1// SPDX-License-Identifier: GPL-2.0
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/cache.h>
10#include <linux/fs.h>
11#include <linux/export.h>
12#include <linux/seq_file.h>
13#include <linux/vmalloc.h>
14#include <linux/slab.h>
15#include <linux/cred.h>
16#include <linux/mm.h>
17#include <linux/printk.h>
18#include <linux/string_helpers.h>
19
20#include <linux/uaccess.h>
21#include <asm/page.h>
22
23static struct kmem_cache *seq_file_cache __ro_after_init;
24
25static void seq_set_overflow(struct seq_file *m)
26{
27 m->count = m->size;
28}
29
30static void *seq_buf_alloc(unsigned long size)
31{
32 return kvmalloc(size, GFP_KERNEL_ACCOUNT);
33}
34
35/**
36 * seq_open - initialize sequential file
37 * @file: file we initialize
38 * @op: method table describing the sequence
39 *
40 * seq_open() sets @file, associating it with a sequence described
41 * by @op. @op->start() sets the iterator up and returns the first
42 * element of sequence. @op->stop() shuts it down. @op->next()
43 * returns the next element of sequence. @op->show() prints element
44 * into the buffer. In case of error ->start() and ->next() return
45 * ERR_PTR(error). In the end of sequence they return %NULL. ->show()
46 * returns 0 in case of success and negative number in case of error.
47 * Returning SEQ_SKIP means "discard this element and move on".
48 * Note: seq_open() will allocate a struct seq_file and store its
49 * pointer in @file->private_data. This pointer should not be modified.
50 */
51int seq_open(struct file *file, const struct seq_operations *op)
52{
53 struct seq_file *p;
54
55 WARN_ON(file->private_data);
56
57 p = kmem_cache_zalloc(seq_file_cache, GFP_KERNEL);
58 if (!p)
59 return -ENOMEM;
60
61 file->private_data = p;
62
63 mutex_init(&p->lock);
64 p->op = op;
65
66 // No refcounting: the lifetime of 'p' is constrained
67 // to the lifetime of the file.
68 p->file = file;
69
70 /*
71 * Wrappers around seq_open(e.g. swaps_open) need to be
72 * aware of this. If they set f_version themselves, they
73 * should call seq_open first and then set f_version.
74 */
75 file->f_version = 0;
76
77 /*
78 * seq_files support lseek() and pread(). They do not implement
79 * write() at all, but we clear FMODE_PWRITE here for historical
80 * reasons.
81 *
82 * If a client of seq_files a) implements file.write() and b) wishes to
83 * support pwrite() then that client will need to implement its own
84 * file.open() which calls seq_open() and then sets FMODE_PWRITE.
85 */
86 file->f_mode &= ~FMODE_PWRITE;
87 return 0;
88}
89EXPORT_SYMBOL(seq_open);
90
91static int traverse(struct seq_file *m, loff_t offset)
92{
93 loff_t pos = 0;
94 int error = 0;
95 void *p;
96
97 m->version = 0;
98 m->index = 0;
99 m->count = m->from = 0;
100 if (!offset)
101 return 0;
102
103 if (!m->buf) {
104 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
105 if (!m->buf)
106 return -ENOMEM;
107 }
108 p = m->op->start(m, &m->index);
109 while (p) {
110 error = PTR_ERR(p);
111 if (IS_ERR(p))
112 break;
113 error = m->op->show(m, p);
114 if (error < 0)
115 break;
116 if (unlikely(error)) {
117 error = 0;
118 m->count = 0;
119 }
120 if (seq_has_overflowed(m))
121 goto Eoverflow;
122 if (pos + m->count > offset) {
123 m->from = offset - pos;
124 m->count -= m->from;
125 break;
126 }
127 pos += m->count;
128 m->count = 0;
129 p = m->op->next(m, p, &m->index);
130 if (pos == offset)
131 break;
132 }
133 m->op->stop(m, p);
134 return error;
135
136Eoverflow:
137 m->op->stop(m, p);
138 kvfree(m->buf);
139 m->count = 0;
140 m->buf = seq_buf_alloc(m->size <<= 1);
141 return !m->buf ? -ENOMEM : -EAGAIN;
142}
143
144/**
145 * seq_read - ->read() method for sequential files.
