Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/seq_file.c | |
3 | * | |
4 | * helper functions for making synthetic files from sequences of records. | |
5 | * initial implementation -- AV, Oct 2001. | |
6 | */ | |
7 | ||
8 | #include <linux/fs.h> | |
9 | #include <linux/module.h> | |
10 | #include <linux/seq_file.h> | |
11 | #include <linux/slab.h> | |
12 | ||
13 | #include <asm/uaccess.h> | |
14 | #include <asm/page.h> | |
15 | ||
16 | /** | |
17 | * seq_open - initialize sequential file | |
18 | * @file: file we initialize | |
19 | * @op: method table describing the sequence | |
20 | * | |
21 | * seq_open() sets @file, associating it with a sequence described | |
22 | * by @op. @op->start() sets the iterator up and returns the first | |
23 | * element of sequence. @op->stop() shuts it down. @op->next() | |
24 | * returns the next element of sequence. @op->show() prints element | |
25 | * into the buffer. In case of error ->start() and ->next() return | |
26 | * ERR_PTR(error). In the end of sequence they return %NULL. ->show() | |
27 | * returns 0 in case of success and negative number in case of error. | |
521b5d0c | 28 | * Returning SEQ_SKIP means "discard this element and move on". |
1da177e4 | 29 | */ |
15ad7cdc | 30 | int seq_open(struct file *file, const struct seq_operations *op) |
1da177e4 | 31 | { |
1abe77b0 AV |
32 | struct seq_file *p = file->private_data; |
33 | ||
34 | if (!p) { | |
35 | p = kmalloc(sizeof(*p), GFP_KERNEL); | |
36 | if (!p) | |
37 | return -ENOMEM; | |
38 | file->private_data = p; | |
39 | } | |
1da177e4 | 40 | memset(p, 0, sizeof(*p)); |
0ac1759a | 41 | mutex_init(&p->lock); |
1da177e4 | 42 | p->op = op; |
1da177e4 LT |
43 | |
44 | /* | |
45 | * Wrappers around seq_open(e.g. swaps_open) need to be | |
46 | * aware of this. If they set f_version themselves, they | |
47 | * should call seq_open first and then set f_version. | |
48 | */ | |
49 | file->f_version = 0; | |
50 | ||
51 | /* SEQ files support lseek, but not pread/pwrite */ | |
52 | file->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE); | |
53 | return 0; | |
54 | } | |
55 | EXPORT_SYMBOL(seq_open); | |
56 | ||
57 | /** | |
58 | * seq_read - ->read() method for sequential files. | |
67be2dd1 MW |
59 | * @file: the file to read from |
60 | * @buf: the buffer to read to | |
61 | * @size: the maximum number of bytes to read | |
62 | * @ppos: the current position in the file | |
1da177e4 LT |
63 | * |
64 | * Ready-made ->f_op->read() | |
65 | */ | |
66 | ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) | |
67 | { | |
68 | struct seq_file *m = (struct seq_file *)file->private_data; | |
69 | size_t copied = 0; | |
70 | loff_t pos; | |
71 | size_t n; | |
72 | void *p; | |
73 | int err = 0; | |
74 | ||
0ac1759a | 75 | mutex_lock(&m->lock); |
1da177e4 LT |
76 | /* |
77 | * seq_file->op->..m_start/m_stop/m_next may do special actions | |
78 | * or optimisations based on the file->f_version, so we want to | |
79 | * pass the file->f_version to those methods. | |
80 | * | |
81 | * seq_file->version is just copy of f_version, and seq_file | |
82 | * methods can treat it simply as file version. | |
83 | * It is copied in first and copied out after all operations. | |
84 | * It is convenient to have it as part of structure to avoid the | |
85 | * need of passing another argument to all the seq_file methods. | |
86 | */ | |
87 | m->version = file->f_version; | |
88 | /* grab buffer if we didn't have one */ | |
89 | if (!m->buf) { | |
90 | m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL); | |
91 | if (!m->buf) | |
92 | goto Enomem; | |
93 | } | |
