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Commit | Line | Data |
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1 | /* | |
2 | * lib/dynamic_debug.c | |
3 | * | |
4 | * make pr_debug()/dev_dbg() calls runtime configurable based upon their | |
5 | * source module. | |
6 | * | |
7 | * Copyright (C) 2008 Jason Baron <jbaron@redhat.com> | |
8 | * By Greg Banks <gnb@melbourne.sgi.com> | |
9 | * Copyright (c) 2008 Silicon Graphics Inc. All Rights Reserved. | |
10 | */ | |
11 | ||
12 | #include <linux/kernel.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/moduleparam.h> | |
15 | #include <linux/kallsyms.h> | |
16 | #include <linux/version.h> | |
17 | #include <linux/types.h> | |
18 | #include <linux/mutex.h> | |
19 | #include <linux/proc_fs.h> | |
20 | #include <linux/seq_file.h> | |
21 | #include <linux/list.h> | |
22 | #include <linux/sysctl.h> | |
23 | #include <linux/ctype.h> | |
24 | #include <linux/uaccess.h> | |
25 | #include <linux/dynamic_debug.h> | |
26 | #include <linux/debugfs.h> | |
27 | ||
28 | extern struct _ddebug __start___verbose[]; | |
29 | extern struct _ddebug __stop___verbose[]; | |
30 | ||
31 | /* dynamic_debug_enabled, and dynamic_debug_enabled2 are bitmasks in which | |
32 | * bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They | |
33 | * use independent hash functions, to reduce the chance of false positives. | |
34 | */ | |
35 | long long dynamic_debug_enabled; | |
36 | EXPORT_SYMBOL_GPL(dynamic_debug_enabled); | |
37 | long long dynamic_debug_enabled2; | |
38 | EXPORT_SYMBOL_GPL(dynamic_debug_enabled2); | |
39 | ||
40 | struct ddebug_table { | |
41 | struct list_head link; | |
42 | char *mod_name; | |
43 | unsigned int num_ddebugs; | |
44 | unsigned int num_enabled; | |
45 | struct _ddebug *ddebugs; | |
46 | }; | |
47 | ||
48 | struct ddebug_query { | |
49 | const char *filename; | |
50 | const char *module; | |
51 | const char *function; | |
52 | const char *format; | |
53 | unsigned int first_lineno, last_lineno; | |
54 | }; | |
55 | ||
56 | struct ddebug_iter { | |
57 | struct ddebug_table *table; | |
58 | unsigned int idx; | |
59 | }; | |
60 | ||
61 | static DEFINE_MUTEX(ddebug_lock); | |
62 | static LIST_HEAD(ddebug_tables); | |
63 | static int verbose = 0; | |
64 | ||
65 | /* Return the last part of a pathname */ | |
66 | static inline const char *basename(const char *path) | |
67 | { | |
68 | const char *tail = strrchr(path, '/'); | |
69 | return tail ? tail+1 : path; | |
70 | } | |
71 | ||
72 | /* format a string into buf[] which describes the _ddebug's flags */ | |
73 | static char *ddebug_describe_flags(struct _ddebug *dp, char *buf, | |
74 | size_t maxlen) | |
75 | { | |
76 | char *p = buf; | |
77 | ||
78 | BUG_ON(maxlen < 4); | |
79 | if (dp->flags & _DPRINTK_FLAGS_PRINT) | |
80 | *p++ = 'p'; | |
81 | if (p == buf) | |
82 | *p++ = '-'; | |
83 | *p = '\0'; | |
84 | ||
85 | return buf; | |
86 | } | |
87 | ||
88 | /* | |
89 | * must be called with ddebug_lock held | |
90 | */ | |
91 | ||
92 | static int disabled_hash(char hash, bool first_table) | |
93 | { | |
94 | struct ddebug_table *dt; | |
95 | char table_hash_value; | |
96 | ||
97 | list_for_each_entry(dt, &ddebug_tables, link) { | |
98 | if (first_table) | |
99 | table_hash_value = dt->ddebugs->primary_hash; | |
100 | else | |
101 | table_hash_value = dt->ddebugs->secondary_hash; | |
102 | if (dt->num_enabled && (hash == table_hash_value)) | |
103 | return 0; | |
104 | } | |
