Fix detection of O_NONBLOCK inheritance.

The original test failed occasionally on a busy
FreeBSD server when accept() returned EAGAIN.

Backport of r1449568 from trunk resp. r1449569
from 1.5.x resp. r1449570 from 1.4.x resp.
r1449571 from 1.3.x.


git-svn-id: http://svn.apache.org/repos/asf/apr/apr/branches/0.9.x@1449572 13f79535-47bb-0310-9956-ffa450edef68

2 files changed, 36 insertions, 1 deletions

diff --git a/CHANGES b/CHANGES
index 11ac2fce9..729b0e9ca 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,10 @@
-                                                     -*- coding: utf-8 -*-
+                                                     
+-*- coding: utf-8 -*-
 Changes with APR 0.9.21
 
+  *) configure: Fix detection of O_NONBLOCK inheritance on busy
+     systems.  [Rainer Jung]
+
   *) apr_time_exp_*() on Windows: Fix error in the tm_yday field of
      apr_time_exp_t for times within leap years.  PR 53175.
      [Jeff Trawick]
diff --git a/build/apr_network.m4 b/build/apr_network.m4
index 16eb92b8c..e01f0b1ac 100644
--- a/build/apr_network.m4
+++ b/build/apr_network.m4
@@ -354,13 +354,24 @@ dnl
 AC_DEFUN(APR_CHECK_O_NONBLOCK_INHERITED,[
   AC_CACHE_CHECK(if O_NONBLOCK setting is inherited from listening sockets, ac_cv_o_nonblock_inherited,[
   AC_TRY_RUN( [
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
+#ifdef HAVE_STDIO_H
 #include <stdio.h>
+#endif
 #ifdef HAVE_SYS_TYPES_H
 #include <sys/types.h>
 #endif
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
 #endif
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
 #ifdef HAVE_NETINET_IN_H
 #include <netinet/in.h>
 #endif
@@ -431,6 +442,26 @@ int main(void) {
         exit(1);
     }
     sa_len = sizeof sa;
+    /* 1 second select timeout */
+    tv.tv_sec = 1;
+    tv.tv_usec = 0;
+    /* Set up fd set */
+    FD_ZERO(&fds);
+    FD_SET(listen_s, &fds);
+    /* Wait for socket to become readable */
+    rc = select(listen_s + 1, &fds, NULL, NULL, &tv);
+    if (rc < 0) {
+        perror("select");
+        exit(1);
+    }
+    if (rc == 0) {
+        fprintf(stderr, "Socket failed to become readable (timeout)\n");
+        exit(1);
+    }
+    if (!FD_ISSET(listen_s, &fds)) {
+        fprintf(stderr, "Socket failed to become readable (selected another fd)\n");
+        exit(1);
+    }
     connected_s = accept(listen_s, (struct sockaddr *)&sa, &sa_len);
     if (connected_s < 0) {
         perror("accept");