blob: fe7ae73b698159cadb35290a13f187a6596c7c32 [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 *
Steve Grubb073115d2006-04-02 17:07:33 -040016 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018 */
19
20#include <linux/config.h>
21#include <linux/slab.h>
22#include <linux/mm.h>
23#include <linux/hugetlb.h>
24#include <linux/shm.h>
25#include <linux/init.h>
26#include <linux/file.h>
27#include <linux/mman.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/shmem_fs.h>
29#include <linux/security.h>
30#include <linux/syscalls.h>
31#include <linux/audit.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080032#include <linux/capability.h>
Stephen Rothwell7d87e142005-05-01 08:59:12 -070033#include <linux/ptrace.h>
Mike Waychison19b49462005-09-06 15:17:10 -070034#include <linux/seq_file.h>
Ingo Molnar5f921ae2006-03-26 01:37:17 -080035#include <linux/mutex.h>
Stephen Rothwell7d87e142005-05-01 08:59:12 -070036
Linus Torvalds1da177e2005-04-16 15:20:36 -070037#include <asm/uaccess.h>
38
39#include "util.h"
40
Linus Torvalds1da177e2005-04-16 15:20:36 -070041static struct file_operations shm_file_operations;
42static struct vm_operations_struct shm_vm_ops;
43
44static struct ipc_ids shm_ids;
45
46#define shm_lock(id) ((struct shmid_kernel*)ipc_lock(&shm_ids,id))
47#define shm_unlock(shp) ipc_unlock(&(shp)->shm_perm)
48#define shm_get(id) ((struct shmid_kernel*)ipc_get(&shm_ids,id))
49#define shm_buildid(id, seq) \
50 ipc_buildid(&shm_ids, id, seq)
51
52static int newseg (key_t key, int shmflg, size_t size);
53static void shm_open (struct vm_area_struct *shmd);
54static void shm_close (struct vm_area_struct *shmd);
55#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -070056static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
Linus Torvalds1da177e2005-04-16 15:20:36 -070057#endif
58
59size_t shm_ctlmax = SHMMAX;
60size_t shm_ctlall = SHMALL;
61int shm_ctlmni = SHMMNI;
62
63static int shm_tot; /* total number of shared memory pages */
64
65void __init shm_init (void)
66{
67 ipc_init_ids(&shm_ids, 1);
Mike Waychison19b49462005-09-06 15:17:10 -070068 ipc_init_proc_interface("sysvipc/shm",
69 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
70 &shm_ids,
71 sysvipc_shm_proc_show);
Linus Torvalds1da177e2005-04-16 15:20:36 -070072}
73
74static inline int shm_checkid(struct shmid_kernel *s, int id)
75{
76 if (ipc_checkid(&shm_ids,&s->shm_perm,id))
77 return -EIDRM;
78 return 0;
79}
80
81static inline struct shmid_kernel *shm_rmid(int id)
82{
83 return (struct shmid_kernel *)ipc_rmid(&shm_ids,id);
84}
85
86static inline int shm_addid(struct shmid_kernel *shp)
87{
88 return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni);
89}
90
91
92
93static inline void shm_inc (int id) {
94 struct shmid_kernel *shp;
95
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +020096 shp = shm_lock(id);
97 BUG_ON(!shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 shp->shm_atim = get_seconds();
99 shp->shm_lprid = current->tgid;
100 shp->shm_nattch++;
101 shm_unlock(shp);
102}
103
104/* This is called by fork, once for every shm attach. */
105static void shm_open (struct vm_area_struct *shmd)
106{
107 shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino);
108}
109
110/*
111 * shm_destroy - free the struct shmid_kernel
112 *
113 * @shp: struct to free
114 *
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800115 * It has to be called with shp and shm_ids.mutex locked,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 * but returns with shp unlocked and freed.
117 */
118static void shm_destroy (struct shmid_kernel *shp)
119{
120 shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
121 shm_rmid (shp->id);
122 shm_unlock(shp);
123 if (!is_file_hugepages(shp->shm_file))
124 shmem_lock(shp->shm_file, 0, shp->mlock_user);
125 else
126 user_shm_unlock(shp->shm_file->f_dentry->d_inode->i_size,
127 shp->mlock_user);
128 fput (shp->shm_file);
129 security_shm_free(shp);
130 ipc_rcu_putref(shp);
131}
132
133/*
134 * remove the attach descriptor shmd.
