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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/seq_file.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/seq_file.c')
-rw-r--r--fs/seq_file.c440
1 files changed, 440 insertions, 0 deletions
diff --git a/fs/seq_file.c b/fs/seq_file.c
new file mode 100644
index 000000000000..650c43ba86c4
--- /dev/null
+++ b/fs/seq_file.c
@@ -0,0 +1,440 @@
1/*
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>
9#include <linux/module.h>
10#include <linux/seq_file.h>
11#include <linux/slab.h>
12
13#include <asm/uaccess.h>
14#include <asm/page.h>
15
16/**
17 * seq_open - initialize sequential file
18 * @file: file we initialize
19 * @op: method table describing the sequence
20 *
21 * seq_open() sets @file, associating it with a sequence described
22 * by @op. @op->start() sets the iterator up and returns the first
23 * element of sequence. @op->stop() shuts it down. @op->next()
24 * returns the next element of sequence. @op->show() prints element
25 * into the buffer. In case of error ->start() and ->next() return
26 * ERR_PTR(error). In the end of sequence they return %NULL. ->show()
27 * returns 0 in case of success and negative number in case of error.
28 */
29int seq_open(struct file *file, struct seq_operations *op)
30{
31 struct seq_file *p = kmalloc(sizeof(*p), GFP_KERNEL);
32 if (!p)
33 return -ENOMEM;
34 memset(p, 0, sizeof(*p));
35 sema_init(&p->sem, 1);
36 p->op = op;
37 file->private_data = p;
38
39 /*
40 * Wrappers around seq_open(e.g. swaps_open) need to be
41 * aware of this. If they set f_version themselves, they
42 * should call seq_open first and then set f_version.
43 */
44 file->f_version = 0;
45
46 /* SEQ files support lseek, but not pread/pwrite */
47 file->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
48 return 0;
49}
50EXPORT_SYMBOL(seq_open);
51
52/**
53 * seq_read - ->read() method for sequential files.
54 * @file, @buf, @size, @ppos: see file_operations method
55 *
56 * Ready-made ->f_op->read()
57 */
58ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
59{
60 struct seq_file *m = (struct seq_file *)file->private_data;
61 size_t copied = 0;
62 loff_t pos;
63 size_t n;
64 void *p;
65 int err = 0;
66
67 down(&m->sem);
68 /*
69 * seq_file->op->..m_start/m_stop/m_next may do special actions
70 * or optimisations based on the file->f_version, so we want to
71 * pass the file->f_version to those methods.
72 *
73 * seq_file->version is just copy of f_version, and seq_file
74 * methods can treat it simply as file version.
75 * It is copied in first and copied out after all operations.
76 * It is convenient to have it as part of structure to avoid the
77 * need of passing another argument to all the seq_file methods.
78 */
79 m->version = file->f_version;
80 /* grab buffer if we didn't have one */
81 if (!m->buf) {
82 m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
83 if (!m->buf)
84 goto Enomem;
85 }
86 /* if not empty - flush it first */
87 if (m->count) {
88 n = min(m->count, size);
89 err = copy_to_user(buf, m->buf + m->from, n);
90 if (err)
91 goto Efault;
92 m->count -= n;
93 m->from += n;
94 size -= n;
95 buf += n;
96 copied += n;
97 if (!m->count)
98 m->index++;
99 if (!size)
100 goto Done;
101 }
102 /* we need at least one record in buffer */
103 while (1) {
104 pos = m->index;
105 p = m->op->start(m, &pos);
106 err = PTR_ERR(p);
107 if (!p || IS_ERR(p))
108 break;
109 err = m->op->show(m, p);
110 if (err)
111 break;
112 if (m->count < m->size)
113 goto Fill;
114 m->op->stop(m, p);
115 kfree(m->buf);
116 m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
117 if (!m->buf)
118 goto Enomem;
119 m->count = 0;
120 m->version = 0;
121 }
