7e741f54d7986a15f72a97c9eb4f684f33f23e6f
[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/strlist.h"
39 #include "util/event.h"
40 #include "util/debug.h"
41 #include "util/symbol.h"
42 #include "util/thread.h"
43 #include "util/session.h"
44 #include "util/parse-options.h"
45 #include "util/parse-events.h"  /* For debugfs_path */
46 #include "util/probe-finder.h"
47 #include "util/probe-event.h"
48
49 #define MAX_PATH_LEN 256
50 #define MAX_PROBES 128
51
52 /* Session management structure */
53 static struct {
54         bool need_dwarf;
55         bool list_events;
56         bool force_add;
57         int nr_probe;
58         struct probe_point probes[MAX_PROBES];
59         struct strlist *dellist;
60         struct perf_session *psession;
61         struct map *kmap;
62 } session;
63
64
65 /* Parse an event definition. Note that any error must die. */
66 static void parse_probe_event(const char *str)
67 {
68         struct probe_point *pp = &session.probes[session.nr_probe];
69
70         pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
71         if (++session.nr_probe == MAX_PROBES)
72                 die("Too many probes (> %d) are specified.", MAX_PROBES);
73
74         /* Parse perf-probe event into probe_point */
75         parse_perf_probe_event(str, pp, &session.need_dwarf);
76
77         pr_debug("%d arguments\n", pp->nr_args);
78 }
79
80 static void parse_probe_event_argv(int argc, const char **argv)
81 {
82         int i, len;
83         char *buf;
84
85         /* Bind up rest arguments */
86         len = 0;
87         for (i = 0; i < argc; i++)
88                 len += strlen(argv[i]) + 1;
89         buf = zalloc(len + 1);
90         if (!buf)
91                 die("Failed to allocate memory for binding arguments.");
92         len = 0;
93         for (i = 0; i < argc; i++)
94                 len += sprintf(&buf[len], "%s ", argv[i]);
95         parse_probe_event(buf);
96         free(buf);
97 }
98
99 static int opt_add_probe_event(const struct option *opt __used,
100                               const char *str, int unset __used)
101 {
102         if (str)
103                 parse_probe_event(str);
104         return 0;
105 }
106
107 static int opt_del_probe_event(const struct option *opt __used,
108                                const char *str, int unset __used)
109 {
110         if (str) {
111                 if (!session.dellist)
112                         session.dellist = strlist__new(true, NULL);
113                 strlist__add(session.dellist, str);
114         }
115         return 0;
116 }
117
118 /* Currently just checking function name from symbol map */
119 static void evaluate_probe_point(struct probe_point *pp)
120 {
121         struct symbol *sym;
122         sym = map__find_symbol_by_name(session.kmap, pp->function,
123                                        session.psession, NULL);
124         if (!sym)
125                 die("Kernel symbol \'%s\' not found - probe not added.",
126                     pp->function);
127 }
128
129 #ifndef NO_LIBDWARF
130 static int open_vmlinux(void)
131 {
132         if (map__load(session.kmap, session.psession, NULL) < 0) {
133                 pr_debug("Failed to load kernel map.\n");
134                 return -EINVAL;
135         }
136         pr_debug("Try to open %s\n", session.kmap->dso->long_name);
137         return open(session.kmap->dso->long_name, O_RDONLY);
138 }
139 #endif
140
141 static const char * const probe_usage[] = {
142         "perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
143         "perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
144         "perf probe [<options>] --del '[GROUP:]EVENT' ...",
145         "perf probe --list",
146         NULL
147 };
148
149 static const struct option options[] = {
150         OPT_BOOLEAN('v', "verbose", &verbose,
151                     "be more verbose (show parsed arguments, etc)"),
152 #ifndef NO_LIBDWARF
153         OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
154                    "file", "vmlinux pathname"),
155 #endif
156         OPT_BOOLEAN('l', "list", &session.list_events,
157                     "list up current probe events"),
158         OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.",
159                 opt_del_probe_event),
160         OPT_CALLBACK('a', "add", NULL,
161 #ifdef NO_LIBDWARF
162                 "[EVENT=]FUNC[+OFFS|%return] [ARG ...]",
163 #else
164                 "[EVENT=]FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",
165 #endif
166                 "probe point definition, where\n"
167                 "\t\tGROUP:\tGroup name (optional)\n"
168                 "\t\tEVENT:\tEvent name\n"
169                 "\t\tFUNC:\tFunction name\n"
170                 "\t\tOFFS:\tOffset from function entry (in byte)\n"
171                 "\t\t%return:\tPut the probe at function return\n"
172 #ifdef NO_LIBDWARF
173                 "\t\tARG:\tProbe argument (only \n"
174 #else
175                 "\t\tSRC:\tSource code path\n"
176                 "\t\tRLN:\tRelative line number from function entry.\n"
177                 "\t\tALN:\tAbsolute line number in file.\n"
178                 "\t\tARG:\tProbe argument (local variable name or\n"
