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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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> | |
9 | #include <linux/utime.h> | |
10 | #include <linux/file.h> | |
11 | #include <linux/smp_lock.h> | |
12 | #include <linux/quotaops.h> | |
0eeca283 | 13 | #include <linux/fsnotify.h> |
1da177e4 LT |
14 | #include <linux/module.h> |
15 | #include <linux/slab.h> | |
16 | #include <linux/tty.h> | |
17 | #include <linux/namei.h> | |
18 | #include <linux/backing-dev.h> | |
19 | #include <linux/security.h> | |
20 | #include <linux/mount.h> | |
21 | #include <linux/vfs.h> | |
22 | #include <asm/uaccess.h> | |
23 | #include <linux/fs.h> | |
ef3daeda | 24 | #include <linux/personality.h> |
1da177e4 LT |
25 | #include <linux/pagemap.h> |
26 | #include <linux/syscalls.h> | |
ab2af1f5 | 27 | #include <linux/rcupdate.h> |
1da177e4 LT |
28 | |
29 | #include <asm/unistd.h> | |
30 | ||
31 | int vfs_statfs(struct super_block *sb, struct kstatfs *buf) | |
32 | { | |
33 | int retval = -ENODEV; | |
34 | ||
35 | if (sb) { | |
36 | retval = -ENOSYS; | |
37 | if (sb->s_op->statfs) { | |
38 | memset(buf, 0, sizeof(*buf)); | |
39 | retval = security_sb_statfs(sb); | |
40 | if (retval) | |
41 | return retval; | |
42 | retval = sb->s_op->statfs(sb, buf); | |
43 | if (retval == 0 && buf->f_frsize == 0) | |
44 | buf->f_frsize = buf->f_bsize; | |
45 | } | |
46 | } | |
47 | return retval; | |
48 | } | |
49 | ||
50 | EXPORT_SYMBOL(vfs_statfs); | |
51 | ||
52 | static int vfs_statfs_native(struct super_block *sb, struct statfs *buf) | |
53 | { | |
54 | struct kstatfs st; | |
55 | int retval; | |
56 | ||
57 | retval = vfs_statfs(sb, &st); | |
58 | 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 | ||
95 | static int vfs_statfs64(struct super_block *sb, struct statfs64 *buf) | |
96 | { | |
97 | struct kstatfs st; | |
98 | int retval; | |
99 | ||
100 | retval = vfs_statfs(sb, &st); | |
101 | 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 | ||
122 | asmlinkage 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; | |
130 | error = vfs_statfs_native(nd.dentry->d_inode->i_sb, &tmp); | |
131 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) | |
132 | error = -EFAULT; | |
133 | path_release(&nd); | |
134 | } | |
135 | return error; | |
136 | } | |
137 | ||
138 | ||
139 | asmlinkage 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; | |
149 | error = vfs_statfs64(nd.dentry->d_inode->i_sb, &tmp); | |
150 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) | |
151 | error = -EFAULT; | |
152 | path_release(&nd); | |
153 | } | |
154 | return error; | |
155 | } | |
156 | ||
157 | ||
158 | asmlinkage 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; | |
168 | error = vfs_statfs_native(file->f_dentry->d_inode->i_sb, &tmp); | |
169 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) | |
170 | error = -EFAULT; | |
171 | fput(file); | |
172 | out: | |
173 | return error; | |
174 | } | |
175 | ||
176 | asmlinkage 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; | |
189 | error = vfs_statfs64(file->f_dentry->d_inode->i_sb, &tmp); | |
190 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) | |
191 | error = -EFAULT; | |
192 | fput(file); | |
193 | out: | |
194 | return error; | |
195 | } | |
196 | ||
197 | int do_truncate(struct dentry *dentry, loff_t length) | |
198 | { | |
199 | int err; | |
200 | struct iattr newattrs; | |
201 | ||
202 | /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */ | |
203 | if (length < 0) | |
204 | return -EINVAL; | |
205 | ||
206 | newattrs.ia_size = length; | |
207 | newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; | |
208 | ||
209 | down(&dentry->d_inode->i_sem); | |
210 | err = notify_change(dentry, &newattrs); | |
211 | up(&dentry->d_inode->i_sem); | |
212 | return err; | |
213 | } | |
214 | ||
