From: William F. Jolitz <wjolitz@soda.berkeley.edu>
Date: Sat, 18 Apr 1992 20:51:02 +0000 (-0800)
Subject: 386BSD 0.1 development
X-Git-Tag: 386BSD-0.1~474
X-Git-Url: https://git.subgeniuskitty.com/unix-history/.git/commitdiff_plain/6cdf4859f2aec8a7bb209f882d2a9e507b7acc4d?ds=inline

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
index 0000000000..07c6f20ec6
--- /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));
+}