270d043936
The current chain command does accept only device, allow also a file to be used, such as /boot/pmbr or /boot/mbr (or stored third party MBR/VBR block). Also fix file descriptor leak.
137 lines
3.7 KiB
C
137 lines
3.7 KiB
C
/*-
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* Copyright 2015 Toomas Soome <tsoome@me.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Chain loader to load BIOS boot block either from MBR or PBR.
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*
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* Note the boot block location 0000:7c000 conflicts with loader, so we need to
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* read in to temporary space and relocate on exec, when btx is stopped.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <stand.h>
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#include <sys/param.h>
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#include <sys/linker.h>
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#include <sys/diskmbr.h>
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#include "bootstrap.h"
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#include "libi386/libi386.h"
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#include "btxv86.h"
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/*
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* The MBR/VBR is located in first sector of disk/partition.
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* Read 512B to temporary location and set up relocation. Then
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* exec relocator.
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*/
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#define SECTOR_SIZE (512)
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COMMAND_SET(chain, "chain", "chain load boot block from device", command_chain);
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static int
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command_chain(int argc, char *argv[])
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{
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int fd, len, size = SECTOR_SIZE;
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struct stat st;
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vm_offset_t mem = 0x100000;
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struct i386_devdesc *rootdev;
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if (argc == 1) {
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command_errmsg = "no device or file name specified";
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return (CMD_ERROR);
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}
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if (argc != 2) {
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command_errmsg = "invalid trailing arguments";
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return (CMD_ERROR);
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}
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fd = open(argv[1], O_RDONLY);
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if (fd == -1) {
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command_errmsg = "open failed";
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return (CMD_ERROR);
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}
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len = strlen(argv[1]);
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if (argv[1][len-1] != ':') {
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if (fstat(fd, &st) == -1) {
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command_errmsg = "stat failed";
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close(fd);
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return (CMD_ERROR);
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}
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size = st.st_size;
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} else if (strncmp(argv[1], "disk", 4) != 0) {
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command_errmsg = "can only use disk device";
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close(fd);
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return (CMD_ERROR);
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}
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i386_getdev((void **)(&rootdev), argv[1], NULL);
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if (rootdev == NULL) {
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command_errmsg = "can't determine root device";
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close(fd);
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return (CMD_ERROR);
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}
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if (archsw.arch_readin(fd, mem, size) != size) {
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command_errmsg = "failed to read disk";
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close(fd);
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return (CMD_ERROR);
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}
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close(fd);
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if (argv[1][len-1] == ':' &&
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*((uint16_t *)PTOV(mem + DOSMAGICOFFSET)) != DOSMAGIC) {
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command_errmsg = "wrong magic";
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return (CMD_ERROR);
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}
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relocater_data[0].src = mem;
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relocater_data[0].dest = 0x7C00;
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relocater_data[0].size = size;
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relocator_edx = bd_unit2bios(rootdev->dd.d_unit);
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relocator_esi = relocater_size;
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relocator_ds = 0;
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relocator_es = 0;
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relocator_fs = 0;
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relocator_gs = 0;
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relocator_ss = 0;
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relocator_cs = 0;
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relocator_sp = 0x7C00;
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relocator_ip = 0x7C00;
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relocator_a20_enabled = 0;
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i386_copyin(relocater, 0x600, relocater_size);
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dev_cleanup();
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__exec((void *)0x600);
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panic("exec returned");
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return (CMD_ERROR); /* not reached */
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}
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