By wrapping $(cat) in an eval, redirections and other advanced
syntax can now work in the early prompts.
Also, since "set -E" is broken is the early bash, fall back to
using "set -e" and an EXIT trap, until we can upgrade to a bash
version that already has working "set -E", or perhaps backport
it to 2.05b.
This is needed to make the monitoring/recovery shell on tty2 work,
as the default console is tty0, which will just print to whichever
virtual console is active at the moment, making the shell unusable.
We spawn a shell:
- When Bash is first built, on tty2. This shell uses the old Bash,
so interactive mode needs to be emulated using redirection. Thus,
entering commands needs to be done using Enter followed by Ctrl+D,
and certain redirection features are unavailable.
- After moving the system to disk, on tty2. Old Bash, same limitations.
- After 2nd Bash is built, on tty3. This is a fully functional shell.
This is disabled in chroot-like bootstrap modes, or when -i is not set.
Before the simplify refactor, the convention was to name the first
or default build script "<package name>.sh". The refactor changed
this default to "pass1.sh", with "pass2.sh" and so on used for
subsequent passes. This wasn't an issue when building usig scripts
generated by script-generator (which explicitly declares the build
script to use), but broke running "build <package name>" without
an explicit script name from the post-bootstrap bash prompt.
By deriving the script name from the current revision/pass number,
this commit restores that functionality.
An unfortunate blemish is that we number build scripts from 1, but
repo tarballs from 0 - it would be nice to standardize on a single
indexing convention.
The Linux kernel won't autocreate /dev/shm inside devtmpfs.
Without it, semaphores won't work properly in Python.
Previously, /dev/shm was set up in populate_device_nodes, but we
no longer run that after booting into Linux.
The sysrq shutdown trigger takes some time to fully shut down the system,
during which init is expected to continue running. Since after.sh is the
last step in our init, if it quits before shutdown is complete, Linux will
panic with "Attempted to kill init".
Add an infinite loop after shutdown is issued via sysrq to prevent this.