lib/perl5/5.6.1/User/pwent.pm

   1 package User::pwent;
   2
   3 use 5.006;
   4
   5 use strict;
   6 use warnings;
   7
   8 use Config;
   9 use Carp;
  10
  11 our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS);
  12 BEGIN {
  13     use Exporter   ();
  14     @EXPORT      = qw(getpwent getpwuid getpwnam getpw);
  15     @EXPORT_OK   = qw(
  16                         pw_has
  17
  18                         $pw_name    $pw_passwd  $pw_uid  $pw_gid
  19                         $pw_gecos   $pw_dir     $pw_shell
  20                         $pw_expire  $pw_change  $pw_class
  21                         $pw_age
  22                         $pw_quota   $pw_comment
  23                         $pw_expire
  24
  25                    );
  26     %EXPORT_TAGS = (
  27         FIELDS => [ grep(/^\$pw_/, @EXPORT_OK), @EXPORT ],
  28         ALL    => [ @EXPORT, @EXPORT_OK ],
  29     );
  30 }
  31 use vars grep /^\$pw_/, @EXPORT_OK;
  32
  33 #
  34 # XXX: these mean somebody hacked this module's source
  35 #      without understanding the underlying assumptions.
  36 #
  37 my $IE = "[INTERNAL ERROR]";
  38
  39 # Class::Struct forbids use of @ISA
  40 sub import { goto &Exporter::import }
  41
  42 use Class::Struct qw(struct);
  43 struct 'User::pwent' => [
  44     name    => '$',         # pwent[0]
  45     passwd  => '$',         # pwent[1]
  46     uid     => '$',         # pwent[2]
  47     gid     => '$',         # pwent[3]
  48
  49     # you'll only have one/none of these three
  50     change  => '$',         # pwent[4]
  51     age     => '$',         # pwent[4]
  52     quota   => '$',         # pwent[4]
  53
  54     # you'll only have one/none of these two
  55     comment => '$',         # pwent[5]
  56     class   => '$',         # pwent[5]
  57
  58     # you might not have this one
  59     gecos   => '$',         # pwent[6]
  60
  61     dir     => '$',         # pwent[7]
  62     shell   => '$',         # pwent[8]
  63
  64     # you might not have this one
  65     expire  => '$',         # pwent[9]
  66
  67 ];
  68
  69
  70 # init our groks hash to be true if the built platform knew how
  71 # to do each struct pwd field that perl can ever under any circumstances
  72 # know about.  we do not use /^pw_?/, but just the tails.
  73 sub _feature_init {
  74     our %Groks;         # whether build system knew how to do this feature
  75     for my $feep ( qw{
  76                          pwage      pwchange   pwclass    pwcomment
  77                          pwexpire   pwgecos    pwpasswd   pwquota
  78                      }
  79                  )
  80     {
  81         my $short = $feep =~ /^pw(.*)/
  82                   ? $1
  83                   : do {
  84                         # not cluck, as we know we called ourselves,
  85                         # and a confession is probably imminent anyway
  86                         warn("$IE $feep is a funny struct pwd field");
  87                         $feep;
  88                     };
  89
  90         exists $Config{ "d_" . $feep }
  91             || confess("$IE Configure doesn't d_$feep");
  92         $Groks{$short} = defined $Config{ "d_" . $feep };
  93     }
  94     # assume that any that are left are always there
  95     for my $feep (grep /^\$pw_/s, @EXPORT_OK) {
  96         $feep =~ /^\$pw_(.*)/;
  97         $Groks{$1} = 1 unless defined $Groks{$1};
  98     }
  99 }
 100
 101 # With arguments, reports whether one or more fields are all implemented
 102 # in the build machine's struct pwd pw_*.  May be whitespace separated.
 103 # We do not use /^pw_?/, just the tails.
 104 #
 105 # Without arguments, returns the list of fields implemented on build
 106 # machine, space separated in scalar context.
 107 #
 108 # Takes exception to being asked whether this machine's struct pwd has
 109 # a field that Perl never knows how to provide under any circumstances.
