xz/src/scripts/xzgrep.in

#!@POSIX_SHELL@
# SPDX-License-Identifier: GPL-2.0-or-later

# xzgrep -- a wrapper around a grep program that decompresses files as needed
# Adapted from a version sent by Charles Levert <charles@comm.polymtl.ca>

# Copyright (C) 1998, 2001, 2002, 2006, 2007 Free Software Foundation
# Copyright (C) 1993 Jean-loup Gailly

# Modified for XZ Utils by Andrew Dudman and Lasse Collin.

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

@enable_path_for_scripts@
#SET_PATH - This line is a placeholder to ease patching this script.

# Instead of unsetting XZ_OPT, just make sure that xz will use file format
# autodetection. This way memory usage limit and thread limit can be
# specified via XZ_OPT. With gzip, bzip2, and lzop it's OK to just unset the
# environment variables.
xz='@xz@ --format=auto'
unset GZIP BZIP BZIP2 LZOP

case ${0##*/} in
  *egrep*) prog=xzegrep; grep=${GREP:-grep -E};;
  *fgrep*) prog=xzfgrep; grep=${GREP:-grep -F};;
  *)       prog=xzgrep; grep=${GREP:-grep};;
esac

version="$prog (@PACKAGE_NAME@) @PACKAGE_VERSION@"

usage="Usage: ${0##*/} [OPTION]... [-e] PATTERN [FILE]...
Look for instances of PATTERN in the input FILEs, using their
uncompressed contents if they are compressed.

OPTIONs are the same as for '$grep'.

Report bugs to <@PACKAGE_BUGREPORT@>."

# sed script to escape all ' for the shell, and then (to handle trailing
# newlines correctly) turn trailing X on last line into '.
escape='
  s/'\''/'\''\\'\'''\''/g
  $s/X$/'\''/
'
operands=
have_pat=0
files_with_matches=0
files_without_matches=0
no_filename=0
with_filename=0

# See if -H and --label options are supported (GNU and *BSDs).
if test f:x = "$(eval "echo x | $grep -H --label=f x 2> /dev/null")"; then
  grep_supports_label=1
else
  grep_supports_label=0
fi

while test $# -ne 0; do
  option=$1
  shift
  optarg=

  case $option in
  (-[0123456789abcdEFGhHiIKlLnoPqrRsTuUvVwxyzZ]*[!0123456789]*)
    # Something like -Fiv was specified, that is, $option contains more
    # than one option of which the first option (in this example -F)
    # doesn't take an argument. Split the first option into a standalone
    # argument and continue parsing the rest of the options (in this example,
    # replace -Fiv with -iv in the argument list and set option=-F).
    #
    # If there are digits [0-9] they are treated as if they were a single
    # option character because this syntax is an alias for -C for GNU grep.
    # For example, "grep -25F" is equivalent to "grep -C25 -F". If only
    # digits are specified like "grep -25" we don't get here because the
    # above pattern in the case-statement doesn't match such strings.
    arg2=-\'$(LC_ALL=C expr "X${option}X" : 'X-.[0-9]*\(.*\)' |
                LC_ALL=C sed "$escape")
    eval "set -- $arg2 "'${1+"$@"}'
    option=$(LC_ALL=C expr "X$option" : 'X\(-.[0-9]*\)');;
  (--binary-*=* | --[lm]a*=* | --reg*=*)
    # These options require an argument and an argument has been provided
    # with the --foo=argument syntax. All is good.
    ;;
  (-[ABCDefmX] | --binary-* | --file | --[lm]a* | --reg*)
    # These options require an argument which should now be in $1.
    # If it isn't, display an error and exit.
    case ${1?"$option option requires an argument"} in
    (*\'*)
      optarg=" '"$(printf '%sX\n' "$1" | LC_ALL=C sed "$escape");;
    (*)
      optarg=" '$1'";;
    esac
    shift;;
  (--)
    break;;
  (-?*)
    ;;
  (*)
    case $option in
    (*\'*)
      operands="$operands '"$(printf '%sX\n' "$option" |
                                LC_ALL=C sed "$escape");;
    (*)
      operands="$operands '$option'";;
    esac
    ${POSIXLY_CORRECT+break}
    continue;;
  esac

  case $option in
  (-[drRzZ] | --di* | --exc* | --inc* | --rec* | --nu*)
    printf >&2 '%s: %s: Option not supported\n' "$0" "$option"
    exit 2;;
  (-[ef]* | --file | --file=* | --reg*)
    have_pat=1;;
  (--h | --he | --hel | --help)
    printf '%s\n' "$usage" || exit 2
    exit;;
  (-H | --wi | --wit | --with | --with- | --with-f | --with-fi \
  | --with-fil | --with-file | --with-filen | --with-filena | --with-filenam \
  | --with-filename)
    with_filename=1
    continue;;
  (-l | --files-with-*)
    files_with_matches=1
    continue;;
  (-L | --files-witho*)
    files_without_matches=1
    continue;;
  (-h | --no-f*)
    no_filename=1;;
  (-V | --v | --ve | --ver | --vers | --versi | --versio | --version)
    printf '%s\n' "$version" || exit 2
    exit;;
  esac

  case $option in
  (*\'?*)
    option=\'$(printf '%sX\n' "$option" | LC_ALL=C sed "$escape");;
  (*)
    option="'$option'";;
  esac

  grep="$grep $option$optarg"
done

eval "set -- $operands "'${1+"$@"}'

