pthread - fork - execv problem

Daniel Eischen eischen at
Tue Jun 22 20:19:11 GMT 2004

On Tue, 22 Jun 2004, Dan Nelson wrote:

> In the last episode (Jun 22), Nikos Ntarmos said:
> > On Tue, Jun 22, 2004 at 09:56:33AM -0500, Dan Nelson wrote:
> > > It may be an application bug.  After a fork both processes are
> > > independant.  The child should not be able to affect the parent
> > > like this, unless the parent does something like holding a mutex
> > > used by all the threads and calling wait().
> > 
> > ... or the child holding a mutex before the fork(2) syscall. FWIW the
> > Linux info for libc and the NetBSD and Solaris man pages mention
> > pthread_atfork(3), used to install handlers to take care of such
> > cases. FreeBSD seems to not know of any such function, so chances are
> > that fork()'ing from inside a posix thread is not supported (?).
> It's definitely a possibility.
> libpthread in -current does support pthread_atfork, and I have a patch
> (below) that adds the same functionality to libc_r and libthr that I
> need to send-pr.  Pointy hat to the original committer for breaking ABI
> compatibility.

Whaa?  Adding a function doesn't break ABI, and I don't want
to maintain 3 thread libraries.

Dan Eischen

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