122 m->op->stop(m, p);
123 m->count = 0;
124 goto Done;
125Fill:
126 /* they want more? let's try to get some more */
127 while (m->count < size) {
128 size_t offs = m->count;
129 loff_t next = pos;
130 p = m->op->next(m, p, &next);
131 if (!p || IS_ERR(p)) {
132 err = PTR_ERR(p);
133 break;
134 }
135 err = m->op->show(m, p);
136 if (err || m->count == m->size) {
137 m->count = offs;
138 break;
139 }
140 pos = next;
141 }
142 m->op->stop(m, p);
143 n = min(m->count, size);
144 err = copy_to_user(buf, m->buf, n);
145 if (err)
146 goto Efault;
147 copied += n;
148 m->count -= n;
149 if (m->count)
150 m->from = n;
151 else
152 pos++;
153 m->index = pos;
154Done:
155 if (!copied)
156 copied = err;
157 else
158 *ppos += copied;
159 file->f_version = m->version;
160 up(&m->sem);
161 return copied;
162Enomem:
163 err = -ENOMEM;
164 goto Done;
165Efault:
166 err = -EFAULT;
167 goto Done;
168}
169EXPORT_SYMBOL(seq_read);
170
171static int traverse(struct seq_file *m, loff_t offset)
172{
173 loff_t pos = 0;
174 int error = 0;
175 void *p;
176
177 m->version = 0;
178 m->index = 0;
179 m->count = m->from = 0;
180 if (!offset)
181 return 0;
182 if (!m->buf) {
183 m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
184 if (!m->buf)
185 return -ENOMEM;
186 }
187 p = m->op->start(m, &m->index);
188 while (p) {
189 error = PTR_ERR(p);
190 if (IS_ERR(p))
191 break;
192 error = m->op->show(m, p);
193 if (error)
194 break;
195 if (m->count == m->size)
196 goto Eoverflow;
197 if (pos + m->count > offset) {
198 m->from = offset - pos;
199 m->count -= m->from;
200 break;
201 }
202 pos += m->count;
203 m->count = 0;
204 if (pos == offset) {
205 m->index++;
206 break;
207 }
208 p = m->op->next(m, p, &m->index);
209 }
210 m->op->stop(m, p);
211 return error;
212
213Eoverflow:
214 m->op->stop(m, p);
215 kfree(m->buf);
216 m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
217 return !m->buf ? -ENOMEM : -EAGAIN;
218}
219
220/**
221 * seq_lseek - ->llseek() method for sequential files.
222 * @file, @offset, @origin: see file_operations method
223 *
224 * Ready-made ->f_op->llseek()
225 */
226loff_t seq_lseek(struct file *file, loff_t offset, int origin)
227{
228 struct seq_file *m = (struct seq_file *)file->private_data;
229 long long retval = -EINVAL;
230
231 down(&m->sem);
232 m->version = file->f_version;
233 switch (origin) {
234 case 1:
235 offset += file->f_pos;
236 case 0:
237 if (offset < 0)
238 break;
239 retval = offset;
240 if (offset != file->f_pos) {
241 while ((retval=traverse(m, offset)) == -EAGAIN)
242 ;
243 if (retval) {
244 /* with extreme prejudice... */
245 file->f_pos = 0;
246 m->version = 0;
247 m->index = 0;
248 m->count = 0;
249 } else {
250 retval = file->f_pos = offset;
251 }
252 }
253 }
254 up(&m->sem);
255 file->f_version = m->version;
256 return retval;
257}
258EXPORT_SYMBOL(seq_lseek);
259
260/**
261 * seq_release - free the structures associated with sequential file.
262 * @file: file in question
263 * @inode: file->f_dentry->d_inode
264 *
265 * Frees the structures associated with sequential file; can be used
266 * as ->f_op->release() if you don't have private data to destroy.
267 */
268int seq_release(struct inode *inode, struct file *file)
269{
270 struct seq_file *m = (struct seq_file *)file->private_data;
271 kfree(m->buf);
272 kfree(m);
273 return 0;
274}
275EXPORT_SYMBOL(seq_release);
276
277/**
278 * seq_escape - print string into buffer, escaping some characters
279 * @m: target buffer
280 * @s: string
281 * @esc: set of characters that need escaping
282 *
283 * Puts string into buffer, replacing each occurrence of character from
284 * @esc with usual octal escape. Returns 0 in case of success, -1 - in
285 * case of overflow.
