Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
[linux-2.6.git] / ipc / shm.c
blobc6b4ad5ce3b7b53df40b5934bb823fff4de9f9c8
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/rwsem.h>
39 #include <linux/nsproxy.h>
40 #include <linux/mount.h>
41 #include <linux/ipc_namespace.h>
43 #include <asm/uaccess.h>
45 #include "util.h"
47 struct shm_file_data {
48 int id;
49 struct ipc_namespace *ns;
50 struct file *file;
51 const struct vm_operations_struct *vm_ops;
54 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
56 static const struct file_operations shm_file_operations;
57 static const struct vm_operations_struct shm_vm_ops;
59 #define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
61 #define shm_unlock(shp) \
62 ipc_unlock(&(shp)->shm_perm)
64 static int newseg(struct ipc_namespace *, struct ipc_params *);
65 static void shm_open(struct vm_area_struct *vma);
66 static void shm_close(struct vm_area_struct *vma);
67 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
68 #ifdef CONFIG_PROC_FS
69 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
70 #endif
72 void shm_init_ns(struct ipc_namespace *ns)
74 ns->shm_ctlmax = SHMMAX;
75 ns->shm_ctlall = SHMALL;
76 ns->shm_ctlmni = SHMMNI;
77 ns->shm_rmid_forced = 0;
78 ns->shm_tot = 0;
79 ipc_init_ids(&shm_ids(ns));
83 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
84 * Only shm_ids.rw_mutex remains locked on exit.
86 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
88 struct shmid_kernel *shp;
89 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
91 if (shp->shm_nattch){
92 shp->shm_perm.mode |= SHM_DEST;
93 /* Do not find it any more */
94 shp->shm_perm.key = IPC_PRIVATE;
95 shm_unlock(shp);
96 } else
97 shm_destroy(ns, shp);
100 #ifdef CONFIG_IPC_NS
101 void shm_exit_ns(struct ipc_namespace *ns)
103 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
104 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
106 #endif
108 static int __init ipc_ns_init(void)
110 shm_init_ns(&init_ipc_ns);
111 return 0;
114 pure_initcall(ipc_ns_init);
116 void __init shm_init (void)
118 ipc_init_proc_interface("sysvipc/shm",
119 #if BITS_PER_LONG <= 32
120 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
121 #else
122 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
123 #endif
124 IPC_SHM_IDS, sysvipc_shm_proc_show);
128 * shm_lock_(check_) routines are called in the paths where the rw_mutex
129 * is not necessarily held.
131 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
133 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
135 if (IS_ERR(ipcp))
136 return (struct shmid_kernel *)ipcp;
138 return container_of(ipcp, struct shmid_kernel, shm_perm);
141 static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
143 rcu_read_lock();
144 ipc_lock_object(&ipcp->shm_perm);
147 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
148 int id)
150 struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
152 if (IS_ERR(ipcp))
153 return (struct shmid_kernel *)ipcp;
155 return container_of(ipcp, struct shmid_kernel, shm_perm);
158 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
160 ipc_rmid(&shm_ids(ns), &s->shm_perm);
164 /* This is called by fork, once for every shm attach. */
165 static void shm_open(struct vm_area_struct *vma)
167 struct file *file = vma->vm_file;
168 struct shm_file_data *sfd = shm_file_data(file);
169 struct shmid_kernel *shp;
171 shp = shm_lock(sfd->ns, sfd->id);
172 BUG_ON(IS_ERR(shp));
173 shp->shm_atim = get_seconds();
174 shp->shm_lprid = task_tgid_vnr(current);
175 shp->shm_nattch++;
176 shm_unlock(shp);
180 * shm_destroy - free the struct shmid_kernel
182 * @ns: namespace
183 * @shp: struct to free
185 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
186 * but returns with shp unlocked and freed.
188 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
190 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
191 shm_rmid(ns, shp);
192 shm_unlock(shp);
193 if (!is_file_hugepages(shp->shm_file))
194 shmem_lock(shp->shm_file, 0, shp->mlock_user);
195 else if (shp->mlock_user)
196 user_shm_unlock(file_inode(shp->shm_file)->i_size,
197 shp->mlock_user);
198 fput (shp->shm_file);
199 security_shm_free(shp);
200 ipc_rcu_putref(shp);
204 * shm_may_destroy - identifies whether shm segment should be destroyed now
206 * Returns true if and only if there are no active users of the segment and
207 * one of the following is true:
209 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
211 * 2) sysctl kernel.shm_rmid_forced is set to 1.
