1# getrandom.m4 serial 8
2dnl Copyright 2020-2021 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7dnl Written by Paul Eggert.
8
9AC_DEFUN([gl_FUNC_GETRANDOM],
10[
11  AC_REQUIRE([gl_SYS_RANDOM_H_DEFAULTS])
12  AC_CHECK_FUNCS_ONCE([getrandom])
13  if test "$ac_cv_func_getrandom" != yes; then
14    HAVE_GETRANDOM=0
15  else
16    dnl On Solaris 11.4 the return type is 'int', not 'ssize_t'.
17    AC_CACHE_CHECK([whether getrandom is compatible with its GNU+BSD signature],
18      [gl_cv_func_getrandom_ok],
19      [AC_COMPILE_IFELSE(
20         [AC_LANG_PROGRAM(
21            [[/* Additional includes are needed before <sys/random.h> on uClibc
22                 and Mac OS X.  */
23              #include <sys/types.h>
24              #include <stdlib.h>
25              #include <sys/random.h>
26              ssize_t getrandom (void *, size_t, unsigned int);
27            ]],
28            [[]])
29         ],
30         [gl_cv_func_getrandom_ok=yes],
31         [gl_cv_func_getrandom_ok=no])
32      ])
33    if test $gl_cv_func_getrandom_ok = no; then
34      REPLACE_GETRANDOM=1
35    fi
36  fi
37
38  case "$host_os" in
39    mingw*)
40      AC_CHECK_HEADERS([bcrypt.h], [], [],
41        [[#include <windows.h>
42        ]])
43      AC_CACHE_CHECK([whether the bcrypt library is guaranteed to be present],
44        [gl_cv_lib_assume_bcrypt],
45        [AC_COMPILE_IFELSE(
46           [AC_LANG_PROGRAM(
47              [[#include <windows.h>]],
48              [[#if !(_WIN32_WINNT >= _WIN32_WINNT_WIN7)
49                  cannot assume it
50                #endif
51              ]])
52           ],
53           [gl_cv_lib_assume_bcrypt=yes],
54           [gl_cv_lib_assume_bcrypt=no])
55        ])
56      if test $gl_cv_lib_assume_bcrypt = yes; then
57        AC_DEFINE([HAVE_LIB_BCRYPT], [1],
58          [Define to 1 if the bcrypt library is guaranteed to be present.])
59        LIB_GETRANDOM='-lbcrypt'
60      else
61        LIB_GETRANDOM='-ladvapi32'
62      fi
63      ;;
64    *)
65      LIB_GETRANDOM= ;;
66  esac
67  AC_SUBST([LIB_GETRANDOM])
68])
69