diff options
Diffstat (limited to 'vendor/github.com/containerd/console/console_linux.go')
-rw-r--r-- | vendor/github.com/containerd/console/console_linux.go | 255 |
1 files changed, 0 insertions, 255 deletions
diff --git a/vendor/github.com/containerd/console/console_linux.go b/vendor/github.com/containerd/console/console_linux.go deleted file mode 100644 index c96372929..000000000 --- a/vendor/github.com/containerd/console/console_linux.go +++ /dev/null @@ -1,255 +0,0 @@ -// +build linux - -package console - -import ( - "io" - "os" - "sync" - - "golang.org/x/sys/unix" -) - -const ( - maxEvents = 128 -) - -// Epoller manages multiple epoll consoles using edge-triggered epoll api so we -// dont have to deal with repeated wake-up of EPOLLER or EPOLLHUP. -// For more details, see: -// - https://github.com/systemd/systemd/pull/4262 -// - https://github.com/moby/moby/issues/27202 -// -// Example usage of Epoller and EpollConsole can be as follow: -// -// epoller, _ := NewEpoller() -// epollConsole, _ := epoller.Add(console) -// go epoller.Wait() -// var ( -// b bytes.Buffer -// wg sync.WaitGroup -// ) -// wg.Add(1) -// go func() { -// io.Copy(&b, epollConsole) -// wg.Done() -// }() -// // perform I/O on the console -// epollConsole.Shutdown(epoller.CloseConsole) -// wg.Wait() -// epollConsole.Close() -type Epoller struct { - efd int - mu sync.Mutex - fdMapping map[int]*EpollConsole -} - -// NewEpoller returns an instance of epoller with a valid epoll fd. -func NewEpoller() (*Epoller, error) { - efd, err := unix.EpollCreate1(unix.EPOLL_CLOEXEC) - if err != nil { - return nil, err - } - return &Epoller{ - efd: efd, - fdMapping: make(map[int]*EpollConsole), - }, nil -} - -// Add creates a epoll console based on the provided console. The console will -// be registered with EPOLLET (i.e. using edge-triggered notification) and its -// file descriptor will be set to non-blocking mode. After this, user should use -// the return console to perform I/O. -func (e *Epoller) Add(console Console) (*EpollConsole, error) { - sysfd := int(console.Fd()) - // Set sysfd to non-blocking mode - if err := unix.SetNonblock(sysfd, true); err != nil { - return nil, err - } - - ev := unix.EpollEvent{ - Events: unix.EPOLLIN | unix.EPOLLOUT | unix.EPOLLRDHUP | unix.EPOLLET, - Fd: int32(sysfd), - } - if err := unix.EpollCtl(e.efd, unix.EPOLL_CTL_ADD, sysfd, &ev); err != nil { - return nil, err - } - ef := &EpollConsole{ - Console: console, - sysfd: sysfd, - readc: sync.NewCond(&sync.Mutex{}), - writec: sync.NewCond(&sync.Mutex{}), - } - e.mu.Lock() - e.fdMapping[sysfd] = ef - e.mu.Unlock() - return ef, nil -} - -// Wait starts the loop to wait for its consoles' notifications and signal -// appropriate console that it can perform I/O. -func (e *Epoller) Wait() error { - events := make([]unix.EpollEvent, maxEvents) - for { - n, err := unix.EpollWait(e.efd, events, -1) - if err != nil { - // EINTR: The call was interrupted by a signal handler before either - // any of the requested events occurred or the timeout expired - if err == unix.EINTR { - continue - } - return err - } - for i := 0; i < n; i++ { - ev := &events[i] - // the console is ready to be read from - if ev.Events&(unix.EPOLLIN|unix.EPOLLHUP|unix.EPOLLERR) != 0 { - if epfile := e.getConsole(int(ev.Fd)); epfile != nil { - epfile.signalRead() - } - } - // the console is ready to be written to - if ev.Events&(unix.EPOLLOUT|unix.EPOLLHUP|unix.EPOLLERR) != 0 { - if epfile := e.getConsole(int(ev.Fd)); epfile != nil { - epfile.signalWrite() - } - } - } - } -} - -// Close unregister the console's file descriptor from epoll interface -func (e *Epoller) CloseConsole(fd int) error { - e.mu.Lock() - defer e.mu.Unlock() - delete(e.fdMapping, fd) - return