blob: e85664b7c7d963522fd7efc938a3d96a27edc651 [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 Shevchenko25c6bb72015-11-06 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;
Eric W. Biedermanadb37c42012-05-23 18:01:20 -060075#ifdef CONFIG_USER_NS
76 p->user_ns = file->f_cred->user_ns;
77#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
79 /*
80 * Wrappers around seq_open(e.g. swaps_open) need to be
81 * aware of this. If they set f_version themselves, they
82 * should call seq_open first and then set f_version.
83 */
84 file->f_version = 0;
85
Eric Biederman8f19d472009-02-18 14:48:16 -080086 /*
87 * seq_files support lseek() and pread(). They do not implement
88 * write() at all, but we clear FMODE_PWRITE here for historical
89 * reasons.
90 *
91 * If a client of seq_files a) implements file.write() and b) wishes to
92 * support pwrite() then that client will need to implement its own
93 * file.open() which calls seq_open() and then sets FMODE_PWRITE.
94 */
95 file->f_mode &= ~FMODE_PWRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 return 0;
97}
98EXPORT_SYMBOL(seq_open);
99
Eric Biederman33da8892009-02-04 15:12:25 -0800100static int traverse(struct seq_file *m, loff_t offset)
101{
102 loff_t pos = 0, index;
103 int error = 0;
104 void *p;
105
106 m->version = 0;
107 index = 0;
108 m->count = m->from = 0;
109 if (!offset) {
110 m->index = index;
111 return 0;
112 }
113 if (!m->buf) {
Heiko Carstens058504e2014-07-02 15:22:37 -0700114 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
Eric Biederman33da8892009-02-04 15:12:25 -0800115 if (!m->buf)
116 return -ENOMEM;
117 }
118 p = m->op->start(m, &index);
119 while (p) {
120 error = PTR_ERR(p);
121 if (IS_ERR(p))
122 break;
123 error = m->op->show(m, p);
124 if (error < 0)
125 break;
126 if (unlikely(error)) {
127 error = 0;
128 m->count = 0;
129 }
Joe Perches1f33c412014-09-29 16:08:21 -0700130 if (seq_has_overflowed(m))
Eric Biederman33da8892009-02-04 15:12:25 -0800131 goto Eoverflow;
132 if (pos + m->count > offset) {
133 m->from = offset - pos;
134 m->count -= m->from;
135 m->index = index;
136 break;
137 }
138 pos += m->count;
139 m->count = 0;
140 if (pos == offset) {
141 index++;
142 m->index = index;
143 break;
144 }
145 p = m->op->next(m, p, &index);
146 }
147 m->op->stop(m, p);
Alexey Dobriyanf01d1d52009-02-06 00:30:05 +0300148 m->index = index;
Eric Biederman33da8892009-02-04 15:12:25 -0800149 return error;
150
151Eoverflow:
152 m->op->stop(m, p);
Heiko Carstens058504e2014-07-02 15:22:37 -0700153 kvfree(m->buf);
Al Viro801a7602013-11-19 01:20:43 +0000154 m->count = 0;
Heiko Carstens058504e2014-07-02 15:22:37 -0700155 m->buf = seq_buf_alloc(m->size <<= 1);
Eric Biederman33da8892009-02-04 15:12:25 -0800156 return !m->buf ? -ENOMEM : -EAGAIN;
157}
158
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159/**
160 * seq_read - ->read() method for sequential files.
Martin Waitz67be2dd2005-05-01 08:59:26 -0700161 * @file: the file to read from
162 * @buf: the buffer to read to
163 * @size: the maximum number of bytes to read
164 * @ppos: the current position in the file
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 *
166 * Ready-made ->f_op->read()
167 */
168ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
169{
Joe Perches8209e2f2010-09-04 18:52:49 -0700170 struct seq_file *m = file->private_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 size_t copied = 0;
172 loff_t pos;
173 size_t n;
174 void *p;
175 int err = 0;
176
Ingo Molnar0ac17592006-03-23 03:00:37 -0800177 mutex_lock(&m->lock);
Eric Biederman8f19d472009-02-18 14:48:16 -0800178
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 /*
180 * seq_file->op->..m_start/m_stop/m_next may do special actions
181 * or optimisations based on the file->f_version, so we want to
182 * pass the file->f_version to those methods.
183 *
184 * seq_file->version is just copy of f_version, and seq_file
185 * methods can treat it simply as file version.
