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b2441318 1// SPDX-License-Identifier: GPL-2.0
1da177e4
LT
2/*
3 * linux/fs/seq_file.c
4 *
5 * helper functions for making synthetic files from sequences of records.
6 * initial implementation -- AV, Oct 2001.
7 */
8
9#include <linux/fs.h>
630d9c47 10#include <linux/export.h>
1da177e4 11#include <linux/seq_file.h>
058504ed 12#include <linux/vmalloc.h>
1da177e4 13#include <linux/slab.h>
adb37c4c 14#include <linux/cred.h>
058504ed 15#include <linux/mm.h>
37607102 16#include <linux/printk.h>
25c6bb76 17#include <linux/string_helpers.h>
1da177e4 18
7c0f6ba6 19#include <linux/uaccess.h>
1da177e4
LT
20#include <asm/page.h>
21
e075f591
KH
22static void seq_set_overflow(struct seq_file *m)
23{
24 m->count = m->size;
25}
26
058504ed
HC
27static void *seq_buf_alloc(unsigned long size)
28{
a7c3e901 29 return kvmalloc(size, GFP_KERNEL);
058504ed
HC
30}
31
1da177e4
LT
32/**
33 * seq_open - initialize sequential file
34 * @file: file we initialize
35 * @op: method table describing the sequence
36 *
37 * seq_open() sets @file, associating it with a sequence described
38 * by @op. @op->start() sets the iterator up and returns the first
39 * element of sequence. @op->stop() shuts it down. @op->next()
40 * returns the next element of sequence. @op->show() prints element
41 * into the buffer. In case of error ->start() and ->next() return
42 * ERR_PTR(error). In the end of sequence they return %NULL. ->show()
43 * returns 0 in case of success and negative number in case of error.
521b5d0c 44 * Returning SEQ_SKIP means "discard this element and move on".
460b865e
YD
45 * Note: seq_open() will allocate a struct seq_file and store its
46 * pointer in @file->private_data. This pointer should not be modified.
1da177e4 47 */
15ad7cdc 48int seq_open(struct file *file, const struct seq_operations *op)
1da177e4 49{
189f9841
YD
50 struct seq_file *p;
51
52 WARN_ON(file->private_data);
53
54 p = kzalloc(sizeof(*p), GFP_KERNEL);
55 if (!p)
56 return -ENOMEM;
57
58 file->private_data = p;
1abe77b0 59
0ac1759a 60 mutex_init(&p->lock);
1da177e4 61 p->op = op;
34dbbcdb
LT
62
63 // No refcounting: the lifetime of 'p' is constrained
64 // to the lifetime of the file.
65 p->file = file;
1da177e4
LT
66
67 /*
68 * Wrappers around seq_open(e.g. swaps_open) need to be
69 * aware of this. If they set f_version themselves, they
70 * should call seq_open first and then set f_version.
71 */
72 file->f_version = 0;
73
8f19d472
EB
74 /*
75 * seq_files support lseek() and pread(). They do not implement
76 * write() at all, but we clear FMODE_PWRITE here for historical
77 * reasons.
78 *
79 * If a client of seq_files a) implements file.write() and b) wishes to
80 * support pwrite() then that client will need to implement its own
81 * file.open() which calls seq_open() and then sets FMODE_PWRITE.
