blob: 368bfb92b115c0e99ce4c654f6fdecb6ec5a2763 [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;
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;
Vegard Nossum088bf2f2016-08-25 15:17:11 -0700226 if (!m->count) {
227 m->from = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 m->index++;
Vegard Nossum088bf2f2016-08-25 15:17:11 -0700229 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 if (!size)
231 goto Done;
232 }
233 /* we need at least one record in buffer */
Al Viro4cdfe842008-08-24 07:45:33 -0400234 pos = m->index;
235 p = m->op->start(m, &pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 while (1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 err = PTR_ERR(p);
238 if (!p || IS_ERR(p))
239 break;
240 err = m->op->show(m, p);
Al Viro521b5d02008-03-28 00:46:41 -0400241 if (err < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 break;
Al Viro521b5d02008-03-28 00:46:41 -0400243 if (unlikely(err))
244 m->count = 0;
Al Viro4cdfe842008-08-24 07:45:33 -0400245 if (unlikely(!m->count)) {
246 p = m->op->next(m, p, &pos);
247 m->index = pos;
248 continue;
249 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 if (m->count < m->size)
251 goto Fill;
252 m->op->stop(m, p);
Heiko Carstens058504e2014-07-02 15:22:37 -0700253 kvfree(m->buf);
Al Viro801a7602013-11-19 01:20:43 +0000254 m->count = 0;
Heiko Carstens058504e2014-07-02 15:22:37 -0700255 m->buf = seq_buf_alloc(m->size <<= 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 if (!m->buf)
257 goto Enomem;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 m->version = 0;
Al Viro4cdfe842008-08-24 07:45:33 -0400259 pos = m->index;
260 p = m->op->start(m, &pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 }
262 m->op->stop(m, p);
263 m->count = 0;
264 goto Done;
265Fill:
266 /* they want more? let's try to get some more */
267 while (m->count < size) {
268 size_t offs = m->count;
269 loff_t next = pos;
270 p = m->op->next(m, p, &next);
271 if (!p || IS_ERR(p)) {
272 err = PTR_ERR(p);
273 break;
274 }
275 err = m->op->show(m, p);
Joe Perches1f33c412014-09-29 16:08:21 -0700276 if (seq_has_overflowed(m) || err) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 m->count = offs;
Al Viro521b5d02008-03-28 00:46:41 -0400278 if (likely(err <= 0))
279 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 }
281 pos = next;
282 }
283 m->op->stop(m, p);
284 n = min(m->count, size);
285 err = copy_to_user(buf, m->buf, n);
286 if (err)
287 goto Efault;
288 copied += n;
289 m->count -= n;
290 if (m->count)
291 m->from = n;
292 else
293 pos++;
294 m->index = pos;
295Done:
296 if (!copied)
297 copied = err;
Eric Biederman8f19d472009-02-18 14:48:16 -0800298 else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 *ppos += copied;
Eric Biederman8f19d472009-02-18 14:48:16 -0800300 m->read_pos += copied;
301 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 file->f_version = m->version;
Ingo Molnar0ac17592006-03-23 03:00:37 -0800303 mutex_unlock(&m->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 return copied;
305Enomem:
306 err = -ENOMEM;
307 goto Done;
308Efault:
309 err = -EFAULT;
310 goto Done;
311}
312EXPORT_SYMBOL(seq_read);
313
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314/**
315 * seq_lseek - ->llseek() method for sequential files.
