blob: 7af1f05d59783cf3198771e9ea3945351deb7d7c [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/open.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7#include <linux/string.h>
8#include <linux/mm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07009#include <linux/file.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/quotaops.h>
Robert Love0eeca282005-07-12 17:06:03 -040011#include <linux/fsnotify.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/tty.h>
15#include <linux/namei.h>
16#include <linux/backing-dev.h>
Randy Dunlap16f7e0f2006-01-11 12:17:46 -080017#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/security.h>
19#include <linux/mount.h>
20#include <linux/vfs.h>
Ulrich Drepper5590ff02006-01-18 17:43:53 -080021#include <linux/fcntl.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <asm/uaccess.h>
23#include <linux/fs.h>
Yoav Zachef3daed2005-06-23 00:09:58 -070024#include <linux/personality.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/pagemap.h>
26#include <linux/syscalls.h>
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070027#include <linux/rcupdate.h>
Amy Griffis73241cc2005-11-03 16:00:25 +000028#include <linux/audit.h>
Amit Arora97ac7352007-07-17 21:42:44 -040029#include <linux/falloc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
David Howells726c3342006-06-23 02:02:58 -070031int vfs_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -070032{
33 int retval = -ENODEV;
34
David Howells726c3342006-06-23 02:02:58 -070035 if (dentry) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 retval = -ENOSYS;
David Howells726c3342006-06-23 02:02:58 -070037 if (dentry->d_sb->s_op->statfs) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070038 memset(buf, 0, sizeof(*buf));
David Howells726c3342006-06-23 02:02:58 -070039 retval = security_sb_statfs(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 if (retval)
41 return retval;
David Howells726c3342006-06-23 02:02:58 -070042 retval = dentry->d_sb->s_op->statfs(dentry, buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 if (retval == 0 && buf->f_frsize == 0)
44 buf->f_frsize = buf->f_bsize;
45 }
46 }
47 return retval;
48}
49
50EXPORT_SYMBOL(vfs_statfs);
51
David Howells726c3342006-06-23 02:02:58 -070052static int vfs_statfs_native(struct dentry *dentry, struct statfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -070053{
54 struct kstatfs st;
55 int retval;
56
David Howells726c3342006-06-23 02:02:58 -070057 retval = vfs_statfs(dentry, &st);
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 if (retval)
59 return retval;
60
61 if (sizeof(*buf) == sizeof(st))
62 memcpy(buf, &st, sizeof(st));
63 else {
64 if (sizeof buf->f_blocks == 4) {
65 if ((st.f_blocks | st.f_bfree | st.f_bavail) &
66 0xffffffff00000000ULL)
67 return -EOVERFLOW;
68 /*
69 * f_files and f_ffree may be -1; it's okay to stuff
70 * that into 32 bits
71 */
72 if (st.f_files != -1 &&
73 (st.f_files & 0xffffffff00000000ULL))
74 return -EOVERFLOW;
75 if (st.f_ffree != -1 &&
76 (st.f_ffree & 0xffffffff00000000ULL))
77 return -EOVERFLOW;
78 }
79
80 buf->f_type = st.f_type;
81 buf->f_bsize = st.f_bsize;
82 buf->f_blocks = st.f_blocks;
83 buf->f_bfree = st.f_bfree;
84 buf->f_bavail = st.f_bavail;
85 buf->f_files = st.f_files;
86 buf->f_ffree = st.f_ffree;
87 buf->f_fsid = st.f_fsid;
88 buf->f_namelen = st.f_namelen;
89 buf->f_frsize = st.f_frsize;
90 memset(buf->f_spare, 0, sizeof(buf->f_spare));
91 }
92 return 0;
93}
94
David Howells726c3342006-06-23 02:02:58 -070095static int vfs_statfs64(struct dentry *dentry, struct statfs64 *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -070096{
97 struct kstatfs st;
98 int retval;
99
David Howells726c3342006-06-23 02:02:58 -0700100 retval = vfs_statfs(dentry, &st);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 if (retval)
102 return retval;
103
104 if (sizeof(*buf) == sizeof(st))
105 memcpy(buf, &st, sizeof(st));
106 else {
107 buf->f_type = st.f_type;
108 buf->f_bsize = st.f_bsize;
109 buf->f_blocks = st.f_blocks;
110 buf->f_bfree = st.f_bfree;
111 buf->f_bavail = st.f_bavail;
112 buf->f_files = st.f_files;
113 buf->f_ffree = st.f_ffree;
114 buf->f_fsid = st.f_fsid;
115 buf->f_namelen = st.f_namelen;
116 buf->f_frsize = st.f_frsize;
117 memset(buf->f_spare, 0, sizeof(buf->f_spare));
118 }
119 return 0;
120}
121
122asmlinkage long sys_statfs(const char __user * path, struct statfs __user * buf)
123{
124 struct nameidata nd;
125 int error;
126
127 error = user_path_walk(path, &nd);
128 if (!error) {
129 struct statfs tmp;
Jan Blunck4ac91372008-02-14 19:34:32 -0800130 error = vfs_statfs_native(nd.path.dentry, &tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
132 error = -EFAULT;
Jan Blunck1d957f92008-02-14 19:34:35 -0800133 path_put(&nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 }
135 return error;
136}
137
138
139asmlinkage long sys_statfs64(const char __user *path, size_t sz, struct statfs64 __user *buf)
140{
141 struct nameidata nd;
142 long error;
143
144 if (sz != sizeof(*buf))
145 return -EINVAL;
146 error = user_path_walk(path, &nd);
147 if (!error) {
148 struct statfs64 tmp;
Jan Blunck4ac91372008-02-14 19:34:32 -0800149 error = vfs_statfs64(nd.path.dentry, &tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
151 error = -EFAULT;
Jan Blunck1d957f92008-02-14 19:34:35 -0800152 path_put(&nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 }
