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_buildid(ns, id, seq) \
67 ipc_buildid(&shm_ids(ns), id, seq)
69 static int newseg(struct ipc_namespace
*, struct ipc_params
*);
70 static void shm_open(struct vm_area_struct
*vma
);
71 static void shm_close(struct vm_area_struct
*vma
);
72 static void shm_destroy (struct ipc_namespace
*ns
, struct shmid_kernel
*shp
);
74 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
);
77 static void __shm_init_ns(struct ipc_namespace
*ns
, struct ipc_ids
*ids
)
79 ns
->ids
[IPC_SHM_IDS
] = ids
;
80 ns
->shm_ctlmax
= SHMMAX
;
81 ns
->shm_ctlall
= SHMALL
;
82 ns
->shm_ctlmni
= SHMMNI
;
87 static void do_shm_rmid(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
90 shp
->shm_perm
.mode
|= SHM_DEST
;
91 /* Do not find it any more */
92 shp
->shm_perm
.key
= IPC_PRIVATE
;
98 int shm_init_ns(struct ipc_namespace
*ns
)
102 ids
= kmalloc(sizeof(struct ipc_ids
), GFP_KERNEL
);
106 __shm_init_ns(ns
, ids
);
110 void shm_exit_ns(struct ipc_namespace
*ns
)
112 struct shmid_kernel
*shp
;
116 mutex_lock(&shm_ids(ns
).mutex
);
118 in_use
= shm_ids(ns
).in_use
;
120 for (total
= 0, next_id
= 0; total
< in_use
; next_id
++) {
121 shp
= idr_find(&shm_ids(ns
).ipcs_idr
, next_id
);
124 ipc_lock_by_ptr(&shp
->shm_perm
);
125 do_shm_rmid(ns
, shp
);
128 mutex_unlock(&shm_ids(ns
).mutex
);
130 kfree(ns
->ids
[IPC_SHM_IDS
]);
131 ns
->ids
[IPC_SHM_IDS
] = NULL
;
134 void __init
shm_init (void)
136 __shm_init_ns(&init_ipc_ns
, &init_shm_ids
);
137 ipc_init_proc_interface("sysvipc/shm",
138 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
139 IPC_SHM_IDS
, sysvipc_shm_proc_show
);
142 static inline int shm_checkid(struct ipc_namespace
*ns
,
143 struct shmid_kernel
*s
, int id
)
145 if (ipc_checkid(&shm_ids(ns
), &s
->shm_perm
, id
))
150 static inline void shm_rmid(struct ipc_namespace
*ns
, struct shmid_kernel
*s
)
152 ipc_rmid(&shm_ids(ns
), &s
->shm_perm
);
155 static inline int shm_addid(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
157 return ipc_addid(&shm_ids(ns
), &shp
->shm_perm
, ns
->shm_ctlmni
);
162 /* This is called by fork, once for every shm attach. */
163 static void shm_open(struct vm_area_struct
*vma
)
165 struct file
*file
= vma
->vm_file
;
166 struct shm_file_data
*sfd
= shm_file_data(file
);
167 struct shmid_kernel
*shp
;
169 shp
= shm_lock(sfd
->ns
, sfd
->id
);
171 shp
->shm_atim
= get_seconds();
172 shp
->shm_lprid
= task_tgid_vnr(current
);
178 * shm_destroy - free the struct shmid_kernel
180 * @shp: struct to free
182 * It has to be called with shp and shm_ids.mutex locked,
183 * but returns with shp unlocked and freed.
185 static void shm_destroy(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
187 ns
->shm_tot
-= (shp
->shm_segsz
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
190 if (!is_file_hugepages(shp
->shm_file
))
191 shmem_lock(shp
->shm_file
, 0, shp
->mlock_user
);
193 user_shm_unlock(shp
->shm_file
->f_path
.dentry
->d_inode
->i_size
,
195 fput (shp
->shm_file
);
196 security_shm_free(shp
);
201 * remove the attach descriptor vma.
202 * free memory for segment if it is marked destroyed.
203 * The descriptor has already been removed from the current->mm->mmap list
204 * and will later be kfree()d.
