blob: 3d0eb7940e9c1b524c1d3f5295c73e0aa666f661 [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);
257 else
258 pol = vma->vm_policy;
259 return pol;
260}
261#endif
262
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263static int shm_mmap(struct file * file, struct vm_area_struct * vma)
264{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800265 struct shm_file_data *sfd = shm_file_data(file);
David Howellsb0e15192006-01-06 00:11:42 -0800266 int ret;
267
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800268 ret = sfd->file->f_op->mmap(sfd->file, vma);
269 if (ret != 0)
270 return ret;
271 sfd->vm_ops = vma->vm_ops;
272 vma->vm_ops = &shm_vm_ops;
273 shm_open(vma);
David Howellsb0e15192006-01-06 00:11:42 -0800274
275 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276}
277
Kirill Korotaev4e982312006-10-02 02:18:22 -0700278static int shm_release(struct inode *ino, struct file *file)
279{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800280 struct shm_file_data *sfd = shm_file_data(file);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700281
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800282 put_ipc_ns(sfd->ns);
283 shm_file_data(file) = NULL;
284 kfree(sfd);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700285 return 0;
286}
287
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800288#ifndef CONFIG_MMU
289static unsigned long shm_get_unmapped_area(struct file *file,
290 unsigned long addr, unsigned long len, unsigned long pgoff,
291 unsigned long flags)
292{
293 struct shm_file_data *sfd = shm_file_data(file);
294 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len, pgoff,
295 flags);
296}
297#else
298#define shm_get_unmapped_area NULL
299#endif
300
Arjan van de Ven9a321442007-02-12 00:55:35 -0800301static const struct file_operations shm_file_operations = {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700302 .mmap = shm_mmap,
303 .release = shm_release,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800304 .get_unmapped_area = shm_get_unmapped_area,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305};
306
307static struct vm_operations_struct shm_vm_ops = {
308 .open = shm_open, /* callback for a new vm-area open */
309 .close = shm_close, /* callback for when the vm-area is released */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800310 .nopage = shm_nopage,
311#if defined(CONFIG_NUMA)
312 .set_policy = shm_set_policy,
313 .get_policy = shm_get_policy,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314#endif
315};
316
Kirill Korotaev4e982312006-10-02 02:18:22 -0700317static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318{
319 int error;
320 struct shmid_kernel *shp;
321 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
322 struct file * file;
323 char name[13];
324 int id;
325
Kirill Korotaev4e982312006-10-02 02:18:22 -0700326 if (size < SHMMIN || size > ns->shm_ctlmax)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 return -EINVAL;
328
Guy Streeterf66d45e2007-01-23 12:20:04 -0600329 if (ns->shm_tot + numpages > ns->shm_ctlall)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 return -ENOSPC;
331
332 shp = ipc_rcu_alloc(sizeof(*shp));
333 if (!shp)
334 return -ENOMEM;
335
336 shp->shm_perm.key = key;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800337 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 shp->mlock_user = NULL;
339
340 shp->shm_perm.security = NULL;
341 error = security_shm_alloc(shp);
342 if (error) {
343 ipc_rcu_putref(shp);
344 return error;
345 }
346
347 if (shmflg & SHM_HUGETLB) {
348 /* hugetlb_zero_setup takes care of mlock user accounting */
349 file = hugetlb_zero_setup(size);
350 shp->mlock_user = current->user;
351 } else {
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800352 int acctflag = VM_ACCOUNT;
353 /*
354 * Do not allow no accounting for OVERCOMMIT_NEVER, even
355 * if it's asked for.
