text: /*
   * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   *
   * Copyright (c) 2008 Luigi Rizzo
   * Copyright (c) 1999 Robert Nordier
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
   * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
   * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
   * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
   * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
   * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
   * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #if HAVE_NBTOOL_CONFIG_H
  #include "nbtool_config.h"
  #endif
  
  #include <sys/cdefs.h>
  /* __FBSDID("$FreeBSD$"); */
  
  #include <sys/param.h>
  #include <sys/stat.h>
  
  #if HAVE_NBTOOL_CONFIG_H
  #include <nbinclude/sys/disklabel.h>
  #include <nbinclude/sys/diskmbr.h>
  #else
  #include <sys/disklabel.h>
  #include <sys/diskmbr.h>
  #endif
  #include <err.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <paths.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  #include <fstab.h>
  #include <util.h>
  
  #define MBRSIZE         512     /* master boot record size */
  
  #define OFF_VERSION		0x1b0	/* offset: version number, only boot0version */
  #define OFF_SERIAL		0x1b8	/* offset: volume serial number */
  #define OFF_PTBL        0x1be   /* offset: partition table */
  #define OFF_MAGIC       0x1fe   /* offset: magic number */
  /*
   * Offsets to the parameters of the 512-byte boot block.
   * For historical reasons they are set as macros
   */
  struct opt_offsets {
  	int opt;
  	int drive;
  	int flags;
  	int ticks;
  };
  
  static struct opt_offsets b0_ofs[] = {
  	{ 0x0, 0x0, 0x0, 0x0 },			/* no boot block */
  	{ 0x1b9, 0x1ba, 0x1bb, 0x1bc },	/* original block */
  	{ 0x1b5, 0x1b6, 0x1b7, 0x1bc },	/* NT_SERIAL block */
  };
  
  static int b0_ver;	/* boot block version set by boot0bs */
  
  #define OFF_OPT		(b0_ofs[b0_ver].opt)	/* default boot option */
  #define OFF_DRIVE	(b0_ofs[b0_ver].drive)	/* setdrv drive */
  #define OFF_FLAGS   (b0_ofs[b0_ver].flags)	/* option flags */
  #define OFF_TICKS   (b0_ofs[b0_ver].ticks)	/* clock ticks */
  
  #define cv2(p)  	((p)[0] | (p)[1] << 010)
  #define NELEM(x)	(sizeof(x)/sizeof((x)[0]))
  
  #define mk2(p, x)                               \
      (p)[0] = (u_int8_t)(x),                     \
      (p)[1] = (u_int8_t)((x) >> 010)
  
  static const struct {
      const char *tok;
      int def;
  } opttbl[] = {
      {"packet", 0},
      {"update", 1},
      {"setdrv", 0}
  };
  static const int nopt = NELEM(opttbl);
  
  static const char fmt0[] = "#   flag     start chs   type"
      "       end chs       offset         size\n";
  
  static const char fmt1[] = "%d   0x%02x   %4u:%3u:%2u   0x%02x"
      "   %4u:%3u:%2u   %10u   %10u\n";
  
  static int 	read_mbr(const char *, u_int8_t **, int);
  static void write_mbr(const char *, int, u_int8_t *, int, int);
  static void display_mbr(u_int8_t *);
  static int 	boot0version(const u_int8_t *);
  static int 	boot0bs(const u_int8_t *);
  static void stropt(const char *, int *, int *);
  static int 	argtoi(const char *, int, int, int);
  static int 	set_bell(u_int8_t *, int, int);
  static void usage(void);
  
  static unsigned vol_id[5];	/* 4 plus 1 for flag */
  
  static int v_flag;
  
  /*
   * Boot manager installation/configuration utility.
   */
  int
  main(int argc, char *argv[])
  {
      u_int8_t *mbr, *boot0;
      int boot0_size, mbr_size;
      const char *bpath, *fpath;
      char *disk;
      int B_flag, o_flag;
      int d_arg, m_arg, s_arg, t_arg;
      int o_and, o_or, o_e = -1;
      int up, c;
  
      bpath = "/boot/boot0";
      fpath = NULL;
      B_flag = v_flag = o_flag = 0;
      d_arg = m_arg = s_arg = t_arg = -1;
      o_and = 0xff;
      o_or = 0;
  	while ((c = getopt(argc, argv, "Bvb:d:e:f:i:m:o:s:t:")) != -1)
  		switch (c) {
  		case 'B':
  			B_flag = 1;
  			break;
  		case 'v':
  			v_flag = 1;
  			break;
  		case 'b':
  			bpath = optarg;
  			break;
  		case 'd':
  			d_arg = argtoi(optarg, 0, 0xff, 'd');
  			break;
  		case 'e':
  			if (optarg[0] == '0' && optarg[1] == 'x')
  				sscanf(optarg, "0x%02x", &o_e);
  			else
  				o_e = optarg[0];
  			break;
  		case 'f':
  			fpath = optarg;
  			break;
  		case 'i':
  			if (sscanf(optarg, "%02x%02x-%02x%02x", vol_id, vol_id + 1,
  					vol_id + 2, vol_id + 3) == 4)
  				vol_id[4] = 1;
  			else
  				errx(1, "bad argument %s", optarg);
  			break;
  		case 'm':
  			m_arg = argtoi(optarg, 0, 0xf, 'm');
  			break;
  		case 'o':
  			stropt(optarg, &o_and, &o_or);
  			o_flag = 1;
  			break;
  		case 's':
  			if (strcasecmp(optarg, "pxe") == 0)
  				s_arg = 6;
  			else
  				s_arg = argtoi(optarg, 1, 6, 's');
  			break;
  		case 't':
  			t_arg = argtoi(optarg, 1, 0xffff, 't');
  			break;
  		default:
  			usage();
  		}
  	argc -= optind;
  	argv += optind;
  	if (argc != 1)
  		usage();
  	disk = getdevpath(*argv, 0);
  	if (disk == NULL)
  		err(1, "cannot open disk %s", disk);
  
  	up = B_flag || d_arg != -1 || m_arg != -1 || o_flag || s_arg != -1
  			|| t_arg != -1;
  
  	/* open the disk and read in the existing mbr. Either here or
  	 * when reading the block from disk, we do check for the version
  	 * and abort if a suitable block is not found.
  	 */
  	mbr_size = read_mbr(disk, &mbr, !B_flag);
  
  	/* save the existing MBR if we are asked to do so */
  	if (fpath)
  		write_mbr(fpath, O_CREAT | O_TRUNC, mbr, mbr_size, 0);
  
  	/*
  	 * If we are installing the boot loader, read it from disk and copy the
  	 * slice table over from the existing MBR.  If not, then point boot0
  	 * back at the MBR we just read in.  After this, boot0 is the data to
  	 * write back to disk if we are going to do a write.
  	 */
  	if (B_flag) {
  		boot0_size = read_mbr(bpath, &boot0, 1);
  		memcpy(boot0 + OFF_PTBL, mbr + OFF_PTBL,
  				sizeof(struct dos_partition) * NDOSPART);
  		if (b0_ver == 2) /* volume serial number support */
  			memcpy(boot0 + OFF_SERIAL, mbr + OFF_SERIAL, 4);
  	} else {
  		boot0 = mbr;
  		boot0_size = mbr_size;
  	}
  
  	/* set the drive */
  	if (d_arg != -1)
  		boot0[OFF_DRIVE] = d_arg;
  
  	/* set various flags */
  	if (m_arg != -1) {
  		boot0[OFF_FLAGS] &= 0xf0;
  		boot0[OFF_FLAGS] |= m_arg;
  	}
  	if (o_flag) {
  		boot0[OFF_FLAGS] &= o_and;
  		boot0[OFF_FLAGS] |= o_or;
  	}
  
  	/* set the default boot selection */
  	if (s_arg != -1)
  		boot0[OFF_OPT] = s_arg - 1;
  
  	/* set the timeout */
  	if (t_arg != -1)
  		mk2(boot0 + OFF_TICKS, t_arg);
  
  	/* set the bell char */
  	if (o_e != -1 && set_bell(boot0, o_e, 0) != -1)
  		up = 1;
  
  	if (vol_id[4]) {
  		if (b0_ver != 2)
  			errx(1, "incompatible boot block, cannot set volume ID");
  		boot0[OFF_SERIAL] = vol_id[0];
  		boot0[OFF_SERIAL + 1] = vol_id[1];
  		boot0[OFF_SERIAL + 2] = vol_id[2];
  		boot0[OFF_SERIAL + 3] = vol_id[3];
  		up = 1; /* force update */
  	}
  	/* write the MBR back to disk */
  	if (up)
  		write_mbr(disk, 0, boot0, boot0_size, vol_id[4] || b0_ver == 1);
  
  	/* display the MBR */
  	if (v_flag)
  		display_mbr(boot0);
  
