Attachment 14670 Details for Bug 13600 – possible patch for 4.5

[patch] possible patch for 4.5

v-early-cname-loop.patch (text/plain), 13.84 KB, created by Andrew Bartlett on 2018-11-21 04:57:13 UTC

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Creator: Andrew Bartlett

Created: 2018-11-21 04:57:13 UTC

Size: 13.84 KB

patch

obsolete

>From 92c84d9594b4306a5808c1df4166cef8bd5ae7a9 Mon Sep 17 00:00:00 2001
>From: Volker Lendecke <vl@samba.org>
>Date: Fri, 12 Aug 2016 16:40:05 +0200
>Subject: [PATCH 1/4] libreplace: Ask for eventfd(2)
>
>This will be used in tevent soon
>
>Signed-off-by: Volker Lendecke <vl@samba.org>
>Reviewed-by: Stefan Metzmacher <metze@samba.org>
>Reviewed-by: Jeremy Allison <jra@samba.org>
>(cherry picked from commit 4771d0792e4343cc8631a36247a2f3c7c31d58b3)
>---
> lib/replace/wscript | 3 +++
> 1 file changed, 3 insertions(+)
>
>diff --git a/lib/replace/wscript b/lib/replace/wscript
>index 145300d235c..1dfd90293ea 100644
>--- a/lib/replace/wscript
>+++ b/lib/replace/wscript
>@@ -483,6 +483,9 @@ removeea setea
>     if conf.CONFIG_SET('HAVE_PORT_CREATE') and conf.CONFIG_SET('HAVE_PORT_H'):
>         conf.DEFINE('HAVE_SOLARIS_PORTS', 1)
> 
>+    if conf.CHECK_FUNCS('eventfd', headers='sys/eventfd.h'):
>+        conf.DEFINE('HAVE_EVENTFD', 1)
>+
>     conf.CHECK_HEADERS('poll.h')
>     conf.CHECK_FUNCS('poll')
> 
>-- 
>2.11.0
>
>
>From 288fdc54121988105e28adeb35ef2bb6daa509f6 Mon Sep 17 00:00:00 2001
>From: Volker Lendecke <vl@samba.org>
>Date: Mon, 15 Aug 2016 10:33:09 +0200
>Subject: [PATCH 2/4] tevent: Fix a typo
>
>Signed-off-by: Volker Lendecke <vl@samba.org>
>Reviewed-by: Stefan Metzmacher <metze@samba.org>
>Reviewed-by: Jeremy Allison <jra@samba.org>
>(cherry picked from commit c4ef0c8f3ecc4266fed3af8537ba2998730b3750)
>---
> lib/tevent/tevent_threads.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/lib/tevent/tevent_threads.c b/lib/tevent/tevent_threads.c
>index 15882e4f40b..22b854c410f 100644
>--- a/lib/tevent/tevent_threads.c
>+++ b/lib/tevent/tevent_threads.c
>@@ -108,7 +108,7 @@ static void schedule_immediate_functions(struct tevent_thread_proxy *tp)
> 	if (tp->tofree_im_list != NULL) {
> 		/*
> 		 * Once the current immediate events
>-		 * are processed, we need to reshedule
>+		 * are processed, we need to reschedule
> 		 * ourselves to free them. This works
> 		 * as tevent_schedule_immediate()
> 		 * always adds events to the *END* of
>-- 
>2.11.0
>
>
>From 2988c42c7fb06dea5d952ec50be5e767b0e9efc0 Mon Sep 17 00:00:00 2001
>From: Volker Lendecke <vl@samba.org>
>Date: Fri, 29 Jul 2016 08:53:59 +0200
>Subject: [PATCH 3/4] tevent: Move the async wakeup pipe to common
>
>Signalling the main event loop will also happen from threads soon, and
>that will use the same mechanism. This also keeps the pipe open after the last
>signal handler is removed. Threaded jobs will come and go very frequently, and
>always setting up and tearing down the pipe for each job will be expensive.
