1
2
3
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5
6
7
8#include <linux/fs.h>
9#include <linux/export.h>
10#include <linux/seq_file.h>
11#include <linux/vmalloc.h>
12#include <linux/slab.h>
13#include <linux/cred.h>
14#include <linux/mm.h>
15#include <linux/printk.h>
16#include <linux/string_helpers.h>
17
18#include <asm/uaccess.h>
19#include <asm/page.h>
20
21static void seq_set_overflow(struct seq_file *m)
22{
23 m->count = m->size;
24}
25
26static void *seq_buf_alloc(unsigned long size)
27{
28 void *buf;
29 gfp_t gfp = GFP_KERNEL;
30
31
32
33
34
35
36
37 if (size > PAGE_SIZE)
38 gfp |= __GFP_NORETRY | __GFP_NOWARN;
39 buf = kmalloc(size, gfp);
40 if (!buf && size > PAGE_SIZE)
41 buf = vmalloc(size);
42 return buf;
43}
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61int seq_open(struct file *file, const struct seq_operations *op)
62{
63 struct seq_file *p;
64
65 WARN_ON(file->private_data);
66
67 p = kzalloc(sizeof(*p), GFP_KERNEL);
68 if (!p)
69 return -ENOMEM;
70
71 file->private_data = p;
72
73 mutex_init(&p->lock);
74 p->op = op;
75
76
77
78 p->file = file;
79
80
81
82
83
84
85 file->f_version = 0;
86
87
88
89
90
91
92
93
94
95
96 file->f_mode &= ~FMODE_PWRITE;
97 return 0;
98}
99EXPORT_SYMBOL(seq_open);
100
101static int traverse(struct seq_file *m, loff_t offset)
102{
103 loff_t pos = 0, index;
104 int error = 0;
105 void *p;
106
107 m->version = 0;
108 index = 0;
109 m->count = m->from = 0;
110 if (!offset) {
111 m->index = index;
112 return 0;
113 }
114 if (!m->buf) {
115 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
116 if (!m->buf)
117 return -ENOMEM;
118 }
119 p = m->op->start(m, &index);
120 while (p) {
121 error = PTR_ERR(p);
122 if (IS_ERR(p))
123 break;
124 error = m->op->show(m, p);
125 if (error < 0)
126 break;
127 if (unlikely(error)) {
128 error = 0;
129 m->count = 0;
130 }
131 if (seq_has_overflowed(m))
132 goto Eoverflow;
133 if (pos + m->count > offset) {
134 m->from = offset - pos;
135 m->count -= m->from;
136 m->index = index;
137 break;
138 }
139 pos += m->count;
140 m->count = 0;
141 if (pos == offset) {
142 index++;
143 m->index = index;
144 break;
145 }
146 p = m->op->next(m, p, &index);
147 }
148 m->op->stop(m, p);
149 m->index = index;
150 return error;
151
152Eoverflow:
153 m->op->stop(m, p);
154 kvfree(m->buf);
155 m->count = 0;
156 m->buf = seq_buf_alloc(m->size <<= 1);
157 return !m->buf ? -ENOMEM : -EAGAIN;
158}
159
160
161
162
163
164
165
166
167
168
169ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
170{
171 struct seq_file *m = file->private_data;
172 size_t copied = 0;
173 loff_t pos;
174 size_t n;
175 void *p;
176 int err = 0;
177
178 mutex_lock(&m->lock);
179
180
181
182
183
184
185
186
187
188
189
190
191 m->version = file->f_version;
192
193
194 if (unlikely(*ppos != m->read_pos)) {
195 while ((err = traverse(m, *ppos)) == -EAGAIN)
196 ;
197 if (err) {
198
199 m->read_pos = 0;
200 m->version = 0;
201 m->index = 0;
202 m->count = 0;
203 goto Done;
204 } else {
205 m->read_pos = *ppos;
206 }
207 }
208
209
210 if (!m->buf) {
211 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
212 if (!m->buf)
213 goto Enomem;
214 }
215
216 if (m->count) {
217 n = min(m->count, size);
218 err = copy_to_user(buf, m->buf + m->from, n);
219 if (err)
220 goto Efault;
221 m->count -= n;
222 m->from += n;
223 size -= n;
224 buf += n;
225 copied += n;
226 if (!m->count)
