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_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
*, struct ipc_params
*);
72 static void shm_open(struct vm_area_struct
*vma
);
73 static void shm_close(struct vm_area_struct
*vma
);
74 static void shm_destroy (struct ipc_namespace
*ns
, struct shmid_kernel
*shp
);
76 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
);
79 static void __shm_init_ns(struct ipc_namespace
*ns
, struct ipc_ids
*ids
)
81 ns
->ids
[IPC_SHM_IDS
] = ids
;
82 ns
->shm_ctlmax
= SHMMAX
;
83 ns
->shm_ctlall
= SHMALL
;
84 ns
->shm_ctlmni
= SHMMNI
;
89 static void do_shm_rmid(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
92 shp
->shm_perm
.mode
|= SHM_DEST
;
93 /* Do not find it any more */
94 shp
->shm_perm
.key
= IPC_PRIVATE
;
100 int shm_init_ns(struct ipc_namespace
*ns
)
104 ids
= kmalloc(sizeof(struct ipc_ids
), GFP_KERNEL
);
108 __shm_init_ns(ns
, ids
);
112 void shm_exit_ns(struct ipc_namespace
*ns
)
114 struct shmid_kernel
*shp
;
118 mutex_lock(&shm_ids(ns
).mutex
);
120 in_use
= shm_ids(ns
).in_use
;
122 for (total
= 0, next_id
= 0; total
< in_use
; next_id
++) {
123 shp
= idr_find(&shm_ids(ns
).ipcs_idr
, next_id
);
126 ipc_lock_by_ptr(&shp
->shm_perm
);
127 do_shm_rmid(ns
, shp
);
130 mutex_unlock(&shm_ids(ns
).mutex
);
132 kfree(ns
->ids
[IPC_SHM_IDS
]);
133 ns
->ids
[IPC_SHM_IDS
] = NULL
;
136 void __init
shm_init (void)
138 __shm_init_ns(&init_ipc_ns
, &init_shm_ids
);
139 ipc_init_proc_interface("sysvipc/shm",
140 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
141 IPC_SHM_IDS
, sysvipc_shm_proc_show
);
144 static inline int shm_checkid(struct ipc_namespace
*ns
,
145 struct shmid_kernel
*s
, int id
)
147 if (ipc_checkid(&shm_ids(ns
), &s
->shm_perm
, id
))
152 static inline void shm_rmid(struct ipc_namespace
*ns
, struct shmid_kernel
*s
)
154 ipc_rmid(&shm_ids(ns
), &s
->shm_perm
);
157 static inline int shm_addid(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
159 return ipc_addid(&shm_ids(ns
), &shp
->shm_perm
, ns
->shm_ctlmni
);
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
);
173 shp
->shm_atim
= get_seconds();
174 shp
->shm_lprid
= task_tgid_vnr(current
);
180 * shm_destroy - free the struct shmid_kernel
182 * @shp: struct to free
184 * It has to be called with shp and shm_ids.mutex locked,
185 * but returns with shp unlocked and freed.
187 static void shm_destroy(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
189 ns
->shm_tot
-= (shp
->shm_segsz
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
192 if (!is_file_hugepages(shp
->shm_file
))
193 shmem_lock(shp
->shm_file
, 0, shp
->mlock_user
);
195 user_shm_unlock(shp
->shm_file
->f_path
.dentry
->d_inode
->i_size
,
197 fput (shp
->shm_file
);
198 security_shm_free(shp
);
203 * remove the attach descriptor vma.
204 * free memory for segment if it is marked destroyed.
205 * The descriptor has already been removed from the current->mm->mmap list
206 * and will later be kfree()d.