105 | return 1; | |
106 | } | |
107 | ||
108 | /* | |
109 | * Search the tables for _ddebug's which match the given | |
110 | * `query' and apply the `flags' and `mask' to them. Tells | |
111 | * the user which ddebug's were changed, or whether none | |
112 | * were matched. | |
113 | */ | |
114 | static void ddebug_change(const struct ddebug_query *query, | |
115 | unsigned int flags, unsigned int mask) | |
116 | { | |
117 | int i; | |
118 | struct ddebug_table *dt; | |
119 | unsigned int newflags; | |
120 | unsigned int nfound = 0; | |
121 | char flagbuf[8]; | |
122 | ||
123 | /* search for matching ddebugs */ | |
124 | mutex_lock(&ddebug_lock); | |
125 | list_for_each_entry(dt, &ddebug_tables, link) { | |
126 | ||
127 | /* match against the module name */ | |
128 | if (query->module != NULL && | |
129 | strcmp(query->module, dt->mod_name)) | |
130 | continue; | |
131 | ||
132 | for (i = 0 ; i < dt->num_ddebugs ; i++) { | |
133 | struct _ddebug *dp = &dt->ddebugs[i]; | |
134 | ||
135 | /* match against the source filename */ | |
136 | if (query->filename != NULL && | |
137 | strcmp(query->filename, dp->filename) && | |
138 | strcmp(query->filename, basename(dp->filename))) | |
139 | continue; | |
140 | ||
141 | /* match against the function */ | |
142 | if (query->function != NULL && | |
143 | strcmp(query->function, dp->function)) | |
144 | continue; | |
145 | ||
146 | /* match against the format */ | |
147 | if (query->format != NULL && | |
148 | strstr(dp->format, query->format) == NULL) | |
149 | continue; | |
150 | ||
151 | /* match against the line number range */ | |
152 | if (query->first_lineno && | |
153 | dp->lineno < query->first_lineno) | |
154 | continue; | |
155 | if (query->last_lineno && | |
156 | dp->lineno > query->last_lineno) | |
157 | continue; | |
158 | ||
159 | nfound++; | |
160 | ||
161 | newflags = (dp->flags & mask) | flags; | |
162 | if (newflags == dp->flags) | |
163 | continue; | |
164 | ||
165 | if (!newflags) | |
166 | dt->num_enabled--; | |
167 | else if (!dp-flags) | |
168 | dt->num_enabled++; | |
169 | dp->flags = newflags; | |
170 | if (newflags) { | |
171 | dynamic_debug_enabled |= | |
172 | (1LL << dp->primary_hash); | |
173 | dynamic_debug_enabled2 |= | |
174 | (1LL << dp->secondary_hash); | |
175 | } else { | |
176 | if (disabled_hash(dp->primary_hash, true)) | |
177 | dynamic_debug_enabled &= | |
178 | ~(1LL << dp->primary_hash); | |
179 | if (disabled_hash(dp->secondary_hash, false)) | |
180 | dynamic_debug_enabled2 &= | |
181 | ~(1LL << dp->secondary_hash); | |
182 | } | |
183 | if (verbose) | |
184 | printk(KERN_INFO | |
185 | "ddebug: changed %s:%d [%s]%s %s\n", | |
186 | dp->filename, dp->lineno, | |
187 | dt->mod_name, dp->function, | |
188 | ddebug_describe_flags(dp, flagbuf, | |
189 | sizeof(flagbuf))); | |
190 | } | |
191 | } | |
192 | mutex_unlock(&ddebug_lock); | |
193 | ||
194 | if (!nfound && verbose) | |
195 | printk(KERN_INFO "ddebug: no matches for query\n"); | |
196 | } | |
197 | ||
198 | /* | |
199 | * Wrapper around strsep() to collapse the multiple empty tokens | |
200 | * that it returns when fed sequences of separator characters. | |
201 | * Now, if we had strtok_r()... | |
202 | */ | |
203 | static inline char *nearly_strtok_r(char **p, const char *sep) | |
204 | { | |
205 | char *r; | |
206 | ||
207 | while ((r = strsep(p, sep)) != NULL && *r == '\0') | |
208 | ; | |
209 | return r; | |
210 | } | |
211 | ||
212 | /* | |
