ia64/linux-2.6.18-xen.hg

view ipc/shm.c @ 647:a5bb490065f6

Fix the build after public header sync.
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Wed Aug 13 14:01:49 2008 +0100 (2008-08-13)
parents 831230e53067
children
line source
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 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
18 */
20 #include <linux/slab.h>
21 #include <linux/mm.h>
22 #include <linux/hugetlb.h>
23 #include <linux/shm.h>
24 #include <linux/init.h>
25 #include <linux/file.h>
26 #include <linux/mman.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/capability.h>
32 #include <linux/ptrace.h>
33 #include <linux/seq_file.h>
34 #include <linux/mutex.h>
36 #include <asm/uaccess.h>
38 #include "util.h"
40 static struct file_operations shm_file_operations;
41 static struct vm_operations_struct shm_vm_ops;
43 static struct ipc_ids shm_ids;
45 #define shm_lock(id) ((struct shmid_kernel*)ipc_lock(&shm_ids,id))
46 #define shm_unlock(shp) ipc_unlock(&(shp)->shm_perm)
47 #define shm_get(id) ((struct shmid_kernel*)ipc_get(&shm_ids,id))
48 #define shm_buildid(id, seq) \
49 ipc_buildid(&shm_ids, id, seq)
51 static int newseg (key_t key, int shmflg, size_t size);
52 static void shm_open (struct vm_area_struct *shmd);
53 static void shm_close (struct vm_area_struct *shmd);
54 #ifdef CONFIG_PROC_FS
55 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
56 #endif
58 size_t shm_ctlmax = SHMMAX;
59 size_t shm_ctlall = SHMALL;
60 int shm_ctlmni = SHMMNI;
62 static int shm_tot; /* total number of shared memory pages */
64 void __init shm_init (void)
65 {
66 ipc_init_ids(&shm_ids, 1);
67 ipc_init_proc_interface("sysvipc/shm",
68 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
69 &shm_ids,
70 sysvipc_shm_proc_show);
71 }
73 static inline int shm_checkid(struct shmid_kernel *s, int id)
74 {
75 if (ipc_checkid(&shm_ids,&s->shm_perm,id))
76 return -EIDRM;
77 return 0;
78 }
80 static inline struct shmid_kernel *shm_rmid(int id)
81 {
82 return (struct shmid_kernel *)ipc_rmid(&shm_ids,id);
83 }
85 static inline int shm_addid(struct shmid_kernel *shp)
86 {
87 return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni);
88 }
92 static inline void shm_inc (int id) {
93 struct shmid_kernel *shp;
95 shp = shm_lock(id);
96 BUG_ON(!shp);
97 shp->shm_atim = get_seconds();
98 shp->shm_lprid = current->tgid;
99 shp->shm_nattch++;
100 shm_unlock(shp);
101 }
103 /* This is called by fork, once for every shm attach. */
104 static void shm_open (struct vm_area_struct *shmd)
105 {
106 shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino);
107 }
109 /*
110 * shm_destroy - free the struct shmid_kernel
111 *
112 * @shp: struct to free
113 *
114 * It has to be called with shp and shm_ids.mutex locked,
115 * but returns with shp unlocked and freed.
116 */
117 static void shm_destroy (struct shmid_kernel *shp)
118 {
119 shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
120 shm_rmid (shp->id);
121 shm_unlock(shp);
122 if (!is_file_hugepages(shp->shm_file))
123 shmem_lock(shp->shm_file, 0, shp->mlock_user);
124 else
125 user_shm_unlock(shp->shm_file->f_dentry->d_inode->i_size,
126 shp->mlock_user);
127 fput (shp->shm_file);
128 security_shm_free(shp);
129 ipc_rcu_putref(shp);
130 }
132 /*
133 * remove the attach descriptor shmd.
134 * free memory for segment if it is marked destroyed.
135 * The descriptor has already been removed from the current->mm->mmap list
136 * and will later be kfree()d.
137 */
138 static void shm_close (struct vm_area_struct *shmd)
139 {
140 struct file * file = shmd->vm_file;
141 int id = file->f_dentry->d_inode->i_ino;
142 struct shmid_kernel *shp;
144 mutex_lock(&shm_ids.mutex);
145 /* remove from the list of attaches of the shm segment */
146 shp = shm_lock(id);
147 BUG_ON(!shp);
148 shp->shm_lprid = current->tgid;
149 shp->shm_dtim = get_seconds();
150 shp->shm_nattch--;
151 if(shp->shm_nattch == 0 &&
152 shp->shm_perm.mode & SHM_DEST)
153 shm_destroy (shp);
154 else
155 shm_unlock(shp);
156 mutex_unlock(&shm_ids.mutex);
157 }
159 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
160 {
161 int ret;
163 ret = shmem_mmap(file, vma);
164 if (ret == 0) {
165 vma->vm_ops = &shm_vm_ops;
166 if (!(vma->vm_flags & VM_WRITE))
167 vma->vm_flags &= ~VM_MAYWRITE;
168 shm_inc(file->f_dentry->d_inode->i_ino);
169 }
171 return ret;
172 }
174 static struct file_operations shm_file_operations = {
175 .mmap = shm_mmap,
176 #ifndef CONFIG_MMU
177 .get_unmapped_area = shmem_get_unmapped_area,
178 #endif
179 };
181 static struct vm_operations_struct shm_vm_ops = {
182 .open = shm_open, /* callback for a new vm-area open */
183 .close = shm_close, /* callback for when the vm-area is released */
184 .nopage = shmem_nopage,
185 #if defined(CONFIG_NUMA) && defined(CONFIG_SHMEM)
186 .set_policy = shmem_set_policy,
187 .get_policy = shmem_get_policy,
188 #endif
189 };
191 static int newseg (key_t key, int shmflg, size_t size)
192 {
193 int error;
194 struct shmid_kernel *shp;
195 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
196 struct file * file;
197 char name[13];
198 int id;
200 if (size < SHMMIN || size > shm_ctlmax)
201 return -EINVAL;
203 if (shm_tot + numpages >= shm_ctlall)
204 return -ENOSPC;
206 shp = ipc_rcu_alloc(sizeof(*shp));
207 if (!shp)
208 return -ENOMEM;
210 shp->shm_perm.key = key;
211 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
212 shp->mlock_user = NULL;
214 shp->shm_perm.security = NULL;
215 error = security_shm_alloc(shp);
216 if (error) {
217 ipc_rcu_putref(shp);
218 return error;
219 }
221 if (shmflg & SHM_HUGETLB) {
222 /* hugetlb_zero_setup takes care of mlock user accounting */
223 file = hugetlb_zero_setup(size);
224 shp->mlock_user = current->user;
225 } else {
226 int acctflag = VM_ACCOUNT;
227 /*
228 * Do not allow no accounting for OVERCOMMIT_NEVER, even
229 * if it's asked for.
