386BSD 0.1 development

Work on file usr/src/usr.bin/tip/uucplock.c

Co-Authored-By: Lynne Greer Jolitz <ljolitz@cardio.ucsf.edu>
Synthesized-from: 386BSD-0.1

diff --git a/usr/src/usr.bin/tip/uucplock.c b/usr/src/usr.bin/tip/uucplock.c
new file mode 100644 (file)
index 0000000..07c6f20
--- /dev/null
+++ b/usr/src/usr.bin/tip/uucplock.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 1988 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the University of
+ *     California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+static char sccsid[] = "@(#)uucplock.c 5.5 (Berkeley) 6/1/90";
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/file.h>
+#include <sys/dir.h>
+#include <errno.h>
+#include "pathnames.h"
+
+/* 
+ * uucp style locking routines
+ * return: 0 - success
+ *       -1 - failure
+ */
+
+uu_lock(ttyname)
+       char *ttyname;
+{
+       extern int errno;
+       int fd, pid;
+       char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
+       off_t lseek();
+
+       (void)sprintf(tbuf, _PATH_LOCKDIRNAME, ttyname);
+       fd = open(tbuf, O_RDWR|O_CREAT|O_EXCL, 0660);
+       if (fd < 0) {
+               /*
+                * file is already locked
+                * check to see if the process holding the lock still exists
+                */
+               fd = open(tbuf, O_RDWR, 0);
+               if (fd < 0) {
+                       perror("lock open");
+                       return(-1);
+               }
+               if (read(fd, &pid, sizeof(pid)) != sizeof(pid)) {
+                       (void)close(fd);
+                       perror("lock read");
+                       return(-1);
+               }
+
+               if (kill(pid, 0) == 0 || errno != ESRCH) {
+                       (void)close(fd);        /* process is still running */
+                       return(-1);
+               }
+               /*
+                * The process that locked the file isn't running, so
+                * we'll lock it ourselves
+                */
+               if (lseek(fd, 0L, L_SET) < 0) {
+                       (void)close(fd);
+                       perror("lock lseek");
+                       return(-1);
+               }
+               /* fall out and finish the locking process */
+       }
+       pid = getpid();
+       if (write(fd, (char *)&pid, sizeof(pid)) != sizeof(pid)) {
+               (void)close(fd);
+               (void)unlink(tbuf);
+               perror("lock write");
+               return(-1);
+       }
+       (void)close(fd);
+       return(0);
+}
+
+uu_unlock(ttyname)
+       char *ttyname;
+{
+       char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
+
+       (void)sprintf(tbuf, _PATH_LOCKDIRNAME, ttyname);
+       return(unlink(tbuf));
+}