blob: 242c3f66493a1c1cdf578a1b5fd9eb7777ade965 [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
Cedric Le Goater7d69a1f2007-07-15 23:40:58 -070080static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
Kirill Korotaev4e982312006-10-02 02:18:22 -070081{
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
Kirill Korotaev4e982312006-10-02 02:18:22 -0700101int shm_init_ns(struct ipc_namespace *ns)
102{
103 struct ipc_ids *ids;
104
105 ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
106 if (ids == NULL)
107 return -ENOMEM;
108
109 __shm_init_ns(ns, ids);
110 return 0;
111}
112
113void shm_exit_ns(struct ipc_namespace *ns)
114{
115 int i;
116 struct shmid_kernel *shp;
117
118 mutex_lock(&shm_ids(ns).mutex);
119 for (i = 0; i <= shm_ids(ns).max_id; i++) {
120 shp = shm_lock(ns, i);
121 if (shp == NULL)
122 continue;
123
124 do_shm_rmid(ns, shp);
125 }
126 mutex_unlock(&shm_ids(ns).mutex);
127
Pavel Emelianovc7e12b82006-11-02 22:07:03 -0800128 ipc_fini_ids(ns->ids[IPC_SHM_IDS]);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700129 kfree(ns->ids[IPC_SHM_IDS]);
130 ns->ids[IPC_SHM_IDS] = NULL;
131}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
133void __init shm_init (void)
134{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700135 __shm_init_ns(&init_ipc_ns, &init_shm_ids);
Mike Waychison19b49462005-09-06 15:17:10 -0700136 ipc_init_proc_interface("sysvipc/shm",
137 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
Kirill Korotaev4e982312006-10-02 02:18:22 -0700138 IPC_SHM_IDS, sysvipc_shm_proc_show);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139}
140
Kirill Korotaev4e982312006-10-02 02:18:22 -0700141static inline int shm_checkid(struct ipc_namespace *ns,
142 struct shmid_kernel *s, int id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700144 if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 return -EIDRM;
146 return 0;
147}
148
Kirill Korotaev4e982312006-10-02 02:18:22 -0700149static inline struct shmid_kernel *shm_rmid(struct ipc_namespace *ns, int id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700151 return (struct shmid_kernel *)ipc_rmid(&shm_ids(ns), id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152}
153
Kirill Korotaev4e982312006-10-02 02:18:22 -0700154static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700156 return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157}
158
159
160
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800161/* This is called by fork, once for every shm attach. */
162static void shm_open(struct vm_area_struct *vma)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700163{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800164 struct file *file = vma->vm_file;
165 struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 struct shmid_kernel *shp;
167
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800168 shp = shm_lock(sfd->ns, sfd->id);
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200169 BUG_ON(!shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 shp->shm_atim = get_seconds();
171 shp->shm_lprid = current->tgid;
172 shp->shm_nattch++;
173 shm_unlock(shp);
174}
175
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176/*
177 * shm_destroy - free the struct shmid_kernel
178 *
179 * @shp: struct to free
180 *
Ingo Molnar5f921ae2006-03-26 01:37:17 -0800181 * It has to be called with shp and shm_ids.mutex locked,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 * but returns with shp unlocked and freed.
183 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700184static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700186 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
187 shm_rmid(ns, shp->id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 shm_unlock(shp);
189 if (!is_file_hugepages(shp->shm_file))
190 shmem_lock(shp->shm_file, 0, shp->mlock_user);
191 else
Josef Sipek6d630792006-12-08 02:37:11 -0800192 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 shp->mlock_user);
194 fput (shp->shm_file);
195 security_shm_free(shp);
196 ipc_rcu_putref(shp);
197}
198
199/*
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800200 * remove the attach descriptor vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 * free memory for segment if it is marked destroyed.
202 * The descriptor has already been removed from the current->mm->mmap list
203 * and will later be kfree()d.