94 | /* if not empty - flush it first */ | |
95 | if (m->count) { | |
96 | n = min(m->count, size); | |
97 | err = copy_to_user(buf, m->buf + m->from, n); | |
98 | if (err) | |
99 | goto Efault; | |
100 | m->count -= n; | |
101 | m->from += n; | |
102 | size -= n; | |
103 | buf += n; | |
104 | copied += n; | |
105 | if (!m->count) | |
106 | m->index++; | |
107 | if (!size) | |
108 | goto Done; | |
109 | } | |
110 | /* we need at least one record in buffer */ | |
111 | while (1) { | |
112 | pos = m->index; | |
113 | p = m->op->start(m, &pos); | |
114 | err = PTR_ERR(p); | |
115 | if (!p || IS_ERR(p)) | |
116 | break; | |
117 | err = m->op->show(m, p); | |
521b5d0c | 118 | if (err < 0) |
1da177e4 | 119 | break; |
521b5d0c AV |
120 | if (unlikely(err)) |
121 | m->count = 0; | |
1da177e4 LT |
122 | if (m->count < m->size) |
123 | goto Fill; | |
124 | m->op->stop(m, p); | |
125 | kfree(m->buf); | |
126 | m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); | |
127 | if (!m->buf) | |
128 | goto Enomem; | |
129 | m->count = 0; | |
130 | m->version = 0; | |
131 | } | |
132 | m->op->stop(m, p); | |
133 | m->count = 0; | |
134 | goto Done; | |
135 | Fill: | |
136 | /* they want more? let's try to get some more */ | |
137 | while (m->count < size) { | |
138 | size_t offs = m->count; | |
139 | loff_t next = pos; | |
140 | p = m->op->next(m, p, &next); | |
141 | if (!p || IS_ERR(p)) { | |
142 | err = PTR_ERR(p); | |
143 | break; | |
144 | } | |
145 | err = m->op->show(m, p); | |
521b5d0c | 146 | if (m->count == m->size || err) { |
1da177e4 | 147 | m->count = offs; |
521b5d0c AV |
148 | if (likely(err <= 0)) |
149 | break; | |
1da177e4 LT |
150 | } |
151 | pos = next; | |
152 | } | |
153 | m->op->stop(m, p); | |
154 | n = min(m->count, size); | |
155 | err = copy_to_user(buf, m->buf, n); | |
156 | if (err) | |
157 | goto Efault; | |
158 | copied += n; | |
159 | m->count -= n; | |
160 | if (m->count) | |
161 | m->from = n; | |
162 | else | |
163 | pos++; | |
164 | m->index = pos; | |
165 | Done: | |
166 | if (!copied) | |
167 | copied = err; | |
168 | else | |
169 | *ppos += copied; | |
170 | file->f_version = m->version; | |
0ac1759a | 171 | mutex_unlock(&m->lock); |
1da177e4 LT |
172 | return copied; |
173 | Enomem: | |
174 | err = -ENOMEM; | |
175 | goto Done; | |
176 | Efault: | |
177 | err = -EFAULT; | |
178 | goto Done; | |
179 | } | |
180 | EXPORT_SYMBOL(seq_read); | |
181 | ||
182 | static int traverse(struct seq_file *m, loff_t offset) | |
183 | { | |
cb510b81 | 184 | loff_t pos = 0, index; |
1da177e4 LT |
185 | int error = 0; |
186 | void *p; | |
187 | ||
188 | m->version = 0; | |
cb510b81 | 189 | index = 0; |
1da177e4 | 190 | m->count = m->from = 0; |
cb510b81 AD |
191 | if (!offset) { |
192 | m->index = index; | |
1da177e4 | 193 | return 0; |
cb510b81 | 194 | } |
1da177e4 LT |
195 | if (!m->buf) { |
196 | m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL); | |
197 | if (!m->buf) | |
198 | return -ENOMEM; | |
199 | } | |
cb510b81 | 200 | p = m->op->start(m, &index); |
1da177e4 LT |
201 | while (p) { |
202 | error = PTR_ERR(p); | |
203 | if (IS_ERR(p)) | |
204 | break; | |
205 | error = m->op->show(m, p); | |
521b5d0c | 206 | if (error < 0) |
1da177e4 | 207 | break; |
521b5d0c AV |
208 | if (unlikely(error)) { |
209 | error = 0; | |
210 | m->count = 0; | |
211 | } | |
1da177e4 LT |
212 | if (m->count == m->size) |
213 | goto Eoverflow; | |
214 | if (pos + m->count > offset) { | |
215 | m->from = offset - pos; | |
216 | m->count -= m->from; | |
cb510b81 | 217 | m->index = index; |
1da177e4 LT |
218 | break; |
219 | } | |
220 | pos += m->count; | |
221 | m->count = 0; | |
