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>
21 * Pavel Emelianov <xemul@openvz.org>
24 #include <linux/slab.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>
46 struct shm_file_data
{
48 struct ipc_namespace
*ns
;
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_unlock(shp) \
63 ipc_unlock(&(shp)->shm_perm)
64 #define shm_buildid(ns, id, seq) \
65 ipc_buildid(&shm_ids(ns), id, seq)
67 static int newseg(struct ipc_namespace
*, struct ipc_params
*);
68 static void shm_open(struct vm_area_struct
*vma
);
69 static void shm_close(struct vm_area_struct
*vma
);
70 static void shm_destroy (struct ipc_namespace
*ns
, struct shmid_kernel
*shp
);
72 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
);
75 static void __shm_init_ns(struct ipc_namespace
*ns
, struct ipc_ids
*ids
)
77 ns
->ids
[IPC_SHM_IDS
] = ids
;
78 ns
->shm_ctlmax
= SHMMAX
;
79 ns
->shm_ctlall
= SHMALL
;
80 ns
->shm_ctlmni
= SHMMNI
;
85 static void do_shm_rmid(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
88 shp
->shm_perm
.mode
|= SHM_DEST
;
89 /* Do not find it any more */
90 shp
->shm_perm
.key
= IPC_PRIVATE
;
96 int shm_init_ns(struct ipc_namespace
*ns
)
100 ids
= kmalloc(sizeof(struct ipc_ids
), GFP_KERNEL
);
104 __shm_init_ns(ns
, ids
);
108 void shm_exit_ns(struct ipc_namespace
*ns
)
110 struct shmid_kernel
*shp
;
114 mutex_lock(&shm_ids(ns
).mutex
);
116 in_use
= shm_ids(ns
).in_use
;
118 for (total
= 0, next_id
= 0; total
< in_use
; next_id
++) {
119 shp
= idr_find(&shm_ids(ns
).ipcs_idr
, next_id
);
122 ipc_lock_by_ptr(&shp
->shm_perm
);
123 do_shm_rmid(ns
, shp
);
126 mutex_unlock(&shm_ids(ns
).mutex
);
128 kfree(ns
->ids
[IPC_SHM_IDS
]);
129 ns
->ids
[IPC_SHM_IDS
] = NULL
;
132 void __init
shm_init (void)
134 __shm_init_ns(&init_ipc_ns
, &init_shm_ids
);
135 ipc_init_proc_interface("sysvipc/shm",
136 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
137 IPC_SHM_IDS
, sysvipc_shm_proc_show
);
140 static inline struct shmid_kernel
*shm_lock(struct ipc_namespace
*ns
, int id
)
142 return (struct shmid_kernel
*) ipc_lock(&shm_ids(ns
), id
);
145 static inline struct shmid_kernel
*shm_lock_check(struct ipc_namespace
*ns
,
148 return (struct shmid_kernel
*) ipc_lock_check(&shm_ids(ns
), id
);
151 static inline void shm_rmid(struct ipc_namespace
*ns
, struct shmid_kernel
*s
)
153 ipc_rmid(&shm_ids(ns
), &s
->shm_perm
);
156 static inline int shm_addid(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
158 return ipc_addid(&shm_ids(ns
), &shp
->shm_perm
, ns
->shm_ctlmni
);
163 /* This is called by fork, once for every shm attach. */
164 static void shm_open(struct vm_area_struct
*vma
)
166 struct file
*file
= vma
->vm_file
;
167 struct shm_file_data
*sfd
= shm_file_data(file
);
168 struct shmid_kernel
*shp
;
170 shp
= shm_lock(sfd
->ns
, sfd
->id
);
172 shp
->shm_atim
= get_seconds();
173 shp
->shm_lprid
= task_tgid_vnr(current
);
179 * shm_destroy - free the struct shmid_kernel
181 * @shp: struct to free
183 * It has to be called with shp and shm_ids.mutex locked,
184 * but returns with shp unlocked and freed.