146 * @file: the file to read from
147 * @buf: the buffer to read to
148 * @size: the maximum number of bytes to read
149 * @ppos: the current position in the file
150 *
151 * Ready-made ->f_op->read()
152 */
153ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
154{
155 struct seq_file *m = file->private_data;
156 size_t copied = 0;
157 size_t n;
158 void *p;
159 int err = 0;
160
161 mutex_lock(&m->lock);
162
163 /*
164 * seq_file->op->..m_start/m_stop/m_next may do special actions
165 * or optimisations based on the file->f_version, so we want to
166 * pass the file->f_version to those methods.
167 *
168 * seq_file->version is just copy of f_version, and seq_file
169 * methods can treat it simply as file version.
170 * It is copied in first and copied out after all operations.
171 * It is convenient to have it as part of structure to avoid the
172 * need of passing another argument to all the seq_file methods.
173 */
174 m->version = file->f_version;
175
176 /*
177 * if request is to read from zero offset, reset iterator to first
178 * record as it might have been already advanced by previous requests
179 */
180 if (*ppos == 0) {
181 m->index = 0;
182 m->version = 0;
183 m->count = 0;
184 }
185
186 /* Don't assume *ppos is where we left it */
187 if (unlikely(*ppos != m->read_pos)) {
188 while ((err = traverse(m, *ppos)) == -EAGAIN)
189 ;
190 if (err) {
191 /* With prejudice... */
192 m->read_pos = 0;
193 m->version = 0;
194 m->index = 0;
195 m->count = 0;
196 goto Done;
197 } else {
198 m->read_pos = *ppos;
199 }
200 }
201
202 /* grab buffer if we didn't have one */
203 if (!m->buf) {
204 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
205 if (!m->buf)
206 goto Enomem;
207 }
208 /* if not empty - flush it first */
209 if (m->count) {
210 n = min(m->count, size);
211 err = copy_to_user(buf, m->buf + m->from, n);
212 if (err)
213 goto Efault;
214 m->count -= n;
215 m->from += n;
216 size -= n;
217 buf += n;
218 copied += n;
219 if (!size)
220 goto Done;
221 }
222 /* we need at least one record in buffer */
223 m->from = 0;
224 p = m->op->start(m, &m->index);
225 while (1) {
226 err = PTR_ERR(p);
227 if (!p || IS_ERR(p))
228 break;
229 err = m->op->show(m, p);
230 if (err < 0)
231 break;
232 if (unlikely(err))
233 m->count = 0;
234 if (unlikely(!m->count)) {
235 p = m->op->next(m, p, &m->index);
236 continue;
237 }
238 if (m->count < m->size)
239 goto Fill;
240 m->op->stop(m, p);
241 kvfree(m->buf);
242 m->count = 0;
243 m->buf = seq_buf_alloc(m->size <<= 1);
244 if (!m->buf)
245 goto Enomem;
246 m->version = 0;
247 p = m->op->start(m, &m->index);
248 }
249 m->op->stop(m, p);
250 m->count = 0;
251 goto Done;
252Fill:
253 /* they want more? let's try to get some more */
254 while (1) {
255 size_t offs = m->count;
256 loff_t pos = m->index;
257
258 p = m->op->next(m, p, &m->index);
259 if (pos == m->index)
260 /* Buggy ->next function */
261 m->index++;
262 if (!p || IS_ERR(p)) {
263 err = PTR_ERR(p);
264 break;
265 }
266 if (m->count >= size)
267 break;
268 err = m->op->show(m, p);
269 if (seq_has_overflowed(m) || err) {
270 m->count = offs;
271 if (likely(err <= 0))
272 break;
273 }
274 }
275 m->op->stop(m, p);
276 n = min(m->count, size);
277 err = copy_to_user(buf, m->buf, n);
278 if (err)
279 goto Efault;
280 copied += n;
281 m->count -= n;
282 m->from = n;
283Done:
284 if (!copied)
285 copied = err;
286 else {
287 *ppos += copied;
288 m->read_pos += copied;
289 }
290 file->f_version = m->version;
291 mutex_unlock(&m->lock);
292 return copied;
293Enomem:
294 err = -ENOMEM;
295 goto Done;
296Efault:
297 err = -EFAULT;
298 goto Done;
299}
300EXPORT_SYMBOL(seq_read);
301
302/**
303 * seq_lseek - ->llseek() method for sequential files.