213 static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
215 return (shp->shm_nattch == 0) &&
216 (ns->shm_rmid_forced ||
217 (shp->shm_perm.mode & SHM_DEST));
221 * remove the attach descriptor vma.
222 * free memory for segment if it is marked destroyed.
223 * The descriptor has already been removed from the current->mm->mmap list
224 * and will later be kfree()d.
226 static void shm_close(struct vm_area_struct *vma)
228 struct file * file = vma->vm_file;
229 struct shm_file_data *sfd = shm_file_data(file);
230 struct shmid_kernel *shp;
231 struct ipc_namespace *ns = sfd->ns;
233 down_write(&shm_ids(ns).rw_mutex);
234 /* remove from the list of attaches of the shm segment */
235 shp = shm_lock(ns, sfd->id);
236 BUG_ON(IS_ERR(shp));
237 shp->shm_lprid = task_tgid_vnr(current);
238 shp->shm_dtim = get_seconds();
239 shp->shm_nattch--;
240 if (shm_may_destroy(ns, shp))
241 shm_destroy(ns, shp);
242 else
243 shm_unlock(shp);
244 up_write(&shm_ids(ns).rw_mutex);
247 /* Called with ns->shm_ids(ns).rw_mutex locked */
248 static int shm_try_destroy_current(int id, void *p, void *data)
250 struct ipc_namespace *ns = data;
251 struct kern_ipc_perm *ipcp = p;
252 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
254 if (shp->shm_creator != current)
255 return 0;
258 * Mark it as orphaned to destroy the segment when
259 * kernel.shm_rmid_forced is changed.
260 * It is noop if the following shm_may_destroy() returns true.
262 shp->shm_creator = NULL;
265 * Don't even try to destroy it. If shm_rmid_forced=0 and IPC_RMID
266 * is not set, it shouldn't be deleted here.
268 if (!ns->shm_rmid_forced)
269 return 0;
271 if (shm_may_destroy(ns, shp)) {
272 shm_lock_by_ptr(shp);
273 shm_destroy(ns, shp);
275 return 0;
278 /* Called with ns->shm_ids(ns).rw_mutex locked */
279 static int shm_try_destroy_orphaned(int id, void *p, void *data)
281 struct ipc_namespace *ns = data;
282 struct kern_ipc_perm *ipcp = p;
283 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
286 * We want to destroy segments without users and with already
287 * exit'ed originating process.
289 * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
291 if (shp->shm_creator != NULL)
292 return 0;
294 if (shm_may_destroy(ns, shp)) {
295 shm_lock_by_ptr(shp);
296 shm_destroy(ns, shp);
298 return 0;
301 void shm_destroy_orphaned(struct ipc_namespace *ns)
303 down_write(&shm_ids(ns).rw_mutex);
304 if (shm_ids(ns).in_use)
305 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
306 up_write(&shm_ids(ns).rw_mutex);
310 void exit_shm(struct task_struct *task)
312 struct ipc_namespace *ns = task->nsproxy->ipc_ns;
314 if (shm_ids(ns).in_use == 0)
315 return;
317 /* Destroy all already created segments, but not mapped yet */
318 down_write(&shm_ids(ns).rw_mutex);
319 if (shm_ids(ns).in_use)
320 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
321 up_write(&shm_ids(ns).rw_mutex);
324 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
326 struct file *file = vma->vm_file;
327 struct shm_file_data *sfd = shm_file_data(file);
329 return sfd->vm_ops->fault(vma, vmf);
332 #ifdef CONFIG_NUMA
333 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
335 struct file *file = vma->vm_file;
336 struct shm_file_data *sfd = shm_file_data(file);
337 int err = 0;
338 if (sfd->vm_ops->set_policy)
339 err = sfd->vm_ops->set_policy(vma, new);
340 return err;
343 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
344 unsigned long addr)
346 struct file *file = vma->vm_file;
347 struct shm_file_data *sfd = shm_file_data(file);
348 struct mempolicy *pol = NULL;
350 if (sfd->vm_ops->get_policy)
351 pol = sfd->vm_ops->get_policy(vma, addr);
352 else if (vma->vm_policy)
353 pol = vma->vm_policy;
355 return pol;
357 #endif
359 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
361 struct shm_file_data *sfd = shm_file_data(file);
