1 /* ----------------------------------------------------------------------- *
3 * Copyright 1998-2008 H. Peter Anvin - All Rights Reserved
4 * Copyright 2009-2010 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 * ----------------------------------------------------------------------- */
15 * syslinux.c - Linux installer program for SYSLINUX
36 char *program = "syslinux.com"; /* Name of program */
40 # define dprintf printf
45 asm volatile("int $0x16" : "=a" (ax) : "a" (0));
48 # define dprintf(...) ((void)0)
49 # define pause() ((void)0)
52 void unlock_device(int);
54 void __attribute__ ((noreturn)) die(const char *msg)
63 void warning(const char *msg)
65 puts("syslinux: warning: ");
71 * read/write wrapper functions
73 int creat(const char *filename, int mode)
78 dprintf("creat(\"%s\", 0x%x)\n", filename, mode);
81 asm volatile ("int $0x21 ; setc %0"
82 : "=bcdm" (err), "+a" (rv)
83 : "c" (mode), "d" (filename));
85 dprintf("rv = %d\n", rv);
86 die("cannot open ldlinux.sys");
96 dprintf("close(%d)\n", fd);
98 asm volatile ("int $0x21":"+a" (rv)
101 /* The only error MS-DOS returns for close is EBADF,
102 and we really don't care... */
105 int rename(const char *oldname, const char *newname)
107 uint16_t rv = 0x5600; /* Also support 43FFh? */
110 dprintf("rename(\"%s\", \"%s\")\n", oldname, newname);
112 asm volatile ("int $0x21 ; setc %0":"=bcdm" (err), "+a"(rv)
113 :"d"(oldname), "D"(newname));
116 dprintf("rv = %d\n", rv);
117 warning("cannot move ldlinux.sys");
124 ssize_t write_ldlinux(int fd)
126 uint16_t ldlinux_seg = ((size_t)syslinux_ldlinux >> 4) + ds();
131 while (offset < syslinux_ldlinux_len) {
132 uint32_t chunk = syslinux_ldlinux_len - offset;
135 asm volatile ("pushw %%ds ; "
138 "popw %%ds ; " "setc %0":"=bcdm" (err), "=a"(rv)
139 :"a"(0x4000), "b"(fd), "c"(chunk), "d" (offset & 15),
140 "SD" ((uint16_t)(ldlinux_seg + (offset >> 4))));
142 die("file write error");
149 ssize_t write_file(int fd, const void *buf, size_t count)
155 dprintf("write_file(%d,%p,%u)\n", fd, buf, count);
158 asm volatile ("int $0x21 ; setc %0":"=bcdm" (err), "=a"(rv)
159 :"a"(0x4000), "b"(fd), "c"(count), "d"(buf));
161 die("file write error");
170 static inline __attribute__ ((const))
171 uint16_t data_segment(void)
175 asm("movw %%ds,%0" : "=rm"(ds));
179 void write_device(int drive, const void *buf, size_t nsecs, unsigned int sector)
181 uint16_t errnum = 0x0001;
184 dprintf("write_device(%d,%p,%u,%u)\n", drive, buf, nsecs, sector);
186 dio.startsector = sector;
188 dio.bufoffs = (uintptr_t) buf;
189 dio.bufseg = data_segment();
191 if (dos_version >= 0x070a) {
192 /* Try FAT32-aware system call first */
193 asm volatile("int $0x21 ; jc 1f ; xorw %0,%0\n"
196 : "a" (0x7305), "b" (&dio), "c" (-1), "d" (drive),
199 dprintf(" rv(7305) = %04x", errnum);
202 /* If not supported, try the legacy system call (int2526.S) */
203 if (errnum == 0x0001)
204 errnum = int26_write_sector(drive, &dio);
207 dprintf("rv = %04x\n", errnum);
208 die("sector write error");
212 void read_device(int drive, void *buf, size_t nsecs, unsigned int sector)
214 uint16_t errnum = 0x0001;
217 dprintf("read_device(%d,%p,%u,%u)\n", drive, buf, nsecs, sector);
219 dio.startsector = sector;
221 dio.bufoffs = (uintptr_t) buf;
222 dio.bufseg = data_segment();
224 if (dos_version >= 0x070a) {
225 /* Try FAT32-aware system call first */
226 asm volatile("int $0x21 ; jc 1f ; xorw %0,%0\n"
229 : "a" (0x7305), "b" (&dio), "c" (-1), "d" (drive),
231 dprintf(" rv(7305) = %04x", errnum);
234 /* If not supported, try the legacy system call (int2526.S) */
