3 * Copyright (C) 1992, 1993 Krishna Balasubramanian
4 * Many improvements/fixes by Bruno Haible.
5 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
6 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
8 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
9 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
10 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
11 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
12 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
13 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
14 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
16 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
21 * Pavel Emelianov <xemul@openvz.org>
23 * Better ipc lock (kern_ipc_perm.lock) handling
24 * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
27 #include <linux/slab.h>
29 #include <linux/hugetlb.h>
30 #include <linux/shm.h>
31 #include <linux/init.h>
32 #include <linux/file.h>
33 #include <linux/mman.h>
34 #include <linux/shmem_fs.h>
35 #include <linux/security.h>
36 #include <linux/syscalls.h>
37 #include <linux/audit.h>
38 #include <linux/capability.h>
39 #include <linux/ptrace.h>
40 #include <linux/seq_file.h>
41 #include <linux/rwsem.h>
42 #include <linux/nsproxy.h>
43 #include <linux/mount.h>
44 #include <linux/ipc_namespace.h>
46 #include <asm/uaccess.h>
50 struct shm_file_data {
52 struct ipc_namespace *ns;
54 const struct vm_operations_struct *vm_ops;
57 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
59 static const struct file_operations shm_file_operations;
60 static const struct vm_operations_struct shm_vm_ops;
62 #define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
64 #define shm_unlock(shp) \
65 ipc_unlock(&(shp)->shm_perm)
67 static int newseg(struct ipc_namespace *, struct ipc_params *);
68 static void shm_open(struct vm_area_struct *vma);
69 static void shm_close(struct vm_area_struct *vma);
70 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
72 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
75 void shm_init_ns(struct ipc_namespace *ns)
77 ns->shm_ctlmax = SHMMAX;
78 ns->shm_ctlall = SHMALL;
79 ns->shm_ctlmni = SHMMNI;
80 ns->shm_rmid_forced = 0;
82 ipc_init_ids(&shm_ids(ns));
86 * Called with shm_ids.rwsem (writer) and the shp structure locked.
87 * Only shm_ids.rwsem remains locked on exit.
89 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
91 struct shmid_kernel *shp;
92 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
95 shp->shm_perm.mode |= SHM_DEST;
96 /* Do not find it any more */
97 shp->shm_perm.key = IPC_PRIVATE;
100 shm_destroy(ns, shp);
104 void shm_exit_ns(struct ipc_namespace *ns)
106 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
107 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
111 static int __init ipc_ns_init(void)
113 shm_init_ns(&init_ipc_ns);
117 pure_initcall(ipc_ns_init);
119 void __init shm_init (void)
121 ipc_init_proc_interface("sysvipc/shm",
122 #if BITS_PER_LONG <= 32
123 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
125 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
127 IPC_SHM_IDS, sysvipc_shm_proc_show);
130 static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
132 struct kern_ipc_perm *ipcp = ipc_obtain_object(&shm_ids(ns), id);
135 return ERR_CAST(ipcp);
137 return container_of(ipcp, struct shmid_kernel, shm_perm);
140 static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
142 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
145 return ERR_CAST(ipcp);
147 return container_of(ipcp, struct shmid_kernel, shm_perm);
151 * shm_lock_(check_) routines are called in the paths where the rwsem
152 * is not necessarily held.
154 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
156 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
159 return (struct shmid_kernel *)ipcp;
161 return container_of(ipcp, struct shmid_kernel, shm_perm);
164 static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
167 ipc_lock_object(&ipcp->shm_perm);
170 static void shm_rcu_free(struct rcu_head *head)
172 struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
173 struct shmid_kernel *shp = ipc_rcu_to_struct(p);
175 security_shm_free(shp);
179 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
181 ipc_rmid(&shm_ids(ns), &s->shm_perm);
185 /* This is called by fork, once for every shm attach. */
186 static void shm_open(struct vm_area_struct *vma)
188 struct file *file = vma->vm_file;
189 struct shm_file_data *sfd = shm_file_data(file);
190 struct shmid_kernel *shp;
192 shp = shm_lock(sfd->ns, sfd->id);
194 shp->shm_atim = get_seconds();
195 shp->shm_lprid = task_tgid_vnr(current);
201 * shm_destroy - free the struct shmid_kernel
204 * @shp: struct to free
206 * It has to be called with shp and shm_ids.rwsem (writer) locked,
207 * but returns with shp unlocked and freed.