154 return error;
155}
156
157
158asmlinkage long sys_fstatfs(unsigned int fd, struct statfs __user * buf)
159{
160 struct file * file;
161 struct statfs tmp;
162 int error;
163
164 error = -EBADF;
165 file = fget(fd);
166 if (!file)
167 goto out;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800168 error = vfs_statfs_native(file->f_path.dentry, &tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
170 error = -EFAULT;
171 fput(file);
172out:
173 return error;
174}
175
176asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz, struct statfs64 __user *buf)
177{
178 struct file * file;
179 struct statfs64 tmp;
180 int error;
181
182 if (sz != sizeof(*buf))
183 return -EINVAL;
184
185 error = -EBADF;
186 file = fget(fd);
187 if (!file)
188 goto out;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800189 error = vfs_statfs64(file->f_path.dentry, &tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
191 error = -EFAULT;
192 fput(file);
193out:
194 return error;
195}
196
NeilBrown4a301312006-01-08 01:02:39 -0800197int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
198 struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199{
200 int err;
201 struct iattr newattrs;
202
203 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
204 if (length < 0)
205 return -EINVAL;
206
207 newattrs.ia_size = length;
NeilBrown4a301312006-01-08 01:02:39 -0800208 newattrs.ia_valid = ATTR_SIZE | time_attrs;
Miklos Szeredicc4e69d2005-11-07 00:59:49 -0800209 if (filp) {
210 newattrs.ia_file = filp;
211 newattrs.ia_valid |= ATTR_FILE;
212 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213
Linus Torvalds7b82dc02007-05-08 20:10:00 -0700214 /* Remove suid/sgid on truncate too */
215 newattrs.ia_valid |= should_remove_suid(dentry);
216
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800217 mutex_lock(&dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 err = notify_change(dentry, &newattrs);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800219 mutex_unlock(&dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 return err;
221}
222
Matt Mackallb01ec0e2006-01-08 01:05:20 -0800223static long do_sys_truncate(const char __user * path, loff_t length)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224{
225 struct nameidata nd;
226 struct inode * inode;
227 int error;
228
229 error = -EINVAL;
230 if (length < 0) /* sorry, but loff_t says... */
231 goto out;
232
233 error = user_path_walk(path, &nd);
234 if (error)
235 goto out;
Jan Blunck4ac91372008-02-14 19:34:32 -0800236 inode = nd.path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237
238 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
239 error = -EISDIR;
240 if (S_ISDIR(inode->i_mode))
241 goto dput_and_out;
242
243 error = -EINVAL;
244 if (!S_ISREG(inode->i_mode))
245 goto dput_and_out;
246
Dave Hansen9ac9b842008-02-15 14:37:52 -0800247 error = mnt_want_write(nd.path.mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 if (error)
249 goto dput_and_out;
250
Dave Hansen9ac9b842008-02-15 14:37:52 -0800251 error = vfs_permission(&nd, MAY_WRITE);
252 if (error)
253 goto mnt_drop_write_and_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
255 error = -EPERM;
256 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
Dave Hansen9ac9b842008-02-15 14:37:52 -0800257 goto mnt_drop_write_and_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 error = get_write_access(inode);
260 if (error)
Dave Hansen9ac9b842008-02-15 14:37:52 -0800261 goto mnt_drop_write_and_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262
david m. richter97003822007-07-31 00:39:12 -0700263 /*
264 * Make sure that there are no leases. get_write_access() protects
265 * against the truncate racing with a lease-granting setlease().
266 */
267 error = break_lease(inode, FMODE_WRITE);
268 if (error)
269 goto put_write_and_out;
270
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 error = locks_verify_truncate(inode, NULL, length);
272 if (!error) {
273 DQUOT_INIT(inode);
Jan Blunck4ac91372008-02-14 19:34:32 -0800274 error = do_truncate(nd.path.dentry, length, 0, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276
david m. richter97003822007-07-31 00:39:12 -0700277put_write_and_out:
278 put_write_access(inode);
Dave Hansen9ac9b842008-02-15 14:37:52 -0800279mnt_drop_write_and_out:
280 mnt_drop_write(nd.path.mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281dput_and_out:
Jan Blunck1d957f92008-02-14 19:34:35 -0800282 path_put(&nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283out:
284 return error;
285}
286
287asmlinkage long sys_truncate(const char __user * path, unsigned long length)
288{
289 /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */
290 return do_sys_truncate(path, (long)length);
291}
292
Matt Mackallb01ec0e2006-01-08 01:05:20 -0800293static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294{
295 struct inode * inode;
296 struct dentry *dentry;
297 struct file * file;
298 int error;
299
300 error = -EINVAL;
301 if (length < 0)
302 goto out;
303 error = -EBADF;
304 file = fget(fd);
305 if (!file)
306 goto out;
307
308 /* explicitly opened as large or we are on 64-bit box */
309 if (file->f_flags & O_LARGEFILE)
310 small = 0;
311
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800312 dentry = file->f_path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 inode = dentry->d_inode;
