Question

我试图弄清楚脚本为什么要两次写输出。第一次按正确顺序，第二次按相反顺序排列。它应该只写一次。

#!/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}, $!";

}

示例输出：

# 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

每个文件只在脚本中写入一次，所以我想知道文件系统是否被扫描两次。一次在每个方向。我不知道会发生什么，但我不知道。

排除档案：

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

对这个难题的任何想法？

Answer 1

这是因为@mounts除了/和/home之外还有/var。因此，您要求它扫描/处的所有内容（包括/home和/var），然后扫描/home处及之下的所有内容，然后扫描所有内容低于/var。

最好找出你想要避免的地方。

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");
}

你不再需要if ($File::Find::name =~ m{^/sys|^/proc|^/dev|^/opt/IBM/ITM})，因为它们不是ext3或ext4。除了/opt/IBM/ITM之外（因为我不知道那是什么）。如果您确实有一些想跳过的文件或目录，请将它们添加到%excludes，而不是进行相对昂贵的正则表达式匹配。

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

Perl脚本编写输出两次;第二次以相反的顺序

1 个答案: