m4/open-slash.m4

# open-slash.m4 serial 1
dnl Copyright (C) 2007-2019 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

dnl Tests whether open() and creat() recognize a trailing slash.
dnl Sets gl_cv_func_open_slash.
AC_DEFUN([gl_OPEN_TRAILING_SLASH_BUG],
[
  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
  dnl open("foo/") should not create a file when the file name has a
  dnl trailing slash.  FreeBSD only has the problem on symlinks.
  AC_CHECK_FUNCS_ONCE([lstat])
  AC_CACHE_CHECK([whether open recognizes a trailing slash],
    [gl_cv_func_open_slash],
    [# Assume that if we have lstat, we can also check symlinks.
     if test $ac_cv_func_lstat = yes; then
       touch conftest.tmp
       ln -s conftest.tmp conftest.lnk
     fi
     AC_RUN_IFELSE(
       [AC_LANG_SOURCE([[
#include <fcntl.h>
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
int main ()
{
  int result = 0;
#if HAVE_LSTAT
  if (open ("conftest.lnk/", O_RDONLY) != -1)
    result |= 1;
#endif
  if (open ("conftest.sl/", O_CREAT, 0600) >= 0)
    result |= 2;
  return result;
}]])],
       [gl_cv_func_open_slash=yes],
       [gl_cv_func_open_slash=no],
       [
changequote(,)dnl
        case "$host_os" in
          freebsd* | aix* | hpux* | solaris2.[0-9] | solaris2.[0-9].*)
            gl_cv_func_open_slash="guessing no" ;;
          *)
            gl_cv_func_open_slash="guessing yes" ;;
        esac
changequote([,])dnl
       ])
     rm -f conftest.sl conftest.tmp conftest.lnk
    ])
  case "$gl_cv_func_open_slash" in
    *no)
      AC_DEFINE([OPEN_TRAILING_SLASH_BUG], [1],
        [Define to 1 if open() fails to recognize a trailing slash.])
      ;;
  esac
])