69eead77ff
The CD now boots directly from the ISO 9660 filesystem instead of using MBR partitioning with Minix file systems. This saves some space on the CD and reduces memory requirements by some unknown amount as the root ramdisk is completely eliminated. The x86 hard drive image creation is also rewritten in the same fashion. The setup is modified to be more NetBSD-like (unpacking sets tarballs instead of blindly copying the CD contents). Splitting MINIX into sets is done in another commit due to it being a nightmare to rebase. Since MINIX lacks union mounts for now, a bunch of ramdisks are generated at run-time to make parts of the filesystem writeable for the CD. This solution isn't ideal, but it's enough for an installation CD. Change-Id: Icbd9cca4dafebf7b42c345b107a17679a622d5cd
88 lines
2 KiB
C
88 lines
2 KiB
C
/* This procedure examines a file system and figures out whether it is
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* version 1 or version 2. It returns the result as an int. If the
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* file system is neither, it returns -1. A typical call is:
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*
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* n = fsversion("/dev/hd1", "df");
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*
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* The first argument is the special file for the file system.
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* The second is the program name, which is used in error messages.
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*/
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#include <sys/types.h>
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#include <minix/config.h>
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#include <minix/const.h>
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#include <minix/minlib.h>
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#include <minix/type.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <string.h>
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#include "mfs/const.h"
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static char super[SUPER_BLOCK_BYTES];
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#define MAGIC_OFFSET_MFS 0x18
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#define MAGIC_OFFSET_EXT 0x38
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#define MAGIC_OFFSET_ISO9660 0x8000
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#define MAGIC_VALUE_EXT2 0xef53
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static int check_super(off_t offset, unsigned short magic)
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{
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return (memcmp(super + offset, &magic, sizeof(magic)) == 0) ? 1 : 0;
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}
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int fsversion(char *dev, char *prog)
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{
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int result = -1, fd;
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if ((fd = open(dev, O_RDONLY)) < 0) {
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std_err(prog);
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std_err(" cannot open ");
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perror(dev);
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return(-1);
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}
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lseek(fd, (off_t) SUPER_BLOCK_BYTES, SEEK_SET); /* skip boot block */
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if (read(fd, (char *) &super, sizeof(super)) != sizeof(super)) {
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std_err(prog);
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std_err(" cannot read super block on ");
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perror(dev);
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close(fd);
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return(-1);
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}
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/* first check MFS, a valid MFS may look like EXT but not vice versa */
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if (check_super(MAGIC_OFFSET_MFS, SUPER_MAGIC)) {
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result = FSVERSION_MFS1;
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goto done;
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}
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else if (check_super(MAGIC_OFFSET_MFS, SUPER_V2)) {
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result = FSVERSION_MFS2;
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goto done;
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}
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else if (check_super(MAGIC_OFFSET_MFS, SUPER_V3)) {
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result = FSVERSION_MFS3;
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goto done;
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}
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/* check ext2 */
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if (check_super(MAGIC_OFFSET_EXT, MAGIC_VALUE_EXT2)) {
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result = FSVERSION_EXT2;
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goto done;
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}
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/* check ISO 9660 */
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lseek(fd, (off_t) MAGIC_OFFSET_ISO9660, SEEK_SET);
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if (read(fd, (char *) &super, sizeof(super)) == sizeof(super)) {
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if (memcmp(super+1, "CD001", 5) == 0) {
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result = FSVERSION_ISO9660;
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goto done;
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}
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}
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done:
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close(fd);
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return result;
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}
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