356 */
357 if ((shmflg & SHM_NORESERVE) &&
358 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
359 acctflag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 sprintf (name, "SYSV%08x", key);
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800361 file = shmem_file_setup(name, size, acctflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 }
363 error = PTR_ERR(file);
364 if (IS_ERR(file))
365 goto no_file;
366
367 error = -ENOSPC;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700368 id = shm_addid(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 if(id == -1)
370 goto no_id;
371
372 shp->shm_cprid = current->tgid;
373 shp->shm_lprid = 0;
374 shp->shm_atim = shp->shm_dtim = 0;
375 shp->shm_ctim = get_seconds();
376 shp->shm_segsz = size;
377 shp->shm_nattch = 0;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700378 shp->id = shm_buildid(ns, id, shp->shm_perm.seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 shp->shm_file = file;
Krishnakumar R551110a2005-10-29 18:16:45 -0700380
Kirill Korotaev4e982312006-10-02 02:18:22 -0700381 ns->shm_tot += numpages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 shm_unlock(shp);
383 return shp->id;
384
385no_id:
386 fput(file);
387no_file:
388 security_shm_free(shp);
389 ipc_rcu_putref(shp);
390 return error;
391}
392
393asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
394{
395 struct shmid_kernel *shp;
396 int err, id = 0;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700397 struct ipc_namespace *ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398
Kirill Korotaev4e982312006-10-02 02:18:22 -0700399 ns = current->nsproxy->ipc_ns;
400
401 mutex_lock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 if (key == IPC_PRIVATE) {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700403 err = newseg(ns, key, shmflg, size);
404 } else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 if (!(shmflg & IPC_CREAT))
406 err = -ENOENT;
407 else
Kirill Korotaev4e982312006-10-02 02:18:22 -0700408 err = newseg(ns, key, shmflg, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
410 err = -EEXIST;
411 } else {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700412 shp = shm_lock(ns, id);
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200413 BUG_ON(shp==NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 if (shp->shm_segsz < size)
415 err = -EINVAL;
416 else if (ipcperms(&shp->shm_perm, shmflg))
417 err = -EACCES;
418 else {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700419 int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 err = security_shm_associate(shp, shmflg);
421 if (!err)
422 err = shmid;
423 }
424 shm_unlock(shp);
425 }
Kirill Korotaev4e982312006-10-02 02:18:22 -0700426 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427
428 return err;
429}
430
431static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
432{
433 switch(version) {
434 case IPC_64:
435 return copy_to_user(buf, in, sizeof(*in));
436 case IPC_OLD:
437 {
438 struct shmid_ds out;
439
440 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
441 out.shm_segsz = in->shm_segsz;
442 out.shm_atime = in->shm_atime;
443 out.shm_dtime = in->shm_dtime;
444 out.shm_ctime = in->shm_ctime;
445 out.shm_cpid = in->shm_cpid;
446 out.shm_lpid = in->shm_lpid;
447 out.shm_nattch = in->shm_nattch;
448
449 return copy_to_user(buf, &out, sizeof(out));
450 }
451 default:
452 return -EINVAL;
453 }
454}
455
456struct shm_setbuf {
457 uid_t uid;
458 gid_t gid;
459 mode_t mode;
460};
461
462static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
463{
464 switch(version) {
465 case IPC_64:
466 {
467 struct shmid64_ds tbuf;
468
469 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
470 return -EFAULT;
471
472 out->uid = tbuf.shm_perm.uid;
473 out->gid = tbuf.shm_perm.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800474 out->mode = tbuf.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475
476 return 0;
477 }
478 case IPC_OLD:
479 {
480 struct shmid_ds tbuf_old;
481
482 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
483 return -EFAULT;
484
485 out->uid = tbuf_old.shm_perm.uid;
486 out->gid = tbuf_old.shm_perm.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800487 out->mode = tbuf_old.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488
489 return 0;
490 }
491 default:
492 return -EINVAL;
493 }
494}
495
496static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
497{
498 switch(version) {
499 case IPC_64:
500 return copy_to_user(buf, in, sizeof(*in));
501 case IPC_OLD:
502 {
503 struct shminfo out;
504
505 if(in->shmmax > INT_MAX)
506 out.shmmax = INT_MAX;
507 else
508 out.shmmax = (int)in->shmmax;
509
510 out.shmmin = in->shmmin;
511 out.shmmni = in->shmmni;
512 out.shmseg = in->shmseg;
513 out.shmall = in->shmall;
