#!/bin/sh

set -e

cc=${CC:-gcc}
cxx=${CXX:-g++}

for opt do
  optarg=$(expr "x$opt" : 'x[^=]*=\(.*\)' || true)
  case "$opt" in
  --help|-h) show_help=yes
  ;;
  --prefix=*) prefix="$optarg"
  ;;
  --includedir=*) includedir="$optarg"
  ;;
  --libdir=*) libdir="$optarg"
  ;;
  --libdevdir=*) libdevdir="$optarg"
  ;;
  --mandir=*) mandir="$optarg"
  ;;
  --datadir=*) datadir="$optarg"
  ;;
  --cc=*) cc="$optarg"
  ;;
  --cxx=*) cxx="$optarg"
  ;;
  --nolibc) liburing_nolibc="yes"
  ;;
  *)
    echo "ERROR: unknown option $opt"
    echo "Try '$0 --help' for more information"
    exit 1
  ;;
  esac
done

if test -z "$prefix"; then
  prefix=/usr
fi
if test -z "$includedir"; then
  includedir="$prefix/include"
fi
if test -z "$libdir"; then
  libdir="$prefix/lib"
fi
if test -z "$libdevdir"; then
  libdevdir="$prefix/lib"
fi
if test -z "$mandir"; then
  mandir="$prefix/man"
fi
if test -z "$datadir"; then
  datadir="$prefix/share"
fi

if test x"$libdir" = x"$libdevdir"; then
  relativelibdir=""
else
  relativelibdir="$libdir/"
fi

if test "$show_help" = "yes"; then
cat <<EOF

Usage: configure [options]
Options: [defaults in brackets after descriptions]
  --help                   print this message
  --prefix=PATH            install in PATH [$prefix]
  --includedir=PATH        install headers in PATH [$includedir]
  --libdir=PATH            install runtime libraries in PATH [$libdir]
  --libdevdir=PATH         install development libraries in PATH [$libdevdir]
  --mandir=PATH            install man pages in PATH [$mandir]
  --datadir=PATH           install shared data in PATH [$datadir]
  --cc=CMD                 use CMD as the C compiler
  --cxx=CMD                use CMD as the C++ compiler
  --nolibc                 build liburing without libc
EOF
exit 0
fi

TMP_DIRECTORY="$(mktemp -d)"
TMPC="$TMP_DIRECTORY/liburing-conf.c"
TMPC2="$TMP_DIRECTORY/liburing-conf-2.c"
TMPCXX="$TMP_DIRECTORY/liburing-conf-2.cpp"
TMPO="$TMP_DIRECTORY/liburing-conf.o"
TMPE="$TMP_DIRECTORY/liburing-conf.exe"

touch $TMPC $TMPC2 $TMPCXX $TMPO $TMPE

# 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 -rf $TMP_DIRECTORY" 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_cxx() {
    # Run the compiler, capturing its output to the log.
    echo $cxx "$@" >> config.log
    $cxx "$@" >> config.log 2>&1 || return $?
    return 0
}

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_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
}

compile_prog_cxx() {
  local_cflags="$1"
  local_ldflags="$2 $LIBS"
  echo "Compiling test case $3" >> config.log
  do_cxx $CFLAGS $local_cflags -o $TMPE $TMPCXX $LDFLAGS $local_ldflags
}

has() {
  type "$1" >/dev/null 2>&1
}

output_mak() {
  echo "$1=$2" >> $config_host_mak
}

output_sym() {
  output_mak "$1" "y"
  echo "#define $1" >> $config_host_h
}

print_and_output_mak() {
  print_config "$1" "$2"
  output_mak "$1" "$2"
}
print_and_output_mak "prefix" "$prefix"
print_and_output_mak "includedir" "$includedir"
print_and_output_mak "libdir" "$libdir"
print_and_output_mak "libdevdir" "$libdevdir"
print_and_output_mak "relativelibdir" "$relativelibdir"
print_and_output_mak "mandir" "$mandir"
print_and_output_mak "datadir" "$datadir"

##########################################
# check for compiler -Wstringop-overflow
stringop_overflow="no"
cat > $TMPC << EOF
#include <linux/fs.h>
int main(int argc, char **argv)
{
  return 0;
}
EOF
if compile_prog "-Werror -Wstringop-overflow=0" "" "stringop_overflow"; then
  stringop_overflow="yes"
fi
print_config "stringop_overflow" "$stringop_overflow"

##########################################
# check for compiler -Warryr-bounds
array_bounds="no"
cat > $TMPC << EOF
#include <linux/fs.h>
int main(int argc, char **argv)
{
  return 0;
}
EOF
if compile_prog "-Werror -Warray-bounds=0" "" "array_bounds"; then
  array_bounds="yes"
fi
print_config "array_bounds" "$array_bounds"


##########################################
# 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"

##########################################
# check for __kernel_timespec
__kernel_timespec="no"
cat > $TMPC << EOF
#include <linux/time.h>
#include <linux/time_types.h>
int main(int argc, char **argv)
{
  struct __kernel_timespec ts;
  ts.tv_sec = 0;
  ts.tv_nsec = 1;
  return 0;
}
EOF
if compile_prog "" "" "__kernel_timespec"; then
  __kernel_timespec="yes"
fi
print_config "__kernel_timespec" "$__kernel_timespec"