186 * It is copied in first and copied out after all operations.
187 * It is convenient to have it as part of structure to avoid the
188 * need of passing another argument to all the seq_file methods.
189 */
190 m->version = file->f_version;
Earl Chew7904ac82012-03-21 16:33:43 -0700191
192 /* Don't assume *ppos is where we left it */
193 if (unlikely(*ppos != m->read_pos)) {
194 while ((err = traverse(m, *ppos)) == -EAGAIN)
195 ;
196 if (err) {
197 /* With prejudice... */
198 m->read_pos = 0;
199 m->version = 0;
200 m->index = 0;
201 m->count = 0;
202 goto Done;
203 } else {
204 m->read_pos = *ppos;
205 }
206 }
207
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 /* grab buffer if we didn't have one */
209 if (!m->buf) {
Heiko Carstens058504e2014-07-02 15:22:37 -0700210 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 if (!m->buf)
212 goto Enomem;
213 }
214 /* if not empty - flush it first */
215 if (m->count) {
216 n = min(m->count, size);
217 err = copy_to_user(buf, m->buf + m->from, n);
218 if (err)
219 goto Efault;
220 m->count -= n;
221 m->from += n;
222 size -= n;
223 buf += n;
224 copied += n;
225 if (!m->count)
226 m->index++;
227 if (!size)
228 goto Done;
229 }
230 /* we need at least one record in buffer */
Al Viro4cdfe842008-08-24 07:45:33 -0400231 pos = m->index;
232 p = m->op->start(m, &pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 while (1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 err = PTR_ERR(p);
235 if (!p || IS_ERR(p))
236 break;
237 err = m->op->show(m, p);
Al Viro521b5d02008-03-28 00:46:41 -0400238 if (err < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 break;
Al Viro521b5d02008-03-28 00:46:41 -0400240 if (unlikely(err))
241 m->count = 0;
Al Viro4cdfe842008-08-24 07:45:33 -0400242 if (unlikely(!m->count)) {
243 p = m->op->next(m, p, &pos);
244 m->index = pos;
245 continue;
246 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 if (m->count < m->size)
248 goto Fill;
249 m->op->stop(m, p);
Heiko Carstens058504e2014-07-02 15:22:37 -0700250 kvfree(m->buf);
Al Viro801a7602013-11-19 01:20:43 +0000251 m->count = 0;
Heiko Carstens058504e2014-07-02 15:22:37 -0700252 m->buf = seq_buf_alloc(m->size <<= 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 if (!m->buf)
254 goto Enomem;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 m->version = 0;
Al Viro4cdfe842008-08-24 07:45:33 -0400256 pos = m->index;
257 p = m->op->start(m, &pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 }
259 m->op->stop(m, p);
260 m->count = 0;
261 goto Done;
262Fill:
263 /* they want more? let's try to get some more */
264 while (m->count < size) {
265 size_t offs = m->count;
266 loff_t next = pos;
267 p = m->op->next(m, p, &next);
268 if (!p || IS_ERR(p)) {
269 err = PTR_ERR(p);
270 break;
271 }
272 err = m->op->show(m, p);
Joe Perches1f33c412014-09-29 16:08:21 -0700273 if (seq_has_overflowed(m) || err) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 m->count = offs;
Al Viro521b5d02008-03-28 00:46:41 -0400275 if (likely(err <= 0))
276 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 }
278 pos = next;
279 }
280 m->op->stop(m, p);
281 n = min(m->count, size);
282 err = copy_to_user(buf, m->buf, n);
283 if (err)
284 goto Efault;
285 copied += n;
286 m->count -= n;
287 if (m->count)
288 m->from = n;
289 else
290 pos++;
291 m->index = pos;
292Done:
293 if (!copied)
294 copied = err;
Eric Biederman8f19d472009-02-18 14:48:16 -0800295 else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 *ppos += copied;
Eric Biederman8f19d472009-02-18 14:48:16 -0800297 m->read_pos += copied;
298 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 file->f_version = m->version;
Ingo Molnar0ac17592006-03-23 03:00:37 -0800300 mutex_unlock(&m->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 return copied;
302Enomem:
303 err = -ENOMEM;
304 goto Done;
305Efault:
306 err = -EFAULT;
307 goto Done;
308}
309EXPORT_SYMBOL(seq_read);
310
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311/**
312 * seq_lseek - ->llseek() method for sequential files.
