xref: /kernel/linux/linux-6.6/tools/perf/util/data.c (revision 62306a36) 
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 <internal/lib.h>
21
22static void close_dir(struct perf_data_file *files, int nr)
23{
24	while (--nr >= 0) {
25		close(files[nr].fd);
26		zfree(&files[nr].path);
27	}
28	free(files);
29}
30
31void perf_data__close_dir(struct perf_data *data)
32{
33	close_dir(data->dir.files, data->dir.nr);
34}
35
36int perf_data__create_dir(struct perf_data *data, int nr)
37{
38	struct perf_data_file *files = NULL;
39	int i, ret;
40
41	if (WARN_ON(!data->is_dir))
42		return -EINVAL;
43
44	files = zalloc(nr * sizeof(*files));
45	if (!files)
46		return -ENOMEM;
47
48	for (i = 0; i < nr; i++) {
49		struct perf_data_file *file = &files[i];
50
51		ret = asprintf(&file->path, "%s/data.%d", data->path, i);
52		if (ret < 0) {
53			ret = -ENOMEM;
54			goto out_err;
55		}
56
57		ret = open(file->path, O_RDWR|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR);
58		if (ret < 0) {
59			ret = -errno;
60			goto out_err;
61		}
62
63		file->fd = ret;
64	}
65
66	data->dir.version = PERF_DIR_VERSION;
67	data->dir.files   = files;
68	data->dir.nr      = nr;
69	return 0;
70
71out_err:
72	close_dir(files, i);
73	return ret;
74}
75
76int perf_data__open_dir(struct perf_data *data)
77{
78	struct perf_data_file *files = NULL;
79	struct dirent *dent;
80	int ret = -1;
81	DIR *dir;
82	int nr = 0;
83
84	/*
85	 * Directory containing a single regular perf data file which is already
86	 * open, means there is nothing more to do here.
87	 */
88	if (perf_data__is_single_file(data))
89		return 0;
90
91	if (WARN_ON(!data->is_dir))
92		return -EINVAL;
93
94	/* The version is provided by DIR_FORMAT feature. */
95	if (WARN_ON(data->dir.version != PERF_DIR_VERSION))
96		return -1;
97
98	dir = opendir(data->path);
99	if (!dir)
100		return -EINVAL;
101
102	while ((dent = readdir(dir)) != NULL) {
103		struct perf_data_file *file;
104		char path[PATH_MAX];
105		struct stat st;
106
107		snprintf(path, sizeof(path), "%s/%s", data->path, dent->d_name);
108		if (stat(path, &st))
109			continue;
110
111		if (!S_ISREG(st.st_mode) || strncmp(dent->d_name, "data.", 5))
112			continue;
113
114		ret = -ENOMEM;
115
116		file = realloc(files, (nr + 1) * sizeof(*files));
117		if (!file)
118			goto out_err;
119
120		files = file;
121		file = &files[nr++];
122
123		file->path = strdup(path);
124		if (!file->path)
125			goto out_err;
126
127		ret = open(file->path, O_RDONLY);
128		if (ret < 0)
129			goto out_err;
130
131		file->fd = ret;
132		file->size = st.st_size;
133	}
134
135	closedir(dir);
136	if (!files)
137		return -EINVAL;
138
139	data->dir.files = files;
140	data->dir.nr    = nr;
141	return 0;
142
143out_err:
144	closedir(dir);
145	close_dir(files, nr);
146	return ret;
147}
148
149int perf_data__update_dir(struct perf_data *data)
150{
151	int i;
152
153	if (WARN_ON(!data->is_dir))
154		return -EINVAL;
155
156	for (i = 0; i < data->dir.nr; i++) {
157		struct perf_data_file *file = &data->dir.files[i];
158		struct stat st;
159
160		if (fstat(file->fd, &st))
161			return -1;
162
163		file->size = st.st_size;
164	}
165
166	return 0;
167}
168
169static bool check_pipe(struct perf_data *data)
170{
171	struct stat st;
172	bool is_pipe = false;
173	int fd = perf_data__is_read(data) ?
174		 STDIN_FILENO : STDOUT_FILENO;
175
176	if (!data->path) {
177		if (!fstat(fd, &st) && S_ISFIFO(st.st_mode))
178			is_pipe = true;
179	} else {
180		if (!strcmp(data->path, "-"))
181			is_pipe = true;
182	}
183
184	if (is_pipe) {
185		if (data->use_stdio) {
186			const char *mode;
187
188			mode = perf_data__is_read(data) ? "r" : "w";
189			data->file.fptr = fdopen(fd, mode);
190
191			if (data->file.fptr == NULL) {
192				data->file.fd = fd;
193				data->use_stdio = false;
194			}
195		} else {
196			data->file.fd = fd;
197		}
198	}
199
200	return data->is_pipe = is_pipe;
201}
202
203static int check_backup(struct perf_data *data)
204{
205	struct stat st;
206
207	if (perf_data__is_read(data))
208		return 0;
209
210	if (!stat(data->path, &st) && st.st_size) {
211		char oldname[PATH_MAX];
212		int ret;
213
214		snprintf(oldname, sizeof(oldname), "%s.old",
215			 data->path);
216
217		ret = rm_rf_perf_data(oldname);
218		if (ret) {
219			pr_err("Can't remove old data: %s (%s)\n",
220			       ret == -2 ?