208 static void shm_close(struct vm_area_struct
*vma
)
210 struct file
* file
= vma
->vm_file
;
211 struct shm_file_data
*sfd
= shm_file_data(file
);
212 struct shmid_kernel
*shp
;
213 struct ipc_namespace
*ns
= sfd
->ns
;
215 mutex_lock(&shm_ids(ns
).mutex
);
216 /* remove from the list of attaches of the shm segment */
217 shp
= shm_lock(ns
, sfd
->id
);
219 shp
->shm_lprid
= task_tgid_vnr(current
);
220 shp
->shm_dtim
= get_seconds();
222 if(shp
->shm_nattch
== 0 &&
223 shp
->shm_perm
.mode
& SHM_DEST
)
224 shm_destroy(ns
, shp
);
227 mutex_unlock(&shm_ids(ns
).mutex
);
230 static int shm_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
232 struct file
*file
= vma
->vm_file
;
233 struct shm_file_data
*sfd
= shm_file_data(file
);
235 return sfd
->vm_ops
->fault(vma
, vmf
);
239 static int shm_set_policy(struct vm_area_struct
*vma
, struct mempolicy
*new)
241 struct file
*file
= vma
->vm_file
;
242 struct shm_file_data
*sfd
= shm_file_data(file
);
244 if (sfd
->vm_ops
->set_policy
)
245 err
= sfd
->vm_ops
->set_policy(vma
, new);
249 static struct mempolicy
*shm_get_policy(struct vm_area_struct
*vma
,
252 struct file
*file
= vma
->vm_file
;
253 struct shm_file_data
*sfd
= shm_file_data(file
);
254 struct mempolicy
*pol
= NULL
;
256 if (sfd
->vm_ops
->get_policy
)
257 pol
= sfd
->vm_ops
->get_policy(vma
, addr
);
258 else if (vma
->vm_policy
)
259 pol
= vma
->vm_policy
;
261 pol
= current
->mempolicy
;
266 static int shm_mmap(struct file
* file
, struct vm_area_struct
* vma
)
268 struct shm_file_data
*sfd
= shm_file_data(file
);
271 ret
= sfd
->file
->f_op
->mmap(sfd
->file
, vma
);
274 sfd
->vm_ops
= vma
->vm_ops
;
276 BUG_ON(!sfd
->vm_ops
->fault
);
278 vma
->vm_ops
= &shm_vm_ops
;
284 static int shm_release(struct inode
*ino
, struct file
*file
)
286 struct shm_file_data
*sfd
= shm_file_data(file
);
289 shm_file_data(file
) = NULL
;
294 static int shm_fsync(struct file
*file
, struct dentry
*dentry
, int datasync
)
296 int (*fsync
) (struct file
*, struct dentry
*, int datasync
);
297 struct shm_file_data
*sfd
= shm_file_data(file
);
300 fsync
= sfd
->file
->f_op
->fsync
;
302 ret
= fsync(sfd
->file
, sfd
->file
->f_path
.dentry
, datasync
);
306 static unsigned long shm_get_unmapped_area(struct file
*file
,
307 unsigned long addr
, unsigned long len
, unsigned long pgoff
,
310 struct shm_file_data
*sfd
= shm_file_data(file
);
311 return get_unmapped_area(sfd
->file
, addr
, len
, pgoff
, flags
);
314 int is_file_shm_hugepages(struct file
*file
)
318 if (file
->f_op
== &shm_file_operations
) {
319 struct shm_file_data
*sfd
;
320 sfd
= shm_file_data(file
);
321 ret
= is_file_hugepages(sfd
->file
);
326 static const struct file_operations shm_file_operations
= {
329 .release
= shm_release
,
330 .get_unmapped_area
= shm_get_unmapped_area
,
333 static struct vm_operations_struct shm_vm_ops
= {
334 .open
= shm_open
, /* callback for a new vm-area open */
335 .close
= shm_close
, /* callback for when the vm-area is released */
337 #if defined(CONFIG_NUMA)
