From 9221d7b8e245d8517afd0f8575f634f2d800a255 Mon Sep 17 00:00:00 2001
From: cyril constantin <constcyr@gmail.com>
Date: Sun, 20 Sep 2026 11:07:12 +0200
Subject: [PATCH] up

---
 mount_chroot.sh | 186 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 186 insertions(+)
 create mode 100755 mount_chroot.sh

diff --git a/mount_chroot.sh b/mount_chroot.sh
new file mode 100755
index 0000000..be3ea81
--- /dev/null
+++ b/mount_chroot.sh
@@ -0,0 +1,186 @@
+#!/usr/bin/env bash
+
+target=$1
+
+ask_for_execution() {
+    USER_ANSWER="?";
+    while [ "${USER_ANSWER}" != "n" ] && [ "${USER_ANSWER}" != "y" ] && [ "${USER_ANSWER}" != "q" ]
+    do
+        echo -n "Is this the good target ? [y/n/q]"
+        read -r -n 1 USER_ANSWER
+        echo "";
+    done
+    if [ "$USER_ANSWER" == "y" ]
+    then
+        return 0
+    elif [ "$USER_ANSWER" == "n" ]
+    then
+        return 1
+    elif [ "$USER_ANSWER" == "q" ]
+    then
+        exit 0
+    else
+        exit 0
+    fi
+}
+
+check_virtual_kernel_filesystems()
+{
+    echo "call check_virtual_kernel_filesystems"
+    if mount |grep -q "udev on ${target}/dev type devtmpfs"        && \
+       mount |grep -q "devpts on ${target}/dev/pts type devpts"    && \
+       mount |grep -q "proc on ${target}/proc type proc"           && \
+       mount |grep -q "sysfs on ${target}/sys type sysfs"          && \
+       mount |grep -q "tmpfs on ${target}/run type tmpfs"          && \
+       mount |grep -q "tmpfs on ${target}/dev/shm type tmpfs"
+    then
+        echo "Ok, Filesystems are ready for chroot"
+        return 0
+    else
+        echo "Warning : Not ready for chroot !!!"
+        return 1
+    fi
+}
+
+mount_virtual_kernel_filesystem()
+{
+  echo "call mount_virtual_kernel_filesystem"
+  echo "sudo operation : mount dev sys proc sys run /dev/shm on ${target}"
+  sudo /usr/bin/mount -v --bind /dev "${target}/dev" || return 1
+  sudo /usr/bin/mount -vt devpts devpts -o gid=5,mode=0620 "${target}/dev/pts" || return 1
+  sudo /usr/bin/mount -vt proc proc "${target}/proc" || return 1
+  sudo /usr/bin/mount -vt sysfs sysfs "${target}/sys" || return 1
+  sudo /usr/bin/mount -vt tmpfs tmpfs "${target}/run" || return 1
+  echo "Content of ${target}/dev :"
+  ls -l "${target}/dev/"
+  echo "Content of ${target}/dev/shm :"
+  ls -l "${target}/dev/shm"
+  if [ -h "${target}/dev/shm" ]
+  then
+      echo /usr/bin/install -v -d -m 1777 "${target}$(realpath /dev/shm)" || return 1
+      sudo /usr/bin/install -v -d -m 1777 "${target}$(realpath /dev/shm)" || return 1
+  else
+      echo /usr/bin/mount -vt tmpfs -o nosuid,nodev tmpfs "${target}/dev/shm" || return 1
+      sudo /usr/bin/mount -vt tmpfs -o nosuid,nodev tmpfs "${target}/dev/shm" || return 1
+  fi
+  return 0
+}
+
+cat > "${HOME}"/target_chroot.sh <<EOSF
+if ! mount |grep -q "proc on ${target}/proc type proc"
+then
+    echo "chroot is not available at this step"
+    exit 1
+fi
+sudo /usr/sbin/chroot ${target} /usr/bin/env -i \
+    HOME=/root                          \
+    TERM="${TERM}"                      \
+    debian_chroot=" ${target} "           \
+    PS1='(chroot ${target}) \u:\w \$ '   \
+    PATH=/usr/bin:/usr/sbin             \
+    /bin/bash --login
+EOSF
+
+cat > "/tmp/$(whoami)_sudo" << EOF
+$(whoami) ALL = NOPASSWD: /usr/bin/mount * ${target}*
+$(whoami) ALL = NOPASSWD: /usr/sbin/chroot ${target}*
+EOF
+
+target_chroot()
+{
+    echo "call target_chroot $1"
+    CHROOTFILE=$1
+    sed "1iif [[ ! \"\${UID\}\" -eq 0 ]] && [ ! -e ${CHROOTFILE} ]" -i "${CHROOTFILE}"
+    sed "2ithen" -i "${CHROOTFILE}"
+    sed "3iecho \"bad chroot\"" -i "${CHROOTFILE}"
+    sed "4iexit 1" -i "${CHROOTFILE}"
+    sed "5ielse" -i "${CHROOTFILE}"
+    sed "\$afi" -i "${CHROOTFILE}"
+    if cat "${CHROOTFILE}" | sudo /usr/sbin/chroot "${target}" /usr/bin/env -i   \
+            HOME=/root                      \
+            TERM="$TERM"                    \
+            debian_chroot=" ${target} "           \
+            PS1='(${target} chroot) \u:\w\$ '     \
+            PATH=/usr/bin:/usr/sbin         \
+            /bin/bash 
+    then
+        echo "command succeed"
+        return 0
+    else
+        return 1
+    fi
+}
+
+usage()
+{
+    echo "Prepare an valid chroot environment"
+    echo "$ mount_chroot.sh target [filename]"
+    echo "Examples:"
+    echo "$ bash mount_chroot.sh /mnt/sid"
+    echo "$ bash mount_chroot.sh /mnt/sid myscript.sh"
+    exit 0
+}
+
+main()
+{
+    nbargs=$#
+
+    if [[ ${nbargs} -ge 1 ]]
+    then
+        target=$1
+    else
+        echo "--- Give at least target as argument"
+        usage
+    fi
+
+    echo "--- chroot target is ${target}"
+
+    if [ ! -d "${target}" ]
+    then
+        echo "--- Error: not a directory"
+        exit 1
+    fi
+
+    if [[ ! "${target}" =~ ^/mnt/ ]]
+    then
+        echo "--- Error: not mounted under /mnt"
+        exit 1
+    fi
+
+    if ! ask_for_execution
+    then
+        echo "--- Give the good target"
+        exit 1
+    fi
+
+    if ! check_virtual_kernel_filesystems
+    then
+        if ! mount_virtual_kernel_filesystem
+        then
+            echo "Mount failure. Please fix it!"
+            exit 1
+        fi
+        if ! check_virtual_kernel_filesystems
+        then
+            echo "Mount failure. Please fix it!"
+            exit 1
+        fi
+    fi
+
+    if [[ ${nbargs} -eq 1 ]]
+    then
+        bash ~/target_chroot.sh
+    elif [[ ${nbargs} -ge 2 ]]
+    then
+        shift
+        script="$*"
+        echo "--- script is ${script}"
+        target_chroot "${script}"
+    fi
+
+}
+
+if [[ "${BASH_SOURCE[0]}" == "$0" ]]
+then
+    main "$@"
+fi