215 | static inline long do_sys_truncate(const char __user * path, loff_t length) | |
216 | { | |
217 | struct nameidata nd; | |
218 | struct inode * inode; | |
219 | int error; | |
220 | ||
221 | error = -EINVAL; | |
222 | if (length < 0) /* sorry, but loff_t says... */ | |
223 | goto out; | |
224 | ||
225 | error = user_path_walk(path, &nd); | |
226 | if (error) | |
227 | goto out; | |
228 | inode = nd.dentry->d_inode; | |
229 | ||
230 | /* For directories it's -EISDIR, for other non-regulars - -EINVAL */ | |
231 | error = -EISDIR; | |
232 | if (S_ISDIR(inode->i_mode)) | |
233 | goto dput_and_out; | |
234 | ||
235 | error = -EINVAL; | |
236 | if (!S_ISREG(inode->i_mode)) | |
237 | goto dput_and_out; | |
238 | ||
239 | error = permission(inode,MAY_WRITE,&nd); | |
240 | if (error) | |
241 | goto dput_and_out; | |
242 | ||
243 | error = -EROFS; | |
244 | if (IS_RDONLY(inode)) | |
245 | goto dput_and_out; | |
246 | ||
247 | error = -EPERM; | |
248 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) | |
249 | goto dput_and_out; | |
250 | ||
251 | /* | |
252 | * Make sure that there are no leases. | |
253 | */ | |
254 | error = break_lease(inode, FMODE_WRITE); | |
255 | if (error) | |
256 | goto dput_and_out; | |
257 | ||
258 | error = get_write_access(inode); | |
259 | if (error) | |
260 | goto dput_and_out; | |
261 | ||
262 | error = locks_verify_truncate(inode, NULL, length); | |
263 | if (!error) { | |
264 | DQUOT_INIT(inode); | |
265 | error = do_truncate(nd.dentry, length); | |
266 | } | |
267 | put_write_access(inode); | |
268 | ||
269 | dput_and_out: | |
270 | path_release(&nd); | |
271 | out: | |
272 | return error; | |
273 | } | |
274 | ||
275 | asmlinkage long sys_truncate(const char __user * path, unsigned long length) | |
276 | { | |
277 | /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */ | |
278 | return do_sys_truncate(path, (long)length); | |
279 | } | |
280 | ||
281 | static inline long do_sys_ftruncate(unsigned int fd, loff_t length, int small) | |
282 | { | |
283 | struct inode * inode; | |
284 | struct dentry *dentry; | |
285 | struct file * file; | |
286 | int error; | |
287 | ||
288 | error = -EINVAL; | |
289 | if (length < 0) | |
290 | goto out; | |
291 | error = -EBADF; | |
292 | file = fget(fd); | |
293 | if (!file) | |
294 | goto out; | |
295 | ||
296 | /* explicitly opened as large or we are on 64-bit box */ | |
297 | if (file->f_flags & O_LARGEFILE) | |
298 | small = 0; | |
299 | ||
300 | dentry = file->f_dentry; | |
301 | inode = dentry->d_inode; | |
302 | error = -EINVAL; | |
303 | if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) | |
304 | goto out_putf; | |
305 | ||
306 | error = -EINVAL; | |
307 | /* Cannot ftruncate over 2^31 bytes without large file support */ | |
308 | if (small && length > MAX_NON_LFS) | |
309 | goto out_putf; | |
310 | ||
311 | error = -EPERM; | |
312 | if (IS_APPEND(inode)) | |
313 | goto out_putf; | |
314 | ||
315 | error = locks_verify_truncate(inode, file, length); | |
316 | if (!error) | |
317 | error = do_truncate(dentry, length); | |
318 | out_putf: | |
319 | fput(file); | |
320 | out: | |
321 | return error; | |
322 | } | |
323 | ||
324 | asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length) | |
325 | { | |
326 | return do_sys_ftruncate(fd, length, 1); | |
327 | } | |
328 | ||
329 | /* LFS versions of truncate are only needed on 32 bit machines */ | |
330 | #if BITS_PER_LONG == 32 | |
331 | asmlinkage long sys_truncate64(const char __user * path, loff_t length) | |
332 | { | |
333 | return do_sys_truncate(path, length); | |
334 | } | |
335 | ||
336 | asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length) | |
337 | { | |
338 | return do_sys_ftruncate(fd, length, 0); | |
339 | } | |
340 | #endif | |
341 | ||
342 | #ifdef __ARCH_WANT_SYS_UTIME | |
343 | ||
344 | /* | |
345 | * sys_utime() can be implemented in user-level using sys_utimes(). | |