362 int ret;
364 ret = sfd->file->f_op->mmap(sfd->file, vma);
365 if (ret != 0)
366 return ret;
367 sfd->vm_ops = vma->vm_ops;
368 #ifdef CONFIG_MMU
369 BUG_ON(!sfd->vm_ops->fault);
370 #endif
371 vma->vm_ops = &shm_vm_ops;
372 shm_open(vma);
374 return ret;
377 static int shm_release(struct inode *ino, struct file *file)
379 struct shm_file_data *sfd = shm_file_data(file);
381 put_ipc_ns(sfd->ns);
382 shm_file_data(file) = NULL;
383 kfree(sfd);
384 return 0;
387 static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
389 struct shm_file_data *sfd = shm_file_data(file);
391 if (!sfd->file->f_op->fsync)
392 return -EINVAL;
393 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
396 static long shm_fallocate(struct file *file, int mode, loff_t offset,
397 loff_t len)
399 struct shm_file_data *sfd = shm_file_data(file);
401 if (!sfd->file->f_op->fallocate)
402 return -EOPNOTSUPP;
403 return sfd->file->f_op->fallocate(file, mode, offset, len);
406 static unsigned long shm_get_unmapped_area(struct file *file,
407 unsigned long addr, unsigned long len, unsigned long pgoff,
408 unsigned long flags)
410 struct shm_file_data *sfd = shm_file_data(file);
411 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
412 pgoff, flags);
415 static const struct file_operations shm_file_operations = {
416 .mmap = shm_mmap,
417 .fsync = shm_fsync,
418 .release = shm_release,
419 #ifndef CONFIG_MMU
420 .get_unmapped_area = shm_get_unmapped_area,
421 #endif
422 .llseek = noop_llseek,
423 .fallocate = shm_fallocate,
426 static const struct file_operations shm_file_operations_huge = {
427 .mmap = shm_mmap,
428 .fsync = shm_fsync,
429 .release = shm_release,
430 .get_unmapped_area = shm_get_unmapped_area,
431 .llseek = noop_llseek,
432 .fallocate = shm_fallocate,
435 int is_file_shm_hugepages(struct file *file)
437 return file->f_op == &shm_file_operations_huge;
440 static const struct vm_operations_struct shm_vm_ops = {
441 .open = shm_open, /* callback for a new vm-area open */
442 .close = shm_close, /* callback for when the vm-area is released */
443 .fault = shm_fault,
444 #if defined(CONFIG_NUMA)
445 .set_policy = shm_set_policy,
446 .get_policy = shm_get_policy,
447 #endif
451 * newseg - Create a new shared memory segment
452 * @ns: namespace
453 * @params: ptr to the structure that contains key, size and shmflg
455 * Called with shm_ids.rw_mutex held as a writer.
458 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
460 key_t key = params->key;
461 int shmflg = params->flg;
462 size_t size = params->u.size;
463 int error;
464 struct shmid_kernel *shp;
465 size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
466 struct file * file;
467 char name[13];
468 int id;
469 vm_flags_t acctflag = 0;
471 if (size < SHMMIN || size > ns->shm_ctlmax)
472 return -EINVAL;
474 if (ns->shm_tot + numpages > ns->shm_ctlall)
475 return -ENOSPC;
477 shp = ipc_rcu_alloc(sizeof(*shp));
478 if (!shp)
479 return -ENOMEM;
481 shp->shm_perm.key = key;
482 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
483 shp->mlock_user = NULL;
485 shp->shm_perm.security = NULL;
486 error = security_shm_alloc(shp);
487 if (error) {
488 ipc_rcu_putref(shp);
489 return error;
492 sprintf (name, "SYSV%08x", key);
493 if (shmflg & SHM_HUGETLB) {
494 struct hstate *hs;
495 size_t hugesize;
497 hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
498 if (!hs) {
499 error = -EINVAL;
500 goto no_file;
502 hugesize = ALIGN(size, huge_page_size(hs));
504 /* hugetlb_file_setup applies strict accounting */
505 if (shmflg & SHM_NORESERVE)
506 acctflag = VM_NORESERVE;
507 file = hugetlb_file_setup(name, hugesize, acctflag,
508 &shp->mlock_user, HUGETLB_SHMFS_INODE,
509 (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
510 } else {
512 * Do not allow no accounting for OVERCOMMIT_NEVER, even
513 * if it's asked for.
