Drop some headers from mm.h
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / ipc / shm.c
blobb8884c288ecc868042921bba34f094d81586a280
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.
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>
16 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
19 * namespaces support
20 * OpenVZ, SWsoft Inc.
21 * Pavel Emelianov <xemul@openvz.org>
24 #include <linux/slab.h>
25 #include <linux/mm.h>
26 #include <linux/hugetlb.h>
27 #include <linux/shm.h>
28 #include <linux/init.h>
29 #include <linux/file.h>
30 #include <linux/mman.h>
31 #include <linux/shmem_fs.h>
32 #include <linux/security.h>
33 #include <linux/syscalls.h>
34 #include <linux/audit.h>
35 #include <linux/capability.h>
36 #include <linux/ptrace.h>
37 #include <linux/seq_file.h>
38 #include <linux/mutex.h>
39 #include <linux/nsproxy.h>
40 #include <linux/mount.h>
42 #include <asm/uaccess.h>
44 #include "util.h"
46 struct shm_file_data {
47 int id;
48 struct ipc_namespace *ns;
49 struct file *file;
50 const struct vm_operations_struct *vm_ops;
53 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
55 static const struct file_operations shm_file_operations;
56 static struct vm_operations_struct shm_vm_ops;
58 static struct ipc_ids init_shm_ids;
60 #define shm_ids(ns) (*((ns)->ids[IPC_SHM_IDS]))
62 #define shm_lock(ns, id) \
63 ((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id))
64 #define shm_unlock(shp) \
65 ipc_unlock(&(shp)->shm_perm)
66 #define shm_get(ns, id) \
67 ((struct shmid_kernel*)ipc_get(&shm_ids(ns),id))
68 #define shm_buildid(ns, id, seq) \
69 ipc_buildid(&shm_ids(ns), id, seq)
71 static int newseg (struct ipc_namespace *ns, key_t key,
72 int shmflg, size_t size);
73 static void shm_open(struct vm_area_struct *vma);
74 static void shm_close(struct vm_area_struct *vma);
75 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
76 #ifdef CONFIG_PROC_FS
77 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
78 #endif
80 static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
82 ns->ids[IPC_SHM_IDS] = ids;
83 ns->shm_ctlmax = SHMMAX;
84 ns->shm_ctlall = SHMALL;
85 ns->shm_ctlmni = SHMMNI;
86 ns->shm_tot = 0;
87 ipc_init_ids(ids, 1);
90 static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
92 if (shp->shm_nattch){
93 shp->shm_perm.mode |= SHM_DEST;
94 /* Do not find it any more */
95 shp->shm_perm.key = IPC_PRIVATE;
96 shm_unlock(shp);
97 } else
98 shm_destroy(ns, shp);
101 int shm_init_ns(struct ipc_namespace *ns)
103 struct ipc_ids *ids;
105 ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
106 if (ids == NULL)
107 return -ENOMEM;
109 __shm_init_ns(ns, ids);
110 return 0;
113 void shm_exit_ns(struct ipc_namespace *ns)
115 int i;
116 struct shmid_kernel *shp;
118 mutex_lock(&shm_ids(ns).mutex);
119 for (i = 0; i <= shm_ids(ns).max_id; i++) {
120 shp = shm_lock(ns, i);
121 if (shp == NULL)
122 continue;
124 do_shm_rmid(ns, shp);
126 mutex_unlock(&shm_ids(ns).mutex);
128 ipc_fini_ids(ns->ids[IPC_SHM_IDS]);
129 kfree(ns->ids[IPC_SHM_IDS]);
130 ns->ids[IPC_SHM_IDS] = NULL;
133 void __init shm_init (void)
135 __shm_init_ns(&init_ipc_ns, &init_shm_ids);
136 ipc_init_proc_interface("sysvipc/shm",
137 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
138 IPC_SHM_IDS, sysvipc_shm_proc_show);
141 static inline int shm_checkid(struct ipc_namespace *ns,
142 struct shmid_kernel *s, int id)
144 if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
145 return -EIDRM;
146 return 0;
149 static inline struct shmid_kernel *shm_rmid(struct ipc_namespace *ns, int id)
151 return (struct shmid_kernel *)ipc_rmid(&shm_ids(ns), id);
154 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
156 return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
161 /* This is called by fork, once for every shm attach. */
162 static void shm_open(struct vm_area_struct *vma)
164 struct file *file = vma->vm_file;
165 struct shm_file_data *sfd = shm_file_data(file);
166 struct shmid_kernel *shp;
168 shp = shm_lock(sfd->ns, sfd->id);
169 BUG_ON(!shp);
170 shp->shm_atim = get_seconds();
171 shp->shm_lprid = current->tgid;
172 shp->shm_nattch++;
173 shm_unlock(shp);
177 * shm_destroy - free the struct shmid_kernel
179 * @shp: struct to free
181 * It has to be called with shp and shm_ids.mutex locked,
182 * but returns with shp unlocked and freed.