230 */
231 if ((shmflg & SHM_NORESERVE) &&
232 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
233 acctflag = 0;
234 sprintf (name, "SYSV%08x", key);
235 file = shmem_file_setup(name, size, acctflag);
236 }
237 error = PTR_ERR(file);
238 if (IS_ERR(file))
239 goto no_file;
241 error = -ENOSPC;
242 id = shm_addid(shp);
243 if(id == -1)
244 goto no_id;
246 shp->shm_cprid = current->tgid;
247 shp->shm_lprid = 0;
248 shp->shm_atim = shp->shm_dtim = 0;
249 shp->shm_ctim = get_seconds();
250 shp->shm_segsz = size;
251 shp->shm_nattch = 0;
252 shp->id = shm_buildid(id,shp->shm_perm.seq);
253 shp->shm_file = file;
254 file->f_dentry->d_inode->i_ino = shp->id;
256 /* Hugetlb ops would have already been assigned. */
257 if (!(shmflg & SHM_HUGETLB))
258 file->f_op = &shm_file_operations;
260 shm_tot += numpages;
261 shm_unlock(shp);
262 return shp->id;
264 no_id:
265 fput(file);
266 no_file:
267 security_shm_free(shp);
268 ipc_rcu_putref(shp);
269 return error;
270 }
272 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
273 {
274 struct shmid_kernel *shp;
275 int err, id = 0;
277 mutex_lock(&shm_ids.mutex);
278 if (key == IPC_PRIVATE) {
279 err = newseg(key, shmflg, size);
280 } else if ((id = ipc_findkey(&shm_ids, key)) == -1) {
281 if (!(shmflg & IPC_CREAT))
282 err = -ENOENT;
283 else
284 err = newseg(key, shmflg, size);
285 } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
286 err = -EEXIST;
287 } else {
288 shp = shm_lock(id);
289 BUG_ON(shp==NULL);
290 if (shp->shm_segsz < size)
291 err = -EINVAL;
292 else if (ipcperms(&shp->shm_perm, shmflg))
293 err = -EACCES;
294 else {
295 int shmid = shm_buildid(id, shp->shm_perm.seq);
296 err = security_shm_associate(shp, shmflg);
297 if (!err)
298 err = shmid;
299 }
300 shm_unlock(shp);
301 }
302 mutex_unlock(&shm_ids.mutex);
304 return err;
305 }
307 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
308 {
309 switch(version) {
310 case IPC_64:
311 return copy_to_user(buf, in, sizeof(*in));
312 case IPC_OLD:
313 {
314 struct shmid_ds out;
316 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
317 out.shm_segsz = in->shm_segsz;
318 out.shm_atime = in->shm_atime;
319 out.shm_dtime = in->shm_dtime;
320 out.shm_ctime = in->shm_ctime;
321 out.shm_cpid = in->shm_cpid;
322 out.shm_lpid = in->shm_lpid;
323 out.shm_nattch = in->shm_nattch;
325 return copy_to_user(buf, &out, sizeof(out));
326 }
327 default:
328 return -EINVAL;
329 }
330 }
332 struct shm_setbuf {
333 uid_t uid;
334 gid_t gid;
335 mode_t mode;
336 };
338 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
339 {
340 switch(version) {
341 case IPC_64:
342 {
343 struct shmid64_ds tbuf;
345 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
346 return -EFAULT;
348 out->uid = tbuf.shm_perm.uid;
349 out->gid = tbuf.shm_perm.gid;
350 out->mode = tbuf.shm_perm.mode;
352 return 0;
353 }
354 case IPC_OLD:
355 {
356 struct shmid_ds tbuf_old;
358 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
359 return -EFAULT;
361 out->uid = tbuf_old.shm_perm.uid;
362 out->gid = tbuf_old.shm_perm.gid;
363 out->mode = tbuf_old.shm_perm.mode;
365 return 0;
366 }
367 default:
368 return -EINVAL;
369 }
370 }
372 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
373 {
374 switch(version) {
375 case IPC_64:
376 return copy_to_user(buf, in, sizeof(*in));
377 case IPC_OLD:
378 {
379 struct shminfo out;
381 if(in->shmmax > INT_MAX)
382 out.shmmax = INT_MAX;
383 else
384 out.shmmax = (int)in->shmmax;
386 out.shmmin = in->shmmin;
387 out.shmmni = in->shmmni;
