blob: 0852f206d8951cb4f53071b36e159ae0332e5093 [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>
Ingo Molnar5f921ae2006-03-26 01:37:17 -080038#include <linux/mutex.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>
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -070041
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#include <asm/uaccess.h>
43
44#include "util.h"
45
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080046struct shm_file_data {
47 int id;
48 struct ipc_namespace *ns;
49 struct file *file;
50 const struct vm_operations_struct *vm_ops;
51};
52
53#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
54
Arjan van de Ven9a321442007-02-12 00:55:35 -080055static const struct file_operations shm_file_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056static struct vm_operations_struct shm_vm_ops;
57
Kirill Korotaev4e982312006-10-02 02:18:22 -070058static struct ipc_ids init_shm_ids;
Linus Torvalds1da177e2005-04-16 15:20:36 -070059
Kirill Korotaev4e982312006-10-02 02:18:22 -070060#define shm_ids(ns) (*((ns)->ids[IPC_SHM_IDS]))
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
Kirill Korotaev4e982312006-10-02 02:18:22 -070062#define shm_lock(ns, id) \
63 ((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id))
64#define shm_unlock(shp) \
65 ipc_unlock(&(shp)->shm_perm)
66#define shm_get(ns, id) \
67 ((struct shmid_kernel*)ipc_get(&shm_ids(ns),id))
68#define shm_buildid(ns, id, seq) \
69 ipc_buildid(&shm_ids(ns), id, seq)
70
71static int newseg (struct ipc_namespace *ns, key_t key,
72 int shmflg, size_t size);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080073static void shm_open(struct vm_area_struct *vma);
74static void shm_close(struct vm_area_struct *vma);
Kirill Korotaev4e982312006-10-02 02:18:22 -070075static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -070077static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
Linus Torvalds1da177e2005-04-16 15:20:36 -070078#endif
79
Kirill Korotaev4e982312006-10-02 02:18:22 -070080static void __ipc_init __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
81{
82 ns->ids[IPC_SHM_IDS] = ids;
83 ns->shm_ctlmax = SHMMAX;
84 ns->shm_ctlall = SHMALL;
85 ns->shm_ctlmni = SHMMNI;
86 ns->shm_tot = 0;
87 ipc_init_ids(ids, 1);
88}
Linus Torvalds1da177e2005-04-16 15:20:36 -070089
Kirill Korotaev4e982312006-10-02 02:18:22 -070090static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
91{
92 if (shp->shm_nattch){
93 shp->shm_perm.mode |= SHM_DEST;
94 /* Do not find it any more */
95 shp->shm_perm.key = IPC_PRIVATE;
96 shm_unlock(shp);
97 } else
98 shm_destroy(ns, shp);
99}
100
101#ifdef CONFIG_IPC_NS
102int shm_init_ns(struct ipc_namespace *ns)
103{
104 struct ipc_ids *ids;
105
106 ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
107 if (ids == NULL)
108 return -ENOMEM;
109
110 __shm_init_ns(ns, ids);
111 return 0;
112}
113
114void shm_exit_ns(struct ipc_namespace *ns)
115{
116 int i;
117 struct shmid_kernel *shp;
118
119 mutex_lock(&shm_ids(ns).mutex);
120 for (i = 0; i <= shm_ids(ns).max_id; i++) {
121 shp = shm_lock(ns, i);
122 if (shp == NULL)
123 continue;
124
125 do_shm_rmid(ns, shp);
126 }
127 mutex_unlock(&shm_ids(ns).mutex);
128
Pavel Emelianovc7e12b82006-11-02 22:07:03 -0800129 ipc_fini_ids(ns->ids[IPC_SHM_IDS]);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700130 kfree(ns->ids[IPC_SHM_IDS]);
131 ns->ids[IPC_SHM_IDS] = NULL;
132}
133#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134
135void __init shm_init (void)
136{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700137 __shm_init_ns(&init_ipc_ns, &init_shm_ids);
Mike Waychison19b49462005-09-06 15:17:10 -0700138 ipc_init_proc_interface("sysvipc/shm",
139 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
Kirill Korotaev4e982312006-10-02 02:18:22 -0700140 IPC_SHM_IDS, sysvipc_shm_proc_show);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141}
142
Kirill Korotaev4e982312006-10-02 02:18:22 -0700143static inline int shm_checkid(struct ipc_namespace *ns,
144 struct shmid_kernel *s, int id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700146 if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 return -EIDRM;
148 return 0;
149}
150
Kirill Korotaev4e982312006-10-02 02:18:22 -0700151static inline struct shmid_kernel *shm_rmid(struct ipc_namespace *ns, int id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700153 return (struct shmid_kernel *)ipc_rmid(&shm_ids(ns), id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154}
155
Kirill Korotaev4e982312006-10-02 02:18:22 -0700156static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700158 return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159}
160
161
162
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800163/* This is called by fork, once for every shm attach. */
164static void shm_open(struct vm_area_struct *vma)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700165{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800166 struct file *file = vma->vm_file;
167 struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 struct shmid_kernel *shp;
169
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800170 shp = shm_lock(sfd->ns, sfd->id);
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200171 BUG_ON(!shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 shp->shm_atim = get_seconds();
173 shp->shm_lprid = current->tgid;
174 shp->shm_nattch++;
175 shm_unlock(shp);
176}
177
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178/*
179 * shm_destroy - free the struct shmid_kernel
180 *
181 * @shp: struct to free
182 *
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800183 * It has to be called with shp and shm_ids.mutex locked,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 * but returns with shp unlocked and freed.
185 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700186static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700188 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
189 shm_rmid(ns, shp->id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 shm_unlock(shp);
191 if (!is_file_hugepages(shp->shm_file))
192 shmem_lock(shp->shm_file, 0, shp->mlock_user);
193 else
Josef Sipek6d630792006-12-08 02:37:11 -0800194 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 shp->mlock_user);
196 fput (shp->shm_file);
197 security_shm_free(shp);
198 ipc_rcu_putref(shp);
199}
200
201/*
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800202 * remove the attach descriptor vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 * free memory for segment if it is marked destroyed.
204 * The descriptor has already been removed from the current->mm->mmap list
205 * and will later be kfree()d.
206 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800207static void shm_close(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800209 struct file * file = vma->vm_file;
210 struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 struct shmid_kernel *shp;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800212 struct ipc_namespace *ns = sfd->ns;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700213
214 mutex_lock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 /* remove from the list of attaches of the shm segment */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800216 shp = shm_lock(ns, sfd->id);
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200217 BUG_ON(!shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 shp->shm_lprid = current->tgid;
219 shp->shm_dtim = get_seconds();
220 shp->shm_nattch--;
221 if(shp->shm_nattch == 0 &&
Andrew Mortonb33291c2006-01-08 01:02:21 -0800222 shp->shm_perm.mode & SHM_DEST)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700223 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 else
225 shm_unlock(shp);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700226 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227}
228
Adrian Bunkde01bad2007-02-28 20:11:01 -0800229static struct page *shm_nopage(struct vm_area_struct *vma,
230 unsigned long address, int *type)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800231{
232 struct file *file = vma->vm_file;
233 struct shm_file_data *sfd = shm_file_data(file);
234
235 return sfd->vm_ops->nopage(vma, address, type);
236}
237
238#ifdef CONFIG_NUMA
239int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
240{
241 struct file *file = vma->vm_file;
242 struct shm_file_data *sfd = shm_file_data(file);
243 int err = 0;
244 if (sfd->vm_ops->set_policy)
245 err = sfd->vm_ops->set_policy(vma, new);
246 return err;
247}
248
249struct mempolicy *shm_get_policy(struct vm_area_struct *vma, unsigned long addr)
250{
251 struct file *file = vma->vm_file;
252 struct shm_file_data *sfd = shm_file_data(file);
253 struct mempolicy *pol = NULL;
254
255 if (sfd->vm_ops->get_policy)
256 pol = sfd->vm_ops->get_policy(vma, addr);
Adam Litke22741922007-06-16 10:16:15 -0700257 else if (vma->vm_policy)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800258 pol = vma->vm_policy;
Adam Litke22741922007-06-16 10:16:15 -0700259 else
260 pol = current->mempolicy;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800261 return pol;
262}
263#endif
264
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265static int shm_mmap(struct file * file, struct vm_area_struct * vma)
266{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800267 struct shm_file_data *sfd = shm_file_data(file);
David Howellsb0e15192006-01-06 00:11:42 -0800268 int ret;
269
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800270 ret = sfd->file->f_op->mmap(sfd->file, vma);
271 if (ret != 0)
272 return ret;
273 sfd->vm_ops = vma->vm_ops;
274 vma->vm_ops = &shm_vm_ops;
275 shm_open(vma);
David Howellsb0e15192006-01-06 00:11:42 -0800276
277 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278}
279
Kirill Korotaev4e982312006-10-02 02:18:22 -0700280static int shm_release(struct inode *ino, struct file *file)
281{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800282 struct shm_file_data *sfd = shm_file_data(file);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700283
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800284 put_ipc_ns(sfd->ns);
285 shm_file_data(file) = NULL;
286 kfree(sfd);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700287 return 0;
288}
289
