qemu/util/compatfd.c
Kacper Słomiński 6bd17dccb6 util/compatfd.c: use libc signalfd wrapper instead of raw syscall
This allows the use of native signalfd instead of the sigtimedwait
based emulation on systems other than Linux.

Signed-off-by: Kacper Słomiński <kacper.slominski72@gmail.com>
Message-Id: <20210905011621.200785-1-kacper.slominski72@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-10-13 10:47:49 +02:00

107 lines
2.2 KiB
C

/*
* 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/osdep.h"
#include "qemu/thread.h"
#if defined(CONFIG_SIGNALFD)
#include <sys/signalfd.h>
#endif
struct sigfd_compat_info {
sigset_t mask;
int fd;
};
static void *sigwait_compat(void *opaque)
{
struct sigfd_compat_info *info = opaque;
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)
{
struct sigfd_compat_info *info;
QemuThread thread;
int fds[2];
info = g_malloc(sizeof(*info));
if (pipe(fds) == -1) {
g_free(info);
return -1;
}
qemu_set_cloexec(fds[0]);
qemu_set_cloexec(fds[1]);
memcpy(&info->mask, mask, sizeof(*mask));
info->fd = fds[1];
qemu_thread_create(&thread, "signalfd_compat", sigwait_compat, info,
QEMU_THREAD_DETACHED);
return fds[0];
}
int qemu_signalfd(const sigset_t *mask)
{
#if defined(CONFIG_SIGNALFD)
int ret;
ret = signalfd(-1, mask, SFD_CLOEXEC);
if (ret != -1) {
return ret;
}
#endif
return qemu_signalfd_compat(mask);
}