186 static void shm_destroy(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
188 ns
->shm_tot
-= (shp
->shm_segsz
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
191 if (!is_file_hugepages(shp
->shm_file
))
192 shmem_lock(shp
->shm_file
, 0, shp
->mlock_user
);
194 user_shm_unlock(shp
->shm_file
->f_path
.dentry
->d_inode
->i_size
,
196 fput (shp
->shm_file
);
197 security_shm_free(shp
);
202 * remove the attach descriptor vma.
203 * free memory for segment if it is marked destroyed.
204 * The descriptor has already been removed from the current->mm->mmap list
205 * and will later be kfree()d.
207 static void shm_close(struct vm_area_struct
*vma
)
209 struct file
* file
= vma
->vm_file
;
210 struct shm_file_data
*sfd
= shm_file_data(file
);
211 struct shmid_kernel
*shp
;
212 struct ipc_namespace
*ns
= sfd
->ns
;
214 mutex_lock(&shm_ids(ns
).mutex
);
215 /* remove from the list of attaches of the shm segment */
216 shp
= shm_lock(ns
, sfd
->id
);
218 shp
->shm_lprid
= task_tgid_vnr(current
);
219 shp
->shm_dtim
= get_seconds();
221 if(shp
->shm_nattch
== 0 &&
222 shp
->shm_perm
.mode
& SHM_DEST
)
223 shm_destroy(ns
, shp
);
226 mutex_unlock(&shm_ids(ns
).mutex
);
229 static int shm_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
231 struct file
*file
= vma
->vm_file
;
232 struct shm_file_data
*sfd
= shm_file_data(file
);
234 return sfd
->vm_ops
->fault(vma
, vmf
);
238 static int shm_set_policy(struct vm_area_struct
*vma
, struct mempolicy
*new)
240 struct file
*file
= vma
->vm_file
;
241 struct shm_file_data
*sfd
= shm_file_data(file
);
243 if (sfd
->vm_ops
->set_policy
)
244 err
= sfd
->vm_ops
->set_policy(vma
, new);
248 static struct mempolicy
*shm_get_policy(struct vm_area_struct
*vma
,
251 struct file
*file
= vma
->vm_file
;
252 struct shm_file_data
*sfd
= shm_file_data(file
);
253 struct mempolicy
*pol
= NULL
;
255 if (sfd
->vm_ops
->get_policy
)
256 pol
= sfd
->vm_ops
->get_policy(vma
, addr
);
257 else if (vma
->vm_policy
)
258 pol
= vma
->vm_policy
;
260 pol
= current
->mempolicy
;
265 static int shm_mmap(struct file
* file
, struct vm_area_struct
* vma
)
267 struct shm_file_data
*sfd
= shm_file_data(file
);
270 ret
= sfd
->file
->f_op
->mmap(sfd
->file
, vma
);
273 sfd
->vm_ops
= vma
->vm_ops
;
275 BUG_ON(!sfd
->vm_ops
->fault
);
277 vma
->vm_ops
= &shm_vm_ops
;
283 static int shm_release(struct inode
*ino
, struct file
*file
)
285 struct shm_file_data
*sfd
= shm_file_data(file
);
288 shm_file_data(file
) = NULL
;
293 static int shm_fsync(struct file
*file
, struct dentry
*dentry
, int datasync
)
295 int (*fsync
) (struct file
*, struct dentry
*, int datasync
);
296 struct shm_file_data
*sfd
= shm_file_data(file
);
299 fsync
= sfd
->file
->f_op
->fsync
;
301 ret
= fsync(sfd
->file
, sfd
->file
->f_path
.dentry
, datasync
);
305 static unsigned long shm_get_unmapped_area(struct file