204 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800205static void shm_close(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800207 struct file * file = vma->vm_file;
208 struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 struct shmid_kernel *shp;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800210 struct ipc_namespace *ns = sfd->ns;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700211
212 mutex_lock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 /* remove from the list of attaches of the shm segment */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800214 shp = shm_lock(ns, sfd->id);
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200215 BUG_ON(!shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 shp->shm_lprid = current->tgid;
217 shp->shm_dtim = get_seconds();
218 shp->shm_nattch--;
219 if(shp->shm_nattch == 0 &&
Andrew Mortonb33291c2006-01-08 01:02:21 -0800220 shp->shm_perm.mode & SHM_DEST)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700221 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 else
223 shm_unlock(shp);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700224 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225}
226
Adrian Bunkde01bad2007-02-28 20:11:01 -0800227static struct page *shm_nopage(struct vm_area_struct *vma,
228 unsigned long address, int *type)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800229{
230 struct file *file = vma->vm_file;
231 struct shm_file_data *sfd = shm_file_data(file);
232
233 return sfd->vm_ops->nopage(vma, address, type);
234}
235
236#ifdef CONFIG_NUMA
237int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
238{
239 struct file *file = vma->vm_file;
240 struct shm_file_data *sfd = shm_file_data(file);
241 int err = 0;
242 if (sfd->vm_ops->set_policy)
243 err = sfd->vm_ops->set_policy(vma, new);
244 return err;
245}
246
247struct mempolicy *shm_get_policy(struct vm_area_struct *vma, unsigned long addr)
248{
249 struct file *file = vma->vm_file;
250 struct shm_file_data *sfd = shm_file_data(file);
251 struct mempolicy *pol = NULL;
252
253 if (sfd->vm_ops->get_policy)
254 pol = sfd->vm_ops->get_policy(vma, addr);
Adam Litke22741922007-06-16 10:16:15 -0700255 else if (vma->vm_policy)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800256 pol = vma->vm_policy;
Adam Litke22741922007-06-16 10:16:15 -0700257 else
258 pol = current->mempolicy;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800259 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
Adam Litke516dffd2007-03-01 15:46:08 -0800288static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
289{
290 int (*fsync) (struct file *, struct dentry *, int datasync);
291 struct shm_file_data *sfd = shm_file_data(file);
292 int ret = -EINVAL;
293
294 fsync = sfd->file->f_op->fsync;
295 if (fsync)
296 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
297 return ret;
298}
299
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800300static unsigned long shm_get_unmapped_area(struct file *file,
301 unsigned long addr, unsigned long len, unsigned long pgoff,
302 unsigned long flags)
303{
304 struct shm_file_data *sfd = shm_file_data(file);
Adam Litke516dffd2007-03-01 15:46:08 -0800305 return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800306}
Adam Litke516dffd2007-03-01 15:46:08 -0800307
308int is_file_shm_hugepages(struct file *file)
309{
310 int ret = 0;
311
312 if (file->f_op == &shm_file_operations) {
313 struct shm_file_data *sfd;
314 sfd = shm_file_data(file);
315 ret = is_file_hugepages(sfd->file);
316 }
317 return ret;
318}
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800319
Arjan van de Ven9a321442007-02-12 00:55:35 -0800320static const struct file_operations shm_file_operations = {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700321 .mmap = shm_mmap,
Adam Litke516dffd2007-03-01 15:46:08 -0800322 .fsync = shm_fsync,
Kirill Korotaev4e982312006-10-02 02:18:22 -0700323 .release = shm_release,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800324 .get_unmapped_area = shm_get_unmapped_area,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325};
326
327static struct vm_operations_struct shm_vm_ops = {
328 .open = shm_open, /* callback for a new vm-area open */
329 .close = shm_close, /* callback for when the vm-area is released */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800330 .nopage = shm_nopage,
331#if defined(CONFIG_NUMA)
