Root/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
51/* Session management structure */
52static struct {
53    bool need_dwarf;
54    bool list_events;
55    bool force_add;
56    bool show_lines;
57    int nr_probe;
58    struct probe_point probes[MAX_PROBES];
59    struct strlist *dellist;
60    struct map_groups kmap_groups;
61    struct map *kmaps[MAP__NR_TYPES];
62    struct line_range line_range;
63} session;
64
65
66/* Parse an event definition. Note that any error must die. */
67static 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
81static 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
100static 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
108static 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 */
120static void evaluate_probe_point(struct probe_point *pp)
121{
122    struct symbol *sym;
123    sym = map__find_symbol_by_name(session.kmaps[MAP__FUNCTION],
124                       pp->function, NULL);
125    if (!sym)
126        die("Kernel symbol \'%s\' not found - probe not added.",
127            pp->function);
128}
129
130#ifndef NO_DWARF_SUPPORT
131static int open_vmlinux(void)
132{
133    if (map__load(session.kmaps[MAP__FUNCTION], NULL) < 0) {
134        pr_debug("Failed to load kernel map.\n");
135        return -EINVAL;
136    }
137    pr_debug("Try to open %s\n",
138         session.kmaps[MAP__FUNCTION]->dso->long_name);
139    return open(session.kmaps[MAP__FUNCTION]->dso->long_name, O_RDONLY);
140}
141
142static int opt_show_lines(const struct option *opt __used,
143              const char *str, int unset __used)
144{
145    if (str)
146        parse_line_range_desc(str, &session.line_range);
147    INIT_LIST_HEAD(&session.line_range.line_list);
148    session.show_lines = true;
149    return 0;
150}
151#endif
152
153static const char * const probe_usage[] = {
154    "perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
155    "perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
156    "perf probe [<options>] --del '[GROUP:]EVENT' ...",
157    "perf probe --list",
158#ifndef NO_DWARF_SUPPORT
159    "perf probe --line 'LINEDESC'",
160#endif
161    NULL
162};
163
164static const struct option options[] = {
165    OPT_BOOLEAN('v', "verbose", &verbose,
166            "be more verbose (show parsed arguments, etc)"),
167#ifndef NO_DWARF_SUPPORT
168    OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
169           "file", "vmlinux pathname"),
170#endif
171    OPT_BOOLEAN('l', "list", &session.list_events,
172            "list up current probe events"),
173    OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.",
174        opt_del_probe_event),
175    OPT_CALLBACK('a', "add", NULL,
176#ifdef NO_DWARF_SUPPORT
177        "[EVENT=]FUNC[+OFF|%return] [ARG ...]",
178#else
179        "[EVENT=]FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT"
180        " [ARG ...]",
181#endif
182        "probe point definition, where\n"
183        "\t\tGROUP:\tGroup name (optional)\n"
184        "\t\tEVENT:\tEvent name\n"
185        "\t\tFUNC:\tFunction name\n"
186        "\t\tOFF:\tOffset from function entry (in byte)\n"
187        "\t\t%return:\tPut the probe at function return\n"
188#ifdef NO_DWARF_SUPPORT
189        "\t\tARG:\tProbe argument (only \n"
190#else
191        "\t\tSRC:\tSource code path\n"
192        "\t\tRL:\tRelative line number from function entry.\n"
193        "\t\tAL:\tAbsolute line number in file.\n"
194        "\t\tPT:\tLazy expression of line code.\n"
195        "\t\tARG:\tProbe argument (local variable name or\n"
196#endif
197        "\t\t\tkprobe-tracer argument format.)\n",
198        opt_add_probe_event),
199    OPT_BOOLEAN('f', "force", &session.force_add, "forcibly add events"
200            " with existing name"),
201#ifndef NO_DWARF_SUPPORT
202    OPT_CALLBACK('L', "line", NULL,
203             "FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]",
204             "Show source code lines.", opt_show_lines),
205#endif
206    OPT_END()
207};
208
209/* Initialize symbol maps for vmlinux */
210static void init_vmlinux(void)
211{
212    symbol_conf.sort_by_name = true;
213    if (symbol_conf.vmlinux_name == NULL)
214        symbol_conf.try_vmlinux_path = true;
215    else
216        pr_debug("Use vmlinux: %s\n", symbol_conf.vmlinux_name);
217    if (symbol__init() < 0)
218        die("Failed to init symbol map.");
219
220    map_groups__init(&session.kmap_groups);
221    if (map_groups__create_kernel_maps(&session.kmap_groups,
222                       session.kmaps) < 0)
