eloop.c

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#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>

#ifdef CONFIG_NATIVE_WINDOWS
#include "common.h"
#endif /* CONFIG_NATIVE_WINDOWS */

#include "eloop.h"


struct eloop_sock {
        int sock;
        void *eloop_data;
        void *user_data;
        void (*handler)(int sock, void *eloop_ctx, void *sock_ctx);
};

struct eloop_timeout {
        struct timeval time;
        void *eloop_data;
        void *user_data;
        void (*handler)(void *eloop_ctx, void *sock_ctx);
        struct eloop_timeout *next;
};

struct eloop_signal {
        int sig;
        void *user_data;
        void (*handler)(int sig, void *eloop_ctx, void *signal_ctx);
        int signaled;
};

struct eloop_data {
        void *user_data;

        int max_sock, reader_count;
        struct eloop_sock *readers;

        struct eloop_timeout *timeout;

        int signal_count;
        struct eloop_signal *signals;
        int signaled;
        int pending_terminate;

        int terminate;
        int reader_table_changed;
};

static struct eloop_data eloop;


void eloop_init(void *user_data)
{
        memset(&eloop, 0, sizeof(eloop));
        eloop.user_data = user_data;
}


int eloop_register_read_sock(int sock,
                             void (*handler)(int sock, void *eloop_ctx,
                                             void *sock_ctx),
                             void *eloop_data, void *user_data)
{
        struct eloop_sock *tmp;

        tmp = (struct eloop_sock *)
                realloc(eloop.readers,
                        (eloop.reader_count + 1) * sizeof(struct eloop_sock));
        if (tmp == NULL)
                return -1;

        tmp[eloop.reader_count].sock = sock;
        tmp[eloop.reader_count].eloop_data = eloop_data;
        tmp[eloop.reader_count].user_data = user_data;
        tmp[eloop.reader_count].handler = handler;
        eloop.reader_count++;
        eloop.readers = tmp;
        if (sock > eloop.max_sock)
                eloop.max_sock = sock;
        eloop.reader_table_changed = 1;

        return 0;
}


void eloop_unregister_read_sock(int sock)
{
        int i;

        if (eloop.readers == NULL || eloop.reader_count == 0)
                return;

        for (i = 0; i < eloop.reader_count; i++) {
                if (eloop.readers[i].sock == sock)
                        break;
        }
        if (i == eloop.reader_count)
                return;
        if (i != eloop.reader_count - 1) {
                memmove(&eloop.readers[i], &eloop.readers[i + 1],
                        (eloop.reader_count - i - 1) *
                        sizeof(struct eloop_sock));
        }
        eloop.reader_count--;
        eloop.reader_table_changed = 1;
}


int eloop_register_timeout(unsigned int secs, unsigned int usecs,
                           void (*handler)(void *eloop_ctx, void *timeout_ctx),
                           void *eloop_data, void *user_data)
{
        struct eloop_timeout *timeout, *tmp, *prev;

        timeout = (struct eloop_timeout *) malloc(sizeof(*timeout));
        if (timeout == NULL)
                return -1;
        gettimeofday(&timeout->time, NULL);
        timeout->time.tv_sec += secs;
        timeout->time.tv_usec += usecs;
        while (timeout->time.tv_usec >= 1000000) {
                timeout->time.tv_sec++;
                timeout->time.tv_usec -= 1000000;
        }
        timeout->eloop_data = eloop_data;
        timeout->user_data = user_data;
        timeout->handler = handler;
        timeout->next = NULL;

        if (eloop.timeout == NULL) {
                eloop.timeout = timeout;
                return 0;
        }

        prev = NULL;
        tmp = eloop.timeout;
        while (tmp != NULL) {
                if (timercmp(&timeout->time, &tmp->time, <))
                        break;
                prev = tmp;
                tmp = tmp->next;
        }

        if (prev == NULL) {
                timeout->next = eloop.timeout;
                eloop.timeout = timeout;
        } else {
                timeout->next = prev->next;
                prev->next = timeout;
        }

        return 0;
}


int eloop_cancel_timeout(void (*handler)(void *eloop_ctx, void *sock_ctx),
                         void *eloop_data, void *user_data)
{
        struct eloop_timeout *timeout, *prev, *next;
        int removed = 0;

        prev = NULL;
        timeout = eloop.timeout;
        while (timeout != NULL) {
                next = timeout->next;

                if (timeout->handler == handler &&
                    (timeout->eloop_data == eloop_data ||
                     eloop_data == ELOOP_ALL_CTX) &&
                    (timeout->user_data == user_data ||
                     user_data == ELOOP_ALL_CTX)) {
                        if (prev == NULL)
                                eloop.timeout = next;
                        else
                                prev->next = next;
                        free(timeout);
                        removed++;
                } else
                        prev = timeout;

                timeout = next;
        }

        return removed;
}


#ifndef CONFIG_NATIVE_WINDOWS
static void eloop_handle_alarm(int sig)
{
        fprintf(stderr, "eloop: could not process SIGINT or SIGTERM in two "
                "seconds. Looks like there\n"
                "is a bug that ends up in a busy loop that "
                "prevents clean shutdown.\n"
                "Killing program forcefully.\n");
        exit(1);
}
#endif /* CONFIG_NATIVE_WINDOWS */


static void eloop_handle_signal(int sig)
{
        int i;