213 | * Split the buffer `buf' into space-separated words. | |
214 | * Return the number of such words or <0 on error. | |
215 | */ | |
216 | static int ddebug_tokenize(char *buf, char *words[], int maxwords) | |
217 | { | |
218 | int nwords = 0; | |
219 | ||
220 | while (nwords < maxwords && | |
221 | (words[nwords] = nearly_strtok_r(&buf, " \t\r\n")) != NULL) | |
222 | nwords++; | |
223 | if (buf) | |
224 | return -EINVAL; /* ran out of words[] before bytes */ | |
225 | ||
226 | if (verbose) { | |
227 | int i; | |
228 | printk(KERN_INFO "%s: split into words:", __func__); | |
229 | for (i = 0 ; i < nwords ; i++) | |
230 | printk(" \"%s\"", words[i]); | |
231 | printk("\n"); | |
232 | } | |
233 | ||
234 | return nwords; | |
235 | } | |
236 | ||
237 | /* | |
238 | * Parse a single line number. Note that the empty string "" | |
239 | * is treated as a special case and converted to zero, which | |
240 | * is later treated as a "don't care" value. | |
241 | */ | |
242 | static inline int parse_lineno(const char *str, unsigned int *val) | |
243 | { | |
244 | char *end = NULL; | |
245 | BUG_ON(str == NULL); | |
246 | if (*str == '\0') { | |
247 | *val = 0; | |
248 | return 0; | |
249 | } | |
250 | *val = simple_strtoul(str, &end, 10); | |
251 | return end == NULL || end == str || *end != '\0' ? -EINVAL : 0; | |
252 | } | |
253 | ||
254 | /* | |
255 | * Undo octal escaping in a string, inplace. This is useful to | |
256 | * allow the user to express a query which matches a format | |
257 | * containing embedded spaces. | |
258 | */ | |
259 | #define isodigit(c) ((c) >= '0' && (c) <= '7') | |
260 | static char *unescape(char *str) | |
261 | { | |
262 | char *in = str; | |
263 | char *out = str; | |
264 | ||
265 | while (*in) { | |
266 | if (*in == '\\') { | |
267 | if (in[1] == '\\') { | |
268 | *out++ = '\\'; | |
269 | in += 2; | |
270 | continue; | |
271 | } else if (in[1] == 't') { | |
272 | *out++ = '\t'; | |
273 | in += 2; | |
274 | continue; | |
275 | } else if (in[1] == 'n') { | |
276 | *out++ = '\n'; | |
277 | in += 2; | |
278 | continue; | |
279 | } else if (isodigit(in[1]) && | |
280 | isodigit(in[2]) && | |
281 | isodigit(in[3])) { | |
282 | *out++ = ((in[1] - '0')<<6) | | |
283 | ((in[2] - '0')<<3) | | |
284 | (in[3] - '0'); | |
285 | in += 4; | |
286 | continue; | |
287 | } | |
288 | } | |
289 | *out++ = *in++; | |
290 | } | |
291 | *out = '\0'; | |
292 | ||
293 | return str; | |
294 | } | |
295 | ||
296 | /* | |
297 | * Parse words[] as a ddebug query specification, which is a series | |
298 | * of (keyword, value) pairs chosen from these possibilities: | |
299 | * | |
300 | * func <function-name> | |
301 | * file <full-pathname> | |
302 | * file <base-filename> | |
303 | * module <module-name> | |
304 | * format <escaped-string-to-find-in-format> | |
305 | * line <lineno> | |
306 | * line <first-lineno>-<last-lineno> // where either may be empty | |
307 | */ | |
308 | static int ddebug_parse_query(char *words[], int nwords, | |
309 | struct ddebug_query *query) | |
310 | { | |
311 | unsigned int i; | |
312 | ||
313 | /* check we have an even number of words */ | |
314 | if (nwords % 2 != 0) | |
315 | return -EINVAL; | |
316 | memset(query, 0, sizeof(*query)); | |
317 | ||
318 | for (i = 0 ; i < nwords ; i += 2) { | |
319 | if (!strcmp(words[i], "func")) | |
320 | query->function = words[i+1]; | |
321 | else if (!strcmp(words[i], "file")) | |
322 | query->filename = words[i+1]; | |
323 | else if (!strcmp(words[i], "module")) | |