  	/* clean up */
  	if (mbr != boot0)
  		free(boot0);
  	free(mbr);
  	free(disk);
  
      return 0;
  }
  
  /* get or set the 'bell' character to be used in case of errors.
   * Lookup for a certain code sequence, return -1 if not found.
   */
  static int
  set_bell(u_int8_t *mbr, int new_bell, int report)
  {
      /* lookup sequence: 0x100 means skip, 0x200 means done */
      static unsigned seq[] =
  		{ 0xb0, 0x100, 0xe8, 0x100, 0x100, 0x30, 0xe4, 0x200 };
      int ofs, i, c;
  	for (ofs = 0x60; ofs < 0x180; ofs++) { /* search range */
  		if (mbr[ofs] != seq[0]) /* search initial pattern */
  			continue;
  		for (i = 0;; i++) {
  			if (seq[i] == 0x200) { /* found */
  				c = mbr[ofs + 1];
  				if (!report)
  					mbr[ofs + 1] = c = new_bell;
  				else
  					printf("  bell=%c (0x%x)", (c >= ' ' && c < 0x7f) ? c : ' ',
  							c);
  				return c;
  			}
  			if (seq[i] != 0x100 && seq[i] != mbr[ofs + i])
  				break;
  		}
  	}
  	warn("bell not found");
  	return -1;
  }
  /*
   * Read in the MBR of the disk.  If it is boot0, then use the version to
   * read in all of it if necessary.  Use pointers to return a malloc'd
   * buffer containing the MBR and then return its size.
   */
  static int
  read_mbr(const char *disk, u_int8_t **mbr, int check_version)
  {
      u_int8_t buf[MBRSIZE];
      int mbr_size, fd;
      int ver;
      ssize_t n;
  
  	if ((fd = open(disk, O_RDONLY)) == -1)
  		err(1, "open %s", disk);
  	if ((n = read(fd, buf, MBRSIZE)) == -1)
  		err(1, "read %s", disk);
  	if (n != MBRSIZE)
  		errx(1, "%s: short read", disk);
  	if (cv2(buf + OFF_MAGIC) != 0xaa55)
  		errx(1, "%s: bad magic", disk);
  
  	if (!(ver = boot0bs(buf))) {
  		if (check_version)
  			errx(1, "%s: unknown or incompatible boot code", disk);
  	} else if (boot0version(buf) == 0x101) {
  		mbr_size = 1024;
  		if ((*mbr = malloc(mbr_size)) == NULL)
  			errx(1, "%s: unable to allocate read buffer", disk);
  		if (lseek(fd, 0, SEEK_SET) == -1
  				|| (n = read(fd, *mbr, mbr_size)) == -1)
  			err(1, "%s", disk);
  		if (n != mbr_size)
  			errx(1, "%s: short read", disk);
  		close(fd);
  		return (mbr_size);
  	}
  	if ((*mbr = malloc(sizeof(buf))) == NULL)
  		errx(1, "%s: unable to allocate MBR buffer", disk);
  	memcpy(*mbr, buf, sizeof(buf));
  	close(fd);
  
  	return sizeof(buf);
  }
  
  /*
   * Write out the mbr to the specified file.
   */
  static void
  write_mbr(const char *fname, int flags, u_int8_t *mbr, int mbr_size,
      int disable_dsn)
  {
  	struct gctl_req *grq;
  	const char *errmsg;
  	char *pname;
  	ssize_t n;
  	int fd;
  
  	fd = open(fname, O_WRONLY | flags, 0666);
  	if (fd != -1) {
  		n = write(fd, mbr, mbr_size);
  		close(fd);
  		if (n != mbr_size)
  			errx(1, "%s: short write", fname);
  		return;
  	}
      if (flags != 0)
      	err(1, "%s", fname);
      err(1, "write_mbr: %s", fname);
  }
  
  /*
   * Outputs an informative dump of the data in the MBR to stdout.
   */
  static void
  display_mbr(u_int8_t *mbr)
  {
      struct dos_partition *part;
      int i, version;
  
