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 shm_file_data
*sfd
)
280 struct shmid_kernel
*shp
;
282 shp
= shm_lock(sfd
->ns
, sfd
->id
);
287 if (shp
->shm_file
!= sfd
->file
) {
293 shp
->shm_atim
= ktime_get_real_seconds();
294 ipc_update_pid(&shp
->shm_lprid
, task_tgid(current
));
300 /* This is called by fork, once for every shm attach. */
301 static void shm_open(struct vm_area_struct
*vma
)
303 struct file
*file
= vma
->vm_file
;
304 struct shm_file_data
*sfd
= shm_file_data(file
);
307 /* Always call underlying open if present */
308 if (sfd
->vm_ops
->open
)
309 sfd
->vm_ops
->open(vma
);
311 err
= __shm_open(sfd
);
313 * We raced in the idr lookup or with shm_destroy().
314 * Either way, the ID is busted.
320 * shm_destroy - free the struct shmid_kernel
323 * @shp: struct to free
325 * It has to be called with shp and shm_ids.rwsem (writer) locked,
326 * but returns with shp unlocked and freed.
328 static void shm_destroy(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
330 struct file
*shm_file
;
332 shm_file
= shp
->shm_file
;
333 shp
->shm_file
= NULL
;
334 ns
->shm_tot
-= (shp
->shm_segsz
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
337 if (!is_file_hugepages(shm_file
))
338 shmem_lock(shm_file
, 0, shp
->mlock_ucounts
);
340 ipc_update_pid(&shp
->shm_cprid
, NULL
);
341 ipc_update_pid(&shp
->shm_lprid
, NULL
);
342 ipc_rcu_putref(&shp
->shm_perm
, shm_rcu_free
);
346 * shm_may_destroy - identifies whether shm segment should be destroyed now
348 * Returns true if and only if there are no active users of the segment and
349 * one of the following is true:
351 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
353 * 2) sysctl kernel.shm_rmid_forced is set to 1.
355 static bool shm_may_destroy(struct shmid_kernel
*shp
)
357 return (shp
->shm_nattch
== 0) &&
358 (shp
->ns
->shm_rmid_forced
||
359 (shp
->shm_perm
.mode
& SHM_DEST
));
363 * remove the attach descriptor vma.
364 * free memory for segment if it is marked destroyed.
365 * The descriptor has already been removed from the current->mm->mmap list
366 * and will later be kfree()d.
368 static void __shm_close(struct shm_file_data
*sfd
)
370 struct shmid_kernel
*shp
;
371 struct ipc_namespace
*ns
= sfd
->ns
;
373 down_write(&shm_ids(ns
).rwsem
);
374 /* remove from the list of attaches of the shm segment */
375 shp
= shm_lock(ns
, sfd
->id
);
378 * We raced in the idr lookup or with shm_destroy().
379 * Either way, the ID is busted.
381 if (WARN_ON_ONCE(IS_ERR(shp
)))
382 goto done
; /* no-op */
384 ipc_update_pid(&shp
->shm_lprid
, task_tgid(current
));
385 shp
->shm_dtim
= ktime_get_real_seconds();
387 if (shm_may_destroy(shp
))
388 shm_destroy(ns
, shp
);
392 up_write(&shm_ids(ns
).rwsem
);
395 static void shm_close(struct vm_area_struct
*vma
)
397 struct file
*file
= vma
->vm_file
;
398 struct shm_file_data
*sfd
= shm_file_data(file
);
400 /* Always call underlying close if present */
401 if (sfd
->vm_ops
->close
)
402 sfd
->vm_ops
->close(vma
);
407 /* Called with ns->shm_ids(ns).rwsem locked */
408 static int shm_try_destroy_orphaned(int id
, void *p
, void *data
)
410 struct ipc_namespace
*ns
= data
;
411 struct kern_ipc_perm
*ipcp
= p
;
412 struct shmid_kernel
*shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
415 * We want to destroy segments without users and with already
416 * exit'ed originating process.
418 * As shp->* are changed under rwsem, it's safe to skip shp locking.
420 if (!list_empty(&shp
->shm_clist
))
423 if (shm_may_destroy(shp
)) {
424 shm_lock_by_ptr(shp
);
425 shm_destroy(ns
, shp
);
430 void shm_destroy_orphaned(struct ipc_namespace
*ns
)
432 down_write(&shm_ids(ns
).rwsem
);
433 if (shm_ids(ns
).in_use
)
434 idr_for_each(&shm_ids(ns
).ipcs_idr
, &shm_try_destroy_orphaned
, ns
);
435 up_write(&shm_ids(ns
).rwsem
);
438 /* Locking assumes this will only be called with task == current */
439 void exit_shm(struct task_struct
*task
)
442 struct shmid_kernel
*shp
;
443 struct ipc_namespace
*ns
;
447 if (list_empty(&task
->sysvshm
.shm_clist
)) {
452 shp
= list_first_entry(&task
->sysvshm
.shm_clist
, struct shmid_kernel
,
456 * 1) Get pointer to the ipc namespace. It is worth to say
457 * that this pointer is guaranteed to be valid because
458 * shp lifetime is always shorter than namespace lifetime
459 * in which shp lives.
460 * We taken task_lock it means that shp won't be freed.
465 * 2) If kernel.shm_rmid_forced is not set then only keep track of
466 * which shmids are orphaned, so that a later set of the sysctl
469 if (!ns
->shm_rmid_forced
)
470 goto unlink_continue
;
473 * 3) get a reference to the namespace.
474 * The refcount could be already 0. If it is 0, then
475 * the shm objects will be free by free_ipc_work().
477 ns
= get_ipc_ns_not_zero(ns
);
480 list_del_init(&shp
->shm_clist
);
486 * 4) get a reference to shp.
487 * This cannot fail: shm_clist_rm() is called before
488 * ipc_rmid(), thus the refcount cannot be 0.