Adam Litke516dffd2007-03-01 15:46:08 -0800290static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
291{
292 int (*fsync) (struct file *, struct dentry *, int datasync);
293 struct shm_file_data *sfd = shm_file_data(file);
294 int ret = -EINVAL;
295
296 fsync = sfd->file->f_op->fsync;
297 if (fsync)
298 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
299 return ret;
300}
301
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800302static unsigned long shm_get_unmapped_area(struct file *file,
303 unsigned long addr, unsigned long len, unsigned long pgoff,
304 unsigned long flags)
305{
306 struct shm_file_data *sfd = shm_file_data(file);
Adam Litke516dffd2007-03-01 15:46:08 -0800307 return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800308}
Adam Litke516dffd2007-03-01 15:46:08 -0800309
310int is_file_shm_hugepages(struct file *file)
311{
312 int ret = 0;
313
314 if (file->f_op == &shm_file_operations) {
315 struct shm_file_data *sfd;
316 sfd = shm_file_data(file);
317 ret = is_file_hugepages(sfd->file);
318 }
319 return ret;
320}
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800321
Arjan van de Ven9a321442007-02-12 00:55:35 -0800322static const struct file_operations shm_file_operations = {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700323 .mmap = shm_mmap,
Adam Litke516dffd2007-03-01 15:46:08 -0800324 .fsync = shm_fsync,
Kirill Korotaev4e982312006-10-02 02:18:22 -0700325 .release = shm_release,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800326 .get_unmapped_area = shm_get_unmapped_area,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327};
328
329static struct vm_operations_struct shm_vm_ops = {
330 .open = shm_open, /* callback for a new vm-area open */
331 .close = shm_close, /* callback for when the vm-area is released */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800332 .nopage = shm_nopage,
333#if defined(CONFIG_NUMA)
334 .set_policy = shm_set_policy,
335 .get_policy = shm_get_policy,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336#endif
337};
338
Kirill Korotaev4e982312006-10-02 02:18:22 -0700339static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340{
341 int error;
342 struct shmid_kernel *shp;
343 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
344 struct file * file;
345 char name[13];
346 int id;
347
Kirill Korotaev4e982312006-10-02 02:18:22 -0700348 if (size < SHMMIN || size > ns->shm_ctlmax)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 return -EINVAL;
350
Guy Streeterf66d45e2007-01-23 12:20:04 -0600351 if (ns->shm_tot + numpages > ns->shm_ctlall)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 return -ENOSPC;
353
354 shp = ipc_rcu_alloc(sizeof(*shp));
355 if (!shp)
356 return -ENOMEM;
357
358 shp->shm_perm.key = key;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800359 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 shp->mlock_user = NULL;
361
362 shp->shm_perm.security = NULL;
363 error = security_shm_alloc(shp);
364 if (error) {
365 ipc_rcu_putref(shp);
366 return error;
367 }
368
Eric W. Biederman9d665862007-06-16 10:16:16 -0700369 sprintf (name, "SYSV%08x", key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 if (shmflg & SHM_HUGETLB) {
Eric W. Biederman9d665862007-06-16 10:16:16 -0700371 /* hugetlb_file_setup takes care of mlock user accounting */
372 file = hugetlb_file_setup(name, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 shp->mlock_user = current->user;
374 } else {
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800375 int acctflag = VM_ACCOUNT;
376 /*
377 * Do not allow no accounting for OVERCOMMIT_NEVER, even
378 * if it's asked for.
379 */
380 if ((shmflg & SHM_NORESERVE) &&
381 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
382 acctflag = 0;
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800383 file = shmem_file_setup(name, size, acctflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 }
385 error = PTR_ERR(file);
386 if (IS_ERR(file))
387 goto no_file;
388
389 error = -ENOSPC;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700390 id = shm_addid(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391 if(id == -1)
392 goto no_id;
393
394 shp->shm_cprid = current->tgid;
395 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;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700400 shp->id = shm_buildid(ns, id, shp->shm_perm.seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 shp->shm_file = file;
Badari Pulavarty30475cc2007-06-16 10:15:59 -0700402 /*
403 * shmid gets reported as "inode#" in /proc/pid/maps.