515 if ((shmflg & SHM_NORESERVE) &&
516 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
517 acctflag = VM_NORESERVE;
518 file = shmem_file_setup(name, size, acctflag);
520 error = PTR_ERR(file);
521 if (IS_ERR(file))
522 goto no_file;
524 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
525 if (id < 0) {
526 error = id;
527 goto no_id;
530 shp->shm_cprid = task_tgid_vnr(current);
531 shp->shm_lprid = 0;
532 shp->shm_atim = shp->shm_dtim = 0;
533 shp->shm_ctim = get_seconds();
534 shp->shm_segsz = size;
535 shp->shm_nattch = 0;
536 shp->shm_file = file;
537 shp->shm_creator = current;
540 * shmid gets reported as "inode#" in /proc/pid/maps.
541 * proc-ps tools use this. Changing this will break them.
543 file_inode(file)->i_ino = shp->shm_perm.id;
545 ns->shm_tot += numpages;
546 error = shp->shm_perm.id;
548 ipc_unlock_object(&shp->shm_perm);
549 rcu_read_unlock();
550 return error;
552 no_id:
553 if (is_file_hugepages(file) && shp->mlock_user)
554 user_shm_unlock(size, shp->mlock_user);
555 fput(file);
556 no_file:
557 security_shm_free(shp);
558 ipc_rcu_putref(shp);
559 return error;
563 * Called with shm_ids.rw_mutex and ipcp locked.
565 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
567 struct shmid_kernel *shp;
569 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
570 return security_shm_associate(shp, shmflg);
574 * Called with shm_ids.rw_mutex and ipcp locked.
576 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
577 struct ipc_params *params)
579 struct shmid_kernel *shp;
581 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
582 if (shp->shm_segsz < params->u.size)
583 return -EINVAL;
585 return 0;
588 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
590 struct ipc_namespace *ns;
591 struct ipc_ops shm_ops;
592 struct ipc_params shm_params;
594 ns = current->nsproxy->ipc_ns;
596 shm_ops.getnew = newseg;
597 shm_ops.associate = shm_security;
598 shm_ops.more_checks = shm_more_checks;
600 shm_params.key = key;
601 shm_params.flg = shmflg;
602 shm_params.u.size = size;
604 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
607 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
609 switch(version) {
610 case IPC_64:
611 return copy_to_user(buf, in, sizeof(*in));
612 case IPC_OLD:
614 struct shmid_ds out;
616 memset(&out, 0, sizeof(out));
617 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
618 out.shm_segsz = in->shm_segsz;
619 out.shm_atime = in->shm_atime;
620 out.shm_dtime = in->shm_dtime;
621 out.shm_ctime = in->shm_ctime;
622 out.shm_cpid = in->shm_cpid;
623 out.shm_lpid = in->shm_lpid;
624 out.shm_nattch = in->shm_nattch;
626 return copy_to_user(buf, &out, sizeof(out));
628 default:
629 return -EINVAL;
633 static inline unsigned long
634 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
636 switch(version) {
637 case IPC_64:
638 if (copy_from_user(out, buf, sizeof(*out)))
639 return -EFAULT;
640 return 0;
641 case IPC_OLD:
643 struct shmid_ds tbuf_old;
645 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
646 return -EFAULT;
648 out->shm_perm.uid = tbuf_old.shm_perm.uid;
649 out->shm_perm.gid = tbuf_old.shm_perm.gid;
650 out->shm_perm.mode = tbuf_old.shm_perm.mode;
652 return 0;
654 default:
655 return -EINVAL;
659 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
661 switch(version) {
662 case IPC_64:
663 return copy_to_user(buf, in, sizeof(*in));
664 case IPC_OLD:
666 struct shminfo out;
668 if(in->shmmax > INT_MAX)
669 out.shmmax = INT_MAX;
670 else
671 out.shmmax = (int)in->shmmax;
673 out.shmmin = in->shmmin;
674 out.shmmni = in->shmmni;
675 out.shmseg = in->shmseg;
676 out.shmall = in->shmall;
678 return copy_to_user(buf, &out, sizeof(out));
680 default:
681 return -EINVAL;
686 * Calculate and add used RSS and swap pages of a shm.
