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 <uapi/linux/shm.h>
33 #include <linux/init.h>
34 #include <linux/file.h>
35 #include <linux/mman.h>
36 #include <linux/shmem_fs.h>
37 #include <linux/security.h>
38 #include <linux/syscalls.h>
39 #include <linux/audit.h>
40 #include <linux/capability.h>
41 #include <linux/ptrace.h>
42 #include <linux/seq_file.h>
43 #include <linux/rwsem.h>
44 #include <linux/nsproxy.h>
45 #include <linux/mount.h>
46 #include <linux/ipc_namespace.h>
47 #include <linux/rhashtable.h>
49 #include <linux/uaccess.h>
53 struct shmid_kernel
/* private to the kernel */
55 struct kern_ipc_perm shm_perm
;
56 struct file
*shm_file
;
57 unsigned long shm_nattch
;
58 unsigned long shm_segsz
;
62 struct pid
*shm_cprid
;
63 struct pid
*shm_lprid
;
64 struct ucounts
*mlock_ucounts
;
67 * The task created the shm object, for
68 * task_lock(shp->shm_creator)
70 struct task_struct
*shm_creator
;
73 * List by creator. task_lock(->shm_creator) required for read/write.
74 * If list_empty(), then the creator is dead already.
76 struct list_head shm_clist
;
77 struct ipc_namespace
*ns
;
80 /* shm_mode upper byte flags */
81 #define SHM_DEST 01000 /* segment will be destroyed on last detach */
82 #define SHM_LOCKED 02000 /* segment will not be swapped */
84 struct shm_file_data
{
86 struct ipc_namespace
*ns
;
88 const struct vm_operations_struct
*vm_ops
;
91 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
93 static const struct file_operations shm_file_operations
;
94 static const struct vm_operations_struct shm_vm_ops
;
96 #define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
98 #define shm_unlock(shp) \
99 ipc_unlock(&(shp)->shm_perm)
101 static int newseg(struct ipc_namespace
*, struct ipc_params
*);
102 static void shm_open(struct vm_area_struct
*vma
);
103 static void shm_close(struct vm_area_struct
*vma
);
104 static void shm_destroy(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
);
105 #ifdef CONFIG_PROC_FS
106 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
);
109 void shm_init_ns(struct ipc_namespace
*ns
)
111 ns
->shm_ctlmax
= SHMMAX
;
112 ns
->shm_ctlall
= SHMALL
;
113 ns
->shm_ctlmni
= SHMMNI
;
114 ns
->shm_rmid_forced
= 0;
116 ipc_init_ids(&shm_ids(ns
));
120 * Called with shm_ids.rwsem (writer) and the shp structure locked.
121 * Only shm_ids.rwsem remains locked on exit.
123 static void do_shm_rmid(struct ipc_namespace
*ns
, struct kern_ipc_perm
*ipcp
)
125 struct shmid_kernel
*shp
;
127 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
128 WARN_ON(ns
!= shp
->ns
);
130 if (shp
->shm_nattch
) {
131 shp
->shm_perm
.mode
|= SHM_DEST
;
132 /* Do not find it any more */
133 ipc_set_key_private(&shm_ids(ns
), &shp
->shm_perm
);
136 shm_destroy(ns
, shp
);
140 void shm_exit_ns(struct ipc_namespace
*ns
)
142 free_ipcs(ns
, &shm_ids(ns
), do_shm_rmid
);
143 idr_destroy(&ns
->ids
[IPC_SHM_IDS
].ipcs_idr
);
144 rhashtable_destroy(&ns
->ids
[IPC_SHM_IDS
].key_ht
);
148 static int __init
ipc_ns_init(void)
150 shm_init_ns(&init_ipc_ns
);
154 pure_initcall(ipc_ns_init
);
156 void __init
shm_init(void)
158 ipc_init_proc_interface("sysvipc/shm",
159 #if BITS_PER_LONG <= 32
160 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
162 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
164 IPC_SHM_IDS
, sysvipc_shm_proc_show
);
167 static inline struct shmid_kernel
*shm_obtain_object(struct ipc_namespace
*ns
, int id
)
169 struct kern_ipc_perm
*ipcp
= ipc_obtain_object_idr(&shm_ids(ns
), id
);
172 return ERR_CAST(ipcp
);
174 return container_of(ipcp
, struct shmid_kernel
, shm_perm
);
177 static inline struct shmid_kernel
*shm_obtain_object_check(struct ipc_namespace
*ns
, int id
)
179 struct kern_ipc_perm
*ipcp
= ipc_obtain_object_check(&shm_ids(ns
), id
);
182 return ERR_CAST(ipcp
);
184 return container_of(ipcp
, struct shmid_kernel
, shm_perm
);
188 * shm_lock_(check_) routines are called in the paths where the rwsem
189 * is not necessarily held.
191 static inline struct shmid_kernel
*shm_lock(struct ipc_namespace
*ns
, int id
)
193 struct kern_ipc_perm
*ipcp
;
196 ipcp
= ipc_obtain_object_idr(&shm_ids(ns
), id
);
200 ipc_lock_object(ipcp
);
202 * ipc_rmid() may have already freed the ID while ipc_lock_object()
203 * was spinning: here verify that the structure is still valid.
204 * Upon races with RMID, return -EIDRM, thus indicating that
205 * the ID points to a removed identifier.
207 if (ipc_valid_object(ipcp
)) {
208 /* return a locked ipc object upon success */
209 return container_of(ipcp
, struct shmid_kernel
, shm_perm
);
212 ipc_unlock_object(ipcp
);
213 ipcp
= ERR_PTR(-EIDRM
);
217 * Callers of shm_lock() must validate the status of the returned ipc
218 * object pointer and error out as appropriate.
220 return ERR_CAST(ipcp
);
223 static inline void shm_lock_by_ptr(struct shmid_kernel
*ipcp
)
226 ipc_lock_object(&ipcp
->shm_perm
);
229 static void shm_rcu_free(struct rcu_head
*head
)
231 struct kern_ipc_perm
*ptr
= container_of(head
, struct kern_ipc_perm
,
233 struct shmid_kernel
*shp
= container_of(ptr
, struct shmid_kernel
,
235 security_shm_free(&shp
->shm_perm
);
240 * It has to be called with shp locked.
241 * It must be called before ipc_rmid()
243 static inline void shm_clist_rm(struct shmid_kernel
*shp
)
245 struct task_struct
*creator
;
247 /* ensure that shm_creator does not disappear */
251 * A concurrent exit_shm may do a list_del_init() as well.
252 * Just do nothing if exit_shm already did the work
254 if (!list_empty(&shp
->shm_clist
)) {
256 * shp->shm_creator is guaranteed to be valid *only*
257 * if shp->shm_clist is not empty.
