dcc38d1cce
Port qemu-kvm's signalfd compat code.
commit 5a7fdd0abd7cd24dac205317a4195446ab8748b5
Author: Anthony Liguori <aliguori@us.ibm.com>
Date: Wed May 7 11:55:47 2008 -0500
Use signalfd() in io-thread
This patch reworks the IO thread to use signalfd() instead of sigtimedwait()
This will eliminate the need to use SIGIO everywhere.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
118 lines
2.3 KiB
C
118 lines
2.3 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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*/
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#include "qemu-common.h"
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#include "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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int err;
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sigset_t all;
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sigfillset(&all);
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sigprocmask(SIG_BLOCK, &all, NULL);
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do {
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siginfo_t siginfo;
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err = sigwaitinfo(&info->mask, &siginfo);
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if (err == -1 && errno == EINTR) {
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err = 0;
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continue;
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}
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if (err > 0) {
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char buffer[128];
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size_t offset = 0;
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memcpy(buffer, &err, sizeof(err));
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while (offset < sizeof(buffer)) {
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ssize_t len;
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len = write(info->fd, 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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err = -1;
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break;
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}
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offset += len;
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}
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}
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} while (err >= 0);
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return NULL;
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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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