Attachment 16596 Details for Bug 13214 – The patch on Github mentioned in the comments

[patch] The patch on Github mentioned in the comments

bug-13214-from-github.patch (text/plain), 3.89 KB, created by Douglas Bagnall on 2021-04-23 04:19:54 UTC

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Creator: Douglas Bagnall

Created: 2021-04-23 04:19:54 UTC

Size: 3.89 KB

patch

obsolete

>From c6f07622e89827c3b88e031c93ca1b06fd4924b0 Mon Sep 17 00:00:00 2001
>From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <kristjan@rvx.is>
>Date: Tue, 30 Jan 2018 17:14:50 +0000
>Subject: [PATCH] bind9_dlz fix:  support named reload
>
>https://bugzilla.samba.org/show_bug.cgi?id=13214
>
>Using a singleton instance makes samba_dlz break when named does a "reload".
>Remove the singleton management and allow named to initialize a new
>samba_dlz_state and destroy the old on reload.
>
>bind does a "reload" of a dlz module by:
>
> 1. Creating a new dlz instance state via dlz_create()
> 2. Initializing it with dlz_configure()
> 3. Deleting the old instance state via dlz_destroy().
>
>Using a singleton instance would cause samba_dlz to fail after a reload.
>I don't know the precise reason, here are two possibles:
>
> - dlz_configure() on an already running instance would break it somehow.
> - Returning the same pointer from dlz_create() as the one already running may
>   confuse the internal bookkeeping in bind. Notice how a new instance is
>   created before the old is destroyed.
>
>Note: This effectively undoes revision 34eab45.  The issues with 'state->samdb'
>      seem to have been gone away.  newstate->samdb is a talloc_reference() of
>      oldstate->samdb() and thus has proper refcounts.  talloc_free(oldstate)
>      does not invalidate it.
>
>Signed-off-by: kristj?n Valur J?nssons <kristjan@rvx.is>
>---
> source4/dns_server/dlz_bind9.c | 29 ++++++++++++++++++++++++++---
> 1 file changed, 26 insertions(+), 3 deletions(-)
>
>diff --git a/source4/dns_server/dlz_bind9.c b/source4/dns_server/dlz_bind9.c
>index 6ef378c75a6b..7aaa7463aefb 100644
>--- a/source4/dns_server/dlz_bind9.c
>+++ b/source4/dns_server/dlz_bind9.c
>@@ -40,6 +40,16 @@
> #include "dlz_minimal.h"
> #include "dns_server/dnsserver_common.h"
> 
>+/* 
>+ * maintaining a singleton will break the 'reload' functionality
>+ * triggered by 'rndc reload' and 'service reload named' which
>+ * is used e.g. by logrotate.  It can be enabled by defining the following
>+ * preprocessor macro
>+ */
>+#ifndef DLZ_BIND9_USE_SINGLETON
>+#define DLS_BIND9_USE_SINGLETON 0
>+#endif
>+
> struct b9_options {
> 	const char *url;
> 	const char *debug;
>@@ -72,8 +82,10 @@ struct dlz_bind9_data {
> 	dns_dlz_writeablezone_t *writeable_zone;
> };
> 
>+#if DLZ_BIND9_USE_SINGLETON
> static struct dlz_bind9_data *dlz_bind9_state = NULL;
> static int dlz_bind9_state_ref_count = 0;
>+#endif
> 
> static const char *zone_prefixes[] = {
> 	"CN=MicrosoftDNS,DC=DomainDnsZones",
>@@ -615,11 +627,13 @@ _PUBLIC_ isc_result_t dlz_create(const char *dlzname,
> 	struct ldb_dn *dn;
> 	NTSTATUS nt_status;
> 
>+#if DLZ_BIND9_USE_SINGLETON
> 	if (dlz_bind9_state != NULL) {
> 		*dbdata = dlz_bind9_state;
> 		dlz_bind9_state_ref_count++;
> 		return ISC_R_SUCCESS;
> 	}
>+#endif
> 
> 	state = talloc_zero(NULL, struct dlz_bind9_data);
> 	if (state == NULL) {
>@@ -635,6 +649,8 @@ _PUBLIC_ isc_result_t dlz_create(const char *dlzname,
> 	}
> 	va_end(ap);
> 
>+	state->log(ISC_LOG_INFO, "samba_dlz: starting for instance %p", state);
>+
> 	/* Do not install samba signal handlers */
> 	fault_setup_disable();
> 
>@@ -715,8 +731,11 @@ _PUBLIC_ isc_result_t dlz_create(const char *dlzname,
> 	state->auth_context->generate_session_info_pac = b9_generate_session_info_pac;
> 
> 	*dbdata = state;
>+
>+#if DLZ_BIND9_USE_SINGLETON
> 	dlz_bind9_state = state;
> 	dlz_bind9_state_ref_count++;
>+#endif
> 
> 	return ISC_R_SUCCESS;
> 
>@@ -731,14 +750,18 @@ _PUBLIC_ isc_result_t dlz_create(const char *dlzname,
> _PUBLIC_ void dlz_destroy(void *dbdata)
> {
> 	struct dlz_bind9_data *state = talloc_get_type_abort(dbdata, struct dlz_bind9_data);
>-	state->log(ISC_LOG_INFO, "samba_dlz: shutting down");
> 
>+#if DLZ_BIND9_USE_SINGLETON
> 	dlz_bind9_state_ref_count--;
> 	if (dlz_bind9_state_ref_count == 0) {
>-		talloc_unlink(state, state->samdb);
>-		talloc_free(state);
> 		dlz_bind9_state = NULL;
>+	} else {
>+		return;
> 	}
>+#endif
>+	
>+	state->log(ISC_LOG_INFO, "samba_dlz: shutting down instance %p", state);
>+	talloc_free(state);
> }
> 
>

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Attachments on bug 13214: 16596