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/rwsem.h>
39 #include <linux/nsproxy.h>
40 #include <linux/mount.h>
41 #include <linux/ipc_namespace.h>
43 #include <asm/uaccess.h>
47 struct shm_file_data
{
49 struct ipc_namespace
*ns
;
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 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
);
69 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
);
72 void shm_init_ns(struct ipc_namespace
*ns
)
74 ns
->shm_ctlmax
= SHMMAX
;
75 ns
->shm_ctlall
= SHMALL
;
76 ns
->shm_ctlmni
= SHMMNI
;
78 ipc_init_ids(&ns
->ids
[IPC_SHM_IDS
]);
82 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
83 * Only shm_ids.rw_mutex remains locked on exit.
85 static void do_shm_rmid(struct ipc_namespace
*ns
, struct kern_ipc_perm
*ipcp
)
87 struct shmid_kernel
*shp
;
88 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
91 shp
->shm_perm
.mode
|= SHM_DEST
;
92 /* Do not find it any more */
93 shp
->shm_perm
.key
= IPC_PRIVATE
;
100 void shm_exit_ns(struct ipc_namespace
*ns
)
102 free_ipcs(ns
, &shm_ids(ns
), do_shm_rmid
);
106 void __init
shm_init (void)
108 shm_init_ns(&init_ipc_ns
);
109 ipc_init_proc_interface("sysvipc/shm",
110 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
111 IPC_SHM_IDS
, sysvipc_shm_proc_show
);
115 * shm_lock_(check_)down routines are called in the paths where the rw_mutex
116 * is held to protect access to the idr tree.
118 static inline struct shmid_kernel
*shm_lock_down(struct ipc_namespace
*ns
,
121 struct kern_ipc_perm
*ipcp
= ipc_lock_down(&shm_ids(ns
), id
);
124 return (struct shmid_kernel
*)ipcp
;
126 return container_of(ipcp
, struct shmid_kernel
, shm_perm
);
129 static inline struct shmid_kernel
*shm_lock_check_down(
130 struct ipc_namespace
*ns
,
133 struct kern_ipc_perm
*ipcp
= ipc_lock_check_down(&shm_ids(ns
), id
);
136 return (struct shmid_kernel
*)ipcp
;
138 return container_of(ipcp
, struct shmid_kernel
, shm_perm
);
142 * shm_lock_(check_) routines are called in the paths where the rw_mutex
145 static inline struct shmid_kernel
*shm_lock(struct ipc_namespace
*ns
, int id
)
147 struct kern_ipc_perm
*ipcp
= ipc_lock(&shm_ids(ns
), id
);
150 return (struct shmid_kernel
*)ipcp
;
152 return container_of(ipcp
, struct shmid_kernel
, shm_perm
);
155 static inline struct shmid_kernel
*shm_lock_check(struct ipc_namespace
*ns
,
158 struct kern_ipc_perm
*ipcp
= ipc_lock_check(&shm_ids(ns
), id
);
161 return (struct shmid_kernel
*)ipcp
;
163 return container_of(ipcp
, struct shmid_kernel
, shm_perm
);
166 static inline void shm_rmid(struct ipc_namespace
*ns
, struct shmid_kernel
*s
)
168 ipc_rmid(&shm_ids(ns
), &s
->shm_perm
);
172 /* This is called by fork, once for every shm attach. */
173 static void shm_open(struct vm_area_struct
*vma
)
175 struct file
*file
= vma
->vm_file
;
176 struct shm_file_data
*sfd
= shm_file_data(file
);
177 struct shmid_kernel
*shp
;
179 shp
= shm_lock(sfd
->ns
, sfd
->id
);
181 shp
->shm_atim
= get_seconds();
182 shp
->shm_lprid
= task_tgid_vnr(current
);
188 * shm_destroy - free the struct shmid_kernel
191 * @shp: struct to free
193 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
194 * but returns with shp unlocked and freed.
