Revert "Revert "s3-printing: reload shares after pcap cache fill""

This reverts commit 36ea03bbe28122ce03de4969e254dd276cfe5a79.

Signed-off-by: Günther Deschner <gd@samba.org>
(cherry picked from commit 3e1969d229dff2921b43189969dfbe522b167cc2)

6 files changed, 50 insertions, 26 deletions

diff --git a/source3/include/proto.h b/source3/include/proto.h
index 7c2893b1798..46ed4ab07ed 100644
--- a/source3/include/proto.h
+++ b/source3/include/proto.h
@@ -4869,7 +4869,7 @@ void pcap_cache_destroy_specific(struct pcap_cache **ppcache);
 bool pcap_cache_add(const char *name, const char *comment);
 bool pcap_cache_loaded(void);
 void pcap_cache_replace(const struct pcap_cache *cache);
-void pcap_cache_reload(void);
+void pcap_cache_reload(void (*post_cache_fill_fn)(void));
 bool pcap_printername_ok(const char *printername);
 void pcap_printer_fn_specific(const struct pcap_cache *, void (*fn)(const char *, const char *, void *), void *);
 void pcap_printer_fn(void (*fn)(const char *, const char *, void *), void *);
@@ -4880,7 +4880,7 @@ bool aix_cache_reload(void);
 
 /* The following definitions come from printing/print_cups.c  */
 
-bool cups_cache_reload(void);
+bool cups_cache_reload(void (*post_cache_fill_fn)(void));
 bool cups_pull_comment_location(NT_PRINTER_INFO_LEVEL_2 *printer);
 
 /* The following definitions come from printing/print_generic.c  */
diff --git a/source3/printing/load.c b/source3/printing/load.c
index 874f7f25215..00da9cb2921 100644
--- a/source3/printing/load.c
+++ b/source3/printing/load.c
@@ -53,12 +53,11 @@ static void add_auto_printers(void)
 }
 
 /***************************************************************************
-load automatic printer services
+load automatic printer services from pre-populated pcap cache
 ***************************************************************************/
 void load_printers(void)
 {
-	if (!pcap_cache_loaded())
-		pcap_cache_reload();
+	SMB_ASSERT(pcap_cache_loaded());
 
 	add_auto_printers();
 
diff --git a/source3/printing/pcap.c b/source3/printing/pcap.c
index a6bf52a0a4c..0d6480ce015 100644
--- a/source3/printing/pcap.c
+++ b/source3/printing/pcap.c
@@ -125,13 +125,14 @@ void pcap_cache_replace(const struct pcap_cache *pcache)
 	}
 }
 
-void pcap_cache_reload(void)
+void pcap_cache_reload(void (*post_cache_fill_fn)(void))
 {
 	const char *pcap_name = lp_printcapname();
 	bool pcap_reloaded = False;
 	struct pcap_cache *tmp_cache = NULL;
 	XFILE *pcap_file;
 	char *pcap_line;
+	bool post_cache_fill_fn_handled = false;
 
 	DEBUG(3, ("reloading printcap cache\n"));
 
@@ -146,7 +147,12 @@ void pcap_cache_reload(void)
 
 #ifdef HAVE_CUPS
 	if (strequal(pcap_name, "cups")) {
-		pcap_reloaded = cups_cache_reload();
+		pcap_reloaded = cups_cache_reload(post_cache_fill_fn);
+		/*
+		 * cups_cache_reload() is async and calls post_cache_fill_fn()
+		 * on successful completion
+		 */
+		post_cache_fill_fn_handled = true;
 		goto done;
 	}
 #endif
@@ -242,9 +248,13 @@ void pcap_cache_reload(void)
 done:
 	DEBUG(3, ("reload status: %s\n", (pcap_reloaded) ? "ok" : "error"));
 
-	if (pcap_reloaded)
+	if (pcap_reloaded) {
 		pcap_cache_destroy_specific(&tmp_cache);
-	else {
+		if ((post_cache_fill_fn_handled == false)
+		 && (post_cache_fill_fn != NULL)) {
+			post_cache_fill_fn();
+		}
+	} else {
 		pcap_cache_destroy_specific(&pcap_cache);
 		pcap_cache = tmp_cache;
 	}
diff --git a/source3/printing/print_cups.c b/source3/printing/print_cups.c
index e2c8b7e0fbf..a8cc538942e 100644
--- a/source3/printing/print_cups.c
+++ b/source3/printing/print_cups.c
@@ -440,13 +440,19 @@ static bool cups_pcap_load_async(int *pfd)
 	_exit(0);
 }
 
+struct cups_async_cb_args {
+	int pipe_fd;
+	void (*post_cache_fill_fn)(void);
+};
+
 static void cups_async_callback(struct event_context *event_ctx,
 				struct fd_event *event,
 				uint16 flags,
 				void *p)
 {
 	TALLOC_CTX *frame = talloc_stackframe();
-	int fd = *(int *)p;
+	struct cups_async_cb_args *cb_args = (struct cups_async_cb_args *)p;
+	int fd = cb_args->pipe_fd;
 	struct pcap_cache *tmp_pcap_cache = NULL;
 
