Use a more sophisticated configure check for epoll.

This is from the GNU Autoconf archive.

http://www.gnu.org/software/autoconf-archive/ax_have_epoll.html

http://seclists.org/nmap-dev/2012/q3/598
http://seclists.org/nmap-dev/2012/q3/657

nsock/src/acinclude.m4

@@ -0,0 +1,104 @@
+# ===========================================================================
+#       http://www.gnu.org/software/autoconf-archive/ax_have_epoll.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_HAVE_EPOLL([ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
+#   AX_HAVE_EPOLL_PWAIT([ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
+#
+# DESCRIPTION
+#
+#   This macro determines whether the system supports the epoll I/O event
+#   interface. A neat usage example would be:
+#
+#     AX_HAVE_EPOLL(
+#       [AX_CONFIG_FEATURE_ENABLE(epoll)],
+#       [AX_CONFIG_FEATURE_DISABLE(epoll)])
+#     AX_CONFIG_FEATURE(
+#       [epoll], [This platform supports epoll(7)],
+#       [HAVE_EPOLL], [This platform supports epoll(7).])
+#
+#   The epoll interface was added to the Linux kernel in version 2.5.45, and
+#   the macro verifies that a kernel newer than this is installed. This
+#   check is somewhat unreliable if <linux/version.h> doesn't match the
+#   running kernel, but it is necessary regardless, because glibc comes with
+#   stubs for the epoll_create(), epoll_wait(), etc. that allow programs to
+#   compile and link even if the kernel is too old; the problem would then
+#   be detected only at runtime.
+#
+#   Linux kernel version 2.6.19 adds the epoll_pwait() call in addition to
+#   epoll_wait(). The availability of that function can be tested with the
+#   second macro. Generally speaking, it is safe to assume that
+#   AX_HAVE_EPOLL would succeed if AX_HAVE_EPOLL_PWAIT has, but not the
+#   other way round.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Peter Simons <simons@cryp.to>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 10
+
+AC_DEFUN([AX_HAVE_EPOLL], [dnl
+  ax_have_epoll_cppflags="${CPPFLAGS}"
+  AC_CHECK_HEADER([linux/version.h], [CPPFLAGS="${CPPFLAGS} -DHAVE_LINUX_VERSION_H"])
+  AC_MSG_CHECKING([for Linux epoll(7) interface])
+  AC_CACHE_VAL([ax_cv_have_epoll], [dnl
+    AC_LINK_IFELSE([dnl
+      AC_LANG_PROGRAM([dnl
+#include <sys/epoll.h>
+#ifdef HAVE_LINUX_VERSION_H
+#  include <linux/version.h>
+#  if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,45)
+#    error linux kernel version is too old to have epoll
+#  endif
+#endif
+], [dnl
+int fd, rc;
+struct epoll_event ev;
+fd = epoll_create(128);
+rc = epoll_wait(fd, &ev, 1, 0);])],
+      [ax_cv_have_epoll=yes],
+      [ax_cv_have_epoll=no])])
+  CPPFLAGS="${ax_have_epoll_cppflags}"
+  AS_IF([test "${ax_cv_have_epoll}" = "yes"],
+    [AC_MSG_RESULT([yes])
+$1],[AC_MSG_RESULT([no])
+$2])
+])dnl
+
+AC_DEFUN([AX_HAVE_EPOLL_PWAIT], [dnl
+  ax_have_epoll_cppflags="${CPPFLAGS}"
+  AC_CHECK_HEADER([linux/version.h],
+    [CPPFLAGS="${CPPFLAGS} -DHAVE_LINUX_VERSION_H"])
+  AC_MSG_CHECKING([for Linux epoll(7) interface with signals extension])
+  AC_CACHE_VAL([ax_cv_have_epoll_pwait], [dnl
+    AC_LINK_IFELSE([dnl
+      AC_LANG_PROGRAM([dnl
+#ifdef HAVE_LINUX_VERSION_H
+#  include <linux/version.h>
+#  if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
+#    error linux kernel version is too old to have epoll_pwait
+#  endif
+#endif
+#include <sys/epoll.h>
+#include <signal.h>
+], [dnl
+int fd, rc;
+struct epoll_event ev;
+fd = epoll_create(128);
+rc = epoll_wait(fd, &ev, 1, 0);
+rc = epoll_pwait(fd, &ev, 1, 0, (sigset_t const *)(0));])],
+      [ax_cv_have_epoll_pwait=yes],
+      [ax_cv_have_epoll_pwait=no])])
+  CPPFLAGS="${ax_have_epoll_cppflags}"
+  AS_IF([test "${ax_cv_have_epoll_pwait}" = "yes"],
+    [AC_MSG_RESULT([yes])
+$1],[AC_MSG_RESULT([no])
+$2])
+])dnl

nsock/src/aclocal.m4

@@ -10,118 +10,108 @@ dnl but WITHOUT ANY WARRANTY, to the extent permitted by law; without
 dnl even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 dnl PARTICULAR PURPOSE.
 
