Merge r1789220, r1792675 from trunk: (6a466488) · Commits · CYBER - Cyber Security / TS 103 523 MSP / TLMSP / TLMSP Apache Httpd

CHANGES

+5 −0

Original line number	Diff line number	Diff line
		-- coding: utf-8 --
		Changes with Apache 2.4.28

		*) core: Disallow multiple Listen on the same IP:port when listener buckets
		are configured (ListenCoresBucketsRatio > 0), consistently with the single
		bucket case (default), thus avoiding the leak of the corresponding socket
		descriptors on graceful restart. [Yann Ylavic]

		*) event: Avoid listener periodic wake ups by using the pollset wake-ability
		when available. PR 57399. [Yann Ylavic, Luca Toscano]

STATUS

+0 −9

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		@@ -116,15 +116,6 @@ RELEASE SHOWSTOPPERS:
		PATCHES ACCEPTED TO BACKPORT FROM TRUNK:
		[ start all new proposals below, under PATCHES PROPOSED. ]

		*) core: Disallow multiple Listen on the same IP:port when listener buckets
		are configured (ListenCoresBucketsRatio > 0), consistently with the single
		bucket case (default), thus avoiding the leak of the corresponding socket
		descriptors on graceful restart.
		trunk patch: http://svn.apache.org/r1789220
		http://svn.apache.org/r1792675
		2.4.x patch: trunk works (modulo CHANGES)
		+1: ylavic, jim, jorton,

		*) prefork: This fixes race-condition in signals handling when httpd is
		runnning on foreground and user hits ctrl+c
		trunk patch: http://svn.apache.org/r1618555

docs/manual/mod/mpm_common.xml

+21 −0

Original line number	Diff line number	Diff line
		@@ -302,6 +302,27 @@ in *BSDs.</compatibility>
		<directive module="mpm_common">MaxSpareThreads</directive> lower bound values.
		The number of children processes needs to be a multiple of the number
		of buckets to optimally accept connections.</p>

		<note>
		<title>Multiple <directive>Listen</directive>ers or Apache HTTP servers on
		the same IP address and port</title>
		<p>Setting the <code>SO_REUSEPORT</code> option on the listening socket(s)
		consequently allows multiple processes (sharing the same <code>EUID</code>,
		e.g. <code>root</code>) to bind to the the same IP address and port,
		without the binding error raised by the system in the usual case.</p>
		<p>This also means that multiple instances of Apache httpd configured on a
		same <code>IP:port</code> and with a positive <directive>ListenCoresBucketsRatio</directive>
		would start without an error too, and then run with incoming connections
		evenly distributed accross both instances (this is NOT a recommendation or
		a sensible usage in any case, but just a notice that it would prevent such
		possible issues to be detected).</p>
		<p>Within the same instance, Apache httpd will check and fail to start if
		multiple <directive>Listen</directive> directives on the exact same IP (or
		hostname) and port are configured, thus avoiding the creation of some
		duplicated buckets which would be useless and kill performances. However
		it can't (and won't try harder to) catch all the possible overlapping cases
		(like a hostname resolving to an IP used elsewhere).</p>
		</note>
		</usage>
		</directivesynopsis>

server/listen.c

+33 −17

Original line number	Diff line number	Diff line
		@@ -277,18 +277,14 @@ static apr_status_t close_listeners_on_exec(void *v)
		return APR_SUCCESS;
		}

		static const char alloc_listener(process_rec process, char *addr,
		apr_port_t port, const char* proto,
		void *slave)
		static int find_listeners(ap_listen_rec from, ap_listen_rec to,
		const char *addr, apr_port_t port)
		{
		ap_listen_rec *walk, last;
		apr_status_t status;
		apr_sockaddr_t *sa;
		int found_listener = 0;
		int found = 0;

		while (*from) {
		apr_sockaddr_t sa = (from)->bind_addr;

		/* see if we've got an old listener for this address:port */
		for (walk = &old_listeners; *walk;) {
		sa = (*walk)->bind_addr;
		/* Some listeners are not real so they will not have a bind_addr. */
		if (sa) {
		ap_listen_rec *new;
		@@ -301,19 +297,39 @@ static const char alloc_listener(process_rec process, char *addr,
		if (port == oldport &&
		((!addr && !sa->hostname) \|\|
		((addr && sa->hostname) && !strcmp(sa->hostname, addr)))) {
		new = *walk;
		*walk = new->next;
		new->next = ap_listeners;
		ap_listeners = new;
		found_listener = 1;
		found = 1;
		if (!to) {
		break;
		}
		new = *from;
		*from = new->next;
		new->next = *to;
		*to = new;
		continue;
		}
		}

		walk = &(*walk)->next;
		from = &(*from)->next;
		}

		return found;
		}

		static const char alloc_listener(process_rec process, const char *addr,
		apr_port_t port, const char* proto,
		void *slave)
		{
		ap_listen_rec *last;
		apr_status_t status;
		apr_sockaddr_t *sa;

		/* see if we've got a listener for this address:port, which is an error */
		if (find_listeners(&ap_listeners, NULL, addr, port)) {
		return "Cannot define multiple Listeners on the same IP:port";
		}

		if (found_listener) {
		/* see if we've got an old listener for this address:port */
		if (find_listeners(&old_listeners, &ap_listeners, addr, port)) {
		if (ap_listeners->slave != slave) {
		return "Cannot define a slave on the same IP:port as a Listener";
		}