terminal: add evdev elements to idev

The evdev-element provides linux evdev interfaces as idev-elements. This
way, all real input hardware devices on linux can be used with the idev
interface.

We use libevdev to interface with the kernel. It's a simple wrapper
library around the kernel evdev API that takes care to resync devices
after kernel-queue overflows, which is a rather non-trivial task.
Furthermore, it's a well tested interface used by all other major input
users (Xorg, weston, libinput, ...).
Last but not least, it provides nice keycode to keyname lookup tables (and
vice versa), which is really nice for debugging input problems.

1 files changed, 48 insertions, 0 deletions

diff --git a/src/libsystemd-terminal/idev.c b/src/libsystemd-terminal/idev.c
index 5e3080797..2316a6652 100644
--- a/src/libsystemd-terminal/idev.c
+++ b/src/libsystemd-terminal/idev.c
@@ -20,6 +20,8 @@
 ***/
 
 #include <inttypes.h>
+#include <libudev.h>
+#include <linux/input.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <systemd/sd-bus.h>
@@ -31,6 +33,7 @@
 #include "login-shared.h"
 #include "macro.h"
 #include "set.h"
+#include "udev-util.h"
 #include "util.h"
 
 static void element_open(idev_element *e);
@@ -522,6 +525,51 @@ void idev_session_disable(idev_session *s) {
         }
 }
 
+int idev_session_add_evdev(idev_session *s, struct udev_device *ud) {
+        idev_element *e;
+        dev_t devnum;
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(ud, -EINVAL);
+
+        devnum = udev_device_get_devnum(ud);
+        if (devnum == 0)
+                return 0;
+
+        e = idev_find_evdev(s, devnum);
+        if (e)
+                return 0;
+
+        r = idev_evdev_new(&e, s, ud);
+        if (r < 0)
+                return r;
+
+        r = session_add_element(s, e);
+        if (r != 0)
+                return r;
+
+        return 0;
+}
+
+int idev_session_remove_evdev(idev_session *s, struct udev_device *ud) {
+        idev_element *e;
+        dev_t devnum;
+
+        assert(s);
+        assert(ud);
+
+        devnum = udev_device_get_devnum(ud);
+        if (devnum == 0)
+                return 0;
+
+        e = idev_find_evdev(s, devnum);
+        if (!e)
+                return 0;
+
+        return session_remove_element(s, e);
+}
+
 /*
  * Contexts
  */