[debbugs-tracker] bug#12494: closed (0 exit status even when chmod fails)

[GNU bug Tracking System]

Your message dated Tue, 25 Sep 2012 08:57:41 +0200
with message-id <address@hidden>
and subject line Re: bug#12494: 0 exit status even when chmod fails
has caused the debbugs.gnu.org bug report #12494,
regarding 0 exit status even when chmod fails
to be marked as done.

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-- 
12494: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=12494
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> Subject: 
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> 0 exit status even when chmod fails
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> Date: 
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> Sun, 23 Sep 2012 01:59:37 -0400
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> User-agent: 
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> Mozilla/5.0 (X11; Linux x86_64;	rv:15.0) Gecko/20120911 Thunderbird/15.0.1
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> I was helping a newbie friend of mine try to get some games of his 
> running. It quickly became apparent that the program didn't have execute 
> permission. I thought a simple chmod 755 would do the job. Apparently 
> not. We try again and check afterwards. Still won't execute. We do it 
> again. We check the exit status. Executable? No. Exit status? 0.  
> Compiled for Linux and not say Winblowse? Yes. What the bloody hell was 
> going on here?
>
> There were a few more vain tries. We tried following through on other 
> crackpot ideas of mine to no avail. Then came ripping out all the hair 
> on my head and other places best left to the imagination, waiting for it 
> to regrow and doing it all over again.
>
> Finally I had him show me the mount options of the relevant partitions. 
> Many I recognized. Some I did not. I started researching those I did 
> not. It turns out they had nothing to do with the problem at hand. But I 
> did inadvertently find out what went wrong as a consolation prize. 
> Apparently chmod doesn't work on vfat or ntfs. Ultimately it was 
> understandable as the permission schemes are radically different and now 
> that I thought about it that'd be quite a feat to be able to translate 
> between them in any meaningful way.
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> Chmod doesn't work on vfat? Fair enough. But it shouldn't be returning a 
> 0 exit code for failure. Generally when chmod fails or can't do 
> something it returns an non-zero exit code. I see no reason that there 
> should be an exception just because it's incompatible with vfat. This 
> can be very problematic in scripts that rely on knowing the success of 
> the command/exit code. Please look into this.
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> --- Begin Message ---
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> Subject: 
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> Re: bug#12494: 0 exit status even when chmod fails
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> Date: 
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> Tue, 25 Sep 2012 08:57:41 +0200
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> Sven Joachim wrote:
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> > On 2012-09-24 21:25 +0200, Alan Curry wrote:
> >
> >> If the mount man page disagrees with the kernel, it's still a bug in the man
> >> page at least.
> >
> > Possibly, but the mount manpage is not part of coreutils.
> >
> >> (Also, the rest of the world needs to work around extra stupidity because of
> >> rsync?)
> >
> > No, all stupidity here belongs to the FAT filesystems.  And the kernel
> > devs thankfully have a strict policy of not breaking userspace, so it's
> > unlikely that the behavior of chmod(2) will ever be changed; in any case
> > there's nothing coreutils can do.
>
> Thanks for explaining.  I've closed this bug.
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>
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