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 <unistd.h>
22 #include "cap.h"
23 #include "strlist.h"
24 #include "string2.h"
25 
26 /*
27  * XXX We need to find a better place for these things...
28  */
29 
30 bool perf_singlethreaded = true;
31 
perf_set_singlethreaded(void)32 void perf_set_singlethreaded(void)
33 {
34 	perf_singlethreaded = true;
35 }
36 
perf_set_multithreaded(void)37 void perf_set_multithreaded(void)
38 {
39 	perf_singlethreaded = false;
40 }
41 
42 int sysctl_perf_event_max_stack = PERF_MAX_STACK_DEPTH;
43 int sysctl_perf_event_max_contexts_per_stack = PERF_MAX_CONTEXTS_PER_STACK;
44 
sysctl__max_stack(void)45 int sysctl__max_stack(void)
46 {
47 	int value;
48 
49 	if (sysctl__read_int("kernel/perf_event_max_stack", &value) == 0)
50 		sysctl_perf_event_max_stack = value;
51 
52 	if (sysctl__read_int("kernel/perf_event_max_contexts_per_stack", &value) == 0)
53 		sysctl_perf_event_max_contexts_per_stack = value;
54 
55 	return sysctl_perf_event_max_stack;
56 }
57 
sysctl__nmi_watchdog_enabled(void)58 bool sysctl__nmi_watchdog_enabled(void)
59 {
60 	static bool cached;
61 	static bool nmi_watchdog;
62 	int value;
63 
64 	if (cached)
65 		return nmi_watchdog;
66 
67 	if (sysctl__read_int("kernel/nmi_watchdog", &value) < 0)
68 		return false;
69 
70 	nmi_watchdog = (value > 0) ? true : false;
71 	cached = true;
72 
73 	return nmi_watchdog;
74 }
75 
76 bool test_attr__enabled;
77 
78 bool perf_host  = true;
79 bool perf_guest = false;
80 
event_attr_init(struct perf_event_attr * attr)81 void event_attr_init(struct perf_event_attr *attr)
82 {
83 	if (!perf_host)
84 		attr->exclude_host  = 1;
85 	if (!perf_guest)
86 		attr->exclude_guest = 1;
87 	/* to capture ABI version */
88 	attr->size = sizeof(*attr);
89 }
90 
mkdir_p(char * path,mode_t mode)91 int mkdir_p(char *path, mode_t mode)
92 {
93 	struct stat st;
94 	int err;
95 	char *d = path;
96 
97 	if (*d != '/')
98 		return -1;
99 
100 	if (stat(path, &st) == 0)
101 		return 0;
102 
103 	while (*++d == '/');
104 
105 	while ((d = strchr(d, '/'))) {
106 		*d = '\0';
107 		err = stat(path, &st) && mkdir(path, mode);
108 		*d++ = '/';
109 		if (err)
110 			return -1;
111 		while (*d == '/')
112 			++d;
113 	}
114 	return (stat(path, &st) && mkdir(path, mode)) ? -1 : 0;
115 }
116 
match_pat(char * file,const char ** pat)117 static bool match_pat(char *file, const char **pat)
118 {
119 	int i = 0;
120 
121 	if (!pat)
122 		return true;
123 
124 	while (pat[i]) {
125 		if (strglobmatch(file, pat[i]))
126 			return true;
127 
128 		i++;
129 	}
130 
131 	return false;
132 }
133 
134 /*
135  * The depth specify how deep the removal will go.
136  * 0       - will remove only files under the 'path' directory
137  * 1 .. x  - will dive in x-level deep under the 'path' directory
138  *
139  * If specified the pat is array of string patterns ended with NULL,
140  * which are checked upon every file/directory found. Only matching
141  * ones are removed.
