glibc/hesiod
Joseph Myers a5f891ac8d Consistently include Makeconfig after defining subdir.
In <https://sourceware.org/ml/libc-alpha/2014-01/msg00196.html> I
noted it was necessary to add includes of Makeconfig early in various
subdirectory makefiles for the tests-special variable settings added
by that patch to be conditional on configuration information.  No-one
commented on the general question there of whether Makeconfig should
always be included immediately after the definition of subdir.

This patch implements that early inclusion of Makeconfig in each
directory (which is a lot easier than consistent placement of includes
of Rules).  Includes are added if needed, or moved up if already
present.  Subdirectory "all:" targets are removed, since Makeconfig
provides one.

There is potential for further cleanups I haven't done.  Rules and
Makerules have code such as

ifneq   "$(findstring env,$(origin headers))" ""
headers :=
endif

to override to empty any value of various variables that came from the
environment.  I think there is a case for Makeconfig setting all the
subdirectory variables (other than subdir) to empty to ensure no
outside value is going to take effect if a subdirectory fails to
define a variable.  (A list of such variables, possibly out of date
and incomplete, is in manual/maint.texi.)  Rules and Makerules would
give errors if Makeconfig hadn't already been included, instead of
including it themselves.  The special code to override values coming
from the environment would then be obsolete and could be removed.

Tested x86_64, including that installed binaries are identical before
and after the patch.

	* argp/Makefile: Include Makeconfig immediately after defining
	subdir.
	* assert/Makefile: Likewise.
	* benchtests/Makefile: Likewise.
	* catgets/Makefile: Likewise.
	* conform/Makefile: Likewise.
	* crypt/Makefile: Likewise.
	* csu/Makefile: Likewise.
	(all): Remove target.
	* ctype/Makefile: Include Makeconfig immediately after defining
	subdir.
	* debug/Makefile: Likewise.
	* dirent/Makefile: Likewise.
	* dlfcn/Makefile: Likewise.
	* gmon/Makefile: Likewise.
	* gnulib/Makefile: Likewise.
	* grp/Makefile: Likewise.
	* gshadow/Makefile: Likewise.
	* hesiod/Makefile: Likewise.
	* hurd/Makefile: Likewise.
	(all): Remove target.
	* iconvdata/Makefile: Include Makeconfig immediately after
	defining subdir.
	* inet/Makefile: Likewise.
	* intl/Makefile: Likewise.
	* io/Makefile: Likewise.
	* libio/Makefile: Likewise.
	(all): Remove target.
	* locale/Makefile: Include Makeconfig immediately after defining
	subdir.
	* login/Makefile: Likewise.
	* mach/Makefile: Likewise.
	(all): Remove target.
	* malloc/Makefile: Include Makeconfig immediately after defining
	subdir.
	(all): Remove target.
	* manual/Makefile: Include Makeconfig immediately after defining
	subdir.
	* math/Makefile: Likewise.
	* misc/Makefile: Likewise.
	* nis/Makefile: Likewise.
	* nss/Makefile: Likewise.
	* po/Makefile: Likewise.
	(all): Remove target.
	* posix/Makefile: Include Makeconfig immediately after defining
	subdir.
	* pwd/Makefile: Likewise.
	* resolv/Makefile: Likewise.
	* resource/Makefile: Likewise.
	* rt/Makefile: Likewise.
	* setjmp/Makefile: Likewise.
	* shadow/Makefile: Likewise.
	* signal/Makefile: Likewise.
	* socket/Makefile: Likewise.
	* soft-fp/Makefile: Likewise.
	* stdio-common/Makefile: Likewise.
	* stdlib/Makefile: Likewise.
	* streams/Makefile: Likewise.
	* string/Makefile: Likewise.
	* sunrpc/Makefile: Likewise.
	(all): Remove target.
	* sysvipc/Makefile: Include Makeconfig immediately after defining
	subdir.
	* termios/Makefile: Likewise.
	* time/Makefile: Likewise.
	* timezone/Makefile: Likewise.
	(all): Remove target.
	* wcsmbs/Makefile: Include Makeconfig immediately after defining
	subdir.
	* wctype/Makefile: Likewise.

libidn/ChangeLog:
	* Makefile: Include Makeconfig immediately after defining subdir.

localedata/ChangeLog:
	* Makefile: Include Makeconfig immediately after defining subdir.
	(all): Remove target.

nptl/ChangeLog:
	* Makefile: Include Makeconfig immediately after defining subdir.

nptl_db/ChangeLog:
	* Makefile: Include Makeconfig immediately after defining subdir.
2014-02-26 23:12:03 +00:00
..
nss_hesiod Use glibc_likely instead __builtin_expect. 2014-02-10 15:07:12 +01:00
Depend Move nss directory into sysdeps Subdirs. 2013-02-05 14:32:48 -08:00
hesiod_p.h * hesiod/hesiod_p.h (struct hesiod_p): Add classes array. 2005-06-15 04:14:52 +00:00
hesiod.c Rename __secure_getenv to secure_getenv 2012-07-25 19:46:22 +02:00
hesiod.h Update. 2004-09-14 04:41:35 +00:00
Makefile Consistently include Makeconfig after defining subdir. 2014-02-26 23:12:03 +00:00
README.hesiod * hesiod/hesiod_p.h (struct hesiod_p): Add classes array. 2005-06-15 04:14:52 +00:00
Versions Update. 2002-02-01 23:24:05 +00:00

The GNU C library contains an NSS module for the Hesiod name service.
Hesiod is a general name service for a variety of applications and is
based on the Berkeley Internet Name Daemon (BIND).

