lib: Add server_id_watch_send

This is a brute force variant, trying twice a second. We'll have better
variants with tmsgd in the future.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

diff --git a/source3/lib/server_id_watch.c b/source3/lib/server_id_watch.c
new file mode 100644 (file)
index 0000000..d38241f
--- /dev/null
+++ b/source3/lib/server_id_watch.c
@@ -0,0 +1,105 @@
+/*
+ * Unix SMB/CIFS implementation.
+ * Wait for process death
+ * Copyright (C) Volker Lendecke 2016
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "replace.h"
+#include <tevent.h>
+#include <talloc.h>
+#include "serverid.h"
+#include "server_id_watch.h"
+#include "messages.h"
+#include "lib/util/tevent_unix.h"
+
+struct server_id_watch_state {
+       struct tevent_context *ev;
+       struct server_id pid;
+};
+
+static void server_id_watch_waited(struct tevent_req *subreq);
+
+struct tevent_req *server_id_watch_send(TALLOC_CTX *mem_ctx,
+                                       struct tevent_context *ev,
+                                       struct messaging_context *msg,
+                                       struct server_id pid)
+{
+       struct tevent_req *req, *subreq;
+       struct server_id_watch_state *state;
+
+       req = tevent_req_create(mem_ctx, &state, struct server_id_watch_state);
+       if (req == NULL) {
+               return NULL;
+       }
+       state->ev = ev;
+       state->pid = pid;
+
+       if (!serverid_exists(&state->pid)) {
+               tevent_req_done(req);
+               return tevent_req_post(req, ev);
+       }
+
+       subreq = tevent_wakeup_send(state, ev, timeval_current_ofs(0, 500000));
+       if (tevent_req_nomem(subreq, req)) {
+               return tevent_req_post(req, ev);
+       }
+       tevent_req_set_callback(subreq, server_id_watch_waited, req);
+
+       return req;
+}
+
+static void server_id_watch_waited(struct tevent_req *subreq)
+{
+       struct tevent_req *req = tevent_req_callback_data(
+               subreq, struct tevent_req);
+       struct server_id_watch_state *state = tevent_req_data(
+               req, struct server_id_watch_state);
+       bool ok;
+
+       ok = tevent_wakeup_recv(subreq);
+       TALLOC_FREE(subreq);
+       if (!ok) {
+               tevent_req_oom(req);
+               return;
+       }
+
+       if (!serverid_exists(&state->pid)) {
+               tevent_req_done(req);
+               return;
+       }
+
+       subreq = tevent_wakeup_send(state, state->ev,
+                                   timeval_current_ofs(0, 500000));
+       if (tevent_req_nomem(subreq, req)) {
+               return;
+       }
+       tevent_req_set_callback(subreq, server_id_watch_waited, req);
+}
+
+int server_id_watch_recv(struct tevent_req *req, struct server_id *pid)
+{
+       struct server_id_watch_state *state = tevent_req_data(
+               req, struct server_id_watch_state);
+       int err;
+
+       if (tevent_req_is_unix_error(req, &err)) {
+               return err;
+       }
+       if (pid) {
+               *pid = state->pid;
+       }
+       return 0;
+}

diff --git a/source3/lib/server_id_watch.h b/source3/lib/server_id_watch.h
new file mode 100644 (file)
index 0000000..917dfeb
--- /dev/null
+++ b/source3/lib/server_id_watch.h
@@ -0,0 +1,36 @@
+/*
+ * Unix SMB/CIFS implementation.
+ * Wait for process death
+ * Copyright (C) Volker Lendecke 2016
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __LIB_SERVER_ID_WATCH_H__
+#define __LIB_SERVER_ID_WATCH_H__
+
+#include "replace.h"
+#include <tevent.h>
+#include <talloc.h>
+#include "librpc/gen_ndr/server_id.h"
+
+struct messaging_context;
+
+struct tevent_req *server_id_watch_send(TALLOC_CTX *mem_ctx,
+                                       struct tevent_context *ev,
+                                       struct messaging_context *msg,
+                                       struct server_id pid);
+int server_id_watch_recv(struct tevent_req *req, struct server_id *pid);
+
+#endif

diff --git a/source3/wscript_build b/source3/wscript_build
index 365b25017d4b8e900894743bbeba1eafc90d65b8..b9a2ee60275730264662a7bebf79f687a4af3dd5 100755 (executable)
--- a/source3/wscript_build
+++ b/source3/wscript_build
@@ -317,6 +317,7 @@ bld.SAMBA3_SUBSYSTEM('samba3core',
                    lib/id_cache.c
                    lib/talloc_dict.c
                    lib/serverid.c
+                   lib/server_id_watch.c
                    lib/server_id_db_util.c
                    lib/addrchange.c
                    ../lib/util/debug_s3.c