259 creator
= shp
->shm_creator
;
263 * list_del_init() is a nop if the entry was already removed
266 list_del_init(&shp
->shm_clist
);
267 task_unlock(creator
);
272 static inline void shm_rmid(struct shmid_kernel
*s
)
275 ipc_rmid(&shm_ids(s
->ns
), &s
->shm_perm
);
279 static int __shm_open(struct shm_file_data
*sfd
)
281 struct shmid_kernel
*shp
;
283 shp
= shm_lock(sfd
->ns
, sfd
->id
);
288 if (shp
->shm_file
!= sfd
->file
) {
294 shp
->shm_atim
= ktime_get_real_seconds();
295 ipc_update_pid(&shp
->shm_lprid
, task_tgid(current
));
301 /* This is called by fork, once for every shm attach. */
302 static void shm_open(struct vm_area_struct
*vma
)
304 struct file
*file
= vma
->vm_file
;
305 struct shm_file_data
*sfd
= shm_file_data(file
);
308 /* Always call underlying open if present */
309 if (sfd
->vm_ops
->open
)
310 sfd
->vm_ops
->open(vma
);
312 err
= __shm_open(sfd
);
314 * We raced in the idr lookup or with shm_destroy().
315 * Either way, the ID is busted.
321 * shm_destroy - free the struct shmid_kernel
324 * @shp: struct to free
326 * It has to be called with shp and shm_ids.rwsem (writer) locked,
327 * but returns with shp unlocked and freed.
329 static void shm_destroy(struct ipc_namespace
*ns
, struct shmid_kernel
*shp
)
331 struct file
*shm_file
;
333 shm_file
= shp
->shm_file
;
334 shp
->shm_file
= NULL
;
335 ns
->shm_tot
-= (shp
->shm_segsz
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
338 if (!is_file_hugepages(shm_file
))
339 shmem_lock(shm_file
, 0, shp
->mlock_ucounts
);
341 ipc_update_pid(&shp
->shm_cprid
, NULL
);
342 ipc_update_pid(&shp
->shm_lprid
, NULL
);
343 ipc_rcu_putref(&shp
->shm_perm
, shm_rcu_free
);
347 * shm_may_destroy - identifies whether shm segment should be destroyed now
349 * Returns true if and only if there are no active users of the segment and
350 * one of the following is true:
352 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
354 * 2) sysctl kernel.shm_rmid_forced is set to 1.
356 static bool shm_may_destroy(struct shmid_kernel
*shp
)
358 return (shp
->shm_nattch
== 0) &&
359 (shp
->ns
->shm_rmid_forced
||
360 (shp
->shm_perm
.mode
& SHM_DEST
));
364 * remove the attach descriptor vma.
365 * free memory for segment if it is marked destroyed.
366 * The descriptor has already been removed from the current->mm->mmap list
367 * and will later be kfree()d.
369 static void __shm_close(struct shm_file_data
*sfd
)
371 struct shmid_kernel
*shp
;
372 struct ipc_namespace
*ns
= sfd
->ns
;
374 down_write(&shm_ids(ns
).rwsem
);
375 /* remove from the list of attaches of the shm segment */
376 shp
= shm_lock(ns
, sfd
->id
);
379 * We raced in the idr lookup or with shm_destroy().
380 * Either way, the ID is busted.
382 if (WARN_ON_ONCE(IS_ERR(shp
)))
383 goto done
; /* no-op */
385 ipc_update_pid(&shp
->shm_lprid
, task_tgid(current
));
386 shp
->shm_dtim
= ktime_get_real_seconds();
388 if (shm_may_destroy(shp
))
389 shm_destroy(ns
, shp
);
393 up_write(&shm_ids(ns
).rwsem
);
396 static void shm_close(struct vm_area_struct
*vma
)
398 struct file
*file
= vma
->vm_file
;
399 struct shm_file_data
*sfd
= shm_file_data(file
);
401 /* Always call underlying close if present */
402 if (sfd
->vm_ops
->close
)
403 sfd
->vm_ops
->close(vma
);
408 /* Called with ns->shm_ids(ns).rwsem locked */
409 static int shm_try_destroy_orphaned(int id
, void *p
, void *data
)
411 struct ipc_namespace
*ns
= data
;
412 struct kern_ipc_perm
*ipcp
= p
;
413 struct shmid_kernel
*shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
416 * We want to destroy segments without users and with already
417 * exit'ed originating process.
419 * As shp->* are changed under rwsem, it's safe to skip shp locking.
421 if (!list_empty(&shp
->shm_clist
))
424 if (shm_may_destroy(shp
)) {
425 shm_lock_by_ptr(shp
);
426 shm_destroy(ns
, shp
);
431 void shm_destroy_orphaned(struct ipc_namespace
*ns
)
433 down_write(&shm_ids(ns
).rwsem
);
434 if (shm_ids(ns
).in_use
)
435 idr_for_each(&shm_ids(ns
).ipcs_idr
, &shm_try_destroy_orphaned
, ns
);
436 up_write(&shm_ids(ns
).rwsem
);
439 /* Locking assumes this will only be called with task == current */
440 void exit_shm(struct task_struct
*task
)
443 struct shmid_kernel
*shp
;
444 struct ipc_namespace
*ns
;
448 if (list_empty(&task
->sysvshm
.shm_clist
)) {
453 shp
= list_first_entry(&task
->sysvshm
.shm_clist
, struct shmid_kernel
,
457 * 1) Get pointer to the ipc namespace. It is worth to say
458 * that this pointer is guaranteed to be valid because
459 * shp lifetime is always shorter than namespace lifetime
460 * in which shp lives.
461 * We taken task_lock it means that shp won't be freed.
466 * 2) If kernel.shm_rmid_forced is not set then only keep track of
467 * which shmids are orphaned, so that a later set of the sysctl
470 if (!ns
->shm_rmid_forced
)
471 goto unlink_continue
;
474 * 3) get a reference to the namespace.
475 * The refcount could be already 0. If it is 0, then
476 * the shm objects will be free by free_ipc_work().
478 ns
= get_ipc_ns_not_zero(ns
);
481 list_del_init(&shp
->shm_clist
);
487 * 4) get a reference to shp.
488 * This cannot fail: shm_clist_rm() is called before
489 * ipc_rmid(), thus the refcount cannot be 0.
491 WARN_ON(!ipc_rcu_getref(&shp
->shm_perm
));
494 * 5) unlink the shm segment from the list of segments
495 * created by current.
496 * This must be done last. After unlinking,
497 * only the refcounts obtained above prevent IPC_RMID
498 * from destroying the segment or the namespace.
500 list_del_init(&shp
->shm_clist
);
505 * 6) we have all references
506 * Thus lock & if needed destroy shp.
