1 /* $OpenBSD: bootstrap.c,v 1.11 2018/11/25 17:34:37 krw Exp $ */ 2 3 /* 4 * Copyright (c) 2013 Joel Sing <jsing@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/param.h> /* DEV_BSIZE */ 20 #include <sys/disklabel.h> 21 #include <sys/dkio.h> 22 #include <sys/ioctl.h> 23 #include <sys/stat.h> 24 25 #include <err.h> 26 #include <fcntl.h> 27 #include <stdio.h> 28 #include <stdlib.h> 29 #include <string.h> 30 #include <unistd.h> 31 32 #include "installboot.h" 33 34 void 35 bootstrap(int devfd, char *dev, char *bootfile) 36 { 37 struct disklabel dl; 38 struct disklabel *lp; 39 struct partition *pp; 40 char *boot, *p, part; 41 size_t bootsize; 42 size_t bootsec; 43 struct stat sb; 44 int fd, i; 45 46 /* 47 * Install bootstrap code onto the given disk, preserving the 48 * existing disklabel. 49 */ 50 51 /* Read disklabel from disk. */ 52 if (ioctl(devfd, DIOCGDINFO, &dl) == -1) 53 err(1, "disklabel"); 54 if (dl.d_secsize == 0) { 55 warnx("disklabel has sector size of 0, assuming %d", DEV_BSIZE); 56 dl.d_secsize = DEV_BSIZE; 57 } 58 59 /* Read bootstrap file. */ 60 if (verbose) 61 fprintf(stderr, "reading bootstrap from %s\n", bootfile); 62 fd = open(bootfile, O_RDONLY); 63 if (fd < 0) 64 err(1, "open %s", bootfile); 65 if (fstat(fd, &sb) != 0) 66 err(1, "fstat %s", bootfile); 67 bootsec = howmany((ssize_t)sb.st_size, dl.d_secsize); 68 bootsize = bootsec * dl.d_secsize; 69 if (verbose) 70 fprintf(stderr, "bootstrap is %zu bytes " 71 "(%zu sectors @ %u bytes = %zu bytes)\n", 72 (ssize_t)sb.st_size, bootsec, dl.d_secsize, bootsize); 73 boot = calloc(1, bootsize); 74 if (boot == NULL) 75 err(1, "calloc"); 76 if (read(fd, boot, bootsize) != (ssize_t)sb.st_size) 77 err(1, "read"); 78 close(fd); 79 80 /* 81 * Check that the bootstrap will not intrude into the OpenBSD area 82 * of the disk. 83 */ 84 if (bootsec > DL_GETBSTART(&dl)) 85 errx(1, "bootstrap (sectors 0 - %zu) overlaps OpenBSD " 86 " area (sectors %zu - %zu)", bootsec, 87 DL_GETBSTART(&dl), DL_GETBEND(&dl)); 88 else if (verbose) 89 fprintf(stderr, "bootstrap (sectors 0 - %zu) does not overlap " 90 "OpenBSD area.\n", bootsec); 91 92 /* 93 * Make sure the bootstrap has left space for the disklabel. 94 * N.B.: LABELSECTOR *is* a DEV_BSIZE quantity! 95 */ 96 lp = (struct disklabel *)(boot + (LABELSECTOR * DEV_BSIZE) + 97 LABELOFFSET); 98 for (i = 0, p = (char *)lp; i < (int)sizeof(*lp); i++) 99 if (p[i] != 0) 100 errx(1, "bootstrap has data in disklabel area"); 101 102 /* Patch the disklabel into the bootstrap code. */ 103 memcpy(lp, &dl, sizeof(dl)); 104 105 /* Write the bootstrap out to the disk. */ 106 if (verbose) 107 fprintf(stderr, "%s bootstrap to disk\n", 108 (nowrite ? "would write" : "writing")); 109 if (nowrite) 110 return; 111 if (pwrite(devfd, boot, bootsize, 0) != (ssize_t)bootsize) 112 err(1, "pwrite"); 113 } 114