82 */
83 file->f_mode &= ~FMODE_PWRITE;
1da177e4
LT
84 return 0;
85}
86EXPORT_SYMBOL(seq_open);
87
33da8892
EB
88static int traverse(struct seq_file *m, loff_t offset)
89{
90 loff_t pos = 0, index;
91 int error = 0;
92 void *p;
93
94 m->version = 0;
95 index = 0;
96 m->count = m->from = 0;
97 if (!offset) {
98 m->index = index;
99 return 0;
100 }
101 if (!m->buf) {
058504ed 102 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
33da8892
EB
103 if (!m->buf)
104 return -ENOMEM;
105 }
106 p = m->op->start(m, &index);
107 while (p) {
108 error = PTR_ERR(p);
109 if (IS_ERR(p))
110 break;
111 error = m->op->show(m, p);
112 if (error < 0)
113 break;
114 if (unlikely(error)) {
115 error = 0;
116 m->count = 0;
117 }
1f33c41c 118 if (seq_has_overflowed(m))
33da8892
EB
119 goto Eoverflow;
120 if (pos + m->count > offset) {
121 m->from = offset - pos;
122 m->count -= m->from;
123 m->index = index;
124 break;
125 }
126 pos += m->count;
127 m->count = 0;
128 if (pos == offset) {
129 index++;
130 m->index = index;
131 break;
132 }
133 p = m->op->next(m, p, &index);
134 }
135 m->op->stop(m, p);
f01d1d54 136 m->index = index;
33da8892
EB
137 return error;
138
139Eoverflow:
140 m->op->stop(m, p);
058504ed 141 kvfree(m->buf);
801a7605 142 m->count = 0;
058504ed 143 m->buf = seq_buf_alloc(m->size <<= 1);
33da8892
EB
144 return !m->buf ? -ENOMEM : -EAGAIN;
145}
146
1da177e4
LT
147/**
148 * seq_read - ->read() method for sequential files.
67be2dd1
MW
149 * @file: the file to read from
150 * @buf: the buffer to read to
151 * @size: the maximum number of bytes to read
152 * @ppos: the current position in the file
1da177e4
LT
153 *
154 * Ready-made ->f_op->read()
155 */
156ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
157{
8209e2f4 158 struct seq_file *m = file->private_data;
1da177e4
LT
159 size_t copied = 0;
160 loff_t pos;
161 size_t n;
162 void *p;
163 int err = 0;
164
0ac1759a 165 mutex_lock(&m->lock);
8f19d472 166
7904ac84
EC
167 /*
168 * seq_file->op->..m_start/m_stop/m_next may do special actions
169 * or optimisations based on the file->f_version, so we want to
170 * pass the file->f_version to those methods.
171 *
172 * seq_file->version is just copy of f_version, and seq_file
173 * methods can treat it simply as file version.
174 * It is copied in first and copied out after all operations.
175 * It is convenient to have it as part of structure to avoid the
176 * need of passing another argument to all the seq_file methods.
177 */
178 m->version = file->f_version;
179
e522751d
TM
180 /*
181 * if request is to read from zero offset, reset iterator to first
182 * record as it might have been already advanced by previous requests
183 */
184 if (*ppos == 0)
185 m->index = 0;
186
8f19d472
EB
187 /* Don't assume *ppos is where we left it */
188 if (unlikely(*ppos != m->read_pos)) {
8f19d472
EB
189 while ((err = traverse(m, *ppos)) == -EAGAIN)
190 ;
191 if (err) {
192 /* With prejudice... */
193 m->read_pos = 0;
194 m->version = 0;
195 m->index = 0;
196 m->count = 0;
197 goto Done;
7904ac84
EC
198 } else {
199 m->read_pos = *ppos;
8f19d472
EB
200 }
201 }
202
1da177e4
LT
203 /* grab buffer if we didn't have one */
204 if (!m->buf) {
058504ed 205 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
1da177e4
LT
206 if (!m->buf)
207 goto Enomem;
208 }
209 /* if not empty - flush it first */
210 if (m->count) {
211 n = min(m->count, size);
212 err = copy_to_user(buf, m->buf + m->from, n);
213 if (err)
214 goto Efault;
215 m->count -= n;
216 m->from += n;
217 size -= n;
218 buf += n;
219 copied += n;
088bf2ff
VN
220 if (!m->count) {
