a1467d12547a15cff948b4eef33076680a17da59
[linux-2.6.git] / tools / perf / builtin-probe.c
1 /*
2  * builtin-probe.c
3  *
4  * Builtin probe command: Set up probe events by C expression
5  *
6  * Written by Masami Hiramatsu <mhiramat@redhat.com>
7  *
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.
12  *
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.
17  *
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.
21  *
22  */
23 #define _GNU_SOURCE
24 #include <sys/utsname.h>
25 #include <sys/types.h>
26 #include <sys/stat.h>
27 #include <fcntl.h>
28 #include <errno.h>
29 #include <stdio.h>
30 #include <unistd.h>
31 #include <stdlib.h>
32 #include <string.h>
33
34 #undef _GNU_SOURCE
35 #include "perf.h"
36 #include "builtin.h"
37 #include "util/util.h"
38 #include "util/parse-options.h"
39 #include "util/parse-events.h"  /* For debugfs_path */
40 #include "util/probe-finder.h"
41
42 /* Default vmlinux search paths */
43 #define NR_SEARCH_PATH 3
44 const char *default_search_path[NR_SEARCH_PATH] = {
45 "/lib/modules/%s/build/vmlinux",                /* Custom build kernel */
46 "/usr/lib/debug/lib/modules/%s/vmlinux",        /* Red Hat debuginfo */
47 "/boot/vmlinux-debug-%s",                       /* Ubuntu */
48 };
49
50 #define MAX_PATH_LEN 256
51 #define MAX_PROBES 128
52 #define MAX_PROBE_ARGS 128
53
54 /* Session management structure */
55 static struct {
56         char *vmlinux;
57         char *release;
58         int need_dwarf;
59         int nr_probe;
60         struct probe_point probes[MAX_PROBES];
61         char *events[MAX_PROBES];
62 } session;
63
64 #define semantic_error(msg ...) die("Semantic error :" msg)
65
66 static int parse_probepoint(const struct option *opt __used,
67                             const char *str, int unset __used)
68 {
69         char *argv[MAX_PROBE_ARGS + 2]; /* Event + probe + args */
70         int argc, i;
71         char *arg, *ptr;
72         struct probe_point *pp = &session.probes[session.nr_probe];
73         char **event = &session.events[session.nr_probe];
74         int retp = 0;
75
76         if (!str)       /* The end of probe points */
77                 return 0;
78
79         debug("Probe-define(%d): %s\n", session.nr_probe, str);
80         if (++session.nr_probe == MAX_PROBES)
81                 semantic_error("Too many probes");
82
83         /* Separate arguments, similar to argv_split */
84         argc = 0;
85         do {
86                 /* Skip separators */
87                 while (isspace(*str))
88                         str++;
89
90                 /* Add an argument */
91                 if (*str != '\0') {
92                         const char *s = str;
93
94                         /* Skip the argument */
95                         while (!isspace(*str) && *str != '\0')
96                                 str++;
97
98                         /* Duplicate the argument */
99                         argv[argc] = strndup(s, str - s);
100                         if (argv[argc] == NULL)
101                                 die("strndup");
102                         if (++argc == MAX_PROBE_ARGS)
103                                 semantic_error("Too many arguments");
104                         debug("argv[%d]=%s\n", argc, argv[argc - 1]);
105                 }
106         } while (*str != '\0');
107         if (argc < 2)
108                 semantic_error("Need event-name and probe-point at least.");
109
110         /* Parse the event name */
111         if (argv[0][0] == 'r')
112                 retp = 1;
113         else if (argv[0][0] != 'p')
114                 semantic_error("You must specify 'p'(kprobe) or"
115                                 " 'r'(kretprobe) first.");
116         /* TODO: check event name */
117         *event = argv[0];
118
119         /* Parse probe point */
120         arg = argv[1];
121         if (arg[0] == '@') {
122                 /* Source Line */
123                 arg++;
124                 ptr = strchr(arg, ':');
125                 if (!ptr || !isdigit(ptr[1]))
126                         semantic_error("Line number is required.");
127                 *ptr++ = '\0';
128                 if (strlen(arg) == 0)
129                         semantic_error("No file name.");
130                 pp->file = strdup(arg);
131                 pp->line = atoi(ptr);
132                 if (!pp->file || !pp->line)
133                         semantic_error("Failed to parse line.");
134                 debug("file:%s line:%d\n", pp->file, pp->line);
135         } else {
136                 /* Function name */
137                 ptr = strchr(arg, '+');
138                 if (ptr) {
139                         if (!isdigit(ptr[1]))
140                                 semantic_error("Offset is required.");
141                         *ptr++ = '\0';
142                         pp->offset = atoi(ptr);
143                 } else
144                         ptr = arg;
145                 ptr = strchr(ptr, '@');
146                 if (ptr) {
147                         *ptr++ = '\0';
148                         pp->file = strdup(ptr);
149                 }
150                 pp->function = strdup(arg);
151                 debug("symbol:%s file:%s offset:%d\n",
152                       pp->function, pp->file, pp->offset);
153         }
154         free(argv[1]);
155         if (pp->file)
156                 session.need_dwarf = 1;
157
158         /* Copy arguments */
159         pp->nr_args = argc - 2;
160         if (pp->nr_args > 0) {
161                 pp->args = (char **)malloc(sizeof(char *) * pp->nr_args);
162                 if (!pp->args)
163                         die("malloc");
164                 memcpy(pp->args, &argv[2], sizeof(char *) * pp->nr_args);
165         }
166
167         /* Ensure return probe has no C argument */
168         for (i = 0; i < pp->nr_args; i++)
169                 if (is_c_varname(pp->args[i])) {
170                         if (retp)
171                                 semantic_error("You can't specify local"
172                                                 " variable for kretprobe");
173                         session.need_dwarf = 1;
174                 }
175
176         debug("%d arguments\n", pp->nr_args);
177         return 0;
178 }
179
180 #ifndef NO_LIBDWARF
181 static int open_default_vmlinux(void)
182 {
183         struct utsname uts;
184         char fname[MAX_PATH_LEN];
185         int fd, ret, i;
186
187         ret = uname(&uts);
188         if (ret) {
189                 debug("uname() failed.\n");
190                 return -errno;
191         }
192         session.release = uts.release;
193         for (i = 0; i < NR_SEARCH_PATH; i++) {
194                 ret = snprintf(fname, MAX_PATH_LEN,
195                                default_search_path[i], session.release);
196                 if (ret >= MAX_PATH_LEN || ret < 0) {
197                         debug("Filename(%d,%s) is too long.\n", i, uts.release);
198                         errno = E2BIG;
199                         return -E2BIG;
200                 }
201                 debug("try to open %s\n", fname);
202                 fd = open(fname, O_RDONLY);
203                 if (fd >= 0)
204                         break;
205         }
206         return fd;
207 }
208 #endif
209
210 static const char * const probe_usage[] = {
211         "perf probe [<options>] -P 'PROBEDEF' [-P 'PROBEDEF' ...]",
212         NULL
213 };
214
215 static const struct option options[] = {
216 #ifndef NO_LIBDWARF
217         OPT_STRING('k', "vmlinux", &session.vmlinux, "file",
218                 "vmlinux/module pathname"),
219 #endif
220         OPT_CALLBACK('P', "probe", NULL,
221 #ifdef NO_LIBDWARF
222                 "p|r:[GRP/]NAME FUNC[+OFFS] [ARG ...]",
223 #else
224                 "p|r:[GRP/]NAME FUNC[+OFFS][@SRC]|@SRC:LINE [ARG ...]",
225 #endif
226                 "probe point definition, where\n"
227                 "\t\tp:\tkprobe probe\n"
228                 "\t\tr:\tkretprobe probe\n"
229                 "\t\tGRP:\tGroup name (optional)\n"
230                 "\t\tNAME:\tEvent name\n"
231                 "\t\tFUNC:\tFunction name\n"
232                 "\t\tOFFS:\tOffset from function entry (in byte)\n"
233 #ifdef NO_LIBDWARF
234                 "\t\tARG:\tProbe argument (only \n"
235 #else
236                 "\t\tSRC:\tSource code path\n"
237                 "\t\tLINE:\tLine number\n"
238                 "\t\tARG:\tProbe argument (local variable name or\n"
239 #endif
240                 "\t\t\tkprobe-tracer argument format is supported.)\n",
241                 parse_probepoint),
242         OPT_END()
243 };
244
245 static int write_new_event(int fd, const char *buf)
246 {
247         int ret;
248
249         printf("Adding new event: %s\n", buf);
250         ret = write(fd, buf, strlen(buf));
251         if (ret <= 0)
252                 die("failed to create event.");
253
254         return ret;
255 }
256
257 #define MAX_CMDLEN 256
258
259 static int synthesize_probepoint(struct probe_point *pp)
260 {
261         char *buf;
262         int i, len, ret;
263         pp->probes[0] = buf = (char *)calloc(MAX_CMDLEN, sizeof(char));
264         if (!buf)
265                 die("calloc");
266         ret = snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
267         if (ret <= 0 || ret >= MAX_CMDLEN)
268                 goto error;
269         len = ret;
270
271         for (i = 0; i < pp->nr_args; i++) {
272                 ret = snprintf(&buf[len], MAX_CMDLEN - len, " %s",
273                                pp->args[i]);
274                 if (ret <= 0 || ret >= MAX_CMDLEN - len)
275                         goto error;
276                 len += ret;
277         }
278         pp->found = 1;
279         return pp->found;
280 error:
281         free(pp->probes[0]);
282         if (ret > 0)
283                 ret = -E2BIG;
284         return ret;
285 }
286
287 int cmd_probe(int argc, const char **argv, const char *prefix __used)
288 {
289         int i, j, fd, ret;
290         struct probe_point *pp;
291         char buf[MAX_CMDLEN];
292
293         argc = parse_options(argc, argv, options, probe_usage,
294                 PARSE_OPT_STOP_AT_NON_OPTION);
295         if (argc || session.nr_probe == 0)
296                 usage_with_options(probe_usage, options);
297
298 #ifdef NO_LIBDWARF
299         if (session.need_dwarf)
300                 semantic_error("Dwarf-analysis is not supported");
301 #endif
302
303         /* Synthesize probes without dwarf */
304         for (j = 0; j < session.nr_probe; j++) {
305 #ifndef NO_LIBDWARF
306                 if (session.events[j][0] != 'r') {
307                         session.need_dwarf = 1;
308                         continue;
309                 }
310 #endif
311                 ret = synthesize_probepoint(&session.probes[j]);
312                 if (ret == -E2BIG)
313                         semantic_error("probe point is too long.");
314                 else if (ret < 0)
315                         die("snprintf");
316         }
317
318 #ifndef NO_LIBDWARF
319         if (!session.need_dwarf)
320                 goto setup_probes;
321
322         if (session.vmlinux)
323                 fd = open(session.vmlinux, O_RDONLY);
324         else
325                 fd = open_default_vmlinux();
326         if (fd < 0)
327                 die("vmlinux/module file open");
328
329         /* Searching probe points */
330         for (j = 0; j < session.nr_probe; j++) {
331                 pp = &session.probes[j];
332                 if (pp->found)
333                         continue;
334
335                 lseek(fd, SEEK_SET, 0);
336                 ret = find_probepoint(fd, pp);
337                 if (ret <= 0)
338                         die("No probe point found.\n");
339                 debug("probe event %s found\n", session.events[j]);
340         }
341         close(fd);
342
343 setup_probes:
344 #endif /* !NO_LIBDWARF */
345
346         /* Settng up probe points */
347         snprintf(buf, MAX_CMDLEN, "%s/../kprobe_events", debugfs_path);
348         fd = open(buf, O_WRONLY, O_APPEND);
349         if (fd < 0)
350                 die("kprobe_events open");
351         for (j = 0; j < session.nr_probe; j++) {
352                 pp = &session.probes[j];
353                 if (pp->found == 1) {
354                         snprintf(buf, MAX_CMDLEN, "%s %s\n",
355                                 session.events[j], pp->probes[0]);
356                         write_new_event(fd, buf);
357                 } else
358                         for (i = 0; i < pp->found; i++) {
359                                 snprintf(buf, MAX_CMDLEN, "%s%d %s\n",
360                                         session.events[j], i, pp->probes[i]);
361                                 write_new_event(fd, buf);
362                         }
363         }
364         close(fd);
365         return 0;
366 }
367