304 * @file: the file in question
305 * @offset: new position
306 * @whence: 0 for absolute, 1 for relative position
307 *
308 * Ready-made ->f_op->llseek()
309 */
310loff_t seq_lseek(struct file *file, loff_t offset, int whence)
311{
312 struct seq_file *m = file->private_data;
313 loff_t retval = -EINVAL;
314
315 mutex_lock(&m->lock);
316 m->version = file->f_version;
317 switch (whence) {
318 case SEEK_CUR:
319 offset += file->f_pos;
320 case SEEK_SET:
321 if (offset < 0)
322 break;
323 retval = offset;
324 if (offset != m->read_pos) {
325 while ((retval = traverse(m, offset)) == -EAGAIN)
326 ;
327 if (retval) {
328 /* with extreme prejudice... */
329 file->f_pos = 0;
330 m->read_pos = 0;
331 m->version = 0;
332 m->index = 0;
333 m->count = 0;
334 } else {
335 m->read_pos = offset;
336 retval = file->f_pos = offset;
337 }
338 } else {
339 file->f_pos = offset;
340 }
341 }
342 file->f_version = m->version;
343 mutex_unlock(&m->lock);
344 return retval;
345}
346EXPORT_SYMBOL(seq_lseek);
347
348/**
349 * seq_release - free the structures associated with sequential file.
350 * @file: file in question
351 * @inode: its inode
352 *
353 * Frees the structures associated with sequential file; can be used
354 * as ->f_op->release() if you don't have private data to destroy.
355 */
356int seq_release(struct inode *inode, struct file *file)
357{
358 struct seq_file *m = file->private_data;
359 kvfree(m->buf);
360 kmem_cache_free(seq_file_cache, m);
361 return 0;
362}
363EXPORT_SYMBOL(seq_release);
364
365/**
366 * seq_escape - print string into buffer, escaping some characters
367 * @m: target buffer
368 * @s: string
369 * @esc: set of characters that need escaping
370 *
371 * Puts string into buffer, replacing each occurrence of character from
372 * @esc with usual octal escape.
373 * Use seq_has_overflowed() to check for errors.
374 */
375void seq_escape(struct seq_file *m, const char *s, const char *esc)
376{
377 char *buf;
378 size_t size = seq_get_buf(m, &buf);
379 int ret;
380
381 ret = string_escape_str(s, buf, size, ESCAPE_OCTAL, esc);
382 seq_commit(m, ret < size ? ret : -1);
383}
384EXPORT_SYMBOL(seq_escape);
385
386void seq_vprintf(struct seq_file *m, const char *f, va_list args)
387{
388 int len;
389
390 if (m->count < m->size) {
391 len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
392 if (m->count + len < m->size) {
393 m->count += len;
394 return;
395 }
396 }
397 seq_set_overflow(m);
398}
399EXPORT_SYMBOL(seq_vprintf);
400
401void seq_printf(struct seq_file *m, const char *f, ...)
