perf session: Keep pointers to the vmlinux maps
[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/debugfs.h"
42 #include "util/symbol.h"
43 #include "util/thread.h"
44 #include "util/session.h"
45 #include "util/parse-options.h"
46 #include "util/parse-events.h"  /* For debugfs_path */
47 #include "util/probe-finder.h"
48 #include "util/probe-event.h"
49
50 #define MAX_PATH_LEN 256
51 #define MAX_PROBES 128
52
53 /* Session management structure */
54 static struct {
55         bool need_dwarf;
56         bool list_events;
57         bool force_add;
58         int nr_probe;
59         struct probe_point probes[MAX_PROBES];
60         struct strlist *dellist;
61         struct perf_session *psession;
62         struct map *kmap;
63 } session;
64
65
66 /* Parse an event definition. Note that any error must die. */
67 static void parse_probe_event(const char *str)
68 {
69         struct probe_point *pp = &session.probes[session.nr_probe];
70
71         pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
72         if (++session.nr_probe == MAX_PROBES)
73                 die("Too many probes (> %d) are specified.", MAX_PROBES);
74
75         /* Parse perf-probe event into probe_point */
76         parse_perf_probe_event(str, pp, &session.need_dwarf);
77
78         pr_debug("%d arguments\n", pp->nr_args);
79 }
80
81 static void parse_probe_event_argv(int argc, const char **argv)
82 {
83         int i, len;
84         char *buf;
85
86         /* Bind up rest arguments */
87         len = 0;
88         for (i = 0; i < argc; i++)
89                 len += strlen(argv[i]) + 1;
90         buf = zalloc(len + 1);
91         if (!buf)
92                 die("Failed to allocate memory for binding arguments.");
93         len = 0;
94         for (i = 0; i < argc; i++)
95                 len += sprintf(&buf[len], "%s ", argv[i]);
96         parse_probe_event(buf);
97         free(buf);
98 }
99
100 static int opt_add_probe_event(const struct option *opt __used,
101                               const char *str, int unset __used)
102 {
103         if (str)
104                 parse_probe_event(str);
105         return 0;
106 }
107
108 static int opt_del_probe_event(const struct option *opt __used,
109                                const char *str, int unset __used)
110 {
111         if (str) {
112                 if (!session.dellist)
113                         session.dellist = strlist__new(true, NULL);
114                 strlist__add(session.dellist, str);
115         }
116         return 0;
117 }
118
119 /* Currently just checking function name from symbol map */
120 static void evaluate_probe_point(struct probe_point *pp)
121 {
122         struct symbol *sym;
123         sym = map__find_symbol_by_name(session.kmap, pp->function,
124                                        session.psession, NULL);
125         if (!sym)
126                 die("Kernel symbol \'%s\' not found - probe not added.",
127                     pp->function);
128 }
129
130 #ifndef NO_LIBDWARF
131 static int open_vmlinux(void)
132 {
133         if (map__load(session.kmap, session.psession, NULL) < 0) {
134                 pr_debug("Failed to load kernel map.\n");
135                 return -EINVAL;
136         }
137         pr_debug("Try to open %s\n", session.kmap->dso->long_name);
138         return open(session.kmap->dso->long_name, O_RDONLY);
139 }
140 #endif
141
142 static const char * const probe_usage[] = {
143         "perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
144         "perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
145         "perf probe [<options>] --del '[GROUP:]EVENT' ...",
146         "perf probe --list",
147         NULL
148 };
149
150 static const struct option options[] = {
151         OPT_BOOLEAN('v', "verbose", &verbose,
152                     "be more verbose (show parsed arguments, etc)"),
153 #ifndef NO_LIBDWARF
154         OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
155                    "file", "vmlinux pathname"),
156 #endif
157         OPT_BOOLEAN('l', "list", &session.list_events,
158                     "list up current probe events"),
159         OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.",
160                 opt_del_probe_event),
161         OPT_CALLBACK('a', "add", NULL,
162 #ifdef NO_LIBDWARF
163                 "[EVENT=]FUNC[+OFFS|%return] [ARG ...]",
164 #else
165                 "[EVENT=]FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",
166 #endif
167                 "probe point definition, where\n"
168                 "\t\tGROUP:\tGroup name (optional)\n"
169                 "\t\tEVENT:\tEvent name\n"
170                 "\t\tFUNC:\tFunction name\n"
171                 "\t\tOFFS:\tOffset from function entry (in byte)\n"
172                 "\t\t%return:\tPut the probe at function return\n"
173 #ifdef NO_LIBDWARF
174                 "\t\tARG:\tProbe argument (only \n"
175 #else
176                 "\t\tSRC:\tSource code path\n"
177                 "\t\tRLN:\tRelative line number from function entry.\n"
178                 "\t\tALN:\tAbsolute line number in file.\n"
179                 "\t\tARG:\tProbe argument (local variable name or\n"
