1#!/usr/bin/env bash
2
3# Purpose: plain text tar format
4# Limitations: - only suitable for text files, directories, and symlinks
5# - stores only filename, content, and mode
6# - not designed for untrusted input
7#
8# Note: must work with bash version 3.2 (macOS)
9
10# Copyright 2017 Roger Luethi
11#
12# Licensed under the Apache License, Version 2.0 (the "License");
13# you may not use this file except in compliance with the License.
14# You may obtain a copy of the License at
15#
16# http://www.apache.org/licenses/LICENSE-2.0
17#
18# Unless required by applicable law or agreed to in writing, software
19# distributed under the License is distributed on an "AS IS" BASIS,
20# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
21# See the License for the specific language governing permissions and
22# limitations under the License.
23
24set -o errexit -o nounset
25
26# Sanitize environment (for instance, standard sorting of glob matches)
27export LC_ALL=C
28
29path=""
30CMD=""
31ARG_STRING="$*"
32
33#------------------------------------------------------------------------------
34# Not all sed implementations can work on null bytes. In order to make ttar
35# work out of the box on macOS, use Python as a stream editor.
36
37USE_PYTHON=0
38
39PYTHON_CREATE_FILTER=$(cat << 'PCF'
40#!/usr/bin/env python
41
42import re
43import sys
44
45for line in sys.stdin:
46 line = re.sub(r'EOF', r'\EOF', line)
47 line = re.sub(r'NULLBYTE', r'\NULLBYTE', line)
48 line = re.sub('\x00', r'NULLBYTE', line)
49 sys.stdout.write(line)
50PCF
51)
52
53PYTHON_EXTRACT_FILTER=$(cat << 'PEF'
54#!/usr/bin/env python
55
56import re
57import sys
58
59for line in sys.stdin:
60 line = re.sub(r'(?<!\\)NULLBYTE', '\x00', line)
61 line = re.sub(r'\\NULLBYTE', 'NULLBYTE', line)
62 line = re.sub(r'([^\\])EOF', r'\1', line)
63 line = re.sub(r'\\EOF', 'EOF', line)
64 sys.stdout.write(line)
65PEF
66)
67
68function test_environment {
69 if [[ "$(echo "a" | sed 's/a/\x0/' | wc -c)" -ne 2 ]]; then
70 echo "WARNING sed unable to handle null bytes, using Python (slow)."
71 if ! which python >/dev/null; then
72 echo "ERROR Python not found. Aborting."
73 exit 2
74 fi
75 USE_PYTHON=1
76 fi
77}
78
79#------------------------------------------------------------------------------
80
81function usage {
82 bname=$(basename "$0")
83 cat << USAGE
84Usage: $bname [-C <DIR>] -c -f <ARCHIVE> <FILE...> (create archive)
85 $bname -t -f <ARCHIVE> (list archive contents)
86 $bname [-C <DIR>] -x -f <ARCHIVE> (extract archive)
87
88Options:
89 -C <DIR> (change directory)
90 -v (verbose)
91 --recursive-unlink (recursively delete existing directory if path
92 collides with file or directory to extract)
93
94Example: Change to sysfs directory, create ttar file from fixtures directory
95 $bname -C sysfs -c -f sysfs/fixtures.ttar fixtures/
96USAGE
97exit "$1"
98}
99
100function vecho {
101 if [ "${VERBOSE:-}" == "yes" ]; then
102 echo >&7 "$@"
103 fi
104}
105
106function set_cmd {
107 if [ -n "$CMD" ]; then
108 echo "ERROR: more than one command given"
109 echo
110 usage 2
111 fi
112 CMD=$1
113}
114
115unset VERBOSE
116unset RECURSIVE_UNLINK
117
118while getopts :cf:-:htxvC: opt; do
119 case $opt in
120 c)
121 set_cmd "create"
122 ;;
123 f)
124 ARCHIVE=$OPTARG
125 ;;
126 h)
127 usage 0
128 ;;
129 t)
130 set_cmd "list"
131 ;;
132 x)
133 set_cmd "extract"
134 ;;
135 v)
136 VERBOSE=yes
137 exec 7>&1
138 ;;
139 C)
140 CDIR=$OPTARG
141 ;;
142 -)
143 case $OPTARG in
144 recursive-unlink)
145 RECURSIVE_UNLINK="yes"
146 ;;
147 *)
148 echo -e "Error: invalid option -$OPTARG"
149 echo
150 usage 1
151 ;;
152 esac
153 ;;
154 *)
155 echo >&2 "ERROR: invalid option -$OPTARG"
156 echo
157 usage 1
158 ;;
159 esac
160done
161
162# Remove processed options from arguments
163shift $(( OPTIND - 1 ));
164
165if [ "${CMD:-}" == "" ]; then
166 echo >&2 "ERROR: no command given"
167 echo
168 usage 1
169elif [ "${ARCHIVE:-}" == "" ]; then
170 echo >&2 "ERROR: no archive name given"
171 echo
172 usage 1
173fi
174
175function list {
176 local path=""
177 local size=0
178 local line_no=0
179 local ttar_file=$1
180 if [ -n "${2:-}" ]; then
181 echo >&2 "ERROR: too many arguments."
