data.c

  1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/compiler.h>
  3#include <linux/kernel.h>
  4#include <linux/string.h>
  5#include <linux/zalloc.h>
  6#include <linux/err.h>
  7#include <sys/types.h>
  8#include <sys/stat.h>
  9#include <errno.h>
 10#include <fcntl.h>
 11#include <unistd.h>
 12#include <string.h>
 13#include <asm/bug.h>
 14#include <dirent.h>
 15
 16#include "data.h"
 17#include "util.h" // rm_rf_perf_data()
 18#include "debug.h"
 19#include "header.h"
 20#include "rlimit.h"
 21#include <internal/lib.h>
 22
 23static void close_dir(struct perf_data_file *files, int nr)
 24{
 25	while (--nr >= 0) {
 26		close(files[nr].fd);
 27		zfree(&files[nr].path);
 28	}
 29	free(files);
 30}
 31
 32void perf_data__close_dir(struct perf_data *data)
 33{
 34	close_dir(data->dir.files, data->dir.nr);
 35}
 36
 37int perf_data__create_dir(struct perf_data *data, int nr)
 38{
 39	enum rlimit_action set_rlimit = NO_CHANGE;
 40	struct perf_data_file *files = NULL;
 41	int i, ret;
 42
 43	if (WARN_ON(!data->is_dir))
 44		return -EINVAL;
 45
 46	files = zalloc(nr * sizeof(*files));
 47	if (!files)
 48		return -ENOMEM;
 49
 50	for (i = 0; i < nr; i++) {
 51		struct perf_data_file *file = &files[i];
 52
 53		ret = asprintf(&file->path, "%s/data.%d", data->path, i);
 54		if (ret < 0) {
 55			ret = -ENOMEM;
 56			goto out_err;
 57		}
 58
 59retry_open:
 60		ret = open(file->path, O_RDWR|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR);
 61		if (ret < 0) {
 62			/*
 63			 * If using parallel threads to collect data,
 64			 * perf record needs at least 6 fds per CPU.
 65			 * When we run out of them try to increase the limits.
 66			 */
 67			if (errno == EMFILE && rlimit__increase_nofile(&set_rlimit))
 68				goto retry_open;
 69
 70			ret = -errno;
 71			goto out_err;
 72		}
 73		set_rlimit = NO_CHANGE;
 74
 75		file->fd = ret;
 76	}
 77
 78	data->dir.version = PERF_DIR_VERSION;
 79	data->dir.files   = files;
 80	data->dir.nr      = nr;
 81	return 0;
 82
 83out_err:
 84	close_dir(files, i);
 85	return ret;
 86}
 87
 88int perf_data__open_dir(struct perf_data *data)
 89{
 90	struct perf_data_file *files = NULL;
 91	struct dirent *dent;
 92	int ret = -1;
 93	DIR *dir;
 94	int nr = 0;
 95
 96	/*
 97	 * Directory containing a single regular perf data file which is already
 98	 * open, means there is nothing more to do here.
 99	 */
100	if (perf_data__is_single_file(data))
101		return 0;
102
103	if (WARN_ON(!data->is_dir))
104		return -EINVAL;
105
106	/* The version is provided by DIR_FORMAT feature. */
107	if (WARN_ON(data->dir.version != PERF_DIR_VERSION))
108		return -1;
109
110	dir = opendir(data->path);
111	if (!dir)
112		return -EINVAL;
113
114	while ((dent = readdir(dir)) != NULL) {
115		struct perf_data_file *file;
116		char path[PATH_MAX];
117		struct stat st;
118
119		snprintf(path, sizeof(path), "%s/%s", data->path, dent->d_name);
120		if (stat(path, &st))
121			continue;
122
123		if (!S_ISREG(st.st_mode) || strncmp(dent->d_name, "data.", 5))
124			continue;
125
126		ret = -ENOMEM;
127
128		file = realloc(files, (nr + 1) * sizeof(*files));
129		if (!file)
130			goto out_err;
131
132		files = file;
133		file = &files[nr++];
134
135		file->path = strdup(path);
136		if (!file->path)
137			goto out_err;
138
139		ret = open(file->path, O_RDONLY);
140		if (ret < 0)
141			goto out_err;
142
143		file->fd = ret;
144		file->size = st.st_size;
145	}
146
147	closedir(dir);
148	if (!files)
149		return -EINVAL;
150
151	data->dir.files = files;
152	data->dir.nr    = nr;
153	return 0;
154
155out_err:
156	closedir(dir);
157	close_dir(files, nr);
158	return ret;
159}
160
161static bool check_pipe(struct perf_data *data)
162{
163	struct stat st;
164	bool is_pipe = false;
165	int fd = perf_data__is_read(data) ?