209 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
211 struct file *shm_file;
213 shm_file = shp->shm_file;
214 shp->shm_file = NULL;
215 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
218 if (!is_file_hugepages(shm_file))
219 shmem_lock(shm_file, 0, shp->mlock_user);
220 else if (shp->mlock_user)
221 user_shm_unlock(file_inode(shm_file)->i_size, shp->mlock_user);
223 ipc_rcu_putref(shp, shm_rcu_free);
227 * shm_may_destroy - identifies whether shm segment should be destroyed now
229 * Returns true if and only if there are no active users of the segment and
230 * one of the following is true:
232 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
234 * 2) sysctl kernel.shm_rmid_forced is set to 1.
236 static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
238 return (shp->shm_nattch == 0) &&
239 (ns->shm_rmid_forced ||
240 (shp->shm_perm.mode & SHM_DEST));
244 * remove the attach descriptor vma.
245 * free memory for segment if it is marked destroyed.
246 * The descriptor has already been removed from the current->mm->mmap list
247 * and will later be kfree()d.
249 static void shm_close(struct vm_area_struct *vma)
251 struct file * file = vma->vm_file;
252 struct shm_file_data *sfd = shm_file_data(file);
253 struct shmid_kernel *shp;
254 struct ipc_namespace *ns = sfd->ns;
256 down_write(&shm_ids(ns).rwsem);
257 /* remove from the list of attaches of the shm segment */
258 shp = shm_lock(ns, sfd->id);
260 shp->shm_lprid = task_tgid_vnr(current);
261 shp->shm_dtim = get_seconds();
263 if (shm_may_destroy(ns, shp))
264 shm_destroy(ns, shp);
267 up_write(&shm_ids(ns).rwsem);
270 /* Called with ns->shm_ids(ns).rwsem locked */
271 static int shm_try_destroy_current(int id, void *p, void *data)
273 struct ipc_namespace *ns = data;
274 struct kern_ipc_perm *ipcp = p;
275 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
277 if (shp->shm_creator != current)
281 * Mark it as orphaned to destroy the segment when
282 * kernel.shm_rmid_forced is changed.
283 * It is noop if the following shm_may_destroy() returns true.
285 shp->shm_creator = NULL;
288 * Don't even try to destroy it. If shm_rmid_forced=0 and IPC_RMID
289 * is not set, it shouldn't be deleted here.
291 if (!ns->shm_rmid_forced)
294 if (shm_may_destroy(ns, shp)) {
295 shm_lock_by_ptr(shp);
296 shm_destroy(ns, shp);
301 /* Called with ns->shm_ids(ns).rwsem locked */
302 static int shm_try_destroy_orphaned(int id, void *p, void *data)
304 struct ipc_namespace *ns = data;
305 struct kern_ipc_perm *ipcp = p;
306 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
309 * We want to destroy segments without users and with already
310 * exit'ed originating process.
312 * As shp->* are changed under rwsem, it's safe to skip shp locking.