*file
,
306 unsigned long addr
, unsigned long len
, unsigned long pgoff
,
309 struct shm_file_data
*sfd
= shm_file_data(file
);
310 return get_unmapped_area(sfd
->file
, addr
, len
, pgoff
, flags
);
313 int is_file_shm_hugepages(struct file
*file
)
317 if (file
->f_op
== &shm_file_operations
) {
318 struct shm_file_data
*sfd
;
319 sfd
= shm_file_data(file
);
320 ret
= is_file_hugepages(sfd
->file
);
325 static const struct file_operations shm_file_operations
= {
328 .release
= shm_release
,
329 .get_unmapped_area
= shm_get_unmapped_area
,
332 static struct vm_operations_struct shm_vm_ops
= {
333 .open
= shm_open
, /* callback for a new vm-area open */
334 .close
= shm_close
, /* callback for when the vm-area is released */
336 #if defined(CONFIG_NUMA)
337 .set_policy
= shm_set_policy
,
338 .get_policy
= shm_get_policy
,
342 static int newseg(struct ipc_namespace
*ns
, struct ipc_params
*params
)
344 key_t key
= params
->key
;
345 int shmflg
= params
->flg
;
346 size_t size
= params
->u
.size
;
348 struct shmid_kernel
*shp
;
349 int numpages
= (size
+ PAGE_SIZE
-1) >> PAGE_SHIFT
;
354 if (size
< SHMMIN
|| size
> ns
->shm_ctlmax
)
357 if (ns
->shm_tot
+ numpages
> ns
->shm_ctlall
)
360 shp
= ipc_rcu_alloc(sizeof(*shp
));
364 shp
->shm_perm
.key
= key
;
365 shp
->shm_perm
.mode
= (shmflg
& S_IRWXUGO
);
366 shp
->mlock_user
= NULL
;
368 shp
->shm_perm
.security
= NULL
;
369 error
= security_shm_alloc(shp
);
375 sprintf (name
, "SYSV%08x", key
);
376 if (shmflg
& SHM_HUGETLB
) {
377 /* hugetlb_file_setup takes care of mlock user accounting */
378 file
= hugetlb_file_setup(name
, size
);
379 shp
->mlock_user
= current
->user
;
381 int acctflag
= VM_ACCOUNT
;
383 * Do not allow no accounting for OVERCOMMIT_NEVER, even
386 if ((shmflg
& SHM_NORESERVE
) &&
387 sysctl_overcommit_memory
!= OVERCOMMIT_NEVER
)
389 file
= shmem_file_setup(name
, size
, acctflag
);
391 error
= PTR_ERR(file
);
396 id
= shm_addid(ns
, shp
);
400 shp
->shm_cprid
= task_tgid_vnr(current
);
402 shp
->shm_atim
= shp
->shm_dtim
= 0;
403 shp
->shm_ctim
= get_seconds();
404 shp
->shm_segsz
= size
;
406 shp
->shm_perm
.id
= shm_buildid(ns
, id
, shp
->shm_perm
.seq
);
407 shp
->shm_file
= file
;
409 * shmid gets reported as "inode#" in /proc/pid/maps.
410 * proc-ps tools use this. Changing this will break them.
412 file
->f_dentry
->d_inode
->i_ino
= shp
->shm_perm
.id
;
414 ns
->shm_tot
+= numpages
;
415 error
= shp
->shm_perm
.id
;
422 security_shm_free(shp
);
427 static inline int shm_security(void *shp
, int shmflg
)
429 return security_shm_associate((struct shmid_kernel
*) shp
, shmflg
);
432 static inline int shm_more_checks(void *shp
, struct ipc_params
*params
)
434 if (((struct shmid_kernel
*)shp
)->shm_segsz
< params
->u
.size
)
440 asmlinkage
long sys_shmget (key_t key
, size_t size
, int shmflg
)
442 struct ipc_namespace
*ns
