blob: 19f532e7d35e9a501256ab64f76a645bf7d6b2e6 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/seq_file.c
3 *
4 * helper functions for making synthetic files from sequences of records.
5 * initial implementation -- AV, Oct 2001.
6 */
7
8#include <linux/fs.h>
Paul Gortmaker630d9c42011-11-16 23:57:37 -05009#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/seq_file.h>
Heiko Carstens058504e2014-07-02 15:22:37 -070011#include <linux/vmalloc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/slab.h>
Eric W. Biedermanadb37c42012-05-23 18:01:20 -060013#include <linux/cred.h>
Heiko Carstens058504e2014-07-02 15:22:37 -070014#include <linux/mm.h>
Andy Shevchenko37607102015-09-09 15:38:33 -070015#include <linux/printk.h>
Andy Shevchenko25c6bb76e2015-11-06 16:32:40 -080016#include <linux/string_helpers.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017
18#include <asm/uaccess.h>
19#include <asm/page.h>
20
KAMEZAWA Hiroyukie075f592012-03-23 15:02:55 -070021static void seq_set_overflow(struct seq_file *m)
22{
23 m->count = m->size;
24}
25
Heiko Carstens058504e2014-07-02 15:22:37 -070026static void *seq_buf_alloc(unsigned long size)
27{
28 void *buf;
Greg Thelen0f930902015-11-06 16:32:42 -080029 gfp_t gfp = GFP_KERNEL;
Heiko Carstens058504e2014-07-02 15:22:37 -070030
David Rientjes5cec38a2014-12-12 16:56:16 -080031 /*
Greg Thelen0f930902015-11-06 16:32:42 -080032 * For high order allocations, use __GFP_NORETRY to avoid oom-killing -
33 * it's better to fall back to vmalloc() than to kill things. For small
34 * allocations, just use GFP_KERNEL which will oom kill, thus no need
35 * for vmalloc fallback.
David Rientjes5cec38a2014-12-12 16:56:16 -080036 */
Greg Thelen0f930902015-11-06 16:32:42 -080037 if (size > PAGE_SIZE)
38 gfp |= __GFP_NORETRY | __GFP_NOWARN;
39 buf = kmalloc(size, gfp);
Heiko Carstens058504e2014-07-02 15:22:37 -070040 if (!buf && size > PAGE_SIZE)
41 buf = vmalloc(size);
42 return buf;
43}
44
Linus Torvalds1da177e2005-04-16 15:20:36 -070045/**
46 * seq_open - initialize sequential file
47 * @file: file we initialize
48 * @op: method table describing the sequence
49 *
50 * seq_open() sets @file, associating it with a sequence described
51 * by @op. @op->start() sets the iterator up and returns the first
52 * element of sequence. @op->stop() shuts it down. @op->next()
53 * returns the next element of sequence. @op->show() prints element
54 * into the buffer. In case of error ->start() and ->next() return
55 * ERR_PTR(error). In the end of sequence they return %NULL. ->show()
56 * returns 0 in case of success and negative number in case of error.
Al Viro521b5d02008-03-28 00:46:41 -040057 * Returning SEQ_SKIP means "discard this element and move on".
Yann Droneaud460b8652015-06-30 14:57:36 -070058 * Note: seq_open() will allocate a struct seq_file and store its
59 * pointer in @file->private_data. This pointer should not be modified.
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 */
Helge Deller15ad7cd2006-12-06 20:40:36 -080061int seq_open(struct file *file, const struct seq_operations *op)
Linus Torvalds1da177e2005-04-16 15:20:36 -070062{
Yann Droneaud189f9842015-06-30 14:57:33 -070063 struct seq_file *p;
Al Viro1abe77b2005-11-07 17:15:34 -050064
Yann Droneaud189f9842015-06-30 14:57:33 -070065 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
Ingo Molnar0ac17592006-03-23 03:00:37 -080073 mutex_init(&p->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 p->op = op;
Linus Torvalds34dbbcd2016-04-14 11:22:00 -070075
76 // No refcounting: the lifetime of 'p' is constrained
77 // to the lifetime of the file.
