blob: e636910454a9b80ab9216498b09002c86d93e088 [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 Rothwell7d87e142005-05-01 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 Rothwell7d87e142005-05-01 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -070057static struct vm_operations_struct shm_vm_ops;
58
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)
Nadia Derbey1b531f22007-10-18 23:40:55 -070063#define shm_buildid(id, seq) ipc_buildid(id, seq)
Kirill Korotaev4e982312006-10-02 02:18:22 -070064
Nadia Derbey7748dbf2007-10-18 23:40:49 -070065static int newseg(struct ipc_namespace *, struct ipc_params *);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080066static void shm_open(struct vm_area_struct *vma);
67static void shm_close(struct vm_area_struct *vma);
Kirill Korotaev4e982312006-10-02 02:18:22 -070068static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -070069#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -070070static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071#endif
72
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080073void shm_init_ns(struct ipc_namespace *ns)
Kirill Korotaev4e982312006-10-02 02:18:22 -070074{
Kirill Korotaev4e982312006-10-02 02:18:22 -070075 ns->shm_ctlmax = SHMMAX;
76 ns->shm_ctlall = SHMALL;
77 ns->shm_ctlmni = SHMMNI;
78 ns->shm_tot = 0;
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080079 ipc_init_ids(&ns->ids[IPC_SHM_IDS]);
Kirill Korotaev4e982312006-10-02 02:18:22 -070080}
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
Nadia Derbeyf4566f02007-10-18 23:40:53 -070082/*
Nadia Derbey3e148c72007-10-18 23:40:54 -070083 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
84 * Only shm_ids.rw_mutex remains locked on exit.
Nadia Derbeyf4566f02007-10-18 23:40:53 -070085 */
Pierre Peiffer01b8b072008-02-08 04:18:57 -080086static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
Kirill Korotaev4e982312006-10-02 02:18:22 -070087{
Pierre Peiffer01b8b072008-02-08 04:18:57 -080088 struct shmid_kernel *shp;
89 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
90
Kirill Korotaev4e982312006-10-02 02:18:22 -070091 if (shp->shm_nattch){
92 shp->shm_perm.mode |= SHM_DEST;
93 /* Do not find it any more */
94 shp->shm_perm.key = IPC_PRIVATE;
95 shm_unlock(shp);
96 } else
97 shm_destroy(ns, shp);
98}
99
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800100#ifdef CONFIG_IPC_NS
Kirill Korotaev4e982312006-10-02 02:18:22 -0700101void shm_exit_ns(struct ipc_namespace *ns)
102{
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800103 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
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/*
116 * shm_lock_(check_)down routines are called in the paths where the rw_mutex
117 * is held to protect access to the idr tree.
118 */
119static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns,
120 int id)
121{
122 struct kern_ipc_perm *ipcp = ipc_lock_down(&shm_ids(ns), id);
123
Pierre Peifferb1ed88b2008-02-06 01:36:23 -0800124 if (IS_ERR(ipcp))
125 return (struct shmid_kernel *)ipcp;
126
Nadia Derbey3e148c72007-10-18 23:40:54 -0700127 return container_of(ipcp, struct shmid_kernel, shm_perm);
128}
129
130static inline struct shmid_kernel *shm_lock_check_down(
131 struct ipc_namespace *ns,
132 int id)
133{
134 struct kern_ipc_perm *ipcp = ipc_lock_check_down(&shm_ids(ns), id);
135
Pierre Peifferb1ed88b2008-02-06 01:36:23 -0800136 if (IS_ERR(ipcp))
137 return (struct shmid_kernel *)ipcp;
138
Nadia Derbey3e148c72007-10-18 23:40:54 -0700139 return container_of(ipcp, struct shmid_kernel, shm_perm);
140}
141
142/*
143 * shm_lock_(check_) routines are called in the paths where the rw_mutex
144 * is not held.
145 */
Nadia Derbey023a5352007-10-18 23:40:51 -0700146static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700148 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
149
Pierre Peifferb1ed88b2008-02-06 01:36:23 -0800150 if (IS_ERR(ipcp))
151 return (struct shmid_kernel *)ipcp;
152
Nadia Derbey03f02c72007-10-18 23:40:51 -0700153 return container_of(ipcp, struct shmid_kernel, shm_perm);
Nadia Derbey023a5352007-10-18 23:40:51 -0700154}
155
156static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
157 int id)
158{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700159 struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
160
Pierre Peifferb1ed88b2008-02-06 01:36:23 -0800161 if (IS_ERR(ipcp))
162 return (struct shmid_kernel *)ipcp;
163
Nadia Derbey03f02c72007-10-18 23:40:51 -0700164 return container_of(ipcp, struct shmid_kernel, shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165}
166
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700167static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700169 ipc_rmid(&shm_ids(ns), &s->shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170}
171
Kirill Korotaev4e982312006-10-02 02:18:22 -0700172static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700174 return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175}
176
177
178
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800179/* This is called by fork, once for every shm attach. */
180static void shm_open(struct vm_area_struct *vma)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700181{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800182 struct file *file = vma->vm_file;
183 struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 struct shmid_kernel *shp;
185
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800186 shp = shm_lock(sfd->ns, sfd->id);
Nadia Derbey023a5352007-10-18 23:40:51 -0700187 BUG_ON(IS_ERR(shp));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 shp->shm_atim = get_seconds();
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700189 shp->shm_lprid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 shp->shm_nattch++;
191 shm_unlock(shp);
192}
193
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194/*
195 * shm_destroy - free the struct shmid_kernel
196 *
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700197 * @ns: namespace
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 * @shp: struct to free
199 *
Nadia Derbey3e148c72007-10-18 23:40:54 -0700200 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 * but returns with shp unlocked and freed.