Martin Waitz67be2dd2005-05-01 08:59:26 -0700313 * @file: the file in question
314 * @offset: new position
Randy Dunlap254adaa2013-01-09 17:13:00 -0800315 * @whence: 0 for absolute, 1 for relative position
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 *
317 * Ready-made ->f_op->llseek()
318 */
Andrew Morton965c8e52012-12-17 15:59:39 -0800319loff_t seq_lseek(struct file *file, loff_t offset, int whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320{
Joe Perches8209e2f2010-09-04 18:52:49 -0700321 struct seq_file *m = file->private_data;
David Sterba16abef02008-04-22 15:09:22 +0200322 loff_t retval = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323
Ingo Molnar0ac17592006-03-23 03:00:37 -0800324 mutex_lock(&m->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 m->version = file->f_version;
Andrew Morton965c8e52012-12-17 15:59:39 -0800326 switch (whence) {
Andrew Morton5e62ade2013-02-27 17:03:22 -0800327 case SEEK_CUR:
328 offset += file->f_pos;
329 case SEEK_SET:
330 if (offset < 0)
331 break;
332 retval = offset;
333 if (offset != m->read_pos) {
334 while ((retval = traverse(m, offset)) == -EAGAIN)
335 ;
336 if (retval) {
337 /* with extreme prejudice... */
338 file->f_pos = 0;
339 m->read_pos = 0;
340 m->version = 0;
341 m->index = 0;
342 m->count = 0;
343 } else {
344 m->read_pos = offset;
345 retval = file->f_pos = offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 }
Gu Zheng05e16742013-10-25 18:15:06 +0800347 } else {
348 file->f_pos = offset;
Andrew Morton5e62ade2013-02-27 17:03:22 -0800349 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 file->f_version = m->version;
Alexey Dobriyan00c57462007-07-15 23:40:22 -0700352 mutex_unlock(&m->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 return retval;
354}
355EXPORT_SYMBOL(seq_lseek);
356
357/**
358 * seq_release - free the structures associated with sequential file.
359 * @file: file in question
Al Viro6131ffa2013-02-27 16:59:05 -0500360 * @inode: its inode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 *
362 * Frees the structures associated with sequential file; can be used
363 * as ->f_op->release() if you don't have private data to destroy.
364 */
365int seq_release(struct inode *inode, struct file *file)
366{
Joe Perches8209e2f2010-09-04 18:52:49 -0700367 struct seq_file *m = file->private_data;
Heiko Carstens058504e2014-07-02 15:22:37 -0700368 kvfree(m->buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 kfree(m);
370 return 0;
371}
372EXPORT_SYMBOL(seq_release);
373
374/**
375 * seq_escape - print string into buffer, escaping some characters
376 * @m: target buffer
377 * @s: string
378 * @esc: set of characters that need escaping
379 *
380 * Puts string into buffer, replacing each occurrence of character from
Joe Perches6798a8c2015-09-11 13:07:48 -0700381 * @esc with usual octal escape.
382 * Use seq_has_overflowed() to check for errors.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 */
Joe Perches6798a8c2015-09-11 13:07:48 -0700384void seq_escape(struct seq_file *m, const char *s, const char *esc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385{
Andy Shevchenko25c6bb72015-11-06 16:32:40 -0800386 char *buf;
387 size_t size = seq_get_buf(m, &buf);
388 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389
Andy Shevchenko25c6bb72015-11-06 16:32:40 -0800390 ret = string_escape_str(s, buf, size, ESCAPE_OCTAL, esc);
391 seq_commit(m, ret < size ? ret : -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392}
393EXPORT_SYMBOL(seq_escape);
394
Joe Perches6798a8c2015-09-11 13:07:48 -0700395void seq_vprintf(struct seq_file *m, const char *f, va_list args)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 int len;
398
399 if (m->count < m->size) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 if (m->count + len < m->size) {
402 m->count += len;
Joe Perches6798a8c2015-09-11 13:07:48 -0700403 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 }
405 }
KAMEZAWA Hiroyukie075f592012-03-23 15:02:55 -0700406 seq_set_overflow(m);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407}
Steven Whitehousea4808142012-06-11 13:16:35 +0100408EXPORT_SYMBOL(seq_vprintf);
409
Joe Perches6798a8c2015-09-11 13:07:48 -0700410void seq_printf(struct seq_file *m, const char *f, ...)