78 p->file = file;
Linus Torvalds1da177e2005-04-16 15:20:36 -070079
80 /*
81 * Wrappers around seq_open(e.g. swaps_open) need to be
82 * aware of this. If they set f_version themselves, they
83 * should call seq_open first and then set f_version.
84 */
85 file->f_version = 0;
86
Eric Biederman8f19d472009-02-18 14:48:16 -080087 /*
88 * seq_files support lseek() and pread(). They do not implement
89 * write() at all, but we clear FMODE_PWRITE here for historical
90 * reasons.
91 *
92 * If a client of seq_files a) implements file.write() and b) wishes to
93 * support pwrite() then that client will need to implement its own
94 * file.open() which calls seq_open() and then sets FMODE_PWRITE.
95 */
96 file->f_mode &= ~FMODE_PWRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 return 0;
98}
99EXPORT_SYMBOL(seq_open);
100
Eric Biederman33da8892009-02-04 15:12:25 -0800101static 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) {
Heiko Carstens058504e2014-07-02 15:22:37 -0700115 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
Eric Biederman33da8892009-02-04 15:12:25 -0800116 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 }
Joe Perches1f33c412014-09-29 16:08:21 -0700131 if (seq_has_overflowed(m))
Eric Biederman33da8892009-02-04 15:12:25 -0800132 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);
Alexey Dobriyanf01d1d52009-02-06 00:30:05 +0300149 m->index = index;
Eric Biederman33da8892009-02-04 15:12:25 -0800150 return error;
151
152Eoverflow:
153 m->op->stop(m, p);
Heiko Carstens058504e2014-07-02 15:22:37 -0700154 kvfree(m->buf);
Al Viro801a7602013-11-19 01:20:43 +0000155 m->count = 0;
Heiko Carstens058504e2014-07-02 15:22:37 -0700156 m->buf = seq_buf_alloc(m->size <<= 1);
Eric Biederman33da8892009-02-04 15:12:25 -0800157 return !m->buf ? -ENOMEM : -EAGAIN;
158}
159
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160/**
161 * seq_read - ->read() method for sequential files.
Martin Waitz67be2dd2005-05-01 08:59:26 -0700162 * @file: the file to read from
163 * @buf: the buffer to read to
164 * @size: the maximum number of bytes to read
165 * @ppos: the current position in the file
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 *
167 * Ready-made ->f_op->read()
168 */
169ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
170{
Joe Perches8209e2f2010-09-04 18:52:49 -0700171 struct seq_file *m = file->private_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 size_t copied = 0;
173 loff_t pos;
174 size_t n;
175 void *p;
176 int err = 0;
177
Ingo Molnar0ac17592006-03-23 03:00:37 -0800178 mutex_lock(&m->lock);
Eric Biederman8f19d472009-02-18 14:48:16 -0800179
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 /*
181 * seq_file->op->..m_start/m_stop/m_next may do special actions
182 * or optimisations based on the file->f_version, so we want to
183 * pass the file->f_version to those methods.
184 *
185 * seq_file->version is just copy of f_version, and seq_file
186 * methods can treat it simply as file version.
187 * It is copied in first and copied out after all operations.
188 * It is convenient to have it as part of structure to avoid the
189 * need of passing another argument to all the seq_file methods.
