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

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

NNAAMMEE #

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

SSYYNNOOPPSSIISS #

  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";

DDEESSCCRRIIPPTTIIOONN #

 This module's default exports override the core ggeettppwweenntt(()), ggeettppwwuuiidd(()),
 and ggeettppwwnnaamm(()) 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 _p_w_d_._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 ggeettppww(()) function is a simple front-end that forwards a numeric
 argument to ggeettppwwuuiidd(()) and the rest to ggeettppwwnnaamm(()).

 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.

SSyysstteemm SSppeecciiffiiccss 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
 _/_b_i_n_/_s_h.  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 ppaasssswwdd(5) and ggeettppwweenntt(3) for details.

NNOOTTEE #

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

AAUUTTHHOORR #

 Tom Christiansen

HHIISSTTOORRYY #

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

perl v5.36.3 2019-02-13 User::pwent(3p)