314 if (shp->shm_creator != NULL)
317 if (shm_may_destroy(ns, shp)) {
318 shm_lock_by_ptr(shp);
319 shm_destroy(ns, shp);
324 void shm_destroy_orphaned(struct ipc_namespace *ns)
326 down_write(&shm_ids(ns).rwsem);
327 if (shm_ids(ns).in_use)
328 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
329 up_write(&shm_ids(ns).rwsem);
333 void exit_shm(struct task_struct *task)
335 struct ipc_namespace *ns = task->nsproxy->ipc_ns;
337 if (shm_ids(ns).in_use == 0)
340 /* Destroy all already created segments, but not mapped yet */
341 down_write(&shm_ids(ns).rwsem);
342 if (shm_ids(ns).in_use)
343 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
344 up_write(&shm_ids(ns).rwsem);
347 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
349 struct file *file = vma->vm_file;
350 struct shm_file_data *sfd = shm_file_data(file);
352 return sfd->vm_ops->fault(vma, vmf);
356 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
358 struct file *file = vma->vm_file;
359 struct shm_file_data *sfd = shm_file_data(file);
361 if (sfd->vm_ops->set_policy)
362 err = sfd->vm_ops->set_policy(vma, new);
366 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
369 struct file *file = vma->vm_file;
370 struct shm_file_data *sfd = shm_file_data(file);
371 struct mempolicy *pol = NULL;
373 if (sfd->vm_ops->get_policy)
374 pol = sfd->vm_ops->get_policy(vma, addr);
375 else if (vma->vm_policy)
376 pol = vma->vm_policy;
382 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
384 struct shm_file_data *sfd = shm_file_data(file);
387 ret = sfd->file->f_op->mmap(sfd->file, vma);
390 sfd->vm_ops = vma->vm_ops;
392 BUG_ON(!sfd->vm_ops->fault);
394 vma->vm_ops = &shm_vm_ops;
400 static int shm_release(struct inode *ino, struct file *file)
402 struct shm_file_data *sfd = shm_file_data(file);
405 shm_file_data(file) = NULL;
410 static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
412 struct shm_file_data *sfd = shm_file_data(file);
414 if (!sfd->file->f_op->fsync)
416 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
419 static long shm_fallocate(struct file *file, int mode, loff_t offset,
422 struct shm_file_data *sfd = shm_file_data(file);
424 if (!sfd->file->f_op->fallocate)
426 return sfd->file->f_op->fallocate(file, mode, offset, len);
429 static unsigned long shm_get_unmapped_area(struct file *file,
430 unsigned long addr, unsigned long len, unsigned long pgoff,
433 struct shm_file_data *sfd = shm_file_data(file);
434 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
438 static const struct file_operations shm_file_operations = {
441 .release = shm_release,
443 .get_unmapped_area = shm_get_unmapped_area,
445 .llseek = noop_llseek,
446 .fallocate = shm_fallocate,
449 static const struct file_operations shm_file_operations_huge = {
452 .release = shm_release,
453 .get_unmapped_area = shm_get_unmapped_area,
454 .llseek = noop_llseek,
455 .fallocate = shm_fallocate,
458 int is_file_shm_hugepages(struct file *file)
460 return file->f_op == &shm_file_operations_huge;
463 static const struct vm_operations_struct shm_vm_ops = {
464 .open = shm_open, /* callback for a new vm-area open */
465 .close = shm_close, /* callback for when the vm-area is released */
467 #if defined(CONFIG_NUMA)
468 .set_policy = shm_set_policy,
469 .get_policy = shm_get_policy,
474 * newseg - Create a new shared memory segment
476 * @params: ptr to the structure that contains key, size and shmflg
478 * Called with shm_ids.rwsem held as a writer.
481 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
483 key_t key = params->key;
484 int shmflg = params->flg;
485 size_t size = params->u.size;
487 struct shmid_kernel *shp;
488 size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
492 vm_flags_t acctflag = 0;
494 if (size < SHMMIN || size > ns->shm_ctlmax)
497 if (ns->shm_tot + numpages > ns->shm_ctlall)
500 shp = ipc_rcu_alloc(sizeof(*shp));
504 shp->shm_perm.key = key;
505 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
506 shp->mlock_user = NULL;
508 shp->shm_perm.security = NULL;
509 error = security_shm_alloc(shp);
511 ipc_rcu_putref(shp, ipc_rcu_free);
515 sprintf (name, "SYSV%08x", key);
516 if (shmflg & SHM_HUGETLB) {
520 hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
525 hugesize = ALIGN(size, huge_page_size(hs));
527 /* hugetlb_file_setup applies strict accounting */
528 if (shmflg & SHM_NORESERVE)
529 acctflag = VM_NORESERVE;
530 file = hugetlb_file_setup(name, hugesize, acctflag,
531 &shp->mlock_user, HUGETLB_SHMFS_INODE,
532 (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
535 * Do not allow no accounting for OVERCOMMIT_NEVER, even
538 if ((shmflg & SHM_NORESERVE) &&
539 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
540 acctflag = VM_NORESERVE;
541 file = shmem_file_setup(name, size, acctflag);
543 error = PTR_ERR(file);
547 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
553 shp->shm_cprid = task_tgid_vnr(current);
555 shp->shm_atim = shp->shm_dtim = 0;
556 shp->shm_ctim = get_seconds();
557 shp->shm_segsz = size;
559 shp->shm_file = file;
560 shp->shm_creator = current;
563 * shmid gets reported as "inode#" in /proc/pid/maps.