  	part = (struct dos_partition*) (mbr + DOSPARTOFF);
  	printf(fmt0);
  	for (i = 0; i < NDOSPART; i++)
  		if (part[i].dp_typ)
  			printf(fmt1, 1 + i, part[i].dp_flag,
  					part[i].dp_scyl + ((part[i].dp_ssect & 0xc0) << 2),
  					part[i].dp_shd, part[i].dp_ssect & 0x3f, part[i].dp_typ,
  					part[i].dp_ecyl + ((part[i].dp_esect & 0xc0) << 2),
  					part[i].dp_ehd, part[i].dp_esect & 0x3f, part[i].dp_start,
  					part[i].dp_size);
  	printf("\n");
  	version = boot0version(mbr);
  	printf("version=%d.%d  drive=0x%x  mask=0x%x  ticks=%u", version >> 8,
  			version & 0xff, mbr[OFF_DRIVE], mbr[OFF_FLAGS] & 0xf,
  			cv2(mbr + OFF_TICKS));
  	set_bell(mbr, 0, 1);
  	printf("\noptions=");
  	for (i = 0; i < nopt; i++) {
  		if (i)
  			printf(",");
  		if (!(mbr[OFF_FLAGS] & 1 << (7 - i)) ^ opttbl[i].def)
  			printf("no");
  		printf("%s", opttbl[i].tok);
  	}
  	printf("\n");
  	if (b0_ver == 2)
  		printf("volume serial ID %02x%02x-%02x%02x\n", mbr[OFF_SERIAL],
  				mbr[OFF_SERIAL + 1], mbr[OFF_SERIAL + 2], mbr[OFF_SERIAL + 3]);
  	printf("default_selection=F%d (", mbr[OFF_OPT] + 1);
  	if (mbr[OFF_OPT] < 4)
  		printf("Slice %d", mbr[OFF_OPT] + 1);
  	else if (mbr[OFF_OPT] == 4)
  		printf("Drive 1");
  	else
  		printf("PXE");
  	printf(")\n");
  }
  
  /*
   * Return the boot0 version with the minor revision in the low byte, and
   * the major revision in the next higher byte.
   */
  static int
  boot0version(const u_int8_t *bs)
  {
      /* Check for old version, and return 0x100 if found. */
      int v = boot0bs(bs);
      if (v != 0)
          return v << 8;
  
      /* We have a newer boot0, so extract the version number and return it. */
      return *(const int *)(bs + OFF_VERSION) & 0xffff;
  }
  
  /* descriptor of a pattern to match.
   * Start from the first entry trying to match the chunk of bytes,
   * if you hit an entry with len=0 terminate the search and report
   * off as the version. Otherwise skip to the next block after len=0
   * An entry with len=0, off=0 is the end marker.
    */
  struct byte_pattern {
      unsigned off;
      unsigned len;
      u_int8_t *key;
  };
  
  /*
   * Decide if we have valid boot0 boot code by looking for
   * characteristic byte sequences at fixed offsets.
   */
  static int
  boot0bs(const u_int8_t *bs)
  {
      /* the initial code sequence */
      static u_int8_t id0[] = {0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8,
  			     0x8e, 0xd0, 0xbc, 0x00, 0x7c };
      /* the drive id */
      static u_int8_t id1[] = {'D', 'r', 'i', 'v', 'e', ' '};
      static struct byte_pattern patterns[] = {
          {0x0,   sizeof(id0), id0},
          {0x1b2, sizeof(id1), id1},
          {1, 0, NULL},
          {0x0,   sizeof(id0), id0},	/* version with NT support */
          {0x1ae, sizeof(id1), id1},
          {2, 0, NULL},
          {0, 0, NULL},
      };
      struct byte_pattern *p = patterns;
  
  	for (; p->off || p->len; p++) {
  		if (p->len == 0)
  			break;
  		if (!memcmp(bs + p->off, p->key, p->len)) /* match */
  			continue;
  		while (p->len) /* skip to next block */
  			p++;
  	}
  	b0_ver = p->off; /* XXX ugly side effect */
  	return p->off;
  }
  
  /*
   * Adjust "and" and "or" masks for a -o option argument.
   */
  static void
  stropt(const char *arg, int *xa, int *xo)
  {
      const char *q;
      char *s, *s1;
      int inv, i, x;
  
  	if (!(s = strdup(arg)))
  		err(1, NULL);
  	for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) {
  		if ((inv = !strncmp(q, "no", 2)))
  			q += 2;
  		for (i = 0; i < nopt; i++)
  			if (!strcmp(q, opttbl[i].tok))
  				break;
  		if (i == nopt)
  			errx(1, "%s: Unknown -o option", q);
  		if (opttbl[i].def)
  			inv ^= 1;
  		x = 1 << (7 - i);
  		if (inv)
  			*xa &= ~x;
  		else
  			*xo |= x;
  	}
  	free(s);
  }
  
  /*
   * Convert and check an option argument.
   */
  static int
  argtoi(const char *arg, int lo, int hi, int opt)
  {
      char *s;
      long x;
  
  	errno = 0;
  	x = strtol(arg, &s, 0);
  	if (errno || !*arg || *s || x < lo || x > hi)
  		errx(1, "%s: Bad argument to -%c option", arg, opt);
  	return x;
  }
  
  /*
   * Display usage information.
   */
  static void
  usage(void)
  {
      fprintf(stderr, "%s\n%s\n",
      "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]",
      "                [-o options] [-s slice] [-t ticks] disk");
      exit(1);
  }
  