687 * Called with shm_ids.rw_mutex held as a reader
689 static void shm_add_rss_swap(struct shmid_kernel *shp,
690 unsigned long *rss_add, unsigned long *swp_add)
692 struct inode *inode;
694 inode = file_inode(shp->shm_file);
696 if (is_file_hugepages(shp->shm_file)) {
697 struct address_space *mapping = inode->i_mapping;
698 struct hstate *h = hstate_file(shp->shm_file);
699 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
700 } else {
701 #ifdef CONFIG_SHMEM
702 struct shmem_inode_info *info = SHMEM_I(inode);
703 spin_lock(&info->lock);
704 *rss_add += inode->i_mapping->nrpages;
705 *swp_add += info->swapped;
706 spin_unlock(&info->lock);
707 #else
708 *rss_add += inode->i_mapping->nrpages;
709 #endif
714 * Called with shm_ids.rw_mutex held as a reader
716 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
717 unsigned long *swp)
719 int next_id;
720 int total, in_use;
722 *rss = 0;
723 *swp = 0;
725 in_use = shm_ids(ns).in_use;
727 for (total = 0, next_id = 0; total < in_use; next_id++) {
728 struct kern_ipc_perm *ipc;
729 struct shmid_kernel *shp;
731 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
732 if (ipc == NULL)
733 continue;
734 shp = container_of(ipc, struct shmid_kernel, shm_perm);
736 shm_add_rss_swap(shp, rss, swp);
738 total++;
743 * This function handles some shmctl commands which require the rw_mutex
744 * to be held in write mode.
745 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
747 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
748 struct shmid_ds __user *buf, int version)
750 struct kern_ipc_perm *ipcp;
751 struct shmid64_ds shmid64;
752 struct shmid_kernel *shp;
753 int err;
755 if (cmd == IPC_SET) {
756 if (copy_shmid_from_user(&shmid64, buf, version))
757 return -EFAULT;
760 down_write(&shm_ids(ns).rw_mutex);
761 rcu_read_lock();
763 ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
764 &shmid64.shm_perm, 0);
765 if (IS_ERR(ipcp)) {
766 err = PTR_ERR(ipcp);
767 /* the ipc lock is not held upon failure */
768 goto out_unlock1;
771 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
773 err = security_shm_shmctl(shp, cmd);
774 if (err)
775 goto out_unlock0;
777 switch (cmd) {
778 case IPC_RMID:
779 /* do_shm_rmid unlocks the ipc object and rcu */
780 do_shm_rmid(ns, ipcp);
781 goto out_up;
782 case IPC_SET:
783 err = ipc_update_perm(&shmid64.shm_perm, ipcp);
784 if (err)
785 goto out_unlock0;
786 shp->shm_ctim = get_seconds();
787 break;
788 default:
789 err = -EINVAL;
792 out_unlock0:
793 ipc_unlock_object(&shp->shm_perm);
794 out_unlock1:
795 rcu_read_unlock();
796 out_up:
797 up_write(&shm_ids(ns).rw_mutex);
798 return err;
801 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
803 struct shmid_kernel *shp;
804 int err, version;
805 struct ipc_namespace *ns;
807 if (cmd < 0 || shmid < 0) {
808 err = -EINVAL;
809 goto out;
812 version = ipc_parse_version(&cmd);
813 ns = current->nsproxy->ipc_ns;
815 switch (cmd) { /* replace with proc interface ? */
816 case IPC_INFO:
818 struct shminfo64 shminfo;
820 err = security_shm_shmctl(NULL, cmd);
821 if (err)
822 return err;
824 memset(&shminfo, 0, sizeof(shminfo));
825 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
826 shminfo.shmmax = ns->shm_ctlmax;
827 shminfo.shmall = ns->shm_ctlall;
829 shminfo.shmmin = SHMMIN;
830 if(copy_shminfo_to_user (buf, &shminfo, version))
831 return -EFAULT;
833 down_read(&shm_ids(ns).rw_mutex);
