-// mmc -- Mattermost client
-// Copyright (C) 2023 Sergey Matveev <stargrave@stargrave.org>
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as
-// published by the Free Software Foundation, either version 3 of the
-// License.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program. If not, see <http://www.gnu.org/licenses/>.
-
-package mmc
-
-import (
- "io"
- "os"
-
- "golang.org/x/sys/unix"
-)
-
-func Lock(what string) (func(), error) {
- fd, err := os.OpenFile(
- what,
- os.O_WRONLY|os.O_TRUNC|os.O_CREATE,
- os.FileMode(0666),
- )
- dummy := func() {}
- if err != nil {
- return dummy, err
- }
- flock := unix.Flock_t{
- Type: unix.F_WRLCK,
- Whence: io.SeekStart,
- }
- if err = unix.FcntlFlock(fd.Fd(), unix.F_SETLKW, &flock); err != nil {
- fd.Close()
- return dummy, err
- }
- return func() {
- flock.Type = unix.F_UNLCK
- unix.FcntlFlock(fd.Fd(), unix.F_SETLK, &flock)
- fd.Close()
- }, nil
-}