode = tbuf_old.shm_flags;
346
347 return 0;
348 }
349 default:
350 return -EINVAL;
351 }
352}
353
354static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
355{
356 switch(version) {
357 case IPC_64:
358 return copy_to_user(buf, in, sizeof(*in));
359 case IPC_OLD:
360 {
361 struct shminfo out;
362
363 if(in->shmmax > INT_MAX)
364 out.shmmax = INT_MAX;
365 else
366 out.shmmax = (int)in->shmmax;
367
368 out.shmmin = in->shmmin;
369 out.shmmni = in->shmmni;
370 out.shmseg = in->shmseg;
371 out.shmall = in->shmall;
372
373 return copy_to_user(buf, &out, sizeof(out));
374 }
375 default:
376 return -EINVAL;
377 }
378}
379
380static void shm_get_stat(unsigned long *rss, unsigned long *swp)
381{
382 int i;
383
384 *rss = 0;
385 *swp = 0;
386
387 for (i = 0; i <= shm_ids.max_id; i++) {
388 struct shmid_kernel *shp;
389 struct inode *inode;
390
391 shp = shm_get(i);
392 if(!shp)
393 continue;
394
395 inode = shp->shm_file->f_dentry->d_inode;
396
397 if (is_file_hugepages(shp->shm_file)) {
398 struct address_space *mapping = inode->i_mapping;
399 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
400 } else {
401 struct shmem_inode_info *info = SHMEM_I(inode);
402 spin_lock(&info->lock);
403 *rss += inode->i_mapping->nrpages;
404 *swp += info->swapped;
405 spin_unlock(&info->lock);
406 }
407 }
408}
409
410asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
411{
412 struct shm_setbuf setbuf;
413 struct shmid_kernel *shp;
414 int err, version;
415
416 if (cmd < 0 || shmid < 0) {
417 err = -EINVAL;
418 goto out;
419 }
420
421 version = ipc_parse_version(&cmd);
422
423 switch (cmd) { /* replace with proc interface ? */
424 case IPC_INFO:
425 {
426 struct shminfo64 shminfo;
427
428 err = security_shm_shmctl(NULL, cmd);
429 if (err)
430 return err;
431
432 memset(&shminfo,0,sizeof(shminfo));
433 shminfo.shmmni = shminfo.shmseg = shm_ctlmni;
434 shminfo.shmmax = shm_ctlmax;
435 shminfo.shmall = shm_ctlall;
436
437 shminfo.shmmin = SHMMIN;
438 if(copy_shminfo_to_user (buf, &shminfo, version))
439 return -EFAULT;
440 /* reading a integer is always atomic */
441 err= shm_ids.max_id;
442 if(err<0)
443 err = 0;
444 goto out;
445 }
446 case SHM_INFO:
447 {
448 struct shm_info shm_info;
449
450 err = security_shm_shmctl(NULL, cmd);
451 if (err)
452 return err;
453
454 memset(&shm_info,0,sizeof(shm_info));
455 down(&shm_ids.sem);
456 shm_info.used_ids = shm_ids.in_use;
457 shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp);
458 shm_info.shm_tot = shm_tot;
459 shm_info.swap_attempts = 0;
460 shm_info.swap_successes = 0;
461 err = shm_ids.max_id;
462 up(&shm_ids.sem);
463 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
464 err = -EFAULT;
465 goto out;
466 }
467
468 err = err < 0 ? 0 : err;
469 goto out;
470 }
471 case SHM_STAT:
472 case IPC_STAT:
473 {
474 struct shmid64_ds tbuf;
475 int result;
476 memset(&tbuf, 0, sizeof(tbuf));
477 shp = shm_lock(shmid);
478 if(shp==NULL) {
479 err = -EINVAL;
480 goto out;
481 } else if(cmd==SHM_STAT) {
482 err = -EINVAL;
483 if (shmid > shm_ids.max_id)
484 goto out_unlock;
485 result = shm_buildid(shmid, shp->shm_perm.seq);
486 } else {
487 err = shm_checkid(shp,shmid);
488 if(err)
489 goto out_unlock;
490 result = 0;
491 }
492 err=-EACCES;
493 if (ipcperms (&shp->shm_perm, S_IRUGO))
494 goto out_unlock;
495 err = security_shm_shmctl(shp, cmd);
496 if (err)
497 goto out_unlock;
498 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
499 tbuf.shm_segsz = shp->shm_segsz;
500 tbuf.shm_atime = shp->shm_atim;
501 tbuf.shm_dtime = shp->shm_dtim;
502 tbuf.shm_ctime = shp->shm_ctim;
503 tbuf.shm_cpid = shp->shm_cprid;
504 tbuf.shm_lpid = shp->shm_lprid;
