smbd: split printer reload processing

All printer inventory updates are currently done via
delete_and_reload_printers(), which handles registry.tdb updates for
added or removed printers, AD printer unpublishing on removal, as well
as share service creation and deletion.

This change splits this functionality into two functions such that
per-client smbd processes do not perform registry.tdb updates or printer
unpublishing. This is now only performed by the process that performs
the printcap cache update.

This change is similar to ac6604868d1325dd4c872dc0f6ab056d10ebaecf from
the 3.6 branch.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=10652

Signed-off-by: David Disseldorp <ddiss@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>

1 files changed, 97 insertions, 3 deletions

diff --git a/source3/printing/queue_process.c b/source3/printing/queue_process.c
index 24d361c2bf..88196b4216 100644
--- a/source3/printing/queue_process.c
+++ b/source3/printing/queue_process.c
@@ -33,10 +33,102 @@
 #include "rpc_server/rpc_config.h"
 #include "printing/load.h"
 #include "rpc_server/spoolss/srv_spoolss_nt.h"
+#include "auth.h"
+#include "nt_printing.h"
 
 extern pid_t start_spoolssd(struct tevent_context *ev_ctx,
 			    struct messaging_context *msg_ctx);
 
+/**
+ * @brief Purge stale printers and reload from pre-populated pcap cache.
+ *
+ * This function should normally only be called as a callback on a successful
+ * pcap_cache_reload().
+ *
+ * This function can cause DELETION of printers and drivers from our registry,
+ * so calling it on a failed pcap reload may REMOVE permanently all printers
+ * and drivers.
+ *
+ * @param[in] ev        The event context.
+ *
+ * @param[in] msg_ctx   The messaging context.
+ */
+static void delete_and_reload_printers_full(struct tevent_context *ev,
+					    struct messaging_context *msg_ctx)
+{
+	struct auth_session_info *session_info = NULL;
+	struct spoolss_PrinterInfo2 *pinfo2 = NULL;
+	int n_services;
+	int pnum;
+	int snum;
+	const char *pname;
+	const char *sname;
+	NTSTATUS status;
+
+	n_services = lp_numservices();
+	pnum = lp_servicenumber(PRINTERS_NAME);
+
+	status = make_session_info_system(talloc_tos(), &session_info);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(3, ("reload_printers: "
+			  "Could not create system session_info\n"));
+		/* can't remove stale printers before we
+		 * are fully initilized */
+		return;
+	}
+
+	/*
+	 * Add default config for printers added to smb.conf file and remove
+	 * stale printers
+	 */
+	for (snum = 0; snum < n_services; snum++) {
+		/* avoid removing PRINTERS_NAME */
+		if (snum == pnum) {
+			continue;
+		}
+
+		/* skip no-printer services */
+		if (!snum_is_shared_printer(snum)) {
+			continue;
+		}
+
+		sname = lp_const_servicename(snum);
+		pname = lp_printername(session_info, snum);
+
+		/* check printer, but avoid removing non-autoloaded printers */
+		if (lp_autoloaded(snum) && !pcap_printername_ok(pname)) {
+			DEBUG(3, ("removing stale printer %s\n", pname));
+
+			if (is_printer_published(session_info, session_info,
+						 msg_ctx,
+						 NULL,
+						 lp_servicename(session_info,
+								snum),
+						 &pinfo2)) {
+				nt_printer_publish(session_info,
+						   session_info,
+						   msg_ctx,
+						   pinfo2,
+						   DSPRINT_UNPUBLISH);
+				TALLOC_FREE(pinfo2);
+			}
+			nt_printer_remove(session_info, session_info, msg_ctx,
+					  pname);
+		} else {
+			DEBUG(8, ("Adding default registry entry for printer "
+				  "[%s], if it doesn't exist.\n", sname));
+			nt_printer_add(session_info, session_info, msg_ctx,
+				       sname);
+		}
+	}
+
+	/* finally, purge old snums */
+	delete_and_reload_printers(ev, msg_ctx);
+
+	TALLOC_FREE(session_info);
+}
+
+
 /****************************************************************************
  Notify smbds of new printcap data
 **************************************************************************/
@@ -50,7 +142,7 @@ static void reload_pcap_change_notify(struct tevent_context *ev,
 	 * This will block the process for some time (~1 sec per printer), but
 	 * it doesn't block smbd's servering clients.
 	 */
-	delete_and_reload_printers(ev, msg_ctx);
+	delete_and_reload_printers_full(ev, msg_ctx);
 
 	message_send_all(msg_ctx, MSG_PRINTER_PCAP, NULL, 0, NULL);
 }
@@ -372,7 +464,8 @@ bool printing_subsystem_init(struct tevent_context *ev_ctx,
 		ret = printing_subsystem_queue_tasks(ev_ctx, msg_ctx);
 
 		/* Publish nt printers, this requires a working winreg pipe */
-		pcap_cache_reload(ev_ctx, msg_ctx, &delete_and_reload_printers);
+		pcap_cache_reload(ev_ctx, msg_ctx,
+				  &delete_and_reload_printers_full);
 
 		return ret;
 	}
@@ -401,5 +494,6 @@ void printing_subsystem_update(struct tevent_context *ev_ctx,
 		return;
 	}
 
-	pcap_cache_reload(ev_ctx, msg_ctx, &delete_and_reload_printers);
+	pcap_cache_reload(ev_ctx, msg_ctx,
+			  &delete_and_reload_printers_full);
 }