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#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <sys/signalfd.h>
#include <sys/wait.h>
#include "triton.h"
#include "spinlock.h"
#include "log.h"
#include "sigchld.h"
static LIST_HEAD(handlers);
static int refs;
static int sleeping = 1;
static pthread_mutex_t handlers_lock = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t refs_lock = PTHREAD_MUTEX_INITIALIZER;
static struct triton_context_t sigchld_ctx;
static void sigchld_handler(void *arg)
{
struct sigchld_handler_t *h, *h0;
pid_t pid;
int status;
while (1) {
pid = waitpid(0, &status, WNOHANG);
pthread_mutex_lock(&handlers_lock);
if (pid == 0 || (pid == -1 && errno == ECHILD)) {
sleeping = 1;
pthread_mutex_unlock(&handlers_lock);
return;
} else if (pid < 0) {
pthread_mutex_unlock(&handlers_lock);
log_error("sigchld: waitpid: %s\n", strerror(errno));
return;
}
h0 = NULL;
list_for_each_entry(h, &handlers, entry) {
if (h->pid == pid) {
h0 = h;
pthread_mutex_lock(&h0->lock);
break;
}
}
pthread_mutex_unlock(&handlers_lock);
if (h0) {
h0->handler(h0, WEXITSTATUS(status));
list_del(&h0->entry);
h0->pid = 0;
pthread_mutex_unlock(&h0->lock);
}
}
}
void __export sigchld_register_handler(struct sigchld_handler_t *h)
{
pthread_mutex_init(&h->lock, NULL);
pthread_mutex_lock(&handlers_lock);
list_add_tail(&h->entry, &handlers);
pthread_mutex_unlock(&handlers_lock);
}
void __export sigchld_unregister_handler(struct sigchld_handler_t *h)
{
pthread_mutex_lock(&handlers_lock);
pthread_mutex_lock(&h->lock);
if (h->pid) {
list_del(&h->entry);
h->pid = 0;
}
pthread_mutex_unlock(&h->lock);
pthread_mutex_unlock(&handlers_lock);
}
void __export sigchld_lock()
{
sigset_t set;
pthread_mutex_lock(&refs_lock);
if (refs == 0) {
sigemptyset(&set);
sigaddset(&set, SIGCHLD);
sigprocmask(SIG_BLOCK, &set, NULL);
}
++refs;
pthread_mutex_unlock(&refs_lock);
}
void __export sigchld_unlock()
{
sigset_t set;
pthread_mutex_lock(&refs_lock);
if (refs == 1) {
sigemptyset(&set);
sigaddset(&set, SIGCHLD);
sigprocmask(SIG_UNBLOCK, &set, NULL);
}
--refs;
pthread_mutex_unlock(&refs_lock);
}
static void sigchld(int num)
{
int s;
pthread_mutex_lock(&handlers_lock);
s = sleeping;
sleeping = 0;
pthread_mutex_unlock(&handlers_lock);
if (s)
triton_context_call(&sigchld_ctx, sigchld_handler, NULL);
}
static void __init init(void)
{
struct sigaction sa_sigchld = {
.sa_handler = sigchld,
.sa_flags = SA_NOCLDSTOP,
};
if (sigaction(SIGCHLD, &sa_sigchld, NULL)) {
fprintf(stderr, "sigchld: sigaction: %s\n", strerror(errno));
return;
}
triton_context_register(&sigchld_ctx, NULL);
}
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