blob: 92fe9236258b15192fe78ae615891c624b91c036 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/ipc/shm.c
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.
7 *
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>
15 *
Steve Grubb073115d2006-04-02 17:07:33 -040016 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
Kirill Korotaev4e982312006-10-02 02:18:22 -070018 *
19 * namespaces support
20 * OpenVZ, SWsoft Inc.
21 * Pavel Emelianov <xemul@openvz.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022 */
23
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <linux/slab.h>
25#include <linux/mm.h>
26#include <linux/hugetlb.h>
27#include <linux/shm.h>
28#include <linux/init.h>
29#include <linux/file.h>
30#include <linux/mman.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#include <linux/shmem_fs.h>
32#include <linux/security.h>
33#include <linux/syscalls.h>
34#include <linux/audit.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080035#include <linux/capability.h>
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -070036#include <linux/ptrace.h>
Mike Waychison19b49462005-09-06 15:17:10 -070037#include <linux/seq_file.h>
Nadia Derbey3e148c72007-10-18 23:40:54 -070038#include <linux/rwsem.h>
Kirill Korotaev4e982312006-10-02 02:18:22 -070039#include <linux/nsproxy.h>
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080040#include <linux/mount.h>
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080041#include <linux/ipc_namespace.h>
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -070042
Linus Torvalds1da177e2005-04-16 15:20:36 -070043#include <asm/uaccess.h>
44
45#include "util.h"
46
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080047struct shm_file_data {
48 int id;
49 struct ipc_namespace *ns;
50 struct file *file;
51 const struct vm_operations_struct *vm_ops;
52};
53
54#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
55
Arjan van de Ven9a321442007-02-12 00:55:35 -080056static const struct file_operations shm_file_operations;
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +040057static const struct vm_operations_struct shm_vm_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080059#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
Kirill Korotaev4e982312006-10-02 02:18:22 -070061#define shm_unlock(shp) \
62 ipc_unlock(&(shp)->shm_perm)
Kirill Korotaev4e982312006-10-02 02:18:22 -070063
Nadia Derbey7748dbf2007-10-18 23:40:49 -070064static int newseg(struct ipc_namespace *, struct ipc_params *);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080065static void shm_open(struct vm_area_struct *vma);
66static void shm_close(struct vm_area_struct *vma);
Kirill Korotaev4e982312006-10-02 02:18:22 -070067static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -070068#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -070069static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
Linus Torvalds1da177e2005-04-16 15:20:36 -070070#endif
71
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080072void shm_init_ns(struct ipc_namespace *ns)
Kirill Korotaev4e982312006-10-02 02:18:22 -070073{
Kirill Korotaev4e982312006-10-02 02:18:22 -070074 ns->shm_ctlmax = SHMMAX;
75 ns->shm_ctlall = SHMALL;
76 ns->shm_ctlmni = SHMMNI;
77 ns->shm_tot = 0;
WANG Conge8148f72009-01-06 14:42:49 -080078 ipc_init_ids(&shm_ids(ns));
Kirill Korotaev4e982312006-10-02 02:18:22 -070079}
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
Nadia Derbeyf4566f02007-10-18 23:40:53 -070081/*
Nadia Derbey3e148c72007-10-18 23:40:54 -070082 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
83 * Only shm_ids.rw_mutex remains locked on exit.
Nadia Derbeyf4566f02007-10-18 23:40:53 -070084 */
Pierre Peiffer01b8b072008-02-08 04:18:57 -080085static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
Kirill Korotaev4e982312006-10-02 02:18:22 -070086{
Pierre Peiffer01b8b072008-02-08 04:18:57 -080087 struct shmid_kernel *shp;
88 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
89
Kirill Korotaev4e982312006-10-02 02:18:22 -070090 if (shp->shm_nattch){
91 shp->shm_perm.mode |= SHM_DEST;
92 /* Do not find it any more */
93 shp->shm_perm.key = IPC_PRIVATE;
94 shm_unlock(shp);
95 } else
96 shm_destroy(ns, shp);
97}
98
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080099#ifdef CONFIG_IPC_NS
Kirill Korotaev4e982312006-10-02 02:18:22 -0700100void shm_exit_ns(struct ipc_namespace *ns)
101{
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800102 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
Serge E. Hallyn7d6feeb2009-12-15 16:47:27 -0800103 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700104}
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800105#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106
107void __init shm_init (void)
108{
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800109 shm_init_ns(&init_ipc_ns);
Mike Waychison19b49462005-09-06 15:17:10 -0700110 ipc_init_proc_interface("sysvipc/shm",
111 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
Kirill Korotaev4e982312006-10-02 02:18:22 -0700112 IPC_SHM_IDS, sysvipc_shm_proc_show);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113}
114
Nadia Derbey3e148c72007-10-18 23:40:54 -0700115/*
Nadia Derbey3e148c72007-10-18 23:40:54 -0700116 * shm_lock_(check_) routines are called in the paths where the rw_mutex
Nadia Derbey00c2bf82008-07-25 01:48:03 -0700117 * is not necessarily held.