324 | query->module = words[i+1]; | |
325 | else if (!strcmp(words[i], "format")) | |
326 | query->format = unescape(words[i+1]); | |
327 | else if (!strcmp(words[i], "line")) { | |
328 | char *first = words[i+1]; | |
329 | char *last = strchr(first, '-'); | |
330 | if (last) | |
331 | *last++ = '\0'; | |
332 | if (parse_lineno(first, &query->first_lineno) < 0) | |
333 | return -EINVAL; | |
334 | if (last != NULL) { | |
335 | /* range <first>-<last> */ | |
336 | if (parse_lineno(last, &query->last_lineno) < 0) | |
337 | return -EINVAL; | |
338 | } else { | |
339 | query->last_lineno = query->first_lineno; | |
340 | } | |
341 | } else { | |
342 | if (verbose) | |
343 | printk(KERN_ERR "%s: unknown keyword \"%s\"\n", | |
344 | __func__, words[i]); | |
345 | return -EINVAL; | |
346 | } | |
347 | } | |
348 | ||
349 | if (verbose) | |
350 | printk(KERN_INFO "%s: q->function=\"%s\" q->filename=\"%s\" " | |
351 | "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n", | |
352 | __func__, query->function, query->filename, | |
353 | query->module, query->format, query->first_lineno, | |
354 | query->last_lineno); | |
355 | ||
356 | return 0; | |
357 | } | |
358 | ||
359 | /* | |
360 | * Parse `str' as a flags specification, format [-+=][p]+. | |
361 | * Sets up *maskp and *flagsp to be used when changing the | |
362 | * flags fields of matched _ddebug's. Returns 0 on success | |
363 | * or <0 on error. | |
364 | */ | |
365 | static int ddebug_parse_flags(const char *str, unsigned int *flagsp, | |
366 | unsigned int *maskp) | |
367 | { | |
368 | unsigned flags = 0; | |
369 | int op = '='; | |
370 | ||
371 | switch (*str) { | |
372 | case '+': | |
373 | case '-': | |
374 | case '=': | |
375 | op = *str++; | |
376 | break; | |
377 | default: | |
378 | return -EINVAL; | |
379 | } | |
380 | if (verbose) | |
381 | printk(KERN_INFO "%s: op='%c'\n", __func__, op); | |
382 | ||
383 | for ( ; *str ; ++str) { | |
384 | switch (*str) { | |
385 | case 'p': | |
386 | flags |= _DPRINTK_FLAGS_PRINT; | |
387 | break; | |
388 | default: | |
389 | return -EINVAL; | |
390 | } | |
391 | } | |
392 | if (flags == 0) | |
393 | return -EINVAL; | |
394 | if (verbose) | |
395 | printk(KERN_INFO "%s: flags=0x%x\n", __func__, flags); | |
396 | ||
397 | /* calculate final *flagsp, *maskp according to mask and op */ | |
398 | switch (op) { | |
399 | case '=': | |
400 | *maskp = 0; | |
401 | *flagsp = flags; | |
402 | break; | |
403 | case '+': | |
404 | *maskp = ~0U; | |
405 | *flagsp = flags; | |
406 | break; | |
407 | case '-': | |
408 | *maskp = ~flags; | |
409 | *flagsp = 0; | |
410 | break; | |
411 | } | |
412 | if (verbose) | |
413 | printk(KERN_INFO "%s: *flagsp=0x%x *maskp=0x%x\n", | |
414 | __func__, *flagsp, *maskp); | |
415 | return 0; | |
416 | } | |
417 | ||
418 | /* | |
419 | * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the | |
420 | * command text from userspace, parses and executes it. | |
421 | */ | |
422 | static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf, | |
423 | size_t len, loff_t *offp) | |
424 | { | |
425 | unsigned int flags = 0, mask = 0; | |
426 | struct ddebug_query query; | |
427 | #define MAXWORDS 9 | |
428 | int nwords; | |
429 | char *words[MAXWORDS]; | |
430 | char tmpbuf[256]; | |
431 | ||
432 | if (len == 0) | |
433 | return 0; | |
434 | /* we don't check *offp -- multiple writes() are allowed */ | |
435 | if (len > sizeof(tmpbuf)-1) | |
436 | return -E2BIG; | |