235 if (errnum == 0x0001)
236 errnum = int25_read_sector(drive, &dio);
239 dprintf("rv = %04x\n", errnum);
240 die("sector read error");
244 /* Both traditional DOS and FAT32 DOS return this structure, but
245 FAT32 return a lot more data, so make sure we have plenty of space */
246 struct deviceparams {
252 uint16_t bytespersec;
256 uint16_t rootdirents;
260 uint16_t secpertrack;
263 uint32_t hugesectors;
264 uint8_t lotsofpadding[224];
265 } __attribute__ ((packed));
267 uint32_t get_partition_offset(int drive)
271 struct deviceparams dp;
273 dp.specfunc = 1; /* Get current information */
276 asm volatile ("int $0x21 ; setc %0"
277 :"=abcdm" (err), "+a"(rv), "=m"(dp)
278 :"b" (drive), "c" (0x0860), "d" (&dp));
281 return dp.hiddensecs;
284 asm volatile ("int $0x21 ; setc %0"
285 : "=abcdm" (err), "+a" (rv), "=m" (dp)
286 : "b" (drive), "c" (0x4860), "d" (&dp));
289 return dp.hiddensecs;
291 die("could not find partition start offset");
298 uint16_t firstsector;
300 uint16_t bufferoffset;
302 } __attribute__ ((packed));
304 static struct rwblock mbr = {
308 .firstsector = 0, /* MS-DOS, unlike the BIOS, zero-base sectors */
314 void write_mbr(int drive, const void *buf)
319 dprintf("write_mbr(%d,%p)", drive, buf);
321 mbr.bufferoffset = (uintptr_t) buf;
322 mbr.bufferseg = data_segment();
325 asm volatile ("int $0x21 ; setc %0" : "=bcdm" (err), "+a"(rv)
326 :"c"(0x0841), "d"(&mbr), "b"(drive), "m"(mbr));
328 dprintf(" rv(0841) = %04x", rv);
335 asm volatile ("int $0x21 ; setc %0" : "=bcdm" (err), "+a"(rv)
336 :"c"(0x4841), "d"(&mbr), "b"(drive), "m"(mbr));
338 dprintf(" rv(4841) = %04x\n", rv);
340 die("mbr write error");
343 void read_mbr(int drive, const void *buf)
348 dprintf("read_mbr(%d,%p)", drive, buf);
350 mbr.bufferoffset = (uintptr_t) buf;
351 mbr.bufferseg = data_segment();
354 asm volatile ("int $0x21 ; setc %0":"=abcdm" (err), "+a"(rv)
355 :"c"(0x0861), "d"(&mbr), "b"(drive), "m"(mbr));
357 dprintf(" rv(0861) = %04x", rv);
364 asm volatile ("int $0x21 ; setc %0":"=abcdm" (err), "+a"(rv)
365 :"c"(0x4861), "d"(&mbr), "b"(drive), "m"(mbr));
367 dprintf(" rv(4841) = %04x\n", rv);
369 die("mbr read error");
371 dprintf("Bytes: %02x %02x %02x %02x %02x %02x %02x %02x\n",
372 ((const uint8_t *)buf)[0],
373 ((const uint8_t *)buf)[1],
374 ((const uint8_t *)buf)[2],
375 ((const uint8_t *)buf)[3],
376 ((const uint8_t *)buf)[4],
377 ((const uint8_t *)buf)[5],
378 ((const uint8_t *)buf)[6],
379 ((const uint8_t *)buf)[7]);
382 /* This call can legitimately fail, and we don't care, so ignore error return */
383 void set_attributes(const char *file, int attributes)
385 uint16_t rv = 0x4301;
387 dprintf("set_attributes(\"%s\", 0x%02x)\n", file, attributes);
389 asm volatile ("int $0x21":"+a" (rv)
390 :"c"(attributes), "d"(file));
394 * Version of the read_device function suitable for libfat
396 int libfat_xpread(intptr_t pp, void *buf, size_t secsize,
397 libfat_sector_t sector)
399 read_device(pp, buf, 1, sector);
403 static inline void get_dos_version(void)
407 asm("int $0x21 ; xchgb %%ah,%%al"
413 dprintf("DOS version %d.%d\n", (dos_version >> 8), dos_version & 0xff);
416 /* The locking interface relies on static variables. A massive hack :( */
417 static uint8_t lock_level, lock_drive;
419 static inline void set_lock_device(uint8_t device)
425 static int do_lock(uint8_t level)
427 uint16_t level_arg = lock_drive + (level << 8);
431 /* DOS 7.10 = Win95 OSR2 = first version with FAT32 */
432 uint16_t lock_call = (dos_version >= 0x070a) ? 0x484A : 0x084A;
434 uint16_t lock_call = 0x084A; /* MSDN says this is OK for all filesystems */