508 down_write(&shm_ids(ns
).rwsem
);
509 shm_lock_by_ptr(shp
);
511 * rcu_read_lock was implicitly taken in shm_lock_by_ptr, it's
512 * safe to call ipc_rcu_putref here
514 ipc_rcu_putref(&shp
->shm_perm
, shm_rcu_free
);
516 if (ipc_valid_object(&shp
->shm_perm
)) {
517 if (shm_may_destroy(shp
))
518 shm_destroy(ns
, shp
);
523 * Someone else deleted the shp from namespace
524 * idr/kht while we have waited.
525 * Just unlock and continue.
530 up_write(&shm_ids(ns
).rwsem
);
531 put_ipc_ns(ns
); /* paired with get_ipc_ns_not_zero */
535 static vm_fault_t
shm_fault(struct vm_fault
*vmf
)
537 struct file
*file
= vmf
->vma
->vm_file
;
538 struct shm_file_data
*sfd
= shm_file_data(file
);
540 return sfd
->vm_ops
->fault(vmf
);
543 static int shm_may_split(struct vm_area_struct
*vma
, unsigned long addr
)
545 struct file
*file
= vma
->vm_file
;
546 struct shm_file_data
*sfd
= shm_file_data(file
);
548 if (sfd
->vm_ops
->may_split
)
549 return sfd
->vm_ops
->may_split(vma
, addr
);
554 static unsigned long shm_pagesize(struct vm_area_struct
*vma
)
556 struct file
*file
= vma
->vm_file
;
557 struct shm_file_data
*sfd
= shm_file_data(file
);
559 if (sfd
->vm_ops
->pagesize
)
560 return sfd
->vm_ops
->pagesize(vma
);
566 static int shm_set_policy(struct vm_area_struct
*vma
, struct mempolicy
*mpol
)
568 struct shm_file_data
*sfd
= shm_file_data(vma
->vm_file
);
571 if (sfd
->vm_ops
->set_policy
)
572 err
= sfd
->vm_ops
->set_policy(vma
, mpol
);
576 static struct mempolicy
*shm_get_policy(struct vm_area_struct
*vma
,
577 unsigned long addr
, pgoff_t
*ilx
)
579 struct shm_file_data
*sfd
= shm_file_data(vma
->vm_file
);
580 struct mempolicy
*mpol
= vma
->vm_policy
;
582 if (sfd
->vm_ops
->get_policy
)
583 mpol
= sfd
->vm_ops
->get_policy(vma
, addr
, ilx
);
588 static int shm_mmap(struct file
*file
, struct vm_area_struct
*vma
)
590 struct shm_file_data
*sfd
= shm_file_data(file
);
594 * In case of remap_file_pages() emulation, the file can represent an
595 * IPC ID that was removed, and possibly even reused by another shm
596 * segment already. Propagate this case as an error to caller.
598 ret
= __shm_open(sfd
);
602 ret
= call_mmap(sfd
->file
, vma
);
607 sfd
->vm_ops
= vma
->vm_ops
;
609 WARN_ON(!sfd
->vm_ops
->fault
);
611 vma
->vm_ops
= &shm_vm_ops
;
615 static int shm_release(struct inode
*ino
, struct file
*file
)
617 struct shm_file_data
*sfd
= shm_file_data(file
);
621 shm_file_data(file
) = NULL
;
626 static int shm_fsync(struct file
*file
, loff_t start
, loff_t end
, int datasync
)
628 struct shm_file_data
*sfd
= shm_file_data(file
);
630 if (!sfd
->file
->f_op
->fsync
)
632 return sfd
->file
->f_op
->fsync(sfd
->file
, start
, end
, datasync
);
635 static long shm_fallocate(struct file
*file
, int mode
, loff_t offset
,
638 struct shm_file_data
*sfd
= shm_file_data(file
);
640 if (!sfd
->file
->f_op
->fallocate
)
642 return sfd
->file
->f_op
->fallocate(file
, mode
, offset
, len
);
645 static unsigned long shm_get_unmapped_area(struct file
*file
,
646 unsigned long addr
, unsigned long len
, unsigned long pgoff
,
649 struct shm_file_data
*sfd
= shm_file_data(file
);
651 return sfd
->file
->f_op
->get_unmapped_area(sfd
->file
, addr
, len
,
655 static const struct file_operations shm_file_operations
= {
658 .release
= shm_release
,
659 .get_unmapped_area
= shm_get_unmapped_area
,
660 .llseek
= noop_llseek
,
661 .fallocate
= shm_fallocate
,
665 * shm_file_operations_huge is now identical to shm_file_operations,
666 * but we keep it distinct for the sake of is_file_shm_hugepages().
668 static const struct file_operations shm_file_operations_huge
= {
671 .release
= shm_release
,
672 .get_unmapped_area
= shm_get_unmapped_area
,
673 .llseek
= noop_llseek
,
674 .fallocate
= shm_fallocate
,
677 bool is_file_shm_hugepages(struct file
*file
)
679 return file
->f_op
== &shm_file_operations_huge
;
682 static const struct vm_operations_struct shm_vm_ops
= {
683 .open
= shm_open
, /* callback for a new vm-area open */
684 .close
= shm_close
, /* callback for when the vm-area is released */
686 .may_split
= shm_may_split
,
687 .pagesize
= shm_pagesize
,
688 #if defined(CONFIG_NUMA)
689 .set_policy
= shm_set_policy
,
690 .get_policy
= shm_get_policy
,
695 * newseg - Create a new shared memory segment
697 * @params: ptr to the structure that contains key, size and shmflg
699 * Called with shm_ids.rwsem held as a writer.
