flash_image.c revision 39cf417e17011a72dd39acfe4cc8c90af26bdbaf 
1/*
2 * Copyright (C) 2008 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 <errno.h>
18#include <fcntl.h>
19#include <stdio.h>
20#include <stdlib.h>
21#include <string.h>
22#include <unistd.h>
23
24#include "cutils/log.h"
25#include "mtdutils.h"
26
27#ifdef LOG_TAG
28#undef LOG_TAG
29#endif
30#define LOG_TAG "flash_image"
31
32#define HEADER_SIZE 2048  // size of header to compare for equality
33
34void die(const char *msg, ...) {
35    int err = errno;
36    va_list args;
37    va_start(args, msg);
38    char buf[1024];
39    vsnprintf(buf, sizeof(buf), msg, args);
40    va_end(args);
41
42    if (err != 0) {
43        strlcat(buf, ": ", sizeof(buf));
44        strlcat(buf, strerror(err), sizeof(buf));
45    }
46
47    fprintf(stderr, "%s\n", buf);
48    ALOGE("%s\n", buf);
49    exit(1);
50}
51
52/* Read an image file and write it to a flash partition. */
53
54int main(int argc, char **argv) {
55    const MtdPartition *ptn;
56    MtdWriteContext *write;
57    void *data;
58    unsigned sz;
59
60    if (argc != 3) {
61        fprintf(stderr, "usage: %s partition file.img\n", argv[0]);
62        return 2;
63    }
64
65    if (mtd_scan_partitions() <= 0) die("error scanning partitions");
66    const MtdPartition *partition = mtd_find_partition_by_name(argv[1]);
67    if (partition == NULL) die("can't find %s partition", argv[1]);
68
69    // If the first part of the file matches the partition, skip writing
70
71    int fd = open(argv[2], O_RDONLY);
72    if (fd < 0) die("error opening %s", argv[2]);
73
74    char header[HEADER_SIZE];
75    int headerlen = read(fd, header, sizeof(header));
76    if (headerlen <= 0) die("error reading %s header", argv[2]);
77
78    MtdReadContext *in = mtd_read_partition(partition);
79    if (in == NULL) {
80        ALOGW("error opening %s: %s\n", argv[1], strerror(errno));
81        // just assume it needs re-writing
82    } else {
83        char check[HEADER_SIZE];
84        int checklen = mtd_read_data(in, check, sizeof(check));
85        if (checklen <= 0) {
86            ALOGW("error reading %s: %s\n", argv[1], strerror(errno));
87            // just assume it needs re-writing
88        } else if (checklen == headerlen && !memcmp(header, check, headerlen)) {
89            ALOGI("header is the same, not flashing %s\n", argv[1]);
90            return 0;
91        }
92        mtd_read_close(in);
93    }
94
95    // Skip the header (we'll come back to it), write everything else
96    ALOGI("flashing %s from %s\n", argv[1], argv[2]);
97
98    MtdWriteContext *out = mtd_write_partition(partition);
99    if (out == NULL) die("error writing %s", argv[1]);
100
101    char buf[HEADER_SIZE];
102    memset(buf, 0, headerlen);
103    int wrote = mtd_write_data(out, buf, headerlen);
104    if (wrote != headerlen) die("error writing %s", argv[1]);
105
106    int len;
107    while ((len = read(fd, buf, sizeof(buf))) > 0) {
108        wrote = mtd_write_data(out, buf, len);
109        if (wrote != len) die("error writing %s", argv[1]);
110    }
111    if (len < 0) die("error reading %s", argv[2]);
112
113    if (mtd_write_close(out)) die("error closing %s", argv[1]);
114
115    // Now come back and write the header last
116
117    out = mtd_write_partition(partition);
118    if (out == NULL) die("error re-opening %s", argv[1]);
119
120    wrote = mtd_write_data(out, header, headerlen);
121    if (wrote != headerlen) die("error re-writing %s", argv[1]);
122
123    // Need to write a complete block, so write the rest of the first block
124    size_t block_size;
125    if (mtd_partition_info(partition, NULL, &block_size, NULL))
126        die("error getting %s block size", argv[1]);
127
128    if (lseek(fd, headerlen, SEEK_SET) != headerlen)
129        die("error rewinding %s", argv[2]);
130
131    int left = block_size - headerlen;
132    while (left < 0) left += block_size;
133    while (left > 0) {
134        len = read(fd, buf, left > (int)sizeof(buf) ? (int)sizeof(buf) : left);
135        if (len <= 0) die("error reading %s", argv[2]);
136        if (mtd_write_data(out, buf, len) != len)
137            die("error writing %s", argv[1]);
138        left -= len;
139    }
140
141    if (mtd_write_close(out)) die("error closing %s", argv[1]);
142    return 0;
143}
144