221			       "Unknown file found" : strerror(errno),
222			       oldname);
223			return -1;
224		}
225
226		if (rename(data->path, oldname)) {
227			pr_err("Can't move data: %s (%s to %s)\n",
228			       strerror(errno),
229			       data->path, oldname);
230			return -1;
231		}
232	}
233
234	return 0;
235}
236
237static bool is_dir(struct perf_data *data)
238{
239	struct stat st;
240
241	if (stat(data->path, &st))
242		return false;
243
244	return (st.st_mode & S_IFMT) == S_IFDIR;
245}
246
247static int open_file_read(struct perf_data *data)
248{
249	int flags = data->in_place_update ? O_RDWR : O_RDONLY;
250	struct stat st;
251	int fd;
252	char sbuf[STRERR_BUFSIZE];
253
254	fd = open(data->file.path, flags);
255	if (fd < 0) {
256		int err = errno;
257
258		pr_err("failed to open %s: %s", data->file.path,
259			str_error_r(err, sbuf, sizeof(sbuf)));
260		if (err == ENOENT && !strcmp(data->file.path, "perf.data"))
261			pr_err("  (try 'perf record' first)");
262		pr_err("\n");
263		return -err;
264	}
265
266	if (fstat(fd, &st) < 0)
267		goto out_close;
268
269	if (!data->force && st.st_uid && (st.st_uid != geteuid())) {
270		pr_err("File %s not owned by current user or root (use -f to override)\n",
271		       data->file.path);
272		goto out_close;
273	}
274
275	if (!st.st_size) {
276		pr_info("zero-sized data (%s), nothing to do!\n",
277			data->file.path);
278		goto out_close;
279	}
280
281	data->file.size = st.st_size;
282	return fd;
283
284 out_close:
285	close(fd);
286	return -1;
287}
288
289static int open_file_write(struct perf_data *data)
290{
291	int fd;
292	char sbuf[STRERR_BUFSIZE];
293
294	fd = open(data->file.path, O_CREAT|O_RDWR|O_TRUNC|O_CLOEXEC,
295		  S_IRUSR|S_IWUSR);
296
297	if (fd < 0)
298		pr_err("failed to open %s : %s\n", data->file.path,
299			str_error_r(errno, sbuf, sizeof(sbuf)));
300
301	return fd;
302}
303
304static int open_file(struct perf_data *data)
305{
306	int fd;
307
308	fd = perf_data__is_read(data) ?
309	     open_file_read(data) : open_file_write(data);
310
311	if (fd < 0) {
312		zfree(&data->file.path);
313		return -1;
314	}
315
316	data->file.fd = fd;
317	return 0;
318}
319
320static int open_file_dup(struct perf_data *data)
321{
322	data->file.path = strdup(data->path);
323	if (!data->file.path)
324		return -ENOMEM;
325
326	return open_file(data);
327}
328
329static int open_dir(struct perf_data *data)
330{
331	int ret;
332
333	/*
334	 * So far we open only the header, so we can read the data version and
335	 * layout.
336	 */
337	if (asprintf(&data->file.path, "%s/data", data->path) < 0)
338		return -1;
339
340	if (perf_data__is_write(data) &&
341	    mkdir(data->path, S_IRWXU) < 0)
342		return -1;
343
344	ret = open_file(data);
345
346	/* Cleanup whatever we managed to create so far. */
347	if (ret && perf_data__is_write(data))
348		rm_rf_perf_data(data->path);
349
350	return ret;
351}
352
353int perf_data__open(struct perf_data *data)
354{
355	if (check_pipe(data))
356		return 0;
357
358	/* currently it allows stdio for pipe only */
359	data->use_stdio = false;
360
361	if (!data->path)
362		data->path = "perf.data";
363
364	if (check_backup(data))
365		return -1;
366
367	if (perf_data__is_read(data))
368		data->is_dir = is_dir(data);
369
370	return perf_data__is_dir(data) ?