402{
403 va_list args;
404
405 va_start(args, f);
406 seq_vprintf(m, f, args);
407 va_end(args);
408}
409EXPORT_SYMBOL(seq_printf);
410
411/**
412 * mangle_path - mangle and copy path to buffer beginning
413 * @s: buffer start
414 * @p: beginning of path in above buffer
415 * @esc: set of characters that need escaping
416 *
417 * Copy the path from @p to @s, replacing each occurrence of character from
418 * @esc with usual octal escape.
419 * Returns pointer past last written character in @s, or NULL in case of
420 * failure.
421 */
422char *mangle_path(char *s, const char *p, const char *esc)
423{
424 while (s <= p) {
425 char c = *p++;
426 if (!c) {
427 return s;
428 } else if (!strchr(esc, c)) {
429 *s++ = c;
430 } else if (s + 4 > p) {
431 break;
432 } else {
433 *s++ = '\\';
434 *s++ = '0' + ((c & 0300) >> 6);
435 *s++ = '0' + ((c & 070) >> 3);
436 *s++ = '0' + (c & 07);
437 }
438 }
439 return NULL;
440}
441EXPORT_SYMBOL(mangle_path);
442
443/**
444 * seq_path - seq_file interface to print a pathname
445 * @m: the seq_file handle
446 * @path: the struct path to print
447 * @esc: set of characters to escape in the output
448 *
449 * return the absolute path of 'path', as represented by the
450 * dentry / mnt pair in the path parameter.
451 */
452int seq_path(struct seq_file *m, const struct path *path, const char *esc)
453{
454 char *buf;
455 size_t size = seq_get_buf(m, &buf);
456 int res = -1;
457
458 if (size) {
459 char *p = d_path(path, buf, size);
460 if (!IS_ERR(p)) {
461 char *end = mangle_path(buf, p, esc);
462 if (end)
463 res = end - buf;
464 }
465 }
466 seq_commit(m, res);
467
468 return res;
469}
470EXPORT_SYMBOL(seq_path);
471
472/**
473 * seq_file_path - seq_file interface to print a pathname of a file
474 * @m: the seq_file handle
475 * @file: the struct file to print
476 * @esc: set of characters to escape in the output
477 *
478 * return the absolute path to the file.
479 */
480int seq_file_path(struct seq_file *m, struct file *file, const char *esc)
481{
482 return seq_path(m, &file->f_path, esc);
483}
484EXPORT_SYMBOL(seq_file_path);
485
486/*
487 * Same as seq_path, but relative to supplied root.
488 */
489int seq_path_root(struct seq_file *m, const struct path *path,
490 const struct path *root, const char *esc)
491{
492 char *buf;
493 size_t size = seq_get_buf(m, &buf);
494 int res = -ENAMETOOLONG;
495
496 if (size) {
497 char *p;
498
499 p = __d_path(path, root, buf, size);
500 if (!p)
501 return SEQ_SKIP;
502 res = PTR_ERR(p);
503 if (!IS_ERR(p)) {
504 char *end = mangle_path(buf, p, esc);
505 if (end)
506 res = end - buf;
507 else
508 res = -ENAMETOOLONG;
509 }
510 }
511 seq_commit(m, res);
512
513 return res < 0 && res != -ENAMETOOLONG ? res : 0;
514}
515
516/*
517 * returns the path of the 'dentry' from the root of its filesystem.