834 err = ipc_get_maxid(&shm_ids(ns));
835 up_read(&shm_ids(ns).rw_mutex);
837 if(err<0)
838 err = 0;
839 goto out;
841 case SHM_INFO:
843 struct shm_info shm_info;
845 err = security_shm_shmctl(NULL, cmd);
846 if (err)
847 return err;
849 memset(&shm_info, 0, sizeof(shm_info));
850 down_read(&shm_ids(ns).rw_mutex);
851 shm_info.used_ids = shm_ids(ns).in_use;
852 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
853 shm_info.shm_tot = ns->shm_tot;
854 shm_info.swap_attempts = 0;
855 shm_info.swap_successes = 0;
856 err = ipc_get_maxid(&shm_ids(ns));
857 up_read(&shm_ids(ns).rw_mutex);
858 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
859 err = -EFAULT;
860 goto out;
863 err = err < 0 ? 0 : err;
864 goto out;
866 case SHM_STAT:
867 case IPC_STAT:
869 struct shmid64_ds tbuf;
870 int result;
872 if (cmd == SHM_STAT) {
873 shp = shm_lock(ns, shmid);
874 if (IS_ERR(shp)) {
875 err = PTR_ERR(shp);
876 goto out;
878 result = shp->shm_perm.id;
879 } else {
880 shp = shm_lock_check(ns, shmid);
881 if (IS_ERR(shp)) {
882 err = PTR_ERR(shp);
883 goto out;
885 result = 0;
887 err = -EACCES;
888 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
889 goto out_unlock;
890 err = security_shm_shmctl(shp, cmd);
891 if (err)
892 goto out_unlock;
893 memset(&tbuf, 0, sizeof(tbuf));
894 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
895 tbuf.shm_segsz = shp->shm_segsz;
896 tbuf.shm_atime = shp->shm_atim;
897 tbuf.shm_dtime = shp->shm_dtim;
898 tbuf.shm_ctime = shp->shm_ctim;
899 tbuf.shm_cpid = shp->shm_cprid;
900 tbuf.shm_lpid = shp->shm_lprid;
901 tbuf.shm_nattch = shp->shm_nattch;
902 shm_unlock(shp);
903 if(copy_shmid_to_user (buf, &tbuf, version))
904 err = -EFAULT;
905 else
906 err = result;
907 goto out;
909 case SHM_LOCK:
910 case SHM_UNLOCK:
912 struct file *shm_file;
914 shp = shm_lock_check(ns, shmid);
915 if (IS_ERR(shp)) {
916 err = PTR_ERR(shp);
917 goto out;
920 audit_ipc_obj(&(shp->shm_perm));
922 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
923 kuid_t euid = current_euid();
924 err = -EPERM;
925 if (!uid_eq(euid, shp->shm_perm.uid) &&
926 !uid_eq(euid, shp->shm_perm.cuid))
927 goto out_unlock;
928 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
929 goto out_unlock;
932 err = security_shm_shmctl(shp, cmd);
933 if (err)
934 goto out_unlock;
936 shm_file = shp->shm_file;
937 if (is_file_hugepages(shm_file))
938 goto out_unlock;
940 if (cmd == SHM_LOCK) {
941 struct user_struct *user = current_user();
942 err = shmem_lock(shm_file, 1, user);
943 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
944 shp->shm_perm.mode |= SHM_LOCKED;
945 shp->mlock_user = user;
947 goto out_unlock;
950 /* SHM_UNLOCK */
951 if (!(shp->shm_perm.mode & SHM_LOCKED))
952 goto out_unlock;
953 shmem_lock(shm_file, 0, shp->mlock_user);
954 shp->shm_perm.mode &= ~SHM_LOCKED;
955 shp->mlock_user = NULL;
956 get_file(shm_file);
957 shm_unlock(shp);
958 shmem_unlock_mapping(shm_file->f_mapping);
959 fput(shm_file);
960 goto out;
962 case IPC_RMID:
963 case IPC_SET:
964 err = shmctl_down(ns, shmid, cmd, buf, version);
965 return err;
966 default:
967 return -EINVAL;
970 out_unlock:
971 shm_unlock(shp);
972 out:
973 return err;
977 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
979 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
980 * "raddr" thing points to kernel space, and there has to be a wrapper around
981 * this.
