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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 */ |
52 | static 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. */ |
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.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 |
131 | static 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 | |
142 | static 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 | |
153 | static 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 | |
164 | static 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 */ |
210 | static 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 | |
226 | int 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 | |
338 | end_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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