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