222 | if (pos == offset) { | |
cb510b81 AD |
223 | index++; |
224 | m->index = index; | |
1da177e4 LT |
225 | break; |
226 | } | |
cb510b81 | 227 | p = m->op->next(m, p, &index); |
1da177e4 LT |
228 | } |
229 | m->op->stop(m, p); | |
230 | return error; | |
231 | ||
232 | Eoverflow: | |
233 | m->op->stop(m, p); | |
234 | kfree(m->buf); | |
235 | m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); | |
236 | return !m->buf ? -ENOMEM : -EAGAIN; | |
237 | } | |
238 | ||
239 | /** | |
240 | * seq_lseek - ->llseek() method for sequential files. | |
67be2dd1 MW |
241 | * @file: the file in question |
242 | * @offset: new position | |
243 | * @origin: 0 for absolute, 1 for relative position | |
1da177e4 LT |
244 | * |
245 | * Ready-made ->f_op->llseek() | |
246 | */ | |
247 | loff_t seq_lseek(struct file *file, loff_t offset, int origin) | |
248 | { | |
249 | struct seq_file *m = (struct seq_file *)file->private_data; | |
16abef0e | 250 | loff_t retval = -EINVAL; |
1da177e4 | 251 | |
0ac1759a | 252 | mutex_lock(&m->lock); |
1da177e4 LT |
253 | m->version = file->f_version; |
254 | switch (origin) { | |
255 | case 1: | |
256 | offset += file->f_pos; | |
257 | case 0: | |
258 | if (offset < 0) | |
259 | break; | |
260 | retval = offset; | |
261 | if (offset != file->f_pos) { | |
262 | while ((retval=traverse(m, offset)) == -EAGAIN) | |
263 | ; | |
264 | if (retval) { | |
265 | /* with extreme prejudice... */ | |
266 | file->f_pos = 0; | |
267 | m->version = 0; | |
268 | m->index = 0; | |
269 | m->count = 0; | |
270 | } else { | |
271 | retval = file->f_pos = offset; | |
272 | } | |
273 | } | |
274 | } | |
1da177e4 | 275 | file->f_version = m->version; |
00c5746d | 276 | mutex_unlock(&m->lock); |
1da177e4 LT |
277 | return retval; |
278 | } | |
279 | EXPORT_SYMBOL(seq_lseek); | |
280 | ||
281 | /** | |
282 | * seq_release - free the structures associated with sequential file. | |
283 | * @file: file in question | |
0f7fc9e4 | 284 | * @inode: file->f_path.dentry->d_inode |
1da177e4 LT |
285 | * |
286 | * Frees the structures associated with sequential file; can be used | |
287 | * as ->f_op->release() if you don't have private data to destroy. | |
288 | */ | |
289 | int seq_release(struct inode *inode, struct file *file) | |
290 | { | |
291 | struct seq_file *m = (struct seq_file *)file->private_data; | |
292 | kfree(m->buf); | |
293 | kfree(m); | |
294 | return 0; | |
295 | } | |
296 | EXPORT_SYMBOL(seq_release); | |
297 | ||
298 | /** | |
299 | * seq_escape - print string into buffer, escaping some characters | |
300 | * @m: target buffer | |
301 | * @s: string | |
302 | * @esc: set of characters that need escaping | |
303 | * | |
304 | * Puts string into buffer, replacing each occurrence of character from | |
305 | * @esc with usual octal escape. Returns 0 in case of success, -1 - in | |
306 | * case of overflow. | |
307 | */ | |
308 | int seq_escape(struct seq_file *m, const char *s, const char *esc) | |
309 | { | |
310 | char *end = m->buf + m->size; | |
311 | char *p; | |
312 | char c; | |
313 | ||
314 | for (p = m->buf + m->count; (c = *s) != '\0' && p < end; s++) { | |
315 | if (!strchr(esc, c)) { | |
316 | *p++ = c; | |
317 | continue; | |
318 | } | |
319 | if (p + 3 < end) { | |
320 | *p++ = '\\'; | |
321 | *p++ = '0' + ((c & 0300) >> 6); | |
322 | *p++ = '0' + ((c & 070) >> 3); | |
323 | *p++ = '0' + (c & 07); | |
324 | continue; | |
325 | } | |
326 | m->count = m->size; | |
327 | return -1; | |
328 | } | |
329 | m->count = p - m->buf; | |
330 | return 0; | |
331 | } | |
332 | EXPORT_SYMBOL(seq_escape); | |
333 | ||
334 | int seq_printf(struct seq_file *m, const char *f, ...) | |