221 m->from = 0;
1da177e4 222 m->index++;
088bf2ff 223 }
1da177e4
LT
224 if (!size)
225 goto Done;
226 }
227 /* we need at least one record in buffer */
4cdfe84b
AV
228 pos = m->index;
229 p = m->op->start(m, &pos);
1da177e4 230 while (1) {
1da177e4
LT
231 err = PTR_ERR(p);
232 if (!p || IS_ERR(p))
233 break;
234 err = m->op->show(m, p);
521b5d0c 235 if (err < 0)
1da177e4 236 break;
521b5d0c
AV
237 if (unlikely(err))
238 m->count = 0;
4cdfe84b
AV
239 if (unlikely(!m->count)) {
240 p = m->op->next(m, p, &pos);
241 m->index = pos;
242 continue;
243 }
1da177e4
LT
244 if (m->count < m->size)
245 goto Fill;
246 m->op->stop(m, p);
058504ed 247 kvfree(m->buf);
801a7605 248 m->count = 0;
058504ed 249 m->buf = seq_buf_alloc(m->size <<= 1);
1da177e4
LT
250 if (!m->buf)
251 goto Enomem;
1da177e4 252 m->version = 0;
4cdfe84b
AV
253 pos = m->index;
254 p = m->op->start(m, &pos);
1da177e4
LT
255 }
256 m->op->stop(m, p);
257 m->count = 0;
258 goto Done;
259Fill:
260 /* they want more? let's try to get some more */
261 while (m->count < size) {
262 size_t offs = m->count;
263 loff_t next = pos;
264 p = m->op->next(m, p, &next);
265 if (!p || IS_ERR(p)) {
266 err = PTR_ERR(p);
267 break;
268 }
269 err = m->op->show(m, p);
1f33c41c 270 if (seq_has_overflowed(m) || err) {
1da177e4 271 m->count = offs;
521b5d0c
AV
272 if (likely(err <= 0))
273 break;
1da177e4
LT
274 }
275 pos = next;
276 }
277 m->op->stop(m, p);
278 n = min(m->count, size);
279 err = copy_to_user(buf, m->buf, n);
280 if (err)
281 goto Efault;
282 copied += n;
283 m->count -= n;
284 if (m->count)
285 m->from = n;
286 else
287 pos++;
288 m->index = pos;
289Done:
290 if (!copied)
291 copied = err;
8f19d472 292 else {
1da177e4 293 *ppos += copied;
8f19d472
EB
294 m->read_pos += copied;
295 }
1da177e4 296 file->f_version = m->version;
0ac1759a 297 mutex_unlock(&m->lock);
1da177e4
LT
298 return copied;
299Enomem:
300 err = -ENOMEM;
301 goto Done;
302Efault:
303 err = -EFAULT;
304 goto Done;
305}
306EXPORT_SYMBOL(seq_read);
307
1da177e4
LT
308/**
309 * seq_lseek - ->llseek() method for sequential files.
67be2dd1
MW
310 * @file: the file in question
311 * @offset: new position
254adaa4 312 * @whence: 0 for absolute, 1 for relative position
1da177e4
LT
313 *
314 * Ready-made ->f_op->llseek()
315 */
965c8e59 316loff_t seq_lseek(struct file *file, loff_t offset, int whence)
1da177e4 317{
8209e2f4 318 struct seq_file *m = file->private_data;
16abef0e 319 loff_t retval = -EINVAL;
1da177e4 320
0ac1759a 321 mutex_lock(&m->lock);
1da177e4 322 m->version = file->f_version;
965c8e59 323 switch (whence) {
5e62adef
AM
324 case SEEK_CUR:
325 offset += file->f_pos;
326 case SEEK_SET:
327 if (offset < 0)
328 break;
329 retval = offset;
330 if (offset != m->read_pos) {
331 while ((retval = traverse(m, offset)) == -EAGAIN)
332 ;
333 if (retval) {
334 /* with extreme prejudice... */
335 file->f_pos = 0;
336 m->read_pos = 0;
337 m->version = 0;
338 m->index = 0;
339 m->count = 0;
340 } else {
341 m->read_pos = offset;
342 retval = file->f_pos = offset;
1da177e4 343 }
05e16745
GZ
344 } else {
345 file->f_pos = offset;
5e62adef 346 }
1da177e4 347 }
1da177e4 348 file->f_version = m->version;
00c5746d 349 mutex_unlock(&m->lock);
1da177e4
LT
350 return retval;
351}
352EXPORT_SYMBOL(seq_lseek);
353
354/**
355 * seq_release - free the structures associated with sequential file.
356 * @file: file in question
6131ffaa 357 * @inode: its inode
1da177e4
LT
358 *
359 * Frees the structures associated with sequential file; can be used
360 * as ->f_op->release() if you don't have private data to destroy.
