111 lines
2.1 KiB
Go
111 lines
2.1 KiB
Go
// SPDX-License-Identifier: MIT
|
|
//
|
|
// Copyright © 2020 Kent Gibson <warthog618@gmail.com>.
|
|
|
|
package gpiod
|
|
|
|
import (
|
|
"fmt"
|
|
"time"
|
|
|
|
"github.com/warthog618/gpiod/uapi"
|
|
"golang.org/x/sys/unix"
|
|
)
|
|
|
|
type infoWatcher struct {
|
|
epfd int
|
|
|
|
// the handler for detected events
|
|
ch InfoChangeHandler
|
|
|
|
// pipe to signal watcher to shutdown
|
|
donefds []int
|
|
|
|
// closed once watcher exits
|
|
doneCh chan struct{}
|
|
}
|
|
|
|
func newInfoWatcher(fd int, ch InfoChangeHandler) (iw *infoWatcher, err error) {
|
|
var epfd int
|
|
epfd, err = unix.EpollCreate1(unix.EPOLL_CLOEXEC)
|
|
if err != nil {
|
|
return
|
|
}
|
|
defer func() {
|
|
if err != nil {
|
|
unix.Close(epfd)
|
|
}
|
|
}()
|
|
p := []int{0, 0}
|
|
err = unix.Pipe2(p, unix.O_CLOEXEC)
|
|
if err != nil {
|
|
return
|
|
}
|
|
defer func() {
|
|
if err != nil {
|
|
unix.Close(p[0])
|
|
unix.Close(p[1])
|
|
}
|
|
}()
|
|
epv := unix.EpollEvent{Events: unix.EPOLLIN, Fd: int32(p[0])}
|
|
err = unix.EpollCtl(epfd, unix.EPOLL_CTL_ADD, int(p[0]), &epv)
|
|
if err != nil {
|
|
return
|
|
}
|
|
epv.Fd = int32(fd)
|
|
err = unix.EpollCtl(epfd, unix.EPOLL_CTL_ADD, fd, &epv)
|
|
if err != nil {
|
|
return
|
|
}
|
|
iw = &infoWatcher{
|
|
epfd: epfd,
|
|
ch: ch,
|
|
donefds: p,
|
|
doneCh: make(chan struct{}),
|
|
}
|
|
go iw.watch()
|
|
return
|
|
}
|
|
|
|
func (iw *infoWatcher) close() {
|
|
unix.Write(iw.donefds[1], []byte("bye"))
|
|
<-iw.doneCh
|
|
unix.Close(iw.donefds[0])
|
|
unix.Close(iw.donefds[1])
|
|
}
|
|
|
|
func (iw *infoWatcher) watch() {
|
|
epollEvents := make([]unix.EpollEvent, 2)
|
|
defer close(iw.doneCh)
|
|
for {
|
|
n, err := unix.EpollWait(iw.epfd, epollEvents[:], -1)
|
|
if err != nil {
|
|
if err == unix.EBADF || err == unix.EINVAL {
|
|
// fd closed so exit
|
|
return
|
|
}
|
|
if err == unix.EINTR {
|
|
continue
|
|
}
|
|
panic(fmt.Sprintf("EpollWait unexpected error: %v", err))
|
|
}
|
|
for i := 0; i < n; i++ {
|
|
ev := epollEvents[i]
|
|
fd := ev.Fd
|
|
if fd == int32(iw.donefds[0]) {
|
|
unix.Close(iw.epfd)
|
|
return
|
|
}
|
|
lic, err := uapi.ReadLineInfoChanged(uintptr(fd))
|
|
if err != nil {
|
|
continue
|
|
}
|
|
lice := LineInfoChangeEvent{
|
|
Info: newLineInfo(lic.Info),
|
|
Timestamp: time.Duration(lic.Timestamp),
|
|
Type: LineInfoChangeType(lic.Type),
|
|
}
|
|
iw.ch(lice)
|
|
}
|
|
}
|
|
}
|