Nadia Derbey3e148c72007-10-18 23:40:54 -0700118 */
Nadia Derbey023a5352007-10-18 23:40:51 -0700119static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700121 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
122
Pierre Peifferb1ed88b2008-02-06 01:36:23 -0800123 if (IS_ERR(ipcp))
124 return (struct shmid_kernel *)ipcp;
125
Nadia Derbey03f02c72007-10-18 23:40:51 -0700126 return container_of(ipcp, struct shmid_kernel, shm_perm);
Nadia Derbey023a5352007-10-18 23:40:51 -0700127}
128
129static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
130 int id)
131{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700132 struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
133
Pierre Peifferb1ed88b2008-02-06 01:36:23 -0800134 if (IS_ERR(ipcp))
135 return (struct shmid_kernel *)ipcp;
136
Nadia Derbey03f02c72007-10-18 23:40:51 -0700137 return container_of(ipcp, struct shmid_kernel, shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138}
139
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700140static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700142 ipc_rmid(&shm_ids(ns), &s->shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143}
144
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800146/* This is called by fork, once for every shm attach. */
147static void shm_open(struct vm_area_struct *vma)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700148{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800149 struct file *file = vma->vm_file;
150 struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 struct shmid_kernel *shp;
152
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800153 shp = shm_lock(sfd->ns, sfd->id);
Nadia Derbey023a5352007-10-18 23:40:51 -0700154 BUG_ON(IS_ERR(shp));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 shp->shm_atim = get_seconds();
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700156 shp->shm_lprid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 shp->shm_nattch++;
158 shm_unlock(shp);
159}
160
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161/*
162 * shm_destroy - free the struct shmid_kernel
163 *
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700164 * @ns: namespace
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 * @shp: struct to free
166 *
Nadia Derbey3e148c72007-10-18 23:40:54 -0700167 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 * but returns with shp unlocked and freed.
169 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700170static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700172 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700173 shm_rmid(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 shm_unlock(shp);
175 if (!is_file_hugepages(shp->shm_file))
176 shmem_lock(shp->shm_file, 0, shp->mlock_user);
Hugh Dickins353d5c32009-08-24 16:30:28 +0100177 else if (shp->mlock_user)
Josef Sipek6d630792006-12-08 02:37:11 -0800178 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 shp->mlock_user);
180 fput (shp->shm_file);
181 security_shm_free(shp);
182 ipc_rcu_putref(shp);
183}
184
185/*
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800186 * remove the attach descriptor vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 * free memory for segment if it is marked destroyed.
188 * The descriptor has already been removed from the current->mm->mmap list
189 * and will later be kfree()d.
190 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800191static void shm_close(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800193 struct file * file = vma->vm_file;
194 struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 struct shmid_kernel *shp;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800196 struct ipc_namespace *ns = sfd->ns;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700197
Nadia Derbey3e148c72007-10-18 23:40:54 -0700198 down_write(&shm_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 /* remove from the list of attaches of the shm segment */
Nadia Derbey00c2bf82008-07-25 01:48:03 -0700200 shp = shm_lock(ns, sfd->id);
Nadia Derbey023a5352007-10-18 23:40:51 -0700201 BUG_ON(IS_ERR(shp));
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700202 shp->shm_lprid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 shp->shm_dtim = get_seconds();
204 shp->shm_nattch--;
205 if(shp->shm_nattch == 0 &&
Andrew Mortonb33291c2006-01-08 01:02:21 -0800206 shp->shm_perm.mode & SHM_DEST)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700207 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 else
209 shm_unlock(shp);
Nadia Derbey3e148c72007-10-18 23:40:54 -0700210 up_write(&shm_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211}
212
Nick Piggind0217ac2007-07-19 01:47:03 -0700213static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800214{
215 struct file *file = vma->vm_file;
216 struct shm_file_data *sfd = shm_file_data(file);
217
Nick Piggind0217ac2007-07-19 01:47:03 -0700218 return sfd->vm_ops->fault(vma, vmf);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800219}
220
221#ifdef CONFIG_NUMA
Adrian Bunkd823e3e2007-10-16 23:26:42 -0700222static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800223{
224 struct file *file = vma->vm_file;
225 struct shm_file_data *sfd = shm_file_data(file);
226 int err = 0;
227 if (sfd->vm_ops->set_policy)
228 err = sfd->vm_ops->set_policy(vma, new);
229 return err;
230}
231
Adrian Bunkd823e3e2007-10-16 23:26:42 -0700232static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
233 unsigned long addr)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800234{
235 struct file *file = vma->vm_file;
236 struct shm_file_data *sfd = shm_file_data(file);
237 struct mempolicy *pol = NULL;
238
239 if (sfd->vm_ops->get_policy)
240 pol = sfd->vm_ops->get_policy(vma, addr);
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -0700241 else if (vma->vm_policy)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800242 pol = vma->vm_policy;
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -0700243
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800244 return pol;
