From b2e718f5a7b18db2f9991876f3d0886c8de4e00c Mon Sep 17 00:00:00 2001
From: Tin Lai <oscar@tinyiu.com>
Date: Tue, 6 Feb 2024 17:19:00 +1000
Subject: [PATCH] add text to avoid empty input for workaround

For the `input` workaround, we add a space key event to input some text
before pressing the enter key. This avoid the error that happens due to
gtk preventing empty input.

Signed-off-by: Tin Lai <oscar@tinyiu.com>
---
 howdy/src/pam/enter_device.cc | 25 +++++++++++++++++++++++++
 howdy/src/pam/enter_device.hh |  1 +
 howdy/src/pam/main.cc         |  4 ++++
 3 files changed, 30 insertions(+)

diff --git a/howdy/src/pam/enter_device.cc b/howdy/src/pam/enter_device.cc
index 0114d8d7..9f47e3db 100644
--- a/howdy/src/pam/enter_device.cc
+++ b/howdy/src/pam/enter_device.cc
@@ -11,6 +11,7 @@ EnterDevice::EnterDevice()
 
   libevdev_set_name(dev_ptr, "enter device");
   libevdev_enable_event_type(dev_ptr, EV_KEY);
+  libevdev_enable_event_code(dev_ptr, EV_KEY, KEY_SPACE, nullptr);
   libevdev_enable_event_code(dev_ptr, EV_KEY, KEY_ENTER, nullptr);
 
   int err;
@@ -24,6 +25,30 @@ EnterDevice::EnterDevice()
   raw_uinput_device.reset(uinput_dev_ptr);
 };
 
+void EnterDevice::send_space_press() const {
+  auto *uinput_dev_ptr = raw_uinput_device.get();
+
+  int err;
+  if ((err = libevdev_uinput_write_event(uinput_dev_ptr, EV_KEY, KEY_SPACE,
+                                         1)) != 0) {
+    throw std::runtime_error(std::string("Failed to write event: ") +
+                             strerror(-err));
+  }
+
+  if ((err = libevdev_uinput_write_event(uinput_dev_ptr, EV_KEY, KEY_SPACE,
+                                         0)) != 0) {
+    throw std::runtime_error(std::string("Failed to write event: ") +
+                             strerror(-err));
+  }
+
+  if ((err = libevdev_uinput_write_event(uinput_dev_ptr, EV_SYN, SYN_REPORT,
+                                         0)) != 0)
+  {
+    throw std::runtime_error(std::string("Failed to write event: ") +
+                             strerror(-err));
+  };
+}
+
 void EnterDevice::send_enter_press() const {
   auto *uinput_dev_ptr = raw_uinput_device.get();
 
diff --git a/howdy/src/pam/enter_device.hh b/howdy/src/pam/enter_device.hh
index acdadd15..372c1ac2 100644
--- a/howdy/src/pam/enter_device.hh
+++ b/howdy/src/pam/enter_device.hh
@@ -12,6 +12,7 @@ class EnterDevice {
 
 public:
   EnterDevice();
+  void send_space_press() const;
   void send_enter_press() const;
   ~EnterDevice() = default;
 };
diff --git a/howdy/src/pam/main.cc b/howdy/src/pam/main.cc
index d1b8e347..464b388e 100644
--- a/howdy/src/pam/main.cc
+++ b/howdy/src/pam/main.cc
@@ -409,6 +409,10 @@ auto identify(pam_handle_t *pamh, int flags, int argc, const char **argv,
           enter_device.send_enter_press();
         }
 
+        // try it one more time with an non-empty input field
+        enter_device.send_space_press();
+        enter_device.send_enter_press();
+
         if (retries == MAX_RETRIES) {
           syslog(LOG_WARNING,
                  "Failed to send enter input before the retries limit");