361 */
362int seq_release(struct inode *inode, struct file *file)
363{
8209e2f4 364 struct seq_file *m = file->private_data;
058504ed 365 kvfree(m->buf);
1da177e4
LT
366 kfree(m);
367 return 0;
368}
369EXPORT_SYMBOL(seq_release);
370
371/**
372 * seq_escape - print string into buffer, escaping some characters
373 * @m: target buffer
374 * @s: string
375 * @esc: set of characters that need escaping
376 *
377 * Puts string into buffer, replacing each occurrence of character from
6798a8ca
JP
378 * @esc with usual octal escape.
379 * Use seq_has_overflowed() to check for errors.
1da177e4 380 */
6798a8ca 381void seq_escape(struct seq_file *m, const char *s, const char *esc)
1da177e4 382{
25c6bb76
AS
383 char *buf;
384 size_t size = seq_get_buf(m, &buf);
385 int ret;
1da177e4 386
25c6bb76
AS
387 ret = string_escape_str(s, buf, size, ESCAPE_OCTAL, esc);
388 seq_commit(m, ret < size ? ret : -1);
1da177e4
LT
389}
390EXPORT_SYMBOL(seq_escape);
391
6798a8ca 392void seq_vprintf(struct seq_file *m, const char *f, va_list args)
1da177e4 393{
1da177e4
LT
394 int len;
395
396 if (m->count < m->size) {
1da177e4 397 len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
1da177e4
LT
398 if (m->count + len < m->size) {
399 m->count += len;
6798a8ca 400 return;
1da177e4
LT
401 }
402 }
e075f591 403 seq_set_overflow(m);
1da177e4 404}
a4808147
SW
405EXPORT_SYMBOL(seq_vprintf);
406
6798a8ca 407void seq_printf(struct seq_file *m, const char *f, ...)
a4808147 408{
a4808147
SW
409 va_list args;
410
411 va_start(args, f);
6798a8ca 412 seq_vprintf(m, f, args);
a4808147 413 va_end(args);
a4808147 414}
1da177e4
LT
415EXPORT_SYMBOL(seq_printf);
416
74e2f334 417/**
958086d1
TE
418 * mangle_path - mangle and copy path to buffer beginning
419 * @s: buffer start
420 * @p: beginning of path in above buffer
421 * @esc: set of characters that need escaping
74e2f334
TE
422 *
423 * Copy the path from @p to @s, replacing each occurrence of character from
424 * @esc with usual octal escape.
425 * Returns pointer past last written character in @s, or NULL in case of
426 * failure.
427 */
8c9379e9 428char *mangle_path(char *s, const char *p, const char *esc)
6092d048
RP
429{
430 while (s <= p) {
431 char c = *p++;
432 if (!c) {
433 return s;
434 } else if (!strchr(esc, c)) {
435 *s++ = c;
436 } else if (s + 4 > p) {
437 break;
438 } else {
439 *s++ = '\\';
440 *s++ = '0' + ((c & 0300) >> 6);
441 *s++ = '0' + ((c & 070) >> 3);
442 *s++ = '0' + (c & 07);
443 }
444 }
445 return NULL;
446}
604094f4 447EXPORT_SYMBOL(mangle_path);
6092d048 448
52afeefb
AV
449/**
450 * seq_path - seq_file interface to print a pathname
451 * @m: the seq_file handle
452 * @path: the struct path to print
453 * @esc: set of characters to escape in the output
454 *
455 * return the absolute path of 'path', as represented by the
456 * dentry / mnt pair in the path parameter.
6092d048 457 */
8c9379e9 458int seq_path(struct seq_file *m, const struct path *path, const char *esc)
1da177e4 459{
f8439806
MS
460 char *buf;
461 size_t size = seq_get_buf(m, &buf);
462 int res = -1;
463
464 if (size) {
465 char *p = d_path(path, buf, size);
1da177e4 466 if (!IS_ERR(p)) {
f8439806
MS
467 char *end = mangle_path(buf, p, esc);
468 if (end)
469 res = end - buf;
1da177e4
LT
470 }
471 }
f8439806
MS
472 seq_commit(m, res);
473
474 return res;
1da177e4
LT
475}
476EXPORT_SYMBOL(seq_path);
477
2726d566
MS
478/**
479 * seq_file_path - seq_file interface to print a pathname of a file
480 * @m: the seq_file handle
481 * @file: the struct file to print
482 * @esc: set of characters to escape in the output
483 *
484 * return the absolute path to the file.
