qemu-e2k/hw/char/sclpconsole.c

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/*
* SCLP event type
* Ascii Console Data (VT220 Console)
*
* Copyright IBM, Corp. 2012
*
* Authors:
* Heinz Graalfs <graalfs@de.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 "qemu/thread.h"
#include "qemu/error-report.h"
#include "qemu/module.h"
#include "hw/s390x/sclp.h"
#include "migration/vmstate.h"
#include "hw/qdev-properties.h"
#include "hw/s390x/event-facility.h"
#include "chardev/char-fe.h"
#include "qom/object.h"
typedef struct ASCIIConsoleData {
EventBufferHeader ebh;
misc: Replace zero-length arrays with flexible array member (manual) Description copied from Linux kernel commit from Gustavo A. R. Silva (see [3]): --v-- description start --v-- The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member [1], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being unadvertenly introduced [2] to the Linux codebase from now on. --^-- description end --^-- Do the similar housekeeping in the QEMU codebase (which uses C99 since commit 7be41675f7cb). All these instances of code were found with the help of the following command (then manual analysis, without modifying structures only having a single flexible array member, such QEDTable in block/qed.h): git grep -F '[0];' [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=76497732932f [3] https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/commit/?id=17642a2fbd2c1 Inspired-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-04 16:38:16 +01:00
char data[];
} QEMU_PACKED ASCIIConsoleData;
/* max size for ASCII data in 4K SCCB page */
#define SIZE_BUFFER_VT220 4080
struct SCLPConsole {
SCLPEvent event;
CharBackend chr;
uint8_t iov[SIZE_BUFFER_VT220];
uint32_t iov_sclp; /* offset in buf for SCLP read operation */
uint32_t iov_bs; /* offset in buf for char layer read operation */
uint32_t iov_data_len; /* length of byte stream in buffer */
uint32_t iov_sclp_rest; /* length of byte stream not read via SCLP */
bool notify; /* qemu_notify_event() req'd if true */
};
typedef struct SCLPConsole SCLPConsole;
#define TYPE_SCLP_CONSOLE "sclpconsole"
DECLARE_INSTANCE_CHECKER(SCLPConsole, SCLP_CONSOLE,
TYPE_SCLP_CONSOLE)
/* character layer call-back functions */
/* Return number of bytes that fit into iov buffer */
static int chr_can_read(void *opaque)
{
SCLPConsole *scon = opaque;
int avail = SIZE_BUFFER_VT220 - scon->iov_data_len;
if (avail == 0) {
scon->notify = true;
}
return avail;
}
/* Send data from a char device over to the guest */
static void chr_read(void *opaque, const uint8_t *buf, int size)
{
SCLPConsole *scon = opaque;
assert(scon);
/* read data must fit into current buffer */
assert(size <= SIZE_BUFFER_VT220 - scon->iov_data_len);
/* put byte-stream from character layer into buffer */
memcpy(&scon->iov[scon->iov_bs], buf, size);
scon->iov_data_len += size;
scon->iov_sclp_rest += size;
scon->iov_bs += size;
scon->event.event_pending = true;
sclp_service_interrupt(0);
}
/* functions to be called by event facility */
static bool can_handle_event(uint8_t type)
{
return type == SCLP_EVENT_ASCII_CONSOLE_DATA;
}
static sccb_mask_t send_mask(void)
{
return SCLP_EVENT_MASK_MSG_ASCII;
}
static sccb_mask_t receive_mask(void)
{
return SCLP_EVENT_MASK_MSG_ASCII;
}
/* triggered by SCLP's read_event_data -
* copy console data byte-stream into provided (SCLP) buffer
*/
static void get_console_data(SCLPEvent *event, uint8_t *buf, size_t *size,
int avail)
{
SCLPConsole *cons = SCLP_CONSOLE(event);
/* first byte is hex 0 saying an ascii string follows */
*buf++ = '\0';
avail--;
/* if all data fit into provided SCLP buffer */
if (avail >= cons->iov_sclp_rest) {
/* copy character byte-stream to SCLP buffer */
memcpy(buf, &cons->iov[cons->iov_sclp], cons->iov_sclp_rest);
*size = cons->iov_sclp_rest + 1;
cons->iov_sclp = 0;
cons->iov_bs = 0;
cons->iov_data_len = 0;
cons->iov_sclp_rest = 0;
event->event_pending = false;
/* data provided and no more data pending */
} else {
/* if provided buffer is too small, just copy part */
memcpy(buf, &cons->iov[cons->iov_sclp], avail);