202 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700203static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700205 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700206 shm_rmid(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 shm_unlock(shp);
208 if (!is_file_hugepages(shp->shm_file))
209 shmem_lock(shp->shm_file, 0, shp->mlock_user);
210 else
Josef Sipek6d630792006-12-08 02:37:11 -0800211 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 shp->mlock_user);
213 fput (shp->shm_file);
214 security_shm_free(shp);
215 ipc_rcu_putref(shp);
216}
217
218/*
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800219 * remove the attach descriptor vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 * free memory for segment if it is marked destroyed.
221 * The descriptor has already been removed from the current->mm->mmap list
222 * and will later be kfree()d.
223 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800224static void shm_close(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800226 struct file * file = vma->vm_file;
227 struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 struct shmid_kernel *shp;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800229 struct ipc_namespace *ns = sfd->ns;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700230
Nadia Derbey3e148c72007-10-18 23:40:54 -0700231 down_write(&shm_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 /* remove from the list of attaches of the shm segment */
Nadia Derbey3e148c72007-10-18 23:40:54 -0700233 shp = shm_lock_down(ns, sfd->id);
Nadia Derbey023a5352007-10-18 23:40:51 -0700234 BUG_ON(IS_ERR(shp));
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700235 shp->shm_lprid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 shp->shm_dtim = get_seconds();
237 shp->shm_nattch--;
238 if(shp->shm_nattch == 0 &&
Andrew Mortonb33291c2006-01-08 01:02:21 -0800239 shp->shm_perm.mode & SHM_DEST)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700240 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 else
242 shm_unlock(shp);
Nadia Derbey3e148c72007-10-18 23:40:54 -0700243 up_write(&shm_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244}
245
Nick Piggind0217ac2007-07-19 01:47:03 -0700246static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800247{
248 struct file *file = vma->vm_file;
249 struct shm_file_data *sfd = shm_file_data(file);
250
Nick Piggind0217ac2007-07-19 01:47:03 -0700251 return sfd->vm_ops->fault(vma, vmf);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800252}
253
254#ifdef CONFIG_NUMA
Adrian Bunkd823e3e2007-10-16 23:26:42 -0700255static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800256{
257 struct file *file = vma->vm_file;
258 struct shm_file_data *sfd = shm_file_data(file);
259 int err = 0;
260 if (sfd->vm_ops->set_policy)
261 err = sfd->vm_ops->set_policy(vma, new);
262 return err;
263}
264
Adrian Bunkd823e3e2007-10-16 23:26:42 -0700265static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
266 unsigned long addr)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800267{
268 struct file *file = vma->vm_file;
269 struct shm_file_data *sfd = shm_file_data(file);
270 struct mempolicy *pol = NULL;
271
272 if (sfd->vm_ops->get_policy)
273 pol = sfd->vm_ops->get_policy(vma, addr);
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -0700274 else if (vma->vm_policy)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800275 pol = vma->vm_policy;
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -0700276
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800277 return pol;
278}
279#endif
280
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281static int shm_mmap(struct file * file, struct vm_area_struct * vma)
282{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800283 struct shm_file_data *sfd = shm_file_data(file);
David Howellsb0e15192006-01-06 00:11:42 -0800284 int ret;
285
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800286 ret = sfd->file->f_op->mmap(sfd->file, vma);
287 if (ret != 0)
288 return ret;
289 sfd->vm_ops = vma->vm_ops;
David Howells2e92a3b2007-07-31 00:37:24 -0700290#ifdef CONFIG_MMU
Nick Piggin54cb8822007-07-19 01:46:59 -0700291 BUG_ON(!sfd->vm_ops->fault);
David Howells2e92a3b2007-07-31 00:37:24 -0700292#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800293 vma->vm_ops = &shm_vm_ops;
294 shm_open(vma);
David Howellsb0e15192006-01-06 00:11:42 -0800295
296 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297}
298
Kirill Korotaev4e982312006-10-02 02:18:22 -0700299static int shm_release(struct inode *ino, struct file *file)
300{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800301 struct shm_file_data *sfd = shm_file_data(file);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700302
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800303 put_ipc_ns(sfd->ns);
304 shm_file_data(file) = NULL;
305 kfree(sfd);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700306 return 0;
307}
308
Adam Litke516dffd2007-03-01 15:46:08 -0800309static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
310{
311 int (*fsync) (struct file *, struct dentry *, int datasync);
312 struct shm_file_data *sfd = shm_file_data(file);
313 int ret = -EINVAL;
314
315 fsync = sfd->file->f_op->fsync;
316 if (fsync)
317 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
318 return ret;
319}
320
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800321static unsigned long shm_get_unmapped_area(struct file *file,
322 unsigned long addr, unsigned long len, unsigned long pgoff,
323 unsigned long flags)
324{
325 struct shm_file_data *sfd = shm_file_data(file);
Adam Litke516dffd2007-03-01 15:46:08 -0800326 return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800327}
Adam Litke516dffd2007-03-01 15:46:08 -0800328
329int is_file_shm_hugepages(struct file *file)
330{
331 int ret = 0;
332
333 if (file->f_op == &shm_file_operations) {
334 struct shm_file_data *sfd;
335 sfd = shm_file_data(file);
336 ret = is_file_hugepages(sfd->file);
337 }
338 return ret;
339}
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800340
Arjan van de Ven9a321442007-02-12 00:55:35 -0800341static const struct file_operations shm_file_operations = {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700342 .mmap = shm_mmap,
Adam Litke516dffd2007-03-01 15:46:08 -0800343 .fsync = shm_fsync,
Kirill Korotaev4e982312006-10-02 02:18:22 -0700344 .release = shm_release,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800345 .get_unmapped_area = shm_get_unmapped_area,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346};
347
348static struct vm_operations_struct shm_vm_ops = {
349 .open = shm_open, /* callback for a new vm-area open */
350 .close = shm_close, /* callback for when the vm-area is released */
Nick Piggin54cb8822007-07-19 01:46:59 -0700351 .fault = shm_fault,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800352#if defined(CONFIG_NUMA)
353 .set_policy = shm_set_policy,
354 .get_policy = shm_get_policy,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355#endif
356};
357
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700358/**
359 * newseg - Create a new shared memory segment
360 * @ns: namespace
361 * @params: ptr to the structure that contains key, size and shmflg
362 *
Nadia Derbey3e148c72007-10-18 23:40:54 -0700363 * Called with shm_ids.rw_mutex held as a writer.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700364 */
365
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700366static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367{
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700368 key_t key = params->key;
369 int shmflg = params->flg;
370 size_t size = params->u.size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 int error;
372 struct shmid_kernel *shp;
373 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
374 struct file * file;
375 char name[13];
376 int id;
377
Kirill Korotaev4e982312006-10-02 02:18:22 -0700378 if (size < SHMMIN || size > ns->shm_ctlmax)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 return -EINVAL;
380
Guy Streeterf66d45e2007-01-23 12:20:04 -0600381 if (ns->shm_tot + numpages > ns->shm_ctlall)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 return -ENOSPC;
383
384 shp = ipc_rcu_alloc(sizeof(*shp));
385 if (!shp)
386 return -ENOMEM;
387
388 shp->shm_perm.key = key;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800389 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 shp->mlock_user = NULL;
391
392 shp->shm_perm.security = NULL;
393 error = security_shm_alloc(shp);
394 if (error) {
395 ipc_rcu_putref(shp);
396 return error;
397 }
398
Eric W. Biederman9d665862007-06-16 10:16:16 -0700399 sprintf (name, "SYSV%08x", key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 if (shmflg & SHM_HUGETLB) {
Eric W. Biederman9d665862007-06-16 10:16:16 -0700401 /* hugetlb_file_setup takes care of mlock user accounting */
402 file = hugetlb_file_setup(name, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 shp->mlock_user = current->user;
404 } else {
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800405 int acctflag = VM_ACCOUNT;
406 /*
407 * Do not allow no accounting for OVERCOMMIT_NEVER, even
408 * if it's asked for.
409 */
410 if ((shmflg & SHM_NORESERVE) &&
411 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
412 acctflag = 0;
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800413 file = shmem_file_setup(name, size, acctflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 }
415 error = PTR_ERR(file);
416 if (IS_ERR(file))
417 goto no_file;
418
Kirill Korotaev4e982312006-10-02 02:18:22 -0700419 id = shm_addid(ns, shp);
Pierre Peiffer283bb7f2007-10-18 23:40:57 -0700420 if (id < 0) {
421 error = id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 goto no_id;
Pierre Peiffer283bb7f2007-10-18 23:40:57 -0700423 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700425 shp->shm_cprid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 shp->shm_lprid = 0;
427 shp->shm_atim = shp->shm_dtim = 0;
428 shp->shm_ctim = get_seconds();
429 shp->shm_segsz = size;
430 shp->shm_nattch = 0;
Nadia Derbey1b531f22007-10-18 23:40:55 -0700431 shp->shm_perm.id = shm_buildid(id, shp->shm_perm.seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 shp->shm_file = file;
Badari Pulavarty30475cc2007-06-16 10:15:59 -0700433 /*
434 * shmid gets reported as "inode#" in /proc/pid/maps.