Martin Waitz67be2dd2005-05-01 08:59:26 -0700316 * @file: the file in question
317 * @offset: new position
Randy Dunlap254adaa2013-01-09 17:13:00 -0800318 * @whence: 0 for absolute, 1 for relative position
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 *
320 * Ready-made ->f_op->llseek()
321 */
Andrew Morton965c8e52012-12-17 15:59:39 -0800322loff_t seq_lseek(struct file *file, loff_t offset, int whence)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323{
Joe Perches8209e2f2010-09-04 18:52:49 -0700324 struct seq_file *m = file->private_data;
David Sterba16abef02008-04-22 15:09:22 +0200325 loff_t retval = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326
Ingo Molnar0ac17592006-03-23 03:00:37 -0800327 mutex_lock(&m->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 m->version = file->f_version;
Andrew Morton965c8e52012-12-17 15:59:39 -0800329 switch (whence) {
Andrew Morton5e62ade2013-02-27 17:03:22 -0800330 case SEEK_CUR:
331 offset += file->f_pos;
332 case SEEK_SET:
333 if (offset < 0)
334 break;
335 retval = offset;
336 if (offset != m->read_pos) {
337 while ((retval = traverse(m, offset)) == -EAGAIN)
338 ;
339 if (retval) {
340 /* with extreme prejudice... */
341 file->f_pos = 0;
342 m->read_pos = 0;
343 m->version = 0;
344 m->index = 0;
345 m->count = 0;
346 } else {
347 m->read_pos = offset;
348 retval = file->f_pos = offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 }
Gu Zheng05e16742013-10-25 18:15:06 +0800350 } else {
351 file->f_pos = offset;
Andrew Morton5e62ade2013-02-27 17:03:22 -0800352 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 file->f_version = m->version;
Alexey Dobriyan00c57462007-07-15 23:40:22 -0700355 mutex_unlock(&m->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 return retval;
357}
358EXPORT_SYMBOL(seq_lseek);
359
360/**
361 * seq_release - free the structures associated with sequential file.
362 * @file: file in question
Al Viro6131ffa2013-02-27 16:59:05 -0500363 * @inode: its inode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 *
365 * Frees the structures associated with sequential file; can be used
366 * as ->f_op->release() if you don't have private data to destroy.
367 */
368int seq_release(struct inode *inode, struct file *file)
369{
Joe Perches8209e2f2010-09-04 18:52:49 -0700370 struct seq_file *m = file->private_data;
Heiko Carstens058504e2014-07-02 15:22:37 -0700371 kvfree(m->buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 kfree(m);
373 return 0;
374}
375EXPORT_SYMBOL(seq_release);
376
377/**
378 * seq_escape - print string into buffer, escaping some characters
379 * @m: target buffer
380 * @s: string
381 * @esc: set of characters that need escaping
382 *
383 * Puts string into buffer, replacing each occurrence of character from
Joe Perches6798a8c2015-09-11 13:07:48 -0700384 * @esc with usual octal escape.
385 * Use seq_has_overflowed() to check for errors.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 */
Joe Perches6798a8c2015-09-11 13:07:48 -0700387void seq_escape(struct seq_file *m, const char *s, const char *esc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388{
Andy Shevchenko25c6bb72015-11-06 16:32:40 -0800389 char *buf;
390 size_t size = seq_get_buf(m, &buf);
391 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392
Andy Shevchenko25c6bb72015-11-06 16:32:40 -0800393 ret = string_escape_str(s, buf, size, ESCAPE_OCTAL, esc);
394 seq_commit(m, ret < size ? ret : -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395}
396EXPORT_SYMBOL(seq_escape);
397
Joe Perches6798a8c2015-09-11 13:07:48 -0700398void seq_vprintf(struct seq_file *m, const char *f, va_list args)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 int len;
401
402 if (m->count < m->size) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 if (m->count + len < m->size) {
405 m->count += len;
Joe Perches6798a8c2015-09-11 13:07:48 -0700406 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407 }
408 }
KAMEZAWA Hiroyukie075f592012-03-23 15:02:55 -0700409 seq_set_overflow(m);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410}
Steven Whitehousea4808142012-06-11 13:16:35 +0100411EXPORT_SYMBOL(seq_vprintf);
412
Joe Perches6798a8c2015-09-11 13:07:48 -0700413void seq_printf(struct seq_file *m, const char *f, ...)
