uterm: vt: register input-cb for all VTs

This modifies the generic VT layer to register input-cbs for all VT types
and dispatch the event to the correct handler.
This will allow us to handle VT-switches for real VTs ourself instead of
relying on VT input.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

diff --git a/src/uterm_vt.c b/src/uterm_vt.c
index 8a15cd8..6509578 100644 (file)
--- a/src/uterm_vt.c
+++ b/src/uterm_vt.c
@@ -45,6 +45,7 @@
 #include "eloop.h"
 #include "log.h"
 #include "shl_dlist.h"
+#include "shl_misc.h"
 #include "uterm.h"
 
 #define LOG_SUBSYSTEM "vt"
@@ -492,23 +493,50 @@ static int fake_deactivate(struct uterm_vt *vt)
        return 0;
 }
 
+static void fake_input(struct uterm_vt *vt, struct uterm_input_event *ev)
+{
+       if (SHL_HAS_BITS(ev->mods, SHL_CONTROL_MASK | SHL_LOGO_MASK) &&
+           ev->keysym == XKB_KEY_F12) {
+               if (vt->active) {
+                       log_debug("deactivating fake VT due to user input");
+                       vt_call(vt, UTERM_VT_DEACTIVATE);
+               } else {
+                       log_debug("activating fake VT due to user input");
+                       vt_call(vt, UTERM_VT_ACTIVATE);
+               }
+       }
+}
+
+/*
+ * Generic VT handling layer
+ * VTs are a historical concept. Technically, they actually are a VT102
+ * compatible terminal emulator, but with the invention of X11 and other
+ * graphics servers, VTs were mainly used to control which application is
+ * currently active.
+ * If an application is "active" it is allowed to read keyboard/mouse/etc input
+ * and access the output devices (like displays/monitors). If an application is
+ * not active (that is, inactive) it should not access these devices at all and
+ * leave them for other VTs so they can access them.
+ *
+ * The kernel VTs have a horrible API and thus should be avoided whenever
+ * possible. We provide a layer for this VT as "real_*" VTs here. If those are
+ * not available, we also provide a layer for "fake_*" VTs. See their
+ * description for more information.
+ *
+ * If you allocate a new VT with this API, it automatically chooses the right
+ * implementation for you. So you are notified whenever your VT becomes active
+ * and when it becomes inactive. You do not have to care for any other VT
+ * handling.
+ */
+
 static void vt_input(struct uterm_input *input,
                     struct uterm_input_event *ev,
                     void *data)
 {
        struct uterm_vt *vt = data;
 
-       if (UTERM_INPUT_HAS_MODS(ev, UTERM_LOGO_MASK | UTERM_CONTROL_MASK)) {
-               if (ev->keysym == XKB_KEY_F12) {
-                       if (vt->active) {
-                               log_debug("deactivating fake VT due to user input");
-                               vt_call(vt, UTERM_VT_DEACTIVATE);
-                       } else {
-                               log_debug("activating fake VT due to user input");
-                               vt_call(vt, UTERM_VT_ACTIVATE);
-                       }
-               }
-       }
+       if (vt->mode == UTERM_VT_FAKE)
+               fake_input(vt, ev);
 }
 
 static void vt_sigusr1(struct ev_eloop *eloop, struct signalfd_siginfo *info,
@@ -553,6 +581,7 @@ int uterm_vt_allocate(struct uterm_vt_master *vtm,
        vt->vtm = vtm;
        vt->cb = cb;
        vt->data = data;
+       vt->input = input;
 
        vt->real_fd = -1;
        vt->real_num = -1;
@@ -566,27 +595,27 @@ int uterm_vt_allocate(struct uterm_vt_master *vtm,
        if (ret)
                goto err_sig1;
 
+       ret = uterm_input_register_cb(vt->input, vt_input, vt);
+       if (ret)
+               goto err_sig2;
+
        if (!strcmp(seat, "seat0") && vtm->vt_support) {
                vt->mode = UTERM_VT_REAL;
                ret = real_open(vt, vt_for_seat0);
                if (ret)
-                       goto err_sig2;
+                       goto err_input;
        } else {
                vt->mode = UTERM_VT_FAKE;
-               vt->input = input;
-
-               ret = uterm_input_register_cb(vt->input, vt_input, vt);
-               if (ret)
-                       goto err_sig2;
-
-               uterm_input_ref(vt->input);
-               uterm_input_wake_up(vt->input);
        }
 
+       uterm_input_ref(vt->input);
+       uterm_input_wake_up(vt->input);
        shl_dlist_link(&vtm->vts, &vt->list);
        *out = vt;
        return 0;
 
+err_input:
+       uterm_input_unregister_cb(vt->input, vt_input, vt);
 err_sig2:
        ev_eloop_unregister_signal_cb(vtm->eloop, SIGUSR2, vt_sigusr2, vt);
 err_sig1: