Move uucplock into libutil and create a manual page.

4 files changed, 276 insertions, 3 deletions

diff --git a/lib/libutil/Makefile b/lib/libutil/Makefile
index 1f05dfd..2207317 100644
--- a/lib/libutil/Makefile
+++ b/lib/libutil/Makefile
@@ -5,9 +5,10 @@ SHLIB_MAJOR= 2
 SHLIB_MINOR= 2
 CFLAGS+=-Wall -DLIBC_SCCS -I${.CURDIR} -I/sys
 SRCS=	login.c login_tty.c logout.c logwtmp.c pty.c setproctitle.c \
-	login_cap.c login_class.c login_auth.c login_times.c login_ok.c
+	login_cap.c login_class.c login_auth.c login_times.c login_ok.c \
+	uucplock.c
 MAN3+=	login.3 login_tty.3 logout.3 logwtmp.3 pty.3 setproctitle.3 \
-	login_cap.3 login_class.3 login_times.3 login_ok.3
+	login_cap.3 login_class.3 login_times.3 login_ok.3 uucplock.3
 MAN5+=	login.conf.5
 MLINKS+= pty.3 openpty.3  pty.3 forkpty.3
 MLINKS+=login_cap.3 login_getclassbyname.3 login_cap.3 login_close.3 \
@@ -23,6 +24,7 @@ MLINKS+=login_times.3 parse_lt.3 login_times.3 in_ltm.3 \
 	login_times.3 in_lts.3
 MLINKS+=login_ok.3 auth_ttyok.3 login_ok.3 auth_hostok.3 \
 	login_ok.3 auth_timeok.3
+MLINKS+=uucplock.3 uu_lock.3 uucplock.3 uu_unlock.3
 
 beforeinstall:
 	${INSTALL} -C -o ${BINOWN} -g ${BINGRP} -m 444 ${.CURDIR}/libutil.h \
diff --git a/lib/libutil/libutil.h b/lib/libutil/libutil.h
index bcaf0d9..695a8cb 100644
--- a/lib/libutil/libutil.h
+++ b/lib/libutil/libutil.h
@@ -18,7 +18,7 @@
  * 5. Modifications may be freely made to this file providing the above
  *    conditions are met.
  *
- * $Id$
+ * $Id: libutil.h,v 1.4 1997/02/22 15:08:14 peter Exp $
  */
 
 #ifndef _LIBUTIL_H_
@@ -41,6 +41,8 @@ int	openpty __P((int *amaster, int *aslave, char *name,
 		     struct termios *termp, struct winsize *winp));
 int	forkpty __P((int *amaster, char *name,
 		     struct termios *termp, struct winsize *winp));
+int	uu_lock __P((char *ttyname));
+int	uu_unlock __P((char *ttyname));
 __END_DECLS
 
 #endif /* !_LIBUTIL_H_ */
diff --git a/lib/libutil/uucplock.3 b/lib/libutil/uucplock.3
new file mode 100644
index 0000000..a8b5df8
--- /dev/null
+++ b/lib/libutil/uucplock.3
@@ -0,0 +1,108 @@
+.\" 
+.\" Copyright (c) 1996 Brian Somers <brian@awfulhak.demon.co.uk>
+.\" 
+.\" 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.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``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 DEVELOPERS 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.
+.\" 
+.\" $Id$
+.\" "
+.Dd March 30, 1997
+.Os
+.Dt uucplock 3
+.Sh NAME
+.Nm uu_lock , 
+.Nm uu_unlock
+.Nd acquire and release control of a serial device
+.Sh SYNOPSIS
+.Fd #include <libutil.h>
+.Ft int
+.Fn uu_lock "char *ttyname"
+.Ft int
+.Fn uu_unlock "char *ttyname"
+.Pp
+Link with
+.Va -lutil
+on the
+.Xr cc 1
+command line.
+.Sh DESCRIPTION
+The
+.Fn uu_lock
+function attempts to create a lock file called
+.Dq /var/spool/lock/LCK..
+with a suffix given by the passed
+.Fa ttyname .
+If the file already exists, it is expected to contain the process
+id of the locking program.
+.Pp
+If the file does not already exist, or the owning process given by
+the process id found in the lock file is no longer running,
+.Fn uu_lock
+will write its own process id into the file and return success.
+.Pp
+.Fn uu_unlock
+removes the lockfile created by
+.Fn uu_lock
+for the given
+.Fa ttyname .
+Care should be taken that
+.Fn uu_lock
+was successful before calling
+.Fn uu_unlock .
+.Sh RETURN VALUES
+Both
+.Fn uu_lock
+and
+.Fn uu_unlock
+return 0 on success and -1 on failure.
+.Sh ERRORS
+On failure,
+.Fn uu_lock
+will log any unexpected errors using
+.Xr syslog 2 .
+If the lock already exists and contains the process id of a running
+process,
+.Fn uu_lock
+will silently fail.  The value of
+.Dv errno
+can not be used to determine the cause of failure.
+.Pp
+.Fn uu_unlock
+will set the global variable
+.Dv errno
+to reflect the reason that the lock file could not be removed.
+Refer to the description of
+.Xr unlink 2
+for further details.
+.Sh BUGS
+Locking is not atomic.  Should a race condition occur, it's entirely
+possible that both processes obtain the lock.
+.Pp
+It is possible that a stale lock is not recognised as such if a new
+processes is assigned the same processes id as the program that left
+the stale lock.
+.Pp
+The calling process must have write permissions to the
+.Dq /var/spool/lock
+directory.  There is no mechanism in place to ensure that the
+permissions of this directory are the same as those of the
+serial devices that might be locked.
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 */