435 * proc-ps tools use this. Changing this will break them.
436 */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700437 file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
Krishnakumar R551110a2005-10-29 18:16:45 -0700438
Kirill Korotaev4e982312006-10-02 02:18:22 -0700439 ns->shm_tot += numpages;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700440 error = shp->shm_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 shm_unlock(shp);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700442 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443
444no_id:
445 fput(file);
446no_file:
447 security_shm_free(shp);
448 ipc_rcu_putref(shp);
449 return error;
450}
451
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700452/*
Nadia Derbey3e148c72007-10-18 23:40:54 -0700453 * Called with shm_ids.rw_mutex and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700454 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700455static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700456{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700457 struct shmid_kernel *shp;
458
459 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
460 return security_shm_associate(shp, shmflg);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700461}
462
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700463/*
Nadia Derbey3e148c72007-10-18 23:40:54 -0700464 * Called with shm_ids.rw_mutex and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700465 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700466static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
467 struct ipc_params *params)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700468{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700469 struct shmid_kernel *shp;
470
471 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
472 if (shp->shm_segsz < params->u.size)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700473 return -EINVAL;
474
475 return 0;
476}
477
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
479{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700480 struct ipc_namespace *ns;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700481 struct ipc_ops shm_ops;
482 struct ipc_params shm_params;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483
Kirill Korotaev4e982312006-10-02 02:18:22 -0700484 ns = current->nsproxy->ipc_ns;
485
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700486 shm_ops.getnew = newseg;
487 shm_ops.associate = shm_security;
488 shm_ops.more_checks = shm_more_checks;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700489
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700490 shm_params.key = key;
491 shm_params.flg = shmflg;
492 shm_params.u.size = size;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700493
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700494 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495}
496
497static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
498{
499 switch(version) {
500 case IPC_64:
501 return copy_to_user(buf, in, sizeof(*in));
502 case IPC_OLD:
503 {
504 struct shmid_ds out;
505
506 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
507 out.shm_segsz = in->shm_segsz;
508 out.shm_atime = in->shm_atime;
509 out.shm_dtime = in->shm_dtime;
510 out.shm_ctime = in->shm_ctime;
511 out.shm_cpid = in->shm_cpid;
512 out.shm_lpid = in->shm_lpid;
513 out.shm_nattch = in->shm_nattch;
514
515 return copy_to_user(buf, &out, sizeof(out));
516 }
517 default:
518 return -EINVAL;
519 }
520}
521
522struct shm_setbuf {
523 uid_t uid;
524 gid_t gid;
525 mode_t mode;
526};
527
528static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
529{
530 switch(version) {
531 case IPC_64:
532 {
533 struct shmid64_ds tbuf;
534
535 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
536 return -EFAULT;
537
538 out->uid = tbuf.shm_perm.uid;
539 out->gid = tbuf.shm_perm.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800540 out->mode = tbuf.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541
542 return 0;
543 }
544 case IPC_OLD:
545 {
546 struct shmid_ds tbuf_old;
547
548 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
549 return -EFAULT;
550
551 out->uid = tbuf_old.shm_perm.uid;
552 out->gid = tbuf_old.shm_perm.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800553 out->mode = tbuf_old.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554
555 return 0;
556 }
557 default:
558 return -EINVAL;
559 }
560}
561
562static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
563{
564 switch(version) {
565 case IPC_64:
566 return copy_to_user(buf, in, sizeof(*in));
567 case IPC_OLD:
568 {
569 struct shminfo out;
570
571 if(in->shmmax > INT_MAX)
572 out.shmmax = INT_MAX;
573 else
574 out.shmmax = (int)in->shmmax;
575
576 out.shmmin = in->shmmin;
577 out.shmmni = in->shmmni;
578 out.shmseg = in->shmseg;
579 out.shmall = in->shmall;
580
581 return copy_to_user(buf, &out, sizeof(out));
582 }
583 default:
584 return -EINVAL;
585 }
586}
587
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700588/*
Nadia Derbey3e148c72007-10-18 23:40:54 -0700589 * Called with shm_ids.rw_mutex held as a reader