184 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
186 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
187 shm_rmid(ns, shp->id);
188 shm_unlock(shp);
189 if (!is_file_hugepages(shp->shm_file))
190 shmem_lock(shp->shm_file, 0, shp->mlock_user);
191 else
192 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
193 shp->mlock_user);
194 fput (shp->shm_file);
195 security_shm_free(shp);
196 ipc_rcu_putref(shp);
200 * remove the attach descriptor vma.
201 * free memory for segment if it is marked destroyed.
202 * The descriptor has already been removed from the current->mm->mmap list
203 * and will later be kfree()d.
205 static void shm_close(struct vm_area_struct *vma)
207 struct file * file = vma->vm_file;
208 struct shm_file_data *sfd = shm_file_data(file);
209 struct shmid_kernel *shp;
210 struct ipc_namespace *ns = sfd->ns;
212 mutex_lock(&shm_ids(ns).mutex);
213 /* remove from the list of attaches of the shm segment */
214 shp = shm_lock(ns, sfd->id);
215 BUG_ON(!shp);
216 shp->shm_lprid = current->tgid;
217 shp->shm_dtim = get_seconds();
218 shp->shm_nattch--;
219 if(shp->shm_nattch == 0 &&
220 shp->shm_perm.mode & SHM_DEST)
221 shm_destroy(ns, shp);
222 else
223 shm_unlock(shp);
224 mutex_unlock(&shm_ids(ns).mutex);
227 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
229 struct file *file = vma->vm_file;
230 struct shm_file_data *sfd = shm_file_data(file);
232 return sfd->vm_ops->fault(vma, vmf);
235 #ifdef CONFIG_NUMA
236 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
238 struct file *file = vma->vm_file;
239 struct shm_file_data *sfd = shm_file_data(file);
240 int err = 0;
241 if (sfd->vm_ops->set_policy)
242 err = sfd->vm_ops->set_policy(vma, new);
243 return err;
246 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
247 unsigned long addr)
249 struct file *file = vma->vm_file;
250 struct shm_file_data *sfd = shm_file_data(file);
251 struct mempolicy *pol = NULL;
253 if (sfd->vm_ops->get_policy)
254 pol = sfd->vm_ops->get_policy(vma, addr);
255 else if (vma->vm_policy)
256 pol = vma->vm_policy;
257 else
258 pol = current->mempolicy;
259 return pol;
261 #endif
263 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
265 struct shm_file_data *sfd = shm_file_data(file);
266 int ret;
268 ret = sfd->file->f_op->mmap(sfd->file, vma);
269 if (ret != 0)
270 return ret;
271 sfd->vm_ops = vma->vm_ops;
272 #ifdef CONFIG_MMU
273 BUG_ON(!sfd->vm_ops->fault);
274 #endif
275 vma->vm_ops = &shm_vm_ops;
276 shm_open(vma);
278 return ret;
281 static int shm_release(struct inode *ino, struct file *file)
283 struct shm_file_data *sfd = shm_file_data(file);
285 put_ipc_ns(sfd->ns);
286 shm_file_data(file) = NULL;
287 kfree(sfd);
288 return 0;
291 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
293 int (*fsync) (struct file *, struct dentry *, int datasync);
294 struct shm_file_data *sfd = shm_file_data(file);
