1 files changed, 161 insertions, 0 deletions
diff --git a/lib/libutil/uucplock.c b/lib/libutil/uucplock.c
new file mode 100644
index 0000000..20eafe4
--- /dev/null
+++ b/lib/libutil/uucplock.c
@@ -0,0 +1,161 @@
+/*
+ * Copyright (c) 1988, 1993
+ *	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 const char sccsid[] = "@(#)uucplock.c	8.1 (Berkeley) 6/6/93";
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/file.h>
+#include <dirent.h>
+#include <errno.h>
+#ifndef USE_PERROR
+#include <syslog.h>
+#endif
+#include <unistd.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <paths.h>
+
+#define LOCKFMT "LCK..%s"
+
+/* Forward declarations */
+static int put_pid (int fd, pid_t pid);
+static pid_t get_pid (int fd);
+
+/*
+ * uucp style locking routines
+ * return: 0 - success
+ * 	  -1 - failure
+ */
+
+int uu_lock (char *ttyname)
+{
+	int fd;
+	pid_t pid;
+	char tbuf[sizeof(_PATH_UUCPLOCK) + MAXNAMLEN];
+
+	(void)sprintf(tbuf, _PATH_UUCPLOCK LOCKFMT, 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) {
+#ifndef USE_PERROR
+			syslog(LOG_ERR, "lock open: %m");
+#else
+			perror("lock open");
+#endif
+			return(-1);
+		}
+		if ((pid = get_pid (fd)) == -1) {
+#ifndef USE_PERROR
+			syslog(LOG_ERR, "lock read: %m");
+#else
+			perror("lock read");
+#endif
+			(void)close(fd);
+			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, (off_t) 0, L_SET) < 0) {
+#ifndef USE_PERROR
+			syslog(LOG_ERR, "lock lseek: %m");
+#else
+			perror("lock lseek");
+#endif
+			(void)close(fd);
+			return(-1);
+		}
+		/* fall out and finish the locking process */
+	}
+	pid = getpid();
+	if (!put_pid (fd, pid)) {
+#ifndef USE_PERROR
+		syslog(LOG_ERR, "lock write: %m");
+#else
+		perror("lock write");
+#endif
+		(void)close(fd);
+		(void)unlink(tbuf);
+		return(-1);
+	}
+	(void)close(fd);
+	return(0);
+}
+
+int uu_unlock (char *ttyname)
+{
+	char tbuf[sizeof(_PATH_UUCPLOCK) + MAXNAMLEN];
+
+	(void)sprintf(tbuf, _PATH_UUCPLOCK LOCKFMT, ttyname);
+	return(unlink(tbuf));
+}
+
+static int put_pid (int fd, pid_t pid)
+{
+	char buf[32];
+	int len;
+
+	len = sprintf (buf, "%10d\n", pid);
+	return write (fd, buf, len) == len;
+}
+
+static pid_t get_pid (int fd)
+{
+	int bytes_read;
+	char buf[32];
+	pid_t pid;
+
+	bytes_read = read (fd, buf, sizeof (buf) - 1);
+	if (bytes_read > 0) {
+		buf[bytes_read] = '\0';
+		pid = strtol (buf, (char **) NULL, 10);
+	} else
+		pid = -1;
+	return pid;
+}
+
+/* end of uucplock.c */