| 1 | #!/bin/bash |
| 2 | # Matt's improved version of Fedora's lesspipe.sh |
| 3 | # |
| 4 | # To use this filter with less, define LESSOPEN: |
| 5 | # export LESSOPEN="|lesspipe.sh %s" |
| 6 | |
| 7 | # Updated for "less" that checks our exit code ~ Matt 2010-12-28 |
| 8 | |
| 9 | # This script is entirely driven by the file content, with type detected by |
| 10 | # file(1). For reproducibility and to avoid problems with strange names and |
| 11 | # even symlinks, we do not use the original name of the file for anything. |
| 12 | |
| 13 | set -e |
| 14 | set -o pipefail |
| 15 | #set -x |
| 16 | |
| 17 | # Attach the file to an FD. We will reopen /dev/fd/$f to get as many fresh FDs as |
| 18 | # we need. |
| 19 | exec {f}<"$1" |
| 20 | shift |
| 21 | |
| 22 | function run_stream_stdin { |
| 23 | if [ "$decompressor" == cat ]; then |
| 24 | <&$f "$@" |
| 25 | else |
| 26 | <&$f "$decompressor" | "$@" |
| 27 | fi |
| 28 | } |
| 29 | |
| 30 | function stage_to_file_stdin { |
| 31 | if [ "$decompressor" != cat ]; then |
| 32 | # There is an unavoidable race here, so I am not trying to avoid |
| 33 | # it. If we rewrite the script in Perl, we can use open(undef). |
| 34 | # Integration with in2tempfile looks too hard. |
| 35 | tmpfile="$(mktemp --tmpdir lesspipe.XXXXXXXXXX)" |
| 36 | exec {tf}>"$tmpfile" |
| 37 | rm -f "$tmpfile" |
| 38 | <&$f "$decompressor" >&$tf # Synchronous |
| 39 | # Get a new FD for reading on the tempfile. This might not be |
| 40 | # necessary if the command is just going to reopen it. |
| 41 | exec {f}>&- </dev/fd/$tf {tf}>&- |
| 42 | else |
| 43 | exec <&$f- |
| 44 | fi |
| 45 | } |
| 46 | |
| 47 | # Note: the bash file tests (except -h) follow symlinks. |
| 48 | if [ -f /dev/fd/$f ]; then |
| 49 | # Specify the input as -. This avoids irrelevant "set[ug]id" output for |
| 50 | # executables and also follows the symlink without us having to pass -L. |
| 51 | # We have to reopen stdin to not consume it. |
| 52 | content_type="$(</dev/fd/$f file -b -)" |
| 53 | |
| 54 | case "$content_type" in |
| 55 | ('gzip compressed data'*) |
| 56 | decompressor=gunzip;; |
| 57 | ('bzip2 compressed data'*) |
| 58 | decompressor=bunzip2;; |
| 59 | ('XZ compressed data'*) |
| 60 | decompressor=unxz;; |
| 61 | (*) |
| 62 | decompressor=cat;; |
| 63 | esac |
| 64 | |
| 65 | if [ "$decompressor" != cat ]; then |
| 66 | # Get the real content type. Whatever work the decompressor |
| 67 | # does before it is killed with SIGPIPE, we will duplicate later |
| 68 | # when we read the file, but there is no good alternative: |
| 69 | # - If we do a "tee" with one pipe held for later use, "tee" |
| 70 | # will block once it fills up that pipe. So if "file" needs |
| 71 | # more data than the pipe buffer to make its decision |
| 72 | # (probably unlikely), we could hang. |
| 73 | # - Going ahead and dumping the decompressed data to a temporary |
| 74 | # file is a waste of work if the content type turns out to be |
| 75 | # one for which we have a streaming viewer, but of course we |
| 76 | # don't know that yet. |
| 77 | content_type="$(</dev/fd/$f "$decompressor" | file -b -)" || [ $? == 141 ] # SIGPIPE |
| 78 | fi |
| 79 | |
| 80 | case "$content_type" in |
| 81 | ('troff or preprocessor input'*) |
| 82 | ## Presuming our parent is "less", set COLUMNS based on the width |
| 83 | ## of the terminal. |
| 84 | #exec {pt}>/proc/$PPID/fd/1 |
| 85 | #if [ -t $pt ]; then |
| 86 | # # XXX Does this really use stderr rather than the controlling terminal? |
| 87 | # export COLUMNS="$(bash -i -c 'echo $COLUMNS' 2>&$pt)" |
| 88 | #fi |
| 89 | #exec {pt}>&- |
| 90 | # viapty is a more comprehensive solution than the above. ~ 2011-09-05 |
| 91 | # Hm, by the time we hack in PAGER=cat, maybe it's not any better... ~ 2011-09-06 |
| 92 | run_stream_stdin viapty man -l -;; |
| 93 | (*'tar archive'*) |
| 94 | run_stream_stdin tar -tvv;; |
| 95 | (*'cpio archive'*) |
| 96 | run_stream_stdin cpio --quiet -itv;; |
| 97 | (RPM*) |
| 98 | run_stream_stdin rpm -qivl --changelog -p -;; |
| 99 | (*image*) # FIXME: will catch disk "images" as well as graphical images |
| 100 | if type identify &>/dev/null; then |
| 101 | identify_cmd=(identify) |