338 .set_policy
= shm_set_policy
,
339 .get_policy
= shm_get_policy
,
343 static int newseg(struct ipc_namespace
*ns
, struct ipc_params
*params
)
345 key_t key
= params
->key
;
346 int shmflg
= params
->flg
;
347 size_t size
= params
->u
.size
;
349 struct shmid_kernel
*shp
;
350 int numpages
= (size
+ PAGE_SIZE
-1) >> PAGE_SHIFT
;
355 if (size
< SHMMIN
|| size
> ns
->shm_ctlmax
)
358 if (ns
->shm_tot
+ numpages
> ns
->shm_ctlall
)
361 shp
= ipc_rcu_alloc(sizeof(*shp
));
365 shp
->shm_perm
.key
= key
;
366 shp
->shm_perm
.mode
= (shmflg
& S_IRWXUGO
);
367 shp
->mlock_user
= NULL
;
369 shp
->shm_perm
.security
= NULL
;
370 error
= security_shm_alloc(shp
);
376 sprintf (name
, "SYSV%08x", key
);
377 if (shmflg
& SHM_HUGETLB
) {
378 /* hugetlb_file_setup takes care of mlock user accounting */
379 file
= hugetlb_file_setup(name
, size
);
380 shp
->mlock_user
= current
->user
;
382 int acctflag
= VM_ACCOUNT
;
384 * Do not allow no accounting for OVERCOMMIT_NEVER, even
387 if ((shmflg
& SHM_NORESERVE
) &&
388 sysctl_overcommit_memory
!= OVERCOMMIT_NEVER
)
390 file
= shmem_file_setup(name
, size
, acctflag
);
392 error
= PTR_ERR(file
);
397 id
= shm_addid(ns
, shp
);
401 shp
->shm_cprid
= task_tgid_vnr(current
);
403 shp
->shm_atim
= shp
->shm_dtim
= 0;
404 shp
->shm_ctim
= get_seconds();
405 shp
->shm_segsz
= size
;
407 shp
->shm_perm
.id
= shm_buildid(ns
, id
, shp
->shm_perm
.seq
);
408 shp
->shm_file
= file
;
410 * shmid gets reported as "inode#" in /proc/pid/maps.
411 * proc-ps tools use this. Changing this will break them.
413 file
->f_dentry
->d_inode
->i_ino
= shp
->shm_perm
.id
;
415 ns
->shm_tot
+= numpages
;
416 error
= shp
->shm_perm
.id
;
423 security_shm_free(shp
);
428 static inline int shm_security(void *shp
, int shmflg
)
430 return security_shm_associate((struct shmid_kernel
*) shp
, shmflg
);
433 static inline int shm_more_checks(void *shp
, struct ipc_params
*params
)
435 if (((struct shmid_kernel
*)shp
)->shm_segsz
< params
->u
.size
)
441 asmlinkage
long sys_shmget (key_t key
, size_t size
, int shmflg
)
443 struct ipc_namespace
*ns
;
444 struct ipc_ops shm_ops
;
445 struct ipc_params shm_params
;
447 ns
= current
->nsproxy
->ipc_ns
;
449 shm_ops
.getnew
= newseg
;
450 shm_ops
.associate
= shm_security
;
451 shm_ops
.more_checks
= shm_more_checks
;
453 shm_params
.key
= key
;
454 shm_params
.flg
= shmflg
;
455 shm_params
.u
.size
= size
;
457 return ipcget(ns
, &shm_ids(ns
), &shm_ops
, &shm_params
);
460 static inline unsigned long copy_shmid_to_user(void __user
*buf
, struct shmid64_ds
*in
, int version
)
464 return copy_to_user(buf
, in
, sizeof(*in
));
469 ipc64_perm_to_ipc_perm(&in
->shm_perm
, &out
.shm_perm
);
470 out
.shm_segsz
= in
->shm_segsz
;
471 out
.shm_atime
= in
->shm_atime
;
472 out
.shm_dtime
= in
->shm_dtime
;
473 out
.shm_ctime
= in
->shm_ctime
;
474 out
.shm_cpid
= in
->shm_cpid
;
475 out
.shm_lpid
= in
->shm_lpid
;
476 out
.shm_nattch
= in
->shm_nattch
;
478 return copy_to_user(buf
, &out
, sizeof(out
));
