139 lines
2.8 KiB
C
139 lines
2.8 KiB
C
/*
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* signalfd/eventfd compatibility
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*
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* Copyright IBM, Corp. 2008
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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* Contributions after 2012-01-13 are licensed under the terms of the
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* GNU GPL, version 2 or (at your option) any later version.
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*/
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#include "qemu-common.h"
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#include "qemu/compatfd.h"
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#include <sys/syscall.h>
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#include <pthread.h>
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struct sigfd_compat_info
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{
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sigset_t mask;
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int fd;
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};
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static void *sigwait_compat(void *opaque)
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{
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struct sigfd_compat_info *info = opaque;
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sigset_t all;
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sigfillset(&all);
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pthread_sigmask(SIG_BLOCK, &all, NULL);
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while (1) {
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int sig;
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int err;
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err = sigwait(&info->mask, &sig);
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if (err != 0) {
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if (errno == EINTR) {
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continue;
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} else {
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return NULL;
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}
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} else {
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struct qemu_signalfd_siginfo buffer;
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size_t offset = 0;
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memset(&buffer, 0, sizeof(buffer));
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buffer.ssi_signo = sig;
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while (offset < sizeof(buffer)) {
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ssize_t len;
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len = write(info->fd, (char *)&buffer + offset,
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sizeof(buffer) - offset);
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if (len == -1 && errno == EINTR)
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continue;
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if (len <= 0) {
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return NULL;
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}
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offset += len;
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}
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}
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}
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}
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static int qemu_signalfd_compat(const sigset_t *mask)
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{
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pthread_attr_t attr;
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pthread_t tid;
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struct sigfd_compat_info *info;
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int fds[2];
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info = malloc(sizeof(*info));
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if (info == NULL) {
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errno = ENOMEM;
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return -1;
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}
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if (pipe(fds) == -1) {
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free(info);
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return -1;
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}
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qemu_set_cloexec(fds[0]);
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qemu_set_cloexec(fds[1]);
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memcpy(&info->mask, mask, sizeof(*mask));
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info->fd = fds[1];
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pthread_attr_init(&attr);
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pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
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pthread_create(&tid, &attr, sigwait_compat, info);
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pthread_attr_destroy(&attr);
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return fds[0];
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}
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int qemu_signalfd(const sigset_t *mask)
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{
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#if defined(CONFIG_SIGNALFD)
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int ret;
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ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);
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if (ret != -1) {
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qemu_set_cloexec(ret);
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return ret;
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}
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#endif
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return qemu_signalfd_compat(mask);
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}
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bool qemu_signalfd_available(void)
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{
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#ifdef CONFIG_SIGNALFD
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sigset_t mask;
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int fd;
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bool ok;
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sigemptyset(&mask);
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errno = 0;
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fd = syscall(SYS_signalfd, -1, &mask, _NSIG / 8);
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ok = (errno != ENOSYS);
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if (fd >= 0) {
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close(fd);
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}
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return ok;
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#else
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return false;
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#endif
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}
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