;
443 struct ipc_ops shm_ops
;
444 struct ipc_params shm_params
;
446 ns
= current
->nsproxy
->ipc_ns
;
448 shm_ops
.getnew
= newseg
;
449 shm_ops
.associate
= shm_security
;
450 shm_ops
.more_checks
= shm_more_checks
;
452 shm_params
.key
= key
;
453 shm_params
.flg
= shmflg
;
454 shm_params
.u
.size
= size
;
456 return ipcget(ns
, &shm_ids(ns
), &shm_ops
, &shm_params
);
459 static inline unsigned long copy_shmid_to_user(void __user
*buf
, struct shmid64_ds
*in
, int version
)
463 return copy_to_user(buf
, in
, sizeof(*in
));
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
));
490 static inline unsigned long copy_shmid_from_user(struct shm_setbuf
*out
, void __user
*buf
, int version
)
495 struct shmid64_ds tbuf
;
497 if (copy_from_user(&tbuf
, buf
, sizeof(tbuf
)))
500 out
->uid
= tbuf
.shm_perm
.uid
;
501 out
->gid
= tbuf
.shm_perm
.gid
;
502 out
->mode
= tbuf
.shm_perm
.mode
;
508 struct shmid_ds tbuf_old
;
510 if (copy_from_user(&tbuf_old
, buf
, sizeof(tbuf_old
)))
513 out
->uid
= tbuf_old
.shm_perm
.uid
;
514 out
->gid
= tbuf_old
.shm_perm
.gid
;
515 out
->mode
= tbuf_old
.shm_perm
.mode
;
524 static inline unsigned long copy_shminfo_to_user(void __user
*buf
, struct shminfo64
*in
, int version
)
528 return copy_to_user(buf
, in
, sizeof(*in
));
533 if(in
->shmmax
> INT_MAX
)
534 out
.shmmax
= INT_MAX
;
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
));
550 static void shm_get_stat(struct ipc_namespace
*ns
, unsigned long *rss
,
559 in_use
= shm_ids(ns
).in_use
;
561 for (total
= 0, next_id
= 0; total
< in_use
; next_id
++) {
562 struct shmid_kernel
*shp
;
566 * idr_find() is called via shm_get(), so with shm_ids.mutex
567 * locked. Since ipc_addid() is also called with
568 * shm_ids.mutex down, there is no need to add read barriers
569 * here to gurantee the writes in ipc_addid() are seen in
570 * order here (for Alpha).
571 * However idr_find() itself does not necessary require
572 * ipc_ids.mutex down. So if idr_find() is used by other
573 * places without ipc_ids.mutex down, then it needs read
574 * read memory barriers as ipc_lock() does.
577 shp
= idr_find(&shm_ids(ns
).ipcs_idr
, next_id
);
581 inode
= shp
->shm_file
->f_path
.dentry
->d_inode
;
583 if (is_file_hugepages(shp
->shm_file
)) {
584 struct address_space
*mapping
= inode
->i_mapping
;
585 *rss
+= (HPAGE_SIZE
/PAGE_SIZE
)*mapping
->nrpages
;
587 struct shmem_inode_info
*info
= SHMEM_I(inode
);
588 spin_lock(&info
->lock
);
589 *rss
+= inode
->i_mapping
->nrpages
;
590 *swp
+= info
->swapped
;
591 spin_unlock(&info
->lock
);
598 asmlinkage
long sys_shmctl (int shmid
, int cmd
, struct shmid_ds __user
*buf
)
600 struct shm_setbuf setbuf
;
601 struct shmid_kernel
*shp
;
603 struct ipc_namespace
*ns
;
605 if (cmd
< 0 || shmid
< 0) {
610 version
= ipc_parse_version(&cmd
);
611 ns
= current
->nsproxy
->ipc_ns
;
613 switch (cmd
