perf probe: Don't use a perf_session instance just to resolve symbols
[deliverable/linux.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/debugfs.h"
42 #include "util/symbol.h"
43 #include "util/thread.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 bool show_lines;
58 int nr_probe;
59 struct probe_point probes[MAX_PROBES];
60 struct strlist *dellist;
61 struct map_groups kmap_groups;
62 struct map *kmaps[MAP__NR_TYPES];
63 struct line_range line_range;
64 } session;
65
66
67 /* Parse an event definition. Note that any error must die. */
68 static void parse_probe_event(const char *str)
69 {
70 struct probe_point *pp = &session.probes[session.nr_probe];
71
72 pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
73 if (++session.nr_probe == MAX_PROBES)
74 die("Too many probes (> %d) are specified.", MAX_PROBES);
75
76 /* Parse perf-probe event into probe_point */
77 parse_perf_probe_event(str, pp, &session.need_dwarf);
78
79 pr_debug("%d arguments\n", pp->nr_args);
80 }
81
82 static void parse_probe_event_argv(int argc, const char **argv)
83 {
84 int i, len;
85 char *buf;
86
87 /* Bind up rest arguments */
88 len = 0;
89 for (i = 0; i < argc; i++)
90 len += strlen(argv[i]) + 1;
91 buf = zalloc(len + 1);
92 if (!buf)
93 die("Failed to allocate memory for binding arguments.");
94 len = 0;
95 for (i = 0; i < argc; i++)
96 len += sprintf(&buf[len], "%s ", argv[i]);
97 parse_probe_event(buf);
98 free(buf);
99 }
100
101 static int opt_add_probe_event(const struct option *opt __used,
102 const char *str, int unset __used)
103 {
104 if (str)
105 parse_probe_event(str);
106 return 0;
107 }
108
109 static int opt_del_probe_event(const struct option *opt __used,
110 const char *str, int unset __used)
111 {
112 if (str) {
113 if (!session.dellist)
114 session.dellist = strlist__new(true, NULL);
115 strlist__add(session.dellist, str);
116 }
117 return 0;
118 }
119
120 /* Currently just checking function name from symbol map */
121 static void evaluate_probe_point(struct probe_point *pp)
122 {
123 struct symbol *sym;
124 sym = map__find_symbol_by_name(session.kmaps[MAP__FUNCTION],
125 pp->function, NULL);
126 if (!sym)
127 die("Kernel symbol \'%s\' not found - probe not added.",
128 pp->function);
129 }
130
131 #ifndef NO_LIBDWARF
132 static int open_vmlinux(void)
133 {
134 if (map__load(session.kmaps[MAP__FUNCTION], NULL) < 0) {
135 pr_debug("Failed to load kernel map.\n");
136 return -EINVAL;
137 }
138 pr_debug("Try to open %s\n",
139 session.kmaps[MAP__FUNCTION]->dso->long_name);
140 return open(session.kmaps[MAP__FUNCTION]->dso->long_name, O_RDONLY);
141 }
142
143 static int opt_show_lines(const struct option *opt __used,
144 const char *str, int unset __used)
145 {
146 if (str)
147 parse_line_range_desc(str, &session.line_range);
148 INIT_LIST_HEAD(&session.line_range.line_list);
149 session.show_lines = true;
150 return 0;
151 }
152 #endif
153
154 static const char * const probe_usage[] = {
155 "perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
156 "perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
157 "perf probe [<options>] --del '[GROUP:]EVENT' ...",
158 "perf probe --list",
159 "perf probe --line 'LINEDESC'",
160 NULL
161 };
162
163 static const struct option options[] = {
164 OPT_BOOLEAN('v', "verbose", &verbose,
165 "be more verbose (show parsed arguments, etc)"),
166 #ifndef NO_LIBDWARF
167 OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
168 "file", "vmlinux pathname"),
169 #endif
170 OPT_BOOLEAN('l', "list", &session.list_events,
171 "list up current probe events"),
172 OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.",
173 opt_del_probe_event),
174 OPT_CALLBACK('a', "add", NULL,
175 #ifdef NO_LIBDWARF
176 "[EVENT=]FUNC[+OFFS|%return] [ARG ...]",
177 #else
178 "[EVENT=]FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",
179 #endif
180 "probe point definition, where\n"
181 "\t\tGROUP:\tGroup name (optional)\n"
182 "\t\tEVENT:\tEvent name\n"
183 "\t\tFUNC:\tFunction name\n"
184 "\t\tOFFS:\tOffset from function entry (in byte)\n"
185 "\t\t%return:\tPut the probe at function return\n"
186 #ifdef NO_LIBDWARF
187 "\t\tARG:\tProbe argument (only \n"
188 #else
189 "\t\tSRC:\tSource code path\n"
190 "\t\tRLN:\tRelative line number from function entry.\n"
191 "\t\tALN:\tAbsolute line number in file.\n"
192 "\t\tARG:\tProbe argument (local variable name or\n"
193 #endif
194 "\t\t\tkprobe-tracer argument format.)\n",
195 opt_add_probe_event),
196 OPT_BOOLEAN('f', "force", &session.force_add, "forcibly add events"
