xref: /linux/tools/perf/util/util.c (revision 891e8abed532423d3b918b0c445dc8919bc445b5)
1 // SPDX-License-Identifier: GPL-2.0
2 #include "util.h"
3 #include "debug.h"
4 #include "event.h"
5 #include <api/fs/fs.h>
6 #include <sys/stat.h>
7 #include <sys/utsname.h>
8 #include <dirent.h>
9 #include <fcntl.h>
10 #include <inttypes.h>
11 #include <signal.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <string.h>
15 #include <errno.h>
16 #include <limits.h>
17 #include <linux/capability.h>
18 #include <linux/kernel.h>
19 #include <linux/log2.h>
20 #include <linux/time64.h>
21 #include <linux/overflow.h>
22 #include <unistd.h>
23 #include "cap.h"
24 #include "strlist.h"
25 #include "string2.h"
26 
27 /*
28  * XXX We need to find a better place for these things...
29  */
30 
31 const char *input_name;
32 
33 bool perf_singlethreaded = true;
34 
35 void perf_set_singlethreaded(void)
36 {
37 	perf_singlethreaded = true;
38 }
39 
40 void perf_set_multithreaded(void)
41 {
42 	perf_singlethreaded = false;
43 }
44 
45 int sysctl_perf_event_max_stack = PERF_MAX_STACK_DEPTH;
46 int sysctl_perf_event_max_contexts_per_stack = PERF_MAX_CONTEXTS_PER_STACK;
47 
48 int sysctl__max_stack(void)
49 {
50 	int value;
51 
52 	if (sysctl__read_int("kernel/perf_event_max_stack", &value) == 0)
53 		sysctl_perf_event_max_stack = value;
54 
55 	if (sysctl__read_int("kernel/perf_event_max_contexts_per_stack", &value) == 0)
56 		sysctl_perf_event_max_contexts_per_stack = value;
57 
58 	return sysctl_perf_event_max_stack;
59 }
60 
61 bool sysctl__nmi_watchdog_enabled(void)
62 {
63 	static bool cached;
64 	static bool nmi_watchdog;
65 	int value;
66 
67 	if (cached)
68 		return nmi_watchdog;
69 
70 	if (sysctl__read_int("kernel/nmi_watchdog", &value) < 0)
71 		return false;
72 
73 	nmi_watchdog = (value > 0) ? true : false;
74 	cached = true;
75 
76 	return nmi_watchdog;
77 }
78 
79 bool test_attr__enabled;
80 
81 bool perf_host  = true;
82 bool perf_guest = false;
83 
84 void event_attr_init(struct perf_event_attr *attr)
85 {
86 	if (!perf_host)
87 		attr->exclude_host  = 1;
88 	if (!perf_guest)
89 		attr->exclude_guest = 1;
90 	/* to capture ABI version */
91 	attr->size = sizeof(*attr);
92 }
93 
94 int mkdir_p(char *path, mode_t mode)
95 {
96 	struct stat st;
97 	int err;
98 	char *d = path;
99 
100 	if (*d != '/')
101 		return -1;
102 
103 	if (stat(path, &st) == 0)
104 		return 0;
105 
106 	while (*++d == '/');
107 
108 	while ((d = strchr(d, '/'))) {
109 		*d = '\0';
110 		err = stat(path, &st) && mkdir(path, mode);
111 		*d++ = '/';
112 		if (err)
113 			return -1;
114 		while (*d == '/')
115 			++d;
116 	}
117 	return (stat(path, &st) && mkdir(path, mode)) ? -1 : 0;
118 }
119 
120 static bool match_pat(char *file, const char **pat)
121 {
122 	int i = 0;
123 
124 	if (!pat)
125 		return true;
126 
127 	while (pat[i]) {
128 		if (strglobmatch(file, pat[i]))
129 			return true;
130 
131 		i++;
132 	}
133 
134 	return false;
135 }
136 
137 /*
138  * The depth specify how deep the removal will go.
139  * 0       - will remove only files under the 'path' directory
140  * 1 .. x  - will dive in x-level deep under the 'path' directory
141  *
142  * If specified the pat is array of string patterns ended with NULL,
143  * which are checked upon every file/directory found. Only matching
144  * ones are removed.