491 static inline unsigned long copy_shmid_from_user(struct shm_setbuf
*out
, void __user
*buf
, int version
)
496 struct shmid64_ds tbuf
;
498 if (copy_from_user(&tbuf
, buf
, sizeof(tbuf
)))
501 out
->uid
= tbuf
.shm_perm
.uid
;
502 out
->gid
= tbuf
.shm_perm
.gid
;
503 out
->mode
= tbuf
.shm_perm
.mode
;
509 struct shmid_ds tbuf_old
;
511 if (copy_from_user(&tbuf_old
, buf
, sizeof(tbuf_old
)))
514 out
->uid
= tbuf_old
.shm_perm
.uid
;
515 out
->gid
= tbuf_old
.shm_perm
.gid
;
516 out
->mode
= tbuf_old
.shm_perm
.mode
;
525 static inline unsigned long copy_shminfo_to_user(void __user
*buf
, struct shminfo64
*in
, int version
)
529 return copy_to_user(buf
, in
, sizeof(*in
));
534 if(in
->shmmax
> INT_MAX
)
535 out
.shmmax
= INT_MAX
;
537 out
.shmmax
= (int)in
->shmmax
;
539 out
.shmmin
= in
->shmmin
;
540 out
.shmmni
= in
->shmmni
;
541 out
.shmseg
= in
->shmseg
;
542 out
.shmall
= in
->shmall
;
544 return copy_to_user(buf
, &out
, sizeof(out
));
551 static void shm_get_stat(struct ipc_namespace
*ns
, unsigned long *rss
,
560 in_use
= shm_ids(ns
).in_use
;
562 for (total
= 0, next_id
= 0; total
< in_use
; next_id
++) {
563 struct shmid_kernel
*shp
;
566 shp
= shm_get(ns
, next_id
);
570 inode
= shp
->shm_file
->f_path
.dentry
->d_inode
;
572 if (is_file_hugepages(shp
->shm_file
)) {
573 struct address_space
*mapping
= inode
->i_mapping
;
574 *rss
+= (HPAGE_SIZE
/PAGE_SIZE
)*mapping
->nrpages
;
576 struct shmem_inode_info
*info
= SHMEM_I(inode
);
577 spin_lock(&info
->lock
);
578 *rss
+= inode
->i_mapping
->nrpages
;
579 *swp
+= info
->swapped
;
580 spin_unlock(&info
->lock
);
587 asmlinkage
long sys_shmctl (int shmid
, int cmd
, struct shmid_ds __user
*buf
)
589 struct shm_setbuf setbuf
;
590 struct shmid_kernel
*shp
;
592 struct ipc_namespace
*ns
;
594 if (cmd
< 0 || shmid
< 0) {
599 version
= ipc_parse_version(&cmd
);
600 ns
= current
->nsproxy
->ipc_ns
;
602 switch (cmd
) { /* replace with proc interface ? */
605 struct shminfo64 shminfo
;
607 err
= security_shm_shmctl(NULL
, cmd
);
611 memset(&shminfo
,0,sizeof(shminfo
));
612 shminfo
.shmmni
= shminfo
.shmseg
= ns
->shm_ctlmni
;
613 shminfo
.shmmax
= ns
->shm_ctlmax
;
614 shminfo
.shmall
= ns
->shm_ctlall
;
616 shminfo
.shmmin
= SHMMIN
;
617 if(copy_shminfo_to_user (buf
, &shminfo
, version
))
619 /* reading a integer is always atomic */
620 err
= ipc_get_maxid(&shm_ids(ns
));
627 struct shm_info shm_info
;
629 err
= security_shm_shmctl(NULL
, cmd
);
633 memset(&shm_info
,0,sizeof(shm_info
));
634 mutex_lock(&shm_ids(ns
).mutex
);
635 shm_info
.used_ids
= shm_ids(ns
).in_use
;
636 shm_get_stat (ns
, &shm_info
.shm_rss
, &shm_info
.shm_swp
);
637 shm_info
.shm_tot
= ns
->shm_tot
;
638 shm_info
.swap_attempts
= 0;
639 shm_info
.swap_successes
= 0;
640 err
= ipc_get_maxid(&shm_ids(ns
));
641 mutex_unlock(&shm_ids(ns
).mutex
);
642 if(copy_to_user (buf
, &shm_info
, sizeof(shm_info
))) {
647 err
= err
< 0 ? 0 : err
;
653 struct shmid64_ds tbuf
;
655 memset(&tbuf
, 0, sizeof(tbuf
));
656 shp
= shm_lock(ns
, shmid
);
660 } else if (cmd