Steven Whitehousea4808142012-06-11 13:16:35 +0100411{
Steven Whitehousea4808142012-06-11 13:16:35 +0100412 va_list args;
413
414 va_start(args, f);
Joe Perches6798a8c2015-09-11 13:07:48 -0700415 seq_vprintf(m, f, args);
Steven Whitehousea4808142012-06-11 13:16:35 +0100416 va_end(args);
Steven Whitehousea4808142012-06-11 13:16:35 +0100417}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418EXPORT_SYMBOL(seq_printf);
419
Török Edwin74e2f332008-11-22 13:28:48 +0200420/**
Török Edwin958086d2008-11-23 23:24:53 +0200421 * mangle_path - mangle and copy path to buffer beginning
422 * @s: buffer start
423 * @p: beginning of path in above buffer
424 * @esc: set of characters that need escaping
Török Edwin74e2f332008-11-22 13:28:48 +0200425 *
426 * Copy the path from @p to @s, replacing each occurrence of character from
427 * @esc with usual octal escape.
428 * Returns pointer past last written character in @s, or NULL in case of
429 * failure.
430 */
Al Viro8c9379e2011-12-08 20:18:57 -0500431char *mangle_path(char *s, const char *p, const char *esc)
Ram Pai6092d042008-03-27 13:06:20 +0100432{
433 while (s <= p) {
434 char c = *p++;
435 if (!c) {
436 return s;
437 } else if (!strchr(esc, c)) {
438 *s++ = c;
439 } else if (s + 4 > p) {
440 break;
441 } else {
442 *s++ = '\\';
443 *s++ = '0' + ((c & 0300) >> 6);
444 *s++ = '0' + ((c & 070) >> 3);
445 *s++ = '0' + (c & 07);
446 }
447 }
448 return NULL;
449}
Ingo Molnar604094f2008-11-28 18:03:22 +0100450EXPORT_SYMBOL(mangle_path);
Ram Pai6092d042008-03-27 13:06:20 +0100451
Arjan van de Ven52afeef2008-12-01 14:35:00 -0800452/**
453 * seq_path - seq_file interface to print a pathname
454 * @m: the seq_file handle
455 * @path: the struct path to print
456 * @esc: set of characters to escape in the output
457 *
458 * return the absolute path of 'path', as represented by the
459 * dentry / mnt pair in the path parameter.
Ram Pai6092d042008-03-27 13:06:20 +0100460 */
Al Viro8c9379e2011-12-08 20:18:57 -0500461int seq_path(struct seq_file *m, const struct path *path, const char *esc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462{
Miklos Szeredif8439802009-09-21 14:48:36 +0200463 char *buf;
464 size_t size = seq_get_buf(m, &buf);
465 int res = -1;
466
467 if (size) {
468 char *p = d_path(path, buf, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 if (!IS_ERR(p)) {
Miklos Szeredif8439802009-09-21 14:48:36 +0200470 char *end = mangle_path(buf, p, esc);
471 if (end)
472 res = end - buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 }
474 }
Miklos Szeredif8439802009-09-21 14:48:36 +0200475 seq_commit(m, res);
476
477 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478}
479EXPORT_SYMBOL(seq_path);
480
Miklos Szeredi2726d562015-06-19 10:30:28 +0200481/**
482 * seq_file_path - seq_file interface to print a pathname of a file
483 * @m: the seq_file handle
484 * @file: the struct file to print
485 * @esc: set of characters to escape in the output
486 *
487 * return the absolute path to the file.
488 */
489int seq_file_path(struct seq_file *m, struct file *file, const char *esc)
490{
491 return seq_path(m, &file->f_path, esc);
492}
493EXPORT_SYMBOL(seq_file_path);
494
Ram Pai6092d042008-03-27 13:06:20 +0100495/*
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100496 * Same as seq_path, but relative to supplied root.