332 .set_policy = shm_set_policy,
333 .get_policy = shm_get_policy,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334#endif
335};
336
Kirill Korotaev4e982312006-10-02 02:18:22 -0700337static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338{
339 int error;
340 struct shmid_kernel *shp;
341 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
342 struct file * file;
343 char name[13];
344 int id;
345
Kirill Korotaev4e982312006-10-02 02:18:22 -0700346 if (size < SHMMIN || size > ns->shm_ctlmax)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 return -EINVAL;
348
Guy Streeterf66d45e2007-01-23 12:20:04 -0600349 if (ns->shm_tot + numpages > ns->shm_ctlall)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 return -ENOSPC;
351
352 shp = ipc_rcu_alloc(sizeof(*shp));
353 if (!shp)
354 return -ENOMEM;
355
356 shp->shm_perm.key = key;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800357 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 shp->mlock_user = NULL;
359
360 shp->shm_perm.security = NULL;
361 error = security_shm_alloc(shp);
362 if (error) {
363 ipc_rcu_putref(shp);
364 return error;
365 }
366
Eric W. Biederman9d665862007-06-16 10:16:16 -0700367 sprintf (name, "SYSV%08x", key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 if (shmflg & SHM_HUGETLB) {
Eric W. Biederman9d665862007-06-16 10:16:16 -0700369 /* hugetlb_file_setup takes care of mlock user accounting */
370 file = hugetlb_file_setup(name, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 shp->mlock_user = current->user;
372 } else {
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800373 int acctflag = VM_ACCOUNT;
374 /*
375 * Do not allow no accounting for OVERCOMMIT_NEVER, even
376 * if it's asked for.
377 */
378 if ((shmflg & SHM_NORESERVE) &&
379 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
380 acctflag = 0;
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800381 file = shmem_file_setup(name, size, acctflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 }
383 error = PTR_ERR(file);
384 if (IS_ERR(file))
385 goto no_file;
386
387 error = -ENOSPC;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700388 id = shm_addid(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 if(id == -1)
390 goto no_id;
391
392 shp->shm_cprid = current->tgid;
393 shp->shm_lprid = 0;
394 shp->shm_atim = shp->shm_dtim = 0;
395 shp->shm_ctim = get_seconds();
396 shp->shm_segsz = size;
397 shp->shm_nattch = 0;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700398 shp->id = shm_buildid(ns, id, shp->shm_perm.seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 shp->shm_file = file;
Badari Pulavarty30475cc2007-06-16 10:15:59 -0700400 /*
401 * shmid gets reported as "inode#" in /proc/pid/maps.
402 * proc-ps tools use this. Changing this will break them.
403 */
404 file->f_dentry->d_inode->i_ino = shp->id;
Krishnakumar R551110a2005-10-29 18:16:45 -0700405
Kirill Korotaev4e982312006-10-02 02:18:22 -0700406 ns->shm_tot += numpages;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407 shm_unlock(shp);
408 return shp->id;
409
410no_id:
411 fput(file);
412no_file:
413 security_shm_free(shp);
414 ipc_rcu_putref(shp);
415 return error;
416}
417
418asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
419{
420 struct shmid_kernel *shp;
421 int err, id = 0;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700422 struct ipc_namespace *ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423
Kirill Korotaev4e982312006-10-02 02:18:22 -0700424 ns = current->nsproxy->ipc_ns;
425
426 mutex_lock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 if (key == IPC_PRIVATE) {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700428 err = newseg(ns, key, shmflg, size);
429 } else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 if (!(shmflg & IPC_CREAT))
431 err = -ENOENT;
432 else
Kirill Korotaev4e982312006-10-02 02:18:22 -0700433 err = newseg(ns, key, shmflg, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
435 err = -EEXIST;
436 } else {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700437 shp = shm_lock(ns, id);
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200438 BUG_ON(shp==NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 if (shp->shm_segsz < size)
440 err = -EINVAL;
441 else if (ipcperms(&shp->shm_perm, shmflg))
442 err = -EACCES;
443 else {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700444 int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 err = security_shm_associate(shp, shmflg);
