Archipelago » qemu

/*

 * signalfd/eventfd compatibility

 *

 * Copyright IBM, Corp. 2008

 *

 * Authors:

 *  Anthony Liguori   <aliguori@us.ibm.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2.  See

 * the COPYING file in the top-level directory.

 *

 */

#include "qemu-common.h"

#include "compatfd.h"

#include <sys/syscall.h>

#include <pthread.h>

struct sigfd_compat_info

{

    sigset_t mask;

    int fd;

};

static void *sigwait_compat(void *opaque)

{

    struct sigfd_compat_info *info = opaque;

    int err;

    sigset_t all;

    sigfillset(&all);

    sigprocmask(SIG_BLOCK, &all, NULL);

    do {

        siginfo_t siginfo;

        err = sigwaitinfo(&info->mask, &siginfo);

        if (err == -1 && errno == EINTR) {

            err = 0;

            continue;

        }

        if (err > 0) {

            char buffer[128];

            size_t offset = 0;

            memcpy(buffer, &err, sizeof(err));

            while (offset < sizeof(buffer)) {

                ssize_t len;

                len = write(info->fd, buffer + offset,

                            sizeof(buffer) - offset);

                if (len == -1 && errno == EINTR)

                    continue;

                if (len <= 0) {

                    err = -1;

                    break;

                }

                offset += len;

            }

        }

    } while (err >= 0);

    return NULL;

}

static int qemu_signalfd_compat(const sigset_t *mask)

{

    pthread_attr_t attr;

    pthread_t tid;

    struct sigfd_compat_info *info;

    int fds[2];

    info = malloc(sizeof(*info));

    if (info == NULL) {

        errno = ENOMEM;

        return -1;

    }

    if (pipe(fds) == -1) {

        free(info);

        return -1;

    }

    memcpy(&info->mask, mask, sizeof(*mask));

    info->fd = fds[1];

    pthread_attr_init(&attr);

    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);

    pthread_create(&tid, &attr, sigwait_compat, info);

    pthread_attr_destroy(&attr);

    return fds[0];

}

int qemu_signalfd(const sigset_t *mask)

{

#if defined(SYS_signalfd)

    int ret;

    ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);

    if (!(ret == -1 && errno == ENOSYS))

        return ret;

#endif

    return qemu_signalfd_compat(mask);

}

int qemu_eventfd(int *fds)

{

#if defined(SYS_eventfd)

    int ret;

    ret = syscall(SYS_eventfd, 0);

    if (ret >= 0) {

        fds[0] = fds[1] = ret;

        return 0;

    } else if (!(ret == -1 && errno == ENOSYS))

        return ret;

#endif

    return pipe(fds);

}