oracular (3) User::pwent.3perl.gz

NAME

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

SYNOPSIS

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

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

        for (my ($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";
        }

        my $pw = getpw($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().

       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

HISTORY

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