446 if (!err)
447 err = shmid;
448 }
449 shm_unlock(shp);
450 }
Kirill Korotaev4e982312006-10-02 02:18:22 -0700451 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452
453 return err;
454}
455
456static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
457{
458 switch(version) {
459 case IPC_64:
460 return copy_to_user(buf, in, sizeof(*in));
461 case IPC_OLD:
462 {
463 struct shmid_ds out;
464
465 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
466 out.shm_segsz = in->shm_segsz;
467 out.shm_atime = in->shm_atime;
468 out.shm_dtime = in->shm_dtime;
469 out.shm_ctime = in->shm_ctime;
470 out.shm_cpid = in->shm_cpid;
471 out.shm_lpid = in->shm_lpid;
472 out.shm_nattch = in->shm_nattch;
473
474 return copy_to_user(buf, &out, sizeof(out));
475 }
476 default:
477 return -EINVAL;
478 }
479}
480
481struct shm_setbuf {
482 uid_t uid;
483 gid_t gid;
484 mode_t mode;
485};
486
487static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
488{
489 switch(version) {
490 case IPC_64:
491 {
492 struct shmid64_ds tbuf;
493
494 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
495 return -EFAULT;
496
497 out->uid = tbuf.shm_perm.uid;
498 out->gid = tbuf.shm_perm.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800499 out->mode = tbuf.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500
501 return 0;
502 }
503 case IPC_OLD:
504 {
505 struct shmid_ds tbuf_old;
506
507 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
508 return -EFAULT;
509
510 out->uid = tbuf_old.shm_perm.uid;
511 out->gid = tbuf_old.shm_perm.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800512 out->mode = tbuf_old.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513
514 return 0;
515 }
516 default:
517 return -EINVAL;
518 }
519}
520
521static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
522{
523 switch(version) {
524 case IPC_64:
525 return copy_to_user(buf, in, sizeof(*in));
526 case IPC_OLD:
527 {
528 struct shminfo out;
529
530 if(in->shmmax > INT_MAX)
531 out.shmmax = INT_MAX;
532 else
533 out.shmmax = (int)in->shmmax;
534
535 out.shmmin = in->shmmin;
536 out.shmmni = in->shmmni;
537 out.shmseg = in->shmseg;
538 out.shmall = in->shmall;
539
540 return copy_to_user(buf, &out, sizeof(out));
541 }
542 default:
543 return -EINVAL;
544 }
545}
546
Kirill Korotaev4e982312006-10-02 02:18:22 -0700547static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
548 unsigned long *swp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549{
550 int i;
551
552 *rss = 0;
553 *swp = 0;
554
Kirill Korotaev4e982312006-10-02 02:18:22 -0700555 for (i = 0; i <= shm_ids(ns).max_id; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 struct shmid_kernel *shp;
557 struct inode *inode;
558
Kirill Korotaev4e982312006-10-02 02:18:22 -0700559 shp = shm_get(ns, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 if(!shp)
561 continue;
562
Josef Sipek6d630792006-12-08 02:37:11 -0800563 inode = shp->shm_file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564
565 if (is_file_hugepages(shp->shm_file)) {
566 struct address_space *mapping = inode->i_mapping;
567 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
568 } else {
569 struct shmem_inode_info *info = SHMEM_I(inode);
570 spin_lock(&info->lock);
571 *rss += inode->i_mapping->nrpages;
572 *swp += info->swapped;
573 spin_unlock(&info->lock);
574 }
575 }
576}
577
578asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
579{
580 struct shm_setbuf setbuf;
581 struct shmid_kernel *shp;
582 int err, version;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700583 struct ipc_namespace *ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584
585 if (cmd < 0 || shmid < 0) {
586 err = -EINVAL;
587 goto out;
588 }
589
590 version = ipc_parse_version(&cmd);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700591 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592
593 switch (cmd) { /* replace with proc interface ? */
594 case IPC_INFO:
595 {
596 struct shminfo64 shminfo;
597
598 err = security_shm_shmctl(NULL, cmd);
599 if (err)
600 return err;
601
602 memset(&shminfo,0,sizeof(shminfo));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700603 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
604 shminfo.shmmax = ns->shm_ctlmax;
605 shminfo.shmall = ns->shm_ctlall;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606
607 shminfo.shmmin = SHMMIN;