) { /* replace with proc interface ? */
616 struct shminfo64 shminfo
;
618 err
= security_shm_shmctl(NULL
, cmd
);
622 memset(&shminfo
,0,sizeof(shminfo
));
623 shminfo
.shmmni
= shminfo
.shmseg
= ns
->shm_ctlmni
;
624 shminfo
.shmmax
= ns
->shm_ctlmax
;
625 shminfo
.shmall
= ns
->shm_ctlall
;
627 shminfo
.shmmin
= SHMMIN
;
628 if(copy_shminfo_to_user (buf
, &shminfo
, version
))
630 /* reading a integer is always atomic */
631 err
= ipc_get_maxid(&shm_ids(ns
));
638 struct shm_info shm_info
;
640 err
= security_shm_shmctl(NULL
, cmd
);
644 memset(&shm_info
,0,sizeof(shm_info
));
645 mutex_lock(&shm_ids(ns
).mutex
);
646 shm_info
.used_ids
= shm_ids(ns
).in_use
;
647 shm_get_stat (ns
, &shm_info
.shm_rss
, &shm_info
.shm_swp
);
648 shm_info
.shm_tot
= ns
->shm_tot
;
649 shm_info
.swap_attempts
= 0;
650 shm_info
.swap_successes
= 0;
651 err
= ipc_get_maxid(&shm_ids(ns
));
652 mutex_unlock(&shm_ids(ns
).mutex
);
653 if(copy_to_user (buf
, &shm_info
, sizeof(shm_info
))) {
658 err
= err
< 0 ? 0 : err
;
664 struct shmid64_ds tbuf
;
672 if (cmd
== SHM_STAT
) {
673 shp
= shm_lock(ns
, shmid
);
678 result
= shp
->shm_perm
.id
;
680 shp
= shm_lock_check(ns
, shmid
);
688 if (ipcperms (&shp
->shm_perm
, S_IRUGO
))
690 err
= security_shm_shmctl(shp
, cmd
);
693 memset(&tbuf
, 0, sizeof(tbuf
));
694 kernel_to_ipc64_perm(&shp
->shm_perm
, &tbuf
.shm_perm
);
695 tbuf
.shm_segsz
= shp
->shm_segsz
;
696 tbuf
.shm_atime
= shp
->shm_atim
;
697 tbuf
.shm_dtime
= shp
->shm_dtim
;
698 tbuf
.shm_ctime
= shp
->shm_ctim
;
699 tbuf
.shm_cpid
= shp
->shm_cprid
;
700 tbuf
.shm_lpid
= shp
->shm_lprid
;
701 tbuf
.shm_nattch
= shp
->shm_nattch
;
703 if(copy_shmid_to_user (buf
, &tbuf
, version
))
712 shp
= shm_lock_check(ns
, shmid
);
718 err
= audit_ipc_obj(&(shp
->shm_perm
));
722 if (!capable(CAP_IPC_LOCK
)) {
724 if (current
->euid
!= shp
->shm_perm
.uid
&&
725 current
->euid
!= shp
->shm_perm
.cuid
)
727 if (cmd
== SHM_LOCK
&&
728 !current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
)
732 err
= security_shm_shmctl(shp
, cmd
);
737 struct user_struct
* user
= current
->user
;
738 if (!is_file_hugepages(shp
->shm_file
)) {
739 err
= shmem_lock(shp
->shm_file
, 1, user
);
740 if (!err
&& !(shp
->shm_perm
.mode
& SHM_LOCKED
)){
741 shp
->shm_perm
.mode
|= SHM_LOCKED
;
742 shp
->mlock_user
= user
;
745 } else if (!is_file_hugepages(shp
->shm_file
)) {
746 shmem_lock(shp
->shm_file
, 0, shp
->mlock_user
);
747 shp
->shm_perm
.mode
&= ~SHM_LOCKED
;
748 shp
->mlock_user
= NULL
;
756 * We cannot simply remove the file. The SVID states
757 * that the block remains until the last person
758 * detaches from it, then is deleted. A shmat() on
759 * an RMID segment is legal in older Linux and if
760 * we change it apps break...
762 * Instead we set a destroyed flag, and then blow
763 * the name away when the usage hits zero.
