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1 package User::pwent;
3 use 5.006;
5 use strict;
6 use warnings;
8 use Config;
9 use Carp;
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
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
26 %EXPORT_TAGS = (
27 FIELDS => [ grep(/^\$pw_/, @EXPORT_OK), @EXPORT ],
28 ALL => [ @EXPORT, @EXPORT_OK ],
31 use vars grep /^\$pw_/, @EXPORT_OK;
34 # XXX: these mean somebody hacked this module's source
35 # without understanding the underlying assumptions.
37 my $IE = "[INTERNAL ERROR]";
39 # Class::Struct forbids use of @ISA
40 sub import { goto &Exporter::import }
42 use Class::Struct qw(struct);
43 struct 'User::pwent' => [
44 name => '$', # pwent[0]
45 passwd => '$', # pwent[1]
46 uid => '$', # pwent[2]
47 gid => '$', # pwent[3]
49 # you'll only have one/none of these three
50 change => '$', # pwent[4]
51 age => '$', # pwent[4]
52 quota => '$', # pwent[4]
54 # you'll only have one/none of these two
55 comment => '$', # pwent[5]
56 class => '$', # pwent[5]
58 # you might not have this one
59 gecos => '$', # pwent[6]
61 dir => '$', # pwent[7]
62 shell => '$', # pwent[8]
64 # you might not have this one
65 expire => '$', # pwent[9]
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
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;
90 exists $Config{ "d_" . $feep }
91 || confess("$IE Configure doesn't d_$feep");
92 $Groks{$short} = defined $Config{ "d_" . $feep };
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};
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.
105 # Without arguments, returns the list of fields implemented on build
106 # machine, space separated in scalar context.
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.
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";
122 for my $feep (map { split } @_) {
123 defined $Groks{$feep}
124 || $sploder->("$feep is never a valid struct pwd field");
125 $cando &&= $Groks{$feep};
127 return $cando;
130 sub _populate (@) {
131 return unless @_;
132 my $pwob = new();
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.
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] );
144 if (pw_has("change")) {
145 $pw_change = $pwob->change ( $_[4] );
147 elsif (pw_has("age")) {
148 $pw_age = $pwob->age ( $_[4] );
150 elsif (pw_has("quota")) {
151 $pw_quota = $pwob->quota ( $_[4] );
154 if (pw_has("class")) {
155 $pw_class = $pwob->class ( $_[5] );
157 elsif (pw_has("comment")) {
158 $pw_comment = $pwob->comment( $_[5] );
161 $pw_gecos = $pwob->gecos ( $_[6] ) if pw_has("gecos");
163 $pw_dir = $pwob->dir ( $_[7] );
164 $pw_shell = $pwob->shell ( $_[8] );
166 $pw_expire = $pwob->expire ( $_[9] ) if pw_has("expire");
168 return $pwob;
171 sub getpwent ( ) { _populate(CORE::getpwent()) }
172 sub getpwnam ($) { _populate(CORE::getpwnam(shift)) }
173 sub getpwuid ($) { _populate(CORE::getpwuid(shift)) }
174 sub getpw ($) { ($_[0] =~ /^\d+\z/s) ? &getpwuid : &getpwnam }
176 _feature_init();
179 __END__
181 =head1 NAME
183 User::pwent - by-name interface to Perl's built-in getpw*() functions
185 =head1 SYNOPSIS
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";
193 $real_shell = $pw->shell || '/bin/sh';
195 for (($fullname, $office, $workphone, $homephone) =
196 split /\s*,\s*/, $pw->gecos)
198 s/&/ucfirst(lc($pw->name))/ge;
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";
207 $pw = getpw($whoever);
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";
214 =head1 DESCRIPTION
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.
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.
232 The getpw() function is a simple front-end that forwards
233 a numeric argument to getpwuid() and the rest to getpwnam().
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.
240 =head2 System Specifics
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.
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.
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.
276 See passwd(5) and getpwent(3) for details.
278 =head1 NOTE
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.
283 =head1 AUTHOR
285 Tom Christiansen
287 =head1 HISTORY
289 =over
291 =item March 18th, 2000
293 Reworked internals to support better interface to dodgey fields
294 than normal Perl function provides. Added pw_has() field. Improved
295 documentation.
297 =back