1 /* ----------------------------------------------------------------------- *
3 * Copyright 1998-2008 H. Peter Anvin - All Rights Reserved
4 * Copyright 2009 Intel Corporation; author: H. Peter Anvin
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, Inc., 53 Temple Place Ste 330,
9 * Boston MA 02111-1307, USA; either version 2 of the License, or
10 * (at your option) any later version; incorporated herein by reference.
12 * ----------------------------------------------------------------------- */
17 * Install the extlinux boot block on an ext2/3 filesystem
20 #define _GNU_SOURCE /* Enable everything */
22 /* This is needed to deal with the kernel headers imported into glibc 3.3.3. */
36 #include <sys/ioctl.h>
38 #include <sys/types.h>
39 #include <sys/mount.h>
42 #include <linux/fd.h> /* Floppy geometry */
43 #include <linux/hdreg.h> /* Hard disk geometry */
44 #define statfs _kernel_statfs /* HACK to deal with broken 2.4 distros */
45 #include <linux/fs.h> /* FIGETBSZ, FIBMAP */
49 #include "../version.h"
53 # define dprintf printf
55 # define dprintf(...) ((void)0)
58 /* Global option handling */
62 /* These are the options we can set and their values */
79 static void __attribute__((noreturn)) usage(int rv)
82 "Usage: %s [options] directory\n"
83 " --install -i Install over the current bootsector\n"
84 " --update -U Update a previous EXTLINUX installation\n"
85 " --zip -z Force zipdrive geometry (-H 64 -S 32)\n"
86 " --sectors=# -S Force the number of sectors per track\n"
87 " --heads=# -H Force number of heads\n"
88 " --stupid -s Slow, safe and stupid mode\n"
89 " --raid -r Fall back to the next device on boot failure\n"
90 " --once=... -o Execute a command once upon boot\n"
91 " --clear-once -O Clear the boot-once command\n"
92 " --reset-adv Reset auxilliary data\n"
94 " Note: geometry is determined at boot time for devices which\n"
95 " are considered hard disks by the BIOS. Unfortunately, this is\n"
96 " not possible for devices which are considered floppy disks,\n"
97 " which includes zipdisks and LS-120 superfloppies.\n"
99 " The -z option is useful for USB devices which are considered\n"
100 " hard disks by some BIOSes and zipdrives by other BIOSes.\n",
111 static const struct option long_options[] = {
112 { "install", 0, NULL, 'i' },
113 { "update", 0, NULL, 'U' },
114 { "zipdrive", 0, NULL, 'z' },
115 { "sectors", 1, NULL, 'S' },
116 { "stupid", 0, NULL, 's' },
117 { "heads", 1, NULL, 'H' },
118 { "raid-mode", 0, NULL, 'r' },
119 { "version", 0, NULL, 'v' },
120 { "help", 0, NULL, 'h' },
121 { "once", 1, NULL, 'o' },
122 { "clear-once", 0, NULL, 'O' },
123 { "reset-adv", 0, NULL, OPT_RESET_ADV },
127 static const char short_options[] = "iUuzS:H:rvho:O";
129 #if defined(__linux__) && !defined(BLKGETSIZE64)
130 /* This takes a u64, but the size field says size_t. Someone screwed big. */
131 # define BLKGETSIZE64 _IOR(0x12,114,size_t)
134 #ifndef EXT2_SUPER_OFFSET
135 #define EXT2_SUPER_OFFSET 1024
143 extern unsigned char extlinux_bootsect[];
144 extern unsigned int extlinux_bootsect_len;
145 #define boot_block extlinux_bootsect
146 #define boot_block_len extlinux_bootsect_len
151 extern unsigned char extlinux_image[];
152 extern unsigned int extlinux_image_len;
153 #define boot_image extlinux_image
