tools/padjffs2/src/padjffs2.c

   1 /*
   2  * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 as published
   6  * by the Free Software Foundation.
   7  *
   8  */
   9
  10 #include <errno.h>
  11 #include <fcntl.h>
  12 #include <libgen.h>
  13 #include <stdio.h>
  14 #include <stdint.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include <unistd.h>
  18 #include <sys/types.h>
  19 #include <sys/stat.h>
  20
  21 static char *progname;
  22 static unsigned int xtra_offset;
  23 static unsigned char eof_mark[4] = {0xde, 0xad, 0xc0, 0xde};
  24 static unsigned char jffs2_pad_be[] = "\x19\x85\x20\x04\x04\x00\x00\x00\xc4\x94\xdb\xf4";
  25 static unsigned char jffs2_pad_le[] = "\x85\x19\x04\x20\x00\x00\x00\x04\xa8\xfb\xa0\xb4";
  26 static unsigned char *pad = eof_mark;
  27 static int pad_len = sizeof(eof_mark);
  28
  29 #define ERR(fmt, ...) do { \
  30         fflush(0); \
  31         fprintf(stderr, "[%s] *** error: " fmt "\n", \
  32                         progname, ## __VA_ARGS__ ); \
  33 } while (0)
  34
  35 #define ERRS(fmt, ...) do { \
  36         int save = errno; \
  37         fflush(0); \
  38         fprintf(stderr, "[%s] *** error: " fmt ", %s\n", \
  39                         progname, ## __VA_ARGS__, strerror(save)); \
  40 } while (0)
  41
  42 #define BUF_SIZE        (64 * 1024)
  43 #define ALIGN(_x,_y)    (((_x) + ((_y) - 1)) & ~((_y) - 1))
  44
  45 static int pad_image(char *name, uint32_t pad_mask)
  46 {
  47         char *buf;
  48         int fd;
  49         ssize_t in_len;
  50         ssize_t out_len;
  51         int ret = -1;
  52
  53         buf = malloc(BUF_SIZE);
  54         if (!buf) {
  55                 ERR("No memory for buffer");
  56                 goto out;
  57         }
  58
  59         fd = open(name, O_RDWR);
  60         if (fd < 0) {
  61                 ERRS("Unable to open %s", name);
  62                 goto free_buf;
  63         }
  64
  65         in_len = lseek(fd, 0, SEEK_END);
  66         if (in_len < 0)
  67                 goto close;
  68
  69         memset(buf, '\xff', BUF_SIZE);
  70
  71         in_len += xtra_offset;
  72
  73         out_len = in_len;
  74         while (pad_mask) {
  75                 uint32_t mask;
  76                 ssize_t t;
  77                 int i;
  78
  79                 for (i = 10; i < 32; i++) {
  80                         mask = 1UL << i;
  81                         if (pad_mask & mask)
  82                                 break;
  83                 }
  84
  85                 in_len = ALIGN(in_len, mask);
  86
  87                 for (i = 10; i < 32; i++) {
  88                         mask = 1UL << i;
  89                         if ((in_len & (mask - 1)) == 0)
  90                                 pad_mask &= ~mask;
  91                 }
  92
  93                 printf("padding image to %08x\n", (unsigned int) in_len - xtra_offset);
  94
  95                 while (out_len < in_len) {
  96                         ssize_t len;
  97
  98                         len = in_len - out_len;
  99                         if (len > BUF_SIZE)
 100                                 len = BUF_SIZE;
 101
 102                         t = write(fd, buf, len);
 103                         if (t != len) {
 104                                 ERRS("Unable to write to %s", name);
 105                                 goto close;
 106                         }
 107
 108                         out_len += len;
 109                 }
 110
 111                 /* write out the JFFS end-of-filesystem marker */
 112                 t = write(fd, pad, pad_len);
 113                 if (t != pad_len) {
 114                         ERRS("Unable to write to %s", name);
 115                         goto close;
 116                 }
 117                 out_len += pad_len;
 118         }
 119
 120         ret = 0;
 121
 122 close:
 123         close(fd);
 124 free_buf:
 125         free(buf);
 126 out:
 127         return ret;
 128 }
 129
 130 static int usage(void)
 131 {
 132         fprintf(stderr,
 133                 "Usage: %s file [<options>] [pad0] [pad1] [padN]\n"
 134                 "Options:\n"
 135                 "  -x <offset>:          Add an extra offset for padding data\n"
 136                 "  -J:                   Use a fake big-endian jffs2 padding element instead of EOF\n"
 137                 "                        This is used to work around broken boot loaders that\n"
 138                 "                        try to parse the entire firmware area as one big jffs2\n"
 139                 "  -j:                   (like -J, but little-endian instead of big-endian)\n"
 140                 "\n",
 141                 progname);
 142         return EXIT_FAILURE;
 143 }
 144
 145 int main(int argc, char* argv[])
 146 {
 147         char *image;
 148         uint32_t pad_mask;
 149         int ret = EXIT_FAILURE;
 150         int err;
 151         int ch, i;
 152
 153         progname = basename(argv[0]);
 154
 155         if (argc < 2)
 156                 return usage();
 157
 158         image = argv[1];
 159         argv++;
 160         argc--;
 161
 162         pad_mask = 0;
 163         while ((ch = getopt(argc, argv, "x:Jj")) != -1) {
 164                 switch (ch) {
 165                 case 'x':
 166                         xtra_offset = strtoul(optarg, NULL, 0);
 167                         fprintf(stderr, "assuming %u bytes offset\n",
 168                                 xtra_offset);
 169                         break;
 170                 case 'J':
 171                         pad = jffs2_pad_be;
 172                         pad_len = sizeof(jffs2_pad_be) - 1;
 173                         break;
 174                 case 'j':
 175                         pad = jffs2_pad_le;
 176                         pad_len = sizeof(jffs2_pad_le) - 1;
 177                         break;
 178                 default:
 179                         return usage();
 180                 }
 181         }
 182
 183         for (i = optind; i < argc; i++)
 184                 pad_mask |= strtoul(argv[i], NULL, 0) * 1024;
 185
 186         if (pad_mask == 0)
 187                 pad_mask = (4 * 1024) | (8 * 1024) | (64 * 1024) |
 188                            (128 * 1024);
 189
 190         err = pad_image(image, pad_mask);
 191         if (err)
 192                 goto out;
 193
 194         ret = EXIT_SUCCESS;
 195
 196 out:
 197         return ret;
 198 }