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 <stdbool.h>
  19 #include <sys/types.h>
  20 #include <sys/stat.h>
  21
  22 static char *progname;
  23 static unsigned int xtra_offset;
  24 static unsigned char eof_mark[4] = {0xde, 0xad, 0xc0, 0xde};
  25 static unsigned char jffs2_pad_be[] = "\x19\x85\x20\x04\x04\x00\x00\x00\xc4\x94\xdb\xf4";
  26 static unsigned char jffs2_pad_le[] = "\x85\x19\x04\x20\x00\x00\x00\x04\xa8\xfb\xa0\xb4";
  27 static unsigned char *pad = eof_mark;
  28 static int pad_len = sizeof(eof_mark);
  29 static bool pad_to_stdout = false;
  30
  31 #define ERR(fmt, ...) do { \
  32         fflush(0); \
  33         fprintf(stderr, "[%s] *** error: " fmt "\n", \
  34                         progname, ## __VA_ARGS__ ); \
  35 } while (0)
  36
  37 #define ERRS(fmt, ...) do { \
  38         int save = errno; \
  39         fflush(0); \
  40         fprintf(stderr, "[%s] *** error: " fmt ", %s\n", \
  41                         progname, ## __VA_ARGS__, strerror(save)); \
  42 } while (0)
  43
  44 #define BUF_SIZE        (64 * 1024)
  45 #define ALIGN(_x,_y)    (((_x) + ((_y) - 1)) & ~((_y) - 1))
  46
  47 static int pad_image(char *name, uint32_t pad_mask)
  48 {
  49         char *buf;
  50         int fd;
  51         int outfd;
  52         ssize_t in_len;
  53         ssize_t out_len;
  54         int ret = -1;
  55
  56         buf = malloc(BUF_SIZE);
  57         if (!buf) {
  58                 ERR("No memory for buffer");
  59                 goto out;
  60         }
  61
  62         fd = open(name, O_RDWR);
  63         if (fd < 0) {
  64                 ERRS("Unable to open %s", name);
  65                 goto free_buf;
  66         }
  67
  68         in_len = lseek(fd, 0, SEEK_END);
  69         if (in_len < 0)
  70                 goto close;
  71
  72         if (!pad_to_stdout)
  73                 outfd = fd;
  74         else
  75                 outfd = STDOUT_FILENO;
  76
  77         memset(buf, '\xff', BUF_SIZE);
  78
  79         in_len += xtra_offset;
  80
  81         out_len = in_len;
  82         while (pad_mask) {
  83                 uint32_t mask;
  84                 ssize_t t;
  85                 int i;
  86
  87                 for (i = 10; i < 32; i++) {
  88                         mask = 1UL << i;
  89                         if (pad_mask & mask)
  90                                 break;
  91                 }
  92
  93                 in_len = ALIGN(in_len, mask);
  94
  95                 for (i = 10; i < 32; i++) {
  96                         mask = 1UL << i;
  97                         if ((in_len & (mask - 1)) == 0)
  98                                 pad_mask &= ~mask;
  99                 }
 100
 101                 fprintf(stderr, "padding image to %08x\n", (unsigned int) in_len - xtra_offset);
 102
 103                 while (out_len < in_len) {
 104                         ssize_t len;
 105
 106                         len = in_len - out_len;
 107                         if (len > BUF_SIZE)
 108                                 len = BUF_SIZE;
 109
 110                         t = write(outfd, buf, len);
 111                         if (t != len) {
 112                                 ERRS("Unable to write to %s", name);
 113                                 goto close;
 114                         }
 115
 116                         out_len += len;
 117                 }
 118
 119                 /* write out the JFFS end-of-filesystem marker */
 120                 t = write(outfd, pad, pad_len);
 121                 if (t != pad_len) {
 122                         ERRS("Unable to write to %s", name);
 123                         goto close;
 124                 }
 125                 out_len += pad_len;
 126         }
 127
 128         ret = 0;
 129
 130 close:
 131         close(fd);
 132 free_buf:
 133         free(buf);
 134 out:
 135         return ret;
 136 }
 137
 138 static int usage(void)
 139 {
 140         fprintf(stderr,
 141                 "Usage: %s file [<options>] [pad0] [pad1] [padN]\n"
 142                 "Options:\n"
 143                 "  -x <offset>:          Add an extra offset for padding data\n"
 144                 "  -J:                   Use a fake big-endian jffs2 padding element instead of EOF\n"
 145                 "                        This is used to work around broken boot loaders that\n"
 146                 "                        try to parse the entire firmware area as one big jffs2\n"
 147                 "  -j:                   (like -J, but little-endian instead of big-endian)\n"
 148                 "  -c:                   write padding to stdout\n"
 149                 "\n",
 150                 progname);
 151         return EXIT_FAILURE;
 152 }
 153
 154 int main(int argc, char* argv[])
 155 {
 156         char *image;
 157         uint32_t pad_mask;
 158         int ret = EXIT_FAILURE;
 159         int err;
 160         int ch, i;
 161
 162         progname = basename(argv[0]);
 163
 164         if (argc < 2)
 165                 return usage();
 166
 167         image = argv[1];
 168         argv++;
 169         argc--;
 170
 171         pad_mask = 0;
 172         while ((ch = getopt(argc, argv, "x:Jjc")) != -1) {
 173                 switch (ch) {
 174                 case 'x':
 175                         xtra_offset = strtoul(optarg, NULL, 0);
 176                         fprintf(stderr, "assuming %u bytes offset\n",
 177                                 xtra_offset);
 178                         break;
 179                 case 'J':
 180                         pad = jffs2_pad_be;
 181                         pad_len = sizeof(jffs2_pad_be) - 1;
 182                         break;
 183                 case 'j':
 184                         pad = jffs2_pad_le;
 185                         pad_len = sizeof(jffs2_pad_le) - 1;
 186                         break;
 187                 case 'c':
 188                         pad_to_stdout = true;
 189                         break;
 190                 default:
 191                         return usage();
 192                 }
 193         }
 194
 195         for (i = optind; i < argc; i++)
 196                 pad_mask |= strtoul(argv[i], NULL, 0) * 1024;
 197
 198         if (pad_mask == 0)
 199                 pad_mask = (4 * 1024) | (8 * 1024) | (64 * 1024) |
 200                            (128 * 1024);
 201
 202         err = pad_image(image, pad_mask);
 203         if (err)
 204                 goto out;
 205
 206         ret = EXIT_SUCCESS;
 207
 208 out:
 209         return ret;
 210 }