314 error = -EINVAL;
315 if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE))
316 goto out_putf;
317
318 error = -EINVAL;
319 /* Cannot ftruncate over 2^31 bytes without large file support */
320 if (small && length > MAX_NON_LFS)
321 goto out_putf;
322
323 error = -EPERM;
324 if (IS_APPEND(inode))
325 goto out_putf;
326
327 error = locks_verify_truncate(inode, file, length);
328 if (!error)
Peter Staubach6e656be2006-06-25 05:48:36 -0700329 error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330out_putf:
331 fput(file);
332out:
333 return error;
334}
335
336asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length)
337{
Linus Torvalds0a489cb2006-04-18 13:02:48 -0700338 long ret = do_sys_ftruncate(fd, length, 1);
Linus Torvalds385910f2006-04-18 13:22:59 -0700339 /* avoid REGPARM breakage on x86: */
Roland McGrath54a01512008-04-10 15:37:38 -0700340 asmlinkage_protect(2, ret, fd, length);
Linus Torvalds0a489cb2006-04-18 13:02:48 -0700341 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342}
343
344/* LFS versions of truncate are only needed on 32 bit machines */
345#if BITS_PER_LONG == 32
346asmlinkage long sys_truncate64(const char __user * path, loff_t length)
347{
348 return do_sys_truncate(path, length);
349}
350
351asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length)
352{
Linus Torvalds0a489cb2006-04-18 13:02:48 -0700353 long ret = do_sys_ftruncate(fd, length, 0);
Linus Torvalds385910f2006-04-18 13:22:59 -0700354 /* avoid REGPARM breakage on x86: */
Roland McGrath54a01512008-04-10 15:37:38 -0700355 asmlinkage_protect(2, ret, fd, length);
Linus Torvalds0a489cb2006-04-18 13:02:48 -0700356 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357}
358#endif
359
Amit Arora97ac7352007-07-17 21:42:44 -0400360asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len)
361{
362 struct file *file;
363 struct inode *inode;
364 long ret = -EINVAL;
365
366 if (offset < 0 || len <= 0)
367 goto out;
368
369 /* Return error if mode is not supported */
370 ret = -EOPNOTSUPP;
371 if (mode && !(mode & FALLOC_FL_KEEP_SIZE))
372 goto out;
373
374 ret = -EBADF;
375 file = fget(fd);
376 if (!file)
377 goto out;
378 if (!(file->f_mode & FMODE_WRITE))
379 goto out_fput;
380 /*
381 * Revalidate the write permissions, in case security policy has
382 * changed since the files were opened.
383 */
384 ret = security_file_permission(file, MAY_WRITE);
385 if (ret)
386 goto out_fput;
387
388 inode = file->f_path.dentry->d_inode;
389
390 ret = -ESPIPE;
391 if (S_ISFIFO(inode->i_mode))
392 goto out_fput;
393
394 ret = -ENODEV;
395 /*
396 * Let individual file system decide if it supports preallocation
397 * for directories or not.
398 */
399 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
400 goto out_fput;
401
402 ret = -EFBIG;
403 /* Check for wrap through zero too */
404 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
405 goto out_fput;
406
407 if (inode->i_op && inode->i_op->fallocate)
408 ret = inode->i_op->fallocate(inode, mode, offset, len);
409 else
Ulrich Drepper0d786d42007-07-23 18:43:46 -0700410 ret = -EOPNOTSUPP;
Amit Arora97ac7352007-07-17 21:42:44 -0400411
412out_fput:
413 fput(file);
414out:
415 return ret;
416}
417
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418/*
419 * access() needs to use the real uid/gid, not the effective uid/gid.
420 * We do this by temporarily clearing all FS-related capabilities and
421 * switching the fsuid/fsgid around to the real ones.
422 */
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800423asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424{
425 struct nameidata nd;
426 int old_fsuid, old_fsgid;
427 kernel_cap_t old_cap;
428 int res;
429
430 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
431 return -EINVAL;
432
433 old_fsuid = current->fsuid;
434 old_fsgid = current->fsgid;
435 old_cap = current->cap_effective;
436
437 current->fsuid = current->uid;
438 current->fsgid = current->gid;
439
440 /*
441 * Clear the capabilities if we switch to a non-root user
442 *
443 * FIXME: There is a race here against sys_capset. The
444 * capabilities can change yet we will restore the old
445 * value below. We should hold task_capabilities_lock,
446 * but we cannot because user_path_walk can sleep.
447 */
448 if (current->uid)
449 cap_clear(current->cap_effective);
450 else
451 current->cap_effective = current->cap_permitted;
452
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800453 res = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd);
Dave Hansen6902d922006-09-30 23:29:01 -0700454 if (res)
455 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456
Dave Hansen6902d922006-09-30 23:29:01 -0700457 res = vfs_permission(&nd, mode);
458 /* SuS v2 requires we report a read only fs too */
459 if(res || !(mode & S_IWOTH) ||
Jan Blunck4ac91372008-02-14 19:34:32 -0800460 special_file(nd.path.dentry->d_inode->i_mode))
Dave Hansen6902d922006-09-30 23:29:01 -0700461 goto out_path_release;
Dave Hansen2f676cb2008-02-15 14:37:55 -0800462 /*
463 * This is a rare case where using __mnt_is_readonly()
464 * is OK without a mnt_want/drop_write() pair. Since
465 * no actual write to the fs is performed here, we do
466 * not need to telegraph to that to anyone.
467 *
468 * By doing this, we accept that this access is
469 * inherently racy and know that the fs may change
470 * state before we even see this result.
471 */
472 if (__mnt_is_readonly(nd.path.mnt))
Dave Hansen6902d922006-09-30 23:29:01 -0700473 res = -EROFS;
474
475out_path_release:
Jan Blunck1d957f92008-02-14 19:34:35 -0800476 path_put(&nd.path);
Dave Hansen6902d922006-09-30 23:29:01 -0700477out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 current->fsuid = old_fsuid;
479 current->fsgid = old_fsgid;
480 current->cap_effective = old_cap;
481
482 return res;
483}
484
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800485asmlinkage long sys_access(const char __user *filename, int mode)
486{
487 return sys_faccessat(AT_FDCWD, filename, mode);
488}
489
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490asmlinkage long sys_chdir(const char __user * filename)
491{
492 struct nameidata nd;
493 int error;
494
Miklos Szeredi650a8982006-09-29 01:59:35 -0700495 error = __user_walk(filename,
496 LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_CHDIR, &nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 if (error)
498 goto out;
499
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800500 error = vfs_permission(&nd, MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 if (error)
502 goto dput_and_out;
503
Jan Blunckac748a02008-02-14 19:34:39 -0800504 set_fs_pwd(current->fs, &nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505
506dput_and_out:
Jan Blunck1d957f92008-02-14 19:34:35 -0800507 path_put(&nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508out:
509 return error;
510}
511
512asmlinkage long sys_fchdir(unsigned int fd)
513{
514 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 int error;
517
518 error = -EBADF;
519 file = fget(fd);
520 if (!file)
521 goto out;
522
Jan Blunckac748a02008-02-14 19:34:39 -0800523 inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524
525 error = -ENOTDIR;
526 if (!S_ISDIR(inode->i_mode))
527 goto out_putf;
528
Christoph Hellwig8c744fb2005-11-08 21:35:04 -0800529 error = file_permission(file, MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 if (!error)
Jan Blunckac748a02008-02-14 19:34:39 -0800531 set_fs_pwd(current->fs, &file->f_path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532out_putf:
533 fput(file);
534out:
535 return error;
536}
537
538asmlinkage long sys_chroot(const char __user * filename)
539{
540 struct nameidata nd;
541 int error;
542
543 error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd);
544 if (error)
545 goto out;
546
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800547 error = vfs_permission(&nd, MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 if (error)
549 goto dput_and_out;
550
551 error = -EPERM;
552 if (!capable(CAP_SYS_CHROOT))
553 goto dput_and_out;
554
Jan Blunckac748a02008-02-14 19:34:39 -0800555 set_fs_root(current->fs, &nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 set_fs_altroot();
557 error = 0;
558dput_and_out:
Jan Blunck1d957f92008-02-14 19:34:35 -0800559 path_put(&nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560out:
561 return error;
562}
563
564asmlinkage long sys_fchmod(unsigned int fd, mode_t mode)
565{
566 struct inode * inode;
567 struct dentry * dentry;
568 struct file * file;
569 int err = -EBADF;
570 struct iattr newattrs;
571
572 file = fget(fd);
573 if (!file)
574 goto out;
575
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800576 dentry = file->f_path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 inode = dentry->d_inode;
578
Al Viro5a190ae2007-06-07 12:19:32 -0400579 audit_inode(NULL, dentry);
Amy Griffis73241cc2005-11-03 16:00:25 +0000580
Dave Hansen2af482a2008-02-15 14:37:50 -0800581 err = mnt_want_write(file->f_path.mnt);
582 if (err)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 goto out_putf;
584 err = -EPERM;
585 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
Dave Hansen2af482a2008-02-15 14:37:50 -0800586 goto out_drop_write;
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800587 mutex_lock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 if (mode == (mode_t) -1)
589 mode = inode->i_mode;
590 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
591 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
592 err = notify_change(dentry, &newattrs);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800593 mutex_unlock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594
Dave Hansen2af482a2008-02-15 14:37:50 -0800595out_drop_write:
596 mnt_drop_write(file->f_path.mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597out_putf:
598 fput(file);
599out:
600 return err;
601}
602
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800603asmlinkage long sys_fchmodat(int dfd, const char __user *filename,
604 mode_t mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605{
606 struct nameidata nd;
607 struct inode * inode;
608 int error;
609 struct iattr newattrs;
610
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800611 error = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW, &nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 if (error)
613 goto out;
Jan Blunck4ac91372008-02-14 19:34:32 -0800614 inode = nd.path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615
Dave Hansen2af482a2008-02-15 14:37:50 -0800616 error = mnt_want_write(nd.path.mnt);
617 if (error)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 goto dput_and_out;
619
620 error = -EPERM;
621 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
Dave Hansen2af482a2008-02-15 14:37:50 -0800622 goto out_drop_write;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800624 mutex_lock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 if (mode == (mode_t) -1)
626 mode = inode->i_mode;
627 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
628 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
