Rod, Jordan and David have more or less given me the OK on this
with the understanding that it doesn't change any functionality.
It doesn't: these are bug fixes only. No other part of the system
should be affected. Of course, since I'm the only one working on
NIS, you'll just have to take my word on it. :)
Fixes for the following annoyingly subtle bugs:
- ypbindproc_setdom_2 is supposed to be declared void *, not boot_t *,
and it fails to correctly signal failures back to the ypset(8) command:
we need to call one of the svcerr_*() functions (in this case,
svcerr_noprog() seems a logical choice -- we're really cheating
a bit here because nothing else quite fits) to tell ypset that the
attempt to set the binding for a domain failed. If we don't do this,
failed ypset attempts either appear (incorrectly) to succeed, or
they time out.
- The lock handling for child processes isn't quite right. The
child broadcaster processes have to release all locks on the
binding files and the ypbind.lock file.
- The parent ypbind process will SEGV if you do the following:
-- start ypbind with the -ypset or -ypsetme flag
-- type 'ypwhich -d random_unserved_domain'
-- type 'ypset -d random_unserved_domain anyhost'
-- type 'ypwhich -d random_unserved_domain' again
-- wait about 60 seconds
What happens is this: the ypwhich command causes ypbind to fork a
broadcaster process that searches for a server for random_unserved_domain.
If you then use ypset to force a binding while this process is still alive,
the state flags that tell the ypbind parent process that the child
is running will be cleared. The second ypwhich command then causes
a *second* child process to be forked for random_unserved_domain,
which is verbotten. When the first broadcaster exits and tells the
parent that it wasn't able to find a server for the domain, the parent
clobbers the entry for random_unserved_domain. Then the second broadcaster
exits and the same thing happens, only trying to clobber the entry
twice causes a SEGV.
The fix for this is a slight change in program structure: since we
can't have more than one broadcaster for a given domain at a time,
we save the pipe descriptors and pid for the child broadcaster in members
of the _dom_binding struct for the domain. (As a side effect, we
can get rid of the global child_fds variable.) So when rpc_received()
finds that it's been asked to do a ypset for a domain for which a
broadcaster process exists, it sends a SIGINT to the child to kill it
and closes the pipe to the now-dead child. This keeps everything in sync
and insures that we don't leak file descriptors.
- ping() should be using YPPROC_DOMAIN rather than YPPROC_DOMAIN_NONACK
when it does its clnt_call() to the server.
- Removed the check for client_handle == NULL in ping() and make
client_handle local to ping instead of a member of the _dom_binding
struct. This fixes another potential ypset problem: using ypset to
force a binding to a machine that has an NIS server but which *doesn't*
support the domain we're after can result in permanently bogus bindings.
- the 'server OK' message prints the wrong IP address.
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