s3:smbd - Move printing queue stuff

This way we can properly deal with pcap updates in the background queue process
if it is enabled (on by default) and not perform these actions in the main
smbd process.

Signed-off-by: Günther Deschner <gd@samba.org>

1 files changed, 294 insertions, 0 deletions

diff --git a/source3/printing/queue_process.c b/source3/printing/queue_process.c
new file mode 100644
index 0000000000..9fbdd811ab
--- /dev/null
+++ b/source3/printing/queue_process.c
@@ -0,0 +1,294 @@
+/*
+   Unix SMB/Netbios implementation.
+   Version 3.0
+   printing backend routines
+   Copyright (C) Andrew Tridgell 1992-2000
+   Copyright (C) Jeremy Allison 2002
+   Copyright (C) Simo Sorce 2011
+
+   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 "smbd/globals.h"
+#include "include/messages.h"
+#include "printing.h"
+#include "printing/pcap.h"
+#include "serverid.h"
+#include "locking/proto.h"
+#include "smbd/proto.h"
+
+/****************************************************************************
+ Notify smbds of new printcap data
+**************************************************************************/
+static void reload_pcap_change_notify(struct tevent_context *ev,
+			       struct messaging_context *msg_ctx)
+{
+	message_send_all(msg_ctx, MSG_PRINTER_PCAP, NULL, 0, NULL);
+}
+
+static bool print_queue_housekeeping(const struct timeval *now, void *pvt)
+{
+	struct messaging_context *msg_ctx =
+		talloc_get_type_abort(pvt, struct messaging_context);
+	time_t printcap_cache_time = (time_t)lp_printcap_cache_time();
+	time_t t = time_mono(NULL);
+
+	DEBUG(5, ("print queue housekeeping\n"));
+
+	/* if periodic printcap rescan is enabled,
+	 * see if it's time to reload */
+	if ((printcap_cache_time != 0) &&
+	    (t >= (last_printer_reload_time + printcap_cache_time))) {
+		DEBUG( 3,( "Printcap cache time expired.\n"));
+		pcap_cache_reload(messaging_event_context(msg_ctx),
+				  msg_ctx,
+				  &reload_pcap_change_notify);
+		last_printer_reload_time = t;
+	}
+
+	return true;
+}
+
+static bool printing_subsystem_queue_tasks(struct tevent_context *ev_ctx,
+					   struct messaging_context *msg_ctx)
+{
+	if (!(event_add_idle(ev_ctx, NULL,
+			     timeval_set(SMBD_HOUSEKEEPING_INTERVAL, 0),
+			     "print_queue_housekeeping",
+			     print_queue_housekeeping,
+			     msg_ctx))) {
+		DEBUG(0, ("Could not add print_queue_housekeeping event\n"));
+		return false;
+	}
+
+	return true;
+}
+
+static void bq_sig_term_handler(struct tevent_context *ev,
+				struct tevent_signal *se,
+				int signum,
+				int count,
+				void *siginfo,
+				void *private_data)
+{
+	exit_server_cleanly("termination signal");
+}
+
+void bq_setup_sig_term_handler(void)
+{
+	struct tevent_signal *se;
+
+	se = tevent_add_signal(server_event_context(),
+			       server_event_context(),
+			       SIGTERM, 0,
+			       bq_sig_term_handler,
+			       NULL);
+	if (!se) {
+		exit_server("failed to setup SIGTERM handler");
+	}
+}
+
+static void bq_sig_hup_handler(struct tevent_context *ev,
+				struct tevent_signal *se,
+				int signum,
+				int count,
+				void *siginfo,
+				void *pvt)
+{
+	struct messaging_context *msg_ctx;
+
+	msg_ctx = talloc_get_type_abort(pvt, struct messaging_context);
+	change_to_root_user();
+
+	DEBUG(1, ("Reloading pcap cache after SIGHUP\n"));
+	pcap_cache_reload(ev, msg_ctx, &reload_pcap_change_notify);
+}
+
+static void bq_setup_sig_hup_handler(struct tevent_context *ev,
+				     struct messaging_context *msg_ctx)
+{
+	struct tevent_signal *se;
+
+	se = tevent_add_signal(ev, ev, SIGHUP, 0, bq_sig_hup_handler,
+			       msg_ctx);
+	if (!se) {
+		exit_server("failed to setup SIGHUP handler");
+	}
+}
+
+static void bq_smb_conf_updated(struct messaging_context *msg_ctx,
+				void *private_data,
+				uint32_t msg_type,
+				struct server_id server_id,
+				DATA_BLOB *data)
+{
+	struct tevent_context *ev_ctx =
+		talloc_get_type_abort(private_data, struct tevent_context);
+
+	DEBUG(10,("smb_conf_updated: Got message saying smb.conf was "
+		  "updated. Reloading.\n"));
+	change_to_root_user();
+	pcap_cache_reload(ev_ctx, msg_ctx, &reload_pcap_change_notify);