| 102 | elif type gm &>/dev/null; then |
| 103 | identify_cmd=(gm identify) |
| 104 | else |
| 105 | ### Give them the binary data. |
| 106 | #echo "No identify available" |
| 107 | #echo "Install ImageMagick or GraphicsMagick to browse images" |
| 108 | identify_cmd=(false) |
| 109 | fi |
| 110 | if [ "${identify_cmd[0]}" != false ]; then |
| 111 | # Make a file so identify won't stage it again with a |
| 112 | # nonreproducible name. (Note that "identify -" will |
| 113 | # stage again even if /dev/stdin is a file!) |
| 114 | stage_to_file_stdin |
| 115 | "${identify_cmd[@]}" /dev/stdin |
| 116 | fi;; |
| 117 | ('OpenDocument Text'|_,'OpenDocument Text Template') |
| 118 | stage_to_file_stdin |
| 119 | ### CUSTOM SCRIPT -- This part cannot be upstreamed unless odt2text is. |
| 120 | odt2text /dev/stdin # based on unzip, needs a file |
| 121 | ;; |
| 122 | # This has to come after the special case for odt2text. |
| 123 | ('Zip archive data'*|_,'OpenDocument'*|_,'OpenOffice 1.x'*) |
| 124 | stage_to_file_stdin |
| 125 | zipinfo /dev/stdin # needs a file |
| 126 | ;; |
| 127 | ('PDF document'*) |
| 128 | run_stream_stdin pdftotext - -;; |
| 129 | ('PostScript document'*) |
| 130 | # If you wanted to see the PostScript source code, sorry... |
| 131 | run_stream_stdin ps2ascii;; |
| 132 | (ELF*'dynamically linked'*) |
| 133 | stage_to_file_stdin # read twice |
| 134 | objdump -xRTdgl /dev/stdin |
| 135 | # The above does not seem to show data sections. Run a separate command |
| 136 | # to show them. (Of course I would prefer a single command.) |
| 137 | objdump -s -j .rodata -j .data /dev/stdin |
| 138 | ;; |
| 139 | (ELF*) |
| 140 | stage_to_file_stdin # read twice |
| 141 | objdump -xdgl /dev/stdin |
| 142 | objdump -s -j .rodata -j .data /dev/stdin |
| 143 | ;; |
| 144 | ('SQLite 3.x database'*) |
| 145 | # TODO: Reimplement copy to a temporary directory to |
| 146 | # handle databases that use write-ahead mode, etc. I had |
| 147 | # implemented this in main VM and I forgot to copy it to |
| 148 | # main-template before shutting down. :( ~ Noted 2015-12-28 |
| 149 | stage_to_file_stdin |
| 150 | # I believe that this will honor a write lock held on an |
| 151 | # uncompressed database by another instance of SQLite. I |
| 152 | # further believe that is what we want. |
| 153 | sqlite3 /dev/stdin .dump # needs a file |
| 154 | ;; |
| 155 | ('compiled Java class data'*) |
| 156 | # Agghhh... why couldn't javap just take a filename? It's clear |
| 157 | # that all it is doing is translating our argument to a file and |
| 158 | # opening that, without checking the correctness of the package |
| 159 | # or class name. |
| 160 | # XXX: Proper cleanup on failure |
| 161 | dir="$(mktemp -d --tmpdir lesspipe-javap.XXXXXXXXXX)" |
| 162 | ln -s /dev/stdin "$dir/Stdin.class" |
| 163 | run_stream_stdin javap -classpath "$dir" -private -s -c -verbose Stdin |
| 164 | rm -rf "$dir" |
| 165 | ;; |
| 166 | # Disabled for now. |
| 167 | #(*.grl) |
| 168 | # stage_to_file_stdin |
| 169 | # head -n 1 /dev/stdin | fold -w 28 |
| 170 | # tail -n +2;; |
| 171 | (*) # Unknown content type. |
| 172 | if [ "$decompressor" != cat ]; then |
| 173 | # Just decompress the file. |
| 174 | <&$f "$decompressor" |
| 175 | else |
| 176 | # We cannot add value in this case. |
| 177 | # Let "less" show the original file. |
| 178 | exit 77 |
| 179 | fi;; |
| 180 | esac |
| 181 | |
| 182 | elif [ -d /dev/fd/$f ]; then |
| 183 | # nip blank line at the end |
| 184 | # XXX: how to make sure "less" has -R enabled? |
| 185 | #ls -H -al --color=always -- /dev/fd/$f/ | head --bytes=-3 |
| 186 | ### Between coreutils-7.6-9.matt1.fc12 and coreutils-8.5-7.fc14, the |
| 187 | ### output has changed to put the \n at the end, so the special hack is |
| 188 | ### no longer necessary (less ignores a final \n) and in fact corrupts |
| 189 | ### the colors. ~ Matt 2011-06-19 |
| 190 | ls -H -al --color=always -- /dev/fd/$f/ |
| 191 | else |
| 192 | # Device/special file. Don't print anything; let less complain about it. |
| 193 | # (For now, we are not interested in content sniffing on pipes. If less |
| 194 | # gained support for calling LESSOPEN for stdin, we might reconsider.) |
| 195 | exit 77 |
| 196 | fi |