1 /* $OpenBSD: bootstrap.c,v 1.13 2019/06/28 13:32:48 deraadt 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
bootstrap(int devfd,char * dev,char * bootfile)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 == -1)
64 err(1, "open %s", bootfile);
65 if (fstat(fd, &sb) == -1)
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 fit - partitions must not overlap,
82 * or if they do, the partition type must be either FS_BOOT or
83 * FS_UNUSED. The 'c' partition will always overlap and is ignored.
84 */
85 if (verbose)
86 fprintf(stderr, "ensuring used partitions do not overlap "
87 "with bootstrap sectors 0-%zu\n", bootsec);
88 for (i = 0; i < dl.d_npartitions; i++) {
89 part = 'a' + i;
90 pp = &dl.d_partitions[i];
91 if (i == RAW_PART)
92 continue;
93 if (DL_GETPSIZE(pp) == 0)
94 continue;
95 if ((u_int64_t)bootsec <= DL_GETPOFFSET(pp))
96 continue;
97 switch (pp->p_fstype) {
98 case FS_BOOT:
99 break;
100 case FS_UNUSED:
101 warnx("bootstrap overlaps with unused partition %c",
102 part);
103 break;
104 default:
105 errx(1, "bootstrap overlaps with partition %c", part);
106 }
107 }
108
109 /*
110 * Make sure the bootstrap has left space for the disklabel.
111 * N.B.: LABELSECTOR *is* a DEV_BSIZE quantity!
112 */
113 lp = (struct disklabel *)(boot + (LABELSECTOR * DEV_BSIZE) +
114 LABELOFFSET);
115 for (i = 0, p = (char *)lp; i < (int)sizeof(*lp); i++)
116 if (p[i] != 0)
117 errx(1, "bootstrap has data in disklabel area");
118
119 /* Patch the disklabel into the bootstrap code. */
120 memcpy(lp, &dl, sizeof(dl));
121
122 /* Write the bootstrap out to the disk. */
123 if (verbose)
124 fprintf(stderr, "%s bootstrap to disk\n",
125 (nowrite ? "would write" : "writing"));
126 if (nowrite)
127 return;
128 if (pwrite(devfd, boot, bootsize, 0) != (ssize_t)bootsize)
129 err(1, "pwrite");
130 }
131