142  *
143  * The function returns:
144  *    0 on success
145  *   -1 on removal failure with errno set
146  *   -2 on pattern failure
147  */
rm_rf_depth_pat(const char * path,int depth,const char ** pat)148 static int rm_rf_depth_pat(const char *path, int depth, const char **pat)
149 {
150 	DIR *dir;
151 	int ret;
152 	struct dirent *d;
153 	char namebuf[PATH_MAX];
154 	struct stat statbuf;
155 
156 	/* Do not fail if there's no file. */
157 	ret = lstat(path, &statbuf);
158 	if (ret)
159 		return 0;
160 
161 	/* Try to remove any file we get. */
162 	if (!(statbuf.st_mode & S_IFDIR))
163 		return unlink(path);
164 
165 	/* We have directory in path. */
166 	dir = opendir(path);
167 	if (dir == NULL)
168 		return -1;
169 
170 	while ((d = readdir(dir)) != NULL && !ret) {
171 
172 		if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
173 			continue;
174 
175 		if (!match_pat(d->d_name, pat)) {
176 			ret =  -2;
177 			break;
178 		}
179 
180 		scnprintf(namebuf, sizeof(namebuf), "%s/%s",
181 			  path, d->d_name);
182 
183 		/* We have to check symbolic link itself */
184 		ret = lstat(namebuf, &statbuf);
185 		if (ret < 0) {
186 			pr_debug("stat failed: %s\n", namebuf);
187 			break;
188 		}
189 
190 		if (S_ISDIR(statbuf.st_mode))
191 			ret = depth ? rm_rf_depth_pat(namebuf, depth - 1, pat) : 0;
192 		else
193 			ret = unlink(namebuf);
194 	}
195 	closedir(dir);
196 
197 	if (ret < 0)
198 		return ret;
199 
200 	return rmdir(path);
201 }
202 
rm_rf_kcore_dir(const char * path)203 static int rm_rf_kcore_dir(const char *path)
204 {
205 	char kcore_dir_path[PATH_MAX];
206 	const char *pat[] = {
207 		"kcore",
208 		"kallsyms",
209 		"modules",
210 		NULL,
211 	};
212 
213 	snprintf(kcore_dir_path, sizeof(kcore_dir_path), "%s/kcore_dir", path);
214 
215 	return rm_rf_depth_pat(kcore_dir_path, 0, pat);
216 }
217 
rm_rf_perf_data(const char * path)218 int rm_rf_perf_data(const char *path)
219 {
220 	const char *pat[] = {
221 		"data",
222 		"data.*",
223 		NULL,
224 	};
225 
226 	rm_rf_kcore_dir(path);
227 
228 	return rm_rf_depth_pat(path, 0, pat);
229 }
230 
rm_rf(const char * path)231 int rm_rf(const char *path)
232 {
233 	return rm_rf_depth_pat(path, INT_MAX, NULL);
234 }
235 
236 /* A filter which removes dot files */
lsdir_no_dot_filter(const char * name __maybe_unused,struct dirent * d)237 bool lsdir_no_dot_filter(const char *name __maybe_unused, struct dirent *d)
238 {
239 	return d->d_name[0] != '.';
240 }
241 
242 /* lsdir reads a directory and store it in strlist */
lsdir(const char * name,bool (* filter)(const char *,struct dirent *))243 struct strlist *lsdir(const char *name,
244 		      bool (*filter)(const char *, struct dirent *))
245 {
246 	struct strlist *list = NULL;
247 	DIR *dir;
248 	struct dirent *d;
249 
250 	dir = opendir(name);
251 	if (!dir)
252 		return NULL;
253 
254 	list = strlist__new(NULL, NULL);
255 	if (!list) {
256 		errno = ENOMEM;
257 		goto out;
258 	}
259 
260 	while ((d = readdir(dir)) != NULL) {
261 		if (!filter || filter(name, d))
262 			strlist__add(list, d->d_name);
263 	}
264 
265 out:
266 	closedir(dir);
267 	return list;
268 }
269 
hex_width(u64 v)270 size_t hex_width(u64 v)
271 {
272 	size_t n = 1;
273 
274 	while ((v >>= 4))
275 		++n;
276 
277 	return n;
278 }
279 
perf_event_paranoid(void)280 int perf_event_paranoid(void)
281 {
282 	int value;
283 
284 	if (sysctl__read_int("kernel/perf_event_paranoid", &value))
285 		return INT_MAX;
286 
287 	return value;
288 }
289 
perf_event_paranoid_check(int max_level)290 bool perf_event_paranoid_check(int max_level)
291 {
292 	return perf_cap__capable(CAP_SYS_ADMIN) ||
293 			perf_cap__capable(CAP_PERFMON) ||
294 			perf_event_paranoid() <= max_level;
295 }
296 
297 static int
fetch_ubuntu_kernel_version(unsigned int * puint)298 fetch_ubuntu_kernel_version(unsigned int *puint)
299 {
300 	ssize_t len;
301 	size_t line_len = 0;
302 	char *ptr, *line = NULL;
303 	int version, patchlevel, sublevel, err;
304 	FILE *vsig;
305 
306 	if (!puint)
307 		return 0;
308 
309 	vsig = fopen("/proc/version_signature", "r");
310 	if (!vsig) {
311 		pr_debug("Open /proc/version_signature failed: %s\n",
312 			 strerror(errno));
313 		return -1;
