1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/compiler.h>
3 #include <linux/kernel.h>
4 #include <sys/types.h>
5 #include <sys/stat.h>
6 #include <errno.h>
7 #include <fcntl.h>
8 #include <unistd.h>
9 #include <string.h>
10
11 #include "data.h"
12 #include "util.h"
13 #include "debug.h"
14
check_pipe(struct perf_data * data)15 static bool check_pipe(struct perf_data *data)
16 {
17 struct stat st;
18 bool is_pipe = false;
19 int fd = perf_data__is_read(data) ?
20 STDIN_FILENO : STDOUT_FILENO;
21
22 if (!data->file.path) {
23 if (!fstat(fd, &st) && S_ISFIFO(st.st_mode))
24 is_pipe = true;
25 } else {
26 if (!strcmp(data->file.path, "-"))
27 is_pipe = true;
28 }
29
30 if (is_pipe)
31 data->file.fd = fd;
32
33 return data->is_pipe = is_pipe;
34 }
35
check_backup(struct perf_data * data)36 static int check_backup(struct perf_data *data)
37 {
38 struct stat st;
39
40 if (!stat(data->file.path, &st) && st.st_size) {
41 /* TODO check errors properly */
42 char oldname[PATH_MAX];
43 snprintf(oldname, sizeof(oldname), "%s.old",
44 data->file.path);
45 unlink(oldname);
46 rename(data->file.path, oldname);
47 }
48
49 return 0;
50 }
51
open_file_read(struct perf_data * data)52 static int open_file_read(struct perf_data *data)
53 {
54 struct stat st;
55 int fd;
56 char sbuf[STRERR_BUFSIZE];
57
58 fd = open(data->file.path, O_RDONLY);
59 if (fd < 0) {
60 int err = errno;
61
62 pr_err("failed to open %s: %s", data->file.path,
63 str_error_r(err, sbuf, sizeof(sbuf)));
64 if (err == ENOENT && !strcmp(data->file.path, "perf.data"))
65 pr_err(" (try 'perf record' first)");
66 pr_err("\n");
67 return -err;
68 }
69
70 if (fstat(fd, &st) < 0)
71 goto out_close;
72
73 if (!data->force && st.st_uid && (st.st_uid != geteuid())) {
74 pr_err("File %s not owned by current user or root (use -f to override)\n",
75 data->file.path);
76 goto out_close;
77 }
78
79 if (!st.st_size) {
80 pr_info("zero-sized data (%s), nothing to do!\n",
81 data->file.path);
82 goto out_close;
83 }
84
85 data->size = st.st_size;
86 return fd;
87
88 out_close:
89 close(fd);
90 return -1;
91 }
92
open_file_write(struct perf_data * data)93 static int open_file_write(struct perf_data *data)
94 {
95 int fd;
96 char sbuf[STRERR_BUFSIZE];
97
98 if (check_backup(data))
99 return -1;
100
101 fd = open(data->file.path, O_CREAT|O_RDWR|O_TRUNC|O_CLOEXEC,
102 S_IRUSR|S_IWUSR);
103
104 if (fd < 0)
105 pr_err("failed to open %s : %s\n", data->file.path,
106 str_error_r(errno, sbuf, sizeof(sbuf)));
107
108 return fd;
109 }
110
open_file(struct perf_data * data)111 static int open_file(struct perf_data *data)
112 {
113 int fd;
114
115 fd = perf_data__is_read(data) ?
116 open_file_read(data) : open_file_write(data);
117
118 data->file.fd = fd;
119 return fd < 0 ? -1 : 0;
120 }
121
perf_data__open(struct perf_data * data)122 int perf_data__open(struct perf_data *data)
123 {
124 if (check_pipe(data))
125 return 0;
126
127 if (!data->file.path)
128 data->file.path = "perf.data";
129
130 return open_file(data);
131 }
132
perf_data__close(struct perf_data * data)133 void perf_data__close(struct perf_data *data)
134 {
135 close(data->file.fd);
136 }
137
perf_data_file__write(struct perf_data_file * file,void * buf,size_t size)138 ssize_t perf_data_file__write(struct perf_data_file *file,
139 void *buf, size_t size)
140 {
141 return writen(file->fd, buf, size);
142 }
143
perf_data__write(struct perf_data * data,void * buf,size_t size)144 ssize_t perf_data__write(struct perf_data *data,
145 void *buf, size_t size)
146 {
147 return perf_data_file__write(&data->file, buf, size);
148 }
149
perf_data__switch(struct perf_data * data,const char * postfix,size_t pos,bool at_exit)150 int perf_data__switch(struct perf_data *data,
151 const char *postfix,
152 size_t pos, bool at_exit)
153 {
154 char *new_filepath;
155 int ret;
156
157 if (check_pipe(data))
158 return -EINVAL;
159 if (perf_data__is_read(data))
160 return -EINVAL;
161
162 if (asprintf(&new_filepath, "%s.%s", data->file.path, postfix) < 0)
163 return -ENOMEM;
164
165 /*
166 * Only fire a warning, don't return error, continue fill
167 * original file.
168 */
169 if (rename(data->file.path, new_filepath))
170 pr_warning("Failed to rename %s to %s\n", data->file.path, new_filepath);
171
172 if (!at_exit) {
173 close(data->file.fd);
174 ret = perf_data__open(data);
175 if (ret < 0)
176 goto out;
177
178 if (lseek(data->file.fd, pos, SEEK_SET) == (off_t)-1) {
179 ret = -errno;
180 pr_debug("Failed to lseek to %zu: %s",
181 pos, strerror(errno));
182 goto out;
183 }
184 }
185 ret = data->file.fd;
186 out:
187 free(new_filepath);
188 return ret;
189 }
190
