


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



perl v5.10.1                2002-10-27                          1





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


       To access this functionality without the core overrides,
       pass the "use" an empty import list, and then access
       function 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
       support "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
       provide.  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
       context, or a space-separated string in scalar context.
       Note that just because your C library had a field doesn't
       necessarily mean that it's fully implemented on that
       system.

       Interpretation of the "gecos" field varies between
       systems, 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
       capitalized 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 systems supporting shadow password systems,
       Perl automatically 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.

AUTHOR
       Tom Christiansen



perl v5.10.1                2002-10-27                          2





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


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




















































perl v5.10.1                2002-10-27                          3


