Link of ONC RPC client fails with: undefined references

Link of ONC RPC client fails with: undefined references

[Voris, Ben]

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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"

Making RPC header file rpcgen_output/date.h from date.x
mkdir -p rpcgen_output/
rm -f rpcgen_output/date.h
rpcgen -h -o rpcgen_output/date.h date.x
Compiling objs/date_client.o from src/date_client.c
mkdir -p objs/
gcc -c -g -O0 -I ./rpcgen_output/ -oobjs/date_client.o src/date_client.c
Making RPC client stub rpcgen_output/date_clnt.c from date.x
mkdir -p rpcgen_output/
rm -f rpcgen_output/date_clnt.c
rpcgen -l -o rpcgen_output/date_clnt.c date.x
Compiling objs/date_clnt.o from rpcgen_output/date_clnt.c
mkdir -p objs/
gcc -c -g -O0 -I ./rpcgen_output/ -oobjs/date_clnt.o rpcgen_output/date_clnt.c
Making objs/date_client from objs/date_client.o objs/date_clnt.o
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_wrapstring]+0x0): undefined reference to `xdr_wrapstring'
collect2: error: ld returned 1 exit status
make: *** [Makefile:53: objs/date_client] Error 1

Building the server also fails but with different errors. Output of "make objs/date_server":

Compiling objs/date_server.o from src/date_server.c
mkdir -p objs/
gcc -c -g -O0 -I ./rpcgen_output/ -oobjs/date_server.o src/date_server.c
src/date_server.c: In function 'get_remote_date_1_svc':
src/date_server.c:34:30: warning: initialization of 'struct sockaddr_in *' from incompatible pointer type 'struct sockaddr_in6 *' [-Wincompatible-pointer-types]
   34 |   struct sockaddr_in *sock = svc_getcaller(
      |                              ^~~~~~~~~~~~~
Making RPC server code rpcgen_output/date_svc.c from date.x
mkdir -p rpcgen_output/
rm -f rpcgen_output/date_svc.c
rpcgen -s tcp -o rpcgen_output/date_svc.c date.x
Compiling objs/date_svc.o from rpcgen_output/date_svc.c
mkdir -p objs/
gcc -c -g -O0 -I ./rpcgen_output/ -oobjs/date_svc.o rpcgen_output/date_svc.c
Making objs/date_server from objs/date_server.o objs/date_svc.o
gcc -ltirpc -o objs/date_server objs/date_server.o objs/date_svc.o
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: objs/date_svc.o: in function `date_prog_1':
/home/BVoris/git/ONC-rpc-test/rpcgen_output/date_svc.c:31: undefined reference to `svc_sendreply'
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: /home/BVoris/git/ONC-rpc-test/rpcgen_output/date_svc.c:41: undefined reference to `svcerr_noproc'
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: /home/BVoris/git/ONC-rpc-test/rpcgen_output/date_svc.c:46: undefined reference to `svcerr_decode'
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: /home/BVoris/git/ONC-rpc-test/rpcgen_output/date_svc.c:50: undefined reference to `svc_sendreply'
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: /home/BVoris/git/ONC-rpc-test/rpcgen_output/date_svc.c:51: undefined reference to `svcerr_systemerr'
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: objs/date_svc.o: in function `main':
/home/BVoris/git/ONC-rpc-test/rpcgen_output/date_svc.c:65: undefined reference to `pmap_unset'
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: /home/BVoris/git/ONC-rpc-test/rpcgen_output/date_svc.c:67: undefined reference to `svctcp_create'
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: /home/BVoris/git/ONC-rpc-test/rpcgen_output/date_svc.c:72: undefined reference to `svc_register'
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: /home/BVoris/git/ONC-rpc-test/rpcgen_output/date_svc.c:77: undefined reference to `svc_run'
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: objs/date_svc.o:date_svc.c:(.rdata$.refptr.xdr_wrapstring[.refptr.xdr_wrapstring]+0x0): undefined reference to `xdr_wrapstring'
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: objs/date_svc.o:date_svc.c:(.rdata$.refptr.xdr_void[.refptr.xdr_void]+0x0): undefined reference to `xdr_void'
collect2: error: ld returned 1 exit status
make: *** [Makefile:61: objs/date_server] Error 1


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Re: Link of ONC RPC client fails with: undefined references

[Jon Turney]

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_wrapstring]+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 https://cygwin.com/faq.html#faq.programming.linker for details why.

RE: 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.