Re: RPC clnt_create() adress already in use

[Mark Geisert <mark@maxrnd.com>]

Hello Raimund,
Let's keep this on the mailing list please.

PAULUS, Raimund, TI-ABN wrote:
> Hallo Mark Geisert,
>
> many thanks for your answer. I supposed this too.
>
> I included in my source code the following function calls after clnt_create():
>
> int fd = 0;
> bool bool_ret = clnt_control(cl, CLGET_FD, &fd); if(bool_ret == true) {
>   printf("fd: %d\n", fd);
>
>   int enable = 1;
>   retval = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int));
>   if(retval < 0)
>     fprintf(stderr, "Fehler setsockopt(): %s\n", strerror(errno)); }
>
> The function clnt_control() delivers the socket of the RPC-Client-Handle.
> The result is the same as before. Moreover i think, the effect of setsockopt() would be valid only during the process is running (my test scenarios 1 and 2).
> But it wouldn't change anything regarding my test scenario 3 (several restarts).
>
> Raimund

I looked through the libtirpc source code and nowhere is SO_REUSEADDR being set. 
  You are on the right track with how to do it, but by the time clnt_create() 
returns to you it is already too late.  As far as I can tell there is no way to 
get access to the socket between the time it's created within libtirpc and the 
time it's made available to you by clnt_create().

I did try running your testcase (thanks for supplying that) but I don't have a 
local machine running RPC services and don't wish to poke at random machines on 
the Internet ;-).  I had to compile it as so:
     gcc -g -o test_rpc -I/usr/include/tirpc test_rpc.c -ltirpc
You are taking care to compile against the correct RPC-package includes and link 
against the correct RPC-package libraries, yes?

Speculation: There might be a way to decompose what clnt_create() does into 
other libtirpc functions that accomplish the same thing, but in smaller pieces 
such that you could set the socket option before bind() is called.  That would 
be a fair amount of work though and given my cursory look at the source I don't 
know if it's even possible.

..mark

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