# getcwd.m4 - check for working getcwd that is compatible with glibc

# Copyright (C) 2001, 2003-2007, 2009-2020 Free Software Foundation, Inc.

# This file is free software; the Free Software Foundation

# gives unlimited permission to copy and/or distribute it,

# with or without modifications, as long as this notice is preserved.

# Written by Paul Eggert.

# serial 18

AC_DEFUN([gl_FUNC_GETCWD_NULL],

  [

   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

   AC_CHECK_HEADERS_ONCE([unistd.h])

   AC_CACHE_CHECK([whether getcwd (NULL, 0) allocates memory for result],

     [gl_cv_func_getcwd_null],

     [AC_RUN_IFELSE([AC_LANG_PROGRAM([[

#	 include <stdlib.h>

#        if HAVE_UNISTD_H

#         include <unistd.h>

#        else /* on Windows with MSVC */

#         include <direct.h>

#        endif

#        ifndef getcwd

         char *getcwd ();

#        endif

]], [[

#if defined _WIN32 && ! defined __CYGWIN__

/* mingw cwd does not start with '/', but getcwd does allocate.

   However, mingw fails to honor non-zero size.  */

#else

           if (chdir ("/") != 0)

             return 1;

           else

             {

               char *f = getcwd (NULL, 0);

               if (! f)

                 return 2;

               if (f[0] != '/')

                 { free (f); return 3; }

               if (f[1] != '\0')

                 { free (f); return 4; }

               free (f);

               return 0;

             }

#endif

         ]])],

        [gl_cv_func_getcwd_null=yes],

        [gl_cv_func_getcwd_null=no],

        [[case "$host_os" in

                           # Guess yes on glibc systems.

            *-gnu* | gnu*) gl_cv_func_getcwd_null="guessing yes";;

                           # Guess yes on musl systems.

            *-musl*)       gl_cv_func_getcwd_null="guessing yes";;

                           # Guess yes on Cygwin.

            cygwin*)       gl_cv_func_getcwd_null="guessing yes";;

                           # If we don't know, obey --enable-cross-guesses.

            *)             gl_cv_func_getcwd_null="$gl_cross_guess_normal";;

          esac

        ]])])

])

AC_DEFUN([gl_FUNC_GETCWD_SIGNATURE],

[

  AC_CACHE_CHECK([for getcwd with POSIX signature],

    [gl_cv_func_getcwd_posix_signature],

    [AC_COMPILE_IFELSE(

      [AC_LANG_PROGRAM(

         [[#include <unistd.h>]],

         [[extern

           #ifdef __cplusplus

           "C"

           #endif

           char *getcwd (char *, size_t);

         ]])

      ],

      [gl_cv_func_getcwd_posix_signature=yes],

      [gl_cv_func_getcwd_posix_signature=no])

   ])

])

dnl Guarantee that getcwd will malloc with a NULL first argument.  Assumes

dnl that either the system getcwd is robust, or that calling code is okay

dnl with spurious failures when run from a directory with an absolute name

dnl larger than 4k bytes.

dnl

dnl Assumes that getcwd exists; if you are worried about obsolete

dnl platforms that lacked getcwd(), then you need to use the GPL module.

AC_DEFUN([gl_FUNC_GETCWD_LGPL],

[

  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])

  AC_REQUIRE([gl_FUNC_GETCWD_NULL])

  AC_REQUIRE([gl_FUNC_GETCWD_SIGNATURE])

  case $gl_cv_func_getcwd_null,$gl_cv_func_getcwd_posix_signature in

  *yes,yes) ;;

  *)

    dnl Minimal replacement lib/getcwd-lgpl.c.

    REPLACE_GETCWD=1

    ;;

  esac

])

dnl Check for all known getcwd bugs; useful for a program likely to be

dnl executed from an arbitrary location.

AC_DEFUN([gl_FUNC_GETCWD],

[

  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])

  AC_REQUIRE([gl_FUNC_GETCWD_NULL])

  AC_REQUIRE([gl_FUNC_GETCWD_SIGNATURE])

  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

  gl_abort_bug=no

  case "$host_os" in

    mingw*)

      gl_cv_func_getcwd_path_max=yes

      ;;

    *)

      gl_FUNC_GETCWD_PATH_MAX

      case "$gl_cv_func_getcwd_null" in

        *yes)

          gl_FUNC_GETCWD_ABORT_BUG([gl_abort_bug=yes])

          ;;

      esac

      ;;

  esac

  dnl Define HAVE_MINIMALLY_WORKING_GETCWD and HAVE_PARTLY_WORKING_GETCWD

  dnl if appropriate.

  case "$gl_cv_func_getcwd_path_max" in

    *"no" | *"no, it has the AIX bug") ;;

    *)

      AC_DEFINE([HAVE_MINIMALLY_WORKING_GETCWD], [1],

        [Define to 1 if getcwd minimally works, that is, its result can be

         trusted when it succeeds.])

      ;;

  esac

  case "$gl_cv_func_getcwd_path_max" in

    *"no, but it is partly working")

      AC_DEFINE([HAVE_PARTLY_WORKING_GETCWD], [1],

        [Define to 1 if getcwd works, except it sometimes fails when it

         shouldn't, setting errno to ERANGE, ENAMETOOLONG, or ENOENT.])

      ;;

    *"yes, but with shorter paths")

      AC_DEFINE([HAVE_GETCWD_SHORTER], [1],

        [Define to 1 if getcwd works, but with shorter paths

         than is generally tested with the replacement.])

      ;;

  esac

  if { case "$gl_cv_func_getcwd_null" in *yes) false;; *) true;; esac; } \

     || test $gl_cv_func_getcwd_posix_signature != yes \

     || { case "$gl_cv_func_getcwd_path_max" in *yes*) false;; *) true;; esac; } \

     || test $gl_abort_bug = yes; then

    REPLACE_GETCWD=1

  fi

])

# Prerequisites of lib/getcwd.c, when full replacement is in effect.

AC_DEFUN([gl_PREREQ_GETCWD],

[

  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])

  AC_REQUIRE([gl_CHECK_TYPE_STRUCT_DIRENT_D_INO])

  :

])