*size = avail + 1;
cons->iov_sclp_rest -= avail;
cons->iov_sclp += avail;
/* more data pending */
}
if (cons->notify) {
cons->notify = false;
qemu_notify_event();
}
}
static int read_event_data(SCLPEvent *event, EventBufferHeader *evt_buf_hdr,
int *slen)
{
int avail;
size_t src_len;
uint8_t *to;
ASCIIConsoleData *acd = (ASCIIConsoleData *) evt_buf_hdr;
if (!event->event_pending) {
/* no data pending */
return 0;
}
to = (uint8_t *)&acd->data;
avail = *slen - sizeof(ASCIIConsoleData);
get_console_data(event, to, &src_len, avail);
acd->ebh.length = cpu_to_be16(sizeof(ASCIIConsoleData) + src_len);
acd->ebh.type = SCLP_EVENT_ASCII_CONSOLE_DATA;
acd->ebh.flags |= SCLP_EVENT_BUFFER_ACCEPTED;
*slen = avail - src_len;
return 1;
}
/* triggered by SCLP's write_event_data
* - write console data to character layer
* returns < 0 if an error occurred
*/
static ssize_t write_console_data(SCLPEvent *event, const uint8_t *buf,
size_t len)
{
SCLPConsole *scon = SCLP_CONSOLE(event);
if (!qemu_chr_fe_backend_connected(&scon->chr)) {
/* If there's no backend, we can just say we consumed all data. */
return len;
}
/* XXX this blocks entire thread. Rewrite to use
* qemu_chr_fe_write and background I/O callbacks */
return qemu_chr_fe_write_all(&scon->chr, buf, len);
}
static int write_event_data(SCLPEvent *event, EventBufferHeader *evt_buf_hdr)
{
int rc;
int length;
ssize_t written;
ASCIIConsoleData *acd = (ASCIIConsoleData *) evt_buf_hdr;
length = be16_to_cpu(evt_buf_hdr->length) - sizeof(EventBufferHeader);
written = write_console_data(event, (uint8_t *)acd->data, length);
rc = SCLP_RC_NORMAL_COMPLETION;
/* set event buffer accepted flag */
evt_buf_hdr->flags |= SCLP_EVENT_BUFFER_ACCEPTED;
/* written will be zero if a pty is not connected - don't treat as error */
if (written < 0) {
/* event buffer not accepted due to error in character layer */
evt_buf_hdr->flags &= ~(SCLP_EVENT_BUFFER_ACCEPTED);
rc = SCLP_RC_CONTAINED_EQUIPMENT_CHECK;
}
return rc;
}
static const VMStateDescription vmstate_sclpconsole = {
.name = "sclpconsole",
.version_id = 0,
.minimum_version_id = 0,
.fields = (VMStateField[]) {
VMSTATE_BOOL(event.event_pending, SCLPConsole),
VMSTATE_UINT8_ARRAY(iov, SCLPConsole, SIZE_BUFFER_VT220),
VMSTATE_UINT32(iov_sclp, SCLPConsole),
VMSTATE_UINT32(iov_bs, SCLPConsole),
VMSTATE_UINT32(iov_data_len, SCLPConsole),
VMSTATE_UINT32(iov_sclp_rest, SCLPConsole),
VMSTATE_END_OF_LIST()
}
};
/* qemu object creation and initialization functions */
/* tell character layer our call-back functions */
static int console_init(SCLPEvent *event)
{
static bool console_available;
SCLPConsole *scon = SCLP_CONSOLE(event);
if (console_available) {
error_report("Multiple VT220 operator consoles are not supported");
return -1;
}
console_available = true;
qemu_chr_fe_set_handlers(&scon->chr, chr_can_read,
chr_read, NULL, NULL, scon, NULL, true);
return 0;
}
static void console_reset(DeviceState *dev)
{
SCLPEvent *event = SCLP_EVENT(dev);
SCLPConsole *scon = SCLP_CONSOLE(event);
event->event_pending = false;
scon->iov_sclp = 0;
scon->iov_bs = 0;
scon->iov_data_len = 0;
scon->iov_sclp_rest = 0;
scon->notify = false;
}
static Property console_properties[] = {
DEFINE_PROP_CHR("chardev", SCLPConsole, chr),
DEFINE_PROP_END_OF_LIST(),
};
static void console_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
SCLPEventClass *ec = SCLP_EVENT_CLASS(klass);
device_class_set_props(dc, console_properties);
dc->reset = console_reset;
dc->vmsd = &vmstate_sclpconsole;
ec->init = console_init;
ec->get_send_mask = send_mask;
ec->get_receive_mask = receive_mask;
ec->can_handle_event = can_handle_event;
ec->read_event_data = read_event_data;
ec->write_event_data = write_event_data;
set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
}
static const TypeInfo sclp_console_info = {
.name = TYPE_SCLP_CONSOLE,
.parent = TYPE_SCLP_EVENT,
.instance_size = sizeof(SCLPConsole),
.class_init = console_class_init,
.class_size = sizeof(SCLPEventClass),
};
static void register_types(void)
{
type_register_static(&sclp_console_info);
}
type_init(register_types)