518 */
519int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc)
520{
521 char *buf;
522 size_t size = seq_get_buf(m, &buf);
523 int res = -1;
524
525 if (size) {
526 char *p = dentry_path(dentry, buf, size);
527 if (!IS_ERR(p)) {
528 char *end = mangle_path(buf, p, esc);
529 if (end)
530 res = end - buf;
531 }
532 }
533 seq_commit(m, res);
534
535 return res;
536}
537EXPORT_SYMBOL(seq_dentry);
538
539static void *single_start(struct seq_file *p, loff_t *pos)
540{
541 return NULL + (*pos == 0);
542}
543
544static void *single_next(struct seq_file *p, void *v, loff_t *pos)
545{
546 ++*pos;
547 return NULL;
548}
549
550static void single_stop(struct seq_file *p, void *v)
551{
552}
553
554int single_open(struct file *file, int (*show)(struct seq_file *, void *),
555 void *data)
556{
557 struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL_ACCOUNT);
558 int res = -ENOMEM;
559
560 if (op) {
561 op->start = single_start;
562 op->next = single_next;
563 op->stop = single_stop;
564 op->show = show;
565 res = seq_open(file, op);
566 if (!res)
567 ((struct seq_file *)file->private_data)->private = data;
568 else
569 kfree(op);
570 }
571 return res;
572}
573EXPORT_SYMBOL(single_open);
574
575int single_open_size(struct file *file, int (*show)(struct seq_file *, void *),
576 void *data, size_t size)
577{
578 char *buf = seq_buf_alloc(size);
579 int ret;
580 if (!buf)
581 return -ENOMEM;
582 ret = single_open(file, show, data);
583 if (ret) {
584 kvfree(buf);
585 return ret;
586 }
587 ((struct seq_file *)file->private_data)->buf = buf;
588 ((struct seq_file *)file->private_data)->size = size;
589 return 0;
590}
591EXPORT_SYMBOL(single_open_size);
592
593int single_release(struct inode *inode, struct file *file)
594{
595 const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
596 int res = seq_release(inode, file);
597 kfree(op);
598 return res;
599}
600EXPORT_SYMBOL(single_release);
601
602int seq_release_private(struct inode *inode, struct file *file)
603{
604 struct seq_file *seq = file->private_data;
605
606 kfree(seq->private);
607 seq->private = NULL;
608 return seq_release(inode, file);
609}
610EXPORT_SYMBOL(seq_release_private);
611
612void *__seq_open_private(struct file *f, const struct seq_operations *ops,
613 int psize)
614{
615 int rc;
616 void *private;
617 struct seq_file *seq;
618
619 private = kzalloc(psize, GFP_KERNEL_ACCOUNT);
620 if (private == NULL)
621 goto out;
622
623 rc = seq_open(f, ops);
624 if (rc < 0)
625 goto out_free;
626
627 seq = f->private_data;
628 seq->private = private;
629 return private;
630
631out_free:
632 kfree(private);
633out:
634 return NULL;
635}
636EXPORT_SYMBOL(__seq_open_private);
637
638int seq_open_private(struct file *filp, const struct seq_operations *ops,
639 int psize)
640{
641 return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;
642}
643EXPORT_SYMBOL(seq_open_private);
644
645void seq_putc(struct seq_file *m, char c)
646{
647 if (m->count >= m->size)
648 return;
649
650 m->buf[m->count++] = c;
651}
652EXPORT_SYMBOL(seq_putc);
653
654void seq_puts(struct seq_file *m, const char *s)
655{
656 int len = strlen(s);
657
658 if (m->count + len >= m->size) {
659 seq_set_overflow(m);
660 return;
661 }
662 memcpy(m->buf + m->count, s, len);
663 m->count += len;
664}
665EXPORT_SYMBOL(seq_puts);
666
667/**
668 * A helper routine for putting decimal numbers without rich format of printf().
669 * only 'unsigned long long' is supported.
670 * @m: seq_file identifying the buffer to which data should be written
671 * @delimiter: a string which is printed before the number
672 * @num: the number
673 * @width: a minimum field width
674 *
675 * This routine will put strlen(delimiter) + number into seq_filed.
676 * This routine is very quick when you show lots of numbers.
677 * In usual cases, it will be better to use seq_printf(). It's easier to read.
