Re: nfs-utils broken with musl: "select: Bad file descriptor"

[Rich Felker <dalias@libc.org>]

On Tue, Aug 18, 2015 at 04:30:21AM +0200, Tastky wrote:
> As by this OpenWRT bugreport:
> https://dev.openwrt.org/ticket/20038
> 
> On various architectures – at least a mips and powerpc one –
> nfs-utils is broken with musl, yielding a never ending stream of
> "my_svc_run() - select: Bad file descriptor" in the system log.
> 
> The message originates in the this file:
> http://git.linux-nfs.org/?p=steved/nfs-utils.git;a=blob;f=utils/statd/svc_run.c
> 
> "Downgrading" to uClibc has the issue vanish.
> 
> I verified this myself with recent git versions of both musl and the
> utils on a fresh ar71xx OpenWRT compilation.

Here's my quick guess at what's going wrong. This file:

http://git.linux-nfs.org/?p=steved/nfs-utils.git;a=blob;f=utils/statd/system.h;h=a1739c491474179c16a64f7a2bbfde8f651085c6;hb=HEAD

contains nonsense to define SVC_FDSET as int rather than using fd_set
on "systems which don't have fd_set" (which don't exist).
Unfortunately, it's checking #ifdef FD_SETSIZE without including the
header that defines it, sys/select.h. If this is the problem, adding:

#include <sys/select.h>

to the top of that file should fix the error.

Note that compiling with -Werror=implicit-function-declaration would
catch such bogus code right away.

If this turns out not to be the problem, can you send an strace of the
failing program up to the first failure message?

Rich