196 static void shm_destroy(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
198 ns
->shm_tot
-= (shp
->shm_segsz
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
201 if (!is_file_hugepages(shp
->shm_file
))
202 shmem_lock(shp
->shm_file
, 0, shp
->mlock_user
);
204 user_shm_unlock(shp
->shm_file
->f_path
.dentry
->d_inode
->i_size
,
206 fput (shp
->shm_file
);
207 security_shm_free(shp
);
212 * remove the attach descriptor vma.
213 * free memory for segment if it is marked destroyed.
214 * The descriptor has already been removed from the current->mm->mmap list
215 * and will later be kfree()d.
217 static void shm_close(struct vm_area_struct
*vma
)
219 struct file
* file
= vma
->vm_file
;
220 struct shm_file_data
*sfd
= shm_file_data(file
);
221 struct shmid_kernel
*shp
;
222 struct ipc_namespace
*ns
= sfd
->ns
;
224 down_write(&shm_ids(ns
).rw_mutex
);
225 /* remove from the list of attaches of the shm segment */
226 shp
= shm_lock_down(ns
, sfd
->id
);
228 shp
->shm_lprid
= task_tgid_vnr(current
);
229 shp
->shm_dtim
= get_seconds();
231 if(shp
->shm_nattch
== 0 &&
232 shp
->shm_perm
.mode
& SHM_DEST
)
233 shm_destroy(ns
, shp
);
236 up_write(&shm_ids(ns
).rw_mutex
);
239 static int shm_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
241 struct file
*file
= vma
->vm_file
;
242 struct shm_file_data
*sfd
= shm_file_data(file
);
244 return sfd
->vm_ops
->fault(vma
, vmf
);
248 static int shm_set_policy(struct vm_area_struct
*vma
, struct mempolicy
*new)
250 struct file
*file
= vma
->vm_file
;
251 struct shm_file_data
*sfd
= shm_file_data(file
);
253 if (sfd
->vm_ops
->set_policy
)
254 err
= sfd
->vm_ops
->set_policy(vma
, new);
258 static struct mempolicy
*shm_get_policy(struct vm_area_struct
*vma
,
261 struct file
*file
= vma
->vm_file
;
262 struct shm_file_data
*sfd
= shm_file_data(file
);
263 struct mempolicy
*pol
= NULL
;
265 if (sfd
->vm_ops
->get_policy
)
266 pol
= sfd
->vm_ops
->get_policy(vma
, addr
);
267 else if (vma
->vm_policy
)
268 pol
= vma
->vm_policy
;
274 static int shm_mmap(struct file
* file
, struct vm_area_struct
* vma
)
276 struct shm_file_data
*sfd
= shm_file_data(file
);
279 ret
= sfd
->file
->f_op
->mmap(sfd
->file
, vma
);
282 sfd
->vm_ops
= vma
->vm_ops
;
284 BUG_ON(!sfd
->vm_ops
->fault
);
286 vma
->vm_ops
= &shm_vm_ops
;
292 static int shm_release(struct inode
*ino
, struct file
*file
)
294 struct shm_file_data
*sfd
= shm_file_data(file
);
297 shm_file_data(file
) = NULL
;
302 static int shm_fsync(struct file
*file
, struct dentry
*dentry
, int datasync
)
304 int (*fsync
) (struct file
*, struct dentry
*, int datasync
);
305 struct shm_file_data
*sfd
= shm_file_data(file
);
308 fsync
= sfd
->file
->f_op
->fsync
;
310 ret
= fsync(sfd
->file
, sfd
->file
->f_path
.dentry
, datasync
);
314 static unsigned long shm_get_unmapped_area(struct file
*file
,
315 unsigned long addr
, unsigned long len
, unsigned long pgoff
,
318 struct shm_file_data
*sfd
= shm_file_data(file
);
319 return get_unmapped_area(sfd
->file
, addr
, len
, pgoff
, flags
);
322 int is_file_shm_hugepages(struct file
*file
)
326 if (file
->f_op
== &shm_file_operations
) {
327 struct shm_file_data
*sfd
;
328 sfd
= shm_file_data(file
);
329 ret
= is_file_hugepages(sfd
->file
);
334 static const struct file_operations shm_file_operations
= {
337 .release
= shm_release
,
338 .get_unmapped_area
= shm_get_unmapped_area
,
341 static struct vm_operations_struct shm_vm_ops
= {
342 .open
= shm_open
, /* callback for a new vm-area open */
343 .close
= shm_close
, /* callback for when the vm-area is released */
345 #if defined(CONFIG_NUMA)
346 .set_policy
= shm_set_policy
,
347 .get_policy
= shm_get_policy
,
352 * newseg - Create a new shared memory segment
354 * @params: ptr to the structure that contains key, size and shmflg
356 * Called with shm_ids.rw_mutex held as a writer.