Jan Blunck4ac91372008-02-14 19:34:32 -0800629 error = notify_change(nd.path.dentry, &newattrs);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800630 mutex_unlock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631
Dave Hansen2af482a2008-02-15 14:37:50 -0800632out_drop_write:
633 mnt_drop_write(nd.path.mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634dput_and_out:
Jan Blunck1d957f92008-02-14 19:34:35 -0800635 path_put(&nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636out:
637 return error;
638}
639
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800640asmlinkage long sys_chmod(const char __user *filename, mode_t mode)
641{
642 return sys_fchmodat(AT_FDCWD, filename, mode);
643}
644
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
646{
647 struct inode * inode;
648 int error;
649 struct iattr newattrs;
650
651 error = -ENOENT;
652 if (!(inode = dentry->d_inode)) {
653 printk(KERN_ERR "chown_common: NULL inode\n");
654 goto out;
655 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 error = -EPERM;
657 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
658 goto out;
659 newattrs.ia_valid = ATTR_CTIME;
660 if (user != (uid_t) -1) {
661 newattrs.ia_valid |= ATTR_UID;
662 newattrs.ia_uid = user;
663 }
664 if (group != (gid_t) -1) {
665 newattrs.ia_valid |= ATTR_GID;
666 newattrs.ia_gid = group;
667 }
668 if (!S_ISDIR(inode->i_mode))
Serge E. Hallynb5376772007-10-16 23:31:36 -0700669 newattrs.ia_valid |=
670 ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800671 mutex_lock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 error = notify_change(dentry, &newattrs);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800673 mutex_unlock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674out:
675 return error;
676}
677
678asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group)
679{
680 struct nameidata nd;
681 int error;
682
683 error = user_path_walk(filename, &nd);
Dave Hansen6902d922006-09-30 23:29:01 -0700684 if (error)
685 goto out;
Dave Hansen2af482a2008-02-15 14:37:50 -0800686 error = mnt_want_write(nd.path.mnt);
687 if (error)
688 goto out_release;
Jan Blunck4ac91372008-02-14 19:34:32 -0800689 error = chown_common(nd.path.dentry, user, group);
Dave Hansen2af482a2008-02-15 14:37:50 -0800690 mnt_drop_write(nd.path.mnt);
691out_release:
Jan Blunck1d957f92008-02-14 19:34:35 -0800692 path_put(&nd.path);
Dave Hansen6902d922006-09-30 23:29:01 -0700693out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 return error;
695}
696
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800697asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user,
698 gid_t group, int flag)
699{
700 struct nameidata nd;
701 int error = -EINVAL;
702 int follow;
703
704 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
705 goto out;
706
707 follow = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
708 error = __user_walk_fd(dfd, filename, follow, &nd);
Dave Hansen6902d922006-09-30 23:29:01 -0700709 if (error)
710 goto out;
Dave Hansen2af482a2008-02-15 14:37:50 -0800711 error = mnt_want_write(nd.path.mnt);
712 if (error)
713 goto out_release;
Jan Blunck4ac91372008-02-14 19:34:32 -0800714 error = chown_common(nd.path.dentry, user, group);
Dave Hansen2af482a2008-02-15 14:37:50 -0800715 mnt_drop_write(nd.path.mnt);
716out_release:
Jan Blunck1d957f92008-02-14 19:34:35 -0800717 path_put(&nd.path);
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800718out:
719 return error;
720}
721
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group)
723{
724 struct nameidata nd;
725 int error;
726
727 error = user_path_walk_link(filename, &nd);
Dave Hansen6902d922006-09-30 23:29:01 -0700728 if (error)
729 goto out;
Dave Hansen2af482a2008-02-15 14:37:50 -0800730 error = mnt_want_write(nd.path.mnt);
731 if (error)
732 goto out_release;
Jan Blunck4ac91372008-02-14 19:34:32 -0800733 error = chown_common(nd.path.dentry, user, group);
Dave Hansen2af482a2008-02-15 14:37:50 -0800734 mnt_drop_write(nd.path.mnt);
735out_release:
Jan Blunck1d957f92008-02-14 19:34:35 -0800736 path_put(&nd.path);
Dave Hansen6902d922006-09-30 23:29:01 -0700737out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 return error;
739}
740
741
742asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group)
743{
744 struct file * file;
745 int error = -EBADF;
Dave Hansen6902d922006-09-30 23:29:01 -0700746 struct dentry * dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747
748 file = fget(fd);
Dave Hansen6902d922006-09-30 23:29:01 -0700749 if (!file)
750 goto out;
751
Dave Hansen2af482a2008-02-15 14:37:50 -0800752 error = mnt_want_write(file->f_path.mnt);
753 if (error)
754 goto out_fput;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800755 dentry = file->f_path.dentry;
Al Viro5a190ae2007-06-07 12:19:32 -0400756 audit_inode(NULL, dentry);
Dave Hansen6902d922006-09-30 23:29:01 -0700757 error = chown_common(dentry, user, group);
Dave Hansen2af482a2008-02-15 14:37:50 -0800758 mnt_drop_write(file->f_path.mnt);
759out_fput:
Dave Hansen6902d922006-09-30 23:29:01 -0700760 fput(file);
761out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 return error;
763}
764
Dave Hansen4a3fd212008-02-15 14:37:48 -0800765/*
766 * You have to be very careful that these write
767 * counts get cleaned up in error cases and
768 * upon __fput(). This should probably never
769 * be called outside of __dentry_open().
770 */
771static inline int __get_file_write_access(struct inode *inode,
772 struct vfsmount *mnt)
773{
774 int error;
775 error = get_write_access(inode);
776 if (error)
777 return error;
778 /*
779 * Do not take mount writer counts on
780 * special files since no writes to
781 * the mount itself will occur.
