#! /usr/bin/perl

use warnings;
use strict;
BEGIN { pop @INC if $INC[-1] eq '.' };

use Pod::Usage;
use Getopt::Long qw(:config no_ignore_case);
use File::Basename;

# Copyright (c) 2007-2017 University of Cambridge.
# Copyright (c) The Exim Maintainers 2020 - 2021
# See the file NOTICE for conditions of use and distribution.

# Except when they appear in comments, the following placeholders in this
# source are replaced when it is turned into a runnable script:
#
# PERL_COMMAND
# ZCAT_COMMAND
# COMPRESS_SUFFIX

# This file has been so processed.

# This is a perl script which extracts from an Exim log all entries
# for all messages that have an entry that matches a given pattern.
# If *any* entry for a particular message matches the pattern, *all*
# entries for that message are displayed.

# We buffer up information on a per-message basis. It is done this way rather
# than reading the input twice so that the input can be a pipe.

# There must be one argument, which is the pattern. Subsequent arguments
# are the files to scan; if none, the standard input is read. If any file
# appears to be compressed, it is passed through zcat. We can't just do this
# for all files, because zcat chokes on non-compressed files.

# Performance optimized in 02/02/2007 by Jori Hamalainen
# Typical run time acceleration: 4 times


use POSIX qw(mktime);


# This subroutine converts a time/date string from an Exim log line into
# the number of seconds since the epoch. It handles optional timezone
# information.

sub seconds
  {
  my($year,$month,$day,$hour,$min,$sec,$tzs,$tzh,$tzm) =
    $_[0] =~ /^(\d{4})-(\d\d)-(\d\d)\s(\d\d):(\d\d):(\d\d)(?:.\d+)?(?>\s([+-])(\d\d)(\d\d))?/o;

  my $seconds = mktime $sec, $min, $hour, $day, $month - 1, $year - 1900;

  if (defined $tzs)
    {
    $seconds -= $tzh * 3600 + $tzm * 60 if $tzs eq "+";
    $seconds += $tzh * 3600 + $tzm * 60 if $tzs eq "-";
    }

  return $seconds;
  }


# This subroutine processes a single line (in $_) from a log file. Program
# defensively against short lines finding their way into the log.

my (%saved, %id_list, $pattern);

my $queue_time  = -1;
my $insensitive = 1;
my $invert      = 0;
my $related     = 0;
my $use_pager   = 1;
my $literal     = 0;


# If using "related" option, have to track extra message IDs
my $related_re='';
my @Mids = ();

sub do_line
  {

  # Convert syslog lines to mainlog format, as in eximstats.

  if (!/^\d{4}-/o) { $_ =~ s/^.*? exim\b.*?: //o; }

  return unless
    my($date,$id) = /^(\d{4}-\d\d-\d\d \d\d:\d\d:\d\d(?:\.\d+)? (?:[+-]\d{4} )?)(?:\[\d+\] )?(\w{6}\-\w{6}\-\w{2})?/o;

  # Handle the case when the log line belongs to a specific message. We save
  # lines for specific messages until the message is complete. Then either print
  # or discard.

  if (defined $id)
    {
    $saved{$id} = '' unless defined($saved{$id});

    # Save up the data for this message in case it becomes interesting later.

    $saved{$id} .= $_;

    # Are we interested in this id ? Short circuit if we already were interested.

    if ($invert)
      {
      $id_list{$id} = 1 if (!defined($id_list{$id}));
      $id_list{$id} = 0 if (($insensitive && /$pattern/io) || /$pattern/o);
      }
    else
      {
      if (defined $id_list{$id} ||
	($insensitive && /$pattern/io) || /$pattern/o)
	{
	$id_list{$id} = 1;
	get_related_ids($id) if $related;
	}
      elsif ($related && $related_re)
	{
	grep_for_related($_, $id);
	}
      }

    # See if this is a completion for some message. If it is interesting,
    # print it, but in any event, throw away what was saved.