335 | { | |
336 | va_list args; | |
337 | int len; | |
338 | ||
339 | if (m->count < m->size) { | |
340 | va_start(args, f); | |
341 | len = vsnprintf(m->buf + m->count, m->size - m->count, f, args); | |
342 | va_end(args); | |
343 | if (m->count + len < m->size) { | |
344 | m->count += len; | |
345 | return 0; | |
346 | } | |
347 | } | |
348 | m->count = m->size; | |
349 | return -1; | |
350 | } | |
351 | EXPORT_SYMBOL(seq_printf); | |
352 | ||
6092d048 RP |
353 | static char *mangle_path(char *s, char *p, char *esc) |
354 | { | |
355 | while (s <= p) { | |
356 | char c = *p++; | |
357 | if (!c) { | |
358 | return s; | |
359 | } else if (!strchr(esc, c)) { | |
360 | *s++ = c; | |
361 | } else if (s + 4 > p) { | |
362 | break; | |
363 | } else { | |
364 | *s++ = '\\'; | |
365 | *s++ = '0' + ((c & 0300) >> 6); | |
366 | *s++ = '0' + ((c & 070) >> 3); | |
367 | *s++ = '0' + (c & 07); | |
368 | } | |
369 | } | |
370 | return NULL; | |
371 | } | |
372 | ||
373 | /* | |
374 | * return the absolute path of 'dentry' residing in mount 'mnt'. | |
375 | */ | |
c32c2f63 | 376 | int seq_path(struct seq_file *m, struct path *path, char *esc) |
1da177e4 LT |
377 | { |
378 | if (m->count < m->size) { | |
379 | char *s = m->buf + m->count; | |
cf28b486 | 380 | char *p = d_path(path, s, m->size - m->count); |
1da177e4 | 381 | if (!IS_ERR(p)) { |
6092d048 RP |
382 | s = mangle_path(s, p, esc); |
383 | if (s) { | |
384 | p = m->buf + m->count; | |
385 | m->count = s - m->buf; | |
386 | return s - p; | |
1da177e4 LT |
387 | } |
388 | } | |
389 | } | |
390 | m->count = m->size; | |
391 | return -1; | |
392 | } | |
393 | EXPORT_SYMBOL(seq_path); | |
394 | ||
9d1bc601 MS |
395 | /* |
396 | * Same as seq_path, but relative to supplied root. | |
397 | * | |
398 | * root may be changed, see __d_path(). | |
399 | */ | |
400 | int seq_path_root(struct seq_file *m, struct path *path, struct path *root, | |
401 | char *esc) | |
402 | { | |
403 | int err = -ENAMETOOLONG; | |
404 | if (m->count < m->size) { | |
405 | char *s = m->buf + m->count; | |
406 | char *p; | |
407 | ||
408 | spin_lock(&dcache_lock); | |
409 | p = __d_path(path, root, s, m->size - m->count); | |
410 | spin_unlock(&dcache_lock); | |
411 | err = PTR_ERR(p); | |
412 | if (!IS_ERR(p)) { | |
413 | s = mangle_path(s, p, esc); | |
414 | if (s) { | |
415 | p = m->buf + m->count; | |
416 | m->count = s - m->buf; | |
417 | return 0; | |
418 | } | |
419 | } | |
420 | } | |
421 | m->count = m->size; | |
422 | return err; | |
423 | } | |
424 | ||
6092d048 RP |
425 | /* |
426 | * returns the path of the 'dentry' from the root of its filesystem. | |
427 | */ | |
428 | int seq_dentry(struct seq_file *m, struct dentry *dentry, char *esc) | |
429 | { | |
430 | if (m->count < m->size) { | |
431 | char *s = m->buf + m->count; | |
432 | char *p = dentry_path(dentry, s, m->size - m->count); | |
433 | if (!IS_ERR(p)) { | |
434 | s = mangle_path(s, p, esc); | |
435 | if (s) { | |
436 | p = m->buf + m->count; | |
437 | m->count = s - m->buf; | |
438 | return s - p; | |
439 | } | |
440 | } | |
441 | } | |
442 | m->count = m->size; | |
443 | return -1; | |
444 | } | |
445 | ||
1da177e4 LT |
446 | static void *single_start(struct seq_file *p, loff_t *pos) |
447 | { | |
448 | return NULL + (*pos == 0); | |
449 | } | |
450 | ||
451 | static void *single_next(struct seq_file *p, void *v, loff_t *pos) | |
452 | { | |
453 | ++*pos; | |
454 | return NULL; | |
455 | } | |
456 | ||
457 | static void single_stop(struct seq_file *p, void *v) | |
458 | { | |
459 | } | |
460 | ||
461 | int single_open(struct file *file, int (*show)(struct seq_file *, void *), | |
