Fix pg_GSS_error to use conn->errorMessage more sanely, ie, actually

work with the PQExpBuffer code instead of fighting it.  This avoids an
unnecessary limit on message length and fixes the latent bug that
errorMessage.len wasn't getting set.

src/interfaces/libpq/fe-auth.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/interfaces/libpq/fe-auth.c,v 1.136 2008/01/01 19:46:00 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/interfaces/libpq/fe-auth.c,v 1.137 2008/01/31 18:58:30 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -340,14 +340,12 @@ static GSS_DLLIMP gss_OID GSS_C_NT_HOSTBASED_SERVICE = &GSS_C_NT_HOSTBASED_SERVI
 #endif
 
 /*
- * Fetch all errors of a specific type that fit into a buffer
- * and append them.
+ * Fetch all errors of a specific type and append to "str".
  */
 static void
-pg_GSS_error_int(char *mprefix, char *msg, int msglen,
+pg_GSS_error_int(PQExpBuffer str, const char *mprefix,
 				 OM_uint32 stat, int type)
 {
-	int			curlen = 0;
 	OM_uint32	lmaj_s,
 				lmin_s;
 	gss_buffer_desc lmsg;
@@ -357,36 +355,25 @@ pg_GSS_error_int(char *mprefix, char *msg, int msglen,
 	{
 		lmaj_s = gss_display_status(&lmin_s, stat, type,
 									GSS_C_NO_OID, &msg_ctx, &lmsg);
-
-		if (curlen < msglen)
-		{
-			snprintf(msg + curlen, msglen - curlen, "%s: %s\n",
-					 mprefix, (char *) lmsg.value);
-			curlen += lmsg.length;
-		}
+		appendPQExpBuffer(str, "%s: %s\n", mprefix, (char *) lmsg.value);
 		gss_release_buffer(&lmin_s, &lmsg);
 	} while (msg_ctx);
 }
 
 /*
- * GSSAPI errors contains two parts. Put as much as possible of
- * both parts into the string.
+ * GSSAPI errors contain two parts; put both into conn->errorMessage.
  */
 static void
-pg_GSS_error(char *mprefix, PGconn *conn,
+pg_GSS_error(const char *mprefix, PGconn *conn,
 			 OM_uint32 maj_stat, OM_uint32 min_stat)
 {
-	int			mlen;
+	resetPQExpBuffer(&conn->errorMessage);
 
 	/* Fetch major error codes */
-	pg_GSS_error_int(mprefix, conn->errorMessage.data,
-					 conn->errorMessage.maxlen, maj_stat, GSS_C_GSS_CODE);
-	mlen = strlen(conn->errorMessage.data);
-
-	/* If there is room left, try to add the minor codes as well */
-	if (mlen < conn->errorMessage.maxlen - 1)
-		pg_GSS_error_int(mprefix, conn->errorMessage.data + mlen,
-				conn->errorMessage.maxlen - mlen, min_stat, GSS_C_MECH_CODE);
+	pg_GSS_error_int(&conn->errorMessage, mprefix, maj_stat, GSS_C_GSS_CODE);
+
+	/* Add the minor codes as well */
+	pg_GSS_error_int(&conn->errorMessage, mprefix, min_stat, GSS_C_MECH_CODE);
 }
 
 /*