765 mutex_lock(&shm_ids(ns
).mutex
);
766 shp
= shm_lock_check(ns
, shmid
);
772 err
= audit_ipc_obj(&(shp
->shm_perm
));
776 if (current
->euid
!= shp
->shm_perm
.uid
&&
777 current
->euid
!= shp
->shm_perm
.cuid
&&
778 !capable(CAP_SYS_ADMIN
)) {
783 err
= security_shm_shmctl(shp
, cmd
);
787 do_shm_rmid(ns
, shp
);
788 mutex_unlock(&shm_ids(ns
).mutex
);
799 if (copy_shmid_from_user (&setbuf
, buf
, version
)) {
803 mutex_lock(&shm_ids(ns
).mutex
);
804 shp
= shm_lock_check(ns
, shmid
);
809 err
= audit_ipc_obj(&(shp
->shm_perm
));
812 err
= audit_ipc_set_perm(0, setbuf
.uid
, setbuf
.gid
, setbuf
.mode
);
816 if (current
->euid
!= shp
->shm_perm
.uid
&&
817 current
->euid
!= shp
->shm_perm
.cuid
&&
818 !capable(CAP_SYS_ADMIN
)) {
822 err
= security_shm_shmctl(shp
, cmd
);
826 shp
->shm_perm
.uid
= setbuf
.uid
;
827 shp
->shm_perm
.gid
= setbuf
.gid
;
828 shp
->shm_perm
.mode
= (shp
->shm_perm
.mode
& ~S_IRWXUGO
)
829 | (setbuf
.mode
& S_IRWXUGO
);
830 shp
->shm_ctim
= get_seconds();
843 mutex_unlock(&shm_ids(ns
).mutex
);
852 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
854 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
855 * "raddr" thing points to kernel space, and there has to be a wrapper around
858 long do_shmat(int shmid
, char __user
*shmaddr
, int shmflg
, ulong
*raddr
)
860 struct shmid_kernel
*shp
;
868 unsigned long user_addr
;
869 struct ipc_namespace
*ns
;
870 struct shm_file_data
*sfd
;
877 else if ((addr
= (ulong
)shmaddr
)) {
878 if (addr
& (SHMLBA
-1)) {
879 if (shmflg
& SHM_RND
)
880 addr
&= ~(SHMLBA
-1); /* round down */
882 #ifndef __ARCH_FORCE_SHMLBA
883 if (addr
& ~PAGE_MASK
)
887 flags
= MAP_SHARED
| MAP_FIXED
;
889 if ((shmflg
& SHM_REMAP
))
895 if (shmflg
& SHM_RDONLY
) {
900 prot
= PROT_READ
| PROT_WRITE
;
901 acc_mode
= S_IRUGO
| S_IWUGO
;
902 f_mode
= FMODE_READ
| FMODE_WRITE
;
904 if (shmflg
& SHM_EXEC
) {
910 * We cannot rely on the fs check since SYSV IPC does have an
911 * additional creator id...
913 ns
= current
->nsproxy
->ipc_ns
;
914 shp
= shm_lock_check(ns
, shmid
);
921 if (ipcperms(&shp
->shm_perm
, acc_mode
))
924 err
= security_shm_shmat(shp
, shmaddr
, shmflg
);
928 path
.dentry
= dget(shp
->shm_file
->f_path
.dentry
);
929 path
.mnt
= shp
->shm_file
->f_path
.mnt
;
931 size
= i_size_read(path
.dentry
->d_inode
);
935 sfd
= kzalloc(sizeof(*sfd
), GFP_KERNEL
);
941 file
= alloc_file(path
.mnt
, path
.dentry
, f_mode
, &shm_file_operations
);
945 file
->private_data
= sfd
;
946 file
->f_mapping
= shp
->shm_file
->f_mapping
;
947 sfd
->id
= shp
->shm_perm
.id
;
948 sfd
->ns
= get_ipc_ns(ns
);
949 sfd
->file
= shp
->shm_file
;
952 down_write(¤t
->mm
->mmap_sem
);
953 if (addr
&& !(shmflg
& SHM_REMAP
)) {
955 if (find_vma_intersection(current
->mm
, addr
, addr
+ size
))
958 * If shm segment goes below stack, make sure there is some
959 * space left for the stack to grow (at least 4 pages).
