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
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
|
/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "cutils"
/* These defines are only needed because prebuilt headers are out of date */
#define __USE_XOPEN2K8 1
#define _ATFILE_SOURCE 1
#define _GNU_SOURCE 1
#include <cutils/fs.h>
#include <cutils/log.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <limits.h>
#include <stdlib.h>
#include <dirent.h>
#define ALL_PERMS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
#define BUF_SIZE 64
int fs_prepare_dir(const char* path, mode_t mode, uid_t uid, gid_t gid) {
// Check if path needs to be created
struct stat sb;
if (TEMP_FAILURE_RETRY(lstat(path, &sb)) == -1) {
if (errno == ENOENT) {
goto create;
} else {
ALOGE("Failed to lstat(%s): %s", path, strerror(errno));
return -1;
}
}
// Exists, verify status
if (!S_ISDIR(sb.st_mode)) {
ALOGE("Not a directory: %s", path);
return -1;
}
if (((sb.st_mode & ALL_PERMS) == mode) && (sb.st_uid == uid) && (sb.st_gid == gid)) {
return 0;
} else {
goto fixup;
}
create:
if (TEMP_FAILURE_RETRY(mkdir(path, mode)) == -1) {
if (errno != EEXIST) {
ALOGE("Failed to mkdir(%s): %s", path, strerror(errno));
return -1;
}
}
fixup:
if (TEMP_FAILURE_RETRY(chmod(path, mode)) == -1) {
ALOGE("Failed to chmod(%s, %d): %s", path, mode, strerror(errno));
return -1;
}
if (TEMP_FAILURE_RETRY(chown(path, uid, gid)) == -1) {
ALOGE("Failed to chown(%s, %d, %d): %s", path, uid, gid, strerror(errno));
return -1;
}
return 0;
}
int fs_read_atomic_int(const char* path, int* out_value) {
int fd = TEMP_FAILURE_RETRY(open(path, O_RDONLY));
if (fd == -1) {
ALOGE("Failed to read %s: %s", path, strerror(errno));
return -1;
}
char buf[BUF_SIZE];
if (TEMP_FAILURE_RETRY(read(fd, buf, BUF_SIZE)) == -1) {
ALOGE("Failed to read %s: %s", path, strerror(errno));
goto fail;
}
if (sscanf(buf, "%d", out_value) != 1) {
ALOGE("Failed to parse %s: %s", path, strerror(errno));
goto fail;
}
close(fd);
return 0;
fail:
close(fd);
*out_value = -1;
return -1;
}
int fs_write_atomic_int(const char* path, int value) {
char temp[PATH_MAX];
if (snprintf(temp, PATH_MAX, "%s.XXXXXX", path) >= PATH_MAX) {
ALOGE("Path too long");
return -1;
}
int fd = TEMP_FAILURE_RETRY(mkstemp(temp));
if (fd == -1) {
ALOGE("Failed to open %s: %s", temp, strerror(errno));
return -1;
}
char buf[BUF_SIZE];
int len = snprintf(buf, BUF_SIZE, "%d", value) + 1;
if (len > BUF_SIZE) {
ALOGE("Value %d too large: %s", value, strerror(errno));
goto fail;
}
if (TEMP_FAILURE_RETRY(write(fd, buf, len)) < len) {
ALOGE("Failed to write %s: %s", temp, strerror(errno));
goto fail;
}
if (close(fd) == -1) {
ALOGE("Failed to close %s: %s", temp, strerror(errno));
goto fail_closed;
}
if (rename(temp, path) == -1) {
ALOGE("Failed to rename %s to %s: %s", temp, path, strerror(errno));
goto fail_closed;
}
return 0;
fail:
close(fd);
fail_closed:
unlink(temp);
return -1;
}
int fs_mkdirs(const char* path, mode_t mode) {
int res = 0;
int fd = 0;
struct stat sb;
char* buf = strdup(path);
if (*buf != '/') {
ALOGE("Relative paths are not allowed: %s", buf);
res = -EINVAL;
goto done;
}
if ((fd = open("/", 0)) == -1) {
ALOGE("Failed to open(/): %s", strerror(errno));
res = -errno;
goto done;
}
char* segment = buf + 1;
char* p = segment;
while (*p != '\0') {
if (*p == '/') {
*p = '\0';
if (!strcmp(segment, "..") || !strcmp(segment, ".") || !strcmp(segment, "")) {
ALOGE("Invalid path: %s", buf);
res = -EINVAL;
goto done_close;
}
if (fstatat(fd, segment, &sb, AT_SYMLINK_NOFOLLOW) != 0) {
if (errno == ENOENT) {
/* Nothing there yet; let's create it! */
if (mkdirat(fd, segment, mode) != 0) {
if (errno == EEXIST) {
/* We raced with someone; ignore */
} else {
ALOGE("Failed to mkdirat(%s): %s", buf, strerror(errno));
res = -errno;
goto done_close;
}
}
} else {
ALOGE("Failed to fstatat(%s): %s", buf, strerror(errno));
res = -errno;
goto done_close;
}
} else {
if (S_ISLNK(sb.st_mode)) {
ALOGE("Symbolic links are not allowed: %s", buf);
res = -ELOOP;
goto done_close;
}
if (!S_ISDIR(sb.st_mode)) {
ALOGE("Existing segment not a directory: %s", buf);
res = -ENOTDIR;
goto done_close;
}
}
/* Yay, segment is ready for us to step into */
int next_fd;
if ((next_fd = openat(fd, segment, 0)) == -1) {
ALOGE("Failed to openat(%s): %s", buf, strerror(errno));
res = -errno;
goto done_close;
}
close(fd);
fd = next_fd;
*p = '/';
segment = p + 1;
}
p++;
}
done_close:
close(fd);
done:
free(buf);
return res;
}
|