608 if(copy_shminfo_to_user (buf, &shminfo, version))
609 return -EFAULT;
610 /* reading a integer is always atomic */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700611 err= shm_ids(ns).max_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 if(err<0)
613 err = 0;
614 goto out;
615 }
616 case SHM_INFO:
617 {
618 struct shm_info shm_info;
619
620 err = security_shm_shmctl(NULL, cmd);
621 if (err)
622 return err;
623
624 memset(&shm_info,0,sizeof(shm_info));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700625 mutex_lock(&shm_ids(ns).mutex);
626 shm_info.used_ids = shm_ids(ns).in_use;
627 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
628 shm_info.shm_tot = ns->shm_tot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 shm_info.swap_attempts = 0;
630 shm_info.swap_successes = 0;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700631 err = shm_ids(ns).max_id;
632 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
634 err = -EFAULT;
635 goto out;
636 }
637
638 err = err < 0 ? 0 : err;
639 goto out;
640 }
641 case SHM_STAT:
642 case IPC_STAT:
643 {
644 struct shmid64_ds tbuf;
645 int result;
646 memset(&tbuf, 0, sizeof(tbuf));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700647 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 if(shp==NULL) {
649 err = -EINVAL;
650 goto out;
651 } else if(cmd==SHM_STAT) {
652 err = -EINVAL;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700653 if (shmid > shm_ids(ns).max_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 goto out_unlock;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700655 result = shm_buildid(ns, shmid, shp->shm_perm.seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 } else {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700657 err = shm_checkid(ns, shp,shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 if(err)
659 goto out_unlock;
660 result = 0;
661 }
662 err=-EACCES;
663 if (ipcperms (&shp->shm_perm, S_IRUGO))
664 goto out_unlock;
665 err = security_shm_shmctl(shp, cmd);
666 if (err)
667 goto out_unlock;
668 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
669 tbuf.shm_segsz = shp->shm_segsz;
670 tbuf.shm_atime = shp->shm_atim;
671 tbuf.shm_dtime = shp->shm_dtim;
672 tbuf.shm_ctime = shp->shm_ctim;
673 tbuf.shm_cpid = shp->shm_cprid;
674 tbuf.shm_lpid = shp->shm_lprid;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800675 tbuf.shm_nattch = shp->shm_nattch;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 shm_unlock(shp);
677 if(copy_shmid_to_user (buf, &tbuf, version))
678 err = -EFAULT;
679 else
680 err = result;
681 goto out;
682 }
683 case SHM_LOCK:
684 case SHM_UNLOCK:
685 {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700686 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 if(shp==NULL) {
688 err = -EINVAL;
689 goto out;
690 }
Kirill Korotaev4e982312006-10-02 02:18:22 -0700691 err = shm_checkid(ns, shp,shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 if(err)
693 goto out_unlock;
694
Steve Grubb073115d2006-04-02 17:07:33 -0400695 err = audit_ipc_obj(&(shp->shm_perm));
696 if (err)
697 goto out_unlock;
698
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 if (!capable(CAP_IPC_LOCK)) {
700 err = -EPERM;
701 if (current->euid != shp->shm_perm.uid &&
702 current->euid != shp->shm_perm.cuid)
703 goto out_unlock;
704 if (cmd == SHM_LOCK &&
705 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
706 goto out_unlock;
707 }
708
709 err = security_shm_shmctl(shp, cmd);
710 if (err)
711 goto out_unlock;
712
713 if(cmd==SHM_LOCK) {
714 struct user_struct * user = current->user;
715 if (!is_file_hugepages(shp->shm_file)) {
716 err = shmem_lock(shp->shm_file, 1, user);
717 if (!err) {
Andrew Mortonb33291c2006-01-08 01:02:21 -0800718 shp->shm_perm.mode |= SHM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 shp->mlock_user = user;
720 }
721 }
722 } else if (!is_file_hugepages(shp->shm_file)) {
723 shmem_lock(shp->shm_file, 0, shp->mlock_user);
Andrew Mortonb33291c2006-01-08 01:02:21 -0800724 shp->shm_perm.mode &= ~SHM_LOCKED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 shp->mlock_user = NULL;
726 }
727 shm_unlock(shp);
728 goto out;
729 }
730 case IPC_RMID:
731 {
732 /*
733 * We cannot simply remove the file. The SVID states
734 * that the block remains until the last person
735 * detaches from it, then is deleted. A shmat() on
736 * an RMID segment is legal in older Linux and if
737 * we change it apps break...
