[openbeosnetteam] Re: CVS: net_kit/source/driver net_stack_driver.c,1.4,1.5

Philippe,

The code we had wasn't actually doing what we needed, which was why it
needed to be changed.

connect, bind and other all return -1 if they fail and set errno, so having
libnet returning the error isn't correct. However, if we return the error
from the ioctl value we get -1 as the ioctl return (so it can just be passed
back) and errno is set correctly with the appropriate value.

As for thread safeness, ISTR that errno is threadsafe...

david

----- Original Message -----
From: "Philippe Houdoin" <philippe.houdoin@xxxxxxx>
To: <openbeosnetteam@xxxxxxxxxxxxx>
Sent: Tuesday, April 30, 2002 7:33 AM
Subject: [openbeosnetteam] Re: CVS: net_kit/source/driver
net_stack_driver.c,1.4,1.5


> > Modified Files:
> > net_stack_driver.c
> > Log Message:
> > Fix some style lines...
> >
> > connect should return -1 in a failure case with the exact error being
> > available via errno, which is what this change does. I'm guessing the
> same
> > is true for a number of other functions, and ISTR that it used to be
> like this,
> > so why did we change it?
>
> In the net_stack_control() hook, the function eturn values are B_OK or
> B_ERROR because
> it's the way the ioctl() syscall expect them (and interpret them).
> These return values says: this ioctl(opcode) WAS or WAS NOT handled.
> And don't forget a ioctl(fd, opcode) could fail too, for many
> reasons (bad fd, closed fd, internal vfs problem, internal devfs
> failure,
> you name it...)
>
> It's why we need all these 'rv' in the *_args structs we use between
> libnet.so and
> net_stack_driver.c, and why in libnet.so we both check the ioctl() call
> result and,
> if the opcode was really handled (ioctl returns B_OK), then use the
> corresponding *_args struct return value, stored in the 'rv' field:
>
>   args.rv = B_ERROR;
>   rv = ioctl(sock, NET_STACK_CONNECT, &args, sizeof(args));
>   return (rv < 0) ? rv : args.rv;
>
> On this same topic, I'm not sure that from kernelland the errno is
> thread-safe. Need to
> be checked...
>
> -Philippe.
>
>
>
>
> --
> Fortune Cookie Says:
>
> Although the moon is smaller than the earth, it is farther away.
>
>
>

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