145  *
146  * The function returns:
147  *    0 on success
148  *   -1 on removal failure with errno set
149  *   -2 on pattern failure
150  */
151 static int rm_rf_depth_pat(const char *path, int depth, const char **pat)
152 {
153 	DIR *dir;
154 	int ret;
155 	struct dirent *d;
156 	char namebuf[PATH_MAX];
157 	struct stat statbuf;
158 
159 	/* Do not fail if there's no file. */
160 	ret = lstat(path, &statbuf);
161 	if (ret)
162 		return 0;
163 
164 	/* Try to remove any file we get. */
165 	if (!(statbuf.st_mode & S_IFDIR))
166 		return unlink(path);
167 
168 	/* We have directory in path. */
169 	dir = opendir(path);
170 	if (dir == NULL)
171 		return -1;
172 
173 	while ((d = readdir(dir)) != NULL && !ret) {
174 
175 		if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
176 			continue;
177 
178 		if (!match_pat(d->d_name, pat)) {
179 			ret =  -2;
180 			break;
181 		}
182 
183 		scnprintf(namebuf, sizeof(namebuf), "%s/%s",
184 			  path, d->d_name);
185 
186 		/* We have to check symbolic link itself */
187 		ret = lstat(namebuf, &statbuf);
188 		if (ret < 0) {
189 			pr_debug("stat failed: %s\n", namebuf);
190 			break;
191 		}
192 
193 		if (S_ISDIR(statbuf.st_mode))
194 			ret = depth ? rm_rf_depth_pat(namebuf, depth - 1, pat) : 0;
195 		else
196 			ret = unlink(namebuf);
197 	}
198 	closedir(dir);
199 
200 	if (ret < 0)
201 		return ret;
202 
203 	return rmdir(path);
204 }
205 
206 static int rm_rf_a_kcore_dir(const char *path, const char *name)
207 {
208 	char kcore_dir_path[PATH_MAX];
209 	const char *pat[] = {
210 		"kcore",
211 		"kallsyms",
212 		"modules",
213 		NULL,
214 	};
215 
216 	snprintf(kcore_dir_path, sizeof(kcore_dir_path), "%s/%s", path, name);
217 
218 	return rm_rf_depth_pat(kcore_dir_path, 0, pat);
219 }
220 
221 static bool kcore_dir_filter(const char *name __maybe_unused, struct dirent *d)
222 {
223 	const char *pat[] = {
224 		"kcore_dir",
225 		"kcore_dir__[1-9]*",
226 		NULL,
227 	};
228 
229 	return match_pat(d->d_name, pat);
230 }
231 
232 static int rm_rf_kcore_dir(const char *path)
233 {
234 	struct strlist *kcore_dirs;
235 	struct str_node *nd;
236 	int ret;
237 
238 	kcore_dirs = lsdir(path, kcore_dir_filter);
239 
240 	if (!kcore_dirs)
241 		return 0;
242 
243 	strlist__for_each_entry(nd, kcore_dirs) {
244 		ret = rm_rf_a_kcore_dir(path, nd->s);
245 		if (ret)
246 			return ret;
247 	}
248 
249 	strlist__delete(kcore_dirs);
250 
251 	return 0;
252 }
253 
254 int rm_rf_perf_data(const char *path)
255 {
256 	const char *pat[] = {
257 		"data",
258 		"data.*",
259 		NULL,
260 	};
261 
262 	rm_rf_kcore_dir(path);
263 
264 	return rm_rf_depth_pat(path, 0, pat);
265 }
266 
267 int rm_rf(const char *path)
268 {
269 	return rm_rf_depth_pat(path, INT_MAX, NULL);
270 }
271 
272 /* A filter which removes dot files */
273 bool lsdir_no_dot_filter(const char *name __maybe_unused, struct dirent *d)
274 {
275 	return d->d_name[0] != '.';
276 }
277 
278 /* lsdir reads a directory and store it in strlist */
279 struct strlist *lsdir(const char *name,
280 		      bool (*filter)(const char *, struct dirent *))
281 {
282 	struct strlist *list = NULL;
283 	DIR *dir;
284 	struct dirent *d;
285 
286 	dir = opendir(name);
287 	if (!dir)
288 		return NULL;
289 
290 	list = strlist__new(NULL, NULL);
291 	if (!list) {
292 		errno = ENOMEM;
293 		goto out;
294 	}
295 
296 	while ((d = readdir(dir)) != NULL) {
297 		if (!filter || filter(name, d))
298 			strlist__add(list, d->d_name);
299 	}
300 
301 out:
302 	closedir(dir);
303 	return list;
304 }
305 
306 size_t hex_width(u64 v)
307 {
308 	size_t n = 1;
309 
310 	while ((v >>= 4))
311 		++n;
312 
313 	return n;
314 }
315 