206 static void shm_close(struct vm_area_struct
*vma
)
208 struct file
* file
= vma
->vm_file
;
209 struct shm_file_data
*sfd
= shm_file_data(file
);
210 struct shmid_kernel
*shp
;
211 struct ipc_namespace
*ns
= sfd
->ns
;
213 mutex_lock(&shm_ids(ns
).mutex
);
214 /* remove from the list of attaches of the shm segment */
215 shp
= shm_lock(ns
, sfd
->id
);
217 shp
->shm_lprid
= task_tgid_vnr(current
);
218 shp
->shm_dtim
= get_seconds();
220 if(shp
->shm_nattch
== 0 &&
221 shp
->shm_perm
.mode
& SHM_DEST
)
222 shm_destroy(ns
, shp
);
225 mutex_unlock(&shm_ids(ns
).mutex
);
228 static int shm_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
230 struct file
*file
= vma
->vm_file
;
231 struct shm_file_data
*sfd
= shm_file_data(file
);
233 return sfd
->vm_ops
->fault(vma
, vmf
);
237 static int shm_set_policy(struct vm_area_struct
*vma
, struct mempolicy
*new)
239 struct file
*file
= vma
->vm_file
;
240 struct shm_file_data
*sfd
= shm_file_data(file
);
242 if (sfd
->vm_ops
->set_policy
)
243 err
= sfd
->vm_ops
->set_policy(vma
, new);
247 static struct mempolicy
*shm_get_policy(struct vm_area_struct
*vma
,
250 struct file
*file
= vma
->vm_file
;
251 struct shm_file_data
*sfd
= shm_file_data(file
);
252 struct mempolicy
*pol
= NULL
;
254 if (sfd
->vm_ops
->get_policy
)
255 pol
= sfd
->vm_ops
->get_policy(vma
, addr
);
256 else if (vma
->vm_policy
)
257 pol
= vma
->vm_policy
;
259 pol
= current
->mempolicy
;
264 static int shm_mmap(struct file
* file
, struct vm_area_struct
* vma
)
266 struct shm_file_data
*sfd
= shm_file_data(file
);
269 ret
= sfd
->file
->f_op
->mmap(sfd
->file
, vma
);
272 sfd
->vm_ops
= vma
->vm_ops
;
274 BUG_ON(!sfd
->vm_ops
->fault
);
276 vma
->vm_ops
= &shm_vm_ops
;
282 static int shm_release(struct inode
*ino
, struct file
*file
)
284 struct shm_file_data
*sfd
= shm_file_data(file
);
287 shm_file_data(file
) = NULL
;
292 static int shm_fsync(struct file
*file
, struct dentry
*dentry
, int datasync
)
294 int (*fsync
) (struct file
*, struct dentry
*, int datasync
);
295 struct shm_file_data
*sfd
= shm_file_data(file
);
298 fsync
= sfd
->file
->f_op
->fsync
;
300 ret
= fsync(sfd
->file
, sfd
->file
->f_path
.dentry
, datasync
);
304 static unsigned long shm_get_unmapped_area(struct file
*file
,
305 unsigned long addr
, unsigned long len
, unsigned long pgoff
,
308 struct shm_file_data
*sfd
= shm_file_data(file
);
309 return get_unmapped_area(sfd
->file
, addr
, len
, pgoff
, flags
);
312 int is_file_shm_hugepages(struct file
*file
)
316 if (file
->f_op
== &shm_file_operations
) {
317 struct shm_file_data
*sfd
;
318 sfd
= shm_file_data(file
);
319 ret
= is_file_hugepages(sfd
->file
);
324 static const struct file_operations shm_file_operations
= {
327 .release
= shm_release
,
328 .get_unmapped_area
= shm_get_unmapped_area
,
331 static struct vm_operations_struct shm_vm_ops