701 static int newseg(struct ipc_namespace
*ns
, struct ipc_params
*params
)
703 key_t key
= params
->key
;
704 int shmflg
= params
->flg
;
705 size_t size
= params
->u
.size
;
707 struct shmid_kernel
*shp
;
708 size_t numpages
= (size
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
711 vm_flags_t acctflag
= 0;
713 if (size
< SHMMIN
|| size
> ns
->shm_ctlmax
)
716 if (numpages
<< PAGE_SHIFT
< size
)
719 if (ns
->shm_tot
+ numpages
< ns
->shm_tot
||
720 ns
->shm_tot
+ numpages
> ns
->shm_ctlall
)
723 shp
= kmalloc(sizeof(*shp
), GFP_KERNEL_ACCOUNT
);
727 shp
->shm_perm
.key
= key
;
728 shp
->shm_perm
.mode
= (shmflg
& S_IRWXUGO
);
729 shp
->mlock_ucounts
= NULL
;
731 shp
->shm_perm
.security
= NULL
;
732 error
= security_shm_alloc(&shp
->shm_perm
);
738 sprintf(name
, "SYSV%08x", key
);
739 if (shmflg
& SHM_HUGETLB
) {
743 hs
= hstate_sizelog((shmflg
>> SHM_HUGE_SHIFT
) & SHM_HUGE_MASK
);
748 hugesize
= ALIGN(size
, huge_page_size(hs
));
750 /* hugetlb_file_setup applies strict accounting */
751 if (shmflg
& SHM_NORESERVE
)
752 acctflag
= VM_NORESERVE
;
753 file
= hugetlb_file_setup(name
, hugesize
, acctflag
,
754 HUGETLB_SHMFS_INODE
, (shmflg
>> SHM_HUGE_SHIFT
) & SHM_HUGE_MASK
);
757 * Do not allow no accounting for OVERCOMMIT_NEVER, even
760 if ((shmflg
& SHM_NORESERVE
) &&
761 sysctl_overcommit_memory
!= OVERCOMMIT_NEVER
)
762 acctflag
= VM_NORESERVE
;
763 file
= shmem_kernel_file_setup(name
, size
, acctflag
);
765 error
= PTR_ERR(file
);
769 shp
->shm_cprid
= get_pid(task_tgid(current
));
770 shp
->shm_lprid
= NULL
;
771 shp
->shm_atim
= shp
->shm_dtim
= 0;
772 shp
->shm_ctim
= ktime_get_real_seconds();
773 shp
->shm_segsz
= size
;
775 shp
->shm_file
= file
;
776 shp
->shm_creator
= current
;
778 /* ipc_addid() locks shp upon success. */
779 error
= ipc_addid(&shm_ids(ns
), &shp
->shm_perm
, ns
->shm_ctlmni
);
786 list_add(&shp
->shm_clist
, ¤t
->sysvshm
.shm_clist
);
787 task_unlock(current
);
790 * shmid gets reported as "inode#" in /proc/pid/maps.
791 * proc-ps tools use this. Changing this will break them.
793 file_inode(file
)->i_ino
= shp
->shm_perm
.id
;
795 ns
->shm_tot
+= numpages
;
796 error
= shp
->shm_perm
.id
;
798 ipc_unlock_object(&shp
->shm_perm
);
803 ipc_update_pid(&shp
->shm_cprid
, NULL
);
804 ipc_update_pid(&shp
->shm_lprid
, NULL
);
806 ipc_rcu_putref(&shp
->shm_perm
, shm_rcu_free
);
809 call_rcu(&shp
->shm_perm
.rcu
, shm_rcu_free
);
814 * Called with shm_ids.rwsem and ipcp locked.
816 static int shm_more_checks(struct kern_ipc_perm
*ipcp
, struct ipc_params
*params
)
818 struct shmid_kernel
*shp
;
820 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
821 if (shp
->shm_segsz
< params
->u
.size
)
827 long ksys_shmget(key_t key
, size_t size
, int shmflg
)
829 struct ipc_namespace
*ns
;
830 static const struct ipc_ops shm_ops
= {
832 .associate
= security_shm_associate
,
833 .more_checks
= shm_more_checks
,
835 struct ipc_params shm_params
;
837 ns
= current
->nsproxy
->ipc_ns
;
839 shm_params
.key
= key
;
840 shm_params
.flg
= shmflg
;
841 shm_params
.u
.size
= size
;
843 return ipcget(ns
, &shm_ids(ns
), &shm_ops
, &shm_params
);
846 SYSCALL_DEFINE3(shmget
, key_t
, key
, size_t, size
, int, shmflg
)
848 return ksys_shmget(key
, size
, shmflg
);
851 static inline unsigned long copy_shmid_to_user(void __user
*buf
, struct shmid64_ds
*in
, int version
)
855 return copy_to_user(buf
, in
, sizeof(*in
));
860 memset(&out
, 0, sizeof(out
));
861 ipc64_perm_to_ipc_perm(&in
->shm_perm
, &out
.shm_perm
);
862 out
.shm_segsz
= in
->shm_segsz
;
863 out
.shm_atime
= in
->shm_atime
;
864 out
.shm_dtime
= in
->shm_dtime
;
865 out
.shm_ctime
= in
->shm_ctime
;
866 out
.shm_cpid
= in
->shm_cpid
;
867 out
.shm_lpid
= in
->shm_lpid
;
868 out
.shm_nattch
= in
->shm_nattch
;
870 return copy_to_user(buf
, &out
, sizeof(out
));
877 static inline unsigned long
878 copy_shmid_from_user(struct shmid64_ds
*out
, void __user
*buf
, int version
)
882 if (copy_from_user(out
, buf
, sizeof(*out
)))
887 struct shmid_ds tbuf_old
;
889 if (copy_from_user(&tbuf_old
, buf
, sizeof(tbuf_old
)))
892 out
->shm_perm
.uid
= tbuf_old
.shm_perm
.uid
;
893 out
->shm_perm
.gid
= tbuf_old
.shm_perm
.gid
;
894 out
->shm_perm
.mode
= tbuf_old
.shm_perm
.mode
;
903 static inline unsigned long copy_shminfo_to_user(void __user
*buf
, struct shminfo64
*in
, int version
)
907 return copy_to_user(buf
, in
, sizeof(*in
));
912 if (in
->shmmax
> INT_MAX
)
913 out
.shmmax
= INT_MAX
;
915 out
.shmmax
= (int)in
->shmmax
;
917 out
.shmmin
= in
->shmmin
;
918 out
.shmmni
= in
->shmmni
;
919 out
.shmseg
= in
->shmseg
;
920 out
.shmall
= in
->shmall
;
922 return copy_to_user(buf
, &out
, sizeof(out
));
930 * Calculate and add used RSS and swap pages of a shm.
931 * Called with shm_ids.rwsem held as a reader
933 static void shm_add_rss_swap(struct shmid_kernel
*shp
,
934 unsigned long *rss_add
, unsigned long *swp_add
)
938 inode
= file_inode(shp
->shm_file
);
940 if (is_file_hugepages(shp
->shm_file
)) {
941 struct address_space
*mapping
= inode
->i_mapping
;
942 struct hstate
*h
= hstate_file(shp
->shm_file
);
943 *rss_add
+= pages_per_huge_page(h
) * mapping
->nrpages
;
946 struct shmem_inode_info
*info
= SHMEM_I(inode
);
948 spin_lock_irq(&info
->lock
);
949 *rss_add
+= inode
->i_mapping
->nrpages
;
950 *swp_add
+= info
->swapped
;
951 spin_unlock_irq(&info
->lock
);
953 *rss_add
+= inode
->i_mapping
->nrpages
;
959 * Called with shm_ids.rwsem held as a reader
961 static void shm_get_stat(struct ipc_namespace
*ns
, unsigned long *rss
,
970 in_use
= shm_ids(ns
).in_use
;
972 for (total
= 0, next_id
= 0; total
< in_use
; next_id
++) {
973 struct kern_ipc_perm
*ipc
;
974 struct shmid_kernel
*shp
;
976 ipc
= idr_find(&shm_ids(ns
).ipcs_idr
, next_id
);
979 shp
= container_of(ipc
, struct shmid_kernel
, shm_perm
);
981 shm_add_rss_swap(shp
, rss
, swp
);
988 * This function handles some shmctl commands which require the rwsem
989 * to be held in write mode.