295 int ret = -EINVAL;
297 fsync = sfd->file->f_op->fsync;
298 if (fsync)
299 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
300 return ret;
303 static unsigned long shm_get_unmapped_area(struct file *file,
304 unsigned long addr, unsigned long len, unsigned long pgoff,
305 unsigned long flags)
307 struct shm_file_data *sfd = shm_file_data(file);
308 return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
311 int is_file_shm_hugepages(struct file *file)
313 int ret = 0;
315 if (file->f_op == &shm_file_operations) {
316 struct shm_file_data *sfd;
317 sfd = shm_file_data(file);
318 ret = is_file_hugepages(sfd->file);
320 return ret;
323 static const struct file_operations shm_file_operations = {
324 .mmap = shm_mmap,
325 .fsync = shm_fsync,
326 .release = shm_release,
327 .get_unmapped_area = shm_get_unmapped_area,
330 static struct vm_operations_struct shm_vm_ops = {
331 .open = shm_open, /* callback for a new vm-area open */
332 .close = shm_close, /* callback for when the vm-area is released */
333 .fault = shm_fault,
334 #if defined(CONFIG_NUMA)
335 .set_policy = shm_set_policy,
336 .get_policy = shm_get_policy,
337 #endif
340 static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
342 int error;
343 struct shmid_kernel *shp;
344 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
345 struct file * file;
346 char name[13];
347 int id;
349 if (size < SHMMIN || size > ns->shm_ctlmax)
350 return -EINVAL;
352 if (ns->shm_tot + numpages > ns->shm_ctlall)
353 return -ENOSPC;
355 shp = ipc_rcu_alloc(sizeof(*shp));
356 if (!shp)
357 return -ENOMEM;
359 shp->shm_perm.key = key;
360 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
361 shp->mlock_user = NULL;
363 shp->shm_perm.security = NULL;
364 error = security_shm_alloc(shp);
365 if (error) {
366 ipc_rcu_putref(shp);
367 return error;
370 sprintf (name, "SYSV%08x", key);
371 if (shmflg & SHM_HUGETLB) {
372 /* hugetlb_file_setup takes care of mlock user accounting */
373 file = hugetlb_file_setup(name, size);
374 shp->mlock_user = current->user;
375 } else {
376 int acctflag = VM_ACCOUNT;
378 * Do not allow no accounting for OVERCOMMIT_NEVER, even
379 * if it's asked for.
381 if ((shmflg & SHM_NORESERVE) &&
382 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
383 acctflag = 0;
384 file = shmem_file_setup(name, size, acctflag);
386 error = PTR_ERR(file);
387 if (IS_ERR(file))
388 goto no_file;
390 error = -ENOSPC;
391 id = shm_addid(ns, shp);
392 if(id == -1)
393 goto no_id;
395 shp->shm_cprid = current->tgid;
396 shp->shm_lprid = 0;
397 shp->shm_atim = shp->shm_dtim = 0;
398 shp->shm_ctim = get_seconds();
399 shp->shm_segsz = size;
400 shp->shm_nattch = 0;
401 shp->id = shm_buildid(ns, id, shp->shm_perm.seq);
402 shp->shm_file = file;
404 * shmid gets reported as "inode#" in /proc/pid/maps.
405 * proc-ps tools use this. Changing this will break them.
