When chardev is multiplexed (mux=on) there are a lot of cases where CHR_EVENT_OPENED/CHR_EVENT_CLOSED events pairing (expected from frontend side) is broken. There are either generation of multiple repeated or extra CHR_EVENT_OPENED events, or CHR_EVENT_CLOSED just isn't generated at all. This is mostly because 'qemu_chr_fe_set_handlers()' function makes its own (and often wrong) implicit decision on updated frontend state and invokes 'fd_event' callback with 'CHR_EVENT_OPENED'. And even worse, it doesn't do symmetric action in opposite direction, as someone may expect (i.e. it doesn't invoke previously set 'fd_event' with 'CHR_EVENT_CLOSED'). Muxed chardev uses trick by calling this function again to replace callback handlers with its own ones, but it doesn't account for such side effect. Fix that using extended version of this function with added argument for disabling side effect and keep original function for compatibility with lots of frontends already using this interface and being "tolerant" to its side effects. One more source of event duplication is just line of code in char-mux.c, which does far more than comment above says (obvious fix). Signed-off-by: Artem Pisarenko <artem.k.pisarenko@gmail.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <7dde6abbd21682857f8294644013173c0b9949b3.1541507990.git.artem.k.pisarenko@gmail.com> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
391 lines
9.5 KiB
C
391 lines
9.5 KiB
C
/*
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* QEMU System Emulator
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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 "qemu/osdep.h"
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#include "qemu/error-report.h"
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#include "qapi/error.h"
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#include "qapi/qmp/qerror.h"
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#include "sysemu/replay.h"
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#include "chardev/char-fe.h"
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#include "chardev/char-io.h"
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#include "chardev/char-mux.h"
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int qemu_chr_fe_write(CharBackend *be, const uint8_t *buf, int len)
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{
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Chardev *s = be->chr;
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if (!s) {
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return 0;
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}
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return qemu_chr_write(s, buf, len, false);
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}
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int qemu_chr_fe_write_all(CharBackend *be, const uint8_t *buf, int len)
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{
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Chardev *s = be->chr;
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if (!s) {
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return 0;
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}
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return qemu_chr_write(s, buf, len, true);
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}
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int qemu_chr_fe_read_all(CharBackend *be, uint8_t *buf, int len)
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{
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Chardev *s = be->chr;
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int offset = 0;
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int res;
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if (!s || !CHARDEV_GET_CLASS(s)->chr_sync_read) {
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return 0;
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}
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if (qemu_chr_replay(s) && replay_mode == REPLAY_MODE_PLAY) {
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return replay_char_read_all_load(buf);
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}
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while (offset < len) {
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retry:
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res = CHARDEV_GET_CLASS(s)->chr_sync_read(s, buf + offset,
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len - offset);
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if (res == -1 && errno == EAGAIN) {
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g_usleep(100);
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goto retry;
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}
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if (res == 0) {
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break;
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}
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if (res < 0) {
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if (qemu_chr_replay(s) && replay_mode == REPLAY_MODE_RECORD) {
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replay_char_read_all_save_error(res);
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}
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return res;
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}
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offset += res;
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}
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if (qemu_chr_replay(s) && replay_mode == REPLAY_MODE_RECORD) {
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replay_char_read_all_save_buf(buf, offset);
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}
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return offset;
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}
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int qemu_chr_fe_ioctl(CharBackend *be, int cmd, void *arg)
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{
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Chardev *s = be->chr;
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int res;
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if (!s || !CHARDEV_GET_CLASS(s)->chr_ioctl || qemu_chr_replay(s)) {
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res = -ENOTSUP;
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} else {
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res = CHARDEV_GET_CLASS(s)->chr_ioctl(s, cmd, arg);
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}
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return res;
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}
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int qemu_chr_fe_get_msgfd(CharBackend *be)
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{
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Chardev *s = be->chr;
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int fd;
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int res = (qemu_chr_fe_get_msgfds(be, &fd, 1) == 1) ? fd : -1;
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if (s && qemu_chr_replay(s)) {
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error_report("Replay: get msgfd is not supported "
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"for serial devices yet");
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exit(1);
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}
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return res;
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}
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int qemu_chr_fe_get_msgfds(CharBackend *be, int *fds, int len)
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{
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Chardev *s = be->chr;
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if (!s) {
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return -1;
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}
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return CHARDEV_GET_CLASS(s)->get_msgfds ?
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CHARDEV_GET_CLASS(s)->get_msgfds(s, fds, len) : -1;
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}
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int qemu_chr_fe_set_msgfds(CharBackend *be, int *fds, int num)
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{
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Chardev *s = be->chr;
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if (!s) {
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return -1;
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}
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return CHARDEV_GET_CLASS(s)->set_msgfds ?
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CHARDEV_GET_CLASS(s)->set_msgfds(s, fds, num) : -1;
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}
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void qemu_chr_fe_accept_input(CharBackend *be)
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{
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Chardev *s = be->chr;
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if (!s) {
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return;
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}
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if (CHARDEV_GET_CLASS(s)->chr_accept_input) {
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CHARDEV_GET_CLASS(s)->chr_accept_input(s);
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}
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qemu_notify_event();
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}
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void qemu_chr_fe_printf(CharBackend *be, const char *fmt, ...)
