4 * Builtin probe command: Set up probe events by C expression
6 * Written by Masami Hiramatsu <mhiramat@redhat.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
24 #include <sys/utsname.h>
25 #include <sys/types.h>
37 #include "util/util.h"
38 #include "util/event.h"
39 #include "util/debug.h"
40 #include "util/parse-options.h"
41 #include "util/parse-events.h" /* For debugfs_path */
42 #include "util/probe-finder.h"
44 /* Default vmlinux search paths */
45 #define NR_SEARCH_PATH 3
46 const char *default_search_path
[NR_SEARCH_PATH
] = {
47 "/lib/modules/%s/build/vmlinux", /* Custom build kernel */
48 "/usr/lib/debug/lib/modules/%s/vmlinux", /* Red Hat debuginfo */
49 "/boot/vmlinux-debug-%s", /* Ubuntu */
52 #define MAX_PATH_LEN 256
53 #define MAX_PROBES 128
54 #define MAX_PROBE_ARGS 128
55 #define PERFPROBE_GROUP "probe"
57 /* Session management structure */
63 struct probe_point probes
[MAX_PROBES
];
66 #define semantic_error(msg ...) die("Semantic error :" msg)
68 /* Parse probe point. Return 1 if return probe */
69 static void parse_probe_point(char *arg
, struct probe_point
*pp
)
76 * perf probe FUNC[+OFFS|%return][@SRC]
79 ptr
= strpbrk(arg
, ":+@%");
85 /* Check arg is function or file and copy it */
86 if (strchr(arg
, '.')) /* File */
87 pp
->file
= strdup(arg
);
89 pp
->function
= strdup(arg
);
90 DIE_IF(pp
->file
== NULL
&& pp
->function
== NULL
);
92 /* Parse other options */
96 ptr
= strpbrk(arg
, ":+@%");
102 case ':': /* Line number */
103 pp
->line
= strtoul(arg
, &tmp
, 0);
105 semantic_error("There is non-digit charactor"
108 case '+': /* Byte offset from a symbol */
109 pp
->offset
= strtoul(arg
, &tmp
, 0);
111 semantic_error("There is non-digit charactor"
114 case '@': /* File name */
116 semantic_error("SRC@SRC is not allowed.");
117 pp
->file
= strdup(arg
);
118 DIE_IF(pp
->file
== NULL
);
120 semantic_error("@SRC must be the last "
123 case '%': /* Probe places */
124 if (strcmp(arg
, "return") == 0) {
126 } else /* Others not supported yet */
127 semantic_error("%%%s is not supported.", arg
);
130 DIE_IF("Program has a bug.");
135 /* Exclusion check */
136 if (pp
->line
&& pp
->offset
)
137 semantic_error("Offset can't be used with line number.");
138 if (!pp
->line
&& pp
->file
&& !pp
->function
)
139 semantic_error("File always requires line number.");
140 if (pp
->offset
&& !pp
->function
)
141 semantic_error("Offset requires an entry function.");
142 if (pp
->retprobe
&& !pp
->function
)
143 semantic_error("Return probe requires an entry function.");
144 if ((pp
->offset
|| pp
->line
) && pp
->retprobe
)
145 semantic_error("Offset/Line can't be used with return probe.");
147 pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",
148 pp
->function
, pp
->file
, pp
->line
, pp
->offset
, pp
->retprobe
);
151 /* Parse an event definition. Note that any error must die. */
152 static void parse_probe_event(const char *str
)
154 char *argv
[MAX_PROBE_ARGS
+ 2]; /* Event + probe + args */
156 struct probe_point
*pp
= &session
.probes
[session
.nr_probe
];
158 pr_debug("probe-definition(%d): %s\n", session
.nr_probe
, str
);
159 if (++session
.nr_probe
== MAX_PROBES
)
160 semantic_error("Too many probes");
162 /* Separate arguments, similar to argv_split */
165 /* Skip separators */
166 while (isspace(*str
))
169 /* Add an argument */
173 /* Skip the argument */
174 while (!isspace(*str
) && *str
!= '\0')
177 /* Duplicate the argument */
178 argv
[argc
] = strndup(s
, str
- s
);
179 if (argv
[argc
] == NULL
)
181 if (++argc
== MAX_PROBE_ARGS
)
182 semantic_error("Too many arguments");
183 pr_debug("argv[%d]=%s\n", argc
, argv
[argc
- 1]);
185 } while (*str
!= '\0');
187 semantic_error("An empty argument.");
189 /* Parse probe point */
190 parse_probe_point(argv
[0], pp
);
192 if (pp
->file
|| pp
->line
)
193 session
.need_dwarf
= 1;
196 pp
->nr_args
= argc
- 1;
197 if (pp
->nr_args
> 0) {
198 pp
->args
= (char **)malloc(sizeof(char *) * pp
->nr_args
);
201 memcpy(pp
->args
, &argv
[1], sizeof(char *) * pp
->nr_args
);
204 /* Ensure return probe has no C argument */
205 for (i
= 0; i
< pp
->nr_args
; i
++)
206 if (is_c_varname(pp
->args
[i
])) {
208 semantic_error("You can't specify local"
209 " variable for kretprobe");
210 session
.need_dwarf
= 1;
213 pr_debug("%d arguments\n", pp
->nr_args
);
216 static int opt_add_probe_event(const struct option
*opt __used
,
217 const char *str
, int unset __used
)
220 parse_probe_event(str
);
225 static int open_default_vmlinux(void)
228 char fname
[MAX_PATH_LEN
];
233 pr_debug("uname() failed.\n");
236 session
.release
= uts
.release
;
237 for (i
= 0; i
< NR_SEARCH_PATH
; i
++) {
238 ret
= snprintf(fname
, MAX_PATH_LEN
,
239 default_search_path
[i
], session
.release
);
240 if (ret
>= MAX_PATH_LEN
|| ret
< 0) {
241 pr_debug("Filename(%d,%s) is too long.\n", i
,
246 pr_debug("try to open %s\n", fname
);
247 fd
= open(fname
, O_RDONLY
);
255 static const char * const probe_usage
[] = {
256 "perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
257 "perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
261 static const struct option options
[] = {
262 OPT_BOOLEAN('v', "verbose", &verbose
,
263 "be more verbose (show parsed arguments, etc)"),
265 OPT_STRING('k', "vmlinux", &session
.vmlinux
, "file",
266 "vmlinux/module pathname"),
268 OPT_CALLBACK('a', "add", NULL
,
270 "FUNC[+OFFS|%return] [ARG ...]",
272 "FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",
274 "probe point definition, where\n"
275 "\t\tGRP:\tGroup name (optional)\n"
276 "\t\tNAME:\tEvent name\n"
277 "\t\tFUNC:\tFunction name\n"
278 "\t\tOFFS:\tOffset from function entry (in byte)\n"
279 "\t\t%return:\tPut the probe at function return\n"
281 "\t\tARG:\tProbe argument (only \n"
283 "\t\tSRC:\tSource code path\n"
284 "\t\tRLN:\tRelative line number from function entry.\n"
285 "\t\tALN:\tAbsolute line number in file.\n"
286 "\t\tARG:\tProbe argument (local variable name or\n"
288 "\t\t\tkprobe-tracer argument format is supported.)\n",
289 opt_add_probe_event
),
293 static int write_new_event(int fd
, const char *buf
)
297 ret
= write(fd
, buf
, strlen(buf
));
299 die("Failed to create event.");
301 printf("Added new event: %s\n", buf
);
306 #define MAX_CMDLEN 256
308 static int synthesize_probe_event(struct probe_point
*pp
)
312 pp
->probes
[0] = buf
= (char *)calloc(MAX_CMDLEN
, sizeof(char));
314 die("Failed to allocate memory by calloc.");
315 ret
= snprintf(buf
, MAX_CMDLEN
, "%s+%d", pp
->function
, pp
->offset
);
316 if (ret
<= 0 || ret
>= MAX_CMDLEN
)
320 for (i
= 0; i
< pp
->nr_args
; i
++) {
321 ret
= snprintf(&buf
[len
], MAX_CMDLEN
- len
, " %s",
323 if (ret
<= 0 || ret
>= MAX_CMDLEN
- len
)
336 int cmd_probe(int argc
, const char **argv
, const char *prefix __used
)
339 struct probe_point
*pp
;
340 char buf
[MAX_CMDLEN
];
342 argc
= parse_options(argc
, argv
, options
, probe_usage
,
343 PARSE_OPT_STOP_AT_NON_OPTION
);
344 for (i
= 0; i
< argc
; i
++)
345 parse_probe_event(argv
[i
]);
347 if (session
.nr_probe
== 0)
348 usage_with_options(probe_usage
, options
);
350 if (session
.need_dwarf
)
352 semantic_error("Debuginfo-analysis is not supported");
353 #else /* !NO_LIBDWARF */
354 pr_info("Some probes require debuginfo.\n");
357 fd
= open(session
.vmlinux
, O_RDONLY
);
359 fd
= open_default_vmlinux();
361 if (session
.need_dwarf
)
362 die("Could not open vmlinux/module file.");
364 pr_warning("Could not open vmlinux/module file."
365 " Try to use symbols.\n");
369 /* Searching probe points */
370 for (j
= 0; j
< session
.nr_probe
; j
++) {
371 pp
= &session
.probes
[j
];
375 lseek(fd
, SEEK_SET
, 0);
376 ret
= find_probepoint(fd
, pp
);
378 if (session
.need_dwarf
)
379 die("Could not analyze debuginfo.");
381 pr_warning("An error occurred in debuginfo analysis. Try to use symbols.\n");
384 if (ret
== 0) /* No error but failed to find probe point. */
385 die("No probe point found.");
390 #endif /* !NO_LIBDWARF */
392 /* Synthesize probes without dwarf */
393 for (j
= 0; j
< session
.nr_probe
; j
++) {
394 pp
= &session
.probes
[j
];
395 if (pp
->found
) /* This probe is already found. */
398 ret
= synthesize_probe_event(pp
);
400 semantic_error("probe point is too long.");
402 die("Failed to synthesize a probe point.");
405 /* Settng up probe points */
406 snprintf(buf
, MAX_CMDLEN
, "%s/../kprobe_events", debugfs_path
);
407 fd
= open(buf
, O_WRONLY
, O_APPEND
);
410 die("kprobe_events file does not exist - please rebuild with CONFIG_KPROBE_TRACER.");
412 die("Could not open kprobe_events file: %s",
415 for (j
= 0; j
< session
.nr_probe
; j
++) {
416 pp
= &session
.probes
[j
];
417 if (pp
->found
== 1) {
418 snprintf(buf
, MAX_CMDLEN
, "%c:%s/%s_%x %s\n",
419 pp
->retprobe
? 'r' : 'p', PERFPROBE_GROUP
,
420 pp
->function
, pp
->offset
, pp
->probes
[0]);
421 write_new_event(fd
, buf
);
423 for (i
= 0; i
< pp
->found
; i
++) {
424 snprintf(buf
, MAX_CMDLEN
, "%c:%s/%s_%x_%d %s\n",
425 pp
->retprobe
? 'r' : 'p',
427 pp
->function
, pp
->offset
, i
,
429 write_new_event(fd
, buf
);