Steven Whitehousea4808142012-06-11 13:16:35 +0100414{
Steven Whitehousea4808142012-06-11 13:16:35 +0100415 va_list args;
416
417 va_start(args, f);
Joe Perches6798a8c2015-09-11 13:07:48 -0700418 seq_vprintf(m, f, args);
Steven Whitehousea4808142012-06-11 13:16:35 +0100419 va_end(args);
Steven Whitehousea4808142012-06-11 13:16:35 +0100420}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421EXPORT_SYMBOL(seq_printf);
422
Török Edwin74e2f332008-11-22 13:28:48 +0200423/**
Török Edwin958086d2008-11-23 23:24:53 +0200424 * mangle_path - mangle and copy path to buffer beginning
425 * @s: buffer start
426 * @p: beginning of path in above buffer
427 * @esc: set of characters that need escaping
Török Edwin74e2f332008-11-22 13:28:48 +0200428 *
429 * Copy the path from @p to @s, replacing each occurrence of character from
430 * @esc with usual octal escape.
431 * Returns pointer past last written character in @s, or NULL in case of
432 * failure.
433 */
Al Viro8c9379e2011-12-08 20:18:57 -0500434char *mangle_path(char *s, const char *p, const char *esc)
Ram Pai6092d042008-03-27 13:06:20 +0100435{
436 while (s <= p) {
437 char c = *p++;
438 if (!c) {
439 return s;
440 } else if (!strchr(esc, c)) {
441 *s++ = c;
442 } else if (s + 4 > p) {
443 break;
444 } else {
445 *s++ = '\\';
446 *s++ = '0' + ((c & 0300) >> 6);
447 *s++ = '0' + ((c & 070) >> 3);
448 *s++ = '0' + (c & 07);
449 }
450 }
451 return NULL;
452}
Ingo Molnar604094f2008-11-28 18:03:22 +0100453EXPORT_SYMBOL(mangle_path);
Ram Pai6092d042008-03-27 13:06:20 +0100454
Arjan van de Ven52afeef2008-12-01 14:35:00 -0800455/**
456 * seq_path - seq_file interface to print a pathname
457 * @m: the seq_file handle
458 * @path: the struct path to print
459 * @esc: set of characters to escape in the output
460 *
461 * return the absolute path of 'path', as represented by the
462 * dentry / mnt pair in the path parameter.
Ram Pai6092d042008-03-27 13:06:20 +0100463 */
Al Viro8c9379e2011-12-08 20:18:57 -0500464int seq_path(struct seq_file *m, const struct path *path, const char *esc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465{
Miklos Szeredif8439802009-09-21 14:48:36 +0200466 char *buf;
467 size_t size = seq_get_buf(m, &buf);
468 int res = -1;
469
470 if (size) {
471 char *p = d_path(path, buf, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 if (!IS_ERR(p)) {
Miklos Szeredif8439802009-09-21 14:48:36 +0200473 char *end = mangle_path(buf, p, esc);
474 if (end)
475 res = end - buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 }
477 }
Miklos Szeredif8439802009-09-21 14:48:36 +0200478 seq_commit(m, res);
479
480 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481}
482EXPORT_SYMBOL(seq_path);
483
Miklos Szeredi2726d562015-06-19 10:30:28 +0200484/**
485 * seq_file_path - seq_file interface to print a pathname of a file
486 * @m: the seq_file handle
487 * @file: the struct file to print
488 * @esc: set of characters to escape in the output
489 *
490 * return the absolute path to the file.
491 */
492int seq_file_path(struct seq_file *m, struct file *file, const char *esc)
493{
494 return seq_path(m, &file->f_path, esc);
495}
496EXPORT_SYMBOL(seq_file_path);
497
Ram Pai6092d042008-03-27 13:06:20 +0100498/*
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100499 * Same as seq_path, but relative to supplied root.
