dbgcom.dif

很好用的内存泄漏检测工具。要配合linux的gcc使用,安装后将你的编译器gcc命令换成yamd-gcc就行了

--- src/debug/common/dbgcom.c.orig	Mon Mar 22 20:25:17 1999
+++ src/debug/common/dbgcom.c	Tue Mar 23 14:18:17 1999
@@ -27,6 +27,7 @@
 #define DOS_DESCRIPTOR_COUNT	128
 
 long mem_handles[MEM_HANDLE_COUNT];
+unsigned long block_base_addresses[MEM_HANDLE_COUNT];
 unsigned short descriptors[DESCRIPTOR_COUNT];
 unsigned short dos_descriptors[DOS_DESCRIPTOR_COUNT];
 NPX npx;
@@ -211,8 +212,15 @@
 	.text								\n\
 	.align  2,0x90							\n\
 _change_handle:								\n\
+	pushl	%ebx							\n\
 	pushl	%ecx							\n\
+	pushw	%bx							\n\
+	pushw	%cx							\n\
+	popl	%ebx /* get address of block */				\n\
 	xorl	%ecx,%ecx						\n\
+	orl	%edx, %edx						\n\
+	jnz	CL1							\n\
+	xorl	%ebx, %ebx /* zero address if freeing */		\n\
 CL1:									\n\
 	.byte	0x2e 							\n\
 	cmpl	%eax,_mem_handles(,%ecx,4)				\n\
@@ -222,14 +230,17 @@
 	movw	_my_ds,%ax						\n\
 	movw	%ax,%ds							\n\
 	movl	%edx,_mem_handles(,%ecx,4)				\n\
+	movl	%ebx,_block_base_addresses(,%ecx,4)			\n\
 	pop	%ds							\n\
 	popl	%ecx							\n\
+	popl	%ebx							\n\
 	ret								\n\
 CL2:									\n\
 	incl	%ecx							\n\
 	cmpl	$256,%ecx	/* MEM_HANDLE_COUNT */			\n\
 	jl	CL1							\n\
 	popl	%ecx							\n\
+	popl	%ebx							\n\
 	ret								\n"
 );
 
@@ -600,28 +611,70 @@
   _clear_break_DPMI();
 }
 
-static int invalid_addr(unsigned a, unsigned len)
+static void setup_handle_and_address(unsigned a, __dpmi_meminfo *m)
+{
+  int i, best;
+  unsigned bestdiff;
+  unsigned long base;
+  unsigned linear;
+  __dpmi_get_segment_base_address(__djgpp_app_DS, &base);
+  linear = a + base;
+  best = -1;
+  bestdiff = 0xffffffff;
+  for (i = 0; i < MEM_HANDLE_COUNT; i++)
+    {
+      if (block_base_addresses[i]
+	  && linear > block_base_addresses[i]
+	  && (block_base_addresses[i] - linear) < bestdiff)
+	{	
+	  best = i;
+	  bestdiff = block_base_addresses[i] - linear;
+	}
+    }
+  m->handle = mem_handles[best];
+  m->address = linear - block_base_addresses[best];
+}
+
+static int invalid_addr(unsigned a, unsigned len, int wr)
 {
   /* Here we assume expand up writable code.  We could check the rights to
      be sure, but that's a waste unless *_child routines fixed to know about
      different selectors. */
 
   unsigned limit;
+  if (a <= 4096)
+    return 1; /* Null page */
   limit = __dpmi_get_segment_limit(__djgpp_app_DS);
-  if(4096 <= a             /* First page is used for NULL pointer detection. */
-  && a <= limit            /* To guard against limit < len. */
-  && a - 1 <= limit - len  /* To guard against limit <= a + len - 1. */
-     )
-    return 0;
-/*  printf("Invalid access to child, address %#x length %#x  limit: %#x\n", a, len, limit);
-  if (can_longjmp)
-    longjmp(debugger_jmpbuf, 1); */
-  return 1;
+  if (a > limit || (a - 1) > (limit - len))
+      return 1; /* Beyond limit */
+  {
+    unsigned short *attr;
+    __dpmi_meminfo m;
+    unsigned long startpg;
+    unsigned long npgs;
+
+    startpg = (unsigned long)a & ~4095;
+    npgs = (len + 4095) / 4096;
+    attr = alloca(npgs * sizeof(unsigned short));
+    setup_handle_and_address(startpg, &m);
+    m.size = npgs;
+    if (__dpmi_get_page_attributes(&m, attr) == 0)
+      {
+	int i;
+	for (i = 0; i < npgs; i++)
+	  {
+	    if (((attr[i] & 7) == 0) /* uncommitted */
+		|| (wr && !(attr[i] & 8))) /* read-only */
+		return 1;
+	  }
+      }
+  }
+  return 0;
 }
 
 int read_child(unsigned child_addr, void *buf, unsigned len)
 {
-  if (invalid_addr(child_addr, len))
+  if (invalid_addr(child_addr, len, 0))
     return 1;
   movedata(__djgpp_app_DS, child_addr, my_ds, (int)buf, len);
   return 0;
@@ -629,7 +682,7 @@
 
 int write_child(unsigned child_addr, void *buf, unsigned len)
 {
-  if (invalid_addr(child_addr, len))
+  if (invalid_addr(child_addr, len, 1))
     return 1;
   movedata(my_ds, (int)buf, __djgpp_app_DS, child_addr, len);
   return 0;
@@ -671,6 +724,13 @@
   movedata(a_tss.tss_fs,0,my_ds,(unsigned)&si,sizeof(si));
   memset(mem_handles,0,sizeof(mem_handles));
   mem_handles[0] = si.memory_handle;
+  /* Kludge: The base address of the first handle is also the base
+     address of the DS segment. */
+  {
+    unsigned long b;
+    __dpmi_get_segment_base_address(__djgpp_app_DS, &b);
+    block_base_addresses[0] = b;
+  }
   memset(descriptors,0,sizeof(descriptors));
   descriptors[0] = si.cs_selector;
   descriptors[1] = si.ds_selector;