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{
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char buf[CHR_READ_BUF_LEN];
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va_list ap;
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va_start(ap, fmt);
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vsnprintf(buf, sizeof(buf), fmt, ap);
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/* XXX this blocks entire thread. Rewrite to use
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* qemu_chr_fe_write and background I/O callbacks */
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qemu_chr_fe_write_all(be, (uint8_t *)buf, strlen(buf));
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va_end(ap);
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}
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Chardev *qemu_chr_fe_get_driver(CharBackend *be)
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{
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/* this is unsafe for the users that support chardev hotswap */
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assert(be->chr_be_change == NULL);
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return be->chr;
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}
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bool qemu_chr_fe_backend_connected(CharBackend *be)
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{
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return !!be->chr;
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}
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bool qemu_chr_fe_backend_open(CharBackend *be)
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{
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return be->chr && be->chr->be_open;
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}
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bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp)
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{
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int tag = 0;
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if (s) {
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if (CHARDEV_IS_MUX(s)) {
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MuxChardev *d = MUX_CHARDEV(s);
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if (d->mux_cnt >= MAX_MUX) {
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goto unavailable;
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}
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d->backends[d->mux_cnt] = b;
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tag = d->mux_cnt++;
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} else if (s->be) {
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goto unavailable;
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} else {
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s->be = b;
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}
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}
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b->fe_open = false;
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b->tag = tag;
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b->chr = s;
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return true;
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unavailable:
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error_setg(errp, QERR_DEVICE_IN_USE, s->label);
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return false;
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}
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void qemu_chr_fe_deinit(CharBackend *b, bool del)
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{
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assert(b);
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if (b->chr) {
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qemu_chr_fe_set_handlers(b, NULL, NULL, NULL, NULL, NULL, NULL, true);
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if (b->chr->be == b) {
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b->chr->be = NULL;
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}
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if (CHARDEV_IS_MUX(b->chr)) {
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MuxChardev *d = MUX_CHARDEV(b->chr);
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d->backends[b->tag] = NULL;
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}
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if (del) {
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Object *obj = OBJECT(b->chr);
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if (obj->parent) {
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object_unparent(obj);
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} else {
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object_unref(obj);
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}
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}
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b->chr = NULL;
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}
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}
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void qemu_chr_fe_set_handlers_full(CharBackend *b,
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IOCanReadHandler *fd_can_read,
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IOReadHandler *fd_read,
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IOEventHandler *fd_event,
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BackendChangeHandler *be_change,
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void *opaque,
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GMainContext *context,
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bool set_open,
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bool sync_state)
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{
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Chardev *s;
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int fe_open;
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s = b->chr;
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if (!s) {
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return;
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}
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if (!opaque && !fd_can_read && !fd_read && !fd_event) {
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fe_open = 0;
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remove_fd_in_watch(s);
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} else {
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fe_open = 1;
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}
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b->chr_can_read = fd_can_read;
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b->chr_read = fd_read;
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b->chr_event = fd_event;
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b->chr_be_change = be_change;
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b->opaque = opaque;
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qemu_chr_be_update_read_handlers(s, context);
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if (set_open) {
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qemu_chr_fe_set_open(b, fe_open);
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}
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if (fe_open) {
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qemu_chr_fe_take_focus(b);
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/* We're connecting to an already opened device, so let's make sure we
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also get the open event */
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if (sync_state && s->be_open) {
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qemu_chr_be_event(s, CHR_EVENT_OPENED);
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}
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}
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if (CHARDEV_IS_MUX(s)) {
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mux_chr_set_handlers(s, context);
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}
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}
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void qemu_chr_fe_set_handlers(CharBackend *b,
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IOCanReadHandler *fd_can_read,
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IOReadHandler *fd_read,
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IOEventHandler *fd_event,
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BackendChangeHandler *be_change,
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void *opaque,
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GMainContext *context,
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bool set_open)
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{
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qemu_chr_fe_set_handlers_full(b, fd_can_read, fd_read, fd_event, be_change,
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opaque, context, set_open,
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true);
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}
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void qemu_chr_fe_take_focus(CharBackend *b)
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{
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if (!b->chr) {
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return;
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}
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if (CHARDEV_IS_MUX(b->chr)) {
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mux_set_focus(b->chr, b->tag);
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}
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}
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int qemu_chr_fe_wait_connected(CharBackend *be, Error **errp)
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{
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if (!be->chr) {
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error_setg(errp, "missing associated backend");
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return -1;
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}
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return qemu_chr_wait_connected(be->chr, errp);
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}
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void qemu_chr_fe_set_echo(CharBackend *be, bool echo)
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{
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Chardev *chr = be->chr;
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if (chr && CHARDEV_GET_CLASS(chr)->chr_set_echo) {
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CHARDEV_GET_CLASS(chr)->chr_set_echo(chr, echo);
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}
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}
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void qemu_chr_fe_set_open(CharBackend *be, int fe_open)
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{
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Chardev *chr = be->chr;
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if (!chr) {
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return;
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}
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if (be->fe_open == fe_open) {
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return;
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}
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be->fe_open = fe_open;
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if (CHARDEV_GET_CLASS(chr)->chr_set_fe_open) {
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CHARDEV_GET_CLASS(chr)->chr_set_fe_open(chr, fe_open);
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}
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}
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guint qemu_chr_fe_add_watch(CharBackend *be, GIOCondition cond,
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GIOFunc func, void *user_data)
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{
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Chardev *s = be->chr;
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GSource *src;
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guint tag;
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if (!s || CHARDEV_GET_CLASS(s)->chr_add_watch == NULL) {
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return 0;
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}
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src = CHARDEV_GET_CLASS(s)->chr_add_watch(s, cond);
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if (!src) {
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return 0;
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}
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g_source_set_callback(src, (GSourceFunc)func, user_data, NULL);
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tag = g_source_attach(src, s->gcontext);
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g_source_unref(src);
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return tag;
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}
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void qemu_chr_fe_disconnect(CharBackend *be)
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{
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Chardev *chr = be->chr;
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if (chr && CHARDEV_GET_CLASS(chr)->chr_disconnect) {
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CHARDEV_GET_CLASS(chr)->chr_disconnect(chr);
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}
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}
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