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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 #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 
     34 void 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 
     54 int 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