346 | * Is this for backwards compatibility? If so, why not move it | |
347 | * into the appropriate arch directory (for those architectures that | |
348 | * need it). | |
349 | */ | |
350 | ||
351 | /* If times==NULL, set access and modification to current time, | |
352 | * must be owner or have write permission. | |
353 | * Else, update from *times, must be owner or super user. | |
354 | */ | |
355 | asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times) | |
356 | { | |
357 | int error; | |
358 | struct nameidata nd; | |
359 | struct inode * inode; | |
360 | struct iattr newattrs; | |
361 | ||
362 | error = user_path_walk(filename, &nd); | |
363 | if (error) | |
364 | goto out; | |
365 | inode = nd.dentry->d_inode; | |
366 | ||
367 | error = -EROFS; | |
368 | if (IS_RDONLY(inode)) | |
369 | goto dput_and_out; | |
370 | ||
371 | /* Don't worry, the checks are done in inode_change_ok() */ | |
372 | newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME; | |
373 | if (times) { | |
374 | error = -EPERM; | |
375 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) | |
376 | goto dput_and_out; | |
377 | ||
378 | error = get_user(newattrs.ia_atime.tv_sec, ×->actime); | |
379 | newattrs.ia_atime.tv_nsec = 0; | |
380 | if (!error) | |
381 | error = get_user(newattrs.ia_mtime.tv_sec, ×->modtime); | |
382 | newattrs.ia_mtime.tv_nsec = 0; | |
383 | if (error) | |
384 | goto dput_and_out; | |
385 | ||
386 | newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET; | |
387 | } else { | |
388 | error = -EACCES; | |
389 | if (IS_IMMUTABLE(inode)) | |
390 | goto dput_and_out; | |
391 | ||
392 | if (current->fsuid != inode->i_uid && | |
393 | (error = permission(inode,MAY_WRITE,&nd)) != 0) | |
394 | goto dput_and_out; | |
395 | } | |
396 | down(&inode->i_sem); | |
397 | error = notify_change(nd.dentry, &newattrs); | |
398 | up(&inode->i_sem); | |
399 | dput_and_out: | |
400 | path_release(&nd); | |
401 | out: | |
402 | return error; | |
403 | } | |
404 | ||
405 | #endif | |
406 | ||
407 | /* If times==NULL, set access and modification to current time, | |
408 | * must be owner or have write permission. | |
409 | * Else, update from *times, must be owner or super user. | |
410 | */ | |
411 | long do_utimes(char __user * filename, struct timeval * times) | |
412 | { | |
413 | int error; | |
414 | struct nameidata nd; | |
415 | struct inode * inode; | |
416 | struct iattr newattrs; | |
417 | ||
418 | error = user_path_walk(filename, &nd); | |
419 | ||
420 | if (error) | |
421 | goto out; | |
422 | inode = nd.dentry->d_inode; | |
423 | ||
424 | error = -EROFS; | |
425 | if (IS_RDONLY(inode)) | |
426 | goto dput_and_out; | |
427 | ||
428 | /* Don't worry, the checks are done in inode_change_ok() */ | |
429 | newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME; | |
430 | if (times) { | |
431 | error = -EPERM; | |
432 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) | |
433 | goto dput_and_out; | |
434 | ||
435 | newattrs.ia_atime.tv_sec = times[0].tv_sec; | |
436 | newattrs.ia_atime.tv_nsec = times[0].tv_usec * 1000; | |
437 | newattrs.ia_mtime.tv_sec = times[1].tv_sec; | |
438 | newattrs.ia_mtime.tv_nsec = times[1].tv_usec * 1000; | |
439 | newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET; | |
440 | } else { | |
441 | error = -EACCES; | |
442 | if (IS_IMMUTABLE(inode)) | |
443 | goto dput_and_out; | |
444 | ||
445 | if (current->fsuid != inode->i_uid && | |
446 | (error = permission(inode,MAY_WRITE,&nd)) != 0) | |
447 | goto dput_and_out; | |
448 | } | |
449 | down(&inode->i_sem); | |
450 | error = notify_change(nd.dentry, &newattrs); | |
451 | up(&inode->i_sem); | |
452 | dput_and_out: | |
453 | path_release(&nd); | |
454 | out: | |
455 | return error; | |
456 | } | |
457 | ||
458 | asmlinkage long sys_utimes(char __user * filename, struct timeval __user * utimes) | |
459 | { | |
