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9#include "builtin.h"
10#include "perf.h"
11
12#include <errno.h>
13#include <unistd.h>
14#include <signal.h>
15#include <fcntl.h>
16#include <poll.h>
17
18#include "debug.h"
19#include <subcmd/parse-options.h>
20#include <api/fs/tracing_path.h>
21#include "evlist.h"
22#include "target.h"
23#include "cpumap.h"
24#include "thread_map.h"
25#include "util/config.h"
26
27
28#define DEFAULT_TRACER "function_graph"
29
30struct perf_ftrace {
31 struct perf_evlist *evlist;
32 struct target target;
33 const char *tracer;
34 struct list_head filters;
35 struct list_head notrace;
36 struct list_head graph_funcs;
37 struct list_head nograph_funcs;
38 int graph_depth;
39};
40
41struct filter_entry {
42 struct list_head list;
43 char name[];
44};
45
46static bool done;
47
48static void sig_handler(int sig __maybe_unused)
49{
50 done = true;
51}
52
53
54
55
56
57
58
59
60static void ftrace__workload_exec_failed_signal(int signo __maybe_unused,
61 siginfo_t *info __maybe_unused,
62 void *ucontext __maybe_unused)
63{
64
65 done = true;
66}
67
68static int __write_tracing_file(const char *name, const char *val, bool append)
69{
70 char *file;
71 int fd, ret = -1;
72 ssize_t size = strlen(val);
73 int flags = O_WRONLY;
74 char errbuf[512];
75
76 file = get_tracing_file(name);
77 if (!file) {
78 pr_debug("cannot get tracing file: %s\n", name);
79 return -1;
80 }
81
82 if (append)
83 flags |= O_APPEND;
84 else
85 flags |= O_TRUNC;
86
87 fd = open(file, flags);
88 if (fd < 0) {
89 pr_debug("cannot open tracing file: %s: %s\n",
90 name, str_error_r(errno, errbuf, sizeof(errbuf)));
91 goto out;
92 }
93
94 if (write(fd, val, size) == size)
95 ret = 0;
96 else
97 pr_debug("write '%s' to tracing/%s failed: %s\n",
98 val, name, str_error_r(errno, errbuf, sizeof(errbuf)));
99
100 close(fd);
101out:
102 put_tracing_file(file);
103 return ret;
104}
105
106static int write_tracing_file(const char *name, const char *val)
107{
108 return __write_tracing_file(name, val, false);
109}
110
111static int append_tracing_file(const char *name, const char *val)
112{
113 return __write_tracing_file(name, val, true);
114}
115
116static int reset_tracing_cpu(void);
117static void reset_tracing_filters(void);
118
119static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
120{
121 if (write_tracing_file("tracing_on", "0") < 0)
122 return -1;
123
124 if (write_tracing_file("current_tracer", "nop") < 0)
125 return -1;
126
127 if (write_tracing_file("set_ftrace_pid", " ") < 0)
128 return -1;
129
130 if (reset_tracing_cpu() < 0)
131 return -1;
132
133 if (write_tracing_file("max_graph_depth", "0") < 0)
134 return -1;
135
136 reset_tracing_filters();
137 return 0;
138}
139
140static int set_tracing_pid(struct perf_ftrace *ftrace)
141{
142 int i;
143 char buf[16];
144
145 if (target__has_cpu(&ftrace->target))
146 return 0;
147
148 for (i = 0; i < thread_map__nr(ftrace->evlist->threads); i++) {
149 scnprintf(buf, sizeof(buf), "%d",
150 ftrace->evlist->threads->map[i]);
151 if (append_tracing_file("set_ftrace_pid", buf) < 0)
152 return -1;
153 }
154 return 0;
155}
156
157static int set_tracing_cpumask(struct cpu_map *cpumap)
158{
159 char *cpumask;
160 size_t mask_size;
161 int ret;
162 int last_cpu;
163
164 last_cpu = cpu_map__cpu(cpumap, cpumap->nr - 1);
165 mask_size = (last_cpu + 3) / 4 + 1;
166 mask_size += last_cpu / 32;
167
168 cpumask = malloc(mask_size);
169 if (cpumask == NULL) {
170 pr_debug("failed to allocate cpu mask\n");
171 return -1;
172 }
173
174 cpu_map__snprint_mask(cpumap, cpumask, mask_size);
175
176 ret = write_tracing_file("tracing_cpumask", cpumask);
177
178 free(cpumask);
179 return ret;
180}
181
182static int set_tracing_cpu(struct perf_ftrace *ftrace)
183{
184 struct cpu_map *cpumap = ftrace->evlist->cpus;
185
186 if (!target__has_cpu(&ftrace->target))
187 return 0;
188
189 return set_tracing_cpumask(cpumap);
190}
191
192static int reset_tracing_cpu(void)
193{
194 struct cpu_map *cpumap = cpu_map__new(NULL);
195 int ret;
196
197 ret = set_tracing_cpumask(cpumap);
198 cpu_map__put(cpumap);
199 return ret;
200}
201
