rig/commands/lib/admin-path.sh

#!/usr/bin/env bash
# admin-path.sh — assert the admin binaries are REACHABLE, not merely that we
# are root.
#
# Being uid 0 and being able to find useradd are different facts, and rig
# asserted only the first. `su` without `-`, sudo with a sanitised secure_path,
# and several container images all hand you a root shell whose PATH carries no
# /usr/sbin — which is where useradd, usermod and groupadd live on Debian. The
# result was a bare `useradd: command not found` naming a line number inside a
# versioned install root, emitted AFTER a registration token had been read off
# the operator's terminal (#139).
#
# Which binaries this covers is measured, not assumed (Debian 13, 2026-08-01):
#
#   useradd usermod groupadd userdel groupdel   /usr/sbin   package: passwd
#   visudo                                      /usr/sbin   package: sudo
#   gpasswd                                     /usr/bin    package: passwd
#
# Two consequences worth keeping written down. `gpasswd` is in the same PACKAGE
# as useradd but a different DIRECTORY, so it is reachable on a PATH-shorn root
# and does not belong in any of these preflights — do not add it for symmetry.
# And `visudo` shares the directory but not the package, so its absence has a
# second, innocent cause (sudo simply not installed) that the others do not, so
# `rig users apply` checks it separately, after the point where that cause is
# ruled out. See the comment there.
#
# (Spelled without the `.sh` on purpose: test/cli.sh pins that exactly one file
# under commands/ names that script, to catch a second caller appearing. A
# comment is not a caller, but the pin is deliberately blunt and cheap.)
#
# It REFUSES rather than repairing PATH itself. A command that quietly prepends
# /usr/sbin teaches the operator nothing and leaves a misconfigured host
# misconfigured; the same reason bootstrap refuses rather than guessing. The
# message carries the fix so the refusal costs one paste, not an investigation.

# require_admin_bins <bin>... — die unless every one resolves on PATH.
require_admin_bins() {
  local missing=() b
  for b in "$@"; do
    command -v "$b" >/dev/null 2>&1 || missing+=("$b")
  done
  [ "${#missing[@]}" -eq 0 ] && return 0
  # Names the REMEDY, not this script: the operator typed a `rig ...` command,
  # and echoing the internal path back at them is the unhelpful half of the
  # original `useradd: command not found`.
  die "cannot find ${missing[*]} on PATH — it lives in /usr/sbin, which this root shell does not carry (a 'su' without '-' does this, and so do some container images). Re-run the same rig command with: PATH=/usr/sbin:/sbin:\$PATH"
}