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
31const char *input_name;
32
33bool perf_singlethreaded = true;
34
35void perf_set_singlethreaded(void)
36{
37 perf_singlethreaded = true;
38}
39
40void perf_set_multithreaded(void)
41{
42 perf_singlethreaded = false;
43}
44
45int sysctl_perf_event_max_stack = PERF_MAX_STACK_DEPTH;
46int sysctl_perf_event_max_contexts_per_stack = PERF_MAX_CONTEXTS_PER_STACK;
47
48int 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
61bool 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
79bool test_attr__enabled;
80
81bool exclude_GH_default;
82
83bool perf_host = true;
84bool perf_guest = false;
85
86void event_attr_init(struct perf_event_attr *attr)
87{
88 /* to capture ABI version */
89 attr->size = sizeof(*attr);
90
91 if (!exclude_GH_default)
92 return;
93
94 if (!perf_host)
95 attr->exclude_host = 1;
96 if (!perf_guest)
97 attr->exclude_guest = 1;
98}
99
100int mkdir_p(char *path, mode_t mode)
101{
102 struct stat st;
103 int err;
104 char *d = path;
105
106 if (*d != '/')
107 return -1;
108
109 if (stat(path, &st) == 0)
110 return 0;
111
112 while (*++d == '/');
113
114 while ((d = strchr(d, '/'))) {
115 *d = '\0';
116 err = stat(path, &st) && mkdir(path, mode);
117 *d++ = '/';
118 if (err)
119 return -1;
120 while (*d == '/')
121 ++d;
122 }
123 return (stat(path, &st) && mkdir(path, mode)) ? -1 : 0;
124}
125
126static bool match_pat(char *file, const char **pat)
127{
128 int i = 0;
129
130 if (!pat)
131 return true;
132
133 while (pat[i]) {
134 if (strglobmatch(str: file, pat: pat[i]))
135 return true;
136
137 i++;
138 }
139
140 return false;
141}
142
143/*
144 * The depth specify how deep the removal will go.
145 * 0 - will remove only files under the 'path' directory
146 * 1 .. x - will dive in x-level deep under the 'path' directory
147 *
148 * If specified the pat is array of string patterns ended with NULL,
149 * which are checked upon every file/directory found. Only matching
150 * ones are removed.
151 *
152 * The function returns:
153 * 0 on success
154 * -1 on removal failure with errno set
155 * -2 on pattern failure
156 */
157static int rm_rf_depth_pat(const char *path, int depth, const char **pat)
158{
159 DIR *dir;
160 int ret;
161 struct dirent *d;
162 char namebuf[PATH_MAX];
163 struct stat statbuf;
164
165 /* Do not fail if there's no file. */
166 ret = lstat(path, &statbuf);
167 if (ret)
168 return 0;
169
170 /* Try to remove any file we get. */
171 if (!(statbuf.st_mode & S_IFDIR))
172 return unlink(path);
173
174 /* We have directory in path. */
175 dir = opendir(path);
176 if (dir == NULL)
177 return -1;
178
179 while ((d = readdir(dir)) != NULL && !ret) {
180
181 if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
182 continue;
183
184 if (!match_pat(file: d->d_name, pat)) {
185 ret = -2;
186 break;
187 }
188
189 scnprintf(buf: namebuf, size: sizeof(namebuf), fmt: "%s/%s",
190 path, d->d_name);
191
192 /* We have to check symbolic link itself */
193 ret = lstat(namebuf, &statbuf);
194 if (ret < 0) {
195 pr_debug("stat failed: %s\n", namebuf);
196 break;
197 }
198
199 if (S_ISDIR(statbuf.st_mode))
200 ret = depth ? rm_rf_depth_pat(path: namebuf, depth: depth - 1, pat) : 0;
201 else
202 ret = unlink(namebuf);
203 }
204 closedir(dir);
205
206 if (ret < 0)
207 return ret;
208
209 return rmdir(path);
210}
211
212static int rm_rf_a_kcore_dir(const char *path, const char *name)
213{
214 char kcore_dir_path[PATH_MAX];
215 const char *pat[] = {
216 "kcore",
217 "kallsyms",
218 "modules",
219 NULL,
220 };
221
222 snprintf(buf: kcore_dir_path, size: sizeof(kcore_dir_path), fmt: "%s/%s", path, name);
223
224 return rm_rf_depth_pat(path: kcore_dir_path, depth: 0, pat);
225}
226
227static bool kcore_dir_filter(const char *name __maybe_unused, struct dirent *d)
228{
229 const char *pat[] = {
230 "kcore_dir",
231 "kcore_dir__[1-9]*",
232 NULL,
233 };
234
235 return match_pat(file: d->d_name, pat);
236}
237
238static int rm_rf_kcore_dir(const char *path)
239{
240 struct strlist *kcore_dirs;
241 struct str_node *nd;
242 int ret;
243
244 kcore_dirs = lsdir(name: path, filter: kcore_dir_filter);
245
246 if (!kcore_dirs)
247 return 0;
248
249 strlist__for_each_entry(nd, kcore_dirs) {
250 ret = rm_rf_a_kcore_dir(path, name: nd->s);
251 if (ret)
252 return ret;
253 }
254
255 strlist__delete(slist: kcore_dirs);
256
257 return 0;
258}
259
260int rm_rf_perf_data(const char *path)
261{
262 const char *pat[] = {
263 "data",
264 "data.*",
265 NULL,
266 };
267
268 rm_rf_kcore_dir(path);
269
270 return rm_rf_depth_pat(path, depth: 0, pat);
271}
272
273int rm_rf(const char *path)
274{
275 return rm_rf_depth_pat(path, INT_MAX, NULL);
276}
277
278/* A filter which removes dot files */
279bool lsdir_no_dot_filter(const char *name __maybe_unused, struct dirent *d)
280{
281 return d->d_name[0] != '.';
282}
283
284/* lsdir reads a directory and store it in strlist */
285struct strlist *lsdir(const char *name,
286 bool (*filter)(const char *, struct dirent *))
287{
288 struct strlist *list = NULL;
289 DIR *dir;
290 struct dirent *d;
291
292 dir = opendir(name);
293 if (!dir)
294 return NULL;
295
296 list = strlist__new(NULL, NULL);
297 if (!list) {
298 errno = ENOMEM;
299 goto out;
300 }
301
302 while ((d = readdir(dir)) != NULL) {
303 if (!filter || filter(name, d))
304 strlist__add(slist: list, str: d->d_name);
305 }
306
307out:
308 closedir(dir);
309 return list;
310}
311
312size_t hex_width(u64 v)
313{
314 size_t n = 1;
315
316 while ((v >>= 4))
317 ++n;
318
319 return n;
320}
321
322int perf_event_paranoid(void)
323{
324 int value;
325
326 if (sysctl__read_int("kernel/perf_event_paranoid", &value))
327 return INT_MAX;
328
329 return value;
330}
331
332bool perf_event_paranoid_check(int max_level)
333{
334 bool used_root;
335
336 if (perf_cap__capable(CAP_SYS_ADMIN, used_root: &used_root))
337 return true;
338
339 if (!used_root && perf_cap__capable(CAP_PERFMON, used_root: &used_root))
340 return true;
341
342 return perf_event_paranoid() <= max_level;
343}
344
345int perf_tip(char **strp, const char *dirpath)
346{
347 struct strlist *tips;
348 struct str_node *node;
349 struct strlist_config conf = {
350 .dirname = dirpath,
351 .file_only = true,
352 };
353 int ret = 0;
354
355 *strp = NULL;
356 tips = strlist__new(slist: "tips.txt", config: &conf);
357 if (tips == NULL)
358 return -errno;
359
360 if (strlist__nr_entries(slist: tips) == 0)
361 goto out;
362
363 node = strlist__entry(slist: tips, idx: random() % strlist__nr_entries(slist: tips));
364 if (asprintf(strp, "Tip: %s", node->s) < 0)
365 ret = -ENOMEM;
366
367out:
368 strlist__delete(slist: tips);
369
370 return ret;
371}
372
373char *perf_exe(char *buf, int len)
374{
375 int n = readlink("/proc/self/exe", buf, len);
376 if (n > 0) {
377 buf[n] = 0;
378 return buf;
379 }
380 return strcpy(p: buf, q: "perf");
381}
382
383void perf_debuginfod_setup(struct perf_debuginfod *di)
384{
385 /*
386 * By default '!di->set' we clear DEBUGINFOD_URLS, so debuginfod
387 * processing is not triggered, otherwise we set it to 'di->urls'
388 * value. If 'di->urls' is "system" we keep DEBUGINFOD_URLS value.