-# Do all the work for Automake.  This macro actually does too much --
+# ===========================================================================
-# some checks are only needed if your package does certain things.
+#       http://www.gnu.org/software/autoconf-archive/ax_have_epoll.html
-# But this isn't really a big deal.
+# ===========================================================================
-
-# serial 1
-
-dnl Usage:
-dnl AM_INIT_AUTOMAKE(package,version, [no-define])
-
-AC_DEFUN(AM_INIT_AUTOMAKE,
-[AC_REQUIRE([AC_PROG_INSTALL])
-PACKAGE=[$1]
-AC_SUBST(PACKAGE)
-VERSION=[$2]
-AC_SUBST(VERSION)
-dnl test to see if srcdir already configured
-if test "`cd $srcdir && pwd`" != "`pwd`" && test -f $srcdir/config.status; then
-  AC_MSG_ERROR([source directory already configured; run "make distclean" there first])
-fi
-ifelse([$3],,
-AC_DEFINE_UNQUOTED(PACKAGE, "$PACKAGE", [Name of package])
-AC_DEFINE_UNQUOTED(VERSION, "$VERSION", [Version number of package]))
-AC_REQUIRE([AM_SANITY_CHECK])
-AC_REQUIRE([AC_ARG_PROGRAM])
-dnl FIXME This is truly gross.
-missing_dir=`cd $ac_aux_dir && pwd`
-AM_MISSING_PROG(ACLOCAL, aclocal, $missing_dir)
-AM_MISSING_PROG(AUTOCONF, autoconf, $missing_dir)
-AM_MISSING_PROG(AUTOMAKE, automake, $missing_dir)
-AM_MISSING_PROG(AUTOHEADER, autoheader, $missing_dir)
-AM_MISSING_PROG(MAKEINFO, makeinfo, $missing_dir)
-AC_REQUIRE([AC_PROG_MAKE_SET])])
-
 #
-# Check to make sure that the build environment is sane.
+# SYNOPSIS
 #
+#   AX_HAVE_EPOLL([ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
+#   AX_HAVE_EPOLL_PWAIT([ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
+#
+# DESCRIPTION
+#
+#   This macro determines whether the system supports the epoll I/O event
+#   interface. A neat usage example would be:
+#
+#     AX_HAVE_EPOLL(
+#       [AX_CONFIG_FEATURE_ENABLE(epoll)],
+#       [AX_CONFIG_FEATURE_DISABLE(epoll)])
+#     AX_CONFIG_FEATURE(
+#       [epoll], [This platform supports epoll(7)],
+#       [HAVE_EPOLL], [This platform supports epoll(7).])
+#
+#   The epoll interface was added to the Linux kernel in version 2.5.45, and
+#   the macro verifies that a kernel newer than this is installed. This
+#   check is somewhat unreliable if <linux/version.h> doesn't match the
+#   running kernel, but it is necessary regardless, because glibc comes with
+#   stubs for the epoll_create(), epoll_wait(), etc. that allow programs to
+#   compile and link even if the kernel is too old; the problem would then
+#   be detected only at runtime.
+#
+#   Linux kernel version 2.6.19 adds the epoll_pwait() call in addition to
+#   epoll_wait(). The availability of that function can be tested with the
+#   second macro. Generally speaking, it is safe to assume that
+#   AX_HAVE_EPOLL would succeed if AX_HAVE_EPOLL_PWAIT has, but not the
+#   other way round.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Peter Simons <simons@cryp.to>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
 
-AC_DEFUN(AM_SANITY_CHECK,
+#serial 10
-[AC_MSG_CHECKING([whether build environment is sane])
-# Just in case
-sleep 1
-echo timestamp > conftestfile
-# Do `set' in a subshell so we don't clobber the current shell's
-# arguments.  Must try -L first in case configure is actually a
-# symlink; some systems play weird games with the mod time of symlinks
-# (eg FreeBSD returns the mod time of the symlink's containing
-# directory).
-if (
-   set X `ls -Lt $srcdir/configure conftestfile 2> /dev/null`
-   if test "[$]*" = "X"; then
-      # -L didn't work.
-      set X `ls -t $srcdir/configure conftestfile`
-   fi
-   if test "[$]*" != "X $srcdir/configure conftestfile" \
-      && test "[$]*" != "X conftestfile $srcdir/configure"; then
 