678 */
679void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
680 unsigned long long num, unsigned int width)
681{
682 int len;
683
684 if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */
685 goto overflow;
686
687 if (delimiter && delimiter[0]) {
688 if (delimiter[1] == 0)
689 seq_putc(m, delimiter[0]);
690 else
691 seq_puts(m, delimiter);
692 }
693
694 if (!width)
695 width = 1;
696
697 if (m->count + width >= m->size)
698 goto overflow;
699
700 len = num_to_str(m->buf + m->count, m->size - m->count, num, width);
701 if (!len)
702 goto overflow;
703
704 m->count += len;
705 return;
706
707overflow:
708 seq_set_overflow(m);
709}
710
711void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
712 unsigned long long num)
713{
714 return seq_put_decimal_ull_width(m, delimiter, num, 0);
715}
716EXPORT_SYMBOL(seq_put_decimal_ull);
717
718/**
719 * seq_put_hex_ll - put a number in hexadecimal notation
720 * @m: seq_file identifying the buffer to which data should be written
721 * @delimiter: a string which is printed before the number
722 * @v: the number
723 * @width: a minimum field width
724 *
725 * seq_put_hex_ll(m, "", v, 8) is equal to seq_printf(m, "%08llx", v)
726 *
727 * This routine is very quick when you show lots of numbers.
728 * In usual cases, it will be better to use seq_printf(). It's easier to read.
729 */
730void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
731 unsigned long long v, unsigned int width)
732{
733 unsigned int len;
734 int i;
735
736 if (delimiter && delimiter[0]) {
737 if (delimiter[1] == 0)
738 seq_putc(m, delimiter[0]);
739 else
740 seq_puts(m, delimiter);
741 }
742
743 /* If x is 0, the result of __builtin_clzll is undefined */
744 if (v == 0)
745 len = 1;
746 else
747 len = (sizeof(v) * 8 - __builtin_clzll(v) + 3) / 4;
748
749 if (len < width)
750 len = width;
751
752 if (m->count + len > m->size) {
753 seq_set_overflow(m);
754 return;
755 }
756
757 for (i = len - 1; i >= 0; i--) {
758 m->buf[m->count + i] = hex_asc[0xf & v];
759 v = v >> 4;
760 }
761 m->count += len;
762}
763
764void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num)
765{
766 int len;
767
768 if (m->count + 3 >= m->size) /* we'll write 2 bytes at least */
769 goto overflow;
770
771 if (delimiter && delimiter[0]) {
772 if (delimiter[1] == 0)
773 seq_putc(m, delimiter[0]);
774 else
775 seq_puts(m, delimiter);
776 }
777
778 if (m->count + 2 >= m->size)
779 goto overflow;
780
781 if (num < 0) {
782 m->buf[m->count++] = '-';
783 num = -num;
784 }
785
786 if (num < 10) {
787 m->buf[m->count++] = num + '0';
788 return;
789 }
790
791 len = num_to_str(m->buf + m->count, m->size - m->count, num, 0);
792 if (!len)
793 goto overflow;
794
795 m->count += len;
796 return;
797
798overflow:
799 seq_set_overflow(m);
800}
801EXPORT_SYMBOL(seq_put_decimal_ll);
802
803/**
804 * seq_write - write arbitrary data to buffer
805 * @seq: seq_file identifying the buffer to which data should be written
806 * @data: data address
807 * @len: number of bytes
808 *
809 * Return 0 on success, non-zero otherwise.
