I believe threadnotify() should be called from threadmain() to
properly register the handler in the rendez group.
On Fri, Jun 17, 2022 at 5:39 AM <andrey100100...@gmail.com> wrote:
>
> Hi all!
>
> Strange behavior of syscall 'read' with signal 'alarm' in followed
> simple program (ip/port - not matter):
>
> -----------------------------------------------------------------------
> #include <u.h>
> #include <libc.h>
> #include <thread.h>
>
> static int
> handler_alarm(void *, char *msg)
> {
> if(strstr(msg, "alarm"))
> return 1;
>
> return 0;
> }
>
> static void
> proc_udp(void *)
> {
> char resp[512];
> char req[] = "request";
> int fd;
>
> threadnotify(handler_alarm, 1);
>
> if((fd = dial("udp!185.157.221.201!5678", nil, nil, nil)) >=
> 0){
> if(write(fd, req, strlen(req)) == strlen(req)){
> fprint(1, "start\n");
> alarm(2000);
> read(fd, resp, sizeof(resp));
> alarm(0);
> fprint(1, "end\n");
> }
> close(fd);
> }
>
> threadexits(nil);
> }
>
> int mainstacksize = 5242880;
>
> void
> threadmain(int argc, char *argv[])
> {
> for(int i = 0; i < 80; i++){
> proccreate(proc_udp, nil, 10240);
> }
>
> sleep(5000);
> threadexitsall(nil);
> }
> -----------------------------------------------------------------------
>
> cpu% 6.out | grep end | wc -l
> 33
>
> sometimes little more or less
> but
>
> cpu% 6.out | grep start | wc -l
> 80
>
> always.
>
> Testing on Miller's RPi and 9front (amd64 & RPi 2)
>
> Why does read() kill process?
> Why not always?
> Why number of 'ended' processes arond 33?
> This is normal behavior?
> How to fix the program so that the processes do not lost?
>
> Can someone point me in the right direction?
>
> Thanks!
> Andrey
------------------------------------------
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