(2006-08-06) rescue-bootcd

extra/syslinux-3.09/sample/mdiskchk.c

@@ -0,0 +1,147 @@
+/* -*- c -*- ------------------------------------------------------------- *
+ *   
+ *   Copyright 2003-2004 H. Peter Anvin - All Rights Reserved
+ *
+ *   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., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+/* $Id: mdiskchk.c,v 1.7 2004/12/30 21:57:12 hpa Exp $ */
+
+/*
+ * mdiskchk.c
+ *
+ * DOS program to check for the existence of a memdisk.
+ *
+ * This program can be compiled for DOS with the OpenWatcom compiler
+ * (http://www.openwatcom.org/):
+ *
+ * wcl -3 -osx -mt mdiskchk.c
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <i86.h>		/* For MK_FP() */
+
+typedef unsigned long  uint32_t;
+typedef unsigned short uint16_t;
+typedef unsigned char  uint8_t;
+
+struct memdiskinfo {
+  uint16_t bytes;		/* Bytes from memdisk */
+  uint16_t version;		/* Memdisk version */
+  uint32_t base;		/* Base of disk in high memory */
+  uint32_t size;		/* Size of disk in sectors */
+  char far * cmdline;		/* Command line */
+  void far * oldint13;		/* Old INT 13h */
+  void far * oldint15;		/* Old INT 15h */
+  uint16_t olddosmem;
+  uint8_t  bootloaderid;
+
+  uint8_t _pad;
+
+  /* We add our own fields at the end */
+  int cylinders;
+  int heads;
+  int sectors;
+};
+
+struct memdiskinfo * query_memdisk(int drive)
+{
+  static struct memdiskinfo mm;
+  uint32_t _eax, _ebx, _ecx, _edx;
+  uint16_t _es, _di;
+  unsigned char _dl = drive;
+  uint16_t bytes;
+
+  __asm {
+    .386 ;
+    mov eax, 454d0800h ;
+    mov ecx, 444d0000h ;
+    mov edx, 53490000h ;
+    mov dl, _dl ;
+    mov ebx, 3f4b0000h ;
+    int 13h ;
+    mov _eax, eax ;
+    mov _ecx, ecx ;
+    mov _edx, edx ;
+    mov _ebx, ebx ;
+    mov _es, es ;
+    mov _di, di ;
+  }
+  
+  if ( _eax >> 16 != 0x4d21 ||
+       _ecx >> 16 != 0x4d45 ||
+       _edx >> 16 != 0x4944 ||
+       _ebx >> 16 != 0x4b53 )
+    return NULL;
+
+  memset(&mm, 0, sizeof mm);
+
+  bytes = *(uint16_t far *)MK_FP(_es, _di);
+
+  /* 27 is the most we know how to handle */
+  if ( bytes > 27 )
+    bytes = 27;
+
+  _fmemcpy((void far *)&mm, (void far *)MK_FP(_es,_di), bytes);
+
+  mm.cylinders = ((_ecx >> 8) & 0xff) + ((_ecx & 0xc0) << 2) + 1;
+  mm.heads     = ((_edx >> 8) & 0xff) + 1;
+  mm.sectors   = (_ecx & 0x3f);
+  
+  return &mm;
+}
+
+const char *bootloadername(uint8_t id)
+{
+  static const struct {
+    uint8_t id, mask;
+    const char *name;
+  } *lp, list[] =
+    {
+      { 0x10, 0xf0, "LILO" },
+      { 0x20, 0xf0, "LOADLIN" },
+      { 0x31, 0xff, "SYSLINUX" },
+      { 0x32, 0xff, "PXELINUX" },
+      { 0x33, 0xff, "ISOLINUX" },
+      { 0x34, 0xff, "EXTLINUX" },
+      { 0x30, 0xf0, "SYSLINUX family" },
+      { 0x40, 0xf0, "Etherboot" },
+      { 0x50, 0xf0, "ELILO" },
+      { 0x70, 0xf0, "GrUB" },
+      { 0x80, 0xf0, "U-Boot" },
+      { 0x00, 0x00, "unknown" }
+    };
+
+  for ( lp = list ; ; lp++ ) {
+    if ( ((id ^ lp->id) & lp->mask) == 0 )
+      return lp->name;
+  }
+}
+
+int main(int argc, char *argv[])
+{
+  int d;
+  int found = 0;
+  struct memdiskinfo *m;
+
+  for ( d = 0 ; d <= 0xff ; d++ ) {
+    if ( (m = query_memdisk(d)) != NULL ) {
+      printf("Drive %02X is MEMDISK %u.%02u:\n"
+	     "\tAddress = 0x%08lx, len = %lu sectors, chs = %u/%u/%u,\n"
+	     "\tloader = 0x%02x (%s),\n"
+	     "\tcmdline = %Fs\n",
+	     d, m->version >> 8, m->version & 0xff,
+	     m->base, m->size, m->cylinders, m->heads, m->sectors,
+	     m->bootloaderid, bootloadername(m->bootloaderid),
+	     m->cmdline);
+      found++;
+    }
+  }
+  
+  return found;
+}