From 505e5c6665e68fac58d9f6c689cc0c1bea2a83bc Mon Sep 17 00:00:00 2001
From: Fabian Vogt <fabian@ritter-vogt.de>
Date: Fri, 4 Aug 2023 23:34:08 +0200
Subject: [PATCH] Redesign login shell use in session scripts

Avoid the re-import of variables into sh by using the user's login shell
to invoke the session.

For the wayland-session script it's straightforward: Just exec the session
command directly within the login shell.

For the Xsession script it's a bit more complex: The login shell environment
has to be loaded first, then the xprofile files, so that they can overwrite
the login shell environment. To achieve this, the script runs in two stages:
The first uses the login shell to exec the second stage, which then reads
xprofile and execs the session.
---
 data/scripts/Xsession        | 69 ++++++++++++++++++------------------
 data/scripts/wayland-session | 35 +++++-------------
 2 files changed, 43 insertions(+), 61 deletions(-)

diff --git a/data/scripts/Xsession b/data/scripts/Xsession
index a971d40..235a671 100755
--- a/data/scripts/Xsession
+++ b/data/scripts/Xsession
@@ -5,39 +5,34 @@
 # This file is extracted from kde-workspace (kdm/kfrontend/genkdmconf.c)
 # Copyright (C) 2001-2005 Oswald Buddenhagen <ossi@kde.org>
 
-# Note that the respective logout scripts are not sourced.
-case $SHELL in
-  */bash)
-    [ -z "$BASH" ] && exec $SHELL --login $0 "$@"
-    shopt -q login_shell || exec $SHELL --login $0 "$@"
-    set +o posix
-    ;;
-  */zsh)
-    [ -z "$ZSH_NAME" ] && exec $SHELL --login $0 "$@"
-    [[ -o login ]] || exec $SHELL --login $0 "$@"
-    emulate -R sh
-    ;;
-  */csh|*/tcsh)
-    # [t]cshrc is always sourced automatically.
-    # Note that sourcing csh.login after .cshrc is non-standard.
-    xsess_tmp=`mktemp /tmp/xsess-env-XXXXXX`
-    $SHELL -c "if (-f /etc/csh.login) source /etc/csh.login; if (-f ~/.login) source ~/.login; /bin/sh -c 'export -p' >! $xsess_tmp"
-    . $xsess_tmp
-    rm -f $xsess_tmp
-    ;;
-  */fish)
-    [ -f /etc/profile ] && . /etc/profile
-    [ -f $HOME/.profile ] && . $HOME/.profile
-    xsess_tmp=`mktemp /tmp/xsess-env-XXXXXX`
-    $SHELL --login -c "/bin/sh -c 'export -p' > $xsess_tmp"
-    . $xsess_tmp
-    rm -f $xsess_tmp
-    ;;
-  *) # Plain sh, ksh, and anything we do not know.
-    [ -f /etc/profile ] && . /etc/profile
-    [ -f $HOME/.profile ] && . $HOME/.profile
-    ;;
-esac
+# Import the login environment for some shells by starting them as login shell
+# and executing this script. Inside, SDDM_XSESSION_PROFILE_READ will be set and
+# it continues below.
+if [ -z "$SDDM_XSESSION_PROFILE_READ" ]; then
+  export SDDM_XSESSION_PROFILE_READ=1
+
+  case $SHELL in
+    */bash|*/zsh)
+      exec $SHELL --login -c 'exec "$@"' - $0 "$@"
+      ;;
+    */csh|*/tcsh)
+      exec $SHELL -c 'if (-f /etc/csh.login) source /etc/csh.login; if (-f ~/.login) source ~/.login; exec $argv' $0 "$@"
+      ;;
+    */fish)
+      [ -f /etc/profile ] && . /etc/profile
+      [ -f $HOME/.profile ] && . $HOME/.profile
+      exec $SHELL --login -c 'exec $argv' $0 "$@"
+      ;;
+    *) # Plain sh, ksh, and anything we do not know.
+      [ -f /etc/profile ] && . /etc/profile
+      [ -f $HOME/.profile ] && . $HOME/.profile
+      exec $0 "$@"
+      ;;
+  esac
+
+  exit 1
+fi
+unset SDDM_XSESSION_PROFILE_READ
 
