1 // SPDX-License-Identifier: GPL-2.0
4 * Copyright (C) 1992, 1993 Krishna Balasubramanian
5 * Many improvements/fixes by Bruno Haible.
6 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
7 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
9 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
10 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
11 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
12 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
13 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
14 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
15 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
17 * support for audit of ipc object properties and permission changes
18 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
22 * Pavel Emelianov <xemul@openvz.org>
24 * Better ipc lock (kern_ipc_perm.lock) handling
25 * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
28 #include <linux/slab.h>
30 #include <linux/hugetlb.h>
31 #include <linux/shm.h>
32 #include <linux/init.h>
33 #include <linux/file.h>
34 #include <linux/mman.h>
35 #include <linux/shmem_fs.h>
36 #include <linux/security.h>
37 #include <linux/syscalls.h>
38 #include <linux/audit.h>
39 #include <linux/capability.h>
40 #include <linux/ptrace.h>
41 #include <linux/seq_file.h>
42 #include <linux/rwsem.h>
43 #include <linux/nsproxy.h>
44 #include <linux/mount.h>
45 #include <linux/ipc_namespace.h>
46 #include <linux/rhashtable.h>
48 #include <linux/uaccess.h>
52 struct shmid_kernel
/* private to the kernel */
54 struct kern_ipc_perm shm_perm
;
55 struct file
*shm_file
;
56 unsigned long shm_nattch
;
57 unsigned long shm_segsz
;
61 struct pid
*shm_cprid
;
62 struct pid
*shm_lprid
;
63 struct ucounts
*mlock_ucounts
;
66 * The task created the shm object, for
67 * task_lock(shp->shm_creator)
69 struct task_struct
*shm_creator
;
72 * List by creator. task_lock(->shm_creator) required for read/write.
73 * If list_empty(), then the creator is dead already.
75 struct list_head shm_clist
;
76 struct ipc_namespace
*ns
;
79 /* shm_mode upper byte flags */
80 #define SHM_DEST 01000 /* segment will be destroyed on last detach */
81 #define SHM_LOCKED 02000 /* segment will not be swapped */
83 struct shm_file_data
{
85 struct ipc_namespace
*ns
;
87 const struct vm_operations_struct
*vm_ops
;
90 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
92 static const struct file_operations shm_file_operations
;
93 static const struct vm_operations_struct shm_vm_ops
;
95 #define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
97 #define shm_unlock(shp) \
98 ipc_unlock(&(shp)->shm_perm)
100 static int newseg(struct ipc_namespace
*, struct ipc_params
*);
101 static void shm_open(struct vm_area_struct
*vma
);
102 static void shm_close(struct vm_area_struct
*vma
);
103 static void shm_destroy(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
);
104 #ifdef CONFIG_PROC_FS
105 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
);
108 void shm_init_ns(struct ipc_namespace
*ns
)
110 ns
->shm_ctlmax
= SHMMAX
;
111 ns
->shm_ctlall
= SHMALL
;
112 ns
->shm_ctlmni
= SHMMNI
;
113 ns
->shm_rmid_forced
= 0;
115 ipc_init_ids(&shm_ids(ns
));
119 * Called with shm_ids.rwsem (writer) and the shp structure locked.
120 * Only shm_ids.rwsem remains locked on exit.
122 static void do_shm_rmid(struct ipc_namespace
*ns
, struct kern_ipc_perm
*ipcp
)
124 struct shmid_kernel
*shp
;
126 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
127 WARN_ON(ns
!= shp
->ns
);
129 if (shp
->shm_nattch
) {
130 shp
->shm_perm
.mode
|= SHM_DEST
;
131 /* Do not find it any more */
132 ipc_set_key_private(&shm_ids(ns
), &shp
->shm_perm
);
135 shm_destroy(ns
, shp
);
139 void shm_exit_ns(struct ipc_namespace
*ns
)
141 free_ipcs(ns
, &shm_ids(ns
), do_shm_rmid
);
142 idr_destroy(&ns
->ids
[IPC_SHM_IDS
].ipcs_idr
);
143 rhashtable_destroy(&ns
->ids
[IPC_SHM_IDS
].key_ht
);
147 static int __init
ipc_ns_init(void)
149 shm_init_ns(&init_ipc_ns
);
153 pure_initcall(ipc_ns_init
);
155 void __init
shm_init(void)
157 ipc_init_proc_interface("sysvipc/shm",
158 #if BITS_PER_LONG <= 32
159 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
161 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
163 IPC_SHM_IDS
, sysvipc_shm_proc_show
);
166 static inline struct shmid_kernel
*shm_obtain_object(struct ipc_namespace
*ns
, int id
)
168 struct kern_ipc_perm
*ipcp
= ipc_obtain_object_idr(&shm_ids(ns
), id
);
171 return ERR_CAST(ipcp
);
173 return container_of(ipcp
, struct shmid_kernel
, shm_perm
);
176 static inline struct shmid_kernel
*shm_obtain_object_check(struct ipc_namespace
*ns
, int id
)
178 struct kern_ipc_perm
*ipcp
= ipc_obtain_object_check(&shm_ids(ns
), id
);
181 return ERR_CAST(ipcp
);
183 return container_of(ipcp
, struct shmid_kernel
, shm_perm
);
187 * shm_lock_(check_) routines are called in the paths where the rwsem
188 * is not necessarily held.
190 static inline struct shmid_kernel
*shm_lock(struct ipc_namespace
*ns
, int id
)
192 struct kern_ipc_perm
*ipcp
;
195 ipcp
= ipc_obtain_object_idr(&shm_ids(ns
), id
);
199 ipc_lock_object(ipcp
);
201 * ipc_rmid() may have already freed the ID while ipc_lock_object()
202 * was spinning: here verify that the structure is still valid.
203 * Upon races with RMID, return -EIDRM, thus indicating that
204 * the ID points to a removed identifier.
206 if (ipc_valid_object(ipcp
)) {
207 /* return a locked ipc object upon success */
208 return container_of(ipcp
, struct shmid_kernel
, shm_perm
);
211 ipc_unlock_object(ipcp
);
212 ipcp
= ERR_PTR(-EIDRM
);
216 * Callers of shm_lock() must validate the status of the returned ipc
217 * object pointer and error out as appropriate.
219 return ERR_CAST(ipcp
);
222 static inline void shm_lock_by_ptr(struct shmid_kernel
*ipcp
)
225 ipc_lock_object(&ipcp
->shm_perm
);
228 static void shm_rcu_free(struct rcu_head
*head
)
230 struct kern_ipc_perm
*ptr
= container_of(head
, struct kern_ipc_perm
,
232 struct shmid_kernel
*shp
= container_of(ptr
, struct shmid_kernel
,
234 security_shm_free(&shp
->shm_perm
);
239 * It has to be called with shp locked.