388 out.shmseg = in->shmseg;
389 out.shmall = in->shmall;
391 return copy_to_user(buf, &out, sizeof(out));
392 }
393 default:
394 return -EINVAL;
395 }
396 }
398 static void shm_get_stat(unsigned long *rss, unsigned long *swp)
399 {
400 int i;
402 *rss = 0;
403 *swp = 0;
405 for (i = 0; i <= shm_ids.max_id; i++) {
406 struct shmid_kernel *shp;
407 struct inode *inode;
409 shp = shm_get(i);
410 if(!shp)
411 continue;
413 inode = shp->shm_file->f_dentry->d_inode;
415 if (is_file_hugepages(shp->shm_file)) {
416 struct address_space *mapping = inode->i_mapping;
417 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
418 } else {
419 struct shmem_inode_info *info = SHMEM_I(inode);
420 spin_lock(&info->lock);
421 *rss += inode->i_mapping->nrpages;
422 *swp += info->swapped;
423 spin_unlock(&info->lock);
424 }
425 }
426 }
428 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
429 {
430 struct shm_setbuf setbuf;
431 struct shmid_kernel *shp;
432 int err, version;
434 if (cmd < 0 || shmid < 0) {
435 err = -EINVAL;
436 goto out;
437 }
439 version = ipc_parse_version(&cmd);
441 switch (cmd) { /* replace with proc interface ? */
442 case IPC_INFO:
443 {
444 struct shminfo64 shminfo;
446 err = security_shm_shmctl(NULL, cmd);
447 if (err)
448 return err;
450 memset(&shminfo,0,sizeof(shminfo));
451 shminfo.shmmni = shminfo.shmseg = shm_ctlmni;
452 shminfo.shmmax = shm_ctlmax;
453 shminfo.shmall = shm_ctlall;
455 shminfo.shmmin = SHMMIN;
456 if(copy_shminfo_to_user (buf, &shminfo, version))
457 return -EFAULT;
458 /* reading a integer is always atomic */
459 err= shm_ids.max_id;
460 if(err<0)
461 err = 0;
462 goto out;
463 }
464 case SHM_INFO:
465 {
466 struct shm_info shm_info;
468 err = security_shm_shmctl(NULL, cmd);
469 if (err)
470 return err;
472 memset(&shm_info,0,sizeof(shm_info));
473 mutex_lock(&shm_ids.mutex);
474 shm_info.used_ids = shm_ids.in_use;
475 shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp);
476 shm_info.shm_tot = shm_tot;
477 shm_info.swap_attempts = 0;
478 shm_info.swap_successes = 0;
479 err = shm_ids.max_id;
480 mutex_unlock(&shm_ids.mutex);
481 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
482 err = -EFAULT;
483 goto out;
484 }
486 err = err < 0 ? 0 : err;
487 goto out;
488 }
489 case SHM_STAT:
490 case IPC_STAT:
491 {
492 struct shmid64_ds tbuf;
493 int result;
494 memset(&tbuf, 0, sizeof(tbuf));
495 shp = shm_lock(shmid);
496 if(shp==NULL) {
497 err = -EINVAL;
498 goto out;
499 } else if(cmd==SHM_STAT) {
500 err = -EINVAL;
501 if (shmid > shm_ids.max_id)
502 goto out_unlock;
503 result = shm_buildid(shmid, shp->shm_perm.seq);
504 } else {
505 err = shm_checkid(shp,shmid);
506 if(err)
507 goto out_unlock;
508 result = 0;
509 }
510 err=-EACCES;
511 if (ipcperms (&shp->shm_perm, S_IRUGO))
512 goto out_unlock;
513 err = security_shm_shmctl(shp, cmd);
514 if (err)
515 goto out_unlock;
516 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
517 tbuf.shm_segsz = shp->shm_segsz;
518 tbuf.shm_atime = shp->shm_atim;
519 tbuf.shm_dtime = shp->shm_dtim;
520 tbuf.shm_ctime = shp->shm_ctim;
521 tbuf.shm_cpid = shp->shm_cprid;
522 tbuf.shm_lpid = shp->shm_lprid;
523 if (!is_file_hugepages(shp->shm_file))
524 tbuf.shm_nattch = shp->shm_nattch;
525 else
526 tbuf.shm_nattch = file_count(shp->shm_file) - 1;
527 shm_unlock(shp);
528 if(copy_shmid_to_user (buf, &tbuf, version))
529 err = -EFAULT;
530 else
531 err = result;
532 goto out;
533 }
534 case SHM_LOCK:
535 case SHM_UNLOCK:
536 {
537 shp = shm_lock(shmid);
538 if(shp==NULL) {
539 err = -EINVAL;
