Files
sesimos/src/async.c

114 lines
2.7 KiB
C

/**
* Sesimos - secure, simple, modern web server
* @brief Async handler
* @file src/async.c
* @author Lorenz Stechauner
* @date 2022-12-28
*/
#include "async.h"
#include "logger.h"
#include <poll.h>
#include <signal.h>
#include <errno.h>
#include <memory.h>
#include <pthread.h>
typedef struct {
int fd;
short events;
int flags;
void (*cb)(void *);
void *arg;
void (*err_cb)(void *);
void *err_arg;
} evt_listen_t;
typedef struct {
int n;
evt_listen_t q[256];
} listen_queue_t;
static listen_queue_t listen1, listen2, *listen = &listen1;
static volatile sig_atomic_t alive = 1;
static pthread_t thread = -1;
static int async_add_to_queue(evt_listen_t *evt) {
// TODO locking
memcpy(&listen->q[listen->n++], evt, sizeof(*evt));
if (thread != -1) pthread_kill(thread, SIGUSR1);
return 0;
}
int async(int fd, short events, int flags, void cb(void *), void *arg, void err_cb(void *), void *err_arg) {
evt_listen_t evt = {
.fd = fd,
.events = events,
.flags = flags,
.cb = cb,
.arg = arg,
.err_cb = err_cb,
.err_arg = err_arg,
};
return async_add_to_queue(&evt);
}
void async_thread(void) {
int num_fds;
struct pollfd fds[256]; // TODO dynamic
thread = pthread_self();
// main event loop
while (alive) {
// swap listen queue
listen_queue_t *l = listen;
listen = (listen == &listen1) ? &listen2 : &listen1;
// fill fds with newly added queue entries
for (num_fds = 0; num_fds < l->n; num_fds++) {
fds[num_fds].fd = l->q[num_fds].fd;
fds[num_fds].events = l->q[num_fds].events;
}
if (poll(fds, num_fds, -1) < 0) {
if (errno == EINTR) {
// interrupt
errno = 0;
} else {
// other error
critical("Unable to poll for events");
return;
}
}
for (int i = 0; i < num_fds; i++) {
evt_listen_t *e = &l->q[i];
if (fds[i].revents & e->events) {
// specified event(s) occurred
e->cb(e->arg);
if (e->flags & ASYNC_KEEP)
async_add_to_queue(e);
} else if (fds[i].revents & (POLLERR | POLLHUP | POLLNVAL)) {
// error occurred
e->err_cb(e->err_arg);
} else {
// no event occurred
async_add_to_queue(e);
}
// reset errno to prevent strange behaviour
errno = 0;
}
// reset size of queue
l->n = 0;
}
}
void async_stop(void) {
alive = 0;
}