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