180 #endif
181                 "\t\t\tkprobe-tracer argument format.)\n",
182                 opt_add_probe_event),
183         OPT_BOOLEAN('f', "force", &session.force_add, "forcibly add events"
184                     " with existing name"),
185         OPT_END()
186 };
187
188 int cmd_probe(int argc, const char **argv, const char *prefix __used)
189 {
190         int i, ret;
191 #ifndef NO_LIBDWARF
192         int fd;
193 #endif
194         struct probe_point *pp;
195
196         argc = parse_options(argc, argv, options, probe_usage,
197                              PARSE_OPT_STOP_AT_NON_OPTION);
198         if (argc > 0) {
199                 if (strcmp(argv[0], "-") == 0) {
200                         pr_warning("  Error: '-' is not supported.\n");
201                         usage_with_options(probe_usage, options);
202                 }
203                 parse_probe_event_argv(argc, argv);
204         }
205
206         if ((!session.nr_probe && !session.dellist && !session.list_events))
207                 usage_with_options(probe_usage, options);
208
209         if (debugfs_valid_mountpoint(debugfs_path) < 0)
210                 die("Failed to find debugfs path.");
211
212         if (session.list_events) {
213                 if (session.nr_probe != 0 || session.dellist) {
214                         pr_warning("  Error: Don't use --list with"
215                                    " --add/--del.\n");
216                         usage_with_options(probe_usage, options);
217                 }
218                 show_perf_probe_events();
219                 return 0;
220         }
221
222         if (session.dellist) {
223                 del_trace_kprobe_events(session.dellist);
224                 strlist__delete(session.dellist);
225                 if (session.nr_probe == 0)
226                         return 0;
227         }
228
229         /* Initialize symbol maps for vmlinux */
230         symbol_conf.sort_by_name = true;
231         if (symbol_conf.vmlinux_name == NULL)
232                 symbol_conf.try_vmlinux_path = true;
233         if (symbol__init() < 0)
234                 die("Failed to init symbol map.");
235         session.psession = perf_session__new(NULL, O_WRONLY, false);
236         if (session.psession == NULL)
237                 die("Failed to init perf_session.");
238         session.kmap = session.psession->vmlinux_maps[MAP__FUNCTION];
239         if (!session.kmap)
240                 die("Could not find kernel map.\n");
241
242         if (session.need_dwarf)
243 #ifdef NO_LIBDWARF
244                 die("Debuginfo-analysis is not supported");
245 #else   /* !NO_LIBDWARF */
246                 pr_debug("Some probes require debuginfo.\n");
247
248         fd = open_vmlinux();
249         if (fd < 0) {
250                 if (session.need_dwarf)
251                         die("Could not open debuginfo file.");
252
253                 pr_debug("Could not open vmlinux/module file."
254                          " Try to use symbols.\n");
255                 goto end_dwarf;
256         }
257
258         /* Searching probe points */
259         for (i = 0; i < session.nr_probe; i++) {
260                 pp = &session.probes[i];
261                 if (pp->found)
262                         continue;
263
264                 lseek(fd, SEEK_SET, 0);
265                 ret = find_probepoint(fd, pp);
266                 if (ret > 0)
267                         continue;
268                 if (ret == 0) { /* No error but failed to find probe point. */
269                         synthesize_perf_probe_point(pp);
270                         die("Probe point '%s' not found. - probe not added.",
271                             pp->probes[0]);
272                 }
273                 /* Error path */
274                 if (session.need_dwarf) {
275                         if (ret == -ENOENT)
276                                 pr_warning("No dwarf info found in the vmlinux - please rebuild with CONFIG_DEBUG_INFO=y.\n");
277                         die("Could not analyze debuginfo.");
278                 }
279                 pr_debug("An error occurred in debuginfo analysis."
280                          " Try to use symbols.\n");
281                 break;
282         }
283         close(fd);
284
285 end_dwarf:
286 #endif /* !NO_LIBDWARF */
287
288         /* Synthesize probes without dwarf */
289         for (i = 0; i < session.nr_probe; i++) {
290                 pp = &session.probes[i];
291                 if (pp->found)  /* This probe is already found. */
292                         continue;
293
294                 evaluate_probe_point(pp);
295                 ret = synthesize_trace_kprobe_event(pp);
296                 if (ret == -E2BIG)
297                         die("probe point definition becomes too long.");
298                 else if (ret < 0)
299                         die("Failed to synthesize a probe point.");
300         }
301
302         /* Settng up probe points */
303         add_trace_kprobe_events(session.probes, session.nr_probe,
304                                 session.force_add);
305         return 0;
306 }
307