>Also, this is "just" two file descriptors, and with eventfd just one.
>
>Signed-off-by: Volker Lendecke <vl@samba.org>
>Reviewed-by: Stefan Metzmacher <metze@samba.org>
>Reviewed-by: Jeremy Allison <jra@samba.org>
>(cherry picked from commit 8a9b8ac72461657a3a5de2fd5232eaa9861bf696)
>---
> lib/tevent/ABI/tevent-0.9.29.sigs |  3 ++
> lib/tevent/tevent.c               | 87 +++++++++++++++++++++++++++++++++++++--
> lib/tevent/tevent_internal.h      |  4 ++
> lib/tevent/tevent_poll.c          |  5 +--
> lib/tevent/tevent_signal.c        | 60 ++++-----------------------
> 5 files changed, 99 insertions(+), 60 deletions(-)
>
>diff --git a/lib/tevent/ABI/tevent-0.9.29.sigs b/lib/tevent/ABI/tevent-0.9.29.sigs
>index 135775171ea..4b647419d08 100644
>--- a/lib/tevent/ABI/tevent-0.9.29.sigs
>+++ b/lib/tevent/ABI/tevent-0.9.29.sigs
>@@ -28,10 +28,13 @@ tevent_common_fd_destructor: int (struct tevent_fd *)
> tevent_common_fd_get_flags: uint16_t (struct tevent_fd *)
> tevent_common_fd_set_close_fn: void (struct tevent_fd *, tevent_fd_close_fn_t)
> tevent_common_fd_set_flags: void (struct tevent_fd *, uint16_t)
>+tevent_common_have_events: bool (struct tevent_context *)
> tevent_common_loop_immediate: bool (struct tevent_context *)
> tevent_common_loop_timer_delay: struct timeval (struct tevent_context *)
> tevent_common_loop_wait: int (struct tevent_context *, const char *)
> tevent_common_schedule_immediate: void (struct tevent_immediate *, struct tevent_context *, tevent_immediate_handler_t, void *, const char *, const char *)
>+tevent_common_wakeup: int (struct tevent_context *)
>+tevent_common_wakeup_init: int (struct tevent_context *)
> tevent_context_init: struct tevent_context *(TALLOC_CTX *)
> tevent_context_init_byname: struct tevent_context *(TALLOC_CTX *, const char *)
> tevent_context_init_ops: struct tevent_context *(TALLOC_CTX *, const struct tevent_ops *, void *)
>diff --git a/lib/tevent/tevent.c b/lib/tevent/tevent.c
>index 843cf0560f3..34cd402d5e4 100644
>--- a/lib/tevent/tevent.c
>+++ b/lib/tevent/tevent.c
>@@ -620,6 +620,28 @@ done:
> 	return ret;
> }
> 
>+bool tevent_common_have_events(struct tevent_context *ev)
>+{
>+	if (ev->fd_events != NULL) {
>+		if (ev->fd_events != ev->pipe_fde) {
>+			return true;
>+		}
>+		if (ev->fd_events->next != NULL) {
>+			return true;
>+		}
>+
>+		/*
>+		 * At this point we just have the wakeup pipe event as
>+		 * the only fd_event. That one does not count as a
>+		 * regular event, so look at the other event types.
>+		 */
>+	}
>+
>+	return ((ev->timer_events != NULL) ||
>+		(ev->immediate_events != NULL) ||
>+		(ev->signal_events != NULL));
>+}
>+
> /*
>   return on failure or (with 0) if all fd events are removed
> */
>@@ -629,10 +651,7 @@ int tevent_common_loop_wait(struct tevent_context *ev,
> 	/*
> 	 * loop as long as we have events pending
> 	 */
>-	while (ev->fd_events ||
>-	       ev->timer_events ||
>-	       ev->immediate_events ||
>-	       ev->signal_events) {
>+	while (tevent_common_have_events(ev)) {
> 		int ret;
