1 | #!/usr/bin/perl |
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2 | # |
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3 | # Perform sanity checks on the services file, supplied as argument. |
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4 | # Based on an earlier shell script of the same name, but much faster, |
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5 | # and it also detects actual errors in the current services file :) |
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6 | # |
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7 | # This program includes a manual, run "perldoc serviceslint" to see it. |
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8 | # |
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9 | |
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10 | use strict; |
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11 | use warnings; |
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12 | |
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13 | die "Usage: $0 /etc/services\n" unless $#ARGV == 0; |
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14 | |
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15 | # Build a hash of known protocols |
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16 | my %protocol; |
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17 | open FH, "protocols" or die "cannot open protocols: $!\n"; |
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18 | while (<FH>) { |
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19 | chomp; |
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20 | s/#.*$//; |
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21 | my ($name, $port) = m/([\S]+)\s+(\d+)/ or next; |
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22 | $protocol{$name} = $port; |
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23 | } |
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24 | close FH; |
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25 | |
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26 | # Parse the supplied services file |
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27 | my $retval = 0; |
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28 | my $line = 0; |
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29 | my %service; |
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30 | open FH, $ARGV[0] or die "cannot open $ARGV[0]: $!\n"; |
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31 | while (<FH>) { |
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32 | $line++; # Keep a line count |
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33 | chomp; # Remove CR/LF chars |
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34 | if (m/^\s+/) { |
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35 | print "Malformed line $line\n"; # No leading whitespace |
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36 | $retval = 1; |
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37 | next; |
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38 | } |
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39 | s/\s*#.*$//; # Strip out comments |
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40 | next if m/^$/; # Skip empty lines |
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41 | my ($name, $port, $proto, $aliases) = # Primary pattern match |
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42 | m/^([\S]+)\s+(\d+)\/(\w+)\s*(.*)/ |
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43 | or die "Malformed line: $line\n"; |
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44 | if (not exists $protocol{$proto}) { |
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45 | print "Bad protocol at line $line: $proto\n"; |
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46 | $retval = 1; |
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47 | } |
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48 | if (exists $service{$proto}{$port}) { |
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49 | print "Duplicate port at line $line: $port/$proto\n"; |
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50 | $retval = 1; |
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51 | } |
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52 | $service{$proto}{$port} = $name; |
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53 | foreach ($name, split /\s+/, $aliases) { |
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54 | if (exists $service{$proto}{$_}) { |
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55 | print "Duplicate name at line $line: $_/$proto\n"; |
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56 | $retval = 1; |
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57 | } |
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58 | $service{$proto}{$_} = $port; |
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59 | }; |
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60 | |
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61 | } |
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62 | close FH; |
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63 | exit $retval; |
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64 | |
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65 | __END__ |
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66 | |
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67 | =head1 NAME |
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68 | |
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69 | serviceslint - perform verification on the /etc/services file |
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70 | |
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71 | =head1 SYNOPSIS |
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72 | |
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73 | B<serviceslint> I<filename> |
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74 | |
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75 | =head1 DESCRIPTION |
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76 | |
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77 | The B<serviceslint> command performs syntax and content checks on the |
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78 | given filename, normally a copy of the I</etc/services> file. |
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79 | |
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80 | Syntax checking consists of a regular expression applied to |
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81 | non-empty, non-comment lines. If the syntax check fails, then |
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82 | the program prints a message and aborts with non-zero status code. |
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83 | |
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84 | Content checking detects various kinds of duplicate entries. |
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85 | Currently, warnings are printed for duplicate entries, but execution |
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86 | continues, and the program I<exits with status code zero> (eg. success). |
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87 | |
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88 | =over |
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89 | |
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90 | =item B<Malformed line> I<NNN> |
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91 | |
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92 | The specified line has invalid syntax. Note that leading whitespace |
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93 | is not permitted. Non-empty lines must begin with a comment, or with |
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94 | a service name followed by a port number / protocol pair. |
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95 | |
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96 | =item B<Duplicate port at line> I<NNN> |
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97 | |
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98 | Occurs when a port number / protocol pair is found more than once |
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99 | in the services file. The warning is flagged on the second (and any |
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100 | subsequent) occurrences. These entries will not be found via the |
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101 | B<getservbyport()> function. |
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102 | |
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103 | =item B<Duplicate name at line> I<NNN> |
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104 | |
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105 | Occurs when a service name, or alias, occurs more than once in the |
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106 | services file. The warning is flagged on the second (and subsequent) |
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107 | occurrence. These entries will not be returned by the B<getservbyname()> |
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108 | function. |
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109 | |
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110 | =back |
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111 | |
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112 | =head1 SEE ALSO |
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113 | |
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114 | The services(5) man page describes the file format. |
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115 | |
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116 | =head1 AUTHOR |
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117 | |
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118 | Ralph Siemsen & Phil Knirsch |
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119 | |
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