qemu/chardev/char-mux.c

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/*
* QEMU System Emulator
*
* 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 "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/option.h"
#include "chardev/char.h"
#include "sysemu/block-backend.h"
#include "sysemu/sysemu.h"
#include "chardev/char-mux.h"
/* MUX driver for serial I/O splitting */
/* Called with chr_write_lock held. */
static int mux_chr_write(Chardev *chr, const uint8_t *buf, int len)
{
MuxChardev *d = MUX_CHARDEV(chr);
int ret;
if (!d->timestamps) {
ret = qemu_chr_fe_write(&d->chr, buf, len);
} else {
int i;
ret = 0;
for (i = 0; i < len; i++) {
if (d->linestart) {
char buf1[64];
int64_t ti;
int secs;
ti = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
if (d->timestamps_start == -1) {
d->timestamps_start = ti;
}
ti -= d->timestamps_start;
secs = ti / 1000;
snprintf(buf1, sizeof(buf1),
"[%02d:%02d:%02d.%03d] ",
secs / 3600,
(secs / 60) % 60,
secs % 60,
(int)(ti % 1000));
/* XXX this blocks entire thread. Rewrite to use
* qemu_chr_fe_write and background I/O callbacks */
qemu_chr_fe_write_all(&d->chr,
(uint8_t *)buf1, strlen(buf1));
d->linestart = 0;
}
ret += qemu_chr_fe_write(&d->chr, buf + i, 1);
if (buf[i] == '\n') {
d->linestart = 1;
}
}
}
return ret;
}
static const char * const mux_help[] = {
"% h print this help\n\r",
"% x exit emulator\n\r",
"% s save disk data back to file (if -snapshot)\n\r",
"% t toggle console timestamps\n\r",
"% b send break (magic sysrq)\n\r",
"% c switch between console and monitor\n\r",
"% % sends %\n\r",
NULL
};
int term_escape_char = 0x01; /* ctrl-a is used for escape */
static void mux_print_help(Chardev *chr)
{
int i, j;
char ebuf[15] = "Escape-Char";
char cbuf[50] = "\n\r";
if (term_escape_char > 0 && term_escape_char < 26) {
snprintf(cbuf, sizeof(cbuf), "\n\r");
snprintf(ebuf, sizeof(ebuf), "C-%c", term_escape_char - 1 + 'a');
} else {
snprintf(cbuf, sizeof(cbuf),
"\n\rEscape-Char set to Ascii: 0x%02x\n\r\n\r",
term_escape_char);
}
/* XXX this blocks entire thread. Rewrite to use
* qemu_chr_fe_write and background I/O callbacks */
qemu_chr_write_all(chr, (uint8_t *)cbuf, strlen(cbuf));
for (i = 0; mux_help[i] != NULL; i++) {
for (j = 0; mux_help[i][j] != '\0'; j++) {
if (mux_help[i][j] == '%') {
qemu_chr_write_all(chr, (uint8_t *)ebuf, strlen(ebuf));
} else {
qemu_chr_write_all(chr, (uint8_t *)&mux_help[i][j], 1);
}
}
}
}
static void mux_chr_send_event(MuxChardev *d, int mux_nr, int event)
{
CharBackend *be = d->backends[mux_nr];
if (be && be->chr_event) {
be->chr_event(be->opaque, event);
}
}
static void mux_chr_be_event(Chardev *chr, int event)
{
MuxChardev *d = MUX_CHARDEV(chr);
if (d->focus != -1) {
mux_chr_send_event(d, d->focus, event);
}
}
static int mux_proc_byte(Chardev *chr, MuxChardev *d, int ch)
{
if (d->term_got_escape) {
d->term_got_escape = 0;
if (ch == term_escape_char) {
goto send_char;
}
switch (ch) {
case '?':
case 'h':
mux_print_help(chr);
break;
case 'x':
{
const char *term = "QEMU: Terminated\n\r";
qemu_chr_write_all(chr, (uint8_t *)term, strlen(term));
exit(0);
break;
}
case 's':
blk_commit_all();
break;
case 'b':
qemu_chr_be_event(chr, CHR_EVENT_BREAK);
break;
case 'c':
assert(d->mux_cnt > 0); /* handler registered with first fe */
/* Switch to the next registered device */
mux_set_focus(chr, (d->focus + 1) % d->mux_cnt);
break;
case 't':
d->timestamps = !d->timestamps;
d->timestamps_start = -1;
d->linestart = 0;
break;
}
} else if (ch == term_escape_char) {
d->term_got_escape = 1;
} else {
send_char:
return 1;
}
return 0;
}
static void mux_chr_accept_input(Chardev *chr)
{
MuxChardev *d = MUX_CHARDEV(chr);
int m = d->focus;
CharBackend *be = d->backends[m];
while (be && d->prod[m] != d->cons[m] &&
be->chr_can_read && be->chr_can_read(be->opaque)) {
be->chr_read(be->opaque,
&d->buffer[m][d->cons[m]++ & MUX_BUFFER_MASK], 1);
}
}
static int mux_chr_can_read(void *opaque)
{
MuxChardev *d = MUX_CHARDEV(opaque);
int m = d->focus;
CharBackend *be = d->backends[m];
if ((d->prod[m] - d->cons[m]) < MUX_BUFFER_SIZE) {
return 1;
}
if (be && be->chr_can_read) {
return be->chr_can_read(be->opaque);
}
return 0;
}
static void mux_chr_read(void *opaque, const uint8_t *buf, int size)
{
Chardev *chr = CHARDEV(opaque);
MuxChardev *d = MUX_CHARDEV(opaque);
int m = d->focus;
CharBackend *be = d->backends[m];
int i;
