qemu/hw/char/terminal3270.c
Pierre Morel d895d25ae2 s390x: css: report errors from ccw_dstream_read/write
ccw_dstream_read/write functions returned values are sometime
not taking into account and reported back to the upper level
of interpretation of CCW instructions.

It follows that accessing an invalid address does not trigger
a subchannel status program check to the guest as it should.

Let's test the return values of ccw_dstream_write[_buf] and
ccw_dstream_read[_buf] and report it to the caller.

Cc: qemu-stable@nongnu.org
Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Message-Id: <1617899529-9329-2-git-send-email-pmorel@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
2021-04-09 10:52:13 +02:00

322 lines
8.7 KiB
C

/*
* Terminal 3270 implementation
*
* Copyright 2017 IBM Corp.
*
* Authors: Yang Chen <bjcyang@linux.vnet.ibm.com>
* Jing Liu <liujbjl@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or (at
* your option) any later version. See the COPYING file in the top-level
* directory.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/module.h"
#include "chardev/char-fe.h"
#include "hw/qdev-properties.h"
#include "hw/qdev-properties-system.h"
#include "hw/s390x/3270-ccw.h"
#include "qom/object.h"
/* Enough spaces for different window sizes. */
#define INPUT_BUFFER_SIZE 1000
/*
* 1 for header, 1024*2 for datastream, 2 for tail
* Reserve enough spaces for telnet IAC escape.
*/
#define OUTPUT_BUFFER_SIZE 2051
struct Terminal3270 {
EmulatedCcw3270Device cdev;
CharBackend chr;
uint8_t inv[INPUT_BUFFER_SIZE];
uint8_t outv[OUTPUT_BUFFER_SIZE];
int in_len;
bool handshake_done;
guint timer_tag;
};
typedef struct Terminal3270 Terminal3270;
#define TYPE_TERMINAL_3270 "x-terminal3270"
DECLARE_INSTANCE_CHECKER(Terminal3270, TERMINAL_3270,
TYPE_TERMINAL_3270)
static int terminal_can_read(void *opaque)
{
Terminal3270 *t = opaque;
return INPUT_BUFFER_SIZE - t->in_len;
}
static void terminal_timer_cancel(Terminal3270 *t)
{
if (t->timer_tag) {
g_source_remove(t->timer_tag);
t->timer_tag = 0;
}
}
/*
* Protocol handshake done,
* signal guest by an unsolicited DE irq.
*/
static void TN3270_handshake_done(Terminal3270 *t)
{
CcwDevice *ccw_dev = CCW_DEVICE(t);
SubchDev *sch = ccw_dev->sch;
t->handshake_done = true;
sch->curr_status.scsw.dstat = SCSW_DSTAT_DEVICE_END;
css_conditional_io_interrupt(sch);
}
/*
* Called when the interval is timeout to detect
* if the client is still alive by Timing Mark.
*/
static gboolean send_timing_mark_cb(gpointer opaque)
{
Terminal3270 *t = opaque;
const uint8_t timing[] = {0xff, 0xfd, 0x06};
qemu_chr_fe_write_all(&t->chr, timing, sizeof(timing));
return true;
}
/*
* Receive inbound data from socket.
* For data given to guest, drop the data boundary IAC, IAC_EOR.
* TODO:
* Using "Reset" key on x3270 may result multiple commands in one packet.
* This usually happens when the user meets a poor traffic of the network.
* As of now, for such case, we simply terminate the connection,
* and we should come back here later with a better solution.
*/
static void terminal_read(void *opaque, const uint8_t *buf, int size)
{
Terminal3270 *t = opaque;
CcwDevice *ccw_dev = CCW_DEVICE(t);
SubchDev *sch = ccw_dev->sch;
int end;
assert(size <= (INPUT_BUFFER_SIZE - t->in_len));
terminal_timer_cancel(t);
t->timer_tag = g_timeout_add_seconds(600, send_timing_mark_cb, t);
memcpy(&t->inv[t->in_len], buf, size);
t->in_len += size;
if (t->in_len < 2) {
return;
}
if (!t->handshake_done) {
/*
* Receiving Terminal Type is the last step of handshake.
* The data format: IAC SB Terminal-Type IS <terminal type> IAC SE
* The code for Terminal-Type is 0x18, for IS is 0.
* Simply check the data format and mark handshake_done.
*/
if (t->in_len > 6 && t->inv[2] == 0x18 && t->inv[3] == 0x0 &&
t->inv[t->in_len - 2] == IAC && t->inv[t->in_len - 1] == IAC_SE) {
TN3270_handshake_done(t);
t->in_len = 0;
}
return;
}
for (end = 0; end < t->in_len - 1; end++) {
if (t->inv[end] == IAC && t->inv[end + 1] == IAC_EOR) {
break;
}
}
if (end == t->in_len - 2) {
/* Data is valid for consuming. */
t->in_len -= 2;
sch->curr_status.scsw.dstat = SCSW_DSTAT_ATTENTION;
css_conditional_io_interrupt(sch);
} else if (end < t->in_len - 2) {
