1 files changed, 169 insertions, 0 deletions
diff --git a/m4/check-libc.m4 b/m4/check-libc.m4
new file mode 100644
index 0000000..e511f6d
--- /dev/null
+++ b/m4/check-libc.m4
@@ -0,0 +1,169 @@
+AC_DEFUN([CHECK_LIBC_COMPAT], [
+# Check for libc headers
+AC_CHECK_HEADERS([err.h readpassphrase.h])
+# Check for general libc functions
+AC_CHECK_FUNCS([asprintf freezero memmem])
+AC_CHECK_FUNCS([readpassphrase reallocarray recallocarray])
+AC_CHECK_FUNCS([strlcat strlcpy strndup strnlen strsep strtonum])
+AC_CHECK_FUNCS([timegm _mkgmtime timespecsub])
+AC_CHECK_FUNCS([getprogname syslog syslog_r])
+AC_CACHE_CHECK([for getpagesize], ac_cv_func_getpagesize, [
+	AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+// Since Android NDK v16 getpagesize is defined as inline inside unistd.h
+#ifdef __ANDROID__
+#	include <unistd.h>
+#endif
+		]], [[
+	getpagesize();
+]])],
+	[ ac_cv_func_getpagesize="yes" ],
+	[ ac_cv_func_getpagesize="no"
+	])
+])
+AM_CONDITIONAL([HAVE_ASPRINTF], [test "x$ac_cv_func_asprintf" = xyes])
+AM_CONDITIONAL([HAVE_FREEZERO], [test "x$ac_cv_func_freezero" = xyes])
+AM_CONDITIONAL([HAVE_GETPAGESIZE], [test "x$ac_cv_func_getpagesize" = xyes])
+AM_CONDITIONAL([HAVE_MEMMEM], [test "x$ac_cv_func_memmem" = xyes])
+AM_CONDITIONAL([HAVE_READPASSPHRASE], [test "x$ac_cv_func_readpassphrase" = xyes])
+AM_CONDITIONAL([HAVE_REALLOCARRAY], [test "x$ac_cv_func_reallocarray" = xyes])
+AM_CONDITIONAL([HAVE_RECALLOCARRAY], [test "x$ac_cv_func_recallocarray" = xyes])
+AM_CONDITIONAL([HAVE_STRLCAT], [test "x$ac_cv_func_strlcat" = xyes])
+AM_CONDITIONAL([HAVE_STRLCPY], [test "x$ac_cv_func_strlcpy" = xyes])
+AM_CONDITIONAL([HAVE_STRNDUP], [test "x$ac_cv_func_strndup" = xyes])
+AM_CONDITIONAL([HAVE_STRNLEN], [test "x$ac_cv_func_strnlen" = xyes])
+AM_CONDITIONAL([HAVE_STRSEP], [test "x$ac_cv_func_strsep" = xyes])
+AM_CONDITIONAL([HAVE_STRTONUM], [test "x$ac_cv_func_strtonum" = xyes])
+AM_CONDITIONAL([HAVE_TIMEGM], [test "x$ac_cv_func_timegm" = xyes])
+AM_CONDITIONAL([HAVE_GETPROGNAME], [test "x$ac_cv_func_getprogname" = xyes])
+AM_CONDITIONAL([HAVE_SYSLOG], [test "x$ac_cv_func_syslog" = xyes])
+AM_CONDITIONAL([HAVE_SYSLOG_R], [test "x$ac_cv_func_syslog_r" = xyes])
+])
+
+AC_DEFUN([CHECK_SYSCALL_COMPAT], [
+AC_CHECK_FUNCS([accept4 pipe2 pledge poll socketpair])
+AM_CONDITIONAL([HAVE_ACCEPT4], [test "x$ac_cv_func_accept4" = xyes])
+AM_CONDITIONAL([HAVE_PIPE2], [test "x$ac_cv_func_pipe2" = xyes])
+AM_CONDITIONAL([HAVE_PLEDGE], [test "x$ac_cv_func_pledge" = xyes])
+AM_CONDITIONAL([HAVE_POLL], [test "x$ac_cv_func_poll" = xyes])
+AM_CONDITIONAL([HAVE_SOCKETPAIR], [test "x$ac_cv_func_socketpair" = xyes])
+])
+
+AC_DEFUN([CHECK_B64_NTOP], [
+AC_SEARCH_LIBS([b64_ntop],[resolv])
+AC_SEARCH_LIBS([__b64_ntop],[resolv])
+AC_CACHE_CHECK([for b64_ntop], ac_cv_have_b64_ntop_arg, [
+	AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <resolv.h>
+		]], [[ b64_ntop(NULL, 0, NULL, 0); ]])],
+	[ ac_cv_have_b64_ntop_arg="yes" ],
+	[ ac_cv_have_b64_ntop_arg="no"
+	])
+])
+AM_CONDITIONAL([HAVE_B64_NTOP], [test "x$ac_cv_func_b64_ntop_arg" = xyes])
+])
+
+AC_DEFUN([CHECK_CRYPTO_COMPAT], [
+# Check crypto-related libc functions and syscalls
+AC_CHECK_FUNCS([arc4random arc4random_buf arc4random_uniform])
+AC_CHECK_FUNCS([explicit_bzero getauxval])