564 * proc-ps tools use this. Changing this will break them.
566 file_inode(file)->i_ino = shp->shm_perm.id;
568 ns->shm_tot += numpages;
569 error = shp->shm_perm.id;
571 ipc_unlock_object(&shp->shm_perm);
576 if (is_file_hugepages(file) && shp->mlock_user)
577 user_shm_unlock(size, shp->mlock_user);
580 ipc_rcu_putref(shp, shm_rcu_free);
585 * Called with shm_ids.rwsem and ipcp locked.
587 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
589 struct shmid_kernel *shp;
591 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
592 return security_shm_associate(shp, shmflg);
596 * Called with shm_ids.rwsem and ipcp locked.
598 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
599 struct ipc_params *params)
601 struct shmid_kernel *shp;
603 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
604 if (shp->shm_segsz < params->u.size)
610 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
612 struct ipc_namespace *ns;
613 struct ipc_ops shm_ops;
614 struct ipc_params shm_params;
616 ns = current->nsproxy->ipc_ns;
618 shm_ops.getnew = newseg;
619 shm_ops.associate = shm_security;
620 shm_ops.more_checks = shm_more_checks;
622 shm_params.key = key;
623 shm_params.flg = shmflg;
624 shm_params.u.size = size;
626 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
629 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
633 return copy_to_user(buf, in, sizeof(*in));
638 memset(&out, 0, sizeof(out));
639 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
640 out.shm_segsz = in->shm_segsz;
641 out.shm_atime = in->shm_atime;
642 out.shm_dtime = in->shm_dtime;
643 out.shm_ctime = in->shm_ctime;
644 out.shm_cpid = in->shm_cpid;
645 out.shm_lpid = in->shm_lpid;
646 out.shm_nattch = in->shm_nattch;
648 return copy_to_user(buf, &out, sizeof(out));
655 static inline unsigned long
656 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
660 if (copy_from_user(out, buf, sizeof(*out)))
665 struct shmid_ds tbuf_old;
667 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
670 out->shm_perm.uid = tbuf_old.shm_perm.uid;
671 out->shm_perm.gid = tbuf_old.shm_perm.gid;
672 out->shm_perm.mode = tbuf_old.shm_perm.mode;
681 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
685 return copy_to_user(buf, in, sizeof(*in));
690 if(in->shmmax > INT_MAX)
691 out.shmmax = INT_MAX;
693 out.shmmax = (int)in->shmmax;
695 out.shmmin = in->shmmin;
696 out.shmmni = in->shmmni;
697 out.shmseg = in->shmseg;
698 out.shmall = in->shmall;
700 return copy_to_user(buf, &out, sizeof(out));
708 * Calculate and add used RSS and swap pages of a shm.
709 * Called with shm_ids.rwsem held as a reader
711 static void shm_add_rss_swap(struct shmid_kernel *shp,
712 unsigned long *rss_add, unsigned long *swp_add)
716 inode = file_inode(shp->shm_file);
718 if (is_file_hugepages(shp->shm_file)) {
719 struct address_space *mapping = inode->i_mapping;
720 struct hstate *h = hstate_file(shp->shm_file);
721 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
724 struct shmem_inode_info *info = SHMEM_I(inode);
725 spin_lock(&info->lock);
726 *rss_add += inode->i_mapping->nrpages;
727 *swp_add += info->swapped;
728 spin_unlock(&info->lock);
730 *rss_add += inode->i_mapping->nrpages;
736 * Called with shm_ids.rwsem held as a reader
738 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
747 in_use = shm_ids(ns).in_use;
749 for (total = 0, next_id = 0; total < in_use; next_id++) {
750 struct kern_ipc_perm *ipc;
751 struct shmid_kernel *shp;
753 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
756 shp = container_of(ipc, struct shmid_kernel, shm_perm);
758 shm_add_rss_swap(shp, rss, swp);
765 * This function handles some shmctl commands which require the rwsem
766 * to be held in write mode.