227 m->index++;
228 if (!size)
229 goto Done;
230 }
231
232 pos = m->index;
233 p = m->op->start(m, &pos);
234 while (1) {
235 err = PTR_ERR(p);
236 if (!p || IS_ERR(p))
237 break;
238 err = m->op->show(m, p);
239 if (err < 0)
240 break;
241 if (unlikely(err))
242 m->count = 0;
243 if (unlikely(!m->count)) {
244 p = m->op->next(m, p, &pos);
245 m->index = pos;
246 continue;
247 }
248 if (m->count < m->size)
249 goto Fill;
250 m->op->stop(m, p);
251 kvfree(m->buf);
252 m->count = 0;
253 m->buf = seq_buf_alloc(m->size <<= 1);
254 if (!m->buf)
255 goto Enomem;
256 m->version = 0;
257 pos = m->index;
258 p = m->op->start(m, &pos);
259 }
260 m->op->stop(m, p);
261 m->count = 0;
262 goto Done;
263Fill:
264
265 while (m->count < size) {
266 size_t offs = m->count;
267 loff_t next = pos;
268 p = m->op->next(m, p, &next);
269 if (!p || IS_ERR(p)) {
270 err = PTR_ERR(p);
271 break;
272 }
273 err = m->op->show(m, p);
274 if (seq_has_overflowed(m) || err) {
275 m->count = offs;
276 if (likely(err <= 0))
277 break;
278 }
279 pos = next;
280 }
281 m->op->stop(m, p);
282 n = min(m->count, size);
283 err = copy_to_user(buf, m->buf, n);
284 if (err)
285 goto Efault;
286 copied += n;
287 m->count -= n;
288 if (m->count)
289 m->from = n;
290 else
291 pos++;
292 m->index = pos;
293Done:
294 if (!copied)
295 copied = err;
296 else {
297 *ppos += copied;
298 m->read_pos += copied;
299 }
300 file->f_version = m->version;
301 mutex_unlock(&m->lock);
302 return copied;
303Enomem:
304 err = -ENOMEM;
305 goto Done;
306Efault:
307 err = -EFAULT;
308 goto Done;
309}
310EXPORT_SYMBOL(seq_read);
311
312
313
314
315
316
317
318
319
320loff_t seq_lseek(struct file *file, loff_t offset, int whence)
321{
322 struct seq_file *m = file->private_data;
323 loff_t retval = -EINVAL;
324
325 mutex_lock(&m->lock);
326 m->version = file->f_version;
327 switch (whence) {
328 case SEEK_CUR:
329 offset += file->f_pos;
330 case SEEK_SET:
331 if (offset < 0)
332 break;
333 retval = offset;
334 if (offset != m->read_pos) {
335 while ((retval = traverse(m, offset)) == -EAGAIN)
336 ;
337 if (retval) {
338
339 file->f_pos = 0;
340 m->read_pos = 0;
341 m->version = 0;
342 m->index = 0;
343 m->count = 0;
344 } else {
345 m->read_pos = offset;
346 retval = file->f_pos = offset;
347 }
348 } else {
349 file->f_pos = offset;
350 }
351 }
352 file->f_version = m->version;
353 mutex_unlock(&m->lock);
354 return retval;
355}
356EXPORT_SYMBOL(seq_lseek);
357
358
359
360
361
362
363
364
365
366int seq_release(struct inode *inode, struct file *file)
367{
368 struct seq_file *m = file->private_data;
369 kvfree(m->buf);
370 kfree(m);
371 return 0;
372}
373EXPORT_SYMBOL(seq_release);
374
375
376
377
378
379
380
381
382
383
384
385void seq_escape(struct seq_file *m, const char *s, const char *esc)
386{
387 char *buf;
388 size_t size = seq_get_buf(m, &buf);
389 int ret;
390
391 ret = string_escape_str(s, buf, size, ESCAPE_OCTAL, esc);
392 seq_commit(m, ret < size ? ret : -1);
393}
394EXPORT_SYMBOL(seq_escape);
395
396void seq_vprintf(struct seq_file *m, const char *f, va_list args)
397{
398 int len;
399
400 if (m->count < m->size) {
401 len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
402 if (m->count + len < m->size) {
403 m->count += len;
404 return;
405 }
406 }
407 seq_set_overflow(m);
408}
409EXPORT_SYMBOL(seq_vprintf);
410
411void seq_printf(struct seq_file *m, const char *f, ...)