    if (index($_, 'Completed') != -1 ||
	index($_, 'SMTP data timeout') != -1 ||
	  (index($_, 'rejected') != -1 &&
	    /^(\d{4}-\d\d-\d\d \d\d:\d\d:\d\d(?:\.\d+)? (?:[+-]\d{4} )?)(?:\[\d+\] )?\w{6}\-\w{6}\-\w{2} rejected/o))
      {
      if ($queue_time != -1 &&
	  $saved{$id} =~ /^(\d{4}-\d\d-\d\d \d\d:\d\d:\d\d ([+-]\d{4} )?)/o)
	{
	my $old_sec = &seconds($1);
	my $sec = &seconds($date);
	$id_list{$id} = 0 if $id_list{$id} && $sec - $old_sec <= $queue_time;
	}

      print "$saved{$id}\n" if ($id_list{$id});
      delete $id_list{$id};
      delete $saved{$id};
      }
    }

  # Handle the case where the log line does not belong to a specific message.
  # Print it if it is interesting.

  elsif ( ($invert && (($insensitive && !/$pattern/io) || !/$pattern/o)) ||
	 (!$invert && (($insensitive &&  /$pattern/io) ||  /$pattern/o)) )
    { print "$_\n"; }
  }

# Rotated log files are frequently compressed and there are a variety of
# formats it could be compressed with. Rather than use just one that is
# detected and hardcoded at Exim compile time, detect and use what the
# logfile is compressed with on the fly.
#
# List of known compression extensions and their associated commands:
my $compressors = {
  gz   => { cmd => 'zcat',  args => '' },
  bz2  => { cmd => 'bzcat', args => '' },
  xz   => { cmd => 'xzcat', args => '' },
  lzma => { cmd => 'lzma',  args => '-dc' },
  zst  => { cmd => 'zstdcat', args => '' },
};
my $csearch = 0;

sub detect_compressor_bin
  {
  my $ext = shift();
  my $c = $compressors->{$ext}->{cmd};
  $compressors->{$ext}->{bin} = `which $c 2>/dev/null`;
  chomp($compressors->{$ext}->{bin});
  }

sub detect_compressor_capable
  {
  my $filename = shift();
  map { &detect_compressor_bin($_) } keys %$compressors
    if (!$csearch);
  $csearch = 1;
  return undef
    unless (grep {$filename =~ /\.(?:$_)$/} keys %$compressors);
  # Loop through them, figure out which one it detected,
  # and build the commandline.
  my $cmdline = undef;
  foreach my $ext (keys %$compressors)
    {
    if ($filename =~ /\.(?:$ext)$/)
      {
      # Just die if compressor not found; if this occurs in the middle of
      # two valid files with a lot of matches, error could easily be missed.
      die("Didn't find $ext decompressor for $filename\n")
        if ($compressors->{$ext}->{bin} eq '');
      $cmdline = $compressors->{$ext}->{bin} ." ".
                   $compressors->{$ext}->{args};
      last;
      }
    }
  return $cmdline;
  }

sub grep_for_related
  {
  my ($line,$id) = @_;
  $id_list{$id} = 1 if $line =~ m/$related_re/;
  }

sub get_related_ids
  {
  my ($id) = @_;
  push @Mids, $id unless grep /\b$id\b/, @Mids;
  my $re = join '|', @Mids;
  $related_re = qr/$re/;
  }

# The main program. Extract the pattern and make sure any relevant characters
# are quoted if the -l flag is given. The -t flag gives a time-on-queue value
# which is an additional condition. The -M flag will also display "related"
# loglines (msgid from matched lines is searched in following lines).