460 | struct timeval times[2]; | |
461 | ||
462 | if (utimes && copy_from_user(×, utimes, sizeof(times))) | |
463 | return -EFAULT; | |
464 | return do_utimes(filename, utimes ? times : NULL); | |
465 | } | |
466 | ||
467 | ||
468 | /* | |
469 | * access() needs to use the real uid/gid, not the effective uid/gid. | |
470 | * We do this by temporarily clearing all FS-related capabilities and | |
471 | * switching the fsuid/fsgid around to the real ones. | |
472 | */ | |
473 | asmlinkage long sys_access(const char __user * filename, int mode) | |
474 | { | |
475 | struct nameidata nd; | |
476 | int old_fsuid, old_fsgid; | |
477 | kernel_cap_t old_cap; | |
478 | int res; | |
479 | ||
480 | if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */ | |
481 | return -EINVAL; | |
482 | ||
483 | old_fsuid = current->fsuid; | |
484 | old_fsgid = current->fsgid; | |
485 | old_cap = current->cap_effective; | |
486 | ||
487 | current->fsuid = current->uid; | |
488 | current->fsgid = current->gid; | |
489 | ||
490 | /* | |
491 | * Clear the capabilities if we switch to a non-root user | |
492 | * | |
493 | * FIXME: There is a race here against sys_capset. The | |
494 | * capabilities can change yet we will restore the old | |
495 | * value below. We should hold task_capabilities_lock, | |
496 | * but we cannot because user_path_walk can sleep. | |
497 | */ | |
498 | if (current->uid) | |
499 | cap_clear(current->cap_effective); | |
500 | else | |
501 | current->cap_effective = current->cap_permitted; | |
502 | ||
503 | res = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd); | |
504 | if (!res) { | |
505 | res = permission(nd.dentry->d_inode, mode, &nd); | |
506 | /* SuS v2 requires we report a read only fs too */ | |
507 | if(!res && (mode & S_IWOTH) && IS_RDONLY(nd.dentry->d_inode) | |
508 | && !special_file(nd.dentry->d_inode->i_mode)) | |
509 | res = -EROFS; | |
510 | path_release(&nd); | |
511 | } | |
512 | ||
513 | current->fsuid = old_fsuid; | |
514 | current->fsgid = old_fsgid; | |
515 | current->cap_effective = old_cap; | |
516 | ||
517 | return res; | |
518 | } | |
519 | ||
520 | asmlinkage long sys_chdir(const char __user * filename) | |
521 | { | |
522 | struct nameidata nd; | |
523 | int error; | |
524 | ||
525 | error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd); | |
526 | if (error) | |
527 | goto out; | |
528 | ||
529 | error = permission(nd.dentry->d_inode,MAY_EXEC,&nd); | |
530 | if (error) | |
531 | goto dput_and_out; | |
532 | ||
533 | set_fs_pwd(current->fs, nd.mnt, nd.dentry); | |
534 | ||
535 | dput_and_out: | |
536 | path_release(&nd); | |
537 | out: | |
538 | return error; | |
539 | } | |
540 | ||
541 | asmlinkage long sys_fchdir(unsigned int fd) | |
542 | { | |
543 | struct file *file; | |
544 | struct dentry *dentry; | |
545 | struct inode *inode; | |
546 | struct vfsmount *mnt; | |
547 | int error; | |
548 | ||
549 | error = -EBADF; | |
550 | file = fget(fd); | |
551 | if (!file) | |
552 | goto out; | |
553 | ||
554 | dentry = file->f_dentry; | |
555 | mnt = file->f_vfsmnt; | |
556 | inode = dentry->d_inode; | |
557 | ||
558 | error = -ENOTDIR; | |
559 | if (!S_ISDIR(inode->i_mode)) | |
560 | goto out_putf; | |
561 | ||
562 | error = permission(inode, MAY_EXEC, NULL); | |
563 | if (!error) | |
564 | set_fs_pwd(current->fs, mnt, dentry); | |
565 | out_putf: | |
566 | fput(file); | |
567 | out: | |
568 | return error; | |
569 | } | |
570 | ||
571 | asmlinkage long sys_chroot(const char __user * filename) | |
572 | { | |
573 | struct nameidata nd; | |
574 | int error; | |
575 | ||
576 | error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd); | |
577 | if (error) | |
578 | goto out; | |
579 | ||
580 | error = permission(nd.dentry->d_inode,MAY_EXEC,&nd); | |
581 | if (error) | |
582 | goto dput_and_out; | |
583 | ||
584 | error = -EPERM; | |
585 | if (!capable(CAP_SYS_CHROOT)) | |
