Rename "format_value()" to "format_var()", and have it dynamically

allocate the buffer into which it formats the variable value, and return
that value.  This

	1) makes it more closely resemble the formatting routine in the
	   libsmi-based "packet-snmp.c" under development;

	2) makes it less likely to overrun the buffer (we can't be
	   certain how long the string "sprint_value()" generates will
	   be, but we can make a reasonable guess as to the maximum size
	   based on the type and size of the object we're formatting).

When *not* using "-lsnmp", dynamically allocate the buffers into which
we format octet strings and OID values, based on the size of the object
we're formatting, so that we don't overrun the buffer.

svn path=/trunk/; revision=2091

1 files changed, 60 insertions, 9 deletions

diff --git a/packet-snmp.c b/packet-snmp.c
index a92a9512d0..55cd3e4684 100644
--- a/packet-snmp.c
+++ b/packet-snmp.c
@@ -2,7 +2,7 @@
  * Routines for SNMP (simple network management protocol)
  * D.Jorand (c) 1998
  *
- * $Id: packet-snmp.c,v 1.38 2000/06/25 20:55:09 guy Exp $
+ * $Id: packet-snmp.c,v 1.39 2000/06/26 00:13:21 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -569,10 +569,49 @@ format_oid(gchar *buf, subid_t *oid, guint oid_length)
 }
 
 #ifdef HAVE_SPRINT_VALUE
-static void
-format_value(gchar *buf, struct variable_list *variable, subid_t *variable_oid,
+static gchar *
+format_var(struct variable_list *variable, subid_t *variable_oid,
     guint variable_oid_length, gushort vb_type, guint vb_length)
 {
+	gchar *buf;
+
+	switch (vb_type) {
+
+	case SNMP_INTEGER:
+	case SNMP_COUNTER:
+	case SNMP_GAUGE:
+	case SNMP_TIMETICKS:
+		/* We don't know how long this will be, but let's guess it
+		   fits within 128 characters; that should be enough for an
+		   integral value plus some sort of type indication. */
+		buf = g_malloc(128);
+		break;
+
+	case SNMP_OCTETSTR:
+	case SNMP_IPADDR:
+	case SNMP_OPAQUE:
+	case SNMP_NSAP:
+	case SNMP_BITSTR:
+	case SNMP_COUNTER64:
+		/* We don't know how long this will be, but let's guess it
+		   fits within 128 characters plus 4 characters per octet. */
+		buf = g_malloc(128 + 4*vb_length);
+		break;
+
+	case SNMP_OBJECTID:
+		/* We don't know how long this will be, but let's guess it
+		   fits within 128 characters plus 32 characters per subid
+		   (10 digits plus period, or a subid name). */
+		buf = g_malloc(1024 + 32*vb_length);
+		break;
+
+	default:
+		/* Should not happen. */
+		g_assert_not_reached();
+		buf = NULL;
+		break;
+	}
+
 	variable->next_variable = NULL;
 	variable->name = variable_oid;
 	variable->name_length = variable_oid_length;
@@ -612,6 +651,7 @@ format_value(gchar *buf, struct variable_list *variable, subid_t *variable_oid,
 
 	case SNMP_OBJECTID:
 		variable->type = VALTYPE_OBJECTID;
+		vb_length *= sizeof (subid_t);	/* XXX - necessary? */
 		break;
 
 	case SNMP_BITSTR:
@@ -623,7 +663,9 @@ format_value(gchar *buf, struct variable_list *variable, subid_t *variable_oid,
 		break;
 	}
 	variable->val_len = vb_length;
+
 	sprint_value(buf, variable_oid, variable_oid_length, variable);
+	return buf;
 }
 #endif
 
@@ -648,7 +690,7 @@ snmp_variable_decode(proto_tree *snmp_tree, subid_t *variable_oid,
 	subid_t *vb_oid;
 	guint vb_oid_length;
 
-	gchar vb_display_string[MAX_STRING_LEN]; /* TBC */
+	gchar *vb_display_string;
 