767 * NOTE: no locks must be held, the rwsem is taken inside this function.
769 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
770 struct shmid_ds __user *buf, int version)
772 struct kern_ipc_perm *ipcp;
773 struct shmid64_ds shmid64;
774 struct shmid_kernel *shp;
777 if (cmd == IPC_SET) {
778 if (copy_shmid_from_user(&shmid64, buf, version))
782 down_write(&shm_ids(ns).rwsem);
785 ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
786 &shmid64.shm_perm, 0);
792 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
794 err = security_shm_shmctl(shp, cmd);
800 ipc_lock_object(&shp->shm_perm);
801 /* do_shm_rmid unlocks the ipc object and rcu */
802 do_shm_rmid(ns, ipcp);
805 ipc_lock_object(&shp->shm_perm);
806 err = ipc_update_perm(&shmid64.shm_perm, ipcp);
809 shp->shm_ctim = get_seconds();
817 ipc_unlock_object(&shp->shm_perm);
821 up_write(&shm_ids(ns).rwsem);
825 static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
826 int cmd, int version, void __user *buf)
829 struct shmid_kernel *shp;
831 /* preliminary security checks for *_INFO */
832 if (cmd == IPC_INFO || cmd == SHM_INFO) {
833 err = security_shm_shmctl(NULL, cmd);
841 struct shminfo64 shminfo;
843 memset(&shminfo, 0, sizeof(shminfo));
844 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
845 shminfo.shmmax = ns->shm_ctlmax;
846 shminfo.shmall = ns->shm_ctlall;
848 shminfo.shmmin = SHMMIN;
849 if(copy_shminfo_to_user (buf, &shminfo, version))
852 down_read(&shm_ids(ns).rwsem);
853 err = ipc_get_maxid(&shm_ids(ns));
854 up_read(&shm_ids(ns).rwsem);
862 struct shm_info shm_info;
864 memset(&shm_info, 0, sizeof(shm_info));
865 down_read(&shm_ids(ns).rwsem);
866 shm_info.used_ids = shm_ids(ns).in_use;
867 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
868 shm_info.shm_tot = ns->shm_tot;
869 shm_info.swap_attempts = 0;
870 shm_info.swap_successes = 0;
871 err = ipc_get_maxid(&shm_ids(ns));
872 up_read(&shm_ids(ns).rwsem);
873 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
878 err = err < 0 ? 0 : err;
884 struct shmid64_ds tbuf;
888 if (cmd == SHM_STAT) {
889 shp = shm_obtain_object(ns, shmid);
894 result = shp->shm_perm.id;
896 shp = shm_obtain_object_check(ns, shmid);
905 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
908 err = security_shm_shmctl(shp, cmd);
912 memset(&tbuf, 0, sizeof(tbuf));
913 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
914 tbuf.shm_segsz = shp->shm_segsz;
915 tbuf.shm_atime = shp->shm_atim;
916 tbuf.shm_dtime = shp->shm_dtim;
917 tbuf.shm_ctime = shp->shm_ctim;
918 tbuf.shm_cpid = shp->shm_cprid;
919 tbuf.shm_lpid = shp->shm_lprid;
920 tbuf.shm_nattch = shp->shm_nattch;
923 if (copy_shmid_to_user(buf, &tbuf, version))
939 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
941 struct shmid_kernel *shp;
943 struct ipc_namespace *ns;
945 if (cmd < 0 || shmid < 0)
948 version = ipc_parse_version(&cmd);
949 ns = current->nsproxy->ipc_ns;
956 return shmctl_nolock(ns, shmid, cmd, version, buf);
959 return shmctl_down(ns, shmid, cmd, buf, version);
963 struct file *shm_file;
966 shp = shm_obtain_object_check(ns, shmid);
972 audit_ipc_obj(&(shp->shm_perm));
973 err = security_shm_shmctl(shp, cmd);
