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
161int perf_data__update_dir(struct perf_data *data)
162{
163	int i;
164
165	if (WARN_ON(!data->is_dir))
166		return -EINVAL;
167
168	for (i = 0; i < data->dir.nr; i++) {
169		struct perf_data_file *file = &data->dir.files[i];
170		struct stat st;
171
172		if (fstat(file->fd, &st))
173			return -1;
174
175		file->size = st.st_size;
176	}
177
178	return 0;
179}
180
181static bool check_pipe(struct perf_data *data)
182{
183	struct stat st;
184	bool is_pipe = false;
185	int fd = perf_data__is_read(data) ?
186		 STDIN_FILENO : STDOUT_FILENO;
187
188	if (!data->path) {
189		if (!fstat(fd, &st) && S_ISFIFO(st.st_mode))
190			is_pipe = true;
191	} else {
192		if (!strcmp(data->path, "-"))
193			is_pipe = true;
194	}
195
196	if (is_pipe) {
197		if (data->use_stdio) {
198			const char *mode;
199
200			mode = perf_data__is_read(data) ? "r" : "w";
201			data->file.fptr = fdopen(fd, mode);
202
203			if (data->file.fptr == NULL) {
204				data->file.fd = fd;
205				data->use_stdio = false;
206			}
207		} else {
208			data->file.fd = fd;
209		}
210	}
211
212	return data->is_pipe = is_pipe;
213}
214
215static int check_backup(struct perf_data *data)
216{
217	struct stat st;
218
219	if (perf_data__is_read(data))
220		return 0;
221
222	if (!stat(data->path, &st) && st.st_size) {
223		char oldname[PATH_MAX];
224		int ret;
225
226		snprintf(oldname, sizeof(oldname), "%s.old",
227			 data->path);
228
229		ret = rm_rf_perf_data(oldname);
230		if (ret) {
231			pr_err("Can't remove old data: %s (%s)\n",
232			       ret == -2 ?
233			       "Unknown file found" : strerror(errno),
234			       oldname);
235			return -1;
236		}
237
238		if (rename(data->path, oldname)) {
239			pr_err("Can't move data: %s (%s to %s)\n",
240			       strerror(errno),
241			       data->path, oldname);
242			return -1;
243		}
244	}
245
246	return 0;
247}
248
249static bool is_dir(struct perf_data *data)
250{
251	struct stat st;
252
253	if (stat(data->path, &st))
254		return false;
255
256	return (st.st_mode & S_IFMT) == S_IFDIR;
257}
258
259static int open_file_read(struct perf_data *data)
260{
261	int flags = data->in_place_update ? O_RDWR : O_RDONLY;
262	struct stat st;
263	int fd;
264	char sbuf[STRERR_BUFSIZE];
265
266	fd = open(data->file.path, flags);
267	if (fd < 0) {
268		int err = errno;
269
270		pr_err("failed to open %s: %s", data->file.path,
271			str_error_r(err, sbuf, sizeof(sbuf)));
272		if (err == ENOENT && !strcmp(data->file.path, "perf.data"))
273			pr_err("  (try 'perf record' first)");
274		pr_err("\n");
275		return -err;
276	}
277
278	if (fstat(fd, &st) < 0)
279		goto out_close;
280
281	if (!data->force && st.st_uid && (st.st_uid != geteuid())) {
282		pr_err("File %s not owned by current user or root (use -f to override)\n",
283		       data->file.path);
284		goto out_close;
285	}
286
287	if (!st.st_size) {
288		pr_info("zero-sized data (%s), nothing to do!\n",
289			data->file.path);
290		goto out_close;
291	}
292
293	data->file.size = st.st_size;
294	return fd;
295
296 out_close:
297	close(fd);
298	return -1;
299}
300
301static int open_file_write(struct perf_data *data)
302{
303	int fd;
304	char sbuf[STRERR_BUFSIZE];
305
306	fd = open(data->file.path, O_CREAT|O_RDWR|O_TRUNC|O_CLOEXEC,
307		  S_IRUSR|S_IWUSR);
308
309	if (fd < 0)
310		pr_err("failed to open %s : %s\n", data->file.path,
311			str_error_r(errno, sbuf, sizeof(sbuf)));
312
313	return fd;
314}
315
316static int open_file(struct perf_data *data)
317{
318	int fd;
319
320	fd = perf_data__is_read(data) ?
321	     open_file_read(data) : open_file_write(data);
322
323	if (fd < 0) {
324		zfree(&data->file.path);
325		return -1;
326	}
327
328	data->file.fd = fd;
329	return 0;
330}
331
332static int open_file_dup(struct perf_data *data)
333{
334	data->file.path = strdup(data->path);
335	if (!data->file.path)
336		return -ENOMEM;
337
338	return open_file(data);
339}
340
341static int open_dir(struct perf_data *data)
342{
343	int ret;
344
345	/*
346	 * So far we open only the header, so we can read the data version and
347	 * layout.
348	 */
349	if (asprintf(&data->file.path, "%s/data", data->path) < 0)
350		return -1;
351
352	if (perf_data__is_write(data) &&
353	    mkdir(data->path, S_IRWXU) < 0)
354		return -1;
355
356	ret = open_file(data);
357
358	/* Cleanup whatever we managed to create so far. */
359	if (ret && perf_data__is_write(data))
360		rm_rf_perf_data(data->path);
361
362	return ret;
363}
364
365int perf_data__open(struct perf_data *data)
366{
367	if (check_pipe(data))
368		return 0;
369
370	/* currently it allows stdio for pipe only */
371	data->use_stdio = false;
372
373	if (!data->path)
374		data->path = "perf.data";
375
376	if (check_backup(data))
377		return -1;
378
379	if (perf_data__is_read(data))
380		data->is_dir = is_dir(data);
381
382	return perf_data__is_dir(data) ?
