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(2006-08-06) rescue-bootcd

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This commit is contained in:
Valeriano A.R.
2006-08-06 00:00:00 +02:00
parent 2f796b816a
commit decb062d20
21091 changed files with 7076462 additions and 0 deletions
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756
extra/syslinux-3.09/extlinux/extlinux.c Normal file
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#ident "$Id: extlinux.c,v 1.15 2005/04/03 00:00:36 hpa Exp $"
/* ----------------------------------------------------------------------- *
*
* Copyright 1998-2005 H. Peter Anvin - All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, Inc., 53 Temple Place Ste 330,
* Boston MA 02111-1307, USA; either version 2 of the License, or
* (at your option) any later version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/*
* extlinux.c
*
* Install the extlinux boot block on an ext2/3 filesystem
*/
#define _GNU_SOURCE /* Enable everything */
#include <inttypes.h>
/* This is needed to deal with the kernel headers imported into glibc 3.3.3. */
typedef uint64_t u64;
#include <alloca.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <mntent.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <sysexits.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/mount.h>
#include <linux/fd.h> /* Floppy geometry */
#include <linux/hdreg.h> /* Hard disk geometry */
#include <linux/fs.h> /* FIGETBSZ, FIBMAP */
#include "ext2_fs.h"
#include "../version.h"
#ifdef DEBUG
# define dprintf printf
#else
# define dprintf(...) ((void)0)
#endif
/* Global option handling */
const char *program;
/* These are the options we can set and their values */
struct my_options {
unsigned int sectors;
unsigned int heads;
} opt = {
.sectors = 0,
.heads = 0,
};
static void __attribute__((noreturn)) usage(int rv)
{
fprintf(stderr,
"Usage: %s [options] directory\n"
" --zip -z Force zipdrive geometry (-H 64 -S 32)\n"
" --sectors=# -S Force the number of sectors per track\n"
" --heads=# -H Force number of heads\n"
"\n"
" Note: geometry is determined at boot time for devices which\n"
" are considered hard disks by the BIOS. Unfortunately, this is\n"
" not possible for devices which are considered floppy disks,\n"
" which includes zipdisks and LS-120 superfloppies.\n"
"\n"
" The -z option is useful for USB devices which are considered\n"
" hard disks by some BIOSes and zipdrives by other BIOSes.\n",
program);
exit(rv);
}
static const struct option long_options[] = {
{ "zipdrive", 0, NULL, 'z' },
{ "sectors", 1, NULL, 'S' },
{ "heads", 1, NULL, 'H' },
{ "version", 0, NULL, 'v' },
{ "help", 0, NULL, 'h' },
{ 0, 0, 0, 0 }
};
static const char short_options[] = "zS:H:vh";
#if defined(__linux__) && !defined(BLKGETSIZE64)
/* This takes a u64, but the size field says size_t. Someone screwed big. */
# define BLKGETSIZE64 _IOR(0x12,114,size_t)
#endif
#define LDLINUX_MAGIC 0x3eb202fe
enum bs_offsets {
bsJump = 0x00,
bsOemName = 0x03,
bsBytesPerSec = 0x0b,
bsSecPerClust = 0x0d,
bsResSectors = 0x0e,
bsFATs = 0x10,
bsRootDirEnts = 0x11,
bsSectors = 0x13,
bsMedia = 0x15,
bsFATsecs = 0x16,
bsSecPerTrack = 0x18,
bsHeads = 0x1a,
bsHiddenSecs = 0x1c,
bsHugeSectors = 0x20,
/* FAT12/16 only */
bs16DriveNumber = 0x24,
bs16Reserved1 = 0x25,
bs16BootSignature = 0x26,
bs16VolumeID = 0x27,
bs16VolumeLabel = 0x2b,
bs16FileSysType = 0x36,
bs16Code = 0x3e,
/* FAT32 only */
bs32FATSz32 = 36,
bs32ExtFlags = 40,
bs32FSVer = 42,
bs32RootClus = 44,
bs32FSInfo = 48,
bs32BkBootSec = 50,
bs32Reserved = 52,
bs32DriveNumber = 64,
bs32Reserved1 = 65,
bs32BootSignature = 66,
bs32VolumeID = 67,
bs32VolumeLabel = 71,
bs32FileSysType = 82,
bs32Code = 90,
bsSignature = 0x1fe
};
#define bsHead bsJump
#define bsHeadLen (bsOemName-bsHead)
#define bsCode bs32Code /* The common safe choice */
#define bsCodeLen (bsSignature-bs32Code)
/*
* Access functions for littleendian numbers, possibly misaligned.
