From 7eb198c6424d784ecc2723f0457fd936b6ecf8d1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dag-Erling=20Sm=C3=B8rgrav?= <des@FreeBSD.org>
Date: Fri, 3 Aug 2007 06:32:45 +0000
Subject: [PATCH] Use fcntl(2)-style locks instead of less-portable
 flock(2)-style locks.

Approved by:	re (kensmith)
---
 lib/libutil/flopen.3  | 15 ++++++---------
 lib/libutil/flopen.c  | 11 +++++++----
 lib/libutil/pidfile.c | 14 ++++++++++----
 3 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/lib/libutil/flopen.3 b/lib/libutil/flopen.3
index 9025d65e304c..78792fc2cdc6 100644
--- a/lib/libutil/flopen.3
+++ b/lib/libutil/flopen.3
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 10, 2007
+.Dd July 30, 2007
 .Dt FLOPEN 3
 .Os
 .Sh NAME
@@ -46,12 +46,9 @@ The
 function opens or creates a file and acquires an exclusive lock on it.
 It is essentially equivalent with calling
 .Fn open
-with the same parameters followed by
-.Fn flock
-with an
-.Va operation
-argument of
-.Dv LOCK_EX ,
+with the same parameters and then acquiring a lock on the entire file
+using
+.Fn fcntl "F_SETLK" ,
 except that
 .Fn flopen
 will attempt to detect and handle races that may occur between opening
@@ -86,12 +83,12 @@ returns a valid file descriptor.
 Otherwise, it returns -1, and sets
 .Va errno
 as described in
-.Xr flock 2
+.Xr fcntl 2
 and
 .Xr open 2 .
 .Sh SEE ALSO
 .Xr errno 2 ,
-.Xr flock 2 ,
+.Xr fcntl 2 ,
 .Xr open 2
 .Sh AUTHORS
 .An -nosplit
diff --git a/lib/libutil/flopen.c b/lib/libutil/flopen.c
index 23742f7ceec7..f285ac571b86 100644
--- a/lib/libutil/flopen.c
+++ b/lib/libutil/flopen.c
@@ -43,6 +43,7 @@ flopen(const char *path, int flags, ...)
 {
 	int fd, operation, serrno, trunc;
 	struct stat sb, fsb;
+	struct flock lock;
 	mode_t mode;
 
 #ifdef O_EXLOCK
@@ -58,9 +59,11 @@ flopen(const char *path, int flags, ...)
 		va_end(ap);
 	}
 
-	operation = LOCK_EX;
-	if (flags & O_NONBLOCK)
-		operation |= LOCK_NB;
+	lock.l_type = (flags & O_RDONLY) ? F_RDLCK : F_WRLCK;
+	lock.l_start = 0;
+	lock.l_whence = SEEK_SET;
+	lock.l_len = 0;
+	operation = (flags & O_NONBLOCK) ? F_SETLK : F_SETLKW;
 
 	trunc = (flags & O_TRUNC);
 	flags &= ~O_TRUNC;
@@ -69,7 +72,7 @@ flopen(const char *path, int flags, ...)
 		if ((fd = open(path, flags, mode)) == -1)
 			/* non-existent or no access */
 			return (-1);
-		if (flock(fd, operation) == -1) {
+		if (fcntl(fd, operation, &lock) == -1) {
 			/* unsupported or interrupted */
 			serrno = errno;
 			close(fd);
diff --git a/lib/libutil/pidfile.c b/lib/libutil/pidfile.c
index 983d103b9ae1..c572551c9f83 100644
--- a/lib/libutil/pidfile.c
+++ b/lib/libutil/pidfile.c
@@ -31,13 +31,13 @@ __FBSDID("$FreeBSD$");
 #include <sys/file.h>
 #include <sys/stat.h>
 
+#include <errno.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <fcntl.h>
 #include <string.h>
-#include <err.h>
-#include <errno.h>
+
 #include <libutil.h>
 
 static int _pidfile_remove(struct pidfh *pfh, int freeit);
@@ -207,8 +207,14 @@ pidfile_close(struct pidfh *pfh)
 static int
 _pidfile_remove(struct pidfh *pfh, int freeit)
 {
+	struct flock lock;
 	int error;
 
+	lock.l_type = F_UNLCK;
+	lock.l_start = 0;
+	lock.l_whence = SEEK_SET;
+	lock.l_len = 0;
+
 	error = pidfile_verify(pfh);
 	if (error != 0) {
 		errno = error;
@@ -217,7 +223,7 @@ _pidfile_remove(struct pidfh *pfh, int freeit)
 
 	if (unlink(pfh->pf_path) == -1)
 		error = errno;
-	if (flock(pfh->pf_fd, LOCK_UN) == -1) {
+	if (fcntl(pfh->pf_fd, F_SETLK, &lock) == -1) {
 		if (error == 0)
 			error = errno;
 	}