This is the mail archive of the mailing list for the glibc project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: extending wait4(2) or waitid(2) linux syscall

* Arnd Bergmann:

> On Thu, Nov 15, 2018 at 7:30 AM Dmitry V. Levin <> wrote:
>> On Thu, Nov 15, 2018 at 06:39:03AM -0800, Arnd Bergmann wrote:
>> > On Thu, Nov 15, 2018 at 6:05 AM Dmitry V. Levin wrote:
>> > > On Thu, Apr 20, 2017 at 03:20:51PM +0200, Albert ARIBAUD wrote:
>> 1. strace needs a race-free invocation of wait4(2) or waitid(2)
>> with a different signal mask, this cannot be achieved without
>> an extended version of syscall, similar to pselect6(2) extension
>> over select(2) and ppoll(2) extension over poll(2).
>> Signal mask specification in linux requires two parameters:
>> "const sigset_t *sigmask" and "size_t sigsetsize".
>> Creating pwait6(2) as an extension of wait4(2) with two arguments
>> is straightforward.
>> Creating pwaitid(2) as an extension of waitid(2) that already has 5
>> arguments would require an indirection similar to pselect6(2).
> Getting back to this point: you could also do the same thing with
> the CLONE_FD approach from Josh Triplett[1] or Casey Dahlin's
> older waitfd() syscall, correct?

A descriptor-based solution would not be useful to glibc because
applications assume that glibc does not (persistently) open any file
descriptors behind t heir back.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]