240 * It must be called before ipc_rmid()
242 static inline void shm_clist_rm(struct shmid_kernel
*shp
)
244 struct task_struct
*creator
;
246 /* ensure that shm_creator does not disappear */
250 * A concurrent exit_shm may do a list_del_init() as well.
251 * Just do nothing if exit_shm already did the work
253 if (!list_empty(&shp
->shm_clist
)) {
255 * shp->shm_creator is guaranteed to be valid *only*
256 * if shp->shm_clist is not empty.
258 creator
= shp
->shm_creator
;
262 * list_del_init() is a nop if the entry was already removed
265 list_del_init(&shp
->shm_clist
);
266 task_unlock(creator
);
271 static inline void shm_rmid(struct shmid_kernel
*s
)
274 ipc_rmid(&shm_ids(s
->ns
), &s
->shm_perm
);
278 static int __shm_open(struct vm_area_struct
*vma
)
280 struct file
*file
= vma
->vm_file
;
281 struct shm_file_data
*sfd
= shm_file_data(file
);
282 struct shmid_kernel
*shp
;
284 shp
= shm_lock(sfd
->ns
, sfd
->id
);
289 if (shp
->shm_file
!= sfd
->file
) {
295 shp
->shm_atim
= ktime_get_real_seconds();
296 ipc_update_pid(&shp
->shm_lprid
, task_tgid(current
));
302 /* This is called by fork, once for every shm attach. */
303 static void shm_open(struct vm_area_struct
*vma
)
305 int err
= __shm_open(vma
);
307 * We raced in the idr lookup or with shm_destroy().
308 * Either way, the ID is busted.
314 * shm_destroy - free the struct shmid_kernel
317 * @shp: struct to free
319 * It has to be called with shp and shm_ids.rwsem (writer) locked,
320 * but returns with shp unlocked and freed.
322 static void shm_destroy(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
324 struct file
*shm_file
;
326 shm_file
= shp
->shm_file
;
327 shp
->shm_file
= NULL
;
328 ns
->shm_tot
-= (shp
->shm_segsz
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
331 if (!is_file_hugepages(shm_file
))
332 shmem_lock(shm_file
, 0, shp
->mlock_ucounts
);
333 else if (shp
->mlock_ucounts
)
334 user_shm_unlock(i_size_read(file_inode(shm_file
)),
337 ipc_update_pid(&shp
->shm_cprid
, NULL
);
338 ipc_update_pid(&shp
->shm_lprid
, NULL
);
339 ipc_rcu_putref(&shp
->shm_perm
, shm_rcu_free
);
343 * shm_may_destroy - identifies whether shm segment should be destroyed now
345 * Returns true if and only if there are no active users of the segment and
346 * one of the following is true:
348 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
350 * 2) sysctl kernel.shm_rmid_forced is set to 1.
352 static bool shm_may_destroy(struct shmid_kernel
*shp
)
354 return (shp
->shm_nattch
== 0) &&
355 (shp
->ns
->shm_rmid_forced
||
356 (shp
->shm_perm
.mode
& SHM_DEST
));
360 * remove the attach descriptor vma.
361 * free memory for segment if it is marked destroyed.
362 * The descriptor has already been removed from the current->mm->mmap list
363 * and will later be kfree()d.
365 static void shm_close(struct vm_area_struct
*vma
)
367 struct file
*file
= vma
->vm_file
;
368 struct shm_file_data
*sfd
= shm_file_data(file
);
369 struct shmid_kernel
*shp
;
370 struct ipc_namespace
*ns
= sfd
->ns
;
372 down_write(&shm_ids(ns
).rwsem
);
373 /* remove from the list of attaches of the shm segment */
374 shp
= shm_lock(ns
, sfd
->id
);
377 * We raced in the idr lookup or with shm_destroy().
378 * Either way, the ID is busted.
380 if (WARN_ON_ONCE(IS_ERR(shp
)))
381 goto done
; /* no-op */
383 ipc_update_pid(&shp
->shm_lprid
, task_tgid(current
));
384 shp
->shm_dtim
= ktime_get_real_seconds();
386 if (shm_may_destroy(shp
))
387 shm_destroy(ns
, shp
);
391 up_write(&shm_ids(ns
).rwsem
);
394 /* Called with ns->shm_ids(ns).rwsem locked */
395 static int shm_try_destroy_orphaned(int id
, void *p
, void *data
)
397 struct ipc_namespace
*ns
= data
;
398 struct kern_ipc_perm
*ipcp
= p
;
399 struct shmid_kernel
*shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
402 * We want to destroy segments without users and with already
403 * exit'ed originating process.
405 * As shp->* are changed under rwsem, it's safe to skip shp locking.
407 if (!list_empty(&shp
->shm_clist
))
410 if (shm_may_destroy(shp
)) {
411 shm_lock_by_ptr(shp
);
412 shm_destroy(ns
, shp
);
417 void shm_destroy_orphaned(struct ipc_namespace
*ns
)
419 down_write(&shm_ids(ns
).rwsem
);
420 if (shm_ids(ns
).in_use
)
421 idr_for_each(&shm_ids(ns
).ipcs_idr
, &shm_try_destroy_orphaned
, ns
);
422 up_write(&shm_ids(ns
).rwsem
);
425 /* Locking assumes this will only be called with task == current */
426 void exit_shm(struct task_struct
*task
)
429 struct shmid_kernel
*shp
;
430 struct ipc_namespace
*ns
;
434 if (list_empty(&task
->sysvshm
.shm_clist
)) {
439 shp
= list_first_entry(&task
->sysvshm
.shm_clist
, struct shmid_kernel
,
443 * 1) Get pointer to the ipc namespace. It is worth to say
444 * that this pointer is guaranteed to be valid because
445 * shp lifetime is always shorter than namespace lifetime
446 * in which shp lives.
447 * We taken task_lock it means that shp won't be freed.
452 * 2) If kernel.shm_rmid_forced is not set then only keep track of
453 * which shmids are orphaned, so that a later set of the sysctl
456 if (!ns
->shm_rmid_forced
)
457 goto unlink_continue
;
460 * 3) get a reference to the namespace.
461 * The refcount could be already 0. If it is 0, then
462 * the shm objects will be free by free_ipc_work().
464 ns
= get_ipc_ns_not_zero(ns
);
467 list_del_init(&shp
->shm_clist
);
473 * 4) get a reference to shp.
474 * This cannot fail: shm_clist_rm() is called before
475 * ipc_rmid(), thus the refcount cannot be 0.
477 WARN_ON(!ipc_rcu_getref(&shp
->shm_perm
));
480 * 5) unlink the shm segment from the list of segments
481 * created by current.
482 * This must be done last. After unlinking,
483 * only the refcounts obtained above prevent IPC_RMID
484 * from destroying the segment or the namespace.