#ifndef CONFIG_NATIVE_WINDOWS
        if ((sig == SIGINT || sig == SIGTERM) && !eloop.pending_terminate) {
                /* Use SIGALRM to break out from potential busy loops that
                 * would not allow the program to be killed. */
                eloop.pending_terminate = 1;
                signal(SIGALRM, eloop_handle_alarm);
                alarm(2);
        }
#endif /* CONFIG_NATIVE_WINDOWS */

        eloop.signaled++;
        for (i = 0; i < eloop.signal_count; i++) {
                if (eloop.signals[i].sig == sig) {
                        eloop.signals[i].signaled++;
                        break;
                }
        }
}


static void eloop_process_pending_signals(void)
{
        int i;

        if (eloop.signaled == 0)
                return;
        eloop.signaled = 0;

        if (eloop.pending_terminate) {
#ifndef CONFIG_NATIVE_WINDOWS
                alarm(0);
#endif /* CONFIG_NATIVE_WINDOWS */
                eloop.pending_terminate = 0;
        }

        for (i = 0; i < eloop.signal_count; i++) {
                if (eloop.signals[i].signaled) {
                        eloop.signals[i].signaled = 0;
                        eloop.signals[i].handler(eloop.signals[i].sig,
                                                 eloop.user_data,
                                                 eloop.signals[i].user_data);
                }
        }
}


int eloop_register_signal(int sig,
                          void (*handler)(int sig, void *eloop_ctx,
                                          void *signal_ctx),
                          void *user_data)
{
        struct eloop_signal *tmp;

        tmp = (struct eloop_signal *)
                realloc(eloop.signals,
                        (eloop.signal_count + 1) *
                        sizeof(struct eloop_signal));
        if (tmp == NULL)
                return -1;

        tmp[eloop.signal_count].sig = sig;
        tmp[eloop.signal_count].user_data = user_data;
        tmp[eloop.signal_count].handler = handler;
        tmp[eloop.signal_count].signaled = 0;
        eloop.signal_count++;
        eloop.signals = tmp;
        signal(sig, eloop_handle_signal);

        return 0;
}


void eloop_run(void)
{
        fd_set *rfds;
        int i, res;
        struct timeval tv, now;

        rfds = malloc(sizeof(*rfds));
        if (rfds == NULL) {
                printf("eloop_run - malloc failed\n");
                return;
        }

        while (!eloop.terminate &&
                (eloop.timeout || eloop.reader_count > 0)) {
                if (eloop.timeout) {
                        gettimeofday(&now, NULL);
                        if (timercmp(&now, &eloop.timeout->time, <))
                                timersub(&eloop.timeout->time, &now, &tv);
                        else
                                tv.tv_sec = tv.tv_usec = 0;
#if 0
                        printf("next timeout in %lu.%06lu sec\n",
                               tv.tv_sec, tv.tv_usec);
#endif
                }

                FD_ZERO(rfds);
                for (i = 0; i < eloop.reader_count; i++)
                        FD_SET(eloop.readers[i].sock, rfds);
                res = select(eloop.max_sock + 1, rfds, NULL, NULL,
                             eloop.timeout ? &tv : NULL);
                if (res < 0 && errno != EINTR) {
                        perror("select");
                        free(rfds);
                        return;
                }
                eloop_process_pending_signals();

                /* check if some registered timeouts have occurred */
                if (eloop.timeout) {
                        struct eloop_timeout *tmp;

                        gettimeofday(&now, NULL);
                        if (!timercmp(&now, &eloop.timeout->time, <)) {
                                tmp = eloop.timeout;
                                eloop.timeout = eloop.timeout->next;
                                tmp->handler(tmp->eloop_data,
                                             tmp->user_data);
                                free(tmp);
                        }

                }

                if (res <= 0)
                        continue;

                eloop.reader_table_changed = 0;
                for (i = 0; i < eloop.reader_count; i++) {
                        if (FD_ISSET(eloop.readers[i].sock, rfds)) {
                                eloop.readers[i].handler(
                                        eloop.readers[i].sock,
                                        eloop.readers[i].eloop_data,
                                        eloop.readers[i].user_data);
                                if (eloop.reader_table_changed)
                                        break;
                        }
                }
        }

        free(rfds);
}


void eloop_terminate(void)
{
        eloop.terminate = 1;
}


void eloop_destroy(void)
{
        struct eloop_timeout *timeout, *prev;

        timeout = eloop.timeout;
        while (timeout != NULL) {
                prev = timeout;
                timeout = timeout->next;
                free(prev);
        }
        free(eloop.readers);
        free(eloop.signals);
}


int eloop_terminated(void)
{
        return eloop.terminate;
}

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