738 *
739 * Instead we set a destroyed flag, and then blow
740 * the name away when the usage hits zero.
741 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700742 mutex_lock(&shm_ids(ns).mutex);
743 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 err = -EINVAL;
745 if (shp == NULL)
746 goto out_up;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700747 err = shm_checkid(ns, shp, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748 if(err)
749 goto out_unlock_up;
750
Steve Grubb073115d2006-04-02 17:07:33 -0400751 err = audit_ipc_obj(&(shp->shm_perm));
752 if (err)
753 goto out_unlock_up;
754
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755 if (current->euid != shp->shm_perm.uid &&
756 current->euid != shp->shm_perm.cuid &&
757 !capable(CAP_SYS_ADMIN)) {
758 err=-EPERM;
759 goto out_unlock_up;
760 }
761
762 err = security_shm_shmctl(shp, cmd);
763 if (err)
764 goto out_unlock_up;
765
Kirill Korotaev4e982312006-10-02 02:18:22 -0700766 do_shm_rmid(ns, shp);
767 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 goto out;
769 }
770
771 case IPC_SET:
772 {
773 if (copy_shmid_from_user (&setbuf, buf, version)) {
774 err = -EFAULT;
775 goto out;
776 }
Kirill Korotaev4e982312006-10-02 02:18:22 -0700777 mutex_lock(&shm_ids(ns).mutex);
778 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 err=-EINVAL;
780 if(shp==NULL)
781 goto out_up;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700782 err = shm_checkid(ns, shp,shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 if(err)
784 goto out_unlock_up;
Steve Grubb073115d2006-04-02 17:07:33 -0400785 err = audit_ipc_obj(&(shp->shm_perm));
786 if (err)
787 goto out_unlock_up;
Linda Knippersac032212006-05-16 22:03:48 -0400788 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
Steve Grubb073115d2006-04-02 17:07:33 -0400789 if (err)
790 goto out_unlock_up;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791 err=-EPERM;
792 if (current->euid != shp->shm_perm.uid &&
793 current->euid != shp->shm_perm.cuid &&
794 !capable(CAP_SYS_ADMIN)) {
795 goto out_unlock_up;
796 }
797
798 err = security_shm_shmctl(shp, cmd);
799 if (err)
800 goto out_unlock_up;
801
802 shp->shm_perm.uid = setbuf.uid;
803 shp->shm_perm.gid = setbuf.gid;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800804 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 | (setbuf.mode & S_IRWXUGO);
806 shp->shm_ctim = get_seconds();
807 break;
808 }
809
810 default:
811 err = -EINVAL;
812 goto out;
813 }
814
815 err = 0;
816out_unlock_up:
817 shm_unlock(shp);
818out_up:
Kirill Korotaev4e982312006-10-02 02:18:22 -0700819 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 goto out;
821out_unlock:
822 shm_unlock(shp);
823out:
824 return err;
825}
826
827/*
828 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
829 *
830 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
831 * "raddr" thing points to kernel space, and there has to be a wrapper around
832 * this.
833 */
834long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
835{
836 struct shmid_kernel *shp;
837 unsigned long addr;
838 unsigned long size;
839 struct file * file;
840 int err;
841 unsigned long flags;
842 unsigned long prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 int acc_mode;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800844 unsigned long user_addr;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700845 struct ipc_namespace *ns;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800846 struct shm_file_data *sfd;
847 struct path path;
848 mode_t f_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800850 err = -EINVAL;
851 if (shmid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 goto out;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800853 else if ((addr = (ulong)shmaddr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 if (addr & (SHMLBA-1)) {
855 if (shmflg & SHM_RND)
856 addr &= ~(SHMLBA-1); /* round down */
857 else
858#ifndef __ARCH_FORCE_SHMLBA
859 if (addr & ~PAGE_MASK)
860#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800861 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 }
863 flags = MAP_SHARED | MAP_FIXED;
864 } else {
865 if ((shmflg & SHM_REMAP))
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800866 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867
868 flags = MAP_SHARED;
869 }
870
871 if (shmflg & SHM_RDONLY) {
872 prot = PROT_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 acc_mode = S_IRUGO;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800874 f_mode = FMODE_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 } else {
876 prot = PROT_READ | PROT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 acc_mode = S_IRUGO | S_IWUGO;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800878 f_mode = FMODE_READ | FMODE_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 }
880 if (shmflg & SHM_EXEC) {
881 prot |= PROT_EXEC;
882 acc_mode |= S_IXUGO;
883 }
884
885 /*
886 * We cannot rely on the fs check since SYSV IPC does have an
887 * additional creator id...