990 * NOTE: no locks must be held, the rwsem is taken inside this function.
992 static int shmctl_down(struct ipc_namespace
*ns
, int shmid
, int cmd
,
993 struct shmid64_ds
*shmid64
)
995 struct kern_ipc_perm
*ipcp
;
996 struct shmid_kernel
*shp
;
999 down_write(&shm_ids(ns
).rwsem
);
1002 ipcp
= ipcctl_obtain_check(ns
, &shm_ids(ns
), shmid
, cmd
,
1003 &shmid64
->shm_perm
, 0);
1005 err
= PTR_ERR(ipcp
);
1009 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
1011 err
= security_shm_shmctl(&shp
->shm_perm
, cmd
);
1017 ipc_lock_object(&shp
->shm_perm
);
1018 /* do_shm_rmid unlocks the ipc object and rcu */
1019 do_shm_rmid(ns
, ipcp
);
1022 ipc_lock_object(&shp
->shm_perm
);
1023 err
= ipc_update_perm(&shmid64
->shm_perm
, ipcp
);
1026 shp
->shm_ctim
= ktime_get_real_seconds();
1034 ipc_unlock_object(&shp
->shm_perm
);
1038 up_write(&shm_ids(ns
).rwsem
);
1042 static int shmctl_ipc_info(struct ipc_namespace
*ns
,
1043 struct shminfo64
*shminfo
)
1045 int err
= security_shm_shmctl(NULL
, IPC_INFO
);
1047 memset(shminfo
, 0, sizeof(*shminfo
));
1048 shminfo
->shmmni
= shminfo
->shmseg
= ns
->shm_ctlmni
;
1049 shminfo
->shmmax
= ns
->shm_ctlmax
;
1050 shminfo
->shmall
= ns
->shm_ctlall
;
1051 shminfo
->shmmin
= SHMMIN
;
1052 down_read(&shm_ids(ns
).rwsem
);
1053 err
= ipc_get_maxidx(&shm_ids(ns
));
1054 up_read(&shm_ids(ns
).rwsem
);
1061 static int shmctl_shm_info(struct ipc_namespace
*ns
,
1062 struct shm_info
*shm_info
)
1064 int err
= security_shm_shmctl(NULL
, SHM_INFO
);
1066 memset(shm_info
, 0, sizeof(*shm_info
));
1067 down_read(&shm_ids(ns
).rwsem
);
1068 shm_info
->used_ids
= shm_ids(ns
).in_use
;
1069 shm_get_stat(ns
, &shm_info
->shm_rss
, &shm_info
->shm_swp
);
1070 shm_info
->shm_tot
= ns
->shm_tot
;
1071 shm_info
->swap_attempts
= 0;
1072 shm_info
->swap_successes
= 0;
1073 err
= ipc_get_maxidx(&shm_ids(ns
));
1074 up_read(&shm_ids(ns
).rwsem
);
1081 static int shmctl_stat(struct ipc_namespace
*ns
, int shmid
,
1082 int cmd
, struct shmid64_ds
*tbuf
)
1084 struct shmid_kernel
*shp
;
1087 memset(tbuf
, 0, sizeof(*tbuf
));
1090 if (cmd
== SHM_STAT
|| cmd
== SHM_STAT_ANY
) {
1091 shp
= shm_obtain_object(ns
, shmid
);
1096 } else { /* IPC_STAT */
1097 shp
= shm_obtain_object_check(ns
, shmid
);
1105 * Semantically SHM_STAT_ANY ought to be identical to
1106 * that functionality provided by the /proc/sysvipc/
1107 * interface. As such, only audit these calls and
1108 * do not do traditional S_IRUGO permission checks on
1111 if (cmd
== SHM_STAT_ANY
)
1112 audit_ipc_obj(&shp
->shm_perm
);
1115 if (ipcperms(ns
, &shp
->shm_perm
, S_IRUGO
))
1119 err
= security_shm_shmctl(&shp
->shm_perm
, cmd
);
1123 ipc_lock_object(&shp
->shm_perm
);
1125 if (!ipc_valid_object(&shp
->shm_perm
)) {
1126 ipc_unlock_object(&shp
->shm_perm
);
1131 kernel_to_ipc64_perm(&shp
->shm_perm
, &tbuf
->shm_perm
);
1132 tbuf
->shm_segsz
= shp
->shm_segsz
;
1133 tbuf
->shm_atime
= shp
->shm_atim
;
1134 tbuf
->shm_dtime
= shp
->shm_dtim
;
1135 tbuf
->shm_ctime
= shp
->shm_ctim
;
1136 #ifndef CONFIG_64BIT
1137 tbuf
->shm_atime_high
= shp
->shm_atim
>> 32;
1138 tbuf
->shm_dtime_high
= shp
->shm_dtim
>> 32;
1139 tbuf
->shm_ctime_high
= shp
->shm_ctim
>> 32;
1141 tbuf
->shm_cpid
= pid_vnr(shp
->shm_cprid
);
1142 tbuf
->shm_lpid
= pid_vnr(shp
->shm_lprid
);
1143 tbuf
->shm_nattch
= shp
->shm_nattch
;
1145 if (cmd
== IPC_STAT
) {
1147 * As defined in SUS:
1148 * Return 0 on success
1153 * SHM_STAT and SHM_STAT_ANY (both Linux specific)
1154 * Return the full id, including the sequence number
1156 err
= shp
->shm_perm
.id
;
1159 ipc_unlock_object(&shp
->shm_perm
);
1165 static int shmctl_do_lock(struct ipc_namespace
*ns
, int shmid
, int cmd
)
1167 struct shmid_kernel
*shp
;
1168 struct file
*shm_file
;
1172 shp
= shm_obtain_object_check(ns
, shmid
);
1178 audit_ipc_obj(&(shp
->shm_perm
));
1179 err
= security_shm_shmctl(&shp
->shm_perm
, cmd
);
1183 ipc_lock_object(&shp
->shm_perm
);
1185 /* check if shm_destroy() is tearing down shp */
1186 if (!ipc_valid_object(&shp
->shm_perm
)) {
1191 if (!ns_capable(ns
->user_ns
, CAP_IPC_LOCK
)) {
1192 kuid_t euid
= current_euid();
1194 if (!uid_eq(euid
, shp
->shm_perm
.uid
) &&
1195 !uid_eq(euid
, shp
->shm_perm
.cuid
)) {
1199 if (cmd
== SHM_LOCK
&& !rlimit(RLIMIT_MEMLOCK
)) {
1205 shm_file
= shp
->shm_file
;
1206 if (is_file_hugepages(shm_file
))
1209 if (cmd
== SHM_LOCK
) {
1210 struct ucounts
*ucounts
= current_ucounts();
1212 err
= shmem_lock(shm_file
, 1, ucounts
);
1213 if (!err
&& !(shp
->shm_perm
.mode
& SHM_LOCKED