-      # If neither matched, then we have a broken ls.  This can happen
+AC_DEFUN([AX_HAVE_EPOLL], [dnl
-      # if, for instance, CONFIG_SHELL is bash and it inherits a
+  ax_have_epoll_cppflags="${CPPFLAGS}"
-      # broken ls alias from the environment.  This has actually
+  AC_CHECK_HEADER([linux/version.h], [CPPFLAGS="${CPPFLAGS} -DHAVE_LINUX_VERSION_H"])
-      # happened.  Such a system could not be considered "sane".
+  AC_MSG_CHECKING([for Linux epoll(7) interface])
-      AC_MSG_ERROR([ls -t appears to fail.  Make sure there is not a broken
+  AC_CACHE_VAL([ax_cv_have_epoll], [dnl
-alias in your environment])
+    AC_LINK_IFELSE([dnl
-   fi
+      AC_LANG_PROGRAM([dnl
+#include <sys/epoll.h>
+#ifdef HAVE_LINUX_VERSION_H
+#  include <linux/version.h>
+#  if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,45)
+#    error linux kernel version is too old to have epoll
+#  endif
+#endif
+], [dnl
+int fd, rc;
+struct epoll_event ev;
+fd = epoll_create(128);
+rc = epoll_wait(fd, &ev, 1, 0);])],
+      [ax_cv_have_epoll=yes],
+      [ax_cv_have_epoll=no])])
+  CPPFLAGS="${ax_have_epoll_cppflags}"
+  AS_IF([test "${ax_cv_have_epoll}" = "yes"],
+    [AC_MSG_RESULT([yes])
+$1],[AC_MSG_RESULT([no])
+$2])
+])dnl
 
-   test "[$]2" = conftestfile
+AC_DEFUN([AX_HAVE_EPOLL_PWAIT], [dnl
-   )
+  ax_have_epoll_cppflags="${CPPFLAGS}"
-then
+  AC_CHECK_HEADER([linux/version.h],
-   # Ok.
+    [CPPFLAGS="${CPPFLAGS} -DHAVE_LINUX_VERSION_H"])
-   :
+  AC_MSG_CHECKING([for Linux epoll(7) interface with signals extension])
-else
+  AC_CACHE_VAL([ax_cv_have_epoll_pwait], [dnl
-   AC_MSG_ERROR([newly created file is older than distributed files!
+    AC_LINK_IFELSE([dnl
-Check your system clock])
+      AC_LANG_PROGRAM([dnl
-fi
+#ifdef HAVE_LINUX_VERSION_H
-rm -f conftest*
+#  include <linux/version.h>
-AC_MSG_RESULT(yes)])
+#  if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
-
+#    error linux kernel version is too old to have epoll_pwait
-dnl AM_MISSING_PROG(NAME, PROGRAM, DIRECTORY)
+#  endif
-dnl The program must properly implement --version.
+#endif
-AC_DEFUN(AM_MISSING_PROG,
+#include <sys/epoll.h>
-[AC_MSG_CHECKING(for working $2)
+#include <signal.h>
-# Run test in a subshell; some versions of sh will print an error if
+], [dnl
-# an executable is not found, even if stderr is redirected.
+int fd, rc;
-# Redirect stdin to placate older versions of autoconf.  Sigh.
+struct epoll_event ev;
-if ($2 --version) < /dev/null > /dev/null 2>&1; then
+fd = epoll_create(128);
-   $1=$2
+rc = epoll_wait(fd, &ev, 1, 0);
-   AC_MSG_RESULT(found)
+rc = epoll_pwait(fd, &ev, 1, 0, (sigset_t const *)(0));])],
-else
+      [ax_cv_have_epoll_pwait=yes],
-   $1="$3/missing $2"
+      [ax_cv_have_epoll_pwait=no])])
-   AC_MSG_RESULT(missing)
+  CPPFLAGS="${ax_have_epoll_cppflags}"
-fi
+  AS_IF([test "${ax_cv_have_epoll_pwait}" = "yes"],
-AC_SUBST($1)])
+    [AC_MSG_RESULT([yes])
-
+$1],[AC_MSG_RESULT([no])
-AC_DEFUN(AC_C___ATTRIBUTE__, [
+$2])
-AC_MSG_CHECKING(for __attribute__)
+])dnl
-AC_CACHE_VAL(ac_cv___attribute__, [
-AC_TRY_COMPILE([
-#include <stdlib.h>
-],
-[
-static void foo(void) __attribute__ ((noreturn));
-
-static void
-foo(void)
-{
-  exit(1);
-}
-],
-ac_cv___attribute__=yes,
-ac_cv___attribute__=no)])
-if test "$ac_cv___attribute__" = "yes"; then
-  AC_DEFINE(HAVE___ATTRIBUTE__, 1, [define if your compiler has __attribute__])
-fi
-AC_MSG_RESULT($ac_cv___attribute__)
-])
 

nsock/src/configure.ac

@@ -112,7 +112,7 @@ if test "$pcap_enabled" != "no"; then
   AC_DEFINE(HAVE_PCAP)
 fi
 
-AC_CHECK_FUNCS(epoll_create epoll_ctl epoll_wait, [AC_DEFINE(HAVE_EPOLL)], )
+AX_HAVE_EPOLL([AC_DEFINE(HAVE_EPOLL)], )
 
 dnl Checks for programs.
 AC_PROG_CC