aboutsummaryrefslogtreecommitdiff
path: root/tools/perf/builtin-probe.c
blob: b5d15cf254710e62c606e38731775c22077fc942 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
/*
 * builtin-probe.c
 *
 * Builtin probe command: Set up probe events by C expression
 *
 * Written by Masami Hiramatsu <mhiramat@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */
#define _GNU_SOURCE
#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

#undef _GNU_SOURCE
#include "perf.h"
#include "builtin.h"
#include "util/util.h"
#include "util/event.h"
#include "util/debug.h"
#include "util/parse-options.h"
#include "util/parse-events.h"	/* For debugfs_path */
#include "util/probe-finder.h"
#include "util/probe-event.h"

/* Default vmlinux search paths */
#define NR_SEARCH_PATH 3
const char *default_search_path[NR_SEARCH_PATH] = {
"/lib/modules/%s/build/vmlinux",		/* Custom build kernel */
"/usr/lib/debug/lib/modules/%s/vmlinux",	/* Red Hat debuginfo */
"/boot/vmlinux-debug-%s",			/* Ubuntu */
};

#define MAX_PATH_LEN 256
#define MAX_PROBES 128

/* Session management structure */
static struct {
	char *vmlinux;
	char *release;
	int need_dwarf;
	int nr_probe;
	struct probe_point probes[MAX_PROBES];
} session;

static bool listing;

/* Parse an event definition. Note that any error must die. */
static void parse_probe_event(const char *str)
{
	struct probe_point *pp = &session.probes[session.nr_probe];

	pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
	if (++session.nr_probe == MAX_PROBES)
		die("Too many probes (> %d) are specified.", MAX_PROBES);

	/* Parse perf-probe event into probe_point */
	session.need_dwarf = parse_perf_probe_event(str, pp);

	pr_debug("%d arguments\n", pp->nr_args);
}

static int opt_add_probe_event(const struct option *opt __used,
			      const char *str, int unset __used)
{
	if (str)
		parse_probe_event(str);
	return 0;
}

#ifndef NO_LIBDWARF
static int open_default_vmlinux(void)
{
	struct utsname uts;
	char fname[MAX_PATH_LEN];
	int fd, ret, i;

	ret = uname(&uts);
	if (ret) {
		pr_debug("uname() failed.\n");
		return -errno;
	}
	session.release = uts.release;
	for (i = 0; i < NR_SEARCH_PATH; i++) {
		ret = snprintf(fname, MAX_PATH_LEN,
			       default_search_path[i], session.release);
		if (ret >= MAX_PATH_LEN || ret < 0) {
			pr_debug("Filename(%d,%s) is too long.\n", i,
				uts.release);
			errno = E2BIG;
			return -E2BIG;
		}
		pr_debug("try to open %s\n", fname);
		fd = open(fname, O_RDONLY);
		if (fd >= 0)
			break;
	}
	return fd;
}
#endif

static const char * const probe_usage[] = {
	"perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
	"perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
	"perf probe --list",
	NULL
};

static const struct option options[] = {
	OPT_BOOLEAN('v', "verbose", &verbose,
		    "be more verbose (show parsed arguments, etc)"),
#ifndef NO_LIBDWARF
	OPT_STRING('k', "vmlinux", &session.vmlinux, "file",
		"vmlinux/module pathname"),
#endif
	OPT_BOOLEAN('l', "list", &listing, "list up current probes"),
	OPT_CALLBACK('a', "add", NULL,
#ifdef NO_LIBDWARF
		"FUNC[+OFFS|%return] [ARG ...]",
#else
		"FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",
#endif
		"probe point definition, where\n"
		"\t\tGRP:\tGroup name (optional)\n"
		"\t\tNAME:\tEvent name\n"
		"\t\tFUNC:\tFunction name\n"
		"\t\tOFFS:\tOffset from function entry (in byte)\n"
		"\t\t%return:\tPut the probe at function return\n"
#ifdef NO_LIBDWARF
		"\t\tARG:\tProbe argument (only \n"
#else
		"\t\tSRC:\tSource code path\n"
		"\t\tRLN:\tRelative line number from function entry.\n"
		"\t\tALN:\tAbsolute line number in file.\n"
		"\t\tARG:\tProbe argument (local variable name or\n"
#endif
		"\t\t\tkprobe-tracer argument format.)\n",
		opt_add_probe_event),
	OPT_END()
};

int cmd_probe(int argc, const char **argv, const char *prefix __used)
{
	int i, j, fd, ret;
	struct probe_point *pp;

	argc = parse_options(argc, argv, options, probe_usage,
			     PARSE_OPT_STOP_AT_NON_OPTION);
	for (i = 0; i < argc; i++)
		parse_probe_event(argv[i]);

	if ((session.nr_probe == 0 && !listing) ||
	    (session.nr_probe != 0 && listing))
		usage_with_options(probe_usage, options);

	if (listing) {
		show_perf_probe_events();
		return 0;
	}

	if (session.need_dwarf)
#ifdef NO_LIBDWARF
		die("Debuginfo-analysis is not supported");
#else	/* !NO_LIBDWARF */
		pr_debug("Some probes require debuginfo.\n");

	if (session.vmlinux)
		fd = open(session.vmlinux, O_RDONLY);
	else
		fd = open_default_vmlinux();
	if (fd < 0) {
		if (session.need_dwarf)
			die("Could not open vmlinux/module file.");

		pr_warning("Could not open vmlinux/module file."
			   " Try to use symbols.\n");
		goto end_dwarf;
	}

	/* Searching probe points */
	for (j = 0; j < session.nr_probe; j++) {
		pp = &session.probes[j];
		if (pp->found)
			continue;

		lseek(fd, SEEK_SET, 0);
		ret = find_probepoint(fd, pp);
		if (ret < 0) {
			if (session.need_dwarf)
				die("Could not analyze debuginfo.");

			pr_warning("An error occurred in debuginfo analysis. Try to use symbols.\n");
			break;
		}
		if (ret == 0)	/* No error but failed to find probe point. */
			die("No probe point found.");
	}
	close(fd);

end_dwarf:
#endif /* !NO_LIBDWARF */

	/* Synthesize probes without dwarf */
	for (j = 0; j < session.nr_probe; j++) {
		pp = &session.probes[j];
		if (pp->found)	/* This probe is already found. */
			continue;

		ret = synthesize_trace_kprobe_event(pp);
		if (ret == -E2BIG)
			die("probe point definition becomes too long.");
		else if (ret < 0)
			die("Failed to synthesize a probe point.");
	}

	/* Settng up probe points */
	add_trace_kprobe_events(session.probes, session.nr_probe);
	return 0;
}