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700590 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700591static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
592 unsigned long *swp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700594 int next_id;
595 int total, in_use;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596
597 *rss = 0;
598 *swp = 0;
599
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700600 in_use = shm_ids(ns).in_use;
601
602 for (total = 0, next_id = 0; total < in_use; next_id++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 struct shmid_kernel *shp;
604 struct inode *inode;
605
Nadia Derbey637c3662007-10-18 23:40:50 -0700606 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700607 if (shp == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 continue;
609
Josef Sipek6d630792006-12-08 02:37:11 -0800610 inode = shp->shm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611
612 if (is_file_hugepages(shp->shm_file)) {
613 struct address_space *mapping = inode->i_mapping;
614 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
615 } else {
616 struct shmem_inode_info *info = SHMEM_I(inode);
617 spin_lock(&info->lock);
618 *rss += inode->i_mapping->nrpages;
619 *swp += info->swapped;
620 spin_unlock(&info->lock);
621 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700622
623 total++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 }
625}
626
627asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
628{
629 struct shm_setbuf setbuf;
630 struct shmid_kernel *shp;
631 int err, version;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700632 struct ipc_namespace *ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633
634 if (cmd < 0 || shmid < 0) {
635 err = -EINVAL;
636 goto out;
637 }
638
639 version = ipc_parse_version(&cmd);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700640 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641
642 switch (cmd) { /* replace with proc interface ? */
643 case IPC_INFO:
644 {
645 struct shminfo64 shminfo;
646
647 err = security_shm_shmctl(NULL, cmd);
648 if (err)
649 return err;
650
651 memset(&shminfo,0,sizeof(shminfo));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700652 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
653 shminfo.shmmax = ns->shm_ctlmax;
654 shminfo.shmall = ns->shm_ctlall;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655
656 shminfo.shmmin = SHMMIN;
657 if(copy_shminfo_to_user (buf, &shminfo, version))
658 return -EFAULT;
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700659
Nadia Derbey3e148c72007-10-18 23:40:54 -0700660 down_read(&shm_ids(ns).rw_mutex);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700661 err = ipc_get_maxid(&shm_ids(ns));
Nadia Derbey3e148c72007-10-18 23:40:54 -0700662 up_read(&shm_ids(ns).rw_mutex);
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700663
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 if(err<0)
665 err = 0;
666 goto out;
667 }
668 case SHM_INFO:
669 {
670 struct shm_info shm_info;
671
672 err = security_shm_shmctl(NULL, cmd);
673 if (err)
674 return err;
675
676 memset(&shm_info,0,sizeof(shm_info));
Nadia Derbey3e148c72007-10-18 23:40:54 -0700677 down_read(&shm_ids(ns).rw_mutex);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700678 shm_info.used_ids = shm_ids(ns).in_use;
679 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
680 shm_info.shm_tot = ns->shm_tot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 shm_info.swap_attempts = 0;
682 shm_info.swap_successes = 0;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700683 err = ipc_get_maxid(&shm_ids(ns));
Nadia Derbey3e148c72007-10-18 23:40:54 -0700684 up_read(&shm_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
686 err = -EFAULT;
687 goto out;
688 }
689
690 err = err < 0 ? 0 : err;
691 goto out;
692 }
693 case SHM_STAT:
694 case IPC_STAT:
695 {
696 struct shmid64_ds tbuf;
697 int result;
Nadia Derbey023a5352007-10-18 23:40:51 -0700698
699 if (!buf) {
700 err = -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 goto out;
Nadia Derbey023a5352007-10-18 23:40:51 -0700702 }
703
704 if (cmd == SHM_STAT) {
705 shp = shm_lock(ns, shmid);
706 if (IS_ERR(shp)) {
707 err = PTR_ERR(shp);
708 goto out;
709 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700710 result = shp->shm_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 } else {
Nadia Derbey023a5352007-10-18 23:40:51 -0700712 shp = shm_lock_check(ns, shmid);
713 if (IS_ERR(shp)) {
714 err = PTR_ERR(shp);
715 goto out;
716 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 result = 0;
718 }
719 err=-EACCES;
720 if (ipcperms (&shp->shm_perm, S_IRUGO))
721 goto out_unlock;
722 err = security_shm_shmctl(shp, cmd);
723 if (err)
724 goto out_unlock;
Nadia Derbey023a5352007-10-18 23:40:51 -0700725 memset(&tbuf, 0, sizeof(tbuf));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
727 tbuf.shm_segsz = shp->shm_segsz;
728 tbuf.shm_atime = shp->shm_atim;
729 tbuf.shm_dtime = shp->shm_dtim;
730 tbuf.shm_ctime = shp->shm_ctim;
731 tbuf.shm_cpid = shp->shm_cprid;
732 tbuf.shm_lpid = shp->shm_lprid;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800733 tbuf.shm_nattch = shp->shm_nattch;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 shm_unlock(shp);