404 * proc-ps tools use this. Changing this will break them.
405 */
406 file->f_dentry->d_inode->i_ino = shp->id;
Krishnakumar R551110a2005-10-29 18:16:45 -0700407
Kirill Korotaev4e982312006-10-02 02:18:22 -0700408 ns->shm_tot += numpages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 shm_unlock(shp);
410 return shp->id;
411
412no_id:
413 fput(file);
414no_file:
415 security_shm_free(shp);
416 ipc_rcu_putref(shp);
417 return error;
418}
419
420asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
421{
422 struct shmid_kernel *shp;
423 int err, id = 0;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700424 struct ipc_namespace *ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425
Kirill Korotaev4e982312006-10-02 02:18:22 -0700426 ns = current->nsproxy->ipc_ns;
427
428 mutex_lock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429 if (key == IPC_PRIVATE) {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700430 err = newseg(ns, key, shmflg, size);
431 } else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 if (!(shmflg & IPC_CREAT))
433 err = -ENOENT;
434 else
Kirill Korotaev4e982312006-10-02 02:18:22 -0700435 err = newseg(ns, key, shmflg, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
437 err = -EEXIST;
438 } else {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700439 shp = shm_lock(ns, id);
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200440 BUG_ON(shp==NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 if (shp->shm_segsz < size)
442 err = -EINVAL;
443 else if (ipcperms(&shp->shm_perm, shmflg))
444 err = -EACCES;
445 else {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700446 int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 err = security_shm_associate(shp, shmflg);
448 if (!err)
449 err = shmid;
450 }
451 shm_unlock(shp);
452 }
Kirill Korotaev4e982312006-10-02 02:18:22 -0700453 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454
455 return err;
456}
457
458static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
459{
460 switch(version) {
461 case IPC_64:
462 return copy_to_user(buf, in, sizeof(*in));
463 case IPC_OLD:
464 {
465 struct shmid_ds out;
466
467 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
468 out.shm_segsz = in->shm_segsz;
469 out.shm_atime = in->shm_atime;
470 out.shm_dtime = in->shm_dtime;
471 out.shm_ctime = in->shm_ctime;
472 out.shm_cpid = in->shm_cpid;
473 out.shm_lpid = in->shm_lpid;
474 out.shm_nattch = in->shm_nattch;
475
476 return copy_to_user(buf, &out, sizeof(out));
477 }
478 default:
479 return -EINVAL;
480 }
481}
482
483struct shm_setbuf {
484 uid_t uid;
485 gid_t gid;
486 mode_t mode;
487};
488
489static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
490{
491 switch(version) {
492 case IPC_64:
493 {
494 struct shmid64_ds tbuf;
495
496 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
497 return -EFAULT;
498
499 out->uid = tbuf.shm_perm.uid;
500 out->gid = tbuf.shm_perm.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800501 out->mode = tbuf.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502
503 return 0;
504 }
505 case IPC_OLD:
506 {
507 struct shmid_ds tbuf_old;
508
509 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
510 return -EFAULT;
511
512 out->uid = tbuf_old.shm_perm.uid;
513 out->gid = tbuf_old.shm_perm.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800514 out->mode = tbuf_old.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515
516 return 0;
517 }
518 default:
519 return -EINVAL;
520 }
521}
522
523static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
524{
525 switch(version) {
526 case IPC_64:
527 return copy_to_user(buf, in, sizeof(*in));
528 case IPC_OLD:
529 {
530 struct shminfo out;
531
532 if(in->shmmax > INT_MAX)
533 out.shmmax = INT_MAX;
534 else
535 out.shmmax = (int)in->shmmax;
536
537 out.shmmin = in->shmmin;
538 out.shmmni = in->shmmni;
539 out.shmseg = in->shmseg;
540 out.shmall = in->shmall;
541
542 return copy_to_user(buf, &out, sizeof(out));
543 }
544 default:
545 return -EINVAL;
546 }
547}
548
Kirill Korotaev4e982312006-10-02 02:18:22 -0700549static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
550 unsigned long *swp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551{
552 int i;
553
554 *rss = 0;
555 *swp = 0;
556
Kirill Korotaev4e982312006-10-02 02:18:22 -0700557 for (i = 0; i <= shm_ids(ns).max_id; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 struct shmid_kernel *shp;
559 struct inode *inode;
560