490 WARN_ON(!ipc_rcu_getref(&shp
->shm_perm
));
493 * 5) unlink the shm segment from the list of segments
494 * created by current.
495 * This must be done last. After unlinking,
496 * only the refcounts obtained above prevent IPC_RMID
497 * from destroying the segment or the namespace.
499 list_del_init(&shp
->shm_clist
);
504 * 6) we have all references
505 * Thus lock & if needed destroy shp.
507 down_write(&shm_ids(ns
).rwsem
);
508 shm_lock_by_ptr(shp
);
510 * rcu_read_lock was implicitly taken in shm_lock_by_ptr, it's
511 * safe to call ipc_rcu_putref here
513 ipc_rcu_putref(&shp
->shm_perm
, shm_rcu_free
);
515 if (ipc_valid_object(&shp
->shm_perm
)) {
516 if (shm_may_destroy(shp
))
517 shm_destroy(ns
, shp
);
522 * Someone else deleted the shp from namespace
523 * idr/kht while we have waited.
524 * Just unlock and continue.
529 up_write(&shm_ids(ns
).rwsem
);
530 put_ipc_ns(ns
); /* paired with get_ipc_ns_not_zero */
534 static vm_fault_t
shm_fault(struct vm_fault
*vmf
)
536 struct file
*file
= vmf
->vma
->vm_file
;
537 struct shm_file_data
*sfd
= shm_file_data(file
);
539 return sfd
->vm_ops
->fault(vmf
);
542 static int shm_may_split(struct vm_area_struct
*vma
, unsigned long addr
)
544 struct file
*file
= vma
->vm_file
;
545 struct shm_file_data
*sfd
= shm_file_data(file
);
547 if (sfd
->vm_ops
->may_split
)
548 return sfd
->vm_ops
->may_split(vma
, addr
);
553 static unsigned long shm_pagesize(struct vm_area_struct
*vma
)
555 struct file
*file
= vma
->vm_file
;
556 struct shm_file_data
*sfd
= shm_file_data(file
);
558 if (sfd
->vm_ops
->pagesize
)
559 return sfd
->vm_ops
->pagesize(vma
);
565 static int shm_set_policy(struct vm_area_struct
*vma
, struct mempolicy
*mpol
)
567 struct shm_file_data
*sfd
= shm_file_data(vma
->vm_file
);
570 if (sfd
->vm_ops
->set_policy
)
571 err
= sfd
->vm_ops
->set_policy(vma
, mpol
);
575 static struct mempolicy
*shm_get_policy(struct vm_area_struct
*vma
,
576 unsigned long addr
, pgoff_t
*ilx
)
578 struct shm_file_data
*sfd
= shm_file_data(vma
->vm_file
);
579 struct mempolicy
*mpol
= vma
->vm_policy
;
581 if (sfd
->vm_ops
->get_policy
)
582 mpol
= sfd
->vm_ops
->get_policy(vma
, addr
, ilx
);
587 static int shm_mmap(struct file
*file
, struct vm_area_struct
*vma
)
589 struct shm_file_data
*sfd
= shm_file_data(file
);
593 * In case of remap_file_pages() emulation, the file can represent an
594 * IPC ID that was removed, and possibly even reused by another shm
595 * segment already. Propagate this case as an error to caller.
597 ret
= __shm_open(sfd
);
601 ret
= call_mmap(sfd
->file
, vma
);
606 sfd
->vm_ops
= vma
->vm_ops
;
608 WARN_ON(!sfd
->vm_ops
->fault
);
610 vma
->vm_ops
= &shm_vm_ops
;
614 static int shm_release(struct inode
*ino
, struct file
*file
)
616 struct shm_file_data
*sfd
= shm_file_data(file
);
620 shm_file_data(file
) = NULL
;
625 static int shm_fsync(struct file
*file
, loff_t start
, loff_t end
, int datasync
)
627 struct shm_file_data
*sfd
= shm_file_data(file
);
629 if (!sfd
->file
->f_op
->fsync
)
631 return sfd
->file
->f_op
->fsync(sfd
->file
, start
, end
, datasync
);
634 static long shm_fallocate(struct file
*file
, int mode
, loff_t offset
,
637 struct shm_file_data
*sfd
= shm_file_data(file
);
639 if (!sfd
->file
->f_op
->fallocate
)
641 return sfd
->file
->f_op
->fallocate(file
, mode
, offset
, len
);
644 static unsigned long shm_get_unmapped_area(struct file
*file
,
645 unsigned long addr
, unsigned long len
, unsigned long pgoff
,
648 struct shm_file_data
*sfd
= shm_file_data(file
);
650 return sfd
->file
->f_op
->get_unmapped_area(sfd
->file
, addr
, len
,
654 static const struct file_operations shm_file_operations
= {
657 .release
= shm_release
,
658 .get_unmapped_area
= shm_get_unmapped_area
,
659 .llseek
= noop_llseek
,
660 .fallocate
= shm_fallocate
,
664 * shm_file_operations_huge is now identical to shm_file_operations,
665 * but we keep it distinct for the sake of is_file_shm_hugepages().
667 static const struct file_operations shm_file_operations_huge
= {
670 .release
= shm_release
,
671 .get_unmapped_area
= shm_get_unmapped_area
,
672 .llseek
= noop_llseek
,
673 .fallocate
= shm_fallocate
,
676 bool is_file_shm_hugepages(struct file
*file
)
678 return file
->f_op
== &shm_file_operations_huge
;
681 static const struct vm_operations_struct shm_vm_ops
= {
682 .open
= shm_open
, /* callback for a new vm-area open */
683 .close
= shm_close
, /* callback for when the vm-area is released */
685 .may_split
= shm_may_split
,
686 .pagesize
= shm_pagesize
,
687 #if defined(CONFIG_NUMA)
688 .set_policy
= shm_set_policy
,
689 .get_policy
= shm_get_policy
,
694 * newseg - Create a new shared memory segment
696 * @params: ptr to the structure that contains key, size and shmflg
698 * Called with shm_ids.rwsem held as a writer.
