sync code with last improvements from OpenBSD

lib/libXau/AuFileName.c

@@ -0,0 +1,89 @@
+/*
+
+Copyright 1988, 1998  The Open Group
+
+Permission to use, copy, modify, distribute, and sell this software and its
+documentation for any purpose is hereby granted without fee, provided that
+the above copyright notice appear in all copies and that both that
+copyright notice and this permission notice appear in supporting
+documentation.
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+Except as contained in this notice, the name of The Open Group shall not be
+used in advertising or otherwise to promote the sale, use or other dealings
+in this Software without prior written authorization from The Open Group.
+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include <X11/Xauth.h>
+#include <X11/Xos.h>
+#include <assert.h>
+#include <stdlib.h>
+
+static char *buf = NULL;
+
+static void
+free_filename_buffer(void)
+{
+    free(buf);
+    buf = NULL;
+}
+
+char *
+XauFileName (void)
+{
+    const char *slashDotXauthority = "/.Xauthority";
+    char    *name;
+    static size_t	bsize;
+    static int atexit_registered = 0;
+#ifdef WIN32
+    char    dir[128];
+#endif
+    size_t  size;
+
+    if ((name = getenv ("XAUTHORITY")))
+	return name;
+    name = getenv ("HOME");
+    if (!name) {
+#ifdef WIN32
+	if ((name = getenv("USERNAME"))) {
+	    snprintf(dir, sizeof(dir), "/users/%s", name);
+	    name = dir;
+	}
+	if (!name)
+#endif
+	return NULL;
+    }
+    size = strlen (name) + strlen(&slashDotXauthority[1]) + 2;
+    if ((size > bsize) || (buf == NULL)) {
+	free (buf);
+        assert(size > 0);
+	buf = malloc (size);
+	if (!buf) {
+	    bsize = 0;
+	    return NULL;
+	}
+
+        if (!atexit_registered) {
+            atexit(free_filename_buffer);
+            atexit_registered = 1;
+        }
+
+	bsize = size;
+    }
+    snprintf (buf, bsize, "%s%s", name,
+              slashDotXauthority + (name[0] == '/' && name[1] == '\0' ? 1 : 0));
+    return buf;
+}