202static int __set_tracing_filter(const char *filter_file, struct list_head *funcs)
203{
204 struct filter_entry *pos;
205
206 list_for_each_entry(pos, funcs, list) {
207 if (append_tracing_file(filter_file, pos->name) < 0)
208 return -1;
209 }
210
211 return 0;
212}
213
214static int set_tracing_filters(struct perf_ftrace *ftrace)
215{
216 int ret;
217
218 ret = __set_tracing_filter("set_ftrace_filter", &ftrace->filters);
219 if (ret < 0)
220 return ret;
221
222 ret = __set_tracing_filter("set_ftrace_notrace", &ftrace->notrace);
223 if (ret < 0)
224 return ret;
225
226 ret = __set_tracing_filter("set_graph_function", &ftrace->graph_funcs);
227 if (ret < 0)
228 return ret;
229
230
231 __set_tracing_filter("set_graph_notrace", &ftrace->nograph_funcs);
232
233 return ret;
234}
235
236static void reset_tracing_filters(void)
237{
238 write_tracing_file("set_ftrace_filter", " ");
239 write_tracing_file("set_ftrace_notrace", " ");
240 write_tracing_file("set_graph_function", " ");
241 write_tracing_file("set_graph_notrace", " ");
242}
243
244static int set_tracing_depth(struct perf_ftrace *ftrace)
245{
246 char buf[16];
247
248 if (ftrace->graph_depth == 0)
249 return 0;
250
251 if (ftrace->graph_depth < 0) {
252 pr_err("invalid graph depth: %d\n", ftrace->graph_depth);
253 return -1;
254 }
255
256 snprintf(buf, sizeof(buf), "%d", ftrace->graph_depth);
257
258 if (write_tracing_file("max_graph_depth", buf) < 0)
259 return -1;
260
261 return 0;
262}
263
264static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
265{
266 char *trace_file;
267 int trace_fd;
268 char buf[4096];
269 struct pollfd pollfd = {
270 .events = POLLIN,
271 };
272
273 if (geteuid() != 0) {
274 pr_err("ftrace only works for root!\n");
275 return -1;
276 }
277
278 signal(SIGINT, sig_handler);
279 signal(SIGUSR1, sig_handler);
280 signal(SIGCHLD, sig_handler);
281 signal(SIGPIPE, sig_handler);
282
283 if (reset_tracing_files(ftrace) < 0)
284 goto out;
285
286
287 if (write_tracing_file("trace", "0") < 0)
288 goto out;
289
290 if (argc && perf_evlist__prepare_workload(ftrace->evlist,
291 &ftrace->target, argv, false,
292 ftrace__workload_exec_failed_signal) < 0) {
293 goto out;
294 }
295
296 if (set_tracing_pid(ftrace) < 0) {
297 pr_err("failed to set ftrace pid\n");
298 goto out_reset;
299 }
300
301 if (set_tracing_cpu(ftrace) < 0) {
302 pr_err("failed to set tracing cpumask\n");
303 goto out_reset;
304 }
305
306 if (set_tracing_filters(ftrace) < 0) {
307 pr_err("failed to set tracing filters\n");
308 goto out_reset;
309 }
310
311 if (set_tracing_depth(ftrace) < 0) {
312 pr_err("failed to set graph depth\n");
313 goto out_reset;
314 }
315
316 if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
317 pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
318 goto out_reset;
319 }
320
321 setup_pager();
322
323 trace_file = get_tracing_file("trace_pipe");
324 if (!trace_file) {
325 pr_err("failed to open trace_pipe\n");
326 goto out_reset;
327 }
328
329 trace_fd = open(trace_file, O_RDONLY);
330
331 put_tracing_file(trace_file);
332
333 if (trace_fd < 0) {
334 pr_err("failed to open trace_pipe\n");
335 goto out_reset;
336 }
337
338 fcntl(trace_fd, F_SETFL, O_NONBLOCK);
339 pollfd.fd = trace_fd;
340
341 if (write_tracing_file("tracing_on", "1") < 0) {
342 pr_err("can't enable tracing\n");
343 goto out_close_fd;
344 }
345
346 perf_evlist__start_workload(ftrace->evlist);
347
348 while (!done) {
349 if (poll(&pollfd, 1, -1) < 0)
350 break;
351
352 if (pollfd.revents & POLLIN) {
353 int n = read(trace_fd, buf, sizeof(buf));
354 if (n < 0)
355 break;
356 if (fwrite(buf, n, 1, stdout) != 1)
357 break;
358 }
359 }
360
361 write_tracing_file("tracing_on", "0");
362
363
364 while (true) {
365 int n = read(trace_fd, buf, sizeof(buf));
366 if (n <= 0)
367 break;
368 if (fwrite(buf, n, 1, stdout) != 1)
369 break;
370 }
371
372out_close_fd:
373 close(trace_fd);
374out_reset:
375 reset_tracing_files(ftrace);
376out:
377 return done ? 0 : -1;
378}
379
380static int perf_ftrace_config(const char *var, const char *value, void *cb)
381{
382 struct perf_ftrace *ftrace = cb;
383
384 if (prefixcmp(var, "ftrace."))
