Perl腳本寫輸出兩次； 第二次以相反的順序

Question

我試圖弄清楚一個腳本為什么兩次寫輸出。 第一次以正確的順序，第二次以相反的順序。 它應該只編寫一次。

#!/usr/bin/perl


use warnings;
use strict;
use Fcntl ':mode';
use File::Find;
no warnings 'File::Find';
no warnings 'uninitialized';

my $dir = "/var/log/tivoli/";
my $mtab = "/etc/mtab";
my $permFile = "world_writable_files.txt";
my $tmpFile = "world_writable_files.tmp";
my $exclude = "/usr/local/etc/world_writable_excludes.txt";
my $mask = S_IWUSR | S_IWGRP | S_IWOTH;
my (%excludes, %devNums);
my $errHeader;

# Compile a list of mountpoints that need to be scanned
my @mounts;

open MT, "<${mtab}" or die "Cannot open ${mtab}, $!";

# We only want the local mountpoints
while (<MT>) {
  if ($_ =~ /ext[34]/) {
    chomp;
    my @line = split;
    push(@mounts, $line[1]);
    my @stats = stat($line[1]);
    $devNums{$stats[0]} = undef;
  }
}

close MT;

# Build a hash from /usr/local/etc/world_writables_excludes.txt
if ((! -e $exclude) || (-z $exclude)) {
  $errHeader = <<HEADER;
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!                                                  !!
!! /usr/local/etc/world_writable_excludes.txt is    !!
!! is missing or empty. This report includes        !!
!! every world-writable file including those which  !!
!! are expected and should be excluded.             !!
!!                                                  !!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


HEADER

} else {
  open XCLD, "<${exclude}" or die "Cannot open ${exclude}, $!\n";
  while (<XCLD>) {
    chomp;
    $excludes{$_} = 1;
  }
}

sub wanted {
  my @dirStats = stat($File::Find::name);

  # Is it excluded from the report...
  return if exists $excludes{$File::Find::name};

  # ...is the Tivoli installation directory or a special directory...
  if ($File::Find::name =~ m{^/sys|^/proc|^/dev|^/opt/IBM/ITM}) {
    $File::Find::prune = 1;
    return;
  }

  # ...a regular file, ...
  return unless -f;

  # ...local, ...
  return unless (exists $devNums{$dirStats[0]});

  # ...and world writable?
  return unless ($dirStats[2] & $mask) == $mask;

  # If so, add the file to the list of world writable files
  print(WWFILE "$File::Find::name\n");

}

# Create the output file path if it doesn't already exist.
mkdir($dir or die "Cannot execute mkdir on ${dir}, $!") unless (-d $dir);

# Create our filehandle for writing our findings
open WWFILE, ">${dir}${tmpFile}" or die "Cannot open ${dir}${tmpFile}, $!";
print(WWFILE "${errHeader}") if ($errHeader);

find(\&wanted, @mounts);

close WWFILE;

# If no world-writable files have been found ${tmpFile} should be zero-size;
# Delete it so Tivoli won't alert
if (-z "${dir}${tmpFile}") {
  unlink "${dir}${tmpFile}";

} else {
  rename("${dir}${tmpFile}","${dir}${permFile}") or die "Cannot rename file ${dir}${tmpFile}, $!";

}

輸出示例：

# cat world_writable_files.txt 
/var/opt/ds_agent/am/diagnostic_1.log
/home/User1/report.pl.20130220
/home/User1/report.pl.20130220
/var/opt/ds_agent/am/diagnostic_1.log

每個文件在腳本中只被寫入一次，所以我想知道文件系統是否被掃描了兩次。 每個方向一次。 我看不到會發生什么，但我不知道。

排除文件：

# cat /usr/local/etc/world_writable_excludes.txt 
/var/opt/ds_agent/diagnostic.log
/var/opt/ds_agent/am/diagnostic.log

對這個難題有什么想法嗎？

Answer 1

這是因為@mounts除了/home和/var之外還具有/ 。 因此，您要求它掃描/以及以下的所有內容（包括/home和/var ），然后掃描/home以及以下的所有內容，然后掃描/var以及以下的所有內容。

最好確定要避開的地方。

while (<MT>) {
   my @fields = split;
   if ($field[2] !~ /^ext[34]\z/) {
      ++$excludes{ $fields[1] };
   }
}

find(\&wanted, '/');

sub wanted {
   if ($excludes{$File::Find::name}) {
      $File::Find::prune = 1;
      return;
   }

   my @dirStats = stat($File::Find::name);

   return if !-f;
   return if $dirStats[2] & S_IWOTH;

   print(WWFILE "$File::Find::name\n");
}

您不再需要if ($File::Find::name =~ m{^/sys|^/proc|^/dev|^/opt/IBM/ITM}) ，因為它們不是ext3或ext4。 /opt/IBM/ITM可能除外（因為我不知道那是什么）。 如果確實有一些要跳過的文件或目錄，請將其添加到%excludes而不要進行相對昂貴的正則表達式匹配。

++$excludes{$_} for qw( /foo /bar /opt/IBM/ITM );