1 files changed, 127 insertions, 0 deletions
diff --git a/pkgs/simple/pinentry-urxvt/default.nix b/pkgs/simple/pinentry-urxvt/default.nix
new file mode 100644
index 0000000..7363f26
--- /dev/null
+++ b/pkgs/simple/pinentry-urxvt/default.nix
@@ -0,0 +1,127 @@
+{ lib, pkgs, ... }@args:
+
+let
+  mylib = import ../../../lib/pure.nix {
+    inherit lib;
+  };
+
+  # config cannot be declared in the input attribute set because that would
+  # cause callPackage to inject the wrong config.  Instead, get it from ...
+  # via args.
+  config = args.config or {};
+
+  cfg = eval.config;
+
+  eval = lib.evalModules {
+    modules = lib.singleton {
+      _file = toString ./default.nix;
+      imports = lib.singleton config;
+      options = {
+        appName = lib.mkOption {
+          default = "pinentry-urxvt";
+          type = lib.types.str;
+        };
+        display = lib.mkOption {
+          default = null;
+          type = lib.types.nullOr lib.types.str;
+        };
+        xwud.className = lib.mkOption {
+          default = "PinentryUrxvtXwudFloat";
+          type = lib.types.str;
+        };
+      };
+    };
+  };
+
+
+in
+
+  # pinentry-urxvt - A mechanism for PIN entry utilizing rxvt-unicode
+  #
+  # This spawns a PIN entry terminal on top of a tinted screenshot of the
+  # current display's root window.  The display for spawning the terminal can
+  # be predefined, in which case both the current and the predefined display
+  # will show the screenshot.
+  #
+  # The purpose of the screenshot, aside from looking nice, is to prevent entry
+  # of the PIN into the wrong window, e.g. by accidentally moving the cursor
+  # while typing.  If necessary, the screenshot can be closed by sending 'q',
+  # 'Q', or ctrl-c while its focused.
+  #
+  pkgs.write "pinentry-urxvt" {
+    "/bin/pinentry".link = pkgs.writeDash "pinentry-urxvt-wrapper" ''
+      set -efu
+
+      trap cleanup EXIT
+
+      cleanup() {
+        ${pkgs.utillinux}/bin/kill -- $(${pkgs.coreutils}/bin/cat "$displayers")
+        rm "$displayers"
+        rm "$screenshot"
+      }
+
+      displayers=$(${pkgs.coreutils}/bin/mktemp -t pinentry-urxvt.$$.displayers.XXXXXXXX)
+      screenshot=$(${pkgs.coreutils}/bin/mktemp -t pinentry-urxvt.$$.screenshot.XXXXXXXX)
+
+      ${pkgs.xorg.xwd}/bin/xwd -root |
+      ${pkgs.imagemagick}/bin/convert xwd:- -fill \#424242 -colorize 80% xwd:"$screenshot"
+
+      display_screenshot() {
+        ${pkgs.exec "pinentry-urxvt.display_screenshot" {
+            filename = "${pkgs.xorg.xwud}/bin/xwud";
+            argv = [
+              cfg.xwud.className
+              "-noclick"
+            ];
+        }} < "$screenshot" &
+        wait_for_screenshot $! && echo $! >>"$displayers"
+      }
+
+      # Wait for the xwud window by trying to intercept the call to munmap().
+      # If it cannot be intercepted within 0.1s, assume that attaching strace
+      # wasn't fast enough or xwud doesn't call munmap() anymore.  In either
+      # case fall back to search the window by class name, assuming there can
+      # be only one per display.
+      wait_for_screenshot() {
+        if ! \
+          ${pkgs.coreutils}/bin/timeout 0.1 \
+          ${pkgs.strace}/bin/strace -p "$1" -e munmap 2>&1 |
+          read -r _
+        then
+          until ${pkgs.xdotool}/bin/xdotool search \
+                    --classname ${mylib.shell.escape cfg.xwud.className}
+          do
+            ${pkgs.coreutils}/bin/sleep 0.1
+          done
+        fi
+      }
+
+      display_screenshot
+
+      ${lib.optionalString (cfg.display != null) /* sh */ ''
+        if test "$DISPLAY" != ${mylib.shell.escape cfg.display}; then
+          export DISPLAY=${mylib.shell.escape cfg.display}
+          display_screenshot
+        fi
+      ''}
+
+      exec 3<&0 4>&1 5>&2
+      ${pkgs.rxvt_unicode}/bin/urxvt \
+        -name ${mylib.shell.escape cfg.appName} \
+        -e ${pkgs.writeDash "pinentry-urxvt-tty" ''
+          set -efu
+          exec 2>&5
+          TTY=$(${pkgs.coreutils}/bin/tty)
+          while read -r line <&3; do
+            case $line in
+              'OPTION ttyname='*)
+                echo "OPTION ttyname=$TTY"
+                ;;
+              *)
+                echo "$line"
+            esac
+          done | ${pkgs.pinentry.tty}/bin/pinentry-tty "$@" >&4
+        ''} \
+        "$@"
+    '';
+  }