154 #define boot_image_len extlinux_image_len
157 * Common abort function
159 void __attribute__((noreturn)) die(const char *msg)
166 * read/write wrapper functions
168 ssize_t xpread(int fd, void *buf, size_t count, off_t offset)
170 char *bufp = (char *)buf;
175 rv = pread(fd, bufp, count, offset);
178 } else if ( rv == -1 ) {
179 if ( errno == EINTR ) {
182 die(strerror(errno));
195 ssize_t xpwrite(int fd, const void *buf, size_t count, off_t offset)
197 const char *bufp = (const char *)buf;
202 rv = pwrite(fd, bufp, count, offset);
205 } else if ( rv == -1 ) {
206 if ( errno == EINTR ) {
209 die(strerror(errno));
226 sectmap(int fd, uint32_t *sectors, int nsectors)
228 unsigned int blksize, blk, nblk;
232 if ( ioctl(fd, FIGETBSZ, &blksize) )
235 /* Number of sectors per block */
236 blksize >>= SECTOR_SHIFT;
242 dprintf("querying block %u\n", blk);
243 if ( ioctl(fd, FIBMAP, &blk) )
247 for ( i = 0 ; i < blksize ; i++ ) {
251 dprintf("Sector: %10u\n", blk);
261 * Get the size of a block device
263 uint64_t get_size(int devfd)
270 if ( !ioctl(devfd, BLKGETSIZE64, &bytes) )
273 if ( !ioctl(devfd, BLKGETSIZE, §s) )
274 return (uint64_t)sects << 9;
275 else if ( !fstat(devfd, &st) && st.st_size )
283 * Get device geometry and partition offset
285 struct geometry_table {
287 struct hd_geometry g;
290 /* Standard floppy disk geometries, plus LS-120. Zipdisk geometry
291 (x/64/32) is the final fallback. I don't know what LS-240 has
292 as its geometry, since I don't have one and don't know anyone that does,
293 and Google wasn't helpful... */
294 static const struct geometry_table standard_geometries[] = {
295 { 360*1024, { 2, 9, 40, 0 } },
296 { 720*1024, { 2, 9, 80, 0 } },
297 { 1200*1024, { 2, 15, 80, 0 } },
298 { 1440*1024, { 2, 18, 80, 0 } },
299 { 1680*1024, { 2, 21, 80, 0 } },
300 { 1722*1024, { 2, 21, 80, 0 } },
301 { 2880*1024, { 2, 36, 80, 0 } },
302 { 3840*1024, { 2, 48, 80, 0 } },
303 { 123264*1024, { 8, 32, 963, 0 } }, /* LS120 */
308 get_geometry(int devfd, uint64_t totalbytes, struct hd_geometry *geo)
310 struct floppy_struct fd_str;
311 const struct geometry_table *gp;
313 memset(geo, 0, sizeof *geo);
315 if ( !ioctl(devfd, HDIO_GETGEO, &geo) ) {
317 } else if ( !ioctl(devfd, FDGETPRM, &fd_str) ) {
318 geo->heads = fd_str.head;
319 geo->sectors = fd_str.sect;
320 geo->cylinders = fd_str.track;
325 /* Didn't work. Let's see if this is one of the standard geometries */
326 for ( gp = standard_geometries ; gp->bytes ; gp++ ) {
327 if ( gp->bytes == totalbytes ) {
328 memcpy(geo, &gp->g, sizeof *geo);
333 /* Didn't work either... assign a geometry of 64 heads, 32 sectors; this is
334 what zipdisks use, so this would help if someone has a USB key that
335 they're booting in USB-ZIP mode. */
337 geo->heads = opt.heads ?: 64;
338 geo->sectors = opt.sectors ?: 32;
339 geo->cylinders = totalbytes/(geo->heads*geo->sectors << SECTOR_SHIFT);
342 if ( !opt.sectors && !opt.heads )
343 fprintf(stderr, "Warning: unable to obtain device geometry (defaulting to %d heads, %d sectors)\n"
344 " (on hard disks, this is usually harmless.)\n",
345 geo->heads, geo->sectors);
351 * Query the device geometry and put it into the boot sector.
352 * Map the file and put the map in the boot sector and file.
353 * Stick the "current directory" inode number into the file.
