User::pwent - by-name interface to Perl's built-in getpw*() functions
- 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";
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.
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.
While this class is currently implemented using the Class::Struct module to build a struct-like class, you shouldn't rely upon this.
Tom Christiansen