407 file->f_dentry->d_inode->i_ino = shp->id;
409 ns->shm_tot += numpages;
410 shm_unlock(shp);
411 return shp->id;
413 no_id:
414 fput(file);
415 no_file:
416 security_shm_free(shp);
417 ipc_rcu_putref(shp);
418 return error;
421 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
423 struct shmid_kernel *shp;
424 int err, id = 0;
425 struct ipc_namespace *ns;
427 ns = current->nsproxy->ipc_ns;
429 mutex_lock(&shm_ids(ns).mutex);
430 if (key == IPC_PRIVATE) {
431 err = newseg(ns, key, shmflg, size);
432 } else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
433 if (!(shmflg & IPC_CREAT))
434 err = -ENOENT;
435 else
436 err = newseg(ns, key, shmflg, size);
437 } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
438 err = -EEXIST;
439 } else {
440 shp = shm_lock(ns, id);
441 BUG_ON(shp==NULL);
442 if (shp->shm_segsz < size)
443 err = -EINVAL;
444 else if (ipcperms(&shp->shm_perm, shmflg))
445 err = -EACCES;
446 else {
447 int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
448 err = security_shm_associate(shp, shmflg);
449 if (!err)
450 err = shmid;
452 shm_unlock(shp);
454 mutex_unlock(&shm_ids(ns).mutex);
456 return err;
459 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
461 switch(version) {
462 case IPC_64:
463 return copy_to_user(buf, in, sizeof(*in));
464 case IPC_OLD:
466 struct shmid_ds out;
468 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
469 out.shm_segsz = in->shm_segsz;
470 out.shm_atime = in->shm_atime;
471 out.shm_dtime = in->shm_dtime;
472 out.shm_ctime = in->shm_ctime;
473 out.shm_cpid = in->shm_cpid;
474 out.shm_lpid = in->shm_lpid;
475 out.shm_nattch = in->shm_nattch;
477 return copy_to_user(buf, &out, sizeof(out));
479 default:
480 return -EINVAL;
484 struct shm_setbuf {
485 uid_t uid;
486 gid_t gid;
487 mode_t mode;
490 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
492 switch(version) {
493 case IPC_64:
495 struct shmid64_ds tbuf;
497 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
498 return -EFAULT;
500 out->uid = tbuf.shm_perm.uid;
501 out->gid = tbuf.shm_perm.gid;
502 out->mode = tbuf.shm_perm.mode;
504 return 0;
506 case IPC_OLD:
508 struct shmid_ds tbuf_old;
510 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
511 return -EFAULT;
513 out->uid = tbuf_old.shm_perm.uid;
514 out->gid = tbuf_old.shm_perm.gid;
515 out->mode = tbuf_old.shm_perm.mode;
517 return 0;
519 default:
520 return -EINVAL;
524 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
526 switch(version) {
527 case IPC_64:
528 return copy_to_user(buf, in, sizeof(*in));
529 case IPC_OLD:
531 struct shminfo out;
533 if(in->shmmax > INT_MAX)
534 out.shmmax = INT_MAX;
535 else
536 out.shmmax = (int)in->shmmax;
538 out.shmmin = in->shmmin;
539 out.shmmni = in->shmmni;
540 out.shmseg = in->shmseg;
541 out.shmall = in->shmall;
543 return copy_to_user(buf, &out, sizeof(out));
545 default:
546 return -EINVAL;
550 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
551 unsigned long *swp)
553 int i;
555 *rss = 0;
556 *swp = 0;
558 for (i = 0; i <= shm_ids(ns).max_id; i++) {
559 struct shmid_kernel *shp;
560 struct inode *inode;
562 shp = shm_get(ns, i);
563 if(!shp)
564 continue;
566 inode = shp->shm_file->f_path.dentry->d_inode;
568 if (is_file_hugepages(shp->shm_file)) {
569 struct address_space *mapping = inode->i_mapping;
570 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
571 } else {
572 struct shmem_inode_info *info = SHMEM_I(inode);
573 spin_lock(&info->lock);
574 *rss += inode->i_mapping->nrpages;
575 *swp += info->swapped;
576 spin_unlock(&info->lock);
581 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
583 struct shm_setbuf setbuf;
584 struct shmid_kernel *shp;
585 int err, version;
586 struct ipc_namespace *ns;