412{
413 va_list args;
414
415 va_start(args, f);
416 seq_vprintf(m, f, args);
417 va_end(args);
418}
419EXPORT_SYMBOL(seq_printf);
420
421
422
423
424
425
426
427
428
429
430
431
432char *mangle_path(char *s, const char *p, const char *esc)
433{
434 while (s <= p) {
435 char c = *p++;
436 if (!c) {
437 return s;
438 } else if (!strchr(esc, c)) {
439 *s++ = c;
440 } else if (s + 4 > p) {
441 break;
442 } else {
443 *s++ = '\\';
444 *s++ = '0' + ((c & 0300) >> 6);
445 *s++ = '0' + ((c & 070) >> 3);
446 *s++ = '0' + (c & 07);
447 }
448 }
449 return NULL;
450}
451EXPORT_SYMBOL(mangle_path);
452
453
454
455
456
457
458
459
460
461
462int seq_path(struct seq_file *m, const struct path *path, const char *esc)
463{
464 char *buf;
465 size_t size = seq_get_buf(m, &buf);
466 int res = -1;
467
468 if (size) {
469 char *p = d_path(path, buf, size);
470 if (!IS_ERR(p)) {
471 char *end = mangle_path(buf, p, esc);
472 if (end)
473 res = end - buf;
474 }
475 }
476 seq_commit(m, res);
477
478 return res;
479}
480EXPORT_SYMBOL(seq_path);
481
482
483
484
485
486
487
488
489
490int seq_file_path(struct seq_file *m, struct file *file, const char *esc)
491{
492 return seq_path(m, &file->f_path, esc);
493}
494EXPORT_SYMBOL(seq_file_path);
495
496
497
498
499int seq_path_root(struct seq_file *m, const struct path *path,
500 const struct path *root, const char *esc)
501{
502 char *buf;
503 size_t size = seq_get_buf(m, &buf);
504 int res = -ENAMETOOLONG;
505
506 if (size) {
507 char *p;
508
509 p = __d_path(path, root, buf, size);
510 if (!p)
511 return SEQ_SKIP;
512 res = PTR_ERR(p);
513 if (!IS_ERR(p)) {
514 char *end = mangle_path(buf, p, esc);
515 if (end)
516 res = end - buf;
517 else
518 res = -ENAMETOOLONG;
519 }
520 }
521 seq_commit(m, res);
522
523 return res < 0 && res != -ENAMETOOLONG ? res : 0;
524}
525
526
527
528
529int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc)
530{
531 char *buf;
532 size_t size = seq_get_buf(m, &buf);
533 int res = -1;
534
535 if (size) {
536 char *p = dentry_path(dentry, buf, size);
537 if (!IS_ERR(p)) {
538 char *end = mangle_path(buf, p, esc);
539 if (end)
540 res = end - buf;
541 }
542 }
543 seq_commit(m, res);
544
545 return res;
546}
547EXPORT_SYMBOL(seq_dentry);
548
549static void *single_start(struct seq_file *p, loff_t *pos)
550{
551 return NULL + (*pos == 0);
552}
553
554static void *single_next(struct seq_file *p, void *v, loff_t *pos)
555{
556 ++*pos;
557 return NULL;
558}
559
560static void single_stop(struct seq_file *p, void *v)
561{
562}
563
564int single_open(struct file *file, int (*show)(struct seq_file *, void *),
565 void *data)
566{
567 struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL);
568 int res = -ENOMEM;
569
570 if (op) {
571 op->start = single_start;
572 op->next = single_next;
573 op->stop = single_stop;
574 op->show = show;
575 res = seq_open(file, op);
576 if (!res)
577 ((struct seq_file *)file->private_data)->private = data;
578 else
579 kfree(op);
580 }
581 return res;
582}
583EXPORT_SYMBOL(single_open);
584
585int single_open_size(struct file *file, int (*show)(struct seq_file *, void *),
586 void *data, size_t size)
587{
588 char *buf = seq_buf_alloc(size);
589 int ret;
590 if (!buf)
591 return -ENOMEM;
592 ret = single_open(file, show, data);
593 if (ret) {
594 kvfree(buf);
595 return ret;
596 }
597 ((struct seq_file *)file->private_data)->buf = buf;
598 ((struct seq_file *)file->private_data)->size = size;
599 return 0;
600}
601EXPORT_SYMBOL(single_open_size);
602
603int single_release(struct inode *inode, struct file *file)
604{
605 const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