135 * free memory for segment if it is marked destroyed.
136 * The descriptor has already been removed from the current->mm->mmap list
137 * and will later be kfree()d.
138 */
139static void shm_close (struct vm_area_struct *shmd)
140{
141 struct file * file = shmd->vm_file;
142 int id = file->f_dentry->d_inode->i_ino;
143 struct shmid_kernel *shp;
144
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800145 mutex_lock(&shm_ids.mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 /* remove from the list of attaches of the shm segment */
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200147 shp = shm_lock(id);
148 BUG_ON(!shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 shp->shm_lprid = current->tgid;
150 shp->shm_dtim = get_seconds();
151 shp->shm_nattch--;
152 if(shp->shm_nattch == 0 &&
Andrew Mortonb33291c2006-01-08 01:02:21 -0800153 shp->shm_perm.mode & SHM_DEST)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 shm_destroy (shp);
155 else
156 shm_unlock(shp);
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800157 mutex_unlock(&shm_ids.mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158}
159
160static int shm_mmap(struct file * file, struct vm_area_struct * vma)
161{
David Howellsb0e15192006-01-06 00:11:42 -0800162 int ret;
163
164 ret = shmem_mmap(file, vma);
165 if (ret == 0) {
166 vma->vm_ops = &shm_vm_ops;
Hugh Dickinsb78b6af2006-04-12 14:34:27 -0700167 if (!(vma->vm_flags & VM_WRITE))
168 vma->vm_flags &= ~VM_MAYWRITE;
David Howellsb0e15192006-01-06 00:11:42 -0800169 shm_inc(file->f_dentry->d_inode->i_ino);
170 }
171
172 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173}
174
175static struct file_operations shm_file_operations = {
David Howellsb0e15192006-01-06 00:11:42 -0800176 .mmap = shm_mmap,
177#ifndef CONFIG_MMU
178 .get_unmapped_area = shmem_get_unmapped_area,
179#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180};
181
182static struct vm_operations_struct shm_vm_ops = {
183 .open = shm_open, /* callback for a new vm-area open */
184 .close = shm_close, /* callback for when the vm-area is released */
185 .nopage = shmem_nopage,
Andrew Morton6ade43f2005-08-01 21:11:45 -0700186#if defined(CONFIG_NUMA) && defined(CONFIG_SHMEM)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 .set_policy = shmem_set_policy,
188 .get_policy = shmem_get_policy,
189#endif
190};
191
192static int newseg (key_t key, int shmflg, size_t size)
193{
194 int error;
195 struct shmid_kernel *shp;
196 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
197 struct file * file;
198 char name[13];
199 int id;
200
201 if (size < SHMMIN || size > shm_ctlmax)
202 return -EINVAL;
203
204 if (shm_tot + numpages >= shm_ctlall)
205 return -ENOSPC;
206
207 shp = ipc_rcu_alloc(sizeof(*shp));
208 if (!shp)
209 return -ENOMEM;
210
211 shp->shm_perm.key = key;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800212 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 shp->mlock_user = NULL;
214
215 shp->shm_perm.security = NULL;
216 error = security_shm_alloc(shp);
217 if (error) {
218 ipc_rcu_putref(shp);
219 return error;
220 }
221
222 if (shmflg & SHM_HUGETLB) {
223 /* hugetlb_zero_setup takes care of mlock user accounting */
224 file = hugetlb_zero_setup(size);
225 shp->mlock_user = current->user;
226 } else {
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800227 int acctflag = VM_ACCOUNT;
228 /*
229 * Do not allow no accounting for OVERCOMMIT_NEVER, even
230 * if it's asked for.