if test $have_pat -eq 0; then
  case ${1?"Missing pattern; try '${0##*/} --help' for help"} in
  (*\'*)
    grep="$grep -e '"$(printf '%sX\n' "$1" | LC_ALL=C sed "$escape");;
  (*)
    grep="$grep -e '$1'";;
  esac
  shift
fi

if test $# -eq 0; then
  set -- -
fi

exec 3>&1

# res=1 means that no file matched yet
res=1

for i; do
  case $i in
    *[-.][zZ] | *_z | *[-.]gz | *.t[ag]z) uncompress="gzip -cdf";;
    *[-.]bz2 | *[-.]tbz | *.tbz2) uncompress="bzip2 -cdf";;
    *[-.]lzo | *[-.]tzo) uncompress="lzop -cdf";;
    *[-.]zst | *[-.]tzst) uncompress="zstd -cdfq";; # zstd needs -q.
    *[-.]lz4) uncompress="lz4 -cdf";;
    *) uncompress="$xz -cdfqQ";; # -qQ to ignore warnings like unsupp. check.
  esac
  # xz_status will hold the decompressor's exit status.
  # Exit status of grep (and in rare cases, printf or sed) is
  # available as the exit status of this assignment command.
  xz_status=$(
    exec 5>&1
    ($uncompress -- "$i" 5>&-; echo $? >&5) 3>&- |
    if test $files_with_matches -eq 1; then
      eval "$grep -q" && { printf '%s\n' "$i" || exit 2; }
    elif test $files_without_matches -eq 1; then
      eval "$grep -q" || {
        r=$?
        if test $r -eq 1; then
          printf '%s\n' "$i" || r=2
        fi
        exit $r
      }
    elif test $with_filename -eq 0 &&
         { test $# -eq 1 || test $no_filename -eq 1; }; then
      eval "$grep"
    elif test $grep_supports_label -eq 1; then
      # The grep implementation in use allows us to specify the filename
      # that grep will prefix to the output lines. This is faster and
      # less prone to security bugs than the fallback method that uses sed.
      # This also avoids confusing output with GNU grep >= 3.5 (2020-09-27)
      # which prints "binary file matches" to stderr instead of stdout.
      #
      # If reading from stdin, let grep use whatever name it prefers for
      # stdin. With GNU grep it is a locale-specific translated string.
      if test "x$i" = "x-"; then
        eval "$grep -H"
      else
        eval "$grep -H --label \"\$i\""
      fi
    else
      # Append a colon so that the last character will never be a newline
      # which would otherwise get lost in shell command substitution.
      i="$i:"

      # Escape & \ | and newlines only if such characters are present
      # (speed optimization).
      case $i in
      (*'
'* | *'&'* | *'\'* | *'|'*)
        # If sed fails, set i to a known safe string to ensure that
        # failing sed did not create a half-escaped dangerous string.
        i=$(printf '%s\n' "$i" | LC_ALL=C sed 's/[&\|]/\\&/g; $!s/$/\\/') ||
            i='(unknown filename):';;
      esac

      # $i already ends with a colon so do not add it here.
      sed_script="s|^|$i|"

      # If grep or sed fails, pick the larger value of the two exit statuses.
      # If sed fails, use at least 2 since we use >= 2 to indicate errors.
      r=$(
        exec 4>&1
        (eval "$grep" 4>&-; echo $? >&4) 3>&- |
            LC_ALL=C sed "$sed_script" >&3 4>&-
      ) || {
        sed_status=$?
        test "$sed_status" -lt 2 && sed_status=2
        test "$r" -lt "$sed_status" && r=$sed_status
      }
      exit $r
    fi >&3 5>&-
  )
  r=$?

  # If grep or sed or other non-decompression command failed with a signal,
  # exit immediately and ignore the possible remaining files.
  #
  # NOTE: Instead of 128 + signal_number, some shells use
  # 256 + signal_number (ksh) or 384 + signal_number (yash).
  # This is fine for us since their "exit" and "kill -l" commands take
  # this into account. (At least the versions I tried do but there is
  # a report of an old ksh variant whose "exit" truncates the exit status
  # to 8 bits without any special handling for values indicating a signal.)
  test "$r" -ge 128 && exit "$r"

  if test -z "$xz_status"; then
    # Something unusual happened, for example, we got a signal and
    # the exit status of the decompressor was never echoed and thus
    # $xz_status is empty. Exit immediately and ignore the possible
    # remaining files.
    exit 2
  elif test "$xz_status" -ge 128; then
    # The decompressor died due to a signal. SIGPIPE is ignored since it can
    # occur if grep exits before the whole file has been decompressed (grep -q
    # can do that). If the decompressor died with some other signal, exit
    # immediately and ignore the possible remaining files.
    test "$(kill -l "$xz_status" 2> /dev/null)" != "PIPE" && exit "$xz_status"
  elif test "$xz_status" -gt 0; then
    # Decompression failed but we will continue with the remaining
    # files anwyway. Set exit status to at least 2 to indicate an error.
    test "$r" -lt 2 && r=2
  fi

  # Since res=1 is the initial value, we only need to care about
  # matches (r == 0) and errors (r >= 2) here; r == 1 can be ignored.
  if test "$r" -ge 2; then
    # An error occurred in decompressor, grep, or some other command. Update
    # res unless a larger error code has been seen with an earlier file.
    test "$res" -lt "$r" && res=$r
  elif test "$r" -eq 0; then
    # grep found a match and no errors occurred. Update res if no errors have
    # occurred with earlier files.
    test "$res" -eq 1 && res=0
  fi
done

# 0: At least one file matched and no errors occurred.
# 1: No matches were found and no errors occurred.
# >=2: Error. It's unknown if matches were found.
exit "$res"