437 | if (copy_from_user(tmpbuf, ubuf, len)) | |
438 | return -EFAULT; | |
439 | tmpbuf[len] = '\0'; | |
440 | if (verbose) | |
441 | printk(KERN_INFO "%s: read %d bytes from userspace\n", | |
442 | __func__, (int)len); | |
443 | ||
444 | nwords = ddebug_tokenize(tmpbuf, words, MAXWORDS); | |
445 | if (nwords < 0) | |
446 | return -EINVAL; | |
447 | if (ddebug_parse_query(words, nwords-1, &query)) | |
448 | return -EINVAL; | |
449 | if (ddebug_parse_flags(words[nwords-1], &flags, &mask)) | |
450 | return -EINVAL; | |
451 | ||
452 | /* actually go and implement the change */ | |
453 | ddebug_change(&query, flags, mask); | |
454 | ||
455 | *offp += len; | |
456 | return len; | |
457 | } | |
458 | ||
459 | /* | |
460 | * Set the iterator to point to the first _ddebug object | |
461 | * and return a pointer to that first object. Returns | |
462 | * NULL if there are no _ddebugs at all. | |
463 | */ | |
464 | static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter) | |
465 | { | |
466 | if (list_empty(&ddebug_tables)) { | |
467 | iter->table = NULL; | |
468 | iter->idx = 0; | |
469 | return NULL; | |
470 | } | |
471 | iter->table = list_entry(ddebug_tables.next, | |
472 | struct ddebug_table, link); | |
473 | iter->idx = 0; | |
474 | return &iter->table->ddebugs[iter->idx]; | |
475 | } | |
476 | ||
477 | /* | |
478 | * Advance the iterator to point to the next _ddebug | |
479 | * object from the one the iterator currently points at, | |
480 | * and returns a pointer to the new _ddebug. Returns | |
481 | * NULL if the iterator has seen all the _ddebugs. | |
482 | */ | |
483 | static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter) | |
484 | { | |
485 | if (iter->table == NULL) | |
486 | return NULL; | |
487 | if (++iter->idx == iter->table->num_ddebugs) { | |
488 | /* iterate to next table */ | |
489 | iter->idx = 0; | |
490 | if (list_is_last(&iter->table->link, &ddebug_tables)) { | |
491 | iter->table = NULL; | |
492 | return NULL; | |
493 | } | |
494 | iter->table = list_entry(iter->table->link.next, | |
495 | struct ddebug_table, link); | |
496 | } | |
497 | return &iter->table->ddebugs[iter->idx]; | |
498 | } | |
499 | ||
500 | /* | |
501 | * Seq_ops start method. Called at the start of every | |
502 | * read() call from userspace. Takes the ddebug_lock and | |
503 | * seeks the seq_file's iterator to the given position. | |
504 | */ | |
505 | static void *ddebug_proc_start(struct seq_file *m, loff_t *pos) | |
506 | { | |
507 | struct ddebug_iter *iter = m->private; | |
508 | struct _ddebug *dp; | |
509 | int n = *pos; | |
510 | ||
511 | if (verbose) | |
512 | printk(KERN_INFO "%s: called m=%p *pos=%lld\n", | |
513 | __func__, m, (unsigned long long)*pos); | |
514 | ||
515 | mutex_lock(&ddebug_lock); | |
516 | ||
517 | if (!n) | |
518 | return SEQ_START_TOKEN; | |
519 | if (n < 0) | |
520 | return NULL; | |
521 | dp = ddebug_iter_first(iter); | |
522 | while (dp != NULL && --n > 0) | |
523 | dp = ddebug_iter_next(iter); | |
524 | return dp; | |
525 | } | |
526 | ||
527 | /* | |
528 | * Seq_ops next method. Called several times within a read() | |
529 | * call from userspace, with ddebug_lock held. Walks to the | |
530 | * next _ddebug object with a special case for the header line. | |
531 | */ | |
532 | static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos) | |
533 | { | |
534 | struct ddebug_iter *iter = m->private; | |
535 | struct _ddebug *dp; | |
536 | ||
537 | if (verbose) | |
