--- ray/src/common/malloc.c	1990/12/04 20:46:46	1.11
+++ ray/src/common/malloc.c	1991/07/17 11:35:47	1.13
@@ -1,4 +1,4 @@
-/* Copyright (c) 1990 Regents of the University of California */
+/* Copyright (c) 1991 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -46,18 +46,25 @@ static unsigned	m_nwasted = 0;
 					/* malloc free lists */
 typedef union m_head {
 	union m_head	*next;
-	int		bucket;
+	struct {
+		short		magic;
+		short		bucket;
+	}	a;
 	ALIGN		dummy;
 } M_HEAD;
 
+#define MAGIC		0x1a2		/* magic number for allocated memory */
+
 #define FIRSTBUCKET	3
 #define NBUCKETS	30
 
 static M_HEAD	*free_list[NBUCKETS];
 
-static char	DUMMYLOC[BYTES_WORD];
+static ALIGN	dummy_mem;
 
+#define DUMMYLOC	((char *)&dummy_mem)
 
+
 char *
 mscrounge(np)		/* search free lists to satisfy request */
 register unsigned	*np;
@@ -94,9 +101,6 @@ register unsigned  n;
 	unsigned  thisamnt;
 	register char	*p;
 
-#ifdef MSTATS
-	b_nalloced += n;
-#endif
 	if (pagesz == 0) {				/* initialize */
 		pagesz = amnt = getpagesize();
 		nrem = (int)sbrk(0);			/* page align break */
@@ -132,6 +136,9 @@ register unsigned  n;
 	p = bpos;
 	bpos += n;					/* advance */
 	nrem -= n;
+#ifdef MSTATS
+	b_nalloced += n;
+#endif
 	return(p);
 }
 
@@ -184,10 +191,6 @@ unsigned	n;
 		errno = EINVAL;
 		return(NULL);
 	}
-#ifdef MSTATS
-	m_nalloced += bsiz + sizeof(M_HEAD);
-	m_nwasted += bsiz + sizeof(M_HEAD) - n;
-#endif
 	if (free_list[bucket] == NULL) {	/* need more core */
 		mp = (M_HEAD *)bmalloc(bsiz+sizeof(M_HEAD));
 		if (mp == NULL)
@@ -196,7 +199,12 @@ unsigned	n;
 		mp = free_list[bucket];
 		free_list[bucket] = mp->next;
 	}
-	mp->bucket = bucket;			/* tag block */
+#ifdef MSTATS
+	m_nalloced += bsiz + sizeof(M_HEAD);
+	m_nwasted += bsiz + sizeof(M_HEAD) - n;
+#endif
+	mp->a.magic = MAGIC;			/* tag block */
+	mp->a.bucket = bucket;
 	return((char *)(mp+1));
 }
 
@@ -209,20 +217,22 @@ unsigned	n;
 	char	*p;
 	register unsigned	on;
 					/* get old size */
-	if (op != NULL && op != DUMMYLOC)
-		on = 1 << ((M_HEAD *)op-1)->bucket;
+	if (op != NULL && op != DUMMYLOC && ((M_HEAD *)op-1)->a.magic == MAGIC)
+		on = 1 << ((M_HEAD *)op-1)->a.bucket;
 	else
 		on = 0;
 	if (n <= on && (n > on>>1 || on == 1<<FIRSTBUCKET))
 		return(op);		/* same bucket */
-	p = malloc(n);
-	if (p != NULL)
+	if ((p = malloc(n)) == NULL)
+		return(NULL);
+	if (on) {
 #ifdef  BSD
 		bcopy(op, p, n>on ? on : n);
 #else
 		(void)memcpy(p, op, n>on ? on : n);
 #endif
-	free(op);
+		free(op);
+	}
 	return(p);
 }
 
@@ -234,14 +244,17 @@ char	*p;
 	register int	bucket;
 
 	if (p == NULL || p == DUMMYLOC)
-		return;
+		return(1);
 	mp = (M_HEAD *)p - 1;
-	bucket = mp->bucket;
+	if (mp->a.magic != MAGIC)		/* sanity check */
+		return(0);
+	bucket = mp->a.bucket;
 	mp->next = free_list[bucket];
 	free_list[bucket] = mp;
 #ifdef MSTATS
 	m_nfreed += (1 << bucket) + sizeof(M_HEAD);
 #endif
+	return(1);
 }