Re: select() on sockets considered harmful, use poll() instead?

[Juan Lang]

Dan wrote:
> The suspect statements are:
>
> dinput/joystick_linux.c:      if (1>select(This->joyfd+1,&readfds,...
> dinput/joystick_linuxinput.c: if (1>select(This->joyfd+1,&readfds,...
> icmp/icmp_main.c:             while ((res=select(icp->sid+1,&fdr,...
> netapi32/nbt.c:               r = select(fd + 1, &fds, ...
> wininet/internet.c:           if (select(nSocket+1,&infd,...
> wininet/netconnection.c:      if
> (select(connection->socketFD+1,&infd,...

These, at least, are safe:  they poll on a single file descriptor.
> ws2_32/socket.c:              if( (highfd = select(highfd + 1, p_read,
> p_write, p_except, timeoutaddr))

This is the only potentially problematic one, but I didn't look at it
closely enough to know for sure.
--Juan


 
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select() on sockets considered harmful, use poll() instead?

[Alexandre Julliard]

Juan Lang <juan_lang(a)yahoo.com> writes:
> Dan wrote:
> > The suspect statements are:
> >
> > dinput/joystick_linux.c:      if (1>select(This->joyfd+1,&readfds,...
> > dinput/joystick_linuxinput.c: if (1>select(This->joyfd+1,&readfds,...
> > icmp/icmp_main.c:             while ((res=select(icp->sid+1,&fdr,...
> > netapi32/nbt.c:               r = select(fd + 1, &fds, ...
> > wininet/internet.c:           if (select(nSocket+1,&infd,...
> > wininet/netconnection.c:      if
> > (select(connection->socketFD+1,&infd,...
>
> These, at least, are safe:  they poll on a single file descriptor.

A single file descriptor can still be above 1024. select() should
really be avoided.

-- 
Alexandre Julliard
julliard(a)winehq.org

select() on sockets considered harmful, use poll() instead?

[Damjan Jovanovic]

On 11/1/06, Alexandre Julliard <julliard(a)winehq.org> wrote:
> Juan Lang <juan_lang(a)yahoo.com> writes:
> > Dan wrote:
> > > The suspect statements are:
> > >
> > > dinput/joystick_linux.c:      if (1>select(This->joyfd+1,&readfds,...
> > > dinput/joystick_linuxinput.c: if (1>select(This->joyfd+1,&readfds,...
> > > icmp/icmp_main.c:             while ((res=select(icp->sid+1,&fdr,...
> > > netapi32/nbt.c:               r = select(fd + 1, &fds, ...
> > > wininet/internet.c:           if (select(nSocket+1,&infd,...
> > > wininet/netconnection.c:      if
> > > (select(connection->socketFD+1,&infd,...
> >
> > These, at least, are safe:  they poll on a single file descriptor.
>
> A single file descriptor can still be above 1024. select() should
> really be avoided.

Well I'm not a new wine hacker, but I was bored this weekend, so:
> dinput/joystick_linux.c:      if (1>select(This->joyfd+1,&readfds,...
> patch sent
> dinput/joystick_linuxinput.c: if (1>select(This->joyfd+1,&readfds,...
> patch sent
> icmp/icmp_main.c:             while ((res=select(icp->sid+1,&fdr,...
> patch sent
> netapi32/nbt.c:               r = select(fd + 1, &fds, ...
> This is a winsock select, which is okay: the winsock fd_set is just an
> array, meaning the single fd can be > 1024. Alexandre's WS_select patch
> makes WS_select use poll internally, so this will always work. Besides,
> there's no real alternative to select in winsock ;-).

So changing select->poll only needs to be done for the Linux select.
> wininet/internet.c:           if (select(nSocket+1,&infd,...
> patch sent
> wininet/netconnection.c:      if (select(connection->socketFD+1,&infd,...
> patch sent
> ws2_32/socket.c:              if( (highfd = select(highfd + 1, p_read,
> p_write, p_except, timeoutaddr))
> Alexandre's WS_select patch fixes this

cscope did not find any more select() calls in wine 0.9.24 dlls, except
a few used for timing and yielding execution. Should we change those too
for consistency?

Damjan