514
515 return copy_to_user(buf, &out, sizeof(out));
516 }
517 default:
518 return -EINVAL;
519 }
520}
521
Kirill Korotaev4e982312006-10-02 02:18:22 -0700522static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
523 unsigned long *swp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524{
525 int i;
526
527 *rss = 0;
528 *swp = 0;
529
Kirill Korotaev4e982312006-10-02 02:18:22 -0700530 for (i = 0; i <= shm_ids(ns).max_id; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 struct shmid_kernel *shp;
532 struct inode *inode;
533
Kirill Korotaev4e982312006-10-02 02:18:22 -0700534 shp = shm_get(ns, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 if(!shp)
536 continue;
537
Josef Sipek6d630792006-12-08 02:37:11 -0800538 inode = shp->shm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539
540 if (is_file_hugepages(shp->shm_file)) {
541 struct address_space *mapping = inode->i_mapping;
542 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
543 } else {
544 struct shmem_inode_info *info = SHMEM_I(inode);
545 spin_lock(&info->lock);
546 *rss += inode->i_mapping->nrpages;
547 *swp += info->swapped;
548 spin_unlock(&info->lock);
549 }
550 }
551}
552
553asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
554{
555 struct shm_setbuf setbuf;
556 struct shmid_kernel *shp;
557 int err, version;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700558 struct ipc_namespace *ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559
560 if (cmd < 0 || shmid < 0) {
561 err = -EINVAL;
562 goto out;
563 }
564
565 version = ipc_parse_version(&cmd);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700566 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567
568 switch (cmd) { /* replace with proc interface ? */
569 case IPC_INFO:
570 {
571 struct shminfo64 shminfo;
572
573 err = security_shm_shmctl(NULL, cmd);
574 if (err)
575 return err;
576
577 memset(&shminfo,0,sizeof(shminfo));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700578 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
579 shminfo.shmmax = ns->shm_ctlmax;
580 shminfo.shmall = ns->shm_ctlall;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581
582 shminfo.shmmin = SHMMIN;
583 if(copy_shminfo_to_user (buf, &shminfo, version))
584 return -EFAULT;
585 /* reading a integer is always atomic */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700586 err= shm_ids(ns).max_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 if(err<0)
588 err = 0;
589 goto out;
590 }
591 case SHM_INFO:
592 {
593 struct shm_info shm_info;
594
595 err = security_shm_shmctl(NULL, cmd);
596 if (err)
597 return err;
598
599 memset(&shm_info,0,sizeof(shm_info));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700600 mutex_lock(&shm_ids(ns).mutex);
601 shm_info.used_ids = shm_ids(ns).in_use;
602 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
603 shm_info.shm_tot = ns->shm_tot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604 shm_info.swap_attempts = 0;
605 shm_info.swap_successes = 0;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700606 err = shm_ids(ns).max_id;
607 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
609 err = -EFAULT;
610 goto out;
611 }
612
613 err = err < 0 ? 0 : err;
614 goto out;
615 }
616 case SHM_STAT:
617 case IPC_STAT:
618 {
619 struct shmid64_ds tbuf;
620 int result;
621 memset(&tbuf, 0, sizeof(tbuf));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700622 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 if(shp==NULL) {
624 err = -EINVAL;
625 goto out;
626 } else if(cmd==SHM_STAT) {
627 err = -EINVAL;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700628 if (shmid > shm_ids(ns).max_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 goto out_unlock;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700630 result = shm_buildid(ns, shmid, shp->shm_perm.seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 } else {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700632 err = shm_checkid(ns, shp,shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 if(err)
634 goto out_unlock;
635 result = 0;
636 }
637 err=-EACCES;
638 if (ipcperms (&shp->shm_perm, S_IRUGO))
639 goto out_unlock;
640 err = security_shm_shmctl(shp, cmd);
641 if (err)
642 goto out_unlock;
643 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
644 tbuf.shm_segsz = shp->shm_segsz;
645 tbuf.shm_atime = shp->shm_atim;
646 tbuf.shm_dtime = shp->shm_dtim;
647 tbuf.shm_ctime = shp->shm_ctim;
648 tbuf.shm_cpid = shp->shm_cprid;
649 tbuf.shm_lpid = shp->shm_lprid;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800650 tbuf.shm_nattch = shp->shm_nattch;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 shm_unlock(shp);
652 if(copy_shmid_to_user (buf, &tbuf, version))
653 err = -EFAULT;
654 else
655 err = result;
