gnulib/import/m4/getlogin_r.m4

   1 #serial 12
   2
   3 # Copyright (C) 2005-2007, 2009-2019 Free Software Foundation, Inc.
   4 #
   5 # This file is free software; the Free Software Foundation
   6 # gives unlimited permission to copy and/or distribute it,
   7 # with or without modifications, as long as this notice is preserved.
   8
   9 dnl From Derek Price
  10 dnl
  11 dnl Provide getlogin_r when the system lacks it.
  12 dnl
  13
  14 AC_DEFUN([gl_FUNC_GETLOGIN_R],
  15 [
  16   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
  17
  18   dnl Persuade glibc <unistd.h> to declare getlogin_r().
  19   dnl Persuade Solaris <unistd.h> to provide the POSIX compliant declaration of
  20   dnl getlogin_r().
  21   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
  22
  23   AC_CHECK_DECLS_ONCE([getlogin_r])
  24   if test $ac_cv_have_decl_getlogin_r = no; then
  25     HAVE_DECL_GETLOGIN_R=0
  26   fi
  27
  28   AC_CHECK_FUNCS_ONCE([getlogin_r])
  29   if test $ac_cv_func_getlogin_r = no; then
  30     HAVE_GETLOGIN_R=0
  31   else
  32     HAVE_GETLOGIN_R=1
  33     dnl On Mac OS X 10.12 and OSF/1 5.1, getlogin_r returns a truncated result
  34     dnl if the buffer is not large enough.
  35     AC_REQUIRE([AC_CANONICAL_HOST])
  36     AC_CACHE_CHECK([whether getlogin_r works with small buffers],
  37       [gl_cv_func_getlogin_r_works],
  38       [
  39         dnl Initial guess, used when cross-compiling.
  40 changequote(,)dnl
  41         case "$host_os" in
  42                           # Guess no on Mac OS X, OSF/1.
  43           darwin* | osf*) gl_cv_func_getlogin_r_works="guessing no" ;;
  44                           # Guess yes otherwise.
  45           *)              gl_cv_func_getlogin_r_works="guessing yes" ;;
  46         esac
  47 changequote([,])dnl
  48         AC_RUN_IFELSE(
  49           [AC_LANG_SOURCE([[
  50 #include <stddef.h>
  51 #include <string.h>
  52 #include <unistd.h>
  53 #if !HAVE_DECL_GETLOGIN_R
  54 extern
  55 # ifdef __cplusplus
  56 "C"
  57 # endif
  58 int getlogin_r (char *, size_t);
  59 #endif
  60 int
  61 main (void)
  62 {
  63   int result = 0;
  64   char buf[100];
  65
  66   if (getlogin_r (buf, 0) == 0)
  67     result |= 1;
  68   if (getlogin_r (buf, 1) == 0)
  69     result |= 2;
  70   if (getlogin_r (buf, 100) == 0)
  71     {
  72       size_t n = strlen (buf);
  73       if (getlogin_r (buf, n) == 0)
  74         result |= 4;
  75     }
  76   return result;
  77 }]])],
  78           [gl_cv_func_getlogin_r_works=yes],
  79           [gl_cv_func_getlogin_r_works=no],
  80           [:])
  81       ])
  82     case "$gl_cv_func_getlogin_r_works" in
  83       *yes) ;;
  84       *) REPLACE_GETLOGIN_R=1 ;;
  85     esac
  86   fi
  87 ])
  88
  89 AC_DEFUN([gl_PREREQ_GETLOGIN_R],
  90 [
  91   AC_CHECK_DECLS_ONCE([getlogin])
  92 ])