371	       open_dir(data) : open_file_dup(data);
372}
373
374void perf_data__close(struct perf_data *data)
375{
376	if (perf_data__is_dir(data))
377		perf_data__close_dir(data);
378
379	zfree(&data->file.path);
380
381	if (data->use_stdio)
382		fclose(data->file.fptr);
383	else
384		close(data->file.fd);
385}
386
387ssize_t perf_data__read(struct perf_data *data, void *buf, size_t size)
388{
389	if (data->use_stdio) {
390		if (fread(buf, size, 1, data->file.fptr) == 1)
391			return size;
392		return feof(data->file.fptr) ? 0 : -1;
393	}
394	return readn(data->file.fd, buf, size);
395}
396
397ssize_t perf_data_file__write(struct perf_data_file *file,
398			      void *buf, size_t size)
399{
400	return writen(file->fd, buf, size);
401}
402
403ssize_t perf_data__write(struct perf_data *data,
404			      void *buf, size_t size)
405{
406	if (data->use_stdio) {
407		if (fwrite(buf, size, 1, data->file.fptr) == 1)
408			return size;
409		return -1;
410	}
411	return perf_data_file__write(&data->file, buf, size);
412}
413
414int perf_data__switch(struct perf_data *data,
415			   const char *postfix,
416			   size_t pos, bool at_exit,
417			   char **new_filepath)
418{
419	int ret;
420
421	if (perf_data__is_read(data))
422		return -EINVAL;
423
424	if (asprintf(new_filepath, "%s.%s", data->path, postfix) < 0)
425		return -ENOMEM;
426
427	/*
428	 * Only fire a warning, don't return error, continue fill
429	 * original file.
430	 */
431	if (rename(data->path, *new_filepath))
432		pr_warning("Failed to rename %s to %s\n", data->path, *new_filepath);
433
434	if (!at_exit) {
435		close(data->file.fd);
436		ret = perf_data__open(data);
437		if (ret < 0)
438			goto out;
439
440		if (lseek(data->file.fd, pos, SEEK_SET) == (off_t)-1) {
441			ret = -errno;
442			pr_debug("Failed to lseek to %zu: %s",
443				 pos, strerror(errno));
444			goto out;
445		}
446	}
447	ret = data->file.fd;
448out:
449	return ret;
450}
451
452unsigned long perf_data__size(struct perf_data *data)
453{
454	u64 size = data->file.size;
455	int i;
456
457	if (perf_data__is_single_file(data))
458		return size;
459
460	for (i = 0; i < data->dir.nr; i++) {
461		struct perf_data_file *file = &data->dir.files[i];
462
463		size += file->size;
464	}
465
466	return size;
467}
468
469int perf_data__make_kcore_dir(struct perf_data *data, char *buf, size_t buf_sz)
470{
471	int ret;
472
473	if (!data->is_dir)
474		return -1;
475
476	ret = snprintf(buf, buf_sz, "%s/kcore_dir", data->path);
477	if (ret < 0 || (size_t)ret >= buf_sz)
478		return -1;
479
480	return mkdir(buf, S_IRWXU);
481}
482
483bool has_kcore_dir(const char *path)
484{
485	struct dirent *d = ERR_PTR(-EINVAL);
486	const char *name = "kcore_dir";
487	DIR *dir = opendir(path);
488	size_t n = strlen(name);
489	bool result = false;
490
491	if (dir) {
492		while (d && !result) {
493			d = readdir(dir);
494			result = d ? strncmp(d->d_name, name, n) : false;
495		}
496		closedir(dir);
497	}
498
499	return result;
500}
501
502char *perf_data__kallsyms_name(struct perf_data *data)
503{
504	char *kallsyms_name;
505	struct stat st;
506
507	if (!data->is_dir)
508		return NULL;
509
510	if (asprintf(&kallsyms_name, "%s/kcore_dir/kallsyms", data->path) < 0)
511		return NULL;
512
513	if (stat(kallsyms_name, &st)) {
514		free(kallsyms_name);
515		return NULL;
516	}
517
518	return kallsyms_name;
519}
520
521char *perf_data__guest_kallsyms_name(struct perf_data *data, pid_t machine_pid)
522{
523	char *kallsyms_name;
524	struct stat st;
525
526	if (!data->is_dir)
527		return NULL;
528
529	if (asprintf(&kallsyms_name, "%s/kcore_dir__%d/kallsyms", data->path, machine_pid) < 0)
530		return NULL;
531
532	if (stat(kallsyms_name, &st)) {
533		free(kallsyms_name);
534		return NULL;
535	}
536
537	return kallsyms_name;
538}
539
540bool is_perf_data(const char *path)
541{
542	bool ret = false;
543	FILE *file;
544	u64 magic;
545
546	file = fopen(path, "r");
547	if (!file)
548		return false;
549
550	if (fread(&magic, 1, 8, file) < 8)
551		goto out;
552
553	ret = is_perf_magic(magic);
554out:
555	fclose(file);
556	return ret;
557}
558