486 list_del_init(&shp
->shm_clist
);
491 * 6) we have all references
492 * Thus lock & if needed destroy shp.
494 down_write(&shm_ids(ns
).rwsem
);
495 shm_lock_by_ptr(shp
);
497 * rcu_read_lock was implicitly taken in shm_lock_by_ptr, it's
498 * safe to call ipc_rcu_putref here
500 ipc_rcu_putref(&shp
->shm_perm
, shm_rcu_free
);
502 if (ipc_valid_object(&shp
->shm_perm
)) {
503 if (shm_may_destroy(shp
))
504 shm_destroy(ns
, shp
);
509 * Someone else deleted the shp from namespace
510 * idr/kht while we have waited.
511 * Just unlock and continue.
516 up_write(&shm_ids(ns
).rwsem
);
517 put_ipc_ns(ns
); /* paired with get_ipc_ns_not_zero */
521 static vm_fault_t
shm_fault(struct vm_fault
*vmf
)
523 struct file
*file
= vmf
->vma
->vm_file
;
524 struct shm_file_data
*sfd
= shm_file_data(file
);
526 return sfd
->vm_ops
->fault(vmf
);
529 static int shm_may_split(struct vm_area_struct
*vma
, unsigned long addr
)
531 struct file
*file
= vma
->vm_file
;
532 struct shm_file_data
*sfd
= shm_file_data(file
);
534 if (sfd
->vm_ops
->may_split
)
535 return sfd
->vm_ops
->may_split(vma
, addr
);
540 static unsigned long shm_pagesize(struct vm_area_struct
*vma
)
542 struct file
*file
= vma
->vm_file
;
543 struct shm_file_data
*sfd
= shm_file_data(file
);
545 if (sfd
->vm_ops
->pagesize
)
546 return sfd
->vm_ops
->pagesize(vma
);
552 static int shm_set_policy(struct vm_area_struct
*vma
, struct mempolicy
*new)
554 struct file
*file
= vma
->vm_file
;
555 struct shm_file_data
*sfd
= shm_file_data(file
);
558 if (sfd
->vm_ops
->set_policy
)
559 err
= sfd
->vm_ops
->set_policy(vma
, new);
563 static struct mempolicy
*shm_get_policy(struct vm_area_struct
*vma
,
566 struct file
*file
= vma
->vm_file
;
567 struct shm_file_data
*sfd
= shm_file_data(file
);
568 struct mempolicy
*pol
= NULL
;
570 if (sfd
->vm_ops
->get_policy
)
571 pol
= sfd
->vm_ops
->get_policy(vma
, addr
);
572 else if (vma
->vm_policy
)
573 pol
= vma
->vm_policy
;
579 static int shm_mmap(struct file
*file
, struct vm_area_struct
*vma
)
581 struct shm_file_data
*sfd
= shm_file_data(file
);
585 * In case of remap_file_pages() emulation, the file can represent an
586 * IPC ID that was removed, and possibly even reused by another shm
587 * segment already. Propagate this case as an error to caller.
589 ret
= __shm_open(vma
);
593 ret
= call_mmap(sfd
->file
, vma
);
598 sfd
->vm_ops
= vma
->vm_ops
;
600 WARN_ON(!sfd
->vm_ops
->fault
);
602 vma
->vm_ops
= &shm_vm_ops
;
606 static int shm_release(struct inode
*ino
, struct file
*file
)
608 struct shm_file_data
*sfd
= shm_file_data(file
);
612 shm_file_data(file
) = NULL
;
617 static int shm_fsync(struct file
*file
, loff_t start
, loff_t end
, int datasync
)
619 struct shm_file_data
*sfd
= shm_file_data(file
);
621 if (!sfd
->file
->f_op
->fsync
)
623 return sfd
->file
->f_op
->fsync(sfd
->file
, start
, end
, datasync
);
626 static long shm_fallocate(struct file
*file
, int mode
, loff_t offset
,
629 struct shm_file_data
*sfd
= shm_file_data(file
);
631 if (!sfd
->file
->f_op
->fallocate
)
633 return sfd
->file
->f_op
->fallocate(file
, mode
, offset
, len
);
636 static unsigned long shm_get_unmapped_area(struct file
*file
,
637 unsigned long addr
, unsigned long len
, unsigned long pgoff
,
640 struct shm_file_data
*sfd
= shm_file_data(file
);
642 return sfd
->file
->f_op
->get_unmapped_area(sfd
->file
, addr
, len
,
646 static const struct file_operations shm_file_operations
= {
649 .release
= shm_release
,
650 .get_unmapped_area
= shm_get_unmapped_area
,
651 .llseek
= noop_llseek
,
652 .fallocate
= shm_fallocate
,
656 * shm_file_operations_huge is now identical to shm_file_operations,
657 * but we keep it distinct for the sake of is_file_shm_hugepages().
659 static const struct file_operations shm_file_operations_huge
= {
662 .release
= shm_release
,
663 .get_unmapped_area
= shm_get_unmapped_area
,
664 .llseek
= noop_llseek
,
665 .fallocate
= shm_fallocate
,
668 bool is_file_shm_hugepages(struct file
*file
)
670 return file
->f_op
== &shm_file_operations_huge
;
673 static const struct vm_operations_struct shm_vm_ops
= {
674 .open
= shm_open
, /* callback for a new vm-area open */
675 .close
= shm_close
, /* callback for when the vm-area is released */
677 .may_split
= shm_may_split
,
678 .pagesize
= shm_pagesize
,
679 #if defined(CONFIG_NUMA)
680 .set_policy
= shm_set_policy
,
681 .get_policy
= shm_get_policy
,
686 * newseg - Create a new shared memory segment
688 * @params: ptr to the structure that contains key, size and shmflg
690 * Called with shm_ids.rwsem held as a writer.