735 if(copy_shmid_to_user (buf, &tbuf, version))
736 err = -EFAULT;
737 else
738 err = result;
739 goto out;
740 }
741 case SHM_LOCK:
742 case SHM_UNLOCK:
743 {
Nadia Derbey023a5352007-10-18 23:40:51 -0700744 shp = shm_lock_check(ns, shmid);
745 if (IS_ERR(shp)) {
746 err = PTR_ERR(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 goto out;
748 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749
Steve Grubb073115d2006-04-02 17:07:33 -0400750 err = audit_ipc_obj(&(shp->shm_perm));
751 if (err)
752 goto out_unlock;
753
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 if (!capable(CAP_IPC_LOCK)) {
755 err = -EPERM;
756 if (current->euid != shp->shm_perm.uid &&
757 current->euid != shp->shm_perm.cuid)
758 goto out_unlock;
759 if (cmd == SHM_LOCK &&
760 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
761 goto out_unlock;
762 }
763
764 err = security_shm_shmctl(shp, cmd);
765 if (err)
766 goto out_unlock;
767
768 if(cmd==SHM_LOCK) {
769 struct user_struct * user = current->user;
770 if (!is_file_hugepages(shp->shm_file)) {
771 err = shmem_lock(shp->shm_file, 1, user);
Pavel Emelianov7be77e22007-07-31 00:38:48 -0700772 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
Andrew Mortonb33291c2006-01-08 01:02:21 -0800773 shp->shm_perm.mode |= SHM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 shp->mlock_user = user;
775 }
776 }
777 } else if (!is_file_hugepages(shp->shm_file)) {
778 shmem_lock(shp->shm_file, 0, shp->mlock_user);
Andrew Mortonb33291c2006-01-08 01:02:21 -0800779 shp->shm_perm.mode &= ~SHM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 shp->mlock_user = NULL;
781 }
782 shm_unlock(shp);
783 goto out;
784 }
785 case IPC_RMID:
786 {
787 /*
788 * We cannot simply remove the file. The SVID states
789 * that the block remains until the last person
790 * detaches from it, then is deleted. A shmat() on
791 * an RMID segment is legal in older Linux and if
792 * we change it apps break...
793 *
794 * Instead we set a destroyed flag, and then blow
795 * the name away when the usage hits zero.
796 */
Nadia Derbey3e148c72007-10-18 23:40:54 -0700797 down_write(&shm_ids(ns).rw_mutex);
798 shp = shm_lock_check_down(ns, shmid);
Nadia Derbey023a5352007-10-18 23:40:51 -0700799 if (IS_ERR(shp)) {
800 err = PTR_ERR(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 goto out_up;
Nadia Derbey023a5352007-10-18 23:40:51 -0700802 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803
Steve Grubb073115d2006-04-02 17:07:33 -0400804 err = audit_ipc_obj(&(shp->shm_perm));
805 if (err)
806 goto out_unlock_up;
807
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 if (current->euid != shp->shm_perm.uid &&
809 current->euid != shp->shm_perm.cuid &&
810 !capable(CAP_SYS_ADMIN)) {
811 err=-EPERM;
812 goto out_unlock_up;
813 }
814
815 err = security_shm_shmctl(shp, cmd);
816 if (err)
817 goto out_unlock_up;
818
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800819 do_shm_rmid(ns, &shp->shm_perm);
Nadia Derbey3e148c72007-10-18 23:40:54 -0700820 up_write(&shm_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 goto out;
822 }
823
824 case IPC_SET:
825 {
Nadia Derbey023a5352007-10-18 23:40:51 -0700826 if (!buf) {
827 err = -EFAULT;
828 goto out;
829 }
830
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 if (copy_shmid_from_user (&setbuf, buf, version)) {
832 err = -EFAULT;
833 goto out;
834 }
Nadia Derbey3e148c72007-10-18 23:40:54 -0700835 down_write(&shm_ids(ns).rw_mutex);
836 shp = shm_lock_check_down(ns, shmid);
Nadia Derbey023a5352007-10-18 23:40:51 -0700837 if (IS_ERR(shp)) {
838 err = PTR_ERR(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 goto out_up;
Nadia Derbey023a5352007-10-18 23:40:51 -0700840 }
Steve Grubb073115d2006-04-02 17:07:33 -0400841 err = audit_ipc_obj(&(shp->shm_perm));
842 if (err)
843 goto out_unlock_up;
Linda Knippersac032212006-05-16 22:03:48 -0400844 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
Steve Grubb073115d2006-04-02 17:07:33 -0400845 if (err)
846 goto out_unlock_up;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 err=-EPERM;
848 if (current->euid != shp->shm_perm.uid &&
849 current->euid != shp->shm_perm.cuid &&
850 !capable(CAP_SYS_ADMIN)) {
851 goto out_unlock_up;
852 }
853
854 err = security_shm_shmctl(shp, cmd);
855 if (err)
856 goto out_unlock_up;
857
858 shp->shm_perm.uid = setbuf.uid;
859 shp->shm_perm.gid = setbuf.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800860 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 | (setbuf.mode & S_IRWXUGO);
862 shp->shm_ctim = get_seconds();
863 break;
864 }
865
866 default:
867 err = -EINVAL;
868 goto out;
869 }
870
871 err = 0;
872out_unlock_up:
873 shm_unlock(shp);
874out_up:
Nadia Derbey3e148c72007-10-18 23:40:54 -0700875 up_write(&shm_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 goto out;
877out_unlock:
878 shm_unlock(shp);
879out:
880 return err;
881}
882
883/*
884 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
885 *
886 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
887 * "raddr" thing points to kernel space, and there has to be a wrapper around
888 * this.