 #ifdef HAVE_SPRINT_VALUE
 	struct variable_list variable;
@@ -697,11 +739,12 @@ snmp_variable_decode(proto_tree *snmp_tree, subid_t *variable_oid,
 #elif defined(HAVE_SNMP_SNMP_H)
 			variable.val.integer = &vb_integer_value;
 #endif
-			format_value(vb_display_string, &variable,
+			vb_display_string = format_var(&variable,
 			    variable_oid, variable_oid_length, vb_type,
 			    vb_length);
 			proto_tree_add_text(snmp_tree, NullTVB, offset, length,
 			    "Value: %s", vb_display_string);
+			g_free(vb_display_string);
 #else
 			proto_tree_add_text(snmp_tree, NullTVB, offset, length,
 			    "Value: %s: %d (%#x)", vb_type_name,
@@ -726,11 +769,12 @@ snmp_variable_decode(proto_tree *snmp_tree, subid_t *variable_oid,
 #elif defined(HAVE_SNMP_SNMP_H)
 			variable.val.integer = &vb_uinteger_value;
 #endif
-			format_value(vb_display_string, &variable,
+			vb_display_string = format_var(&variable,
 			    variable_oid, variable_oid_length, vb_type,
 			    vb_length);
 			proto_tree_add_text(snmp_tree, NullTVB, offset, length,
 			    "Value: %s", vb_display_string);
+			g_free(vb_display_string);
 #else
 			proto_tree_add_text(snmp_tree, NullTVB, offset, length,
 			    "Value: %s: %u (%#x)", vb_type_name,
@@ -753,11 +797,12 @@ snmp_variable_decode(proto_tree *snmp_tree, subid_t *variable_oid,
 		if (snmp_tree) {
 #ifdef HAVE_SPRINT_VALUE
 			variable.val.string = vb_octet_string;
-			format_value(vb_display_string, &variable,
+			vb_display_string = format_var(&variable,
 			    variable_oid, variable_oid_length, vb_type,
 			    vb_length);
 			proto_tree_add_text(snmp_tree, NullTVB, offset, length,
 			    "Value: %s", vb_display_string);
+			g_free(vb_display_string);
 #else
 			/*
 			 * If some characters are not printable, display
@@ -774,6 +819,7 @@ snmp_variable_decode(proto_tree *snmp_tree, subid_t *variable_oid,
 				 * character, before we got to the end
 				 * of the string.
 				 */
+				vb_display_string = g_malloc(4*vb_length);
 				buf = &vb_display_string[0];
 				len = sprintf(buf, "%03u", vb_octet_string[0]);
 				buf += len;
@@ -785,6 +831,7 @@ snmp_variable_decode(proto_tree *snmp_tree, subid_t *variable_oid,
 				proto_tree_add_text(snmp_tree, NullTVB, offset, length,
 				    "Value: %s: %s", vb_type_name,
 				    vb_display_string);
+				g_free(vb_display_string);
 			} else {
 				proto_tree_add_text(snmp_tree, NullTVB, offset, length,
 				    "Value: %s: %.*s", vb_type_name,
@@ -815,16 +862,20 @@ snmp_variable_decode(proto_tree *snmp_tree, subid_t *variable_oid,
 		if (snmp_tree) {
 #ifdef HAVE_SPRINT_VALUE
 			variable.val.objid = vb_oid;
-			format_value(vb_display_string, &variable,
+			vb_display_string = format_var(&variable,
 			    variable_oid, variable_oid_length, vb_type,
-			    vb_length*sizeof (subid_t));
+			    vb_length);
 			proto_tree_add_text(snmp_tree, NullTVB, offset, length,
 			    "Value: %s", vb_display_string);
 #else
+			/* This fits with 11 characters per subid (10 digits
+			   plus period). */
+			vb_display_string = g_malloc(11*vb_oid_length);
 			format_oid(vb_display_string, vb_oid, vb_oid_length);
 			proto_tree_add_text(snmp_tree, NullTVB, offset, length,
 			    "Value: %s: %s", vb_type_name, vb_display_string);
 #endif
+			g_free(vb_display_string);
 		}
 		g_free(vb_oid);
 		break;