383	       open_dir(data) : open_file_dup(data);
384}
385
386void perf_data__close(struct perf_data *data)
387{
388	if (perf_data__is_dir(data))
389		perf_data__close_dir(data);
390
391	zfree(&data->file.path);
392
393	if (data->use_stdio)
394		fclose(data->file.fptr);
395	else
396		close(data->file.fd);
397}
398
399ssize_t perf_data__read(struct perf_data *data, void *buf, size_t size)
400{
401	if (data->use_stdio) {
402		if (fread(buf, size, 1, data->file.fptr) == 1)
403			return size;
404		return feof(data->file.fptr) ? 0 : -1;
405	}
406	return readn(data->file.fd, buf, size);
407}
408
409ssize_t perf_data_file__write(struct perf_data_file *file,
410			      void *buf, size_t size)
411{
412	return writen(file->fd, buf, size);
413}
414
415ssize_t perf_data__write(struct perf_data *data,
416			 void *buf, size_t size)
417{
418	if (data->use_stdio) {
419		if (fwrite(buf, size, 1, data->file.fptr) == 1)
420			return size;
421		return -1;
422	}
423	return perf_data_file__write(&data->file, buf, size);
424}
425
426int perf_data__switch(struct perf_data *data,
427		      const char *postfix,
428		      size_t pos, bool at_exit,
429		      char **new_filepath)
430{
431	int ret;
432
433	if (perf_data__is_read(data))
434		return -EINVAL;
435
436	if (asprintf(new_filepath, "%s.%s", data->path, postfix) < 0)
437		return -ENOMEM;
438
439	/*
440	 * Only fire a warning, don't return error, continue fill
441	 * original file.
442	 */
443	if (rename(data->path, *new_filepath))
444		pr_warning("Failed to rename %s to %s\n", data->path, *new_filepath);
445
446	if (!at_exit) {
447		close(data->file.fd);
448		ret = perf_data__open(data);
449		if (ret < 0)
450			goto out;
451
452		if (lseek(data->file.fd, pos, SEEK_SET) == (off_t)-1) {
453			ret = -errno;
454			pr_debug("Failed to lseek to %zu: %s",
455				 pos, strerror(errno));
456			goto out;
457		}
458	}
459	ret = data->file.fd;
460out:
461	return ret;
462}
463
464unsigned long perf_data__size(struct perf_data *data)
465{
466	u64 size = data->file.size;
467	int i;
468
469	if (perf_data__is_single_file(data))
470		return size;
471
472	for (i = 0; i < data->dir.nr; i++) {
473		struct perf_data_file *file = &data->dir.files[i];
474
475		size += file->size;
476	}
477
478	return size;
479}
480
481int perf_data__make_kcore_dir(struct perf_data *data, char *buf, size_t buf_sz)
482{
483	int ret;
484
485	if (!data->is_dir)
486		return -1;
487
488	ret = snprintf(buf, buf_sz, "%s/kcore_dir", data->path);
489	if (ret < 0 || (size_t)ret >= buf_sz)
490		return -1;
491
492	return mkdir(buf, S_IRWXU);
493}
494
495bool has_kcore_dir(const char *path)
496{
497	struct dirent *d = ERR_PTR(-EINVAL);
498	const char *name = "kcore_dir";
499	DIR *dir = opendir(path);
500	size_t n = strlen(name);
501	bool result = false;
502
503	if (dir) {
504		while (d && !result) {
505			d = readdir(dir);
506			result = d ? strncmp(d->d_name, name, n) : false;
507		}
508		closedir(dir);
509	}
510
511	return result;
512}
513
514char *perf_data__kallsyms_name(struct perf_data *data)
515{
516	char *kallsyms_name;
517	struct stat st;
518
519	if (!data->is_dir)
520		return NULL;
521
522	if (asprintf(&kallsyms_name, "%s/kcore_dir/kallsyms", data->path) < 0)
523		return NULL;
524
525	if (stat(kallsyms_name, &st)) {
526		free(kallsyms_name);
527		return NULL;
528	}
529
530	return kallsyms_name;
531}
532
533char *perf_data__guest_kallsyms_name(struct perf_data *data, pid_t machine_pid)
534{
535	char *kallsyms_name;
536	struct stat st;
537
538	if (!data->is_dir)
539		return NULL;
540
541	if (asprintf(&kallsyms_name, "%s/kcore_dir__%d/kallsyms", data->path, machine_pid) < 0)
542		return NULL;
543
544	if (stat(kallsyms_name, &st)) {
545		free(kallsyms_name);
546		return NULL;
547	}
548
549	return kallsyms_name;
550}
551
552bool is_perf_data(const char *path)
553{
554	bool ret = false;
555	FILE *file;
556	u64 magic;
557
558	file = fopen(path, "r");
559	if (!file)
560		return false;
561
562	if (fread(&magic, 1, 8, file) < 8)
563		goto out;
564
565	ret = is_perf_magic(magic);
566out:
567	fclose(file);
568	return ret;
569}
570