231 */
232 if ((shmflg & SHM_NORESERVE) &&
233 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
234 acctflag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 sprintf (name, "SYSV%08x", key);
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800236 file = shmem_file_setup(name, size, acctflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 }
238 error = PTR_ERR(file);
239 if (IS_ERR(file))
240 goto no_file;
241
242 error = -ENOSPC;
243 id = shm_addid(shp);
244 if(id == -1)
245 goto no_id;
246
247 shp->shm_cprid = current->tgid;
248 shp->shm_lprid = 0;
249 shp->shm_atim = shp->shm_dtim = 0;
250 shp->shm_ctim = get_seconds();
251 shp->shm_segsz = size;
252 shp->shm_nattch = 0;
253 shp->id = shm_buildid(id,shp->shm_perm.seq);
254 shp->shm_file = file;
255 file->f_dentry->d_inode->i_ino = shp->id;
Krishnakumar R551110a2005-10-29 18:16:45 -0700256
257 /* Hugetlb ops would have already been assigned. */
258 if (!(shmflg & SHM_HUGETLB))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 file->f_op = &shm_file_operations;
Krishnakumar R551110a2005-10-29 18:16:45 -0700260
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 shm_tot += numpages;
262 shm_unlock(shp);
263 return shp->id;
264
265no_id:
266 fput(file);
267no_file:
268 security_shm_free(shp);
269 ipc_rcu_putref(shp);
270 return error;
271}
272
273asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
274{
275 struct shmid_kernel *shp;
276 int err, id = 0;
277
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800278 mutex_lock(&shm_ids.mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 if (key == IPC_PRIVATE) {
280 err = newseg(key, shmflg, size);
281 } else if ((id = ipc_findkey(&shm_ids, key)) == -1) {
282 if (!(shmflg & IPC_CREAT))
283 err = -ENOENT;
284 else
285 err = newseg(key, shmflg, size);
286 } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
287 err = -EEXIST;
288 } else {
289 shp = shm_lock(id);
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200290 BUG_ON(shp==NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 if (shp->shm_segsz < size)
292 err = -EINVAL;
293 else if (ipcperms(&shp->shm_perm, shmflg))
294 err = -EACCES;
295 else {
296 int shmid = shm_buildid(id, shp->shm_perm.seq);
297 err = security_shm_associate(shp, shmflg);
298 if (!err)
299 err = shmid;
300 }
301 shm_unlock(shp);
302 }
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800303 mutex_unlock(&shm_ids.mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304
305 return err;
306}
307
308static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
309{
310 switch(version) {
311 case IPC_64:
312 return copy_to_user(buf, in, sizeof(*in));
313 case IPC_OLD:
314 {
315 struct shmid_ds out;
316
317 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
318 out.shm_segsz = in->shm_segsz;
319 out.shm_atime = in->shm_atime;
320 out.shm_dtime = in->shm_dtime;
321 out.shm_ctime = in->shm_ctime;
322 out.shm_cpid = in->shm_cpid;
323 out.shm_lpid = in->shm_lpid;
324 out.shm_nattch = in->shm_nattch;
325
326 return copy_to_user(buf, &out, sizeof(out));
327 }
328 default:
329 return -EINVAL;
330 }
331}
332
333struct shm_setbuf {
334 uid_t uid;
335 gid_t gid;
336 mode_t mode;
337};
338
339static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
340{
341 switch(version) {
342 case IPC_64:
343 {
344 struct shmid64_ds tbuf;
345
346 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
347 return -EFAULT;
348
349 out->uid = tbuf.shm_perm.uid;
350 out->gid = tbuf.shm_perm.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800351 out->mode = tbuf.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352
353 return 0;
354 }
355 case IPC_OLD:
356 {
357 struct shmid_ds tbuf_old;
358
359 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
360 return -EFAULT;
361
362 out->uid = tbuf_old.shm_perm.uid;
363 out->gid = tbuf_old.shm_perm.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800364 out->mode = tbuf_old.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365
366 return 0;
367 }
368 default:
369 return -EINVAL;
370 }
371}
372
373static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
374{
375 switch(version) {
376 case IPC_64:
377 return copy_to_user(buf, in, sizeof(*in));
378 case IPC_OLD:
379 {
380 struct shminfo out;
381
