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Diffstat (limited to 'arch/i386/boot/tools/build.c')
-rw-r--r--arch/i386/boot/tools/build.c162
1 files changed, 72 insertions, 90 deletions
diff --git a/arch/i386/boot/tools/build.c b/arch/i386/boot/tools/build.c
index 05798419a6a9..b4248740ff0d 100644
--- a/arch/i386/boot/tools/build.c
+++ b/arch/i386/boot/tools/build.c
@@ -1,13 +1,12 @@
/*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 1997 Martin Mares
+ * Copyright (C) 2007 H. Peter Anvin
*/
/*
- * This file builds a disk-image from three different files:
+ * This file builds a disk-image from two different files:
*
- * - bootsect: compatibility mbr which prints an error message if
- * someone tries to boot the kernel directly.
* - setup: 8086 machine code, sets up system parm
* - system: 80386 code for actual system
*
@@ -21,6 +20,7 @@
* High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
* Cross compiling fixes by Gertjan van Wingerde, July 1996
* Rewritten by Martin Mares, April 1997
+ * Substantially overhauled by H. Peter Anvin, April 2007
*/
#include <stdio.h>
@@ -32,23 +32,25 @@
#include <sys/sysmacros.h>
#include <unistd.h>
#include <fcntl.h>
+#include <sys/mman.h>
#include <asm/boot.h>
-typedef unsigned char byte;
-typedef unsigned short word;
-typedef unsigned long u32;
+typedef unsigned char u8;
+typedef unsigned short u16;
+typedef unsigned long u32;
#define DEFAULT_MAJOR_ROOT 0
#define DEFAULT_MINOR_ROOT 0
-/* Minimal number of setup sectors (see also bootsect.S) */
-#define SETUP_SECTS 4
+/* Minimal number of setup sectors */
+#define SETUP_SECT_MIN 5
+#define SETUP_SECT_MAX 64
-byte buf[1024];
-int fd;
+/* This must be large enough to hold the entire setup */
+u8 buf[SETUP_SECT_MAX*512];
int is_big_kernel;
-void die(const char * str, ...)
+static void die(const char * str, ...)
{
va_list args;
va_start(args, str);
@@ -57,15 +59,9 @@ void die(const char * str, ...)
exit(1);
}
-void file_open(const char *name)
+static void usage(void)
{
- if ((fd = open(name, O_RDONLY, 0)) < 0)
- die("Unable to open `%s': %m", name);
-}
-
-void usage(void)
-{
- die("Usage: build [-b] bootsect setup system [rootdev] [> image]");
+ die("Usage: build [-b] setup system [rootdev] [> image]");
}
int main(int argc, char ** argv)
@@ -73,27 +69,30 @@ int main(int argc, char ** argv)
unsigned int i, sz, setup_sectors;
int c;
u32 sys_size;
- byte major_root, minor_root;
+ u8 major_root, minor_root;
struct stat sb;
+ FILE *file;
+ int fd;
+ void *kernel;
if (argc > 2 && !strcmp(argv[1], "-b"))
{
is_big_kernel = 1;
argc--, argv++;
}
- if ((argc < 4) || (argc > 5))
+ if ((argc < 3) || (argc > 4))
usage();
- if (argc > 4) {
- if (!strcmp(argv[4], "CURRENT")) {
+ if (argc > 3) {
+ if (!strcmp(argv[3], "CURRENT")) {
if (stat("/", &sb)) {
perror("/");
die("Couldn't stat /");
}
major_root = major(sb.st_dev);
minor_root = minor(sb.st_dev);
- } else if (strcmp(argv[4], "FLOPPY")) {
- if (stat(argv[4], &sb)) {
- perror(argv[4]);
+ } else if (strcmp(argv[3], "FLOPPY")) {
+ if (stat(argv[3], &sb)) {
+ perror(argv[3]);
die("Couldn't stat root device.");
}
major_root = major(sb.st_rdev);
@@ -108,79 +107,62 @@ int main(int argc, char ** argv)
}
fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root);
- file_open(argv[1]);
- i = read(fd, buf, sizeof(buf));
- fprintf(stderr,"Boot sector %d bytes.\n",i);
- if (i != 512)
- die("Boot block must be exactly 512 bytes");
+ /* Copy the setup code */