983 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
984 unsigned long shmlba)
986 struct shmid_kernel *shp;
987 unsigned long addr;
988 unsigned long size;
989 struct file * file;
990 int err;
991 unsigned long flags;
992 unsigned long prot;
993 int acc_mode;
994 struct ipc_namespace *ns;
995 struct shm_file_data *sfd;
996 struct path path;
997 fmode_t f_mode;
998 unsigned long populate = 0;
1000 err = -EINVAL;
1001 if (shmid < 0)
1002 goto out;
1003 else if ((addr = (ulong)shmaddr)) {
1004 if (addr & (shmlba - 1)) {
1005 if (shmflg & SHM_RND)
1006 addr &= ~(shmlba - 1); /* round down */
1007 else
1008 #ifndef __ARCH_FORCE_SHMLBA
1009 if (addr & ~PAGE_MASK)
1010 #endif
1011 goto out;
1013 flags = MAP_SHARED | MAP_FIXED;
1014 } else {
1015 if ((shmflg & SHM_REMAP))
1016 goto out;
1018 flags = MAP_SHARED;
1021 if (shmflg & SHM_RDONLY) {
1022 prot = PROT_READ;
1023 acc_mode = S_IRUGO;
1024 f_mode = FMODE_READ;
1025 } else {
1026 prot = PROT_READ | PROT_WRITE;
1027 acc_mode = S_IRUGO | S_IWUGO;
1028 f_mode = FMODE_READ | FMODE_WRITE;
1030 if (shmflg & SHM_EXEC) {
1031 prot |= PROT_EXEC;
1032 acc_mode |= S_IXUGO;
1036 * We cannot rely on the fs check since SYSV IPC does have an
1037 * additional creator id...
1039 ns = current->nsproxy->ipc_ns;
1040 shp = shm_lock_check(ns, shmid);
1041 if (IS_ERR(shp)) {
1042 err = PTR_ERR(shp);
1043 goto out;
1046 err = -EACCES;
1047 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1048 goto out_unlock;
1050 err = security_shm_shmat(shp, shmaddr, shmflg);
1051 if (err)
1052 goto out_unlock;
1054 path = shp->shm_file->f_path;
1055 path_get(&path);
1056 shp->shm_nattch++;
1057 size = i_size_read(path.dentry->d_inode);
1058 shm_unlock(shp);
1060 err = -ENOMEM;
1061 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1062 if (!sfd)
1063 goto out_put_dentry;
1065 file = alloc_file(&path, f_mode,
1066 is_file_hugepages(shp->shm_file) ?
1067 &shm_file_operations_huge :
1068 &shm_file_operations);
1069 err = PTR_ERR(file);
1070 if (IS_ERR(file))
1071 goto out_free;
1073 file->private_data = sfd;
1074 file->f_mapping = shp->shm_file->f_mapping;
1075 sfd->id = shp->shm_perm.id;
1076 sfd->ns = get_ipc_ns(ns);
1077 sfd->file = shp->shm_file;
1078 sfd->vm_ops = NULL;
1080 err = security_mmap_file(file, prot, flags);
1081 if (err)
1082 goto out_fput;
1084 down_write(&current->mm->mmap_sem);
1085 if (addr && !(shmflg & SHM_REMAP)) {
1086 err = -EINVAL;
1087 if (find_vma_intersection(current->mm, addr, addr + size))
1088 goto invalid;
1090 * If shm segment goes below stack, make sure there is some
1091 * space left for the stack to grow (at least 4 pages).
1093 if (addr < current->mm->start_stack &&
1094 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1095 goto invalid;
1098 addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate);
1099 *raddr = addr;
1100 err = 0;
1101 if (IS_ERR_VALUE(addr))
1102 err = (long)addr;
1103 invalid:
1104 up_write(&current->mm->mmap_sem);
1105 if (populate)
1106 mm_populate(addr, populate);
1108 out_fput:
1109 fput(file);
1111 out_nattch:
1112 down_write(&shm_ids(ns).rw_mutex);
1113 shp = shm_lock(ns, shmid);
1114 BUG_ON(IS_ERR(shp));
1115 shp->shm_nattch--;
1116 if (shm_may_destroy(ns, shp))
1117 shm_destroy(ns, shp);
1118 else
1119 shm_unlock(shp);
1120 up_write(&shm_ids(ns).rw_mutex);
1122 out:
1123 return err;
1125 out_unlock:
1126 shm_unlock(shp);
1127 goto out;
1129 out_free:
1130 kfree(sfd);
1131 out_put_dentry:
1132 path_put(&path);
1133 goto out_nattch;
1136 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1138 unsigned long ret;
1139 long err;
1141 err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1142 if (err)
1143 return err;
1144 force_successful_syscall_return();
1145 return (long)ret;
1149 * detach and kill segment if marked destroyed.
