xref: /linux/tools/perf/util/util.c (revision fd639726bf15fca8ee1a00dce8e0096d0ad9bd18)
1 // SPDX-License-Identifier: GPL-2.0
2 #include "../perf.h"
3 #include "util.h"
4 #include "debug.h"
5 #include <api/fs/fs.h>
6 #include <sys/mman.h>
7 #include <sys/stat.h>
8 #include <sys/utsname.h>
9 #include <dirent.h>
10 #include <fcntl.h>
11 #include <inttypes.h>
12 #include <signal.h>
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <string.h>
16 #include <errno.h>
17 #include <limits.h>
18 #include <linux/kernel.h>
19 #include <linux/log2.h>
20 #include <linux/time64.h>
21 #include <unistd.h>
22 #include "strlist.h"
23 
24 /*
25  * XXX We need to find a better place for these things...
26  */
27 
28 bool perf_singlethreaded = true;
29 
30 void perf_set_singlethreaded(void)
31 {
32 	perf_singlethreaded = true;
33 }
34 
35 void perf_set_multithreaded(void)
36 {
37 	perf_singlethreaded = false;
38 }
39 
40 unsigned int page_size;
41 int cacheline_size;
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 
46 bool test_attr__enabled;
47 
48 bool perf_host  = true;
49 bool perf_guest = false;
50 
51 void event_attr_init(struct perf_event_attr *attr)
52 {
53 	if (!perf_host)
54 		attr->exclude_host  = 1;
55 	if (!perf_guest)
56 		attr->exclude_guest = 1;
57 	/* to capture ABI version */
58 	attr->size = sizeof(*attr);
59 }
60 
61 int mkdir_p(char *path, mode_t mode)
62 {
63 	struct stat st;
64 	int err;
65 	char *d = path;
66 
67 	if (*d != '/')
68 		return -1;
69 
70 	if (stat(path, &st) == 0)
71 		return 0;
72 
73 	while (*++d == '/');
74 
75 	while ((d = strchr(d, '/'))) {
76 		*d = '\0';
77 		err = stat(path, &st) && mkdir(path, mode);
78 		*d++ = '/';
79 		if (err)
80 			return -1;
81 		while (*d == '/')
82 			++d;
83 	}
84 	return (stat(path, &st) && mkdir(path, mode)) ? -1 : 0;
85 }
86 
87 int rm_rf(const char *path)
88 {
89 	DIR *dir;
90 	int ret = 0;
91 	struct dirent *d;
92 	char namebuf[PATH_MAX];
93 
94 	dir = opendir(path);
95 	if (dir == NULL)
96 		return 0;
97 
98 	while ((d = readdir(dir)) != NULL && !ret) {
99 		struct stat statbuf;
100 
101 		if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
102 			continue;
103 
104 		scnprintf(namebuf, sizeof(namebuf), "%s/%s",
105 			  path, d->d_name);
106 
107 		/* We have to check symbolic link itself */
108 		ret = lstat(namebuf, &statbuf);
109 		if (ret < 0) {
110 			pr_debug("stat failed: %s\n", namebuf);
111 			break;
112 		}
113 
114 		if (S_ISDIR(statbuf.st_mode))
115 			ret = rm_rf(namebuf);
116 		else
117 			ret = unlink(namebuf);
118 	}
119 	closedir(dir);
120 
121 	if (ret < 0)
122 		return ret;
123 
124 	return rmdir(path);
125 }
126 
127 /* A filter which removes dot files */
128 bool lsdir_no_dot_filter(const char *name __maybe_unused, struct dirent *d)
129 {
130 	return d->d_name[0] != '.';
131 }
132 
133 /* lsdir reads a directory and store it in strlist */
134 struct strlist *lsdir(const char *name,
135 		      bool (*filter)(const char *, struct dirent *))
136 {
137 	struct strlist *list = NULL;
138 	DIR *dir;
139 	struct dirent *d;
140 
141 	dir = opendir(name);
142 	if (!dir)
143 		return NULL;
144 
145 	list = strlist__new(NULL, NULL);
146 	if (!list) {
147 		errno = ENOMEM;
148 		goto out;
149 	}
150 
151 	while ((d = readdir(dir)) != NULL) {
152 		if (!filter || filter(name, d))
153 			strlist__add(list, d->d_name);
154 	}
155 
156 out:
157 	closedir(dir);
158 	return list;
159 }
160 
161 static int slow_copyfile(const char *from, const char *to, struct nsinfo *nsi)
162 {
163 	int err = -1;
164 	char *line = NULL;
165 	size_t n;
166 	FILE *from_fp, *to_fp;