692 static int newseg(struct ipc_namespace
*ns
, struct ipc_params
*params
)
694 key_t key
= params
->key
;
695 int shmflg
= params
->flg
;
696 size_t size
= params
->u
.size
;
698 struct shmid_kernel
*shp
;
699 size_t numpages
= (size
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
702 vm_flags_t acctflag
= 0;
704 if (size
< SHMMIN
|| size
> ns
->shm_ctlmax
)
707 if (numpages
<< PAGE_SHIFT
< size
)
710 if (ns
->shm_tot
+ numpages
< ns
->shm_tot
||
711 ns
->shm_tot
+ numpages
> ns
->shm_ctlall
)
714 shp
= kmalloc(sizeof(*shp
), GFP_KERNEL_ACCOUNT
);
718 shp
->shm_perm
.key
= key
;
719 shp
->shm_perm
.mode
= (shmflg
& S_IRWXUGO
);
720 shp
->mlock_ucounts
= NULL
;
722 shp
->shm_perm
.security
= NULL
;
723 error
= security_shm_alloc(&shp
->shm_perm
);
729 sprintf(name
, "SYSV%08x", key
);
730 if (shmflg
& SHM_HUGETLB
) {
734 hs
= hstate_sizelog((shmflg
>> SHM_HUGE_SHIFT
) & SHM_HUGE_MASK
);
739 hugesize
= ALIGN(size
, huge_page_size(hs
));
741 /* hugetlb_file_setup applies strict accounting */
742 if (shmflg
& SHM_NORESERVE
)
743 acctflag
= VM_NORESERVE
;
744 file
= hugetlb_file_setup(name
, hugesize
, acctflag
,
745 &shp
->mlock_ucounts
, HUGETLB_SHMFS_INODE
,
746 (shmflg
>> SHM_HUGE_SHIFT
) & SHM_HUGE_MASK
);
749 * Do not allow no accounting for OVERCOMMIT_NEVER, even
752 if ((shmflg
& SHM_NORESERVE
) &&
753 sysctl_overcommit_memory
!= OVERCOMMIT_NEVER
)
754 acctflag
= VM_NORESERVE
;
755 file
= shmem_kernel_file_setup(name
, size
, acctflag
);
757 error
= PTR_ERR(file
);
761 shp
->shm_cprid
= get_pid(task_tgid(current
));
762 shp
->shm_lprid
= NULL
;
763 shp
->shm_atim
= shp
->shm_dtim
= 0;
764 shp
->shm_ctim
= ktime_get_real_seconds();
765 shp
->shm_segsz
= size
;
767 shp
->shm_file
= file
;
768 shp
->shm_creator
= current
;
770 /* ipc_addid() locks shp upon success. */
771 error
= ipc_addid(&shm_ids(ns
), &shp
->shm_perm
, ns
->shm_ctlmni
);
778 list_add(&shp
->shm_clist
, ¤t
->sysvshm
.shm_clist
);
779 task_unlock(current
);
782 * shmid gets reported as "inode#" in /proc/pid/maps.
783 * proc-ps tools use this. Changing this will break them.
785 file_inode(file
)->i_ino
= shp
->shm_perm
.id
;
787 ns
->shm_tot
+= numpages
;
788 error
= shp
->shm_perm
.id
;
790 ipc_unlock_object(&shp
->shm_perm
);
795 ipc_update_pid(&shp
->shm_cprid
, NULL
);
796 ipc_update_pid(&shp
->shm_lprid
, NULL
);
797 if (is_file_hugepages(file
) && shp
->mlock_ucounts
)
798 user_shm_unlock(size
, shp
->mlock_ucounts
);
800 ipc_rcu_putref(&shp
->shm_perm
, shm_rcu_free
);
803 call_rcu(&shp
->shm_perm
.rcu
, shm_rcu_free
);
808 * Called with shm_ids.rwsem and ipcp locked.
810 static int shm_more_checks(struct kern_ipc_perm
*ipcp
, struct ipc_params
*params
)
812 struct shmid_kernel
*shp
;
814 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
815 if (shp
->shm_segsz
< params
->u
.size
)
821 long ksys_shmget(key_t key
, size_t size
, int shmflg
)
823 struct ipc_namespace
*ns
;
824 static const struct ipc_ops shm_ops
= {
826 .associate
= security_shm_associate
,
827 .more_checks
= shm_more_checks
,
829 struct ipc_params shm_params
;
831 ns
= current
->nsproxy
->ipc_ns
;
833 shm_params
.key
= key
;
834 shm_params
.flg
= shmflg
;
835 shm_params
.u
.size
= size
;
837 return ipcget(ns
, &shm_ids(ns
), &shm_ops
, &shm_params
);
840 SYSCALL_DEFINE3(shmget
, key_t
, key
, size_t, size
, int, shmflg
)
842 return ksys_shmget(key
, size
, shmflg
);
845 static inline unsigned long copy_shmid_to_user(void __user
*buf
, struct shmid64_ds
*in
, int version
)
849 return copy_to_user(buf
, in
, sizeof(*in
));
854 memset(&out
, 0, sizeof(out
));
855 ipc64_perm_to_ipc_perm(&in
->shm_perm
, &out
.shm_perm
);
856 out
.shm_segsz
= in
->shm_segsz
;
857 out
.shm_atime
= in
->shm_atime
;
858 out
.shm_dtime
= in
->shm_dtime
;
859 out
.shm_ctime
= in
->shm_ctime
;
860 out
.shm_cpid
= in
->shm_cpid
;
861 out
.shm_lpid
= in
->shm_lpid
;
862 out
.shm_nattch
= in
->shm_nattch
;
864 return copy_to_user(buf
, &out
, sizeof(out
));
871 static inline unsigned long
872 copy_shmid_from_user(struct shmid64_ds
*out
, void __user
*buf
, int version
)
876 if (copy_from_user(out
, buf
, sizeof(*out
)))
881 struct shmid_ds tbuf_old
;
883 if (copy_from_user(&tbuf_old
, buf
, sizeof(tbuf_old
)))
886 out
->shm_perm
.uid
= tbuf_old
.shm_perm
.uid
;
887 out
->shm_perm
.gid
= tbuf_old
.shm_perm
.gid
;
888 out
->shm_perm
.mode
= tbuf_old
.shm_perm
.mode
;
897 static inline unsigned long copy_shminfo_to_user(void __user
*buf
, struct shminfo64
*in
, int version
)
901 return copy_to_user(buf
, in
, sizeof(*in
));
906 if (in
->shmmax
> INT_MAX
)
907 out
.shmmax
= INT_MAX
;
909 out
.shmmax
= (int)in
->shmmax
;
911 out
.shmmin
= in
->shmmin
;
912 out
.shmmni
= in
->shmmni
;
913 out
.shmseg
= in
->shmseg
;
914 out
.shmall
= in
->shmall
;
916 return copy_to_user(buf
, &out
, sizeof(out
));
924 * Calculate and add used RSS and swap pages of a shm.
925 * Called with shm_ids.rwsem held as a reader
927 static void shm_add_rss_swap(struct shmid_kernel
*shp
,
928 unsigned long *rss_add
, unsigned long *swp_add
)
932 inode
= file_inode(shp
->shm_file
);
934 if (is_file_hugepages(shp
->shm_file
)) {
935 struct address_space
*mapping
= inode
->i_mapping
;
936 struct hstate
*h
= hstate_file(shp
->shm_file
);
937 *rss_add
+= pages_per_huge_page(h
) * mapping
->nrpages
;
940 struct shmem_inode_info
*info
= SHMEM_I(inode
);
942 spin_lock_irq(&info
->lock
);
943 *rss_add
+= inode
->i_mapping
->nrpages
;
944 *swp_add
+= info
->swapped
;
945 spin_unlock_irq(&info
->lock
);
947 *rss_add
+= inode
->i_mapping
->nrpages
;
953 * Called with shm_ids.rwsem held as a reader
955 static void shm_get_stat(struct ipc_namespace
*ns
, unsigned long *rss
,
964 in_use
= shm_ids(ns
).in_use
;
966 for (total
= 0, next_id
= 0; total
< in_use
; next_id
++) {
967 struct kern_ipc_perm
*ipc
;
968 struct shmid_kernel
*shp
;
970 ipc
= idr_find(&shm_ids(ns
).ipcs_idr
, next_id
);
973 shp
= container_of(ipc
, struct shmid_kernel
, shm_perm
);
975 shm_add_rss_swap(shp
, rss
, swp
);
982 * This function handles some shmctl commands which require the rwsem
983 * to be held in write mode.