> 		ret = _tevent_loop_once(ev, location);
> 		if (ret != 0) {
>@@ -670,3 +689,63 @@ int tevent_re_initialise(struct tevent_context *ev)
> 
> 	return ev->ops->context_init(ev);
> }
>+
>+static void wakeup_pipe_handler(struct tevent_context *ev,
>+				struct tevent_fd *fde,
>+				uint16_t flags, void *_private)
>+{
>+	ssize_t ret;
>+
>+	char c[16];
>+	/* its non-blocking, doesn't matter if we read too much */
>+	do {
>+		ret = read(fde->fd, c, sizeof(c));
>+	} while (ret == -1 && errno == EINTR);
>+}
>+
>+/*
>+ * Initialize the wakeup pipe and pipe fde
>+ */
>+
>+int tevent_common_wakeup_init(struct tevent_context *ev)
>+{
>+	int ret;
>+
>+	if (ev->pipe_fde != NULL) {
>+		return 0;
>+	}
>+
>+	ret = pipe(ev->pipe_fds);
>+	if (ret == -1) {
>+		return errno;
>+	}
>+	ev_set_blocking(ev->pipe_fds[0], false);
>+	ev_set_blocking(ev->pipe_fds[1], false);
>+
>+	ev->pipe_fde = tevent_add_fd(ev, ev, ev->pipe_fds[0],
>+				     TEVENT_FD_READ,
>+				     wakeup_pipe_handler, NULL);
>+	if (ev->pipe_fde == NULL) {
>+		close(ev->pipe_fds[0]);
>+		close(ev->pipe_fds[1]);
>+		return ENOMEM;
>+	}
>+
>+	return 0;
>+}
>+
>+int tevent_common_wakeup(struct tevent_context *ev)
>+{
>+	ssize_t ret;
>+
>+	if (ev->pipe_fds[1] == -1) {
>+		return ENOTCONN;
>+	}
>+
>+	do {
>+		char c = '\0';
>+		ret = write(ev->pipe_fds[1], &c, 1);
>+	} while ((ret == -1) && (errno == EINTR));
>+
>+	return 0;
>+}
>diff --git a/lib/tevent/tevent_internal.h b/lib/tevent/tevent_internal.h
>index 10cc4a47f83..83627705095 100644
>--- a/lib/tevent/tevent_internal.h
>+++ b/lib/tevent/tevent_internal.h
>@@ -328,6 +328,10 @@ void tevent_common_schedule_immediate(struct tevent_immediate *im,
> 				      const char *location);
> bool tevent_common_loop_immediate(struct tevent_context *ev);
> 
>+bool tevent_common_have_events(struct tevent_context *ev);
>+int tevent_common_wakeup_init(struct tevent_context *ev);
>+int tevent_common_wakeup(struct tevent_context *ev);
>+
> struct tevent_signal *tevent_common_add_signal(struct tevent_context *ev,
> 					       TALLOC_CTX *mem_ctx,
> 					       int signum,
>diff --git a/lib/tevent/tevent_poll.c b/lib/tevent/tevent_poll.c
>index e1c305d20ea..3547e912b2c 100644
>--- a/lib/tevent/tevent_poll.c
>+++ b/lib/tevent/tevent_poll.c
>@@ -667,10 +667,7 @@ static int poll_event_loop_wait(struct tevent_context *ev,
> 	/*
> 	 * loop as long as we have events pending
> 	 */
>-	while (ev->fd_events ||
>-	       ev->timer_events ||
>-	       ev->immediate_events ||
>-	       ev->signal_events ||
>+	while (tevent_common_have_events(ev) ||
> 	       poll_ev->fresh ||
> 	       poll_ev->disabled) {
> 		int ret;
>diff --git a/lib/tevent/tevent_signal.c b/lib/tevent/tevent_signal.c
>index 635a7a177aa..c85e1c528c4 100644
>--- a/lib/tevent/tevent_signal.c
>+++ b/lib/tevent/tevent_signal.c
>@@ -95,7 +95,6 @@ static uint32_t tevent_sig_count(struct tevent_sigcounter s)
> */
> static void tevent_common_signal_handler(int signum)
> {
>-	char c = 0;
> 	struct tevent_common_signal_list *sl;
