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.rw_mutex (writer) and the shp structure locked.
87 * Only shm_ids.rw_mutex 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 rw_mutex
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 inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
173 struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
176 return (struct shmid_kernel *)ipcp;
178 return container_of(ipcp, struct shmid_kernel, shm_perm);
181 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
183 ipc_rmid(&shm_ids(ns), &s->shm_perm);
187 /* This is called by fork, once for every shm attach. */
188 static void shm_open(struct vm_area_struct *vma)
190 struct file *file = vma->vm_file;
191 struct shm_file_data *sfd = shm_file_data(file);
192 struct shmid_kernel *shp;
194 shp = shm_lock(sfd->ns, sfd->id);
196 shp->shm_atim = get_seconds();
197 shp->shm_lprid = task_tgid_vnr(current);
203 * shm_destroy - free the struct shmid_kernel
206 * @shp: struct to free
208 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
209 * but returns with shp unlocked and freed.
211 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
213 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
216 if (!is_file_hugepages(shp->shm_file))
217 shmem_lock(shp->shm_file, 0, shp->mlock_user);
218 else if (shp->mlock_user)
219 user_shm_unlock(file_inode(shp->shm_file)->i_size,
221 fput (shp->shm_file);
222 security_shm_free(shp);
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).rw_mutex);
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).rw_mutex);
270 /* Called with ns->shm_ids(ns).rw_mutex 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).rw_mutex 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 rw_mutex, 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).rw_mutex);
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).rw_mutex);
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).rw_mutex);
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).rw_mutex);
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.rw_mutex 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);
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 security_shm_free(shp);
586 * Called with shm_ids.rw_mutex and ipcp locked.
588 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
590 struct shmid_kernel *shp;
592 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
593 return security_shm_associate(shp, shmflg);
597 * Called with shm_ids.rw_mutex and ipcp locked.
599 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
600 struct ipc_params *params)
602 struct shmid_kernel *shp;
604 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
605 if (shp->shm_segsz < params->u.size)
611 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
613 struct ipc_namespace *ns;
614 struct ipc_ops shm_ops;
615 struct ipc_params shm_params;
617 ns = current->nsproxy->ipc_ns;
619 shm_ops.getnew = newseg;
620 shm_ops.associate = shm_security;
621 shm_ops.more_checks = shm_more_checks;
623 shm_params.key = key;
624 shm_params.flg = shmflg;
625 shm_params.u.size = size;
627 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
630 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
634 return copy_to_user(buf, in, sizeof(*in));
639 memset(&out, 0, sizeof(out));
640 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
641 out.shm_segsz = in->shm_segsz;
642 out.shm_atime = in->shm_atime;
643 out.shm_dtime = in->shm_dtime;
644 out.shm_ctime = in->shm_ctime;
645 out.shm_cpid = in->shm_cpid;
646 out.shm_lpid = in->shm_lpid;
647 out.shm_nattch = in->shm_nattch;
649 return copy_to_user(buf, &out, sizeof(out));
656 static inline unsigned long
657 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
661 if (copy_from_user(out, buf, sizeof(*out)))
666 struct shmid_ds tbuf_old;
668 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
671 out->shm_perm.uid = tbuf_old.shm_perm.uid;
672 out->shm_perm.gid = tbuf_old.shm_perm.gid;
673 out->shm_perm.mode = tbuf_old.shm_perm.mode;
682 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
686 return copy_to_user(buf, in, sizeof(*in));
691 if(in->shmmax > INT_MAX)
692 out.shmmax = INT_MAX;
694 out.shmmax = (int)in->shmmax;
696 out.shmmin = in->shmmin;
697 out.shmmni = in->shmmni;
698 out.shmseg = in->shmseg;
699 out.shmall = in->shmall;
701 return copy_to_user(buf, &out, sizeof(out));
709 * Calculate and add used RSS and swap pages of a shm.