810 */
811int seq_write(struct seq_file *seq, const void *data, size_t len)
812{
813 if (seq->count + len < seq->size) {
814 memcpy(seq->buf + seq->count, data, len);
815 seq->count += len;
816 return 0;
817 }
818 seq_set_overflow(seq);
819 return -1;
820}
821EXPORT_SYMBOL(seq_write);
822
823/**
824 * seq_pad - write padding spaces to buffer
825 * @m: seq_file identifying the buffer to which data should be written
826 * @c: the byte to append after padding if non-zero
827 */
828void seq_pad(struct seq_file *m, char c)
829{
830 int size = m->pad_until - m->count;
831 if (size > 0) {
832 if (size + m->count > m->size) {
833 seq_set_overflow(m);
834 return;
835 }
836 memset(m->buf + m->count, ' ', size);
837 m->count += size;
838 }
839 if (c)
840 seq_putc(m, c);
841}
842EXPORT_SYMBOL(seq_pad);
843
844/* A complete analogue of print_hex_dump() */
845void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
846 int rowsize, int groupsize, const void *buf, size_t len,
847 bool ascii)
848{
849 const u8 *ptr = buf;
850 int i, linelen, remaining = len;
851 char *buffer;
852 size_t size;
853 int ret;
854
855 if (rowsize != 16 && rowsize != 32)
856 rowsize = 16;
857
858 for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) {
859 linelen = min(remaining, rowsize);
860 remaining -= rowsize;
861
862 switch (prefix_type) {
863 case DUMP_PREFIX_ADDRESS:
864 seq_printf(m, "%s%p: ", prefix_str, ptr + i);
865 break;
866 case DUMP_PREFIX_OFFSET:
867 seq_printf(m, "%s%.8x: ", prefix_str, i);
868 break;
869 default:
870 seq_printf(m, "%s", prefix_str);
871 break;
872 }
873
874 size = seq_get_buf(m, &buffer);
875 ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
876 buffer, size, ascii);
877 seq_commit(m, ret < size ? ret : -1);
878
879 seq_putc(m, '\n');
880 }
881}
882EXPORT_SYMBOL(seq_hex_dump);
883
884struct list_head *seq_list_start(struct list_head *head, loff_t pos)
885{
886 struct list_head *lh;
887
888 list_for_each(lh, head)
889 if (pos-- == 0)
890 return lh;
891
892 return NULL;
893}
894EXPORT_SYMBOL(seq_list_start);
895
896struct list_head *seq_list_start_head(struct list_head *head, loff_t pos)
897{
898 if (!pos)
899 return head;
900
901 return seq_list_start(head, pos - 1);
902}
903EXPORT_SYMBOL(seq_list_start_head);
904
905struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos)
906{
907 struct list_head *lh;
908
909 lh = ((struct list_head *)v)->next;
910 ++*ppos;
911 return lh == head ? NULL : lh;
912}
913EXPORT_SYMBOL(seq_list_next);
914
915/**
916 * seq_hlist_start - start an iteration of a hlist
917 * @head: the head of the hlist
918 * @pos: the start position of the sequence
919 *
920 * Called at seq_file->op->start().
921 */
922struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos)
923{
924 struct hlist_node *node;
925
926 hlist_for_each(node, head)
927 if (pos-- == 0)
928 return node;
929 return NULL;
930}
931EXPORT_SYMBOL(seq_hlist_start);
932
933/**
934 * seq_hlist_start_head - start an iteration of a hlist
935 * @head: the head of the hlist
936 * @pos: the start position of the sequence
937 *
938 * Called at seq_file->op->start(). Call this function if you want to
939 * print a header at the top of the output.
940 */
941struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos)
942{
943 if (!pos)
944 return SEQ_START_TOKEN;
945
946 return seq_hlist_start(head, pos - 1);
947}
948EXPORT_SYMBOL(seq_hlist_start_head);
949
950/**
951 * seq_hlist_next - move to the next position of the hlist
952 * @v: the current iterator
953 * @head: the head of the hlist
954 * @ppos: the current position
955 *
956 * Called at seq_file->op->next().
957 */
958struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
959 loff_t *ppos)
960{
961 struct hlist_node *node = v;
962
963 ++*ppos;
964 if (v == SEQ_START_TOKEN)
965 return head->first;
966 else
967 return node->next;
968}
969EXPORT_SYMBOL(seq_hlist_next);
970
971/**
972 * seq_hlist_start_rcu - start an iteration of a hlist protected by RCU
973 * @head: the head of the hlist
974 * @pos: the start position of the sequence
975 *
976 * Called at seq_file->op->start().