437 dprintf("Trying lock %04x... ", level_arg);
438 asm volatile ("int $0x21 ; setc %0"
439 : "=bcdm" (err), "=a" (rv)
440 : "a" (0x440d), "b" (level_arg),
441 "c" (lock_call), "d" (0x0001));
442 dprintf("%s %04x\n", err ? "err" : "ok", rv);
447 void lock_device(int level)
449 static int hard_lock = 0;
452 if (dos_version < 0x0700)
453 return; /* Win9x/NT only */
456 /* Assume hierarchial "soft" locking supported */
458 while (lock_level < level) {
459 int new_level = lock_level + 1;
460 err = do_lock(new_level);
463 /* Try hard locking next */
469 lock_level = new_level;
476 /* Hard locking, only level 4 supported */
477 /* This is needed for Win9x in DOS mode */
482 /* Assume locking is not needed */
493 die("could not lock device");
496 void unlock_device(int level)
500 uint16_t unlock_call;
502 if (dos_version < 0x0700)
503 return; /* Win9x/NT only */
506 /* DOS 7.10 = Win95 OSR2 = first version with FAT32 */
507 unlock_call = (dos_version >= 0x070a) ? 0x486A : 0x086A;
509 unlock_call = 0x086A; /* MSDN says this is OK for all filesystems */
512 if (lock_level == 4 && level > 0)
513 return; /* Only drop the hard lock at the end */
515 while (lock_level > level) {
516 uint8_t new_level = (lock_level == 4) ? 0 : lock_level - 1;
517 uint16_t level_arg = (new_level << 8) + lock_drive;
519 dprintf("Trying unlock %04x... ", new_level);
520 asm volatile ("int $0x21 ; setc %0"
521 : "=bcdm" (err), "+a" (rv)
522 : "b" (level_arg), "c" (unlock_call));
523 dprintf("%s %04x\n", err ? "err" : "ok", rv);
524 lock_level = new_level;
529 * This function does any desired MBR manipulation; called with the device lock held.
532 uint8_t active; /* Active flag */
533 uint8_t bhead; /* Begin head */
534 uint8_t bsector; /* Begin sector */
535 uint8_t bcylinder; /* Begin cylinder */
536 uint8_t filesystem; /* Filesystem value */
537 uint8_t ehead; /* End head */
538 uint8_t esector; /* End sector */
539 uint8_t ecylinder; /* End cylinder */
540 uint32_t startlba; /* Start sector LBA */
541 uint32_t sectors; /* Length in sectors */
542 } __attribute__ ((packed));
544 static void adjust_mbr(int device, int writembr, int set_active)
546 static unsigned char sectbuf[SECTOR_SIZE];
549 if (!writembr && !set_active)
550 return; /* Nothing to do */
552 read_mbr(device, sectbuf);
555 memcpy(sectbuf, syslinux_mbr, syslinux_mbr_len);
556 *(uint16_t *) (sectbuf + 510) = 0xaa55;
560 uint32_t offset = get_partition_offset(device);
561 struct mbr_entry *me = (struct mbr_entry *)(sectbuf + 446);
564 dprintf("Searching for partition offset: %08x\n", offset);
566 for (i = 0; i < 4; i++) {
567 if (me->startlba == offset) {
577 die("partition not found (-a is not implemented for logical partitions)");
578 } else if (found > 1) {
579 die("multiple aliased partitions found");
583 write_mbr(device, sectbuf);
586 int main(int argc, char *argv[])
588 static unsigned char sectbuf[SECTOR_SIZE];
590 static char ldlinux_name[] = "@:\\ldlinux.sys";
591 struct libfat_filesystem *fs;
592 libfat_sector_t s, *secp;
593 libfat_sector_t *sectors;
595 int32_t ldlinux_cluster;
602 dprintf("argv = %p\n", argv);
603 for (i = 0; i <= argc; i++)
604 dprintf("argv[%d] = %p = \"%s\"\n", i, argv[i], argv[i]);
609 parse_options(argc, argv, MODE_SYSLINUX_DOSWIN);
612 usage(EX_USAGE, MODE_SYSLINUX_DOSWIN);
613 if (opt.sectors || opt.heads || opt.reset_adv || opt.set_once
614 || (opt.update_only > 0) || opt.menu_save || opt.offset) {
616 "At least one specified option not yet implemented"
617 " for this installer.\n");
622 * Create an ADV in memory... this should be smarter.