 	DEBUG(5,("cups_async_callback: callback received for printer data. "
@@ -540,27 +546,36 @@ static void cups_async_callback(struct event_context *event_ctx,
 
 		/* And the systemwide pcap cache. */
 		pcap_cache_replace(local_pcap_copy);
+
+		/* Caller may have requested post cache fill callback */
+		if (cb_args->post_cache_fill_fn) {
+			cb_args->post_cache_fill_fn();
+		}
 	} else {
 		DEBUG(2,("cups_async_callback: failed to read a new "
 			"printer list\n"));
 	}
 	close(fd);
-	TALLOC_FREE(p);
+	TALLOC_FREE(cb_args);
 	TALLOC_FREE(cache_fd_event);
 }
 
-bool cups_cache_reload(void)
+bool cups_cache_reload(void (*post_cache_fill_fn)(void))
 {
-	int *p_pipe_fd = TALLOC_P(NULL, int);
+	struct cups_async_cb_args *cb_args;
+	int *p_pipe_fd;
 
-	if (!p_pipe_fd) {
+	cb_args = TALLOC_P(NULL, struct cups_async_cb_args);
+	if (!cb_args) {
 		return false;
 	}
-
+	cb_args->post_cache_fill_fn = post_cache_fill_fn;
+	p_pipe_fd = &cb_args->pipe_fd;
 	*p_pipe_fd = -1;
 
 	/* Set up an async refresh. */
 	if (!cups_pcap_load_async(p_pipe_fd)) {
+		talloc_free(cb_args);
 		return false;
 	}
 	if (!local_pcap_copy) {
@@ -573,7 +588,7 @@ bool cups_cache_reload(void)
 		cups_async_callback(smbd_event_context(),
 					NULL,
 					EVENT_FD_READ,
-					(void *)p_pipe_fd);
+					(void *)cb_args);
 		if (!local_pcap_copy) {
 			return false;
 		}
@@ -590,10 +605,10 @@ bool cups_cache_reload(void)
 					NULL, *p_pipe_fd,
 					EVENT_FD_READ,
 					cups_async_callback,
-					(void *)p_pipe_fd);
+					(void *)cb_args);
 		if (!cache_fd_event) {
 			close(*p_pipe_fd);
-			TALLOC_FREE(p_pipe_fd);
+			talloc_free(cb_args);
 			return false;
 		}
 	}
diff --git a/source3/smbd/server.c b/source3/smbd/server.c
index 2c5ce400854..72a15fc5575 100644
--- a/source3/smbd/server.c
+++ b/source3/smbd/server.c
@@ -689,9 +689,9 @@ static void smbd_parent_loop(struct smbd_parent_context *parent)
 /* NOTREACHED	return True; */
 }
 
-/****************************************************************************
- Reload printers
-**************************************************************************/
+/***************************************************************************
+ purge stale printers and reload from pre-populated pcap cache
+***************************************************************************/
 void reload_printers(void)
 {
 	int snum;
@@ -699,9 +699,9 @@ void reload_printers(void)
 	int pnum = lp_servicenumber(PRINTERS_NAME);
 	const char *pname;
 
-	pcap_cache_reload();
+	SMB_ASSERT(pcap_cache_loaded());
 
-	/* remove stale printers */
+	DEBUG(10, ("reloading printer services from pcap cache\n"));
 	for (snum = 0; snum < n_services; snum++) {
 		/* avoid removing PRINTERS_NAME or non-autoloaded printers */
 		if (snum == pnum || !(lp_snum_ok(snum) && lp_print_ok(snum) &&
@@ -748,7 +748,7 @@ bool reload_services(bool test)
 
 	ret = lp_load(get_dyn_CONFIGFILE(), False, False, True, True);
 
-	reload_printers();
+	pcap_cache_reload(&reload_printers);
 
 	/* perhaps the config filename is now set */
 	if (!test)
diff --git a/source3/web/swat.c b/source3/web/swat.c
index fceba0f1ee7..b3589568292 100644
--- a/source3/web/swat.c
+++ b/source3/web/swat.c
@@ -564,7 +564,7 @@ static int save_reload(int snum)
                 return 0;
         }
 	iNumNonAutoPrintServices = lp_numservices();
-	load_printers();
+	pcap_cache_reload(&load_printers);
 
 	return 1;
 }
@@ -1547,7 +1547,7 @@ const char *lang_msg_rotate(TALLOC_CTX *ctx, const char *msgid)
 	load_config(True);
 	load_interfaces();
 	iNumNonAutoPrintServices = lp_numservices();
-	load_printers();
+	pcap_cache_reload(&load_printers);
 
 	cgi_setup(get_dyn_SWATDIR(), !demo_mode);