From 6d02111b3eda21e3e94caab2f645232216c1f59b Mon Sep 17 00:00:00 2001
From: Simon Liu <simohayha.bobo@gmail.com>
Date: Sat, 21 Jul 2012 14:33:33 +0800
Subject: Add linux accept4() support.

---
 configure.ac |  1 +
 memcached.c  | 41 ++++++++++++++++++++++++++++++++++-------
 2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/configure.ac b/configure.ac
index f2639d6..7f22f21 100644
--- a/configure.ac
+++ b/configure.ac
@@ -476,6 +476,7 @@ AC_CHECK_FUNCS(getpagesizes)
 AC_CHECK_FUNCS(memcntl)
 AC_CHECK_FUNCS(sigignore)
 AC_CHECK_FUNCS(clock_gettime)
+AC_CHECK_FUNCS([accept4], [AC_DEFINE(HAVE_ACCEPT4, 1, [Define to 1 if support accept4])])
 
 AC_DEFUN([AC_C_ALIGNMENT],
 [AC_CACHE_CHECK(for alignment, ac_cv_c_alignment,
diff --git a/memcached.c b/memcached.c
index 9ec1597..eba0742 100644
--- a/memcached.c
+++ b/memcached.c
@@ -3792,12 +3792,15 @@ static enum transmit_result transmit(conn *c) {
 
 static void drive_machine(conn *c) {
     bool stop = false;
-    int sfd, flags = 1;
+    int sfd;
     socklen_t addrlen;
     struct sockaddr_storage addr;
     int nreqs = settings.reqs_per_event;
     int res;
     const char *str;
+#if (HAVE_ACCEPT4)
+    static int  use_accept4 = 1;
+#endif
 
     assert(c != NULL);
 
@@ -3806,7 +3809,26 @@ static void drive_machine(conn *c) {
         switch(c->state) {
         case conn_listening:
             addrlen = sizeof(addr);
-            if ((sfd = accept(c->sfd, (struct sockaddr *)&addr, &addrlen)) == -1) {
+#if (HAVE_ACCEPT4)
+            if (use_accept4) {
+                sfd = accept4(c->sfd, (struct sockaddr *)&addr, &addrlen, SOCK_NONBLOCK);
+            } else {
+                sfd = accept(c->sfd, (struct sockaddr *)&addr, &addrlen);
+            }
+#else
+            sfd = accept(c->sfd, (struct sockaddr *)&addr, &addrlen);
+#endif
+            if (sfd == -1) {
+#if (HAVE_ACCEPT4)
+
+                if (use_accept4 && errno == ENOSYS) {
+                    use_accept4 = 0;
+                    continue;
+                }
+                perror(use_accept4 ? "accept4()" : "accept()");
+#else
+                perror("accept()");
+#endif
                 if (errno == EAGAIN || errno == EWOULDBLOCK) {
                     /* these are transient, so don't log anything */
                     stop = true;
@@ -3821,12 +3843,17 @@ static void drive_machine(conn *c) {
                 }
                 break;
             }
-            if ((flags = fcntl(sfd, F_GETFL, 0)) < 0 ||
-                fcntl(sfd, F_SETFL, flags | O_NONBLOCK) < 0) {
-                perror("setting O_NONBLOCK");
-                close(sfd);
-                break;
+#if (HAVE_ACCEPT4)
+            if (!use_accept4) {
+#endif
+                if (fcntl(sfd, F_SETFL, fcntl(sfd, F_GETFL) | O_NONBLOCK) < 0) {
+                    perror("setting O_NONBLOCK");
+                    close(sfd);
+                    break;
+                }
+#if (HAVE_ACCEPT4)
             }
+#endif
 
             if (settings.maxconns_fast &&
                 stats.curr_conns + stats.reserved_fds >= settings.maxconns - 1) {
-- 
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