Silent failure of busybox mount for unknown fs type

[Denys Vlasenko]

On Saturday 10 October 2009 21:51, Vladimir Dronnikov wrote:
> >> >
> >> > I added bb_perror_msg("can't execute '%s'", argv[0])
> >> > in spawn() in git...
> >>
> >> Hmm. spawn() was meant to be silent.
> >
> > Set logmode = 0 and it will be.
> >
> 
> What is impact in other applets then? I never knew of "logmode" at
> all. Where is it? What is it? Anyone knows of it?

I meant: if you need to call spawn() so that it does not complain,
set logmode global variable to 0 before the call.

> >> It is mount.c that should bark
> >> unless quiet option is given, IMHO.
> >
> > It is hard to reliably detect exec failure after fork.
> > Parent can only see they child exited with some exitcode or signal,
> > how it can know that child exited because exec in the child failed?
> >
> 
> Right. But then the routinr deserves to be named WARN_UNLESS_spawn(),
> doesn't it?

> And, personally, spent time to make ntfs-3g mount helper 
> silent (patch can be given) if it is a helper to mount NTFS. Otherwise
> it constantly barks when I try ti auto-mount non-NTFS devices which
> happen to have filesystem named farther than ntfs (squashfs, e.g.) --
> that is because the kenrel tries to auto=probe filesystems by the
> order
> thay go in /{etc,proc}/filesystems (really, kernel-side Kbuild(s)). Do
> we mean it?

Aha, I see. There is a case when mount tries many filesystems,
and complaining "can't run mount.<fs1>", "can't run mount.<fs2>"
is bad.

It would be much easier to understand the problem if you would simply
show the command where it is a problem. Like this:

# busybox mount /dir/in/fstab
mount: can't execute 'mount.reiserfs': No such file or directory
mount: can't execute 'mount.ext3': No such file or directory
mount: can't execute 'mount.ext2': No such file or directory
mount: can't execute 'mount.cramfs': No such file or directory
mount: can't execute 'mount.minix': No such file or directory
mount: can't execute 'mount.vfat': No such file or directory
mount: can't execute 'mount.msdos': No such file or directory
mount: can't execute 'mount.iso9660': No such file or directory
mount: can't execute 'mount.romfs': No such file or directory
mount: mounting /dev/hdb on /dir/in/fstab failed: Input/output error

Ok. I am reverting the change to spawn().
--
vda