Resolves: #2050996, error on login when using ksh as the default shell

which.spec

@@ -1,7 +1,7 @@
 Summary: Displays where a particular program in your path is located
 Name: which
 Version: 2.21
-Release: 27%{?dist}
+Release: 28%{?dist}
 License: GPLv3
 Source0: http://ftp.gnu.org/gnu/which/%{name}-%{version}.tar.gz
 Source1: which2.sh
@@ -40,6 +40,9 @@ rm -f $RPM_BUILD_ROOT%{_infodir}/dir
 %{_mandir}/man1/which.1*
 
 %changelog
+* Fri Apr 15 2022 Than Ngo <than@redhat.com> - 2.21-28
+- Resolves: #2050996, error on login when using ksh as the default shell
+
 * Tue Aug 10 2021 Mohan Boddu <mboddu@redhat.com> - 2.21-27
 - Rebuilt for IMA sigs, glibc 2.34, aarch64 flags
   Related: rhbz#1991688

which2.sh

@@ -1,18 +1,27 @@
 # shellcheck shell=sh
 # Initialization script for bash, sh, mksh and ksh
 
-which_declare="declare -f"
-which_opt="-f"
-which_shell="$(cat /proc/$$/comm)"
+case "$(basename $(readlink /proc/$$/exe))" in
+*ksh*)
+    which_declare=""
+    which_opt=""
+    ;;
+zsh)
+    which_declare="typeset -f"
+    which_opt=""
+    ;;
+bash|sh)
+    which_declare="declare -f"
+    which_opt="-f"
+    ;;
+*)
+    which_declare=""
+    which_opt=""
+    ;;
+esac
 
-if [ "$which_shell" = "ksh" ] || [ "$which_shell" = "mksh" ] || [ "$which_shell" = "zsh" ] ; then
-  which_declare="typeset -f"
-  which_opt=""
-fi
- 
-which ()
-{
-(alias; eval ${which_declare}) | /usr/bin/which --tty-only --read-alias --read-functions --show-tilde --show-dot "$@"
+function which {
+    (alias; eval ${which_declare}) | /usr/bin/which --tty-only --read-alias --read-functions --show-tilde --show-dot $@
 }
 
 export which_declare