700 static int newseg(struct ipc_namespace
*ns
, struct ipc_params
*params
)
702 key_t key
= params
->key
;
703 int shmflg
= params
->flg
;
704 size_t size
= params
->u
.size
;
706 struct shmid_kernel
*shp
;
707 size_t numpages
= (size
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
710 vm_flags_t acctflag
= 0;
712 if (size
< SHMMIN
|| size
> ns
->shm_ctlmax
)
715 if (numpages
<< PAGE_SHIFT
< size
)
718 if (ns
->shm_tot
+ numpages
< ns
->shm_tot
||
719 ns
->shm_tot
+ numpages
> ns
->shm_ctlall
)
722 shp
= kmalloc(sizeof(*shp
), GFP_KERNEL_ACCOUNT
);
726 shp
->shm_perm
.key
= key
;
727 shp
->shm_perm
.mode
= (shmflg
& S_IRWXUGO
);
728 shp
->mlock_ucounts
= NULL
;
730 shp
->shm_perm
.security
= NULL
;
731 error
= security_shm_alloc(&shp
->shm_perm
);
737 sprintf(name
, "SYSV%08x", key
);
738 if (shmflg
& SHM_HUGETLB
) {
742 hs
= hstate_sizelog((shmflg
>> SHM_HUGE_SHIFT
) & SHM_HUGE_MASK
);
747 hugesize
= ALIGN(size
, huge_page_size(hs
));
749 /* hugetlb_file_setup applies strict accounting */
750 if (shmflg
& SHM_NORESERVE
)
751 acctflag
= VM_NORESERVE
;
752 file
= hugetlb_file_setup(name
, hugesize
, acctflag
,
753 HUGETLB_SHMFS_INODE
, (shmflg
>> SHM_HUGE_SHIFT
) & SHM_HUGE_MASK
);
756 * Do not allow no accounting for OVERCOMMIT_NEVER, even
759 if ((shmflg
& SHM_NORESERVE
) &&
760 sysctl_overcommit_memory
!= OVERCOMMIT_NEVER
)
761 acctflag
= VM_NORESERVE
;
762 file
= shmem_kernel_file_setup(name
, size
, acctflag
);
764 error
= PTR_ERR(file
);
768 shp
->shm_cprid
= get_pid(task_tgid(current
));
769 shp
->shm_lprid
= NULL
;
770 shp
->shm_atim
= shp
->shm_dtim
= 0;
771 shp
->shm_ctim
= ktime_get_real_seconds();
772 shp
->shm_segsz
= size
;
774 shp
->shm_file
= file
;
775 shp
->shm_creator
= current
;
777 /* ipc_addid() locks shp upon success. */
778 error
= ipc_addid(&shm_ids(ns
), &shp
->shm_perm
, ns
->shm_ctlmni
);
785 list_add(&shp
->shm_clist
, ¤t
->sysvshm
.shm_clist
);
786 task_unlock(current
);
789 * shmid gets reported as "inode#" in /proc/pid/maps.
790 * proc-ps tools use this. Changing this will break them.
792 file_inode(file
)->i_ino
= shp
->shm_perm
.id
;
794 ns
->shm_tot
+= numpages
;
795 error
= shp
->shm_perm
.id
;
797 ipc_unlock_object(&shp
->shm_perm
);
802 ipc_update_pid(&shp
->shm_cprid
, NULL
);
803 ipc_update_pid(&shp
->shm_lprid
, NULL
);
805 ipc_rcu_putref(&shp
->shm_perm
, shm_rcu_free
);
808 call_rcu(&shp
->shm_perm
.rcu
, shm_rcu_free
);
813 * Called with shm_ids.rwsem and ipcp locked.
815 static int shm_more_checks(struct kern_ipc_perm
*ipcp
, struct ipc_params
*params
)
817 struct shmid_kernel
*shp
;
819 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
820 if (shp
->shm_segsz
< params
->u
.size
)
826 long ksys_shmget(key_t key
, size_t size
, int shmflg
)
828 struct ipc_namespace
*ns
;
829 static const struct ipc_ops shm_ops
= {
831 .associate
= security_shm_associate
,
832 .more_checks
= shm_more_checks
,
834 struct ipc_params shm_params
;
836 ns
= current
->nsproxy
->ipc_ns
;
838 shm_params
.key
= key
;
839 shm_params
.flg
= shmflg
;
840 shm_params
.u
.size
= size
;
842 return ipcget(ns
, &shm_ids(ns
), &shm_ops
, &shm_params
);
845 SYSCALL_DEFINE3(shmget
, key_t
, key
, size_t, size
, int, shmflg
)
847 return ksys_shmget(key
, size
, shmflg
);
850 static inline unsigned long copy_shmid_to_user(void __user
*buf
, struct shmid64_ds
*in
, int version
)
854 return copy_to_user(buf
, in
, sizeof(*in
));
859 memset(&out
, 0, sizeof(out
));
860 ipc64_perm_to_ipc_perm(&in
->shm_perm
, &out
.shm_perm
);
861 out
.shm_segsz
= in
->shm_segsz
;
862 out
.shm_atime
= in
->shm_atime
;
863 out
.shm_dtime
= in
->shm_dtime
;
864 out
.shm_ctime
= in
->shm_ctime
;
865 out
.shm_cpid
= in
->shm_cpid
;
866 out
.shm_lpid
= in
->shm_lpid
;
867 out
.shm_nattch
= in
->shm_nattch
;
869 return copy_to_user(buf
, &out
, sizeof(out
));
876 static inline unsigned long
877 copy_shmid_from_user(struct shmid64_ds
*out
, void __user
*buf
, int version
)
881 if (copy_from_user(out
, buf
, sizeof(*out
)))
886 struct shmid_ds tbuf_old
;
888 if (copy_from_user(&tbuf_old
, buf
, sizeof(tbuf_old
)))
891 out
->shm_perm
.uid
= tbuf_old
.shm_perm
.uid
;
892 out
->shm_perm
.gid
= tbuf_old
.shm_perm
.gid
;
893 out
->shm_perm
.mode
= tbuf_old
.shm_perm
.mode
;
902 static inline unsigned long copy_shminfo_to_user(void __user
*buf
, struct shminfo64
*in
, int version
)
906 return copy_to_user(buf
, in
, sizeof(*in
));
911 if (in
->shmmax
> INT_MAX
)
912 out
.shmmax
= INT_MAX
;
914 out
.shmmax
= (int)in
->shmmax
;
916 out
.shmmin
= in
->shmmin
;
917 out
.shmmni
= in
->shmmni
;
918 out
.shmseg
= in
->shmseg
;
919 out
.shmall
= in
->shmall
;
921 return copy_to_user(buf
, &out
, sizeof(out
));
929 * Calculate and add used RSS and swap pages of a shm.
