Line data Source code
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 : #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 :
11 : #include <linux/cache.h>
12 : #include <linux/fs.h>
13 : #include <linux/export.h>
14 : #include <linux/seq_file.h>
15 : #include <linux/vmalloc.h>
16 : #include <linux/slab.h>
17 : #include <linux/cred.h>
18 : #include <linux/mm.h>
19 : #include <linux/printk.h>
20 : #include <linux/string_helpers.h>
21 : #include <linux/uio.h>
22 :
23 : #include <linux/uaccess.h>
24 : #include <asm/page.h>
25 :
26 : static struct kmem_cache *seq_file_cache __ro_after_init;
27 :
28 : static void seq_set_overflow(struct seq_file *m)
29 : {
30 0 : m->count = m->size;
31 : }
32 :
33 : static void *seq_buf_alloc(unsigned long size)
34 : {
35 0 : if (unlikely(size > MAX_RW_COUNT))
36 : return NULL;
37 :
38 0 : return kvmalloc(size, GFP_KERNEL_ACCOUNT);
39 : }
40 :
41 : /**
42 : * seq_open - initialize sequential file
43 : * @file: file we initialize
44 : * @op: method table describing the sequence
45 : *
46 : * seq_open() sets @file, associating it with a sequence described
47 : * by @op. @op->start() sets the iterator up and returns the first
48 : * element of sequence. @op->stop() shuts it down. @op->next()
49 : * returns the next element of sequence. @op->show() prints element
50 : * into the buffer. In case of error ->start() and ->next() return
51 : * ERR_PTR(error). In the end of sequence they return %NULL. ->show()
52 : * returns 0 in case of success and negative number in case of error.
53 : * Returning SEQ_SKIP means "discard this element and move on".
54 : * Note: seq_open() will allocate a struct seq_file and store its
55 : * pointer in @file->private_data. This pointer should not be modified.
56 : */
57 0 : int seq_open(struct file *file, const struct seq_operations *op)
58 : {
59 : struct seq_file *p;
60 :
61 0 : WARN_ON(file->private_data);
62 :
63 0 : p = kmem_cache_zalloc(seq_file_cache, GFP_KERNEL);
64 0 : if (!p)
65 : return -ENOMEM;
66 :
67 0 : file->private_data = p;
68 :
69 0 : mutex_init(&p->lock);
70 0 : p->op = op;
71 :
72 : // No refcounting: the lifetime of 'p' is constrained
73 : // to the lifetime of the file.
74 0 : p->file = file;
75 :
76 : /*
77 : * seq_files support lseek() and pread(). They do not implement
78 : * write() at all, but we clear FMODE_PWRITE here for historical
79 : * reasons.
80 : *
81 : * If a client of seq_files a) implements file.write() and b) wishes to
82 : * support pwrite() then that client will need to implement its own
83 : * file.open() which calls seq_open() and then sets FMODE_PWRITE.
84 : */
85 0 : file->f_mode &= ~FMODE_PWRITE;
86 0 : return 0;
87 : }
88 : EXPORT_SYMBOL(seq_open);
89 :
90 0 : static int traverse(struct seq_file *m, loff_t offset)
91 : {
92 0 : loff_t pos = 0;
93 0 : int error = 0;
94 : void *p;
95 :
96 0 : m->index = 0;
97 0 : m->count = m->from = 0;
98 0 : if (!offset)
99 : return 0;
100 :
101 0 : if (!m->buf) {
102 0 : m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
103 0 : if (!m->buf)
104 : return -ENOMEM;
105 : }
106 0 : p = m->op->start(m, &m->index);
107 0 : while (p) {
108 0 : error = PTR_ERR(p);
109 0 : if (IS_ERR(p))
110 : break;
111 0 : error = m->op->show(m, p);
112 0 : if (error < 0)
113 : break;
114 0 : if (unlikely(error)) {
115 0 : error = 0;
116 0 : m->count = 0;
117 : }
118 0 : if (seq_has_overflowed(m))
119 : goto Eoverflow;
120 0 : p = m->op->next(m, p, &m->index);
121 0 : if (pos + m->count > offset) {
122 0 : m->from = offset - pos;
123 0 : m->count -= m->from;
124 0 : break;
125 : }
126 0 : pos += m->count;
127 0 : m->count = 0;
128 0 : if (pos == offset)
129 : break;
130 : }
131 0 : m->op->stop(m, p);
132 0 : return error;
133 :
134 : Eoverflow:
135 0 : m->op->stop(m, p);
136 0 : kvfree(m->buf);
137 0 : m->count = 0;
138 0 : m->buf = seq_buf_alloc(m->size <<= 1);
139 0 : return !m->buf ? -ENOMEM : -EAGAIN;
140 : }
141 :
142 : /**
143 : * seq_read - ->read() method for sequential files.
