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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> | |
13 | #include <linux/dnotify.h> | |
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> | |
24 | #include <linux/pagemap.h> | |
25 | #include <linux/syscalls.h> | |
26 | ||
27 | #include <asm/unistd.h> | |
28 | ||
29 | int vfs_statfs(struct super_block *sb, struct kstatfs *buf) | |
30 | { | |
31 | int retval = -ENODEV; | |
32 | ||
33 | if (sb) { | |
34 | retval = -ENOSYS; | |
35 | if (sb->s_op->statfs) { | |
36 | memset(buf, 0, sizeof(*buf)); | |
37 | retval = security_sb_statfs(sb); | |
38 | if (retval) | |
39 | return retval; | |
40 | retval = sb->s_op->statfs(sb, buf); | |
41 | if (retval == 0 && buf->f_frsize == 0) | |
42 | buf->f_frsize = buf->f_bsize; | |
43 | } | |
44 | } | |
45 | return retval; | |
46 | } | |
47 | ||
48 | EXPORT_SYMBOL(vfs_statfs); | |
49 | ||
50 | static int vfs_statfs_native(struct super_block *sb, struct statfs *buf) | |
51 | { | |
52 | struct kstatfs st; | |
53 | int retval; | |
54 | ||
55 | retval = vfs_statfs(sb, &st); | |
56 | if (retval) | |
57 | return retval; | |
58 | ||
59 | if (sizeof(*buf) == sizeof(st)) | |
60 | memcpy(buf, &st, sizeof(st)); | |
61 | else { | |
62 | if (sizeof buf->f_blocks == 4) { | |
63 | if ((st.f_blocks | st.f_bfree | st.f_bavail) & | |
64 | 0xffffffff00000000ULL) | |
65 | return -EOVERFLOW; | |
66 | /* | |
67 | * f_files and f_ffree may be -1; it's okay to stuff | |
68 | * that into 32 bits | |
69 | */ | |
70 | if (st.f_files != -1 && | |
71 | (st.f_files & 0xffffffff00000000ULL)) | |
72 | return -EOVERFLOW; | |
73 | if (st.f_ffree != -1 && | |
74 | (st.f_ffree & 0xffffffff00000000ULL)) | |
75 | return -EOVERFLOW; | |
76 | } | |
77 | ||
78 | buf->f_type = st.f_type; | |
79 | buf->f_bsize = st.f_bsize; | |
80 | buf->f_blocks = st.f_blocks; | |
81 | buf->f_bfree = st.f_bfree; | |
82 | buf->f_bavail = st.f_bavail; | |
83 | buf->f_files = st.f_files; | |
84 | buf->f_ffree = st.f_ffree; | |
85 | buf->f_fsid = st.f_fsid; | |
86 | buf->f_namelen = st.f_namelen; | |
87 | buf->f_frsize = st.f_frsize; | |
88 | memset(buf->f_spare, 0, sizeof(buf->f_spare)); | |
89 | } | |
90 | return 0; | |
91 | } | |
92 | ||
93 | static int vfs_statfs64(struct super_block *sb, struct statfs64 *buf) | |
94 | { | |
95 | struct kstatfs st; | |
96 | int retval; | |
97 | ||
98 | retval = vfs_statfs(sb, &st); | |
99 | if (retval) | |
100 | return retval; | |
101 | ||
102 | if (sizeof(*buf) == sizeof(st)) | |
103 | memcpy(buf, &st, sizeof(st)); | |
104 | else { | |
105 | buf->f_type = st.f_type; | |
106 | buf->f_bsize = st.f_bsize; | |
107 | buf->f_blocks = st.f_blocks; | |
108 | buf->f_bfree = st.f_bfree; | |
109 | buf->f_bavail = st.f_bavail; | |
110 | buf->f_files = st.f_files; | |
111 | buf->f_ffree = st.f_ffree; | |
112 | buf->f_fsid = st.f_fsid; | |
113 | buf->f_namelen = st.f_namelen; | |
114 | buf->f_frsize = st.f_frsize; | |
115 | memset(buf->f_spare, 0, sizeof(buf->f_spare)); | |
116 | } | |
117 | return 0; | |
118 | } | |
119 | ||
120 | asmlinkage long sys_statfs(const char __user * path, struct statfs __user * buf) | |
121 | { | |
122 | struct nameidata nd; | |
123 | int error; | |
124 | ||
125 | error = user_path_walk(path, &nd); | |
126 | if (!error) { | |
127 | struct statfs tmp; | |
128 | error = vfs_statfs_native(nd.dentry->d_inode->i_sb, &tmp); | |
129 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) | |
130 | error = -EFAULT; | |
131 | path_release(&nd); | |
132 | } | |
133 | return error; | |
134 | } | |
135 | ||
136 | ||
137 | asmlinkage long sys_statfs64(const char __user *path, size_t sz, struct statfs64 __user *buf) | |
138 | { | |
139 | struct nameidata nd; | |
140 | long error; | |
141 | ||
142 | if (sz != sizeof(*buf)) | |
143 | return -EINVAL; | |
144 | error = user_path_walk(path, &nd); | |
145 | if (!error) { | |
146 | struct statfs64 tmp; | |
147 | error = vfs_statfs64(nd.dentry->d_inode->i_sb, &tmp); | |
