4 * make pr_debug()/dev_dbg() calls runtime configurable based upon their
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.
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/string.h>
25 #include <linux/uaccess.h>
26 #include <linux/dynamic_debug.h>
27 #include <linux/debugfs.h>
28 #include <linux/slab.h>
29 #include <linux/jump_label.h>
31 extern struct _ddebug __start___verbose
[];
32 extern struct _ddebug __stop___verbose
[];
35 struct list_head link
;
37 unsigned int num_ddebugs
;
38 unsigned int num_enabled
;
39 struct _ddebug
*ddebugs
;
47 unsigned int first_lineno
, last_lineno
;
51 struct ddebug_table
*table
;
55 static DEFINE_MUTEX(ddebug_lock
);
56 static LIST_HEAD(ddebug_tables
);
57 static int verbose
= 0;
59 /* Return the last part of a pathname */
60 static inline const char *basename(const char *path
)
62 const char *tail
= strrchr(path
, '/');
63 return tail
? tail
+1 : path
;
66 /* format a string into buf[] which describes the _ddebug's flags */
67 static char *ddebug_describe_flags(struct _ddebug
*dp
, char *buf
,
73 if (dp
->flags
& _DPRINTK_FLAGS_PRINT
)
83 * Search the tables for _ddebug's which match the given
84 * `query' and apply the `flags' and `mask' to them. Tells
85 * the user which ddebug's were changed, or whether none
88 static void ddebug_change(const struct ddebug_query
*query
,
89 unsigned int flags
, unsigned int mask
)
92 struct ddebug_table
*dt
;
93 unsigned int newflags
;
94 unsigned int nfound
= 0;
97 /* search for matching ddebugs */
98 mutex_lock(&ddebug_lock
);
99 list_for_each_entry(dt
, &ddebug_tables
, link
) {
101 /* match against the module name */
102 if (query
->module
!= NULL
&&
103 strcmp(query
->module
, dt
->mod_name
))
106 for (i
= 0 ; i
< dt
->num_ddebugs
; i
++) {
107 struct _ddebug
*dp
= &dt
->ddebugs
[i
];
109 /* match against the source filename */
110 if (query
->filename
!= NULL
&&
111 strcmp(query
->filename
, dp
->filename
) &&
112 strcmp(query
->filename
, basename(dp
->filename
)))
115 /* match against the function */
116 if (query
->function
!= NULL
&&
117 strcmp(query
->function
, dp
->function
))
120 /* match against the format */
121 if (query
->format
!= NULL
&&
122 strstr(dp
->format
, query
->format
) == NULL
)
125 /* match against the line number range */
126 if (query
->first_lineno
&&
127 dp
->lineno
< query
->first_lineno
)
129 if (query
->last_lineno
&&
130 dp
->lineno
> query
->last_lineno
)
135 newflags
= (dp
->flags
& mask
) | flags
;
136 if (newflags
== dp
->flags
)
143 dp
->flags
= newflags
;
145 jump_label_enable(&dp
->enabled
);
147 jump_label_disable(&dp
->enabled
);
151 "ddebug: changed %s:%d [%s]%s %s\n",
152 dp
->filename
, dp
->lineno
,
153 dt
->mod_name
, dp
->function
,
154 ddebug_describe_flags(dp
, flagbuf
,
158 mutex_unlock(&ddebug_lock
);
160 if (!nfound
&& verbose
)
161 printk(KERN_INFO
"ddebug: no matches for query\n");
165 * Split the buffer `buf' into space-separated words.
166 * Handles simple " and ' quoting, i.e. without nested,
167 * embedded or escaped \". Return the number of words
170 static int ddebug_tokenize(char *buf
, char *words
[], int maxwords
)
177 /* Skip leading whitespace */
178 buf
= skip_spaces(buf
);
180 break; /* oh, it was trailing whitespace */
182 /* Run `end' over a word, either whitespace separated or quoted */
183 if (*buf
== '"' || *buf
== '\'') {
185 for (end
= buf
; *end
&& *end
!= quote
; end
++)
188 return -EINVAL
; /* unclosed quote */
190 for (end
= buf
; *end
&& !isspace(*end
) ; end
++)
194 /* Here `buf' is the start of the word, `end' is one past the end */
196 if (nwords
== maxwords
)
197 return -EINVAL
; /* ran out of words[] before bytes */
199 *end
++ = '\0'; /* terminate the word */
200 words
[nwords
++] = buf
;
206 printk(KERN_INFO
"%s: split into words:", __func__
);
207 for (i
= 0 ; i
< nwords
; i
++)
208 printk(" \"%s\"", words
[i
]);
216 * Parse a single line number. Note that the empty string ""
217 * is treated as a special case and converted to zero, which
218 * is later treated as a "don't care" value.