144 : * @file: the file to read from
145 : * @buf: the buffer to read to
146 : * @size: the maximum number of bytes to read
147 : * @ppos: the current position in the file
148 : *
149 : * Ready-made ->f_op->read()
150 : */
151 0 : ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
152 : {
153 0 : struct iovec iov = { .iov_base = buf, .iov_len = size};
154 : struct kiocb kiocb;
155 : struct iov_iter iter;
156 : ssize_t ret;
157 :
158 0 : init_sync_kiocb(&kiocb, file);
159 0 : iov_iter_init(&iter, ITER_DEST, &iov, 1, size);
160 :
161 0 : kiocb.ki_pos = *ppos;
162 0 : ret = seq_read_iter(&kiocb, &iter);
163 0 : *ppos = kiocb.ki_pos;
164 0 : return ret;
165 : }
166 : EXPORT_SYMBOL(seq_read);
167 :
168 : /*
169 : * Ready-made ->f_op->read_iter()
170 : */
171 0 : ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter)
172 : {
173 0 : struct seq_file *m = iocb->ki_filp->private_data;
174 0 : size_t copied = 0;
175 : size_t n;
176 : void *p;
177 0 : int err = 0;
178 :
179 0 : if (!iov_iter_count(iter))
180 : return 0;
181 :
182 0 : mutex_lock(&m->lock);
183 :
184 : /*
185 : * if request is to read from zero offset, reset iterator to first
186 : * record as it might have been already advanced by previous requests
187 : */
188 0 : if (iocb->ki_pos == 0) {
189 0 : m->index = 0;
190 0 : m->count = 0;
191 : }
192 :
193 : /* Don't assume ki_pos is where we left it */
194 0 : if (unlikely(iocb->ki_pos != m->read_pos)) {
195 0 : while ((err = traverse(m, iocb->ki_pos)) == -EAGAIN)
196 : ;
197 0 : if (err) {
198 : /* With prejudice... */
199 0 : m->read_pos = 0;
200 0 : m->index = 0;
201 0 : m->count = 0;
202 0 : goto Done;
203 : } else {
204 0 : m->read_pos = iocb->ki_pos;
205 : }
206 : }
207 :
208 : /* grab buffer if we didn't have one */
209 0 : if (!m->buf) {
210 0 : m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
211 0 : if (!m->buf)
212 : goto Enomem;
213 : }
214 : // something left in the buffer - copy it out first
215 0 : if (m->count) {
216 0 : n = copy_to_iter(m->buf + m->from, m->count, iter);
217 0 : m->count -= n;
218 0 : m->from += n;
219 0 : copied += n;
220 0 : if (m->count) // hadn't managed to copy everything
221 : goto Done;
222 : }
223 : // get a non-empty record in the buffer
224 0 : m->from = 0;
225 0 : p = m->op->start(m, &m->index);
226 : while (1) {
227 0 : err = PTR_ERR(p);
228 0 : if (!p || IS_ERR(p)) // EOF or an error
229 : break;
230 0 : err = m->op->show(m, p);
231 0 : if (err < 0) // hard error
232 : break;
233 0 : if (unlikely(err)) // ->show() says "skip it"
234 0 : m->count = 0;
235 0 : if (unlikely(!m->count)) { // empty record
236 0 : p = m->op->next(m, p, &m->index);
237 0 : continue;
238 : }
239 0 : if (!seq_has_overflowed(m)) // got it
240 : goto Fill;
241 : // need a bigger buffer
242 0 : m->op->stop(m, p);
243 0 : kvfree(m->buf);
244 0 : m->count = 0;
245 0 : m->buf = seq_buf_alloc(m->size <<= 1);
246 0 : if (!m->buf)
247 : goto Enomem;
248 0 : p = m->op->start(m, &m->index);
249 : }
250 : // EOF or an error
251 0 : m->op->stop(m, p);
252 0 : m->count = 0;
253 0 : goto Done;
254 : Fill:
255 : // one non-empty record is in the buffer; if they want more,
256 : // try to fit more in, but in any case we need to advance
257 : // the iterator once for every record shown.
258 : while (1) {
259 0 : size_t offs = m->count;
260 0 : loff_t pos = m->index;
261 :
262 0 : p = m->op->next(m, p, &m->index);
263 0 : if (pos == m->index) {
264 0 : pr_info_ratelimited("buggy .next function %ps did not update position index\n",
265 : m->op->next);
266 0 : m->index++;
267 : }
268 0 : if (!p || IS_ERR(p)) // no next record for us
269 : break;
270 0 : if (m->count >= iov_iter_count(iter))
271 : break;
272 0 : err = m->op->show(m, p);
273 0 : if (err > 0) { // ->show() says "skip it"
274 0 : m->count = offs;
275 0 : } else if (err || seq_has_overflowed(m)) {
276 0 : m->count = offs;
277 0 : break;
278 : }
279 : }
280 0 : m->op->stop(m, p);
281 0 : n = copy_to_iter(m->buf, m->count, iter);
282 0 : copied += n;
283 0 : m->count -= n;
284 0 : m->from = n;
285 : Done:
286 0 : if (unlikely(!copied)) {
287 0 : copied = m->count ? -EFAULT : err;
288 : } else {
289 0 : iocb->ki_pos += copied;
290 0 : m->read_pos += copied;
291 : }
292 0 : mutex_unlock(&m->lock);
293 0 : return copied;
294 : Enomem:
295 : err = -ENOMEM;
296 : goto Done;
297 : }
298 : EXPORT_SYMBOL(seq_read_iter);
299 :
300 : /**
301 : * seq_lseek - ->llseek() method for sequential files.