 110 # If the module does this idiocy to itself, the explosion is noisier.
 111 #
 112 sub pw_has {
 113     our %Groks;         # whether build system knew how to do this feature
 114     my $cando = 1;
 115     my $sploder = caller() ne __PACKAGE__
 116                     ? \&croak
 117                     : sub { confess("$IE @_") };
 118     if (@_ == 0) {
 119         my @valid = sort grep { $Groks{$_} } keys %Groks;
 120         return wantarray ? @valid : "@valid";
 121     }
 122     for my $feep (map { split } @_) {
 123         defined $Groks{$feep}
 124             || $sploder->("$feep is never a valid struct pwd field");
 125         $cando &&= $Groks{$feep};
 126     }
 127     return $cando;
 128 }
 129
 130 sub _populate (@) {
 131     return unless @_;
 132     my $pwob = new();
 133
 134     # Any that haven't been pw_had are assumed on "all" platforms of
 135     # course, this may not be so, but you can't get here otherwise,
 136     # since the underlying core call already took exception to your
 137     # impudence.
 138
 139     $pw_name    = $pwob->name   ( $_[0] );
 140     $pw_passwd  = $pwob->passwd ( $_[1] )   if pw_has("passwd");
 141     $pw_uid     = $pwob->uid    ( $_[2] );
 142     $pw_gid     = $pwob->gid    ( $_[3] );
 143
 144     if (pw_has("change")) {
 145         $pw_change      = $pwob->change ( $_[4] );
 146     }
 147     elsif (pw_has("age")) {
 148         $pw_age         = $pwob->age    ( $_[4] );
 149     }
 150     elsif (pw_has("quota")) {
 151         $pw_quota       = $pwob->quota  ( $_[4] );
 152     }
 153
 154     if (pw_has("class")) {
 155         $pw_class       = $pwob->class  ( $_[5] );
 156     }
 157     elsif (pw_has("comment")) {
 158         $pw_comment     = $pwob->comment( $_[5] );
 159     }
 160
 161     $pw_gecos   = $pwob->gecos  ( $_[6] ) if pw_has("gecos");
 162
 163     $pw_dir     = $pwob->dir    ( $_[7] );
 164     $pw_shell   = $pwob->shell  ( $_[8] );
 165
 166     $pw_expire  = $pwob->expire ( $_[9] ) if pw_has("expire");
 167
 168     return $pwob;
 169 }
 170
 171 sub getpwent ( ) { _populate(CORE::getpwent()) }
 172 sub getpwnam ($) { _populate(CORE::getpwnam(shift)) }
 173 sub getpwuid ($) { _populate(CORE::getpwuid(shift)) }
 174 sub getpw    ($) { ($_[0] =~ /^\d+\z/s) ? &getpwuid : &getpwnam }
 175
 176 _feature_init();
 177
 178 1;
 179 __END__
 180
 181 =head1 NAME
 182
 183 User::pwent - by-name interface to Perl's built-in getpw*() functions
 184
 185 =head1 SYNOPSIS
 186
 187  use User::pwent;
 188  $pw = getpwnam('daemon')       || die "No daemon user";
 189  if ( $pw->uid == 1 && $pw->dir =~ m#^/(bin|tmp)?\z#s ) {
 190      print "gid 1 on root dir";
 191  }
 192
 193  $real_shell = $pw->shell || '/bin/sh';
 194
 195  for (($fullname, $office, $workphone, $homephone) =
 196         split /\s*,\s*/, $pw->gecos)
 197  {
 198     s/&/ucfirst(lc($pw->name))/ge;
 199  }
 200
 201  use User::pwent qw(:FIELDS);
 202  getpwnam('daemon')             || die "No daemon user";
 203  if ( $pw_uid == 1 && $pw_dir =~ m#^/(bin|tmp)?\z#s ) {
 204      print "gid 1 on root dir";
 205  }
 206
 207  $pw = getpw($whoever);
 208
 209  use User::pwent qw/:DEFAULT pw_has/;
 210  if (pw_has(qw[gecos expire quota])) { .... }
 211  if (pw_has("name uid gid passwd"))  { .... }
 212  print "Your struct pwd has: ", scalar pw_has(), "\n";
