From: "Petr Skočík" <pskocik@gmail.com>
To: cygwin@cygwin.com
Subject: uc_sigmask set in a sigaction signal handler not honored
Date: Wed, 03 Apr 2019 09:28:00 -0000 [thread overview]
Message-ID: <366918d8-b505-45be-dc28-303579f17341@gmail.com> (raw)
Hi. Correct me if I'm wrong but POSIX appears to define
https://pubs.opengroup.org/onlinepubs/7908799/xsh/ucontext.h.html
as, among other things, containing the field:
sigset_t uc_sigmask the set of signals that are blocked when this
context is active
and it also specifies that the third argument to a .sa_sigaction
signal handler is a ucontext_t* cast to void*.
So it should follow that doing
void act(int Sig, siginfo_t *Info, void *Uctx)
{
ucontext_t *uctx = Uctx;
sigfillset(&uctx->uc_sigmask);
}
from a signal handler should alter the signal mask of the thread the
signal ran on.
This is how Linux and MacOS behave, but not CygWin, as the following
program shows:
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/time.h>
void prmask(void)
{
sigset_t mask; pthread_sigmask(SIG_SETMASK,0,&mask);
for(int i=1; i<=64; i++){ printf("%d", sigismember(&mask,i)); } puts("");
}
void act(int Sig, siginfo_t *Info, void *Uctx)
{
ucontext_t *uctx = Uctx;
sigfillset(&uctx->uc_sigmask);
}
int main()
{
struct sigaction sa;
sa.sa_sigaction = act;
sa.sa_flags = SA_SIGINFO;
sigfillset(&sa.sa_mask);
prmask();
sigaction(SIGINT,&sa,0);
sigaction(SIGALRM,&sa,0);
if(1)
setitimer(ITIMER_REAL,&(struct itimerval){.it_value={.tv_usec=10000}},0);
pause();
prmask();
}
I think this is a bug, so I'm reporting it. Do you think it can be fixed
in the near future?
Best regards,
Petr Skocik
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next reply other threads:[~2019-04-03 9:28 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-03 9:28 Petr Skočík [this message]
2019-04-03 12:16 ` Corinna Vinschen
2019-04-03 12:43 ` Corinna Vinschen
2019-09-09 17:13 ` malloc(0) crashes with SIGABRT Petr Skočík
2019-09-09 18:27 ` malloc(0) crashing " Petr Skočík
2019-09-12 3:59 ` Brian Inglis
2019-09-12 11:33 ` Kaz Kylheku
2019-09-12 18:05 ` Brian Inglis
2019-09-12 17:38 ` Ken Brown
[not found] ` <e20e38ff-49b1-6472-b0a4-faeee0176a7c@gmail.com>
2019-09-13 13:21 ` Ken Brown
2019-04-03 14:39 uc_sigmask set in a sigaction signal handler not honored Petr Skočík
2019-04-03 16:29 ` Corinna Vinschen
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