356 patch_file_and_bootblock(int fd, int dirfd, int devfd)
359 struct hd_geometry geo;
361 uint64_t totalbytes, totalsectors;
364 struct boot_sector *bs;
365 struct patch_area *patcharea;
369 if ( fstat(dirfd, &dirst) ) {
370 perror("fstat dirfd");
371 exit(255); /* This should never happen */
374 totalbytes = get_size(devfd);
375 get_geometry(devfd, totalbytes, &geo);
378 geo.heads = opt.heads;
380 geo.sectors = opt.sectors;
382 /* Patch this into a fake FAT superblock. This isn't because
383 FAT is a good format in any way, it's because it lets the
384 early bootstrap share code with the FAT version. */
385 dprintf("heads = %u, sect = %u\n", geo.heads, geo.sectors);
387 bs = (struct boot_sector *)boot_block;
389 totalsectors = totalbytes >> SECTOR_SHIFT;
390 if ( totalsectors >= 65536 ) {
391 set_16(&bs->bsSectors, 0);
393 set_16(&bs->bsSectors, totalsectors);
395 set_32(&bs->bsHugeSectors, totalsectors);
397 set_16(&bs->bsBytesPerSec, SECTOR_SIZE);
398 set_16(&bs->bsSecPerTrack, geo.sectors);
399 set_16(&bs->bsHeads, geo.heads);
400 set_32(&bs->bsHiddenSecs, geo.start);
402 /* If we're in RAID mode then patch the appropriate instruction;
403 either way write the proper boot signature */
404 i = get_16(&bs->bsSignature);
406 set_16((uint16_t *)(boot_block+i), 0x18CD); /* INT 18h */
408 set_16(&bs->bsSignature, 0xAA55);
410 /* Construct the boot file */
412 dprintf("directory inode = %lu\n", (unsigned long) dirst.st_ino);
413 nsect = (boot_image_len+SECTOR_SIZE-1) >> SECTOR_SHIFT;
414 nsect += 2; /* Two sectors for the ADV */
415 sectp = alloca(sizeof(uint32_t)*nsect);
416 if ( sectmap(fd, sectp, nsect) ) {
421 /* First sector need pointer in boot sector */
422 set_32(&bs->NextSector, *sectp++);
426 set_16(&bs->MaxTransfer, 1);
428 /* Search for LDLINUX_MAGIC to find the patch area */
429 for (wp = (uint32_t *)boot_image; get_32(wp) != LDLINUX_MAGIC; wp++);
430 patcharea = (struct patch_area *)wp;
432 /* Set up the totals */
433 dw = boot_image_len >> 2; /* COMPLETE dwords, excluding ADV */
434 set_16(&patcharea->data_sectors, nsect-2); /* -2 for the ADVs */
435 set_16(&patcharea->adv_sectors, 2);
436 set_32(&patcharea->dwords, dw);
437 set_32(&patcharea->currentdir, dirst.st_ino);
439 /* Set the sector pointers */
440 wp = (uint32_t *)((char *)boot_image+get_16(&patcharea->secptroffset));
441 nptrs = get_16(&patcharea->secptrcnt);
443 memset(wp, 0, nptrs*4);
445 set_32(wp++, *sectp++);
447 /* Now produce a checksum */
448 set_32(&patcharea->checksum, 0);
450 csum = LDLINUX_MAGIC;
451 for (i = 0, wp = (uint32_t *)boot_image; i < dw; i++, wp++)
452 csum -= get_32(wp); /* Negative checksum */
454 set_32(&patcharea->checksum, csum);
458 * Read the ADV from an existing instance, or initialize if invalid.
459 * Returns -1 on fatal errors, 0 if ADV is okay, and 1 if no valid
463 read_adv(const char *path)
470 asprintf(&file, "%s%sextlinux.sys",
472 path[0] && path[strlen(path)-1] == '/' ? "" : "/");
479 fd = open(file, O_RDONLY);
481 if ( errno != ENOENT ) {
484 syslinux_reset_adv(syslinux_adv);
486 } else if (fstat(fd, &st)) {
488 } else if (st.st_size < 2*ADV_SIZE) {
489 /* Too small to be useful */
490 syslinux_reset_adv(syslinux_adv);
491 err = 0; /* Nothing to read... */
492 } else if (xpread(fd, syslinux_adv, 2*ADV_SIZE,
493 st.st_size-2*ADV_SIZE) != 2*ADV_SIZE) {
496 /* We got it... maybe? */
497 err = syslinux_validate_adv(syslinux_adv) ? 1 : 0;
512 * Update the ADV in an existing installation.
