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