220 static inline int parse_lineno(const char *str
, unsigned int *val
)
228 *val
= simple_strtoul(str
, &end
, 10);
229 return end
== NULL
|| end
== str
|| *end
!= '\0' ? -EINVAL
: 0;
233 * Undo octal escaping in a string, inplace. This is useful to
234 * allow the user to express a query which matches a format
235 * containing embedded spaces.
237 #define isodigit(c) ((c) >= '0' && (c) <= '7')
238 static char *unescape(char *str
)
249 } else if (in
[1] == 't') {
253 } else if (in
[1] == 'n') {
257 } else if (isodigit(in
[1]) &&
260 *out
++ = ((in
[1] - '0')<<6) |
275 * Parse words[] as a ddebug query specification, which is a series
276 * of (keyword, value) pairs chosen from these possibilities:
278 * func <function-name>
279 * file <full-pathname>
280 * file <base-filename>
281 * module <module-name>
282 * format <escaped-string-to-find-in-format>
284 * line <first-lineno>-<last-lineno> // where either may be empty
286 static int ddebug_parse_query(char *words
[], int nwords
,
287 struct ddebug_query
*query
)
291 /* check we have an even number of words */
294 memset(query
, 0, sizeof(*query
));
296 for (i
= 0 ; i
< nwords
; i
+= 2) {
297 if (!strcmp(words
[i
], "func"))
298 query
->function
= words
[i
+1];
299 else if (!strcmp(words
[i
], "file"))
300 query
->filename
= words
[i
+1];
301 else if (!strcmp(words
[i
], "module"))
302 query
->module
= words
[i
+1];
303 else if (!strcmp(words
[i
], "format"))
304 query
->format
= unescape(words
[i
+1]);
305 else if (!strcmp(words
[i
], "line")) {
306 char *first
= words
[i
+1];
307 char *last
= strchr(first
, '-');
310 if (parse_lineno(first
, &query
->first_lineno
) < 0)
313 /* range <first>-<last> */
314 if (parse_lineno(last
, &query
->last_lineno
) < 0)
317 query
->last_lineno
= query
->first_lineno
;
321 printk(KERN_ERR
"%s: unknown keyword \"%s\"\n",
328 printk(KERN_INFO
"%s: q->function=\"%s\" q->filename=\"%s\" "
329 "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
330 __func__
, query
->function
, query
->filename
,
331 query
->module
, query
->format
, query
->first_lineno
,
338 * Parse `str' as a flags specification, format [-+=][p]+.
339 * Sets up *maskp and *flagsp to be used when changing the
340 * flags fields of matched _ddebug's. Returns 0 on success
343 static int ddebug_parse_flags(const char *str
, unsigned int *flagsp
,
359 printk(KERN_INFO
"%s: op='%c'\n", __func__
, op
);
361 for ( ; *str
; ++str
) {
364 flags
|= _DPRINTK_FLAGS_PRINT
;
373 printk(KERN_INFO
"%s: flags=0x%x\n", __func__
, flags
);
375 /* calculate final *flagsp, *maskp according to mask and op */
391 printk(KERN_INFO
"%s: *flagsp=0x%x *maskp=0x%x\n",
392 __func__
, *flagsp
, *maskp
);
397 * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
398 * command text from userspace, parses and executes it.
400 static ssize_t
ddebug_proc_write(struct file
*file
, const char __user
*ubuf
,
401 size_t len
, loff_t
*offp
)
403 unsigned int flags
= 0, mask
= 0;
404 struct ddebug_query query
;
407 char *words
[MAXWORDS
];
412 /* we don't check *offp -- multiple writes() are allowed */
413 if (len
> sizeof(tmpbuf
)-1)
415 if (copy_from_user(tmpbuf
, ubuf
, len
))
419 printk(KERN_INFO
"%s: read %d bytes from userspace\n",
422 nwords
= ddebug_tokenize(tmpbuf
, words
, MAXWORDS
);
425 if (ddebug_parse_query(words
, nwords
-1, &query
))
427 if (ddebug_parse_flags(words
[nwords
-1], &flags
, &mask
))
430 /* actually go and implement the change */
431 ddebug_change(&query
, flags
, mask
);
438 * Set the iterator to point to the first _ddebug object
439 * and return a pointer to that first object. Returns
440 * NULL if there are no _ddebugs at all.
442 static struct _ddebug
*ddebug_iter_first(struct ddebug_iter
*iter
)
444 if (list_empty(&ddebug_tables
)) {
449 iter
->table
= list_entry(ddebug_tables
.next
,
450 struct ddebug_table
, link
);
452 return &iter
->table
->ddebugs
[iter
->idx
];
456 * Advance the iterator to point to the next _ddebug
457 * object from the one the iterator currently points at,
458 * and returns a pointer to the new _ddebug. Returns
459 * NULL if the iterator has seen all the _ddebugs.
461 static struct _ddebug
*ddebug_iter_next(struct ddebug_iter
*iter
)
463 if (iter
->table
== NULL
)
465 if (++iter
->idx
== iter
->table
->num_ddebugs
) {
466 /* iterate to next table */
468 if (list_is_last(&iter
->table
->link
, &ddebug_tables
)) {
472 iter
->table
= list_entry(iter
->table
->link
.next
,
473 struct ddebug_table
, link
);
475 return &iter
->table
->ddebugs
[iter
->idx
];
479 * Seq_ops start method. Called at the start of every
480 * read() call from userspace. Takes the ddebug_lock and
481 * seeks the seq_file's iterator to the given position.
483 static void *ddebug_proc_start(struct seq_file
*m
, loff_t
*pos
)
485 struct ddebug_iter
*iter
= m
->private;
490 printk(KERN_INFO
"%s: called m=%p *pos=%lld\n",
491 __func__
, m
, (unsigned long long)*pos
);
493 mutex_lock(&ddebug_lock
);
496 return SEQ_START_TOKEN
;
499 dp
= ddebug_iter_first(iter
);
500 while (dp
!= NULL
&& --n
> 0)
501 dp
= ddebug_iter_next(iter
);
506 * Seq_ops next method. Called several times within a read()
507 * call from userspace, with ddebug_lock held. Walks to the
508 * next _ddebug object with a special case for the header line.
510 static void *ddebug_proc_next(struct seq_file
*m
, void *p
, loff_t
*pos
)
512 struct ddebug_iter
*iter
= m
->private;
516 printk(KERN_INFO
"%s: called m=%p p=%p *pos=%lld\n",
517 __func__
, m
, p
, (unsigned long long)*pos
);
519 if (p
== SEQ_START_TOKEN
)
520 dp
= ddebug_iter_first(iter
);
522 dp
= ddebug_iter_next(iter
);
528 * Seq_ops show method. Called several times within a read()
529 * call from userspace, with ddebug_lock held. Formats the
530 * current _ddebug as a single human-readable line, with a
531 * special case for the header line.
533 static int ddebug_proc_show(struct seq_file
*m
, void *p
)
535 struct ddebug_iter
*iter
= m
->private;
536 struct _ddebug
*dp
= p
;
540 printk(KERN_INFO
"%s: called m=%p p=%p\n",
543 if (p
== SEQ_START_TOKEN
) {
545 "# filename:lineno [module]function flags format\n");
549 seq_printf(m
, "%s:%u [%s]%s %s \"",
550 dp
->filename
, dp
->lineno
,
551 iter
->table
->mod_name
, dp
->function
,
552 ddebug_describe_flags(dp
, flagsbuf
, sizeof(flagsbuf
)));
553 seq_escape(m
, dp
->format
, "\t\r\n\"");
560 * Seq_ops stop method. Called at the end of each read()
561 * call from userspace. Drops ddebug_lock.