977 ipc_lock_object(&shp->shm_perm);
978 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
979 kuid_t euid = current_euid();
980 if (!uid_eq(euid, shp->shm_perm.uid) &&
981 !uid_eq(euid, shp->shm_perm.cuid)) {
985 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
991 shm_file = shp->shm_file;
993 /* check if shm_destroy() is tearing down shp */
994 if (shm_file == NULL) {
999 if (is_file_hugepages(shm_file))
1002 if (cmd == SHM_LOCK) {
1003 struct user_struct *user = current_user();
1004 err = shmem_lock(shm_file, 1, user);
1005 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1006 shp->shm_perm.mode |= SHM_LOCKED;
1007 shp->mlock_user = user;
1013 if (!(shp->shm_perm.mode & SHM_LOCKED))
1015 shmem_lock(shm_file, 0, shp->mlock_user);
1016 shp->shm_perm.mode &= ~SHM_LOCKED;
1017 shp->mlock_user = NULL;
1019 ipc_unlock_object(&shp->shm_perm);
1021 shmem_unlock_mapping(shm_file->f_mapping);
1031 ipc_unlock_object(&shp->shm_perm);
1038 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1040 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1041 * "raddr" thing points to kernel space, and there has to be a wrapper around
1044 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
1045 unsigned long shmlba)
1047 struct shmid_kernel *shp;
1052 unsigned long flags;
1055 struct ipc_namespace *ns;
1056 struct shm_file_data *sfd;
1059 unsigned long populate = 0;
1064 else if ((addr = (ulong)shmaddr)) {
1065 if (addr & (shmlba - 1)) {
1066 if (shmflg & SHM_RND)
1067 addr &= ~(shmlba - 1); /* round down */
1069 #ifndef __ARCH_FORCE_SHMLBA
1070 if (addr & ~PAGE_MASK)
1074 flags = MAP_SHARED | MAP_FIXED;
1076 if ((shmflg & SHM_REMAP))
1082 if (shmflg & SHM_RDONLY) {
1085 f_mode = FMODE_READ;
1087 prot = PROT_READ | PROT_WRITE;
1088 acc_mode = S_IRUGO | S_IWUGO;
1089 f_mode = FMODE_READ | FMODE_WRITE;
1091 if (shmflg & SHM_EXEC) {
1093 acc_mode |= S_IXUGO;
1097 * We cannot rely on the fs check since SYSV IPC does have an
1098 * additional creator id...
1100 ns = current->nsproxy->ipc_ns;
1102 shp = shm_obtain_object_check(ns, shmid);
1109 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1112 err = security_shm_shmat(shp, shmaddr, shmflg);
1116 ipc_lock_object(&shp->shm_perm);
1118 /* check if shm_destroy() is tearing down shp */
1119 if (shp->shm_file == NULL) {
1120 ipc_unlock_object(&shp->shm_perm);
1125 path = shp->shm_file->f_path;
1128 size = i_size_read(path.dentry->d_inode);
1129 ipc_unlock_object(&shp->shm_perm);
1133 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1139 file = alloc_file(&path, f_mode,
1140 is_file_hugepages(shp->shm_file) ?
1141 &shm_file_operations_huge :
1142 &shm_file_operations);
1143 err = PTR_ERR(file);
1150 file->private_data = sfd;
1151 file->f_mapping = shp->shm_file->f_mapping;
1152 sfd->id = shp->shm_perm.id;
1153 sfd->ns = get_ipc_ns(ns);
1154 sfd->file = shp->shm_file;
1157 err = security_mmap_file(file, prot, flags);
1161 down_write(¤t->mm->mmap_sem);
1162 if (addr && !(shmflg & SHM_REMAP)) {
1164 if (find_vma_intersection(current->mm, addr, addr + size))
1167 * If shm segment goes below stack, make sure there is some
1168 * space left for the stack to grow (at least 4 pages).
