


User::pwent(3p)  Perl Programmers Reference Guide User::pwent(3p)


NAME
       User::pwent - by-name interface to Perl's built-in
       getpw*() functions

SYNOPSIS
        use User::pwent;
        $pw = getpwnam('daemon')       || die "No daemon user";
        if ( $pw->uid == 1 && $pw->dir =~ m#^/(bin|tmp)?\z#s ) {
            print "gid 1 on root dir";
        }

        $real_shell = $pw->shell || '/bin/sh';

        for (($fullname, $office, $workphone, $homephone) =
               split /\s*,\s*/, $pw->gecos)
        {
           s/&/ucfirst(lc($pw->name))/ge;
        }

        use User::pwent qw(:FIELDS);
        getpwnam('daemon')             || die "No daemon user";
        if ( $pw_uid == 1 && $pw_dir =~ m#^/(bin|tmp)?\z#s ) {
            print "gid 1 on root dir";
        }

        $pw = getpw($whoever);

        use User::pwent qw/:DEFAULT pw_has/;
        if (pw_has(qw[gecos expire quota])) { .... }
        if (pw_has("name uid gid passwd"))  { .... }
        print "Your struct pwd has: ", scalar pw_has(), "\n";


DESCRIPTION
       This module's default exports override the core getp-
       went(), getpwuid(), and getpwnam() functions, replacing
       them with versions that return "User::pwent" objects.
       This object has methods that return the similarly named
       structure field name from the C's passwd structure from
       pwd.h, stripped of their leading "pw_" parts, namely
       "name", "passwd", "uid", "gid", "change", "age", "quota",
       "comment", "class", "gecos", "dir", "shell", and "expire".
       The "passwd", "gecos", and "shell" fields are tainted when
       running in taint mode.

       You may also import all the structure fields directly into
       your namespace as regular variables using the :FIELDS
       import tag.  (Note that this still overrides your core
       functions.)  Access these fields as variables named with a
       preceding "pw_" in front their method names.  Thus,
       "$passwd_obj->shell" corresponds to $pw_shell if you
       import the fields.

       The getpw() function is a simple front-end that forwards a



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User::pwent(3p)  Perl Programmers Reference Guide User::pwent(3p)


       numeric argument to getpwuid() and the rest to getpwnam().

       To access this functionality without the core overrides,
       pass the "use" an empty import list, and then access func-
       tion functions with their full qualified names.  The
       built-ins are always still available via the "CORE::"
       pseudo-package.

       System Specifics

       Perl believes that no machine ever has more than one of
       "change", "age", or "quota" implemented, nor more than one
       of either "comment" or "class".  Some machines do not sup-
       port "expire", "gecos", or allegedly, "passwd".  You may
       call these methods no matter what machine you're on, but
       they return "undef" if unimplemented.

       You may ask whether one of these was implemented on the
       system Perl was built on by asking the importable "pw_has"
       function about them.  This function returns true if all
       parameters are supported fields on the build platform,
       false if one or more were not, and raises an exception if
       you asked about a field that Perl never knows how to pro-
       vide.  Parameters may be in a space-separated string, or
       as separate arguments.  If you pass no parameters, the
       function returns the list of "struct pwd" fields supported
       by your build platform's C library, as a list in list con-
       text, or a space-separated string in scalar context.  Note
       that just because your C library had a field doesn't nec-
       essarily mean that it's fully implemented on that system.

       Interpretation of the "gecos" field varies between sys-
       tems, but traditionally holds 4 comma-separated fields
       containing the user's full name, office location, work
       phone number, and home phone number.  An "&" in the gecos
       field should be replaced by the user's properly capital-
       ized login "name".  The "shell" field, if blank, must be
       assumed to be /bin/sh.  Perl does not do this for you.
       The "passwd" is one-way hashed garble, not clear text, and
       may not be unhashed save by brute-force guessing.  Secure
       systems use more a more secure hashing than DES.  On sys-
       tems supporting shadow password systems, Perl automati-
       cally returns the shadow password entry when called by a
       suitably empowered user, even if your underlying vendor-
       provided C library was too short-sighted to realize it
       should do this.

       See passwd(5) and getpwent(3) for details.

NOTE
       While this class is currently implemented using the
       Class::Struct module to build a struct-like class, you
       shouldn't rely upon this.




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User::pwent(3p)  Perl Programmers Reference Guide User::pwent(3p)


AUTHOR
       Tom Christiansen

HISTORY
       March 18th, 2000
           Reworked internals to support better interface to
           dodgey fields than normal Perl function provides.
           Added pw_has() field.  Improved documentation.

















































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