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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.
- *
- */
- #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;
- 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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