+
+AC_CACHE_CHECK([for getentropy], ac_cv_func_getentropy, [
+	AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+#include <sys/types.h>
+#include <unistd.h>
+
+/*
+ * Explanation:
+ *
+ *   - iOS <= 10.1 fails because of missing sys/random.h
+ *
+ *   - in macOS 10.12 getentropy is not tagged as introduced in
+ *     10.12 so we cannot use it for target < 10.12
+ */
+#ifdef __APPLE__
+#  include <AvailabilityMacros.h>
+#  include <TargetConditionals.h>
+
+# if (TARGET_OS_IPHONE || TARGET_OS_SIMULATOR)
+#  include <sys/random.h> /* Not available as of iOS <= 10.1 */
+# else
+
+#  include <sys/random.h> /* Pre 10.12 systems should die here */
+
+/* Based on: https://gitweb.torproject.org/tor.git/commit/?id=16fcbd21 */
+#  ifndef MAC_OS_X_VERSION_10_12
+#    define MAC_OS_X_VERSION_10_12 101200 /* Robustness */
+#  endif
+#  if defined(MAC_OS_X_VERSION_MIN_REQUIRED)
+#    if MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_12
+#      error "Targeting on Mac OSX 10.11 or earlier"
+#    endif
+#  endif
+
+# endif
+#endif /* __APPLE__ */
+		]], [[
+	char buffer;
+	(void)getentropy(&buffer, sizeof (buffer));
+]])],
+	[ ac_cv_func_getentropy="yes" ],
+	[ ac_cv_func_getentropy="no"
+	])
+])
+
+AC_CHECK_FUNCS([timingsafe_bcmp timingsafe_memcmp])
+AM_CONDITIONAL([HAVE_ARC4RANDOM], [test "x$ac_cv_func_arc4random" = xyes])
+AM_CONDITIONAL([HAVE_ARC4RANDOM_BUF], [test "x$ac_cv_func_arc4random_buf" = xyes])
+AM_CONDITIONAL([HAVE_ARC4RANDOM_UNIFORM], [test "x$ac_cv_func_arc4random_uniform" = xyes])
+AM_CONDITIONAL([HAVE_EXPLICIT_BZERO], [test "x$ac_cv_func_explicit_bzero" = xyes])
+AM_CONDITIONAL([HAVE_GETENTROPY], [test "x$ac_cv_func_getentropy" = xyes])
+AM_CONDITIONAL([HAVE_TIMINGSAFE_BCMP], [test "x$ac_cv_func_timingsafe_bcmp" = xyes])
+AM_CONDITIONAL([HAVE_TIMINGSAFE_MEMCMP], [test "x$ac_cv_func_timingsafe_memcmp" = xyes])
+
+# Override arc4random_buf implementations with known issues
+AM_CONDITIONAL([HAVE_ARC4RANDOM_BUF],
+	[test "x$USE_BUILTIN_ARC4RANDOM" != xyes \
+	   -a "x$ac_cv_func_arc4random_buf" = xyes])
+
+# Check for getentropy fallback dependencies
+AC_CHECK_FUNCS([getauxval])
+AC_SEARCH_LIBS([dl_iterate_phdr],[dl])
+AC_CHECK_FUNCS([dl_iterate_phdr])
+
+AC_SEARCH_LIBS([pthread_once],[pthread])
+AC_SEARCH_LIBS([pthread_mutex_lock],[pthread])
+AC_SEARCH_LIBS([clock_gettime],[rt posix4])
+AC_CHECK_FUNCS([clock_gettime])
+AM_CONDITIONAL([HAVE_CLOCK_GETTIME], [test "x$ac_cv_func_clock_gettime" = xyes])
+])
+
+AC_DEFUN([CHECK_VA_COPY], [
+AC_CACHE_CHECK([whether va_copy exists], ac_cv_have_va_copy, [
+	AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+#include <stdarg.h>
+va_list x,y;
+		]], [[ va_copy(x,y); ]])],
+	[ ac_cv_have_va_copy="yes" ],
+	[ ac_cv_have_va_copy="no"
+	])
+])
+if test "x$ac_cv_have_va_copy" = "xyes" ; then
+	AC_DEFINE([HAVE_VA_COPY], [1], [Define if va_copy exists])
+fi
+
+AC_CACHE_CHECK([whether __va_copy exists], ac_cv_have___va_copy, [
+	AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+#include <stdarg.h>
+va_list x,y;
+		]], [[ __va_copy(x,y); ]])],
+	[ ac_cv_have___va_copy="yes" ], [ ac_cv_have___va_copy="no"
+	])
+])
+if test "x$ac_cv_have___va_copy" = "xyes" ; then
+	AC_DEFINE([HAVE___VA_COPY], [1], [Define if __va_copy exists])
+fi
+])