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authorH. Peter Anvin <hpa@zytor.com>2008-06-12 17:11:42 -0700
committerH. Peter Anvin <hpa@zytor.com>2008-06-12 17:11:42 -0700
commitba78fe75b084313d7eaf77e130a4d1af7e79258f (patch)
tree2b577d52950085830ff12f509007c62d73c064c7
parent54665c9740f1d95f9ff88452cb2aa1baeaf03a7c (diff)
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chain: use shuffle API; support loading a boot file
Use the shuffle API, and support loading a boot file instead of the standard boot sector. This should be able to load NTLDR.
-rw-r--r--com32/modules/chain.c127
1 files changed, 100 insertions, 27 deletions
diff --git a/com32/modules/chain.c b/com32/modules/chain.c
index ec92cd0c..3a614e1b 100644
--- a/com32/modules/chain.c
+++ b/com32/modules/chain.c
@@ -15,9 +15,9 @@
*
* Chainload a hard disk (currently rather braindead.)
*
- * Usage: chain hd<disk#> [<partition>]
- * chain fd<disk#>
- * chain mbr:<id> [<partition>]
+ * Usage: chain hd<disk#> [<partition>] [-ntldr] [-file <loader>]
+ * chain fd<disk#> [-ntldr] [-file <loader>]
+ * chain mbr:<id> [<partition>] [-ntldr] [-file <loader>]
*
* ... e.g. "chain hd0 1" will boot the first partition on the first hard
* disk.
@@ -26,6 +26,13 @@
* specific MBR serial number (bytes 440-443) is found.
*
* Partitions 1-4 are primary, 5+ logical, 0 = boot MBR (default.)
+ *
+ * -file <loader> loads the file <loader> **from the SYSLINUX filesystem**
+ * instead of loading the boot sector.
+ *
+ * -ntldr jumps to 07C0:0000 instead of 0000:7C00, not sure if this is
+ * really necessary.
+ *
*/
#include <com32.h>
@@ -34,6 +41,9 @@
#include <ctype.h>
#include <string.h>
#include <console.h>
+#include <stdbool.h>
+#include <syslinux/loadfile.h>
+#include <syslinux/bootrm.h>
#define SECTOR 512 /* bytes/sector */
@@ -45,7 +55,7 @@ static inline void error(const char *msg)
/*
* Call int 13h, but with retry on failure. Especially floppies need this.
*/
-int int13_retry(const com32sys_t *inreg, com32sys_t *outreg)
+static int int13_retry(const com32sys_t *inreg, com32sys_t *outreg)
{
int retry = 6; /* Number of retries */
com32sys_t tmpregs;
@@ -72,7 +82,7 @@ struct diskinfo {
int sect;
} disk_info;
-int get_disk_params(int disk)
+static int get_disk_params(int disk)
{
static com32sys_t getparm, parm, getebios, ebios;
@@ -126,7 +136,7 @@ struct ebios_dapa {
uint64_t lba;
} *dapa;
-int read_sector(void *buf, unsigned int lba)
+static int read_sector(void *buf, unsigned int lba)
{
com32sys_t inreg;
@@ -177,7 +187,7 @@ int read_sector(void *buf, unsigned int lba)
/* Search for a specific drive, based on the MBR signature; bytes
440-443. */
-int find_disk(uint32_t mbr_sig, void *buf)
+static int find_disk(uint32_t mbr_sig, void *buf)
{
int drive;
@@ -220,7 +230,7 @@ struct part_entry {
int nextpart; /* Number of the next logical partition */
-struct part_entry *
+static struct part_entry *
find_logical_partition(int whichpart, char *table, struct part_entry *self,
struct part_entry *root)
{
@@ -293,22 +303,87 @@ find_logical_partition(int whichpart, char *table, struct part_entry *self,
return NULL;
}
+static void do_boot(uint16_t keeppxe, void *boot_sector,
+ size_t boot_size, struct syslinux_rm_regs *regs)
+{
+ struct syslinux_memmap *mmap;
+ struct syslinux_movelist *mlist = NULL;
+
+ mmap = syslinux_memory_map();
