perf: Use eprintf() for debug messages in perf-probe
[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/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"
43
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 */
50 };
51
52 #define MAX_PATH_LEN 256
53 #define MAX_PROBES 128
54 #define MAX_PROBE_ARGS 128
55
56 /* Session management structure */
57 static struct {
58         char *vmlinux;
59         char *release;
60         int need_dwarf;
61         int nr_probe;
62         struct probe_point probes[MAX_PROBES];
63         char *events[MAX_PROBES];
64 } session;
65
66 #define semantic_error(msg ...) die("Semantic error :" msg)
67
68 static int parse_probepoint(const struct option *opt __used,
69                             const char *str, int unset __used)
70 {
71         char *argv[MAX_PROBE_ARGS + 2]; /* Event + probe + args */
72         int argc, i;
73         char *arg, *ptr;
74         struct probe_point *pp = &session.probes[session.nr_probe];
75         char **event = &session.events[session.nr_probe];
76         int retp = 0;
77
78         if (!str)       /* The end of probe points */
79                 return 0;
80
81         eprintf("probe-definition(%d): %s\n", session.nr_probe, str);
82         if (++session.nr_probe == MAX_PROBES)
83                 semantic_error("Too many probes");
84
85         /* Separate arguments, similar to argv_split */
86         argc = 0;
87         do {
88                 /* Skip separators */
89                 while (isspace(*str))
90                         str++;
91
92                 /* Add an argument */
93                 if (*str != '\0') {
94                         const char *s = str;
95
96                         /* Skip the argument */
97                         while (!isspace(*str) && *str != '\0')
98                                 str++;
99
100                         /* Duplicate the argument */
101                         argv[argc] = strndup(s, str - s);
102                         if (argv[argc] == NULL)
103                                 die("strndup");
104                         if (++argc == MAX_PROBE_ARGS)
105                                 semantic_error("Too many arguments");
106                         eprintf("argv[%d]=%s\n", argc, argv[argc - 1]);
107                 }
108         } while (*str != '\0');
109         if (argc < 2)
110                 semantic_error("Need event-name and probe-point at least.");
111
112         /* Parse the event name */
113         if (argv[0][0] == 'r')
114                 retp = 1;
115         else if (argv[0][0] != 'p')
116                 semantic_error("You must specify 'p'(kprobe) or"
117                                 " 'r'(kretprobe) first.");
118         /* TODO: check event name */
119         *event = argv[0];
120
121         /* Parse probe point */
122         arg = argv[1];
123         if (arg[0] == '@') {
124                 /* Source Line */
125                 arg++;
126                 ptr = strchr(arg, ':');
127                 if (!ptr || !isdigit(ptr[1]))
128                         semantic_error("Line number is required.");
129                 *ptr++ = '\0';
130                 if (strlen(arg) == 0)
131                         semantic_error("No file name.");
132                 pp->file = strdup(arg);
133                 pp->line = atoi(ptr);
134                 if (!pp->file || !pp->line)
135                         semantic_error("Failed to parse line.");
136                 eprintf("file:%s line:%d\n", pp->file, pp->line);
137         } else {
138                 /* Function name */
139                 ptr = strchr(arg, '+');
140                 if (ptr) {
141                         if (!isdigit(ptr[1]))
142                                 semantic_error("Offset is required.");
143                         *ptr++ = '\0';
144                         pp->offset = atoi(ptr);
145                 } else
146                         ptr = arg;
147                 ptr = strchr(ptr, '@');
148                 if (ptr) {
149                         *ptr++ = '\0';
150                         pp->file = strdup(ptr);
151                 }
152                 pp->function = strdup(arg);
153                 eprintf("symbol:%s file:%s offset:%d\n",
154                       pp->function, pp->file, pp->offset);
155         }
156         free(argv[1]);
157         if (pp->file)
158                 session.need_dwarf = 1;
159
160         /* Copy arguments */
161         pp->nr_args = argc - 2;
162         if (pp->nr_args > 0) {
163                 pp->args = (char **)malloc(sizeof(char *) * pp->nr_args);
164                 if (!pp->args)
165                         die("malloc");
166                 memcpy(pp->args, &argv[2], sizeof(char *) * pp->nr_args);
167         }
168
169         /* Ensure return probe has no C argument */
170         for (i = 0; i < pp->nr_args; i++)
171                 if (is_c_varname(pp->args[i])) {
172                         if (retp)
173                                 semantic_error("You can't specify local"
174                                                 " variable for kretprobe");
175                         session.need_dwarf = 1;
176                 }
177
178         eprintf("%d arguments\n", pp->nr_args);
179         return 0;
180 }
181
182 #ifndef NO_LIBDWARF
183 static int open_default_vmlinux(void)
184 {
185         struct utsname uts;
186         char fname[MAX_PATH_LEN];
187         int fd, ret, i;
188
189         ret = uname(&uts);
190         if (ret) {
191                 eprintf("uname() failed.\n");
192                 return -errno;
193         }
194         session.release = uts.release;
195         for (i = 0; i < NR_SEARCH_PATH; i++) {
196                 ret = snprintf(fname, MAX_PATH_LEN,
197                                default_search_path[i], session.release);
198                 if (ret >= MAX_PATH_LEN || ret < 0) {
199                         eprintf("Filename(%d,%s) is too long.\n", i,
200                                 uts.release);
201                         errno = E2BIG;
202                         return -E2BIG;
203                 }
204                 eprintf("try to open %s\n", fname);
205                 fd = open(fname, O_RDONLY);
206                 if (fd >= 0)
207                         break;
208         }
209         return fd;
210 }
211 #endif
212
213 static const char * const probe_usage[] = {
214         "perf probe [<options>] -P 'PROBEDEF' [-P 'PROBEDEF' ...]",
215         NULL
216 };
217
218 static const struct option options[] = {
219         OPT_BOOLEAN('v', "verbose", &verbose,
220                     "be more verbose (show parsed arguments, etc)"),
221 #ifndef NO_LIBDWARF
222         OPT_STRING('k', "vmlinux", &session.vmlinux, "file",
223                 "vmlinux/module pathname"),
224 #endif
225         OPT_CALLBACK('P', "probe", NULL,
226 #ifdef NO_LIBDWARF
227                 "p|r:[GRP/]NAME FUNC[+OFFS] [ARG ...]",
228 #else
229                 "p|r:[GRP/]NAME FUNC[+OFFS][@SRC]|@SRC:LINE [ARG ...]",
230 #endif
231                 "probe point definition, where\n"
232                 "\t\tp:\tkprobe probe\n"
233                 "\t\tr:\tkretprobe probe\n"
234                 "\t\tGRP:\tGroup name (optional)\n"
235                 "\t\tNAME:\tEvent name\n"
236                 "\t\tFUNC:\tFunction name\n"
237                 "\t\tOFFS:\tOffset from function entry (in byte)\n"
238 #ifdef NO_LIBDWARF
239                 "\t\tARG:\tProbe argument (only \n"
240 #else
241                 "\t\tSRC:\tSource code path\n"
242                 "\t\tLINE:\tLine number\n"
243                 "\t\tARG:\tProbe argument (local variable name or\n"
244 #endif
245                 "\t\t\tkprobe-tracer argument format is supported.)\n",
246                 parse_probepoint),
247         OPT_END()
248 };
249
250 static int write_new_event(int fd, const char *buf)
251 {
252         int ret;
253
254         printf("Adding new event: %s\n", buf);
255         ret = write(fd, buf, strlen(buf));
256         if (ret <= 0)
257                 die("failed to create event.");
258
259         return ret;
260 }
261
262 #define MAX_CMDLEN 256
263
264 static int synthesize_probepoint(struct probe_point *pp)
265 {
266         char *buf;
267         int i, len, ret;
268         pp->probes[0] = buf = (char *)calloc(MAX_CMDLEN, sizeof(char));
269         if (!buf)
270                 die("calloc");
271         ret = snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
272         if (ret <= 0 || ret >= MAX_CMDLEN)
273                 goto error;
274         len = ret;
275
276         for (i = 0; i < pp->nr_args; i++) {
277                 ret = snprintf(&buf[len], MAX_CMDLEN - len, " %s",
278                                pp->args[i]);
279                 if (ret <= 0 || ret >= MAX_CMDLEN - len)
280                         goto error;
281                 len += ret;
282         }
283         pp->found = 1;
284         return pp->found;
285 error:
286         free(pp->probes[0]);
287         if (ret > 0)
288                 ret = -E2BIG;
289         return ret;
290 }
291
292 int cmd_probe(int argc, const char **argv, const char *prefix __used)
293 {
294         int i, j, fd, ret;
295         struct probe_point *pp;
296         char buf[MAX_CMDLEN];
297
298         argc = parse_options(argc, argv, options, probe_usage,
299                 PARSE_OPT_STOP_AT_NON_OPTION);
300         if (argc || session.nr_probe == 0)
301                 usage_with_options(probe_usage, options);
302
303 #ifdef NO_LIBDWARF
304         if (session.need_dwarf)
305                 semantic_error("Dwarf-analysis is not supported");
306 #endif
307
308         /* Synthesize probes without dwarf */
309         for (j = 0; j < session.nr_probe; j++) {
310 #ifndef NO_LIBDWARF
311                 if (session.events[j][0] != 'r') {
312                         session.need_dwarf = 1;
313                         continue;
314                 }
315 #endif
316                 ret = synthesize_probepoint(&session.probes[j]);
317                 if (ret == -E2BIG)
318                         semantic_error("probe point is too long.");
319                 else if (ret < 0)
320                         die("snprintf");
321         }
322
323 #ifndef NO_LIBDWARF
324         if (!session.need_dwarf)
325                 goto setup_probes;
326
327         if (session.vmlinux)
328                 fd = open(session.vmlinux, O_RDONLY);
329         else
330                 fd = open_default_vmlinux();
331         if (fd < 0)
332                 die("vmlinux/module file open");
333
334         /* Searching probe points */
335         for (j = 0; j < session.nr_probe; j++) {
336                 pp = &session.probes[j];
337                 if (pp->found)
338                         continue;
339
340                 lseek(fd, SEEK_SET, 0);
341                 ret = find_probepoint(fd, pp);
342                 if (ret <= 0)
343                         die("No probe point found.\n");
344                 eprintf("probe event %s found\n", session.events[j]);
345         }
346         close(fd);
347
348 setup_probes:
349 #endif /* !NO_LIBDWARF */
350
351         /* Settng up probe points */
352         snprintf(buf, MAX_CMDLEN, "%s/../kprobe_events", debugfs_path);
353         fd = open(buf, O_WRONLY, O_APPEND);
354         if (fd < 0)
355                 die("kprobe_events open");
356         for (j = 0; j < session.nr_probe; j++) {
357                 pp = &session.probes[j];
358                 if (pp->found == 1) {
359                         snprintf(buf, MAX_CMDLEN, "%s %s\n",
360                                 session.events[j], pp->probes[0]);
361                         write_new_event(fd, buf);
362                 } else
363                         for (i = 0; i < pp->found; i++) {
364                                 snprintf(buf, MAX_CMDLEN, "%s%d %s\n",
365                                         session.events[j], i, pp->probes[i]);
366                                 write_new_event(fd, buf);
367                         }
368         }
369         close(fd);
370         return 0;
371 }
372