302 : * @file: the file in question
303 : * @offset: new position
304 : * @whence: 0 for absolute, 1 for relative position
305 : *
306 : * Ready-made ->f_op->llseek()
307 : */
308 0 : loff_t seq_lseek(struct file *file, loff_t offset, int whence)
309 : {
310 0 : struct seq_file *m = file->private_data;
311 0 : loff_t retval = -EINVAL;
312 :
313 0 : mutex_lock(&m->lock);
314 0 : switch (whence) {
315 : case SEEK_CUR:
316 0 : offset += file->f_pos;
317 : fallthrough;
318 : case SEEK_SET:
319 0 : if (offset < 0)
320 : break;
321 0 : retval = offset;
322 0 : if (offset != m->read_pos) {
323 0 : while ((retval = traverse(m, offset)) == -EAGAIN)
324 : ;
325 0 : if (retval) {
326 : /* with extreme prejudice... */
327 0 : file->f_pos = 0;
328 0 : m->read_pos = 0;
329 0 : m->index = 0;
330 0 : m->count = 0;
331 : } else {
332 0 : m->read_pos = offset;
333 0 : retval = file->f_pos = offset;
334 : }
335 : } else {
336 0 : file->f_pos = offset;
337 : }
338 : }
339 0 : mutex_unlock(&m->lock);
340 0 : return retval;
341 : }
342 : EXPORT_SYMBOL(seq_lseek);
343 :
344 : /**
345 : * seq_release - free the structures associated with sequential file.
346 : * @file: file in question
347 : * @inode: its inode
348 : *
349 : * Frees the structures associated with sequential file; can be used
350 : * as ->f_op->release() if you don't have private data to destroy.
351 : */
352 0 : int seq_release(struct inode *inode, struct file *file)
353 : {
354 0 : struct seq_file *m = file->private_data;
355 0 : kvfree(m->buf);
356 0 : kmem_cache_free(seq_file_cache, m);
357 0 : return 0;
358 : }
359 : EXPORT_SYMBOL(seq_release);
360 :
361 : /**
362 : * seq_escape_mem - print data into buffer, escaping some characters
363 : * @m: target buffer
364 : * @src: source buffer
365 : * @len: size of source buffer
366 : * @flags: flags to pass to string_escape_mem()
367 : * @esc: set of characters that need escaping
368 : *
369 : * Puts data into buffer, replacing each occurrence of character from
370 : * given class (defined by @flags and @esc) with printable escaped sequence.
371 : *
372 : * Use seq_has_overflowed() to check for errors.
373 : */
374 0 : void seq_escape_mem(struct seq_file *m, const char *src, size_t len,
375 : unsigned int flags, const char *esc)
376 : {
377 : char *buf;
378 0 : size_t size = seq_get_buf(m, &buf);
379 : int ret;
380 :
381 0 : ret = string_escape_mem(src, len, buf, size, flags, esc);
382 0 : seq_commit(m, ret < size ? ret : -1);
383 0 : }
384 : EXPORT_SYMBOL(seq_escape_mem);
385 :
386 0 : void seq_vprintf(struct seq_file *m, const char *f, va_list args)
387 : {
388 : int len;
389 :
390 0 : if (m->count < m->size) {
391 0 : len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
392 0 : if (m->count + len < m->size) {
393 0 : m->count += len;
394 0 : return;
395 : }
396 : }
397 0 : seq_set_overflow(m);
398 : }
399 : EXPORT_SYMBOL(seq_vprintf);
400 :
401 0 : void seq_printf(struct seq_file *m, const char *f, ...)
402 : {
403 : va_list args;
404 :
405 0 : va_start(args, f);
406 0 : seq_vprintf(m, f, args);
407 0 : va_end(args);
408 0 : }
409 : EXPORT_SYMBOL(seq_printf);
410 :
411 : #ifdef CONFIG_BINARY_PRINTF
412 : void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary)
413 : {
414 : int len;
415 :
416 : if (m->count < m->size) {
417 : len = bstr_printf(m->buf + m->count, m->size - m->count, f,
418 : binary);
419 : if (m->count + len < m->size) {
420 : m->count += len;
421 : return;
422 : }
423 : }
424 : seq_set_overflow(m);
425 : }
426 : EXPORT_SYMBOL(seq_bprintf);
427 : #endif /* CONFIG_BINARY_PRINTF */
428 :
429 : /**
430 : * mangle_path - mangle and copy path to buffer beginning
431 : * @s: buffer start
432 : * @p: beginning of path in above buffer
433 : * @esc: set of characters that need escaping
434 : *
435 : * Copy the path from @p to @s, replacing each occurrence of character from
436 : * @esc with usual octal escape.