656 goto out;
657 }
658 case SHM_LOCK:
659 case SHM_UNLOCK:
660 {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700661 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 if(shp==NULL) {
663 err = -EINVAL;
664 goto out;
665 }
Kirill Korotaev4e982312006-10-02 02:18:22 -0700666 err = shm_checkid(ns, shp,shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 if(err)
668 goto out_unlock;
669
Steve Grubb073115d2006-04-02 17:07:33 -0400670 err = audit_ipc_obj(&(shp->shm_perm));
671 if (err)
672 goto out_unlock;
673
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 if (!capable(CAP_IPC_LOCK)) {
675 err = -EPERM;
676 if (current->euid != shp->shm_perm.uid &&
677 current->euid != shp->shm_perm.cuid)
678 goto out_unlock;
679 if (cmd == SHM_LOCK &&
680 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
681 goto out_unlock;
682 }
683
684 err = security_shm_shmctl(shp, cmd);
685 if (err)
686 goto out_unlock;
687
688 if(cmd==SHM_LOCK) {
689 struct user_struct * user = current->user;
690 if (!is_file_hugepages(shp->shm_file)) {
691 err = shmem_lock(shp->shm_file, 1, user);
692 if (!err) {
Andrew Mortonb33291c2006-01-08 01:02:21 -0800693 shp->shm_perm.mode |= SHM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 shp->mlock_user = user;
695 }
696 }
697 } else if (!is_file_hugepages(shp->shm_file)) {
698 shmem_lock(shp->shm_file, 0, shp->mlock_user);
Andrew Mortonb33291c2006-01-08 01:02:21 -0800699 shp->shm_perm.mode &= ~SHM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 shp->mlock_user = NULL;
701 }
702 shm_unlock(shp);
703 goto out;
704 }
705 case IPC_RMID:
706 {
707 /*
708 * We cannot simply remove the file. The SVID states
709 * that the block remains until the last person
710 * detaches from it, then is deleted. A shmat() on
711 * an RMID segment is legal in older Linux and if
712 * we change it apps break...
713 *
714 * Instead we set a destroyed flag, and then blow
715 * the name away when the usage hits zero.
716 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700717 mutex_lock(&shm_ids(ns).mutex);
718 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 err = -EINVAL;
720 if (shp == NULL)
721 goto out_up;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700722 err = shm_checkid(ns, shp, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 if(err)
724 goto out_unlock_up;
725
Steve Grubb073115d2006-04-02 17:07:33 -0400726 err = audit_ipc_obj(&(shp->shm_perm));
727 if (err)
728 goto out_unlock_up;
729
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 if (current->euid != shp->shm_perm.uid &&
731 current->euid != shp->shm_perm.cuid &&
732 !capable(CAP_SYS_ADMIN)) {
733 err=-EPERM;
734 goto out_unlock_up;
735 }
736
737 err = security_shm_shmctl(shp, cmd);
738 if (err)
739 goto out_unlock_up;
740
Kirill Korotaev4e982312006-10-02 02:18:22 -0700741 do_shm_rmid(ns, shp);
742 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 goto out;
744 }
745
746 case IPC_SET:
747 {
748 if (copy_shmid_from_user (&setbuf, buf, version)) {
749 err = -EFAULT;
750 goto out;
751 }
Kirill Korotaev4e982312006-10-02 02:18:22 -0700752 mutex_lock(&shm_ids(ns).mutex);
753 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 err=-EINVAL;
755 if(shp==NULL)
756 goto out_up;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700757 err = shm_checkid(ns, shp,shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 if(err)
759 goto out_unlock_up;
Steve Grubb073115d2006-04-02 17:07:33 -0400760 err = audit_ipc_obj(&(shp->shm_perm));
761 if (err)
762 goto out_unlock_up;
Linda Knippersac032212006-05-16 22:03:48 -0400763 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
Steve Grubb073115d2006-04-02 17:07:33 -0400764 if (err)
765 goto out_unlock_up;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 err=-EPERM;
767 if (current->euid != shp->shm_perm.uid &&
768 current->euid != shp->shm_perm.cuid &&
769 !capable(CAP_SYS_ADMIN)) {
770 goto out_unlock_up;
771 }
772
773 err = security_shm_shmctl(shp, cmd);
774 if (err)
775 goto out_unlock_up;
776
777 shp->shm_perm.uid = setbuf.uid;
778 shp->shm_perm.gid = setbuf.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800779 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 | (setbuf.mode & S_IRWXUGO);
781 shp->shm_ctim = get_seconds();
782 break;
783 }
784
785 default:
786 err = -EINVAL;
787 goto out;
788 }
789
790 err = 0;
791out_unlock_up:
792 shm_unlock(shp);
793out_up:
Kirill Korotaev4e982312006-10-02 02:18:22 -0700794 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 goto out;
796out_unlock:
797 shm_unlock(shp);
798out:
799 return err;
800}
801
802/*
803 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
804 *
805 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
806 * "raddr" thing points to kernel space, and there has to be a wrapper around
807 * this.