586 | goto dput_and_out; | |
587 | ||
588 | set_fs_root(current->fs, nd.mnt, nd.dentry); | |
589 | set_fs_altroot(); | |
590 | error = 0; | |
591 | dput_and_out: | |
592 | path_release(&nd); | |
593 | out: | |
594 | return error; | |
595 | } | |
596 | ||
597 | asmlinkage long sys_fchmod(unsigned int fd, mode_t mode) | |
598 | { | |
599 | struct inode * inode; | |
600 | struct dentry * dentry; | |
601 | struct file * file; | |
602 | int err = -EBADF; | |
603 | struct iattr newattrs; | |
604 | ||
605 | file = fget(fd); | |
606 | if (!file) | |
607 | goto out; | |
608 | ||
609 | dentry = file->f_dentry; | |
610 | inode = dentry->d_inode; | |
611 | ||
612 | err = -EROFS; | |
613 | if (IS_RDONLY(inode)) | |
614 | goto out_putf; | |
615 | err = -EPERM; | |
616 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) | |
617 | goto out_putf; | |
618 | down(&inode->i_sem); | |
619 | if (mode == (mode_t) -1) | |
620 | mode = inode->i_mode; | |
621 | newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); | |
622 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; | |
623 | err = notify_change(dentry, &newattrs); | |
624 | up(&inode->i_sem); | |
625 | ||
626 | out_putf: | |
627 | fput(file); | |
628 | out: | |
629 | return err; | |
630 | } | |
631 | ||
632 | asmlinkage long sys_chmod(const char __user * filename, mode_t mode) | |
633 | { | |
634 | struct nameidata nd; | |
635 | struct inode * inode; | |
636 | int error; | |
637 | struct iattr newattrs; | |
638 | ||
639 | error = user_path_walk(filename, &nd); | |
640 | if (error) | |
641 | goto out; | |
642 | inode = nd.dentry->d_inode; | |
643 | ||
644 | error = -EROFS; | |
645 | if (IS_RDONLY(inode)) | |
646 | goto dput_and_out; | |
647 | ||
648 | error = -EPERM; | |
649 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) | |
650 | goto dput_and_out; | |
651 | ||
652 | down(&inode->i_sem); | |
653 | if (mode == (mode_t) -1) | |
654 | mode = inode->i_mode; | |
655 | newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); | |
656 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; | |
657 | error = notify_change(nd.dentry, &newattrs); | |
658 | up(&inode->i_sem); | |
659 | ||
660 | dput_and_out: | |
661 | path_release(&nd); | |
662 | out: | |
663 | return error; | |
664 | } | |
665 | ||
666 | static int chown_common(struct dentry * dentry, uid_t user, gid_t group) | |
667 | { | |
668 | struct inode * inode; | |
669 | int error; | |
670 | struct iattr newattrs; | |
671 | ||
672 | error = -ENOENT; | |
673 | if (!(inode = dentry->d_inode)) { | |
674 | printk(KERN_ERR "chown_common: NULL inode\n"); | |
675 | goto out; | |
676 | } | |
677 | error = -EROFS; | |
678 | if (IS_RDONLY(inode)) | |
679 | goto out; | |
680 | error = -EPERM; | |
681 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) | |
682 | goto out; | |
683 | newattrs.ia_valid = ATTR_CTIME; | |
684 | if (user != (uid_t) -1) { | |
685 | newattrs.ia_valid |= ATTR_UID; | |
686 | newattrs.ia_uid = user; | |
687 | } | |
688 | if (group != (gid_t) -1) { | |
689 | newattrs.ia_valid |= ATTR_GID; | |
690 | newattrs.ia_gid = group; | |
691 | } | |
692 | if (!S_ISDIR(inode->i_mode)) | |
693 | newattrs.ia_valid |= ATTR_KILL_SUID|ATTR_KILL_SGID; | |
694 | down(&inode->i_sem); | |
695 | error = notify_change(dentry, &newattrs); | |
696 | up(&inode->i_sem); | |
697 | out: | |
698 | return error; | |
699 | } | |
700 | ||
701 | asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group) | |
702 | { | |
703 | struct nameidata nd; | |
704 | int error; | |
705 | ||
706 | error = user_path_walk(filename, &nd); | |
707 | if (!error) { | |
708 | error = chown_common(nd.dentry, user, group); | |
709 | path_release(&nd); | |
710 | } | |
711 | return error; | |
712 | } | |
713 | ||
714 | asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group) | |
715 | { | |
716 | struct nameidata nd; | |
717 | int error; | |
718 | ||
