Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1#include <linux/compiler.h>
2#include <linux/kernel.h>
3#include <sys/types.h>
4#include <sys/stat.h>
5#include <unistd.h>
6#include <string.h>
7
8#include "data.h"
9#include "util.h"
10
11static bool check_pipe(struct perf_data_file *file)
12{
13 struct stat st;
14 bool is_pipe = false;
15 int fd = perf_data_file__is_read(file) ?
16 STDIN_FILENO : STDOUT_FILENO;
17
18 if (!file->path) {
19 if (!fstat(fd, &st) && S_ISFIFO(st.st_mode))
20 is_pipe = true;
21 } else {
22 if (!strcmp(file->path, "-"))
23 is_pipe = true;
24 }
25
26 if (is_pipe)
27 file->fd = fd;
28
29 return file->is_pipe = is_pipe;
30}
31
32static int check_backup(struct perf_data_file *file)
33{
34 struct stat st;
35
36 if (!stat(file->path, &st) && st.st_size) {
37 /* TODO check errors properly */
38 char oldname[PATH_MAX];
39 snprintf(oldname, sizeof(oldname), "%s.old",
40 file->path);
41 unlink(oldname);
42 rename(file->path, oldname);
43 }
44
45 return 0;
46}
47
48static int open_file_read(struct perf_data_file *file)
49{
50 struct stat st;
51 int fd;
52
53 fd = open(file->path, O_RDONLY);
54 if (fd < 0) {
55 int err = errno;
56
57 pr_err("failed to open %s: %s", file->path, strerror(err));
58 if (err == ENOENT && !strcmp(file->path, "perf.data"))
59 pr_err(" (try 'perf record' first)");
60 pr_err("\n");
61 return -err;
62 }
63
64 if (fstat(fd, &st) < 0)
65 goto out_close;
66
67 if (!file->force && st.st_uid && (st.st_uid != geteuid())) {
68 pr_err("file %s not owned by current user or root\n",
69 file->path);
70 goto out_close;
71 }
72
73 if (!st.st_size) {
74 pr_info("zero-sized file (%s), nothing to do!\n",
75 file->path);
76 goto out_close;
77 }
78
79 file->size = st.st_size;
80 return fd;
81
82 out_close:
83 close(fd);
84 return -1;
85}
86
87static int open_file_write(struct perf_data_file *file)
88{
89 if (check_backup(file))
90 return -1;
91
92 return open(file->path, O_CREAT|O_RDWR|O_TRUNC, S_IRUSR|S_IWUSR);
93}
94
95static int open_file(struct perf_data_file *file)
96{
97 int fd;
98
99 fd = perf_data_file__is_read(file) ?
100 open_file_read(file) : open_file_write(file);
101
102 file->fd = fd;
103 return fd < 0 ? -1 : 0;
104}
105
106int perf_data_file__open(struct perf_data_file *file)
107{
108 if (check_pipe(file))
109 return 0;
110
111 if (!file->path)
112 file->path = "perf.data";
113
114 return open_file(file);
115}
116
117void perf_data_file__close(struct perf_data_file *file)
118{
119 close(file->fd);
120}