930 * Called with shm_ids.rwsem held as a reader
932 static void shm_add_rss_swap(struct shmid_kernel
*shp
,
933 unsigned long *rss_add
, unsigned long *swp_add
)
937 inode
= file_inode(shp
->shm_file
);
939 if (is_file_hugepages(shp
->shm_file
)) {
940 struct address_space
*mapping
= inode
->i_mapping
;
941 struct hstate
*h
= hstate_file(shp
->shm_file
);
942 *rss_add
+= pages_per_huge_page(h
) * mapping
->nrpages
;
945 struct shmem_inode_info
*info
= SHMEM_I(inode
);
947 spin_lock_irq(&info
->lock
);
948 *rss_add
+= inode
->i_mapping
->nrpages
;
949 *swp_add
+= info
->swapped
;
950 spin_unlock_irq(&info
->lock
);
952 *rss_add
+= inode
->i_mapping
->nrpages
;
958 * Called with shm_ids.rwsem held as a reader
960 static void shm_get_stat(struct ipc_namespace
*ns
, unsigned long *rss
,
969 in_use
= shm_ids(ns
).in_use
;
971 for (total
= 0, next_id
= 0; total
< in_use
; next_id
++) {
972 struct kern_ipc_perm
*ipc
;
973 struct shmid_kernel
*shp
;
975 ipc
= idr_find(&shm_ids(ns
).ipcs_idr
, next_id
);
978 shp
= container_of(ipc
, struct shmid_kernel
, shm_perm
);
980 shm_add_rss_swap(shp
, rss
, swp
);
987 * This function handles some shmctl commands which require the rwsem
988 * to be held in write mode.
989 * NOTE: no locks must be held, the rwsem is taken inside this function.
991 static int shmctl_down(struct ipc_namespace
*ns
, int shmid
, int cmd
,
992 struct shmid64_ds
*shmid64
)
994 struct kern_ipc_perm
*ipcp
;
995 struct shmid_kernel
*shp
;
998 down_write(&shm_ids(ns
).rwsem
);
1001 ipcp
= ipcctl_obtain_check(ns
, &shm_ids(ns
), shmid
, cmd
,
1002 &shmid64
->shm_perm
, 0);
1004 err
= PTR_ERR(ipcp
);
1008 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
1010 err
= security_shm_shmctl(&shp
->shm_perm
, cmd
);
1016 ipc_lock_object(&shp
->shm_perm
);
1017 /* do_shm_rmid unlocks the ipc object and rcu */
1018 do_shm_rmid(ns
, ipcp
);
1021 ipc_lock_object(&shp
->shm_perm
);
1022 err
= ipc_update_perm(&shmid64
->shm_perm
, ipcp
);
1025 shp
->shm_ctim
= ktime_get_real_seconds();
1033 ipc_unlock_object(&shp
->shm_perm
);
1037 up_write(&shm_ids(ns
).rwsem
);
1041 static int shmctl_ipc_info(struct ipc_namespace
*ns
,
1042 struct shminfo64
*shminfo
)
1044 int err
= security_shm_shmctl(NULL
, IPC_INFO
);
1046 memset(shminfo
, 0, sizeof(*shminfo
));
1047 shminfo
->shmmni
= shminfo
->shmseg
= ns
->shm_ctlmni
;
1048 shminfo
->shmmax
= ns
->shm_ctlmax
;
1049 shminfo
->shmall
= ns
->shm_ctlall
;
1050 shminfo
->shmmin
= SHMMIN
;
1051 down_read(&shm_ids(ns
).rwsem
);
1052 err
= ipc_get_maxidx(&shm_ids(ns
));
1053 up_read(&shm_ids(ns
).rwsem
);
1060 static int shmctl_shm_info(struct ipc_namespace
*ns
,
1061 struct shm_info
*shm_info
)
1063 int err
= security_shm_shmctl(NULL
, SHM_INFO
);
1065 memset(shm_info
, 0, sizeof(*shm_info
));
1066 down_read(&shm_ids(ns
).rwsem
);
1067 shm_info
->used_ids
= shm_ids(ns
).in_use
;
1068 shm_get_stat(ns
, &shm_info
->shm_rss
, &shm_info
->shm_swp
);
1069 shm_info
->shm_tot
= ns
->shm_tot
;
1070 shm_info
->swap_attempts
= 0;
1071 shm_info
->swap_successes
= 0;
1072 err
= ipc_get_maxidx(&shm_ids(ns
));
1073 up_read(&shm_ids(ns
).rwsem
);
1080 static int shmctl_stat(struct ipc_namespace
*ns
, int shmid
,
1081 int cmd
, struct shmid64_ds
*tbuf
)
1083 struct shmid_kernel
*shp
;
1086 memset(tbuf
, 0, sizeof(*tbuf
));
1089 if (cmd
== SHM_STAT
|| cmd
== SHM_STAT_ANY
) {
1090 shp
= shm_obtain_object(ns
, shmid
);
1095 } else { /* IPC_STAT */
1096 shp
= shm_obtain_object_check(ns
, shmid
);
1104 * Semantically SHM_STAT_ANY ought to be identical to
1105 * that functionality provided by the /proc/sysvipc/
1106 * interface. As such, only audit these calls and
1107 * do not do traditional S_IRUGO permission checks on