+}
+
+static void printing_pause_fd_handler(struct tevent_context *ev,
+				      struct tevent_fd *fde,
+				      uint16_t flags,
+				      void *private_data)
+{
+	/*
+	 * If pause_pipe[1] is closed it means the parent smbd
+	 * and children exited or aborted.
+	 */
+	exit_server_cleanly(NULL);
+}
+
+extern struct child_pid *children;
+extern int num_children;
+
+static void add_child_pid(pid_t pid)
+{
+	struct child_pid *child;
+
+        child = SMB_MALLOC_P(struct child_pid);
+        if (child == NULL) {
+                DEBUG(0, ("Could not add child struct -- malloc failed\n"));
+                return;
+        }
+        child->pid = pid;
+        DLIST_ADD(children, child);
+        num_children += 1;
+}
+
+pid_t background_lpq_updater_pid = -1;
+
+/****************************************************************************
+main thread of the background lpq updater
+****************************************************************************/
+static void start_background_queue(struct tevent_context *ev,
+				   struct messaging_context *msg_ctx)
+{
+	/* Use local variables for this as we don't
+	 * need to save the parent side of this, just
+	 * ensure it closes when the process exits.
+	 */
+	int pause_pipe[2];
+
+	DEBUG(3,("start_background_queue: Starting background LPQ thread\n"));
+
+	if (pipe(pause_pipe) == -1) {
+		DEBUG(5,("start_background_queue: cannot create pipe. %s\n", strerror(errno) ));
+		exit(1);
+	}
+
+	background_lpq_updater_pid = sys_fork();
+
+	if (background_lpq_updater_pid == -1) {
+		DEBUG(5,("start_background_queue: background LPQ thread failed to start. %s\n", strerror(errno) ));
+		exit(1);
+	}
+
+	/* Track the printing pid along with other smbd children */
+	add_child_pid(background_lpq_updater_pid);
+
+	if(background_lpq_updater_pid == 0) {
+		struct tevent_fd *fde;
+		int ret;
+		NTSTATUS status;
+
+		/* Child. */
+		DEBUG(5,("start_background_queue: background LPQ thread started\n"));
+
+		close(pause_pipe[0]);
+		pause_pipe[0] = -1;
+
+		status = reinit_after_fork(msg_ctx, ev, procid_self(), true);
+
+		if (!NT_STATUS_IS_OK(status)) {
+			DEBUG(0,("reinit_after_fork() failed\n"));
+			smb_panic("reinit_after_fork() failed");
+		}
+
+		bq_setup_sig_term_handler();
+		bq_setup_sig_hup_handler(ev, msg_ctx);
+
+		if (!printing_subsystem_queue_tasks(ev, msg_ctx)) {
+			exit(1);
+		}
+
+		if (!serverid_register(procid_self(),
+				       FLAG_MSG_GENERAL|FLAG_MSG_SMBD
+				       |FLAG_MSG_PRINT_GENERAL)) {
+			exit(1);
+		}
+
+		if (!locking_init()) {
+			exit(1);
+		}
+
+		messaging_register(msg_ctx, ev, MSG_SMB_CONF_UPDATED,
+				   bq_smb_conf_updated);
+		messaging_register(msg_ctx, NULL, MSG_PRINTER_UPDATE,
+				   print_queue_receive);
+
+		fde = tevent_add_fd(ev, ev, pause_pipe[1], TEVENT_FD_READ,
+				    printing_pause_fd_handler,
+				    NULL);
+		if (!fde) {
+			DEBUG(0,("tevent_add_fd() failed for pause_pipe\n"));
+			smb_panic("tevent_add_fd() failed for pause_pipe");
+		}
+
+		DEBUG(5,("start_background_queue: background LPQ thread waiting for messages\n"));
+		ret = tevent_loop_wait(ev);
+		/* should not be reached */
+		DEBUG(0,("background_queue: tevent_loop_wait() exited with %d - %s\n",
+			 ret, (ret == 0) ? "out of events" : strerror(errno)));
+		exit(1);
+	}
+
+	close(pause_pipe[1]);
+}
+
+static bool use_background_queue;
+
+/* Run before the parent forks */
+bool printing_subsystem_init(struct tevent_context *ev_ctx,
+			     struct messaging_context *msg_ctx,
+			     bool background_queue)
+{
+	bool ret = true;
+
+	use_background_queue = background_queue;
+
+	/* Publish nt printers, this requires a working winreg pipe */
+	pcap_cache_reload(ev_ctx, msg_ctx, &reload_printers);
+
+	if (background_queue) {
+		start_background_queue(ev_ctx, msg_ctx);
+	} else {
+		ret = printing_subsystem_queue_tasks(ev_ctx, msg_ctx);
+	}
+
+	return ret;
+}
+
+void printing_subsystem_update(struct tevent_context *ev_ctx,
+			       struct messaging_context *msg_ctx)
+{
+	if (use_background_queue) return;
+
+	pcap_cache_reload(ev_ctx, msg_ctx, &reload_pcap_change_notify);
+}