Restore environment variables when becoming.

[profile.git] / opt / bin / become

diff --git a/opt/bin/become b/opt/bin/become
index abe1b85..4b1c0dc 100755 (executable)
--- a/opt/bin/become
+++ b/opt/bin/become
@@ -1,13 +1,135 @@
 #!/bin/bash
 
-user="$1"
+chdir=0
+kerberos=0
+x11=0
+while getopts ":kx" opt; do
+  case $opt in
+    c) chdir=1;;
+    k) kerberos=1;;
+    x) x11=1;;
+  esac
+done
+shift $((OPTIND-1))
+
+user="$1"; shift
 if [ -z "$user" ]; then
-  echo >&2 "Usage: become <user>"
+  echo >&2 "Usage: become [-c] [-k] [-x] <user>"
+  echo >&2 "Options: -c   Stay in current directory even if target user is not root."
+  echo >&2 "         -k   Delegate Kerberos credentials even if target user is not root."
+  echo >&2 "         -x   Delegate X11 cookie even if target user is not root."
   exit 1
 fi
 
-BECOME="$HOME/.become"
-profile="$BECOME/$user"
-[ -f "$profile" ] || profile="$BECOME/all"
+uid=$(PATH=/usr/xpg4/bin:/usr/bin id -u "$user" 2>/dev/null)
+if [ -z "$uid" ]; then
+  echo >&2 "Who is $user?"
+  exit 2
+fi
+
+if [ $uid = 0 ]; then
+  chdir=1
+  kerberos=1
+  x11=1
+fi
+
+PRINCIPAL=$(klist 2>/dev/null | sed -n 's/^Default principal: //p')
+if [ $x11 = 1 -a -n "$DISPLAY" -a "${DISPLAY##localhost:}" = "$DISPLAY" ]; then
+  COOKIE="$(xauth list $DISPLAY)"
+fi
+ignore_profile_user=0
+for candidate in "$HOME" "$PROFILE_HOME"; do
+  [ -n "$candidate" ] || continue
+  BECOME="$candidate/.become"
+  [ -d "$BECOME" ] || continue
+
+  # Script to run when becoming any user.
+  [ -z "$allusersprofile" ] && allusersprofile="$BECOME/all"
+  [ -f "$allusersprofile" ] || allusersprofile=
+
+  # Set $HOME/all sticky to ignore $PROFILE_HOME/$user.
+  if [ "$candidate" = "$HOME" ]; then
+    [ -k "$BECOME/all" ] && ignore_profile_user=1
+  else
+    [ $ignore_profile_user = 1 ] && continue
+  fi
+
+  # Script to run (after the one mentioned above) when becoming this user.
+  [ -z "$userprofile" ] && userprofile="$BECOME/$user"
+  [ -f "$userprofile" ] || userprofile=
+done
+
+# Preserve environment variables.
+ignore_environment_user=0
+for candidate in "$HOME" "$PROFILE_HOME"; do
+  [ -n "$candidate" ] || continue
+  BECOME="$candidate/.become/environment"
+  [ -d "$BECOME" ] || continue
+
+  # Script to run when becoming any user.
+  [ -z "$allusersenvironment" ] && allusersenvironment="$BECOME/all"
+  [ -f "$allusersenvironment" ] || allusersenvironment=
+
+  # Set $HOME/all sticky to ignore $PROFILE_HOME/$user.
+  if [ "$candidate" = "$HOME" ]; then
+    [ -k "$BECOME/all" ] && ignore_environment_user=1
+  else
+    [ $ignore_environment_user = 1 ] && continue
+  fi
+
+  # Environment variables to preserve when becomeing this user.
+  [ -z "$userenvironment" ] && userenvironment="$BECOME/$user"
+  [ -f "$userenvironment" ] || userenvironment=
+done
+
+file="${TMPDIR:-/tmp}/$USER.become.$user.$RANDOM.$$"
+umask=$(builtin umask -p)
+builtin umask 077
+if exec 3>"$file" && exec <"$file" && rm "$file"; then
+  builtin $umask
+  echo >&3 "cd"
+  echo >&3 "PROFILE_HOME='${PROFILE_HOME:-$HOME}'"
+  if [ -n "$PRINCIPAL" ]; then
+    echo >&3 "PRINCIPAL='$PRINCIPAL'"
+    if [ $kerberos = 1 ]; then
+      ccname=$(klist 2>/dev/null | sed -n 's/^Ticket cache: [DF]I[LR][E:]://p')
+      if [ -f "$ccname" ]; then
+        echo >&3 "export KRB5CCNAME='$KRB5CCNAME'"
+        openssl=$(find_working openssl)
+        if [ -n "$openssl" ]; then
+          echo >&3 "KRB5OPENSSL='$openssl'"
+          echo >&3 "KRB5BASE64='$($openssl enc -a -in $ccname)'"
+        fi
+      fi
+    fi
+  fi
+  if [ -n "$DISPLAY" -a -n "$COOKIE" ]; then
+    echo >&3 "xauth add $COOKIE"
+  else
+    echo >&3 "unset DISPLAY"
+  fi
+  if [ ! "$PROFILE_HOME" = "$HOME" ]; then
+    echo >&3 "export SCREENRC=$PROFILE_HOME/.screenrc"
+  fi
+else
+  exit 111
+fi
+
+echo >&3 ". ${PROFILE_HOME:-$HOME}/.bash_profile"
+for profile in "$allusersprofile" "$userprofile"; do
+  [ -f "$profile" ] && cat >&3 2>/dev/null "$profile"
+done
+for environment in "$allusersenvironment" "$userenvironment"; do
+  [ -f "$environment" ] || continue
+  while read -d $'\n' variable; do
+    variable=${variable%%=*}
+    eval "[ -z \${$variable:+set} ] || echo >&3 \"$variable='\$$variable'\""
+  done < "$environment"
+done
+[ $chdir = 1 ] && echo >&3 2>/dev/null "cd - &>/dev/null"
 
-exec sudo -H -u "$user" env BECOME_HOME="$HOME" /bin/bash --rcfile "$profile"
+exec 3>&-
+dir=$(dirname "$0")
+[ "$dir" = "." ] && dir="$PWD"
+exec sudo -H -u "$user" "$dir/became"
+exit 111