359 static int newseg(struct ipc_namespace
*ns
, struct ipc_params
*params
)
361 key_t key
= params
->key
;
362 int shmflg
= params
->flg
;
363 size_t size
= params
->u
.size
;
365 struct shmid_kernel
*shp
;
366 int numpages
= (size
+ PAGE_SIZE
-1) >> PAGE_SHIFT
;
371 if (size
< SHMMIN
|| size
> ns
->shm_ctlmax
)
374 if (ns
->shm_tot
+ numpages
> ns
->shm_ctlall
)
377 shp
= ipc_rcu_alloc(sizeof(*shp
));
381 shp
->shm_perm
.key
= key
;
382 shp
->shm_perm
.mode
= (shmflg
& S_IRWXUGO
);
383 shp
->mlock_user
= NULL
;
385 shp
->shm_perm
.security
= NULL
;
386 error
= security_shm_alloc(shp
);
392 sprintf (name
, "SYSV%08x", key
);
393 if (shmflg
& SHM_HUGETLB
) {
394 /* hugetlb_file_setup takes care of mlock user accounting */
395 file
= hugetlb_file_setup(name
, size
);
396 shp
->mlock_user
= current
->user
;
398 int acctflag
= VM_ACCOUNT
;
400 * Do not allow no accounting for OVERCOMMIT_NEVER, even
403 if ((shmflg
& SHM_NORESERVE
) &&
404 sysctl_overcommit_memory
!= OVERCOMMIT_NEVER
)
406 file
= shmem_file_setup(name
, size
, acctflag
);
408 error
= PTR_ERR(file
);
412 id
= ipc_addid(&shm_ids(ns
), &shp
->shm_perm
, ns
->shm_ctlmni
);
418 shp
->shm_cprid
= task_tgid_vnr(current
);
420 shp
->shm_atim
= shp
->shm_dtim
= 0;
421 shp
->shm_ctim
= get_seconds();
422 shp
->shm_segsz
= size
;
424 shp
->shm_file
= file
;
426 * shmid gets reported as "inode#" in /proc/pid/maps.
427 * proc-ps tools use this. Changing this will break them.
429 file
->f_dentry
->d_inode
->i_ino
= shp
->shm_perm
.id
;
431 ns
->shm_tot
+= numpages
;
432 error
= shp
->shm_perm
.id
;
439 security_shm_free(shp
);
445 * Called with shm_ids.rw_mutex and ipcp locked.
447 static inline int shm_security(struct kern_ipc_perm
*ipcp
, int shmflg
)
449 struct shmid_kernel
*shp
;
451 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
452 return security_shm_associate(shp
, shmflg
);
456 * Called with shm_ids.rw_mutex and ipcp locked.