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100497 */
Al Viro8c9379e2011-12-08 20:18:57 -0500498int seq_path_root(struct seq_file *m, const struct path *path,
499 const struct path *root, const char *esc)
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100500{
Miklos Szeredif8439802009-09-21 14:48:36 +0200501 char *buf;
502 size_t size = seq_get_buf(m, &buf);
503 int res = -ENAMETOOLONG;
504
505 if (size) {
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100506 char *p;
507
Miklos Szeredif8439802009-09-21 14:48:36 +0200508 p = __d_path(path, root, buf, size);
Al Viro02125a82011-12-05 08:43:34 -0500509 if (!p)
510 return SEQ_SKIP;
Miklos Szeredif8439802009-09-21 14:48:36 +0200511 res = PTR_ERR(p);
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100512 if (!IS_ERR(p)) {
Miklos Szeredif8439802009-09-21 14:48:36 +0200513 char *end = mangle_path(buf, p, esc);
514 if (end)
515 res = end - buf;
516 else
517 res = -ENAMETOOLONG;
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100518 }
519 }
Miklos Szeredif8439802009-09-21 14:48:36 +0200520 seq_commit(m, res);
521
Al Viro02125a82011-12-05 08:43:34 -0500522 return res < 0 && res != -ENAMETOOLONG ? res : 0;
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100523}
524
525/*
Ram Pai6092d042008-03-27 13:06:20 +0100526 * returns the path of the 'dentry' from the root of its filesystem.
527 */
Al Viro8c9379e2011-12-08 20:18:57 -0500528int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc)
Ram Pai6092d042008-03-27 13:06:20 +0100529{
Miklos Szeredif8439802009-09-21 14:48:36 +0200530 char *buf;
531 size_t size = seq_get_buf(m, &buf);
532 int res = -1;
533
534 if (size) {
535 char *p = dentry_path(dentry, buf, size);
Ram Pai6092d042008-03-27 13:06:20 +0100536 if (!IS_ERR(p)) {
Miklos Szeredif8439802009-09-21 14:48:36 +0200537 char *end = mangle_path(buf, p, esc);
538 if (end)
539 res = end - buf;
Ram Pai6092d042008-03-27 13:06:20 +0100540 }
541 }
Miklos Szeredif8439802009-09-21 14:48:36 +0200542 seq_commit(m, res);
543
544 return res;
Ram Pai6092d042008-03-27 13:06:20 +0100545}
Omar Sandovalc8d3fe02015-05-18 02:16:31 -0700546EXPORT_SYMBOL(seq_dentry);
Ram Pai6092d042008-03-27 13:06:20 +0100547
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548static void *single_start(struct seq_file *p, loff_t *pos)
549{
550 return NULL + (*pos == 0);
551}
552
553static void *single_next(struct seq_file *p, void *v, loff_t *pos)
554{
555 ++*pos;
556 return NULL;
557}
558
559static void single_stop(struct seq_file *p, void *v)
560{
561}
562
563int single_open(struct file *file, int (*show)(struct seq_file *, void *),
564 void *data)
565{
566 struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL);
567 int res = -ENOMEM;
568
569 if (op) {
570 op->start = single_start;
571 op->next = single_next;
572 op->stop = single_stop;
573 op->show = show;
574 res = seq_open(file, op);
575 if (!res)
576 ((struct seq_file *)file->private_data)->private = data;
577 else
578 kfree(op);
579 }
580 return res;
581}
582EXPORT_SYMBOL(single_open);
583
Al Viro2043f492013-03-31 13:43:23 -0400584int single_open_size(struct file *file, int (*show)(struct seq_file *, void *),
585 void *data, size_t size)
586{
Heiko Carstens058504e2014-07-02 15:22:37 -0700587 char *buf = seq_buf_alloc(size);
Al Viro2043f492013-03-31 13:43:23 -0400588 int ret;
589 if (!buf)
590 return -ENOMEM;
591 ret = single_open(file, show, data);
592 if (ret) {
Heiko Carstens058504e2014-07-02 15:22:37 -0700593 kvfree(buf);
Al Viro2043f492013-03-31 13:43:23 -0400594 return ret;
595 }
596 ((struct seq_file *)file->private_data)->buf = buf;
597 ((struct seq_file *)file->private_data)->size = size;
598 return 0;
599}
600EXPORT_SYMBOL(single_open_size);
601
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602int single_release(struct inode *inode, struct file *file)
603{
Helge Deller15ad7cd2006-12-06 20:40:36 -0800604 const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 int res = seq_release(inode, file);
606 kfree(op);
607 return res;
608}
609EXPORT_SYMBOL(single_release);
610
611int seq_release_private(struct inode *inode, struct file *file)
612{
613 struct seq_file *seq = file->private_data;
614
615 kfree(seq->private);
616 seq->private = NULL;