1110 if (cmd
== SHM_STAT_ANY
)
1111 audit_ipc_obj(&shp
->shm_perm
);
1114 if (ipcperms(ns
, &shp
->shm_perm
, S_IRUGO
))
1118 err
= security_shm_shmctl(&shp
->shm_perm
, cmd
);
1122 ipc_lock_object(&shp
->shm_perm
);
1124 if (!ipc_valid_object(&shp
->shm_perm
)) {
1125 ipc_unlock_object(&shp
->shm_perm
);
1130 kernel_to_ipc64_perm(&shp
->shm_perm
, &tbuf
->shm_perm
);
1131 tbuf
->shm_segsz
= shp
->shm_segsz
;
1132 tbuf
->shm_atime
= shp
->shm_atim
;
1133 tbuf
->shm_dtime
= shp
->shm_dtim
;
1134 tbuf
->shm_ctime
= shp
->shm_ctim
;
1135 #ifndef CONFIG_64BIT
1136 tbuf
->shm_atime_high
= shp
->shm_atim
>> 32;
1137 tbuf
->shm_dtime_high
= shp
->shm_dtim
>> 32;
1138 tbuf
->shm_ctime_high
= shp
->shm_ctim
>> 32;
1140 tbuf
->shm_cpid
= pid_vnr(shp
->shm_cprid
);
1141 tbuf
->shm_lpid
= pid_vnr(shp
->shm_lprid
);
1142 tbuf
->shm_nattch
= shp
->shm_nattch
;
1144 if (cmd
== IPC_STAT
) {
1146 * As defined in SUS:
1147 * Return 0 on success
1152 * SHM_STAT and SHM_STAT_ANY (both Linux specific)
1153 * Return the full id, including the sequence number
1155 err
= shp
->shm_perm
.id
;
1158 ipc_unlock_object(&shp
->shm_perm
);
1164 static int shmctl_do_lock(struct ipc_namespace
*ns
, int shmid
, int cmd
)
1166 struct shmid_kernel
*shp
;
1167 struct file
*shm_file
;
1171 shp
= shm_obtain_object_check(ns
, shmid
);
1177 audit_ipc_obj(&(shp
->shm_perm
));
1178 err
= security_shm_shmctl(&shp
->shm_perm
, cmd
);
1182 ipc_lock_object(&shp
->shm_perm
);
1184 /* check if shm_destroy() is tearing down shp */
1185 if (!ipc_valid_object(&shp
->shm_perm
)) {
1190 if (!ns_capable(ns
->user_ns
, CAP_IPC_LOCK
)) {
1191 kuid_t euid
= current_euid();
1193 if (!uid_eq(euid
, shp
->shm_perm
.uid
) &&
1194 !uid_eq(euid
, shp
->shm_perm
.cuid
)) {
1198 if (cmd
== SHM_LOCK
&& !rlimit(RLIMIT_MEMLOCK
)) {
1204 shm_file
= shp
->shm_file
;
1205 if (is_file_hugepages(shm_file
))
1208 if (cmd
== SHM_LOCK
) {
1209 struct ucounts
*ucounts
= current_ucounts();
1211 err
= shmem_lock(shm_file
, 1, ucounts
);
1212 if (!err
&& !(shp
->shm_perm
.mode
& SHM_LOCKED
)) {
1213 shp
->shm_perm
.mode
|= SHM_LOCKED
;
1214 shp
->mlock_ucounts
= ucounts
;
1220 if (!(shp
->shm_perm
.mode
& SHM_LOCKED
))
1222 shmem_lock(shm_file
, 0, shp
->mlock_ucounts
);
1223 shp
->shm_perm
.mode
&= ~SHM_LOCKED
;
1224 shp
->mlock_ucounts
= NULL
;
1226 ipc_unlock_object(&shp
->shm_perm
);
1228 shmem_unlock_mapping(shm_file
->f_mapping
);
1234 ipc_unlock_object(&shp
->shm_perm
);
1240 static long ksys_shmctl(int shmid
, int cmd
, struct shmid_ds __user
*buf
, int version
)
1243 struct ipc_namespace
*ns
;
1244 struct shmid64_ds sem64
;
1246 if (cmd
< 0 || shmid
< 0)
1249 ns
= current
->nsproxy
->ipc_ns
;
1253 struct shminfo64 shminfo
;
1254 err
= shmctl_ipc_info(ns
, &shminfo
);
1257 if (copy_shminfo_to_user(buf
, &shminfo
, version
))
1262 struct shm_info shm_info
;
1263 err
= shmctl_shm_info(ns
, &shm_info
);
1266 if (copy_to_user(buf
, &shm_info
, sizeof(shm_info
)))
1273 err
= shmctl_stat(ns
, shmid
, cmd
, &sem64
);
1276 if (copy_shmid_to_user(buf
, &sem64
, version
))
1281 if (copy_shmid_from_user(&sem64
, buf
, version
))
1285 return shmctl_down(ns
, shmid
, cmd
, &sem64
);
1288 return shmctl_do_lock(ns
, shmid
, cmd
);
1294 SYSCALL_DEFINE3(shmctl
, int, shmid
, int, cmd
, struct shmid_ds __user
*, buf
)
1296 return ksys_shmctl(shmid
, cmd
, buf
, IPC_64
);
1299 #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
1300 long ksys_old_shmctl(int shmid
, int cmd
, struct shmid_ds __user
*buf
)
1302 int version
= ipc_parse_version(&cmd
);
1304 return ksys_shmctl(shmid
, cmd
, buf
, version
);
1307 SYSCALL_DEFINE3(old_shmctl
, int, shmid
, int, cmd
, struct shmid_ds __user
*, buf
)
1309 return ksys_old_shmctl(shmid
