Hi Alejandro,
Thanks for replying.
The client, after connecting, processes the argv items and sends all
of them, then issues the sending of a final END which, on the server
side, is not expected after DOWN which would halt the reading (In that
case, too, the processing of argv + the END should happen).
After the change, DOWN does not break the reading, the closing END is
processed and there is no broken connection when client tries to send
END while the server closes after sending the result, which is not
received by the client.
--- without DOWN ----
client server
argv1..N + END --->
<----- result
<---- connection closed
-----------problem-----------
argv1...N + DOWN ->
<---- result
END -> ?????
<---- connection closed
------- solution:---------
argv1...N + DOWN + END ->
<---- result
<---- connection closed
I hope I did not overlook something.
OK, maybe with a unique message containing only the DOWN from client,
the issue is not visible, because there is no result to return to
client and we don't care it the connection is just broken....
Cheers
PuLi
Alejandro Colomar <alx@xxxxxxxxxx> ezt írta (időpont: 2024. márc. 4., H, 17:22):
>
> Hi Lili,
>
> > Subject: Re: patch - fixing sample program in unix.7
>
> On Sun, Mar 03, 2024 at 08:27:17PM +0100, Lili Püspök wrote:
> > diff --git a/man7/unix.7 b/man7/unix.7
>
> Please add some commit message. I don't understand what this patch
> does. How is it broken, and how does it fix it?
>
> > index cb1dcae45..7fb41af99 100644
> > --- a/man7/unix.7
> > +++ b/man7/unix.7
> > @@ -1057,7 +1057,7 @@ main(int argc, char *argv[])
> > \&
> > if (!strncmp(buffer, "DOWN", sizeof(buffer))) {
> > down_flag = 1;
> > - break;
> > + continue;
>
> DOWN is used to stop the server. How would 'continue' help?
>
>
> $ MANWIDTH=66 man unix | grep -C2 DOWN
> tegers. The client prints the sum and exits. The server
> waits for the next client to connect. To stop the server,
> the client is called with the command‐line argument "DOWN".
>
> The following output was recorded while running the server
> in the background and repeatedly executing the client. Ex‐
> ecution of the server program ends when it receives the
> "DOWN" command.
>
> Example output
> --
> $ ./client 11 -5
> Result = 6
> $ ./client DOWN
> Result = 0
> [1]+ Done ./server
> --
> /* Handle commands. */
>
> if (!strncmp(buffer, "DOWN", sizeof(buffer))) {
> down_flag = 1;
> break;
> --
> close(data_socket);
>
> /* Quit on DOWN command. */
>
> if (down_flag) {
>
> Have a lovely day,
> Alex
>
>
> > }
> > \&
> > if (!strncmp(buffer, "END", sizeof(buffer))) {
> >
>
> --
> <https://www.alejandro-colomar.es/>
> Looking for a remote C programming job at the moment.