148 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) | |
149 | error = -EFAULT; | |
150 | path_release(&nd); | |
151 | } | |
152 | return error; | |
153 | } | |
154 | ||
155 | ||
156 | asmlinkage long sys_fstatfs(unsigned int fd, struct statfs __user * buf) | |
157 | { | |
158 | struct file * file; | |
159 | struct statfs tmp; | |
160 | int error; | |
161 | ||
162 | error = -EBADF; | |
163 | file = fget(fd); | |
164 | if (!file) | |
165 | goto out; | |
166 | error = vfs_statfs_native(file->f_dentry->d_inode->i_sb, &tmp); | |
167 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) | |
168 | error = -EFAULT; | |
169 | fput(file); | |
170 | out: | |
171 | return error; | |
172 | } | |
173 | ||
174 | asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz, struct statfs64 __user *buf) | |
175 | { | |
176 | struct file * file; | |
177 | struct statfs64 tmp; | |
178 | int error; | |
179 | ||
180 | if (sz != sizeof(*buf)) | |
181 | return -EINVAL; | |
182 | ||
183 | error = -EBADF; | |
184 | file = fget(fd); | |
185 | if (!file) | |
186 | goto out; | |
187 | error = vfs_statfs64(file->f_dentry->d_inode->i_sb, &tmp); | |
188 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) | |
189 | error = -EFAULT; | |
190 | fput(file); | |
191 | out: | |
192 | return error; | |
193 | } | |
194 | ||
195 | int do_truncate(struct dentry *dentry, loff_t length) | |
196 | { | |
197 | int err; | |
198 | struct iattr newattrs; | |
199 | ||
200 | /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */ | |
201 | if (length < 0) | |
202 | return -EINVAL; | |
203 | ||
204 | newattrs.ia_size = length; | |
205 | newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; | |
206 | ||
207 | down(&dentry->d_inode->i_sem); | |
208 | err = notify_change(dentry, &newattrs); | |
209 | up(&dentry->d_inode->i_sem); | |
210 | return err; | |
211 | } | |
212 | ||
213 | static inline long do_sys_truncate(const char __user * path, loff_t length) | |
214 | { | |
215 | struct nameidata nd; | |
216 | struct inode * inode; | |
217 | int error; | |
218 | ||
219 | error = -EINVAL; | |
220 | if (length < 0) /* sorry, but loff_t says... */ | |
221 | goto out; | |
222 | ||
223 | error = user_path_walk(path, &nd); | |
224 | if (error) | |
225 | goto out; | |
226 | inode = nd.dentry->d_inode; | |
227 | ||
228 | /* For directories it's -EISDIR, for other non-regulars - -EINVAL */ | |
229 | error = -EISDIR; | |
230 | if (S_ISDIR(inode->i_mode)) | |
231 | goto dput_and_out; | |
232 | ||
233 | error = -EINVAL; | |
234 | if (!S_ISREG(inode->i_mode)) | |
235 | goto dput_and_out; | |
236 | ||
237 | error = permission(inode,MAY_WRITE,&nd); | |
238 | if (error) | |
239 | goto dput_and_out; | |
240 | ||
241 | error = -EROFS; | |
242 | if (IS_RDONLY(inode)) | |
243 | goto dput_and_out; | |
244 | ||
245 | error = -EPERM; | |
246 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) | |
247 | goto dput_and_out; | |
248 | ||
249 | /* | |
250 | * Make sure that there are no leases. | |
251 | */ | |
252 | error = break_lease(inode, FMODE_WRITE); | |
253 | if (error) | |
254 | goto dput_and_out; | |
255 | ||
256 | error = get_write_access(inode); | |
257 | if (error) | |
258 | goto dput_and_out; | |
259 | ||
260 | error = locks_verify_truncate(inode, NULL, length); | |
261 | if (!error) { | |
262 | DQUOT_INIT(inode); | |
263 | error = do_truncate(nd.dentry, length); | |
264 | } | |
265 | put_write_access(inode); | |
266 | ||
267 | dput_and_out: | |
268 | path_release(&nd); | |
269 | out: | |
270 | return error; | |
271 | } | |
272 | ||
273 | asmlinkage long sys_truncate(const char __user * path, unsigned long length) | |
274 | { | |
275 | /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */ | |
276 | return do_sys_truncate(path, (long)length); | |
277 | } | |
278 | ||
279 | static inline long do_sys_ftruncate(unsigned int fd, loff_t length, int small) | |
280 | { | |
281 | struct inode * inode; | |
282 | struct dentry *dentry; | |
283 | struct file * file; | |
284 | int error; | |