782 */
783 if (!special_file(inode->i_mode)) {
784 /*
785 * Balanced in __fput()
786 */
787 error = mnt_want_write(mnt);
788 if (error)
789 put_write_access(inode);
790 }
791 return error;
792}
793
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700794static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
Trond Myklebust834f2a42005-10-18 14:20:16 -0700795 int flags, struct file *f,
796 int (*open)(struct inode *, struct file *))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798 struct inode *inode;
799 int error;
800
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 f->f_flags = flags;
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700802 f->f_mode = ((flags+1) & O_ACCMODE) | FMODE_LSEEK |
803 FMODE_PREAD | FMODE_PWRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 inode = dentry->d_inode;
805 if (f->f_mode & FMODE_WRITE) {
Dave Hansen4a3fd212008-02-15 14:37:48 -0800806 error = __get_file_write_access(inode, mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 if (error)
808 goto cleanup_file;
Dave Hansenad775f52008-02-15 14:38:01 -0800809 if (!special_file(inode->i_mode))
810 file_take_write(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 }
812
813 f->f_mapping = inode->i_mapping;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800814 f->f_path.dentry = dentry;
815 f->f_path.mnt = mnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 f->f_pos = 0;
817 f->f_op = fops_get(inode->i_fop);
818 file_move(f, &inode->i_sb->s_files);
819
Yuichi Nakamura788e7dd2007-09-14 09:27:07 +0900820 error = security_dentry_open(f);
821 if (error)
822 goto cleanup_all;
823
Trond Myklebust834f2a42005-10-18 14:20:16 -0700824 if (!open && f->f_op)
825 open = f->f_op->open;
826 if (open) {
827 error = open(inode, f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 if (error)
829 goto cleanup_all;
830 }
Trond Myklebust834f2a42005-10-18 14:20:16 -0700831
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
833
834 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
835
836 /* NB: we're sure to have correct a_ops only after f_op->open */
837 if (f->f_flags & O_DIRECT) {
Carsten Otteceffc072005-06-23 22:05:25 -0700838 if (!f->f_mapping->a_ops ||
839 ((!f->f_mapping->a_ops->direct_IO) &&
Nick Piggin70688e42008-04-28 02:13:02 -0700840 (!f->f_mapping->a_ops->get_xip_mem))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 fput(f);
842 f = ERR_PTR(-EINVAL);
843 }
844 }
845
846 return f;
847
848cleanup_all:
849 fops_put(f->f_op);
Dave Hansen4a3fd212008-02-15 14:37:48 -0800850 if (f->f_mode & FMODE_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 put_write_access(inode);
Dave Hansenad775f52008-02-15 14:38:01 -0800852 if (!special_file(inode->i_mode)) {
853 /*
854 * We don't consider this a real
855 * mnt_want/drop_write() pair
856 * because it all happenend right
857 * here, so just reset the state.
858 */
859 file_reset_write(f);
Dave Hansen4a3fd212008-02-15 14:37:48 -0800860 mnt_drop_write(mnt);
Dave Hansenad775f52008-02-15 14:38:01 -0800861 }
Dave Hansen4a3fd212008-02-15 14:37:48 -0800862 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 file_kill(f);
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800864 f->f_path.dentry = NULL;
865 f->f_path.mnt = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866cleanup_file:
867 put_filp(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868 dput(dentry);
869 mntput(mnt);
870 return ERR_PTR(error);
871}
872
Trond Myklebust834f2a42005-10-18 14:20:16 -0700873/**
874 * lookup_instantiate_filp - instantiates the open intent filp
875 * @nd: pointer to nameidata
876 * @dentry: pointer to dentry
877 * @open: open callback
878 *
879 * Helper for filesystems that want to use lookup open intents and pass back
880 * a fully instantiated struct file to the caller.
881 * This function is meant to be called from within a filesystem's
882 * lookup method.
Oleg Drokin9a56c212006-03-25 03:07:02 -0800883 * Beware of calling it for non-regular files! Those ->open methods might block
884 * (e.g. in fifo_open), leaving you with parent locked (and in case of fifo,
885 * leading to a deadlock, as nobody can open that fifo anymore, because
886 * another process to open fifo will block on locked parent when doing lookup).
Trond Myklebust834f2a42005-10-18 14:20:16 -0700887 * Note that in case of error, nd->intent.open.file is destroyed, but the
888 * path information remains valid.
889 * If the open callback is set to NULL, then the standard f_op->open()
890 * filesystem callback is substituted.
891 */
892struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
893 int (*open)(struct inode *, struct file *))
894{
895 if (IS_ERR(nd->intent.open.file))
896 goto out;
897 if (IS_ERR(dentry))
898 goto out_err;
Jan Blunck4ac91372008-02-14 19:34:32 -0800899 nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->path.mnt),
Trond Myklebust834f2a42005-10-18 14:20:16 -0700900 nd->intent.open.flags - 1,
901 nd->intent.open.file,
902 open);
903out:
904 return nd->intent.open.file;
905out_err:
906 release_open_intent(nd);
907 nd->intent.open.file = (struct file *)dentry;
908 goto out;
909}
910EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
911
912/**
913 * nameidata_to_filp - convert a nameidata to an open filp.
914 * @nd: pointer to nameidata
915 * @flags: open flags
916 *
917 * Note that this function destroys the original nameidata
918 */
919struct file *nameidata_to_filp(struct nameidata *nd, int flags)
920{
921 struct file *filp;
922
923 /* Pick up the filp from the open intent */
924 filp = nd->intent.open.file;
925 /* Has the filesystem initialised the file for us? */
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800926 if (filp->f_path.dentry == NULL)
Jan Blunck4ac91372008-02-14 19:34:32 -0800927 filp = __dentry_open(nd->path.dentry, nd->path.mnt, flags, filp,
928 NULL);
Trond Myklebust834f2a42005-10-18 14:20:16 -0700929 else
Jan Blunck1d957f92008-02-14 19:34:35 -0800930 path_put(&nd->path);
Trond Myklebust834f2a42005-10-18 14:20:16 -0700931 return filp;
932}
933
Peter Staubach6fdcc212005-11-07 00:59:42 -0800934/*
935 * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
936 * error.
937 */
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700938struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
939{
940 int error;
941 struct file *f;
942
Christoph Hellwig322ee5b2008-02-15 14:37:24 -0800943 /*
944 * We must always pass in a valid mount pointer. Historically
945 * callers got away with not passing it, but we must enforce this at
946 * the earliest possible point now to avoid strange problems deep in the
947 * filesystem stack.
