From d6a83fe336230d60dcb166b9f9ffabe451404c5a Mon Sep 17 00:00:00 2001
From: Simon Tatham <anakin@pobox.com>
Date: Wed, 26 Jan 2022 20:02:15 +0000
Subject: [PATCH] Unix Pageant: ability to build without GTK.

Unix Pageant is in a tricky position as a hybrid CLI/GUI application.
It has uses even in a purely CLI environment, but it won't build
without libgtk-3-dev and friends.

The solution, of course - enabled by the migration to cmake - is to
allow it to build without GTK, leaving out just the GTK askpass
functionality. That way you can still use it in any of its CLI modes,
either as a non-graphical SSH agent or as a client for an agent
elsewhere.

(You can still even use it in X lifetime mode, because its connection
to the X server is done using PuTTY's built-in X authentication and
connection setup code. It's only putting up the password prompt window
that you lose in this configuration - so you're still fine as long as
you don't try to add any encrypted keys.)
---
 unix/CMakeLists.txt | 37 +++++++++++++++++++++++--------------
 unix/noaskpass.c    | 19 +++++++++++++++++++
 2 files changed, 42 insertions(+), 14 deletions(-)
 create mode 100644 unix/noaskpass.c

diff --git a/unix/CMakeLists.txt b/unix/CMakeLists.txt
index 342ca14f..6bb275d9 100644
--- a/unix/CMakeLists.txt
+++ b/unix/CMakeLists.txt
@@ -130,20 +130,6 @@ if(GTK_FOUND)
     window.c unifont.c dialog.c config-gtk.c gtk-common.c config-unix.c unicode.c printing.c)
   add_dependencies(guiterminal generated_licence_h) # dialog.c uses licence.h
 
-  add_executable(pageant
-    pageant.c
-    ${CMAKE_SOURCE_DIR}/stubs/nogss.c
-    askpass.c
-    x11.c
-    noise.c
-    ${CMAKE_SOURCE_DIR}/ssh/x11fwd.c
-    ${CMAKE_SOURCE_DIR}/proxy/nosshproxy.c)
-  be_list(pageant Pageant)
-  target_link_libraries(pageant
-    eventloop console agent settings network crypto utils
-    ${GTK_LIBRARIES})
-  installed_program(pageant)
-
   add_executable(pterm
     pterm.c
     main-gtk-simple.c
@@ -206,3 +192,26 @@ if(GTK_FOUND)
     guiterminal eventloop otherbackends settings network charset utils
     ${GTK_LIBRARIES} ${X11_LIBRARIES})
 endif()
+
+# Pageant is built whether we have GTK or not; in its absence we
+# degrade to a version that doesn't provide the GTK askpass.
+if(GTK_FOUND)
+  set(pageant_conditional_sources askpass.c)
+  set(pageant_libs ${GTK_LIBRARIES})
+else()
+  set(pageant_conditional_sources noaskpass.c no-gtk.c)
+  set(pageant_libs)
+endif()
+add_executable(pageant
+  pageant.c
+  ${CMAKE_SOURCE_DIR}/stubs/nogss.c
+  x11.c
+  noise.c
+  ${CMAKE_SOURCE_DIR}/ssh/x11fwd.c
+  ${CMAKE_SOURCE_DIR}/proxy/nosshproxy.c
+  ${pageant_conditional_sources})
+be_list(pageant Pageant)
+target_link_libraries(pageant
+  eventloop console agent settings network crypto utils
+  ${pageant_libs})
+installed_program(pageant)
diff --git a/unix/noaskpass.c b/unix/noaskpass.c
new file mode 100644
index 00000000..3d77b51c
--- /dev/null
+++ b/unix/noaskpass.c
@@ -0,0 +1,19 @@
+/*
+ * GTK implementation of a GUI password/passphrase prompt.
+ */
+
+#include "putty.h"
+
+void random_add_noise(NoiseSourceId source, const void *noise, int length)
+{
+    /* We have no keypress_prng here, so no need to implement this */
+}
+
+const bool buildinfo_gtk_relevant = false;
+
+char *gtk_askpass_main(const char *display, const char *wintitle,
+                       const char *prompt, bool *success)
+{
+    *success = false;
+    return dupstr("this Pageant was built without GTK");
+}