*/
static inline uint8_t get_8(const unsigned char *p)
{
return *(const uint8_t *)p;
}
static inline uint16_t get_16(const unsigned char *p)
{
#if defined(__i386__) || defined(__x86_64__)
/* Littleendian and unaligned-capable */
return *(const uint16_t *)p;
#else
return (uint16_t)p[0] + ((uint16_t)p[1] << 8);
#endif
}
static inline uint32_t get_32(const unsigned char *p)
{
#if defined(__i386__) || defined(__x86_64__)
/* Littleendian and unaligned-capable */
return *(const uint32_t *)p;
#else
return (uint32_t)p[0] + ((uint32_t)p[1] << 8) +
((uint32_t)p[2] << 16) + ((uint32_t)p[3] << 24);
#endif
}
static inline void set_16(unsigned char *p, uint16_t v)
{
#if defined(__i386__) || defined(__x86_64__)
/* Littleendian and unaligned-capable */
*(uint16_t *)p = v;
#else
p[0] = (v & 0xff);
p[1] = ((v >> 8) & 0xff);
#endif
}
static inline void set_32(unsigned char *p, uint32_t v)
{
#if defined(__i386__) || defined(__x86_64__)
/* Littleendian and unaligned-capable */
*(uint32_t *)p = v;
#else
p[0] = (v & 0xff);
p[1] = ((v >> 8) & 0xff);
p[2] = ((v >> 16) & 0xff);
p[3] = ((v >> 24) & 0xff);
#endif
}
#ifndef EXT2_SUPER_OFFSET
#define EXT2_SUPER_OFFSET 1024
#endif
#define SECTOR_SHIFT 9 /* 512-byte sectors */
#define SECTOR_SIZE (1 << SECTOR_SHIFT)
const char *program;
/*
* Boot block
*/
extern unsigned char extlinux_bootsect[];
extern unsigned int extlinux_bootsect_len;
#define boot_block extlinux_bootsect
#define boot_block_len extlinux_bootsect_len
/*
* Image file
*/
extern unsigned char extlinux_image[];
extern unsigned int extlinux_image_len;
#define boot_image extlinux_image
#define boot_image_len extlinux_image_len
/*
* Common abort function
*/
void __attribute__((noreturn)) die(const char *msg)
{
fputs(msg, stderr);
exit(1);
}
/*
* read/write wrapper functions
*/
ssize_t xpread(int fd, void *buf, size_t count, off_t offset)
{
char *bufp = (char *)buf;
ssize_t rv;
ssize_t done = 0;
while ( count ) {
rv = pread(fd, bufp, count, offset);
if ( rv == 0 ) {
die("short read");
} else if ( rv == -1 ) {
if ( errno == EINTR ) {
continue;
} else {
die(strerror(errno));
}
} else {
bufp += rv;
offset += rv;
done += rv;
count -= rv;
}
}
return done;
}
ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset)
{
const char *bufp = (const char *)buf;
ssize_t rv;
ssize_t done = 0;
while ( count ) {
rv = pwrite(fd, bufp, count, offset);
if ( rv == 0 ) {
die("short write");
} else if ( rv == -1 ) {
if ( errno == EINTR ) {
continue;
} else {
die(strerror(errno));
}
} else {
bufp += rv;
offset += rv;
done += rv;
count -= rv;
}
}
return done;
}
/*
* Produce file map
*/
int
sectmap(int fd, uint32_t *sectors, int nsectors)
{
unsigned int blksize, blk, nblk;
unsigned int i;
/* Get block size */
if ( ioctl(fd, FIGETBSZ, &blksize) )
return -1;