808 */
809long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
810{
811 struct shmid_kernel *shp;
812 unsigned long addr;
813 unsigned long size;
814 struct file * file;
815 int err;
816 unsigned long flags;
817 unsigned long prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 int acc_mode;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800819 unsigned long user_addr;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700820 struct ipc_namespace *ns;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800821 struct shm_file_data *sfd;
822 struct path path;
823 mode_t f_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800825 err = -EINVAL;
826 if (shmid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 goto out;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800828 else if ((addr = (ulong)shmaddr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 if (addr & (SHMLBA-1)) {
830 if (shmflg & SHM_RND)
831 addr &= ~(SHMLBA-1); /* round down */
832 else
833#ifndef __ARCH_FORCE_SHMLBA
834 if (addr & ~PAGE_MASK)
835#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800836 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 }
838 flags = MAP_SHARED | MAP_FIXED;
839 } else {
840 if ((shmflg & SHM_REMAP))
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800841 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842
843 flags = MAP_SHARED;
844 }
845
846 if (shmflg & SHM_RDONLY) {
847 prot = PROT_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 acc_mode = S_IRUGO;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800849 f_mode = FMODE_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850 } else {
851 prot = PROT_READ | PROT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 acc_mode = S_IRUGO | S_IWUGO;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800853 f_mode = FMODE_READ | FMODE_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 }
855 if (shmflg & SHM_EXEC) {
856 prot |= PROT_EXEC;
857 acc_mode |= S_IXUGO;
858 }
859
860 /*
861 * We cannot rely on the fs check since SYSV IPC does have an
862 * additional creator id...
863 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700864 ns = current->nsproxy->ipc_ns;
865 shp = shm_lock(ns, shmid);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800866 if(shp == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 goto out;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800868
Kirill Korotaev4e982312006-10-02 02:18:22 -0700869 err = shm_checkid(ns, shp,shmid);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800870 if (err)
871 goto out_unlock;
872
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
881 path.dentry = dget(shp->shm_file->f_path.dentry);
882 path.mnt = mntget(shp->shm_file->f_path.mnt);
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)
890 goto out_put_path;
891
892 err = -ENOMEM;
893 file = get_empty_filp();
894 if (!file)
895 goto out_free;
896
897 file->f_op = &shm_file_operations;
898 file->private_data = sfd;
899 file->f_path = path;
900 file->f_mapping = shp->shm_file->f_mapping;
901 file->f_mode = f_mode;
902 sfd->id = shp->id;
903 sfd->ns = get_ipc_ns(ns);
904 sfd->file = shp->shm_file;
905 sfd->vm_ops = NULL;
906
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 down_write(&current->mm->mmap_sem);
908 if (addr && !(shmflg & SHM_REMAP)) {
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800909 err = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 if (find_vma_intersection(current->mm, addr, addr + size))
911 goto invalid;
912 /*
913 * If shm segment goes below stack, make sure there is some
914 * space left for the stack to grow (at least 4 pages).
915 */
916 if (addr < current->mm->start_stack &&
917 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
918 goto invalid;
919 }
920
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800921 user_addr = do_mmap (file, addr, size, prot, flags, 0);
922 *raddr = user_addr;
923 err = 0;
924 if (IS_ERR_VALUE(user_addr))
925 err = (long)user_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926invalid:
927 up_write(&current->mm->mmap_sem);
928
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800929 fput(file);
930
931out_nattch:
Kirill Korotaev4e982312006-10-02 02:18:22 -0700932 mutex_lock(&shm_ids(ns).mutex);
933 shp = shm_lock(ns, shmid);
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200934 BUG_ON(!shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 shp->shm_nattch--;
936 if(shp->shm_nattch == 0 &&
Andrew Mortonb33291c2006-01-08 01:02:21 -0800937 shp->shm_perm.mode & SHM_DEST)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700938 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939 else
940 shm_unlock(shp);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700941 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943out:
944 return err;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800945
946out_unlock:
947 shm_unlock(shp);
948 goto out;
949
950out_free:
951 kfree(sfd);
952out_put_path:
953 dput(path.dentry);
954 mntput(path.mnt);
955 goto out_nattch;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956}
957
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -0700958asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
959{
960 unsigned long ret;
961 long err;
962
963 err = do_shmat(shmid, shmaddr, shmflg, &ret);
964 if (err)
965 return err;
966 force_successful_syscall_return();
967 return (long)ret;
968}
969
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970/*
971 * detach and kill segment if marked destroyed.