314 	}
315 
316 	len = getline(&line, &line_len, vsig);
317 	fclose(vsig);
318 	err = -1;
319 	if (len <= 0) {
320 		pr_debug("Reading from /proc/version_signature failed: %s\n",
321 			 strerror(errno));
322 		goto errout;
323 	}
324 
325 	ptr = strrchr(line, ' ');
326 	if (!ptr) {
327 		pr_debug("Parsing /proc/version_signature failed: %s\n", line);
328 		goto errout;
329 	}
330 
331 	err = sscanf(ptr + 1, "%d.%d.%d",
332 		     &version, &patchlevel, &sublevel);
333 	if (err != 3) {
334 		pr_debug("Unable to get kernel version from /proc/version_signature '%s'\n",
335 			 line);
336 		goto errout;
337 	}
338 
339 	*puint = (version << 16) + (patchlevel << 8) + sublevel;
340 	err = 0;
341 errout:
342 	free(line);
343 	return err;
344 }
345 
346 int
fetch_kernel_version(unsigned int * puint,char * str,size_t str_size)347 fetch_kernel_version(unsigned int *puint, char *str,
348 		     size_t str_size)
349 {
350 	struct utsname utsname;
351 	int version, patchlevel, sublevel, err;
352 	bool int_ver_ready = false;
353 
354 	if (access("/proc/version_signature", R_OK) == 0)
355 		if (!fetch_ubuntu_kernel_version(puint))
356 			int_ver_ready = true;
357 
358 	if (uname(&utsname))
359 		return -1;
360 
361 	if (str && str_size) {
362 		strncpy(str, utsname.release, str_size);
363 		str[str_size - 1] = '\0';
364 	}
365 
366 	if (!puint || int_ver_ready)
367 		return 0;
368 
369 	err = sscanf(utsname.release, "%d.%d.%d",
370 		     &version, &patchlevel, &sublevel);
371 
372 	if (err != 3) {
373 		pr_debug("Unable to get kernel version from uname '%s'\n",
374 			 utsname.release);
375 		return -1;
376 	}
377 
378 	*puint = (version << 16) + (patchlevel << 8) + sublevel;
379 	return 0;
380 }
381 
perf_tip(char ** strp,const char * dirpath)382 int perf_tip(char **strp, const char *dirpath)
383 {
384 	struct strlist *tips;
385 	struct str_node *node;
386 	struct strlist_config conf = {
387 		.dirname = dirpath,
388 		.file_only = true,
389 	};
390 	int ret = 0;
391 
392 	*strp = NULL;
393 	tips = strlist__new("tips.txt", &conf);
394 	if (tips == NULL)
395 		return -errno;
396 
397 	if (strlist__nr_entries(tips) == 0)
398 		goto out;
399 
400 	node = strlist__entry(tips, random() % strlist__nr_entries(tips));
401 	if (asprintf(strp, "Tip: %s", node->s) < 0)
402 		ret = -ENOMEM;
403 
404 out:
405 	strlist__delete(tips);
406 
407 	return ret;
408 }
409 
perf_exe(char * buf,int len)410 char *perf_exe(char *buf, int len)
411 {
412 	int n = readlink("/proc/self/exe", buf, len);
413 	if (n > 0) {
414 		buf[n] = 0;
415 		return buf;
416 	}
417 	return strcpy(buf, "perf");
418 }
419 
perf_debuginfod_setup(struct perf_debuginfod * di)420 void perf_debuginfod_setup(struct perf_debuginfod *di)
421 {
422 	/*
423 	 * By default '!di->set' we clear DEBUGINFOD_URLS, so debuginfod
424 	 * processing is not triggered, otherwise we set it to 'di->urls'
425 	 * value. If 'di->urls' is "system" we keep DEBUGINFOD_URLS value.
426 	 */
427 	if (!di->set)
428 		setenv("DEBUGINFOD_URLS", "", 1);
429 	else if (di->urls && strcmp(di->urls, "system"))
430 		setenv("DEBUGINFOD_URLS", di->urls, 1);
431 
432 	pr_debug("DEBUGINFOD_URLS=%s\n", getenv("DEBUGINFOD_URLS"));
433 
434 #ifndef HAVE_DEBUGINFOD_SUPPORT
435 	if (di->set)
436 		pr_warning("WARNING: debuginfod support requested, but perf is not built with it\n");
437 #endif
438 }
439 
440 /*
441  * Return a new filename prepended with task's root directory if it's in
442  * a chroot.  Callers should free the returned string.
443  */
filename_with_chroot(int pid,const char * filename)444 char *filename_with_chroot(int pid, const char *filename)
445 {
446 	char buf[PATH_MAX];
447 	char proc_root[32];
448 	char *new_name = NULL;
449 	int ret;
450 
451 	scnprintf(proc_root, sizeof(proc_root), "/proc/%d/root", pid);
452 	ret = readlink(proc_root, buf, sizeof(buf) - 1);
453 	if (ret <= 0)
454 		return NULL;
455 
456 	/* readlink(2) does not append a null byte to buf */
457 	buf[ret] = '\0';
458 
459 	if (!strcmp(buf, "/"))
460 		return NULL;
461 
462 	if (strstr(buf, "(deleted)"))
463 		return NULL;
464 
465 	if (asprintf(&new_name, "%s/%s", buf, filename) < 0)
466 		return NULL;
467 
468 	return new_name;
469 }
470