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https://github.com/qemu/qemu.git
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f627aab1cc
Start introducing AioContext, which will let us remove globals from aio.c/async.c, and introduce multiple I/O threads. The bottom half functions now take an additional AioContext argument. A bottom half is created with a specific AioContext that remains the same throughout the lifetime. qemu_bh_new is just a wrapper that uses a global context. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
199 lines
5.5 KiB
C
199 lines
5.5 KiB
C
/*
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* QEMU System Emulator - managing I/O handler
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*
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* Copyright (c) 2003-2008 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "config-host.h"
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#include "qemu-common.h"
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#include "qemu-char.h"
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#include "qemu-queue.h"
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#include "qemu-aio.h"
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#include "main-loop.h"
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#ifndef _WIN32
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#include <sys/wait.h>
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#endif
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typedef struct IOHandlerRecord {
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IOCanReadHandler *fd_read_poll;
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IOHandler *fd_read;
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IOHandler *fd_write;
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void *opaque;
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QLIST_ENTRY(IOHandlerRecord) next;
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int fd;
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bool deleted;
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} IOHandlerRecord;
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static QLIST_HEAD(, IOHandlerRecord) io_handlers =
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QLIST_HEAD_INITIALIZER(io_handlers);
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/* XXX: fd_read_poll should be suppressed, but an API change is
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necessary in the character devices to suppress fd_can_read(). */
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int qemu_set_fd_handler2(int fd,
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IOCanReadHandler *fd_read_poll,
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IOHandler *fd_read,
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IOHandler *fd_write,
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void *opaque)
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{
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IOHandlerRecord *ioh;
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assert(fd >= 0);
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if (!fd_read && !fd_write) {
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QLIST_FOREACH(ioh, &io_handlers, next) {
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if (ioh->fd == fd) {
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ioh->deleted = 1;
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break;
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}
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}
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} else {
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QLIST_FOREACH(ioh, &io_handlers, next) {
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if (ioh->fd == fd)
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goto found;
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}
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ioh = g_malloc0(sizeof(IOHandlerRecord));
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QLIST_INSERT_HEAD(&io_handlers, ioh, next);
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found:
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ioh->fd = fd;
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ioh->fd_read_poll = fd_read_poll;
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ioh->fd_read = fd_read;
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ioh->fd_write = fd_write;
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ioh->opaque = opaque;
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ioh->deleted = 0;
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qemu_notify_event();
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}
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return 0;
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}
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int qemu_set_fd_handler(int fd,
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IOHandler *fd_read,
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IOHandler *fd_write,
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void *opaque)
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{
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return qemu_set_fd_handler2(fd, NULL, fd_read, fd_write, opaque);
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}
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void qemu_iohandler_fill(int *pnfds, fd_set *readfds, fd_set *writefds, fd_set *xfds)
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{
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IOHandlerRecord *ioh;
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QLIST_FOREACH(ioh, &io_handlers, next) {
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if (ioh->deleted)
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continue;
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if (ioh->fd_read &&
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(!ioh->fd_read_poll ||
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ioh->fd_read_poll(ioh->opaque) != 0)) {
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FD_SET(ioh->fd, readfds);
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if (ioh->fd > *pnfds)
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*pnfds = ioh->fd;
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}
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if (ioh->fd_write) {
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FD_SET(ioh->fd, writefds);
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if (ioh->fd > *pnfds)
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*pnfds = ioh->fd;
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}
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}
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}
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void qemu_iohandler_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds, int ret)
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{
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if (ret > 0) {
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IOHandlerRecord *pioh, *ioh;
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QLIST_FOREACH_SAFE(ioh, &io_handlers, next, pioh) {
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if (!ioh->deleted && ioh->fd_read && FD_ISSET(ioh->fd, readfds)) {
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ioh->fd_read(ioh->opaque);
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}
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if (!ioh->deleted && ioh->fd_write && FD_ISSET(ioh->fd, writefds)) {
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ioh->fd_write(ioh->opaque);
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}
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/* Do this last in case read/write handlers marked it for deletion */
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if (ioh->deleted) {
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QLIST_REMOVE(ioh, next);
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g_free(ioh);
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}
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}
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}
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}
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/* reaping of zombies. right now we're not passing the status to
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anyone, but it would be possible to add a callback. */
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#ifndef _WIN32
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typedef struct ChildProcessRecord {
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int pid;
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QLIST_ENTRY(ChildProcessRecord) next;
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} ChildProcessRecord;
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static QLIST_HEAD(, ChildProcessRecord) child_watches =
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QLIST_HEAD_INITIALIZER(child_watches);
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static QEMUBH *sigchld_bh;
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static void sigchld_handler(int signal)
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{
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qemu_bh_schedule(sigchld_bh);
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}
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static void sigchld_bh_handler(void *opaque)
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{
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ChildProcessRecord *rec, *next;
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QLIST_FOREACH_SAFE(rec, &child_watches, next, next) {
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if (waitpid(rec->pid, NULL, WNOHANG) == rec->pid) {
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QLIST_REMOVE(rec, next);
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g_free(rec);
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}
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}
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}
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static void qemu_init_child_watch(void)
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{
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struct sigaction act;
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sigchld_bh = qemu_bh_new(sigchld_bh_handler, NULL);
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act.sa_handler = sigchld_handler;
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act.sa_flags = SA_NOCLDSTOP;
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sigaction(SIGCHLD, &act, NULL);
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}
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int qemu_add_child_watch(pid_t pid)
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{
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ChildProcessRecord *rec;
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if (!sigchld_bh) {
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qemu_init_child_watch();
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}
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QLIST_FOREACH(rec, &child_watches, next) {
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if (rec->pid == pid) {
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return 1;
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}
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}
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rec = g_malloc0(sizeof(ChildProcessRecord));
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rec->pid = pid;
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QLIST_INSERT_HEAD(&child_watches, rec, next);
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return 0;
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}
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#endif
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