166		 STDIN_FILENO : STDOUT_FILENO;
167
168	if (!data->path) {
169		if (!fstat(fd, &st) && S_ISFIFO(st.st_mode))
170			is_pipe = true;
171	} else {
172		if (!strcmp(data->path, "-"))
173			is_pipe = true;
174	}
175
176	if (is_pipe) {
177		if (data->use_stdio) {
178			const char *mode;
179
180			mode = perf_data__is_read(data) ? "r" : "w";
181			data->file.fptr = fdopen(fd, mode);
182
183			if (data->file.fptr == NULL) {
184				data->file.fd = fd;
185				data->use_stdio = false;
186			}
187
188		/*
189		 * When is_pipe and data->file.fd is given, use given fd
190		 * instead of STDIN_FILENO or STDOUT_FILENO
191		 */
192		} else if (data->file.fd <= 0) {
193			data->file.fd = fd;
194		}
195	}
196
197	return data->is_pipe = is_pipe;
198}
199
200static int check_backup(struct perf_data *data)
201{
202	struct stat st;
203
204	if (perf_data__is_read(data))
205		return 0;
206
207	if (!stat(data->path, &st) && st.st_size) {
208		char oldname[PATH_MAX];
209		int ret;
210
211		snprintf(oldname, sizeof(oldname), "%s.old",
212			 data->path);
213
214		ret = rm_rf_perf_data(oldname);
215		if (ret) {
216			pr_err("Can't remove old data: %s (%s)\n",
217			       ret == -2 ?
218			       "Unknown file found" : strerror(errno),
219			       oldname);
220			return -1;
221		}
222
223		if (rename(data->path, oldname)) {
224			pr_err("Can't move data: %s (%s to %s)\n",
225			       strerror(errno),
226			       data->path, oldname);
227			return -1;
228		}
229	}
230
231	return 0;
232}
233
234static bool is_dir(struct perf_data *data)
235{
236	struct stat st;
237
238	if (stat(data->path, &st))
239		return false;
240
241	return (st.st_mode & S_IFMT) == S_IFDIR;
242}
243
244static int open_file_read(struct perf_data *data)
245{
246	int flags = data->in_place_update ? O_RDWR : O_RDONLY;
247	struct stat st;
248	int fd;
249	char sbuf[STRERR_BUFSIZE];
250
251	fd = open(data->file.path, flags);
252	if (fd < 0) {
253		int err = errno;
254
255		pr_err("failed to open %s: %s", data->file.path,
256			str_error_r(err, sbuf, sizeof(sbuf)));
257		if (err == ENOENT && !strcmp(data->file.path, "perf.data"))
258			pr_err("  (try 'perf record' first)");
259		pr_err("\n");
260		return -err;
261	}
262
263	if (fstat(fd, &st) < 0)
264		goto out_close;
265
266	if (!data->force && st.st_uid && (st.st_uid != geteuid())) {
267		pr_err("File %s not owned by current user or root (use -f to override)\n",
268		       data->file.path);
269		goto out_close;
270	}
271
272	if (!st.st_size) {
273		pr_info("zero-sized data (%s), nothing to do!\n",
274			data->file.path);
275		goto out_close;
276	}
277
278	data->file.size = st.st_size;
279	return fd;
280
281 out_close:
282	close(fd);
283	return -1;
284}
285
286static int open_file_write(struct perf_data *data)
287{
288	int fd;
289	char sbuf[STRERR_BUFSIZE];
290
291	fd = open(data->file.path, O_CREAT|O_RDWR|O_TRUNC|O_CLOEXEC,
292		  S_IRUSR|S_IWUSR);
293
294	if (fd < 0)
295		pr_err("failed to open %s : %s\n", data->file.path,
296			str_error_r(errno, sbuf, sizeof(sbuf)));
297
298	return fd;
299}
300
301static int open_file(struct perf_data *data)
302{
303	int fd;
304
305	fd = perf_data__is_read(data) ?
306	     open_file_read(data) : open_file_write(data);
307
308	if (fd < 0) {
309		zfree(&data->file.path);
310		return -1;
311	}
312
313	data->file.fd = fd;
314	return 0;
315}
316
317static int open_file_dup(struct perf_data *data)
318{
319	data->file.path = strdup(data->path);
320	if (!data->file.path)
321		return -ENOMEM;
322
323	return open_file(data);
324}
325
326static int open_dir(struct perf_data *data)
327{
328	int ret;
329
330	/*
331	 * So far we open only the header, so we can read the data version and
332	 * layout.
333	 */
334	if (asprintf(&data->file.path, "%s/data", data->path) < 0)
335		return -1;
336
337	if (perf_data__is_write(data) &&
338	    mkdir(data->path, S_IRWXU) < 0)
339		return -1;
340
341	ret = open_file(data);
342
343	/* Cleanup whatever we managed to create so far. */
344	if (ret && perf_data__is_write(data))
345		rm_rf_perf_data(data->path);
346
347	return ret;
348}
349
350int perf_data__open(struct perf_data *data)
351{
352	if (check_pipe(data))
353		return 0;
354
355	/* currently it allows stdio for pipe only */
356	data->use_stdio = false;
357
358	if (!data->path)
359		data->path = "perf.data";
360
361	if (check_backup(data))
362		return -1;
363
364	if (perf_data__is_read(data))
365		data->is_dir = is_dir(data);
366
367	return perf_data__is_dir(data) ?