179 #endif
180                 "\t\t\tkprobe-tracer argument format.)\n",
181                 opt_add_probe_event),
182         OPT_BOOLEAN('f', "force", &session.force_add, "forcibly add events"
183                     " with existing name"),
184         OPT_END()
185 };
186
187 int cmd_probe(int argc, const char **argv, const char *prefix __used)
188 {
189         int i, ret;
190 #ifndef NO_LIBDWARF
191         int fd;
192 #endif
193         struct probe_point *pp;
194
195         argc = parse_options(argc, argv, options, probe_usage,
196                              PARSE_OPT_STOP_AT_NON_OPTION);
197         if (argc > 0) {
198                 if (strcmp(argv[0], "-") == 0) {
199                         pr_warning("  Error: '-' is not supported.\n");
200                         usage_with_options(probe_usage, options);
201                 }
202                 parse_probe_event_argv(argc, argv);
203         }
204
205         if ((!session.nr_probe && !session.dellist && !session.list_events))
206                 usage_with_options(probe_usage, options);
207
208         if (session.list_events) {
209                 if (session.nr_probe != 0 || session.dellist) {
210                         pr_warning("  Error: Don't use --list with"
211                                    " --add/--del.\n");
212                         usage_with_options(probe_usage, options);
213                 }
214                 show_perf_probe_events();
215                 return 0;
216         }
217
218         if (session.dellist) {
219                 del_trace_kprobe_events(session.dellist);
220                 strlist__delete(session.dellist);
221                 if (session.nr_probe == 0)
222                         return 0;
223         }
224
225         /* Initialize symbol maps for vmlinux */
226         symbol_conf.sort_by_name = true;
227         if (symbol_conf.vmlinux_name == NULL)
228                 symbol_conf.try_vmlinux_path = true;
229         if (symbol__init() < 0)
230                 die("Failed to init symbol map.");
231         session.psession = perf_session__new(NULL, O_WRONLY, false);
232         if (session.psession == NULL)
233                 die("Failed to init perf_session.");
234         session.kmap = map_groups__find_by_name(&session.psession->kmaps,
235                                                 MAP__FUNCTION,
236                                                 "[kernel.kallsyms]");
237         if (!session.kmap)
238                 die("Could not find kernel map.\n");
239
240         if (session.need_dwarf)
241 #ifdef NO_LIBDWARF
242                 die("Debuginfo-analysis is not supported");
243 #else   /* !NO_LIBDWARF */
244                 pr_debug("Some probes require debuginfo.\n");
245
246         fd = open_vmlinux();
247         if (fd < 0) {
248                 if (session.need_dwarf)
249                         die("Could not open debuginfo file.");
250
251                 pr_debug("Could not open vmlinux/module file."
252                          " Try to use symbols.\n");
253                 goto end_dwarf;
254         }
255
256         /* Searching probe points */
257         for (i = 0; i < session.nr_probe; i++) {
258                 pp = &session.probes[i];
259                 if (pp->found)
260                         continue;
261
262                 lseek(fd, SEEK_SET, 0);
263                 ret = find_probepoint(fd, pp);
264                 if (ret > 0)
265                         continue;
266                 if (ret == 0) { /* No error but failed to find probe point. */
267                         synthesize_perf_probe_point(pp);
268                         die("Probe point '%s' not found. - probe not added.",
269                             pp->probes[0]);
270                 }
271                 /* Error path */
272                 if (session.need_dwarf) {
273                         if (ret == -ENOENT)
274                                 pr_warning("No dwarf info found in the vmlinux - please rebuild with CONFIG_DEBUG_INFO=y.\n");
275                         die("Could not analyze debuginfo.");
276                 }
277                 pr_debug("An error occurred in debuginfo analysis."
278                          " Try to use symbols.\n");
279                 break;
280         }
281         close(fd);
282
283 end_dwarf:
284 #endif /* !NO_LIBDWARF */
285
286         /* Synthesize probes without dwarf */
287         for (i = 0; i < session.nr_probe; i++) {
288                 pp = &session.probes[i];
289                 if (pp->found)  /* This probe is already found. */
290                         continue;
291
292                 evaluate_probe_point(pp);
293                 ret = synthesize_trace_kprobe_event(pp);
294                 if (ret == -E2BIG)
295                         die("probe point definition becomes too long.");
296                 else if (ret < 0)
297                         die("Failed to synthesize a probe point.");
298         }
299
300         /* Settng up probe points */
301         add_trace_kprobe_events(session.probes, session.nr_probe,
302                                 session.force_add);
303         return 0;
304 }
305