389 */
390 if (!di->set)
391 setenv("DEBUGINFOD_URLS", "", 1);
392 else if (di->urls && strcmp(di->urls, "system"))
393 setenv("DEBUGINFOD_URLS", di->urls, 1);
394
395 pr_debug("DEBUGINFOD_URLS=%s\n", getenv("DEBUGINFOD_URLS"));
396
397#ifndef HAVE_DEBUGINFOD_SUPPORT
398 if (di->set)
399 pr_warning("WARNING: debuginfod support requested, but perf is not built with it\n");
400#endif
401}
402
403/*
404 * Return a new filename prepended with task's root directory if it's in
405 * a chroot. Callers should free the returned string.
406 */
407char *filename_with_chroot(int pid, const char *filename)
408{
409 char buf[PATH_MAX];
410 char proc_root[32];
411 char *new_name = NULL;
412 int ret;
413
414 scnprintf(buf: proc_root, size: sizeof(proc_root), fmt: "/proc/%d/root", pid);
415 ret = readlink(proc_root, buf, sizeof(buf) - 1);
416 if (ret <= 0)
417 return NULL;
418
419 /* readlink(2) does not append a null byte to buf */
420 buf[ret] = '\0';
421
422 if (!strcmp(buf, "/"))
423 return NULL;
424
425 if (strstr(buf, "(deleted)"))
426 return NULL;
427
428 if (asprintf(&new_name, "%s/%s", buf, filename) < 0)
429 return NULL;
430
431 return new_name;
432}
433
434/*
435 * Reallocate an array *arr of size *arr_sz so that it is big enough to contain
436 * x elements of size msz, initializing new entries to *init_val or zero if
437 * init_val is NULL
438 */
439int do_realloc_array_as_needed(void **arr, size_t *arr_sz, size_t x, size_t msz, const void *init_val)
440{
441 size_t new_sz = *arr_sz;
442 void *new_arr;
443 size_t i;
444
445 if (!new_sz)
446 new_sz = msz >= 64 ? 1 : roundup(64, msz); /* Start with at least 64 bytes */
447 while (x >= new_sz) {
448 if (check_mul_overflow(new_sz, (size_t)2, &new_sz))
449 return -ENOMEM;
450 }
451 if (new_sz == *arr_sz)
452 return 0;
453 new_arr = calloc(new_sz, msz);
454 if (!new_arr)
455 return -ENOMEM;
456 if (*arr_sz)
457 memcpy(new_arr, *arr, *arr_sz * msz);
458 if (init_val) {
459 for (i = *arr_sz; i < new_sz; i++)
460 memcpy(new_arr + (i * msz), init_val, msz);
461 }
462 *arr = new_arr;
463 *arr_sz = new_sz;
464 return 0;
465}
466
467#ifndef HAVE_SCHED_GETCPU_SUPPORT
468int sched_getcpu(void)
469{
470#ifdef __NR_getcpu
471 unsigned int cpu;
472 int err = syscall(__NR_getcpu, &cpu, NULL, NULL);
473
474 if (!err)
475 return cpu;
476#else
477 errno = ENOSYS;
478#endif
479 return -1;
480}
481#endif
482
483#ifndef HAVE_SCANDIRAT_SUPPORT
484int scandirat(int dirfd, const char *dirp,
485 struct dirent ***namelist,
486 int (*filter)(const struct dirent *),
487 int (*compar)(const struct dirent **, const struct dirent **))
488{
489 char path[PATH_MAX];
490 int err, fd = openat(dirfd, dirp, O_PATH);
491
492 if (fd < 0)
493 return fd;
494
495 snprintf(buf: path, size: sizeof(path), fmt: "/proc/%d/fd/%d", getpid(), fd);
496 err = scandir(path, namelist, filter, compar);
497 close(fd);
498 return err;
499}
500#endif
501

source code of linux/tools/perf/util/util.c