458 static inline int shm_more_checks(struct kern_ipc_perm
*ipcp
,
459 struct ipc_params
*params
)
461 struct shmid_kernel
*shp
;
463 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
464 if (shp
->shm_segsz
< params
->u
.size
)
470 asmlinkage
long sys_shmget (key_t key
, size_t size
, int shmflg
)
472 struct ipc_namespace
*ns
;
473 struct ipc_ops shm_ops
;
474 struct ipc_params shm_params
;
476 ns
= current
->nsproxy
->ipc_ns
;
478 shm_ops
.getnew
= newseg
;
479 shm_ops
.associate
= shm_security
;
480 shm_ops
.more_checks
= shm_more_checks
;
482 shm_params
.key
= key
;
483 shm_params
.flg
= shmflg
;
484 shm_params
.u
.size
= size
;
486 return ipcget(ns
, &shm_ids(ns
), &shm_ops
, &shm_params
);
489 static inline unsigned long copy_shmid_to_user(void __user
*buf
, struct shmid64_ds
*in
, int version
)
493 return copy_to_user(buf
, in
, sizeof(*in
));
498 ipc64_perm_to_ipc_perm(&in
->shm_perm
, &out
.shm_perm
);
499 out
.shm_segsz
= in
->shm_segsz
;
500 out
.shm_atime
= in
->shm_atime
;
501 out
.shm_dtime
= in
->shm_dtime
;
502 out
.shm_ctime
= in
->shm_ctime
;
503 out
.shm_cpid
= in
->shm_cpid
;
504 out
.shm_lpid
= in
->shm_lpid
;
505 out
.shm_nattch
= in
->shm_nattch
;
507 return copy_to_user(buf
, &out
, sizeof(out
));
520 static inline unsigned long copy_shmid_from_user(struct shm_setbuf
*out
, void __user
*buf
, int version
)
525 struct shmid64_ds tbuf
;
527 if (copy_from_user(&tbuf
, buf
, sizeof(tbuf
)))
530 out
->uid
= tbuf
.shm_perm
.uid
;
531 out
->gid
= tbuf
.shm_perm
.gid
;
532 out
->mode
= tbuf
.shm_perm
.mode
;
538 struct shmid_ds tbuf_old
;
540 if (copy_from_user(&tbuf_old
, buf
, sizeof(tbuf_old
)))
543 out
->uid
= tbuf_old
.shm_perm
.uid
;
544 out
->gid
= tbuf_old
.shm_perm
.gid
;
545 out
->mode
= tbuf_old
.shm_perm
.mode
;
554 static inline unsigned long copy_shminfo_to_user(void __user
*buf
, struct shminfo64
*in
, int version
)
558 return copy_to_user(buf
, in
, sizeof(*in
));
563 if(in
->shmmax
> INT_MAX
)
564 out
.shmmax
= INT_MAX
;
566 out
.shmmax
= (int)in
->shmmax
;
568 out
.shmmin
= in
->shmmin
;
569 out
.shmmni
= in
->shmmni
;
570 out
.shmseg
= in
->shmseg
;
571 out
.shmall
= in
->shmall
;
573 return copy_to_user(buf
, &out
, sizeof(out
));
581 * Called with shm_ids.rw_mutex held as a reader
583 static void shm_get_stat(struct ipc_namespace
*ns
, unsigned long *rss
,
592 in_use
= shm_ids(ns
).in_use
;
594 for (total
= 0, next_id
= 0; total
< in_use
; next_id
++) {
595 struct shmid_kernel
*shp
;
598 shp
= idr_find(&shm_ids(ns
).ipcs_idr
, next_id
);
602 inode
= shp
->shm_file
->f_path
.dentry
->d_inode
;
604 if (is_file_hugepages(shp
->shm_file
)) {
605 struct address_space
*mapping
= inode
->i_mapping
;
606 *rss
+= (HPAGE_SIZE
/PAGE_SIZE
)*mapping
->nrpages
;
608 struct shmem_inode_info
*info
= SHMEM_I(inode
);
609 spin_lock(&info
->lock
);
610 *rss
+= inode
->i_mapping
->nrpages
;
611 *swp
+= info
->swapped
;
612 spin_unlock(&info
->lock
);
620 * This function handles some shmctl commands which require the rw_mutex
621 * to be held in write mode.