1170 if (addr < current->mm->start_stack &&
1171 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1175 addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate);
1178 if (IS_ERR_VALUE(addr))
1181 up_write(¤t->mm->mmap_sem);
1183 mm_populate(addr, populate);
1189 down_write(&shm_ids(ns).rwsem);
1190 shp = shm_lock(ns, shmid);
1191 BUG_ON(IS_ERR(shp));
1193 if (shm_may_destroy(ns, shp))
1194 shm_destroy(ns, shp);
1197 up_write(&shm_ids(ns).rwsem);
1206 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1211 err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1214 force_successful_syscall_return();
1219 * detach and kill segment if marked destroyed.
1220 * The work is done in shm_close.
1222 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1224 struct mm_struct *mm = current->mm;
1225 struct vm_area_struct *vma;
1226 unsigned long addr = (unsigned long)shmaddr;
1227 int retval = -EINVAL;
1230 struct vm_area_struct *next;
1233 if (addr & ~PAGE_MASK)
1236 down_write(&mm->mmap_sem);
1239 * This function tries to be smart and unmap shm segments that
1240 * were modified by partial mlock or munmap calls:
1241 * - It first determines the size of the shm segment that should be
1242 * unmapped: It searches for a vma that is backed by shm and that
1243 * started at address shmaddr. It records it's size and then unmaps
1245 * - Then it unmaps all shm vmas that started at shmaddr and that
1246 * are within the initially determined size.
1247 * Errors from do_munmap are ignored: the function only fails if
1248 * it's called with invalid parameters or if it's called to unmap
1249 * a part of a vma. Both calls in this function are for full vmas,
1250 * the parameters are directly copied from the vma itself and always
1251 * valid - therefore do_munmap cannot fail. (famous last words?)
1254 * If it had been mremap()'d, the starting address would not
1255 * match the usual checks anyway. So assume all vma's are
1256 * above the starting address given.
1258 vma = find_vma(mm, addr);
1262 next = vma->vm_next;
1265 * Check if the starting address would match, i.e. it's
1266 * a fragment created by mprotect() and/or munmap(), or it
1267 * otherwise it starts at this address with no hassles.
1269 if ((vma->vm_ops == &shm_vm_ops) &&
1270 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1273 size = file_inode(vma->vm_file)->i_size;
1274 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1276 * We discovered the size of the shm segment, so
1277 * break out of here and fall through to the next
1278 * loop that uses the size information to stop
1279 * searching for matching vma's.
1289 * We need look no further than the maximum address a fragment
1290 * could possibly have landed at. Also cast things to loff_t to
1291 * prevent overflows and make comparisons vs. equal-width types.
1293 size = PAGE_ALIGN(size);
1294 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1295 next = vma->vm_next;
1297 /* finding a matching vma now does not alter retval */
1298 if ((vma->vm_ops == &shm_vm_ops) &&
1299 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1301 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1305 #else /* CONFIG_MMU */
1306 /* under NOMMU conditions, the exact address to be destroyed must be
1308 if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1309 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1315 up_write(&mm->mmap_sem);
1319 #ifdef CONFIG_PROC_FS
1320 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1322 struct user_namespace *user_ns = seq_user_ns(s);
1323 struct shmid_kernel *shp = it;
1324 unsigned long rss = 0, swp = 0;
1326 shm_add_rss_swap(shp, &rss, &swp);
1328 #if BITS_PER_LONG <= 32
1329 #define SIZE_SPEC "%10lu"
1331 #define SIZE_SPEC "%21lu"
1334 return seq_printf(s,
1335 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1336 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1337 SIZE_SPEC " " SIZE_SPEC "\n",
1345 from_kuid_munged(user_ns, shp->shm_perm.uid),
1346 from_kgid_munged(user_ns, shp->shm_perm.gid),
1347 from_kuid_munged(user_ns, shp->shm_perm.cuid),
1348 from_kgid_munged(user_ns, shp->shm_perm.cgid),