245}
246#endif
247
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248static int shm_mmap(struct file * file, struct vm_area_struct * vma)
249{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800250 struct shm_file_data *sfd = shm_file_data(file);
David Howellsb0e15192006-01-06 00:11:42 -0800251 int ret;
252
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800253 ret = sfd->file->f_op->mmap(sfd->file, vma);
254 if (ret != 0)
255 return ret;
256 sfd->vm_ops = vma->vm_ops;
David Howells2e92a3b2007-07-31 00:37:24 -0700257#ifdef CONFIG_MMU
Nick Piggin54cb8822007-07-19 01:46:59 -0700258 BUG_ON(!sfd->vm_ops->fault);
David Howells2e92a3b2007-07-31 00:37:24 -0700259#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800260 vma->vm_ops = &shm_vm_ops;
261 shm_open(vma);
David Howellsb0e15192006-01-06 00:11:42 -0800262
263 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264}
265
Kirill Korotaev4e982312006-10-02 02:18:22 -0700266static int shm_release(struct inode *ino, struct file *file)
267{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800268 struct shm_file_data *sfd = shm_file_data(file);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700269
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800270 put_ipc_ns(sfd->ns);
271 shm_file_data(file) = NULL;
272 kfree(sfd);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700273 return 0;
274}
275
Adam Litke516dffd2007-03-01 15:46:08 -0800276static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
277{
278 int (*fsync) (struct file *, struct dentry *, int datasync);
279 struct shm_file_data *sfd = shm_file_data(file);
280 int ret = -EINVAL;
281
282 fsync = sfd->file->f_op->fsync;
283 if (fsync)
284 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
285 return ret;
286}
287
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800288static unsigned long shm_get_unmapped_area(struct file *file,
289 unsigned long addr, unsigned long len, unsigned long pgoff,
290 unsigned long flags)
291{
292 struct shm_file_data *sfd = shm_file_data(file);
Al Viroc4caa772009-11-30 08:38:43 -0500293 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
294 pgoff, flags);
Adam Litke516dffd2007-03-01 15:46:08 -0800295}
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800296
Arjan van de Ven9a321442007-02-12 00:55:35 -0800297static const struct file_operations shm_file_operations = {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700298 .mmap = shm_mmap,
Adam Litke516dffd2007-03-01 15:46:08 -0800299 .fsync = shm_fsync,
Kirill Korotaev4e982312006-10-02 02:18:22 -0700300 .release = shm_release,
Al Viroc4caa772009-11-30 08:38:43 -0500301};
302
303static const struct file_operations shm_file_operations_huge = {
304 .mmap = shm_mmap,
305 .fsync = shm_fsync,
306 .release = shm_release,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800307 .get_unmapped_area = shm_get_unmapped_area,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308};
309
Al Viroc4caa772009-11-30 08:38:43 -0500310int is_file_shm_hugepages(struct file *file)
311{
312 return file->f_op == &shm_file_operations_huge;
313}
314
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +0400315static const struct vm_operations_struct shm_vm_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 .open = shm_open, /* callback for a new vm-area open */
317 .close = shm_close, /* callback for when the vm-area is released */
Nick Piggin54cb8822007-07-19 01:46:59 -0700318 .fault = shm_fault,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800319#if defined(CONFIG_NUMA)
320 .set_policy = shm_set_policy,
321 .get_policy = shm_get_policy,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322#endif
323};
324
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700325/**
326 * newseg - Create a new shared memory segment
327 * @ns: namespace
328 * @params: ptr to the structure that contains key, size and shmflg
329 *
Nadia Derbey3e148c72007-10-18 23:40:54 -0700330 * Called with shm_ids.rw_mutex held as a writer.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700331 */
332
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700333static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334{
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700335 key_t key = params->key;
336 int shmflg = params->flg;
337 size_t size = params->u.size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 int error;
339 struct shmid_kernel *shp;
340 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
341 struct file * file;
342 char name[13];
343 int id;
Mel Gorman5a6fe122009-02-10 14:02:27 +0000344 int acctflag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345
Kirill Korotaev4e982312006-10-02 02:18:22 -0700346 if (size < SHMMIN || size > ns->shm_ctlmax)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 return -EINVAL;
348
Guy Streeterf66d45e2007-01-23 12:20:04 -0600349 if (ns->shm_tot + numpages > ns->shm_ctlall)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 return -ENOSPC;
351
352 shp = ipc_rcu_alloc(sizeof(*shp));
353 if (!shp)
354 return -ENOMEM;
355
356 shp->shm_perm.key = key;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800357 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 shp->mlock_user = NULL;
359
360 shp->shm_perm.security = NULL;
361 error = security_shm_alloc(shp);
362 if (error) {
363 ipc_rcu_putref(shp);
364 return error;
365 }
366
Eric W. Biederman9d665862007-06-16 10:16:16 -0700367 sprintf (name, "SYSV%08x", key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 if (shmflg & SHM_HUGETLB) {
Mel Gorman5a6fe122009-02-10 14:02:27 +0000369 /* hugetlb_file_setup applies strict accounting */
370 if (shmflg & SHM_NORESERVE)
371 acctflag = VM_NORESERVE;
Hugh Dickins353d5c32009-08-24 16:30:28 +0100372 file = hugetlb_file_setup(name, size, acctflag,
Eric B Munson6bfde052009-09-21 17:03:43 -0700373 &shp->mlock_user, HUGETLB_SHMFS_INODE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 } else {
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800375 /*
376 * Do not allow no accounting for OVERCOMMIT_NEVER, even
377 * if it's asked for.