== SHM_STAT
) {
661 result
= shp
->shm_perm
.id
;
663 err
= shm_checkid(ns
, shp
,shmid
);
669 if (ipcperms (&shp
->shm_perm
, S_IRUGO
))
671 err
= security_shm_shmctl(shp
, cmd
);
674 kernel_to_ipc64_perm(&shp
->shm_perm
, &tbuf
.shm_perm
);
675 tbuf
.shm_segsz
= shp
->shm_segsz
;
676 tbuf
.shm_atime
= shp
->shm_atim
;
677 tbuf
.shm_dtime
= shp
->shm_dtim
;
678 tbuf
.shm_ctime
= shp
->shm_ctim
;
679 tbuf
.shm_cpid
= shp
->shm_cprid
;
680 tbuf
.shm_lpid
= shp
->shm_lprid
;
681 tbuf
.shm_nattch
= shp
->shm_nattch
;
683 if(copy_shmid_to_user (buf
, &tbuf
, version
))
692 shp
= shm_lock(ns
, shmid
);
697 err
= shm_checkid(ns
, shp
,shmid
);
701 err
= audit_ipc_obj(&(shp
->shm_perm
));
705 if (!capable(CAP_IPC_LOCK
)) {
707 if (current
->euid
!= shp
->shm_perm
.uid
&&
708 current
->euid
!= shp
->shm_perm
.cuid
)
710 if (cmd
== SHM_LOCK
&&
711 !current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
)
715 err
= security_shm_shmctl(shp
, cmd
);
720 struct user_struct
* user
= current
->user
;
721 if (!is_file_hugepages(shp
->shm_file
)) {
722 err
= shmem_lock(shp
->shm_file
, 1, user
);
723 if (!err
&& !(shp
->shm_perm
.mode
& SHM_LOCKED
)){
724 shp
->shm_perm
.mode
|= SHM_LOCKED
;
725 shp
->mlock_user
= user
;
728 } else if (!is_file_hugepages(shp
->shm_file
)) {
729 shmem_lock(shp
->shm_file
, 0, shp
->mlock_user
);
730 shp
->shm_perm
.mode
&= ~SHM_LOCKED
;
731 shp
->mlock_user
= NULL
;
739 * We cannot simply remove the file. The SVID states
740 * that the block remains until the last person
741 * detaches from it, then is deleted. A shmat() on
742 * an RMID segment is legal in older Linux and if
743 * we change it apps break...
745 * Instead we set a destroyed flag, and then blow
746 * the name away when the usage hits zero.
748 mutex_lock(&shm_ids(ns
).mutex
);
749 shp
= shm_lock(ns
, shmid
);
753 err
= shm_checkid(ns
, shp
, shmid
);
757 err
= audit_ipc_obj(&(shp
->shm_perm
));
761 if (current
->euid
!= shp
->shm_perm
.uid
&&
762 current
->euid
!= shp
->shm_perm
.cuid
&&
763 !capable(CAP_SYS_ADMIN
)) {
768 err
= security_shm_shmctl(shp
, cmd
);
772 do_shm_rmid(ns
, shp
);
773 mutex_unlock(&shm_ids(ns
).mutex
);
779 if (copy_shmid_from_user (&setbuf
, buf
, version
)) {
783 mutex_lock(&shm_ids(ns
).mutex
);
784 shp
= shm_lock(ns
, shmid
);
788 err
= shm_checkid(ns
, shp
,shmid
);
791 err
= audit_ipc_obj(&(shp
->shm_perm
));
794 err
= audit_ipc_set_perm(0, setbuf
.uid
, setbuf
.gid
, setbuf
.mode
);
798 if (current
->euid
!= shp
->shm_perm
.uid
&&
799 current
->euid
!= shp
->shm_perm
.cuid
&&
800 !capable(CAP_SYS_ADMIN
)) {
804 err
= security_shm_shmctl(shp
, cmd
);
808 shp
->shm_perm
.uid
= setbuf
.uid
;
809 shp
->shm_perm
.gid
= setbuf
.gid
;
810 shp
->shm_perm
.mode
= (shp
->shm_perm
.mode
& ~S_IRWXUGO
)
811 | (setbuf
.mode
& S_IRWXUGO
);
812 shp
->shm_ctim
= get_seconds();
825 mutex_unlock(&shm_ids(ns
).mutex
);
834 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
836 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