538 | printk(KERN_INFO "%s: called m=%p p=%p *pos=%lld\n", | |
539 | __func__, m, p, (unsigned long long)*pos); | |
540 | ||
541 | if (p == SEQ_START_TOKEN) | |
542 | dp = ddebug_iter_first(iter); | |
543 | else | |
544 | dp = ddebug_iter_next(iter); | |
545 | ++*pos; | |
546 | return dp; | |
547 | } | |
548 | ||
549 | /* | |
550 | * Seq_ops show method. Called several times within a read() | |
551 | * call from userspace, with ddebug_lock held. Formats the | |
552 | * current _ddebug as a single human-readable line, with a | |
553 | * special case for the header line. | |
554 | */ | |
555 | static int ddebug_proc_show(struct seq_file *m, void *p) | |
556 | { | |
557 | struct ddebug_iter *iter = m->private; | |
558 | struct _ddebug *dp = p; | |
559 | char flagsbuf[8]; | |
560 | ||
561 | if (verbose) | |
562 | printk(KERN_INFO "%s: called m=%p p=%p\n", | |
563 | __func__, m, p); | |
564 | ||
565 | if (p == SEQ_START_TOKEN) { | |
566 | seq_puts(m, | |
567 | "# filename:lineno [module]function flags format\n"); | |
568 | return 0; | |
569 | } | |
570 | ||
571 | seq_printf(m, "%s:%u [%s]%s %s \"", | |
572 | dp->filename, dp->lineno, | |
573 | iter->table->mod_name, dp->function, | |
574 | ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf))); | |
575 | seq_escape(m, dp->format, "\t\r\n\""); | |
576 | seq_puts(m, "\"\n"); | |
577 | ||
578 | return 0; | |
579 | } | |
580 | ||
581 | /* | |
582 | * Seq_ops stop method. Called at the end of each read() | |
583 | * call from userspace. Drops ddebug_lock. | |
584 | */ | |
585 | static void ddebug_proc_stop(struct seq_file *m, void *p) | |
586 | { | |
587 | if (verbose) | |
588 | printk(KERN_INFO "%s: called m=%p p=%p\n", | |
589 | __func__, m, p); | |
590 | mutex_unlock(&ddebug_lock); | |
591 | } | |
592 | ||
593 | static const struct seq_operations ddebug_proc_seqops = { | |
594 | .start = ddebug_proc_start, | |
595 | .next = ddebug_proc_next, | |
596 | .show = ddebug_proc_show, | |
597 | .stop = ddebug_proc_stop | |
598 | }; | |
599 | ||
600 | /* | |
601 | * File_ops->open method for <debugfs>/dynamic_debug/control. Does the seq_file | |
602 | * setup dance, and also creates an iterator to walk the _ddebugs. | |
603 | * Note that we create a seq_file always, even for O_WRONLY files | |
604 | * where it's not needed, as doing so simplifies the ->release method. | |
605 | */ | |
606 | static int ddebug_proc_open(struct inode *inode, struct file *file) | |
607 | { | |
608 | struct ddebug_iter *iter; | |
609 | int err; | |
610 | ||
611 | if (verbose) | |
612 | printk(KERN_INFO "%s: called\n", __func__); | |
613 | ||
614 | iter = kzalloc(sizeof(*iter), GFP_KERNEL); | |
615 | if (iter == NULL) | |
616 | return -ENOMEM; | |
617 | ||
618 | err = seq_open(file, &ddebug_proc_seqops); | |
619 | if (err) { | |
620 | kfree(iter); | |
621 | return err; | |
622 | } | |
623 | ((struct seq_file *) file->private_data)->private = iter; | |
624 | return 0; | |
625 | } | |
626 | ||
627 | static const struct file_operations ddebug_proc_fops = { | |
628 | .owner = THIS_MODULE, | |
629 | .open = ddebug_proc_open, | |
630 | .read = seq_read, | |
631 | .llseek = seq_lseek, | |
632 | .release = seq_release_private, | |
633 | .write = ddebug_proc_write | |
634 | }; | |
635 | ||
636 | /* | |
637 | * Allocate a new ddebug_table for the given module | |
638 | * and add it to the global list. | |
639 | */ | |
640 | int ddebug_add_module(struct _ddebug *tab, unsigned int n, | |
