xref: /openbmc/linux/tools/perf/util/util.c (revision f12ad272)
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 
perf_set_singlethreaded(void)35 void perf_set_singlethreaded(void)
36 {
37 	perf_singlethreaded = true;
38 }
39 
perf_set_multithreaded(void)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 
sysctl__max_stack(void)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 
sysctl__nmi_watchdog_enabled(void)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 
event_attr_init(struct perf_event_attr * attr)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 
mkdir_p(char * path,mode_t mode)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 
match_pat(char * file,const char ** pat)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  */
rm_rf_depth_pat(const char * path,int depth,const char ** pat)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 
rm_rf_a_kcore_dir(const char * path,const char * name)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 
kcore_dir_filter(const char * name __maybe_unused,struct dirent * d)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 
rm_rf_kcore_dir(const char * path)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 
rm_rf_perf_data(const char * path)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 
rm_rf(const char * path)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 */
lsdir_no_dot_filter(const char * name __maybe_unused,struct dirent * d)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 */
lsdir(const char * name,bool (* filter)(const char *,struct dirent *))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 
hex_width(u64 v)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 
perf_event_paranoid(void)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 
perf_event_paranoid_check(int max_level)326 bool perf_event_paranoid_check(int max_level)
327 {
328 	return perf_cap__capable(CAP_SYS_ADMIN) ||
329 			perf_cap__capable(CAP_PERFMON) ||
330 			perf_event_paranoid() <= max_level;
331 }
332 
333 static int
fetch_ubuntu_kernel_version(unsigned int * puint)334 fetch_ubuntu_kernel_version(unsigned int *puint)
335 {
336 	ssize_t len;
337 	size_t line_len = 0;
338 	char *ptr, *line = NULL;
339 	int version, patchlevel, sublevel, err;
340 	FILE *vsig;
341 
342 	if (!puint)
343 		return 0;
344 
345 	vsig = fopen("/proc/version_signature", "r");
346 	if (!vsig) {
347 		pr_debug("Open /proc/version_signature failed: %s\n",
348 			 strerror(errno));
349 		return -1;
350 	}
351 
352 	len = getline(&line, &line_len, vsig);
353 	fclose(vsig);
354 	err = -1;
355 	if (len <= 0) {
356 		pr_debug("Reading from /proc/version_signature failed: %s\n",
357 			 strerror(errno));
358 		goto errout;
359 	}
360 
361 	ptr = strrchr(line, ' ');
362 	if (!ptr) {
363 		pr_debug("Parsing /proc/version_signature failed: %s\n", line);
364 		goto errout;
365 	}
366 
367 	err = sscanf(ptr + 1, "%d.%d.%d",
368 		     &version, &patchlevel, &sublevel);
369 	if (err != 3) {
370 		pr_debug("Unable to get kernel version from /proc/version_signature '%s'\n",
371 			 line);
372 		goto errout;
373 	}
374 
375 	*puint = (version << 16) + (patchlevel << 8) + sublevel;
376 	err = 0;
377 errout:
378 	free(line);
379 	return err;
380 }
381 
382 int
fetch_kernel_version(unsigned int * puint,char * str,size_t str_size)383 fetch_kernel_version(unsigned int *puint, char *str,
384 		     size_t str_size)
385 {
386 	struct utsname utsname;
387 	int version, patchlevel, sublevel, err;
388 	bool int_ver_ready = false;
389 
390 	if (access("/proc/version_signature", R_OK) == 0)
391 		if (!fetch_ubuntu_kernel_version(puint))
392 			int_ver_ready = true;
393 
394 	if (uname(&utsname))
395 		return -1;
396 
397 	if (str && str_size) {
398 		strncpy(str, utsname.release, str_size);
399 		str[str_size - 1] = '\0';
400 	}
401 
402 	if (!puint || int_ver_ready)
403 		return 0;
404 
405 	err = sscanf(utsname.release, "%d.%d.%d",
406 		     &version, &patchlevel, &sublevel);
407 
408 	if (err != 3) {
409 		pr_debug("Unable to get kernel version from uname '%s'\n",
410 			 utsname.release);
411 		return -1;
412 	}
413 
414 	*puint = (version << 16) + (patchlevel << 8) + sublevel;
415 	return 0;
416 }
417 
perf_tip(char ** strp,const char * dirpath)418 int perf_tip(char **strp, const char *dirpath)
419 {
420 	struct strlist *tips;
421 	struct str_node *node;
422 	struct strlist_config conf = {
423 		.dirname = dirpath,
424 		.file_only = true,
425 	};
426 	int ret = 0;
427 
428 	*strp = NULL;
429 	tips = strlist__new("tips.txt", &conf);
430 	if (tips == NULL)
431 		return -errno;
432 
433 	if (strlist__nr_entries(tips) == 0)
434 		goto out;
435 
436 	node = strlist__entry(tips, random() % strlist__nr_entries(tips));
437 	if (asprintf(strp, "Tip: %s", node->s) < 0)
438 		ret = -ENOMEM;
439 
440 out:
441 	strlist__delete(tips);
442 
443 	return ret;
444 }
445 
perf_exe(char * buf,int len)446 char *perf_exe(char *buf, int len)
447 {
448 	int n = readlink("/proc/self/exe", buf, len);
449 	if (n > 0) {
450 		buf[n] = 0;
451 		return buf;
452 	}
453 	return strcpy(buf, "perf");
454 }
455 
perf_debuginfod_setup(struct perf_debuginfod * di)456 void perf_debuginfod_setup(struct perf_debuginfod *di)
457 {
458 	/*
459 	 * By default '!di->set' we clear DEBUGINFOD_URLS, so debuginfod
460 	 * processing is not triggered, otherwise we set it to 'di->urls'
461 	 * value. If 'di->urls' is "system" we keep DEBUGINFOD_URLS value.