382 if(in->shmmax > INT_MAX)
383 out.shmmax = INT_MAX;
384 else
385 out.shmmax = (int)in->shmmax;
386
387 out.shmmin = in->shmmin;
388 out.shmmni = in->shmmni;
389 out.shmseg = in->shmseg;
390 out.shmall = in->shmall;
391
392 return copy_to_user(buf, &out, sizeof(out));
393 }
394 default:
395 return -EINVAL;
396 }
397}
398
399static void shm_get_stat(unsigned long *rss, unsigned long *swp)
400{
401 int i;
402
403 *rss = 0;
404 *swp = 0;
405
406 for (i = 0; i <= shm_ids.max_id; i++) {
407 struct shmid_kernel *shp;
408 struct inode *inode;
409
410 shp = shm_get(i);
411 if(!shp)
412 continue;
413
414 inode = shp->shm_file->f_dentry->d_inode;
415
416 if (is_file_hugepages(shp->shm_file)) {
417 struct address_space *mapping = inode->i_mapping;
418 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
419 } else {
420 struct shmem_inode_info *info = SHMEM_I(inode);
421 spin_lock(&info->lock);
422 *rss += inode->i_mapping->nrpages;
423 *swp += info->swapped;
424 spin_unlock(&info->lock);
425 }
426 }
427}
428
429asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
430{
431 struct shm_setbuf setbuf;
432 struct shmid_kernel *shp;
433 int err, version;
434
435 if (cmd < 0 || shmid < 0) {
436 err = -EINVAL;
437 goto out;
438 }
439
440 version = ipc_parse_version(&cmd);
441
442 switch (cmd) { /* replace with proc interface ? */
443 case IPC_INFO:
444 {
445 struct shminfo64 shminfo;
446
447 err = security_shm_shmctl(NULL, cmd);
448 if (err)
449 return err;
450
451 memset(&shminfo,0,sizeof(shminfo));
452 shminfo.shmmni = shminfo.shmseg = shm_ctlmni;
453 shminfo.shmmax = shm_ctlmax;
454 shminfo.shmall = shm_ctlall;
455
456 shminfo.shmmin = SHMMIN;
457 if(copy_shminfo_to_user (buf, &shminfo, version))
458 return -EFAULT;
459 /* reading a integer is always atomic */
460 err= shm_ids.max_id;
461 if(err<0)
462 err = 0;
463 goto out;
464 }
465 case SHM_INFO:
466 {
467 struct shm_info shm_info;
468
469 err = security_shm_shmctl(NULL, cmd);
470 if (err)
471 return err;
472
473 memset(&shm_info,0,sizeof(shm_info));
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800474 mutex_lock(&shm_ids.mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 shm_info.used_ids = shm_ids.in_use;
476 shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp);
477 shm_info.shm_tot = shm_tot;
478 shm_info.swap_attempts = 0;
479 shm_info.swap_successes = 0;
480 err = shm_ids.max_id;
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800481 mutex_unlock(&shm_ids.mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
483 err = -EFAULT;
484 goto out;
485 }
486
487 err = err < 0 ? 0 : err;
488 goto out;
489 }
490 case SHM_STAT:
491 case IPC_STAT:
492 {
493 struct shmid64_ds tbuf;
494 int result;
495 memset(&tbuf, 0, sizeof(tbuf));
496 shp = shm_lock(shmid);
497 if(shp==NULL) {
498 err = -EINVAL;
499 goto out;
500 } else if(cmd==SHM_STAT) {
501 err = -EINVAL;
502 if (shmid > shm_ids.max_id)
503 goto out_unlock;
504 result = shm_buildid(shmid, shp->shm_perm.seq);
505 } else {
506 err = shm_checkid(shp,shmid);
507 if(err)
508 goto out_unlock;
509 result = 0;
510 }
511 err=-EACCES;
512 if (ipcperms (&shp->shm_perm, S_IRUGO))
513 goto out_unlock;
514 err = security_shm_shmctl(shp, cmd);
515 if (err)
516 goto out_unlock;
517 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
518 tbuf.shm_segsz = shp->shm_segsz;
519 tbuf.shm_atime = shp->shm_atim;
520 tbuf.shm_dtime = shp->shm_dtim;
521 tbuf.shm_ctime = shp->shm_ctim;
522 tbuf.shm_cpid = shp->shm_cprid;
523 tbuf.shm_lpid = shp->shm_lprid;
524 if (!is_file_hugepages(shp->shm_file))
525 tbuf.shm_nattch = shp->shm_nattch;
526 else
527 tbuf.shm_nattch = file_count(shp->shm_file) - 1;
528 shm_unlock(shp);
529 if(copy_shmid_to_user (buf, &tbuf, version))
530 err = -EFAULT;
531 else
532 err = result;
533 goto out;
534 }
535 case SHM_LOCK:
536 case SHM_UNLOCK:
537 {
538 shp = shm_lock(shmid);
539 if(shp==NULL) {
540 err = -EINVAL;
541 goto out;
542 }
543 err = shm_checkid(shp,shmid);
544 if(err)
545 goto out_unlock;
546
Steve Grubb073115d2006-04-02 17:07:33 -0400547 err = audit_ipc_obj(&(shp->shm_perm));
548 if (err)
549 goto out_unlock;
550
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 if (!capable(CAP_IPC_LOCK)) {
552 err = -EPERM;
553 if (current->euid != shp->shm_perm.uid &&