182 echo
183 usage 1
184 fi
185 if [ ! -e "$ttar_file" ]; then
186 echo >&2 "ERROR: file not found ($ttar_file)"
187 echo
188 usage 1
189 fi
190 while read -r line; do
191 line_no=$(( line_no + 1 ))
192 if [ $size -gt 0 ]; then
193 size=$(( size - 1 ))
194 continue
195 fi
196 if [[ $line =~ ^Path:\ (.*)$ ]]; then
197 path=${BASH_REMATCH[1]}
198 elif [[ $line =~ ^Lines:\ (.*)$ ]]; then
199 size=${BASH_REMATCH[1]}
200 echo "$path"
201 elif [[ $line =~ ^Directory:\ (.*)$ ]]; then
202 path=${BASH_REMATCH[1]}
203 echo "$path/"
204 elif [[ $line =~ ^SymlinkTo:\ (.*)$ ]]; then
205 echo "$path -> ${BASH_REMATCH[1]}"
206 fi
207 done < "$ttar_file"
208}
209
210function extract {
211 local path=""
212 local size=0
213 local line_no=0
214 local ttar_file=$1
215 if [ -n "${2:-}" ]; then
216 echo >&2 "ERROR: too many arguments."
217 echo
218 usage 1
219 fi
220 if [ ! -e "$ttar_file" ]; then
221 echo >&2 "ERROR: file not found ($ttar_file)"
222 echo
223 usage 1
224 fi
225 while IFS= read -r line; do
226 line_no=$(( line_no + 1 ))
227 local eof_without_newline
228 if [ "$size" -gt 0 ]; then
229 if [[ "$line" =~ [^\\]EOF ]]; then
230 # An EOF not preceded by a backslash indicates that the line
231 # does not end with a newline
232 eof_without_newline=1
233 else
234 eof_without_newline=0
235 fi
236 # Replace NULLBYTE with null byte if at beginning of line
237 # Replace NULLBYTE with null byte unless preceded by backslash
238 # Remove one backslash in front of NULLBYTE (if any)
239 # Remove EOF unless preceded by backslash
240 # Remove one backslash in front of EOF
241 if [ $USE_PYTHON -eq 1 ]; then
242 echo -n "$line" | python -c "$PYTHON_EXTRACT_FILTER" >> "$path"
243 else
244 # The repeated pattern makes up for sed's lack of negative
245 # lookbehind assertions (for consecutive null bytes).
246 echo -n "$line" | \
247 sed -e 's/^NULLBYTE/\x0/g;
248 s/\([^\\]\)NULLBYTE/\1\x0/g;
249 s/\([^\\]\)NULLBYTE/\1\x0/g;
250 s/\\NULLBYTE/NULLBYTE/g;
251 s/\([^\\]\)EOF/\1/g;
252 s/\\EOF/EOF/g;
253 ' >> "$path"
254 fi
255 if [[ "$eof_without_newline" -eq 0 ]]; then
256 echo >> "$path"
257 fi
258 size=$(( size - 1 ))
259 continue
260 fi
261 if [[ $line =~ ^Path:\ (.*)$ ]]; then
262 path=${BASH_REMATCH[1]}
263 if [ -L "$path" ]; then
264 rm "$path"
265 elif [ -d "$path" ]; then
266 if [ "${RECURSIVE_UNLINK:-}" == "yes" ]; then
267 rm -r "$path"
268 else
269 # Safe because symlinks to directories are dealt with above
270 rmdir "$path"
271 fi
272 elif [ -e "$path" ]; then
273 rm "$path"
274 fi
275 elif [[ $line =~ ^Lines:\ (.*)$ ]]; then
276 size=${BASH_REMATCH[1]}
277 # Create file even if it is zero-length.
