[or-cvs] Try to find out early if buffers get trashed or double-freed.

[Nick Mathewson]

Update of /home/or/cvsroot/src/or
In directory moria.mit.edu:/tmp/cvs-serv28111/or

Modified Files:
	buffers.c connection.c or.h 
Log Message:
Try to find out early if buffers get trashed or double-freed.

Index: buffers.c
===================================================================
RCS file: /home/or/cvsroot/src/or/buffers.c,v
retrieving revision 1.66
retrieving revision 1.67
diff -u -d -r1.66 -r1.67
--- buffers.c	28 Feb 2004 19:14:11 -0000	1.66
+++ buffers.c	3 Mar 2004 22:49:15 -0000	1.67
@@ -6,7 +6,9 @@
 
 #include "or.h"
 
+#define BUFFER_MAGIC 0xB0FFF312u
 struct buf_t {
+  uint32_t magic; /* for debugging */
   char *mem;
   size_t len;
   size_t datalen;
@@ -118,6 +120,7 @@
 buf_t *buf_new_with_capacity(size_t size) {
   buf_t *buf;
   buf = (buf_t*)tor_malloc(sizeof(buf_t));
+  buf->magic = BUFFER_MAGIC;
   buf->mem = (char *)tor_malloc(size);
   buf->len = size;
   buf->datalen = 0;
@@ -153,9 +156,10 @@
 }
 
 void buf_free(buf_t *buf) {
-  assert(buf && buf->mem);
-  free(buf->mem);
-  free(buf);
+  assert_buf_ok(buf);
+  buf->magic = 0xDEADBEEF;
+  tor_free(buf->mem);
+  tor_free(buf);
 }
 
 /* read from socket s, writing onto end of buf.
@@ -576,6 +580,14 @@
   }
 }
 
+void assert_buf_ok(buf_t *buf)
+{
+  assert(buf);
+  assert(buf->magic == BUFFER_MAGIC);
+  assert(buf->mem);
+  assert(buf->datalen <= buf->len);
+}
+
 /*
   Local Variables:
   mode:c

Index: connection.c
===================================================================
RCS file: /home/or/cvsroot/src/or/connection.c,v
retrieving revision 1.174
retrieving revision 1.175
diff -u -d -r1.174 -r1.175
--- connection.c	3 Mar 2004 08:46:18 -0000	1.174
+++ connection.c	3 Mar 2004 22:49:15 -0000	1.175
@@ -866,8 +866,8 @@
 
   /* buffers */
   if (!connection_is_listener(conn)) {
-    assert(conn->inbuf);
-    assert(conn->outbuf);
+    assert_buf_ok(conn->inbuf);
+    assert_buf_ok(conn->outbuf);
   }
 
   assert(!now || conn->timestamp_lastread <= now);

Index: or.h
===================================================================
RCS file: /home/or/cvsroot/src/or/or.h,v
retrieving revision 1.243
retrieving revision 1.244
diff -u -d -r1.243 -r1.244
--- or.h	3 Mar 2004 05:08:01 -0000	1.243
+++ or.h	3 Mar 2004 22:49:15 -0000	1.244
@@ -572,6 +572,8 @@
                         char **body_out, int max_bodylen);
 int fetch_from_buf_socks(buf_t *buf, socks_request_t *req);
 
+void assert_buf_ok(buf_t *buf);
+
 /********************************* circuit.c ***************************/
 
 void circuit_add(circuit_t *circ);