Introduction
============

The Hesiod NSS module implements access to all relevant standard
Hesiod types, which means that Hesiod can be used for the `group',
`passwd' and `services' databases.  There is however a restriction.
In the same way that it is impossible to use `gethostent()' to iterate
over all the data provided by DNS, it is not possible to scan the
entire Hesiod database by means of `getgrent()', `getpwent()' and
`getservent()'.  Besides, Hesiod only provides support for looking up
services by name and not for looking them up by port.  In essence this
means that the Hesiod name service is only consulted as a result of
one of the following function calls:

  * getgrname(), getgrgid()
  * getpwname(), getpwuid()
  * getservbyname()

and their reentrant counterparts.


Configuring your systems
========================

Configuring your systems to make use the Hesiod name service requires
one or more of the following steps, depending on whether you are
already running Hesiod in your network.

Configuring NSS
---------------

First you should modify the file `/etc/nsswitch.conf' to tell
NSS for which database you want to use the Hesiod name service.  If
you want to use Hesiod for all databases it can handle your
configuration file could look like this:

  # /etc/nsswitch.conf
  #
  # Example configuration of GNU Name Service Switch functionality.
  #

  passwd:	  db files hesiod
  group:	  db files hesiod
  shadow:	  db files

  hosts:	  files dns
  networks:	  files dns

  protocols:	  db files
  services:	  db files hesiod
  ethers:	  db files
  rpc:		  db files

For more information on NSS, please refer to the `The GNU C Library
Reference Manual'.


Configuring Hesiod
------------------

Next, you will have to configure Hesiod.  If you are already running
Hesiod in your network, you probably already have a file named
`hesiod.conf' on your machines (probably as `/etc/hesiod.conf' or
`/usr/local/etc/hesiod.conf').  The Hesiod NSS module looks for
`/etc/hesiod.conf' by default.  If there is no configuration file you
will want to create your own.  It should look something like:

  rhs=.your.domain
  lhs=.ns
  classes=in,hs

The optional classes settings specifies which DNS classes Hesiod
should do lookups in.  Possible values are IN (the preferred class)
and  HS (the deprecated class, still used by some sites).
You may specify both classes separated by a comma to try one class
first and then the other if no entry is available in the first
class.  The default value of the classes variable is `IN,HS'.

The value of rhs can be overridden by the environment variable
`HES_DOMAIN'.

Configuring your name servers
-----------------------------

In addition, if you are not already running Hesiod in your network,
you need to create Hesiod information on your central name servers.
You need to run `named' from BIND 4.9 or higher on these servers, and
make them authoritative for the domain `ns.your.domain' with a line in
`/etc/named.boot' reading something like:

  primary         ns.your.domain          named.hesiod

or if you are using the new BIND 8.1 or higher add something to
`/etc/named.conf' like:

  zone "ns.your.domain" {
          type master;
          file "named.hesiod";
  };

Then in the BIND working directory (usually `/var/named') create the
file `named.hesiod' containing data that looks something like:

  ; SOA and NS records.
  @       IN      SOA     server1.your.domain admin-address.your.domain (
                  40000           ; serial - database version number
                  1800            ; refresh - sec servers
                  300             ; retry - for refresh
                  3600000         ; expire - unrefreshed data
                  7200 )          ; min
                  NS      server1.your.domain
                  NS      server2.your.domain

  ; Actual Hesiod data.
  libc.group      TXT     "libc:*:123:gnu,gnat"
  123.gid         CNAME   libc.group
  gnu.passwd      TXT     "gnu:*:4567:123:GNU:/home/gnu:/bin/bash"
  456.uid         CNAME   mark.passwd
  nss.service     TXT     "nss tcp 789 switch sw "
  nss.service     TXT     "nss udp 789 switch sw"

where `libc' is an example of a group, `gnu' an example of an user,
and `nss' an example of a service.  Note that the format used to
describe services differs from the format used in `/etc/services'.
For more information on `named' refer to the `Name Server Operations
Guide for BIND' that is included in the BIND distribution.


Security
========

Note that the information stored in the Hesiod database in principle
is publicly available.  Care should be taken with including vulnerable
information like encrypted passwords in the Hesiod database.  There
are some ways to improve security by using features provided by
`named' (see the discussion about `secure zones' in the BIND
documentation), but one should keep in mind that Hesiod was never
intended to distribute passwords.  In the origional design
authenticating users was the job of the Kerberos service.


More information
================

For more information on the Hesiod name service take a look at some of
the papers in ftp://athena-dist.mit.edu:/pub/ATHENA/usenix and the
documentation that accompanies the source code for the Hesiod name
service library in ftp://athena-dist.mit.edu:/pub/ATHENA/hesiod.

There is a mailing list at MIT for Hesiod users, hesiod@mit.edu.  To
get yourself on or off the list, send mail to hesiod-request@mit.edu.