285 | ||
286 | error = -EINVAL; | |
287 | if (length < 0) | |
288 | goto out; | |
289 | error = -EBADF; | |
290 | file = fget(fd); | |
291 | if (!file) | |
292 | goto out; | |
293 | ||
294 | /* explicitly opened as large or we are on 64-bit box */ | |
295 | if (file->f_flags & O_LARGEFILE) | |
296 | small = 0; | |
297 | ||
298 | dentry = file->f_dentry; | |
299 | inode = dentry->d_inode; | |
300 | error = -EINVAL; | |
301 | if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) | |
302 | goto out_putf; | |
303 | ||
304 | error = -EINVAL; | |
305 | /* Cannot ftruncate over 2^31 bytes without large file support */ | |
306 | if (small && length > MAX_NON_LFS) | |
307 | goto out_putf; | |
308 | ||
309 | error = -EPERM; | |
310 | if (IS_APPEND(inode)) | |
311 | goto out_putf; | |
312 | ||
313 | error = locks_verify_truncate(inode, file, length); | |
314 | if (!error) | |
315 | error = do_truncate(dentry, length); | |
316 | out_putf: | |
317 | fput(file); | |
318 | out: | |
319 | return error; | |
320 | } | |
321 | ||
322 | asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length) | |
323 | { | |
324 | return do_sys_ftruncate(fd, length, 1); | |
325 | } | |
326 | ||
327 | /* LFS versions of truncate are only needed on 32 bit machines */ | |
328 | #if BITS_PER_LONG == 32 | |
329 | asmlinkage long sys_truncate64(const char __user * path, loff_t length) | |
330 | { | |
331 | return do_sys_truncate(path, length); | |
332 | } | |
333 | ||
334 | asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length) | |
335 | { | |
336 | return do_sys_ftruncate(fd, length, 0); | |
337 | } | |
338 | #endif | |
339 | ||
340 | #ifdef __ARCH_WANT_SYS_UTIME | |
341 | ||
342 | /* | |
343 | * sys_utime() can be implemented in user-level using sys_utimes(). | |
344 | * Is this for backwards compatibility? If so, why not move it | |
345 | * into the appropriate arch directory (for those architectures that | |
346 | * need it). | |
347 | */ | |
348 | ||
349 | /* If times==NULL, set access and modification to current time, | |
350 | * must be owner or have write permission. | |
351 | * Else, update from *times, must be owner or super user. | |
352 | */ | |
353 | asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times) | |
354 | { | |
355 | int error; | |
356 | struct nameidata nd; | |
357 | struct inode * inode; | |
358 | struct iattr newattrs; | |
359 | ||
360 | error = user_path_walk(filename, &nd); | |
361 | if (error) | |
362 | goto out; | |
363 | inode = nd.dentry->d_inode; | |
364 | ||
365 | error = -EROFS; | |
366 | if (IS_RDONLY(inode)) | |
367 | goto dput_and_out; | |
368 | ||
369 | /* Don't worry, the checks are done in inode_change_ok() */ | |
370 | newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME; | |
371 | if (times) { | |
372 | error = -EPERM; | |
373 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) | |
374 | goto dput_and_out; | |
375 | ||
376 | error = get_user(newattrs.ia_atime.tv_sec, ×->actime); | |
377 | newattrs.ia_atime.tv_nsec = 0; | |
378 | if (!error) | |
379 | error = get_user(newattrs.ia_mtime.tv_sec, ×->modtime); | |
380 | newattrs.ia_mtime.tv_nsec = 0; | |
381 | if (error) | |
382 | goto dput_and_out; | |
383 | ||
384 | newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET; | |
385 | } else { | |
386 | error = -EACCES; | |
387 | if (IS_IMMUTABLE(inode)) | |
388 | goto dput_and_out; | |
389 | ||
390 | if (current->fsuid != inode->i_uid && | |
391 | (error = permission(inode,MAY_WRITE,&nd)) != 0) | |
392 | goto dput_and_out; | |
393 | } | |
394 | down(&inode->i_sem); | |
395 | error = notify_change(nd.dentry, &newattrs); | |
396 | up(&inode->i_sem); | |
397 | dput_and_out: | |
398 | path_release(&nd); | |
399 | out: | |
400 | return error; | |
401 | } | |
402 | ||
403 | #endif | |
404 | ||
405 | /* If times==NULL, set access and modification to current time, | |
406 | * must be owner or have write permission. | |
407 | * Else, update from *times, must be owner or super user. | |
