internal/system: relocate from system

These packages are highly specific to hakurei and are difficult to use safely from other pieces of code.

Their exported symbols are made available until v0.4.0 where they will be removed for #24.

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

internal/system/wayland.go

@@ -0,0 +1,90 @@
+package system
+
+import (
+	"errors"
+	"fmt"
+	"os"
+
+	"hakurei.app/container/check"
+	"hakurei.app/hst"
+	"hakurei.app/internal/system/acl"
+	"hakurei.app/internal/system/wayland"
+)
+
+type waylandConn interface {
+	Attach(p string) (err error)
+	Bind(pathname, appID, instanceID string) (*os.File, error)
+	Close() error
+}
+
+// Wayland maintains a wayland socket with security-context-v1 attached via [wayland].
+// The socket stops accepting connections once the pipe referred to by sync is closed.
+// The socket is pathname only and is destroyed on revert.
+func (sys *I) Wayland(dst, src *check.Absolute, appID, instanceID string) *I {
+	sys.ops = append(sys.ops, &waylandOp{nil,
+		dst.String(), src.String(),
+		appID, instanceID,
+		new(wayland.Conn)})
+	return sys
+}
+
+// waylandOp implements [I.Wayland].
+type waylandOp struct {
+	sync              *os.File
+	dst, src          string
+	appID, instanceID string
+
+	conn waylandConn
+}
+
+func (w *waylandOp) Type() hst.Enablement { return Process }
+
+func (w *waylandOp) apply(sys *I) error {
+	if err := w.conn.Attach(w.src); err != nil {
+		return newOpError("wayland", err, false)
+	} else {
+		sys.msg.Verbosef("wayland attached on %q", w.src)
+	}
+
+	if sp, err := w.conn.Bind(w.dst, w.appID, w.instanceID); err != nil {
+		return newOpError("wayland", err, false)
+	} else {
+		w.sync = sp
+		sys.msg.Verbosef("wayland listening on %q", w.dst)
+		if err = sys.chmod(w.dst, 0); err != nil {
+			return newOpError("wayland", err, false)
+		}
+		return newOpError("wayland", sys.aclUpdate(w.dst, sys.uid, acl.Read, acl.Write, acl.Execute), false)
+	}
+}
+
+func (w *waylandOp) revert(sys *I, _ *Criteria) error {
+	var (
+		hangupErr error
+		closeErr  error
+		removeErr error
+	)
+
+	sys.msg.Verbosef("detaching from wayland on %q", w.src)
+	if w.sync != nil {
+		hangupErr = w.sync.Close()
+	}
+	closeErr = w.conn.Close()
+
+	sys.msg.Verbosef("removing wayland socket on %q", w.dst)
+	if err := sys.remove(w.dst); err != nil && !errors.Is(err, os.ErrNotExist) {
+		removeErr = err
+	}
+
+	return newOpError("wayland", errors.Join(hangupErr, closeErr, removeErr), true)
+}
+
+func (w *waylandOp) Is(o Op) bool {
+	target, ok := o.(*waylandOp)
+	return ok && w != nil && target != nil &&
+		w.dst == target.dst && w.src == target.src &&
+		w.appID == target.appID && w.instanceID == target.instanceID
+}
+
+func (w *waylandOp) Path() string   { return w.dst }
+func (w *waylandOp) String() string { return fmt.Sprintf("wayland socket at %q", w.dst) }