437 : * Returns pointer past last written character in @s, or NULL in case of
438 : * failure.
439 : */
440 0 : char *mangle_path(char *s, const char *p, const char *esc)
441 : {
442 0 : while (s <= p) {
443 0 : char c = *p++;
444 0 : if (!c) {
445 : return s;
446 0 : } else if (!strchr(esc, c)) {
447 0 : *s++ = c;
448 0 : } else if (s + 4 > p) {
449 : break;
450 : } else {
451 0 : *s++ = '\\';
452 0 : *s++ = '0' + ((c & 0300) >> 6);
453 0 : *s++ = '0' + ((c & 070) >> 3);
454 0 : *s++ = '0' + (c & 07);
455 : }
456 : }
457 : return NULL;
458 : }
459 : EXPORT_SYMBOL(mangle_path);
460 :
461 : /**
462 : * seq_path - seq_file interface to print a pathname
463 : * @m: the seq_file handle
464 : * @path: the struct path to print
465 : * @esc: set of characters to escape in the output
466 : *
467 : * return the absolute path of 'path', as represented by the
468 : * dentry / mnt pair in the path parameter.
469 : */
470 0 : int seq_path(struct seq_file *m, const struct path *path, const char *esc)
471 : {
472 : char *buf;
473 0 : size_t size = seq_get_buf(m, &buf);
474 0 : int res = -1;
475 :
476 0 : if (size) {
477 0 : char *p = d_path(path, buf, size);
478 0 : if (!IS_ERR(p)) {
479 0 : char *end = mangle_path(buf, p, esc);
480 0 : if (end)
481 0 : res = end - buf;
482 : }
483 : }
484 0 : seq_commit(m, res);
485 :
486 0 : return res;
487 : }
488 : EXPORT_SYMBOL(seq_path);
489 :
490 : /**
491 : * seq_file_path - seq_file interface to print a pathname of a file
492 : * @m: the seq_file handle
493 : * @file: the struct file to print
494 : * @esc: set of characters to escape in the output
495 : *
496 : * return the absolute path to the file.
497 : */
498 0 : int seq_file_path(struct seq_file *m, struct file *file, const char *esc)
499 : {
500 0 : return seq_path(m, &file->f_path, esc);
501 : }
502 : EXPORT_SYMBOL(seq_file_path);
503 :
504 : /*
505 : * Same as seq_path, but relative to supplied root.
506 : */
507 0 : int seq_path_root(struct seq_file *m, const struct path *path,
508 : const struct path *root, const char *esc)
509 : {
510 : char *buf;
511 0 : size_t size = seq_get_buf(m, &buf);
512 0 : int res = -ENAMETOOLONG;
513 :
514 0 : if (size) {
515 : char *p;
516 :
517 0 : p = __d_path(path, root, buf, size);
518 0 : if (!p)
519 : return SEQ_SKIP;
520 0 : res = PTR_ERR(p);
521 0 : if (!IS_ERR(p)) {
522 0 : char *end = mangle_path(buf, p, esc);
523 0 : if (end)
524 0 : res = end - buf;
525 : else
526 : res = -ENAMETOOLONG;
527 : }
528 : }
529 0 : seq_commit(m, res);
530 :
531 0 : return res < 0 && res != -ENAMETOOLONG ? res : 0;
532 : }
533 :
534 : /*
535 : * returns the path of the 'dentry' from the root of its filesystem.
