arch/mn10300/boot/tools/build.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Copyright (C) 1991, 1992  Linus Torvalds
   4  *  Copyright (C) 1997 Martin Mares
   5  */
   6
   7 /*
   8  * This file builds a disk-image from three different files:
   9  *
  10  * - bootsect: exactly 512 bytes of 8086 machine code, loads the rest
  11  * - setup: 8086 machine code, sets up system parm
  12  * - system: 80386 code for actual system
  13  *
  14  * It does some checking that all files are of the correct type, and
  15  * just writes the result to stdout, removing headers and padding to
  16  * the right amount. It also writes some system data to stderr.
  17  */
  18
  19 /*
  20  * Changes by tytso to allow root device specification
  21  * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
  22  * Cross compiling fixes by Gertjan van Wingerde, July 1996
  23  * Rewritten by Martin Mares, April 1997
  24  */
  25
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <stdlib.h>
  29 #include <stdarg.h>
  30 #include <sys/types.h>
  31 #include <sys/stat.h>
  32 #include <sys/sysmacros.h>
  33 #include <unistd.h>
  34 #include <fcntl.h>
  35 #include <asm/boot.h>
  36
  37 #define DEFAULT_MAJOR_ROOT 0
  38 #define DEFAULT_MINOR_ROOT 0
  39
  40 /* Minimal number of setup sectors (see also bootsect.S) */
  41 #define SETUP_SECTS 4
  42
  43 uint8_t buf[1024];
  44 int fd;
  45 int is_big_kernel;
  46
  47 __attribute__((noreturn))
  48 void die(const char *str, ...)
  49 {
  50         va_list args;
  51         va_start(args, str);
  52         vfprintf(stderr, str, args);
  53         fputc('\n', stderr);
  54         exit(1);
  55 }
  56
  57 void file_open(const char *name)
  58 {
  59         fd = open(name, O_RDONLY, 0);
  60         if (fd < 0)
  61                 die("Unable to open `%s': %m", name);
  62 }
  63
  64 __attribute__((noreturn))
  65 void usage(void)
  66 {
  67         die("Usage: build [-b] bootsect setup system [rootdev] [> image]");
  68 }
  69
  70 int main(int argc, char **argv)
  71 {
  72         unsigned int i, c, sz, setup_sectors;
  73         uint32_t sys_size;
  74         uint8_t major_root, minor_root;
  75         struct stat sb;
  76
  77         if (argc > 2 && !strcmp(argv[1], "-b")) {
  78                 is_big_kernel = 1;
  79                 argc--, argv++;
  80         }
  81         if ((argc < 4) || (argc > 5))
  82                 usage();
  83         if (argc > 4) {
  84                 if (!strcmp(argv[4], "CURRENT")) {
  85                         if (stat("/", &sb)) {
  86                                 perror("/");
  87                                 die("Couldn't stat /");
  88                         }
  89                         major_root = major(sb.st_dev);
  90                         minor_root = minor(sb.st_dev);
  91                 } else if (strcmp(argv[4], "FLOPPY")) {
  92                         if (stat(argv[4], &sb)) {
  93                                 perror(argv[4]);
  94                                 die("Couldn't stat root device.");
  95                         }
  96                         major_root = major(sb.st_rdev);
  97                         minor_root = minor(sb.st_rdev);
  98                 } else {
  99                         major_root = 0;
 100                         minor_root = 0;
 101                 }
 102         } else {
 103                 major_root = DEFAULT_MAJOR_ROOT;
 104                 minor_root = DEFAULT_MINOR_ROOT;
 105         }
 106         fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root);
 107
 108         file_open(argv[1]);
 109         i = read(fd, buf, sizeof(buf));
 110         fprintf(stderr, "Boot sector %d bytes.\n", i);
 111         if (i != 512)
 112                 die("Boot block must be exactly 512 bytes");
 113         if (buf[510] != 0x55 || buf[511] != 0xaa)
 114                 die("Boot block hasn't got boot flag (0xAA55)");
 115         buf[508] = minor_root;
 116         buf[509] = major_root;
 117         if (write(1, buf, 512) != 512)
 118                 die("Write call failed");
 119         close(fd);
 120
 121         /* Copy the setup code */
 122         file_open(argv[2]);
 123         for (i = 0; (c = read(fd, buf, sizeof(buf))) > 0; i += c)
 124                 if (write(1, buf, c) != c)
 125                         die("Write call failed");
 126         if (c != 0)
 127                 die("read-error on `setup'");
 128         close(fd);
 129
 130         /* Pad unused space with zeros */
 131         setup_sectors = (i + 511) / 512;
 132         /* for compatibility with ancient versions of LILO. */
 133         if (setup_sectors < SETUP_SECTS)
 134                 setup_sectors = SETUP_SECTS;
 135         fprintf(stderr, "Setup is %d bytes.\n", i);
 136         memset(buf, 0, sizeof(buf));
 137         while (i < setup_sectors * 512) {
 138                 c = setup_sectors * 512 - i;
 139                 if (c > sizeof(buf))
 140                         c = sizeof(buf);
 141                 if (write(1, buf, c) != c)
 142                         die("Write call failed");
 143                 i += c;
 144         }
 145
 146         file_open(argv[3]);
 147         if (fstat(fd, &sb))
 148                 die("Unable to stat `%s': %m", argv[3]);
 149         sz = sb.st_size;
 150         fprintf(stderr, "System is %d kB\n", sz / 1024);
 151         sys_size = (sz + 15) / 16;
 152         /* 0x28000*16 = 2.5 MB, conservative estimate for the current maximum */
 153         if (sys_size > (is_big_kernel ? 0x28000 : DEF_SYSSIZE))
 154                 die("System is too big. Try using %smodules.",
 155                         is_big_kernel ? "" : "bzImage or ");
 156         if (sys_size > 0xffff)
 157                 fprintf(stderr,
 158                         "warning: kernel is too big for standalone boot "
 159                         "from floppy\n");
 160         while (sz > 0) {
 161                 int l, n;
 162
 163                 l = (sz > sizeof(buf)) ? sizeof(buf) : sz;
 164                 n = read(fd, buf, l);
 165                 if (n != l) {
 166                         if (n < 0)
 167                                 die("Error reading %s: %m", argv[3]);
 168                         else
 169                                 die("%s: Unexpected EOF", argv[3]);
 170                 }
 171                 if (write(1, buf, l) != l)
 172                         die("Write failed");
 173                 sz -= l;
 174         }
 175         close(fd);
 176
 177         /* Write sizes to the bootsector */
 178         if (lseek(1, 497, SEEK_SET) != 497)
 179                 die("Output: seek failed");
 180         buf[0] = setup_sectors;
 181         if (write(1, buf, 1) != 1)
 182                 die("Write of setup sector count failed");
 183         if (lseek(1, 500, SEEK_SET) != 500)
 184                 die("Output: seek failed");
 185         buf[0] = (sys_size & 0xff);
 186         buf[1] = ((sys_size >> 8) & 0xff);
 187         if (write(1, buf, 2) != 2)
 188                 die("Write of image length failed");
 189
 190         return 0;
 191 }