408 | */ | |
409 | long do_utimes(char __user * filename, struct timeval * times) | |
410 | { | |
411 | int error; | |
412 | struct nameidata nd; | |
413 | struct inode * inode; | |
414 | struct iattr newattrs; | |
415 | ||
416 | error = user_path_walk(filename, &nd); | |
417 | ||
418 | if (error) | |
419 | goto out; | |
420 | inode = nd.dentry->d_inode; | |
421 | ||
422 | error = -EROFS; | |
423 | if (IS_RDONLY(inode)) | |
424 | goto dput_and_out; | |
425 | ||
426 | /* Don't worry, the checks are done in inode_change_ok() */ | |
427 | newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME; | |
428 | if (times) { | |
429 | error = -EPERM; | |
430 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) | |
431 | goto dput_and_out; | |
432 | ||
433 | newattrs.ia_atime.tv_sec = times[0].tv_sec; | |
434 | newattrs.ia_atime.tv_nsec = times[0].tv_usec * 1000; | |
435 | newattrs.ia_mtime.tv_sec = times[1].tv_sec; | |
436 | newattrs.ia_mtime.tv_nsec = times[1].tv_usec * 1000; | |
437 | newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET; | |
438 | } else { | |
439 | error = -EACCES; | |
440 | if (IS_IMMUTABLE(inode)) | |
441 | goto dput_and_out; | |
442 | ||
443 | if (current->fsuid != inode->i_uid && | |
444 | (error = permission(inode,MAY_WRITE,&nd)) != 0) | |
445 | goto dput_and_out; | |
446 | } | |
447 | down(&inode->i_sem); | |
448 | error = notify_change(nd.dentry, &newattrs); | |
449 | up(&inode->i_sem); | |
450 | dput_and_out: | |
451 | path_release(&nd); | |
452 | out: | |
453 | return error; | |
454 | } | |
455 | ||
456 | asmlinkage long sys_utimes(char __user * filename, struct timeval __user * utimes) | |
457 | { | |
458 | struct timeval times[2]; | |
459 | ||
460 | if (utimes && copy_from_user(×, utimes, sizeof(times))) | |
461 | return -EFAULT; | |
462 | return do_utimes(filename, utimes ? times : NULL); | |
463 | } | |
464 | ||
465 | ||
466 | /* | |
467 | * access() needs to use the real uid/gid, not the effective uid/gid. | |
468 | * We do this by temporarily clearing all FS-related capabilities and | |
469 | * switching the fsuid/fsgid around to the real ones. | |
470 | */ | |
471 | asmlinkage long sys_access(const char __user * filename, int mode) | |
472 | { | |
473 | struct nameidata nd; | |
474 | int old_fsuid, old_fsgid; | |
475 | kernel_cap_t old_cap; | |
476 | int res; | |
477 | ||
478 | if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */ | |
479 | return -EINVAL; | |
480 | ||
481 | old_fsuid = current->fsuid; | |
482 | old_fsgid = current->fsgid; | |
483 | old_cap = current->cap_effective; | |
484 | ||
485 | current->fsuid = current->uid; | |
486 | current->fsgid = current->gid; | |
487 | ||
488 | /* | |
489 | * Clear the capabilities if we switch to a non-root user | |
490 | * | |
491 | * FIXME: There is a race here against sys_capset. The | |
492 | * capabilities can change yet we will restore the old | |
493 | * value below. We should hold task_capabilities_lock, | |
494 | * but we cannot because user_path_walk can sleep. | |
495 | */ | |
496 | if (current->uid) | |
497 | cap_clear(current->cap_effective); | |
498 | else | |
499 | current->cap_effective = current->cap_permitted; | |
500 | ||
501 | res = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd); | |
502 | if (!res) { | |
503 | res = permission(nd.dentry->d_inode, mode, &nd); | |
504 | /* SuS v2 requires we report a read only fs too */ | |
505 | if(!res && (mode & S_IWOTH) && IS_RDONLY(nd.dentry->d_inode) | |
506 | && !special_file(nd.dentry->d_inode->i_mode)) | |
507 | res = -EROFS; | |
508 | path_release(&nd); | |
509 | } | |
510 | ||
511 | current->fsuid = old_fsuid; | |
512 | current->fsgid = old_fsgid; | |
513 | current->cap_effective = old_cap; | |
514 | ||
515 | return res; | |
516 | } | |
517 | ||
518 | asmlinkage long sys_chdir(const char __user * filename) | |
519 | { | |
520 | struct nameidata nd; | |
521 | int error; | |
522 | ||
523 | error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd); | |
