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-rw-r--r--com32/elflink/ldlinux/chainboot.c156
1 files changed, 156 insertions, 0 deletions
diff --git a/com32/elflink/ldlinux/chainboot.c b/com32/elflink/ldlinux/chainboot.c
new file mode 100644
index 00000000..27d4618c
--- /dev/null
+++ b/com32/elflink/ldlinux/chainboot.c
@@ -0,0 +1,156 @@
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2012 Intel Corporation, author: H. Peter Anvin
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston MA 02110-1301, USA; either version 2 of the License, or
+ * (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * chainbooting - replace the current bootloader completely. This
+ * is BIOS-specific.
+ */
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <dprintf.h>
+
+#include <com32.h>
+#include <sys/exec.h>
+#include <sys/io.h>
+#include "core.h"
+#include "menu.h"
+#include "fs.h"
+#include "config.h"
+#include "localboot.h"
+#include "bios.h"
+
+#include <syslinux/boot.h>
+#include <syslinux/bootrm.h>
+#include <syslinux/movebits.h>
+#include <syslinux/config.h>
+
+void chainboot_file(const char *file, uint32_t type)
+{
+ uint8_t keeppxe = 0;
+ const union syslinux_derivative_info *sdi;
+ struct syslinux_rm_regs regs;
+ struct syslinux_movelist *fraglist = NULL;
+ struct syslinux_memmap *mmap = NULL;
+ struct com32_filedata fd;
+ com32sys_t reg;
+ char *stack;
+ void *buf;
+ int rv, max, size;
+
+ max = 0xA0000; /* Maximum load */
+ buf = malloc(max);
+ if (!buf)
+ goto bail;
+
+ rv = open_file(file, O_RDONLY, &fd);
+ if (rv == -1)
+ goto bail;
+
+ reg.eax.l = max;
+ reg.ebx.l = 0;
+ reg.edx.w[0] = 0;
+ reg.edi.l = (uint32_t)buf;
+ reg.ebp.l = -1; /* XXX: limit? */
+ reg.esi.w[0] = rv;
+
+ pm_load_high(&reg);
+
+ size = reg.edi.l - (unsigned long)buf;
+ if (size > 0xA0000 - 0x7C00) {
+ printf("Too large for a boostrap (need LINUX instead of KERNEL?)\n");
+ goto bail;
+ }
+
+ mmap = syslinux_memory_map();
+ if (!mmap)
+ goto bail;
+
+ sdi = syslinux_derivative_info();
+
+ memset(&regs, 0, sizeof(regs));
+ regs.ip = 0x7c00;
+
+ if (sdi->c.filesystem == SYSLINUX_FS_SYSLINUX ||
+ sdi->c.filesystem == SYSLINUX_FS_EXTLINUX) {
+ if (syslinux_add_movelist(&fraglist, 0x800 - 18,
+ (addr_t)sdi->r.esbx, 16))
+ goto bail;
+
+ /* DS:SI points to partition info */
+ regs.esi.l = 0x800 - 18;
+ }
+
+ /*
+ * For a BSS boot sector we have to transfer the
+ * superblock.
+ */
+ if (sdi->c.filesystem == SYSLINUX_FS_SYSLINUX &&
+ type == IMAGE_TYPE_BSS && this_fs->fs_ops->copy_super(buf))
+ goto bail;
+
+ if (sdi->c.filesystem == SYSLINUX_FS_PXELINUX) {
+ keeppxe = 0x03; /* Chainloading + keep PXE */
+ stack = (char *)sdi->r.fssi;
+
+ /*
+ * Set up the registers with their initial values
+ */
+
+ regs.eax.l = *(uint32_t *)&stack[36];
+ regs.ecx.l = *(uint32_t *)&stack[32];
+ regs.edx.l = *(uint32_t *)&stack[28];
+ regs.ebx.l = *(uint32_t *)&stack[24];
+ regs.esp.l = sdi->rr.r.esi.w[0] + 44;
+ regs.ebp.l = *(uint32_t *)&stack[16];
+ regs.esi.l = *(uint32_t *)&stack[12];
+ regs.edi.l = *(uint32_t *)&stack[8];
+ regs.es = *(uint16_t *)&stack[4];
+ regs.ss = sdi->rr.r.fs;
+ regs.ds = *(uint16_t *)&stack[6];
+ regs.fs = *(uint16_t *)&stack[2];
+ regs.gs = *(uint16_t *)&stack[0];
+ } else {
+ const uint16_t *esdi = (const uint16_t *)sdi->disk.esdi_ptr;
+
+ regs.esp.l = (uint16_t)(unsigned long)StackBuf + 44;
+
+ /*
+ * DON'T DO THIS FOR PXELINUX...
+ * For PXE, ES:BX -> PXENV+, and this would
+ * corrupt that use.
+ *
+ * Restore ES:DI -> $PnP (if we were ourselves
+ * called that way...)
+ */
+ regs.edi.w[0] = esdi[0]; /* New DI */
+ regs.es = esdi[2]; /* New ES */
+
+ regs.edx.l = sdi->rr.r.edx.b[0]; /* Drive number -> DL */
+ }
+
+ if (syslinux_add_movelist(&fraglist, 0x7c00, (addr_t)buf, size))
+ goto bail;
+
+ syslinux_shuffle_boot_rm(fraglist, mmap, keeppxe, &regs);
+
+bail:
+ if (fraglist)
+ syslinux_free_movelist(fraglist);
+ if (mmap)
+ syslinux_free_memmap(mmap);
+ if (buf)
+ free(buf);
+ return;
+}