= {
332 .open
= shm_open
, /* callback for a new vm-area open */
333 .close
= shm_close
, /* callback for when the vm-area is released */
335 #if defined(CONFIG_NUMA)
336 .set_policy
= shm_set_policy
,
337 .get_policy
= shm_get_policy
,
341 static int newseg(struct ipc_namespace
*ns
, struct ipc_params
*params
)
343 key_t key
= params
->key
;
344 int shmflg
= params
->flg
;
345 size_t size
= params
->u
.size
;
347 struct shmid_kernel
*shp
;
348 int numpages
= (size
+ PAGE_SIZE
-1) >> PAGE_SHIFT
;
353 if (size
< SHMMIN
|| size
> ns
->shm_ctlmax
)
356 if (ns
->shm_tot
+ numpages
> ns
->shm_ctlall
)
359 shp
= ipc_rcu_alloc(sizeof(*shp
));
363 shp
->shm_perm
.key
= key
;
364 shp
->shm_perm
.mode
= (shmflg
& S_IRWXUGO
);
365 shp
->mlock_user
= NULL
;
367 shp
->shm_perm
.security
= NULL
;
368 error
= security_shm_alloc(shp
);
374 sprintf (name
, "SYSV%08x", key
);
375 if (shmflg
& SHM_HUGETLB
) {
376 /* hugetlb_file_setup takes care of mlock user accounting */
377 file
= hugetlb_file_setup(name
, size
);
378 shp
->mlock_user
= current
->user
;
380 int acctflag
= VM_ACCOUNT
;
382 * Do not allow no accounting for OVERCOMMIT_NEVER, even
385 if ((shmflg
& SHM_NORESERVE
) &&
386 sysctl_overcommit_memory
!= OVERCOMMIT_NEVER
)
388 file
= shmem_file_setup(name
, size
, acctflag
);
390 error
= PTR_ERR(file
);
395 id
= shm_addid(ns
, shp
);
399 shp
->shm_cprid
= task_tgid_vnr(current
);
401 shp
->shm_atim
= shp
->shm_dtim
= 0;
402 shp
->shm_ctim
= get_seconds();
403 shp
->shm_segsz
= size
;
405 shp
->shm_perm
.id
= shm_buildid(ns
, id
, shp
->shm_perm
.seq
);
406 shp
->shm_file
= file
;
408 * shmid gets reported as "inode#" in /proc/pid/maps.
409 * proc-ps tools use this. Changing this will break them.
411 file
->f_dentry
->d_inode
->i_ino
= shp
->shm_perm
.id
;
413 ns
->shm_tot
+= numpages
;
414 error
= shp
->shm_perm
.id
;
421 security_shm_free(shp
);
426 static inline int shm_security(void *shp
, int shmflg
)
428 return security_shm_associate((struct shmid_kernel
*) shp
, shmflg
);
431 static inline int shm_more_checks(void *shp
, struct ipc_params
*params
)
433 if (((struct shmid_kernel
*)shp
)->shm_segsz
< params
->u
.size
)
439 asmlinkage
long sys_shmget (key_t key
, size_t size
, int shmflg
)
441 struct ipc_namespace
*ns
;
442 struct ipc_ops shm_ops
;
443 struct ipc_params shm_params
;
445 ns
= current
->nsproxy
->ipc_ns
;
447 shm_ops
.getnew
= newseg
;
448 shm_ops
.associate
= shm_security
;
449 shm_ops
.more_checks
= shm_more_checks
;
451 shm_params
.key
= key
;
452 shm_params
.flg
= shmflg
;
453 shm_params
.u
.size
= size
;
455 return ipcget(ns
, &shm_ids(ns
), &shm_ops
, &shm_params
);
458 static inline unsigned long copy_shmid_to_user(void __user
*buf
, struct shmid64_ds
*in
, int version
)
462 return copy_to_user(buf
, in
, sizeof(*in
));
467 ipc64_perm_to_ipc_perm(&in