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100500 */
Al Viro8c9379e2011-12-08 20:18:57 -0500501int seq_path_root(struct seq_file *m, const struct path *path,
502 const struct path *root, const char *esc)
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100503{
Miklos Szeredif8439802009-09-21 14:48:36 +0200504 char *buf;
505 size_t size = seq_get_buf(m, &buf);
506 int res = -ENAMETOOLONG;
507
508 if (size) {
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100509 char *p;
510
Miklos Szeredif8439802009-09-21 14:48:36 +0200511 p = __d_path(path, root, buf, size);
Al Viro02125a82011-12-05 08:43:34 -0500512 if (!p)
513 return SEQ_SKIP;
Miklos Szeredif8439802009-09-21 14:48:36 +0200514 res = PTR_ERR(p);
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100515 if (!IS_ERR(p)) {
Miklos Szeredif8439802009-09-21 14:48:36 +0200516 char *end = mangle_path(buf, p, esc);
517 if (end)
518 res = end - buf;
519 else
520 res = -ENAMETOOLONG;
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100521 }
522 }
Miklos Szeredif8439802009-09-21 14:48:36 +0200523 seq_commit(m, res);
524
Al Viro02125a82011-12-05 08:43:34 -0500525 return res < 0 && res != -ENAMETOOLONG ? res : 0;
Miklos Szeredi9d1bc6012008-03-27 13:06:21 +0100526}
527
528/*
Ram Pai6092d042008-03-27 13:06:20 +0100529 * returns the path of the 'dentry' from the root of its filesystem.
530 */
Al Viro8c9379e2011-12-08 20:18:57 -0500531int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc)
Ram Pai6092d042008-03-27 13:06:20 +0100532{
Miklos Szeredif8439802009-09-21 14:48:36 +0200533 char *buf;
534 size_t size = seq_get_buf(m, &buf);
535 int res = -1;
536
537 if (size) {
538 char *p = dentry_path(dentry, buf, size);
Ram Pai6092d042008-03-27 13:06:20 +0100539 if (!IS_ERR(p)) {
Miklos Szeredif8439802009-09-21 14:48:36 +0200540 char *end = mangle_path(buf, p, esc);
541 if (end)
542 res = end - buf;
Ram Pai6092d042008-03-27 13:06:20 +0100543 }
544 }
Miklos Szeredif8439802009-09-21 14:48:36 +0200545 seq_commit(m, res);
546
547 return res;
Ram Pai6092d042008-03-27 13:06:20 +0100548}
Omar Sandovalc8d3fe02015-05-18 02:16:31 -0700549EXPORT_SYMBOL(seq_dentry);
Ram Pai6092d042008-03-27 13:06:20 +0100550
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551static void *single_start(struct seq_file *p, loff_t *pos)
552{
553 return NULL + (*pos == 0);
554}
555
556static void *single_next(struct seq_file *p, void *v, loff_t *pos)
557{
558 ++*pos;
559 return NULL;
560}
561
562static void single_stop(struct seq_file *p, void *v)
563{
564}
565
566int single_open(struct file *file, int (*show)(struct seq_file *, void *),
567 void *data)
568{
569 struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL);
570 int res = -ENOMEM;
571
572 if (op) {
573 op->start = single_start;
574 op->next = single_next;
575 op->stop = single_stop;
576 op->show = show;
577 res = seq_open(file, op);
578 if (!res)
579 ((struct seq_file *)file->private_data)->private = data;
580 else
581 kfree(op);
582 }
583 return res;
584}
585EXPORT_SYMBOL(single_open);
586
Al Viro2043f492013-03-31 13:43:23 -0400587int single_open_size(struct file *file, int (*show)(struct seq_file *, void *),
588 void *data, size_t size)
589{
Heiko Carstens058504e2014-07-02 15:22:37 -0700590 char *buf = seq_buf_alloc(size);
