sync code with last improvements from OpenBSD

lib/libXau/AuLock.c

@@ -0,0 +1,108 @@
+/*
+
+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 <sys/stat.h>
+#include <errno.h>
+#include <time.h>
+#define Time_t time_t
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+#ifdef WIN32
+# include <X11/Xwindows.h>
+# define link rename
+#endif
+
+int
+XauLockAuth (
+_Xconst char *file_name,
+int	retries,
+int	timeout,
+long	dead)
+{
+    char	creat_name[1025], link_name[1025];
+    struct stat	statb;
+    Time_t	now;
+    int		creat_fd = -1;
+
+    if (strlen (file_name) > 1022)
+	return LOCK_ERROR;
+    snprintf (creat_name, sizeof(creat_name), "%s-c", file_name);
+    snprintf (link_name, sizeof(link_name), "%s-l", file_name);
+    if (stat (creat_name, &statb) != -1) {
+	now = time ((Time_t *) 0);
+	/*
+	 * NFS may cause ctime to be before now, special
+	 * case a 0 deadtime to force lock removal
+	 */
+	if (dead == 0 || now - statb.st_ctime > dead) {
+	    (void) remove (creat_name);
+	    (void) remove (link_name);
+	}
+    }
+
+    while (retries > 0) {
+	if (creat_fd == -1) {
+	    creat_fd = open (creat_name, O_WRONLY | O_CREAT | O_EXCL, 0600);
+	    if (creat_fd == -1) {
+		if (errno != EACCES && errno != EEXIST)
+		    return LOCK_ERROR;
+	    } else
+		(void) close (creat_fd);
+	}
+	if (creat_fd != -1) {
+#ifdef HAVE_PATHCONF
+	    /* The file system may not support hard links, and pathconf should tell us that. */
+	    if (1 == pathconf(creat_name, _PC_LINK_MAX)) {
+		if (-1 == rename(creat_name, link_name)) {
+		    /* Is this good enough?  Perhaps we should retry.  TEST */
+		    return LOCK_ERROR;
+		} else {
+		    return LOCK_SUCCESS;
+		}
+	    } else
+#endif
+	    {
+	    	if (link (creat_name, link_name) != -1)
+		    return LOCK_SUCCESS;
+		if (errno == ENOENT) {
+		    creat_fd = -1;	/* force re-creat next time around */
+		    continue;
+	    	}
+	    	if (errno != EEXIST)
+		    return LOCK_ERROR;
+	   }
+	}
+	(void) sleep ((unsigned) timeout);
+	--retries;
+    }
+    return LOCK_TIMEOUT;
+}