485 */
486int seq_file_path(struct seq_file *m, struct file *file, const char *esc)
487{
488 return seq_path(m, &file->f_path, esc);
489}
490EXPORT_SYMBOL(seq_file_path);
491
9d1bc601
MS
492/*
493 * Same as seq_path, but relative to supplied root.
9d1bc601 494 */
8c9379e9
AV
495int seq_path_root(struct seq_file *m, const struct path *path,
496 const struct path *root, const char *esc)
9d1bc601 497{
f8439806
MS
498 char *buf;
499 size_t size = seq_get_buf(m, &buf);
500 int res = -ENAMETOOLONG;
501
502 if (size) {
9d1bc601
MS
503 char *p;
504
f8439806 505 p = __d_path(path, root, buf, size);
02125a82
AV
506 if (!p)
507 return SEQ_SKIP;
f8439806 508 res = PTR_ERR(p);
9d1bc601 509 if (!IS_ERR(p)) {
f8439806
MS
510 char *end = mangle_path(buf, p, esc);
511 if (end)
512 res = end - buf;
513 else
514 res = -ENAMETOOLONG;
9d1bc601
MS
515 }
516 }
f8439806
MS
517 seq_commit(m, res);
518
02125a82 519 return res < 0 && res != -ENAMETOOLONG ? res : 0;
9d1bc601
MS
520}
521
6092d048
RP
522/*
523 * returns the path of the 'dentry' from the root of its filesystem.
524 */
8c9379e9 525int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc)
6092d048 526{
f8439806
MS
527 char *buf;
528 size_t size = seq_get_buf(m, &buf);
529 int res = -1;
530
531 if (size) {
532 char *p = dentry_path(dentry, buf, size);
6092d048 533 if (!IS_ERR(p)) {
f8439806
MS
534 char *end = mangle_path(buf, p, esc);
535 if (end)
536 res = end - buf;
6092d048
RP
537 }
538 }
f8439806
MS
539 seq_commit(m, res);
540
541 return res;
6092d048 542}
c8d3fe02 543EXPORT_SYMBOL(seq_dentry);
6092d048 544
1da177e4
LT
545static void *single_start(struct seq_file *p, loff_t *pos)
546{
547 return NULL + (*pos == 0);
548}
549
550static void *single_next(struct seq_file *p, void *v, loff_t *pos)
551{
552 ++*pos;
553 return NULL;
554}
555
556static void single_stop(struct seq_file *p, void *v)
557{
558}
559
560int single_open(struct file *file, int (*show)(struct seq_file *, void *),
561 void *data)
562{
563 struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL);
564 int res = -ENOMEM;
565
566 if (op) {
567 op->start = single_start;
568 op->next = single_next;
569 op->stop = single_stop;
570 op->show = show;
571 res = seq_open(file, op);
572 if (!res)
573 ((struct seq_file *)file->private_data)->private = data;
574 else
575 kfree(op);
576 }
577 return res;
578}
579EXPORT_SYMBOL(single_open);
580
2043f495
AV
581int single_open_size(struct file *file, int (*show)(struct seq_file *, void *),
582 void *data, size_t size)
583{
058504ed 584 char *buf = seq_buf_alloc(size);
2043f495
AV
585 int ret;
586 if (!buf)
587 return -ENOMEM;
588 ret = single_open(file, show, data);
589 if (ret) {
058504ed 590 kvfree(buf);
2043f495
AV
591 return ret;
592 }
593 ((struct seq_file *)file->private_data)->buf = buf;
594 ((struct seq_file *)file->private_data)->size = size;
595 return 0;
596}
597EXPORT_SYMBOL(single_open_size);
598
1da177e4
LT
599int single_release(struct inode *inode, struct file *file)
600{
15ad7cdc 601 const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
1da177e4
LT
602 int res = seq_release(inode, file);
603 kfree(op);
604 return res;
605}
606EXPORT_SYMBOL(single_release);
607
608int seq_release_private(struct inode *inode, struct file *file)
609{
610 struct seq_file *seq = file->private_data;
611
612 kfree(seq->private);
613 seq->private = NULL;
614 return seq_release(inode, file);
615}
616EXPORT_SYMBOL(seq_release_private);
617
39699037
PE
618void *__seq_open_private(struct file *f, const struct seq_operations *ops,
