1/*-
2 * Copyright 2015 Toomas Soome <tsoome@me.com>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27/*
28 * Chain loader to load BIOS boot block either from MBR or PBR.
29 *
30 * Note the boot block location 0000:7c000 conflicts with loader, so we need to
31 * read in to temporary space and relocate on exec, when btx is stopped.
32 */
33
34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD$");
36
37#include <stand.h>
38#include <sys/param.h>
39#include <sys/linker.h>
40#include <sys/diskmbr.h>
41
42#include "bootstrap.h"
43#include "libi386/libi386.h"
44#include "btxv86.h"
45
46#ifdef LOADER_VERIEXEC_VECTX
47#define VECTX_HANDLE(x) vctx
48#else
49#define VECTX_HANDLE(x) x
50#endif
51
52/*
53 * The MBR/VBR is located in first sector of disk/partition.
54 * Read 512B to temporary location and set up relocation. Then
55 * exec relocator.
56 */
57#define	SECTOR_SIZE	(512)
58
59COMMAND_SET(chain, "chain", "chain load boot block from device", command_chain);
60
61static int
62command_chain(int argc, char *argv[])
63{
64	int fd, len, size = SECTOR_SIZE;
65	struct stat st;
66	vm_offset_t mem = 0x100000;
67	struct i386_devdesc *rootdev;
68#ifdef LOADER_VERIEXEC_VECTX
69	struct vectx *vctx;
70	int verror;
71#endif
72
73	if (argc == 1) {
74		command_errmsg = "no device or file name specified";
75		return (CMD_ERROR);
76	}
77	if (argc != 2) {
78		command_errmsg = "invalid trailing arguments";
79		return (CMD_ERROR);
80	}
81
82	fd = open(argv[1], O_RDONLY);
83	if (fd == -1) {
84		command_errmsg = "open failed";
85		return (CMD_ERROR);
86	}
87
88#ifdef LOADER_VERIEXEC_VECTX
89	vctx = vectx_open(fd, argv[1], 0L, NULL, &verror, __func__);
90	if (verror) {
91		sprintf(command_errbuf, "can't verify: %s", argv[1]);
92		close(fd);
93		free(vctx);
94		return (CMD_ERROR);
95	}
96#else
97#ifdef LOADER_VERIEXEC
98	if (verify_file(fd, argv[1], 0, VE_MUST, __func__) < 0) {
99		sprintf(command_errbuf, "can't verify: %s", argv[1]);
100		close(fd);
101		return (CMD_ERROR);
102	}
103#endif
104#endif
105	len = strlen(argv[1]);
106	if (argv[1][len-1] != ':') {
107		if (fstat(fd, &st) == -1) {
108			command_errmsg = "stat failed";
109			close(fd);
110			return (CMD_ERROR);
111		}
112		size = st.st_size;
113	} else if (strncmp(argv[1], "disk", 4) != 0) {
114		command_errmsg = "can only use disk device";
115		close(fd);
116		return (CMD_ERROR);
117	}
118
119	i386_getdev((void **)(&rootdev), argv[1], NULL);
120	if (rootdev == NULL) {
121		command_errmsg = "can't determine root device";
122		close(fd);
123		return (CMD_ERROR);
124	}
125
126	if (archsw.arch_readin(VECTX_HANDLE(fd), mem, size) != size) {
127		command_errmsg = "failed to read disk";
128		close(fd);
129		return (CMD_ERROR);
130	}
131	close(fd);
132#ifdef LOADER_VERIEXEC_VECTX
133	verror = vectx_close(vctx, VE_MUST, __func__);
134	if (verror) {
135		free(vctx);
136		return (CMD_ERROR);
137	}
138#endif
139	if (argv[1][len-1] == ':' &&
140	    *((uint16_t *)PTOV(mem + DOSMAGICOFFSET)) != DOSMAGIC) {
141		command_errmsg = "wrong magic";
142		return (CMD_ERROR);
143	}
144
145	relocater_data[0].src = mem;
146	relocater_data[0].dest = 0x7C00;
147	relocater_data[0].size = size;
148
149	relocator_edx = bd_unit2bios(rootdev);
150	relocator_esi = relocater_size;
151	relocator_ds = 0;
152	relocator_es = 0;
153	relocator_fs = 0;
154	relocator_gs = 0;
155	relocator_ss = 0;
156	relocator_cs = 0;
157	relocator_sp = 0x7C00;
158	relocator_ip = 0x7C00;
159	relocator_a20_enabled = 0;
160
161	i386_copyin(relocater, 0x600, relocater_size);
162
163	dev_cleanup();
164
165	__exec((void *)0x600);
166
167	panic("exec returned");
168	return (CMD_ERROR);		/* not reached */
169}
170