Fix memory leaks in libpqwalreceiver

The results of the libpq functions PQescapeIdentifier() and
PQescapeLiteral() must be freed explicitly.  Also handle errors in these
functions better.

diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
index 7df3698afb24036bcc6d224f8871686e25583687..44a89c73fde9876fe38e650fbc74d92f90db8d94 100644 (file)
--- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
+++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@@ -304,17 +304,30 @@ libpqrcv_startstreaming(WalReceiverConn *conn,
    {
        char   *pubnames_str;
        List   *pubnames;
+       char   *pubnames_literal;
 
        appendStringInfoString(&cmd, " (");
+
        appendStringInfo(&cmd, "proto_version '%u'",
                         options->proto.logical.proto_version);
+
        pubnames = options->proto.logical.publication_names;
        pubnames_str = stringlist_to_identifierstr(conn->streamConn, pubnames);
-       appendStringInfo(&cmd, ", publication_names %s",
-                        PQescapeLiteral(conn->streamConn, pubnames_str,
-                                        strlen(pubnames_str)));
-       appendStringInfoChar(&cmd, ')');
+       if (!pubnames_str)
+           ereport(ERROR,
+                   (errmsg("could not start WAL streaming: %s",
+                           PQerrorMessage(conn->streamConn))));
+       pubnames_literal = PQescapeLiteral(conn->streamConn, pubnames_str,
+                                          strlen(pubnames_str));
+       if (!pubnames_literal)
+           ereport(ERROR,
+                   (errmsg("could not start WAL streaming: %s",
+                           PQerrorMessage(conn->streamConn))));
+       appendStringInfo(&cmd, ", publication_names %s", pubnames_literal);
+       PQfreemem(pubnames_literal);
        pfree(pubnames_str);
+
+       appendStringInfoChar(&cmd, ')');
    }
    else
        appendStringInfo(&cmd, " TIMELINE %u",
@@ -736,14 +749,21 @@ stringlist_to_identifierstr(PGconn *conn, List *strings)
    foreach (lc, strings)
    {
        char *val = strVal(lfirst(lc));
+       char *val_escaped;
 
        if (first)
            first = false;
        else
            appendStringInfoChar(&res, ',');
 
-       appendStringInfoString(&res,
-                              PQescapeIdentifier(conn, val, strlen(val)));
+       val_escaped = PQescapeIdentifier(conn, val, strlen(val));
+       if (!val_escaped)
+       {
+           free(res.data);
+           return NULL;
+       }
+       appendStringInfoString(&res, val_escaped);
+       PQfreemem(val_escaped);
    }
 
    return res.data;