 [ -f /etc/xprofile ] && . /etc/xprofile
 [ -f /usr/local/etc/xprofile ] && . /usr/local/etc/xprofile
@@ -89,6 +84,10 @@ fi
 
 if [ -z "$*" ]; then
     exec xmessage -center -buttons OK:0 -default OK "Sorry, $DESKTOP_SESSION is no valid session."
-else
-    exec $@
+    exit 1
 fi
+
+# Note: This script is called with the whole session commandline as a single first argument.
+# To run it properly, word splitting has to be performed by the shell, i.e. $@ or $0 without quotes.
+exec $@
+exit 1
diff --git a/data/scripts/wayland-session b/data/scripts/wayland-session
index bbeb7ce..3ed44b0 100755
--- a/data/scripts/wayland-session
+++ b/data/scripts/wayland-session
@@ -5,45 +5,28 @@
 # This file is extracted from kde-workspace (kdm/kfrontend/genkdmconf.c)
 # Copyright (C) 2001-2005 Oswald Buddenhagen <ossi@kde.org>
 
-# Note that the respective logout scripts are not sourced.
+# Note: This script is called with the whole session commandline as a single first argument.
+# To run it properly, word splitting has to be performed by the shell, i.e. $@ or $0 without quotes.
 
-# Backup the user shell setting into SDDM specific variable
-SDDM_USER_SHELL=$SHELL
+# Note that the respective logout scripts are not sourced.
 
 case $SHELL in
-  */bash)
-    [ -z "$BASH" ] && exec $SHELL --login $0 "$@"
-    shopt -q login_shell || exec $SHELL --login $0 "$@"
-    set +o posix
-    ;;
-  */zsh)
-    [ -z "$ZSH_NAME" ] && exec $SHELL --login $0 "$@"
-    [[ -o login ]] || exec $SHELL --login $0 "$@"
-    emulate -R sh
+  */bash|*/zsh)
+    exec $SHELL --login -c 'exec "$@"' - $@
     ;;
   */csh|*/tcsh)
-    # [t]cshrc is always sourced automatically.
-    # Note that sourcing csh.login after .cshrc is non-standard.
-    wlsess_tmp=`mktemp /tmp/wlsess-env-XXXXXX`
-    $SHELL -c "if (-f /etc/csh.login) source /etc/csh.login; if (-f ~/.login) source ~/.login; /bin/sh -c 'export -p' >! $wlsess_tmp"
-    . $wlsess_tmp
-    rm -f $wlsess_tmp
+    exec $SHELL -c 'if (-f /etc/csh.login) source /etc/csh.login; if (-f ~/.login) source ~/.login; exec $argv' $@
     ;;
   */fish)
     [ -f /etc/profile ] && . /etc/profile
     [ -f $HOME/.profile ] && . $HOME/.profile
-    xsess_tmp=`mktemp /tmp/xsess-env-XXXXXX`
-    $SHELL --login -c "/bin/sh -c 'export -p' > $xsess_tmp"
-    . $xsess_tmp
-    rm -f $xsess_tmp
+    exec $SHELL --login -c 'exec $argv' $@
     ;;
   *) # Plain sh, ksh, and anything we do not know.
     [ -f /etc/profile ] && . /etc/profile
     [ -f $HOME/.profile ] && . $HOME/.profile
+    exec $@
     ;;
 esac
 
-# Restore user shell setting that may have been clobbered by setting environment
-export SHELL=$SDDM_USER_SHELL
-
-exec $@
+exit 1
-- 
2.44.0