->shm_perm
, &out
.shm_perm
);
468 out
.shm_segsz
= in
->shm_segsz
;
469 out
.shm_atime
= in
->shm_atime
;
470 out
.shm_dtime
= in
->shm_dtime
;
471 out
.shm_ctime
= in
->shm_ctime
;
472 out
.shm_cpid
= in
->shm_cpid
;
473 out
.shm_lpid
= in
->shm_lpid
;
474 out
.shm_nattch
= in
->shm_nattch
;
476 return copy_to_user(buf
, &out
, sizeof(out
));
489 static inline unsigned long copy_shmid_from_user(struct shm_setbuf
*out
, void __user
*buf
, int version
)
494 struct shmid64_ds tbuf
;
496 if (copy_from_user(&tbuf
, buf
, sizeof(tbuf
)))
499 out
->uid
= tbuf
.shm_perm
.uid
;
500 out
->gid
= tbuf
.shm_perm
.gid
;
501 out
->mode
= tbuf
.shm_perm
.mode
;
507 struct shmid_ds tbuf_old
;
509 if (copy_from_user(&tbuf_old
, buf
, sizeof(tbuf_old
)))
512 out
->uid
= tbuf_old
.shm_perm
.uid
;
513 out
->gid
= tbuf_old
.shm_perm
.gid
;
514 out
->mode
= tbuf_old
.shm_perm
.mode
;
523 static inline unsigned long copy_shminfo_to_user(void __user
*buf
, struct shminfo64
*in
, int version
)
527 return copy_to_user(buf
, in
, sizeof(*in
));
532 if(in
->shmmax
> INT_MAX
)
533 out
.shmmax
= INT_MAX
;
535 out
.shmmax
= (int)in
->shmmax
;
537 out
.shmmin
= in
->shmmin
;
538 out
.shmmni
= in
->shmmni
;
539 out
.shmseg
= in
->shmseg
;
540 out
.shmall
= in
->shmall
;
542 return copy_to_user(buf
, &out
, sizeof(out
));
549 static void shm_get_stat(struct ipc_namespace
*ns
, unsigned long *rss
,
558 in_use
= shm_ids(ns
).in_use
;
560 for (total
= 0, next_id
= 0; total
< in_use
; next_id
++) {
561 struct shmid_kernel
*shp
;
565 * idr_find() is called via shm_get(), so with shm_ids.mutex
566 * locked. Since ipc_addid() is also called with
567 * shm_ids.mutex down, there is no need to add read barriers
568 * here to gurantee the writes in ipc_addid() are seen in
569 * order here (for Alpha).
570 * However idr_find() itself does not necessary require
571 * ipc_ids.mutex down. So if idr_find() is used by other
572 * places without ipc_ids.mutex down, then it needs read
573 * read memory barriers as ipc_lock() does.
576 shp
= idr_find(&shm_ids(ns
).ipcs_idr
, next_id
);
580 inode
= shp
->shm_file
->f_path
.dentry
->d_inode
;
582 if (is_file_hugepages(shp
->shm_file
)) {
583 struct address_space
*mapping
= inode
->i_mapping
;
584 *rss
+= (HPAGE_SIZE
/PAGE_SIZE
)*mapping
->nrpages
;
586 struct shmem_inode_info
*info
= SHMEM_I(inode
);
587 spin_lock(&info
->lock
);
588 *rss
+= inode
->i_mapping
->nrpages
;
589 *swp
+= info
->swapped
;
590 spin_unlock(&info
->lock
);
597 asmlinkage
long sys_shmctl (int shmid
, int cmd
, struct shmid_ds __user
*buf
)
599 struct shm_setbuf setbuf
;
600 struct shmid_kernel
*shp
;
602 struct ipc_namespace
*ns
;
604 if (cmd
< 0 || shmid
< 0) {
609 version
= ipc_parse_version(&cmd
);
610 ns
= current
->nsproxy
->ipc_ns
;
612 switch (cmd
) { /* replace with proc interface ? */