316 int perf_event_paranoid(void)
317 {
318 	int value;
319 
320 	if (sysctl__read_int("kernel/perf_event_paranoid", &value))
321 		return INT_MAX;
322 
323 	return value;
324 }
325 
326 bool perf_event_paranoid_check(int max_level)
327 {
328 	bool used_root;
329 
330 	if (perf_cap__capable(CAP_SYS_ADMIN, &used_root))
331 		return true;
332 
333 	if (!used_root && perf_cap__capable(CAP_PERFMON, &used_root))
334 		return true;
335 
336 	return perf_event_paranoid() <= max_level;
337 }
338 
339 static int
340 fetch_ubuntu_kernel_version(unsigned int *puint)
341 {
342 	ssize_t len;
343 	size_t line_len = 0;
344 	char *ptr, *line = NULL;
345 	int version, patchlevel, sublevel, err;
346 	FILE *vsig;
347 
348 	if (!puint)
349 		return 0;
350 
351 	vsig = fopen("/proc/version_signature", "r");
352 	if (!vsig) {
353 		pr_debug("Open /proc/version_signature failed: %s\n",
354 			 strerror(errno));
355 		return -1;
356 	}
357 
358 	len = getline(&line, &line_len, vsig);
359 	fclose(vsig);
360 	err = -1;
361 	if (len <= 0) {
362 		pr_debug("Reading from /proc/version_signature failed: %s\n",
363 			 strerror(errno));
364 		goto errout;
365 	}
366 
367 	ptr = strrchr(line, ' ');
368 	if (!ptr) {
369 		pr_debug("Parsing /proc/version_signature failed: %s\n", line);
370 		goto errout;
371 	}
372 
373 	err = sscanf(ptr + 1, "%d.%d.%d",
374 		     &version, &patchlevel, &sublevel);
375 	if (err != 3) {
376 		pr_debug("Unable to get kernel version from /proc/version_signature '%s'\n",
377 			 line);
378 		goto errout;
379 	}
380 
381 	*puint = (version << 16) + (patchlevel << 8) + sublevel;
382 	err = 0;
383 errout:
384 	free(line);
385 	return err;
386 }
387 
388 int
389 fetch_kernel_version(unsigned int *puint, char *str,
390 		     size_t str_size)
391 {
392 	struct utsname utsname;
393 	int version, patchlevel, sublevel, err;
394 	bool int_ver_ready = false;
395 
396 	if (access("/proc/version_signature", R_OK) == 0)
397 		if (!fetch_ubuntu_kernel_version(puint))
398 			int_ver_ready = true;
399 
400 	if (uname(&utsname))
401 		return -1;
402 
403 	if (str && str_size) {
404 		strncpy(str, utsname.release, str_size);
405 		str[str_size - 1] = '\0';
406 	}
407 
408 	if (!puint || int_ver_ready)
409 		return 0;
410 
411 	err = sscanf(utsname.release, "%d.%d.%d",
412 		     &version, &patchlevel, &sublevel);
413 
414 	if (err != 3) {
415 		pr_debug("Unable to get kernel version from uname '%s'\n",
416 			 utsname.release);
417 		return -1;
418 	}
419 
420 	*puint = (version << 16) + (patchlevel << 8) + sublevel;
421 	return 0;
422 }
423 
424 int perf_tip(char **strp, const char *dirpath)
425 {
426 	struct strlist *tips;
427 	struct str_node *node;
428 	struct strlist_config conf = {
429 		.dirname = dirpath,
430 		.file_only = true,
431 	};
432 	int ret = 0;
433 
434 	*strp = NULL;
435 	tips = strlist__new("tips.txt", &conf);
436 	if (tips == NULL)
437 		return -errno;
438 
439 	if (strlist__nr_entries(tips) == 0)
440 		goto out;
441 
442 	node = strlist__entry(tips, random() % strlist__nr_entries(tips));
443 	if (asprintf(strp, "Tip: %s", node->s) < 0)
444 		ret = -ENOMEM;
445 
446 out:
447 	strlist__delete(tips);
448 
449 	return ret;
450 }
451 
452 char *perf_exe(char *buf, int len)
453 {
454 	int n = readlink("/proc/self/exe", buf, len);
455 	if (n > 0) {
456 		buf[n] = 0;
457 		return buf;
458 	}
459 	return strcpy(buf, "perf");
460 }
461 
462 void perf_debuginfod_setup(struct perf_debuginfod *di)
463 {
464 	/*
465 	 * By default '!di->set' we clear DEBUGINFOD_URLS, so debuginfod
466 	 * processing is not triggered, otherwise we set it to 'di->urls'
467 	 * value. If 'di->urls' is "system" we keep DEBUGINFOD_URLS value.