606 int res = seq_release(inode, file);
607 kfree(op);
608 return res;
609}
610EXPORT_SYMBOL(single_release);
611
612int seq_release_private(struct inode *inode, struct file *file)
613{
614 struct seq_file *seq = file->private_data;
615
616 kfree(seq->private);
617 seq->private = NULL;
618 return seq_release(inode, file);
619}
620EXPORT_SYMBOL(seq_release_private);
621
622void *__seq_open_private(struct file *f, const struct seq_operations *ops,
623 int psize)
624{
625 int rc;
626 void *private;
627 struct seq_file *seq;
628
629 private = kzalloc(psize, GFP_KERNEL);
630 if (private == NULL)
631 goto out;
632
633 rc = seq_open(f, ops);
634 if (rc < 0)
635 goto out_free;
636
637 seq = f->private_data;
638 seq->private = private;
639 return private;
640
641out_free:
642 kfree(private);
643out:
644 return NULL;
645}
646EXPORT_SYMBOL(__seq_open_private);
647
648int seq_open_private(struct file *filp, const struct seq_operations *ops,
649 int psize)
650{
651 return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;
652}
653EXPORT_SYMBOL(seq_open_private);
654
655void seq_putc(struct seq_file *m, char c)
656{
657 if (m->count >= m->size)
658 return;
659
660 m->buf[m->count++] = c;
661}
662EXPORT_SYMBOL(seq_putc);
663
664void seq_puts(struct seq_file *m, const char *s)
665{
666 int len = strlen(s);
667
668 if (m->count + len >= m->size) {
669 seq_set_overflow(m);
670 return;
671 }
672 memcpy(m->buf + m->count, s, len);
673 m->count += len;
674}
675EXPORT_SYMBOL(seq_puts);
676
677
678
679
680
681
682
683
684void seq_put_decimal_ull(struct seq_file *m, char delimiter,
685 unsigned long long num)
686{
687 int len;
688
689 if (m->count + 2 >= m->size)
690 goto overflow;
691
692 if (delimiter)
693 m->buf[m->count++] = delimiter;
694
695 if (num < 10) {
696 m->buf[m->count++] = num + '0';
697 return;
698 }
699
700 len = num_to_str(m->buf + m->count, m->size - m->count, num);
701 if (!len)
702 goto overflow;
703 m->count += len;
704 return;
705
706overflow:
707 seq_set_overflow(m);
708}
709EXPORT_SYMBOL(seq_put_decimal_ull);
710
711void seq_put_decimal_ll(struct seq_file *m, char delimiter, long long num)
712{
713 if (num < 0) {
714 if (m->count + 3 >= m->size) {
715 seq_set_overflow(m);
716 return;
717 }
718 if (delimiter)
719 m->buf[m->count++] = delimiter;
720 num = -num;
721 delimiter = '-';
722 }
723 seq_put_decimal_ull(m, delimiter, num);
724}
725EXPORT_SYMBOL(seq_put_decimal_ll);
726
727
728
729
730
731
732
733
734
735int seq_write(struct seq_file *seq, const void *data, size_t len)
736{
737 if (seq->count + len < seq->size) {
738 memcpy(seq->buf + seq->count, data, len);
739 seq->count += len;
740 return 0;
741 }
742 seq_set_overflow(seq);
743 return -1;
744}
745EXPORT_SYMBOL(seq_write);
746
747
748
749
750
751
752void seq_pad(struct seq_file *m, char c)
753{
754 int size = m->pad_until - m->count;
755 if (size > 0)
756 seq_printf(m, "%*s", size, "");
757 if (c)
758 seq_putc(m, c);
759}
760EXPORT_SYMBOL(seq_pad);
761
762
763void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
764 int rowsize, int groupsize, const void *buf, size_t len,
765 bool ascii)
766{
767 const u8 *ptr = buf;
768 int i, linelen, remaining = len;
769 char *buffer;
770 size_t size;
771 int ret;
772
773 if (rowsize != 16 && rowsize != 32)
774 rowsize = 16;
775
776 for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) {
777 linelen = min(remaining, rowsize);
778 remaining -= rowsize;
779
780 switch (prefix_type) {
781 case DUMP_PREFIX_ADDRESS:
782 seq_printf(m, "%s%p: ", prefix_str, ptr + i);
783 break;
784 case DUMP_PREFIX_OFFSET:
785 seq_printf(m, "%s%.8x: ", prefix_str, i);
786 break;
787 default:
788 seq_printf(m, "%s", prefix_str);
789 break;
790 }
791
792 size = seq_get_buf(m, &buffer);
793 ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
794 buffer, size, ascii);
795 seq_commit(m, ret < size ? ret : -1);
796
797 seq_putc(m, '\n');
798 }
799}
800EXPORT_SYMBOL(seq_hex_dump);
801
802struct list_head *seq_list_start(struct list_head *head, loff_t pos)
803{
804 struct list_head *lh;
805
806 list_for_each(lh, head)
807 if (pos-- == 0)
808 return lh;
809
810 return NULL;
811}
812EXPORT_SYMBOL(seq_list_start);
813
814struct list_head *seq_list_start_head(struct list_head *head, loff_t pos)
815{
816 if (!pos)
817 return head;
818
819 return seq_list_start(head, pos - 1);
820}
821EXPORT_SYMBOL(seq_list_start_head);
822
823struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos)
824{
825 struct list_head *lh;
826
827 lh = ((struct list_head *)v)->next;
828 ++*ppos;
829 return lh == head ? NULL : lh;
830}
831EXPORT_SYMBOL(seq_list_next);
832
833
834
835
836
837
838
839
840struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos)
841{
842 struct hlist_node *node;
843
844 hlist_for_each(node, head)
845 if (pos-- == 0)
846 return node;
847 return NULL;
848}
849EXPORT_SYMBOL(seq_hlist_start);
850
851
852
853
854
855
856
857
858
859struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos)
860{
861 if (!pos)
862 return SEQ_START_TOKEN;
863
864 return seq_hlist_start(head, pos - 1);
865}
866EXPORT_SYMBOL(seq_hlist_start_head);
867
868
869
870
871
872
873
874
875
876struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
877 loff_t *ppos)
878{
879 struct hlist_node *node = v;
880
881 ++*ppos;
882 if (v == SEQ_START_TOKEN)
883 return head->first;
884 else
885 return node->next;
886}
887EXPORT_SYMBOL(seq_hlist_next);
888
889
890
891
892
893
894
895
896
897
898
899
900struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
901 loff_t pos)
902{
903 struct hlist_node *node;
904
905 __hlist_for_each_rcu(node, head)
906 if (pos-- == 0)
907 return node;
908 return NULL;
909}
910EXPORT_SYMBOL(seq_hlist_start_rcu);
911
912
913
914
915
916
917
918
919
920
921
922
923
924struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
925 loff_t pos)
926{
927 if (!pos)
928 return SEQ_START_TOKEN;
929
930 return seq_hlist_start_rcu(head, pos - 1);
931}
932EXPORT_SYMBOL(seq_hlist_start_head_rcu);
933
934
935
936
937
938
939
940
941
942
943
944
945
946struct hlist_node *seq_hlist_next_rcu(void *v,
947 struct hlist_head *head,
948 loff_t *ppos)
949{
950 struct hlist_node *node = v;
951
952 ++*ppos;
953 if (v == SEQ_START_TOKEN)
954 return rcu_dereference(head->first);
955 else
956 return rcu_dereference(node->next);
957}
958EXPORT_SYMBOL(seq_hlist_next_rcu);
959
960
961
962
963
964
965
966
967
968struct hlist_node *
969seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos)
970{
971 struct hlist_node *node;
972
973 for_each_possible_cpu(*cpu) {
974 hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
975 if (pos-- == 0)
976 return node;
977 }
978 }
979 return NULL;
980}
981EXPORT_SYMBOL(seq_hlist_start_percpu);
982
983
984
985
986
987
988
989
990
991
992struct hlist_node *
993seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
994 int *cpu, loff_t *pos)
995{
996 struct hlist_node *node = v;
997
998 ++*pos;
999
1000 if (node->next)
1001 return node->next;
1002
1003 for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
1004 *cpu = cpumask_next(*cpu, cpu_possible_mask)) {
1005 struct hlist_head *bucket = per_cpu_ptr(head, *cpu);
1006
1007 if (!hlist_empty(bucket))
1008 return bucket->first;
1009 }
1010 return NULL;
1011}
1012EXPORT_SYMBOL(seq_hlist_next_percpu);
1013