Do not assert when debugging SNMP requests with long OIDs (#2150)

    FATAL: assertion failed: MemBuf.cc: "new_cap > (size_t) capacity"

Also fixes repeated same-buffer snmpDebugOid() calls that used to
accumulate stale content in snmpTreeNext():

    snmpTreeNext: Current : .1.3.6.1.4.1.3495
    snmpTreeNext: Next : .1.3.6.1.4.1.3495.1.3.6.1.4.1.3495.1.1.1.0

Current snmpDebugOid() callers have been checked for compatibility with
this fix. Fixing snmpDebugOid() API is out of this surgical fix scope.

diff --git a/src/snmp_core.cc b/src/snmp_core.cc
index a031b8bf6c9dcc3f0b4b62c2c9848f21ed672cc8..db78b1164fa58757dba5e8338d0aaf82d9fe0c19 100644 (file)
--- a/src/snmp_core.cc
+++ b/src/snmp_core.cc
@@ -1065,8 +1065,7 @@ snmpDebugOid(oid * Name, snint Len, MemBuf &outbuf)
 {
     char mbuf[16];
     int x;
-    if (outbuf.isNull())
-        outbuf.init(16, MAX_IPSTRLEN);
+    outbuf.reset();
 
     for (x = 0; x < Len; ++x) {
         size_t bytes = snprintf(mbuf, sizeof(mbuf), ".%u", (unsigned int) Name[x]);