Re: [lwip-users] threading issues with sockets

[Simon Goldschmidt]

"Åke Forslund" <address@hidden> wrote:
> I'm not quite sure how to handle the situation since when using blocking
> sockets lwip_read() doesn't return even if the link goes down (? is this
> expected behavior?)

A link-down event shouldn't cause read() to abort, I guess, since you could 
re-plug the device into the same network again.

A netif-down event (which is what stopping DHCP does) however should cause the 
read() to abort since the IP address is gone.

> so I can't use a semaphore to ensure that socket functions
> can't be accessed at the same time as the netifapi_*()-functions.
> 
> Any advice on how to handle link-status changes together with sockets in a
> safe manner would be great.

I'm not aware of problems here. As far as I know, there should be no problems 
with what you described. As you are having problems, I don't have any 
suggestions except for debugging to see which threads are pending on which 
semaphores, I'm afraid. A stack trace of all threads at the time of suspected 
deadlock would be helpful to give more hints.

Simon
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