mux_chr_accept_input(opaque);
for (i = 0; i < size; i++)
if (mux_proc_byte(chr, d, buf[i])) {
if (d->prod[m] == d->cons[m] &&
be && be->chr_can_read &&
be->chr_can_read(be->opaque)) {
be->chr_read(be->opaque, &buf[i], 1);
} else {
d->buffer[m][d->prod[m]++ & MUX_BUFFER_MASK] = buf[i];
}
}
}
void mux_chr_send_all_event(Chardev *chr, int event)
{
MuxChardev *d = MUX_CHARDEV(chr);
int i;
if (!machine_init_done) {
return;
}
/* Send the event to all registered listeners */
for (i = 0; i < d->mux_cnt; i++) {
mux_chr_send_event(d, i, event);
}
}
static void mux_chr_event(void *opaque, int event)
{
mux_chr_send_all_event(CHARDEV(opaque), event);
}
static GSource *mux_chr_add_watch(Chardev *s, GIOCondition cond)
{
MuxChardev *d = MUX_CHARDEV(s);
Chardev *chr = qemu_chr_fe_get_driver(&d->chr);
ChardevClass *cc = CHARDEV_GET_CLASS(chr);
if (!cc->chr_add_watch) {
return NULL;
}
return cc->chr_add_watch(chr, cond);
}
static void char_mux_finalize(Object *obj)
{
MuxChardev *d = MUX_CHARDEV(obj);
int i;
for (i = 0; i < d->mux_cnt; i++) {
CharBackend *be = d->backends[i];
if (be) {
be->chr = NULL;
}
}
qemu_chr_fe_deinit(&d->chr, false);
}
static void mux_chr_update_read_handlers(Chardev *chr)
{
MuxChardev *d = MUX_CHARDEV(chr);
/* Fix up the real driver with mux routines */
chardev: fix mess in OPENED/CLOSED events when muxed 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>
2018-11-06 15:40:51 +03:00
qemu_chr_fe_set_handlers_full(&d->chr,
mux_chr_can_read,
mux_chr_read,
mux_chr_event,
NULL,
chr,
chr->gcontext, true, false);
}
void mux_set_focus(Chardev *chr, int focus)
{
MuxChardev *d = MUX_CHARDEV(chr);
assert(focus >= 0);
assert(focus < d->mux_cnt);
if (d->focus != -1) {
mux_chr_send_event(d, d->focus, CHR_EVENT_MUX_OUT);
}
d->focus = focus;
chr->be = d->backends[focus];
mux_chr_send_event(d, d->focus, CHR_EVENT_MUX_IN);
}
static void qemu_chr_open_mux(Chardev *chr,
ChardevBackend *backend,
bool *be_opened,
Error **errp)
{
ChardevMux *mux = backend->u.mux.data;
Chardev *drv;
MuxChardev *d = MUX_CHARDEV(chr);
drv = qemu_chr_find(mux->chardev);
if (drv == NULL) {
error_setg(errp, "mux: base chardev %s not found", mux->chardev);
return;
}
d->focus = -1;
/* only default to opened state if we've realized the initial
* set of muxes
*/
*be_opened = machine_init_done;
qemu_chr_fe_init(&d->chr, drv, errp);
}
static void qemu_chr_parse_mux(QemuOpts *opts, ChardevBackend *backend,
Error **errp)
{
const char *chardev = qemu_opt_get(opts, "chardev");
ChardevMux *mux;
if (chardev == NULL) {
error_setg(errp, "chardev: mux: no chardev given");
return;
}
backend->type = CHARDEV_BACKEND_KIND_MUX;
mux = backend->u.mux.data = g_new0(ChardevMux, 1);
qemu_chr_parse_common(opts, qapi_ChardevMux_base(mux));
mux->chardev = g_strdup(chardev);
}
/**
* Called after processing of default and command-line-specified
* chardevs to deliver CHR_EVENT_OPENED events to any FEs attached
* to a mux chardev. This is done here to ensure that
* output/prompts/banners are only displayed for the FE that has
* focus when initial command-line processing/machine init is
* completed.
*
* After this point, any new FE attached to any new or existing
* mux will receive CHR_EVENT_OPENED notifications for the BE
* immediately.
*/
static int open_muxes(Chardev *chr)
{
/* send OPENED to all already-attached FEs */
mux_chr_send_all_event(chr, CHR_EVENT_OPENED);
/*
* mark mux as OPENED so any new FEs will immediately receive
* OPENED event
*/
chardev: fix mess in OPENED/CLOSED events when muxed 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>
2018-11-06 15:40:51 +03:00
chr->be_open = 1;
return 0;
}
static void char_mux_class_init(ObjectClass *oc, void *data)
{
ChardevClass *cc = CHARDEV_CLASS(oc);
cc->parse = qemu_chr_parse_mux;
cc->open = qemu_chr_open_mux;
cc->chr_write = mux_chr_write;
cc->chr_accept_input = mux_chr_accept_input;
cc->chr_add_watch = mux_chr_add_watch;
cc->chr_be_event = mux_chr_be_event;
cc->chr_machine_done = open_muxes;
cc->chr_update_read_handler = mux_chr_update_read_handlers;
}
static const TypeInfo char_mux_type_info = {
.name = TYPE_CHARDEV_MUX,
.parent = TYPE_CHARDEV,
.class_init = char_mux_class_init,
.instance_size = sizeof(MuxChardev),
.instance_finalize = char_mux_finalize,
};
static void register_types(void)
{
type_register_static(&char_mux_type_info);
}
type_init(register_types);