Al Viro2043f492013-03-31 13:43:23 -0400591 int ret;
592 if (!buf)
593 return -ENOMEM;
594 ret = single_open(file, show, data);
595 if (ret) {
Heiko Carstens058504e2014-07-02 15:22:37 -0700596 kvfree(buf);
Al Viro2043f492013-03-31 13:43:23 -0400597 return ret;
598 }
599 ((struct seq_file *)file->private_data)->buf = buf;
600 ((struct seq_file *)file->private_data)->size = size;
601 return 0;
602}
603EXPORT_SYMBOL(single_open_size);
604
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605int single_release(struct inode *inode, struct file *file)
606{
Helge Deller15ad7cd2006-12-06 20:40:36 -0800607 const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 int res = seq_release(inode, file);
609 kfree(op);
610 return res;
611}
612EXPORT_SYMBOL(single_release);
613
614int seq_release_private(struct inode *inode, struct file *file)
615{
616 struct seq_file *seq = file->private_data;
617
618 kfree(seq->private);
619 seq->private = NULL;
620 return seq_release(inode, file);
621}
622EXPORT_SYMBOL(seq_release_private);
623
Pavel Emelyanov39699032007-10-10 02:28:42 -0700624void *__seq_open_private(struct file *f, const struct seq_operations *ops,
625 int psize)
626{
627 int rc;
628 void *private;
629 struct seq_file *seq;
630
631 private = kzalloc(psize, GFP_KERNEL);
632 if (private == NULL)
633 goto out;
634
635 rc = seq_open(f, ops);
636 if (rc < 0)
637 goto out_free;
638
639 seq = f->private_data;
640 seq->private = private;
641 return private;
642
643out_free:
644 kfree(private);
645out:
646 return NULL;
647}
648EXPORT_SYMBOL(__seq_open_private);
649
650int seq_open_private(struct file *filp, const struct seq_operations *ops,
651 int psize)
652{
653 return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;
654}
655EXPORT_SYMBOL(seq_open_private);
656
Joe Perches6798a8c2015-09-11 13:07:48 -0700657void seq_putc(struct seq_file *m, char c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658{
Joe Perches6798a8c2015-09-11 13:07:48 -0700659 if (m->count >= m->size)
660 return;
661
662 m->buf[m->count++] = c;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663}
664EXPORT_SYMBOL(seq_putc);
665
Joe Perches6798a8c2015-09-11 13:07:48 -0700666void seq_puts(struct seq_file *m, const char *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667{
668 int len = strlen(s);
Joe Perches6798a8c2015-09-11 13:07:48 -0700669
670 if (m->count + len >= m->size) {
671 seq_set_overflow(m);
672 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 }
Joe Perches6798a8c2015-09-11 13:07:48 -0700674 memcpy(m->buf + m->count, s, len);
675 m->count += len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676}
677EXPORT_SYMBOL(seq_puts);
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700678
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700679/*
680 * A helper routine for putting decimal numbers without rich format of printf().
681 * only 'unsigned long long' is supported.
Joe Perches75ba1d02016-10-07 17:02:20 -0700682 * This routine will put strlen(delimiter) + number into seq_file.
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700683 * This routine is very quick when you show lots of numbers.
684 * In usual cases, it will be better to use seq_printf(). It's easier to read.