167 	struct nscookie nsc;
168 
169 	nsinfo__mountns_enter(nsi, &nsc);
170 	from_fp = fopen(from, "r");
171 	nsinfo__mountns_exit(&nsc);
172 	if (from_fp == NULL)
173 		goto out;
174 
175 	to_fp = fopen(to, "w");
176 	if (to_fp == NULL)
177 		goto out_fclose_from;
178 
179 	while (getline(&line, &n, from_fp) > 0)
180 		if (fputs(line, to_fp) == EOF)
181 			goto out_fclose_to;
182 	err = 0;
183 out_fclose_to:
184 	fclose(to_fp);
185 	free(line);
186 out_fclose_from:
187 	fclose(from_fp);
188 out:
189 	return err;
190 }
191 
192 static int copyfile_offset(int ifd, loff_t off_in, int ofd, loff_t off_out, u64 size)
193 {
194 	void *ptr;
195 	loff_t pgoff;
196 
197 	pgoff = off_in & ~(page_size - 1);
198 	off_in -= pgoff;
199 
200 	ptr = mmap(NULL, off_in + size, PROT_READ, MAP_PRIVATE, ifd, pgoff);
201 	if (ptr == MAP_FAILED)
202 		return -1;
203 
204 	while (size) {
205 		ssize_t ret = pwrite(ofd, ptr + off_in, size, off_out);
206 		if (ret < 0 && errno == EINTR)
207 			continue;
208 		if (ret <= 0)
209 			break;
210 
211 		size -= ret;
212 		off_in += ret;
213 		off_out -= ret;
214 	}
215 	munmap(ptr, off_in + size);
216 
217 	return size ? -1 : 0;
218 }
219 
220 static int copyfile_mode_ns(const char *from, const char *to, mode_t mode,
221 			    struct nsinfo *nsi)
222 {
223 	int fromfd, tofd;
224 	struct stat st;
225 	int err;
226 	char *tmp = NULL, *ptr = NULL;
227 	struct nscookie nsc;
228 
229 	nsinfo__mountns_enter(nsi, &nsc);
230 	err = stat(from, &st);
231 	nsinfo__mountns_exit(&nsc);
232 	if (err)
233 		goto out;
234 	err = -1;
235 
236 	/* extra 'x' at the end is to reserve space for '.' */
237 	if (asprintf(&tmp, "%s.XXXXXXx", to) < 0) {
238 		tmp = NULL;
239 		goto out;
240 	}
241 	ptr = strrchr(tmp, '/');
242 	if (!ptr)
243 		goto out;
244 	ptr = memmove(ptr + 1, ptr, strlen(ptr) - 1);
245 	*ptr = '.';
246 
247 	tofd = mkstemp(tmp);
248 	if (tofd < 0)
249 		goto out;
250 
251 	if (fchmod(tofd, mode))
252 		goto out_close_to;
253 
254 	if (st.st_size == 0) { /* /proc? do it slowly... */
255 		err = slow_copyfile(from, tmp, nsi);
256 		goto out_close_to;
257 	}
258 
259 	nsinfo__mountns_enter(nsi, &nsc);
260 	fromfd = open(from, O_RDONLY);
261 	nsinfo__mountns_exit(&nsc);
262 	if (fromfd < 0)
263 		goto out_close_to;
264 
265 	err = copyfile_offset(fromfd, 0, tofd, 0, st.st_size);
266 
267 	close(fromfd);
268 out_close_to:
269 	close(tofd);
270 	if (!err)
271 		err = link(tmp, to);
272 	unlink(tmp);
273 out:
274 	free(tmp);
275 	return err;
276 }
277 
278 int copyfile_ns(const char *from, const char *to, struct nsinfo *nsi)
279 {
280 	return copyfile_mode_ns(from, to, 0755, nsi);
281 }
282 
283 int copyfile_mode(const char *from, const char *to, mode_t mode)
284 {
285 	return copyfile_mode_ns(from, to, mode, NULL);
286 }
287 
288 int copyfile(const char *from, const char *to)
289 {
290 	return copyfile_mode(from, to, 0755);
291 }
292 
293 static ssize_t ion(bool is_read, int fd, void *buf, size_t n)
294 {
295 	void *buf_start = buf;
296 	size_t left = n;
297 
298 	while (left) {
299 		/* buf must be treated as const if !is_read. */
300 		ssize_t ret = is_read ? read(fd, buf, left) :
301 					write(fd, buf, left);
302 
303 		if (ret < 0 && errno == EINTR)
304 			continue;
305 		if (ret <= 0)
306 			return ret;
307 
308 		left -= ret;
309 		buf  += ret;
310 	}
311 
312 	BUG_ON((size_t)(buf - buf_start) != n);
313 	return n;
314 }
315 
316 /*
317  * Read exactly 'n' bytes or return an error.
318  */
319 ssize_t readn(int fd, void *buf, size_t n)
320 {
321 	return ion(true, fd, buf, n);
322 }
323 
324 /*
325  * Write exactly 'n' bytes or return an error.