888 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700889 ns = current->nsproxy->ipc_ns;
890 shp = shm_lock(ns, shmid);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800891 if(shp == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 goto out;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800893
Kirill Korotaev4e982312006-10-02 02:18:22 -0700894 err = shm_checkid(ns, shp,shmid);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800895 if (err)
896 goto out_unlock;
897
898 err = -EACCES;
899 if (ipcperms(&shp->shm_perm, acc_mode))
900 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901
902 err = security_shm_shmat(shp, shmaddr, shmflg);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800903 if (err)
904 goto out_unlock;
905
906 path.dentry = dget(shp->shm_file->f_path.dentry);
907 path.mnt = mntget(shp->shm_file->f_path.mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908 shp->shm_nattch++;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800909 size = i_size_read(path.dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 shm_unlock(shp);
911
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800912 err = -ENOMEM;
913 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
914 if (!sfd)
915 goto out_put_path;
916
917 err = -ENOMEM;
918 file = get_empty_filp();
919 if (!file)
920 goto out_free;
921
922 file->f_op = &shm_file_operations;
923 file->private_data = sfd;
924 file->f_path = path;
925 file->f_mapping = shp->shm_file->f_mapping;
926 file->f_mode = f_mode;
927 sfd->id = shp->id;
928 sfd->ns = get_ipc_ns(ns);
929 sfd->file = shp->shm_file;
930 sfd->vm_ops = NULL;
931
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 down_write(&current->mm->mmap_sem);
933 if (addr && !(shmflg & SHM_REMAP)) {
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800934 err = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 if (find_vma_intersection(current->mm, addr, addr + size))
936 goto invalid;
937 /*
938 * If shm segment goes below stack, make sure there is some
939 * space left for the stack to grow (at least 4 pages).
940 */
941 if (addr < current->mm->start_stack &&
942 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
943 goto invalid;
944 }
945
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800946 user_addr = do_mmap (file, addr, size, prot, flags, 0);
947 *raddr = user_addr;
948 err = 0;
949 if (IS_ERR_VALUE(user_addr))
950 err = (long)user_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951invalid:
952 up_write(&current->mm->mmap_sem);
953
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800954 fput(file);
955
956out_nattch:
Kirill Korotaev4e982312006-10-02 02:18:22 -0700957 mutex_lock(&shm_ids(ns).mutex);
958 shp = shm_lock(ns, shmid);
Eric Sesterhenn9ba025f2006-04-02 13:42:42 +0200959 BUG_ON(!shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 shp->shm_nattch--;
961 if(shp->shm_nattch == 0 &&
Andrew Mortonb33291c2006-01-08 01:02:21 -0800962 shp->shm_perm.mode & SHM_DEST)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700963 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 else
965 shm_unlock(shp);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700966 mutex_unlock(&shm_ids(ns).mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968out:
969 return err;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800970
971out_unlock:
972 shm_unlock(shp);
973 goto out;
974
975out_free:
976 kfree(sfd);
977out_put_path:
978 dput(path.dentry);
979 mntput(path.mnt);
980 goto out_nattch;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981}
982
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -0700983asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
984{
985 unsigned long ret;
986 long err;
987
988 err = do_shmat(shmid, shmaddr, shmflg, &ret);
989 if (err)
990 return err;
991 force_successful_syscall_return();
992 return (long)ret;
993}
994
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995/*
996 * detach and kill segment if marked destroyed.