554 current->euid != shp->shm_perm.cuid)
555 goto out_unlock;
556 if (cmd == SHM_LOCK &&
557 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
558 goto out_unlock;
559 }
560
561 err = security_shm_shmctl(shp, cmd);
562 if (err)
563 goto out_unlock;
564
565 if(cmd==SHM_LOCK) {
566 struct user_struct * user = current->user;
567 if (!is_file_hugepages(shp->shm_file)) {
568 err = shmem_lock(shp->shm_file, 1, user);
569 if (!err) {
Andrew Mortonb33291c2006-01-08 01:02:21 -0800570 shp->shm_perm.mode |= SHM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 shp->mlock_user = user;
572 }
573 }
574 } else if (!is_file_hugepages(shp->shm_file)) {
575 shmem_lock(shp->shm_file, 0, shp->mlock_user);
Andrew Mortonb33291c2006-01-08 01:02:21 -0800576 shp->shm_perm.mode &= ~SHM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 shp->mlock_user = NULL;
578 }
579 shm_unlock(shp);
580 goto out;
581 }
582 case IPC_RMID:
583 {
584 /*
585 * We cannot simply remove the file. The SVID states
586 * that the block remains until the last person
587 * detaches from it, then is deleted. A shmat() on
588 * an RMID segment is legal in older Linux and if
589 * we change it apps break...
590 *
591 * Instead we set a destroyed flag, and then blow
592 * the name away when the usage hits zero.
593 */
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800594 mutex_lock(&shm_ids.mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 shp = shm_lock(shmid);
596 err = -EINVAL;
597 if (shp == NULL)
598 goto out_up;
599 err = shm_checkid(shp, shmid);
600 if(err)
601 goto out_unlock_up;
602
Steve Grubb073115d2006-04-02 17:07:33 -0400603 err = audit_ipc_obj(&(shp->shm_perm));
604 if (err)
605 goto out_unlock_up;
606
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 if (current->euid != shp->shm_perm.uid &&
608 current->euid != shp->shm_perm.cuid &&
609 !capable(CAP_SYS_ADMIN)) {
610 err=-EPERM;
611 goto out_unlock_up;
612 }
613
614 err = security_shm_shmctl(shp, cmd);
615 if (err)
616 goto out_unlock_up;
617
618 if (shp->shm_nattch){
Andrew Mortonb33291c2006-01-08 01:02:21 -0800619 shp->shm_perm.mode |= SHM_DEST;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 /* Do not find it any more */
621 shp->shm_perm.key = IPC_PRIVATE;
622 shm_unlock(shp);
623 } else
624 shm_destroy (shp);
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800625 mutex_unlock(&shm_ids.mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 goto out;
627 }
628
629 case IPC_SET:
630 {
631 if (copy_shmid_from_user (&setbuf, buf, version)) {
632 err = -EFAULT;
633 goto out;
634 }
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800635 mutex_lock(&shm_ids.mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 shp = shm_lock(shmid);
637 err=-EINVAL;
638 if(shp==NULL)
639 goto out_up;
640 err = shm_checkid(shp,shmid);
641 if(err)
642 goto out_unlock_up;
Steve Grubb073115d2006-04-02 17:07:33 -0400643 err = audit_ipc_obj(&(shp->shm_perm));
644 if (err)
645 goto out_unlock_up;
Linda Knippersac032212006-05-16 22:03:48 -0400646 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
Steve Grubb073115d2006-04-02 17:07:33 -0400647 if (err)
648 goto out_unlock_up;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 err=-EPERM;
650 if (current->euid != shp->shm_perm.uid &&
651 current->euid != shp->shm_perm.cuid &&
652 !capable(CAP_SYS_ADMIN)) {
653 goto out_unlock_up;
654 }
655
656 err = security_shm_shmctl(shp, cmd);
657 if (err)
658 goto out_unlock_up;
659
660 shp->shm_perm.uid = setbuf.uid;
661 shp->shm_perm.gid = setbuf.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800662 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 | (setbuf.mode & S_IRWXUGO);
664 shp->shm_ctim = get_seconds();
665 break;
666 }
667
668 default:
669 err = -EINVAL;
670 goto out;
671 }
672
673 err = 0;
674out_unlock_up:
675 shm_unlock(shp);
676out_up:
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800677 mutex_unlock(&shm_ids.mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 goto out;
679out_unlock:
680 shm_unlock(shp);
681out:
682 return err;
683}
684
685/*
686 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
687 *
688 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
689 * "raddr" thing points to kernel space, and there has to be a wrapper around
690 * this.