)) {
1214 shp
->shm_perm
.mode
|= SHM_LOCKED
;
1215 shp
->mlock_ucounts
= ucounts
;
1221 if (!(shp
->shm_perm
.mode
& SHM_LOCKED
))
1223 shmem_lock(shm_file
, 0, shp
->mlock_ucounts
);
1224 shp
->shm_perm
.mode
&= ~SHM_LOCKED
;
1225 shp
->mlock_ucounts
= NULL
;
1227 ipc_unlock_object(&shp
->shm_perm
);
1229 shmem_unlock_mapping(shm_file
->f_mapping
);
1235 ipc_unlock_object(&shp
->shm_perm
);
1241 static long ksys_shmctl(int shmid
, int cmd
, struct shmid_ds __user
*buf
, int version
)
1244 struct ipc_namespace
*ns
;
1245 struct shmid64_ds sem64
;
1247 if (cmd
< 0 || shmid
< 0)
1250 ns
= current
->nsproxy
->ipc_ns
;
1254 struct shminfo64 shminfo
;
1255 err
= shmctl_ipc_info(ns
, &shminfo
);
1258 if (copy_shminfo_to_user(buf
, &shminfo
, version
))
1263 struct shm_info shm_info
;
1264 err
= shmctl_shm_info(ns
, &shm_info
);
1267 if (copy_to_user(buf
, &shm_info
, sizeof(shm_info
)))
1274 err
= shmctl_stat(ns
, shmid
, cmd
, &sem64
);
1277 if (copy_shmid_to_user(buf
, &sem64
, version
))
1282 if (copy_shmid_from_user(&sem64
, buf
, version
))
1286 return shmctl_down(ns
, shmid
, cmd
, &sem64
);
1289 return shmctl_do_lock(ns
, shmid
, cmd
);
1295 SYSCALL_DEFINE3(shmctl
, int, shmid
, int, cmd
, struct shmid_ds __user
*, buf
)
1297 return ksys_shmctl(shmid
, cmd
, buf
, IPC_64
);
1300 #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
1301 long ksys_old_shmctl(int shmid
, int cmd
, struct shmid_ds __user
*buf
)
1303 int version
= ipc_parse_version(&cmd
);
1305 return ksys_shmctl(shmid
, cmd
, buf
, version
);
1308 SYSCALL_DEFINE3(old_shmctl
, int, shmid
, int, cmd
, struct shmid_ds __user
*, buf
)
1310 return ksys_old_shmctl(shmid
, cmd
, buf
);
1314 #ifdef CONFIG_COMPAT
1316 struct compat_shmid_ds
{
1317 struct compat_ipc_perm shm_perm
;
1319 old_time32_t shm_atime
;
1320 old_time32_t shm_dtime
;
1321 old_time32_t shm_ctime
;
1322 compat_ipc_pid_t shm_cpid
;
1323 compat_ipc_pid_t shm_lpid
;
1324 unsigned short shm_nattch
;
1325 unsigned short shm_unused
;
1326 compat_uptr_t shm_unused2
;
1327 compat_uptr_t shm_unused3
;
1330 struct compat_shminfo64
{
1331 compat_ulong_t shmmax
;
1332 compat_ulong_t shmmin
;
1333 compat_ulong_t shmmni
;
1334 compat_ulong_t shmseg
;
1335 compat_ulong_t shmall
;
1336 compat_ulong_t __unused1
;
1337 compat_ulong_t __unused2
;
1338 compat_ulong_t __unused3
;
1339 compat_ulong_t __unused4
;
1342 struct compat_shm_info
{
1343 compat_int_t used_ids
;
1344 compat_ulong_t shm_tot
, shm_rss
, shm_swp
;
1345 compat_ulong_t swap_attempts
, swap_successes
;
1348 static int copy_compat_shminfo_to_user(void __user
*buf
, struct shminfo64
*in
,
1351 if (in
->shmmax
> INT_MAX
)
1352 in
->shmmax
= INT_MAX
;
1353 if (version
== IPC_64
) {
1354 struct compat_shminfo64 info
;
1355 memset(&info
, 0, sizeof(info
));
1356 info
.shmmax
= in
->shmmax
;
1357 info
.shmmin
= in
->shmmin
;
1358 info
.shmmni
= in
->shmmni
;
1359 info
.shmseg
= in
->shmseg
;
1360 info
.shmall
= in
->shmall
;
1361 return copy_to_user(buf
, &info
, sizeof(info
));
1363 struct shminfo info
;
1364 memset(&info
, 0, sizeof(info
));
1365 info
.shmmax
= in
->shmmax
;
1366 info
.shmmin
= in
->shmmin
;
1367 info
.shmmni
= in
->shmmni
;
1368 info
.shmseg
= in
->shmseg
;
1369 info
.shmall
= in
->shmall
;
1370 return copy_to_user(buf
, &info
, sizeof(info
));
1374 static int put_compat_shm_info(struct shm_info
*ip
,
1375 struct compat_shm_info __user
*uip
)
1377 struct compat_shm_info info
;
1379 memset(&info
, 0, sizeof(info
));
1380 info
.used_ids
= ip
->used_ids
;
1381 info
.shm_tot
= ip
->shm_tot
;
1382 info
.shm_rss
= ip
->shm_rss
;
1383 info
.shm_swp
= ip
->shm_swp
;
1384 info
.swap_attempts
= ip
->swap_attempts
;
1385 info
.swap_successes
= ip
->swap_successes
;
1386 return copy_to_user(uip
, &info
, sizeof(info
));
1389 static int copy_compat_shmid_to_user(void __user
*buf
, struct shmid64_ds
*in
,
1392 if (version
== IPC_64
) {
1393 struct compat_shmid64_ds v
;
1394 memset(&v
, 0, sizeof(v
));
1395 to_compat_ipc64_perm(&v
.shm_perm
, &in
->shm_perm
);
1396 v
.shm_atime
= lower_32_bits(in
->shm_atime
);
1397 v
.shm_atime_high
= upper_32_bits(in
->shm_atime
);
1398 v
.shm_dtime
= lower_32_bits(in
->shm_dtime
);
1399 v
.shm_dtime_high
= upper_32_bits(in
->shm_dtime
);
1400 v
.shm_ctime
= lower_32_bits(in
->shm_ctime
);
1401 v
.shm_ctime_high
= upper_32_bits(in
->shm_ctime
);
1402 v
.shm_segsz
= in
->shm_segsz
;
1403 v
.shm_nattch
= in
->shm_nattch
;
1404 v
.shm_cpid
= in
->shm_cpid
;
1405 v
.shm_lpid
= in
->shm_lpid
;
1406 return copy_to_user(buf
, &v
, sizeof(v