997 * The work is done in shm_close.
998 */
999asmlinkage long sys_shmdt(char __user *shmaddr)
1000{
1001 struct mm_struct *mm = current->mm;
1002 struct vm_area_struct *vma, *next;
1003 unsigned long addr = (unsigned long)shmaddr;
1004 loff_t size = 0;
1005 int retval = -EINVAL;
1006
Hugh Dickinsdf1e2fb2006-03-24 03:18:06 -08001007 if (addr & ~PAGE_MASK)
1008 return retval;
1009
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 down_write(&mm->mmap_sem);
1011
1012 /*
1013 * This function tries to be smart and unmap shm segments that
1014 * were modified by partial mlock or munmap calls:
1015 * - It first determines the size of the shm segment that should be
1016 * unmapped: It searches for a vma that is backed by shm and that
1017 * started at address shmaddr. It records it's size and then unmaps
1018 * it.
1019 * - Then it unmaps all shm vmas that started at shmaddr and that
1020 * are within the initially determined size.
1021 * Errors from do_munmap are ignored: the function only fails if
1022 * it's called with invalid parameters or if it's called to unmap
1023 * a part of a vma. Both calls in this function are for full vmas,
1024 * the parameters are directly copied from the vma itself and always
1025 * valid - therefore do_munmap cannot fail. (famous last words?)
1026 */
1027 /*
1028 * If it had been mremap()'d, the starting address would not
1029 * match the usual checks anyway. So assume all vma's are
1030 * above the starting address given.
1031 */
1032 vma = find_vma(mm, addr);
1033
1034 while (vma) {
1035 next = vma->vm_next;
1036
1037 /*
1038 * Check if the starting address would match, i.e. it's
1039 * a fragment created by mprotect() and/or munmap(), or it
1040 * otherwise it starts at this address with no hassles.
1041 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001042 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1044
1045
Josef Sipek6d630792006-12-08 02:37:11 -08001046 size = vma->vm_file->f_path.dentry->d_inode->i_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1048 /*
1049 * We discovered the size of the shm segment, so
1050 * break out of here and fall through to the next
1051 * loop that uses the size information to stop
1052 * searching for matching vma's.
1053 */
1054 retval = 0;
1055 vma = next;
1056 break;
1057 }
1058 vma = next;
1059 }
1060
1061 /*
1062 * We need look no further than the maximum address a fragment
1063 * could possibly have landed at. Also cast things to loff_t to
1064 * prevent overflows and make comparisions vs. equal-width types.
1065 */
KAMEZAWA Hiroyuki8e367092006-02-10 01:51:12 -08001066 size = PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001067 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1068 next = vma->vm_next;
1069
1070 /* finding a matching vma now does not alter retval */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001071 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1073
1074 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1075 vma = next;
1076 }
1077
1078 up_write(&mm->mmap_sem);
1079 return retval;
1080}
1081
1082#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -07001083static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084{
Mike Waychison19b49462005-09-06 15:17:10 -07001085 struct shmid_kernel *shp = it;
1086 char *format;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1089#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 -07001090
Mike Waychison19b49462005-09-06 15:17:10 -07001091 if (sizeof(size_t) <= sizeof(int))
1092 format = SMALL_STRING;
1093 else
1094 format = BIG_STRING;
1095 return seq_printf(s, format,
1096 shp->shm_perm.key,
1097 shp->id,
Andrew Mortonb33291c2006-01-08 01:02:21 -08001098 shp->shm_perm.mode,
Mike Waychison19b49462005-09-06 15:17:10 -07001099 shp->shm_segsz,
1100 shp->shm_cprid,
1101 shp->shm_lprid,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001102 shp->shm_nattch,
Mike Waychison19b49462005-09-06 15:17:10 -07001103 shp->shm_perm.uid,
1104 shp->shm_perm.gid,
1105 shp->shm_perm.cuid,
1106 shp->shm_perm.cgid,
1107 shp->shm_atim,
1108 shp->shm_dtim,
1109 shp->shm_ctim);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110}
1111#endif