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 #include <stdlib.h> 30 31 #define ALL_PERMS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO) 32 #define BUF_SIZE 64 33 34 int fs_prepare_dir(const char* path, mode_t mode, uid_t uid, gid_t gid) { 35 // Check if path needs to be created 36 struct stat sb; 37 if (TEMP_FAILURE_RETRY(lstat(path, &sb)) == -1) { 38 if (errno == ENOENT) { 39 goto create; 40 } else { 41 ALOGE("Failed to lstat(%s): %s", path, strerror(errno)); 42 return -1; 43 } 44 } 45 46 // Exists, verify status 47 if (!S_ISDIR(sb.st_mode)) { 48 ALOGE("Not a directory: %s", path); 49 return -1; 50 } 51 if (((sb.st_mode & ALL_PERMS) == mode) && (sb.st_uid == uid) && (sb.st_gid == gid)) { 52 return 0; 53 } else { 54 goto fixup; 55 } 56 57 create: 58 if (TEMP_FAILURE_RETRY(mkdir(path, mode)) == -1) { 59 if (errno != EEXIST) { 60 ALOGE("Failed to mkdir(%s): %s", path, strerror(errno)); 61 return -1; 62 } 63 } 64 65 fixup: 66 if (TEMP_FAILURE_RETRY(chmod(path, mode)) == -1) { 67 ALOGE("Failed to chmod(%s, %d): %s", path, mode, strerror(errno)); 68 return -1; 69 } 70 if (TEMP_FAILURE_RETRY(chown(path, uid, gid)) == -1) { 71 ALOGE("Failed to chown(%s, %d, %d): %s", path, uid, gid, strerror(errno)); 72 return -1; 73 } 74 75 return 0; 76 } 77 78 int fs_read_atomic_int(const char* path, int* out_value) { 79 int fd = TEMP_FAILURE_RETRY(open(path, O_RDONLY)); 80 if (fd == -1) { 81 ALOGE("Failed to read %s: %s", path, strerror(errno)); 82 return -1; 83 } 84 85 char buf[BUF_SIZE]; 86 if (TEMP_FAILURE_RETRY(read(fd, buf, BUF_SIZE)) == -1) { 87 ALOGE("Failed to read %s: %s", path, strerror(errno)); 88 goto fail; 89 } 90 if (sscanf(buf, "%d", out_value) != 1) { 91 ALOGE("Failed to parse %s: %s", path, strerror(errno)); 92 goto fail; 93 } 94 close(fd); 95 return 0; 96 97 fail: 98 close(fd); 99 *out_value = -1; 100 return -1; 101 } 102 103 int fs_write_atomic_int(const char* path, int value) { 104 char temp[PATH_MAX]; 105 if (snprintf(temp, PATH_MAX, "%s.XXXXXX", path) >= PATH_MAX) { 106 ALOGE("Path too long"); 107 return -1; 108 } 109 110 int fd = TEMP_FAILURE_RETRY(mkstemp(temp)); 111 if (fd == -1) { 112 ALOGE("Failed to open %s: %s", temp, strerror(errno)); 113 return -1; 114 } 115 116 char buf[BUF_SIZE]; 117 int len = snprintf(buf, BUF_SIZE, "%d", value) + 1; 118 if (len > BUF_SIZE) { 119 ALOGE("Value %d too large: %s", value, strerror(errno)); 120 goto fail; 121 } 122 if (TEMP_FAILURE_RETRY(write(fd, buf, len)) < len) { 123 ALOGE("Failed to write %s: %s", temp, strerror(errno)); 124 goto fail; 125 } 126 if (close(fd) == -1) { 127 ALOGE("Failed to close %s: %s", temp, strerror(errno)); 128 goto fail_closed; 129 } 130 131 if (rename(temp, path) == -1) { 132 ALOGE("Failed to rename %s to %s: %s", temp, path, strerror(errno)); 133 goto fail_closed; 134 } 135 136 return 0; 137 138 fail: 139 close(fd); 140 fail_closed: 141 unlink(temp); 142 return -1; 143 } 144
