# gnupg-ttyname.m4

# Copyright (C) 2010-2012 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.

#

# This file is based on gnulib/m4/ttyname_r.m4 serial 8.

#

# gnupg_REPLACE_TTYNAME_R

#

# This macro is an extended version of AC_REPLACE_FUNCS(ttyname_r).

# It takes peculiarities in the implementation of ttyname_r in account.

#

# The macro HAVE_TTYNAME_R will be defined to 1 if the function

# exists; it will be defined to 0 if it does not exists or no

# declaration is available.

#

# The macro HAVE_POSIXDECL_TTYNAME_R is defined if ttyname_r conforms

# to the Posix declaration.

#

# The macro HAVE_BROKEN_TTYNAME_R is defined it ttyname_r does not work

# correctly with the supplied buffer size.  If this is defined the function

# will also be replaced.

#

# The macro REPLACE_TTYNAME_R is defined if ttyname_r is a replacement

# function.  This macro is useful for the definition of the prototype.

#

# If the macro "have_android_system" has a value of "yes", ttyname_r

# will also be replaced by our own function.

#

AC_DEFUN([gnupg_REPLACE_TTYNAME_R],

[

  AC_CHECK_HEADERS([unistd.h])

  AC_CHECK_DECLS_ONCE([ttyname_r])

  if test $ac_cv_have_decl_ttyname_r = no; then

    HAVE_DECL_TTYNAME_R=0

  fi

  AC_CHECK_FUNCS([ttyname_r])

  if test $ac_cv_func_ttyname_r = no; then

    HAVE_TTYNAME_R=0

    AC_LIBOBJ([ttyname_r])

    AC_DEFINE([REPLACE_TTYNAME_R],[1],

              [Define to 1 if ttyname_r is a replacement function.])

  else

    HAVE_TTYNAME_R=1

    dnl On MacOS X 10.4 (and Solaris 10 without __EXTENSIONS__)

    dnl the return type is 'char *', not 'int'.

    AC_CACHE_CHECK([whether ttyname_r is compatible with its POSIX signature],

      [gnupg_cv_func_ttyname_r_posix],

      [AC_COMPILE_IFELSE(

         [AC_LANG_PROGRAM(

            [[#include <stddef.h>

              #include <unistd.h>]],

            [[*ttyname_r (0, NULL, 0);]])

         ],

         [gnupg_cv_func_ttyname_r_posix=no],

         [gnupg_cv_func_ttyname_r_posix=yes])

      ])

    if test $gnupg_cv_func_ttyname_r_posix = no; then

      AC_LIBOBJ([ttyname_r])

      AC_DEFINE([REPLACE_TTYNAME_R],[1])

    elif test "$have_android_system" = yes; then

      # Android has ttyname and ttyname_r but they are only stubs and

      # print an annoying warning message.  Thus we need to replace

      # ttyname_r with our own dummy function.

      AC_LIBOBJ([ttyname_r])

      AC_DEFINE([REPLACE_TTYNAME_R],[1])

    else

      AC_DEFINE([HAVE_POSIXDECL_TTYNAME_R], [1],

        [Define if the ttyname_r function has a POSIX compliant declaration.])

      dnl On Solaris 10, both ttyname_r functions (the one with the non-POSIX

      dnl declaration and the one with the POSIX declaration) refuse to do

      dnl anything when the output buffer is less than 128 bytes large.

      dnl On OSF/1 5.1, ttyname_r ignores the buffer size and assumes the

      dnl buffer is large enough.

      AC_REQUIRE([AC_CANONICAL_HOST])

      AC_CACHE_CHECK([whether ttyname_r works with small buffers],

        [gnupg_cv_func_ttyname_r_works],

        [

          dnl Initial guess, used when cross-compiling or when /dev/tty cannot

          dnl be opened.

changequote(,)dnl

          case "$host_os" in

                      # Guess no on Solaris.

            solaris*) gnupg_cv_func_ttyname_r_works="guessing no" ;;

                      # Guess no on OSF/1.

            osf*)     gnupg_cv_func_ttyname_r_works="guessing no" ;;

                      # Guess yes otherwise.

            *)        gnupg_cv_func_ttyname_r_works="guessing yes" ;;

          esac

changequote([,])dnl

          AC_RUN_IFELSE(

            [AC_LANG_SOURCE([[

#include <fcntl.h>

#include <unistd.h>

int

main (void)

{

  int result = 0;

  int fd;

  char buf[31]; /* use any size < 128 here */

  fd = open ("/dev/tty", O_RDONLY);

  if (fd < 0)

    result |= 16;

  else if (ttyname_r (fd, buf, sizeof (buf)) != 0)

    result |= 17;

  else if (ttyname_r (fd, buf, 1) == 0)

    result |= 18;

  return result;

}]])],

            [gnupg_cv_func_ttyname_r_works=yes],

            [case $? in

               17 | 18) gnupg_cv_func_ttyname_r_works=no ;;

             esac],

            [:])

        ])

      case "$gnupg_cv_func_ttyname_r_works" in

        *yes) ;;

        *) AC_LIBOBJ([ttyname_r])

           AC_DEFINE([REPLACE_TTYNAME_R],[1])

           AC_DEFINE([HAVE_BROKEN_TTYNAME_R], [1],

                     [Define if ttyname_r is does not work with small buffers])

           ;;

      esac

    fi

  fi

])