From: Rich Felker <dalias@aerifal.cx>
To: Yousong Zhou <yszhou4tech@gmail.com>
Cc: Pedro Alves <palves@redhat.com>,
gdb-patches@sourceware.org, musl@lists.openwall.com
Subject: Re: [musl] Re: [PATCH] Fix invalid sigprocmask call
Date: Fri, 24 Mar 2017 11:35:30 -0400 [thread overview]
Message-ID: <20170324153530.GF17319@brightrain.aerifal.cx> (raw)
In-Reply-To: <CAECwjAhpQMfz3vRWX=VFfJTBt+=950_fJnEj6H-6h05Vk85zjg@mail.gmail.com>
On Fri, Mar 24, 2017 at 09:05:15PM +0800, Yousong Zhou wrote:
> On 24 March 2017 at 20:55, Pedro Alves <palves@redhat.com> wrote:
> > On 03/24/2017 12:23 PM, Yousong Zhou wrote:
> >> On 24 March 2017 at 18:47, Pedro Alves <palves@redhat.com> wrote:
> >>> On 03/24/2017 03:01 AM, Yousong Zhou wrote:
> >>>> The POSIX document says
> >>>>
> >>>> The pthread_sigmask() and sigprocmask() functions shall fail if:
> >>>>
> >>>> [EINVAL]
> >>>> The value of the how argument is not equal to one of the defined values.
> >>>>
> >>>> and this is how musl-libc is currently doing. Fix the call to be safe
> >>>> and correct
> >>>>
> >>>> [1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_sigmask.html
> >>>>
> >>>
> >>> I don't agree. It's a musl bug. Please fix it / file a musl bug.
> >>
> >> I already did that before sending to gdb-patches
> >>
> >> http://www.openwall.com/lists/musl/2017/03/24/1
> >>
> >> I am aware of the fact that the current code works with glibc and mac
> >> osx 10.11.6. The Linux kernel code at the moment also accepts the
> >> call with how==0
> >
> > Cool.
> >
> >>
> >> But this is more about interpretation of POSIX document itself. And
> >> it says, clearly without pre-condition words or ambiguity in the
> >> ERRORS section of that page, to return EINVAL if how is not equal to
> >> one of the defined values.
> >
> > The standard wasn't built on a vacuum. It starts by ratifying common
> > implementation behavior. If no historical implementation behaves like what
> > you're suggesting, what's the point of enforcing that, when it's clearly
> > NOT the intent? You're just causing porting pain for no good reason.
> > Please file a bug against the standard to have the error section clarified instead.
>
> Lol, now I will consider the idea of bumping the door of POSIX committee ;)
If you file a report and it's deemed a bug in the standard and
changed, I'm happy to change this on the musl side. Just keep me
posted on what happens. I don't have any preference on what the
behavior "should" be here (IMO imposing a behavior when the caller has
violated constraints like passed a wrong value for how is pointless
anyway) but I do want to conform to the standard.
> >> I also tried to find some posix-compliant testsuite and to search the
> >> github code for samples of pthread_sigmask call. The first I came
> >> across was the following code snippet at link
> >> https://github.com/juj/posixtestsuite/blob/master/conformance/interfaces/pthread_sigmask/8-1.c#L57
> >>
> >> pthread_sigmask(SIG_BLOCK, NULL, &oactl);
> >
> > The fact that that call includes SIG_BLOCK doesn't say whether
> > passing 0 should be rejected.
> >
> > So I cloned that repo, and did a quick grep. And lo:
> >
> > https://github.com/juj/posixtestsuite/blob/26372421f53aeeeeeb4b23561c417886f1930ef6/conformance/interfaces/fork/12-1.c#L187
> >
> > /* Examine the current blocked signal set. USR1 & USR2 shall be present */
> > ret = sigprocmask( 0, NULL, &mask );
> >
> > if ( ret != 0 )
> > {
> > UNRESOLVED( errno, "Sigprocmask failed in child" );
> > }
> >
> > Thanks,
> > Pedro Alves
> >
>
> Okay, then another fact that the posixtestsuite project also expects
> to accept how==0
>
> I am cc-ing musl-libc list now.
If you're talking about "Open POSIX Test Suite", which the above link
seems to point to a fork of, the majority of its tests are invalid,
invoking undefined behavior then asserting that the error/effect they
wrongly expect happens. Without a thorough audit of its test validity
it's less than worthless.
Rich
next prev parent reply other threads:[~2017-03-24 15:35 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1490324519-11228-1-git-send-email-yszhou4tech@gmail.com>
[not found] ` <2b0bab84-e36e-e109-5444-dc84369dddce@redhat.com>
[not found] ` <CAECwjAgARveAhY=8e8J6Bcv+5=W=YnGcLY9G9Dv1sEnkNePVZA@mail.gmail.com>
[not found] ` <39f28782-65e8-0f52-3c8f-134a6f05788b@redhat.com>
2017-03-24 13:05 ` Yousong Zhou
2017-03-24 13:37 ` Pedro Alves
2017-03-25 0:35 ` Yousong Zhou
2017-03-24 15:35 ` Rich Felker [this message]
2017-03-24 15:52 ` [musl] " Pedro Alves
2017-03-24 16:41 ` Rich Felker
2017-03-24 17:33 ` Andreas Schwab
2017-03-24 18:14 ` Rich Felker
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