622 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
624 static int shmctl_down(struct ipc_namespace
*ns
, int shmid
, int cmd
,
625 struct shmid_ds __user
*buf
, int version
)
627 struct kern_ipc_perm
*ipcp
;
628 struct shm_setbuf setbuf
;
629 struct shmid_kernel
*shp
;
632 if (cmd
== IPC_SET
) {
633 if (copy_shmid_from_user(&setbuf
, buf
, version
))
637 down_write(&shm_ids(ns
).rw_mutex
);
638 shp
= shm_lock_check_down(ns
, shmid
);
644 ipcp
= &shp
->shm_perm
;
646 err
= audit_ipc_obj(ipcp
);
650 if (cmd
== IPC_SET
) {
651 err
= audit_ipc_set_perm(0, setbuf
.uid
,
652 setbuf
.gid
, setbuf
.mode
);
657 if (current
->euid
!= ipcp
->uid
&&
658 current
->euid
!= ipcp
->cuid
&&
659 !capable(CAP_SYS_ADMIN
)) {
664 err
= security_shm_shmctl(shp
, cmd
);
669 do_shm_rmid(ns
, ipcp
);
672 ipcp
->uid
= setbuf
.uid
;
673 ipcp
->gid
= setbuf
.gid
;
674 ipcp
->mode
= (ipcp
->mode
& ~S_IRWXUGO
)
675 | (setbuf
.mode
& S_IRWXUGO
);
676 shp
->shm_ctim
= get_seconds();
684 up_write(&shm_ids(ns
).rw_mutex
);
688 asmlinkage
long sys_shmctl(int shmid
, int cmd
, struct shmid_ds __user
*buf
)
690 struct shmid_kernel
*shp
;
692 struct ipc_namespace
*ns
;
694 if (cmd
< 0 || shmid
< 0) {
699 version
= ipc_parse_version(&cmd
);
700 ns
= current
->nsproxy
->ipc_ns
;
702 switch (cmd
) { /* replace with proc interface ? */
705 struct shminfo64 shminfo
;
707 err
= security_shm_shmctl(NULL
, cmd
);
711 memset(&shminfo
,0,sizeof(shminfo
));
712 shminfo
.shmmni
= shminfo
.shmseg
= ns
->shm_ctlmni
;
713 shminfo
.shmmax
= ns
->shm_ctlmax
;
714 shminfo
.shmall
= ns
->shm_ctlall
;
716 shminfo
.shmmin
= SHMMIN
;
717 if(copy_shminfo_to_user (buf
, &shminfo
, version
))
720 down_read(&shm_ids(ns
).rw_mutex
);
721 err
= ipc_get_maxid(&shm_ids(ns
));
722 up_read(&shm_ids(ns
).rw_mutex
);
730 struct shm_info shm_info
;
732 err
= security_shm_shmctl(NULL
, cmd
);
736 memset(&shm_info
,0,sizeof(shm_info
));
737 down_read(&shm_ids(ns
).rw_mutex
);
738 shm_info
.used_ids
= shm_ids(ns
).in_use
;
739 shm_get_stat (ns
, &shm_info
.shm_rss
, &shm_info
.shm_swp
);
740 shm_info
.shm_tot
= ns
->shm_tot
;
741 shm_info
.swap_attempts
= 0;
742 shm_info
.swap_successes
= 0;
743 err
= ipc_get_maxid(&shm_ids(ns
));
744 up_read(&shm_ids(ns
).rw_mutex
);
745 if(copy_to_user (buf
, &shm_info
, sizeof(shm_info
))) {
750 err
= err
< 0 ? 0 : err
;
756 struct shmid64_ds tbuf
;
764 if (cmd
== SHM_STAT
) {
765 shp
= shm_lock(ns
, shmid
);
770 result
= shp
->shm_perm
.id
;
772 shp
= shm_lock_check(ns
, shmid
);
780 if (ipcperms (&shp
->shm_perm
, S_IRUGO
))
782 err
= security_shm_shmctl(shp
, cmd
);
785 memset(&tbuf
, 0, sizeof(tbuf
));
786 kernel_to_ipc64_perm(&shp
->shm_perm
, &tbuf
.shm_perm
);
787 tbuf
.shm_segsz
= shp
->shm_segsz
;
788 tbuf
.shm_atime
= shp
->shm_atim
;
789 tbuf
.shm_dtime
= shp
->shm_dtim
;
790 tbuf
.shm_ctime
= shp
->shm_ctim
;
791 tbuf
.shm_cpid
= shp