948 */
949 if (!mnt) {
950 printk(KERN_WARNING "%s called with NULL vfsmount\n", __func__);
951 dump_stack();
952 return ERR_PTR(-EINVAL);
953 }
954
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700955 error = -ENFILE;
956 f = get_empty_filp();
Peter Staubach6fdcc212005-11-07 00:59:42 -0800957 if (f == NULL) {
958 dput(dentry);
959 mntput(mnt);
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700960 return ERR_PTR(error);
Peter Staubach6fdcc212005-11-07 00:59:42 -0800961 }
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700962
Trond Myklebust834f2a42005-10-18 14:20:16 -0700963 return __dentry_open(dentry, mnt, flags, f, NULL);
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700964}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965EXPORT_SYMBOL(dentry_open);
966
967/*
968 * Find an empty file descriptor entry, and mark it busy.
969 */
Ulrich Drepper4a195422007-07-15 23:40:34 -0700970int get_unused_fd_flags(int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971{
972 struct files_struct * files = current->files;
973 int fd, error;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700974 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975
976 error = -EMFILE;
977 spin_lock(&files->file_lock);
978
979repeat:
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700980 fdt = files_fdtable(files);
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800981 fd = find_next_zero_bit(fdt->open_fds->fds_bits, fdt->max_fds,
Eric Dumazet0c9e63f2006-03-23 03:00:12 -0800982 files->next_fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983
984 /*
985 * N.B. For clone tasks sharing a files structure, this test
986 * will limit the total number of files that can be opened.
987 */
988 if (fd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
989 goto out;
990
991 /* Do we need to expand the fd array or fd set? */
992 error = expand_files(files, fd);
993 if (error < 0)
994 goto out;
995
996 if (error) {
997 /*
998 * If we needed to expand the fs array we
999 * might have blocked - try again.
1000 */
1001 error = -EMFILE;
1002 goto repeat;
1003 }
1004
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001005 FD_SET(fd, fdt->open_fds);
Ulrich Drepperf23513e2007-07-15 23:40:32 -07001006 if (flags & O_CLOEXEC)
1007 FD_SET(fd, fdt->close_on_exec);
1008 else
1009 FD_CLR(fd, fdt->close_on_exec);
Eric Dumazet0c9e63f2006-03-23 03:00:12 -08001010 files->next_fd = fd + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011#if 1
1012 /* Sanity check */
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001013 if (fdt->fd[fd] != NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd);
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001015 fdt->fd[fd] = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016 }
1017#endif
1018 error = fd;
1019
1020out:
1021 spin_unlock(&files->file_lock);
1022 return error;
1023}
1024
Ulrich Drepperf23513e2007-07-15 23:40:32 -07001025int get_unused_fd(void)
1026{
1027 return get_unused_fd_flags(0);
1028}
1029
Linus Torvalds1da177e2005-04-16 15:20:36 -07001030EXPORT_SYMBOL(get_unused_fd);
1031
Matt Mackallb01ec0e2006-01-08 01:05:20 -08001032static void __put_unused_fd(struct files_struct *files, unsigned int fd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033{
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001034 struct fdtable *fdt = files_fdtable(files);
1035 __FD_CLR(fd, fdt->open_fds);
Eric Dumazet0c9e63f2006-03-23 03:00:12 -08001036 if (fd < files->next_fd)
1037 files->next_fd = fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038}
1039
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -08001040void put_unused_fd(unsigned int fd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041{
1042 struct files_struct *files = current->files;
1043 spin_lock(&files->file_lock);
1044 __put_unused_fd(files, fd);
1045 spin_unlock(&files->file_lock);
1046}
1047
1048EXPORT_SYMBOL(put_unused_fd);
1049
1050/*
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001051 * Install a file pointer in the fd array.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052 *
1053 * The VFS is full of places where we drop the files lock between
1054 * setting the open_fds bitmap and installing the file in the file
1055 * array. At any such point, we are vulnerable to a dup2() race
1056 * installing a file in the array before us. We need to detect this and
1057 * fput() the struct file we are about to overwrite in this case.
1058 *
1059 * It should never happen - if we allow dup2() do it, _really_ bad things
1060 * will follow.
1061 */
1062
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -08001063void fd_install(unsigned int fd, struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064{
1065 struct files_struct *files = current->files;
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001066 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001067 spin_lock(&files->file_lock);
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001068 fdt = files_fdtable(files);
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -07001069 BUG_ON(fdt->fd[fd] != NULL);
1070 rcu_assign_pointer(fdt->fd[fd], file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001071 spin_unlock(&files->file_lock);
1072}
1073
1074EXPORT_SYMBOL(fd_install);
1075
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001076long do_sys_open(int dfd, const char __user *filename, int flags, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077{
Miklos Szeredie922efc2005-09-06 15:18:25 -07001078 char *tmp = getname(filename);
1079 int fd = PTR_ERR(tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081 if (!IS_ERR(tmp)) {
Ulrich Drepperf23513e2007-07-15 23:40:32 -07001082 fd = get_unused_fd_flags(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 if (fd >= 0) {
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001084 struct file *f = do_filp_open(dfd, tmp, flags, mode);
Telemaque Ndizihiwefed2fc12005-06-23 00:10:33 -07001085 if (IS_ERR(f)) {
1086 put_unused_fd(fd);
1087 fd = PTR_ERR(f);
1088 } else {
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001089 fsnotify_open(f->f_path.dentry);
Telemaque Ndizihiwefed2fc12005-06-23 00:10:33 -07001090 fd_install(fd, f);
1091 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093 putname(tmp);
1094 }
1095 return fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096}
Miklos Szeredie922efc2005-09-06 15:18:25 -07001097
1098asmlinkage long sys_open(const char __user *filename, int flags, int mode)
1099{
Linus Torvalds385910f2006-04-18 13:22:59 -07001100 long ret;
1101
Miklos Szeredie922efc2005-09-06 15:18:25 -07001102 if (force_o_largefile())
1103 flags |= O_LARGEFILE;
1104
Linus Torvalds385910f2006-04-18 13:22:59 -07001105 ret = do_sys_open(AT_FDCWD, filename, flags, mode);
1106 /* avoid REGPARM breakage on x86: */
Roland McGrath54a01512008-04-10 15:37:38 -07001107 asmlinkage_protect(3, ret, filename, flags, mode);
Linus Torvalds385910f2006-04-18 13:22:59 -07001108 return ret;
Miklos Szeredie922efc2005-09-06 15:18:25 -07001109}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001111asmlinkage long sys_openat(int dfd, const char __user *filename, int flags,
1112 int mode)
1113{
Linus Torvalds385910f2006-04-18 13:22:59 -07001114 long ret;
1115
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001116 if (force_o_largefile())
1117 flags |= O_LARGEFILE;
1118
Linus Torvalds385910f2006-04-18 13:22:59 -07001119 ret = do_sys_open(dfd, filename, flags, mode);
1120 /* avoid REGPARM breakage on x86: */
Roland McGrath54a01512008-04-10 15:37:38 -07001121 asmlinkage_protect(4, ret, dfd, filename, flags, mode);
Linus Torvalds385910f2006-04-18 13:22:59 -07001122 return ret;
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001123}
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001124
Linus Torvalds1da177e2005-04-16 15:20:36 -07001125#ifndef __alpha__
1126
1127/*
1128 * For backward compatibility? Maybe this should be moved
1129 * into arch/i386 instead?