515 write_adv(const char *path)
517 unsigned char advtmp[2*ADV_SIZE];
524 asprintf(&file, "%s%sextlinux.sys",
526 path[0] && path[strlen(path)-1] == '/' ? "" : "/");
533 fd = open(file, O_RDONLY);
536 } else if (fstat(fd, &st)) {
538 } else if (st.st_size < 2*ADV_SIZE) {
539 /* Too small to be useful */
541 } else if (xpread(fd, advtmp, 2*ADV_SIZE,
542 st.st_size-2*ADV_SIZE) != 2*ADV_SIZE) {
545 /* We got it... maybe? */
546 err = syslinux_validate_adv(advtmp) ? -2 : 0;
548 /* Got a good one, write our own ADV here */
549 if (!ioctl(fd, EXT2_IOC_GETFLAGS, &flags)) {
550 nflags = flags & ~EXT2_IMMUTABLE_FL;
552 ioctl(fd, EXT2_IOC_SETFLAGS, &nflags);
554 if (!(st.st_mode & S_IWUSR))
555 fchmod(fd, st.st_mode | S_IWUSR);
557 /* Need to re-open read-write */
559 fd = open(file, O_RDWR|O_SYNC);
562 } else if (fstat(fd, &xst) || xst.st_ino != st.st_ino ||
563 xst.st_dev != st.st_dev || xst.st_size != st.st_size) {
564 fprintf(stderr, "%s: race condition on write\n", file);
567 /* Write our own version ... */
568 if (xpwrite(fd, syslinux_adv, 2*ADV_SIZE,
569 st.st_size-2*ADV_SIZE) != 2*ADV_SIZE) {
575 if (!(st.st_mode & S_IWUSR))
576 fchmod(fd, st.st_mode);
579 ioctl(fd, EXT2_IOC_SETFLAGS, &flags);
584 fprintf(stderr, "%s: cannot write auxilliary data (need --update)?\n",
598 * Make any user-specified ADV modifications
605 if (syslinux_setadv(ADV_BOOTONCE, strlen(opt.set_once), opt.set_once)) {
606 fprintf(stderr, "%s: not enough space for boot-once command\n", program);
615 * Install the boot block on the specified device.
616 * Must be run AFTER install_file()!
619 install_bootblock(int fd, const char *device)
621 struct ext2_super_block sb;
623 if ( xpread(fd, &sb, sizeof sb, EXT2_SUPER_OFFSET) != sizeof sb ) {
624 perror("reading superblock");
628 if ( sb.s_magic != EXT2_SUPER_MAGIC ) {
629 fprintf(stderr, "no ext2/ext3 superblock found on %s\n", device);
633 if ( xpwrite(fd, boot_block, boot_block_len, 0) != boot_block_len ) {
634 perror("writing bootblock");
642 install_file(const char *path, int devfd, struct stat *rst)
645 int fd = -1, dirfd = -1, flags;
648 asprintf(&file, "%s%sextlinux.sys",
650 path[0] && path[strlen(path)-1] == '/' ? "" : "/");
656 dirfd = open(path, O_RDONLY|O_DIRECTORY);
662 fd = open(file, O_RDONLY);
664 if ( errno != ENOENT ) {
669 /* If file exist, remove the immutable flag and set u+w mode */
670 if ( !ioctl(fd, EXT2_IOC_GETFLAGS, &flags) ) {
671 flags &= ~EXT2_IMMUTABLE_FL;
672 ioctl(fd, EXT2_IOC_SETFLAGS, &flags);
674 if ( !fstat(fd, &st) ) {
675 fchmod(fd, st.st_mode | S_IWUSR);
680 fd = open(file, O_WRONLY|O_TRUNC|O_CREAT|O_SYNC, S_IRUSR|S_IRGRP|S_IROTH);
686 /* Write it the first time */
687 if ( xpwrite(fd, boot_image, boot_image_len, 0) != boot_image_len ||
688 xpwrite(fd, syslinux_adv, 2*ADV_SIZE, boot_image_len) != 2*ADV_SIZE ) {
689 fprintf(stderr, "%s: write failure on %s\n", program, file);
693 /* Map the file, and patch the initial sector accordingly */
694 patch_file_and_bootblock(fd, dirfd, devfd);
696 /* Write the first sector again - this relies on the file being
697 overwritten in place! */
698 if ( xpwrite(fd, boot_image, SECTOR_SIZE, 0) != SECTOR_SIZE ) {
699 fprintf(stderr, "%s: write failure on %s\n", program, file);
703 /* Attempt to set immutable flag and remove all write access */
704 /* Only set immutable flag if file is owned by root */
705 if ( !fstat(fd, &st) ) {
706 fchmod(fd, st.st_mode & (S_IRUSR|S_IRGRP|S_IROTH));
707 if ( st.st_uid == 0 && !ioctl(fd, EXT2_IOC_GETFLAGS, &flags) ) {
708 flags |= EXT2_IMMUTABLE_FL;
709 ioctl(fd, EXT2_IOC_SETFLAGS, &flags);
713 if ( fstat(fd, rst) ) {
731 /* EXTLINUX installs the string 'EXTLINUX' at offset 3 in the boot
732 sector; this is consistent with FAT filesystems. */
734 already_installed(int devfd)
738 xpread(devfd, buffer, 8, 3);
739 return !memcmp(buffer, "EXTLINUX", 8);
744 static char devname_buf[64];
746 static void device_cleanup(void)
752 /* Verify that a device fd and a pathname agree.