619 int psize)
620{
621 int rc;
622 void *private;
623 struct seq_file *seq;
624
625 private = kzalloc(psize, GFP_KERNEL);
626 if (private == NULL)
627 goto out;
628
629 rc = seq_open(f, ops);
630 if (rc < 0)
631 goto out_free;
632
633 seq = f->private_data;
634 seq->private = private;
635 return private;
636
637out_free:
638 kfree(private);
639out:
640 return NULL;
641}
642EXPORT_SYMBOL(__seq_open_private);
643
644int seq_open_private(struct file *filp, const struct seq_operations *ops,
645 int psize)
646{
647 return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;
648}
649EXPORT_SYMBOL(seq_open_private);
650
6798a8ca 651void seq_putc(struct seq_file *m, char c)
1da177e4 652{
6798a8ca
JP
653 if (m->count >= m->size)
654 return;
655
656 m->buf[m->count++] = c;
1da177e4
LT
657}
658EXPORT_SYMBOL(seq_putc);
659
6798a8ca 660void seq_puts(struct seq_file *m, const char *s)
1da177e4
LT
661{
662 int len = strlen(s);
6798a8ca
JP
663
664 if (m->count + len >= m->size) {
665 seq_set_overflow(m);
666 return;
1da177e4 667 }
6798a8ca
JP
668 memcpy(m->buf + m->count, s, len);
669 m->count += len;
1da177e4
LT
670}
671EXPORT_SYMBOL(seq_puts);
bcf67e16 672
1ac101a5
KH
673/*
674 * A helper routine for putting decimal numbers without rich format of printf().
675 * only 'unsigned long long' is supported.
75ba1d07 676 * This routine will put strlen(delimiter) + number into seq_file.
1ac101a5
KH
677 * This routine is very quick when you show lots of numbers.
678 * In usual cases, it will be better to use seq_printf(). It's easier to read.
679 */
75ba1d07 680void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
6798a8ca 681 unsigned long long num)
1ac101a5
KH
682{
683 int len;
684
685 if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */
686 goto overflow;
687
75ba1d07
JP
688 len = strlen(delimiter);
689 if (m->count + len >= m->size)
690 goto overflow;
691
692 memcpy(m->buf + m->count, delimiter, len);
693 m->count += len;
694
695 if (m->count + 1 >= m->size)
696 goto overflow;
1ac101a5
KH
697
698 if (num < 10) {
699 m->buf[m->count++] = num + '0';
6798a8ca 700 return;
1ac101a5
KH
701 }
702
703 len = num_to_str(m->buf + m->count, m->size - m->count, num);
704 if (!len)
705 goto overflow;
75ba1d07 706
1ac101a5 707 m->count += len;
6798a8ca
JP
708 return;
709
1ac101a5 710overflow:
e075f591 711 seq_set_overflow(m);
1ac101a5
KH
712}
713EXPORT_SYMBOL(seq_put_decimal_ull);
714
75ba1d07 715void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num)
bda7bad6 716{
75ba1d07
JP
717 int len;
718
719 if (m->count + 3 >= m->size) /* we'll write 2 bytes at least */
720 goto overflow;
721
722 len = strlen(delimiter);
723 if (m->count + len >= m->size)
724 goto overflow;
725
726 memcpy(m->buf + m->count, delimiter, len);
727 m->count += len;
728
729 if (m->count + 2 >= m->size)
730 goto overflow;
731
bda7bad6 732 if (num < 0) {
75ba1d07 733 m->buf[m->count++] = '-';
bda7bad6 734 num = -num;
bda7bad6 735 }
75ba1d07
JP
736
737 if (num < 10) {
738 m->buf[m->count++] = num + '0';
739 return;
740 }
741
742 len = num_to_str(m->buf + m->count, m->size - m->count, num);
743 if (!len)
744 goto overflow;
745
746 m->count += len;
747 return;
748
749overflow:
750 seq_set_overflow(m);
bda7bad6
KH
751}
752EXPORT_SYMBOL(seq_put_decimal_ll);
753
0b923606
PO
754/**
755 * seq_write - write arbitrary data to buffer
756 * @seq: seq_file identifying the buffer to which data should be written
757 * @data: data address
758 * @len: number of bytes
759 *
760 * Return 0 on success, non-zero otherwise.