505 if (!is_file_hugepages(shp->shm_file))
506 tbuf.shm_nattch = shp->shm_nattch;
507 else
508 tbuf.shm_nattch = file_count(shp->shm_file) - 1;
509 shm_unlock(shp);
510 if(copy_shmid_to_user (buf, &tbuf, version))
511 err = -EFAULT;
512 else
513 err = result;
514 goto out;
515 }
516 case SHM_LOCK:
517 case SHM_UNLOCK:
518 {
519 shp = shm_lock(shmid);
520 if(shp==NULL) {
521 err = -EINVAL;
522 goto out;
523 }
524 err = shm_checkid(shp,shmid);
525 if(err)
526 goto out_unlock;
527
528 if (!capable(CAP_IPC_LOCK)) {
529 err = -EPERM;
530 if (current->euid != shp->shm_perm.uid &&
531 current->euid != shp->shm_perm.cuid)
532 goto out_unlock;
533 if (cmd == SHM_LOCK &&
534 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
535 goto out_unlock;
536 }
537
538 err = security_shm_shmctl(shp, cmd);
539 if (err)
540 goto out_unlock;
541
542 if(cmd==SHM_LOCK) {
543 struct user_struct * user = current->user;
544 if (!is_file_hugepages(shp->shm_file)) {
545 err = shmem_lock(shp->shm_file, 1, user);
546 if (!err) {
547 shp->shm_flags |= SHM_LOCKED;
548 shp->mlock_user = user;
549 }
550 }
551 } else if (!is_file_hugepages(shp->shm_file)) {
552 shmem_lock(shp->shm_file, 0, shp->mlock_user);
553 shp->shm_flags &= ~SHM_LOCKED;
554 shp->mlock_user = NULL;
555 }
556 shm_unlock(shp);
557 goto out;
558 }
559 case IPC_RMID:
560 {
561 /*
562 * We cannot simply remove the file. The SVID states
563 * that the block remains until the last person
564 * detaches from it, then is deleted. A shmat() on
565 * an RMID segment is legal in older Linux and if
566 * we change it apps break...
567 *
568 * Instead we set a destroyed flag, and then blow
569 * the name away when the usage hits zero.
570 */
571 down(&shm_ids.sem);
572 shp = shm_lock(shmid);
573 err = -EINVAL;
574 if (shp == NULL)
575 goto out_up;
576 err = shm_checkid(shp, shmid);
577 if(err)
578 goto out_unlock_up;
579
580 if (current->euid != shp->shm_perm.uid &&
581 current->euid != shp->shm_perm.cuid &&
582 !capable(CAP_SYS_ADMIN)) {
583 err=-EPERM;
584 goto out_unlock_up;
585 }
586
587 err = security_shm_shmctl(shp, cmd);
588 if (err)
589 goto out_unlock_up;
590
591 if (shp->shm_nattch){
592 shp->shm_flags |= SHM_DEST;
593 /* Do not find it any more */
594 shp->shm_perm.key = IPC_PRIVATE;
595 shm_unlock(shp);
596 } else
597 shm_destroy (shp);
598 up(&shm_ids.sem);
599 goto out;
600 }
601
602 case IPC_SET:
603 {
604 if (copy_shmid_from_user (&setbuf, buf, version)) {
605 err = -EFAULT;
606 goto out;
607 }
608 if ((err = audit_ipc_perms(0, setbuf.uid, setbuf.gid, setbuf.mode)))
609 return err;
610 down(&shm_ids.sem);
611 shp = shm_lock(shmid);
612 err=-EINVAL;
613 if(shp==NULL)
614 goto out_up;
615 err = shm_checkid(shp,shmid);
616 if(err)
617 goto out_unlock_up;
618 err=-EPERM;
619 if (current->euid != shp->shm_perm.uid &&
620 current->euid != shp->shm_perm.cuid &&
621 !capable(CAP_SYS_ADMIN)) {
622 goto out_unlock_up;
623 }
624
625 err = security_shm_shmctl(shp, cmd);
626 if (err)
627 goto out_unlock_up;
628
629 shp->shm_perm.uid = setbuf.uid;
630 shp->shm_perm.gid = setbuf.gid;
631 shp->shm_flags = (shp->shm_flags & ~S_IRWXUGO)
632 | (setbuf.mode & S_IRWXUGO);
633 shp->shm_ctim = get_seconds();
634 break;
635 }
636
637 default:
638 err = -EINVAL;
639 goto out;
640 }
641
642 err = 0;
643out_unlock_up:
644 shm_unlock(shp);
645out_up:
646 up(&shm_ids.sem);
647 goto out;
648out_unlock:
649 shm_unlock(shp);
650out:
651 return err;
652}
653
654/*
655 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
656 *
657 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
658 * "raddr" thing points to kernel space, and there has to be a wrapper around
659 * this.
