1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #define LOG_TAG "cutils" 18 19 #include <cutils/fs.h> 20 #include <cutils/log.h> 21 22 #include <sys/types.h> 23 #include <sys/stat.h> 24 #include <fcntl.h> 25 #include <unistd.h> 26 #include <errno.h> 27 #include <string.h> 28 #include <limits.h> 29 30 #define ALL_PERMS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO) 31 #define BUF_SIZE 64 32 33 int fs_prepare_dir(const char* path, mode_t mode, uid_t uid, gid_t gid) { 34 // Check if path needs to be created 35 struct stat sb; 36 if (TEMP_FAILURE_RETRY(lstat(path, &sb)) == -1) { 37 if (errno == ENOENT) { 38 goto create; 39 } else { 40 ALOGE("Failed to lstat(%s): %s", path, strerror(errno)); 41 return -1; 42 } 43 } 44 45 // Exists, verify status 46 if (!S_ISDIR(sb.st_mode)) { 47 ALOGE("Not a directory: %s", path); 48 return -1; 49 } 50 if (((sb.st_mode & ALL_PERMS) == mode) && (sb.st_uid == uid) && (sb.st_gid == gid)) { 51 return 0; 52 } else { 53 goto fixup; 54 } 55 56 create: 57 if (TEMP_FAILURE_RETRY(mkdir(path, mode)) == -1) { 58 if (errno != EEXIST) { 59 ALOGE("Failed to mkdir(%s): %s", path, strerror(errno)); 60 return -1; 61 } 62 } 63 64 fixup: 65 if (TEMP_FAILURE_RETRY(chmod(path, mode)) == -1) { 66 ALOGE("Failed to chmod(%s, %d): %s", path, mode, strerror(errno)); 67 return -1; 68 } 69 if (TEMP_FAILURE_RETRY(chown(path, uid, gid)) == -1) { 70 ALOGE("Failed to chown(%s, %d, %d): %s", path, uid, gid, strerror(errno)); 71 return -1; 72 } 73 74 return 0; 75 } 76 77 int fs_read_atomic_int(const char* path, int* out_value) { 78 int fd = TEMP_FAILURE_RETRY(open(path, O_RDONLY)); 79 if (fd == -1) { 80 ALOGE("Failed to read %s: %s", path, strerror(errno)); 81 return -1; 82 } 83 84 char buf[BUF_SIZE]; 85 if (TEMP_FAILURE_RETRY(read(fd, buf, BUF_SIZE)) == -1) { 86 ALOGE("Failed to read %s: %s", path, strerror(errno)); 87 goto fail; 88 } 89 if (sscanf(buf, "%d", out_value) != 1) { 90 ALOGE("Failed to parse %s: %s", path, strerror(errno)); 91 goto fail; 92 } 93 close(fd); 94 return 0; 95 96 fail: 97 close(fd); 98 *out_value = -1; 99 return -1; 100 } 101 102 int fs_write_atomic_int(const char* path, int value) { 103 char temp[PATH_MAX]; 104 if (snprintf(temp, PATH_MAX, "%s.XXXXXX", path) >= PATH_MAX) { 105 ALOGE("Path too long"); 106 return -1; 107 } 108 109 int fd = TEMP_FAILURE_RETRY(mkstemp(temp)); 110 if (fd == -1) { 111 ALOGE("Failed to open %s: %s", temp, strerror(errno)); 112 return -1; 113 } 114 115 char buf[BUF_SIZE]; 116 int len = snprintf(buf, BUF_SIZE, "%d", value) + 1; 117 if (len > BUF_SIZE) { 118 ALOGE("Value %d too large: %s", value, strerror(errno)); 119 goto fail; 120 } 121 if (TEMP_FAILURE_RETRY(write(fd, buf, len)) < len) { 122 ALOGE("Failed to write %s: %s", temp, strerror(errno)); 123 goto fail; 124 } 125 if (close(fd) == -1) { 126 ALOGE("Failed to close %s: %s", temp, strerror(errno)); 127 goto fail_closed; 128 } 129 130 if (rename(temp, path) == -1) { 131 ALOGE("Failed to rename %s to %s: %s", temp, path, strerror(errno)); 132 goto fail_closed; 133 } 134 135 return 0; 136 137 fail: 138 close(fd); 139 fail_closed: 140 unlink(temp); 141 return -1; 142 } 143
