r23806: update Samba4 with the latest ctdb code.

This doesn't get the ctdb code fully working in Samba4, it just gets
it building and not breaking non-clustered use of Samba. It will take
a bit longer to update some of the calling ctdb_cluster.c code to make
it work correctly in Samba4.

Note also that Samba4 now only links to the client portion of
ctdb. For the moment I am leaving the ctdbd as a separate daemon,
which you install separately from http://ctdb.samba.org/.
(This used to be commit b196077cbb55cbecad87065133c2d67198e31066)

1 files changed, 165 insertions, 0 deletions

diff --git a/source4/cluster/ctdb/server/ctdb_lockwait.c b/source4/cluster/ctdb/server/ctdb_lockwait.c
new file mode 100644
index 0000000000..5b0019836e
--- /dev/null
+++ b/source4/cluster/ctdb/server/ctdb_lockwait.c
@@ -0,0 +1,165 @@
+/* 
+   wait for a tdb chain lock
+
+   Copyright (C) Andrew Tridgell  2006
+
+   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 "includes.h"
+#include "lib/events/events.h"
+#include "system/filesys.h"
+#include "system/wait.h"
+#include "db_wrap.h"
+#include "lib/tdb/include/tdb.h"
+#include "../include/ctdb_private.h"
+
+
+struct lockwait_handle {
+	struct ctdb_context *ctdb;
+	struct ctdb_db_context *ctdb_db;
+	struct fd_event *fde;
+	int fd[2];
+	pid_t child;
+	void *private_data;
+	void (*callback)(void *);
+	TDB_DATA key;
+	struct timeval start_time;
+};
+
+static void lockwait_handler(struct event_context *ev, struct fd_event *fde, 
+			     uint16_t flags, void *private_data)
+{
+	struct lockwait_handle *h = talloc_get_type(private_data, 
+						     struct lockwait_handle);
+	void (*callback)(void *) = h->callback;
+	void *p = h->private_data;
+	pid_t child = h->child;
+	TDB_DATA key = h->key;
+	struct tdb_context *tdb = h->ctdb_db->ltdb->tdb;
+	TALLOC_CTX *tmp_ctx = talloc_new(ev);
+
+	key.dptr = talloc_memdup(tmp_ctx, key.dptr, key.dsize);
+
+	talloc_set_destructor(h, NULL);
+	ctdb_latency(&h->ctdb->statistics.max_lockwait_latency, h->start_time);
+	h->ctdb->statistics.pending_lockwait_calls--;
+
+	/* the handle needs to go away when the context is gone - when
+	   the handle goes away this implicitly closes the pipe, which
+	   kills the child holding the lock */
+	talloc_steal(tmp_ctx, h);
+
+	if (h->ctdb->flags & CTDB_FLAG_TORTURE) {
+		if (tdb_chainlock_nonblock(tdb, key) == 0) {
+			ctdb_fatal(h->ctdb, "got chain lock while lockwait child active");
+		}
+	}
+
+	tdb_chainlock_mark(tdb, key);
+	callback(p);
+	tdb_chainlock_unmark(tdb, key);
+
+	kill(child, SIGKILL);
+	waitpid(child, NULL, 0);
+	talloc_free(tmp_ctx);
+}
+
+static int lockwait_destructor(struct lockwait_handle *h)
+{
+	h->ctdb->statistics.pending_lockwait_calls--;
+	kill(h->child, SIGKILL);
+	waitpid(h->child, NULL, 0);
+	return 0;
+}
+
+/*
+  setup a non-blocking chainlock on a tdb record. If this function
+  returns NULL then it could not get the chainlock. Otherwise it
+  returns a opaque handle, and will call callback() once it has
+  managed to get the chainlock. You can cancel it by using talloc_free
+  on the returned handle.
+
+  It is the callers responsibility to unlock the chainlock once
+  acquired
+ */
+struct lockwait_handle *ctdb_lockwait(struct ctdb_db_context *ctdb_db,
+				      TDB_DATA key,
+				      void (*callback)(void *private_data),
+				      void *private_data)
+{
+	struct lockwait_handle *result;
+	int ret;
+	pid_t parent = getpid();
+
+	ctdb_db->ctdb->statistics.lockwait_calls++;
+	ctdb_db->ctdb->statistics.pending_lockwait_calls++;
+
+	if (!(result = talloc_zero(private_data, struct lockwait_handle))) {
+		ctdb_db->ctdb->statistics.pending_lockwait_calls--;
+		return NULL;
+	}
+
+	ret = pipe(result->fd);
+
+	if (ret != 0) {
+		talloc_free(result);
+		ctdb_db->ctdb->statistics.pending_lockwait_calls--;
+		return NULL;
+	}
+
+	result->child = fork();
+
+	if (result->child == (pid_t)-1) {
+		close(result->fd[0]);
+		close(result->fd[1]);
+		talloc_free(result);
+		ctdb_db->ctdb->statistics.pending_lockwait_calls--;
+		return NULL;
+	}
+
+	result->callback = callback;
+	result->private_data = private_data;
+	result->ctdb = ctdb_db->ctdb;
+	result->ctdb_db = ctdb_db;
+	result->key = key;
+
+	if (result->child == 0) {
+		char c = 0;
+		close(result->fd[0]);
+		tdb_chainlock(ctdb_db->ltdb->tdb, key);
+		write(result->fd[1], &c, 1);
+		/* make sure we die when our parent dies */
+		while (kill(parent, 0) == 0 || errno != ESRCH) {
+			sleep(5);
+		}
+		_exit(0);
+	}
+
+	close(result->fd[1]);
+	talloc_set_destructor(result, lockwait_destructor);
+
+	result->fde = event_add_fd(ctdb_db->ctdb->ev, result, result->fd[0],
+				   EVENT_FD_READ|EVENT_FD_AUTOCLOSE, lockwait_handler,
+				   (void *)result);
+	if (result->fde == NULL) {
+		talloc_free(result);
+		ctdb_db->ctdb->statistics.pending_lockwait_calls--;
+		return NULL;
+	}
+
+	result->start_time = timeval_current();
+
+	return result;
+}