> 	struct tevent_context *ev = NULL;
> 	int saved_errno = errno;
>@@ -106,13 +105,8 @@ static void tevent_common_signal_handler(int signum)
> 	/* Write to each unique event context. */
> 	for (sl = sig_state->sig_handlers[signum]; sl; sl = sl->next) {
> 		if (sl->se->event_ctx && sl->se->event_ctx != ev) {
>-			ssize_t ret;
>-
> 			ev = sl->se->event_ctx;
>-			/* doesn't matter if this pipe overflows */
>-			do {
>-				ret = write(ev->pipe_fds[1], &c, 1);
>-			} while (ret == -1 && errno == EINTR);
>+			tevent_common_wakeup(ev);
> 		}
> 	}
> 
>@@ -198,16 +192,6 @@ static int tevent_signal_destructor(struct tevent_signal *se)
> 		struct tevent_context *ev = se->event_ctx;
> 
> 		DLIST_REMOVE(ev->signal_events, se);
>-
>-		if (ev->signal_events == NULL && ev->pipe_fde != NULL) {
>-			/*
>-			 * This was the last signal. Destroy the pipe.
>-			 */
>-			TALLOC_FREE(ev->pipe_fde);
>-
>-			close(ev->pipe_fds[0]);
>-			close(ev->pipe_fds[1]);
>-		}
> 	}
> 
> 	talloc_free(sl);
>@@ -233,21 +217,6 @@ static int tevent_signal_destructor(struct tevent_signal *se)
> }
> 
> /*
>-  this is part of the pipe hack needed to avoid the signal race condition
>-*/
>-static void signal_pipe_handler(struct tevent_context *ev, struct tevent_fd *fde, 
>-				uint16_t flags, void *_private)
>-{
>-	ssize_t ret;
>-
>-	char c[16];
>-	/* its non-blocking, doesn't matter if we read too much */
>-	do {
>-		ret = read(fde->fd, c, sizeof(c));
>-	} while (ret == -1 && errno == EINTR);
>-}
>-
>-/*
>   add a signal event
>   return NULL on failure (memory allocation error)
> */
>@@ -263,6 +232,13 @@ struct tevent_signal *tevent_common_add_signal(struct tevent_context *ev,
> 	struct tevent_signal *se;
> 	struct tevent_common_signal_list *sl;
> 	sigset_t set, oldset;
>+	int ret;
>+
>+	ret = tevent_common_wakeup_init(ev);
>+	if (ret != 0) {
>+		errno = ret;
>+		return NULL;
>+	}
> 
> 	if (signum >= TEVENT_NUM_SIGNALS) {
> 		errno = EINVAL;
>@@ -304,26 +280,6 @@ struct tevent_signal *tevent_common_add_signal(struct tevent_context *ev,
> 		return NULL;
> 	}
> 
>-	/* we need to setup the pipe hack handler if not already
>-	   setup */
>-	if (ev->pipe_fde == NULL) {
>-		if (pipe(ev->pipe_fds) == -1) {
>-			talloc_free(se);
>-			return NULL;
>-		}
>-		ev_set_blocking(ev->pipe_fds[0], false);
>-		ev_set_blocking(ev->pipe_fds[1], false);
>-		ev->pipe_fde = tevent_add_fd(ev, ev, ev->pipe_fds[0],
>-					     TEVENT_FD_READ,
>-					     signal_pipe_handler, NULL);
>-		if (!ev->pipe_fde) {
>-			close(ev->pipe_fds[0]);
>-			close(ev->pipe_fds[1]);
>-			talloc_free(se);
>-			return NULL;
>-		}
>-	}
>-
> 	/* only install a signal handler if not already installed */
> 	if (sig_state->sig_handlers[signum] == NULL) {
> 		struct sigaction act;
>-- 
>2.11.0
>
>
>diff --git a/python/samba/tests/dns.py b/python/samba/tests/dns.py
>index 43eccddd957..9d040acdea4 100644
>--- a/python/samba/tests/dns.py
>+++ b/python/samba/tests/dns.py
>@@ -937,6 +937,29 @@ class TestComplexQueries(DNSTest):