Kirill Korotaev4e982312006-10-02 02:18:22 -0700561 shp = shm_get(ns, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 if(!shp)
563 continue;
564
Josef Sipek6d630792006-12-08 02:37:11 -0800565 inode = shp->shm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566
567 if (is_file_hugepages(shp->shm_file)) {
568 struct address_space *mapping = inode->i_mapping;
569 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
570 } else {
571 struct shmem_inode_info *info = SHMEM_I(inode);
572 spin_lock(&info->lock);
573 *rss += inode->i_mapping->nrpages;
574 *swp += info->swapped;
575 spin_unlock(&info->lock);
576 }
577 }
578}
579
580asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
581{
582 struct shm_setbuf setbuf;
583 struct shmid_kernel *shp;
584 int err, version;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700585 struct ipc_namespace *ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586
587 if (cmd < 0 || shmid < 0) {
588 err = -EINVAL;
589 goto out;
590 }
591
592 version = ipc_parse_version(&cmd);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700593 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594
595 switch (cmd) { /* replace with proc interface ? */
596 case IPC_INFO:
597 {
598 struct shminfo64 shminfo;
599
600 err = security_shm_shmctl(NULL, cmd);
601 if (err)
602 return err;
603
604 memset(&shminfo,0,sizeof(shminfo));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700605 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
606 shminfo.shmmax = ns->shm_ctlmax;
607 shminfo.shmall = ns->shm_ctlall;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608
609 shminfo.shmmin = SHMMIN;
610 if(copy_shminfo_to_user (buf, &shminfo, version))
611 return -EFAULT;
612 /* reading a integer is always atomic */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700613 err= shm_ids(ns).max_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 if(err<0)
615 err = 0;
616 goto out;
617 }
618 case SHM_INFO:
619 {
620 struct shm_info shm_info;
621
622 err = security_shm_shmctl(NULL, cmd);
623 if (err)
624 return err;
625
626 memset(&shm_info,0,sizeof(shm_info));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700627 mutex_lock(&shm_ids(ns).mutex);
628 shm_info.used_ids = shm_ids(ns).in_use;
629 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
630 shm_info.shm_tot = ns->shm_tot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 shm_info.swap_attempts = 0;
632 shm_info.swap_successes = 0;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700633 err = shm_ids(ns).max_id;
634 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
636 err = -EFAULT;
637 goto out;
638 }
639
640 err = err < 0 ? 0 : err;
641 goto out;
642 }
643 case SHM_STAT:
644 case IPC_STAT:
645 {
646 struct shmid64_ds tbuf;
647 int result;
648 memset(&tbuf, 0, sizeof(tbuf));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700649 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 if(shp==NULL) {
651 err = -EINVAL;
652 goto out;
653 } else if(cmd==SHM_STAT) {
654 err = -EINVAL;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700655 if (shmid > shm_ids(ns).max_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 goto out_unlock;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700657 result = shm_buildid(ns, shmid, shp->shm_perm.seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 } else {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700659 err = shm_checkid(ns, shp,shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 if(err)
661 goto out_unlock;
662 result = 0;
663 }
664 err=-EACCES;
665 if (ipcperms (&shp->shm_perm, S_IRUGO))
666 goto out_unlock;
667 err = security_shm_shmctl(shp, cmd);
668 if (err)
669 goto out_unlock;
670 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
671 tbuf.shm_segsz = shp->shm_segsz;
672 tbuf.shm_atime = shp->shm_atim;
673 tbuf.shm_dtime = shp->shm_dtim;
674 tbuf.shm_ctime = shp->shm_ctim;
675 tbuf.shm_cpid = shp->shm_cprid;
676 tbuf.shm_lpid = shp->shm_lprid;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800677 tbuf.shm_nattch = shp->shm_nattch;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 shm_unlock(shp);
679 if(copy_shmid_to_user (buf, &tbuf, version))
680 err = -EFAULT;
681 else
682 err = result;
683 goto out;
684 }
685 case SHM_LOCK:
686 case SHM_UNLOCK:
687 {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700688 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689 if(shp==NULL) {
690 err = -EINVAL;
691 goto out;
692 }
