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diff --git a/lib/libc/gen/lockf.3 b/lib/libc/gen/lockf.3
new file mode 100644
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--- /dev/null
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@@ -0,0 +1,249 @@
+.\" $NetBSD: lockf.3,v 1.2 1998/02/05 18:47:28 perry Exp $
+.\"
+.\" Copyright (c) 1997 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to The NetBSD Foundation
+.\" by Klaus Klein and S.P. Zeidler.
+.\"
+.\" 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 NetBSD
+.\"        Foundation, Inc. and its contributors.
+.\" 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
+.\"
+.Dd December 19, 1997
+.Dt LOCKF 3
+.Os NetBSD 1.4
+.Sh NAME
+.Nm lockf
+.Nd record locking on files
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.Fd #include <unistd.h>
+.Ft int
+.Fn lockf "int filedes" "int function" "off_t size"
+.Sh DESCRIPTION
+The
+.Fn lockf
+function allows sections of a file to be locked with advisory-mode locks.
+Calls to
+.Fn lockf
+from other processes which attempt to lock the locked file section will
+either return an error value or block until the section becomes unlocked.
+All the locks for a process are removed when the process terminates.
+.Pp
+The argument
+.Fa filedes
+is an open file descriptor.
+The file descriptor must have been opened either for write-only
+.Dv ( O_WRONLY )
+or read/write
+.Dv ( O_RDWR )
+operation.
+.Pp
+The
+.Fa function
+argument is a control value which specifies the action to be taken.
+The permissible values for
+.Fa function
+are as follows:
+.Bl -tag -width F_ULOCKXX -compact -offset indent
+.It Sy Function
+.Sy Description
+.It Dv F_ULOCK
+unlock locked sections
+.It Dv F_LOCK
+lock a section for exclusive use
+.It Dv F_TLOCK
+test and lock a section for exclusive use
+.It Dv F_TEST
+test a section for locks by other processes
+.El
+.Pp
+.Dv F_ULOCK
+removes locks from a section of the file;
+.Dv F_LOCK
+and
+.Dv F_TLOCK
+both lock a section of a file if the section is available;
+.Dv F_TEST
+detects if a lock by another process is present on the specified section.
+.Pp
+The
+.Fa size
+argument is the number of contiguous bytes to be locked or
+unlocked. The section to be locked or unlocked starts at the current
+offset in the file and extends forward for a positive size or backward
+for a negative size (the preceding bytes up to but not including the
+current offset). However, it is not permitted to lock a section that
+starts or extends before the beginning of the file.
+If
+.Fa size
+is 0, the section from the current offset through the largest possible
+file offset is locked (that is, from the current offset through the
+present or any future end-of-file).
+.Pp
+The sections locked with
+.Dv F_LOCK
+or
+.Dv F_TLOCK
+may, in whole or in part, contain or be contained by a previously
+locked section for the same process. When this occurs, or if adjacent
+locked sections would occur, the sections are combined into a single
+locked section. If the request would cause the number of locks to
+exceed a system-imposed limit, the request will fail.
+.Pp
+.Dv F_LOCK
+and
+.Dv F_TLOCK
+requests differ only by the action taken if the section is not
+available.
+.Dv F_LOCK
+blocks the calling process until the section is available.
+.Dv F_TLOCK
+makes the function fail if the section is already locked by another
+process.
+.Pp
+File locks are released on first close by the locking process of any
+file descriptor for the file.
+.Pp
+.Dv F_ULOCK
+requests release (wholly or in part) one or more locked sections
+controlled by the process. Locked sections will be unlocked starting
+at the current file offset through
+.Fa size
+bytes or to the end of file if size is 0. When all of a locked section
+is not released (that is, when the beginning or end of the area to be
+unlocked falls within a locked section), the remaining portions of
+that section are still locked by the process. Releasing the center
+portion of a locked section will cause the remaining locked beginning
+and end portions to become two separate locked sections. If the
+request would cause the number of locks in the system to exceed a
+system-imposed limit, the request will fail.
+.Pp
+An
+.Dv F_ULOCK
+request in which size is non-zero and the offset of the last byte of
+the requested section is the maximum value for an object of type
+off_t, when the process has an existing lock in which size is 0 and
+which includes the last byte of the requested section, will be treated
+as a request to unlock from the start of the requested section with a
+size equal to 0. Otherwise an
+.Dv F_ULOCK
+request will attempt to unlock only the requested section.
