Re: [9fans] syscall silently kill processes

[andrey100100100@gmail.com]

В Вс, 19/06/2022 в 10:32 +0000, adr пишет:
> On Sun, 19 Jun 2022, andrey100100100@gmail.com wrote:
> > No way. All processes must run simultaneously.
> > NFN limit cannot be bypassed.
> 
> Yeah, that's why I said it was silly:
> > > > The solution is obvious, cancel the process' handlers before it
> > > > exits so we don't run out of space.
> > > 
> > > This was really silly...
> 
> The changes I'm testing are not for evading the limit, but for
> making the handler managment more efficient and specially to avoid
> the case when a process could remove another process' handler from
> onnote[].

Ok.


More complete example with thread library:

-------------------------------------------------------------
#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_func(void *c)
{
        Channel *chan = c;

        int fd, resp_len;
        char req[] = "request";
        char resp[512], *r = nil;

        if(threadnotify(handler_alarm, 1) == 0){
                fprint(1, "handler not registred\n");
        }

        alarm(2000);
        if((fd = dial("udp!185.157.221.201!5678", nil, nil, nil)) >=
0){
                alarm(0);
                alarm(2000);
                if(write(fd, req, strlen(req)) == strlen(req)){
                        alarm(0);
                        alarm(2000);
                        if((resp_len = read(fd, resp, sizeof(resp))) >
0){
                                alarm(0);
                                if((r = malloc(sizeof(resp))) == nil){
                                        sysfatal("malloc error: %r");
                                }
                                memmove(r, resp, sizeof(resp));
                        }
                }
                close(fd);
        }

        send(chan, r);
        threadexits(nil);
}

int mainstacksize = 5242880;

void
threadmain(int argc, char *argv[])
{
        Channel *chan = nil;
        char *data = nil;
        int nproc = 0;

        ARGBEGIN{
        case 'n':
                nproc = atoi(EARGF(threadexitsall(nil)));
                break;
        default:
                threadexitsall(nil);
        }ARGEND;

        if((chan = chancreate(sizeof(char *), 0)) == nil){
                sysfatal("channel error: %r");
        }

        for(int i = 0; i < nproc; i++){
                proccreate(proc_func, chan, 10240);
        }

        for(int i = 0; i < nproc; i++){
                if(data = recvp(chan)){
                        free(data);
                }
        }

        if(nproc)
                fprint(1, "EXIT with nproc: %d\n", nproc);

        threadexitsall(nil);
}
-------------------------------------------------------------

cpu% 6.out -n 33
EXIT with nproc: 33

with 34:

cpu% 6.out -n 34
handler not registred

and stalled.


So it is important for me that all processes respond.
Such use, it seems to me, simplifies the program.


Regards,
Andrej



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