));
1408 struct compat_shmid_ds v
;
1409 memset(&v
, 0, sizeof(v
));
1410 to_compat_ipc_perm(&v
.shm_perm
, &in
->shm_perm
);
1411 v
.shm_perm
.key
= in
->shm_perm
.key
;
1412 v
.shm_atime
= in
->shm_atime
;
1413 v
.shm_dtime
= in
->shm_dtime
;
1414 v
.shm_ctime
= in
->shm_ctime
;
1415 v
.shm_segsz
= in
->shm_segsz
;
1416 v
.shm_nattch
= in
->shm_nattch
;
1417 v
.shm_cpid
= in
->shm_cpid
;
1418 v
.shm_lpid
= in
->shm_lpid
;
1419 return copy_to_user(buf
, &v
, sizeof(v
));
1423 static int copy_compat_shmid_from_user(struct shmid64_ds
*out
, void __user
*buf
,
1426 memset(out
, 0, sizeof(*out
));
1427 if (version
== IPC_64
) {
1428 struct compat_shmid64_ds __user
*p
= buf
;
1429 return get_compat_ipc64_perm(&out
->shm_perm
, &p
->shm_perm
);
1431 struct compat_shmid_ds __user
*p
= buf
;
1432 return get_compat_ipc_perm(&out
->shm_perm
, &p
->shm_perm
);
1436 static long compat_ksys_shmctl(int shmid
, int cmd
, void __user
*uptr
, int version
)
1438 struct ipc_namespace
*ns
;
1439 struct shmid64_ds sem64
;
1442 ns
= current
->nsproxy
->ipc_ns
;
1444 if (cmd
< 0 || shmid
< 0)
1449 struct shminfo64 shminfo
;
1450 err
= shmctl_ipc_info(ns
, &shminfo
);
1453 if (copy_compat_shminfo_to_user(uptr
, &shminfo
, version
))
1458 struct shm_info shm_info
;
1459 err
= shmctl_shm_info(ns
, &shm_info
);
1462 if (put_compat_shm_info(&shm_info
, uptr
))
1469 err
= shmctl_stat(ns
, shmid
, cmd
, &sem64
);
1472 if (copy_compat_shmid_to_user(uptr
, &sem64
, version
))
1477 if (copy_compat_shmid_from_user(&sem64
, uptr
, version
))
1481 return shmctl_down(ns
, shmid
, cmd
, &sem64
);
1484 return shmctl_do_lock(ns
, shmid
, cmd
);
1491 COMPAT_SYSCALL_DEFINE3(shmctl
, int, shmid
, int, cmd
, void __user
*, uptr
)
1493 return compat_ksys_shmctl(shmid
, cmd
, uptr
, IPC_64
);
1496 #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
1497 long compat_ksys_old_shmctl(int shmid
, int cmd
, void __user
*uptr
)
1499 int version
= compat_ipc_parse_version(&cmd
);
1501 return compat_ksys_shmctl(shmid
, cmd
, uptr
, version
);
1504 COMPAT_SYSCALL_DEFINE3(old_shmctl
, int, shmid
, int, cmd
, void __user
*, uptr
)
1506 return compat_ksys_old_shmctl(shmid
, cmd
, uptr
);
1512 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1514 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1515 * "raddr" thing points to kernel space, and there has to be a wrapper around
1518 long do_shmat(int shmid
, char __user
*shmaddr
, int shmflg
,
1519 ulong
*raddr
, unsigned long shmlba
)
1521 struct shmid_kernel
*shp
;
1522 unsigned long addr
= (unsigned long)shmaddr
;
1524 struct file
*file
, *base
;
1526 unsigned long flags
= MAP_SHARED
;
1529 struct ipc_namespace
*ns
;
1530 struct shm_file_data
*sfd
;
1532 unsigned long populate
= 0;
1539 if (addr
& (shmlba
- 1)) {
1540 if (shmflg
& SHM_RND
) {
1541 addr
&= ~(shmlba
- 1); /* round down */
1544 * Ensure that the round-down is non-nil
1545 * when remapping. This can happen for
1546 * cases when addr < shmlba.
1548 if (!addr
&& (shmflg
& SHM_REMAP
))
1551 #ifndef __ARCH_FORCE_SHMLBA
1552 if (addr
& ~PAGE_MASK
)
1558 } else if ((shmflg
& SHM_REMAP
))
1561 if (shmflg
& SHM_RDONLY
) {
1566 prot
= PROT_READ
| PROT_WRITE
;
1567 acc_mode
= S_IRUGO
| S_IWUGO
;
1570 if (shmflg
& SHM_EXEC
) {
1572 acc_mode
|= S_IXUGO
;
1576 * We cannot rely on the fs check since SYSV IPC does have an
1577 * additional creator id...
1579 ns
= current
->nsproxy
->ipc_ns
;
1581 shp
= shm_obtain_object_check(ns
, shmid
);
1588 if (ipcperms(ns
, &shp
->shm_perm
, acc_mode
))
1591 err
= security_shm_shmat(&shp
->shm_perm
, shmaddr
, shmflg
);
1595 ipc_lock_object(&shp
->shm_perm
);
1597 /* check if shm_destroy() is tearing down shp */
1598 if (!ipc_valid_object(&shp
->shm_perm
)) {
1599 ipc_unlock_object(&shp
->shm_perm
);
1605 * We need to take a reference to the real shm file to prevent the
1606 * pointer from becoming stale in cases where the lifetime of the outer
1607 * file extends beyond that of the shm segment. It's not usually
1608 * possible, but it can happen during remap_file_pages() emulation as
1609 * that unmaps the memory, then does ->mmap() via file reference only.
1610 * We'll deny the ->mmap() if the shm segment was since removed, but to
1611 * detect shm ID reuse we need to compare the file pointers.
1613 base
= get_file(shp
->shm_file
);
1615 size
= i_size_read(file_inode(base
));
1616 ipc_unlock_object(&shp
->shm_perm
);
1620 sfd
= kzalloc(sizeof(*sfd
), GFP_KERNEL
);
1626 file
= alloc_file_clone(base
, f_flags
,
1627 is_file_hugepages(base
) ?