190 */
191 m->version = file->f_version;
Earl Chew7904ac82012-03-21 16:33:43 -0700192
193 /* Don't assume *ppos is where we left it */
194 if (unlikely(*ppos != m->read_pos)) {
195 while ((err = traverse(m, *ppos)) == -EAGAIN)
196 ;
197 if (err) {
198 /* With prejudice... */
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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 /* grab buffer if we didn't have one */
210 if (!m->buf) {
Heiko Carstens058504e2014-07-02 15:22:37 -0700211 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 if (!m->buf)
213 goto Enomem;
214 }
215 /* if not empty - flush it first */
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 /* we need at least one record in buffer */
Al Viro4cdfe842008-08-24 07:45:33 -0400232 pos = m->index;
233 p = m->op->start(m, &pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 while (1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 err = PTR_ERR(p);
236 if (!p || IS_ERR(p))
237 break;
238 err = m->op->show(m, p);
Al Viro521b5d02008-03-28 00:46:41 -0400239 if (err < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 break;
Al Viro521b5d02008-03-28 00:46:41 -0400241 if (unlikely(err))
242 m->count = 0;
Al Viro4cdfe842008-08-24 07:45:33 -0400243 if (unlikely(!m->count)) {
244 p = m->op->next(m, p, &pos);
245 m->index = pos;
246 continue;
247 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 if (m->count < m->size)
249 goto Fill;
250 m->op->stop(m, p);
Heiko Carstens058504e2014-07-02 15:22:37 -0700251 kvfree(m->buf);
Al Viro801a7602013-11-19 01:20:43 +0000252 m->count = 0;
Heiko Carstens058504e2014-07-02 15:22:37 -0700253 m->buf = seq_buf_alloc(m->size <<= 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 if (!m->buf)
255 goto Enomem;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 m->version = 0;
Al Viro4cdfe842008-08-24 07:45:33 -0400257 pos = m->index;
258 p = m->op->start(m, &pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 }
260 m->op->stop(m, p);
261 m->count = 0;
262 goto Done;
263Fill:
264 /* they want more? let's try to get some more */
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);
Joe Perches1f33c412014-09-29 16:08:21 -0700274 if (seq_has_overflowed(m) || err) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 m->count = offs;
Al Viro521b5d02008-03-28 00:46:41 -0400276 if (likely(err <= 0))
277 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 }
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;
Eric Biederman8f19d472009-02-18 14:48:16 -0800296 else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 *ppos += copied;
Eric Biederman8f19d472009-02-18 14:48:16 -0800298 m->read_pos += copied;
299 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 file->f_version = m->version;
Ingo Molnar0ac17592006-03-23 03:00:37 -0800301 mutex_unlock(&m->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 return copied;
303Enomem:
304 err = -ENOMEM;
305 goto Done;
306Efault:
307 err = -EFAULT;
308 goto Done;
309}
310EXPORT_SYMBOL(seq_read);
311
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312/**
313 * seq_lseek - ->llseek() method for sequential files.
Martin Waitz67be2dd2005-05-01 08:59:26 -0700314 * @file: the file in question
315 * @offset: new position
Randy Dunlap254adaa2013-01-09 17:13:00 -0800316 * @whence: 0 for absolute, 1 for relative position
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 *
318 * Ready-made ->f_op->llseek()
319 */
Andrew Morton965c8e52012-12-17 15:59:39 -0800320loff_t seq_lseek(struct file *file, loff_t offset, int whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321{
Joe Perches8209e2f2010-09-04 18:52:49 -0700322 struct seq_file *m = file->private_data;
David Sterba16abef02008-04-22 15:09:22 +0200323 loff_t retval = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324
Ingo Molnar0ac17592006-03-23 03:00:37 -0800325 mutex_lock(&m->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 m->version = file->f_version;
Andrew Morton965c8e52012-12-17 15:59:39 -0800327 switch (whence) {
Andrew Morton5e62ade2013-02-27 17:03:22 -0800328 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 /* with extreme prejudice... */
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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 }
Gu Zheng05e16742013-10-25 18:15:06 +0800348 } else {
349 file->f_pos = offset;
Andrew Morton5e62ade2013-02-27 17:03:22 -0800350 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 file->f_version = m->version;
Alexey Dobriyan00c57462007-07-15 23:40:22 -0700353 mutex_unlock(&m->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 return retval;
355}
356EXPORT_SYMBOL(seq_lseek);
357
358/**
359 * seq_release - free the structures associated with sequential file.
360 * @file: file in question
Al Viro6131ffa2013-02-27 16:59:05 -0500361 * @inode: its inode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 *
363 * Frees the structures associated with sequential file; can be used
364 * as ->f_op->release() if you don't have private data to destroy.
365 */
366int seq_release(struct inode *inode, struct file *file)
367{
Joe Perches8209e2f2010-09-04 18:52:49 -0700368 struct seq_file *m = file->private_data;
Heiko Carstens058504e2014-07-02 15:22:37 -0700369 kvfree(m->buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 kfree(m);
371 return 0;
372}
373EXPORT_SYMBOL(seq_release);
374
375/**
376 * seq_escape - print string into buffer, escaping some characters
377 * @m: target buffer
378 * @s: string
379 * @esc: set of characters that need escaping
380 *
381 * Puts string into buffer, replacing each occurrence of character from
Joe Perches6798a8c2015-09-11 13:07:48 -0700382 * @esc with usual octal escape.
383 * Use seq_has_overflowed() to check for errors.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 */
Joe Perches6798a8c2015-09-11 13:07:48 -0700385void seq_escape(struct seq_file *m, const char *s, const char *esc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386{
Andy Shevchenko25c6bb76e2015-11-06 16:32:40 -0800387 char *buf;
388 size_t size = seq_get_buf(m, &buf);
389 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390
Andy Shevchenko25c6bb76e2015-11-06 16:32:40 -0800391 ret = string_escape_str(s, buf, size, ESCAPE_OCTAL, esc);
392 seq_commit(m, ret < size ? ret : -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393}
394EXPORT_SYMBOL(seq_escape);
395
Joe Perches6798a8c2015-09-11 13:07:48 -0700396void seq_vprintf(struct seq_file *m, const char *f, va_list args)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398 int len;
399
400 if (m->count < m->size) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 if (m->count + len < m->size) {
403 m->count += len;
Joe Perches6798a8c2015-09-11 13:07:48 -0700404 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 }
406 }
KAMEZAWA Hiroyukie075f592012-03-23 15:02:55 -0700407 seq_set_overflow(m);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408}
Steven Whitehousea4808142012-06-11 13:16:35 +0100409EXPORT_SYMBOL(seq_vprintf);
410
Joe Perches6798a8c2015-09-11 13:07:48 -0700411void seq_printf(struct seq_file *m, const char *f, ...)
Steven Whitehousea4808142012-06-11 13:16:35 +0100412{
Steven Whitehousea4808142012-06-11 13:16:35 +0100413 va_list args;
414
415 va_start(args, f);
Joe Perches6798a8c2015-09-11 13:07:48 -0700416 seq_vprintf(m, f, args);
Steven Whitehousea4808142012-06-11 13:16:35 +0100417 va_end(args);
Steven Whitehousea4808142012-06-11 13:16:35 +0100418}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419EXPORT_SYMBOL(seq_printf);
420
Török Edwin74e2f332008-11-22 13:28:48 +0200421/**
Török Edwin958086d2008-11-23 23:24:53 +0200422 * mangle_path - mangle and copy path to buffer beginning
423 * @s: buffer start
424 * @p: beginning of path in above buffer
425 * @esc: set of characters that need escaping
Török Edwin74e2f332008-11-22 13:28:48 +0200426 *
427 * Copy the path from @p to @s, replacing each occurrence of character from
428 * @esc with usual octal escape.
429 * Returns pointer past last written character in @s, or NULL in case of
430 * failure.
431 */
Al Viro8c9379e2011-12-08 20:18:57 -0500432char *mangle_path(char *s, const char *p, const char *esc)
Ram Pai6092d042008-03-27 13:06:20 +0100433{
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}
Ingo Molnar604094f2008-11-28 18:03:22 +0100451EXPORT_SYMBOL(mangle_path);
Ram Pai6092d042008-03-27 13:06:20 +0100452
Arjan van de Ven52afeef2008-12-01 14:35:00 -0800453/**
454 * seq_path - seq_file interface to print a pathname
455 * @m: the seq_file handle
456 * @path: the struct path to print
457 * @esc: set of characters to escape in the output
458 *
459 * return the absolute path of 'path', as represented by the
460 * dentry / mnt pair in the path parameter.