588 if (cmd < 0 || shmid < 0) {
589 err = -EINVAL;
590 goto out;
593 version = ipc_parse_version(&cmd);
594 ns = current->nsproxy->ipc_ns;
596 switch (cmd) { /* replace with proc interface ? */
597 case IPC_INFO:
599 struct shminfo64 shminfo;
601 err = security_shm_shmctl(NULL, cmd);
602 if (err)
603 return err;
605 memset(&shminfo,0,sizeof(shminfo));
606 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
607 shminfo.shmmax = ns->shm_ctlmax;
608 shminfo.shmall = ns->shm_ctlall;
610 shminfo.shmmin = SHMMIN;
611 if(copy_shminfo_to_user (buf, &shminfo, version))
612 return -EFAULT;
613 /* reading a integer is always atomic */
614 err= shm_ids(ns).max_id;
615 if(err<0)
616 err = 0;
617 goto out;
619 case SHM_INFO:
621 struct shm_info shm_info;
623 err = security_shm_shmctl(NULL, cmd);
624 if (err)
625 return err;
627 memset(&shm_info,0,sizeof(shm_info));
628 mutex_lock(&shm_ids(ns).mutex);
629 shm_info.used_ids = shm_ids(ns).in_use;
630 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
631 shm_info.shm_tot = ns->shm_tot;
632 shm_info.swap_attempts = 0;
633 shm_info.swap_successes = 0;
634 err = shm_ids(ns).max_id;
635 mutex_unlock(&shm_ids(ns).mutex);
636 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
637 err = -EFAULT;
638 goto out;
641 err = err < 0 ? 0 : err;
642 goto out;
644 case SHM_STAT:
645 case IPC_STAT:
647 struct shmid64_ds tbuf;
648 int result;
649 memset(&tbuf, 0, sizeof(tbuf));
650 shp = shm_lock(ns, shmid);
651 if(shp==NULL) {
652 err = -EINVAL;
653 goto out;
654 } else if(cmd==SHM_STAT) {
655 err = -EINVAL;
656 if (shmid > shm_ids(ns).max_id)
657 goto out_unlock;
658 result = shm_buildid(ns, shmid, shp->shm_perm.seq);
659 } else {
660 err = shm_checkid(ns, shp,shmid);
661 if(err)
662 goto out_unlock;
663 result = 0;
665 err=-EACCES;
666 if (ipcperms (&shp->shm_perm, S_IRUGO))
667 goto out_unlock;
668 err = security_shm_shmctl(shp, cmd);
669 if (err)
670 goto out_unlock;
671 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
672 tbuf.shm_segsz = shp->shm_segsz;
673 tbuf.shm_atime = shp->shm_atim;
674 tbuf.shm_dtime = shp->shm_dtim;
675 tbuf.shm_ctime = shp->shm_ctim;
676 tbuf.shm_cpid = shp->shm_cprid;
677 tbuf.shm_lpid = shp->shm_lprid;
678 tbuf.shm_nattch = shp->shm_nattch;
679 shm_unlock(shp);
680 if(copy_shmid_to_user (buf, &tbuf, version))
681 err = -EFAULT;
682 else
683 err = result;
684 goto out;
686 case SHM_LOCK:
687 case SHM_UNLOCK:
689 shp = shm_lock(ns, shmid);
690 if(shp==NULL) {
691 err = -EINVAL;
692 goto out;
694 err = shm_checkid(ns, shp,shmid);
695 if(err)
696 goto out_unlock;
698 err = audit_ipc_obj(&(shp->shm_perm));
699 if (err)
700 goto out_unlock;
702 if (!capable(CAP_IPC_LOCK)) {
703 err = -EPERM;
704 if (current->euid != shp->shm_perm.uid &&
705 current->euid != shp->shm_perm.cuid)
706 goto out_unlock;
707 if (cmd == SHM_LOCK &&
708 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
709 goto out_unlock;
712 err = security_shm_shmctl(shp, cmd);
713 if (err)
714 goto out_unlock;
716 if(cmd==SHM_LOCK) {
717 struct user_struct * user = current->user;
718 if (!is_file_hugepages(shp->shm_file)) {
719 err = shmem_lock(shp->shm_file, 1, user);
720 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
721 shp->shm_perm.mode |= SHM_LOCKED;
722 shp->mlock_user = user;
725 } else if (!is_file_hugepages(shp->shm_file)) {
726 shmem_lock(shp->shm_file, 0, shp->mlock_user);
727 shp->shm_perm.mode &= ~SHM_LOCKED;
728 shp->mlock_user = NULL;
730 shm_unlock(shp);
731 goto out;
733 case IPC_RMID:
736 * We cannot simply remove the file. The SVID states
737 * that the block remains until the last person
738 * detaches from it, then is deleted. A shmat() on
739 * an RMID segment is legal in older Linux and if
740 * we change it apps break...