Kirill Korotaev4e982312006-10-02 02:18:22 -0700693 err = shm_checkid(ns, shp,shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 if(err)
695 goto out_unlock;
696
Steve Grubb073115d2006-04-02 17:07:33 -0400697 err = audit_ipc_obj(&(shp->shm_perm));
698 if (err)
699 goto out_unlock;
700
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 if (!capable(CAP_IPC_LOCK)) {
702 err = -EPERM;
703 if (current->euid != shp->shm_perm.uid &&
704 current->euid != shp->shm_perm.cuid)
705 goto out_unlock;
706 if (cmd == SHM_LOCK &&
707 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
708 goto out_unlock;
709 }
710
711 err = security_shm_shmctl(shp, cmd);
712 if (err)
713 goto out_unlock;
714
715 if(cmd==SHM_LOCK) {
716 struct user_struct * user = current->user;
717 if (!is_file_hugepages(shp->shm_file)) {
718 err = shmem_lock(shp->shm_file, 1, user);
719 if (!err) {
Andrew Mortonb33291c2006-01-08 01:02:21 -0800720 shp->shm_perm.mode |= SHM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721 shp->mlock_user = user;
722 }
723 }
724 } else if (!is_file_hugepages(shp->shm_file)) {
725 shmem_lock(shp->shm_file, 0, shp->mlock_user);
Andrew Mortonb33291c2006-01-08 01:02:21 -0800726 shp->shm_perm.mode &= ~SHM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 shp->mlock_user = NULL;
728 }
729 shm_unlock(shp);
730 goto out;
731 }
732 case IPC_RMID:
733 {
734 /*
735 * We cannot simply remove the file. The SVID states
736 * that the block remains until the last person
737 * detaches from it, then is deleted. A shmat() on
738 * an RMID segment is legal in older Linux and if
739 * we change it apps break...
740 *
741 * Instead we set a destroyed flag, and then blow
742 * the name away when the usage hits zero.
743 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700744 mutex_lock(&shm_ids(ns).mutex);
745 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 err = -EINVAL;
747 if (shp == NULL)
748 goto out_up;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700749 err = shm_checkid(ns, shp, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 if(err)
751 goto out_unlock_up;
752
Steve Grubb073115d2006-04-02 17:07:33 -0400753 err = audit_ipc_obj(&(shp->shm_perm));
754 if (err)
755 goto out_unlock_up;
756
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 if (current->euid != shp->shm_perm.uid &&
758 current->euid != shp->shm_perm.cuid &&
759 !capable(CAP_SYS_ADMIN)) {
760 err=-EPERM;
761 goto out_unlock_up;
762 }
763
764 err = security_shm_shmctl(shp, cmd);
765 if (err)
766 goto out_unlock_up;
767
Kirill Korotaev4e982312006-10-02 02:18:22 -0700768 do_shm_rmid(ns, shp);
769 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 goto out;
771 }
772
773 case IPC_SET:
774 {
775 if (copy_shmid_from_user (&setbuf, buf, version)) {
776 err = -EFAULT;
777 goto out;
778 }
Kirill Korotaev4e982312006-10-02 02:18:22 -0700779 mutex_lock(&shm_ids(ns).mutex);
780 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 err=-EINVAL;
782 if(shp==NULL)
783 goto out_up;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700784 err = shm_checkid(ns, shp,shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785 if(err)
786 goto out_unlock_up;
Steve Grubb073115d2006-04-02 17:07:33 -0400787 err = audit_ipc_obj(&(shp->shm_perm));
788 if (err)
789 goto out_unlock_up;
Linda Knippersac032212006-05-16 22:03:48 -0400790 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
Steve Grubb073115d2006-04-02 17:07:33 -0400791 if (err)
792 goto out_unlock_up;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 err=-EPERM;
794 if (current->euid != shp->shm_perm.uid &&
795 current->euid != shp->shm_perm.cuid &&
796 !capable(CAP_SYS_ADMIN)) {
797 goto out_unlock_up;
798 }
799
800 err = security_shm_shmctl(shp, cmd);
801 if (err)
802 goto out_unlock_up;
803
804 shp->shm_perm.uid = setbuf.uid;
805 shp->shm_perm.gid = setbuf.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800806 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 | (setbuf.mode & S_IRWXUGO);
808 shp->shm_ctim = get_seconds();
809 break;
810 }
811
812 default:
813 err = -EINVAL;
814 goto out;
815 }
816
817 err = 0;
818out_unlock_up:
819 shm_unlock(shp);
820out_up:
Kirill Korotaev4e982312006-10-02 02:18:22 -0700821 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 goto out;
823out_unlock:
824 shm_unlock(shp);
825out:
826 return err;
827}
828
829/*
830 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
831 *
832 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
833 * "raddr" thing points to kernel space, and there has to be a wrapper around
834 * this.