Ram Pai6092d042008-03-27 13:06:20 +0100461 */
Al Viro8c9379e2011-12-08 20:18:57 -0500462int seq_path(struct seq_file *m, const struct path *path, const char *esc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463{
Miklos Szeredif8439802009-09-21 14:48:36 +0200464 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 if (!IS_ERR(p)) {
Miklos Szeredif8439802009-09-21 14:48:36 +0200471 char *end = mangle_path(buf, p, esc);
472 if (end)
473 res = end - buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474 }
475 }
Miklos Szeredif8439802009-09-21 14:48:36 +0200476 seq_commit(m, res);
477
478 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479}
480EXPORT_SYMBOL(seq_path);
481
Miklos Szeredi2726d562015-06-19 10:30:28 +0200482/**
483 * seq_file_path - seq_file interface to print a pathname of a file
484 * @m: the seq_file handle
485 * @file: the struct file to print
486 * @esc: set of characters to escape in the output
487 *
488 * return the absolute path to the file.
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
Ram Pai6092d042008-03-27 13:06:20 +0100496/*
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100497 * Same as seq_path, but relative to supplied root.
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100498 */
Al Viro8c9379e2011-12-08 20:18:57 -0500499int seq_path_root(struct seq_file *m, const struct path *path,
500 const struct path *root, const char *esc)
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100501{
Miklos Szeredif8439802009-09-21 14:48:36 +0200502 char *buf;
503 size_t size = seq_get_buf(m, &buf);
504 int res = -ENAMETOOLONG;
505
506 if (size) {
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100507 char *p;
508
Miklos Szeredif8439802009-09-21 14:48:36 +0200509 p = __d_path(path, root, buf, size);
Al Viro02125a82011-12-05 08:43:34 -0500510 if (!p)
511 return SEQ_SKIP;
Miklos Szeredif8439802009-09-21 14:48:36 +0200512 res = PTR_ERR(p);
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100513 if (!IS_ERR(p)) {
Miklos Szeredif8439802009-09-21 14:48:36 +0200514 char *end = mangle_path(buf, p, esc);
515 if (end)
516 res = end - buf;
517 else
518 res = -ENAMETOOLONG;
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100519 }
520 }
Miklos Szeredif8439802009-09-21 14:48:36 +0200521 seq_commit(m, res);
522
Al Viro02125a82011-12-05 08:43:34 -0500523 return res < 0 && res != -ENAMETOOLONG ? res : 0;
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100524}
525
526/*
Ram Pai6092d042008-03-27 13:06:20 +0100527 * returns the path of the 'dentry' from the root of its filesystem.
528 */
Al Viro8c9379e2011-12-08 20:18:57 -0500529int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc)
Ram Pai6092d042008-03-27 13:06:20 +0100530{
Miklos Szeredif8439802009-09-21 14:48:36 +0200531 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);
Ram Pai6092d042008-03-27 13:06:20 +0100537 if (!IS_ERR(p)) {
Miklos Szeredif8439802009-09-21 14:48:36 +0200538 char *end = mangle_path(buf, p, esc);
539 if (end)
540 res = end - buf;
Ram Pai6092d042008-03-27 13:06:20 +0100541 }
542 }
Miklos Szeredif8439802009-09-21 14:48:36 +0200543 seq_commit(m, res);
544
545 return res;
Ram Pai6092d042008-03-27 13:06:20 +0100546}
Omar Sandovalc8d3fe02015-05-18 02:16:31 -0700547EXPORT_SYMBOL(seq_dentry);
Ram Pai6092d042008-03-27 13:06:20 +0100548
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549static 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
Al Viro2043f492013-03-31 13:43:23 -0400585int single_open_size(struct file *file, int (*show)(struct seq_file *, void *),
586 void *data, size_t size)
587{
Heiko Carstens058504e2014-07-02 15:22:37 -0700588 char *buf = seq_buf_alloc(size);
Al Viro2043f492013-03-31 13:43:23 -0400589 int ret;
590 if (!buf)
591 return -ENOMEM;
592 ret = single_open(file, show, data);
593 if (ret) {