462 	 */
463 	if (!di->set)
464 		setenv("DEBUGINFOD_URLS", "", 1);
465 	else if (di->urls && strcmp(di->urls, "system"))
466 		setenv("DEBUGINFOD_URLS", di->urls, 1);
467 
468 	pr_debug("DEBUGINFOD_URLS=%s\n", getenv("DEBUGINFOD_URLS"));
469 
470 #ifndef HAVE_DEBUGINFOD_SUPPORT
471 	if (di->set)
472 		pr_warning("WARNING: debuginfod support requested, but perf is not built with it\n");
473 #endif
474 }
475 
476 /*
477  * Return a new filename prepended with task's root directory if it's in
478  * a chroot.  Callers should free the returned string.
479  */
filename_with_chroot(int pid,const char * filename)480 char *filename_with_chroot(int pid, const char *filename)
481 {
482 	char buf[PATH_MAX];
483 	char proc_root[32];
484 	char *new_name = NULL;
485 	int ret;
486 
487 	scnprintf(proc_root, sizeof(proc_root), "/proc/%d/root", pid);
488 	ret = readlink(proc_root, buf, sizeof(buf) - 1);
489 	if (ret <= 0)
490 		return NULL;
491 
492 	/* readlink(2) does not append a null byte to buf */
493 	buf[ret] = '\0';
494 
495 	if (!strcmp(buf, "/"))
496 		return NULL;
497 
498 	if (strstr(buf, "(deleted)"))
499 		return NULL;
500 
501 	if (asprintf(&new_name, "%s/%s", buf, filename) < 0)
502 		return NULL;
503 
504 	return new_name;
505 }
506 
507 /*
508  * Reallocate an array *arr of size *arr_sz so that it is big enough to contain
509  * x elements of size msz, initializing new entries to *init_val or zero if
510  * init_val is NULL
511  */
do_realloc_array_as_needed(void ** arr,size_t * arr_sz,size_t x,size_t msz,const void * init_val)512 int do_realloc_array_as_needed(void **arr, size_t *arr_sz, size_t x, size_t msz, const void *init_val)
513 {
514 	size_t new_sz = *arr_sz;
515 	void *new_arr;
516 	size_t i;
517 
518 	if (!new_sz)
519 		new_sz = msz >= 64 ? 1 : roundup(64, msz); /* Start with at least 64 bytes */
520 	while (x >= new_sz) {
521 		if (check_mul_overflow(new_sz, (size_t)2, &new_sz))
522 			return -ENOMEM;
523 	}
524 	if (new_sz == *arr_sz)
525 		return 0;
526 	new_arr = calloc(new_sz, msz);
527 	if (!new_arr)
528 		return -ENOMEM;
529 	if (*arr_sz)
530 		memcpy(new_arr, *arr, *arr_sz * msz);
531 	if (init_val) {
532 		for (i = *arr_sz; i < new_sz; i++)
533 			memcpy(new_arr + (i * msz), init_val, msz);
534 	}
535 	*arr = new_arr;
536 	*arr_sz = new_sz;
537 	return 0;
538 }
539 
540 #ifndef HAVE_SCHED_GETCPU_SUPPORT
sched_getcpu(void)541 int sched_getcpu(void)
542 {
543 #ifdef __NR_getcpu
544 	unsigned int cpu;
545 	int err = syscall(__NR_getcpu, &cpu, NULL, NULL);
546 
547 	if (!err)
548 		return cpu;
549 #else
550 	errno = ENOSYS;
551 #endif
552 	return -1;
553 }
554 #endif
555