From: Nicholas Clark <nick@ccl4.org>
Date: Fri, 23 Dec 2005 16:55:35 +0000 (+0000)
Subject: If PERL_TRACK_MEMPOOL and PERL_POISON are in use, then scribble all
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=cd1541b29232033fba1800a2ccd9ae38b4e1b8c3;p=p5sagit%2Fp5-mst-13.2.git

If PERL_TRACK_MEMPOOL and PERL_POISON are in use, then scribble all
over memory to invalidate it just before free()ing it.

p4raw-id: //depot/perl@26476
---

diff --git a/perl.h b/perl.h
index b314184..f478c22 100644
--- a/perl.h
+++ b/perl.h
@@ -138,8 +138,6 @@
 
 #define pVAR    register struct perl_vars* my_vars PERL_UNUSED_DECL
 
-typedef struct interpreter PerlInterpreter;
-
 #ifdef PERL_GLOBAL_STRUCT
 #  define dVAR		pVAR    = (struct perl_vars*)PERL_GET_VARS()
 #else
@@ -151,14 +149,6 @@ typedef struct interpreter PerlInterpreter;
 #    define MULTIPLICITY
 #  endif
 #  define tTHX	PerlInterpreter*
-
-struct perl_memory_debug_header {
-  tTHX	interpreter;
-};
-
-#  define sTHX	(sizeof(struct perl_memory_debug_header) + \
-	(MEM_ALIGNBYTES - sizeof(struct perl_memory_debug_header) \
-	 %MEM_ALIGNBYTES) % MEM_ALIGNBYTES)
 #  define pTHX	register tTHX my_perl PERL_UNUSED_DECL
 #  define aTHX	my_perl
 #  ifdef PERL_GLOBAL_STRUCT
@@ -2164,6 +2154,8 @@ typedef struct padop PADOP;
 typedef struct pvop PVOP;
 typedef struct loop LOOP;
 
+typedef struct interpreter PerlInterpreter;
+
 /* Amdahl's <ksync.h> has struct sv */
 /* SGI's <sys/sema.h> has struct sv */
 #if defined(UTS) || defined(__sgi)
@@ -3734,6 +3726,24 @@ typedef Sighandler_t Sigsave_t;
 #  define MALLOC_TERM
 #endif
 
+#if defined(PERL_IMPLICIT_CONTEXT)
+struct perl_memory_debug_header {
+  tTHX	interpreter;
+#  ifdef PERL_POISON
+  MEM_SIZE size;
+  U8 in_use;
+#  endif
+
+#define PERL_POISON_INUSE 29
+#define PERL_POISON_FREE 159
+};
+
+#  define sTHX	(sizeof(struct perl_memory_debug_header) + \
+	(MEM_ALIGNBYTES - sizeof(struct perl_memory_debug_header) \
+	 %MEM_ALIGNBYTES) % MEM_ALIGNBYTES)
+
+#endif
+
 
 typedef int (CPERLscope(*runops_proc_t)) (pTHX);
 typedef void (CPERLscope(*share_proc_t)) (pTHX_ SV *sv);
diff --git a/util.c b/util.c
index 34bf4bb..c9e4446 100644
--- a/util.c
+++ b/util.c
@@ -94,6 +94,10 @@ Perl_safesysmalloc(MEM_SIZE size)
     if (ptr != Nullch) {
 #ifdef PERL_TRACK_MEMPOOL
         ((struct perl_memory_debug_header *)ptr)->interpreter = aTHX;
+#  ifdef PERL_POISON
+        ((struct perl_memory_debug_header *)ptr)->size = size;
+        ((struct perl_memory_debug_header *)ptr)->in_use = PERL_POISON_INUSE;
+#  endif
         ptr = (Malloc_t)((char*)ptr+sTHX);
 #endif
 	return ptr;
@@ -138,6 +142,10 @@ Perl_safesysrealloc(Malloc_t where,MEM_SIZE size)
 	/* int *nowhere = NULL; *nowhere = 0; */
         Perl_croak_nocontext("panic: realloc from wrong pool");
     }
+#  ifdef PERL_POISON
+    ((struct perl_memory_debug_header *)where)->size = size;
+    /* FIXME poison the end if it gets shorter.  */
+#  endif
 #endif
 #ifdef DEBUGGING
     if ((long)size < 0)
@@ -180,6 +188,21 @@ Perl_safesysfree(Malloc_t where)
 	    /* int *nowhere = NULL; *nowhere = 0; */
             Perl_croak_nocontext("panic: free from wrong pool");
 	}
+#  ifdef PERL_POISON
+	{
+	    if (((struct perl_memory_debug_header *)where)->in_use
+		== PERL_POISON_FREE) {
+		Perl_croak_nocontext("panic: duplicate free");
+	    }
+	    if (((struct perl_memory_debug_header *)where)->in_use
+		!= PERL_POISON_INUSE) {
+		Perl_croak_nocontext("panic: bad free ");
+	    }
+	    ((struct perl_memory_debug_header *)where)->in_use
+		= PERL_POISON_FREE;
+	}
+	Poison(where, ((struct perl_memory_debug_header *)where)->size, char);
+#  endif
 #endif
 	PerlMem_free(where);
     }
@@ -215,6 +238,10 @@ Perl_safesyscalloc(MEM_SIZE count, MEM_SIZE size)
 	memset((void*)ptr, 0, size);
 #ifdef PERL_TRACK_MEMPOOL
         ((struct perl_memory_debug_header *)ptr)->interpreter = aTHX;
+#  ifdef PERL_POISON
+        ((struct perl_memory_debug_header *)ptr)->size = size;
+        ((struct perl_memory_debug_header *)ptr)->in_use = PERL_POISON_INUSE;
+#  endif
         ptr = (Malloc_t)((char*)ptr+sTHX);
 #endif
 	return ptr;