1150 * The work is done in shm_close.
1152 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1154 struct mm_struct *mm = current->mm;
1155 struct vm_area_struct *vma;
1156 unsigned long addr = (unsigned long)shmaddr;
1157 int retval = -EINVAL;
1158 #ifdef CONFIG_MMU
1159 loff_t size = 0;
1160 struct vm_area_struct *next;
1161 #endif
1163 if (addr & ~PAGE_MASK)
1164 return retval;
1166 down_write(&mm->mmap_sem);
1169 * This function tries to be smart and unmap shm segments that
1170 * were modified by partial mlock or munmap calls:
1171 * - It first determines the size of the shm segment that should be
1172 * unmapped: It searches for a vma that is backed by shm and that
1173 * started at address shmaddr. It records it's size and then unmaps
1174 * it.
1175 * - Then it unmaps all shm vmas that started at shmaddr and that
1176 * are within the initially determined size.
1177 * Errors from do_munmap are ignored: the function only fails if
1178 * it's called with invalid parameters or if it's called to unmap
1179 * a part of a vma. Both calls in this function are for full vmas,
1180 * the parameters are directly copied from the vma itself and always
1181 * valid - therefore do_munmap cannot fail. (famous last words?)
1184 * If it had been mremap()'d, the starting address would not
1185 * match the usual checks anyway. So assume all vma's are
1186 * above the starting address given.
1188 vma = find_vma(mm, addr);
1190 #ifdef CONFIG_MMU
1191 while (vma) {
1192 next = vma->vm_next;
1195 * Check if the starting address would match, i.e. it's
1196 * a fragment created by mprotect() and/or munmap(), or it
1197 * otherwise it starts at this address with no hassles.
1199 if ((vma->vm_ops == &shm_vm_ops) &&
1200 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1203 size = file_inode(vma->vm_file)->i_size;
1204 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1206 * We discovered the size of the shm segment, so
1207 * break out of here and fall through to the next
1208 * loop that uses the size information to stop
1209 * searching for matching vma's.
1211 retval = 0;
1212 vma = next;
1213 break;
1215 vma = next;
1219 * We need look no further than the maximum address a fragment
1220 * could possibly have landed at. Also cast things to loff_t to
1221 * prevent overflows and make comparisons vs. equal-width types.
1223 size = PAGE_ALIGN(size);
1224 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1225 next = vma->vm_next;
1227 /* finding a matching vma now does not alter retval */
1228 if ((vma->vm_ops == &shm_vm_ops) &&
1229 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1231 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1232 vma = next;
1235 #else /* CONFIG_MMU */
1236 /* under NOMMU conditions, the exact address to be destroyed must be
1237 * given */
1238 retval = -EINVAL;
1239 if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1240 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1241 retval = 0;
1244 #endif
1246 up_write(&mm->mmap_sem);
1247 return retval;
1250 #ifdef CONFIG_PROC_FS
1251 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1253 struct user_namespace *user_ns = seq_user_ns(s);
1254 struct shmid_kernel *shp = it;
1255 unsigned long rss = 0, swp = 0;
1257 shm_add_rss_swap(shp, &rss, &swp);
1259 #if BITS_PER_LONG <= 32
1260 #define SIZE_SPEC "%10lu"
1261 #else
1262 #define SIZE_SPEC "%21lu"
1263 #endif
1265 return seq_printf(s,
1266 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1267 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1268 SIZE_SPEC " " SIZE_SPEC "\n",
1269 shp->shm_perm.key,
1270 shp->shm_perm.id,
1271 shp->shm_perm.mode,
1272 shp->shm_segsz,
1273 shp->shm_cprid,
1274 shp->shm_lprid,
1275 shp->shm_nattch,
1276 from_kuid_munged(user_ns, shp->shm_perm.uid),
1277 from_kgid_munged(user_ns, shp->shm_perm.gid),
1278 from_kuid_munged(user_ns, shp->shm_perm.cuid),
1279 from_kgid_munged(user_ns, shp->shm_perm.cgid),
1280 shp->shm_atim,
1281 shp->shm_dtim,
1282 shp->shm_ctim,
1283 rss * PAGE_SIZE,
1284 swp * PAGE_SIZE);
1286 #endif