540 goto out;
541 }
542 err = shm_checkid(shp,shmid);
543 if(err)
544 goto out_unlock;
546 err = audit_ipc_obj(&(shp->shm_perm));
547 if (err)
548 goto out_unlock;
550 if (!capable(CAP_IPC_LOCK)) {
551 err = -EPERM;
552 if (current->euid != shp->shm_perm.uid &&
553 current->euid != shp->shm_perm.cuid)
554 goto out_unlock;
555 if (cmd == SHM_LOCK &&
556 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
557 goto out_unlock;
558 }
560 err = security_shm_shmctl(shp, cmd);
561 if (err)
562 goto out_unlock;
564 if(cmd==SHM_LOCK) {
565 struct user_struct * user = current->user;
566 if (!is_file_hugepages(shp->shm_file)) {
567 err = shmem_lock(shp->shm_file, 1, user);
568 if (!err) {
569 shp->shm_perm.mode |= SHM_LOCKED;
570 shp->mlock_user = user;
571 }
572 }
573 } else if (!is_file_hugepages(shp->shm_file)) {
574 shmem_lock(shp->shm_file, 0, shp->mlock_user);
575 shp->shm_perm.mode &= ~SHM_LOCKED;
576 shp->mlock_user = NULL;
577 }
578 shm_unlock(shp);
579 goto out;
580 }
581 case IPC_RMID:
582 {
583 /*
584 * We cannot simply remove the file. The SVID states
585 * that the block remains until the last person
586 * detaches from it, then is deleted. A shmat() on
587 * an RMID segment is legal in older Linux and if
588 * we change it apps break...
589 *
590 * Instead we set a destroyed flag, and then blow
591 * the name away when the usage hits zero.
592 */
593 mutex_lock(&shm_ids.mutex);
594 shp = shm_lock(shmid);
595 err = -EINVAL;
596 if (shp == NULL)
597 goto out_up;
598 err = shm_checkid(shp, shmid);
599 if(err)
600 goto out_unlock_up;
602 err = audit_ipc_obj(&(shp->shm_perm));
603 if (err)
604 goto out_unlock_up;
606 if (current->euid != shp->shm_perm.uid &&
607 current->euid != shp->shm_perm.cuid &&
608 !capable(CAP_SYS_ADMIN)) {
609 err=-EPERM;
610 goto out_unlock_up;
611 }
613 err = security_shm_shmctl(shp, cmd);
614 if (err)
615 goto out_unlock_up;
617 if (shp->shm_nattch){
618 shp->shm_perm.mode |= SHM_DEST;
619 /* Do not find it any more */
620 shp->shm_perm.key = IPC_PRIVATE;
621 shm_unlock(shp);
622 } else
623 shm_destroy (shp);
624 mutex_unlock(&shm_ids.mutex);
625 goto out;
626 }
628 case IPC_SET:
629 {
630 if (copy_shmid_from_user (&setbuf, buf, version)) {
631 err = -EFAULT;
632 goto out;
633 }
634 mutex_lock(&shm_ids.mutex);
635 shp = shm_lock(shmid);
636 err=-EINVAL;
637 if(shp==NULL)
638 goto out_up;
639 err = shm_checkid(shp,shmid);
640 if(err)
641 goto out_unlock_up;
642 err = audit_ipc_obj(&(shp->shm_perm));
643 if (err)
644 goto out_unlock_up;
645 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
646 if (err)
647 goto out_unlock_up;
648 err=-EPERM;
649 if (current->euid != shp->shm_perm.uid &&
650 current->euid != shp->shm_perm.cuid &&
651 !capable(CAP_SYS_ADMIN)) {
652 goto out_unlock_up;
653 }
655 err = security_shm_shmctl(shp, cmd);
656 if (err)
657 goto out_unlock_up;
659 shp->shm_perm.uid = setbuf.uid;
660 shp->shm_perm.gid = setbuf.gid;
661 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
662 | (setbuf.mode & S_IRWXUGO);
663 shp->shm_ctim = get_seconds();
664 break;
665 }
667 default:
668 err = -EINVAL;
669 goto out;
670 }
672 err = 0;
673 out_unlock_up:
674 shm_unlock(shp);
675 out_up:
676 mutex_unlock(&shm_ids.mutex);
677 goto out;
678 out_unlock:
679 shm_unlock(shp);
680 out:
681 return err;
682 }
684 /*
685 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
686 *
687 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
688 * "raddr" thing points to kernel space, and there has to be a wrapper around
689 * this.