615 struct shminfo64 shminfo
;
617 err
= security_shm_shmctl(NULL
, cmd
);
621 memset(&shminfo
,0,sizeof(shminfo
));
622 shminfo
.shmmni
= shminfo
.shmseg
= ns
->shm_ctlmni
;
623 shminfo
.shmmax
= ns
->shm_ctlmax
;
624 shminfo
.shmall
= ns
->shm_ctlall
;
626 shminfo
.shmmin
= SHMMIN
;
627 if(copy_shminfo_to_user (buf
, &shminfo
, version
))
629 /* reading a integer is always atomic */
630 err
= ipc_get_maxid(&shm_ids(ns
));
637 struct shm_info shm_info
;
639 err
= security_shm_shmctl(NULL
, cmd
);
643 memset(&shm_info
,0,sizeof(shm_info
));
644 mutex_lock(&shm_ids(ns
).mutex
);
645 shm_info
.used_ids
= shm_ids(ns
).in_use
;
646 shm_get_stat (ns
, &shm_info
.shm_rss
, &shm_info
.shm_swp
);
647 shm_info
.shm_tot
= ns
->shm_tot
;
648 shm_info
.swap_attempts
= 0;
649 shm_info
.swap_successes
= 0;
650 err
= ipc_get_maxid(&shm_ids(ns
));
651 mutex_unlock(&shm_ids(ns
).mutex
);
652 if(copy_to_user (buf
, &shm_info
, sizeof(shm_info
))) {
657 err
= err
< 0 ? 0 : err
;
663 struct shmid64_ds tbuf
;
665 memset(&tbuf
, 0, sizeof(tbuf
));
666 shp
= shm_lock(ns
, shmid
);
670 } else if (cmd
== SHM_STAT
) {
671 result
= shp
->shm_perm
.id
;
673 err
= shm_checkid(ns
, shp
,shmid
);
679 if (ipcperms (&shp
->shm_perm
, S_IRUGO
))
681 err
= security_shm_shmctl(shp
, cmd
);
684 kernel_to_ipc64_perm(&shp
->shm_perm
, &tbuf
.shm_perm
);
685 tbuf
.shm_segsz
= shp
->shm_segsz
;
686 tbuf
.shm_atime
= shp
->shm_atim
;
687 tbuf
.shm_dtime
= shp
->shm_dtim
;
688 tbuf
.shm_ctime
= shp
->shm_ctim
;
689 tbuf
.shm_cpid
= shp
->shm_cprid
;
690 tbuf
.shm_lpid
= shp
->shm_lprid
;
691 tbuf
.shm_nattch
= shp
->shm_nattch
;
693 if(copy_shmid_to_user (buf
, &tbuf
, version
))
702 shp
= shm_lock(ns
, shmid
);
707 err
= shm_checkid(ns
, shp
,shmid
);
711 err
= audit_ipc_obj(&(shp
->shm_perm
));
715 if (!capable(CAP_IPC_LOCK
)) {
717 if (current
->euid
!= shp
->shm_perm
.uid
&&
718 current
->euid
!= shp
->shm_perm
.cuid
)
720 if (cmd
== SHM_LOCK
&&
721 !current
->signal
->rlim
[RLIMIT_MEMLOCK
].rlim_cur
)
725 err
= security_shm_shmctl(shp
, cmd
);
730 struct user_struct
* user
= current
->user
;
731 if (!is_file_hugepages(shp
->shm_file
)) {
732 err
= shmem_lock(shp
->shm_file
, 1, user
);
733 if (!err
&& !(shp
->shm_perm
.mode
& SHM_LOCKED
)){
734 shp
->shm_perm
.mode
|= SHM_LOCKED
;
735 shp
->mlock_user
= user
;
738 } else if (!is_file_hugepages(shp
->shm_file
)) {
739 shmem_lock(shp
->shm_file
, 0, shp
->mlock_user
);
740 shp
->shm_perm
.mode
&= ~SHM_LOCKED
;
741 shp
->mlock_user
= NULL
;
749 * We cannot simply remove the file. The SVID states
750 * that the block remains until the last person
751 * detaches from it, then is deleted. A shmat() on
752 * an RMID segment is legal in older Linux and if
753 * we change it apps break...
755 * Instead we set a destroyed flag, and then blow
756 * the name away when the usage hits zero.