691 */
692long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
693{
694 struct shmid_kernel *shp;
695 unsigned long addr;
696 unsigned long size;
697 struct file * file;
698 int err;
699 unsigned long flags;
700 unsigned long prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 int acc_mode;
702 void *user_addr;
703
704 if (shmid < 0) {
705 err = -EINVAL;
706 goto out;
707 } else if ((addr = (ulong)shmaddr)) {
708 if (addr & (SHMLBA-1)) {
709 if (shmflg & SHM_RND)
710 addr &= ~(SHMLBA-1); /* round down */
711 else
712#ifndef __ARCH_FORCE_SHMLBA
713 if (addr & ~PAGE_MASK)
714#endif
715 return -EINVAL;
716 }
717 flags = MAP_SHARED | MAP_FIXED;
718 } else {
719 if ((shmflg & SHM_REMAP))
720 return -EINVAL;
721
722 flags = MAP_SHARED;
723 }
724
725 if (shmflg & SHM_RDONLY) {
726 prot = PROT_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 acc_mode = S_IRUGO;
728 } else {
729 prot = PROT_READ | PROT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 acc_mode = S_IRUGO | S_IWUGO;
731 }
732 if (shmflg & SHM_EXEC) {
733 prot |= PROT_EXEC;
734 acc_mode |= S_IXUGO;
735 }
736
737 /*
738 * We cannot rely on the fs check since SYSV IPC does have an
739 * additional creator id...
740 */
741 shp = shm_lock(shmid);
742 if(shp == NULL) {
743 err = -EINVAL;
744 goto out;
745 }
746 err = shm_checkid(shp,shmid);
747 if (err) {
748 shm_unlock(shp);
749 goto out;
750 }
751 if (ipcperms(&shp->shm_perm, acc_mode)) {
752 shm_unlock(shp);
753 err = -EACCES;
754 goto out;
755 }
756
757 err = security_shm_shmat(shp, shmaddr, shmflg);
758 if (err) {
759 shm_unlock(shp);
760 return err;
761 }
762
763 file = shp->shm_file;
764 size = i_size_read(file->f_dentry->d_inode);
765 shp->shm_nattch++;
766 shm_unlock(shp);
767
768 down_write(&current->mm->mmap_sem);
769 if (addr && !(shmflg & SHM_REMAP)) {
770 user_addr = ERR_PTR(-EINVAL);
771 if (find_vma_intersection(current->mm, addr, addr + size))
772 goto invalid;
773 /*
774 * If shm segment goes below stack, make sure there is some
775 * space left for the stack to grow (at least 4 pages).
776 */
777 if (addr < current->mm->start_stack &&
778 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
779 goto invalid;
780 }
781
782 user_addr = (void*) do_mmap (file, addr, size, prot, flags, 0);
783
784invalid:
785 up_write(&current->mm->mmap_sem);
786
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800787 mutex_lock(&shm_ids.mutex);
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200788 shp = shm_lock(shmid);
789 BUG_ON(!shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 shp->shm_nattch--;
791 if(shp->shm_nattch == 0 &&
Andrew Mortonb33291c2006-01-08 01:02:21 -0800792 shp->shm_perm.mode & SHM_DEST)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 shm_destroy (shp);
794 else
795 shm_unlock(shp);
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800796 mutex_unlock(&shm_ids.mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797
798 *raddr = (unsigned long) user_addr;
799 err = 0;
800 if (IS_ERR(user_addr))
801 err = PTR_ERR(user_addr);
802out:
803 return err;
804}
805
Stephen Rothwell7d87e142005-05-01 08:59:12 -0700806asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
807{
808 unsigned long ret;
809 long err;
810
811 err = do_shmat(shmid, shmaddr, shmflg, &ret);
812 if (err)
813 return err;
814 force_successful_syscall_return();
815 return (long)ret;
816}
817
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818/*
819 * detach and kill segment if marked destroyed.