761 */
762int seq_write(struct seq_file *seq, const void *data, size_t len)
763{
764 if (seq->count + len < seq->size) {
765 memcpy(seq->buf + seq->count, data, len);
766 seq->count += len;
767 return 0;
768 }
e075f591 769 seq_set_overflow(seq);
0b923606
PO
770 return -1;
771}
772EXPORT_SYMBOL(seq_write);
773
839cc2a9
TH
774/**
775 * seq_pad - write padding spaces to buffer
776 * @m: seq_file identifying the buffer to which data should be written
777 * @c: the byte to append after padding if non-zero
778 */
779void seq_pad(struct seq_file *m, char c)
780{
781 int size = m->pad_until - m->count;
782 if (size > 0)
783 seq_printf(m, "%*s", size, "");
784 if (c)
785 seq_putc(m, c);
786}
787EXPORT_SYMBOL(seq_pad);
788
37607102
AS
789/* A complete analogue of print_hex_dump() */
790void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
791 int rowsize, int groupsize, const void *buf, size_t len,
792 bool ascii)
793{
794 const u8 *ptr = buf;
795 int i, linelen, remaining = len;
8b91a318
AS
796 char *buffer;
797 size_t size;
37607102
AS
798 int ret;
799
800 if (rowsize != 16 && rowsize != 32)
801 rowsize = 16;
802
803 for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) {
804 linelen = min(remaining, rowsize);
805 remaining -= rowsize;
806
807 switch (prefix_type) {
808 case DUMP_PREFIX_ADDRESS:
809 seq_printf(m, "%s%p: ", prefix_str, ptr + i);
810 break;
811 case DUMP_PREFIX_OFFSET:
812 seq_printf(m, "%s%.8x: ", prefix_str, i);
813 break;
814 default:
815 seq_printf(m, "%s", prefix_str);
816 break;
817 }
818
8b91a318 819 size = seq_get_buf(m, &buffer);
37607102 820 ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
8b91a318
AS
821 buffer, size, ascii);
822 seq_commit(m, ret < size ? ret : -1);
823
824 seq_putc(m, '\n');
37607102
AS
825 }
826}
827EXPORT_SYMBOL(seq_hex_dump);
828
bcf67e16
PE
829struct list_head *seq_list_start(struct list_head *head, loff_t pos)
830{
831 struct list_head *lh;
832
833 list_for_each(lh, head)
834 if (pos-- == 0)
835 return lh;
836
837 return NULL;
838}
bcf67e16
PE
839EXPORT_SYMBOL(seq_list_start);
840
841struct list_head *seq_list_start_head(struct list_head *head, loff_t pos)
842{
843 if (!pos)
844 return head;
845
846 return seq_list_start(head, pos - 1);
847}
bcf67e16
PE
848EXPORT_SYMBOL(seq_list_start_head);
849
850struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos)
851{
852 struct list_head *lh;
853
854 lh = ((struct list_head *)v)->next;
855 ++*ppos;
856 return lh == head ? NULL : lh;
857}
bcf67e16 858EXPORT_SYMBOL(seq_list_next);
66655de6
LZ
859
860/**
861 * seq_hlist_start - start an iteration of a hlist
862 * @head: the head of the hlist
863 * @pos: the start position of the sequence
864 *
865 * Called at seq_file->op->start().
866 */
867struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos)
868{
869 struct hlist_node *node;
870
871 hlist_for_each(node, head)
872 if (pos-- == 0)
873 return node;
874 return NULL;
875}
876EXPORT_SYMBOL(seq_hlist_start);
877
878/**
879 * seq_hlist_start_head - start an iteration of a hlist
880 * @head: the head of the hlist
881 * @pos: the start position of the sequence
882 *
883 * Called at seq_file->op->start(). Call this function if you want to
884 * print a header at the top of the output.
885 */
886struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos)
887{
888 if (!pos)
889 return SEQ_START_TOKEN;
890
891 return seq_hlist_start(head, pos - 1);
892}
893EXPORT_SYMBOL(seq_hlist_start_head);
894
895/**
896 * seq_hlist_next - move to the next position of the hlist
897 * @v: the current iterator
898 * @head: the head of the hlist
138860b9 899 * @ppos: the current position
66655de6
LZ
900 *
901 * Called at seq_file->op->next().
