#!/bin/sh
# Copyright (c) 2017 Jonas 'Sortie' Termansen.
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#
# tix-check
# Check the operating system installation.

set -e

collection=""
sysroot=""
existence=false
owner=false
permissions=false
unknown_files=false

dashdash=
previous_option=
for argument do
  if test -n "$previous_option"; then
    eval $previous_option=\$argument
    previous_option=
    shift
    continue
  fi

  case $argument in
  *=?*) parameter=$(expr "X$argument" : '[^=]*=\(.*\)' || true) ;;
  *=)   parameter= ;;
  *)    parameter=yes ;;
  esac

  case $dashdash$argument in
  --) dashdash=yes ;;
  --collection=*) collection=$parameter ;;
  --collection) previous_option=collection ;;
  --existence) existence=true ;;
  --owner) owner=true ;;
  --permissions) permissions=true ;;
  --sysroot) previous_option=sysroot ;;
  --sysroot=*) sysroot=$parameter ;;
  --unknown-files) unknown_files=true ;;
  -*) echo "$0: unrecognized option $argument" >&2
      exit 1 ;;
  *) break ;;
  esac

  shift
done

if test -n "$previous_option"; then
  echo "$0: option '$argument' requires an argument" >&2
  exit 1
fi

# TODO: Reject additional operands.

if [ -z "$collection" ]; then
  collection="$sysroot"
fi

if [ -n "$collection" ]; then
  collection=$(cd "$collection" && pwd)
fi

tmp=
trap '[ -n "$tmp" ] && rm -rf "$tmp"' EXIT HUP INT QUIT TERM
tmp=$(mktemp -dt tix-check.XXXXXX)
mkdir -p "$tmp/tmp"
export TMPDIR="$tmp/tmp"

escape_extended_regex_sed() {
  printf "%s\n" "$1" | sed -E -e 's/[[$()*?\+.^{|}'"$2"']/\\\0/g'
}

# TODO: More portable way of doing this.
getuid() {
  stat -- "$1" | grep -E '^UID: ' | sed -E -e 's/^UID: //' -e 's,/.*,,'
}

# TODO: More portable way of doing this.
getgid() {
  stat -- "$1" | grep -E '^GID: ' | sed -E -e 's/^GID: //' -e 's,/.*,,'
}

# TODO: More portable way of doing this.
getmode() {
  stat -- "$1" | grep -E '^Mode: ' | sed -E -e 's,^Mode: [^/]*/,,'
}

# TODO: Rewrite in C with the following model.
# - Every file must be in one state of being tracked:
#   - Be tracked by exactly one manifest.
#   - (Other states?)
#   - Be a local file inside system directories (unknown file).
#   - Be a local file outside system directories.

exit_code=0

# TODO: Store sha256sum of each file in metadata so we can do file
#       consistency checks.
if $existence || $owner || $permissions; then
  for manifest in "$collection/tix/manifest/"*; do
    manifest_name=$(basename -- "$manifest")
    # TODO: Verify absolute paths.
    cat -- "$manifest" | \
    while read -r path; do
      # TODO: Handle symbolic links that are intentionally dangling like
      #       /share/vim/vimrc.
      if [ ! -e "$collection$path" ]; then
        if $existence; then
          printf "%s: %s: %s%s: Missing file\n" "$0" "$manifest_name" "$collection" "$path" >&2
          exit_code=1
        fi
        continue
      fi
      if $owner; then
        expected_uid=0
        expected_gid=0
        uid=$(getuid "$collection$path")
        gid=$(getgid "$collection$path")
        if [ "$uid" != "$expected_uid" ]; then
          printf "%s: %s: %s%s: Owned by uid %s instead of expected uid %s\n" "$0" "$manifest_name" "$collection" "$path" "$uid" "$expected_uid" >&2
          exit_code=1
        fi
        if [ "$gid" != "$expected_gid" ]; then
          printf "%s: %s: %s%s: Owned by gid %s instead of expected gid %s\n" "$0" "$manifest_name" "$collection" "$path" "$gid" "$expected_gid" >&2
          exit_code=1
        fi
      fi
      if $permissions; then
        if [ -L "$collection$path" ]; then
          expected_mode=lrwxrwxrwx
        elif [ -d "$collection$path" ]; then
          expected_mode=drwxr-xr-x
        else
          # TODO: Store the intended file permissions in tix metadata.
          case "$path" in
          /bin/*) expected_mode=-rwxr-xr-x ;;
          /boot/sortix.bin) expected_mode=-rwxr-xr-x ;;
          /etc/grub.d/README) expected_mode=-rw-r--r-- ;;
          /etc/grub.d/*) expected_mode=-rwxr-xr-x ;;
          /libexec/*) expected_mode=-rwxr-xr-x ;;
          /lib/grub/i386-pc/*.exec) expected_mode=-rwxr-xr-x ;;
          /lib/grub/i386-pc/*.image) expected_mode=-rwxr-xr-x ;;
          /lib/grub/i386-pc/*.module) expected_mode=-rwxr-xr-x ;;
          /sbin/*) expected_mode=-rwxr-xr-x ;;
          /src/*) expected_mode= ;; # TODO.
          *) expected_mode=-rw-r--r-- ;;
          esac
        fi
        mode=$(getmode "$collection$path")
        if [ -n "$expected_mode" ] && [ "$mode" != "$expected_mode" ]; then
          printf "%s: %s: %s%s: Mode is %s instead of expected mode %s\n" "$0" "$manifest_name" "$collection" "$path" "$mode" "$expected_mode" >&2
          exit_code=1
        fi
      fi
    done
  done
fi

if $unknown_files; then
  # TODO: More exclusion patterns.
  exclude_directories="/dev|/home|/mnt|/sysmerge|/tix|/tmp|/var/cache|/var/log|/var/run|/var/www"
  # Find all known directories.
  for manifest in "$collection/tix/manifest/"*; do
    # TODO: Verify absolute paths.
    cat -- "$manifest" | \
    grep -Ev '^('"$exclude_directories"')($|/)' |
    while read -r path; do
      if [ -L "$collection$path" ]; then
        :
      elif [ -d "$collection$path" ]; then
        printf "%s\n" "$path"
      fi
    done
  # TODO: pipefail
  done | \
  LC_ALL=C sort -u > "$tmp/directories"

  # Find all known files.
  for manifest in "$collection/tix/manifest/"*; do
    # TODO: Verify absolute paths.
    grep -Ev '^('"$exclude_directories"')/' -- "$manifest"
  # TODO: pipefail
  done | \
  LC_ALL=C sort -u > "$tmp/expected"

  # List the contents of each system directory.
  cat -- "$tmp/directories" | while read -r directory; do
    (cd "${collection:-/}" &&
     printf '%s\n' "$directory" &&
     ls -1A -- ".$directory" |
     sed -E -e "s,^,$(escape_extended_regex_sed "$directory" ,)/," -e 's,//,/,')
  # TODO: pipefail
  done | \
  LC_ALL=C sort -u \
  > "$tmp/actual"

  # TODO: This requires diffutils in the minimal ports.
  diff -- "$tmp/expected" "$tmp/actual" || true

  cp -- "$tmp/directories" /tmp/directories
  cp -- "$tmp/expected" /tmp/expected
  cp -- "$tmp/actual" /tmp/actual
fi

exit $exit_code