719 | error = user_path_walk_link(filename, &nd); | |
720 | if (!error) { | |
721 | error = chown_common(nd.dentry, user, group); | |
722 | path_release(&nd); | |
723 | } | |
724 | return error; | |
725 | } | |
726 | ||
727 | ||
728 | asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group) | |
729 | { | |
730 | struct file * file; | |
731 | int error = -EBADF; | |
732 | ||
733 | file = fget(fd); | |
734 | if (file) { | |
735 | error = chown_common(file->f_dentry, user, group); | |
736 | fput(file); | |
737 | } | |
738 | return error; | |
739 | } | |
740 | ||
741 | /* | |
742 | * Note that while the flag value (low two bits) for sys_open means: | |
743 | * 00 - read-only | |
744 | * 01 - write-only | |
745 | * 10 - read-write | |
746 | * 11 - special | |
747 | * it is changed into | |
748 | * 00 - no permissions needed | |
749 | * 01 - read-permission | |
750 | * 10 - write-permission | |
751 | * 11 - read-write | |
752 | * for the internal routines (ie open_namei()/follow_link() etc). 00 is | |
753 | * used by symlinks. | |
754 | */ | |
755 | struct file *filp_open(const char * filename, int flags, int mode) | |
756 | { | |
757 | int namei_flags, error; | |
758 | struct nameidata nd; | |
759 | ||
760 | namei_flags = flags; | |
761 | if ((namei_flags+1) & O_ACCMODE) | |
762 | namei_flags++; | |
763 | if (namei_flags & O_TRUNC) | |
764 | namei_flags |= 2; | |
765 | ||
766 | error = open_namei(filename, namei_flags, mode, &nd); | |
767 | if (!error) | |
768 | return dentry_open(nd.dentry, nd.mnt, flags); | |
769 | ||
770 | return ERR_PTR(error); | |
771 | } | |
772 | ||
773 | EXPORT_SYMBOL(filp_open); | |
774 | ||
775 | struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags) | |
776 | { | |
777 | struct file * f; | |
778 | struct inode *inode; | |
779 | int error; | |
780 | ||
781 | error = -ENFILE; | |
782 | f = get_empty_filp(); | |
783 | if (!f) | |
784 | goto cleanup_dentry; | |
785 | f->f_flags = flags; | |
786 | f->f_mode = ((flags+1) & O_ACCMODE) | FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; | |
787 | inode = dentry->d_inode; | |
788 | if (f->f_mode & FMODE_WRITE) { | |
789 | error = get_write_access(inode); | |
790 | if (error) | |
791 | goto cleanup_file; | |
792 | } | |
793 | ||
794 | f->f_mapping = inode->i_mapping; | |
795 | f->f_dentry = dentry; | |
796 | f->f_vfsmnt = mnt; | |
797 | f->f_pos = 0; | |
798 | f->f_op = fops_get(inode->i_fop); | |
799 | file_move(f, &inode->i_sb->s_files); | |
800 | ||
801 | if (f->f_op && f->f_op->open) { | |
802 | error = f->f_op->open(inode,f); | |
803 | if (error) | |
804 | goto cleanup_all; | |
805 | } | |
806 | f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); | |
807 | ||
808 | file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping); | |
809 | ||
810 | /* NB: we're sure to have correct a_ops only after f_op->open */ | |
811 | if (f->f_flags & O_DIRECT) { | |
ceffc078 CO |
812 | if (!f->f_mapping->a_ops || |
813 | ((!f->f_mapping->a_ops->direct_IO) && | |
814 | (!f->f_mapping->a_ops->get_xip_page))) { | |
1da177e4 LT |
815 | fput(f); |
816 | f = ERR_PTR(-EINVAL); | |
817 | } | |
818 | } | |
819 | ||
820 | return f; | |
821 | ||
822 | cleanup_all: | |
823 | fops_put(f->f_op); | |
824 | if (f->f_mode & FMODE_WRITE) | |
825 | put_write_access(inode); | |
826 | file_kill(f); | |
827 | f->f_dentry = NULL; | |
828 | f->f_vfsmnt = NULL; | |
829 | cleanup_file: | |
830 | put_filp(f); | |
831 | cleanup_dentry: | |
832 | dput(dentry); | |
833 | mntput(mnt); | |
834 | return ERR_PTR(error); | |
835 | } | |
836 | ||
837 | EXPORT_SYMBOL(dentry_open); | |
838 | ||
839 | /* | |
840 | * Find an empty file descriptor entry, and mark it busy. | |
841 | */ | |
842 | int get_unused_fd(void) | |
843 | { | |
844 | struct files_struct * files = current->files; | |
845 | int fd, error; | |
badf1662 | 846 | struct fdtable *fdt; |
1da177e4 LT |
847 | |
