This chapter shows how to build the last missing bits of the temporary system: the tools needed by the build machinery of various packages. Now that all circular dependencies have been resolved, we can use a “chroot” environment, completely isolated the host operating system used for the build, except for the running kernel.
For proper operation of the isolated environment, some communication with the running kernel must be established. This is done through the so-called Virtual Kernel File Systems, which must be mounted when entering the chroot environment. You may want to check that they are mounted by issuing findmnt.
Until Section 7.4,
“Entering the Chroot Environment”, the commands must
be run as root, with the LFS variable set. After entering chroot, all commands
are run as root, fortunately without access to the OS of the computer
you built LFS on. Be careful anyway, as it is easy to destroy the
whole LFS system with badly formed commands.