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/wayland.go

@@ -0,0 +1,48 @@
+// Package wayland implements Wayland security_context_v1 protocol.
+package wayland
+
+//go:generate sh -c "wayland-scanner client-header `pkg-config --variable=datarootdir wayland-protocols`/wayland-protocols/staging/security-context/security-context-v1.xml security-context-v1-protocol.h"
+//go:generate sh -c "wayland-scanner private-code `pkg-config --variable=datarootdir wayland-protocols`/wayland-protocols/staging/security-context/security-context-v1.xml security-context-v1-protocol.c"
+
+/*
+#cgo linux pkg-config: --static wayland-client
+#cgo freebsd openbsd LDFLAGS: -lwayland-client
+
+#include "wayland-client-helper.h"
+*/
+import "C"
+import (
+	"errors"
+	"strings"
+	"syscall"
+)
+
+const (
+	// Display contains the name of the server socket
+	// (https://gitlab.freedesktop.org/wayland/wayland/-/blob/1.23.1/src/wayland-client.c#L1147)
+	// which is concatenated with XDG_RUNTIME_DIR
+	// (https://gitlab.freedesktop.org/wayland/wayland/-/blob/1.23.1/src/wayland-client.c#L1171)
+	// or used as-is if absolute
+	// (https://gitlab.freedesktop.org/wayland/wayland/-/blob/1.23.1/src/wayland-client.c#L1176).
+	Display = "WAYLAND_DISPLAY"
+
+	// FallbackName is used as the wayland socket name if WAYLAND_DISPLAY is unset
+	// (https://gitlab.freedesktop.org/wayland/wayland/-/blob/1.23.1/src/wayland-client.c#L1149).
+	FallbackName = "wayland-0"
+)
+
+var resErr = [...]error{
+	0: nil,
+	1: errors.New("wl_display_connect_to_fd() failed"),
+	2: errors.New("wp_security_context_v1 not available"),
+}
+
+func bindWaylandFd(socketPath string, fd uintptr, appID, instanceID string, syncFd uintptr) error {
+	if hasNull(appID) || hasNull(instanceID) {
+		return syscall.EINVAL
+	}
+	res := C.hakurei_bind_wayland_fd(C.CString(socketPath), C.int(fd), C.CString(appID), C.CString(instanceID), C.int(syncFd))
+	return resErr[int32(res)]
+}
+
+func hasNull(s string) bool { return strings.IndexByte(s, 0) > -1 }