848 | error = -EMFILE; | |
849 | spin_lock(&files->file_lock); | |
850 | ||
851 | repeat: | |
badf1662 DS |
852 | fdt = files_fdtable(files); |
853 | fd = find_next_zero_bit(fdt->open_fds->fds_bits, | |
854 | fdt->max_fdset, | |
855 | fdt->next_fd); | |
1da177e4 LT |
856 | |
857 | /* | |
858 | * N.B. For clone tasks sharing a files structure, this test | |
859 | * will limit the total number of files that can be opened. | |
860 | */ | |
861 | if (fd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) | |
862 | goto out; | |
863 | ||
864 | /* Do we need to expand the fd array or fd set? */ | |
865 | error = expand_files(files, fd); | |
866 | if (error < 0) | |
867 | goto out; | |
868 | ||
869 | if (error) { | |
870 | /* | |
871 | * If we needed to expand the fs array we | |
872 | * might have blocked - try again. | |
873 | */ | |
874 | error = -EMFILE; | |
875 | goto repeat; | |
876 | } | |
877 | ||
badf1662 DS |
878 | FD_SET(fd, fdt->open_fds); |
879 | FD_CLR(fd, fdt->close_on_exec); | |
880 | fdt->next_fd = fd + 1; | |
1da177e4 LT |
881 | #if 1 |
882 | /* Sanity check */ | |
badf1662 | 883 | if (fdt->fd[fd] != NULL) { |
1da177e4 | 884 | printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd); |
badf1662 | 885 | fdt->fd[fd] = NULL; |
1da177e4 LT |
886 | } |
887 | #endif | |
888 | error = fd; | |
889 | ||
890 | out: | |
891 | spin_unlock(&files->file_lock); | |
892 | return error; | |
893 | } | |
894 | ||
895 | EXPORT_SYMBOL(get_unused_fd); | |
896 | ||
897 | static inline void __put_unused_fd(struct files_struct *files, unsigned int fd) | |
898 | { | |
badf1662 DS |
899 | struct fdtable *fdt = files_fdtable(files); |
900 | __FD_CLR(fd, fdt->open_fds); | |
901 | if (fd < fdt->next_fd) | |
902 | fdt->next_fd = fd; | |
1da177e4 LT |
903 | } |
904 | ||
905 | void fastcall put_unused_fd(unsigned int fd) | |
906 | { | |
907 | struct files_struct *files = current->files; | |
908 | spin_lock(&files->file_lock); | |
909 | __put_unused_fd(files, fd); | |
910 | spin_unlock(&files->file_lock); | |
911 | } | |
912 | ||
913 | EXPORT_SYMBOL(put_unused_fd); | |
914 | ||
915 | /* | |
916 | * Install a file pointer in the fd array. | |
917 | * | |
918 | * The VFS is full of places where we drop the files lock between | |
919 | * setting the open_fds bitmap and installing the file in the file | |
920 | * array. At any such point, we are vulnerable to a dup2() race | |
921 | * installing a file in the array before us. We need to detect this and | |
922 | * fput() the struct file we are about to overwrite in this case. | |
923 | * | |
924 | * It should never happen - if we allow dup2() do it, _really_ bad things | |
925 | * will follow. | |
926 | */ | |
927 | ||
928 | void fastcall fd_install(unsigned int fd, struct file * file) | |
929 | { | |
930 | struct files_struct *files = current->files; | |
badf1662 | 931 | struct fdtable *fdt; |
1da177e4 | 932 | spin_lock(&files->file_lock); |
badf1662 | 933 | fdt = files_fdtable(files); |
ab2af1f5 DS |
934 | BUG_ON(fdt->fd[fd] != NULL); |
935 | rcu_assign_pointer(fdt->fd[fd], file); | |
1da177e4 LT |
936 | spin_unlock(&files->file_lock); |
937 | } | |
938 | ||
939 | EXPORT_SYMBOL(fd_install); | |
940 | ||
e922efc3 | 941 | long do_sys_open(const char __user *filename, int flags, int mode) |
1da177e4 | 942 | { |
e922efc3 MS |
943 | char *tmp = getname(filename); |
944 | int fd = PTR_ERR(tmp); | |
1da177e4 | 945 | |
1da177e4 LT |
946 | if (!IS_ERR(tmp)) { |
947 | fd = get_unused_fd(); | |
948 | if (fd >= 0) { | |
949 | struct file *f = filp_open(tmp, flags, mode); | |
fed2fc18 TN |
950 | if (IS_ERR(f)) { |
951 | put_unused_fd(fd); | |
952 | fd = PTR_ERR(f); | |
953 | } else { | |
0eeca283 | 954 | fsnotify_open(f->f_dentry); |
fed2fc18 TN |
955 | fd_install(fd, f); |
956 | } | |
1da177e4 | 957 | } |
1da177e4 LT |
958 | putname(tmp); |
959 | } | |
960 | return fd; | |
1da177e4 | 961 | } |