972 * The work is done in shm_close.
973 */
974asmlinkage long sys_shmdt(char __user *shmaddr)
975{
976 struct mm_struct *mm = current->mm;
977 struct vm_area_struct *vma, *next;
978 unsigned long addr = (unsigned long)shmaddr;
979 loff_t size = 0;
980 int retval = -EINVAL;
981
Hugh Dickinsdf1e2fb2006-03-24 03:18:06 -0800982 if (addr & ~PAGE_MASK)
983 return retval;
984
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985 down_write(&mm->mmap_sem);
986
987 /*
988 * This function tries to be smart and unmap shm segments that
989 * were modified by partial mlock or munmap calls:
990 * - It first determines the size of the shm segment that should be
991 * unmapped: It searches for a vma that is backed by shm and that
992 * started at address shmaddr. It records it's size and then unmaps
993 * it.
994 * - Then it unmaps all shm vmas that started at shmaddr and that
995 * are within the initially determined size.
996 * Errors from do_munmap are ignored: the function only fails if
997 * it's called with invalid parameters or if it's called to unmap
998 * a part of a vma. Both calls in this function are for full vmas,
999 * the parameters are directly copied from the vma itself and always
1000 * valid - therefore do_munmap cannot fail. (famous last words?)
1001 */
1002 /*
1003 * If it had been mremap()'d, the starting address would not
1004 * match the usual checks anyway. So assume all vma's are
1005 * above the starting address given.
1006 */
1007 vma = find_vma(mm, addr);
1008
1009 while (vma) {
1010 next = vma->vm_next;
1011
1012 /*
1013 * Check if the starting address would match, i.e. it's
1014 * a fragment created by mprotect() and/or munmap(), or it
1015 * otherwise it starts at this address with no hassles.
1016 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001017 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1019
1020
Josef Sipek6d630792006-12-08 02:37:11 -08001021 size = vma->vm_file->f_path.dentry->d_inode->i_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1023 /*
1024 * We discovered the size of the shm segment, so
1025 * break out of here and fall through to the next
1026 * loop that uses the size information to stop
1027 * searching for matching vma's.
1028 */
1029 retval = 0;
1030 vma = next;
1031 break;
1032 }
1033 vma = next;
1034 }
1035
1036 /*
1037 * We need look no further than the maximum address a fragment
1038 * could possibly have landed at. Also cast things to loff_t to
1039 * prevent overflows and make comparisions vs. equal-width types.
1040 */
KAMEZAWA Hiroyuki8e367092006-02-10 01:51:12 -08001041 size = PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1043 next = vma->vm_next;
1044
1045 /* finding a matching vma now does not alter retval */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001046 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1048
1049 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1050 vma = next;
1051 }
1052
1053 up_write(&mm->mmap_sem);
1054 return retval;
1055}
1056
1057#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -07001058static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059{
Mike Waychison19b49462005-09-06 15:17:10 -07001060 struct shmid_kernel *shp = it;
1061 char *format;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001062
Linus Torvalds1da177e2005-04-16 15:20:36 -07001063#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1064#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 -07001065
Mike Waychison19b49462005-09-06 15:17:10 -07001066 if (sizeof(size_t) <= sizeof(int))
1067 format = SMALL_STRING;
1068 else
1069 format = BIG_STRING;
1070 return seq_printf(s, format,
1071 shp->shm_perm.key,
1072 shp->id,
Andrew Mortonb33291c2006-01-08 01:02:21 -08001073 shp->shm_perm.mode,
Mike Waychison19b49462005-09-06 15:17:10 -07001074 shp->shm_segsz,
1075 shp->shm_cprid,
1076 shp->shm_lprid,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001077 shp->shm_nattch,
Mike Waychison19b49462005-09-06 15:17:10 -07001078 shp->shm_perm.uid,
1079 shp->shm_perm.gid,
1080 shp->shm_perm.cuid,
1081 shp->shm_perm.cgid,
1082 shp->shm_atim,
1083 shp->shm_dtim,
1084 shp->shm_ctim);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085}
1086#endif