742 * Instead we set a destroyed flag, and then blow
743 * the name away when the usage hits zero.
745 mutex_lock(&shm_ids(ns).mutex);
746 shp = shm_lock(ns, shmid);
747 err = -EINVAL;
748 if (shp == NULL)
749 goto out_up;
750 err = shm_checkid(ns, shp, shmid);
751 if(err)
752 goto out_unlock_up;
754 err = audit_ipc_obj(&(shp->shm_perm));
755 if (err)
756 goto out_unlock_up;
758 if (current->euid != shp->shm_perm.uid &&
759 current->euid != shp->shm_perm.cuid &&
760 !capable(CAP_SYS_ADMIN)) {
761 err=-EPERM;
762 goto out_unlock_up;
765 err = security_shm_shmctl(shp, cmd);
766 if (err)
767 goto out_unlock_up;
769 do_shm_rmid(ns, shp);
770 mutex_unlock(&shm_ids(ns).mutex);
771 goto out;
774 case IPC_SET:
776 if (copy_shmid_from_user (&setbuf, buf, version)) {
777 err = -EFAULT;
778 goto out;
780 mutex_lock(&shm_ids(ns).mutex);
781 shp = shm_lock(ns, shmid);
782 err=-EINVAL;
783 if(shp==NULL)
784 goto out_up;
785 err = shm_checkid(ns, shp,shmid);
786 if(err)
787 goto out_unlock_up;
788 err = audit_ipc_obj(&(shp->shm_perm));
789 if (err)
790 goto out_unlock_up;
791 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
792 if (err)
793 goto out_unlock_up;
794 err=-EPERM;
795 if (current->euid != shp->shm_perm.uid &&
796 current->euid != shp->shm_perm.cuid &&
797 !capable(CAP_SYS_ADMIN)) {
798 goto out_unlock_up;
801 err = security_shm_shmctl(shp, cmd);
802 if (err)
803 goto out_unlock_up;
805 shp->shm_perm.uid = setbuf.uid;
806 shp->shm_perm.gid = setbuf.gid;
807 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
808 | (setbuf.mode & S_IRWXUGO);
809 shp->shm_ctim = get_seconds();
810 break;
813 default:
814 err = -EINVAL;
815 goto out;
818 err = 0;
819 out_unlock_up:
820 shm_unlock(shp);
821 out_up:
822 mutex_unlock(&shm_ids(ns).mutex);
823 goto out;
824 out_unlock:
825 shm_unlock(shp);
826 out:
827 return err;
831 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
833 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
834 * "raddr" thing points to kernel space, and there has to be a wrapper around
835 * this.