984 * NOTE: no locks must be held, the rwsem is taken inside this function.
986 static int shmctl_down(struct ipc_namespace
*ns
, int shmid
, int cmd
,
987 struct shmid64_ds
*shmid64
)
989 struct kern_ipc_perm
*ipcp
;
990 struct shmid_kernel
*shp
;
993 down_write(&shm_ids(ns
).rwsem
);
996 ipcp
= ipcctl_obtain_check(ns
, &shm_ids(ns
), shmid
, cmd
,
997 &shmid64
->shm_perm
, 0);
1003 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
1005 err
= security_shm_shmctl(&shp
->shm_perm
, cmd
);
1011 ipc_lock_object(&shp
->shm_perm
);
1012 /* do_shm_rmid unlocks the ipc object and rcu */
1013 do_shm_rmid(ns
, ipcp
);
1016 ipc_lock_object(&shp
->shm_perm
);
1017 err
= ipc_update_perm(&shmid64
->shm_perm
, ipcp
);
1020 shp
->shm_ctim
= ktime_get_real_seconds();
1028 ipc_unlock_object(&shp
->shm_perm
);
1032 up_write(&shm_ids(ns
).rwsem
);
1036 static int shmctl_ipc_info(struct ipc_namespace
*ns
,
1037 struct shminfo64
*shminfo
)
1039 int err
= security_shm_shmctl(NULL
, IPC_INFO
);
1041 memset(shminfo
, 0, sizeof(*shminfo
));
1042 shminfo
->shmmni
= shminfo
->shmseg
= ns
->shm_ctlmni
;
1043 shminfo
->shmmax
= ns
->shm_ctlmax
;
1044 shminfo
->shmall
= ns
->shm_ctlall
;
1045 shminfo
->shmmin
= SHMMIN
;
1046 down_read(&shm_ids(ns
).rwsem
);
1047 err
= ipc_get_maxidx(&shm_ids(ns
));
1048 up_read(&shm_ids(ns
).rwsem
);
1055 static int shmctl_shm_info(struct ipc_namespace
*ns
,
1056 struct shm_info
*shm_info
)
1058 int err
= security_shm_shmctl(NULL
, SHM_INFO
);
1060 memset(shm_info
, 0, sizeof(*shm_info
));
1061 down_read(&shm_ids(ns
).rwsem
);
1062 shm_info
->used_ids
= shm_ids(ns
).in_use
;
1063 shm_get_stat(ns
, &shm_info
->shm_rss
, &shm_info
->shm_swp
);
1064 shm_info
->shm_tot
= ns
->shm_tot
;
1065 shm_info
->swap_attempts
= 0;
1066 shm_info
->swap_successes
= 0;
1067 err
= ipc_get_maxidx(&shm_ids(ns
));
1068 up_read(&shm_ids(ns
).rwsem
);
1075 static int shmctl_stat(struct ipc_namespace
*ns
, int shmid
,
1076 int cmd
, struct shmid64_ds
*tbuf
)
1078 struct shmid_kernel
*shp
;
1081 memset(tbuf
, 0, sizeof(*tbuf
));
1084 if (cmd
== SHM_STAT
|| cmd
== SHM_STAT_ANY
) {
1085 shp
= shm_obtain_object(ns
, shmid
);
1090 } else { /* IPC_STAT */
1091 shp
= shm_obtain_object_check(ns
, shmid
);
1099 * Semantically SHM_STAT_ANY ought to be identical to
1100 * that functionality provided by the /proc/sysvipc/
1101 * interface. As such, only audit these calls and
1102 * do not do traditional S_IRUGO permission checks on
1105 if (cmd
== SHM_STAT_ANY
)
1106 audit_ipc_obj(&shp
->shm_perm
);
1109 if (ipcperms(ns
, &shp
->shm_perm
, S_IRUGO
))
1113 err
= security_shm_shmctl(&shp
->shm_perm
, cmd
);
1117 ipc_lock_object(&shp
->shm_perm
);
1119 if (!ipc_valid_object(&shp
->shm_perm
)) {
1120 ipc_unlock_object(&shp
->shm_perm
);
1125 kernel_to_ipc64_perm(&shp
->shm_perm
, &tbuf
->shm_perm
);
1126 tbuf
->shm_segsz
= shp
->shm_segsz
;
1127 tbuf
->shm_atime
= shp
->shm_atim
;
1128 tbuf
->shm_dtime
= shp
->shm_dtim
;
1129 tbuf
->shm_ctime
= shp
->shm_ctim
;
1130 #ifndef CONFIG_64BIT
1131 tbuf
->shm_atime_high
= shp
->shm_atim
>> 32;
1132 tbuf
->shm_dtime_high
= shp
->shm_dtim
>> 32;
1133 tbuf
->shm_ctime_high
= shp
->shm_ctim
>> 32;
1135 tbuf
->shm_cpid
= pid_vnr(shp
->shm_cprid
);
1136 tbuf
->shm_lpid
= pid_vnr(shp
->shm_lprid
);
1137 tbuf
->shm_nattch
= shp
->shm_nattch
;
1139 if (cmd
== IPC_STAT
) {
1141 * As defined in SUS:
1142 * Return 0 on success
1147 * SHM_STAT and SHM_STAT_ANY (both Linux specific)
1148 * Return the full id, including the sequence number
1150 err
= shp
->shm_perm
.id
;
1153 ipc_unlock_object(&shp
->shm_perm
);
1159 static int shmctl_do_lock(struct ipc_namespace
*ns
, int shmid
, int cmd
)
1161 struct shmid_kernel
*shp
;
1162 struct file
*shm_file
;
1166 shp
= shm_obtain_object_check(ns
, shmid
);
1172 audit_ipc_obj(&(shp
->shm_perm
));
1173 err
= security_shm_shmctl(&shp
->shm_perm
, cmd
);
1177 ipc_lock_object(&shp
->shm_perm
);
1179 /* check if shm_destroy() is tearing down shp */
1180 if (!ipc_valid_object(&shp
->shm_perm
)) {
1185 if (!ns_capable(ns
->user_ns
, CAP_IPC_LOCK
)) {
1186 kuid_t euid
= current_euid();
1188 if (!uid_eq(euid
, shp
->shm_perm
.uid
) &&
1189 !uid_eq(euid
, shp
->shm_perm
.cuid
)) {
1193 if (cmd
== SHM_LOCK
&& !rlimit(RLIMIT_MEMLOCK
)) {
1199 shm_file
= shp
->shm_file
;
1200 if (is_file_hugepages(shm_file
))
1203 if (cmd
== SHM_LOCK
) {
1204 struct ucounts
*ucounts
= current_ucounts();
1206 err
= shmem_lock(shm_file
, 1, ucounts
);
1207 if (!err
&& !(shp
->shm_perm
.mode
& SHM_LOCKED
)) {
1208 shp