->shm_cprid
;
792 tbuf
.shm_lpid
= shp
->shm_lprid
;
793 tbuf
.shm_nattch
= shp
->shm_nattch
;
795 if(copy_shmid_to_user (buf
, &tbuf
, version
))
804 shp
= shm_lock_check(ns
, shmid
);
810 err
= audit_ipc_obj(&(shp
->shm_perm
));
814 if (!capable(CAP_IPC_LOCK
)) {
816 if (current
->euid
!= shp
->shm_perm
.uid
&&
817 current
->euid
!= shp
->shm_perm
.cuid
)
819 if (cmd
== SHM_LOCK
&&
820 !current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
)
824 err
= security_shm_shmctl(shp
, cmd
);
829 struct user_struct
* user
= current
->user
;
830 if (!is_file_hugepages(shp
->shm_file
)) {
831 err
= shmem_lock(shp
->shm_file
, 1, user
);
832 if (!err
&& !(shp
->shm_perm
.mode
& SHM_LOCKED
)){
833 shp
->shm_perm
.mode
|= SHM_LOCKED
;
834 shp
->mlock_user
= user
;
837 } else if (!is_file_hugepages(shp
->shm_file
)) {
838 shmem_lock(shp
->shm_file
, 0, shp
->mlock_user
);
839 shp
->shm_perm
.mode
&= ~SHM_LOCKED
;
840 shp
->mlock_user
= NULL
;
847 err
= shmctl_down(ns
, shmid
, cmd
, buf
, version
);
860 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
862 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
863 * "raddr" thing points to kernel space, and there has to be a wrapper around
866 long do_shmat(int shmid
, char __user
*shmaddr
, int shmflg
, ulong
*raddr
)
868 struct shmid_kernel
*shp
;
876 unsigned long user_addr
;
877 struct ipc_namespace
*ns
;
878 struct shm_file_data
*sfd
;
885 else if ((addr
= (ulong
)shmaddr
)) {
886 if (addr
& (SHMLBA
-1)) {
887 if (shmflg
& SHM_RND
)
888 addr
&= ~(SHMLBA
-1); /* round down */
890 #ifndef __ARCH_FORCE_SHMLBA
891 if (addr
& ~PAGE_MASK
)
895 flags
= MAP_SHARED
| MAP_FIXED
;
897 if ((shmflg
& SHM_REMAP
))
903 if (shmflg
& SHM_RDONLY
) {
908 prot
= PROT_READ
| PROT_WRITE
;
909 acc_mode
= S_IRUGO
| S_IWUGO
;
910 f_mode
= FMODE_READ
| FMODE_WRITE
;
912 if (shmflg
& SHM_EXEC
) {
918 * We cannot rely on the fs check since SYSV IPC does have an
919 * additional creator id...
921 ns
= current
->nsproxy
->ipc_ns
;
922 shp
= shm_lock_check(ns
, shmid
);
929 if (ipcperms(&shp
->shm_perm
, acc_mode
))
932 err
= security_shm_shmat(shp
, shmaddr
, shmflg
);
936 path
.dentry
= dget(shp
->shm_file
->f_path
.dentry
);
937 path
.mnt
= shp
->shm_file
->f_path
.mnt
;
939 size
= i_size_read(path
.dentry
->d_inode
);
943 sfd
= kzalloc(sizeof(*sfd
), GFP_KERNEL
);
949 file
= alloc_file(path
.mnt
, path
.dentry
, f_mode
, &shm_file_operations
);
953 file
->private_data
= sfd
;
954 file
->f_mapping
= shp
->shm_file
->f_mapping
;
955 sfd
->id
= shp
->shm_perm
.id
;
956 sfd
->ns
= get_ipc_ns(ns
);
957 sfd
->file
= shp
->shm_file
;
960 down_write(¤t
->mm
->mmap_sem
);
961 if (addr
&& !(shmflg
& SHM_REMAP
)) {
963 if (find_vma_intersection(current
->mm
, addr
, addr
+ size
))
966 * If shm segment goes below stack, make sure there is some
967 * space left for the stack to grow (at least 4 pages).
