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/*
* 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.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include "qemu-common.h"
#include "qemu/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;
sigset_t all;
sigfillset(&all);
pthread_sigmask(SIG_BLOCK, &all, NULL);
while (1) {
int sig;
int err;
err = sigwait(&info->mask, &sig);
if (err != 0) {
if (errno == EINTR) {
continue;
} else {
return NULL;
}
} else {
struct qemu_signalfd_siginfo buffer;
size_t offset = 0;
memset(&buffer, 0, sizeof(buffer));
buffer.ssi_signo = sig;
while (offset < sizeof(buffer)) {
ssize_t len;
len = write(info->fd, (char *)&buffer + offset,
sizeof(buffer) - offset);
if (len == -1 && errno == EINTR)
continue;
if (len <= 0) {
return NULL;
}
offset += len;
}
}
}
}
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;
}
qemu_set_cloexec(fds[0]);
qemu_set_cloexec(fds[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(CONFIG_SIGNALFD)
int ret;
ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);
if (ret != -1) {
qemu_set_cloexec(ret);
return ret;
}
#endif
return qemu_signalfd_compat(mask);
}
bool qemu_signalfd_available(void)
{
#ifdef CONFIG_SIGNALFD
sigset_t mask;
int fd;
bool ok;
sigemptyset(&mask);
errno = 0;
fd = syscall(SYS_signalfd, -1, &mask, _NSIG / 8);
ok = (errno != ENOSYS);
if (fd >= 0) {
close(fd);
}
return ok;
#else
return false;
#endif
}
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