617 return seq_release(inode, file);
618}
619EXPORT_SYMBOL(seq_release_private);
620
Pavel Emelyanov39699032007-10-10 02:28:42 -0700621void *__seq_open_private(struct file *f, const struct seq_operations *ops,
622 int psize)
623{
624 int rc;
625 void *private;
626 struct seq_file *seq;
627
628 private = kzalloc(psize, GFP_KERNEL);
629 if (private == NULL)
630 goto out;
631
632 rc = seq_open(f, ops);
633 if (rc < 0)
634 goto out_free;
635
636 seq = f->private_data;
637 seq->private = private;
638 return private;
639
640out_free:
641 kfree(private);
642out:
643 return NULL;
644}
645EXPORT_SYMBOL(__seq_open_private);
646
647int seq_open_private(struct file *filp, const struct seq_operations *ops,
648 int psize)
649{
650 return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;
651}
652EXPORT_SYMBOL(seq_open_private);
653
Joe Perches6798a8c2015-09-11 13:07:48 -0700654void seq_putc(struct seq_file *m, char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655{
Joe Perches6798a8c2015-09-11 13:07:48 -0700656 if (m->count >= m->size)
657 return;
658
659 m->buf[m->count++] = c;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660}
661EXPORT_SYMBOL(seq_putc);
662
Joe Perches6798a8c2015-09-11 13:07:48 -0700663void seq_puts(struct seq_file *m, const char *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664{
665 int len = strlen(s);
Joe Perches6798a8c2015-09-11 13:07:48 -0700666
667 if (m->count + len >= m->size) {
668 seq_set_overflow(m);
669 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 }
Joe Perches6798a8c2015-09-11 13:07:48 -0700671 memcpy(m->buf + m->count, s, len);
672 m->count += len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673}
674EXPORT_SYMBOL(seq_puts);
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700675
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700676/*
677 * A helper routine for putting decimal numbers without rich format of printf().
678 * only 'unsigned long long' is supported.
679 * This routine will put one byte delimiter + number into seq_file.
680 * This routine is very quick when you show lots of numbers.
681 * In usual cases, it will be better to use seq_printf(). It's easier to read.
682 */
Joe Perches6798a8c2015-09-11 13:07:48 -0700683void seq_put_decimal_ull(struct seq_file *m, char delimiter,
684 unsigned long long num)
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700685{
686 int len;
687
688 if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */
689 goto overflow;
690
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700691 if (delimiter)
692 m->buf[m->count++] = delimiter;
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700693
694 if (num < 10) {
695 m->buf[m->count++] = num + '0';
Joe Perches6798a8c2015-09-11 13:07:48 -0700696 return;
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700697 }
698
699 len = num_to_str(m->buf + m->count, m->size - m->count, num);
700 if (!len)
701 goto overflow;
702 m->count += len;
Joe Perches6798a8c2015-09-11 13:07:48 -0700703 return;
704
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700705overflow:
KAMEZAWA Hiroyukie075f592012-03-23 15:02:55 -0700706 seq_set_overflow(m);
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700707}
708EXPORT_SYMBOL(seq_put_decimal_ull);
709
Joe Perches6798a8c2015-09-11 13:07:48 -0700710void seq_put_decimal_ll(struct seq_file *m, char delimiter, long long num)
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700711{
712 if (num < 0) {
713 if (m->count + 3 >= m->size) {
KAMEZAWA Hiroyukie075f592012-03-23 15:02:55 -0700714 seq_set_overflow(m);
Joe Perches6798a8c2015-09-11 13:07:48 -0700715 return;
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700716 }
717 if (delimiter)
718 m->buf[m->count++] = delimiter;
719 num = -num;
720 delimiter = '-';
721 }
Joe Perches6798a8c2015-09-11 13:07:48 -0700722 seq_put_decimal_ull(m, delimiter, num);
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700723}
724EXPORT_SYMBOL(seq_put_decimal_ll);
725
Peter Oberparleiter0b923602009-06-17 16:28:05 -0700726/**
727 * seq_write - write arbitrary data to buffer
728 * @seq: seq_file identifying the buffer to which data should be written
729 * @data: data address
730 * @len: number of bytes
731 *
732 * Return 0 on success, non-zero otherwise.