563 static void ddebug_proc_stop(struct seq_file
*m
, void *p
)
566 printk(KERN_INFO
"%s: called m=%p p=%p\n",
568 mutex_unlock(&ddebug_lock
);
571 static const struct seq_operations ddebug_proc_seqops
= {
572 .start
= ddebug_proc_start
,
573 .next
= ddebug_proc_next
,
574 .show
= ddebug_proc_show
,
575 .stop
= ddebug_proc_stop
579 * File_ops->open method for <debugfs>/dynamic_debug/control. Does the seq_file
580 * setup dance, and also creates an iterator to walk the _ddebugs.
581 * Note that we create a seq_file always, even for O_WRONLY files
582 * where it's not needed, as doing so simplifies the ->release method.
584 static int ddebug_proc_open(struct inode
*inode
, struct file
*file
)
586 struct ddebug_iter
*iter
;
590 printk(KERN_INFO
"%s: called\n", __func__
);
592 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
596 err
= seq_open(file
, &ddebug_proc_seqops
);
601 ((struct seq_file
*) file
->private_data
)->private = iter
;
605 static const struct file_operations ddebug_proc_fops
= {
606 .owner
= THIS_MODULE
,
607 .open
= ddebug_proc_open
,
610 .release
= seq_release_private
,
611 .write
= ddebug_proc_write
615 * Allocate a new ddebug_table for the given module
616 * and add it to the global list.
618 int ddebug_add_module(struct _ddebug
*tab
, unsigned int n
,
621 struct ddebug_table
*dt
;
624 dt
= kzalloc(sizeof(*dt
), GFP_KERNEL
);
627 new_name
= kstrdup(name
, GFP_KERNEL
);
628 if (new_name
== NULL
) {
632 dt
->mod_name
= new_name
;
637 mutex_lock(&ddebug_lock
);
638 list_add_tail(&dt
->link
, &ddebug_tables
);
639 mutex_unlock(&ddebug_lock
);
642 printk(KERN_INFO
"%u debug prints in module %s\n",
646 EXPORT_SYMBOL_GPL(ddebug_add_module
);
648 static void ddebug_table_free(struct ddebug_table
*dt
)
650 list_del_init(&dt
->link
);
656 * Called in response to a module being unloaded. Removes
657 * any ddebug_table's which point at the module.
659 int ddebug_remove_module(const char *mod_name
)
661 struct ddebug_table
*dt
, *nextdt
;
665 printk(KERN_INFO
"%s: removing module \"%s\"\n",
668 mutex_lock(&ddebug_lock
);
669 list_for_each_entry_safe(dt
, nextdt
, &ddebug_tables
, link
) {
670 if (!strcmp(dt
->mod_name
, mod_name
)) {
671 ddebug_table_free(dt
);
675 mutex_unlock(&ddebug_lock
);
678 EXPORT_SYMBOL_GPL(ddebug_remove_module
);
680 static void ddebug_remove_all_tables(void)
682 mutex_lock(&ddebug_lock
);
683 while (!list_empty(&ddebug_tables
)) {
684 struct ddebug_table
*dt
= list_entry(ddebug_tables
.next
,
687 ddebug_table_free(dt
);
689 mutex_unlock(&ddebug_lock
);
692 static int __init
dynamic_debug_init(void)
694 struct dentry
*dir
, *file
;
695 struct _ddebug
*iter
, *iter_start
;
696 const char *modname
= NULL
;
700 dir
= debugfs_create_dir("dynamic_debug", NULL
);
703 file
= debugfs_create_file("control", 0644, dir
, NULL
,
709 if (__start___verbose
!= __stop___verbose
) {
710 iter
= __start___verbose
;
711 modname
= iter
->modname
;
713 for (; iter
< __stop___verbose
; iter
++) {
714 if (strcmp(modname
, iter
->modname
)) {
715 ret
= ddebug_add_module(iter_start
, n
, modname
);
719 modname
= iter
->modname
;
724 ret
= ddebug_add_module(iter_start
, n
, modname
);
728 ddebug_remove_all_tables();
730 debugfs_remove(file
);
734 module_init(dynamic_debug_init
);