685 */
Joe Perches75ba1d02016-10-07 17:02:20 -0700686void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
Joe Perches6798a8c2015-09-11 13:07:48 -0700687 unsigned long long num)
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700688{
689 int len;
690
691 if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */
692 goto overflow;
693
Joe Perches75ba1d02016-10-07 17:02:20 -0700694 len = strlen(delimiter);
695 if (m->count + len >= m->size)
696 goto overflow;
697
698 memcpy(m->buf + m->count, delimiter, len);
699 m->count += len;
700
701 if (m->count + 1 >= m->size)
702 goto overflow;
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700703
704 if (num < 10) {
705 m->buf[m->count++] = num + '0';
Joe Perches6798a8c2015-09-11 13:07:48 -0700706 return;
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700707 }
708
709 len = num_to_str(m->buf + m->count, m->size - m->count, num);
710 if (!len)
711 goto overflow;
Joe Perches75ba1d02016-10-07 17:02:20 -0700712
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700713 m->count += len;
Joe Perches6798a8c2015-09-11 13:07:48 -0700714 return;
715
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700716overflow:
KAMEZAWA Hiroyukie075f592012-03-23 15:02:55 -0700717 seq_set_overflow(m);
KAMEZAWA Hiroyuki1ac101a2012-03-23 15:02:54 -0700718}
719EXPORT_SYMBOL(seq_put_decimal_ull);
720
Joe Perches75ba1d02016-10-07 17:02:20 -0700721void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num)
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700722{
Joe Perches75ba1d02016-10-07 17:02:20 -0700723 int len;
724
725 if (m->count + 3 >= m->size) /* we'll write 2 bytes at least */
726 goto overflow;
727
728 len = strlen(delimiter);
729 if (m->count + len >= m->size)
730 goto overflow;
731
732 memcpy(m->buf + m->count, delimiter, len);
733 m->count += len;
734
735 if (m->count + 2 >= m->size)
736 goto overflow;
737
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700738 if (num < 0) {
Joe Perches75ba1d02016-10-07 17:02:20 -0700739 m->buf[m->count++] = '-';
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700740 num = -num;
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700741 }
Joe Perches75ba1d02016-10-07 17:02:20 -0700742
743 if (num < 10) {
744 m->buf[m->count++] = num + '0';
745 return;
746 }
747
748 len = num_to_str(m->buf + m->count, m->size - m->count, num);
749 if (!len)
750 goto overflow;
751
752 m->count += len;
753 return;
754
755overflow:
756 seq_set_overflow(m);
KAMEZAWA Hiroyukibda7bad2012-03-23 15:02:54 -0700757}
758EXPORT_SYMBOL(seq_put_decimal_ll);
759
Peter Oberparleiter0b923602009-06-17 16:28:05 -0700760/**
761 * seq_write - write arbitrary data to buffer
762 * @seq: seq_file identifying the buffer to which data should be written
763 * @data: data address
764 * @len: number of bytes
765 *
766 * Return 0 on success, non-zero otherwise.
767 */
768int seq_write(struct seq_file *seq, const void *data, size_t len)
769{
770 if (seq->count + len < seq->size) {
771 memcpy(seq->buf + seq->count, data, len);
772 seq->count += len;
773 return 0;
774 }
KAMEZAWA Hiroyukie075f592012-03-23 15:02:55 -0700775 seq_set_overflow(seq);
Peter Oberparleiter0b923602009-06-17 16:28:05 -0700776 return -1;
777}
778EXPORT_SYMBOL(seq_write);
779
Tetsuo Handa839cc2a2013-11-14 14:31:56 -0800780/**
781 * seq_pad - write padding spaces to buffer
782 * @m: seq_file identifying the buffer to which data should be written
783 * @c: the byte to append after padding if non-zero
784 */
785void seq_pad(struct seq_file *m, char c)
786{
787 int size = m->pad_until - m->count;
788 if (size > 0)
789 seq_printf(m, "%*s", size, "");
790 if (c)
791 seq_putc(m, c);
792}
793EXPORT_SYMBOL(seq_pad);
794
Andy Shevchenko37607102015-09-09 15:38:33 -0700795/* A complete analogue of print_hex_dump() */
796void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