/* Number of sectors per block */
blksize >>= SECTOR_SHIFT;
nblk = 0;
while ( nsectors ) {
blk = nblk++;
dprintf("querying block %u\n", blk);
if ( ioctl(fd, FIBMAP, &blk) )
return -1;
blk *= blksize;
for ( i = 0 ; i < blksize ; i++ ) {
if ( !nsectors )
return 0;
dprintf("Sector: %10u\n", blk);
*sectors++ = blk++;
nsectors--;
}
}
return 0;
}
/*
* Get the size of a block device
*/
uint64_t get_size(int devfd)
{
uint64_t bytes;
uint32_t sects;
struct stat st;
#ifdef BLKGETSIZE64
if ( !ioctl(devfd, BLKGETSIZE64, &bytes) )
return bytes;
#endif
if ( !ioctl(devfd, BLKGETSIZE, &sects) )
return (uint64_t)sects << 9;
else if ( !fstat(devfd, &st) && st.st_size )
return st.st_size;
else
return 0;
}
/*
* Get device geometry and partition offset
*/
struct geometry_table {
uint64_t bytes;
struct hd_geometry g;
};
/* Standard floppy disk geometries, plus LS-120. Zipdisk geometry
(x/64/32) is the final fallback. I don't know what LS-240 has
as its geometry, since I don't have one and don't know anyone that does,
and Google wasn't helpful... */
static const struct geometry_table standard_geometries[] = {
{ 360*1024, { 2, 9, 40, 0 } },
{ 720*1024, { 2, 9, 80, 0 } },
{ 1200*1024, { 2, 15, 80, 0 } },
{ 1440*1024, { 2, 18, 80, 0 } },
{ 1680*1024, { 2, 21, 80, 0 } },
{ 1722*1024, { 2, 21, 80, 0 } },
{ 2880*1024, { 2, 36, 80, 0 } },
{ 3840*1024, { 2, 48, 80, 0 } },
{ 123264*1024, { 8, 32, 963, 0 } }, /* LS120 */
{ 0, {0,0,0,0} }
};
int
get_geometry(int devfd, uint64_t totalbytes, struct hd_geometry *geo)
{
struct floppy_struct fd_str;
const struct geometry_table *gp;
memset(geo, 0, sizeof *geo);
if ( !ioctl(devfd, HDIO_GETGEO, &geo) ) {
return 0;
} else if ( !ioctl(devfd, FDGETPRM, &fd_str) ) {
geo->heads = fd_str.head;
geo->sectors = fd_str.sect;
geo->cylinders = fd_str.track;
geo->start = 0;
return 0;
}
/* Didn't work. Let's see if this is one of the standard geometries */
for ( gp = standard_geometries ; gp->bytes ; gp++ ) {
if ( gp->bytes == totalbytes ) {
memcpy(geo, &gp->g, sizeof *geo);
return 0;
}
}
/* Didn't work either... assign a geometry of 64 heads, 32 sectors; this is
what zipdisks use, so this would help if someone has a USB key that
they're booting in USB-ZIP mode. */
geo->heads = opt.heads ?: 64;
geo->sectors = opt.sectors ?: 32;
geo->cylinders = totalbytes/(geo->heads*geo->sectors << SECTOR_SHIFT);
geo->start = 0;
if ( !opt.sectors && !opt.heads )
fprintf(stderr, "Warning: unable to obtain device geometry (defaulting to %d heads, %d sectors)\n"
" (on hard disks, this is usually harmless.)\n",
geo->heads, geo->sectors);
return 1;
}
/*
* Query the device geometry and put it into the boot sector.
* Map the file and put the map in the boot sector and file.
* Stick the "current directory" inode number into the file.