e922efc3 MS |
962 | |
963 | asmlinkage long sys_open(const char __user *filename, int flags, int mode) | |
964 | { | |
965 | if (force_o_largefile()) | |
966 | flags |= O_LARGEFILE; | |
967 | ||
968 | return do_sys_open(filename, flags, mode); | |
969 | } | |
1da177e4 LT |
970 | EXPORT_SYMBOL_GPL(sys_open); |
971 | ||
972 | #ifndef __alpha__ | |
973 | ||
974 | /* | |
975 | * For backward compatibility? Maybe this should be moved | |
976 | * into arch/i386 instead? | |
977 | */ | |
978 | asmlinkage long sys_creat(const char __user * pathname, int mode) | |
979 | { | |
980 | return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode); | |
981 | } | |
982 | ||
983 | #endif | |
984 | ||
985 | /* | |
986 | * "id" is the POSIX thread ID. We use the | |
987 | * files pointer for this.. | |
988 | */ | |
989 | int filp_close(struct file *filp, fl_owner_t id) | |
990 | { | |
45778ca8 | 991 | int retval = 0; |
1da177e4 LT |
992 | |
993 | if (!file_count(filp)) { | |
994 | printk(KERN_ERR "VFS: Close: file count is 0\n"); | |
45778ca8 | 995 | return 0; |
1da177e4 LT |
996 | } |
997 | ||
45778ca8 CL |
998 | if (filp->f_op && filp->f_op->flush) |
999 | retval = filp->f_op->flush(filp); | |
1da177e4 LT |
1000 | |
1001 | dnotify_flush(filp, id); | |
1002 | locks_remove_posix(filp, id); | |
1003 | fput(filp); | |
1004 | return retval; | |
1005 | } | |
1006 | ||
1007 | EXPORT_SYMBOL(filp_close); | |
1008 | ||
1009 | /* | |
1010 | * Careful here! We test whether the file pointer is NULL before | |
1011 | * releasing the fd. This ensures that one clone task can't release | |
1012 | * an fd while another clone is opening it. | |
1013 | */ | |
1014 | asmlinkage long sys_close(unsigned int fd) | |
1015 | { | |
1016 | struct file * filp; | |
1017 | struct files_struct *files = current->files; | |
badf1662 | 1018 | struct fdtable *fdt; |
1da177e4 LT |
1019 | |
1020 | spin_lock(&files->file_lock); | |
badf1662 DS |
1021 | fdt = files_fdtable(files); |
1022 | if (fd >= fdt->max_fds) | |
1da177e4 | 1023 | goto out_unlock; |
badf1662 | 1024 | filp = fdt->fd[fd]; |
1da177e4 LT |
1025 | if (!filp) |
1026 | goto out_unlock; | |
ab2af1f5 | 1027 | rcu_assign_pointer(fdt->fd[fd], NULL); |
badf1662 | 1028 | FD_CLR(fd, fdt->close_on_exec); |
1da177e4 LT |
1029 | __put_unused_fd(files, fd); |
1030 | spin_unlock(&files->file_lock); | |
1031 | return filp_close(filp, files); | |
1032 | ||
1033 | out_unlock: | |
1034 | spin_unlock(&files->file_lock); | |
1035 | return -EBADF; | |
1036 | } | |
1037 | ||
1038 | EXPORT_SYMBOL(sys_close); | |
1039 | ||
1040 | /* | |
1041 | * This routine simulates a hangup on the tty, to arrange that users | |
1042 | * are given clean terminals at login time. | |
1043 | */ | |
1044 | asmlinkage long sys_vhangup(void) | |
1045 | { | |
1046 | if (capable(CAP_SYS_TTY_CONFIG)) { | |
1047 | tty_vhangup(current->signal->tty); | |
1048 | return 0; | |
1049 | } | |
1050 | return -EPERM; | |
1051 | } | |
1052 | ||
1053 | /* | |
1054 | * Called when an inode is about to be open. | |
1055 | * We use this to disallow opening large files on 32bit systems if | |
1056 | * the caller didn't specify O_LARGEFILE. On 64bit systems we force | |
1057 | * on this flag in sys_open. | |
1058 | */ | |
1059 | int generic_file_open(struct inode * inode, struct file * filp) | |
1060 | { | |
1061 | if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS) | |
1062 | return -EFBIG; | |
1063 | return 0; | |
1064 | } | |
1065 | ||
1066 | EXPORT_SYMBOL(generic_file_open); | |
1067 | ||
1068 | /* | |
1069 | * This is used by subsystems that don't want seekable | |
1070 | * file descriptors | |
1071 | */ | |
1072 | int nonseekable_open(struct inode *inode, struct file *filp) | |
1073 | { | |
1074 | filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); | |
1075 | return 0; | |
1076 | } | |
1077 | ||
1078 | EXPORT_SYMBOL(nonseekable_open); |