+.Pp
+A potential for deadlock occurs if a process controlling a locked
+region is put to sleep by attempting to lock the locked region of
+another process.  This implementation detects that sleeping until a
+locked region is unlocked would cause a deadlock and fails with an
+.Er EDEADLK
+error.
+.Pp
+.Fn lockf ,
+.Xr fcntl 2
+and
+.Xr flock 2
+locks may be safely used concurrently.
+.Pp
+Blocking on a section is interrupted by any signal.
+.Sh RETURN VALUES
+If successful, the
+.Fn lockf
+function returns 0.
+Otherwise, it returns -1, sets
+.Dv errno
+to indicate an error, and existing locks are not changed.
+.Sh ERRORS
+.Fn lockf
+will fail if:
+.Bl -tag -width Er
+.It Bq Er EAGAIN
+The argument
+.Fa function
+is
+.Dv F_TLOCK
+or
+.Dv F_TEST
+and the section is already locked by another process.
+.It Bq Er EBADF
+The argument
+.Fa filedes
+is not a valid open file descriptor.
+.Pp
+The argument
+.Fa function
+is
+.Dv F_LOCK
+or
+.Dv F_TLOCK ,
+and
+.Fa filedes
+is not a valid file descriptor open for writing.
+.It Bq Er EDEADLK
+The argument
+.Fa function
+is
+.Dv F_LOCK
+and a deadlock is detected.
+.It Bq Er EINTR
+The argument
+.Fa function
+is F_LOCK
+and
+.Fn lockf
+was interrupted by the delivery of a signal.
+.It Bq Er EINVAL
+The argument
+.Fa function
+is not one of
+.Dv F_ULOCK ,
+.Dv F_LOCK ,
+.Dv F_TLOCK
+or
+.Dv F_TEST .
+.Pp
+The argument
+.Fa filedes
+refers to a file that does not support locking.
+.It Bq Er ENOLCK
+The argument
+.Fa function
+is
+.Dv F_ULOCK ,
+.Dv F_LOCK
+or
+.Dv F_TLOCK ,
+and satisfying the lock or unlock request would result in the number
+of locked regions in the system exceeding a system-imposed limit.
+.Sh SEE ALSO
+.Xr fcntl 2 ,
+.Xr flock 2
+.Sh STANDARDS
+The
+.Fn lockf
+function conforms to
+.St -xpg4.2 .
diff --git a/lib/libc/gen/lockf.c b/lib/libc/gen/lockf.c
new file mode 100644
index 0000000..0419390
--- /dev/null
+++ b/lib/libc/gen/lockf.c
@@ -0,0 +1,96 @@
+/*	$NetBSD: lockf.c,v 1.1 1997/12/20 20:23:18 kleink Exp $	*/
+
+/*-
+ * Copyright (c) 1997 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Klaus Klein.
+ *
+ * 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 NetBSD
+ *        Foundation, Inc. and its contributors.
+ * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
+ */
+
+#include <sys/cdefs.h>
+#if defined(LIBC_SCCS) && !defined(lint)
+__RCSID("$NetBSD: lockf.c,v 1.1 1997/12/20 20:23:18 kleink Exp $");
+#endif
+
+#include "namespace.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#ifdef __weak_alias
+__weak_alias(lockf,_lockf);
+#endif
+
+
+int
+lockf(filedes, function, size)
+	int filedes;
+	int function;
+	off_t size;
+{
+	struct flock fl;
+	int cmd;
+
+	fl.l_start = 0;
+	fl.l_len = size;
+	fl.l_whence = SEEK_CUR;
+
+	switch (function) {
+	case F_ULOCK:
+		cmd = F_SETLK;
+		fl.l_type = F_UNLCK;
+		break;
+	case F_LOCK:
+		cmd = F_SETLKW;
+		fl.l_type = F_WRLCK;
+		break;
+	case F_TLOCK:
+		cmd = F_SETLK;
+		fl.l_type = F_WRLCK;
+		break;
+	case F_TEST:
+		fl.l_type = F_WRLCK;
+		if (fcntl(filedes, F_GETLK, &fl) == -1)
+			return (-1);
+		if (fl.l_type == F_UNLCK || fl.l_pid == getpid())
+			return (0);
+		errno = EAGAIN;
+		return (-1);
+		/* NOTREACHED */
+	default:
+		errno = EINVAL;
+		return (-1);
+		/* NOTREACHED */
+	}
+
+	return (fcntl(filedes, cmd, &fl));
+}