733 */
734int seq_write(struct seq_file *seq, const void *data, size_t len)
735{
736 if (seq->count + len < seq->size) {
737 memcpy(seq->buf + seq->count, data, len);
738 seq->count += len;
739 return 0;
740 }
KAMEZAWA Hiroyukie075f592012-03-23 15:02:55 -0700741 seq_set_overflow(seq);
Peter Oberparleiter0b923602009-06-17 16:28:05 -0700742 return -1;
743}
744EXPORT_SYMBOL(seq_write);
745
Tetsuo Handa839cc2a2013-11-14 14:31:56 -0800746/**
747 * seq_pad - write padding spaces to buffer
748 * @m: seq_file identifying the buffer to which data should be written
749 * @c: the byte to append after padding if non-zero
750 */
751void seq_pad(struct seq_file *m, char c)
752{
753 int size = m->pad_until - m->count;
754 if (size > 0)
755 seq_printf(m, "%*s", size, "");
756 if (c)
757 seq_putc(m, c);
758}
759EXPORT_SYMBOL(seq_pad);
760
Andy Shevchenko37607102015-09-09 15:38:33 -0700761/* A complete analogue of print_hex_dump() */
762void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
763 int rowsize, int groupsize, const void *buf, size_t len,
764 bool ascii)
765{
766 const u8 *ptr = buf;
767 int i, linelen, remaining = len;
Andy Shevchenko8b91a312015-11-06 16:32:37 -0800768 char *buffer;
769 size_t size;
Andy Shevchenko37607102015-09-09 15:38:33 -0700770 int ret;
771
772 if (rowsize != 16 && rowsize != 32)
773 rowsize = 16;
774
775 for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) {
776 linelen = min(remaining, rowsize);
777 remaining -= rowsize;
778
779 switch (prefix_type) {
780 case DUMP_PREFIX_ADDRESS:
781 seq_printf(m, "%s%p: ", prefix_str, ptr + i);
782 break;
783 case DUMP_PREFIX_OFFSET:
784 seq_printf(m, "%s%.8x: ", prefix_str, i);
785 break;
786 default:
787 seq_printf(m, "%s", prefix_str);
788 break;
789 }
790
Andy Shevchenko8b91a312015-11-06 16:32:37 -0800791 size = seq_get_buf(m, &buffer);
Andy Shevchenko37607102015-09-09 15:38:33 -0700792 ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
Andy Shevchenko8b91a312015-11-06 16:32:37 -0800793 buffer, size, ascii);
794 seq_commit(m, ret < size ? ret : -1);
795
796 seq_putc(m, '\n');
Andy Shevchenko37607102015-09-09 15:38:33 -0700797 }
798}
799EXPORT_SYMBOL(seq_hex_dump);
800
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700801struct list_head *seq_list_start(struct list_head *head, loff_t pos)
802{
803 struct list_head *lh;
804
805 list_for_each(lh, head)
806 if (pos-- == 0)
807 return lh;
808
809 return NULL;
810}
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700811EXPORT_SYMBOL(seq_list_start);
812
813struct list_head *seq_list_start_head(struct list_head *head, loff_t pos)
814{
815 if (!pos)
816 return head;
817
818 return seq_list_start(head, pos - 1);
819}
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700820EXPORT_SYMBOL(seq_list_start_head);
821
822struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos)
823{
824 struct list_head *lh;
825
826 lh = ((struct list_head *)v)->next;
827 ++*ppos;
828 return lh == head ? NULL : lh;
829}
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700830EXPORT_SYMBOL(seq_list_next);
Li Zefan66655de2010-02-08 23:18:22 +0000831
832/**
833 * seq_hlist_start - start an iteration of a hlist
834 * @head: the head of the hlist
835 * @pos: the start position of the sequence
836 *
837 * Called at seq_file->op->start().
838 */
839struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos)
840{
841 struct hlist_node *node;
842
843 hlist_for_each(node, head)
844 if (pos-- == 0)
845 return node;
846 return NULL;
847}
848EXPORT_SYMBOL(seq_hlist_start);
849
850/**
851 * seq_hlist_start_head - start an iteration of a hlist
852 * @head: the head of the hlist
853 * @pos: the start position of the sequence
854 *
855 * Called at seq_file->op->start(). Call this function if you want to
856 * print a header at the top of the output.
857 */
858struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos)
859{
860 if (!pos)
861 return SEQ_START_TOKEN;
862
863 return seq_hlist_start(head, pos - 1);
864}
865EXPORT_SYMBOL(seq_hlist_start_head);
866
867/**
868 * seq_hlist_next - move to the next position of the hlist
869 * @v: the current iterator
870 * @head: the head of the hlist
Randy Dunlap138860b2010-03-04 09:37:12 -0800871 * @ppos: the current position
Li Zefan66655de2010-02-08 23:18:22 +0000872 *
873 * Called at seq_file->op->next().