536 : */
537 0 : int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc)
538 : {
539 : char *buf;
540 0 : size_t size = seq_get_buf(m, &buf);
541 0 : int res = -1;
542 :
543 0 : if (size) {
544 0 : char *p = dentry_path(dentry, buf, size);
545 0 : if (!IS_ERR(p)) {
546 0 : char *end = mangle_path(buf, p, esc);
547 0 : if (end)
548 0 : res = end - buf;
549 : }
550 : }
551 0 : seq_commit(m, res);
552 :
553 0 : return res;
554 : }
555 : EXPORT_SYMBOL(seq_dentry);
556 :
557 0 : void *single_start(struct seq_file *p, loff_t *pos)
558 : {
559 0 : return *pos ? NULL : SEQ_START_TOKEN;
560 : }
561 :
562 0 : static void *single_next(struct seq_file *p, void *v, loff_t *pos)
563 : {
564 0 : ++*pos;
565 0 : return NULL;
566 : }
567 :
568 0 : static void single_stop(struct seq_file *p, void *v)
569 : {
570 0 : }
571 :
572 0 : int single_open(struct file *file, int (*show)(struct seq_file *, void *),
573 : void *data)
574 : {
575 0 : struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL_ACCOUNT);
576 0 : int res = -ENOMEM;
577 :
578 0 : if (op) {
579 0 : op->start = single_start;
580 0 : op->next = single_next;
581 0 : op->stop = single_stop;
582 0 : op->show = show;
583 0 : res = seq_open(file, op);
584 0 : if (!res)
585 0 : ((struct seq_file *)file->private_data)->private = data;
586 : else
587 0 : kfree(op);
588 : }
589 0 : return res;
590 : }
591 : EXPORT_SYMBOL(single_open);
592 :
593 0 : int single_open_size(struct file *file, int (*show)(struct seq_file *, void *),
594 : void *data, size_t size)
595 : {
596 0 : char *buf = seq_buf_alloc(size);
597 : int ret;
598 0 : if (!buf)
599 : return -ENOMEM;
600 0 : ret = single_open(file, show, data);
601 0 : if (ret) {
602 0 : kvfree(buf);
603 0 : return ret;
604 : }
605 0 : ((struct seq_file *)file->private_data)->buf = buf;
606 0 : ((struct seq_file *)file->private_data)->size = size;
607 0 : return 0;
608 : }
609 : EXPORT_SYMBOL(single_open_size);
610 :
611 0 : int single_release(struct inode *inode, struct file *file)
612 : {
613 0 : const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
614 0 : int res = seq_release(inode, file);
615 0 : kfree(op);
616 0 : return res;
617 : }
618 : EXPORT_SYMBOL(single_release);
619 :
620 0 : int seq_release_private(struct inode *inode, struct file *file)
621 : {
622 0 : struct seq_file *seq = file->private_data;
623 :
624 0 : kfree(seq->private);
625 0 : seq->private = NULL;
626 0 : return seq_release(inode, file);
627 : }
628 : EXPORT_SYMBOL(seq_release_private);
629 :
630 0 : void *__seq_open_private(struct file *f, const struct seq_operations *ops,
631 : int psize)
632 : {
633 : int rc;
634 : void *private;
635 : struct seq_file *seq;
636 :
637 0 : private = kzalloc(psize, GFP_KERNEL_ACCOUNT);
638 0 : if (private == NULL)
639 : goto out;
640 :
641 0 : rc = seq_open(f, ops);
642 0 : if (rc < 0)
643 : goto out_free;
644 :
645 0 : seq = f->private_data;
646 0 : seq->private = private;
647 0 : return private;
648 :
649 : out_free:
650 0 : kfree(private);
651 : out:
652 : return NULL;
653 : }
654 : EXPORT_SYMBOL(__seq_open_private);
655 :
656 0 : int seq_open_private(struct file *filp, const struct seq_operations *ops,
657 : int psize)
658 : {
659 0 : return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;
660 : }
661 : EXPORT_SYMBOL(seq_open_private);
662 :
663 0 : void seq_putc(struct seq_file *m, char c)
664 : {
665 0 : if (m->count >= m->size)
666 : return;
667 :
668 0 : m->buf[m->count++] = c;
669 : }
670 : EXPORT_SYMBOL(seq_putc);
671 :
672 0 : void seq_puts(struct seq_file *m, const char *s)
673 : {
674 0 : int len = strlen(s);
675 :
676 0 : if (m->count + len >= m->size) {
677 0 : seq_set_overflow(m);
678 : return;
679 : }
680 0 : memcpy(m->buf + m->count, s, len);
681 0 : m->count += len;
682 : }
683 : EXPORT_SYMBOL(seq_puts);
684 :
685 : /**
686 : * seq_put_decimal_ull_width - A helper routine for putting decimal numbers
687 : * without rich format of printf().
688 : * only 'unsigned long long' is supported.
689 : * @m: seq_file identifying the buffer to which data should be written
690 : * @delimiter: a string which is printed before the number
691 : * @num: the number
692 : * @width: a minimum field width
693 : *
694 : * This routine will put strlen(delimiter) + number into seq_filed.
695 : * This routine is very quick when you show lots of numbers.
696 : * In usual cases, it will be better to use seq_printf(). It's easier to read.