1628 &shm_file_operations_huge
:
1629 &shm_file_operations
);
1630 err
= PTR_ERR(file
);
1637 sfd
->id
= shp
->shm_perm
.id
;
1638 sfd
->ns
= get_ipc_ns(ns
);
1641 file
->private_data
= sfd
;
1643 err
= security_mmap_file(file
, prot
, flags
);
1647 if (mmap_write_lock_killable(current
->mm
)) {
1652 if (addr
&& !(shmflg
& SHM_REMAP
)) {
1654 if (addr
+ size
< addr
)
1657 if (find_vma_intersection(current
->mm
, addr
, addr
+ size
))
1661 addr
= do_mmap(file
, addr
, size
, prot
, flags
, 0, 0, &populate
, NULL
);
1664 if (IS_ERR_VALUE(addr
))
1667 mmap_write_unlock(current
->mm
);
1669 mm_populate(addr
, populate
);
1675 down_write(&shm_ids(ns
).rwsem
);
1676 shp
= shm_lock(ns
, shmid
);
1679 if (shm_may_destroy(shp
))
1680 shm_destroy(ns
, shp
);
1683 up_write(&shm_ids(ns
).rwsem
);
1692 SYSCALL_DEFINE3(shmat
, int, shmid
, char __user
*, shmaddr
, int, shmflg
)
1697 err
= do_shmat(shmid
, shmaddr
, shmflg
, &ret
, SHMLBA
);
1700 force_successful_syscall_return();
1704 #ifdef CONFIG_COMPAT
1706 #ifndef COMPAT_SHMLBA
1707 #define COMPAT_SHMLBA SHMLBA
1710 COMPAT_SYSCALL_DEFINE3(shmat
, int, shmid
, compat_uptr_t
, shmaddr
, int, shmflg
)
1715 err
= do_shmat(shmid
, compat_ptr(shmaddr
), shmflg
, &ret
, COMPAT_SHMLBA
);
1718 force_successful_syscall_return();
1724 * detach and kill segment if marked destroyed.
1725 * The work is done in shm_close.
1727 long ksys_shmdt(char __user
*shmaddr
)
1729 struct mm_struct
*mm
= current
->mm
;
1730 struct vm_area_struct
*vma
;
1731 unsigned long addr
= (unsigned long)shmaddr
;
1732 int retval
= -EINVAL
;
1736 VMA_ITERATOR(vmi
, mm
, addr
);
1739 if (addr
& ~PAGE_MASK
)
1742 if (mmap_write_lock_killable(mm
))
1746 * This function tries to be smart and unmap shm segments that
1747 * were modified by partial mlock or munmap calls:
1748 * - It first determines the size of the shm segment that should be
1749 * unmapped: It searches for a vma that is backed by shm and that
1750 * started at address shmaddr. It records it's size and then unmaps
1752 * - Then it unmaps all shm vmas that started at shmaddr and that
1753 * are within the initially determined size and that are from the
1754 * same shm segment from which we determined the size.
1755 * Errors from do_munmap are ignored: the function only fails if
1756 * it's called with invalid parameters or if it's called to unmap
1757 * a part of a vma. Both calls in this function are for full vmas,
1758 * the parameters are directly copied from the vma itself and always
1759 * valid - therefore do_munmap cannot fail. (famous last words?)
1762 * If it had been mremap()'d, the starting address would not
1763 * match the usual checks anyway. So assume all vma's are
1764 * above the starting address given.
1768 for_each_vma(vmi
, vma
) {
1770 * Check if the starting address would match, i.e. it's
1771 * a fragment created by mprotect() and/or munmap(), or it
1772 * otherwise it starts at this address with no hassles.
1774 if ((vma
->vm_ops
== &shm_vm_ops
) &&
1775 (vma
->vm_start
- addr
)/PAGE_SIZE
== vma
->vm_pgoff
) {
1778 * Record the file of the shm segment being
1779 * unmapped. With mremap(), someone could place
1780 * page from another segment but with equal offsets
1781 * in the range we are unmapping.
1783 file
= vma
->vm_file
;
1784 size
= i_size_read(file_inode(vma
->vm_file
));
1785 do_vma_munmap(&vmi
, vma
, vma
->vm_start
, vma
->vm_end
,
1788 * We discovered the size of the shm segment, so
1789 * break out of here and fall through to the next
1790 * loop that uses the size information to stop
1791 * searching for matching vma's.
1794 vma
= vma_next(&vmi
);
1800 * We need look no further than the maximum address a fragment
1801 * could possibly have landed at. Also cast things to loff_t to
1802 * prevent overflows and make comparisons vs. equal-width types.
1804 size
= PAGE_ALIGN(size
);
1805 while (vma
&& (loff_t
)(vma
->vm_end
- addr
) <= size
) {
1806 /* finding a matching vma now does not alter retval */
1807 if ((vma
->vm_ops
== &shm_vm_ops
) &&
1808 ((vma
->vm_start
- addr
)/PAGE_SIZE
== vma
->vm_pgoff
) &&
1809 (vma
->vm_file
== file
)) {
1810 do_vma_munmap(&vmi
, vma
, vma
->vm_start
, vma
->vm_end
,
1814 vma
= vma_next(&vmi
);
1817 #else /* CONFIG_MMU */
1818 vma
= vma_lookup(mm
, addr
);
1819 /* under NOMMU conditions, the exact address to be destroyed must be
1822 if (vma
&& vma
->vm_start
== addr
&& vma
->vm_ops
== &shm_vm_ops
) {
1823 do_munmap(mm
, vma
->vm_start
, vma
->vm_end
- vma
->vm_start
, NULL
);
1829 mmap_write_unlock(mm
);
1833 SYSCALL_DEFINE1(shmdt
, char __user
*, shmaddr
)
1835 return ksys_shmdt(shmaddr
);
1838 #ifdef CONFIG_PROC_FS
1839 static int sysvipc_shm_proc_show(struct seq_file
*s
, void *it
)
1841 struct pid_namespace
*pid_ns
= ipc_seq_pid_ns(s
);
1842 struct user_namespace
*user_ns
= seq_user_ns(s
);
1843 struct kern_ipc_perm
*ipcp
= it
;
1844 struct shmid_kernel
*shp
;
1845 unsigned long rss
= 0, swp
= 0;
1847 shp
= container_of(ipcp
, struct shmid_kernel
, shm_perm
);
1848 shm_add_rss_swap(shp
, &rss
, &swp
);
1850 #if BITS_PER_LONG <= 32
1851 #define SIZE_SPEC "%10lu"
1853 #define SIZE_SPEC "%21lu"
1857 "%10d %10d %4o " SIZE_SPEC
" %5u %5u "
1858 "%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
1859 SIZE_SPEC
" " SIZE_SPEC
"\n",
1864 pid_nr_ns(shp
->shm_cprid
, pid_ns
),
1865 pid_nr_ns(shp
->shm_lprid
, pid_ns
),
1867 from_kuid_munged(user_ns
, shp
->shm_perm
.uid
),
1868 from_kgid_munged(user_ns
, shp
->shm_perm
.gid
),
1869 from_kuid_munged(user_ns
, shp
->shm_perm
.cuid
),
1870 from_kgid_munged(user_ns
, shp
->shm_perm
.cgid
),