*/
void
patch_file_and_bootblock(int fd, int dirfd, int devfd)
{
struct stat dirst;
struct hd_geometry geo;
uint32_t *sectp;
uint64_t totalbytes, totalsectors;
int nsect;
unsigned char *p, *patcharea;
int i, dw;
uint32_t csum;
if ( fstat(dirfd, &dirst) ) {
perror("fstat dirfd");
exit(255); /* This should never happen */
}
totalbytes = get_size(devfd);
get_geometry(devfd, totalbytes, &geo);
if ( opt.heads )
geo.heads = opt.heads;
if ( opt.sectors )
geo.sectors = opt.sectors;
/* Patch this into a fake FAT superblock. This isn't because
FAT is a good format in any way, it's because it lets the
early bootstrap share code with the FAT version. */
dprintf("heads = %u, sect = %u\n", geo.heads, geo.sectors);
totalsectors = totalbytes >> SECTOR_SHIFT;
if ( totalsectors >= 65536 ) {
set_16(boot_block+bsSectors, 0);
} else {
set_16(boot_block+bsSectors, totalsectors);
}
set_32(boot_block+bsHugeSectors, totalsectors);
set_16(boot_block+bsBytesPerSec, SECTOR_SIZE);
set_16(boot_block+bsSecPerTrack, geo.sectors);
set_16(boot_block+bsHeads, geo.heads);
set_32(boot_block+bsHiddenSecs, geo.start);
/* Construct the boot file */
dprintf("directory inode = %lu\n", (unsigned long) dirst.st_ino);
nsect = (boot_image_len+SECTOR_SIZE-1) >> SECTOR_SHIFT;
sectp = alloca(sizeof(uint32_t)*nsect);
if ( sectmap(fd, sectp, nsect) ) {
perror("bmap");
exit(1);
}
/* First sector need pointer in boot sector */
set_32(boot_block+0x1F8, *sectp++);
nsect--;
/* Search for LDLINUX_MAGIC to find the patch area */
for ( p = boot_image ; get_32(p) != LDLINUX_MAGIC ; p += 4 );
patcharea = p+8;
/* Set up the totals */
dw = boot_image_len >> 2; /* COMPLETE dwords! */
set_16(patcharea, dw);
set_16(patcharea+2, nsect); /* Does not include the first sector! */
set_32(patcharea+8, dirst.st_ino); /* "Current" directory */
/* Set the sector pointers */
p = patcharea+12;
memset(p, 0, 64*4);
while ( nsect-- ) {
set_32(p, *sectp++);
p += 4;
}
/* Now produce a checksum */
set_32(patcharea+4, 0);
csum = LDLINUX_MAGIC;
for ( i = 0, p = boot_image ; i < dw ; i++, p += 4 )
csum -= get_32(p); /* Negative checksum */
set_32(patcharea+4, csum);
}
/*
* Install the boot block on the specified device.
* Must be run AFTER install_file()!
*/
int
install_bootblock(int fd, const char *device)
{
struct ext2_super_block sb;
if ( xpread(fd, &sb, sizeof sb, EXT2_SUPER_OFFSET) != sizeof sb ) {
perror("reading superblock");
return 1;
}
if ( sb.s_magic != EXT2_SUPER_MAGIC ) {
fprintf(stderr, "no ext2/ext3 superblock found on %s\n", device);
return 1;
}
if ( xpwrite(fd, boot_block, boot_block_len, 0) != boot_block_len ) {
perror("writing bootblock");
return 1;
}
return 0;
}
int
install_file(const char *path, int devfd, struct stat *rst)
{
char *file;
int fd = -1, dirfd = -1, flags;
struct stat st;
asprintf(&file, "%s%sextlinux.sys",
path,
path[0] && path[strlen(path)-1] == '/' ? "" : "/");
if ( !file ) {
perror(program);
return 1;
}
dirfd = open(path, O_RDONLY|O_DIRECTORY);
if ( dirfd < 0 ) {
perror(path);
goto bail;
}
fd = open(file, O_RDONLY);
if ( fd < 0 ) {
if ( errno != ENOENT ) {
perror(file);
goto bail;
}
} else {
/* If file exist, remove the immutable flag and set u+w mode */
if ( !ioctl(fd, EXT2_IOC_GETFLAGS, &flags) ) {
flags &= ~EXT2_IMMUTABLE_FL;
ioctl(fd, EXT2_IOC_SETFLAGS, &flags);
}
if ( !fstat(fd, &st) ) {
fchmod(fd, st.st_mode | S_IWUSR);
}
}
close(fd);
fd = open(file, O_WRONLY|O_TRUNC|O_CREAT, S_IRUSR|S_IRGRP|S_IROTH);
if ( fd < 0 ) {
perror(file);
goto bail;
}
/* Write it the first time */
