boot/x86_64/makeflop.c

   1 /*
   2 ** Copyright 2001, Travis Geiselbrecht. All rights reserved.
   3 ** Distributed under the terms of the NewOS License.
   4 */
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <sys/stat.h>
   8 #include <unistd.h>
   9 #include <fcntl.h>
  10
  11 #ifndef O_BINARY
  12 #define O_BINARY 0
  13 #endif
  14
  15 void usage(char const *progname)
  16 {
  17         printf("usage: %s [-p #padding] bootblock payload outfile\n", progname);
  18 }
  19
  20 int main(int argc, char *argv[])
  21 {
  22         struct stat st;
  23         int err;
  24         unsigned int blocks;
  25         unsigned char bootsector[1024];
  26         unsigned char buf[512];
  27         size_t read_size;
  28         size_t written_bytes;
  29         int padding;
  30         int infd;
  31         int outfd;
  32         signed char opt;
  33         char const *progname;
  34
  35         padding = 0;
  36         progname = argv[0];
  37
  38         while( (opt = getopt(argc, argv, "p:")) != -1)
  39                 switch (opt) {
  40                 case 'p':
  41                         padding= atoi(optarg);
  42                         if (padding < 0) {
  43                                 usage(progname);
  44                                 return -1;
  45                         }
  46                         break;
  47                 case '?':
  48                 default:
  49                         usage(progname);
  50                         return -1;
  51         }
  52         argc -= optind - 1;
  53         argv += optind - 1;
  54
  55         if(argc < 4) {
  56                 printf("insufficient args\n");
  57                 usage(progname);
  58                 return -1;
  59         }
  60
  61         err = stat(argv[2], &st);
  62         if(err < 0) {
  63                 printf("error stating file '%s'\n", argv[2]);
  64                 return -1;
  65         }
  66
  67         outfd = open(argv[3], O_BINARY|O_WRONLY|O_CREAT|O_TRUNC, 0666);
  68         if(outfd < 0) {
  69                 printf("error: cannot open output file '%s'\n", argv[3]);
  70                 return -1;
  71         }
  72
  73         // first read the bootblock
  74         infd = open(argv[1], O_BINARY|O_RDONLY);
  75         if(infd < 0) {
  76                 printf("error: cannot open bootblock file '%s'\n", argv[1]);
  77                 return -1;
  78         }
  79         if(read(infd, bootsector, sizeof(bootsector)) < sizeof(bootsector)
  80           || lseek(infd, 0, SEEK_END) != sizeof(bootsector)) {
  81                 printf ("error: size of bootblock file '%s' must match %d bytes.\n", argv[1], sizeof(bootsector));
  82                 return -1;
  83         }
  84         close(infd);
  85
  86         // patch the size of the output into bytes 3 & 4 of the bootblock
  87         blocks = st.st_size / 512;
  88         if((st.st_size % 512) != 0)
  89                 blocks++;
  90         printf("size %d, blocks %d (size %d)\n", (unsigned long)st.st_size, blocks, blocks * 512);
  91         bootsector[2] = (blocks & 0x00ff);
  92         bootsector[3] = (blocks & 0xff00) >> 8;
  93
  94         write(outfd, bootsector, sizeof(bootsector));
  95         written_bytes = sizeof(bootsector);
  96
  97         infd = open(argv[2], O_BINARY|O_RDONLY);
  98         if(infd < 0) {
  99                 printf("error: cannot open input file '%s'\n", argv[1]);
 100                 return -1;
 101         }
 102
 103         while((read_size = read(infd, buf, sizeof(buf))) > 0) {
 104                 write(outfd, buf, read_size);
 105                 written_bytes += read_size;
 106         }
 107
 108         if (padding) {
 109                 if (written_bytes % padding) {
 110                         size_t towrite = padding - written_bytes % padding;
 111                         unsigned char *buf = malloc(towrite);
 112
 113                         memset(buf, 0, towrite);
 114                         write(outfd, buf, towrite);
 115                         written_bytes+= towrite;
 116
 117                         printf("output file padded to %ld\n", (unsigned long)written_bytes);
 118                 }
 119         }
 120
 121         close(outfd);
 122         close(infd);
 123
 124         return 0;
 125 }
 126