468 	 */
469 	if (!di->set)
470 		setenv("DEBUGINFOD_URLS", "", 1);
471 	else if (di->urls && strcmp(di->urls, "system"))
472 		setenv("DEBUGINFOD_URLS", di->urls, 1);
473 
474 	pr_debug("DEBUGINFOD_URLS=%s\n", getenv("DEBUGINFOD_URLS"));
475 
476 #ifndef HAVE_DEBUGINFOD_SUPPORT
477 	if (di->set)
478 		pr_warning("WARNING: debuginfod support requested, but perf is not built with it\n");
479 #endif
480 }
481 
482 /*
483  * Return a new filename prepended with task's root directory if it's in
484  * a chroot.  Callers should free the returned string.
485  */
486 char *filename_with_chroot(int pid, const char *filename)
487 {
488 	char buf[PATH_MAX];
489 	char proc_root[32];
490 	char *new_name = NULL;
491 	int ret;
492 
493 	scnprintf(proc_root, sizeof(proc_root), "/proc/%d/root", pid);
494 	ret = readlink(proc_root, buf, sizeof(buf) - 1);
495 	if (ret <= 0)
496 		return NULL;
497 
498 	/* readlink(2) does not append a null byte to buf */
499 	buf[ret] = '\0';
500 
501 	if (!strcmp(buf, "/"))
502 		return NULL;
503 
504 	if (strstr(buf, "(deleted)"))
505 		return NULL;
506 
507 	if (asprintf(&new_name, "%s/%s", buf, filename) < 0)
508 		return NULL;
509 
510 	return new_name;
511 }
512 
513 /*
514  * Reallocate an array *arr of size *arr_sz so that it is big enough to contain
515  * x elements of size msz, initializing new entries to *init_val or zero if
516  * init_val is NULL
517  */
518 int do_realloc_array_as_needed(void **arr, size_t *arr_sz, size_t x, size_t msz, const void *init_val)
519 {
520 	size_t new_sz = *arr_sz;
521 	void *new_arr;
522 	size_t i;
523 
524 	if (!new_sz)
525 		new_sz = msz >= 64 ? 1 : roundup(64, msz); /* Start with at least 64 bytes */
526 	while (x >= new_sz) {
527 		if (check_mul_overflow(new_sz, (size_t)2, &new_sz))
528 			return -ENOMEM;
529 	}
530 	if (new_sz == *arr_sz)
531 		return 0;
532 	new_arr = calloc(new_sz, msz);
533 	if (!new_arr)
534 		return -ENOMEM;
535 	if (*arr_sz)
536 		memcpy(new_arr, *arr, *arr_sz * msz);
537 	if (init_val) {
538 		for (i = *arr_sz; i < new_sz; i++)
539 			memcpy(new_arr + (i * msz), init_val, msz);
540 	}
541 	*arr = new_arr;
542 	*arr_sz = new_sz;
543 	return 0;
544 }
545 
546 #ifndef HAVE_SCHED_GETCPU_SUPPORT
547 int sched_getcpu(void)
548 {
549 #ifdef __NR_getcpu
550 	unsigned int cpu;
551 	int err = syscall(__NR_getcpu, &cpu, NULL, NULL);
552 
553 	if (!err)
554 		return cpu;
555 #else
556 	errno = ENOSYS;
557 #endif
558 	return -1;
559 }
560 #endif
561 
562 #ifndef HAVE_SCANDIRAT_SUPPORT
563 int scandirat(int dirfd, const char *dirp,
564 	      struct dirent ***namelist,
565 	      int (*filter)(const struct dirent *),
566 	      int (*compar)(const struct dirent **, const struct dirent **))
567 {
568 	char path[PATH_MAX];
569 	int err, fd = openat(dirfd, dirp, O_PATH);
570 
571 	if (fd < 0)
572 		return fd;
573 
574 	snprintf(path, sizeof(path), "/proc/%d/fd/%d", getpid(), fd);
575 	err = scandir(path, namelist, filter, compar);
576 	close(fd);
577 	return err;
578 }
579 #endif
580