837 * "raddr" thing points to kernel space, and there has to be a wrapper around
840 long do_shmat(int shmid
, char __user
*shmaddr
, int shmflg
, ulong
*raddr
)
842 struct shmid_kernel
*shp
;
850 unsigned long user_addr
;
851 struct ipc_namespace
*ns
;
852 struct shm_file_data
*sfd
;
859 else if ((addr
= (ulong
)shmaddr
)) {
860 if (addr
& (SHMLBA
-1)) {
861 if (shmflg
& SHM_RND
)
862 addr
&= ~(SHMLBA
-1); /* round down */
864 #ifndef __ARCH_FORCE_SHMLBA
865 if (addr
& ~PAGE_MASK
)
869 flags
= MAP_SHARED
| MAP_FIXED
;
871 if ((shmflg
& SHM_REMAP
))
877 if (shmflg
& SHM_RDONLY
) {
882 prot
= PROT_READ
| PROT_WRITE
;
883 acc_mode
= S_IRUGO
| S_IWUGO
;
884 f_mode
= FMODE_READ
| FMODE_WRITE
;
886 if (shmflg
& SHM_EXEC
) {
892 * We cannot rely on the fs check since SYSV IPC does have an
893 * additional creator id...
895 ns
= current
->nsproxy
->ipc_ns
;
896 shp
= shm_lock(ns
, shmid
);
900 err
= shm_checkid(ns
, shp
,shmid
);
905 if (ipcperms(&shp
->shm_perm
, acc_mode
))
908 err
= security_shm_shmat(shp
, shmaddr
, shmflg
);
912 path
.dentry
= dget(shp
->shm_file
->f_path
.dentry
);
913 path
.mnt
= shp
->shm_file
->f_path
.mnt
;
915 size
= i_size_read(path
.dentry
->d_inode
);
919 sfd
= kzalloc(sizeof(*sfd
), GFP_KERNEL
);
925 file
= alloc_file(path
.mnt
, path
.dentry
, f_mode
, &shm_file_operations
);
929 file
->private_data
= sfd
;
930 file
->f_mapping
= shp
->shm_file
->f_mapping
;
931 sfd
->id
= shp
->shm_perm
.id
;
932 sfd
->ns
= get_ipc_ns(ns
);
933 sfd
->file
= shp
->shm_file
;
936 down_write(¤t
->mm
->mmap_sem
);
937 if (addr
&& !(shmflg
& SHM_REMAP
)) {
939 if (find_vma_intersection(current
->mm
, addr
, addr
+ size
))
942 * If shm segment goes below stack, make sure there is some
943 * space left for the stack to grow (at least 4 pages).
945 if (addr
< current
->mm
->start_stack
&&
946 addr
> current
->mm
->start_stack
- size
- PAGE_SIZE
* 5)
950 user_addr
= do_mmap (file
, addr
, size
, prot
, flags
, 0);
953 if (IS_ERR_VALUE(user_addr
))
954 err
= (long)user_addr
;
956 up_write(¤t
->mm
->mmap_sem
);
961 mutex_lock(&shm_ids(ns
).mutex
);
962 shp
= shm_lock(ns
, shmid
);
965 if(shp
->shm_nattch
== 0 &&
966 shp
->shm_perm
.mode
& SHM_DEST
)
967 shm_destroy(ns
, shp
);
970 mutex_unlock(&shm_ids(ns
).mutex
);
986 asmlinkage
long sys_shmat(int shmid
, char __user
*shmaddr
, int shmflg
)
991 err
= do_shmat(shmid
, shmaddr
, shmflg
, &ret
);
994 force_successful_syscall_return();
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
;
1008 int retval
= -EINVAL
;
1010 if (addr
& ~PAGE_MASK
)
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
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
);
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.
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
);
1081 up_write(&mm
->mmap_sem
);
1085 #ifdef CONFIG_PROC_FS
1086 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
)
1088 struct shmid_kernel
*shp
= it
;
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
;
1097 format
= BIG_STRING
;
1098 return seq_printf(s
, format
,