753 Return 0 on valid, -1 on error. */
754 static int validate_device(const char *path, int devfd)
756 struct stat pst, dst;
758 if (stat(path, &pst) || fstat(devfd, &dst))
761 return (pst.st_dev == dst.st_rdev) ? 0 : -1;
765 static const char *find_device(const char *mtab_file, dev_t dev)
770 const char *devname = NULL;
772 mtab = setmntent(mtab_file, "r");
776 while ( (mnt = getmntent(mtab)) ) {
777 if ( (!strcmp(mnt->mnt_type, "ext2") ||
778 !strcmp(mnt->mnt_type, "ext3")) &&
779 !stat(mnt->mnt_fsname, &dst) && dst.st_rdev == dev ) {
780 devname = strdup(mnt->mnt_fsname);
791 install_loader(const char *path, int update_only)
795 const char *devname = NULL;
798 if ( stat(path, &st) || !S_ISDIR(st.st_mode) ) {
799 fprintf(stderr, "%s: Not a directory: %s\n", program, path);
803 if ( statfs(path, &sfs) ) {
804 fprintf(stderr, "%s: statfs %s: %s\n", program, path, strerror(errno));
808 if ( sfs.f_type != EXT2_SUPER_MAGIC ) {
809 fprintf(stderr, "%s: not an ext2/ext3 filesystem: %s\n", program, path);
817 /* klibc doesn't have getmntent and friends; instead, just create
818 a new device with the appropriate device type */
819 snprintf(devname_buf, sizeof devname_buf, "/tmp/dev-%u:%u",
820 major(st.st_dev), minor(st.st_dev));
822 if (mknod(devname_buf, S_IFBLK|0600, st.st_dev)) {
823 fprintf(stderr, "%s: cannot create device %s\n", program, devname);
827 atexit(device_cleanup); /* unlink the device node on exit */
828 devname = devname_buf;
832 devname = find_device("/proc/mounts", st.st_dev);
834 /* Didn't find it in /proc/mounts, try /etc/mtab */
835 devname = find_device("/etc/mtab", st.st_dev);
838 fprintf(stderr, "%s: cannot find device for path %s\n", program, path);
842 fprintf(stderr, "%s is device %s\n", path, devname);
845 if ( (devfd = open(devname, O_RDWR|O_SYNC)) < 0 ) {
846 fprintf(stderr, "%s: cannot open device %s\n", program, devname);
850 /* Verify that the device we opened is the device intended */
851 if (validate_device(path, devfd)) {
852 fprintf(stderr, "%s: path %s doesn't match device %s\n",
853 program, path, devname);
857 if ( update_only && !already_installed(devfd) ) {
858 fprintf(stderr, "%s: no previous extlinux boot sector found\n", program);
862 /* Read a pre-existing ADV, if already installed */
864 syslinux_reset_adv(syslinux_adv);
865 else if (read_adv(path) < 0)
868 if (modify_adv() < 0)
871 /* Install extlinux.sys */
872 if (install_file(path, devfd, &fst))
875 if ( fst.st_dev != st.st_dev ) {
876 fprintf(stderr, "%s: file system changed under us - aborting!\n",
882 rv = install_bootblock(devfd, devname);
890 * Modify the ADV of an existing installation
893 modify_existing_adv(const char *path)
896 syslinux_reset_adv(syslinux_adv);
897 else if (read_adv(path) < 0)
900 if (modify_adv() < 0)
903 if (write_adv(path) < 0)
910 main(int argc, char *argv[])
913 const char *directory;
914 int update_only = -1;
918 while ( (o = getopt_long(argc, argv, short_options,
919 long_options, NULL)) != EOF ) {
926 opt.sectors = strtoul(optarg, NULL, 0);
927 if ( opt.sectors < 1 || opt.sectors > 63 ) {
928 fprintf(stderr, "%s: invalid number of sectors: %u (must be 1-63)\n",
929 program, opt.sectors);
934 opt.heads = strtoul(optarg, NULL, 0);
935 if ( opt.heads < 1 || opt.heads > 256 ) {
936 fprintf(stderr, "%s: invalid number of heads: %u (must be 1-256)\n",
958 opt.set_once = optarg;
967 fputs("extlinux " VERSION_STR
968 " Copyright 1994-" YEAR_STR " H. Peter Anvin \n", stderr);
975 directory = argv[optind];
980 if ( update_only == -1 ) {
981 if (opt.reset_adv || opt.set_once) {
982 return modify_existing_adv(directory);
988 return install_loader(directory, update_only);