->shm_perm
.mode
|= SHM_LOCKED
;
1209 shp
->mlock_ucounts
= ucounts
;
1215 if (!(shp
->shm_perm
.mode
& SHM_LOCKED
))
1217 shmem_lock(shm_file
, 0, shp
->mlock_ucounts
);
1218 shp
->shm_perm
.mode
&= ~SHM_LOCKED
;
1219 shp
->mlock_ucounts
= NULL
;
1221 ipc_unlock_object(&shp
->shm_perm
);
1223 shmem_unlock_mapping(shm_file
->f_mapping
);
1229 ipc_unlock_object(&shp
->shm_perm
);
1235 static long ksys_shmctl(int shmid
, int cmd
, struct shmid_ds __user
*buf
, int version
)
1238 struct ipc_namespace
*ns
;
1239 struct shmid64_ds sem64
;
1241 if (cmd
< 0 || shmid
< 0)
1244 ns
= current
->nsproxy
->ipc_ns
;
1248 struct shminfo64 shminfo
;
1249 err
= shmctl_ipc_info(ns
, &shminfo
);
1252 if (copy_shminfo_to_user(buf
, &shminfo
, version
))
1257 struct shm_info shm_info
;
1258 err
= shmctl_shm_info(ns
, &shm_info
);
1261 if (copy_to_user(buf
, &shm_info
, sizeof(shm_info
)))
1268 err
= shmctl_stat(ns
, shmid
, cmd
, &sem64
);
1271 if (copy_shmid_to_user(buf
, &sem64
, version
))
1276 if (copy_shmid_from_user(&sem64
, buf
, version
))
1280 return shmctl_down(ns
, shmid
, cmd
, &sem64
);
1283 return shmctl_do_lock(ns
, shmid
, cmd
);
1289 SYSCALL_DEFINE3(shmctl
, int, shmid
, int, cmd
, struct shmid_ds __user
*, buf
)
1291 return ksys_shmctl(shmid
, cmd
, buf
, IPC_64
);
1294 #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
1295 long ksys_old_shmctl(int shmid
, int cmd
, struct shmid_ds __user
*buf
)
1297 int version
= ipc_parse_version(&cmd
);
1299 return ksys_shmctl(shmid
, cmd
, buf
, version
);
1302 SYSCALL_DEFINE3(old_shmctl
, int, shmid
, int, cmd
, struct shmid_ds __user
*, buf
)
1304 return ksys_old_shmctl(shmid
, cmd
, buf
);
1308 #ifdef CONFIG_COMPAT
1310 struct compat_shmid_ds
{
1311 struct compat_ipc_perm shm_perm
;
1313 old_time32_t shm_atime
;
1314 old_time32_t shm_dtime
;
1315 old_time32_t shm_ctime
;
1316 compat_ipc_pid_t shm_cpid
;
1317 compat_ipc_pid_t shm_lpid
;
1318 unsigned short shm_nattch
;
1319 unsigned short shm_unused
;
1320 compat_uptr_t shm_unused2
;
1321 compat_uptr_t shm_unused3
;
1324 struct compat_shminfo64
{
1325 compat_ulong_t shmmax
;
1326 compat_ulong_t shmmin
;
1327 compat_ulong_t shmmni
;
1328 compat_ulong_t shmseg
;
1329 compat_ulong_t shmall
;
1330 compat_ulong_t __unused1
;
1331 compat_ulong_t __unused2
;
1332 compat_ulong_t __unused3
;
1333 compat_ulong_t __unused4
;
1336 struct compat_shm_info
{
1337 compat_int_t used_ids
;
1338 compat_ulong_t shm_tot
, shm_rss
, shm_swp
;
1339 compat_ulong_t swap_attempts
, swap_successes
;
1342 static int copy_compat_shminfo_to_user(void __user
*buf
, struct shminfo64
*in
,
1345 if (in
->shmmax
> INT_MAX
)
1346 in
->shmmax
= INT_MAX
;
1347 if (version
== IPC_64
) {
1348 struct compat_shminfo64 info
;
1349 memset(&info
, 0, sizeof(info
));
1350 info
.shmmax
= in
->shmmax
;
1351 info
.shmmin
= in
->shmmin
;
1352 info
.shmmni
= in
->shmmni
;
1353 info
.shmseg
= in
->shmseg
;
1354 info
.shmall
= in
->shmall
;
1355 return copy_to_user(buf
, &info
, sizeof(info
));
1357 struct shminfo info
;
1358 memset(&info
, 0, sizeof(info
));
1359 info
.shmmax
= in
->shmmax
;
1360 info
.shmmin
= in
->shmmin
;
1361 info
.shmmni
= in
->shmmni
;
1362 info
.shmseg
= in
->shmseg
;
1363 info
.shmall
= in
->shmall
;
1364 return copy_to_user(buf
, &info
, sizeof(info
));
1368 static int put_compat_shm_info(struct shm_info
*ip
,
1369 struct compat_shm_info __user
*uip
)
1371 struct compat_shm_info info
;
1373 memset(&info
, 0, sizeof(info
));
1374 info
.used_ids
= ip
->used_ids
;
1375 info
.shm_tot
= ip
->shm_tot
;
1376 info
.shm_rss
= ip
->shm_rss
;
1377 info
.shm_swp
= ip
->shm_swp
;
1378 info
.swap_attempts
= ip
->swap_attempts
;
1379 info
.swap_successes
= ip
->swap_successes
;
1380 return copy_to_user(uip
, &info
, sizeof(info
));
1383 static int copy_compat_shmid_to_user(void __user
*buf
, struct shmid64_ds
*in
,
1386 if (version
== IPC_64
) {
1387 struct compat_shmid64_ds v
;
1388 memset(&v
, 0, sizeof(v
));
1389 to_compat_ipc64_perm(&v
.shm_perm
, &in
->shm_perm
);
1390 v
.shm_atime
= lower_32_bits(in
->shm_atime
);
1391 v
.shm_atime_high
= upper_32_bits(in
->shm_atime
);
1392 v
.shm_dtime
= lower_32_bits(in
->shm_dtime
);
1393 v
.shm_dtime_high
= upper_32_bits(in
->shm_dtime
);
1394 v
.shm_ctime
= lower_32_bits(in
->shm_ctime
);
1395 v
.shm_ctime_high
= upper_32_bits(in
->shm_ctime
);
1396 v
.shm_segsz
= in
->shm_segsz
;
1397 v
.shm_nattch
= in
->shm_nattch
;
1398 v
.shm_cpid
= in
->shm_cpid
;
1399 v
.shm_lpid
= in
->shm_lpid
;
1400 return copy_to_user(buf
, &v
, sizeof(v
));