##########################################
# check for open_how
open_how="no"
cat > $TMPC << EOF
#include <sys/types.h>
#include <fcntl.h>
#include <string.h>
#include <linux/openat2.h>
int main(int argc, char **argv)
{
  struct open_how how;
  how.flags = 0;
  how.mode = 0;
  how.resolve = 0;
  return 0;
}
EOF
if compile_prog "" "" "open_how"; then
  open_how="yes"
fi
print_config "open_how" "$open_how"

##########################################
# check for statx
statx="no"
cat > $TMPC << EOF
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
int main(int argc, char **argv)
{
  struct statx x;

  return memset(&x, 0, sizeof(x)) != NULL;
}
EOF
if compile_prog "" "" "statx"; then
  statx="yes"
fi
print_config "statx" "$statx"

##########################################
# check for glibc statx
glibc_statx="no"
cat > $TMPC << EOF
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
int main(int argc, char **argv)
{
  struct statx x;

  return memset(&x, 0, sizeof(x)) != NULL;
}
EOF
if compile_prog "" "" "glibc_statx"; then
  glibc_statx="yes"
fi
print_config "glibc_statx" "$glibc_statx"

##########################################
# check for C++
has_cxx="no"
cat > $TMPCXX << EOF
#include <iostream>
int main(int argc, char **argv)
{
  std::cout << "Test";
  return 0;
}
EOF
if compile_prog_cxx "" "" "C++"; then
  has_cxx="yes"
fi
print_config "C++" "$has_cxx"

##########################################
# check for ucontext support
has_ucontext="no"
cat > $TMPC << EOF
#include <ucontext.h>
int main(int argc, char **argv)
{
  ucontext_t ctx;
  getcontext(&ctx);
  makecontext(&ctx, 0, 0);
  return 0;
}
EOF
if compile_prog "" "" "has_ucontext"; then
  has_ucontext="yes"
fi
print_config "has_ucontext" "$has_ucontext"

##########################################
# check for memfd_create(2)
has_memfd_create="no"
cat > $TMPC << EOF
#include <sys/mman.h>
int main(int argc, char **argv)
{
  int memfd = memfd_create("test", 0);
  return 0;
}
EOF
if compile_prog "-Werror=implicit-function-declaration" "" "has_memfd_create"; then
  has_memfd_create="yes"
fi
print_config "has_memfd_create" "$has_memfd_create"


#############################################################################
if test "$liburing_nolibc" = "yes"; then
  output_sym "CONFIG_NOLIBC"
else
  liburing_nolibc="no"
fi
print_config "liburing_nolibc" "$liburing_nolibc"

if test "$__kernel_rwf_t" = "yes"; then
  output_sym "CONFIG_HAVE_KERNEL_RWF_T"
fi
if test "$__kernel_timespec" = "yes"; then
  output_sym "CONFIG_HAVE_KERNEL_TIMESPEC"
fi
if test "$open_how" = "yes"; then
  output_sym "CONFIG_HAVE_OPEN_HOW"
fi
if test "$statx" = "yes"; then
  output_sym "CONFIG_HAVE_STATX"
fi
if test "$glibc_statx" = "yes"; then
  output_sym "CONFIG_HAVE_GLIBC_STATX"
fi
if test "$has_cxx" = "yes"; then
  output_sym "CONFIG_HAVE_CXX"
fi
if test "$has_ucontext" = "yes"; then
  output_sym "CONFIG_HAVE_UCONTEXT"
fi
if test "$stringop_overflow" = "yes"; then
  output_sym "CONFIG_HAVE_STRINGOP_OVERFLOW"
fi
if test "$array_bounds" = "yes"; then
  output_sym "CONFIG_HAVE_ARRAY_BOUNDS"
fi
if test "$has_memfd_create" = "yes"; then
  output_sym "CONFIG_HAVE_MEMFD_CREATE"
fi

echo "CC=$cc" >> $config_host_mak
print_config "CC" "$cc"
echo "CXX=$cxx" >> $config_host_mak
print_config "CXX" "$cxx"

# generate compat.h
compat_h="src/include/liburing/compat.h"
cat > $compat_h << EOF
/* SPDX-License-Identifier: MIT */
#ifndef LIBURING_COMPAT_H
#define LIBURING_COMPAT_H

EOF

if test "$__kernel_rwf_t" != "yes"; then
cat >> $compat_h << EOF
typedef int __kernel_rwf_t;

EOF
fi
if test "$__kernel_timespec" != "yes"; then
cat >> $compat_h << EOF
#include <stdint.h>

struct __kernel_timespec {
	int64_t		tv_sec;
	long long	tv_nsec;
};

EOF
else
cat >> $compat_h << EOF
#include <linux/time_types.h>

EOF
fi
if test "$open_how" != "yes"; then
cat >> $compat_h << EOF
#include <inttypes.h>

struct open_how {
	uint64_t	flags;
	uint64_t	mode;
	uint64_t	resolve;
};

EOF
else cat >> $compat_h << EOF
#include <linux/openat2.h>

EOF
fi
if [ "$glibc_statx" = "no" ] && [ "$statx" = "yes" ]; then
cat >> $compat_h << EOF
#include <sys/stat.h>

EOF
fi

cat >> $compat_h << EOF
#endif
EOF