758 mutex_lock(&shm_ids(ns
).mutex
);
759 shp
= shm_lock(ns
, shmid
);
763 err
= shm_checkid(ns
, shp
, shmid
);
767 err
= audit_ipc_obj(&(shp
->shm_perm
));
771 if (current
->euid
!= shp
->shm_perm
.uid
&&
772 current
->euid
!= shp
->shm_perm
.cuid
&&
773 !capable(CAP_SYS_ADMIN
)) {
778 err
= security_shm_shmctl(shp
, cmd
);
782 do_shm_rmid(ns
, shp
);
783 mutex_unlock(&shm_ids(ns
).mutex
);
789 if (copy_shmid_from_user (&setbuf
, buf
, version
)) {
793 mutex_lock(&shm_ids(ns
).mutex
);
794 shp
= shm_lock(ns
, shmid
);
798 err
= shm_checkid(ns
, shp
,shmid
);
801 err
= audit_ipc_obj(&(shp
->shm_perm
));
804 err
= audit_ipc_set_perm(0, setbuf
.uid
, setbuf
.gid
, setbuf
.mode
);
808 if (current
->euid
!= shp
->shm_perm
.uid
&&
809 current
->euid
!= shp
->shm_perm
.cuid
&&
810 !capable(CAP_SYS_ADMIN
)) {
814 err
= security_shm_shmctl(shp
, cmd
);
818 shp
->shm_perm
.uid
= setbuf
.uid
;
819 shp
->shm_perm
.gid
= setbuf
.gid
;
820 shp
->shm_perm
.mode
= (shp
->shm_perm
.mode
& ~S_IRWXUGO
)
821 | (setbuf
.mode
& S_IRWXUGO
);
822 shp
->shm_ctim
= get_seconds();
835 mutex_unlock(&shm_ids(ns
).mutex
);
844 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
846 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
847 * "raddr" thing points to kernel space, and there has to be a wrapper around
850 long do_shmat(int shmid
, char __user
*shmaddr
, int shmflg
, ulong
*raddr
)
852 struct shmid_kernel
*shp
;
860 unsigned long user_addr
;
861 struct ipc_namespace
*ns
;
862 struct shm_file_data
*sfd
;
869 else if ((addr
= (ulong
)shmaddr
)) {
870 if (addr
& (SHMLBA
-1)) {
871 if (shmflg
& SHM_RND
)
872 addr
&= ~(SHMLBA
-1); /* round down */
874 #ifndef __ARCH_FORCE_SHMLBA
875 if (addr
& ~PAGE_MASK
)
879 flags
= MAP_SHARED
| MAP_FIXED
;
881 if ((shmflg
& SHM_REMAP
))
887 if (shmflg
& SHM_RDONLY
) {
892 prot
= PROT_READ
| PROT_WRITE
;
893 acc_mode
= S_IRUGO
| S_IWUGO
;
894 f_mode
= FMODE_READ
| FMODE_WRITE
;
896 if (shmflg
& SHM_EXEC
) {
902 * We cannot rely on the fs check since SYSV IPC does have an
903 * additional creator id...
905 ns
= current
->nsproxy
->ipc_ns
;
906 shp
= shm_lock(ns
, shmid
);
910 err
= shm_checkid(ns
, shp
,shmid
);
915 if (ipcperms(&shp
->shm_perm
, acc_mode
))
918 err
= security_shm_shmat(shp
, shmaddr
, shmflg
);
922 path
.dentry
= dget(shp
->shm_file
->f_path
.dentry
);
923 path
.mnt
= shp
->shm_file
->f_path
.mnt
;
925 size
= i_size_read(path
.dentry
->d_inode
);
929 sfd
= kzalloc(sizeof(*sfd
), GFP_KERNEL
);
935 file
= alloc_file(path
.mnt
, path
.dentry
, f_mode
, &shm_file_operations
);
939 file
->private_data
= sfd
;
940 file
->f_mapping
= shp
->shm_file
->f_mapping
;
941 sfd
->id
= shp
->shm_perm
.id
;
942 sfd
->ns
= get_ipc_ns(ns
);
943 sfd
->file
= shp
->shm_file
;
946 down_write(¤t
->mm
->mmap_sem
);
947 if (addr
&& !(shmflg
& SHM_REMAP
)) {
949 if (find_vma_intersection(current
->mm
, addr
, addr
+ size
))
952 * If shm segment goes below stack, make sure there is some
953 * space left for the stack to grow (at least 4 pages).