524 | if (error) | |
525 | goto out; | |
526 | ||
527 | error = permission(nd.dentry->d_inode,MAY_EXEC,&nd); | |
528 | if (error) | |
529 | goto dput_and_out; | |
530 | ||
531 | set_fs_pwd(current->fs, nd.mnt, nd.dentry); | |
532 | ||
533 | dput_and_out: | |
534 | path_release(&nd); | |
535 | out: | |
536 | return error; | |
537 | } | |
538 | ||
539 | asmlinkage long sys_fchdir(unsigned int fd) | |
540 | { | |
541 | struct file *file; | |
542 | struct dentry *dentry; | |
543 | struct inode *inode; | |
544 | struct vfsmount *mnt; | |
545 | int error; | |
546 | ||
547 | error = -EBADF; | |
548 | file = fget(fd); | |
549 | if (!file) | |
550 | goto out; | |
551 | ||
552 | dentry = file->f_dentry; | |
553 | mnt = file->f_vfsmnt; | |
554 | inode = dentry->d_inode; | |
555 | ||
556 | error = -ENOTDIR; | |
557 | if (!S_ISDIR(inode->i_mode)) | |
558 | goto out_putf; | |
559 | ||
560 | error = permission(inode, MAY_EXEC, NULL); | |
561 | if (!error) | |
562 | set_fs_pwd(current->fs, mnt, dentry); | |
563 | out_putf: | |
564 | fput(file); | |
565 | out: | |
566 | return error; | |
567 | } | |
568 | ||
569 | asmlinkage long sys_chroot(const char __user * filename) | |
570 | { | |
571 | struct nameidata nd; | |
572 | int error; | |
573 | ||
574 | error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd); | |
575 | if (error) | |
576 | goto out; | |
577 | ||
578 | error = permission(nd.dentry->d_inode,MAY_EXEC,&nd); | |
579 | if (error) | |
580 | goto dput_and_out; | |
581 | ||
582 | error = -EPERM; | |
583 | if (!capable(CAP_SYS_CHROOT)) | |
584 | goto dput_and_out; | |
585 | ||
586 | set_fs_root(current->fs, nd.mnt, nd.dentry); | |
587 | set_fs_altroot(); | |
588 | error = 0; | |
589 | dput_and_out: | |
590 | path_release(&nd); | |
591 | out: | |
592 | return error; | |
593 | } | |
594 | ||
595 | asmlinkage long sys_fchmod(unsigned int fd, mode_t mode) | |
596 | { | |
597 | struct inode * inode; | |
598 | struct dentry * dentry; | |
599 | struct file * file; | |
600 | int err = -EBADF; | |
601 | struct iattr newattrs; | |
602 | ||
603 | file = fget(fd); | |
604 | if (!file) | |
605 | goto out; | |
606 | ||
607 | dentry = file->f_dentry; | |
608 | inode = dentry->d_inode; | |
609 | ||
610 | err = -EROFS; | |
611 | if (IS_RDONLY(inode)) | |
612 | goto out_putf; | |
613 | err = -EPERM; | |
614 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) | |
615 | goto out_putf; | |
616 | down(&inode->i_sem); | |
617 | if (mode == (mode_t) -1) | |
618 | mode = inode->i_mode; | |
619 | newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); | |
620 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; | |
621 | err = notify_change(dentry, &newattrs); | |
622 | up(&inode->i_sem); | |
623 | ||
624 | out_putf: | |
625 | fput(file); | |
626 | out: | |
627 | return err; | |
628 | } | |
629 | ||
630 | asmlinkage long sys_chmod(const char __user * filename, mode_t mode) | |
631 | { | |
632 | struct nameidata nd; | |
633 | struct inode * inode; | |
634 | int error; | |
635 | struct iattr newattrs; | |
636 | ||
637 | error = user_path_walk(filename, &nd); | |
638 | if (error) | |
639 | goto out; | |
640 | inode = nd.dentry->d_inode; | |
641 | ||
642 | error = -EROFS; | |
643 | if (IS_RDONLY(inode)) | |
644 | goto dput_and_out; | |
645 | ||
646 | error = -EPERM; | |
647 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) | |
648 | goto dput_and_out; | |
649 | ||
650 | down(&inode->i_sem); | |
651 | if (mode == (mode_t) -1) | |
652 | mode = inode->i_mode; | |
653 | newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); | |
654 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; | |
655 | error = notify_change(nd.dentry, &newattrs); | |
656 | up(&inode->i_sem); | |
657 | ||
658 | dput_and_out: | |
659 | path_release(&nd); | |
660 | out: | |
661 | return error; | |
662 | } | |
663 | ||
664 | static int chown_common(struct dentry * dentry, uid_t user, gid_t group) | |
665 | { | |
