Re: [Libunwind-devel] [PATCH] x86_64: fix mincore_validate and msync_validate

[Dave Watson]

On 08/18/17 09:46 AM, Paul Pluzhnikov wrote:
> On Fri, Aug 18, 2017 at 8:16 AM, Dave Watson <address@hidden> wrote:
> 
> > and also handle EINTR
> 
> > +      int bytes = read (validate_pipe[0], &buf, 1);
> > +      if (bytes >= 0 || errno == EAGAIN || errno == EWOULDBLOCK)
> 
> On Linux:
> 
> #define EWOULDBLOCK EAGAIN /* Operation would block */
> 
> Did you mean errno == EINTR above?

No, EINTR should retry again in the loop.  I just went by the manpage that 
claims

EAGAIN or EWOULDBLOCK
      The file descriptor fd refers to a socket and has been marked nonblocking 
 (O_NONBLOCK),  and  the  read  would
      block.   POSIX.1-2001 allows either error to be returned for this case, 
and does not require these constants to
      have the same value, so a portable application should check for both 
possibilities.