977 *
978 * This list-traversal primitive may safely run concurrently with
979 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
980 * as long as the traversal is guarded by rcu_read_lock().
981 */
982struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
983 loff_t pos)
984{
985 struct hlist_node *node;
986
987 __hlist_for_each_rcu(node, head)
988 if (pos-- == 0)
989 return node;
990 return NULL;
991}
992EXPORT_SYMBOL(seq_hlist_start_rcu);
993
994/**
995 * seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU
996 * @head: the head of the hlist
997 * @pos: the start position of the sequence
998 *
999 * Called at seq_file->op->start(). Call this function if you want to
1000 * print a header at the top of the output.
1001 *
1002 * This list-traversal primitive may safely run concurrently with
1003 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1004 * as long as the traversal is guarded by rcu_read_lock().
1005 */
1006struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
1007 loff_t pos)
1008{
1009 if (!pos)
1010 return SEQ_START_TOKEN;
1011
1012 return seq_hlist_start_rcu(head, pos - 1);
1013}
1014EXPORT_SYMBOL(seq_hlist_start_head_rcu);
1015
1016/**
1017 * seq_hlist_next_rcu - move to the next position of the hlist protected by RCU
1018 * @v: the current iterator
1019 * @head: the head of the hlist
1020 * @ppos: the current position
1021 *
1022 * Called at seq_file->op->next().
1023 *
1024 * This list-traversal primitive may safely run concurrently with
1025 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1026 * as long as the traversal is guarded by rcu_read_lock().
1027 */
1028struct hlist_node *seq_hlist_next_rcu(void *v,
1029 struct hlist_head *head,
1030 loff_t *ppos)
1031{
1032 struct hlist_node *node = v;
1033
1034 ++*ppos;
1035 if (v == SEQ_START_TOKEN)
1036 return rcu_dereference(head->first);
1037 else
1038 return rcu_dereference(node->next);
1039}
1040EXPORT_SYMBOL(seq_hlist_next_rcu);
1041
1042/**
1043 * seq_hlist_start_precpu - start an iteration of a percpu hlist array
1044 * @head: pointer to percpu array of struct hlist_heads
1045 * @cpu: pointer to cpu "cursor"
1046 * @pos: start position of sequence
1047 *
1048 * Called at seq_file->op->start().
1049 */
1050struct hlist_node *
1051seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos)
1052{
1053 struct hlist_node *node;
1054
1055 for_each_possible_cpu(*cpu) {
1056 hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
1057 if (pos-- == 0)
1058 return node;
1059 }
1060 }
1061 return NULL;
1062}
1063EXPORT_SYMBOL(seq_hlist_start_percpu);
1064
1065/**
1066 * seq_hlist_next_percpu - move to the next position of the percpu hlist array
1067 * @v: pointer to current hlist_node
1068 * @head: pointer to percpu array of struct hlist_heads
1069 * @cpu: pointer to cpu "cursor"
1070 * @pos: start position of sequence
1071 *
1072 * Called at seq_file->op->next().
1073 */
1074struct hlist_node *
1075seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
1076 int *cpu, loff_t *pos)
1077{
1078 struct hlist_node *node = v;
1079
1080 ++*pos;
1081
1082 if (node->next)
1083 return node->next;
1084
1085 for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
1086 *cpu = cpumask_next(*cpu, cpu_possible_mask)) {
1087 struct hlist_head *bucket = per_cpu_ptr(head, *cpu);
1088
1089 if (!hlist_empty(bucket))
1090 return bucket->first;
1091 }
1092 return NULL;
1093}
1094EXPORT_SYMBOL(seq_hlist_next_percpu);
1095
1096void __init seq_file_init(void)
1097{
1098 seq_file_cache = KMEM_CACHE(seq_file, SLAB_ACCOUNT|SLAB_PANIC);
1099}
1100