GetOptions(
    'I|sensitive' => sub { $insensitive = 0 },
      'l|literal' => \$literal,
      'M|related' => \$related,
      't|queue-time=i' => \$queue_time,
      'pager!'         => \$use_pager,
      'v|invert'       => \$invert,
      'h|help'         => sub { pod2usage(-exit => 0, -verbose => 1) },
      'm|man'          => sub {
        pod2usage(
            -exit      => 0,
            -verbose   => 2,
            -noperldoc => system('perldoc -V 2>/dev/null >&2')
        );
      },
      'version'        => sub {
            print basename($0) . ": $0\n",
                "build: 4.96\n",
                "perl(runtime): $]\n";
            exit 0;
      },
) and @ARGV or pod2usage;

$pattern = shift @ARGV;
$pattern = quotemeta $pattern if $literal;

# Start a pager if output goes to a terminal
if (-t 1 and $use_pager)
  {
  # for perl >= v5.10.x: foreach ($ENV{PAGER}//(), 'less', 'more')
  foreach (defined $ENV{PAGER} ? $ENV{PAGER} : (), 'less', 'more')
    {
    local $ENV{LESS} .= ' --no-init --quit-if-one-screen';
    open(my $pager, '|-', $_) or next;
    select $pager;
    last;
    }
  }

# If file arguments are given, open each one and process according as it is
# is compressed or not.

if (@ARGV)
  {
  foreach (@ARGV)
    {
    my $filename = $_;
    if (-x 'zcat' && $filename =~ /\.(?:gz)$/o)
      {
      open(LOG, "zcat $filename |") ||
        die "Unable to zcat $filename: $!\n";
      }
    elsif (my $cmdline = &detect_compressor_capable($filename))
      {
      open(LOG, "$cmdline $filename |") ||
        die "Unable to decompress $filename: $!\n";
      }
    else
      {
      open(LOG, "<$filename") || die "Unable to open $filename: $!\n";
      }
    do_line() while (<LOG>);
    close(LOG);
    }
  }

# If no files are named, process STDIN only

else { do_line() while (<STDIN>); }

# At the end of processing all the input, print any uncompleted messages.

for (keys %id_list)
  {
  print "+++ $_ has not completed +++\n$saved{$_}\n";
  }

__END__

=head1 NAME

exigrep - search Exim's main log

=head1 SYNOPSIS

B<exigrep> [options] pattern [log] ...

=head1 DESCRIPTION

The B<exigrep> utility is a Perl script that searches one or more main log
files for entries that match a given pattern.  When it finds  a  match,
it  extracts  all  the  log  entries for the relevant message, not just
those that match the pattern.  Thus, B<exigrep> can extract  complete  log
entries  for  a  given  message, or all mail for a given user, or for a
given host, for example.

If no file names are given on the command line, the standard input is read.

For known file extensions indicating compression (F<.gz>, F<.bz2>, F<.xz>,
F<.lzma>, and F<.zst>) a suitable de-compressor is used, if available.

The output is sent through a pager if a terminal is connected to STDOUT. As
pager are considered: C<$ENV{PAGER}>, C<less>, C<more>.

=head1 OPTIONS

=over

=item B<-l>|B<--literal>

This means 'literal', that is, treat all characters in the
pattern  as standing for themselves.  Otherwise the pattern must be a
Perl regular expression.  The pattern match is case-insensitive.

=item B<-t>|B<--queue-time> I<seconds>

Limit the output to messages that spent at least I<seconds> in the
queue.

=item B<-I>|B<--sensitive>

Do a case sensitive search.

=item B<-v>|B<--invert>

Invert the meaning of the search pattern. That is, print message log
entries that are not related to that pattern.

=item B<-M>|B<--related>

Search for related messages too.

=item B<--no-pager>

Do not use a pager, even if STDOUT is connected to a terminal.

=item B<-h>|B<--help>

Print a short reference help. For more detailed help try L<exigrep(8)>,
or C<exigrep --man>.

=item B<-m>|B<--man>

Print this manual page of B<exigrep>.

=back

=head1 SEE ALSO

L<exim(8)>, L<perlre(1)>, L<Exim|http://exim.org/>

=head1 AUTHOR

This  manual  page  was stitched together from spec.txt by Andreas Metzler L<ametzler at downhill.at.eu.org>
and updated by Heiko Schlittermann L<hs@schlittermann.de>.

=cut