qemu/iohandler.c
Paolo Bonzini be08e65e01 Revert to a hand-made select loop
This reverts commit c82dc29a91
and 4d88a2ac86.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2011-10-21 18:14:30 +02:00

195 lines
5.5 KiB
C

/*
* QEMU System Emulator - managing I/O handler
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "config-host.h"
#include "qemu-common.h"
#include "qemu-char.h"
#include "qemu-queue.h"
#include "main-loop.h"
#ifndef _WIN32
#include <sys/wait.h>
#endif
typedef struct IOHandlerRecord {
int fd;
IOCanReadHandler *fd_read_poll;
IOHandler *fd_read;
IOHandler *fd_write;
int deleted;
void *opaque;
QLIST_ENTRY(IOHandlerRecord) next;
} IOHandlerRecord;
static QLIST_HEAD(, IOHandlerRecord) io_handlers =
QLIST_HEAD_INITIALIZER(io_handlers);
/* XXX: fd_read_poll should be suppressed, but an API change is
necessary in the character devices to suppress fd_can_read(). */
int qemu_set_fd_handler2(int fd,
IOCanReadHandler *fd_read_poll,
IOHandler *fd_read,
IOHandler *fd_write,
void *opaque)
{
IOHandlerRecord *ioh;
if (!fd_read && !fd_write) {
QLIST_FOREACH(ioh, &io_handlers, next) {
if (ioh->fd == fd) {
ioh->deleted = 1;
break;
}
}
} else {
QLIST_FOREACH(ioh, &io_handlers, next) {
if (ioh->fd == fd)
goto found;
}
ioh = g_malloc0(sizeof(IOHandlerRecord));
QLIST_INSERT_HEAD(&io_handlers, ioh, next);
found:
ioh->fd = fd;
ioh->fd_read_poll = fd_read_poll;
ioh->fd_read = fd_read;
ioh->fd_write = fd_write;
ioh->opaque = opaque;
ioh->deleted = 0;
}
return 0;
}
int qemu_set_fd_handler(int fd,
IOHandler *fd_read,
IOHandler *fd_write,
void *opaque)
{
return qemu_set_fd_handler2(fd, NULL, fd_read, fd_write, opaque);
}
void qemu_iohandler_fill(int *pnfds, fd_set *readfds, fd_set *writefds, fd_set *xfds)
{
IOHandlerRecord *ioh;
QLIST_FOREACH(ioh, &io_handlers, next) {
if (ioh->deleted)
continue;
if (ioh->fd_read &&
(!ioh->fd_read_poll ||
ioh->fd_read_poll(ioh->opaque) != 0)) {
FD_SET(ioh->fd, readfds);
if (ioh->fd > *pnfds)
*pnfds = ioh->fd;
}
if (ioh->fd_write) {
FD_SET(ioh->fd, writefds);
if (ioh->fd > *pnfds)
*pnfds = ioh->fd;
}
}
}
void qemu_iohandler_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds, int ret)
{
if (ret > 0) {
IOHandlerRecord *pioh, *ioh;
QLIST_FOREACH_SAFE(ioh, &io_handlers, next, pioh) {
if (!ioh->deleted && ioh->fd_read && FD_ISSET(ioh->fd, readfds)) {
ioh->fd_read(ioh->opaque);
}
if (!ioh->deleted && ioh->fd_write && FD_ISSET(ioh->fd, writefds)) {
ioh->fd_write(ioh->opaque);
}
/* Do this last in case read/write handlers marked it for deletion */
if (ioh->deleted) {
QLIST_REMOVE(ioh, next);
g_free(ioh);
}
}
}
}
/* reaping of zombies. right now we're not passing the status to
anyone, but it would be possible to add a callback. */
#ifndef _WIN32
typedef struct ChildProcessRecord {
int pid;
QLIST_ENTRY(ChildProcessRecord) next;
} ChildProcessRecord;
static QLIST_HEAD(, ChildProcessRecord) child_watches =
QLIST_HEAD_INITIALIZER(child_watches);
static QEMUBH *sigchld_bh;
static void sigchld_handler(int signal)
{
qemu_bh_schedule(sigchld_bh);
}
static void sigchld_bh_handler(void *opaque)
{
ChildProcessRecord *rec, *next;
QLIST_FOREACH_SAFE(rec, &child_watches, next, next) {
if (waitpid(rec->pid, NULL, WNOHANG) == rec->pid) {
QLIST_REMOVE(rec, next);
g_free(rec);
}
}
}
static void qemu_init_child_watch(void)
{
struct sigaction act;
sigchld_bh = qemu_bh_new(sigchld_bh_handler, NULL);
act.sa_handler = sigchld_handler;
act.sa_flags = SA_NOCLDSTOP;
sigaction(SIGCHLD, &act, NULL);
}
int qemu_add_child_watch(pid_t pid)
{
ChildProcessRecord *rec;
if (!sigchld_bh) {
qemu_init_child_watch();
}
QLIST_FOREACH(rec, &child_watches, next) {
if (rec->pid == pid) {
return 1;
}
}
rec = g_malloc0(sizeof(ChildProcessRecord));
rec->pid = pid;
QLIST_INSERT_HEAD(&child_watches, rec, next);
return 0;
}
#endif