797 int rowsize, int groupsize, const void *buf, size_t len,
798 bool ascii)
799{
800 const u8 *ptr = buf;
801 int i, linelen, remaining = len;
Andy Shevchenko8b91a312015-11-06 16:32:37 -0800802 char *buffer;
803 size_t size;
Andy Shevchenko37607102015-09-09 15:38:33 -0700804 int ret;
805
806 if (rowsize != 16 && rowsize != 32)
807 rowsize = 16;
808
809 for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) {
810 linelen = min(remaining, rowsize);
811 remaining -= rowsize;
812
813 switch (prefix_type) {
814 case DUMP_PREFIX_ADDRESS:
815 seq_printf(m, "%s%p: ", prefix_str, ptr + i);
816 break;
817 case DUMP_PREFIX_OFFSET:
818 seq_printf(m, "%s%.8x: ", prefix_str, i);
819 break;
820 default:
821 seq_printf(m, "%s", prefix_str);
822 break;
823 }
824
Andy Shevchenko8b91a312015-11-06 16:32:37 -0800825 size = seq_get_buf(m, &buffer);
Andy Shevchenko37607102015-09-09 15:38:33 -0700826 ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
Andy Shevchenko8b91a312015-11-06 16:32:37 -0800827 buffer, size, ascii);
828 seq_commit(m, ret < size ? ret : -1);
829
830 seq_putc(m, '\n');
Andy Shevchenko37607102015-09-09 15:38:33 -0700831 }
832}
833EXPORT_SYMBOL(seq_hex_dump);
834
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700835struct list_head *seq_list_start(struct list_head *head, loff_t pos)
836{
837 struct list_head *lh;
838
839 list_for_each(lh, head)
840 if (pos-- == 0)
841 return lh;
842
843 return NULL;
844}
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700845EXPORT_SYMBOL(seq_list_start);
846
847struct list_head *seq_list_start_head(struct list_head *head, loff_t pos)
848{
849 if (!pos)
850 return head;
851
852 return seq_list_start(head, pos - 1);
853}
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700854EXPORT_SYMBOL(seq_list_start_head);
855
856struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos)
857{
858 struct list_head *lh;
859
860 lh = ((struct list_head *)v)->next;
861 ++*ppos;
862 return lh == head ? NULL : lh;
863}
Pavel Emelianovbcf67e12007-07-10 17:22:26 -0700864EXPORT_SYMBOL(seq_list_next);
Li Zefan66655de2010-02-08 23:18:22 +0000865
866/**
867 * seq_hlist_start - start an iteration of a hlist
868 * @head: the head of the hlist
869 * @pos: the start position of the sequence
870 *
871 * Called at seq_file->op->start().
872 */
873struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos)
874{
875 struct hlist_node *node;
876
877 hlist_for_each(node, head)
878 if (pos-- == 0)
879 return node;
880 return NULL;
881}
882EXPORT_SYMBOL(seq_hlist_start);
883
884/**
885 * seq_hlist_start_head - start an iteration of a hlist
886 * @head: the head of the hlist
887 * @pos: the start position of the sequence
888 *
889 * Called at seq_file->op->start(). Call this function if you want to
890 * print a header at the top of the output.
891 */
892struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos)
893{
894 if (!pos)
895 return SEQ_START_TOKEN;
896
897 return seq_hlist_start(head, pos - 1);
898}
899EXPORT_SYMBOL(seq_hlist_start_head);
900
901/**
902 * seq_hlist_next - move to the next position of the hlist
903 * @v: the current iterator
904 * @head: the head of the hlist
Randy Dunlap138860b2010-03-04 09:37:12 -0800905 * @ppos: the current position
Li Zefan66655de2010-02-08 23:18:22 +0000906 *
907 * Called at seq_file->op->next().
908 */
909struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
910 loff_t *ppos)
911{
912 struct hlist_node *node = v;
913
914 ++*ppos;
915 if (v == SEQ_START_TOKEN)
916 return head->first;
917 else
918 return node->next;
919}
920EXPORT_SYMBOL(seq_hlist_next);
stephen hemminger1cc52322010-02-22 07:57:17 +0000921
922/**
923 * seq_hlist_start_rcu - start an iteration of a hlist protected by RCU
924 * @head: the head of the hlist
925 * @pos: the start position of the sequence
926 *
927 * Called at seq_file->op->start().