666 | struct inode * inode; | |
667 | int error; | |
668 | struct iattr newattrs; | |
669 | ||
670 | error = -ENOENT; | |
671 | if (!(inode = dentry->d_inode)) { | |
672 | printk(KERN_ERR "chown_common: NULL inode\n"); | |
673 | goto out; | |
674 | } | |
675 | error = -EROFS; | |
676 | if (IS_RDONLY(inode)) | |
677 | goto out; | |
678 | error = -EPERM; | |
679 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) | |
680 | goto out; | |
681 | newattrs.ia_valid = ATTR_CTIME; | |
682 | if (user != (uid_t) -1) { | |
683 | newattrs.ia_valid |= ATTR_UID; | |
684 | newattrs.ia_uid = user; | |
685 | } | |
686 | if (group != (gid_t) -1) { | |
687 | newattrs.ia_valid |= ATTR_GID; | |
688 | newattrs.ia_gid = group; | |
689 | } | |
690 | if (!S_ISDIR(inode->i_mode)) | |
691 | newattrs.ia_valid |= ATTR_KILL_SUID|ATTR_KILL_SGID; | |
692 | down(&inode->i_sem); | |
693 | error = notify_change(dentry, &newattrs); | |
694 | up(&inode->i_sem); | |
695 | out: | |
696 | return error; | |
697 | } | |
698 | ||
699 | asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group) | |
700 | { | |
701 | struct nameidata nd; | |
702 | int error; | |
703 | ||
704 | error = user_path_walk(filename, &nd); | |
705 | if (!error) { | |
706 | error = chown_common(nd.dentry, user, group); | |
707 | path_release(&nd); | |
708 | } | |
709 | return error; | |
710 | } | |
711 | ||
712 | asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group) | |
713 | { | |
714 | struct nameidata nd; | |
715 | int error; | |
716 | ||
717 | error = user_path_walk_link(filename, &nd); | |
718 | if (!error) { | |
719 | error = chown_common(nd.dentry, user, group); | |
720 | path_release(&nd); | |
721 | } | |
722 | return error; | |
723 | } | |
724 | ||
725 | ||
726 | asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group) | |
727 | { | |
728 | struct file * file; | |
729 | int error = -EBADF; | |
730 | ||
731 | file = fget(fd); | |
732 | if (file) { | |
733 | error = chown_common(file->f_dentry, user, group); | |
734 | fput(file); | |
735 | } | |
736 | return error; | |
737 | } | |
738 | ||
739 | /* | |
740 | * Note that while the flag value (low two bits) for sys_open means: | |
741 | * 00 - read-only | |
742 | * 01 - write-only | |
743 | * 10 - read-write | |
744 | * 11 - special | |
745 | * it is changed into | |
746 | * 00 - no permissions needed | |
747 | * 01 - read-permission | |
748 | * 10 - write-permission | |
749 | * 11 - read-write | |
750 | * for the internal routines (ie open_namei()/follow_link() etc). 00 is | |
751 | * used by symlinks. | |
752 | */ | |
753 | struct file *filp_open(const char * filename, int flags, int mode) | |
754 | { | |
755 | int namei_flags, error; | |
756 | struct nameidata nd; | |
757 | ||
758 | namei_flags = flags; | |
759 | if ((namei_flags+1) & O_ACCMODE) | |
760 | namei_flags++; | |
761 | if (namei_flags & O_TRUNC) | |
762 | namei_flags |= 2; | |
763 | ||
764 | error = open_namei(filename, namei_flags, mode, &nd); | |
765 | if (!error) | |
766 | return dentry_open(nd.dentry, nd.mnt, flags); | |
767 | ||
768 | return ERR_PTR(error); | |
769 | } | |
770 | ||
771 | EXPORT_SYMBOL(filp_open); | |
772 | ||
773 | struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags) | |
774 | { | |
775 | struct file * f; | |
776 | struct inode *inode; | |
777 | int error; | |
778 | ||
779 | error = -ENFILE; | |
780 | f = get_empty_filp(); | |
781 | if (!f) | |
782 | goto cleanup_dentry; | |
783 | f->f_flags = flags; | |
784 | f->f_mode = ((flags+1) & O_ACCMODE) | FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; | |
785 | inode = dentry->d_inode; | |
786 | if (f->f_mode & FMODE_WRITE) { | |
787 | error = get_write_access(inode); | |
788 | if (error) | |
789 | goto cleanup_file; | |
790 | } | |
791 | ||
792 | f->f_mapping = inode->i_mapping; | |
793 | f->f_dentry = dentry; | |
794 | f->f_vfsmnt = mnt; | |
795 | f->f_pos = 0; | |
796 | f->f_op = fops_get(inode->i_fop); | |
797 | file_move(f, &inode->i_sb->s_files); | |
798 | ||