837 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
839 struct shmid_kernel *shp;
840 unsigned long addr;
841 unsigned long size;
842 struct file * file;
843 int err;
844 unsigned long flags;
845 unsigned long prot;
846 int acc_mode;
847 unsigned long user_addr;
848 struct ipc_namespace *ns;
849 struct shm_file_data *sfd;
850 struct path path;
851 mode_t f_mode;
853 err = -EINVAL;
854 if (shmid < 0)
855 goto out;
856 else if ((addr = (ulong)shmaddr)) {
857 if (addr & (SHMLBA-1)) {
858 if (shmflg & SHM_RND)
859 addr &= ~(SHMLBA-1); /* round down */
860 else
861 #ifndef __ARCH_FORCE_SHMLBA
862 if (addr & ~PAGE_MASK)
863 #endif
864 goto out;
866 flags = MAP_SHARED | MAP_FIXED;
867 } else {
868 if ((shmflg & SHM_REMAP))
869 goto out;
871 flags = MAP_SHARED;
874 if (shmflg & SHM_RDONLY) {
875 prot = PROT_READ;
876 acc_mode = S_IRUGO;
877 f_mode = FMODE_READ;
878 } else {
879 prot = PROT_READ | PROT_WRITE;
880 acc_mode = S_IRUGO | S_IWUGO;
881 f_mode = FMODE_READ | FMODE_WRITE;
883 if (shmflg & SHM_EXEC) {
884 prot |= PROT_EXEC;
885 acc_mode |= S_IXUGO;
889 * We cannot rely on the fs check since SYSV IPC does have an
890 * additional creator id...
892 ns = current->nsproxy->ipc_ns;
893 shp = shm_lock(ns, shmid);
894 if(shp == NULL)
895 goto out;
897 err = shm_checkid(ns, shp,shmid);
898 if (err)
899 goto out_unlock;
901 err = -EACCES;
902 if (ipcperms(&shp->shm_perm, acc_mode))
903 goto out_unlock;
905 err = security_shm_shmat(shp, shmaddr, shmflg);
906 if (err)
907 goto out_unlock;
909 path.dentry = dget(shp->shm_file->f_path.dentry);
910 path.mnt = mntget(shp->shm_file->f_path.mnt);
911 shp->shm_nattch++;
912 size = i_size_read(path.dentry->d_inode);
913 shm_unlock(shp);
915 err = -ENOMEM;
916 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
917 if (!sfd)
918 goto out_put_path;
920 err = -ENOMEM;
921 file = get_empty_filp();
922 if (!file)
923 goto out_free;
925 file->f_op = &shm_file_operations;
926 file->private_data = sfd;
927 file->f_path = path;
928 file->f_mapping = shp->shm_file->f_mapping;
929 file->f_mode = f_mode;
930 sfd->id = shp->id;
931 sfd->ns = get_ipc_ns(ns);
932 sfd->file = shp->shm_file;
933 sfd->vm_ops = NULL;
935 down_write(&current->mm->mmap_sem);
936 if (addr && !(shmflg & SHM_REMAP)) {
937 err = -EINVAL;
938 if (find_vma_intersection(current->mm, addr, addr + size))
939 goto invalid;
941 * If shm segment goes below stack, make sure there is some
942 * space left for the stack to grow (at least 4 pages).
944 if (addr < current->mm->start_stack &&
945 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
946 goto invalid;
949 user_addr = do_mmap (file, addr, size, prot, flags, 0);
950 *raddr = user_addr;
951 err = 0;
952 if (IS_ERR_VALUE(user_addr))
953 err = (long)user_addr;
954 invalid:
955 up_write(&current->mm->mmap_sem);
957 fput(file);
959 out_nattch:
960 mutex_lock(&shm_ids(ns).mutex);
961 shp = shm_lock(ns, shmid);
962 BUG_ON(!shp);
963 shp->shm_nattch--;
964 if(shp->shm_nattch == 0 &&
965 shp->shm_perm.mode & SHM_DEST)
966 shm_destroy(ns, shp);
967 else
968 shm_unlock(shp);
969 mutex_unlock(&shm_ids(ns).mutex);
971 out:
972 return err;
974 out_unlock:
975 shm_unlock(shp);
976 goto out;
978 out_free:
979 kfree(sfd);
980 out_put_path:
981 dput(path.dentry);
982 mntput(path.mnt);
983 goto out_nattch;
986 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
988 unsigned long ret;
989 long err;
991 err = do_shmat(shmid, shmaddr, shmflg, &ret);
992 if (err)
993 return err;
994 force_successful_syscall_return();
995 return (long)ret;
999 * detach and kill segment if marked destroyed.