710 * Called with shm_ids.rw_mutex held as a reader
712 static void shm_add_rss_swap(struct shmid_kernel *shp,
713 unsigned long *rss_add, unsigned long *swp_add)
717 inode = file_inode(shp->shm_file);
719 if (is_file_hugepages(shp->shm_file)) {
720 struct address_space *mapping = inode->i_mapping;
721 struct hstate *h = hstate_file(shp->shm_file);
722 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
725 struct shmem_inode_info *info = SHMEM_I(inode);
726 spin_lock(&info->lock);
727 *rss_add += inode->i_mapping->nrpages;
728 *swp_add += info->swapped;
729 spin_unlock(&info->lock);
731 *rss_add += inode->i_mapping->nrpages;
737 * Called with shm_ids.rw_mutex held as a reader
739 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
748 in_use = shm_ids(ns).in_use;
750 for (total = 0, next_id = 0; total < in_use; next_id++) {
751 struct kern_ipc_perm *ipc;
752 struct shmid_kernel *shp;
754 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
757 shp = container_of(ipc, struct shmid_kernel, shm_perm);
759 shm_add_rss_swap(shp, rss, swp);
766 * This function handles some shmctl commands which require the rw_mutex
767 * to be held in write mode.
768 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
770 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
771 struct shmid_ds __user *buf, int version)
773 struct kern_ipc_perm *ipcp;
774 struct shmid64_ds shmid64;
775 struct shmid_kernel *shp;
778 if (cmd == IPC_SET) {
779 if (copy_shmid_from_user(&shmid64, buf, version))
783 down_write(&shm_ids(ns).rw_mutex);
786 ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
787 &shmid64.shm_perm, 0);
793 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
795 err = security_shm_shmctl(shp, cmd);
801 ipc_lock_object(&shp->shm_perm);
802 /* do_shm_rmid unlocks the ipc object and rcu */
803 do_shm_rmid(ns, ipcp);
806 ipc_lock_object(&shp->shm_perm);
807 err = ipc_update_perm(&shmid64.shm_perm, ipcp);
810 shp->shm_ctim = get_seconds();
818 ipc_unlock_object(&shp->shm_perm);
822 up_write(&shm_ids(ns).rw_mutex);
826 static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
827 int cmd, int version, void __user *buf)
830 struct shmid_kernel *shp;
832 /* preliminary security checks for *_INFO */
833 if (cmd == IPC_INFO || cmd == SHM_INFO) {
834 err = security_shm_shmctl(NULL, cmd);
842 struct shminfo64 shminfo;
844 memset(&shminfo, 0, sizeof(shminfo));
845 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
846 shminfo.shmmax = ns->shm_ctlmax;
847 shminfo.shmall = ns->shm_ctlall;
849 shminfo.shmmin = SHMMIN;
850 if(copy_shminfo_to_user (buf, &shminfo, version))
853 down_read(&shm_ids(ns).rw_mutex);
854 err = ipc_get_maxid(&shm_ids(ns));
855 up_read(&shm_ids(ns).rw_mutex);
863 struct shm_info shm_info;
865 memset(&shm_info, 0, sizeof(shm_info));
866 down_read(&shm_ids(ns).rw_mutex);
867 shm_info.used_ids = shm_ids(ns).in_use;
868 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
869 shm_info.shm_tot = ns->shm_tot;
870 shm_info.swap_attempts = 0;
871 shm_info.swap_successes = 0;
872 err = ipc_get_maxid(&shm_ids(ns));
873 up_read(&shm_ids(ns).rw_mutex);
874 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
879 err = err < 0 ? 0 : err;
885 struct shmid64_ds tbuf;
889 if (cmd == SHM_STAT) {
890 shp = shm_obtain_object(ns, shmid);
895 result = shp->shm_perm.id;
897 shp = shm_obtain_object_check(ns, shmid);
906 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
909 err = security_shm_shmctl(shp, cmd);
913 memset(&tbuf, 0, sizeof(tbuf));
914 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
915 tbuf.shm_segsz = shp->shm_segsz;
916 tbuf.shm_atime = shp->shm_atim;
917 tbuf.shm_dtime = shp->shm_dtim;
