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#include <u.h>
#include <signal.h>
#include <libc.h>
#define DBG 0
static void
ign(int x)
{
USED(x);
}
void /*__attribute__((constructor))*/
ignusr1(int restart)
{
struct sigaction sa;
memset(&sa, 0, sizeof sa);
sa.sa_handler = ign;
sigemptyset(&sa.sa_mask);
sigaddset(&sa.sa_mask, SIGUSR1);
if(restart)
sa.sa_flags = SA_RESTART;
sigaction(SIGUSR1, &sa, nil);
}
void
_procsleep(_Procrend *r)
{
sigset_t mask;
/*
* Go to sleep.
*
* Block USR1, set the handler to interrupt system calls,
* unlock the vouslock so our waker can wake us,
* and then suspend.
*/
r->asleep = 1;
r->pid = getpid();
sigprocmask(SIG_SETMASK, nil, &mask);
sigaddset(&mask, SIGUSR1);
sigprocmask(SIG_SETMASK, &mask, nil);
ignusr1(0);
unlock(r->l);
sigdelset(&mask, SIGUSR1);
sigsuspend(&mask);
/*
* We're awake. Make USR1 not interrupt system calls.
*/
ignusr1(1);
assert(r->asleep == 0);
lock(r->l);
}
void
_procwakeup(_Procrend *r)
{
r->asleep = 0;
assert(r->pid >= 1);
kill(r->pid, SIGUSR1);
}
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