Date: Fri, 11 Jun 2004 01:09:07 -0700 From: Sean McNeil <sean@mcneil.com> To: Daniel Eischen <eischen@vigrid.com> Cc: freebsd-threads@freebsd.org Subject: Re: signal handler priority issue Message-ID: <1086941347.10026.33.camel@server.mcneil.com> In-Reply-To: <1086941096.10026.31.camel@server.mcneil.com> References: <Pine.GSO.4.10.10406110313540.3491-100000@pcnet5.pcnet.com> <1086941096.10026.31.camel@server.mcneil.com>
next in thread | previous in thread | raw e-mail | index | archive | help
OOOPPPSSS!!!! typo. Ignore.
On Fri, 2004-06-11 at 01:04, Sean McNeil wrote:
> Variation that doesn't work:
>
> /*
> * test_sr.c
> *
> * Demonstrate use of signals & semaphores for suspending and
> * resuming threads.
> */
> #include <errno.h>
> #include <pthread.h>
> #include <semaphore.h>
> #include <signal.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <ucontext.h>
> #include <unistd.h>
>
> #ifndef NUM_THREADS
> #define NUM_THREADS 5
> #endif
>
> static sem_t semaphore;
> static int done = 0;
> static pthread_t tids[NUM_THREADS];
>
>
> static void
> errno_abort(char *msg)
> {
> printf("%s, errno %d\n", msg, errno);
> abort();
> }
>
> static void
> err_abort(int status, char *msg)
> {
> printf("%s, status %d\n", msg, status);
> abort();
> }
>
> static void
> sighandler1(int sig, siginfo_t *info, ucontext_t *ucp)
> {
> sigset_t mask;
>
> printf("Thread %p pausing.\n", pthread_self());
> sigfillset(&mask);
> sigdelset(&mask, SIGUSR2);
> sem_post(&semaphore);
> sigsuspend(&mask);
> printf("Thread %p successfully resumed.\n", pthread_self());
> }
>
> static void
> sighandler2(int sig, siginfo_t *info, ucontext_t *ucp)
> {
> printf("Thread %p got resume signal.\n", pthread_self());
> }
>
> /*
> * Thread start routine to wait on a semaphore.
> */
> static void *
> worker(void *arg)
> {
> int num = (int)arg;
> int x;
>
> num = (int)arg;
> x = num * 10;
>
> printf ("Thread %d starting.\n", num);
> while (!done) {
> x = x + 1;
> x = x - 1;
> }
> printf("Thread %d stopping.\n", num);
>
> return (NULL);
> }
>
> static void
> pause_threads(void)
> {
> int i;
>
> printf("Master: pausing all threads.\n");
> for (i = 0; i < NUM_THREADS; i++) {
> pthread_kill(tids[i], SIGUSR1);
> if (sem_wait(&semaphore) == -1)
> errno_abort("Wait on semaphore");
> }
> }
>
> static void
> resume_threads(void)
> {
> int i;
>
> printf("Master: resuming all threads.\n");
> for (i = 0; i < NUM_THREADS; i++) {
> pthread_kill(tids[i], SIGUSR2);
> }
> }
>
> int
> main(int argc, char *argv[])
> {
> struct sigaction act;
> int status;
> int i;
>
> if (sem_init (&semaphore, 0, 0) == -1)
> errno_abort ("Init semaphore");
>
> /* Mask all signals while in the signal handler. */
> sigfillset(&act.sa_mask);
> act.sa_flags = SA_RESTART;
>
> act.sa_handler = sighandler1;
> sigaction(SIGUSR1, &act, NULL);
>
> act.sa_handler = sighandler1;
> sigaction(SIGUSR2, &act, NULL);
>
> /*
> * Create some worker threads.
> */
> for (i = 0; i < NUM_THREADS; i++) {
> status = pthread_create(&tids[i], NULL, worker, (void *)i);
> if (status != 0)
> err_abort (status, "Create thread");
> }
>
> sleep (1);
>
> for (i = 0; i < 5; i++) {
> pause_threads();
> resume_threads();
> }
>
> done = 1;
>
> /*
> * Wait for all threads to complete.
> */
> for (i = 0; i < NUM_THREADS; i++) {
> status = pthread_join(tids[i], NULL);
> if (status != 0)
> err_abort(status, "Join thread");
> }
> return (0);
> }
>
>
>
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?1086941347.10026.33.camel>