690 */
691 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
692 {
693 struct shmid_kernel *shp;
694 unsigned long addr;
695 unsigned long size;
696 struct file * file;
697 int err;
698 unsigned long flags;
699 unsigned long prot;
700 int acc_mode;
701 void *user_addr;
703 if (shmid < 0) {
704 err = -EINVAL;
705 goto out;
706 } else if ((addr = (ulong)shmaddr)) {
707 if (addr & (SHMLBA-1)) {
708 if (shmflg & SHM_RND)
709 addr &= ~(SHMLBA-1); /* round down */
710 else
711 #ifndef __ARCH_FORCE_SHMLBA
712 if (addr & ~PAGE_MASK)
713 #endif
714 return -EINVAL;
715 }
716 flags = MAP_SHARED | MAP_FIXED;
717 } else {
718 if ((shmflg & SHM_REMAP))
719 return -EINVAL;
721 flags = MAP_SHARED;
722 }
724 if (shmflg & SHM_RDONLY) {
725 prot = PROT_READ;
726 acc_mode = S_IRUGO;
727 } else {
728 prot = PROT_READ | PROT_WRITE;
729 acc_mode = S_IRUGO | S_IWUGO;
730 }
731 if (shmflg & SHM_EXEC) {
732 prot |= PROT_EXEC;
733 acc_mode |= S_IXUGO;
734 }
736 /*
737 * We cannot rely on the fs check since SYSV IPC does have an
738 * additional creator id...
739 */
740 shp = shm_lock(shmid);
741 if(shp == NULL) {
742 err = -EINVAL;
743 goto out;
744 }
745 err = shm_checkid(shp,shmid);
746 if (err) {
747 shm_unlock(shp);
748 goto out;
749 }
750 if (ipcperms(&shp->shm_perm, acc_mode)) {
751 shm_unlock(shp);
752 err = -EACCES;
753 goto out;
754 }
756 err = security_shm_shmat(shp, shmaddr, shmflg);
757 if (err) {
758 shm_unlock(shp);
759 return err;
760 }
762 file = shp->shm_file;
763 size = i_size_read(file->f_dentry->d_inode);
764 shp->shm_nattch++;
765 shm_unlock(shp);
767 down_write(&current->mm->mmap_sem);
768 if (addr && !(shmflg & SHM_REMAP)) {
769 user_addr = ERR_PTR(-EINVAL);
770 if (find_vma_intersection(current->mm, addr, addr + size))
771 goto invalid;
772 /*
773 * If shm segment goes below stack, make sure there is some
774 * space left for the stack to grow (at least 4 pages).