286 */
287int seq_escape(struct seq_file *m, const char *s, const char *esc)
288{
289 char *end = m->buf + m->size;
290 char *p;
291 char c;
292
293 for (p = m->buf + m->count; (c = *s) != '\0' && p < end; s++) {
294 if (!strchr(esc, c)) {
295 *p++ = c;
296 continue;
297 }
298 if (p + 3 < end) {
299 *p++ = '\\';
300 *p++ = '0' + ((c & 0300) >> 6);
301 *p++ = '0' + ((c & 070) >> 3);
302 *p++ = '0' + (c & 07);
303 continue;
304 }
305 m->count = m->size;
306 return -1;
307 }
308 m->count = p - m->buf;
309 return 0;
310}
311EXPORT_SYMBOL(seq_escape);
312
313int seq_printf(struct seq_file *m, const char *f, ...)
314{
315 va_list args;
316 int len;
317
318 if (m->count < m->size) {
319 va_start(args, f);
320 len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
321 va_end(args);
322 if (m->count + len < m->size) {
323 m->count += len;
324 return 0;
325 }
326 }
327 m->count = m->size;
328 return -1;
329}
330EXPORT_SYMBOL(seq_printf);
331
332int seq_path(struct seq_file *m,
333 struct vfsmount *mnt, struct dentry *dentry,
334 char *esc)
335{
336 if (m->count < m->size) {
337 char *s = m->buf + m->count;
338 char *p = d_path(dentry, mnt, s, m->size - m->count);
339 if (!IS_ERR(p)) {
340 while (s <= p) {
341 char c = *p++;
342 if (!c) {
343 p = m->buf + m->count;
344 m->count = s - m->buf;
345 return s - p;
346 } else if (!strchr(esc, c)) {
347 *s++ = c;
348 } else if (s + 4 > p) {
349 break;
350 } else {
351 *s++ = '\\';
352 *s++ = '0' + ((c & 0300) >> 6);
353 *s++ = '0' + ((c & 070) >> 3);
354 *s++ = '0' + (c & 07);
355 }
356 }
357 }
358 }
359 m->count = m->size;
360 return -1;
361}
362EXPORT_SYMBOL(seq_path);
363
364static void *single_start(struct seq_file *p, loff_t *pos)
365{
366 return NULL + (*pos == 0);
367}
368
369static void *single_next(struct seq_file *p, void *v, loff_t *pos)
370{
371 ++*pos;
372 return NULL;
373}
374
375static void single_stop(struct seq_file *p, void *v)
376{
377}
378
379int single_open(struct file *file, int (*show)(struct seq_file *, void *),
380 void *data)
381{
382 struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL);
383 int res = -ENOMEM;
384
385 if (op) {
386 op->start = single_start;
387 op->next = single_next;
388 op->stop = single_stop;
389 op->show = show;
390 res = seq_open(file, op);
391 if (!res)
392 ((struct seq_file *)file->private_data)->private = data;
393 else
394 kfree(op);
395 }
396 return res;
397}
398EXPORT_SYMBOL(single_open);
399
400int single_release(struct inode *inode, struct file *file)
401{
402 struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
403 int res = seq_release(inode, file);
404 kfree(op);
405 return res;
406}
407EXPORT_SYMBOL(single_release);
408
409int seq_release_private(struct inode *inode, struct file *file)
410{
411 struct seq_file *seq = file->private_data;
412
413 kfree(seq->private);
414 seq->private = NULL;
415 return seq_release(inode, file);
416}
417EXPORT_SYMBOL(seq_release_private);
418
419int seq_putc(struct seq_file *m, char c)
420{
421 if (m->count < m->size) {
422 m->buf[m->count++] = c;
423 return 0;
424 }
425 return -1;
426}
427EXPORT_SYMBOL(seq_putc);
428
429int seq_puts(struct seq_file *m, const char *s)
430{
431 int len = strlen(s);
432 if (m->count + len < m->size) {
433 memcpy(m->buf + m->count, s, len);
434 m->count += len;
435 return 0;
436 }
437 m->count = m->size;
438 return -1;
439}
440EXPORT_SYMBOL(seq_puts);