385 return 0;
386
387 if (strcmp(var, "ftrace.tracer"))
388 return -1;
389
390 if (!strcmp(value, "function_graph") ||
391 !strcmp(value, "function")) {
392 ftrace->tracer = value;
393 return 0;
394 }
395
396 pr_err("Please select \"function_graph\" (default) or \"function\"\n");
397 return -1;
398}
399
400static int parse_filter_func(const struct option *opt, const char *str,
401 int unset __maybe_unused)
402{
403 struct list_head *head = opt->value;
404 struct filter_entry *entry;
405
406 entry = malloc(sizeof(*entry) + strlen(str) + 1);
407 if (entry == NULL)
408 return -ENOMEM;
409
410 strcpy(entry->name, str);
411 list_add_tail(&entry->list, head);
412
413 return 0;
414}
415
416static void delete_filter_func(struct list_head *head)
417{
418 struct filter_entry *pos, *tmp;
419
420 list_for_each_entry_safe(pos, tmp, head, list) {
421 list_del(&pos->list);
422 free(pos);
423 }
424}
425
426int cmd_ftrace(int argc, const char **argv)
427{
428 int ret;
429 struct perf_ftrace ftrace = {
430 .tracer = DEFAULT_TRACER,
431 .target = { .uid = UINT_MAX, },
432 };
433 const char * const ftrace_usage[] = {
434 "perf ftrace [<options>] [<command>]",
435 "perf ftrace [<options>] -- <command> [<options>]",
436 NULL
437 };
438 const struct option ftrace_options[] = {
439 OPT_STRING('t', "tracer", &ftrace.tracer, "tracer",
440 "tracer to use: function_graph(default) or function"),
441 OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
442 "trace on existing process id"),
443 OPT_INCR('v', "verbose", &verbose,
444 "be more verbose"),
445 OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,
446 "system-wide collection from all CPUs"),
447 OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",
448 "list of cpus to monitor"),
449 OPT_CALLBACK('T', "trace-funcs", &ftrace.filters, "func",
450 "trace given functions only", parse_filter_func),
451 OPT_CALLBACK('N', "notrace-funcs", &ftrace.notrace, "func",
452 "do not trace given functions", parse_filter_func),
453 OPT_CALLBACK('G', "graph-funcs", &ftrace.graph_funcs, "func",
454 "Set graph filter on given functions", parse_filter_func),
455 OPT_CALLBACK('g', "nograph-funcs", &ftrace.nograph_funcs, "func",
456 "Set nograph filter on given functions", parse_filter_func),
457 OPT_INTEGER('D', "graph-depth", &ftrace.graph_depth,
458 "Max depth for function graph tracer"),
459 OPT_END()
460 };
461
462 INIT_LIST_HEAD(&ftrace.filters);
463 INIT_LIST_HEAD(&ftrace.notrace);
464 INIT_LIST_HEAD(&ftrace.graph_funcs);
465 INIT_LIST_HEAD(&ftrace.nograph_funcs);
466
467 ret = perf_config(perf_ftrace_config, &ftrace);
468 if (ret < 0)
469 return -1;
470
471 argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
472 PARSE_OPT_STOP_AT_NON_OPTION);
473 if (!argc && target__none(&ftrace.target))
474 usage_with_options(ftrace_usage, ftrace_options);
475
476 ret = target__validate(&ftrace.target);
477 if (ret) {
478 char errbuf[512];
479
480 target__strerror(&ftrace.target, ret, errbuf, 512);
481 pr_err("%s\n", errbuf);
482 goto out_delete_filters;
483 }
484
485 ftrace.evlist = perf_evlist__new();
486 if (ftrace.evlist == NULL) {
487 ret = -ENOMEM;
488 goto out_delete_filters;
489 }
490
491 ret = perf_evlist__create_maps(ftrace.evlist, &ftrace.target);
492 if (ret < 0)
493 goto out_delete_evlist;
494
495 ret = __cmd_ftrace(&ftrace, argc, argv);
496
497out_delete_evlist:
498 perf_evlist__delete(ftrace.evlist);
499
500out_delete_filters:
501 delete_filter_func(&ftrace.filters);
502 delete_filter_func(&ftrace.notrace);
503 delete_filter_func(&ftrace.graph_funcs);
504 delete_filter_func(&ftrace.nograph_funcs);
505
506 return ret;
507}
508