624 syslinux_reset_adv(syslinux_adv);
627 * Figure out which drive we're talking to
629 dev_fd = (opt.device[0] & ~0x20) - 0x40;
630 if (dev_fd < 1 || dev_fd > 26 || opt.device[1] != ':' || opt.device[2])
631 usage(EX_USAGE, MODE_SYSLINUX_DOSWIN);
633 set_lock_device(dev_fd);
635 lock_device(2); /* Make sure we can lock the device */
636 read_device(dev_fd, sectbuf, 1, 0);
640 * Check to see that what we got was indeed an MS-DOS boot sector/superblock
642 if ((errmsg = syslinux_check_bootsect(sectbuf, NULL))) {
649 ldlinux_name[0] = dev_fd | 0x40;
651 set_attributes(ldlinux_name, 0);
652 fd = creat(ldlinux_name, 0); /* SYSTEM HIDDEN READONLY */
654 write_file(fd, syslinux_adv, 2 * ADV_SIZE);
656 set_attributes(ldlinux_name, 0x07); /* SYSTEM HIDDEN READONLY */
659 * Now, use libfat to create a block map. This probably
660 * should be changed to use ioctl(...,FIBMAP,...) since
661 * this is supposed to be a simple, privileged version
664 ldlinux_sectors = (syslinux_ldlinux_len + 2 * ADV_SIZE
665 + SECTOR_SIZE - 1) >> SECTOR_SHIFT;
666 sectors = calloc(ldlinux_sectors, sizeof *sectors);
668 fs = libfat_open(libfat_xpread, dev_fd);
669 ldlinux_cluster = libfat_searchdir(fs, 0, "LDLINUX SYS", NULL);
672 s = libfat_clustertosector(fs, ldlinux_cluster);
673 while (s && nsectors < ldlinux_sectors) {
676 s = libfat_nextsector(fs, s);
681 * If requested, move ldlinux.sys
684 char new_ldlinux_name[160];
685 char *cp = new_ldlinux_name + 3;
689 new_ldlinux_name[0] = dev_fd | 0x40;
690 new_ldlinux_name[1] = ':';
691 new_ldlinux_name[2] = '\\';
693 for (sd = opt.directory; *sd; sd++) {
696 if (c == '/' || c == '\\') {
708 /* Skip if subdirectory == root */
709 if (cp > new_ldlinux_name + 3) {
713 memcpy(cp, "ldlinux.sys", 12);
715 set_attributes(ldlinux_name, 0);
716 if (rename(ldlinux_name, new_ldlinux_name))
717 set_attributes(ldlinux_name, 0x07);
719 set_attributes(new_ldlinux_name, 0x07);
724 * Patch ldlinux.sys and the boot sector
726 i = syslinux_patch(sectors, nsectors, opt.stupid_mode, opt.raid_mode, opt.directory, NULL);
727 patch_sectors = (i + SECTOR_SIZE - 1) >> SECTOR_SHIFT;
730 * Overwrite the now-patched ldlinux.sys
732 /* lock_device(3); -- doesn't seem to be needed */
733 dp = syslinux_ldlinux;
734 for (i = 0; i < patch_sectors; i++) {
735 memcpy_from_sl(sectbuf, dp, SECTOR_SIZE);
737 write_device(dev_fd, sectbuf, 1, sectors[i]);
741 * Muck with the MBR, if desired, while we hold the lock
743 adjust_mbr(dev_fd, opt.install_mbr, opt.activate_partition);
746 * To finish up, write the boot sector
749 /* Read the superblock again since it might have changed while mounted */
750 read_device(dev_fd, sectbuf, 1, 0);
752 /* Copy the syslinux code into the boot sector */
753 syslinux_make_bootsect(sectbuf, VFAT);
755 /* Write new boot sector */
756 if (opt.bootsecfile) {
758 fd = creat(opt.bootsecfile, 0x20); /* ARCHIVE */
759 write_file(fd, sectbuf, SECTOR_SIZE);
762 write_device(dev_fd, sectbuf, 1, 0);