961 if (addr
< current
->mm
->start_stack
&&
962 addr
> current
->mm
->start_stack
- size
- PAGE_SIZE
* 5)
966 user_addr
= do_mmap (file
, addr
, size
, prot
, flags
, 0);
969 if (IS_ERR_VALUE(user_addr
))
970 err
= (long)user_addr
;
972 up_write(¤t
->mm
->mmap_sem
);
977 mutex_lock(&shm_ids(ns
).mutex
);
978 shp
= shm_lock(ns
, shmid
);
981 if(shp
->shm_nattch
== 0 &&
982 shp
->shm_perm
.mode
& SHM_DEST
)
983 shm_destroy(ns
, shp
);
986 mutex_unlock(&shm_ids(ns
).mutex
);
1002 asmlinkage
long sys_shmat(int shmid
, char __user
*shmaddr
, int shmflg
)
1007 err
= do_shmat(shmid
, shmaddr
, shmflg
, &ret
);
1010 force_successful_syscall_return();
1015 * detach and kill segment if marked destroyed.
1016 * The work is done in shm_close.
1018 asmlinkage
long sys_shmdt(char __user
*shmaddr
)
1020 struct mm_struct
*mm
= current
->mm
;
1021 struct vm_area_struct
*vma
, *next
;
1022 unsigned long addr
= (unsigned long)shmaddr
;
1024 int retval
= -EINVAL
;
1026 if (addr
& ~PAGE_MASK
)
1029 down_write(&mm
->mmap_sem
);
1032 * This function tries to be smart and unmap shm segments that
1033 * were modified by partial mlock or munmap calls:
1034 * - It first determines the size of the shm segment that should be
1035 * unmapped: It searches for a vma that is backed by shm and that
1036 * started at address shmaddr. It records it's size and then unmaps
1038 * - Then it unmaps all shm vmas that started at shmaddr and that
1039 * are within the initially determined size.
1040 * Errors from do_munmap are ignored: the function only fails if
1041 * it's called with invalid parameters or if it's called to unmap
1042 * a part of a vma. Both calls in this function are for full vmas,
1043 * the parameters are directly copied from the vma itself and always
1044 * valid - therefore do_munmap cannot fail. (famous last words?)
1047 * If it had been mremap()'d, the starting address would not
1048 * match the usual checks anyway. So assume all vma's are
1049 * above the starting address given.
1051 vma
= find_vma(mm
, addr
);
1054 next
= vma
->vm_next
;
1057 * Check if the starting address would match, i.e. it's
1058 * a fragment created by mprotect() and/or munmap(), or it
1059 * otherwise it starts at this address with no hassles.
1061 if ((vma
->vm_ops
== &shm_vm_ops
) &&
1062 (vma
->vm_start
- addr
)/PAGE_SIZE
== vma
->vm_pgoff
) {
1065 size
= vma
->vm_file
->f_path
.dentry
->d_inode
->i_size
;
1066 do_munmap(mm
, vma
->vm_start
, vma
->vm_end
- vma
->vm_start
);
1068 * We discovered the size of the shm segment, so
1069 * break out of here and fall through to the next
1070 * loop that uses the size information to stop
1071 * searching for matching vma's.
1081 * We need look no further than the maximum address a fragment
1082 * could possibly have landed at. Also cast things to loff_t to
1083 * prevent overflows and make comparisions vs. equal-width types.
1085 size
= PAGE_ALIGN(size
);
1086 while (vma
&& (loff_t
)(vma
->vm_end
- addr
) <= size
) {
1087 next
= vma
->vm_next
;
1089 /* finding a matching vma now does not alter retval */
1090 if ((vma
->vm_ops
== &shm_vm_ops
) &&
1091 (vma
->vm_start
- addr
)/PAGE_SIZE
== vma
->vm_pgoff
)
1093 do_munmap(mm
, vma
->vm_start
, vma
->vm_end
- vma
->vm_start
);
1097 up_write(&mm
->mmap_sem
);
1101 #ifdef CONFIG_PROC_FS
1102 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
)
1104 struct shmid_kernel
*shp
= it
;
1107 #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1108 #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1110 if (sizeof(size_t) <= sizeof(int))
1111 format
= SMALL_STRING
;
1113 format
= BIG_STRING
;
1114 return seq_printf(s
, format
,