775 */
776 if (addr < current->mm->start_stack &&
777 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
778 goto invalid;
779 }
781 user_addr = (void*) do_mmap (file, addr, size, prot, flags, 0);
783 invalid:
784 up_write(&current->mm->mmap_sem);
786 mutex_lock(&shm_ids.mutex);
787 shp = shm_lock(shmid);
788 BUG_ON(!shp);
789 shp->shm_nattch--;
790 if(shp->shm_nattch == 0 &&
791 shp->shm_perm.mode & SHM_DEST)
792 shm_destroy (shp);
793 else
794 shm_unlock(shp);
795 mutex_unlock(&shm_ids.mutex);
797 *raddr = (unsigned long) user_addr;
798 err = 0;
799 if (IS_ERR(user_addr))
800 err = PTR_ERR(user_addr);
801 out:
802 return err;
803 }
805 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
806 {
807 unsigned long ret;
808 long err;
810 err = do_shmat(shmid, shmaddr, shmflg, &ret);
811 if (err)
812 return err;
813 force_successful_syscall_return();
814 return (long)ret;
815 }
817 /*
818 * detach and kill segment if marked destroyed.
819 * The work is done in shm_close.
820 */
821 asmlinkage long sys_shmdt(char __user *shmaddr)
822 {
823 struct mm_struct *mm = current->mm;
824 struct vm_area_struct *vma, *next;
825 unsigned long addr = (unsigned long)shmaddr;
826 loff_t size = 0;
827 int retval = -EINVAL;
829 if (addr & ~PAGE_MASK)
830 return retval;
832 down_write(&mm->mmap_sem);
834 /*
835 * This function tries to be smart and unmap shm segments that
836 * were modified by partial mlock or munmap calls:
837 * - It first determines the size of the shm segment that should be
838 * unmapped: It searches for a vma that is backed by shm and that
839 * started at address shmaddr. It records it's size and then unmaps
840 * it.
841 * - Then it unmaps all shm vmas that started at shmaddr and that
842 * are within the initially determined size.
843 * Errors from do_munmap are ignored: the function only fails if
844 * it's called with invalid parameters or if it's called to unmap
845 * a part of a vma. Both calls in this function are for full vmas,
846 * the parameters are directly copied from the vma itself and always
847 * valid - therefore do_munmap cannot fail. (famous last words?)
848 */
849 /*
850 * If it had been mremap()'d, the starting address would not
851 * match the usual checks anyway. So assume all vma's are
852 * above the starting address given.
853 */
854 vma = find_vma(mm, addr);
856 while (vma) {
857 next = vma->vm_next;
859 /*
860 * Check if the starting address would match, i.e. it's
861 * a fragment created by mprotect() and/or munmap(), or it
862 * otherwise it starts at this address with no hassles.
863 */
864 if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
865 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
868 size = vma->vm_file->f_dentry->d_inode->i_size;
869 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
870 /*
871 * We discovered the size of the shm segment, so
872 * break out of here and fall through to the next
873 * loop that uses the size information to stop
874 * searching for matching vma's.
875 */
876 retval = 0;
877 vma = next;
878 break;
879 }
880 vma = next;
881 }
883 /*
884 * We need look no further than the maximum address a fragment
885 * could possibly have landed at. Also cast things to loff_t to
886 * prevent overflows and make comparisions vs. equal-width types.
887 */
888 size = PAGE_ALIGN(size);
889 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
890 next = vma->vm_next;
892 /* finding a matching vma now does not alter retval */
893 if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
894 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
896 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
897 vma = next;
898 }
900 up_write(&mm->mmap_sem);
901 return retval;
902 }
904 #ifdef CONFIG_PROC_FS
905 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
906 {
907 struct shmid_kernel *shp = it;
908 char *format;
910 #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
911 #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
913 if (sizeof(size_t) <= sizeof(int))
914 format = SMALL_STRING;
915 else
916 format = BIG_STRING;
917 return seq_printf(s, format,
918 shp->shm_perm.key,
919 shp->id,
920 shp->shm_perm.mode,
921 shp->shm_segsz,
922 shp->shm_cprid,
923 shp->shm_lprid,
924 is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch,
925 shp->shm_perm.uid,
926 shp->shm_perm.gid,
927 shp->shm_perm.cuid,
928 shp->shm_perm.cgid,
929 shp->shm_atim,
930 shp->shm_dtim,
931 shp->shm_ctim);
932 }
933 #endif