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Write man pages and do some misc cleanup on old files.

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Add more documentation to the README.
This commit is contained in:
Nicholas J. Kain
2011-07-13 02:30:10 -04:00
parent 2a1885bab4
commit 24db573005
8 changed files with 260 additions and 505 deletions
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ifchd/ChangeLog
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20040906
accept_conns() trivial correctness fix: EINTR return from accept should
force continue rather than break in handling loop.
fail_on_fdne() is now file_exists() with a slightly different API.
20040818
Use inet_aton rather than custom function; daemon.[ch] removed.
20040817
ifchd no longer logs a "FATAL - select returned an error!" when it
is -KILL'ed.
20040626
pending_exit is now static volatile sig_atomic_t rather than
static volatile int for pedantic correctness issues.
20040614
Added --interface (-i) option that allows one to restrict the
interfaces that ifchd clients are allowed to modify. I
reccomend that this flag be used to further mitigate the possible
effects of a compromised client. By default, all interfaces
may be modified by clients.
Minor cleanups.
Clear corresponding namesvrs and domains on socket disconnection.
20040613
Factor out Linux-specific code into linux.c.
Nameservers and search domains now tracked per-connection to
prevent races where a client could force a writeout of data
provided by another client.
Interface name now cleared on connection close.
Make all headers idempotent.
Minor improvements to error messages.
20040612
Removed iffd[] array; this change makes the state machine action
functions (perform_*) depend on less external state.
HOSTNAME command now supported; it is not enabled by default.
If you wish for remote daemons to be able to change the hostname
of the local machine, use the --hostname (-o) option.
20040610
Added MTU support.
20040609
Robustify so that suicide() isn't called at every possible failure.
Harmless failures will now simply print an error to the log. Risky
or severe errors still suicide().
20040608
Added support for resolv.conf, namely "nameserver" and "search" entries.
Make strlist more robust and paranoid.
20040607
Improved accept() code to be much more robust; it can now properly error
recover. I hope this will fix the elusive random-exit problem that
plagues machines running the 2.6 kernel.
Refactored dispatch_work() to be cleaner.

339
ifchd/LICENSE
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.TH IFCHD 8 2011-07-12 Linux "Linux Administrator's Manual"
.SH NAME
ifchd \- interface change daemon
.SH SYNOPSIS
.B ifchd
.RI [ OPTION ]...
.SH DESCRIPTION
The ifchd daemon changes network interface configuration information
(such as the IP address, broadcast address, subnet, etc) as well as
resolv.conf, the machine hostname, and other similar system configuration
bits on the request of authorized clients such as ndhc instances.
.SH OPTIONS
.TP
.BR \-d ,\ \-\-detach
Immediately fork into the background. This is the default behavior.
.TP
.BR \-n ,\ \-\-nodetach
Do not fork into the background. Useful for debugging or initial setup.
.TP
.BR \-q ,\ \-\-quiet
Don't print to standard out, standard error, or syslog.
.TP
.BI \-c\ CHROOTDIR ,\ \-\-chroot= CHROOTDIR
This option specifies the directory to which ifchd should confine itself via
chroot() after startup. This directory should be shared with associated ndhc
daemons, and should have access to dev/urandom and dev/null. For logging to
work, a dev/log socket or device should also exist.
.TP
.BI \-r\ RESOLVCONF ,\ \-\-resolve= RESOLVCONF
Specifies the path to the system resolv.conf. This file will typically be in
/etc/resolv.conf. If this option is specified, ndhc will update the contents
of this file to match the DNS servers specified by the remote DHCP server. If
this option is not specified, ifchd will never change the system DNS resolution
configuration.
.TP
.BR \-o ,\ \-\-hostname
If specified, ifchd will update the system host name in response to any
hostname option field provided by a remote DHCP server on the request of
a ndhc client. If this option is not specified, ifchd will never change
the system hostname.
.TP
.BI \-p\ PIDFILE ,\ \-\-pidfile= PIDFILE
Write the process id number of the ifchd instance into the specified file name.
The default is to not write the process id number into any file at all.
.TP
.BI \-u\ USER ,\ \-\-user= USER
This option specifies the user name or user id that ifchd will change to after
startup. This user should be unique to the ifchd daemon.
.TP
.BI \-g\ GROUP ,\ \-\-group= GROUP
This option specifies the group name or group id that ifchd will change to
after startup.
.TP
.BI \-U\ CLIENTUSER ,\ \-\-cuser= CLIENTUSER
This option specifies the user name or user id that will be required of
processes that wish to make interface change requests of ifchd. Any other
users will be denied a connection to the ifchange socket.
.TP
.BI \-G\ CLIENTGROUP ,\ \-\-cgroup= CLIENTGROUP
This option specifies the group name or group id that will be required of
processes that wish to make interface change requests of ifchd. Any other
groups will be denied a connection to the ifchange socket.
.TP
.BI \-P\ CLIENTPID ,\ \-\-cpid= CLIENTPID
This option specifies the process id that will be required to make interface
change requests of ifchd. Any process that has a process id that does not
equal this value will be denied a connection to the ifchange socket.
.TP
.BI \-i\ INTERFACE ,\ \-\-interface= INTERFACE
Specifies an interface by name (such as 'eth0') on which ifchd is allowed to
make configuration changes (such as IP address, subnet mask, etc). Multiple
interfaces may be whitelisted by using this switch multiple times.
.TP
.BR \-V ,\ \-\-verbose
Print detailed messages. Useful for debugging or setup.
.TP
.BR \-h ,\ \-\-help
Print basic help information and exit.
.TP
.BR \-v ,\ \-\-version
Display the ifchd version number and copyright information.
.SH SIGNALS
It is not necessary to sleep between sending signals, as signals received are
processed sequentially in the order they are received. ifchd does not
perform any unusual behavior on receipt of signals.
.SH NOTES
ifchd is rather minimal and doesn't do exotic things like change NTP server
configuration. This is intentional, since it needs to run as CAP_NET_ADMIN,
which although far less powerful than root, still gives it a fair amount
of privileged behavior.