if ( xpwrite(fd, boot_image, boot_image_len, 0) != boot_image_len ) {
fprintf(stderr, "%s: write failure on %s\n", program, file);
goto bail;
}
/* Map the file, and patch the initial sector accordingly */
patch_file_and_bootblock(fd, dirfd, devfd);
/* Write it again - this relies on the file being overwritten in place! */
if ( xpwrite(fd, boot_image, boot_image_len, 0) != boot_image_len ) {
fprintf(stderr, "%s: write failure on %s\n", program, file);
goto bail;
}
/* Attempt to set immutable flag and remove all write access */
/* Only set immutable flag if file is owned by root */
if ( !fstat(fd, &st) ) {
fchmod(fd, st.st_mode & (S_IRUSR|S_IRGRP|S_IROTH));
if ( st.st_uid == 0 && !ioctl(fd, EXT2_IOC_GETFLAGS, &flags) ) {
flags |= EXT2_IMMUTABLE_FL;
ioctl(fd, EXT2_IOC_SETFLAGS, &flags);
}
}
if ( fstat(fd, rst) ) {
perror(file);
goto bail;
}
close(dirfd);
close(fd);
return 0;
bail:
if ( dirfd >= 0 )
close(dirfd);
if ( fd >= 0 )
close(fd);
return 1;
}
int
install_loader(const char *path)
{
struct stat st, dst, fst;
struct mntent *mnt = NULL;
int devfd, rv;
FILE *mtab;
if ( stat(path, &st) || !S_ISDIR(st.st_mode) ) {
fprintf(stderr, "%s: Not a directory: %s\n", program, path);
return 1;
}
devfd = -1;
if ( (mtab = setmntent("/proc/mounts", "r")) ) {
while ( (mnt = getmntent(mtab)) ) {
if ( (!strcmp(mnt->mnt_type, "ext2") ||
!strcmp(mnt->mnt_type, "ext3")) &&
!stat(mnt->mnt_fsname, &dst) &&
dst.st_rdev == st.st_dev ) {
fprintf(stderr, "%s is device %s\n", path, mnt->mnt_fsname);
if ( (devfd = open(mnt->mnt_fsname, O_RDWR|O_SYNC)) < 0 ) {
fprintf(stderr, "%s: cannot open device %s\n", program, mnt->mnt_fsname);
return 1;
}
break;
}
}
}
if ( devfd < 0 ) {
/* Didn't find it in /proc/mounts, try /etc/mtab */
if ( (mtab = setmntent("/etc/mtab", "r")) ) {
while ( (mnt = getmntent(mtab)) ) {
if ( (!strcmp(mnt->mnt_type, "ext2") ||
!strcmp(mnt->mnt_type, "ext3")) &&
!stat(mnt->mnt_fsname, &dst) &&
dst.st_rdev == st.st_dev ) {
fprintf(stderr, "%s is device %s\n", path, mnt->mnt_fsname);
if ( (devfd = open(mnt->mnt_fsname, O_RDWR|O_SYNC)) < 0 ) {
fprintf(stderr, "%s: cannot open device %s\n", program, mnt->mnt_fsname);
return 1;
}
break;
}
}
}
}
if ( devfd < 0 ) {
fprintf(stderr, "%s: cannot find device for path %s\n", program, path);
return 1;
}
install_file(path, devfd, &fst);
if ( fst.st_dev != st.st_dev ) {
fprintf(stderr, "%s: file system changed under us - aborting!\n",
program);
return 1;
}
sync();
rv = install_bootblock(devfd, mnt->mnt_fsname);
close(devfd);
sync();
endmntent(mtab);
if ( rv ) return rv;
return 0;
}
int
main(int argc, char *argv[])
{
int o;
const char *directory;
program = argv[0];
while ( (o = getopt_long(argc, argv, short_options,
long_options, NULL)) != EOF ) {
switch ( o ) {
case 'z':
opt.heads = 64;
opt.sectors = 32;
break;
case 'S':
opt.sectors = strtoul(optarg, NULL, 0);
if ( opt.sectors < 1 || opt.sectors > 63 ) {
fprintf(stderr, "%s: invalid number of sectors: %u (must be 1-63)\n",
program, opt.sectors);
exit(EX_USAGE);
}
break;
case 'H':
opt.heads = strtoul(optarg, NULL, 0);
if ( opt.heads < 1 || opt.heads > 256 ) {
fprintf(stderr, "%s: invalid number of heads: %u (must be 1-256)\n",
program, opt.heads);
exit(EX_USAGE);
}
break;
case 'h':
usage(0);
break;
case 'v':
fputs("extlinux " VERSION "\n", stderr);
exit(0);
default:
fprintf(stderr, "%s: Unknown option: %c\n", program, optopt);
exit(EX_USAGE);
}
}
directory = argv[optind];
if ( !directory )
usage(EX_USAGE);
return install_loader(directory);
}