 213
 214 =head1 DESCRIPTION
 215
 216 This module's default exports override the core getpwent(), getpwuid(),
 217 and getpwnam() functions, replacing them with versions that return
 218 C<User::pwent> objects.  This object has methods that return the
 219 similarly named structure field name from the C's passwd structure
 220 from F<pwd.h>, stripped of their leading "pw_" parts, namely C<name>,
 221 C<passwd>, C<uid>, C<gid>, C<change>, C<age>, C<quota>, C<comment>,
 222 C<class>, C<gecos>, C<dir>, C<shell>, and C<expire>.  The C<passwd>,
 223 C<gecos>, and C<shell> fields are tainted when running in taint mode.
 224
 225 You may also import all the structure fields directly into your
 226 namespace as regular variables using the :FIELDS import tag.  (Note
 227 that this still overrides your core functions.)  Access these fields
 228 as variables named with a preceding C<pw_> in front their method
 229 names.  Thus, C<< $passwd_obj->shell >> corresponds to $pw_shell
 230 if you import the fields.
 231
 232 The getpw() function is a simple front-end that forwards
 233 a numeric argument to getpwuid() and the rest to getpwnam().
 234
 235 To access this functionality without the core overrides, pass the
 236 C<use> an empty import list, and then access function functions
 237 with their full qualified names.  The built-ins are always still
 238 available via the C<CORE::> pseudo-package.
 239
 240 =head2 System Specifics
 241
 242 Perl believes that no machine ever has more than one of C<change>,
 243 C<age>, or C<quota> implemented, nor more than one of either
 244 C<comment> or C<class>.  Some machines do not support C<expire>,
 245 C<gecos>, or allegedly, C<passwd>.  You may call these methods
 246 no matter what machine you're on, but they return C<undef> if
 247 unimplemented.
 248
 249 You may ask whether one of these was implemented on the system Perl
 250 was built on by asking the importable C<pw_has> function about them.
 251 This function returns true if all parameters are supported fields
 252 on the build platform, false if one or more were not, and raises
 253 an exception if you asked about a field that Perl never knows how
 254 to provide.  Parameters may be in a space-separated string, or as
 255 separate arguments.  If you pass no parameters, the function returns
 256 the list of C<struct pwd> fields supported by your build platform's
 257 C library, as a list in list context, or a space-separated string
 258 in scalar context.  Note that just because your C library had
 259 a field doesn't necessarily mean that it's fully implemented on
 260 that system.
 261
 262 Interpretation of the C<gecos> field varies between systems, but
 263 traditionally holds 4 comma-separated fields containing the user's
 264 full name, office location, work phone number, and home phone number.
 265 An C<&> in the gecos field should be replaced by the user's properly
 266 capitalized login C<name>.  The C<shell> field, if blank, must be
 267 assumed to be F</bin/sh>.  Perl does not do this for you.  The
 268 C<passwd> is one-way hashed garble, not clear text, and may not be
 269 unhashed save by brute-force guessing.  Secure systems use more a
 270 more secure hashing than DES.  On systems supporting shadow password
 271 systems, Perl automatically returns the shadow password entry when
 272 called by a suitably empowered user, even if your underlying
 273 vendor-provided C library was too short-sighted to realize it should
 274 do this.
 275
 276 See passwd(5) and getpwent(3) for details.
 277
 278 =head1 NOTE
 279
 280 While this class is currently implemented using the Class::Struct
 281 module to build a struct-like class, you shouldn't rely upon this.
 282
 283 =head1 AUTHOR
 284
 285 Tom Christiansen
 286
 287 =head1 HISTORY
 288
 289 =over
 290
 291 =item March 18th, 2000
 292
 293 Reworked internals to support better interface to dodgey fields
 294 than normal Perl function provides.  Added pw_has() field.  Improved
 295 documentation.
 296
 297 =back