697 : */
698 0 : void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
699 : unsigned long long num, unsigned int width)
700 : {
701 : int len;
702 :
703 0 : if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */
704 : goto overflow;
705 :
706 0 : if (delimiter && delimiter[0]) {
707 0 : if (delimiter[1] == 0)
708 0 : seq_putc(m, delimiter[0]);
709 : else
710 0 : seq_puts(m, delimiter);
711 : }
712 :
713 0 : if (!width)
714 0 : width = 1;
715 :
716 0 : if (m->count + width >= m->size)
717 : goto overflow;
718 :
719 0 : len = num_to_str(m->buf + m->count, m->size - m->count, num, width);
720 0 : if (!len)
721 : goto overflow;
722 :
723 0 : m->count += len;
724 0 : return;
725 :
726 : overflow:
727 0 : seq_set_overflow(m);
728 : }
729 :
730 0 : void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
731 : unsigned long long num)
732 : {
733 0 : return seq_put_decimal_ull_width(m, delimiter, num, 0);
734 : }
735 : EXPORT_SYMBOL(seq_put_decimal_ull);
736 :
737 : /**
738 : * seq_put_hex_ll - put a number in hexadecimal notation
739 : * @m: seq_file identifying the buffer to which data should be written
740 : * @delimiter: a string which is printed before the number
741 : * @v: the number
742 : * @width: a minimum field width
743 : *
744 : * seq_put_hex_ll(m, "", v, 8) is equal to seq_printf(m, "%08llx", v)
745 : *
746 : * This routine is very quick when you show lots of numbers.
747 : * In usual cases, it will be better to use seq_printf(). It's easier to read.
748 : */
749 0 : void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
750 : unsigned long long v, unsigned int width)
751 : {
752 : unsigned int len;
753 : int i;
754 :
755 0 : if (delimiter && delimiter[0]) {
756 0 : if (delimiter[1] == 0)
757 0 : seq_putc(m, delimiter[0]);
758 : else
759 0 : seq_puts(m, delimiter);
760 : }
761 :
762 : /* If x is 0, the result of __builtin_clzll is undefined */
763 0 : if (v == 0)
764 : len = 1;
765 : else
766 0 : len = (sizeof(v) * 8 - __builtin_clzll(v) + 3) / 4;
767 :
768 0 : if (len < width)
769 0 : len = width;
770 :
771 0 : if (m->count + len > m->size) {
772 0 : seq_set_overflow(m);
773 : return;
774 : }
775 :
776 0 : for (i = len - 1; i >= 0; i--) {
777 0 : m->buf[m->count + i] = hex_asc[0xf & v];
778 0 : v = v >> 4;
779 : }
780 0 : m->count += len;
781 : }
782 :
783 0 : void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num)
784 : {
785 : int len;
786 :
787 0 : if (m->count + 3 >= m->size) /* we'll write 2 bytes at least */
788 : goto overflow;
789 :
790 0 : if (delimiter && delimiter[0]) {
791 0 : if (delimiter[1] == 0)
792 0 : seq_putc(m, delimiter[0]);
793 : else
794 0 : seq_puts(m, delimiter);
795 : }
796 :
797 0 : if (m->count + 2 >= m->size)
798 : goto overflow;
799 :
800 0 : if (num < 0) {
801 0 : m->buf[m->count++] = '-';
802 0 : num = -num;
803 : }
804 :
805 0 : if (num < 10) {
806 0 : m->buf[m->count++] = num + '0';
807 0 : return;
808 : }
809 :
810 0 : len = num_to_str(m->buf + m->count, m->size - m->count, num, 0);
811 0 : if (!len)
812 : goto overflow;
813 :
814 0 : m->count += len;
815 0 : return;
816 :
817 : overflow:
818 0 : seq_set_overflow(m);
819 : }
820 : EXPORT_SYMBOL(seq_put_decimal_ll);
821 :
822 : /**
823 : * seq_write - write arbitrary data to buffer
824 : * @seq: seq_file identifying the buffer to which data should be written
825 : * @data: data address
826 : * @len: number of bytes
827 : *
828 : * Return 0 on success, non-zero otherwise.