889 */
890long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
891{
892 struct shmid_kernel *shp;
893 unsigned long addr;
894 unsigned long size;
895 struct file * file;
896 int err;
897 unsigned long flags;
898 unsigned long prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899 int acc_mode;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800900 unsigned long user_addr;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700901 struct ipc_namespace *ns;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800902 struct shm_file_data *sfd;
903 struct path path;
904 mode_t f_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800906 err = -EINVAL;
907 if (shmid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908 goto out;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800909 else if ((addr = (ulong)shmaddr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 if (addr & (SHMLBA-1)) {
911 if (shmflg & SHM_RND)
912 addr &= ~(SHMLBA-1); /* round down */
913 else
914#ifndef __ARCH_FORCE_SHMLBA
915 if (addr & ~PAGE_MASK)
916#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800917 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 }
919 flags = MAP_SHARED | MAP_FIXED;
920 } else {
921 if ((shmflg & SHM_REMAP))
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800922 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923
924 flags = MAP_SHARED;
925 }
926
927 if (shmflg & SHM_RDONLY) {
928 prot = PROT_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929 acc_mode = S_IRUGO;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800930 f_mode = FMODE_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 } else {
932 prot = PROT_READ | PROT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 acc_mode = S_IRUGO | S_IWUGO;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800934 f_mode = FMODE_READ | FMODE_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 }
936 if (shmflg & SHM_EXEC) {
937 prot |= PROT_EXEC;
938 acc_mode |= S_IXUGO;
939 }
940
941 /*
942 * We cannot rely on the fs check since SYSV IPC does have an
943 * additional creator id...
944 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700945 ns = current->nsproxy->ipc_ns;
Nadia Derbey023a5352007-10-18 23:40:51 -0700946 shp = shm_lock_check(ns, shmid);
947 if (IS_ERR(shp)) {
948 err = PTR_ERR(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949 goto out;
Nadia Derbey023a5352007-10-18 23:40:51 -0700950 }
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800951
952 err = -EACCES;
953 if (ipcperms(&shp->shm_perm, acc_mode))
954 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955
956 err = security_shm_shmat(shp, shmaddr, shmflg);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800957 if (err)
958 goto out_unlock;
959
960 path.dentry = dget(shp->shm_file->f_path.dentry);
Dave Hansence8d2cd2007-10-16 23:31:13 -0700961 path.mnt = shp->shm_file->f_path.mnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 shp->shm_nattch++;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800963 size = i_size_read(path.dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 shm_unlock(shp);
965
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800966 err = -ENOMEM;
967 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
968 if (!sfd)
Dave Hansence8d2cd2007-10-16 23:31:13 -0700969 goto out_put_dentry;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800970
971 err = -ENOMEM;
Dave Hansence8d2cd2007-10-16 23:31:13 -0700972
973 file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800974 if (!file)
975 goto out_free;
976
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800977 file->private_data = sfd;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800978 file->f_mapping = shp->shm_file->f_mapping;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700979 sfd->id = shp->shm_perm.id;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800980 sfd->ns = get_ipc_ns(ns);
981 sfd->file = shp->shm_file;
982 sfd->vm_ops = NULL;
983
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984 down_write(&current->mm->mmap_sem);
985 if (addr && !(shmflg & SHM_REMAP)) {
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800986 err = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 if (find_vma_intersection(current->mm, addr, addr + size))
988 goto invalid;
989 /*
990 * If shm segment goes below stack, make sure there is some
991 * space left for the stack to grow (at least 4 pages).
992 */
993 if (addr < current->mm->start_stack &&
994 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
995 goto invalid;
996 }
997
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800998 user_addr = do_mmap (file, addr, size, prot, flags, 0);
999 *raddr = user_addr;
1000 err = 0;
1001 if (IS_ERR_VALUE(user_addr))
1002 err = (long)user_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003invalid:
1004 up_write(&current->mm->mmap_sem);
1005
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001006 fput(file);
1007
1008out_nattch:
Nadia Derbey3e148c72007-10-18 23:40:54 -07001009 down_write(&shm_ids(ns).rw_mutex);
1010 shp = shm_lock_down(ns, shmid);
Nadia Derbey023a5352007-10-18 23:40:51 -07001011 BUG_ON(IS_ERR(shp));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012 shp->shm_nattch--;
1013 if(shp->shm_nattch == 0 &&
Andrew Mortonb33291c2006-01-08 01:02:21 -08001014 shp->shm_perm.mode & SHM_DEST)
Kirill Korotaev4e982312006-10-02 02:18:22 -07001015 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016 else
1017 shm_unlock(shp);
Nadia Derbey3e148c72007-10-18 23:40:54 -07001018 up_write(&shm_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020out:
1021 return err;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001022
1023out_unlock:
1024 shm_unlock(shp);
1025 goto out;
1026
1027out_free:
1028 kfree(sfd);
Dave Hansence8d2cd2007-10-16 23:31:13 -07001029out_put_dentry:
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001030 dput(path.dentry);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001031 goto out_nattch;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032}
1033
Stephen Rothwell7d87e142005-05-01 08:59:12 -07001034asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
1035{
1036 unsigned long ret;
1037 long err;
1038
1039 err = do_shmat(shmid, shmaddr, shmflg, &ret);
1040 if (err)
1041 return err;
1042 force_successful_syscall_return();
1043 return (long)ret;
1044}
1045
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046/*
1047 * detach and kill segment if marked destroyed.