1130 */
1131asmlinkage long sys_creat(const char __user * pathname, int mode)
1132{
1133 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
1134}
1135
1136#endif
1137
1138/*
1139 * "id" is the POSIX thread ID. We use the
1140 * files pointer for this..
1141 */
1142int filp_close(struct file *filp, fl_owner_t id)
1143{
Christoph Lameter45778ca2005-06-23 00:10:17 -07001144 int retval = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001145
1146 if (!file_count(filp)) {
1147 printk(KERN_ERR "VFS: Close: file count is 0\n");
Christoph Lameter45778ca2005-06-23 00:10:17 -07001148 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 }
1150
Christoph Lameter45778ca2005-06-23 00:10:17 -07001151 if (filp->f_op && filp->f_op->flush)
Miklos Szeredi75e1fcc2006-06-23 02:05:12 -07001152 retval = filp->f_op->flush(filp, id);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153
1154 dnotify_flush(filp, id);
1155 locks_remove_posix(filp, id);
1156 fput(filp);
1157 return retval;
1158}
1159
1160EXPORT_SYMBOL(filp_close);
1161
1162/*
1163 * Careful here! We test whether the file pointer is NULL before
1164 * releasing the fd. This ensures that one clone task can't release
1165 * an fd while another clone is opening it.
1166 */
1167asmlinkage long sys_close(unsigned int fd)
1168{
1169 struct file * filp;
1170 struct files_struct *files = current->files;
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001171 struct fdtable *fdt;
Ernie Petridesee731f42006-09-29 02:00:13 -07001172 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173
1174 spin_lock(&files->file_lock);
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001175 fdt = files_fdtable(files);
1176 if (fd >= fdt->max_fds)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 goto out_unlock;
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001178 filp = fdt->fd[fd];
Linus Torvalds1da177e2005-04-16 15:20:36 -07001179 if (!filp)
1180 goto out_unlock;
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -07001181 rcu_assign_pointer(fdt->fd[fd], NULL);
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001182 FD_CLR(fd, fdt->close_on_exec);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001183 __put_unused_fd(files, fd);
1184 spin_unlock(&files->file_lock);
Ernie Petridesee731f42006-09-29 02:00:13 -07001185 retval = filp_close(filp, files);
1186
1187 /* can't restart close syscall because file table entry was cleared */
1188 if (unlikely(retval == -ERESTARTSYS ||
1189 retval == -ERESTARTNOINTR ||
1190 retval == -ERESTARTNOHAND ||
1191 retval == -ERESTART_RESTARTBLOCK))
1192 retval = -EINTR;
1193
1194 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195
1196out_unlock:
1197 spin_unlock(&files->file_lock);
1198 return -EBADF;
1199}
1200
1201EXPORT_SYMBOL(sys_close);
1202
1203/*
1204 * This routine simulates a hangup on the tty, to arrange that users
1205 * are given clean terminals at login time.
1206 */
1207asmlinkage long sys_vhangup(void)
1208{
1209 if (capable(CAP_SYS_TTY_CONFIG)) {
Peter Zijlstra24ec8392006-12-08 02:36:04 -08001210 /* XXX: this needs locking */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211 tty_vhangup(current->signal->tty);
1212 return 0;
1213 }
1214 return -EPERM;
1215}
1216
1217/*
1218 * Called when an inode is about to be open.
1219 * We use this to disallow opening large files on 32bit systems if
1220 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1221 * on this flag in sys_open.
1222 */
1223int generic_file_open(struct inode * inode, struct file * filp)
1224{
1225 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
Alan Coxa9c62a12007-10-16 23:30:22 -07001226 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001227 return 0;
1228}
1229
1230EXPORT_SYMBOL(generic_file_open);
1231
1232/*
1233 * This is used by subsystems that don't want seekable
1234 * file descriptors
1235 */
1236int nonseekable_open(struct inode *inode, struct file *filp)
1237{
1238 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1239 return 0;
1240}
1241
1242EXPORT_SYMBOL(nonseekable_open);