835 */
836long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
837{
838 struct shmid_kernel *shp;
839 unsigned long addr;
840 unsigned long size;
841 struct file * file;
842 int err;
843 unsigned long flags;
844 unsigned long prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845 int acc_mode;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800846 unsigned long user_addr;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700847 struct ipc_namespace *ns;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800848 struct shm_file_data *sfd;
849 struct path path;
850 mode_t f_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800852 err = -EINVAL;
853 if (shmid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 goto out;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800855 else if ((addr = (ulong)shmaddr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 if (addr & (SHMLBA-1)) {
857 if (shmflg & SHM_RND)
858 addr &= ~(SHMLBA-1); /* round down */
859 else
860#ifndef __ARCH_FORCE_SHMLBA
861 if (addr & ~PAGE_MASK)
862#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800863 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 }
865 flags = MAP_SHARED | MAP_FIXED;
866 } else {
867 if ((shmflg & SHM_REMAP))
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800868 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869
870 flags = MAP_SHARED;
871 }
872
873 if (shmflg & SHM_RDONLY) {
874 prot = PROT_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 acc_mode = S_IRUGO;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800876 f_mode = FMODE_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 } else {
878 prot = PROT_READ | PROT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 acc_mode = S_IRUGO | S_IWUGO;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800880 f_mode = FMODE_READ | FMODE_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 }
882 if (shmflg & SHM_EXEC) {
883 prot |= PROT_EXEC;
884 acc_mode |= S_IXUGO;
885 }
886
887 /*
888 * We cannot rely on the fs check since SYSV IPC does have an
889 * additional creator id...
890 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700891 ns = current->nsproxy->ipc_ns;
892 shp = shm_lock(ns, shmid);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800893 if(shp == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894 goto out;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800895
Kirill Korotaev4e982312006-10-02 02:18:22 -0700896 err = shm_checkid(ns, shp,shmid);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800897 if (err)
898 goto out_unlock;
899
900 err = -EACCES;
901 if (ipcperms(&shp->shm_perm, acc_mode))
902 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903
904 err = security_shm_shmat(shp, shmaddr, shmflg);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800905 if (err)
906 goto out_unlock;
907
908 path.dentry = dget(shp->shm_file->f_path.dentry);
909 path.mnt = mntget(shp->shm_file->f_path.mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 shp->shm_nattch++;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800911 size = i_size_read(path.dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912 shm_unlock(shp);
913
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800914 err = -ENOMEM;
915 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
916 if (!sfd)
917 goto out_put_path;
918
919 err = -ENOMEM;
920 file = get_empty_filp();
921 if (!file)
922 goto out_free;
923
924 file->f_op = &shm_file_operations;
925 file->private_data = sfd;
926 file->f_path = path;
927 file->f_mapping = shp->shm_file->f_mapping;
928 file->f_mode = f_mode;
929 sfd->id = shp->id;
930 sfd->ns = get_ipc_ns(ns);
931 sfd->file = shp->shm_file;
932 sfd->vm_ops = NULL;
933
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934 down_write(&current->mm->mmap_sem);
935 if (addr && !(shmflg & SHM_REMAP)) {
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800936 err = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 if (find_vma_intersection(current->mm, addr, addr + size))
938 goto invalid;
939 /*
940 * If shm segment goes below stack, make sure there is some
941 * space left for the stack to grow (at least 4 pages).
942 */
943 if (addr < current->mm->start_stack &&
944 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
945 goto invalid;
946 }
947
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800948 user_addr = do_mmap (file, addr, size, prot, flags, 0);
949 *raddr = user_addr;
950 err = 0;
951 if (IS_ERR_VALUE(user_addr))
952 err = (long)user_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953invalid:
954 up_write(&current->mm->mmap_sem);
955
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800956 fput(file);
957
958out_nattch:
Kirill Korotaev4e982312006-10-02 02:18:22 -0700959 mutex_lock(&shm_ids(ns).mutex);
960 shp = shm_lock(ns, shmid);
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200961 BUG_ON(!shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 shp->shm_nattch--;
963 if(shp->shm_nattch == 0 &&
Andrew Mortonb33291c2006-01-08 01:02:21 -0800964 shp->shm_perm.mode & SHM_DEST)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700965 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966 else
967 shm_unlock(shp);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700968 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970out:
971 return err;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800972
973out_unlock:
974 shm_unlock(shp);
975 goto out;
976
977out_free:
978 kfree(sfd);
979out_put_path:
980 dput(path.dentry);
981 mntput(path.mnt);
982 goto out_nattch;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983}
984
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -0700985asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
986{
987 unsigned long ret;
988 long err;
989
990 err = do_shmat(shmid, shmaddr, shmflg, &ret);
991 if (err)
992 return err;
993 force_successful_syscall_return();
994 return (long)ret;
995}
996
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997/*
998 * detach and kill segment if marked destroyed.