378 */
379 if ((shmflg & SHM_NORESERVE) &&
380 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
Linus Torvaldsfc8744a2009-01-31 15:08:56 -0800381 acctflag = VM_NORESERVE;
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800382 file = shmem_file_setup(name, size, acctflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 }
384 error = PTR_ERR(file);
385 if (IS_ERR(file))
386 goto no_file;
387
Pierre Peiffer48dea402008-04-29 01:00:35 -0700388 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
Pierre Peiffer283bb7f2007-10-18 23:40:57 -0700389 if (id < 0) {
390 error = id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391 goto no_id;
Pierre Peiffer283bb7f2007-10-18 23:40:57 -0700392 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700394 shp->shm_cprid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 shp->shm_lprid = 0;
396 shp->shm_atim = shp->shm_dtim = 0;
397 shp->shm_ctim = get_seconds();
398 shp->shm_segsz = size;
399 shp->shm_nattch = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 shp->shm_file = file;
Badari Pulavarty30475cc2007-06-16 10:15:59 -0700401 /*
402 * shmid gets reported as "inode#" in /proc/pid/maps.
403 * proc-ps tools use this. Changing this will break them.
404 */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700405 file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
Krishnakumar R551110a2005-10-29 18:16:45 -0700406
Kirill Korotaev4e982312006-10-02 02:18:22 -0700407 ns->shm_tot += numpages;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700408 error = shp->shm_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 shm_unlock(shp);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700410 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411
412no_id:
Hugh Dickins2195d282009-09-12 12:21:27 +0100413 if (is_file_hugepages(file) && shp->mlock_user)
Hugh Dickins353d5c32009-08-24 16:30:28 +0100414 user_shm_unlock(size, shp->mlock_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 fput(file);
416no_file:
417 security_shm_free(shp);
418 ipc_rcu_putref(shp);
419 return error;
420}
421
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700422/*
Nadia Derbey3e148c72007-10-18 23:40:54 -0700423 * Called with shm_ids.rw_mutex and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700424 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700425static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700426{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700427 struct shmid_kernel *shp;
428
429 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
430 return security_shm_associate(shp, shmflg);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700431}
432
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700433/*
Nadia Derbey3e148c72007-10-18 23:40:54 -0700434 * Called with shm_ids.rw_mutex and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700435 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700436static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
437 struct ipc_params *params)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700438{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700439 struct shmid_kernel *shp;
440
441 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
442 if (shp->shm_segsz < params->u.size)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700443 return -EINVAL;
444
445 return 0;
446}
447
Heiko Carstensd5460c92009-01-14 14:14:27 +0100448SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700450 struct ipc_namespace *ns;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700451 struct ipc_ops shm_ops;
452 struct ipc_params shm_params;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453
Kirill Korotaev4e982312006-10-02 02:18:22 -0700454 ns = current->nsproxy->ipc_ns;
455
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700456 shm_ops.getnew = newseg;
457 shm_ops.associate = shm_security;
458 shm_ops.more_checks = shm_more_checks;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700459
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700460 shm_params.key = key;
461 shm_params.flg = shmflg;
462 shm_params.u.size = size;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700463
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700464 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465}
466
467static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
468{
469 switch(version) {
470 case IPC_64:
471 return copy_to_user(buf, in, sizeof(*in));
472 case IPC_OLD:
473 {
474 struct shmid_ds out;
475
476 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
477 out.shm_segsz = in->shm_segsz;
478 out.shm_atime = in->shm_atime;
479 out.shm_dtime = in->shm_dtime;
480 out.shm_ctime = in->shm_ctime;
481 out.shm_cpid = in->shm_cpid;
482 out.shm_lpid = in->shm_lpid;
483 out.shm_nattch = in->shm_nattch;
484
485 return copy_to_user(buf, &out, sizeof(out));
486 }
487 default:
488 return -EINVAL;
489 }
490}
491
Pierre Peiffer016d7132008-04-29 01:00:50 -0700492static inline unsigned long
493copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494{
495 switch(version) {
496 case IPC_64:
Pierre Peiffer016d7132008-04-29 01:00:50 -0700497 if (copy_from_user(out, buf, sizeof(*out)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 case IPC_OLD:
501 {
502 struct shmid_ds tbuf_old;
503
504 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
505 return -EFAULT;
506
Pierre Peiffer016d7132008-04-29 01:00:50 -0700507 out->shm_perm.uid = tbuf_old.shm_perm.uid;
508 out->shm_perm.gid = tbuf_old.shm_perm.gid;
509 out->shm_perm.mode = tbuf_old.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510
511 return 0;
512 }
513 default:
514 return -EINVAL;
515 }
516}
517
