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 perf_host  = true;
82bool perf_guest = false;
83
84void 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
94int 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
120static 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 */
151static 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
206static 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
221static 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
232static 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
254int 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
267int 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 */
273bool 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 */
279struct 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
301out:
302	closedir(dir);
303	return list;
304}
305
306size_t hex_width(u64 v)
307{
308	size_t n = 1;
309
310	while ((v >>= 4))
311		++n;
312
313	return n;
314}
315
316int 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
326bool 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
333static int
334fetch_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;
377errout:
378	free(line);
379	return err;
380}
381
382int
383fetch_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
418int 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
440out:
441	strlist__delete(tips);
442
443	return ret;
444}
445
446char *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
456void 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 */
480char *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 */
512int 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
541int 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
556#ifndef HAVE_SCANDIRAT_SUPPORT
557int scandirat(int dirfd, const char *dirp,
558	      struct dirent ***namelist,
559	      int (*filter)(const struct dirent *),
560	      int (*compar)(const struct dirent **, const struct dirent **))
561{
562	char path[PATH_MAX];
563	int err, fd = openat(dirfd, dirp, O_PATH);
564
565	if (fd < 0)
566		return fd;
567
568	snprintf(path, sizeof(path), "/proc/%d/fd/%d", getpid(), fd);
569	err = scandir(path, namelist, filter, compar);
570	close(fd);
571	return err;
572}
573#endif
574