1402 struct compat_shmid_ds v
;
1403 memset(&v
, 0, sizeof(v
));
1404 to_compat_ipc_perm(&v
.shm_perm
, &in
->shm_perm
);
1405 v
.shm_perm
.key
= in
->shm_perm
.key
;
1406 v
.shm_atime
= in
->shm_atime
;
1407 v
.shm_dtime
= in
->shm_dtime
;
1408 v
.shm_ctime
= in
->shm_ctime
;
1409 v
.shm_segsz
= in
->shm_segsz
;
1410 v
.shm_nattch
= in
->shm_nattch
;
1411 v
.shm_cpid
= in
->shm_cpid
;
1412 v
.shm_lpid
= in
->shm_lpid
;
1413 return copy_to_user(buf
, &v
, sizeof(v
));
1417 static int copy_compat_shmid_from_user(struct shmid64_ds
*out
, void __user
*buf
,
1420 memset(out
, 0, sizeof(*out
));
1421 if (version
== IPC_64
) {
1422 struct compat_shmid64_ds __user
*p
= buf
;
1423 return get_compat_ipc64_perm(&out
->shm_perm
, &p
->shm_perm
);
1425 struct compat_shmid_ds __user
*p
= buf
;
1426 return get_compat_ipc_perm(&out
->shm_perm
, &p
->shm_perm
);
1430 static long compat_ksys_shmctl(int shmid
, int cmd
, void __user
*uptr
, int version
)
1432 struct ipc_namespace
*ns
;
1433 struct shmid64_ds sem64
;
1436 ns
= current
->nsproxy
->ipc_ns
;
1438 if (cmd
< 0 || shmid
< 0)
1443 struct shminfo64 shminfo
;
1444 err
= shmctl_ipc_info(ns
, &shminfo
);
1447 if (copy_compat_shminfo_to_user(uptr
, &shminfo
, version
))
1452 struct shm_info shm_info
;
1453 err
= shmctl_shm_info(ns
, &shm_info
);
1456 if (put_compat_shm_info(&shm_info
, uptr
))
1463 err
= shmctl_stat(ns
, shmid
, cmd
, &sem64
);
1466 if (copy_compat_shmid_to_user(uptr
, &sem64
, version
))
1471 if (copy_compat_shmid_from_user(&sem64
, uptr
, version
))
1475 return shmctl_down(ns
, shmid
, cmd
, &sem64
);
1478 return shmctl_do_lock(ns
, shmid
, cmd
);
1485 COMPAT_SYSCALL_DEFINE3(shmctl
, int, shmid
, int, cmd
, void __user
*, uptr
)
1487 return compat_ksys_shmctl(shmid
, cmd
, uptr
, IPC_64
);
1490 #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
1491 long compat_ksys_old_shmctl(int shmid
, int cmd
, void __user
*uptr
)
1493 int version
= compat_ipc_parse_version(&cmd
);
1495 return compat_ksys_shmctl(shmid
, cmd
, uptr
, version
);
1498 COMPAT_SYSCALL_DEFINE3(old_shmctl
, int, shmid
, int, cmd
, void __user
*, uptr
)
1500 return compat_ksys_old_shmctl(shmid
, cmd
, uptr
);
1506 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1508 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1509 * "raddr" thing points to kernel space, and there has to be a wrapper around
1512 long do_shmat(int shmid
, char __user
*shmaddr
, int shmflg
,
1513 ulong
*raddr
, unsigned long shmlba
)
1515 struct shmid_kernel
*shp
;
1516 unsigned long addr
= (unsigned long)shmaddr
;
1518 struct file
*file
, *base
;
1520 unsigned long flags
= MAP_SHARED
;
1523 struct ipc_namespace
*ns
;
1524 struct shm_file_data
*sfd
;
1526 unsigned long populate
= 0;
1533 if (addr
& (shmlba
- 1)) {
1534 if (shmflg
& SHM_RND
) {
1535 addr
&= ~(shmlba
- 1); /* round down */
1538 * Ensure that the round-down is non-nil
1539 * when remapping. This can happen for
1540 * cases when addr < shmlba.
1542 if (!addr
&& (shmflg
& SHM_REMAP
))
1545 #ifndef __ARCH_FORCE_SHMLBA
1546 if (addr
& ~PAGE_MASK
)
1552 } else if ((shmflg
& SHM_REMAP
))
1555 if (shmflg
& SHM_RDONLY
) {
1560 prot
= PROT_READ
| PROT_WRITE
;
1561 acc_mode
= S_IRUGO
| S_IWUGO
;
1564 if (shmflg
& SHM_EXEC
) {
1566 acc_mode
|= S_IXUGO
;
1570 * We cannot rely on the fs check since SYSV IPC does have an
1571 * additional creator id...
1573 ns
= current
->nsproxy
->ipc_ns
;
1575 shp
= shm_obtain_object_check(ns
, shmid
);
1582 if (ipcperms(ns
, &shp
->shm_perm
, acc_mode
))
1585 err
= security_shm_shmat(&shp
->shm_perm
, shmaddr
, shmflg
);
1589 ipc_lock_object(&shp
->shm_perm
);
1591 /* check if shm_destroy() is tearing down shp */
1592 if (!ipc_valid_object(&shp
->shm_perm
)) {
1593 ipc_unlock_object(&shp
->shm_perm
);
1599 * We need to take a reference to the real shm file to prevent the
1600 * pointer from becoming stale in cases where the lifetime of the outer
1601 * file extends beyond that of the shm segment. It's not usually
1602 * possible, but it can happen during remap_file_pages() emulation as
1603 * that unmaps the memory, then does ->mmap() via file reference only.
1604 * We'll deny the ->mmap() if the shm segment was since removed, but to
1605 * detect shm ID reuse we need to compare the file pointers.
1607 base
= get_file(shp
->shm_file
);
1609 size
= i_size_read(file_inode(base
));
1610 ipc_unlock_object(&shp
->shm_perm
);
1614 sfd
= kzalloc(sizeof(*sfd
), GFP_KERNEL
);
1620 file
= alloc_file_clone(base
, f_flags
,
1621 is_file_hugepages(base
) ?