518static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
519{
520 switch(version) {
521 case IPC_64:
522 return copy_to_user(buf, in, sizeof(*in));
523 case IPC_OLD:
524 {
525 struct shminfo out;
526
527 if(in->shmmax > INT_MAX)
528 out.shmmax = INT_MAX;
529 else
530 out.shmmax = (int)in->shmmax;
531
532 out.shmmin = in->shmmin;
533 out.shmmni = in->shmmni;
534 out.shmseg = in->shmseg;
535 out.shmall = in->shmall;
536
537 return copy_to_user(buf, &out, sizeof(out));
538 }
539 default:
540 return -EINVAL;
541 }
542}
543
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700544/*
Nadia Derbey3e148c72007-10-18 23:40:54 -0700545 * Called with shm_ids.rw_mutex held as a reader
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700546 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700547static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
548 unsigned long *swp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700550 int next_id;
551 int total, in_use;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552
553 *rss = 0;
554 *swp = 0;
555
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700556 in_use = shm_ids(ns).in_use;
557
558 for (total = 0, next_id = 0; total < in_use; next_id++) {
Tony Battersbye562aeb2009-04-02 16:58:26 -0700559 struct kern_ipc_perm *ipc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 struct shmid_kernel *shp;
561 struct inode *inode;
562
Tony Battersbye562aeb2009-04-02 16:58:26 -0700563 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
564 if (ipc == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 continue;
Tony Battersbye562aeb2009-04-02 16:58:26 -0700566 shp = container_of(ipc, struct shmid_kernel, shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567
Josef Sipek6d630792006-12-08 02:37:11 -0800568 inode = shp->shm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569
570 if (is_file_hugepages(shp->shm_file)) {
571 struct address_space *mapping = inode->i_mapping;
Andi Kleena5516432008-07-23 21:27:41 -0700572 struct hstate *h = hstate_file(shp->shm_file);
573 *rss += pages_per_huge_page(h) * mapping->nrpages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 } else {
Tony Battersbya68e61e2009-02-04 15:12:04 -0800575#ifdef CONFIG_SHMEM
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576 struct shmem_inode_info *info = SHMEM_I(inode);
577 spin_lock(&info->lock);
578 *rss += inode->i_mapping->nrpages;
579 *swp += info->swapped;
580 spin_unlock(&info->lock);
Tony Battersbya68e61e2009-02-04 15:12:04 -0800581#else
582 *rss += inode->i_mapping->nrpages;
583#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700585
586 total++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 }
588}
589
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700590/*
591 * This function handles some shmctl commands which require the rw_mutex
592 * to be held in write mode.
593 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
594 */
595static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
596 struct shmid_ds __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597{
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700598 struct kern_ipc_perm *ipcp;
Pierre Peiffer016d7132008-04-29 01:00:50 -0700599 struct shmid64_ds shmid64;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 struct shmid_kernel *shp;
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700601 int err;
602
603 if (cmd == IPC_SET) {
Pierre Peiffer016d7132008-04-29 01:00:50 -0700604 if (copy_shmid_from_user(&shmid64, buf, version))
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700605 return -EFAULT;
606 }
607
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700608 ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
609 if (IS_ERR(ipcp))
610 return PTR_ERR(ipcp);
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700611
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700612 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700613
614 err = security_shm_shmctl(shp, cmd);
615 if (err)
616 goto out_unlock;
617 switch (cmd) {
618 case IPC_RMID:
619 do_shm_rmid(ns, ipcp);
620 goto out_up;
621 case IPC_SET:
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700622 ipc_update_perm(&shmid64.shm_perm, ipcp);
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700623 shp->shm_ctim = get_seconds();
624 break;
625 default:
626 err = -EINVAL;
627 }
628out_unlock:
629 shm_unlock(shp);
630out_up:
631 up_write(&shm_ids(ns).rw_mutex);
632 return err;
633}
634
Heiko Carstensd5460c92009-01-14 14:14:27 +0100635SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700636{
637 struct shmid_kernel *shp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 int err, version;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700639 struct ipc_namespace *ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640
641 if (cmd < 0 || shmid < 0) {
642 err = -EINVAL;
643 goto out;
644 }
645
646 version = ipc_parse_version(&cmd);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700647 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648
649 switch (cmd) { /* replace with proc interface ? */
650 case IPC_INFO:
651 {
652 struct shminfo64 shminfo;
653
654 err = security_shm_shmctl(NULL, cmd);
655 if (err)
656 return err;
657
WANG Conge8148f72009-01-06 14:42:49 -0800658 memset(&shminfo, 0, sizeof(shminfo));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700659 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
660 shminfo.shmmax = ns->shm_ctlmax;
661 shminfo.shmall = ns->shm_ctlall;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662
663 shminfo.shmmin = SHMMIN;
664 if(copy_shminfo_to_user (buf, &shminfo, version))
665 return -EFAULT;