278 touch "$path"
279 vecho " $path"
280 elif [[ $line =~ ^Mode:\ (.*)$ ]]; then
281 mode=${BASH_REMATCH[1]}
282 chmod "$mode" "$path"
283 vecho "$mode"
284 elif [[ $line =~ ^Directory:\ (.*)$ ]]; then
285 path=${BASH_REMATCH[1]}
286 mkdir -p "$path"
287 vecho " $path/"
288 elif [[ $line =~ ^SymlinkTo:\ (.*)$ ]]; then
289 ln -s "${BASH_REMATCH[1]}" "$path"
290 vecho " $path -> ${BASH_REMATCH[1]}"
291 elif [[ $line =~ ^# ]]; then
292 # Ignore comments between files
293 continue
294 else
295 echo >&2 "ERROR: Unknown keyword on line $line_no: $line"
296 exit 1
297 fi
298 done < "$ttar_file"
299}
300
301function div {
302 echo "# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -" \
303 "- - - - - -"
304}
305
306function get_mode {
307 local mfile=$1
308 if [ -z "${STAT_OPTION:-}" ]; then
309 if stat -c '%a' "$mfile" >/dev/null 2>&1; then
310 # GNU stat
311 STAT_OPTION='-c'
312 STAT_FORMAT='%a'
313 else
314 # BSD stat
315 STAT_OPTION='-f'
316 # Octal output, user/group/other (omit file type, sticky bit)
317 STAT_FORMAT='%OLp'
318 fi
319 fi
320 stat "${STAT_OPTION}" "${STAT_FORMAT}" "$mfile"
321}
322
323function _create {
324 shopt -s nullglob
325 local mode
326 local eof_without_newline
327 while (( "$#" )); do
328 file=$1
329 if [ -L "$file" ]; then
330 echo "Path: $file"
331 symlinkTo=$(readlink "$file")
332 echo "SymlinkTo: $symlinkTo"
333 vecho " $file -> $symlinkTo"
334 div
335 elif [ -d "$file" ]; then
336 # Strip trailing slash (if there is one)
337 file=${file%/}
338 echo "Directory: $file"
339 mode=$(get_mode "$file")
340 echo "Mode: $mode"
341 vecho "$mode $file/"
342 div
343 # Find all files and dirs, including hidden/dot files
344 for x in "$file/"{*,.[^.]*}; do
345 _create "$x"
346 done
347 elif [ -f "$file" ]; then
348 echo "Path: $file"
349 lines=$(wc -l "$file"|awk '{print $1}')
350 eof_without_newline=0
351 if [[ "$(wc -c "$file"|awk '{print $1}')" -gt 0 ]] && \
352 [[ "$(tail -c 1 "$file" | wc -l)" -eq 0 ]]; then
353 eof_without_newline=1
354 lines=$((lines+1))
355 fi
356 echo "Lines: $lines"
357 # Add backslash in front of EOF
358 # Add backslash in front of NULLBYTE
359 # Replace null byte with NULLBYTE
360 if [ $USE_PYTHON -eq 1 ]; then
361 < "$file" python -c "$PYTHON_CREATE_FILTER"
362 else
363 < "$file" \
364 sed 's/EOF/\\EOF/g;
365 s/NULLBYTE/\\NULLBYTE/g;
366 s/\x0/NULLBYTE/g;
367 '
368 fi
369 if [[ "$eof_without_newline" -eq 1 ]]; then
370 # Finish line with EOF to indicate that the original line did
371 # not end with a linefeed
372 echo "EOF"
373 fi
374 mode=$(get_mode "$file")
375 echo "Mode: $mode"
376 vecho "$mode $file"
377 div
378 else
379 echo >&2 "ERROR: file not found ($file in $(pwd))"
380 exit 2
381 fi
382 shift
383 done
384}
385
386function create {
387 ttar_file=$1
388 shift
389 if [ -z "${1:-}" ]; then
390 echo >&2 "ERROR: missing arguments."
391 echo
392 usage 1
393 fi
394 if [ -e "$ttar_file" ]; then
395 rm "$ttar_file"
396 fi
397 exec > "$ttar_file"
398 echo "# Archive created by ttar $ARG_STRING"
399 _create "$@"
400}
401
402test_environment
403
404if [ -n "${CDIR:-}" ]; then
405 if [[ "$ARCHIVE" != /* ]]; then
406 # Relative path: preserve the archive's location before changing
407 # directory
408 ARCHIVE="$(pwd)/$ARCHIVE"
409 fi
410 cd "$CDIR"
411fi
412
413"$CMD" "$ARCHIVE" "$@"
View as plain text