gnome3.gnome-session: prevent crash when launching wayland sessions

gnome-session inherits GDMS PATH, which is at the moment non-functional. In X11
this didn't matter as the `Xsession` wrapper would populate the environment
beforehand. Wayland sessions doesn't source `Xesssion` (duh), so we patch
`bin/gnome-session` to use absolute paths for `grep` and `bash`.

In addition `bin/gnome-session` is a simple wrapper around
`libexec/gnome-session-binary` mostly responsible for sourcing the users profile
before launching the binary. This made our wrapping of `bin/gnome-session`
ineffective on wayland as the profile would reset the environment. Simply wrap
`libexec/gnome-session-binary` instead.

2 files changed, 24 insertions, 3 deletions

diff --git a/pkgs/desktops/gnome-3/core/gnome-session/default.nix b/pkgs/desktops/gnome-3/core/gnome-session/default.nix
index ceda3dfd56f..2f44a4e168d 100644
--- a/pkgs/desktops/gnome-3/core/gnome-session/default.nix
+++ b/pkgs/desktops/gnome-3/core/gnome-session/default.nix
@@ -1,6 +1,6 @@
 { fetchurl, stdenv, substituteAll, meson, ninja, pkgconfig, gnome3, glib, gtk, gsettings-desktop-schemas
 , gnome-desktop, dbus, json-glib, libICE, xmlto, docbook_xsl, docbook_xml_dtd_412, python3
-, libxslt, gettext, makeWrapper, systemd, xorg, epoxy }:
+, libxslt, gettext, makeWrapper, systemd, xorg, epoxy, gnugrep, bash }:
 
 stdenv.mkDerivation rec {
   name = "gnome-session-${version}";
@@ -16,6 +16,8 @@ stdenv.mkDerivation rec {
       src = ./fix-paths.patch;
       gsettings = "${glib.bin}/bin/gsettings";
       dbusLaunch = "${dbus.lib}/bin/dbus-launch";
+      grep = "${gnugrep}/bin/grep";
+      bash = "${bash}/bin/bash";
     })
   ];
 
@@ -37,8 +39,11 @@ stdenv.mkDerivation rec {
     patchShebangs meson_post_install.py
   '';
 
+  # `bin/gnome-session` will reset the environment when run in wayland, we
+  # therefor wrap `libexec/gnome-session-binary` instead which is the actual
+  # binary needing wrapping
   preFixup = ''
-    wrapProgram "$out/bin/gnome-session" \
+    wrapProgram "$out/libexec/gnome-session-binary" \
       --prefix GI_TYPELIB_PATH : "$GI_TYPELIB_PATH" \
       --suffix XDG_DATA_DIRS : "$out/share:$GSETTINGS_SCHEMAS_PATH" \
       --suffix XDG_DATA_DIRS : "${gnome3.gnome-shell}/share"\
diff --git a/pkgs/desktops/gnome-3/core/gnome-session/fix-paths.patch b/pkgs/desktops/gnome-3/core/gnome-session/fix-paths.patch
index c1b5ebe842f..fe4feaf7085 100644
--- a/pkgs/desktops/gnome-3/core/gnome-session/fix-paths.patch
+++ b/pkgs/desktops/gnome-3/core/gnome-session/fix-paths.patch
@@ -1,6 +1,22 @@
 --- a/gnome-session/gnome-session.in
 +++ b/gnome-session/gnome-session.in
-@@ -13,7 +13,7 @@ if [ "x$XDG_SESSION_TYPE" = "xwayland" ] &&
+@@ -3,11 +3,11 @@
+ if [ "x$XDG_SESSION_TYPE" = "xwayland" ] &&
+    [ "x$XDG_SESSION_CLASS" != "xgreeter" ] &&
+    [  -n "$SHELL" ] &&
+-   grep -q "$SHELL" /etc/shells &&
+-   ! (echo "$SHELL" | grep -q "false") &&
+-   ! (echo "$SHELL" | grep -q "nologin"); then
++   @grep@ -q "$SHELL" /etc/shells &&
++   ! (echo "$SHELL" | @grep@ -q "false") &&
++   ! (echo "$SHELL" | @grep@ -q "nologin"); then
+   if [ "$1" != '-l' ]; then
+-    exec bash -c "exec -l '$SHELL' -c '$0 -l $*'"
++    exec @bash@ -c "exec -l '$SHELL' -c '$0 -l $*'"
+   else
+     shift
+   fi
+@@ -13,7 +13,7 @@
    fi
  fi