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700666
Nadia Derbey3e148c72007-10-18 23:40:54 -0700667 down_read(&shm_ids(ns).rw_mutex);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700668 err = ipc_get_maxid(&shm_ids(ns));
Nadia Derbey3e148c72007-10-18 23:40:54 -0700669 up_read(&shm_ids(ns).rw_mutex);
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700670
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 if(err<0)
672 err = 0;
673 goto out;
674 }
675 case SHM_INFO:
676 {
677 struct shm_info shm_info;
678
679 err = security_shm_shmctl(NULL, cmd);
680 if (err)
681 return err;
682
WANG Conge8148f72009-01-06 14:42:49 -0800683 memset(&shm_info, 0, sizeof(shm_info));
Nadia Derbey3e148c72007-10-18 23:40:54 -0700684 down_read(&shm_ids(ns).rw_mutex);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700685 shm_info.used_ids = shm_ids(ns).in_use;
686 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
687 shm_info.shm_tot = ns->shm_tot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 shm_info.swap_attempts = 0;
689 shm_info.swap_successes = 0;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700690 err = ipc_get_maxid(&shm_ids(ns));
Nadia Derbey3e148c72007-10-18 23:40:54 -0700691 up_read(&shm_ids(ns).rw_mutex);
WANG Conge8148f72009-01-06 14:42:49 -0800692 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 err = -EFAULT;
694 goto out;
695 }
696
697 err = err < 0 ? 0 : err;
698 goto out;
699 }
700 case SHM_STAT:
701 case IPC_STAT:
702 {
703 struct shmid64_ds tbuf;
704 int result;
Nadia Derbey023a5352007-10-18 23:40:51 -0700705
Nadia Derbey023a5352007-10-18 23:40:51 -0700706 if (cmd == SHM_STAT) {
707 shp = shm_lock(ns, shmid);
708 if (IS_ERR(shp)) {
709 err = PTR_ERR(shp);
710 goto out;
711 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700712 result = shp->shm_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 } else {
Nadia Derbey023a5352007-10-18 23:40:51 -0700714 shp = shm_lock_check(ns, shmid);
715 if (IS_ERR(shp)) {
716 err = PTR_ERR(shp);
717 goto out;
718 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 result = 0;
720 }
WANG Conge8148f72009-01-06 14:42:49 -0800721 err = -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 if (ipcperms (&shp->shm_perm, S_IRUGO))
723 goto out_unlock;
724 err = security_shm_shmctl(shp, cmd);
725 if (err)
726 goto out_unlock;
Nadia Derbey023a5352007-10-18 23:40:51 -0700727 memset(&tbuf, 0, sizeof(tbuf));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
729 tbuf.shm_segsz = shp->shm_segsz;
730 tbuf.shm_atime = shp->shm_atim;
731 tbuf.shm_dtime = shp->shm_dtim;
732 tbuf.shm_ctime = shp->shm_ctim;
733 tbuf.shm_cpid = shp->shm_cprid;
734 tbuf.shm_lpid = shp->shm_lprid;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800735 tbuf.shm_nattch = shp->shm_nattch;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 shm_unlock(shp);
737 if(copy_shmid_to_user (buf, &tbuf, version))
738 err = -EFAULT;
739 else
740 err = result;
741 goto out;
742 }
743 case SHM_LOCK:
744 case SHM_UNLOCK:
745 {
Lee Schermerhorn89e004ea2008-10-18 20:26:43 -0700746 struct file *uninitialized_var(shm_file);
747
748 lru_add_drain_all(); /* drain pagevecs to lru lists */
749
Nadia Derbey023a5352007-10-18 23:40:51 -0700750 shp = shm_lock_check(ns, shmid);
751 if (IS_ERR(shp)) {
752 err = PTR_ERR(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 goto out;
754 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755
Al Viroa33e6752008-12-10 03:40:06 -0500756 audit_ipc_obj(&(shp->shm_perm));
Steve Grubb073115d2006-04-02 17:07:33 -0400757
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 if (!capable(CAP_IPC_LOCK)) {
David Howells414c0702008-11-14 10:39:06 +1100759 uid_t euid = current_euid();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 err = -EPERM;
David Howells414c0702008-11-14 10:39:06 +1100761 if (euid != shp->shm_perm.uid &&
762 euid != shp->shm_perm.cuid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 goto out_unlock;
764 if (cmd == SHM_LOCK &&
765 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
766 goto out_unlock;
767 }
768
769 err = security_shm_shmctl(shp, cmd);
770 if (err)
771 goto out_unlock;
772
773 if(cmd==SHM_LOCK) {
David Howells86a264a2008-11-14 10:39:18 +1100774 struct user_struct *user = current_user();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 if (!is_file_hugepages(shp->shm_file)) {
776 err = shmem_lock(shp->shm_file, 1, user);
Pavel Emelianov7be77e22007-07-31 00:38:48 -0700777 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
Andrew Mortonb33291c2006-01-08 01:02:21 -0800778 shp->shm_perm.mode |= SHM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 shp->mlock_user = user;
780 }
781 }
782 } else if (!is_file_hugepages(shp->shm_file)) {
783 shmem_lock(shp->shm_file, 0, shp->mlock_user);
Andrew Mortonb33291c2006-01-08 01:02:21 -0800784 shp->shm_perm.mode &= ~SHM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785 shp->mlock_user = NULL;
786 }
787 shm_unlock(shp);
788 goto out;
789 }
790 case IPC_RMID:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791 case IPC_SET:
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700792 err = shmctl_down(ns, shmid, cmd, buf, version);
793 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 default:
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700795 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 }
797
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798out_unlock:
799 shm_unlock(shp);
800out:
801 return err;
802}
803
804/*
805 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
806 *
807 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
808 * "raddr" thing points to kernel space, and there has to be a wrapper around
809 * this.
810 */
811long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
812{
813 struct shmid_kernel *shp;
814 unsigned long addr;
815 unsigned long size;
816 struct file * file;
817 int err;
818 unsigned long flags;
819 unsigned long prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 int acc_mode;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800821 unsigned long user_addr;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700822 struct ipc_namespace *ns;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800823 struct shm_file_data *sfd;
824 struct path path;
Al Viroaeb5d722008-09-02 15:28:45 -0400825 fmode_t f_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800827 err = -EINVAL;
828 if (shmid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 goto out;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800830 else if ((addr = (ulong)shmaddr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 if (addr & (SHMLBA-1)) {
832 if (shmflg & SHM_RND)
833 addr &= ~(SHMLBA-1); /* round down */
834 else
835#ifndef __ARCH_FORCE_SHMLBA
836 if (addr & ~PAGE_MASK)
837#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800838 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 }
840 flags = MAP_SHARED | MAP_FIXED;
841 } else {
842 if ((shmflg & SHM_REMAP))
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800843 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844
845 flags = MAP_SHARED;
846 }
847
848 if (shmflg & SHM_RDONLY) {
849 prot = PROT_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850 acc_mode = S_IRUGO;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800851 f_mode = FMODE_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 } else {
853 prot = PROT_READ | PROT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 acc_mode = S_IRUGO | S_IWUGO;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800855 f_mode = FMODE_READ | FMODE_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 }
857 if (shmflg & SHM_EXEC) {
858 prot |= PROT_EXEC;
859 acc_mode |= S_IXUGO;
860 }
861
862 /*
863 * We cannot rely on the fs check since SYSV IPC does have an
864 * additional creator id...
865 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700866 ns = current->nsproxy->ipc_ns;
Nadia Derbey023a5352007-10-18 23:40:51 -0700867 shp = shm_lock_check(ns, shmid);
868 if (IS_ERR(shp)) {
869 err = PTR_ERR(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 goto out;
Nadia Derbey023a5352007-10-18 23:40:51 -0700871 }
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800872
873 err = -EACCES;
874 if (ipcperms(&shp->shm_perm, acc_mode))
875 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876
877 err = security_shm_shmat(shp, shmaddr, shmflg);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800878 if (err)
879 goto out_unlock;
880
Al Viro2c48b9c2009-08-09 00:52:35 +0400881 path = shp->shm_file->f_path;
882 path_get(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 shp->shm_nattch++;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800884 size = i_size_read(path.dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 shm_unlock(shp);
886
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800887 err = -ENOMEM;
888 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
889 if (!sfd)
Dave Hansence8d2cd2007-10-16 23:31:13 -0700890 goto out_put_dentry;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800891
Al Viro2c48b9c2009-08-09 00:52:35 +0400892 file = alloc_file(&path, f_mode,
893 is_file_hugepages(shp->shm_file) ?
Al Viroc4caa772009-11-30 08:38:43 -0500894 &shm_file_operations_huge :
895 &shm_file_operations);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800896 if (!file)
897 goto out_free;
898
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800899 file->private_data = sfd;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800900 file->f_mapping = shp->shm_file->f_mapping;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700901 sfd->id = shp->shm_perm.id;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800902 sfd->ns = get_ipc_ns(ns);
903 sfd->file = shp->shm_file;
904 sfd->vm_ops = NULL;
905
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 down_write(&current->mm->mmap_sem);
907 if (addr && !(shmflg & SHM_REMAP)) {
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800908 err = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909 if (find_vma_intersection(current->mm, addr, addr + size))
910 goto invalid;
911 /*
912 * If shm segment goes below stack, make sure there is some
913 * space left for the stack to grow (at least 4 pages).
914 */
915 if (addr < current->mm->start_stack &&
916 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
917 goto invalid;
918 }
919
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800920 user_addr = do_mmap (file, addr, size, prot, flags, 0);
921 *raddr = user_addr;
922 err = 0;
923 if (IS_ERR_VALUE(user_addr))
924 err = (long)user_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925invalid:
926 up_write(&current->mm->mmap_sem);
927
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800928 fput(file);
929
930out_nattch:
Nadia Derbey3e148c72007-10-18 23:40:54 -0700931 down_write(&shm_ids(ns).rw_mutex);
Nadia Derbey00c2bf82008-07-25 01:48:03 -0700932 shp = shm_lock(ns, shmid);
Nadia Derbey023a5352007-10-18 23:40:51 -0700933 BUG_ON(IS_ERR(shp));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934 shp->shm_nattch--;
935 if(shp->shm_nattch == 0 &&
Andrew Mortonb33291c2006-01-08 01:02:21 -0800936 shp->shm_perm.mode & SHM_DEST)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700937 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938 else
939 shm_unlock(shp);
Nadia Derbey3e148c72007-10-18 23:40:54 -0700940 up_write(&shm_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942out:
943 return err;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800944
945out_unlock:
946 shm_unlock(shp);
947 goto out;
948
949out_free:
950 kfree(sfd);
Dave Hansence8d2cd2007-10-16 23:31:13 -0700951out_put_dentry:
Al Viro2c48b9c2009-08-09 00:52:35 +0400952 path_put(&path);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800953 goto out_nattch;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954}
955
Heiko Carstensd5460c92009-01-14 14:14:27 +0100956SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -0700957{
958 unsigned long ret;
959 long err;
960
961 err = do_shmat(shmid, shmaddr, shmflg, &ret);
962 if (err)
963 return err;
964 force_successful_syscall_return();
965 return (long)ret;
966}
967
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968/*
969 * detach and kill segment if marked destroyed.
