1 /* 2 * Copyright 2011, 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 #include <fcntl.h> 18 #include <sys/ioctl.h> 19 #include <sys/mount.h> /* for BLKGETSIZE */ 20 #include <sys/stat.h> 21 #include <sys/types.h> 22 #include <unistd.h> 23 24 #include <cutils/properties.h> 25 26 static int only_one_char(char *buf, int len, char c) 27 { 28 int i, ret; 29 30 ret = 1; 31 for (i=0; i<len; i++) { 32 if (buf[i] != c) { 33 ret = 0; 34 break; 35 } 36 } 37 return ret; 38 } 39 40 int partition_wiped(char *source) 41 { 42 char buf[4096]; 43 int fd, ret; 44 45 if ((fd = open(source, O_RDONLY)) < 0) { 46 return 0; 47 } 48 49 ret = read(fd, buf, sizeof(buf)); 50 close(fd); 51 52 if (ret != sizeof(buf)) { 53 return 0; 54 } 55 56 /* Check for all zeros */ 57 if (only_one_char(buf, sizeof(buf), 0)) { 58 return 1; 59 } 60 61 /* Check for all ones */ 62 if (only_one_char(buf, sizeof(buf), 0xff)) { 63 return 1; 64 } 65 66 return 0; 67 } 68 69