928 *
929 * This list-traversal primitive may safely run concurrently with
930 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
931 * as long as the traversal is guarded by rcu_read_lock().
932 */
933struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
934 loff_t pos)
935{
936 struct hlist_node *node;
937
938 __hlist_for_each_rcu(node, head)
939 if (pos-- == 0)
940 return node;
941 return NULL;
942}
943EXPORT_SYMBOL(seq_hlist_start_rcu);
944
945/**
946 * seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU
947 * @head: the head of the hlist
948 * @pos: the start position of the sequence
949 *
950 * Called at seq_file->op->start(). Call this function if you want to
951 * print a header at the top of the output.
952 *
953 * This list-traversal primitive may safely run concurrently with
954 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
955 * as long as the traversal is guarded by rcu_read_lock().
956 */
957struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
958 loff_t pos)
959{
960 if (!pos)
961 return SEQ_START_TOKEN;
962
963 return seq_hlist_start_rcu(head, pos - 1);
964}
965EXPORT_SYMBOL(seq_hlist_start_head_rcu);
966
967/**
968 * seq_hlist_next_rcu - move to the next position of the hlist protected by RCU
969 * @v: the current iterator
970 * @head: the head of the hlist
Randy Dunlap138860b2010-03-04 09:37:12 -0800971 * @ppos: the current position
stephen hemminger1cc52322010-02-22 07:57:17 +0000972 *
973 * Called at seq_file->op->next().
974 *
975 * This list-traversal primitive may safely run concurrently with
976 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
977 * as long as the traversal is guarded by rcu_read_lock().
978 */
979struct hlist_node *seq_hlist_next_rcu(void *v,
980 struct hlist_head *head,
981 loff_t *ppos)
982{
983 struct hlist_node *node = v;
984
985 ++*ppos;
986 if (v == SEQ_START_TOKEN)
987 return rcu_dereference(head->first);
988 else
989 return rcu_dereference(node->next);
990}
991EXPORT_SYMBOL(seq_hlist_next_rcu);
Jeff Layton0bc77382013-06-21 08:58:21 -0400992
993/**
994 * seq_hlist_start_precpu - start an iteration of a percpu hlist array
995 * @head: pointer to percpu array of struct hlist_heads
996 * @cpu: pointer to cpu "cursor"
997 * @pos: start position of sequence
998 *
999 * Called at seq_file->op->start().
1000 */
1001struct hlist_node *
1002seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos)
1003{
1004 struct hlist_node *node;
1005
1006 for_each_possible_cpu(*cpu) {
1007 hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
1008 if (pos-- == 0)
1009 return node;
1010 }
1011 }
1012 return NULL;
1013}
1014EXPORT_SYMBOL(seq_hlist_start_percpu);
1015
1016/**
1017 * seq_hlist_next_percpu - move to the next position of the percpu hlist array
1018 * @v: pointer to current hlist_node
1019 * @head: pointer to percpu array of struct hlist_heads
1020 * @cpu: pointer to cpu "cursor"
1021 * @pos: start position of sequence
1022 *
1023 * Called at seq_file->op->next().
1024 */
1025struct hlist_node *
1026seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
1027 int *cpu, loff_t *pos)
1028{
1029 struct hlist_node *node = v;
1030
1031 ++*pos;
1032
1033 if (node->next)
1034 return node->next;
1035
1036 for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
1037 *cpu = cpumask_next(*cpu, cpu_possible_mask)) {
1038 struct hlist_head *bucket = per_cpu_ptr(head, *cpu);
1039
1040 if (!hlist_empty(bucket))
1041 return bucket->first;
1042 }
1043 return NULL;
1044}
1045EXPORT_SYMBOL(seq_hlist_next_percpu);