368	       open_dir(data) : open_file_dup(data);
369}
370
371void perf_data__close(struct perf_data *data)
372{
373	if (perf_data__is_dir(data))
374		perf_data__close_dir(data);
375
376	zfree(&data->file.path);
377
378	if (data->use_stdio)
379		fclose(data->file.fptr);
380	else
381		close(data->file.fd);
382}
383
384ssize_t perf_data__read(struct perf_data *data, void *buf, size_t size)
385{
386	if (data->use_stdio) {
387		if (fread(buf, size, 1, data->file.fptr) == 1)
388			return size;
389		return feof(data->file.fptr) ? 0 : -1;
390	}
391	return readn(data->file.fd, buf, size);
392}
393
394ssize_t perf_data_file__write(struct perf_data_file *file,
395			      void *buf, size_t size)
396{
397	return writen(file->fd, buf, size);
398}
399
400ssize_t perf_data__write(struct perf_data *data,
401			 void *buf, size_t size)
402{
403	if (data->use_stdio) {
404		if (fwrite(buf, size, 1, data->file.fptr) == 1)
405			return size;
406		return -1;
407	}
408	return perf_data_file__write(&data->file, buf, size);
409}
410
411int perf_data__switch(struct perf_data *data,
412		      const char *postfix,
413		      size_t pos, bool at_exit,
414		      char **new_filepath)
415{
416	int ret;
417
418	if (perf_data__is_read(data))
419		return -EINVAL;
420
421	if (asprintf(new_filepath, "%s.%s", data->path, postfix) < 0)
422		return -ENOMEM;
423
424	/*
425	 * Only fire a warning, don't return error, continue fill
426	 * original file.
427	 */
428	if (rename(data->path, *new_filepath))
429		pr_warning("Failed to rename %s to %s\n", data->path, *new_filepath);
430
431	if (!at_exit) {
432		close(data->file.fd);
433		ret = perf_data__open(data);
434		if (ret < 0)
435			goto out;
436
437		if (lseek(data->file.fd, pos, SEEK_SET) == (off_t)-1) {
438			ret = -errno;
439			pr_debug("Failed to lseek to %zu: %s",
440				 pos, strerror(errno));
441			goto out;
442		}
443	}
444	ret = data->file.fd;
445out:
446	return ret;
447}
448
449unsigned long perf_data__size(struct perf_data *data)
450{
451	u64 size = data->file.size;
452	int i;
453
454	if (perf_data__is_single_file(data))
455		return size;
456
457	for (i = 0; i < data->dir.nr; i++) {
458		struct perf_data_file *file = &data->dir.files[i];
459
460		size += file->size;
461	}
462
463	return size;
464}
465
466int perf_data__make_kcore_dir(struct perf_data *data, char *buf, size_t buf_sz)
467{
468	int ret;
469
470	if (!data->is_dir)
471		return -1;
472
473	ret = snprintf(buf, buf_sz, "%s/kcore_dir", data->path);
474	if (ret < 0 || (size_t)ret >= buf_sz)
475		return -1;
476
477	return mkdir(buf, S_IRWXU);
478}
479
480bool has_kcore_dir(const char *path)
481{
482	struct dirent *d = ERR_PTR(-EINVAL);
483	const char *name = "kcore_dir";
484	DIR *dir = opendir(path);
485	size_t n = strlen(name);
486	bool result = false;
487
488	if (dir) {
489		while (d && !result) {
490			d = readdir(dir);
491			result = d ? strncmp(d->d_name, name, n) : false;
492		}
493		closedir(dir);
494	}
495
496	return result;
497}
498
499char *perf_data__kallsyms_name(struct perf_data *data)
500{
501	char *kallsyms_name;
502	struct stat st;
503
504	if (!data->is_dir)
505		return NULL;
506
507	if (asprintf(&kallsyms_name, "%s/kcore_dir/kallsyms", data->path) < 0)
508		return NULL;
509
510	if (stat(kallsyms_name, &st)) {
511		free(kallsyms_name);
512		return NULL;
513	}
514
515	return kallsyms_name;
516}
517
518char *perf_data__guest_kallsyms_name(struct perf_data *data, pid_t machine_pid)
519{
520	char *kallsyms_name;
521	struct stat st;
522
523	if (!data->is_dir)
524		return NULL;
525
526	if (asprintf(&kallsyms_name, "%s/kcore_dir__%d/kallsyms", data->path, machine_pid) < 0)
527		return NULL;
528
529	if (stat(kallsyms_name, &st)) {
530		free(kallsyms_name);
531		return NULL;
532	}
533
534	return kallsyms_name;
535}
536
537bool is_perf_data(const char *path)
538{
539	bool ret = false;
540	FILE *file;
541	u64 magic;
542
543	file = fopen(path, "r");
544	if (!file)
545		return false;
546
547	if (fread(&magic, 1, 8, file) < 8)
548		goto out;
549
550	ret = is_perf_magic(magic);
551out:
552	fclose(file);
553	return ret;
554}