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/*
* 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/* These defines are only needed because prebuilt headers are out of date */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;
}
#ifndef __APPLE__
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, O_NOFOLLOW | O_CLOEXEC)) == -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;
}
#endif
|