, cmd
, buf
);
1313 #ifdef CONFIG_COMPAT
1315 struct compat_shmid_ds
{
1316 struct compat_ipc_perm shm_perm
;
1318 old_time32_t shm_atime
;
1319 old_time32_t shm_dtime
;
1320 old_time32_t shm_ctime
;
1321 compat_ipc_pid_t shm_cpid
;
1322 compat_ipc_pid_t shm_lpid
;
1323 unsigned short shm_nattch
;
1324 unsigned short shm_unused
;
1325 compat_uptr_t shm_unused2
;
1326 compat_uptr_t shm_unused3
;
1329 struct compat_shminfo64
{
1330 compat_ulong_t shmmax
;
1331 compat_ulong_t shmmin
;
1332 compat_ulong_t shmmni
;
1333 compat_ulong_t shmseg
;
1334 compat_ulong_t shmall
;
1335 compat_ulong_t __unused1
;
1336 compat_ulong_t __unused2
;
1337 compat_ulong_t __unused3
;
1338 compat_ulong_t __unused4
;
1341 struct compat_shm_info
{
1342 compat_int_t used_ids
;
1343 compat_ulong_t shm_tot
, shm_rss
, shm_swp
;
1344 compat_ulong_t swap_attempts
, swap_successes
;
1347 static int copy_compat_shminfo_to_user(void __user
*buf
, struct shminfo64
*in
,
1350 if (in
->shmmax
> INT_MAX
)
1351 in
->shmmax
= INT_MAX
;
1352 if (version
== IPC_64
) {
1353 struct compat_shminfo64 info
;
1354 memset(&info
, 0, sizeof(info
));
1355 info
.shmmax
= in
->shmmax
;
1356 info
.shmmin
= in
->shmmin
;
1357 info
.shmmni
= in
->shmmni
;
1358 info
.shmseg
= in
->shmseg
;
1359 info
.shmall
= in
->shmall
;
1360 return copy_to_user(buf
, &info
, sizeof(info
));
1362 struct shminfo info
;
1363 memset(&info
, 0, sizeof(info
));
1364 info
.shmmax
= in
->shmmax
;
1365 info
.shmmin
= in
->shmmin
;
1366 info
.shmmni
= in
->shmmni
;
1367 info
.shmseg
= in
->shmseg
;
1368 info
.shmall
= in
->shmall
;
1369 return copy_to_user(buf
, &info
, sizeof(info
));
1373 static int put_compat_shm_info(struct shm_info
*ip
,
1374 struct compat_shm_info __user
*uip
)
1376 struct compat_shm_info info
;
1378 memset(&info
, 0, sizeof(info
));
1379 info
.used_ids
= ip
->used_ids
;
1380 info
.shm_tot
= ip
->shm_tot
;
1381 info
.shm_rss
= ip
->shm_rss
;
1382 info
.shm_swp
= ip
->shm_swp
;
1383 info
.swap_attempts
= ip
->swap_attempts
;
1384 info
.swap_successes
= ip
->swap_successes
;
1385 return copy_to_user(uip
, &info
, sizeof(info
));
1388 static int copy_compat_shmid_to_user(void __user
*buf
, struct shmid64_ds
*in
,
1391 if (version
== IPC_64
) {
1392 struct compat_shmid64_ds v
;
1393 memset(&v
, 0, sizeof(v
));
1394 to_compat_ipc64_perm(&v
.shm_perm
, &in
->shm_perm
);
1395 v
.shm_atime
= lower_32_bits(in
->shm_atime
);
1396 v
.shm_atime_high
= upper_32_bits(in
->shm_atime
);
1397 v
.shm_dtime
= lower_32_bits(in
->shm_dtime
);
1398 v
.shm_dtime_high
= upper_32_bits(in
->shm_dtime
);
1399 v
.shm_ctime
= lower_32_bits(in
->shm_ctime
);
1400 v
.shm_ctime_high
= upper_32_bits(in
->shm_ctime
);
1401 v
.shm_segsz
= in
->shm_segsz
;
1402 v
.shm_nattch
= in
->shm_nattch
;
1403 v
.shm_cpid
= in
->shm_cpid
;
1404 v
.shm_lpid
= in
->shm_lpid
;
1405 return copy_to_user(buf
, &v
, sizeof(v
));
1407 struct compat_shmid_ds v
;
1408 memset(&v
, 0, sizeof(v
));
1409 to_compat_ipc_perm(&v
.shm_perm
, &in
->shm_perm
);
1410 v
.shm_perm
.key
= in
->shm_perm
.key
;
1411 v
.shm_atime
= in
->shm_atime
;
1412 v
.shm_dtime
= in
->shm_dtime
;
1413 v
.shm_ctime
= in
->shm_ctime
;
1414 v
.shm_segsz
= in
->shm_segsz
;
1415 v
.shm_nattch
= in
->shm_nattch
;
1416 v
.shm_cpid
= in
->shm_cpid
;
1417 v
.shm_lpid
= in
->shm_lpid
;
1418 return copy_to_user(buf
, &v
, sizeof(v
));
1422 static int copy_compat_shmid_from_user(struct shmid64_ds
*out
, void __user
*buf
,
1425 memset(out
, 0, sizeof(*out
));
1426 if (version
== IPC_64
) {
1427 struct compat_shmid64_ds __user
*p
= buf
;
1428 return get_compat_ipc64_perm(&out
->shm_perm
, &p
->shm_perm
);
1430 struct compat_shmid_ds __user
*p
= buf
;
1431 return get_compat_ipc_perm(&out