462 | void *data) | |
463 | { | |
464 | struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL); | |
465 | int res = -ENOMEM; | |
466 | ||
467 | if (op) { | |
468 | op->start = single_start; | |
469 | op->next = single_next; | |
470 | op->stop = single_stop; | |
471 | op->show = show; | |
472 | res = seq_open(file, op); | |
473 | if (!res) | |
474 | ((struct seq_file *)file->private_data)->private = data; | |
475 | else | |
476 | kfree(op); | |
477 | } | |
478 | return res; | |
479 | } | |
480 | EXPORT_SYMBOL(single_open); | |
481 | ||
482 | int single_release(struct inode *inode, struct file *file) | |
483 | { | |
15ad7cdc | 484 | const struct seq_operations *op = ((struct seq_file *)file->private_data)->op; |
1da177e4 LT |
485 | int res = seq_release(inode, file); |
486 | kfree(op); | |
487 | return res; | |
488 | } | |
489 | EXPORT_SYMBOL(single_release); | |
490 | ||
491 | int seq_release_private(struct inode *inode, struct file *file) | |
492 | { | |
493 | struct seq_file *seq = file->private_data; | |
494 | ||
495 | kfree(seq->private); | |
496 | seq->private = NULL; | |
497 | return seq_release(inode, file); | |
498 | } | |
499 | EXPORT_SYMBOL(seq_release_private); | |
500 | ||
39699037 PE |
501 | void *__seq_open_private(struct file *f, const struct seq_operations *ops, |
502 | int psize) | |
503 | { | |
504 | int rc; | |
505 | void *private; | |
506 | struct seq_file *seq; | |
507 | ||
508 | private = kzalloc(psize, GFP_KERNEL); | |
509 | if (private == NULL) | |
510 | goto out; | |
511 | ||
512 | rc = seq_open(f, ops); | |
513 | if (rc < 0) | |
514 | goto out_free; | |
515 | ||
516 | seq = f->private_data; | |
517 | seq->private = private; | |
518 | return private; | |
519 | ||
520 | out_free: | |
521 | kfree(private); | |
522 | out: | |
523 | return NULL; | |
524 | } | |
525 | EXPORT_SYMBOL(__seq_open_private); | |
526 | ||
527 | int seq_open_private(struct file *filp, const struct seq_operations *ops, | |
528 | int psize) | |
529 | { | |
530 | return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM; | |
531 | } | |
532 | EXPORT_SYMBOL(seq_open_private); | |
533 | ||
1da177e4 LT |
534 | int seq_putc(struct seq_file *m, char c) |
535 | { | |
536 | if (m->count < m->size) { | |
537 | m->buf[m->count++] = c; | |
538 | return 0; | |
539 | } | |
540 | return -1; | |
541 | } | |
542 | EXPORT_SYMBOL(seq_putc); | |
543 | ||
544 | int seq_puts(struct seq_file *m, const char *s) | |
545 | { | |
546 | int len = strlen(s); | |
547 | if (m->count + len < m->size) { | |
548 | memcpy(m->buf + m->count, s, len); | |
549 | m->count += len; | |
550 | return 0; | |
551 | } | |
552 | m->count = m->size; | |
553 | return -1; | |
554 | } | |
555 | EXPORT_SYMBOL(seq_puts); | |
bcf67e16 PE |
556 | |
557 | struct list_head *seq_list_start(struct list_head *head, loff_t pos) | |
558 | { | |
559 | struct list_head *lh; | |
560 | ||
561 | list_for_each(lh, head) | |
562 | if (pos-- == 0) | |
563 | return lh; | |
564 | ||
565 | return NULL; | |
566 | } | |
567 | ||
568 | EXPORT_SYMBOL(seq_list_start); | |
569 | ||
570 | struct list_head *seq_list_start_head(struct list_head *head, loff_t pos) | |
571 | { | |
572 | if (!pos) | |
573 | return head; | |
574 | ||
575 | return seq_list_start(head, pos - 1); | |
576 | } | |
577 | ||
578 | EXPORT_SYMBOL(seq_list_start_head); | |
579 | ||
580 | struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos) | |
581 | { | |
582 | struct list_head *lh; | |
583 | ||
584 | lh = ((struct list_head *)v)->next; | |
585 | ++*ppos; | |
586 | return lh == head ? NULL : lh; | |
587 | } | |
588 | ||
589 | EXPORT_SYMBOL(seq_list_next); |