874 */
875struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
876 loff_t *ppos)
877{
878 struct hlist_node *node = v;
879
880 ++*ppos;
881 if (v == SEQ_START_TOKEN)
882 return head->first;
883 else
884 return node->next;
885}
886EXPORT_SYMBOL(seq_hlist_next);
stephen hemminger1cc52322010-02-22 07:57:17 +0000887
888/**
889 * seq_hlist_start_rcu - start an iteration of a hlist protected by RCU
890 * @head: the head of the hlist
891 * @pos: the start position of the sequence
892 *
893 * Called at seq_file->op->start().
894 *
895 * This list-traversal primitive may safely run concurrently with
896 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
897 * as long as the traversal is guarded by rcu_read_lock().
898 */
899struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
900 loff_t pos)
901{
902 struct hlist_node *node;
903
904 __hlist_for_each_rcu(node, head)
905 if (pos-- == 0)
906 return node;
907 return NULL;
908}
909EXPORT_SYMBOL(seq_hlist_start_rcu);
910
911/**
912 * seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU
913 * @head: the head of the hlist
914 * @pos: the start position of the sequence
915 *
916 * Called at seq_file->op->start(). Call this function if you want to
917 * print a header at the top of the output.
918 *
919 * This list-traversal primitive may safely run concurrently with
920 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
921 * as long as the traversal is guarded by rcu_read_lock().
922 */
923struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
924 loff_t pos)
925{
926 if (!pos)
927 return SEQ_START_TOKEN;
928
929 return seq_hlist_start_rcu(head, pos - 1);
930}
931EXPORT_SYMBOL(seq_hlist_start_head_rcu);
932
933/**
934 * seq_hlist_next_rcu - move to the next position of the hlist protected by RCU
935 * @v: the current iterator
936 * @head: the head of the hlist
Randy Dunlap138860b2010-03-04 09:37:12 -0800937 * @ppos: the current position
stephen hemminger1cc52322010-02-22 07:57:17 +0000938 *
939 * Called at seq_file->op->next().
940 *
941 * This list-traversal primitive may safely run concurrently with
942 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
943 * as long as the traversal is guarded by rcu_read_lock().
944 */
945struct hlist_node *seq_hlist_next_rcu(void *v,
946 struct hlist_head *head,
947 loff_t *ppos)
948{
949 struct hlist_node *node = v;
950
951 ++*ppos;
952 if (v == SEQ_START_TOKEN)
953 return rcu_dereference(head->first);
954 else
955 return rcu_dereference(node->next);
956}
957EXPORT_SYMBOL(seq_hlist_next_rcu);
Jeff Layton0bc77382013-06-21 08:58:21 -0400958
959/**
960 * seq_hlist_start_precpu - start an iteration of a percpu hlist array
961 * @head: pointer to percpu array of struct hlist_heads
962 * @cpu: pointer to cpu "cursor"
963 * @pos: start position of sequence
964 *
965 * Called at seq_file->op->start().
966 */
967struct hlist_node *
968seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos)
969{
970 struct hlist_node *node;
971
972 for_each_possible_cpu(*cpu) {
973 hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
974 if (pos-- == 0)
975 return node;
976 }
977 }
978 return NULL;
979}
980EXPORT_SYMBOL(seq_hlist_start_percpu);
981
982/**
983 * seq_hlist_next_percpu - move to the next position of the percpu hlist array
984 * @v: pointer to current hlist_node
985 * @head: pointer to percpu array of struct hlist_heads
986 * @cpu: pointer to cpu "cursor"
987 * @pos: start position of sequence
988 *
989 * Called at seq_file->op->next().
990 */
991struct hlist_node *
992seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
993 int *cpu, loff_t *pos)
994{
995 struct hlist_node *node = v;
996
997 ++*pos;
998
999 if (node->next)
1000 return node->next;
1001
1002 for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
1003 *cpu = cpumask_next(*cpu, cpu_possible_mask)) {
1004 struct hlist_head *bucket = per_cpu_ptr(head, *cpu);
1005
1006 if (!hlist_empty(bucket))
1007 return bucket->first;
1008 }
1009 return NULL;
1010}
1011EXPORT_SYMBOL(seq_hlist_next_percpu);