902 */
903struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
904 loff_t *ppos)
905{
906 struct hlist_node *node = v;
907
908 ++*ppos;
909 if (v == SEQ_START_TOKEN)
910 return head->first;
911 else
912 return node->next;
913}
914EXPORT_SYMBOL(seq_hlist_next);
1cc52327 915
916/**
917 * seq_hlist_start_rcu - start an iteration of a hlist protected by RCU
918 * @head: the head of the hlist
919 * @pos: the start position of the sequence
920 *
921 * Called at seq_file->op->start().
922 *
923 * This list-traversal primitive may safely run concurrently with
924 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
925 * as long as the traversal is guarded by rcu_read_lock().
926 */
927struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
928 loff_t pos)
929{
930 struct hlist_node *node;
931
932 __hlist_for_each_rcu(node, head)
933 if (pos-- == 0)
934 return node;
935 return NULL;
936}
937EXPORT_SYMBOL(seq_hlist_start_rcu);
938
939/**
940 * seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU
941 * @head: the head of the hlist
942 * @pos: the start position of the sequence
943 *
944 * Called at seq_file->op->start(). Call this function if you want to
945 * print a header at the top of the output.
946 *
947 * This list-traversal primitive may safely run concurrently with
948 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
949 * as long as the traversal is guarded by rcu_read_lock().
950 */
951struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
952 loff_t pos)
953{
954 if (!pos)
955 return SEQ_START_TOKEN;
956
957 return seq_hlist_start_rcu(head, pos - 1);
958}
959EXPORT_SYMBOL(seq_hlist_start_head_rcu);
960
961/**
962 * seq_hlist_next_rcu - move to the next position of the hlist protected by RCU
963 * @v: the current iterator
964 * @head: the head of the hlist
138860b9 965 * @ppos: the current position
1cc52327 966 *
967 * Called at seq_file->op->next().
968 *
969 * This list-traversal primitive may safely run concurrently with
970 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
971 * as long as the traversal is guarded by rcu_read_lock().
972 */
973struct hlist_node *seq_hlist_next_rcu(void *v,
974 struct hlist_head *head,
975 loff_t *ppos)
976{
977 struct hlist_node *node = v;
978
979 ++*ppos;
980 if (v == SEQ_START_TOKEN)
981 return rcu_dereference(head->first);
982 else
983 return rcu_dereference(node->next);
984}
985EXPORT_SYMBOL(seq_hlist_next_rcu);
0bc77381
JL
986
987/**
988 * seq_hlist_start_precpu - start an iteration of a percpu hlist array
989 * @head: pointer to percpu array of struct hlist_heads
990 * @cpu: pointer to cpu "cursor"
991 * @pos: start position of sequence
992 *
993 * Called at seq_file->op->start().
994 */
995struct hlist_node *
996seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos)
997{
998 struct hlist_node *node;
999
1000 for_each_possible_cpu(*cpu) {
1001 hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
1002 if (pos-- == 0)
1003 return node;
1004 }
1005 }
1006 return NULL;
1007}
1008EXPORT_SYMBOL(seq_hlist_start_percpu);
1009
1010/**
1011 * seq_hlist_next_percpu - move to the next position of the percpu hlist array
1012 * @v: pointer to current hlist_node
1013 * @head: pointer to percpu array of struct hlist_heads
1014 * @cpu: pointer to cpu "cursor"
1015 * @pos: start position of sequence
1016 *
1017 * Called at seq_file->op->next().
1018 */
1019struct hlist_node *
1020seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
1021 int *cpu, loff_t *pos)
1022{
1023 struct hlist_node *node = v;
1024
1025 ++*pos;
1026
1027 if (node->next)
1028 return node->next;
1029
1030 for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
1031 *cpu = cpumask_next(*cpu, cpu_possible_mask)) {
1032 struct hlist_head *bucket = per_cpu_ptr(head, *cpu);
1033
1034 if (!hlist_empty(bucket))
1035 return bucket->first;
1036 }
1037 return NULL;
1038}
1039EXPORT_SYMBOL(seq_hlist_next_percpu);