Helper script to create a chroot environment

create-chroot.sh

#!/bin/bash

# ------------------------------------------------------------------------------------------------
# Creates a minimum operating system environment required for selected binaries to run
# Usage: chroot-create.sh "/path/where/to/store/environment" list-of-binaries psql pg_restore
#
# After the environment is created just do as the regular user: fakechroot fakeroot chroot /path/where/to/store/environment /bin/sh
# or directly:                                                  fakechroot fakeroot chroot /path/where/to/store/environment psql --help
# ------------------------------------------------------------------------------------------------

set -e

CHROOT_DIR=$1
BINARIES=$@
BINARIES=${BINARIES[@]:${#CHROOT_DIR}:200}

echo " >> Chroot directory: ${CHROOT_DIR}"
echo " >> Binaries to copy: ${BINARIES}"

copyBinary() {
    for b in $*; do
        echo "   >> Copying binary ${b}"
        cp --parents $b $CHROOT_DIR
    done

    for i in $(ldd $*|grep -v dynamic|cut -d " " -f 3|sed 's/://'|sort|uniq); do
        echo "   >> Copying ${i}"
        cp --parents $i $CHROOT_DIR
    done
}

setupPasswd() {
    echo "   >> Setting up /etc/group and /etc/passwd"
    cp --parents /etc/passwd $CHROOT_DIR
    cp --parents /etc/group $CHROOT_DIR
    if [[ $(cat $CHROOT_DIR/etc/passwd) != *"$(id -u):$(id -g)"* ]]; then
        echo "$(whoami):x:$(id -u):$(id -g)::/home:/bin/sh" >> $CHROOT_DIR/etc/passwd
    fi
    if [[ $(cat $CHROOT_DIR/etc/group) != *"$(whoami):"* ]]; then
        echo "$(whoami):x:$(id -g):" >> $CHROOT_DIR/etc/group
    fi
    echo "$(whoami):!!:11111:0:99999:7:::" >> $CHROOT_DIR/etc/shadow
}


mkdir -p $CHROOT_DIR
mkdir -p $CHROOT_DIR/{dev,etc,home,tmp,proc,root,var}
cp --parents /etc/nsswitch.conf $CHROOT_DIR
echo "nameserver 1.1.1.1" > $CHROOT_DIR/etc/resolv.conf
cp --parents /etc/hosts $CHROOT_DIR
cp --parents /lib/libnss_* $CHROOT_DIR || true
cp -r --parents /usr/share/terminfo $CHROOT_DIR || true
cp --parents /lib64/ld-linux-* $CHROOT_DIR
setupPasswd

ls -la /usr/lib/postgresql/

for binName in ${BINARIES[@]}; do
    echo " >> Checking '${binName}'"
    binPath="${binName}"
    if [[ ! -f "${binPath}" ]]; then
        echo "   .. checking with which"
        binPath=$(which ${binName} || true)

        if [[ ! -f "${binPath}" ]]; then
            echo "   .. checking with find"
            binPath=$((find / -name "${binName}" 2>/dev/null | tail -n -1) || true)
        fi
    fi

    if [[ ! -f "${binPath}" ]]; then
        echo "   >> Cannot find ${binName}"
        exit 1
    fi

    echo " >> copyBinary ${binPath}"
    copyBinary $binPath
done