660 */
661long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
662{
663 struct shmid_kernel *shp;
664 unsigned long addr;
665 unsigned long size;
666 struct file * file;
667 int err;
668 unsigned long flags;
669 unsigned long prot;
670 unsigned long o_flags;
671 int acc_mode;
672 void *user_addr;
673
674 if (shmid < 0) {
675 err = -EINVAL;
676 goto out;
677 } else if ((addr = (ulong)shmaddr)) {
678 if (addr & (SHMLBA-1)) {
679 if (shmflg & SHM_RND)
680 addr &= ~(SHMLBA-1); /* round down */
681 else
682#ifndef __ARCH_FORCE_SHMLBA
683 if (addr & ~PAGE_MASK)
684#endif
685 return -EINVAL;
686 }
687 flags = MAP_SHARED | MAP_FIXED;
688 } else {
689 if ((shmflg & SHM_REMAP))
690 return -EINVAL;
691
692 flags = MAP_SHARED;
693 }
694
695 if (shmflg & SHM_RDONLY) {
696 prot = PROT_READ;
697 o_flags = O_RDONLY;
698 acc_mode = S_IRUGO;
699 } else {
700 prot = PROT_READ | PROT_WRITE;
701 o_flags = O_RDWR;
702 acc_mode = S_IRUGO | S_IWUGO;
703 }
704 if (shmflg & SHM_EXEC) {
705 prot |= PROT_EXEC;
706 acc_mode |= S_IXUGO;
707 }
708
709 /*
710 * We cannot rely on the fs check since SYSV IPC does have an
711 * additional creator id...
712 */
713 shp = shm_lock(shmid);
714 if(shp == NULL) {
715 err = -EINVAL;
716 goto out;
717 }
718 err = shm_checkid(shp,shmid);
719 if (err) {
720 shm_unlock(shp);
721 goto out;
722 }
723 if (ipcperms(&shp->shm_perm, acc_mode)) {
724 shm_unlock(shp);
725 err = -EACCES;
726 goto out;
727 }
728
729 err = security_shm_shmat(shp, shmaddr, shmflg);
730 if (err) {
731 shm_unlock(shp);
732 return err;
733 }
734
735 file = shp->shm_file;
736 size = i_size_read(file->f_dentry->d_inode);
737 shp->shm_nattch++;
738 shm_unlock(shp);
739
740 down_write(&current->mm->mmap_sem);
741 if (addr && !(shmflg & SHM_REMAP)) {
742 user_addr = ERR_PTR(-EINVAL);
743 if (find_vma_intersection(current->mm, addr, addr + size))
744 goto invalid;
745 /*
746 * If shm segment goes below stack, make sure there is some
747 * space left for the stack to grow (at least 4 pages).
748 */
749 if (addr < current->mm->start_stack &&
750 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
751 goto invalid;
752 }
753
754 user_addr = (void*) do_mmap (file, addr, size, prot, flags, 0);
755
756invalid:
757 up_write(&current->mm->mmap_sem);
758
759 down (&shm_ids.sem);
760 if(!(shp = shm_lock(shmid)))
761 BUG();
762 shp->shm_nattch--;
763 if(shp->shm_nattch == 0 &&
764 shp->shm_flags & SHM_DEST)
765 shm_destroy (shp);
766 else
767 shm_unlock(shp);
768 up (&shm_ids.sem);
769
770 *raddr = (unsigned long) user_addr;
771 err = 0;
772 if (IS_ERR(user_addr))
773 err = PTR_ERR(user_addr);
774out:
775 return err;
776}
777
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -0700778asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
779{
780 unsigned long ret;
781 long err;
782
783 err = do_shmat(shmid, shmaddr, shmflg, &ret);
784 if (err)
785 return err;
786 force_successful_syscall_return();
787 return (long)ret;
788}
789
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790/*
791 * detach and kill segment if marked destroyed.
792 * The work is done in shm_close.
793 */
794asmlinkage long sys_shmdt(char __user *shmaddr)
795{
796 struct mm_struct *mm = current->mm;
797 struct vm_area_struct *vma, *next;
798 unsigned long addr = (unsigned long)shmaddr;
799 loff_t size = 0;
800 int retval = -EINVAL;
801
802 down_write(&mm->mmap_sem);
803
804 /*
805 * This function tries to be smart and unmap shm segments that
806 * were modified by partial mlock or munmap calls:
807 * - It first determines the size of the shm segment that should be
808 * unmapped: It searches for a vma that is backed by shm and that
809 * started at address shmaddr. It records it's size and then unmaps
810 * it.
811 * - Then it unmaps all shm vmas that started at shmaddr and that
812 * are within the initially determined size.
813 * Errors from do_munmap are ignored: the function only fails if
814 * it's called with invalid parameters or if it's called to unmap
815 * a part of a vma. Both calls in this function are for full vmas,
816 * the parameters are directly copied from the vma itself and always
817 * valid - therefore do_munmap cannot fail. (famous last words?)
818 */
819 /*
820 * If it had been mremap()'d, the starting address would not
821 * match the usual checks anyway. So assume all vma's are
822 * above the starting address given.
823 */
824 vma = find_vma(mm, addr);
825
826 while (vma) {
827 next = vma->vm_next;
828
829 /*
830 * Check if the starting address would match, i.e. it's
831 * a fragment created by mprotect() and/or munmap(), or it
832 * otherwise it starts at this address with no hassles.
833 */
834 if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
835 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
836
837
838 size = vma->vm_file->f_dentry->d_inode->i_size;
839 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
840 /*
841 * We discovered the size of the shm segment, so
842 * break out of here and fall through to the next
843 * loop that uses the size information to stop
844 * searching for matching vma's.
845 */
846 retval = 0;
847 vma = next;
848 break;
849 }
850 vma = next;
851 }
852
853 /*
854 * We need look no further than the maximum address a fragment
855 * could possibly have landed at. Also cast things to loff_t to
856 * prevent overflows and make comparisions vs. equal-width types.
857 */
858 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
859 next = vma->vm_next;
860
861 /* finding a matching vma now does not alter retval */
862 if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
863 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
864
865 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
866 vma = next;
867 }
868
869 up_write(&mm->mmap_sem);
870 return retval;
871}
872
873#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -0700874static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875{
Mike Waychison19b49462005-09-06 15:17:10 -0700876 struct shmid_kernel *shp = it;
877 char *format;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
880#define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881
Mike Waychison19b49462005-09-06 15:17:10 -0700882 if (sizeof(size_t) <= sizeof(int))
883 format = SMALL_STRING;
884 else
885 format = BIG_STRING;
886 return seq_printf(s, format,
887 shp->shm_perm.key,
888 shp->id,
889 shp->shm_flags,
890 shp->shm_segsz,
891 shp->shm_cprid,
892 shp->shm_lprid,
893 is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch,
894 shp->shm_perm.uid,
895 shp->shm_perm.gid,
896 shp->shm_perm.cuid,
897 shp->shm_perm.cgid,
898 shp->shm_atim,
899 shp->shm_dtim,
900 shp->shm_ctim);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901}
902#endif