918 tbuf.shm_ctime = shp->shm_ctim;
919 tbuf.shm_cpid = shp->shm_cprid;
920 tbuf.shm_lpid = shp->shm_lprid;
921 tbuf.shm_nattch = shp->shm_nattch;
924 if (copy_shmid_to_user(buf, &tbuf, version))
940 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
942 struct shmid_kernel *shp;
944 struct ipc_namespace *ns;
946 if (cmd < 0 || shmid < 0)
949 version = ipc_parse_version(&cmd);
950 ns = current->nsproxy->ipc_ns;
957 return shmctl_nolock(ns, shmid, cmd, version, buf);
960 return shmctl_down(ns, shmid, cmd, buf, version);
964 struct file *shm_file;
967 shp = shm_obtain_object_check(ns, shmid);
973 audit_ipc_obj(&(shp->shm_perm));
974 err = security_shm_shmctl(shp, cmd);
978 ipc_lock_object(&shp->shm_perm);
979 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
980 kuid_t euid = current_euid();
982 if (!uid_eq(euid, shp->shm_perm.uid) &&
983 !uid_eq(euid, shp->shm_perm.cuid))
985 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
989 shm_file = shp->shm_file;
990 if (is_file_hugepages(shm_file))
993 if (cmd == SHM_LOCK) {
994 struct user_struct *user = current_user();
995 err = shmem_lock(shm_file, 1, user);
996 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
997 shp->shm_perm.mode |= SHM_LOCKED;
998 shp->mlock_user = user;
1004 if (!(shp->shm_perm.mode & SHM_LOCKED))
1006 shmem_lock(shm_file, 0, shp->mlock_user);
1007 shp->shm_perm.mode &= ~SHM_LOCKED;
1008 shp->mlock_user = NULL;
1010 ipc_unlock_object(&shp->shm_perm);
1012 shmem_unlock_mapping(shm_file->f_mapping);
1022 ipc_unlock_object(&shp->shm_perm);
1029 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1031 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1032 * "raddr" thing points to kernel space, and there has to be a wrapper around
1035 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
1036 unsigned long shmlba)
1038 struct shmid_kernel *shp;
1043 unsigned long flags;
1046 struct ipc_namespace *ns;
1047 struct shm_file_data *sfd;
1050 unsigned long populate = 0;
1055 else if ((addr = (ulong)shmaddr)) {
1056 if (addr & (shmlba - 1)) {
1057 if (shmflg & SHM_RND)
1058 addr &= ~(shmlba - 1); /* round down */
1060 #ifndef __ARCH_FORCE_SHMLBA
1061 if (addr & ~PAGE_MASK)
1065 flags = MAP_SHARED | MAP_FIXED;
1067 if ((shmflg & SHM_REMAP))
1073 if (shmflg & SHM_RDONLY) {
1076 f_mode = FMODE_READ;
1078 prot = PROT_READ | PROT_WRITE;
1079 acc_mode = S_IRUGO | S_IWUGO;
1080 f_mode = FMODE_READ | FMODE_WRITE;
1082 if (shmflg & SHM_EXEC) {
1084 acc_mode |= S_IXUGO;
1088 * We cannot rely on the fs check since SYSV IPC does have an
1089 * additional creator id...
1091 ns = current->nsproxy->ipc_ns;
1093 shp = shm_obtain_object_check(ns, shmid);
1100 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1103 err = security_shm_shmat(shp, shmaddr, shmflg);
1107 ipc_lock_object(&shp->shm_perm);
1108 path = shp->shm_file->f_path;
1111 size = i_size_read(path.dentry->d_inode);
1112 ipc_unlock_object(&shp->shm_perm);
1116 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1122 file = alloc_file(&path, f_mode,
1123 is_file_hugepages(shp->shm_file) ?
1124 &shm_file_operations_huge :
1125 &shm_file_operations);
1126 err = PTR_ERR(file);
1133 file->private_data = sfd;
1134 file->f_mapping = shp->shm_file->f_mapping;
1135 sfd->id = shp->shm_perm.id;
1136 sfd->ns = get_ipc_ns(ns);
1137 sfd->file = shp->shm_file;
1140 err = security_mmap_file(file, prot, flags);
1144 down_write(¤t->mm->mmap_sem);
1145 if (addr && !(shmflg & SHM_REMAP)) {
1147 if (find_vma_intersection(current->mm, addr, addr + size))
1150 * If shm segment goes below stack, make sure there is some
1151 * space left for the stack to grow (at least 4 pages).