326  */
327 ssize_t writen(int fd, const void *buf, size_t n)
328 {
329 	/* ion does not modify buf. */
330 	return ion(false, fd, (void *)buf, n);
331 }
332 
333 size_t hex_width(u64 v)
334 {
335 	size_t n = 1;
336 
337 	while ((v >>= 4))
338 		++n;
339 
340 	return n;
341 }
342 
343 static int hex(char ch)
344 {
345 	if ((ch >= '0') && (ch <= '9'))
346 		return ch - '0';
347 	if ((ch >= 'a') && (ch <= 'f'))
348 		return ch - 'a' + 10;
349 	if ((ch >= 'A') && (ch <= 'F'))
350 		return ch - 'A' + 10;
351 	return -1;
352 }
353 
354 /*
355  * While we find nice hex chars, build a long_val.
356  * Return number of chars processed.
357  */
358 int hex2u64(const char *ptr, u64 *long_val)
359 {
360 	const char *p = ptr;
361 	*long_val = 0;
362 
363 	while (*p) {
364 		const int hex_val = hex(*p);
365 
366 		if (hex_val < 0)
367 			break;
368 
369 		*long_val = (*long_val << 4) | hex_val;
370 		p++;
371 	}
372 
373 	return p - ptr;
374 }
375 
376 int perf_event_paranoid(void)
377 {
378 	int value;
379 
380 	if (sysctl__read_int("kernel/perf_event_paranoid", &value))
381 		return INT_MAX;
382 
383 	return value;
384 }
385 static int
386 fetch_ubuntu_kernel_version(unsigned int *puint)
387 {
388 	ssize_t len;
389 	size_t line_len = 0;
390 	char *ptr, *line = NULL;
391 	int version, patchlevel, sublevel, err;
392 	FILE *vsig;
393 
394 	if (!puint)
395 		return 0;
396 
397 	vsig = fopen("/proc/version_signature", "r");
398 	if (!vsig) {
399 		pr_debug("Open /proc/version_signature failed: %s\n",
400 			 strerror(errno));
401 		return -1;
402 	}
403 
404 	len = getline(&line, &line_len, vsig);
405 	fclose(vsig);
406 	err = -1;
407 	if (len <= 0) {
408 		pr_debug("Reading from /proc/version_signature failed: %s\n",
409 			 strerror(errno));
410 		goto errout;
411 	}
412 
413 	ptr = strrchr(line, ' ');
414 	if (!ptr) {
415 		pr_debug("Parsing /proc/version_signature failed: %s\n", line);
416 		goto errout;
417 	}
418 
419 	err = sscanf(ptr + 1, "%d.%d.%d",
420 		     &version, &patchlevel, &sublevel);
421 	if (err != 3) {
422 		pr_debug("Unable to get kernel version from /proc/version_signature '%s'\n",
423 			 line);
424 		goto errout;
425 	}
426 
427 	*puint = (version << 16) + (patchlevel << 8) + sublevel;
428 	err = 0;
429 errout:
430 	free(line);
431 	return err;
432 }
433 
434 int
435 fetch_kernel_version(unsigned int *puint, char *str,
436 		     size_t str_size)
437 {
438 	struct utsname utsname;
439 	int version, patchlevel, sublevel, err;
440 	bool int_ver_ready = false;
441 
442 	if (access("/proc/version_signature", R_OK) == 0)
443 		if (!fetch_ubuntu_kernel_version(puint))
444 			int_ver_ready = true;
445 
446 	if (uname(&utsname))
447 		return -1;
448 
449 	if (str && str_size) {
450 		strncpy(str, utsname.release, str_size);
451 		str[str_size - 1] = '\0';
452 	}
453 
454 	if (!puint || int_ver_ready)
455 		return 0;
456 
457 	err = sscanf(utsname.release, "%d.%d.%d",
458 		     &version, &patchlevel, &sublevel);
459 
460 	if (err != 3) {
461 		pr_debug("Unable to get kernel version from uname '%s'\n",
462 			 utsname.release);
463 		return -1;
464 	}
465 
466 	*puint = (version << 16) + (patchlevel << 8) + sublevel;
467 	return 0;
468 }
469 
470 const char *perf_tip(const char *dirpath)
471 {
472 	struct strlist *tips;
473 	struct str_node *node;
474 	char *tip = NULL;
475 	struct strlist_config conf = {
476 		.dirname = dirpath,
477 		.file_only = true,
478 	};
479 
480 	tips = strlist__new("tips.txt", &conf);
481 	if (tips == NULL)
482 		return errno == ENOENT ? NULL :
483 			"Tip: check path of tips.txt or get more memory! ;-p";
484 
485 	if (strlist__nr_entries(tips) == 0)
486 		goto out;
487 
488 	node = strlist__entry(tips, random() % strlist__nr_entries(tips));
489 	if (asprintf(&tip, "Tip: %s", node->s) < 0)
490 		tip = (char *)"Tip: get more memory! ;-)";
491 
492 out:
493 	strlist__delete(tips);
494 
495 	return tip;
496 }
497