1package User::pwent; 2 3use 5.006; 4 5use strict; 6use warnings; 7 8use Config; 9use Carp; 10 11our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS); 12BEGIN { 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} 31use vars grep /^\$pw_/, @EXPORT_OK; 32 33# 34# XXX: these mean somebody hacked this module's source 35# without understanding the underlying assumptions. 36# 37my $IE = "[INTERNAL ERROR]"; 38 39# Class::Struct forbids use of @ISA 40sub import { goto &Exporter::import } 41 42use Class::Struct qw(struct); 43struct 'User::pwent' => [ 44 name => '$', # 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. 73sub _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# 112sub 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 130sub _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 $pwob; 169} 170 171sub getpwent ( ) { _populate(CORE::getpwent()) } 172sub getpwnam ($) { _populate(CORE::getpwnam(shift)) } 173sub getpwuid ($) { _populate(CORE::getpwuid(shift)) } 174sub getpw ($) { ($_[0] =~ /^\d+\z/s) ? &getpwuid : &getpwnam } 175 176_feature_init(); 177 1781; 179__END__ 180 181=head1 NAME 182 183User::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 216This module's default exports override the core getpwent(), getpwuid(), 217and getpwnam() functions, replacing them with versions that return 218C<User::pwent> objects. This object has methods that return the 219similarly named structure field name from the C's passwd structure 220from F<pwd.h>, stripped of their leading "pw_" parts, namely C<name>, 221C<passwd>, C<uid>, C<gid>, C<change>, C<age>, C<quota>, C<comment>, 222C<class>, C<gecos>, C<dir>, C<shell>, and C<expire>. The C<passwd>, 223C<gecos>, and C<shell> fields are tainted when running in taint mode. 224 225You may also import all the structure fields directly into your 226namespace as regular variables using the :FIELDS import tag. (Note 227that this still overrides your core functions.) Access these fields 228as variables named with a preceding C<pw_> in front their method 229names. Thus, C<< $passwd_obj->shell >> corresponds to $pw_shell 230if you import the fields. 231 232The getpw() function is a simple front-end that forwards 233a numeric argument to getpwuid() and the rest to getpwnam(). 234 235To access this functionality without the core overrides, pass the 236C<use> an empty import list, and then access function functions 237with their full qualified names. The built-ins are always still 238available via the C<CORE::> pseudo-package. 239 240=head2 System Specifics 241 242Perl believes that no machine ever has more than one of C<change>, 243C<age>, or C<quota> implemented, nor more than one of either 244C<comment> or C<class>. Some machines do not support C<expire>, 245C<gecos>, or allegedly, C<passwd>. You may call these methods 246no matter what machine you're on, but they return C<undef> if 247unimplemented. 248 249You may ask whether one of these was implemented on the system Perl 250was built on by asking the importable C<pw_has> function about them. 251This function returns true if all parameters are supported fields 252on the build platform, false if one or more were not, and raises 253an exception if you asked about a field that Perl never knows how 254to provide. Parameters may be in a space-separated string, or as 255separate arguments. If you pass no parameters, the function returns 256the list of C<struct pwd> fields supported by your build platform's 257C library, as a list in list context, or a space-separated string 258in scalar context. Note that just because your C library had 259a field doesn't necessarily mean that it's fully implemented on 260that system. 261 262Interpretation of the C<gecos> field varies between systems, but 263traditionally holds 4 comma-separated fields containing the user's 264full name, office location, work phone number, and home phone number. 265An C<&> in the gecos field should be replaced by the user's properly 266capitalized login C<name>. The C<shell> field, if blank, must be 267assumed to be F</bin/sh>. Perl does not do this for you. The 268C<passwd> is one-way hashed garble, not clear text, and may not be 269unhashed save by brute-force guessing. Secure systems use more a 270more secure hashing than DES. On systems supporting shadow password 271systems, Perl automatically returns the shadow password entry when 272called by a suitably empowered user, even if your underlying 273vendor-provided C library was too short-sighted to realize it should 274do this. 275 276See passwd(5) and getpwent(3) for details. 277 278=head1 NOTE 279 280While this class is currently implemented using the Class::Struct 281module to build a struct-like class, you shouldn't rely upon this. 282 283=head1 AUTHOR 284 285Tom Christiansen 286 287=head1 HISTORY 288 289=over 290 291=item March 18th, 2000 292 293Reworked internals to support better interface to dodgey fields 294than normal Perl function provides. Added pw_has() field. Improved 295documentation. 296 297=back 298