1153 if (addr < current->mm->start_stack &&
1154 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1158 addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate);
1161 if (IS_ERR_VALUE(addr))
1164 up_write(¤t->mm->mmap_sem);
1166 mm_populate(addr, populate);
1172 down_write(&shm_ids(ns).rw_mutex);
1173 shp = shm_lock(ns, shmid);
1174 BUG_ON(IS_ERR(shp));
1176 if (shm_may_destroy(ns, shp))
1177 shm_destroy(ns, shp);
1180 up_write(&shm_ids(ns).rw_mutex);
1189 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1194 err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1197 force_successful_syscall_return();
1202 * detach and kill segment if marked destroyed.
1203 * The work is done in shm_close.
1205 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1207 struct mm_struct *mm = current->mm;
1208 struct vm_area_struct *vma;
1209 unsigned long addr = (unsigned long)shmaddr;
1210 int retval = -EINVAL;
1213 struct vm_area_struct *next;
1216 if (addr & ~PAGE_MASK)
1219 down_write(&mm->mmap_sem);
1222 * This function tries to be smart and unmap shm segments that
1223 * were modified by partial mlock or munmap calls:
1224 * - It first determines the size of the shm segment that should be
1225 * unmapped: It searches for a vma that is backed by shm and that
1226 * started at address shmaddr. It records it's size and then unmaps
1228 * - Then it unmaps all shm vmas that started at shmaddr and that
1229 * are within the initially determined size.
1230 * Errors from do_munmap are ignored: the function only fails if
1231 * it's called with invalid parameters or if it's called to unmap
1232 * a part of a vma. Both calls in this function are for full vmas,
1233 * the parameters are directly copied from the vma itself and always
1234 * valid - therefore do_munmap cannot fail. (famous last words?)
1237 * If it had been mremap()'d, the starting address would not
1238 * match the usual checks anyway. So assume all vma's are
1239 * above the starting address given.
1241 vma = find_vma(mm, addr);
1245 next = vma->vm_next;
1248 * Check if the starting address would match, i.e. it's
1249 * a fragment created by mprotect() and/or munmap(), or it
1250 * otherwise it starts at this address with no hassles.
1252 if ((vma->vm_ops == &shm_vm_ops) &&
1253 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1256 size = file_inode(vma->vm_file)->i_size;
1257 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1259 * We discovered the size of the shm segment, so
1260 * break out of here and fall through to the next
1261 * loop that uses the size information to stop
1262 * searching for matching vma's.
1272 * We need look no further than the maximum address a fragment
1273 * could possibly have landed at. Also cast things to loff_t to
1274 * prevent overflows and make comparisons vs. equal-width types.
1276 size = PAGE_ALIGN(size);
1277 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1278 next = vma->vm_next;
1280 /* finding a matching vma now does not alter retval */
1281 if ((vma->vm_ops == &shm_vm_ops) &&
1282 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1284 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1288 #else /* CONFIG_MMU */
1289 /* under NOMMU conditions, the exact address to be destroyed must be
1292 if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1293 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1299 up_write(&mm->mmap_sem);
1303 #ifdef CONFIG_PROC_FS
1304 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1306 struct user_namespace *user_ns = seq_user_ns(s);
1307 struct shmid_kernel *shp = it;
1308 unsigned long rss = 0, swp = 0;
1310 shm_add_rss_swap(shp, &rss, &swp);
1312 #if BITS_PER_LONG <= 32
1313 #define SIZE_SPEC "%10lu"
1315 #define SIZE_SPEC "%21lu"
1318 return seq_printf(s,
1319 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1320 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1321 SIZE_SPEC " " SIZE_SPEC "\n",
1329 from_kuid_munged(user_ns, shp->shm_perm.uid),
1330 from_kgid_munged(user_ns, shp->shm_perm.gid),
1331 from_kuid_munged(user_ns, shp->shm_perm.cuid),
1332 from_kgid_munged(user_ns, shp->shm_perm.cgid),