1048 * The work is done in shm_close.
1049 */
1050asmlinkage long sys_shmdt(char __user *shmaddr)
1051{
1052 struct mm_struct *mm = current->mm;
1053 struct vm_area_struct *vma, *next;
1054 unsigned long addr = (unsigned long)shmaddr;
1055 loff_t size = 0;
1056 int retval = -EINVAL;
1057
Hugh Dickinsdf1e2fb2006-03-24 03:18:06 -08001058 if (addr & ~PAGE_MASK)
1059 return retval;
1060
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061 down_write(&mm->mmap_sem);
1062
1063 /*
1064 * This function tries to be smart and unmap shm segments that
1065 * were modified by partial mlock or munmap calls:
1066 * - It first determines the size of the shm segment that should be
1067 * unmapped: It searches for a vma that is backed by shm and that
1068 * started at address shmaddr. It records it's size and then unmaps
1069 * it.
1070 * - Then it unmaps all shm vmas that started at shmaddr and that
1071 * are within the initially determined size.
1072 * Errors from do_munmap are ignored: the function only fails if
1073 * it's called with invalid parameters or if it's called to unmap
1074 * a part of a vma. Both calls in this function are for full vmas,
1075 * the parameters are directly copied from the vma itself and always
1076 * valid - therefore do_munmap cannot fail. (famous last words?)
1077 */
1078 /*
1079 * If it had been mremap()'d, the starting address would not
1080 * match the usual checks anyway. So assume all vma's are
1081 * above the starting address given.
1082 */
1083 vma = find_vma(mm, addr);
1084
1085 while (vma) {
1086 next = vma->vm_next;
1087
1088 /*
1089 * Check if the starting address would match, i.e. it's
1090 * a fragment created by mprotect() and/or munmap(), or it
1091 * otherwise it starts at this address with no hassles.
1092 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001093 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1095
1096
Josef Sipek6d630792006-12-08 02:37:11 -08001097 size = vma->vm_file->f_path.dentry->d_inode->i_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1099 /*
1100 * We discovered the size of the shm segment, so
1101 * break out of here and fall through to the next
1102 * loop that uses the size information to stop
1103 * searching for matching vma's.
1104 */
1105 retval = 0;
1106 vma = next;
1107 break;
1108 }
1109 vma = next;
1110 }
1111
1112 /*
1113 * We need look no further than the maximum address a fragment
1114 * could possibly have landed at. Also cast things to loff_t to
1115 * prevent overflows and make comparisions vs. equal-width types.
1116 */
KAMEZAWA Hiroyuki8e367092006-02-10 01:51:12 -08001117 size = PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1119 next = vma->vm_next;
1120
1121 /* finding a matching vma now does not alter retval */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001122 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1124
1125 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1126 vma = next;
1127 }
1128
1129 up_write(&mm->mmap_sem);
1130 return retval;
1131}
1132
1133#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -07001134static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135{
Mike Waychison19b49462005-09-06 15:17:10 -07001136 struct shmid_kernel *shp = it;
1137 char *format;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1140#define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141
Mike Waychison19b49462005-09-06 15:17:10 -07001142 if (sizeof(size_t) <= sizeof(int))
1143 format = SMALL_STRING;
1144 else
1145 format = BIG_STRING;
1146 return seq_printf(s, format,
1147 shp->shm_perm.key,
Nadia Derbey7ca7e562007-10-18 23:40:48 -07001148 shp->shm_perm.id,
Andrew Mortonb33291c2006-01-08 01:02:21 -08001149 shp->shm_perm.mode,
Mike Waychison19b49462005-09-06 15:17:10 -07001150 shp->shm_segsz,
1151 shp->shm_cprid,
1152 shp->shm_lprid,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001153 shp->shm_nattch,
Mike Waychison19b49462005-09-06 15:17:10 -07001154 shp->shm_perm.uid,
1155 shp->shm_perm.gid,
1156 shp->shm_perm.cuid,
1157 shp->shm_perm.cgid,
1158 shp->shm_atim,
1159 shp->shm_dtim,
1160 shp->shm_ctim);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161}
1162#endif