unix.EpollCtl(e.efd, unix.EPOLL_CTL_DEL, fd, &unix.EpollEvent{}) -} - -func (e *Epoller) getConsole(sysfd int) *EpollConsole { - e.mu.Lock() - f := e.fdMapping[sysfd] - e.mu.Unlock() - return f -} - -// Close the epoll fd -func (e *Epoller) Close() error { - return unix.Close(e.efd) -} - -// EpollConsole acts like a console but register its file descriptor with a -// epoll fd and uses epoll API to perform I/O. -type EpollConsole struct { - Console - readc *sync.Cond - writec *sync.Cond - sysfd int - closed bool -} - -// Read reads up to len(p) bytes into p. It returns the number of bytes read -// (0 <= n <= len(p)) and any error encountered. -// -// If the console's read returns EAGAIN or EIO, we assumes that its a -// temporary error because the other side went away and wait for the signal -// generated by epoll event to continue. -func (ec *EpollConsole) Read(p []byte) (n int, err error) { - var read int - ec.readc.L.Lock() - defer ec.readc.L.Unlock() - for { - read, err = ec.Console.Read(p[n:]) - n += read - if err != nil { - var hangup bool - if perr, ok := err.(*os.PathError); ok { - hangup = (perr.Err == unix.EAGAIN || perr.Err == unix.EIO) - } else { - hangup = (err == unix.EAGAIN || err == unix.EIO) - } - // if the other end disappear, assume this is temporary and wait for the - // signal to continue again. Unless we didnt read anything and the - // console is already marked as closed then we should exit - if hangup && !(n == 0 && len(p) > 0 && ec.closed) { - ec.readc.Wait() - continue - } - } - break - } - // if we didnt read anything then return io.EOF to end gracefully - if n == 0 && len(p) > 0 && err == nil { - err = io.EOF - } - // signal for others that we finished the read - ec.readc.Signal() - return n, err -} - -// Writes len(p) bytes from p to the console. It returns the number of bytes -// written from p (0 <= n <= len(p)) and any error encountered that caused -// the write to stop early. -// -// If writes to the console returns EAGAIN or EIO, we assumes that its a -// temporary error because the other side went away and wait for the signal -// generated by epoll event to continue. -func (ec *EpollConsole) Write(p []byte) (n int, err error) { - var written int - ec.writec.L.Lock() - defer ec.writec.L.Unlock() - for { - written, err = ec.Console.Write(p[n:]) - n += written - if err != nil { - var hangup bool - if perr, ok := err.(*os.PathError); ok { - hangup = (perr.Err == unix.EAGAIN || perr.Err == unix.EIO) - } else { - hangup = (err == unix.EAGAIN || err == unix.EIO) - } - // if the other end disappear, assume this is temporary and wait for the - // signal to continue again. - if hangup { - ec.writec.Wait() - continue - } - } - // unrecoverable error, break the loop and return the error - break - } - if n < len(p) && err == nil { - err = io.ErrShortWrite - } - // signal for others that we finished the write - ec.writec.Signal() - return n, err -} - -// Close closed the file descriptor and signal call waiters for this fd. -// It accepts a callback which will be called with the console's fd. The -// callback typically will be used to do further cleanup such as unregister the -// console's fd from the epoll interface. -// User should call Shutdown and wait for all I/O operation to be finished -// before closing the console. -func (ec *EpollConsole) Shutdown(close func(int) error) error { - ec.readc.L.Lock() - defer ec.readc.L.Unlock() - ec.writec.L.Lock() - defer ec.writec.L.Unlock() - - ec.readc.Broadcast() - ec.writec.Broadcast() - ec.closed = true - return close(ec.sysfd) -} - -// signalRead signals that the console is readable. -func (ec *EpollConsole) signalRead() { - ec.readc.Signal() -} - -// signalWrite signals that the console is writable. -func (ec *EpollConsole) signalWrite() { - ec.writec.Signal() -} |