799 | if (f->f_op && f->f_op->open) { | |
800 | error = f->f_op->open(inode,f); | |
801 | if (error) | |
802 | goto cleanup_all; | |
803 | } | |
804 | f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); | |
805 | ||
806 | file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping); | |
807 | ||
808 | /* NB: we're sure to have correct a_ops only after f_op->open */ | |
809 | if (f->f_flags & O_DIRECT) { | |
810 | if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO) { | |
811 | fput(f); | |
812 | f = ERR_PTR(-EINVAL); | |
813 | } | |
814 | } | |
815 | ||
816 | return f; | |
817 | ||
818 | cleanup_all: | |
819 | fops_put(f->f_op); | |
820 | if (f->f_mode & FMODE_WRITE) | |
821 | put_write_access(inode); | |
822 | file_kill(f); | |
823 | f->f_dentry = NULL; | |
824 | f->f_vfsmnt = NULL; | |
825 | cleanup_file: | |
826 | put_filp(f); | |
827 | cleanup_dentry: | |
828 | dput(dentry); | |
829 | mntput(mnt); | |
830 | return ERR_PTR(error); | |
831 | } | |
832 | ||
833 | EXPORT_SYMBOL(dentry_open); | |
834 | ||
835 | /* | |
836 | * Find an empty file descriptor entry, and mark it busy. | |
837 | */ | |
838 | int get_unused_fd(void) | |
839 | { | |
840 | struct files_struct * files = current->files; | |
841 | int fd, error; | |
842 | ||
843 | error = -EMFILE; | |
844 | spin_lock(&files->file_lock); | |
845 | ||
846 | repeat: | |
847 | fd = find_next_zero_bit(files->open_fds->fds_bits, | |
848 | files->max_fdset, | |
849 | files->next_fd); | |
850 | ||
851 | /* | |
852 | * N.B. For clone tasks sharing a files structure, this test | |
853 | * will limit the total number of files that can be opened. | |
854 | */ | |
855 | if (fd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) | |
856 | goto out; | |
857 | ||
858 | /* Do we need to expand the fd array or fd set? */ | |
859 | error = expand_files(files, fd); | |
860 | if (error < 0) | |
861 | goto out; | |
862 | ||
863 | if (error) { | |
864 | /* | |
865 | * If we needed to expand the fs array we | |
866 | * might have blocked - try again. | |
867 | */ | |
868 | error = -EMFILE; | |
869 | goto repeat; | |
870 | } | |
871 | ||
872 | FD_SET(fd, files->open_fds); | |
873 | FD_CLR(fd, files->close_on_exec); | |
874 | files->next_fd = fd + 1; | |
875 | #if 1 | |
876 | /* Sanity check */ | |
877 | if (files->fd[fd] != NULL) { | |
878 | printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd); | |
879 | files->fd[fd] = NULL; | |
880 | } | |
881 | #endif | |
882 | error = fd; | |
883 | ||
884 | out: | |
885 | spin_unlock(&files->file_lock); | |
886 | return error; | |
887 | } | |
888 | ||
889 | EXPORT_SYMBOL(get_unused_fd); | |
890 | ||
891 | static inline void __put_unused_fd(struct files_struct *files, unsigned int fd) | |
892 | { | |
893 | __FD_CLR(fd, files->open_fds); | |
894 | if (fd < files->next_fd) | |
895 | files->next_fd = fd; | |
896 | } | |
897 | ||
898 | void fastcall put_unused_fd(unsigned int fd) | |
899 | { | |
900 | struct files_struct *files = current->files; | |
901 | spin_lock(&files->file_lock); | |
902 | __put_unused_fd(files, fd); | |
903 | spin_unlock(&files->file_lock); | |
904 | } | |
905 | ||
906 | EXPORT_SYMBOL(put_unused_fd); | |
907 | ||
908 | /* | |
909 | * Install a file pointer in the fd array. | |
910 | * | |
911 | * The VFS is full of places where we drop the files lock between | |
912 | * setting the open_fds bitmap and installing the file in the file | |
913 | * array. At any such point, we are vulnerable to a dup2() race | |
914 | * installing a file in the array before us. We need to detect this and | |
915 | * fput() the struct file we are about to overwrite in this case. | |
916 | * | |
917 | * It should never happen - if we allow dup2() do it, _really_ bad things | |
918 | * will follow. | |
919 | */ | |
920 | ||
921 | void fastcall fd_install(unsigned int fd, struct file * file) | |
922 | { | |
923 | struct files_struct *files = current->files; | |
924 | spin_lock(&files->file_lock); | |
