Link of ONC RPC client fails with: undefined references

[Voris, Ben]

Thank you.

This fixed it:

-       $(CC) $^ $(LD_LIBS) -o $@
+       $(CC) $(LD_LIBS) -o $@ $^

Now I'm trying to understand why rpcbind fails at /usr/src/debug/rpcbind-1.2.5-1/src/rpcbind.c:287, even when run from an elevated command prompt:

268         if((p = getpwnam(id)) == NULL) {
269             syslog(LOG_ERR, "cannot get uid of '%s': %m", id);
270             exit(1);
271         }
...
285                     if (setuid(p->pw_uid) == -1) {
286                             syslog(LOG_ERR, "setuid to '%s' (%d) failed: %m", id, p->pw_uid);
287                             exit(1);
288                     }

I do find this:

Under "Switching the user context", https://cygwin.com/cygwin-ug-net/ntsec.html says

> Windows does not support the concept of these calls in a simple fashion.
> Switching the user context in Windows is generally a tricky process with lots
> of "behind the scenes" magic involved.
>
> \[H\]ow can this \[information\] be used to implement set(e)uid? Well, it
> requires modification of the calling application.

Based on skim of the this source, that implies that this rpcbind would never work which doesn't make sense.


> -----Original Message-----
> From: Jon Turney <jon.turney@dronecode.org.uk>
> Sent: 29 April 2022 05:29
> To: Voris, Ben <ben.voris@hpe.com>; The Cygwin Mailing List <cygwin@cygwin.com>
> Subject: Re: Link of ONC RPC client fails with: undefined references
> 
> On 29/04/2022 04:06, Voris, Ben wrote:
> > I have simple ONC RPC client and server that build on Ubuntu with rpcgen
> "(Ubuntu GLIBC 2.31-0ubuntu9.7) 2.31" (under "5.10.102.1-microsoft-standard-
> WSL2") but fails to build on Cygwin ("3.3.4(0.341/5/3) 2022-01-31 19:35 x86_64
> Cygwin") with rpcgen "(rpcsvc-proto) 1.4".
> >
> > Naively, it appears that Ubuntu has a much newer version (2.31) than Cygwin
> (1.4). Is this the problem?
> >
> > gzip'ed cygcheck output and the test program and makefile are attached.
> >
> > Output of "make all"
> [...]
> > gcc -ltirpc -o objs/date_client objs/date_client.o objs/date_clnt.o
> > /usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld:
> objs/date_client.o: in function `date_prog_1':
> > /home/BVoris/git/ONC-rpc-test/src/date_client.c:15: undefined reference to
> `clnt_create'
> > /usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld:
> /home/BVoris/git/ONC-rpc-test/src/date_client.c:17: undefined reference to
> `clnt_pcreateerror'
> > /usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld:
> /home/BVoris/git/ONC-rpc-test/src/date_client.c:33: undefined reference to
> `clnt_perror'
> > /usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld:
> objs/date_clnt.o:date_clnt.c:(.rdata$.refptr.xdr_wrapstring[.refptr.xdr_wrapstr
> ing]+0x0): undefined reference to `xdr_wrapstring'
> 
> I suspect the problem here is due to the position of '-ltirpc' in the
> compiler command line. Moving it to after the .o files might help.
> See
> INVALID URI REMOVED
> _;Iw!!NpxR!mh4II02xebe-
> AOaVrVnhqLMZ184wpNJtizkEmBv2uzw49eZ11dNZZClae3F00QGiI4IjKo7KYcBeP0qGGZVCzgU$
> for details why.