829 : */
830 0 : int seq_write(struct seq_file *seq, const void *data, size_t len)
831 : {
832 0 : if (seq->count + len < seq->size) {
833 0 : memcpy(seq->buf + seq->count, data, len);
834 0 : seq->count += len;
835 0 : return 0;
836 : }
837 0 : seq_set_overflow(seq);
838 0 : return -1;
839 : }
840 : EXPORT_SYMBOL(seq_write);
841 :
842 : /**
843 : * seq_pad - write padding spaces to buffer
844 : * @m: seq_file identifying the buffer to which data should be written
845 : * @c: the byte to append after padding if non-zero
846 : */
847 0 : void seq_pad(struct seq_file *m, char c)
848 : {
849 0 : int size = m->pad_until - m->count;
850 0 : if (size > 0) {
851 0 : if (size + m->count > m->size) {
852 0 : seq_set_overflow(m);
853 : return;
854 : }
855 0 : memset(m->buf + m->count, ' ', size);
856 0 : m->count += size;
857 : }
858 0 : if (c)
859 0 : seq_putc(m, c);
860 : }
861 : EXPORT_SYMBOL(seq_pad);
862 :
863 : /* A complete analogue of print_hex_dump() */
864 0 : void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
865 : int rowsize, int groupsize, const void *buf, size_t len,
866 : bool ascii)
867 : {
868 0 : const u8 *ptr = buf;
869 0 : int i, linelen, remaining = len;
870 : char *buffer;
871 : size_t size;
872 : int ret;
873 :
874 0 : if (rowsize != 16 && rowsize != 32)
875 0 : rowsize = 16;
876 :
877 0 : for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) {
878 0 : linelen = min(remaining, rowsize);
879 0 : remaining -= rowsize;
880 :
881 0 : switch (prefix_type) {
882 : case DUMP_PREFIX_ADDRESS:
883 0 : seq_printf(m, "%s%p: ", prefix_str, ptr + i);
884 0 : break;
885 : case DUMP_PREFIX_OFFSET:
886 0 : seq_printf(m, "%s%.8x: ", prefix_str, i);
887 0 : break;
888 : default:
889 0 : seq_printf(m, "%s", prefix_str);
890 0 : break;
891 : }
892 :
893 0 : size = seq_get_buf(m, &buffer);
894 0 : ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
895 : buffer, size, ascii);
896 0 : seq_commit(m, ret < size ? ret : -1);
897 :
898 0 : seq_putc(m, '\n');
899 : }
900 0 : }
901 : EXPORT_SYMBOL(seq_hex_dump);
902 :
903 0 : struct list_head *seq_list_start(struct list_head *head, loff_t pos)
904 : {
905 : struct list_head *lh;
906 :
907 0 : list_for_each(lh, head)
908 0 : if (pos-- == 0)
909 : return lh;
910 :
911 : return NULL;
912 : }
913 : EXPORT_SYMBOL(seq_list_start);
914 :
915 0 : struct list_head *seq_list_start_head(struct list_head *head, loff_t pos)
916 : {
917 0 : if (!pos)
918 : return head;
919 :
920 0 : return seq_list_start(head, pos - 1);
921 : }
922 : EXPORT_SYMBOL(seq_list_start_head);
923 :
924 0 : struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos)
925 : {
926 : struct list_head *lh;
927 :
928 0 : lh = ((struct list_head *)v)->next;
929 0 : ++*ppos;
930 0 : return lh == head ? NULL : lh;
931 : }
932 : EXPORT_SYMBOL(seq_list_next);
933 :
934 0 : struct list_head *seq_list_start_rcu(struct list_head *head, loff_t pos)
935 : {
936 : struct list_head *lh;
937 :
938 0 : list_for_each_rcu(lh, head)
939 0 : if (pos-- == 0)
940 : return lh;
941 :
942 : return NULL;
943 : }
944 : EXPORT_SYMBOL(seq_list_start_rcu);
945 :
946 0 : struct list_head *seq_list_start_head_rcu(struct list_head *head, loff_t pos)
947 : {
948 0 : if (!pos)
949 : return head;
950 :
951 0 : return seq_list_start_rcu(head, pos - 1);
952 : }
953 : EXPORT_SYMBOL(seq_list_start_head_rcu);
954 :
955 0 : struct list_head *seq_list_next_rcu(void *v, struct list_head *head,
956 : loff_t *ppos)
957 : {
958 : struct list_head *lh;
959 :
960 0 : lh = list_next_rcu((struct list_head *)v);
961 0 : ++*ppos;
962 0 : return lh == head ? NULL : lh;
963 : }
964 : EXPORT_SYMBOL(seq_list_next_rcu);
965 :
966 : /**
967 : * seq_hlist_start - start an iteration of a hlist
968 : * @head: the head of the hlist
969 : * @pos: the start position of the sequence
970 : *
971 : * Called at seq_file->op->start().
972 : */
973 0 : struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos)
974 : {
975 : struct hlist_node *node;
976 :
977 0 : hlist_for_each(node, head)
978 0 : if (pos-- == 0)
979 : return node;
980 : return NULL;
981 : }
982 : EXPORT_SYMBOL(seq_hlist_start);
983 :
984 : /**
985 : * seq_hlist_start_head - start an iteration of a hlist
986 : * @head: the head of the hlist
987 : * @pos: the start position of the sequence
988 : *
989 : * Called at seq_file->op->start(). Call this function if you want to
990 : * print a header at the top of the output.
991 : */
992 0 : struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos)
993 : {
994 0 : if (!pos)
995 : return SEQ_START_TOKEN;
996 :
997 0 : return seq_hlist_start(head, pos - 1);
998 : }
999 : EXPORT_SYMBOL(seq_hlist_start_head);
1000 :
1001 : /**
1002 : * seq_hlist_next - move to the next position of the hlist
1003 : * @v: the current iterator
1004 : * @head: the head of the hlist
1005 : * @ppos: the current position
1006 : *
1007 : * Called at seq_file->op->next().