>         self.assertEquals(response.answers[1].name, name2)
>         self.assertEquals(response.answers[1].rdata, name0)
> 
>+    def test_cname_loop(self):
>+        cname1 = "cnamelooptestrec." + self.get_dns_domain()
>+        cname2 = "cnamelooptestrec2." + self.get_dns_domain()
>+        cname3 = "cnamelooptestrec3." + self.get_dns_domain()
>+        self.make_dns_update(cname1, cname2, dnsp.DNS_TYPE_CNAME)
>+        self.make_dns_update(cname2, cname3, dnsp.DNS_TYPE_CNAME)
>+        self.make_dns_update(cname3, cname1, dnsp.DNS_TYPE_CNAME)
>+
>+        p = self.make_name_packet(dns.DNS_OPCODE_QUERY)
>+        questions = []
>+
>+        q = self.make_name_question(cname1,
>+                                    dns.DNS_QTYPE_A,
>+                                    dns.DNS_QCLASS_IN)
>+        questions.append(q)
>+        self.finish_name_packet(p, questions)
>+
>+        response = self.dns_transaction_udp(p)
>+
>+        max_recursion_depth = 20
>+        self.assertEquals(len(response.answers), max_recursion_depth)
>+
>+
> class TestInvalidQueries(DNSTest):
> 
>     def test_one_a_query(self):
>diff --git a/selftest/knownfail.d/dns b/selftest/knownfail.d/dns
>index 6553c1fffe0..a22bcce6bf4 100644
>--- a/selftest/knownfail.d/dns
>+++ b/selftest/knownfail.d/dns
>@@ -45,6 +45,11 @@ samba.tests.dns.__main__.TestSimpleQueries.test_one_SOA_query\(rodc:local\)
> samba.tests.dns.__main__.TestSimpleQueries.test_one_SOA_query\(vampire_dc:local\)
> samba.tests.dns.__main__.TestSimpleQueries.test_one_a_query\(vampire_dc:local\)
> samba.tests.dns.__main__.TestSimpleQueries.test_one_a_query_tcp\(vampire_dc:local\)
>+#
>+# rodc and vampire_dc require signed dns updates, so the test setup
>+# fails, but the test does run on fl2003dc
>+^samba.tests.dns.__main__.TestComplexQueries.test_cname_loop\(rodc:local\)
>+^samba.tests.dns.__main__.TestComplexQueries.test_cname_loop\(vampire_dc:local\)
> samba.tests.dns.__main__.TestSimpleQueries.test_one_mx_query\(vampire_dc:local\)
> samba.tests.dns.__main__.TestSimpleQueries.test_qtype_all_query\(vampire_dc:local\)
> samba.tests.dns.__main__.TestSimpleQueries.test_soa_hostname_query\(vampire_dc:local\)
>diff --git a/source4/dns_server/dns_query.c b/source4/dns_server/dns_query.c
>index b8ecc2e7ac7..89199e16787 100644
>--- a/source4/dns_server/dns_query.c
>+++ b/source4/dns_server/dns_query.c
>@@ -40,6 +40,7 @@
> 
> #undef DBGC_CLASS
> #define DBGC_CLASS DBGC_DNS
>+#define MAX_Q_RECURSION_DEPTH 20
> 
> struct forwarder_string {
> 	const char *forwarder;
>@@ -470,6 +471,11 @@ static struct tevent_req *handle_dnsrpcrec_send(
> 	state->answers = answers;
> 	state->nsrecs = nsrecs;
> 
>+	if (talloc_array_length(*answers) >= MAX_Q_RECURSION_DEPTH) {
>+		tevent_req_done(req);
>+		return tevent_req_post(req, ev);
>+	}
>+
> 	resolve_cname = ((rec->wType == DNS_TYPE_CNAME) &&
> 			 ((question->question_type == DNS_QTYPE_A) ||
> 			  (question->question_type == DNS_QTYPE_AAAA)));

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