999 * The work is done in shm_close.
1000 */
1001asmlinkage long sys_shmdt(char __user *shmaddr)
1002{
1003 struct mm_struct *mm = current->mm;
1004 struct vm_area_struct *vma, *next;
1005 unsigned long addr = (unsigned long)shmaddr;
1006 loff_t size = 0;
1007 int retval = -EINVAL;
1008
Hugh Dickinsdf1e2fb2006-03-24 03:18:06 -08001009 if (addr & ~PAGE_MASK)
1010 return retval;
1011
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012 down_write(&mm->mmap_sem);
1013
1014 /*
1015 * This function tries to be smart and unmap shm segments that
1016 * were modified by partial mlock or munmap calls:
1017 * - It first determines the size of the shm segment that should be
1018 * unmapped: It searches for a vma that is backed by shm and that
1019 * started at address shmaddr. It records it's size and then unmaps
1020 * it.
1021 * - Then it unmaps all shm vmas that started at shmaddr and that
1022 * are within the initially determined size.
1023 * Errors from do_munmap are ignored: the function only fails if
1024 * it's called with invalid parameters or if it's called to unmap
1025 * a part of a vma. Both calls in this function are for full vmas,
1026 * the parameters are directly copied from the vma itself and always
1027 * valid - therefore do_munmap cannot fail. (famous last words?)
1028 */
1029 /*
1030 * If it had been mremap()'d, the starting address would not
1031 * match the usual checks anyway. So assume all vma's are
1032 * above the starting address given.
1033 */
1034 vma = find_vma(mm, addr);
1035
1036 while (vma) {
1037 next = vma->vm_next;
1038
1039 /*
1040 * Check if the starting address would match, i.e. it's
1041 * a fragment created by mprotect() and/or munmap(), or it
1042 * otherwise it starts at this address with no hassles.
1043 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001044 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1046
1047
Josef Sipek6d630792006-12-08 02:37:11 -08001048 size = vma->vm_file->f_path.dentry->d_inode->i_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001049 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1050 /*
1051 * We discovered the size of the shm segment, so
1052 * break out of here and fall through to the next
1053 * loop that uses the size information to stop
1054 * searching for matching vma's.
1055 */
1056 retval = 0;
1057 vma = next;
1058 break;
1059 }
1060 vma = next;
1061 }
1062
1063 /*
1064 * We need look no further than the maximum address a fragment
1065 * could possibly have landed at. Also cast things to loff_t to
1066 * prevent overflows and make comparisions vs. equal-width types.
1067 */
KAMEZAWA Hiroyuki8e367092006-02-10 01:51:12 -08001068 size = PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1070 next = vma->vm_next;
1071
1072 /* finding a matching vma now does not alter retval */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001073 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1075
1076 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1077 vma = next;
1078 }
1079
1080 up_write(&mm->mmap_sem);
1081 return retval;
1082}
1083
1084#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -07001085static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086{
Mike Waychison19b49462005-09-06 15:17:10 -07001087 struct shmid_kernel *shp = it;
1088 char *format;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1091#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 -07001092
Mike Waychison19b49462005-09-06 15:17:10 -07001093 if (sizeof(size_t) <= sizeof(int))
1094 format = SMALL_STRING;
1095 else
1096 format = BIG_STRING;
1097 return seq_printf(s, format,
1098 shp->shm_perm.key,
1099 shp->id,
Andrew Mortonb33291c2006-01-08 01:02:21 -08001100 shp->shm_perm.mode,
Mike Waychison19b49462005-09-06 15:17:10 -07001101 shp->shm_segsz,
1102 shp->shm_cprid,
1103 shp->shm_lprid,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001104 shp->shm_nattch,
Mike Waychison19b49462005-09-06 15:17:10 -07001105 shp->shm_perm.uid,
1106 shp->shm_perm.gid,
1107 shp->shm_perm.cuid,
1108 shp->shm_perm.cgid,
1109 shp->shm_atim,
1110 shp->shm_dtim,
1111 shp->shm_ctim);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112}
1113#endif