820 * The work is done in shm_close.
821 */
822asmlinkage long sys_shmdt(char __user *shmaddr)
823{
824 struct mm_struct *mm = current->mm;
825 struct vm_area_struct *vma, *next;
826 unsigned long addr = (unsigned long)shmaddr;
827 loff_t size = 0;
828 int retval = -EINVAL;
829
Hugh Dickinsdf1e2fb2006-03-24 03:18:06 -0800830 if (addr & ~PAGE_MASK)
831 return retval;
832
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 down_write(&mm->mmap_sem);
834
835 /*
836 * This function tries to be smart and unmap shm segments that
837 * were modified by partial mlock or munmap calls:
838 * - It first determines the size of the shm segment that should be
839 * unmapped: It searches for a vma that is backed by shm and that
840 * started at address shmaddr. It records it's size and then unmaps
841 * it.
842 * - Then it unmaps all shm vmas that started at shmaddr and that
843 * are within the initially determined size.
844 * Errors from do_munmap are ignored: the function only fails if
845 * it's called with invalid parameters or if it's called to unmap
846 * a part of a vma. Both calls in this function are for full vmas,
847 * the parameters are directly copied from the vma itself and always
848 * valid - therefore do_munmap cannot fail. (famous last words?)
849 */
850 /*
851 * If it had been mremap()'d, the starting address would not
852 * match the usual checks anyway. So assume all vma's are
853 * above the starting address given.
854 */
855 vma = find_vma(mm, addr);
856
857 while (vma) {
858 next = vma->vm_next;
859
860 /*
861 * Check if the starting address would match, i.e. it's
862 * a fragment created by mprotect() and/or munmap(), or it
863 * otherwise it starts at this address with no hassles.
864 */
865 if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
866 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
867
868
869 size = vma->vm_file->f_dentry->d_inode->i_size;
870 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
871 /*
872 * We discovered the size of the shm segment, so
873 * break out of here and fall through to the next
874 * loop that uses the size information to stop
875 * searching for matching vma's.
876 */
877 retval = 0;
878 vma = next;
879 break;
880 }
881 vma = next;
882 }
883
884 /*
885 * We need look no further than the maximum address a fragment
886 * could possibly have landed at. Also cast things to loff_t to
887 * prevent overflows and make comparisions vs. equal-width types.
888 */
KAMEZAWA Hiroyuki8e367092006-02-10 01:51:12 -0800889 size = PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
891 next = vma->vm_next;
892
893 /* finding a matching vma now does not alter retval */
894 if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
895 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
896
897 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
898 vma = next;
899 }
900
901 up_write(&mm->mmap_sem);
902 return retval;
903}
904
905#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -0700906static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907{
Mike Waychison19b49462005-09-06 15:17:10 -0700908 struct shmid_kernel *shp = it;
909 char *format;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
912#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 -0700913
Mike Waychison19b49462005-09-06 15:17:10 -0700914 if (sizeof(size_t) <= sizeof(int))
915 format = SMALL_STRING;
916 else
917 format = BIG_STRING;
918 return seq_printf(s, format,
919 shp->shm_perm.key,
920 shp->id,
Andrew Mortonb33291c2006-01-08 01:02:21 -0800921 shp->shm_perm.mode,
Mike Waychison19b49462005-09-06 15:17:10 -0700922 shp->shm_segsz,
923 shp->shm_cprid,
924 shp->shm_lprid,
925 is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch,
926 shp->shm_perm.uid,
927 shp->shm_perm.gid,
928 shp->shm_perm.cuid,
929 shp->shm_perm.cgid,
930 shp->shm_atim,
931 shp->shm_dtim,
932 shp->shm_ctim);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933}
934#endif