970 * The work is done in shm_close.
971 */
Heiko Carstensd5460c92009-01-14 14:14:27 +0100972SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973{
974 struct mm_struct *mm = current->mm;
Mike Frysinger586c7e62009-06-09 16:26:23 -0700975 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 unsigned long addr = (unsigned long)shmaddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 int retval = -EINVAL;
Mike Frysinger586c7e62009-06-09 16:26:23 -0700978#ifdef CONFIG_MMU
979 loff_t size = 0;
980 struct vm_area_struct *next;
981#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982
Hugh Dickinsdf1e2fb2006-03-24 03:18:06 -0800983 if (addr & ~PAGE_MASK)
984 return retval;
985
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 down_write(&mm->mmap_sem);
987
988 /*
989 * This function tries to be smart and unmap shm segments that
990 * were modified by partial mlock or munmap calls:
991 * - It first determines the size of the shm segment that should be
992 * unmapped: It searches for a vma that is backed by shm and that
993 * started at address shmaddr. It records it's size and then unmaps
994 * it.
995 * - Then it unmaps all shm vmas that started at shmaddr and that
996 * are within the initially determined size.
997 * Errors from do_munmap are ignored: the function only fails if
998 * it's called with invalid parameters or if it's called to unmap
999 * a part of a vma. Both calls in this function are for full vmas,
1000 * the parameters are directly copied from the vma itself and always
1001 * valid - therefore do_munmap cannot fail. (famous last words?)
1002 */
1003 /*
1004 * If it had been mremap()'d, the starting address would not
1005 * match the usual checks anyway. So assume all vma's are
1006 * above the starting address given.
1007 */
1008 vma = find_vma(mm, addr);
1009
David Howells8feae132009-01-08 12:04:47 +00001010#ifdef CONFIG_MMU
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 while (vma) {
1012 next = vma->vm_next;
1013
1014 /*
1015 * Check if the starting address would match, i.e. it's
1016 * a fragment created by mprotect() and/or munmap(), or it
1017 * otherwise it starts at this address with no hassles.
1018 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001019 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1021
1022
Josef Sipek6d630792006-12-08 02:37:11 -08001023 size = vma->vm_file->f_path.dentry->d_inode->i_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001024 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1025 /*
1026 * We discovered the size of the shm segment, so
1027 * break out of here and fall through to the next
1028 * loop that uses the size information to stop
1029 * searching for matching vma's.
1030 */
1031 retval = 0;
1032 vma = next;
1033 break;
1034 }
1035 vma = next;
1036 }
1037
1038 /*
1039 * We need look no further than the maximum address a fragment
1040 * could possibly have landed at. Also cast things to loff_t to
1041 * prevent overflows and make comparisions vs. equal-width types.
1042 */
KAMEZAWA Hiroyuki8e367092006-02-10 01:51:12 -08001043 size = PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001044 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1045 next = vma->vm_next;
1046
1047 /* finding a matching vma now does not alter retval */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001048 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001049 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1050
1051 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1052 vma = next;
1053 }
1054
David Howells8feae132009-01-08 12:04:47 +00001055#else /* CONFIG_MMU */
1056 /* under NOMMU conditions, the exact address to be destroyed must be
1057 * given */
1058 retval = -EINVAL;
1059 if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1060 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1061 retval = 0;
1062 }
1063
1064#endif
1065
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066 up_write(&mm->mmap_sem);
1067 return retval;
1068}
1069
1070#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -07001071static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072{
Mike Waychison19b49462005-09-06 15:17:10 -07001073 struct shmid_kernel *shp = it;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074
Paul Menage6c826812008-06-12 15:21:49 -07001075#if BITS_PER_LONG <= 32
1076#define SIZE_SPEC "%10lu"
1077#else
1078#define SIZE_SPEC "%21lu"
1079#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080
Paul Menage6c826812008-06-12 15:21:49 -07001081 return seq_printf(s,
1082 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1083 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n",
Mike Waychison19b49462005-09-06 15:17:10 -07001084 shp->shm_perm.key,
Nadia Derbey7ca7e562007-10-18 23:40:48 -07001085 shp->shm_perm.id,
Andrew Mortonb33291c2006-01-08 01:02:21 -08001086 shp->shm_perm.mode,
Mike Waychison19b49462005-09-06 15:17:10 -07001087 shp->shm_segsz,
1088 shp->shm_cprid,
1089 shp->shm_lprid,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001090 shp->shm_nattch,
Mike Waychison19b49462005-09-06 15:17:10 -07001091 shp->shm_perm.uid,
1092 shp->shm_perm.gid,
1093 shp->shm_perm.cuid,
1094 shp->shm_perm.cgid,
1095 shp->shm_atim,
1096 shp->shm_dtim,
1097 shp->shm_ctim);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098}
1099#endif