925 | if (unlikely(files->fd[fd] != NULL)) | |
926 | BUG(); | |
927 | files->fd[fd] = file; | |
928 | spin_unlock(&files->file_lock); | |
929 | } | |
930 | ||
931 | EXPORT_SYMBOL(fd_install); | |
932 | ||
933 | asmlinkage long sys_open(const char __user * filename, int flags, int mode) | |
934 | { | |
935 | char * tmp; | |
936 | int fd, error; | |
937 | ||
938 | #if BITS_PER_LONG != 32 | |
939 | flags |= O_LARGEFILE; | |
940 | #endif | |
941 | tmp = getname(filename); | |
942 | fd = PTR_ERR(tmp); | |
943 | if (!IS_ERR(tmp)) { | |
944 | fd = get_unused_fd(); | |
945 | if (fd >= 0) { | |
946 | struct file *f = filp_open(tmp, flags, mode); | |
947 | error = PTR_ERR(f); | |
948 | if (IS_ERR(f)) | |
949 | goto out_error; | |
950 | fd_install(fd, f); | |
951 | } | |
952 | out: | |
953 | putname(tmp); | |
954 | } | |
955 | return fd; | |
956 | ||
957 | out_error: | |
958 | put_unused_fd(fd); | |
959 | fd = error; | |
960 | goto out; | |
961 | } | |
962 | EXPORT_SYMBOL_GPL(sys_open); | |
963 | ||
964 | #ifndef __alpha__ | |
965 | ||
966 | /* | |
967 | * For backward compatibility? Maybe this should be moved | |
968 | * into arch/i386 instead? | |
969 | */ | |
970 | asmlinkage long sys_creat(const char __user * pathname, int mode) | |
971 | { | |
972 | return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode); | |
973 | } | |
974 | ||
975 | #endif | |
976 | ||
977 | /* | |
978 | * "id" is the POSIX thread ID. We use the | |
979 | * files pointer for this.. | |
980 | */ | |
981 | int filp_close(struct file *filp, fl_owner_t id) | |
982 | { | |
983 | int retval; | |
984 | ||
985 | /* Report and clear outstanding errors */ | |
986 | retval = filp->f_error; | |
987 | if (retval) | |
988 | filp->f_error = 0; | |
989 | ||
990 | if (!file_count(filp)) { | |
991 | printk(KERN_ERR "VFS: Close: file count is 0\n"); | |
992 | return retval; | |
993 | } | |
994 | ||
995 | if (filp->f_op && filp->f_op->flush) { | |
996 | int err = filp->f_op->flush(filp); | |
997 | if (!retval) | |
998 | retval = err; | |
999 | } | |
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; | |
1018 | ||
1019 | spin_lock(&files->file_lock); | |
1020 | if (fd >= files->max_fds) | |
1021 | goto out_unlock; | |
1022 | filp = files->fd[fd]; | |
1023 | if (!filp) | |
1024 | goto out_unlock; | |
1025 | files->fd[fd] = NULL; | |
1026 | FD_CLR(fd, files->close_on_exec); | |
1027 | __put_unused_fd(files, fd); | |
1028 | spin_unlock(&files->file_lock); | |
1029 | return filp_close(filp, files); | |
1030 | ||
1031 | out_unlock: | |
1032 | spin_unlock(&files->file_lock); | |
1033 | return -EBADF; | |
1034 | } | |
1035 | ||
1036 | EXPORT_SYMBOL(sys_close); | |
1037 | ||
1038 | /* | |
1039 | * This routine simulates a hangup on the tty, to arrange that users | |
1040 | * are given clean terminals at login time. | |
1041 | */ | |
1042 | asmlinkage long sys_vhangup(void) | |
1043 | { | |
1044 | if (capable(CAP_SYS_TTY_CONFIG)) { | |
1045 | tty_vhangup(current->signal->tty); | |
1046 | return 0; | |
1047 | } | |
1048 | return -EPERM; | |
1049 | } | |
1050 | ||
1051 | /* | |
1052 | * Called when an inode is about to be open. | |
1053 | * We use this to disallow opening large files on 32bit systems if | |
1054 | * the caller didn't specify O_LARGEFILE. On 64bit systems we force | |
1055 | * on this flag in sys_open. | |
1056 | */ | |
1057 | int generic_file_open(struct inode * inode, struct file * filp) | |
1058 | { | |
1059 | if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS) | |
1060 | return -EFBIG; | |
1061 | return 0; | |
1062 | } | |
1063 | ||
1064 | EXPORT_SYMBOL(generic_file_open); | |
1065 | ||
1066 | /* | |
1067 | * This is used by subsystems that don't want seekable | |
1068 | * file descriptors | |
1069 | */ | |
1070 | int nonseekable_open(struct inode *inode, struct file *filp) | |
1071 | { | |
1072 | filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); | |
1073 | return 0; | |
1074 | } | |
1075 | ||
1076 | EXPORT_SYMBOL(nonseekable_open); |