223        die("Failed to create kernel maps.");
224}
225
226int cmd_probe(int argc, const char **argv, const char *prefix __used)
227{
228    int i, ret;
229#ifndef NO_DWARF_SUPPORT
230    int fd;
231#endif
232    struct probe_point *pp;
233
234    argc = parse_options(argc, argv, options, probe_usage,
235                 PARSE_OPT_STOP_AT_NON_OPTION);
236    if (argc > 0) {
237        if (strcmp(argv[0], "-") == 0) {
238            pr_warning(" Error: '-' is not supported.\n");
239            usage_with_options(probe_usage, options);
240        }
241        parse_probe_event_argv(argc, argv);
242    }
243
244    if ((!session.nr_probe && !session.dellist && !session.list_events &&
245         !session.show_lines))
246        usage_with_options(probe_usage, options);
247
248    if (debugfs_valid_mountpoint(debugfs_path) < 0)
249        die("Failed to find debugfs path.");
250
251    if (session.list_events) {
252        if (session.nr_probe != 0 || session.dellist) {
253            pr_warning(" Error: Don't use --list with"
254                   " --add/--del.\n");
255            usage_with_options(probe_usage, options);
256        }
257        if (session.show_lines) {
258            pr_warning(" Error: Don't use --list with --line.\n");
259            usage_with_options(probe_usage, options);
260        }
261        show_perf_probe_events();
262        return 0;
263    }
264
265#ifndef NO_DWARF_SUPPORT
266    if (session.show_lines) {
267        if (session.nr_probe != 0 || session.dellist) {
268            pr_warning(" Error: Don't use --line with"
269                   " --add/--del.\n");
270            usage_with_options(probe_usage, options);
271        }
272        init_vmlinux();
273        fd = open_vmlinux();
274        if (fd < 0)
275            die("Could not open debuginfo file.");
276        ret = find_line_range(fd, &session.line_range);
277        if (ret <= 0)
278            die("Source line is not found.\n");
279        close(fd);
280        show_line_range(&session.line_range);
281        return 0;
282    }
283#endif
284
285    if (session.dellist) {
286        del_trace_kprobe_events(session.dellist);
287        strlist__delete(session.dellist);
288        if (session.nr_probe == 0)
289            return 0;
290    }
291
292    /* Add probes */
293    init_vmlinux();
294
295    if (session.need_dwarf)
296#ifdef NO_DWARF_SUPPORT
297        die("Debuginfo-analysis is not supported");
298#else /* !NO_DWARF_SUPPORT */
299        pr_debug("Some probes require debuginfo.\n");
300
301    fd = open_vmlinux();
302    if (fd < 0) {
303        if (session.need_dwarf)
304            die("Could not open debuginfo file.");
305
306        pr_debug("Could not open vmlinux/module file."
307             " Try to use symbols.\n");
308        goto end_dwarf;
309    }
310
311    /* Searching probe points */
312    for (i = 0; i < session.nr_probe; i++) {
313        pp = &session.probes[i];
314        if (pp->found)
315            continue;
316
317        lseek(fd, SEEK_SET, 0);
318        ret = find_probe_point(fd, pp);
319        if (ret > 0)
320            continue;
321        if (ret == 0) { /* No error but failed to find probe point. */
322            synthesize_perf_probe_point(pp);
323            die("Probe point '%s' not found. - probe not added.",
324                pp->probes[0]);
325        }
326        /* Error path */
327        if (session.need_dwarf) {
328            if (ret == -ENOENT)
329                pr_warning("No dwarf info found in the vmlinux - please rebuild with CONFIG_DEBUG_INFO=y.\n");
330            die("Could not analyze debuginfo.");
331        }
332        pr_debug("An error occurred in debuginfo analysis."
333             " Try to use symbols.\n");
334        break;
335    }
336    close(fd);
337
338end_dwarf:
339#endif /* !NO_DWARF_SUPPORT */
340
341    /* Synthesize probes without dwarf */
342    for (i = 0; i < session.nr_probe; i++) {
343        pp = &session.probes[i];
344        if (pp->found) /* This probe is already found. */
345            continue;
346
347        evaluate_probe_point(pp);
348        ret = synthesize_trace_kprobe_event(pp);
349        if (ret == -E2BIG)
350            die("probe point definition becomes too long.");
351        else if (ret < 0)
352            die("Failed to synthesize a probe point.");
353    }
354
355    /* Settng up probe points */
356    add_trace_kprobe_events(session.probes, session.nr_probe,
357                session.force_add);
358    return 0;
359}
360
361

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