1 files changed, 81 insertions, 0 deletions
diff --git a/lib/libmalloc/verify.c b/lib/libmalloc/verify.c
new file mode 100644
index 0000000000000..9fbad097b986a
--- /dev/null
+++ b/lib/libmalloc/verify.c
@@ -0,0 +1,81 @@
+/*  Author: Mark Moraes <moraes@csri.toronto.edu> */
+
+/*LINTLIBRARY*/
+
+#include "defs.h"
+#include "globals.h"
+
+RCSID("$Id: verify.c,v 1.1 1994/03/06 22:59:57 nate Exp $")
+
+/*
+ *  Goes through the entire heap checking all pointers, tags for
+ *  consistency. Should catch most casual heap corruption (overwriting
+ *  the end of a malloc'ed chunk, etc..) Nonetheless, heap corrupters
+ *  tend to be devious and ingenious in ways they corrupt heaps (Believe
+ *  me, I know:-). We should probably do the same thing if DEBUG is not
+ *  defined, but return 0 instead of aborting. If fullcheck is non-zero,
+ *  it also checks that free blocks contain the magic pattern written
+ *  into them when they were freed to make sure the program is not still
+ *  trying to access those blocks.
+ */
+int
+mal_verify(fullcheck)
+int fullcheck;
+{
+#ifdef DEBUG
+	REGISTER Word *ptr;
+	REGISTER Word *blk;
+	REGISTER Word *blkend;
+
+	if (_malloc_loword == NULL) /* Nothing malloc'ed yet */
+		return(0);
+		
+	if (_malloc_rover != NULL) {
+		ASSERT(PTR_IN_HEAP(_malloc_rover),
+		 "corrupt ROVER pointer found by mal_verify()");
+		ASSERT(VALID_END_SIZE_FIELD(_malloc_rover),
+		 "corrupt ROVER SIZE field found by mal_verify()");
+		ASSERT(VALID_NEXT_PTR(_malloc_rover),
+		 "corrupt ROVER NEXT pointer found by mal_verify()");
+		ASSERT(VALID_PREV_PTR(_malloc_rover),
+		 "corrupt ROVER PREV pointer found by mal_verify()");
+	}
+	for(ptr = _malloc_mem; ptr != NULL; ptr = ptr->next) {
+		/*
+		 *  Check arena bounds - not same as checking block tags,
+		 *  despite similar appearance of the test
+		 */
+		ASSERT(SIZEFIELD(ptr+1) == SIZEFIELD(ptr + SIZE(ptr+1)),
+		 "corrupt malloc arena found by mal_verify");
+		blkend = ptr + SIZE(ptr + 1);
+		for(blk = ptr + ARENASTART; blk < blkend; blk += SIZE(blk)) {
+			ASSERT(PTR_IN_HEAP(blk), "corrupt pointer found by mal_verify()");
+			ASSERT(VALID_START_SIZE_FIELD(blk),
+			 "corrupt SIZE field found by mal_verify()");
+			if (TAG(blk) == FREE) {
+				ASSERT(VALID_NEXT_PTR(blk + FREESIZE(blk) - 1),
+				 "corrupt NEXT pointer found by mal_verify()");
+				ASSERT(VALID_PREV_PTR(blk + FREESIZE(blk) - 1),
+				 "corrupt PREV pointer found by mal_verify()");
+				if (fullcheck) {
+					/* Make sure all free blocks are filled with FREEMAGIC */
+					int i, n;
+					char *cp;
+
+					n = (SIZE(blk) - FREE_OVERHEAD) *
+					 sizeof(Word);
+					cp = (char *) (blk + FREEHEADERWORDS);
+					for (i = 0; i < n; i++, cp++) {
+						ASSERT(*cp == FREEMAGIC,
+						 "corrupt free block found by mal_verify()");
+					}
+				}
+			} else {
+				ASSERT(VALID_MAGIC(blk),
+				 "overwritten end of block found by mal_verify()");
+			}
+		}
+	}
+#endif /* DEBUG */
+	return(0);
+}