197 " with existing name"),
198 #ifndef NO_LIBDWARF
199 OPT_CALLBACK('L', "line", NULL,
200 "FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]",
201 "Show source code lines.", opt_show_lines),
202 #endif
203 OPT_END()
204 };
205
206 /* Initialize symbol maps for vmlinux */
207 static void init_vmlinux(void)
208 {
209 symbol_conf.sort_by_name = true;
210 if (symbol_conf.vmlinux_name == NULL)
211 symbol_conf.try_vmlinux_path = true;
212 else
213 pr_debug("Use vmlinux: %s\n", symbol_conf.vmlinux_name);
214 if (symbol__init() < 0)
215 die("Failed to init symbol map.");
216
217 map_groups__init(&session.kmap_groups);
218 if (map_groups__create_kernel_maps(&session.kmap_groups,
219 session.kmaps) < 0)
220 die("Failed to create kernel maps.");
221 }
222
223 int cmd_probe(int argc, const char **argv, const char *prefix __used)
224 {
225 int i, ret;
226 #ifndef NO_LIBDWARF
227 int fd;
228 #endif
229 struct probe_point *pp;
230
231 argc = parse_options(argc, argv, options, probe_usage,
232 PARSE_OPT_STOP_AT_NON_OPTION);
233 if (argc > 0) {
234 if (strcmp(argv[0], "-") == 0) {
235 pr_warning(" Error: '-' is not supported.\n");
236 usage_with_options(probe_usage, options);
237 }
238 parse_probe_event_argv(argc, argv);
239 }
240
241 if ((!session.nr_probe && !session.dellist && !session.list_events &&
242 !session.show_lines))
243 usage_with_options(probe_usage, options);
244
245 if (debugfs_valid_mountpoint(debugfs_path) < 0)
246 die("Failed to find debugfs path.");
247
248 if (session.list_events) {
249 if (session.nr_probe != 0 || session.dellist) {
250 pr_warning(" Error: Don't use --list with"
251 " --add/--del.\n");
252 usage_with_options(probe_usage, options);
253 }
254 if (session.show_lines) {
255 pr_warning(" Error: Don't use --list with --line.\n");
256 usage_with_options(probe_usage, options);
257 }
258 show_perf_probe_events();
259 return 0;
260 }
261
262 #ifndef NO_LIBDWARF
263 if (session.show_lines) {
264 if (session.nr_probe != 0 || session.dellist) {
265 pr_warning(" Error: Don't use --line with"
266 " --add/--del.\n");
267 usage_with_options(probe_usage, options);
268 }
269 init_vmlinux();
270 fd = open_vmlinux();
271 if (fd < 0)
272 die("Could not open debuginfo file.");
273 ret = find_line_range(fd, &session.line_range);
274 if (ret <= 0)
275 die("Source line is not found.\n");
276 close(fd);
277 show_line_range(&session.line_range);
278 return 0;
279 }
280 #endif
281
282 if (session.dellist) {
283 del_trace_kprobe_events(session.dellist);
284 strlist__delete(session.dellist);
285 if (session.nr_probe == 0)
286 return 0;
287 }
288
289 /* Add probes */
290 init_vmlinux();
291
292 if (session.need_dwarf)
293 #ifdef NO_LIBDWARF
294 die("Debuginfo-analysis is not supported");
295 #else /* !NO_LIBDWARF */
296 pr_debug("Some probes require debuginfo.\n");
297
298 fd = open_vmlinux();
299 if (fd < 0) {
300 if (session.need_dwarf)
301 die("Could not open debuginfo file.");
302
303 pr_debug("Could not open vmlinux/module file."
304 " Try to use symbols.\n");
305 goto end_dwarf;
306 }
307
308 /* Searching probe points */
309 for (i = 0; i < session.nr_probe; i++) {
310 pp = &session.probes[i];
311 if (pp->found)
312 continue;
313
314 lseek(fd, SEEK_SET, 0);
315 ret = find_probepoint(fd, pp);
316 if (ret > 0)
317 continue;
318 if (ret == 0) { /* No error but failed to find probe point. */
319 synthesize_perf_probe_point(pp);
320 die("Probe point '%s' not found. - probe not added.",
321 pp->probes[0]);
322 }
323 /* Error path */
324 if (session.need_dwarf) {
325 if (ret == -ENOENT)
326 pr_warning("No dwarf info found in the vmlinux - please rebuild with CONFIG_DEBUG_INFO=y.\n");
327 die("Could not analyze debuginfo.");
328 }
329 pr_debug("An error occurred in debuginfo analysis."
330 " Try to use symbols.\n");
331 break;
332 }
333 close(fd);
334
335 end_dwarf:
336 #endif /* !NO_LIBDWARF */
337
338 /* Synthesize probes without dwarf */
339 for (i = 0; i < session.nr_probe; i++) {
340 pp = &session.probes[i];
341 if (pp->found) /* This probe is already found. */
342 continue;
343
344 evaluate_probe_point(pp);
345 ret = synthesize_trace_kprobe_event(pp);
346 if (ret == -E2BIG)
347 die("probe point definition becomes too long.");
348 else if (ret < 0)
349 die("Failed to synthesize a probe point.");
350 }
351
352 /* Settng up probe points */
353 add_trace_kprobe_events(session.probes, session.nr_probe,
354 session.force_add);
355 return 0;
356 }
357
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