->shm_perm
, &p
->shm_perm
);
1435 static long compat_ksys_shmctl(int shmid
, int cmd
, void __user
*uptr
, int version
)
1437 struct ipc_namespace
*ns
;
1438 struct shmid64_ds sem64
;
1441 ns
= current
->nsproxy
->ipc_ns
;
1443 if (cmd
< 0 || shmid
< 0)
1448 struct shminfo64 shminfo
;
1449 err
= shmctl_ipc_info(ns
, &shminfo
);
1452 if (copy_compat_shminfo_to_user(uptr
, &shminfo
, version
))
1457 struct shm_info shm_info
;
1458 err
= shmctl_shm_info(ns
, &shm_info
);
1461 if (put_compat_shm_info(&shm_info
, uptr
))
1468 err
= shmctl_stat(ns
, shmid
, cmd
, &sem64
);
1471 if (copy_compat_shmid_to_user(uptr
, &sem64
, version
))
1476 if (copy_compat_shmid_from_user(&sem64
, uptr
, version
))
1480 return shmctl_down(ns
, shmid
, cmd
, &sem64
);
1483 return shmctl_do_lock(ns
, shmid
, cmd
);
1490 COMPAT_SYSCALL_DEFINE3(shmctl
, int, shmid
, int, cmd
, void __user
*, uptr
)
1492 return compat_ksys_shmctl(shmid
, cmd
, uptr
, IPC_64
);
1495 #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
1496 long compat_ksys_old_shmctl(int shmid
, int cmd
, void __user
*uptr
)
1498 int version
= compat_ipc_parse_version(&cmd
);
1500 return compat_ksys_shmctl(shmid
, cmd
, uptr
, version
);
1503 COMPAT_SYSCALL_DEFINE3(old_shmctl
, int, shmid
, int, cmd
, void __user
*, uptr
)
1505 return compat_ksys_old_shmctl(shmid
, cmd
, uptr
);
1511 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1513 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1514 * "raddr" thing points to kernel space, and there has to be a wrapper around
1517 long do_shmat(int shmid
, char __user
*shmaddr
, int shmflg
,
1518 ulong
*raddr
, unsigned long shmlba
)
1520 struct shmid_kernel
*shp
;
1521 unsigned long addr
= (unsigned long)shmaddr
;
1523 struct file
*file
, *base
;
1525 unsigned long flags
= MAP_SHARED
;
1528 struct ipc_namespace
*ns
;
1529 struct shm_file_data
*sfd
;
1531 unsigned long populate
= 0;
1538 if (addr
& (shmlba
- 1)) {
1539 if (shmflg
& SHM_RND
) {
1540 addr
&= ~(shmlba
- 1); /* round down */
1543 * Ensure that the round-down is non-nil
1544 * when remapping. This can happen for
1545 * cases when addr < shmlba.
1547 if (!addr
&& (shmflg
& SHM_REMAP
))
1550 #ifndef __ARCH_FORCE_SHMLBA
1551 if (addr
& ~PAGE_MASK
)
1557 } else if ((shmflg
& SHM_REMAP
))
1560 if (shmflg
& SHM_RDONLY
) {
1565 prot
= PROT_READ
| PROT_WRITE
;
1566 acc_mode
= S_IRUGO
| S_IWUGO
;
1569 if (shmflg
& SHM_EXEC
) {
1571 acc_mode
|= S_IXUGO
;
1575 * We cannot rely on the fs check since SYSV IPC does have an
1576 * additional creator id...
1578 ns
= current
->nsproxy
->ipc_ns
;
1580 shp
= shm_obtain_object_check(ns
, shmid
);
1587 if (ipcperms(ns
, &shp
->shm_perm
, acc_mode
))
1590 err
= security_shm_shmat(&shp
->shm_perm
, shmaddr
, shmflg
);
1594 ipc_lock_object(&shp
->shm_perm
);
1596 /* check if shm_destroy() is tearing down shp */
1597 if (!ipc_valid_object(&shp
->shm_perm
)) {
1598 ipc_unlock_object(&shp
->shm_perm
);
1604 * We need to take a reference to the real shm file to prevent the
1605 * pointer from becoming stale in cases where the lifetime of the outer
1606 * file extends beyond that of the shm segment. It's not usually
1607 * possible, but it can happen during remap_file_pages() emulation as
1608 * that unmaps the memory, then does ->mmap() via file reference only.
1609 * We'll deny the ->mmap() if the shm segment was since removed, but to
1610 * detect shm ID reuse we need to compare the file pointers.
1612 base
= get_file(shp
->shm_file
);
1614 size
= i_size_read(file_inode(base
));
1615 ipc_unlock_object(&shp
->shm_perm
);
1619 sfd
= kzalloc(sizeof(*sfd
), GFP_KERNEL
);
1625 file
= alloc_file_clone(base
, f_flags
,
1626 is_file_hugepages(base
) ?