+
+ if (!mmap) {
+ error("Cannot read system memory map");
+ return;
+ }
+
+ if (syslinux_memmap_type(mmap, 0x7c00, boot_size) != SMT_FREE) {
+ error("Loader file too large");
+ return;
+ }
+
+ if (syslinux_add_movelist(&mlist, 0x7c00, (addr_t)boot_sector, boot_size)) {
+ error("Out of memory");
+ return;
+ }
+
+ fputs("Booting...\n", stdout);
+
+ syslinux_shuffle_boot_rm(mlist, mmap, keeppxe, regs);
+
+ /* If we get here, badness happened */
+ error("Chainboot failed!\n");
+}
int main(int argc, char *argv[])
{
- char *mbr, *boot_sector = NULL;
+ char *mbr;
+ void *boot_sector = NULL;
struct part_entry *partinfo;
+ struct syslinux_rm_regs regs;
char *drivename, *partition;
int hd, drive, whichpart;
- static com32sys_t inreg; /* In bss, so zeroed automatically */
+ int i;
+ uint16_t keeppxe = 0;
+ bool ntldr = false;
+ const char *load_file;
+ size_t boot_size = SECTOR;
openconsole(&dev_null_r, &dev_stdcon_w);
- if ( argc < 2 ) {
- error("Usage: chain.c32 (hd#|fd#|mbr:#) [partition]\n");
+ drivename = NULL;
+ partition = NULL;
+ load_file = NULL;
+
+ /* Prepare the register set */
+ memset(&regs, 0, sizeof regs);
+
+ for (i = 1; i < argc; i++) {
+ if (!strcmp(argv[i], "-file") && argv[i+1]) {
+ load_file = argv[++i];
+ } else if (!strcmp(argv[i], "-ntldr")) {
+ ntldr = true;
+ } else if (!strcmp(argv[i], "keeppxe")) {
+ keeppxe = 3;
+ } else {
+ if (!drivename)
+ drivename = argv[i];
+ else if (!partition)
+ partition = argv[i];
+ }
+ }
+
+ if ( !drivename ) {
+ error("Usage: chain.c32 (hd#|fd#|mbr:#) [partition] [-ntldr] "
+ "[-file loader]\n");
goto bail;
}
+ if (ntldr) {
+ regs.es = regs.cs = regs.ss = regs.ds = regs.fs = regs.gs = 0x07c0;
+ } else {
+ regs.ip = regs.esp.l = 0x7c00;
+ }
+
/* Divvy up the bounce buffer. To keep things sector-
aligned, give the EBIOS DAPA the first sector, then
the MBR next, and the rest is used for the partition-
@@ -335,6 +410,8 @@ int main(int argc, char *argv[])
drive = (hd ? 0x80 : 0) | strtoul(drivename, NULL, 0);
}
+ regs.edx.b[0] = drive;
+
whichpart = 0; /* Default */
if ( partition )
@@ -380,32 +457,28 @@ int main(int argc, char *argv[])
}
/* Do the actual chainloading */
- if ( partinfo ) {
+ if (load_file) {
+ if ( loadfile(load_file, &boot_sector, &boot_size) ) {
+ error("Failed to load the boot file\n");
+ goto bail;
+ }
+ } else if (partinfo) {
/* Actually read the boot sector */
/* Pick the first buffer that isn't already in use */
- boot_sector = (char *)(((unsigned long)partinfo + 511) & ~511);
+ boot_sector = (void *)(((uintptr_t)partinfo + 511) & ~511);
if ( read_sector(boot_sector, partinfo->start_lba) ) {
error("Cannot read boot sector\n");
goto bail;
}
+ }
+ if (partinfo) {
/* 0x7BE is the canonical place for the first partition entry. */
- inreg.esi.w[0] = 0x7be;
+ regs.esi.w[0] = 0x7be;
memcpy((char *)0x7be, partinfo, sizeof(*partinfo));
}
- fputs("Booting...\n", stdout);
-
- inreg.eax.w[0] = 0x000d; /* Clean up and chain boot */
- inreg.edx.w[0] = 0; /* Should be 3 for "keeppxe" */
- inreg.edi.l = (uint32_t)boot_sector;
- inreg.ecx.l = SECTOR; /* One sector */
- inreg.ebx.b[0] = drive; /* DL = drive no */
-
- __intcall(0x22, &inreg, NULL);
-
- /* If we get here, badness happened */
- error("Chainboot failed!\n");
+ do_boot(keeppxe, boot_sector, boot_size, &regs);
bail:
return 255;