1622 &shm_file_operations_huge
:
1623 &shm_file_operations
);
1624 err
= PTR_ERR(file
);
1631 sfd
->id
= shp
->shm_perm
.id
;
1632 sfd
->ns
= get_ipc_ns(ns
);
1635 file
->private_data
= sfd
;
1637 err
= security_mmap_file(file
, prot
, flags
);
1641 if (mmap_write_lock_killable(current
->mm
)) {
1646 if (addr
&& !(shmflg
& SHM_REMAP
)) {
1648 if (addr
+ size
< addr
)
1651 if (find_vma_intersection(current
->mm
, addr
, addr
+ size
))
1655 addr
= do_mmap(file
, addr
, size
, prot
, flags
, 0, &populate
, NULL
);
1658 if (IS_ERR_VALUE(addr
))
1661 mmap_write_unlock(current
->mm
);
1663 mm_populate(addr
, populate
);
1669 down_write(&shm_ids(ns
).rwsem
);
1670 shp
= shm_lock(ns
, shmid
);
1673 if (shm_may_destroy(shp
))
1674 shm_destroy(ns
, shp
);
1677 up_write(&shm_ids(ns
).rwsem
);
1686 SYSCALL_DEFINE3(shmat
, int, shmid
, char __user
*, shmaddr
, int, shmflg
)
1691 err
= do_shmat(shmid
, shmaddr
, shmflg
, &ret
, SHMLBA
);
1694 force_successful_syscall_return();
1698 #ifdef CONFIG_COMPAT
1700 #ifndef COMPAT_SHMLBA
1701 #define COMPAT_SHMLBA SHMLBA
1704 COMPAT_SYSCALL_DEFINE3(shmat
, int, shmid
, compat_uptr_t
, shmaddr
, int, shmflg
)
1709 err
= do_shmat(shmid
, compat_ptr(shmaddr
), shmflg
, &ret
, COMPAT_SHMLBA
);
1712 force_successful_syscall_return();
1718 * detach and kill segment if marked destroyed.
1719 * The work is done in shm_close.
1721 long ksys_shmdt(char __user
*shmaddr
)
1723 struct mm_struct
*mm
= current
->mm
;
1724 struct vm_area_struct
*vma
;
1725 unsigned long addr
= (unsigned long)shmaddr
;
1726 int retval
= -EINVAL
;
1730 struct vm_area_struct
*next
;
1733 if (addr
& ~PAGE_MASK
)
1736 if (mmap_write_lock_killable(mm
))
1740 * This function tries to be smart and unmap shm segments that
1741 * were modified by partial mlock or munmap calls:
1742 * - It first determines the size of the shm segment that should be
1743 * unmapped: It searches for a vma that is backed by shm and that
1744 * started at address shmaddr. It records it's size and then unmaps
1746 * - Then it unmaps all shm vmas that started at shmaddr and that
1747 * are within the initially determined size and that are from the
1748 * same shm segment from which we determined the size.
1749 * Errors from do_munmap are ignored: the function only fails if
1750 * it's called with invalid parameters or if it's called to unmap
1751 * a part of a vma. Both calls in this function are for full vmas,
1752 * the parameters are directly copied from the vma itself and always
1753 * valid - therefore do_munmap cannot fail. (famous last words?)
1756 * If it had been mremap()'d, the starting address would not
1757 * match the usual checks anyway. So assume all vma's are
1758 * above the starting address given.
1760 vma
= find_vma(mm
, addr
);
1764 next
= vma
->vm_next
;
1767 * Check if the starting address would match, i.e. it's
1768 * a fragment created by mprotect() and/or munmap(), or it
1769 * otherwise it starts at this address with no hassles.
1771 if ((vma
->vm_ops
== &shm_vm_ops
) &&
1772 (vma
->vm_start
- addr
)/PAGE_SIZE
== vma
->vm_pgoff
) {
1775 * Record the file of the shm segment being
1776 * unmapped. With mremap(), someone could place
1777 * page from another segment but with equal offsets
1778 * in the range we are unmapping.
1780 file
= vma
->vm_file
;
1781 size
= i_size_read(file_inode(vma
->vm_file
));
1782 do_munmap(mm
, vma
->vm_start
, vma
->vm_end
- vma
->vm_start
, NULL
);
1784 * We discovered the size of the shm segment, so
1785 * break out of here and fall through to the next
1786 * loop that uses the size information to stop
1787 * searching for matching vma's.
1797 * We need look no further than the maximum address a fragment
1798 * could possibly have landed at. Also cast things to loff_t to
1799 * prevent overflows and make comparisons vs. equal-width types.
1801 size
= PAGE_ALIGN(size
);
1802 while (vma
&& (loff_t
)(vma
->vm_end
- addr
) <= size
) {
1803 next
= vma
->vm_next
;
1805 /* finding a matching vma now does not alter retval */
1806 if ((vma
->vm_ops
== &shm_vm_ops
) &&
1807 ((vma
->vm_start
- addr
)/PAGE_SIZE
== vma
->vm_pgoff
) &&
1808 (vma
->vm_file
== file
))
1809 do_munmap(mm
, vma
->vm_start
, vma
->vm_end
- vma
->vm_start
, NULL
);
1813 #else /* CONFIG_MMU */
1814 /* under NOMMU conditions, the exact address to be destroyed must be
1817 if (vma
&& vma
->vm_start
== addr
&& vma
->vm_ops
== &shm_vm_ops
) {
1818 do_munmap(mm
, vma
->vm_start
, vma
->vm_end
- vma
->vm_start
, NULL
);
1824 mmap_write_unlock(mm
);
1828 SYSCALL_DEFINE1(shmdt
, char __user
*, shmaddr
)
1830 return ksys_shmdt(shmaddr
);
1833 #ifdef CONFIG_PROC_FS
1834 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
)
1836 struct pid_namespace
*pid_ns
= ipc_seq_pid_ns(s
);
1837 struct user_namespace
*user_ns
= seq_user_ns(s
);
1838 struct kern_ipc_perm
*ipcp
= it
;
1839 struct shmid_kernel
*shp
;
1840 unsigned long rss
= 0, swp
= 0;
1842 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
1843 shm_add_rss_swap(shp
, &rss
, &swp
);
1845 #if BITS_PER_LONG <= 32
1846 #define SIZE_SPEC "%10lu"
1848 #define SIZE_SPEC "%21lu"
1852 "%10d %10d %4o " SIZE_SPEC
" %5u %5u "
1853 "%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
1854 SIZE_SPEC
" " SIZE_SPEC
"\n",
1859 pid_nr_ns(shp
->shm_cprid
, pid_ns
),
1860 pid_nr_ns(shp
->shm_lprid
, pid_ns
),
1862 from_kuid_munged(user_ns
, shp
->shm_perm
.uid
),
1863 from_kgid_munged(user_ns
, shp
->shm_perm
.gid
),
1864 from_kuid_munged(user_ns
, shp
->shm_perm
.cuid
),
1865 from_kgid_munged(user_ns
, shp
->shm_perm
.cgid
),