1008 : */
1009 0 : struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
1010 : loff_t *ppos)
1011 : {
1012 0 : struct hlist_node *node = v;
1013 :
1014 0 : ++*ppos;
1015 0 : if (v == SEQ_START_TOKEN)
1016 0 : return head->first;
1017 : else
1018 0 : return node->next;
1019 : }
1020 : EXPORT_SYMBOL(seq_hlist_next);
1021 :
1022 : /**
1023 : * seq_hlist_start_rcu - start an iteration of a hlist protected by RCU
1024 : * @head: the head of the hlist
1025 : * @pos: the start position of the sequence
1026 : *
1027 : * Called at seq_file->op->start().
1028 : *
1029 : * This list-traversal primitive may safely run concurrently with
1030 : * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1031 : * as long as the traversal is guarded by rcu_read_lock().
1032 : */
1033 0 : struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
1034 : loff_t pos)
1035 : {
1036 : struct hlist_node *node;
1037 :
1038 0 : __hlist_for_each_rcu(node, head)
1039 0 : if (pos-- == 0)
1040 : return node;
1041 : return NULL;
1042 : }
1043 : EXPORT_SYMBOL(seq_hlist_start_rcu);
1044 :
1045 : /**
1046 : * seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU
1047 : * @head: the head of the hlist
1048 : * @pos: the start position of the sequence
1049 : *
1050 : * Called at seq_file->op->start(). Call this function if you want to
1051 : * print a header at the top of the output.
1052 : *
1053 : * This list-traversal primitive may safely run concurrently with
1054 : * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1055 : * as long as the traversal is guarded by rcu_read_lock().
1056 : */
1057 0 : struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
1058 : loff_t pos)
1059 : {
1060 0 : if (!pos)
1061 : return SEQ_START_TOKEN;
1062 :
1063 0 : return seq_hlist_start_rcu(head, pos - 1);
1064 : }
1065 : EXPORT_SYMBOL(seq_hlist_start_head_rcu);
1066 :
1067 : /**
1068 : * seq_hlist_next_rcu - move to the next position of the hlist protected by RCU
1069 : * @v: the current iterator
1070 : * @head: the head of the hlist
1071 : * @ppos: the current position
1072 : *
1073 : * Called at seq_file->op->next().
1074 : *
1075 : * This list-traversal primitive may safely run concurrently with
1076 : * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1077 : * as long as the traversal is guarded by rcu_read_lock().
1078 : */
1079 0 : struct hlist_node *seq_hlist_next_rcu(void *v,
1080 : struct hlist_head *head,
1081 : loff_t *ppos)
1082 : {
1083 0 : struct hlist_node *node = v;
1084 :
1085 0 : ++*ppos;
1086 0 : if (v == SEQ_START_TOKEN)
1087 0 : return rcu_dereference(head->first);
1088 : else
1089 0 : return rcu_dereference(node->next);
1090 : }
1091 : EXPORT_SYMBOL(seq_hlist_next_rcu);
1092 :
1093 : /**
1094 : * seq_hlist_start_percpu - start an iteration of a percpu hlist array
1095 : * @head: pointer to percpu array of struct hlist_heads
1096 : * @cpu: pointer to cpu "cursor"
1097 : * @pos: start position of sequence
1098 : *
1099 : * Called at seq_file->op->start().
1100 : */
1101 : struct hlist_node *
1102 0 : seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos)
1103 : {
1104 : struct hlist_node *node;
1105 :
1106 0 : for_each_possible_cpu(*cpu) {
1107 0 : hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
1108 0 : if (pos-- == 0)
1109 : return node;
1110 : }
1111 : }
1112 : return NULL;
1113 : }
1114 : EXPORT_SYMBOL(seq_hlist_start_percpu);
1115 :
1116 : /**
1117 : * seq_hlist_next_percpu - move to the next position of the percpu hlist array
1118 : * @v: pointer to current hlist_node
1119 : * @head: pointer to percpu array of struct hlist_heads
1120 : * @cpu: pointer to cpu "cursor"
1121 : * @pos: start position of sequence
1122 : *
1123 : * Called at seq_file->op->next().
1124 : */
1125 : struct hlist_node *
1126 0 : seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
1127 : int *cpu, loff_t *pos)
1128 : {
1129 0 : struct hlist_node *node = v;
1130 :
1131 0 : ++*pos;
1132 :
1133 0 : if (node->next)
1134 : return node->next;
1135 :
1136 0 : for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
1137 0 : *cpu = cpumask_next(*cpu, cpu_possible_mask)) {
1138 0 : struct hlist_head *bucket = per_cpu_ptr(head, *cpu);
1139 :
1140 0 : if (!hlist_empty(bucket))
1141 0 : return bucket->first;
1142 : }
1143 : return NULL;
1144 : }
1145 : EXPORT_SYMBOL(seq_hlist_next_percpu);
1146 :
1147 1 : void __init seq_file_init(void)
1148 : {
1149 1 : seq_file_cache = KMEM_CACHE(seq_file, SLAB_ACCOUNT|SLAB_PANIC);
1150 1 : }
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