Add configure script

Some older installs don't have __kernel_rwf_t in linux/fs.h, so
add a check for that.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Makefile

@@ -14,10 +14,24 @@ all:
 	@$(MAKE) -C src
 	@$(MAKE) -C test
 
+config-host.mak: configure
+	@if [ ! -e "$@" ]; then					\
+	  echo "Running configure ...";				\
+	  ./configure;						\
+	else							\
+	  echo "$@ is out-of-date, running configure";		\
+	  sed -n "/.*Configured with/s/[^:]*: //p" "$@" | sh;	\
+	fi
+
+ifneq ($(MAKECMDGOALS),clean)
+include config-host.mak
+endif
+
 install:
 	@$(MAKE) -C src install prefix=$(DESTDIR)$(prefix) includedir=$(DESTDIR)$(includedir) libdir=$(DESTDIR)$(libdir)
 
 clean:
+	@rm -f config-host.mak config-host.h
 	@$(MAKE) -C src clean
 	@$(MAKE) -C test clean
 

configure

@@ -0,0 +1,127 @@
+#!/bin/sh
+#
+# set temporary file name
+if test ! -z "$TMPDIR" ; then
+    TMPDIR1="${TMPDIR}"
+elif test ! -z "$TEMPDIR" ; then
+    TMPDIR1="${TEMPDIR}"
+else
+    TMPDIR1="/tmp"
+fi
+
+cc=gcc
+
+TMPC="${TMPDIR1}/fio-conf-${RANDOM}-$$-${RANDOM}.c"
+TMPC2="${TMPDIR1}/fio-conf-${RANDOM}-$$-${RANDOM}-2.c"
+TMPO="${TMPDIR1}/fio-conf-${RANDOM}-$$-${RANDOM}.o"
+TMPE="${TMPDIR1}/fio-conf-${RANDOM}-$$-${RANDOM}.exe"
+
+# NB: do not call "exit" in the trap handler; this is buggy with some shells;
+# see <1285349658-3122-1-git-send-email-loic.minier@linaro.org>
+trap "rm -f $TMPC $TMPC2 $TMPO $TMPE" EXIT INT QUIT TERM
+
+rm -rf config.log
+
+config_host_mak="config-host.mak"
+config_host_h="config-host.h"
+
+rm -rf $config_host_mak
+rm -rf $config_host_h
+
+fatal() {
+  echo $@
+  echo "Configure failed, check config.log and/or the above output"
+  rm -rf $config_host_mak
+  rm -rf $config_host_h
+  exit 1
+}
+
+# Print result for each configuration test
+print_config() {
+  printf "%-30s%s\n" "$1" "$2"
+}
+
+# Default CFLAGS
+CFLAGS="-D_GNU_SOURCE -include config-host.h"
+BUILD_CFLAGS=""
+
+# Print configure header at the top of $config_host_h
+echo "/*" > $config_host_h
+echo " * Automatically generated by configure - do not modify" >> $config_host_h
+printf " * Configured with:" >> $config_host_h
+printf " * '%s'" "$0" "$@" >> $config_host_h
+echo "" >> $config_host_h
+echo " */" >> $config_host_h
+
+echo "# Automatically generated by configure - do not modify" > $config_host_mak
+printf "# Configured with:" >> $config_host_mak
+printf " '%s'" "$0" "$@" >> $config_host_mak
+echo >> $config_host_mak
+
+do_cc() {
+    # Run the compiler, capturing its output to the log.
+    echo $cc "$@" >> config.log
+    $cc "$@" >> config.log 2>&1 || return $?
+    # Test passed. If this is an --enable-werror build, rerun
+    # the test with -Werror and bail out if it fails. This
+    # makes warning-generating-errors in configure test code
+    # obvious to developers.
+    if test "$werror" != "yes"; then
+        return 0
+    fi
+    # Don't bother rerunning the compile if we were already using -Werror
+    case "$*" in
+        *-Werror*)
+           return 0
+        ;;
+    esac
+    echo $cc -Werror "$@" >> config.log
+    $cc -Werror "$@" >> config.log 2>&1 && return $?
+    echo "ERROR: configure test passed without -Werror but failed with -Werror."
+    echo "This is probably a bug in the configure script. The failing command"
+    echo "will be at the bottom of config.log."
+    fatal "You can run configure with --disable-werror to bypass this check."
+}
+
+compile_object() {
+  do_cc $CFLAGS -c -o $TMPO $TMPC
+}
+
+compile_prog() {
+  local_cflags="$1"
+  local_ldflags="$2 $LIBS"
+  echo "Compiling test case $3" >> config.log
+  do_cc $CFLAGS $local_cflags -o $TMPE $TMPC $LDFLAGS $local_ldflags
+}
+
+has() {
+  type "$1" >/dev/null 2>&1
+}
+
+output_sym() {
+  echo "$1=y" >> $config_host_mak
+  echo "#define $1" >> $config_host_h
+}
+
+##########################################
+# check for __kernel_rwf_t
+__kernel_rwf_t="no"
+cat > $TMPC << EOF
+#include <linux/fs.h>
+int main(int argc, char **argv)
+{
+  __kernel_rwf_t x;
+  x = 0;
+  return x;
+}
+EOF
+if compile_prog "" "" "__kernel_rwf_t"; then
+  __kernel_rwf_t="yes"
+fi
+print_config "__kernel_rwf_t" "$__kernel_rwf_t"
+
+#############################################################################
+
+if test "$__kernel_rwf_t" = "yes"; then
+  output_sym "CONFIG_HAVE_KERNEL_RWF_T"
+fi

src/compat.h

@@ -0,0 +1,8 @@
+#ifndef LIBURING_COMPAT_H
+#define LIBURING_COMPAT_H
+
+#if !defined(CONFIG_HAVE_KERNEL_RWF_T)
+typedef int __kernel_rwf_t;
+#endif
+
+#endif

src/io_uring.c

@@ -5,6 +5,7 @@
 #include <errno.h>
 #include <string.h>
 
+#include "compat.h"
 #include "io_uring.h"
 #include "liburing.h"
 #include "barrier.h"

src/liburing.h

@@ -2,6 +2,7 @@
 #define LIB_URING_H
 
 #include <sys/uio.h>
+#include "compat.h"
 #include "io_uring.h"
 
 /*

src/syscall.c

@@ -4,6 +4,7 @@
 #include <unistd.h>
 #include <sys/syscall.h>
 #include <sys/uio.h>
+#include "compat.h"
 #include "io_uring.h"
 
 #if defined(__x86_64)