summaryrefslogtreecommitdiff
path: root/tools/perf/util/data.c
blob: 79192758bdb3de9d232de2f576edc8b0d6bcffde (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
// SPDX-License-Identifier: GPL-2.0
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>

#include "data.h"
#include "util.h"
#include "debug.h"

#ifndef O_CLOEXEC
#ifdef __sparc__
#define O_CLOEXEC	0x400000
#elif defined(__alpha__) || defined(__hppa__)
#define O_CLOEXEC	010000000
#else
#define O_CLOEXEC	02000000
#endif
#endif

static bool check_pipe(struct perf_data_file *file)
{
	struct stat st;
	bool is_pipe = false;
	int fd = perf_data_file__is_read(file) ?
		 STDIN_FILENO : STDOUT_FILENO;

	if (!file->path) {
		if (!fstat(fd, &st) && S_ISFIFO(st.st_mode))
			is_pipe = true;
	} else {
		if (!strcmp(file->path, "-"))
			is_pipe = true;
	}

	if (is_pipe)
		file->fd = fd;

	return file->is_pipe = is_pipe;
}

static int check_backup(struct perf_data_file *file)
{
	struct stat st;

	if (!stat(file->path, &st) && st.st_size) {
		/* TODO check errors properly */
		char oldname[PATH_MAX];
		snprintf(oldname, sizeof(oldname), "%s.old",
			 file->path);
		unlink(oldname);
		rename(file->path, oldname);
	}

	return 0;
}

static int open_file_read(struct perf_data_file *file)
{
	struct stat st;
	int fd;
	char sbuf[STRERR_BUFSIZE];

	fd = open(file->path, O_RDONLY);
	if (fd < 0) {
		int err = errno;

		pr_err("failed to open %s: %s", file->path,
			str_error_r(err, sbuf, sizeof(sbuf)));
		if (err == ENOENT && !strcmp(file->path, "perf.data"))
			pr_err("  (try 'perf record' first)");
		pr_err("\n");
		return -err;
	}

	if (fstat(fd, &st) < 0)
		goto out_close;

	if (!file->force && st.st_uid && (st.st_uid != geteuid())) {
		pr_err("File %s not owned by current user or root (use -f to override)\n",
		       file->path);
		goto out_close;
	}

	if (!st.st_size) {
		pr_info("zero-sized file (%s), nothing to do!\n",
			file->path);
		goto out_close;
	}

	file->size = st.st_size;
	return fd;

 out_close:
	close(fd);
	return -1;
}

static int open_file_write(struct perf_data_file *file)
{
	int fd;
	char sbuf[STRERR_BUFSIZE];

	if (check_backup(file))
		return -1;

	fd = open(file->path, O_CREAT|O_RDWR|O_TRUNC|O_CLOEXEC,
		  S_IRUSR|S_IWUSR);

	if (fd < 0)
		pr_err("failed to open %s : %s\n", file->path,
			str_error_r(errno, sbuf, sizeof(sbuf)));

	return fd;
}

static int open_file(struct perf_data_file *file)
{
	int fd;

	fd = perf_data_file__is_read(file) ?
	     open_file_read(file) : open_file_write(file);

	file->fd = fd;
	return fd < 0 ? -1 : 0;
}

int perf_data_file__open(struct perf_data_file *file)
{
	if (check_pipe(file))
		return 0;

	if (!file->path)
		file->path = "perf.data";

	return open_file(file);
}

void perf_data_file__close(struct perf_data_file *file)
{
	close(file->fd);
}

ssize_t perf_data_file__write(struct perf_data_file *file,
			      void *buf, size_t size)
{
	return writen(file->fd, buf, size);
}

int perf_data_file__switch(struct perf_data_file *file,
			   const char *postfix,
			   size_t pos, bool at_exit)
{
	char *new_filepath;
	int ret;

	if (check_pipe(file))
		return -EINVAL;
	if (perf_data_file__is_read(file))
		return -EINVAL;

	if (asprintf(&new_filepath, "%s.%s", file->path, postfix) < 0)
		return -ENOMEM;

	/*
	 * Only fire a warning, don't return error, continue fill
	 * original file.
	 */
	if (rename(file->path, new_filepath))
		pr_warning("Failed to rename %s to %s\n", file->path, new_filepath);

	if (!at_exit) {
		close(file->fd);
		ret = perf_data_file__open(file);
		if (ret < 0)
			goto out;

		if (lseek(file->fd, pos, SEEK_SET) == (off_t)-1) {
			ret = -errno;
			pr_debug("Failed to lseek to %zu: %s",
				 pos, strerror(errno));
			goto out;
		}
	}
	ret = file->fd;
out:
	free(new_filepath);
	return ret;
}