system: move system access packages

These packages loosely belong in the "system" package and "system" provides high level wrappers for all of them.

Signed-off-by: Ophestra <cat@gensokyo.uk>

sandbox/wl/conn.go

@@ -1,121 +0,0 @@
-// Package wl implements Wayland security_context_v1 protocol.
-package wl
-
-import (
-	"errors"
-	"net"
-	"os"
-	"runtime"
-	"sync"
-	"syscall"
-)
-
-type Conn struct {
-	conn *net.UnixConn
-
-	done     chan struct{}
-	doneOnce sync.Once
-
-	mu sync.Mutex
-}
-
-// Attach connects Conn to a wayland socket.
-func (c *Conn) Attach(p string) (err error) {
-	c.mu.Lock()
-	defer c.mu.Unlock()
-
-	if c.conn != nil {
-		return errors.New("attached")
-	}
-
-	c.conn, err = net.DialUnix("unix", nil, &net.UnixAddr{Name: p, Net: "unix"})
-	return
-}
-
-// Close releases resources and closes the connection to the wayland compositor.
-func (c *Conn) Close() error {
-	c.mu.Lock()
-	defer c.mu.Unlock()
-
-	if c.done == nil {
-		return errors.New("no socket bound")
-	}
-
-	c.doneOnce.Do(func() {
-		c.done <- struct{}{}
-		<-c.done
-	})
-
-	// closed by wayland
-	runtime.SetFinalizer(c.conn, nil)
-	return nil
-}
-
-func (c *Conn) Bind(p, appID, instanceID string) (*os.File, error) {
-	c.mu.Lock()
-	defer c.mu.Unlock()
-
-	if c.conn == nil {
-		return nil, errors.New("not attached")
-	}
-	if c.done != nil {
-		return nil, errors.New("bound")
-	}
-
-	if rc, err := c.conn.SyscallConn(); err != nil {
-		// unreachable
-		return nil, err
-	} else {
-		c.done = make(chan struct{})
-		return bindRawConn(c.done, rc, p, appID, instanceID)
-	}
-}
-
-func bindRawConn(done chan struct{}, rc syscall.RawConn, p, appID, instanceID string) (*os.File, error) {
-	var syncPipe [2]*os.File
-
-	if r, w, err := os.Pipe(); err != nil {
-		return nil, err
-	} else {
-		syncPipe[0] = r
-		syncPipe[1] = w
-	}
-
-	setupDone := make(chan error, 1) // does not block with c.done
-
-	go func() {
-		if err := rc.Control(func(fd uintptr) {
-			// prevent runtime from closing the read end of sync fd
-			runtime.SetFinalizer(syncPipe[0], nil)
-
-			// allow the Bind method to return after setup
-			setupDone <- bind(fd, p, appID, instanceID, syncPipe[0].Fd())
-			close(setupDone)
-
-			// keep socket alive until done is requested
-			<-done
-			runtime.KeepAlive(syncPipe[1])
-		}); err != nil {
-			setupDone <- err
-		}
-
-		// notify Close that rc.Control has returned
-		close(done)
-	}()
-
-	// return write end of the pipe
-	return syncPipe[1], <-setupDone
-}
-
-func bind(fd uintptr, p, appID, instanceID string, syncFd uintptr) error {
-	// ensure p is available
-	if f, err := os.Create(p); err != nil {
-		return err
-	} else if err = f.Close(); err != nil {
-		return err
-	} else if err = os.Remove(p); err != nil {
-		return err
-	}
-
-	return bindWaylandFd(p, fd, appID, instanceID, syncFd)
-}