1 files changed, 92 insertions, 0 deletions
diff --git a/gl/m4/getlogin_r.m4 b/gl/m4/getlogin_r.m4
new file mode 100644
index 0000000..c60ef34
--- /dev/null
+++ b/gl/m4/getlogin_r.m4
@@ -0,0 +1,92 @@
+#serial 13
+
+# Copyright (C) 2005-2007, 2009-2022 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.
+
+dnl From Derek Price
+dnl
+dnl Provide getlogin_r when the system lacks it.
+dnl
+
+AC_DEFUN([gl_FUNC_GETLOGIN_R],
+[
+  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+
+  dnl Persuade glibc <unistd.h> to declare getlogin_r().
+  dnl Persuade Solaris <unistd.h> to provide the POSIX compliant declaration of
+  dnl getlogin_r().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_DECLS_ONCE([getlogin_r])
+  if test $ac_cv_have_decl_getlogin_r = no; then
+    HAVE_DECL_GETLOGIN_R=0
+  fi
+
+  AC_CHECK_FUNCS_ONCE([getlogin_r])
+  if test $ac_cv_func_getlogin_r = no; then
+    HAVE_GETLOGIN_R=0
+  else
+    HAVE_GETLOGIN_R=1
+    dnl On Mac OS X 10.13 and OSF/1 5.1, getlogin_r returns a truncated result
+    dnl if the buffer is not large enough.
+    AC_REQUIRE([AC_CANONICAL_HOST])
+    AC_CACHE_CHECK([whether getlogin_r works with small buffers],
+      [gl_cv_func_getlogin_r_works],
+      [
+        dnl Initial guess, used when cross-compiling.
+changequote(,)dnl
+        case "$host_os" in
+                          # Guess no on Mac OS X, OSF/1.
+          darwin* | osf*) gl_cv_func_getlogin_r_works="guessing no" ;;
+                          # Guess yes otherwise.
+          *)              gl_cv_func_getlogin_r_works="guessing yes" ;;
+        esac
+changequote([,])dnl
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <stddef.h>
+#include <string.h>
+#include <unistd.h>
+#if !HAVE_DECL_GETLOGIN_R
+extern
+# ifdef __cplusplus
+"C"
+# endif
+int getlogin_r (char *, size_t);
+#endif
+int
+main (void)
+{
+  int result = 0;
+  char buf[100];
+
+  if (getlogin_r (buf, 0) == 0)
+    result |= 1;
+  if (getlogin_r (buf, 1) == 0)
+    result |= 2;
+  if (getlogin_r (buf, 100) == 0)
+    {
+      size_t n = strlen (buf);
+      if (getlogin_r (buf, n) == 0)
+        result |= 4;
+    }
+  return result;
+}]])],
+          [gl_cv_func_getlogin_r_works=yes],
+          [gl_cv_func_getlogin_r_works=no],
+          [:])
+      ])
+    case "$gl_cv_func_getlogin_r_works" in
+      *yes) ;;
+      *) REPLACE_GETLOGIN_R=1 ;;
+    esac
+  fi
+])
+
+AC_DEFUN([gl_PREREQ_GETLOGIN_R],
+[
+  AC_CHECK_DECLS_ONCE([getlogin])
+])