1627 &shm_file_operations_huge
:
1628 &shm_file_operations
);
1629 err
= PTR_ERR(file
);
1636 sfd
->id
= shp
->shm_perm
.id
;
1637 sfd
->ns
= get_ipc_ns(ns
);
1640 file
->private_data
= sfd
;
1642 err
= security_mmap_file(file
, prot
, flags
);
1646 if (mmap_write_lock_killable(current
->mm
)) {
1651 if (addr
&& !(shmflg
& SHM_REMAP
)) {
1653 if (addr
+ size
< addr
)
1656 if (find_vma_intersection(current
->mm
, addr
, addr
+ size
))
1660 addr
= do_mmap(file
, addr
, size
, prot
, flags
, 0, 0, &populate
, NULL
);
1663 if (IS_ERR_VALUE(addr
))
1666 mmap_write_unlock(current
->mm
);
1668 mm_populate(addr
, populate
);
1674 down_write(&shm_ids(ns
).rwsem
);
1675 shp
= shm_lock(ns
, shmid
);
1678 if (shm_may_destroy(shp
))
1679 shm_destroy(ns
, shp
);
1682 up_write(&shm_ids(ns
).rwsem
);
1691 SYSCALL_DEFINE3(shmat
, int, shmid
, char __user
*, shmaddr
, int, shmflg
)
1696 err
= do_shmat(shmid
, shmaddr
, shmflg
, &ret
, SHMLBA
);
1699 force_successful_syscall_return();
1703 #ifdef CONFIG_COMPAT
1705 #ifndef COMPAT_SHMLBA
1706 #define COMPAT_SHMLBA SHMLBA
1709 COMPAT_SYSCALL_DEFINE3(shmat
, int, shmid
, compat_uptr_t
, shmaddr
, int, shmflg
)
1714 err
= do_shmat(shmid
, compat_ptr(shmaddr
), shmflg
, &ret
, COMPAT_SHMLBA
);
1717 force_successful_syscall_return();
1723 * detach and kill segment if marked destroyed.
1724 * The work is done in shm_close.
1726 long ksys_shmdt(char __user
*shmaddr
)
1728 struct mm_struct
*mm
= current
->mm
;
1729 struct vm_area_struct
*vma
;
1730 unsigned long addr
= (unsigned long)shmaddr
;
1731 int retval
= -EINVAL
;
1735 VMA_ITERATOR(vmi
, mm
, addr
);
1738 if (addr
& ~PAGE_MASK
)
1741 if (mmap_write_lock_killable(mm
))
1745 * This function tries to be smart and unmap shm segments that
1746 * were modified by partial mlock or munmap calls:
1747 * - It first determines the size of the shm segment that should be
1748 * unmapped: It searches for a vma that is backed by shm and that
1749 * started at address shmaddr. It records it's size and then unmaps
1751 * - Then it unmaps all shm vmas that started at shmaddr and that
1752 * are within the initially determined size and that are from the
1753 * same shm segment from which we determined the size.
1754 * Errors from do_munmap are ignored: the function only fails if
1755 * it's called with invalid parameters or if it's called to unmap
1756 * a part of a vma. Both calls in this function are for full vmas,
1757 * the parameters are directly copied from the vma itself and always
1758 * valid - therefore do_munmap cannot fail. (famous last words?)
1761 * If it had been mremap()'d, the starting address would not
1762 * match the usual checks anyway. So assume all vma's are
1763 * above the starting address given.
1767 for_each_vma(vmi
, vma
) {
1769 * Check if the starting address would match, i.e. it's
1770 * a fragment created by mprotect() and/or munmap(), or it
1771 * otherwise it starts at this address with no hassles.
1773 if ((vma
->vm_ops
== &shm_vm_ops
) &&
1774 (vma
->vm_start
- addr
)/PAGE_SIZE
== vma
->vm_pgoff
) {
1777 * Record the file of the shm segment being
1778 * unmapped. With mremap(), someone could place
1779 * page from another segment but with equal offsets
1780 * in the range we are unmapping.
1782 file
= vma
->vm_file
;
1783 size
= i_size_read(file_inode(vma
->vm_file
));
1784 do_vma_munmap(&vmi
, vma
, vma
->vm_start
, vma
->vm_end
,
1787 * We discovered the size of the shm segment, so
1788 * break out of here and fall through to the next
1789 * loop that uses the size information to stop
1790 * searching for matching vma's.
1793 vma
= vma_next(&vmi
);
1799 * We need look no further than the maximum address a fragment
1800 * could possibly have landed at. Also cast things to loff_t to
1801 * prevent overflows and make comparisons vs. equal-width types.
1803 size
= PAGE_ALIGN(size
);
1804 while (vma
&& (loff_t
)(vma
->vm_end
- addr
) <= size
) {
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_vma_munmap(&vmi
, vma
, vma
->vm_start
, vma
->vm_end
,
1813 vma
= vma_next(&vmi
);
1816 #else /* CONFIG_MMU */
1817 vma
= vma_lookup(mm
, addr
);
1818 /* under NOMMU conditions, the exact address to be destroyed must be
1821 if (vma
&& vma
->vm_start
== addr
&& vma
->vm_ops
== &shm_vm_ops
) {
1822 do_munmap(mm
, vma
->vm_start
, vma
->vm_end
- vma
->vm_start
, NULL
);
1828 mmap_write_unlock(mm
);
1832 SYSCALL_DEFINE1(shmdt
, char __user
*, shmaddr
)
1834 return ksys_shmdt(shmaddr
);
1837 #ifdef CONFIG_PROC_FS
1838 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
)
1840 struct pid_namespace
*pid_ns
= ipc_seq_pid_ns(s
);
1841 struct user_namespace
*user_ns
= seq_user_ns(s
);
1842 struct kern_ipc_perm
*ipcp
= it
;
1843 struct shmid_kernel
*shp
;
1844 unsigned long rss
= 0, swp
= 0;
1846 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
1847 shm_add_rss_swap(shp
, &rss
, &swp
);
1849 #if BITS_PER_LONG <= 32
1850 #define SIZE_SPEC "%10lu"
1852 #define SIZE_SPEC "%21lu"
1856 "%10d %10d %4o " SIZE_SPEC
" %5u %5u "
1857 "%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
1858 SIZE_SPEC
" " SIZE_SPEC
"\n",
1863 pid_nr_ns(shp
->shm_cprid
, pid_ns
),
1864 pid_nr_ns(shp
->shm_lprid
, pid_ns
),
1866 from_kuid_munged(user_ns
, shp
->shm_perm
.uid
),
1867 from_kgid_munged(user_ns
, shp
->shm_perm
.gid
),
1868 from_kuid_munged(user_ns
, shp
->shm_perm
.cuid
),
1869 from_kgid_munged(user_ns
, shp
->shm_perm
.cgid
),