+ file = fopen(argv[1], "r");
+ if (!file)
+ die("Unable to open `%s': %m", argv[1]);
+ c = fread(buf, 1, sizeof(buf), file);
+ if (ferror(file))
+ die("read-error on `setup'");
+ if (c < 1024)
+ die("The setup must be at least 1024 bytes");
if (buf[510] != 0x55 || buf[511] != 0xaa)
die("Boot block hasn't got boot flag (0xAA55)");
+ fclose(file);
+
+ /* Pad unused space with zeros */
+ setup_sectors = (c + 511) / 512;
+ if (setup_sectors < SETUP_SECT_MIN)
+ setup_sectors = SETUP_SECT_MIN;
+ i = setup_sectors*512;
+ memset(buf+c, 0, i-c);
+
+ /* Set the default root device */
buf[508] = minor_root;
buf[509] = major_root;
- if (write(1, buf, 512) != 512)
- die("Write call failed");
- close (fd);
-
- file_open(argv[2]); /* Copy the setup code */
- for (i=0 ; (c=read(fd, buf, sizeof(buf)))>0 ; i+=c )
- if (write(1, buf, c) != c)
- die("Write call failed");
- if (c != 0)
- die("read-error on `setup'");
- close (fd);
-
- setup_sectors = (i + 511) / 512; /* Pad unused space with zeros */
- /* for compatibility with ancient versions of LILO. */
- if (setup_sectors < SETUP_SECTS)
- setup_sectors = SETUP_SECTS;
- fprintf(stderr, "Setup is %d bytes.\n", i);
- memset(buf, 0, sizeof(buf));
- while (i < setup_sectors * 512) {
- c = setup_sectors * 512 - i;
- if (c > sizeof(buf))
- c = sizeof(buf);
- if (write(1, buf, c) != c)
- die("Write call failed");
- i += c;
- }
- file_open(argv[3]);
- if (fstat (fd, &sb))
- die("Unable to stat `%s': %m", argv[3]);
+ fprintf(stderr, "Setup is %d bytes (padded to %d bytes).\n", c, i);
+
+ /* Open and stat the kernel file */
+ fd = open(argv[2], O_RDONLY);
+ if (fd < 0)
+ die("Unable to open `%s': %m", argv[2]);
+ if (fstat(fd, &sb))
+ die("Unable to stat `%s': %m", argv[2]);
sz = sb.st_size;
- fprintf (stderr, "System is %d kB\n", sz/1024);
+ fprintf (stderr, "System is %d kB\n", (sz+1023)/1024);
+ kernel = mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0);
+ if (kernel == MAP_FAILED)
+ die("Unable to mmap '%s': %m", argv[2]);
sys_size = (sz + 15) / 16;
if (!is_big_kernel && sys_size > DEF_SYSSIZE)
die("System is too big. Try using bzImage or modules.");
- while (sz > 0) {
- int l, n;
-
- l = (sz > sizeof(buf)) ? sizeof(buf) : sz;
- if ((n=read(fd, buf, l)) != l) {
- if (n < 0)
- die("Error reading %s: %m", argv[3]);
- else
- die("%s: Unexpected EOF", argv[3]);
- }
- if (write(1, buf, l) != l)
- die("Write failed");
- sz -= l;
- }
+
+ /* Patch the setup code with the appropriate size parameters */
+ buf[0x1f1] = setup_sectors-1;
+ buf[0x1f4] = sys_size;
+ buf[0x1f5] = sys_size >> 8;
+ buf[0x1f6] = sys_size >> 16;
+ buf[0x1f7] = sys_size >> 24;
+
+ if (fwrite(buf, 1, i, stdout) != i)
+ die("Writing setup failed");
+
+ /* Copy the kernel code */
+ if (fwrite(kernel, 1, sz, stdout) != sz)
+ die("Writing kernel failed");
close(fd);
- if (lseek(1, 497, SEEK_SET) != 497) /* Write sizes to the bootsector */
- die("Output: seek failed");
- buf[0] = setup_sectors;
- if (write(1, buf, 1) != 1)
- die("Write of setup sector count failed");
- if (lseek(1, 500, SEEK_SET) != 500)
- die("Output: seek failed");
- buf[0] = (sys_size & 0xff);
- buf[1] = ((sys_size >> 8) & 0xff);
- buf[2] = ((sys_size >> 16) & 0xff);
- buf[3] = ((sys_size >> 24) & 0xff);
- if (write(1, buf, 4) != 4)
- die("Write of image length failed");
-
- return 0; /* Everything is OK */
+ /* Everything is OK */
+ return 0;
}
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