969 if (addr
< current
->mm
->start_stack
&&
970 addr
> current
->mm
->start_stack
- size
- PAGE_SIZE
* 5)
974 user_addr
= do_mmap (file
, addr
, size
, prot
, flags
, 0);
977 if (IS_ERR_VALUE(user_addr
))
978 err
= (long)user_addr
;
980 up_write(¤t
->mm
->mmap_sem
);
985 down_write(&shm_ids(ns
).rw_mutex
);
986 shp
= shm_lock_down(ns
, shmid
);
989 if(shp
->shm_nattch
== 0 &&
990 shp
->shm_perm
.mode
& SHM_DEST
)
991 shm_destroy(ns
, shp
);
994 up_write(&shm_ids(ns
).rw_mutex
);
1010 asmlinkage
long sys_shmat(int shmid
, char __user
*shmaddr
, int shmflg
)
1015 err
= do_shmat(shmid
, shmaddr
, shmflg
, &ret
);
1018 force_successful_syscall_return();
1023 * detach and kill segment if marked destroyed.
1024 * The work is done in shm_close.
1026 asmlinkage
long sys_shmdt(char __user
*shmaddr
)
1028 struct mm_struct
*mm
= current
->mm
;
1029 struct vm_area_struct
*vma
, *next
;
1030 unsigned long addr
= (unsigned long)shmaddr
;
1032 int retval
= -EINVAL
;
1034 if (addr
& ~PAGE_MASK
)
1037 down_write(&mm
->mmap_sem
);
1040 * This function tries to be smart and unmap shm segments that
1041 * were modified by partial mlock or munmap calls:
1042 * - It first determines the size of the shm segment that should be
1043 * unmapped: It searches for a vma that is backed by shm and that
1044 * started at address shmaddr. It records it's size and then unmaps
1046 * - Then it unmaps all shm vmas that started at shmaddr and that
1047 * are within the initially determined size.
1048 * Errors from do_munmap are ignored: the function only fails if
1049 * it's called with invalid parameters or if it's called to unmap
1050 * a part of a vma. Both calls in this function are for full vmas,
1051 * the parameters are directly copied from the vma itself and always
1052 * valid - therefore do_munmap cannot fail. (famous last words?)
1055 * If it had been mremap()'d, the starting address would not
1056 * match the usual checks anyway. So assume all vma's are
1057 * above the starting address given.
1059 vma
= find_vma(mm
, addr
);
1062 next
= vma
->vm_next
;
1065 * Check if the starting address would match, i.e. it's
1066 * a fragment created by mprotect() and/or munmap(), or it
1067 * otherwise it starts at this address with no hassles.
1069 if ((vma
->vm_ops
== &shm_vm_ops
) &&
1070 (vma
->vm_start
- addr
)/PAGE_SIZE
== vma
->vm_pgoff
) {
1073 size
= vma
->vm_file
->f_path
.dentry
->d_inode
->i_size
;
1074 do_munmap(mm
, vma
->vm_start
, vma
->vm_end
- vma
->vm_start
);
1076 * We discovered the size of the shm segment, so
1077 * break out of here and fall through to the next
1078 * loop that uses the size information to stop
1079 * searching for matching vma's.
1089 * We need look no further than the maximum address a fragment
1090 * could possibly have landed at. Also cast things to loff_t to
1091 * prevent overflows and make comparisions vs. equal-width types.
1093 size
= PAGE_ALIGN(size
);
1094 while (vma
&& (loff_t
)(vma
->vm_end
- addr
) <= size
) {
1095 next
= vma
->vm_next
;
1097 /* finding a matching vma now does not alter retval */
1098 if ((vma
->vm_ops
== &shm_vm_ops
) &&
1099 (vma
->vm_start
- addr
)/PAGE_SIZE
== vma
->vm_pgoff
)
1101 do_munmap(mm
, vma
->vm_start
, vma
->vm_end
- vma
->vm_start
);
1105 up_write(&mm
->mmap_sem
);
1109 #ifdef CONFIG_PROC_FS
1110 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
)
1112 struct shmid_kernel
*shp
= it
;
1115 #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1116 #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1118 if (sizeof(size_t) <= sizeof(int))
1119 format
= SMALL_STRING
;
1121 format
= BIG_STRING
;
1122 return seq_printf(s
, format
,