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 <cutils/partition_utils.h>
18
19 #include <fcntl.h>
20 #include <sys/ioctl.h>
21 #include <sys/mount.h> /* for BLKGETSIZE */
22 #include <sys/stat.h>
23 #include <sys/types.h>
24 #include <unistd.h>
25
26 #include <cutils/properties.h>
27
only_one_char(uint8_t * buf,int len,uint8_t c)28 static int only_one_char(uint8_t *buf, int len, uint8_t c)
29 {
30 int i, ret;
31
32 ret = 1;
33 for (i=0; i<len; i++) {
34 if (buf[i] != c) {
35 ret = 0;
36 break;
37 }
38 }
39 return ret;
40 }
41
partition_wiped(const char * source)42 int partition_wiped(const char* source) {
43 uint8_t buf[4096];
44 int fd, ret;
45
46 if ((fd = open(source, O_RDONLY)) < 0) {
47 return 0;
48 }
49
50 ret = read(fd, buf, sizeof(buf));
51 close(fd);
52
53 if (ret != sizeof(buf)) {
54 return 0;
55 }
56
57 /* Check for all zeros */
58 if (only_one_char(buf, sizeof(buf), 0)) {
59 return 1;
60 }
61
62 /* Check for all ones */
63 if (only_one_char(buf, sizeof(buf), 0xff)) {
64 return 1;
65 }
66
67 return 0;
68 }
69