955 if (addr
< current
->mm
->start_stack
&&
956 addr
> current
->mm
->start_stack
- size
- PAGE_SIZE
* 5)
960 user_addr
= do_mmap (file
, addr
, size
, prot
, flags
, 0);
963 if (IS_ERR_VALUE(user_addr
))
964 err
= (long)user_addr
;
966 up_write(¤t
->mm
->mmap_sem
);
971 mutex_lock(&shm_ids(ns
).mutex
);
972 shp
= shm_lock(ns
, shmid
);
975 if(shp
->shm_nattch
== 0 &&
976 shp
->shm_perm
.mode
& SHM_DEST
)
977 shm_destroy(ns
, shp
);
980 mutex_unlock(&shm_ids(ns
).mutex
);
996 asmlinkage
long sys_shmat(int shmid
, char __user
*shmaddr
, int shmflg
)
1001 err
= do_shmat(shmid
, shmaddr
, shmflg
, &ret
);
1004 force_successful_syscall_return();
1009 * detach and kill segment if marked destroyed.
1010 * The work is done in shm_close.
1012 asmlinkage
long sys_shmdt(char __user
*shmaddr
)
1014 struct mm_struct
*mm
= current
->mm
;
1015 struct vm_area_struct
*vma
, *next
;
1016 unsigned long addr
= (unsigned long)shmaddr
;
1018 int retval
= -EINVAL
;
1020 if (addr
& ~PAGE_MASK
)
1023 down_write(&mm
->mmap_sem
);
1026 * This function tries to be smart and unmap shm segments that
1027 * were modified by partial mlock or munmap calls:
1028 * - It first determines the size of the shm segment that should be
1029 * unmapped: It searches for a vma that is backed by shm and that
1030 * started at address shmaddr. It records it's size and then unmaps
1032 * - Then it unmaps all shm vmas that started at shmaddr and that
1033 * are within the initially determined size.
1034 * Errors from do_munmap are ignored: the function only fails if
1035 * it's called with invalid parameters or if it's called to unmap
1036 * a part of a vma. Both calls in this function are for full vmas,
1037 * the parameters are directly copied from the vma itself and always
1038 * valid - therefore do_munmap cannot fail. (famous last words?)
1041 * If it had been mremap()'d, the starting address would not
1042 * match the usual checks anyway. So assume all vma's are
1043 * above the starting address given.
1045 vma
= find_vma(mm
, addr
);
1048 next
= vma
->vm_next
;
1051 * Check if the starting address would match, i.e. it's
1052 * a fragment created by mprotect() and/or munmap(), or it
1053 * otherwise it starts at this address with no hassles.
1055 if ((vma
->vm_ops
== &shm_vm_ops
) &&
1056 (vma
->vm_start
- addr
)/PAGE_SIZE
== vma
->vm_pgoff
) {
1059 size
= vma
->vm_file
->f_path
.dentry
->d_inode
->i_size
;
1060 do_munmap(mm
, vma
->vm_start
, vma
->vm_end
- vma
->vm_start
);
1062 * We discovered the size of the shm segment, so
1063 * break out of here and fall through to the next
1064 * loop that uses the size information to stop
1065 * searching for matching vma's.
1075 * We need look no further than the maximum address a fragment
1076 * could possibly have landed at. Also cast things to loff_t to
1077 * prevent overflows and make comparisions vs. equal-width types.
1079 size
= PAGE_ALIGN(size
);
1080 while (vma
&& (loff_t
)(vma
->vm_end
- addr
) <= size
) {
1081 next
= vma
->vm_next
;
1083 /* finding a matching vma now does not alter retval */
1084 if ((vma
->vm_ops
== &shm_vm_ops
) &&
1085 (vma
->vm_start
- addr
)/PAGE_SIZE
== vma
->vm_pgoff
)
1087 do_munmap(mm
, vma
->vm_start
, vma
->vm_end
- vma
->vm_start
);
1091 up_write(&mm
->mmap_sem
);
1095 #ifdef CONFIG_PROC_FS
1096 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
)
1098 struct shmid_kernel
*shp
= it
;
1101 #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1102 #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1104 if (sizeof(size_t) <= sizeof(int))
1105 format
= SMALL_STRING
;
1107 format
= BIG_STRING
;
1108 return seq_printf(s
, format
,