641 | const char *name) | |
642 | { | |
643 | struct ddebug_table *dt; | |
644 | char *new_name; | |
645 | ||
646 | dt = kzalloc(sizeof(*dt), GFP_KERNEL); | |
647 | if (dt == NULL) | |
648 | return -ENOMEM; | |
649 | new_name = kstrdup(name, GFP_KERNEL); | |
650 | if (new_name == NULL) { | |
651 | kfree(dt); | |
652 | return -ENOMEM; | |
653 | } | |
654 | dt->mod_name = new_name; | |
655 | dt->num_ddebugs = n; | |
656 | dt->num_enabled = 0; | |
657 | dt->ddebugs = tab; | |
658 | ||
659 | mutex_lock(&ddebug_lock); | |
660 | list_add_tail(&dt->link, &ddebug_tables); | |
661 | mutex_unlock(&ddebug_lock); | |
662 | ||
663 | if (verbose) | |
664 | printk(KERN_INFO "%u debug prints in module %s\n", | |
665 | n, dt->mod_name); | |
666 | return 0; | |
667 | } | |
668 | EXPORT_SYMBOL_GPL(ddebug_add_module); | |
669 | ||
670 | static void ddebug_table_free(struct ddebug_table *dt) | |
671 | { | |
672 | list_del_init(&dt->link); | |
673 | kfree(dt->mod_name); | |
674 | kfree(dt); | |
675 | } | |
676 | ||
677 | /* | |
678 | * Called in response to a module being unloaded. Removes | |
679 | * any ddebug_table's which point at the module. | |
680 | */ | |
681 | int ddebug_remove_module(char *mod_name) | |
682 | { | |
683 | struct ddebug_table *dt, *nextdt; | |
684 | int ret = -ENOENT; | |
685 | ||
686 | if (verbose) | |
687 | printk(KERN_INFO "%s: removing module \"%s\"\n", | |
688 | __func__, mod_name); | |
689 | ||
690 | mutex_lock(&ddebug_lock); | |
691 | list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) { | |
692 | if (!strcmp(dt->mod_name, mod_name)) { | |
693 | ddebug_table_free(dt); | |
694 | ret = 0; | |
695 | } | |
696 | } | |
697 | mutex_unlock(&ddebug_lock); | |
698 | return ret; | |
699 | } | |
700 | EXPORT_SYMBOL_GPL(ddebug_remove_module); | |
701 | ||
702 | static void ddebug_remove_all_tables(void) | |
703 | { | |
704 | mutex_lock(&ddebug_lock); | |
705 | while (!list_empty(&ddebug_tables)) { | |
706 | struct ddebug_table *dt = list_entry(ddebug_tables.next, | |
707 | struct ddebug_table, | |
708 | link); | |
709 | ddebug_table_free(dt); | |
710 | } | |
711 | mutex_unlock(&ddebug_lock); | |
712 | } | |
713 | ||
714 | static int __init dynamic_debug_init(void) | |
715 | { | |
716 | struct dentry *dir, *file; | |
717 | struct _ddebug *iter, *iter_start; | |
718 | const char *modname = NULL; | |
719 | int ret = 0; | |
720 | int n = 0; | |
721 | ||
722 | dir = debugfs_create_dir("dynamic_debug", NULL); | |
723 | if (!dir) | |
724 | return -ENOMEM; | |
725 | file = debugfs_create_file("control", 0644, dir, NULL, | |
726 | &ddebug_proc_fops); | |
727 | if (!file) { | |
728 | debugfs_remove(dir); | |
729 | return -ENOMEM; | |
730 | } | |
731 | if (__start___verbose != __stop___verbose) { | |
732 | iter = __start___verbose; | |
733 | modname = iter->modname; | |
734 | iter_start = iter; | |
735 | for (; iter < __stop___verbose; iter++) { | |
736 | if (strcmp(modname, iter->modname)) { | |
737 | ret = ddebug_add_module(iter_start, n, modname); | |
738 | if (ret) | |
739 | goto out_free; | |
740 | n = 0; | |
741 | modname = iter->modname; | |
742 | iter_start = iter; | |
743 | } | |
744 | n++; | |
745 | } | |
746 | ret = ddebug_add_module(iter_start, n, modname); | |
747 | } | |
748 | out_free: | |
749 | if (ret) { | |
750 | ddebug_remove_all_tables(); | |
751 | debugfs_remove(dir); | |
752 | debugfs_remove(file); | |
753 | } | |
754 | return 0; | |
755 | } | |
756 | module_init(dynamic_debug_init); |