[openbeosnetteam] News about select() support under BeOS R5.0.3 kernel...

Okay, you guys were right about R5.0.3 and select() problem!
My code doesn't works under R5.0.3. :-( (beside the need to fix some 
compilation errors...)

Not without some tweaks :-)

Problems are:
- R5.0.3 kernel_intel have a select() call, but is not exported.
- Be Inc' libnet.so export a select() call, but this one don't works 
with file descriptors, only with R5 net_server sockets.

/me thinks this point explain the previous one: name collision, so 
someone at Be thinks as select() is mostly used with sockets, 
 it's best to overide the kernel fd select() instead of renaming the 
libnet.so call into something like socketselect(), like they did for 
closesocket()...

- lib_tester app can't link against _KERNEL_ to use the kernel select() 
call. 

Now, the good news:

- net_stack_driver, like any driver, can perfectly link against 
_KERNEL_ (in fact they have to!). So, from our driver, 
we can call the kernel select() call. It's where the tweak is:
I've added a special ioctl to *publish* real select() call to userland 
app/lib...
;-)

device_control(fd, op_code, ...)
{
        switch ( op_code ) {
        case NET_STACK_SELECT:
                {
                select_ioctl * ctl = (select_ioctl *) data;

                DEBUG_ONLY( dprintf(LOGID "--- device_control %p: select().\n", 
ep) );          
                return select(ctl->nbits, ctl->read_set, ctl->write_set, ctl->
exception_set, ctl->timeout);
                };
..              
}

- In lib/socket.c I add a net_select() call, which in turn open the /
dev/net/stack driver to do the real call:

int net_select(int nbits, struct fd_set *rbits, struct fd_set *wbits, 
struct fd_set *ebits, struct timeval *timeout)
{
        int                             tmp_sock;
        select_ioctl    ctl;
        int                             rc;

        tmp_sock = open(g_stack_driver_path, O_RDWR);
        if (tmp_sock < 0)
                return tmp_sock;
        
        ctl.nbits                       = nbits;
        ctl.read_set            = rbits;
        ctl.write_set           = wbits;
        ctl.exception_set               = ebits;
        ctl.timeout                     = timeout;
        
        rc = ioctl(tmp_sock, NET_STACK_SELECT, &ctl);
        close(tmp_sock);
        return rc;
}

I don't try to name it select(), but I guess it should works too...

- notify_select_event() perfectly works under R5.0.3 kernel :-)
For read, write and exception events. Remember, the R5 libnet.so' 
select() only works for sockets and only for ready to read event!...

Here the result:

$ lib_tester
socket(AF_INET, SOCK_STREAM, 0) -> 3
connect(3, INADDR_LOOPBACK, 21) failed!
select_test_thread: triggering 2 select event...
socket 3 ready to write.

Messages send into /var/log/syslog by the driver:
KERN 'lib_tester'[3820]: net_stack: --- init_driver, built Mar  1 2002 
01:02:29
KERN 'lib_tester'[3820]: net_stack: load_driver_symbols("net_stack") 
done.
KERN 'lib_tester'[3820]: net_stack: --- find_device net/stack
KERN 'lib_tester'[3820]: net_stack: --- device_open net/stack (O_RDWR) 
-> 0x01731200
KERN 'lib_tester'[3820]: net_stack: --- device_control 0x01731200: 
socket(1, 2, 0).
KERN 'lib_tester'[3820]: net_stack: --- device_control 0x01731200: 
connect().
KERN 'lib_tester'[3820]: net_stack: --- device_open net/stack (O_RDWR) 
-> 0x00de91d0  
KERN 'lib_tester'[3820]: net_stack: --- device_control 0x00de91d0: 
select(). 
KERN 'lib_tester'[3820]: net_stack: --- device_select 0x01731200: 1, 
16777219, 0x0177b244
KERN 'lib_tester'[3820]: net_stack: --- device_select 0x01731200: 2, 
33554435, 0x0177b244
KERN 'lib_tester'[3820]: net_stack: --- device_select 0x01731200: 3, 
50331651, 0x0177b244
KERN 'lib_tester'[3820]: net_stack: --- device_deselect 0x01731200: 1, 
0x0177b244
KERN 'lib_tester'[3820]: net_stack: --- device_deselect 0x01731200: 2, 
0x0177b244
KERN 'lib_tester'[3820]: net_stack: --- device_deselect 0x01731200: 3, 
0x0177b244
KERN 'lib_tester'[3820]: net_stack: --- device_close 0x00de91d0
KERN 'lib_tester'[3820]: net_stack: --- device_free 0x00de91d0
KERN 'lib_tester'[3820]: net_stack: --- device_close 0x01731200
KERN 'lib_tester'[3820]: net_stack: --- device_free 0x01731200
KERN 'lib_tester'[3820]: net_stack: --- uninit_driver       

R5 kernel have full select() support, but it's not exported to userland 
apps only because of name collision with net_server sockets dedicated 
select() call, exported by R5 libnet.so...
It would be very easy to make a small driver + library only to add real 
file descriptor select() support to R5.0.x...

Could be easier, but anyway it *works* !!!

Time to have some sleep...

-Philippe.

 

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