/* "Reset" key is used. */
qemu_chr_fe_disconnect(&t->chr);
} else {
/* Gathering data. */
return;
}
}
static void chr_event(void *opaque, QEMUChrEvent event)
{
Terminal3270 *t = opaque;
CcwDevice *ccw_dev = CCW_DEVICE(t);
SubchDev *sch = ccw_dev->sch;
/* Ensure the initial status correct, always reset them. */
t->in_len = 0;
t->handshake_done = false;
terminal_timer_cancel(t);
switch (event) {
case CHR_EVENT_OPENED:
/*
* 3270 does handshake firstly by the negotiate options in
* char-socket.c. Once qemu receives the terminal-type of the
* client, mark handshake done and trigger everything rolling again.
*/
t->timer_tag = g_timeout_add_seconds(600, send_timing_mark_cb, t);
break;
case CHR_EVENT_CLOSED:
sch->curr_status.scsw.dstat = SCSW_DSTAT_DEVICE_END;
css_conditional_io_interrupt(sch);
break;
case CHR_EVENT_BREAK:
case CHR_EVENT_MUX_IN:
case CHR_EVENT_MUX_OUT:
/* Ignore */
break;
}
}
static void terminal_init(EmulatedCcw3270Device *dev, Error **errp)
{
Terminal3270 *t = TERMINAL_3270(dev);
static bool terminal_available;
if (terminal_available) {
error_setg(errp, "Multiple 3270 terminals are not supported.");
return;
}
terminal_available = true;
qemu_chr_fe_set_handlers(&t->chr, terminal_can_read,
terminal_read, chr_event, NULL, t, NULL, true);
}
static inline CcwDataStream *get_cds(Terminal3270 *t)
{
return &(CCW_DEVICE(&t->cdev)->sch->cds);
}
static int read_payload_3270(EmulatedCcw3270Device *dev)
{
Terminal3270 *t = TERMINAL_3270(dev);
int len;
int ret;
len = MIN(ccw_dstream_avail(get_cds(t)), t->in_len);
ret = ccw_dstream_write_buf(get_cds(t), t->inv, len);
if (ret < 0) {
return ret;
}
t->in_len -= len;
return len;
}
/* TN3270 uses binary transmission, which needs escape IAC to IAC IAC */
static int insert_IAC_escape_char(uint8_t *outv, int out_len)
{
int IAC_num = 0, new_out_len, i, j;
for (i = 0; i < out_len; i++) {
if (outv[i] == IAC) {
IAC_num++;
}
}
if (IAC_num == 0) {
return out_len;
}
new_out_len = out_len + IAC_num;
for (i = out_len - 1, j = new_out_len - 1; j > i && i >= 0; i--, j--) {
outv[j] = outv[i];
if (outv[i] == IAC) {
outv[--j] = IAC;
}
}
return new_out_len;
}
/*
* Write 3270 outbound to socket.
* Return the count of 3270 data field if succeeded, zero if failed.
*/
static int write_payload_3270(EmulatedCcw3270Device *dev, uint8_t cmd)
{
Terminal3270 *t = TERMINAL_3270(dev);
int retval = 0;
int count = ccw_dstream_avail(get_cds(t));
int bound = (OUTPUT_BUFFER_SIZE - 3) / 2;
int len = MIN(count, bound);
int out_len = 0;
if (!t->handshake_done) {
if (!(t->outv[0] == IAC && t->outv[1] != IAC)) {
/*
* Before having finished 3270 negotiation,
* sending outbound data except protocol options is prohibited.
*/
return 0;
}
}
if (!qemu_chr_fe_backend_connected(&t->chr)) {
/* We just say we consumed all data if there's no backend. */
return count;
}
t->outv[out_len++] = cmd;
do {
retval = ccw_dstream_read_buf(get_cds(t), &t->outv[out_len], len);
if (retval < 0) {
return retval;
}
count = ccw_dstream_avail(get_cds(t));
out_len += len;
out_len = insert_IAC_escape_char(t->outv, out_len);
if (!count) {
t->outv[out_len++] = IAC;
t->outv[out_len++] = IAC_EOR;
}
retval = qemu_chr_fe_write_all(&t->chr, t->outv, out_len);
len = MIN(count, bound);
out_len = 0;
} while (len && retval >= 0);
return (retval <= 0) ? 0 : get_cds(t)->count;
}
static Property terminal_properties[] = {
DEFINE_PROP_CHR("chardev", Terminal3270, chr),
DEFINE_PROP_END_OF_LIST(),
};
static const VMStateDescription terminal3270_vmstate = {
.name = TYPE_TERMINAL_3270,
.unmigratable = 1,
};
static void terminal_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
EmulatedCcw3270Class *ck = EMULATED_CCW_3270_CLASS(klass);
device_class_set_props(dc, terminal_properties);
dc->vmsd = &terminal3270_vmstate;
ck->init = terminal_init;
ck->read_payload_3270 = read_payload_3270;
ck->write_payload_3270 = write_payload_3270;
}
static const TypeInfo ccw_terminal_info = {
.name = TYPE_TERMINAL_3270,
.parent = TYPE_EMULATED_CCW_3270,
.instance_size = sizeof(Terminal3270),
.class_init = terminal_class_init,
.class_size = sizeof(EmulatedCcw3270Class),
};
static void register_types(void)
{
type_register_static(&ccw_terminal_info);
}
type_init(register_types)