Heiko Carstens058504e2014-07-02 15:22:37 -0700594 kvfree(buf);
Al Viro2043f492013-03-31 13:43:23 -0400595 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603int single_release(struct inode *inode, struct file *file)
604{
Helge Deller15ad7cd2006-12-06 20:40:36 -0800605 const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 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
Pavel Emelyanov39699032007-10-10 02:28:42 -0700622void *__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
Joe Perches6798a8c2015-09-11 13:07:48 -0700655void seq_putc(struct seq_file *m, char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656{
Joe Perches6798a8c2015-09-11 13:07:48 -0700657 if (m->count >= m->size)
658 return;
659
660 m->buf[m->count++] = c;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661}
662EXPORT_SYMBOL(seq_putc);
663
Joe Perches6798a8c2015-09-11 13:07:48 -0700664void seq_puts(struct seq_file *m, const char *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665{
666 int len = strlen(s);
Joe Perches6798a8c2015-09-11 13:07:48 -0700667
668 if (m->count + len >= m->size) {
669 seq_set_overflow(m);
670 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 }
Joe Perches6798a8c2015-09-11 13:07:48 -0700672 memcpy(m->buf + m->count, s, len);
673 m->count += len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674}
675EXPORT_SYMBOL(seq_puts);
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700676
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700677/*
678 * A helper routine for putting decimal numbers without rich format of printf().
679 * only 'unsigned long long' is supported.
680 * This routine will put one byte delimiter + number into seq_file.
681 * This routine is very quick when you show lots of numbers.
682 * In usual cases, it will be better to use seq_printf(). It's easier to read.
683 */
Joe Perches6798a8c2015-09-11 13:07:48 -0700684void seq_put_decimal_ull(struct seq_file *m, char delimiter,
685 unsigned long long num)
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700686{
687 int len;
688
689 if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */
690 goto overflow;
691
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700692 if (delimiter)
693 m->buf[m->count++] = delimiter;
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700694
695 if (num < 10) {
696 m->buf[m->count++] = num + '0';
Joe Perches6798a8c2015-09-11 13:07:48 -0700697 return;
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700698 }
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;
Joe Perches6798a8c2015-09-11 13:07:48 -0700704 return;
705
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700706overflow:
KAMEZAWA Hiroyukie075f592012-03-23 15:02:55 -0700707 seq_set_overflow(m);
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700708}
709EXPORT_SYMBOL(seq_put_decimal_ull);
710
Joe Perches6798a8c2015-09-11 13:07:48 -0700711void seq_put_decimal_ll(struct seq_file *m, char delimiter, long long num)
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700712{
713 if (num < 0) {
714 if (m->count + 3 >= m->size) {
KAMEZAWA Hiroyukie075f592012-03-23 15:02:55 -0700715 seq_set_overflow(m);
Joe Perches6798a8c2015-09-11 13:07:48 -0700716 return;
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700717 }
718 if (delimiter)
719 m->buf[m->count++] = delimiter;
720 num = -num;
721 delimiter = '-';
722 }
Joe Perches6798a8c2015-09-11 13:07:48 -0700723 seq_put_decimal_ull(m, delimiter, num);
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700724}
725EXPORT_SYMBOL(seq_put_decimal_ll);
726
Peter Oberparleiter0b923602009-06-17 16:28:05 -0700727/**
728 * seq_write - write arbitrary data to buffer
729 * @seq: seq_file identifying the buffer to which data should be written
730 * @data: data address
731 * @len: number of bytes
732 *
733 * Return 0 on success, non-zero otherwise.