1000 * The work is done in shm_close.
1002 asmlinkage long sys_shmdt(char __user *shmaddr)
1004 struct mm_struct *mm = current->mm;
1005 struct vm_area_struct *vma, *next;
1006 unsigned long addr = (unsigned long)shmaddr;
1007 loff_t size = 0;
1008 int retval = -EINVAL;
1010 if (addr & ~PAGE_MASK)
1011 return retval;
1013 down_write(&mm->mmap_sem);
1016 * This function tries to be smart and unmap shm segments that
1017 * were modified by partial mlock or munmap calls:
1018 * - It first determines the size of the shm segment that should be
1019 * unmapped: It searches for a vma that is backed by shm and that
1020 * started at address shmaddr. It records it's size and then unmaps
1021 * it.
1022 * - Then it unmaps all shm vmas that started at shmaddr and that
1023 * are within the initially determined size.
1024 * Errors from do_munmap are ignored: the function only fails if
1025 * it's called with invalid parameters or if it's called to unmap
1026 * a part of a vma. Both calls in this function are for full vmas,
1027 * the parameters are directly copied from the vma itself and always
1028 * valid - therefore do_munmap cannot fail. (famous last words?)
1031 * If it had been mremap()'d, the starting address would not
1032 * match the usual checks anyway. So assume all vma's are
1033 * above the starting address given.
1035 vma = find_vma(mm, addr);
1037 while (vma) {
1038 next = vma->vm_next;
1041 * Check if the starting address would match, i.e. it's
1042 * a fragment created by mprotect() and/or munmap(), or it
1043 * otherwise it starts at this address with no hassles.
1045 if ((vma->vm_ops == &shm_vm_ops) &&
1046 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1049 size = vma->vm_file->f_path.dentry->d_inode->i_size;
1050 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1052 * We discovered the size of the shm segment, so
1053 * break out of here and fall through to the next
1054 * loop that uses the size information to stop
1055 * searching for matching vma's.
1057 retval = 0;
1058 vma = next;
1059 break;
1061 vma = next;
1065 * We need look no further than the maximum address a fragment
1066 * could possibly have landed at. Also cast things to loff_t to
1067 * prevent overflows and make comparisions vs. equal-width types.
1069 size = PAGE_ALIGN(size);
1070 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1071 next = vma->vm_next;
1073 /* finding a matching vma now does not alter retval */
1074 if ((vma->vm_ops == &shm_vm_ops) &&
1075 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1077 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1078 vma = next;
1081 up_write(&mm->mmap_sem);
1082 return retval;
1085 #ifdef CONFIG_PROC_FS
1086 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1088 struct shmid_kernel *shp = it;
1089 char *format;
1091 #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1092 #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1094 if (sizeof(size_t) <= sizeof(int))
1095 format = SMALL_STRING;
1096 else
1097 format = BIG_STRING;
1098 return seq_printf(s, format,
1099 shp->shm_perm.key,
1100 shp->id,
1101 shp->shm_perm.mode,
1102 shp->shm_segsz,
1103 shp->shm_cprid,
1104 shp->shm_lprid,
1105 shp->shm_nattch,
1106 shp->shm_perm.uid,
1107 shp->shm_perm.gid,
1108 shp->shm_perm.cuid,
1109 shp->shm_perm.cgid,
1110 shp->shm_atim,
1111 shp->shm_dtim,
1112 shp->shm_ctim);
1114 #endif