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 }
KAMEZAWA Hiroyukie075f592012-03-23 15:02:55 -0700742 seq_set_overflow(seq);
Peter Oberparleiter0b923602009-06-17 16:28:05 -0700743 return -1;
744}
745EXPORT_SYMBOL(seq_write);
746
Tetsuo Handa839cc2a2013-11-14 14:31:56 -0800747/**
748 * seq_pad - write padding spaces to buffer
749 * @m: seq_file identifying the buffer to which data should be written
750 * @c: the byte to append after padding if non-zero
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
Andy Shevchenko37607102015-09-09 15:38:33 -0700762/* A complete analogue of print_hex_dump() */
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;
Andy Shevchenko8b91a312015-11-06 16:32:37 -0800769 char *buffer;
770 size_t size;
Andy Shevchenko37607102015-09-09 15:38:33 -0700771 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
Andy Shevchenko8b91a312015-11-06 16:32:37 -0800792 size = seq_get_buf(m, &buffer);
Andy Shevchenko37607102015-09-09 15:38:33 -0700793 ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
Andy Shevchenko8b91a312015-11-06 16:32:37 -0800794 buffer, size, ascii);
795 seq_commit(m, ret < size ? ret : -1);
796
797 seq_putc(m, '\n');
Andy Shevchenko37607102015-09-09 15:38:33 -0700798 }
799}
800EXPORT_SYMBOL(seq_hex_dump);
801
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700802struct 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}
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700812EXPORT_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}
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700821EXPORT_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}
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700831EXPORT_SYMBOL(seq_list_next);
Li Zefan66655de2010-02-08 23:18:22 +0000832
833/**
834 * seq_hlist_start - start an iteration of a hlist
835 * @head: the head of the hlist
836 * @pos: the start position of the sequence
837 *
838 * Called at seq_file->op->start().
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 * seq_hlist_start_head - start an iteration of a hlist
853 * @head: the head of the hlist
854 * @pos: the start position of the sequence
855 *
856 * Called at seq_file->op->start(). Call this function if you want to
857 * print a header at the top of the output.
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 * seq_hlist_next - move to the next position of the hlist
870 * @v: the current iterator
871 * @head: the head of the hlist
Randy Dunlap138860b2010-03-04 09:37:12 -0800872 * @ppos: the current position
Li Zefan66655de2010-02-08 23:18:22 +0000873 *
874 * Called at seq_file->op->next().
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);
stephen hemminger1cc52322010-02-22 07:57:17 +0000888
889/**
890 * seq_hlist_start_rcu - start an iteration of a hlist protected by RCU
891 * @head: the head of the hlist
892 * @pos: the start position of the sequence
893 *
894 * Called at seq_file->op->start().
895 *
896 * This list-traversal primitive may safely run concurrently with
897 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
898 * as long as the traversal is guarded by rcu_read_lock().
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 * seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU
914 * @head: the head of the hlist
915 * @pos: the start position of the sequence
916 *
917 * Called at seq_file->op->start(). Call this function if you want to
918 * print a header at the top of the output.
919 *
920 * This list-traversal primitive may safely run concurrently with
921 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
922 * as long as the traversal is guarded by rcu_read_lock().
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 * seq_hlist_next_rcu - move to the next position of the hlist protected by RCU
936 * @v: the current iterator
937 * @head: the head of the hlist
Randy Dunlap138860b2010-03-04 09:37:12 -0800938 * @ppos: the current position
stephen hemminger1cc52322010-02-22 07:57:17 +0000939 *
940 * Called at seq_file->op->next().
941 *
942 * This list-traversal primitive may safely run concurrently with
943 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
944 * as long as the traversal is guarded by rcu_read_lock().
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);
Jeff Layton0bc77382013-06-21 08:58:21 -0400959
960/**
961 * seq_hlist_start_precpu - start an iteration of a percpu hlist array
962 * @head: pointer to percpu array of struct hlist_heads
963 * @cpu: pointer to cpu "cursor"
964 * @pos: start position of sequence
965 *
966 * Called at seq_file->op->start().
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 * seq_hlist_next_percpu - move to the next position of the percpu hlist array
985 * @v: pointer to current hlist_node
986 * @head: pointer to percpu array of struct hlist_heads
987 * @cpu: pointer to cpu "cursor"
988 * @pos: start position of sequence
989 *
990 * Called at seq_file->op->next().
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);