qemu/chardev/char-parallel.c
Markus Armbruster a58c439a2d chardev/parallel: Don't close stdin on inappropriate device
The __linux__ version of qemu_chr_open_pp_fd() tries to claim the
parport device with a PPCLAIM ioctl().  On success, it stores the file
descriptor in the chardev object, and returns success.  On failure, it
closes the file descriptor, and returns failure.

chardev_new() then passes the Chardev to object_unref().  This duly
calls char_parallel_finalize(), which closes the file descriptor
stored in the chardev object.  Since qemu_chr_open_pp_fd() didn't
store it, it's still zero, so this closes standard input.  Ooopsie.

To demonstate, add a unit test.  With the bug above unfixed, running
this test closes standard input.  char_hotswap_test() happens to run
next.  It opens a socket, duly gets file descriptor 0, and since it
tests for success with > 0 instead of >= 0, it fails.

The new unit test needs to be conditional exactly like the chardev it
tests.  Since the condition is rather complicated, steal the solution
from the serial chardev: define HAVE_CHARDEV_PARALLEL in qemu/osdep.h.
This also permits simplifying chardev/meson.build a bit.

The bug fix is easy enough: store the file descriptor, and leave
closing it to char_parallel_finalize().

The next commit will fix char_hotswap_test()'s test for success.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240203080228.2766159-2-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[Test fixed up for BSDs, indentation fixed up, commit message improved]
2024-02-14 07:44:38 +01:00

312 lines
8.5 KiB
C

/*
* 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 "chardev/char.h"
#include "qapi/error.h"
#include "qemu/module.h"
#include "qemu/option.h"
#include <sys/ioctl.h>
#ifdef CONFIG_BSD
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
#include <dev/ppbus/ppi.h>
#include <dev/ppbus/ppbconf.h>
#elif defined(__DragonFly__)
#include <dev/misc/ppi/ppi.h>
#include <bus/ppbus/ppbconf.h>
#endif
#else
#ifdef __linux__
#include <linux/ppdev.h>
#include <linux/parport.h>
#endif
#endif
#include "chardev/char-fd.h"
#include "chardev/char-parallel.h"
#if defined(__linux__)
typedef struct {
Chardev parent;
int fd;
int mode;
} ParallelChardev;
#define PARALLEL_CHARDEV(obj) \
OBJECT_CHECK(ParallelChardev, (obj), TYPE_CHARDEV_PARALLEL)
static int pp_hw_mode(ParallelChardev *s, uint16_t mode)
{
if (s->mode != mode) {
int m = mode;
if (ioctl(s->fd, PPSETMODE, &m) < 0) {
return 0;
}
s->mode = mode;
}
return 1;
}
static int pp_ioctl(Chardev *chr, int cmd, void *arg)
{
ParallelChardev *drv = PARALLEL_CHARDEV(chr);
int fd = drv->fd;
uint8_t b;
switch (cmd) {
case CHR_IOCTL_PP_READ_DATA:
if (ioctl(fd, PPRDATA, &b) < 0) {
return -ENOTSUP;
}
*(uint8_t *)arg = b;
break;
case CHR_IOCTL_PP_WRITE_DATA:
b = *(uint8_t *)arg;
if (ioctl(fd, PPWDATA, &b) < 0) {
return -ENOTSUP;
}
break;
case CHR_IOCTL_PP_READ_CONTROL:
if (ioctl(fd, PPRCONTROL, &b) < 0) {
return -ENOTSUP;
}
/* Linux gives only the lowest bits, and no way to know data
direction! For better compatibility set the fixed upper
bits. */
*(uint8_t *)arg = b | 0xc0;
break;
case CHR_IOCTL_PP_WRITE_CONTROL:
b = *(uint8_t *)arg;
if (ioctl(fd, PPWCONTROL, &b) < 0) {
return -ENOTSUP;
}
break;
case CHR_IOCTL_PP_READ_STATUS:
if (ioctl(fd, PPRSTATUS, &b) < 0) {
return -ENOTSUP;
}
*(uint8_t *)arg = b;
break;
case CHR_IOCTL_PP_DATA_DIR:
if (ioctl(fd, PPDATADIR, (int *)arg) < 0) {
return -ENOTSUP;
}
break;
case CHR_IOCTL_PP_EPP_READ_ADDR:
if (pp_hw_mode(drv, IEEE1284_MODE_EPP | IEEE1284_ADDR)) {
struct ParallelIOArg *parg = arg;
int n = read(fd, parg->buffer, parg->count);
if (n != parg->count) {
return -EIO;
}
}
break;
case CHR_IOCTL_PP_EPP_READ:
if (pp_hw_mode(drv, IEEE1284_MODE_EPP)) {
struct ParallelIOArg *parg = arg;
int n = read(fd, parg->buffer, parg->count);
if (n != parg->count) {
return -EIO;
}
}
break;
case CHR_IOCTL_PP_EPP_WRITE_ADDR:
if (pp_hw_mode(drv, IEEE1284_MODE_EPP | IEEE1284_ADDR)) {
struct ParallelIOArg *parg = arg;
int n = write(fd, parg->buffer, parg->count);
if (n != parg->count) {
return -EIO;
}
}
break;
case CHR_IOCTL_PP_EPP_WRITE:
if (pp_hw_mode(drv, IEEE1284_MODE_EPP)) {
struct ParallelIOArg *parg = arg;
int n = write(fd, parg->buffer, parg->count);
if (n != parg->count) {
return -EIO;
}
}
break;
default:
return -ENOTSUP;
}
return 0;
}
static void qemu_chr_open_pp_fd(Chardev *chr,
int fd,
bool *be_opened,
Error **errp)
{
ParallelChardev *drv = PARALLEL_CHARDEV(chr);
drv->fd = fd;
if (ioctl(fd, PPCLAIM) < 0) {
error_setg_errno(errp, errno, "not a parallel port");
return;
}
drv->mode = IEEE1284_MODE_COMPAT;
}
#endif /* __linux__ */
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
typedef struct {
Chardev parent;
int fd;
} ParallelChardev;
#define PARALLEL_CHARDEV(obj) \
OBJECT_CHECK(ParallelChardev, (obj), TYPE_CHARDEV_PARALLEL)
static int pp_ioctl(Chardev *chr, int cmd, void *arg)
{
ParallelChardev *drv = PARALLEL_CHARDEV(chr);
uint8_t b;
switch (cmd) {
case CHR_IOCTL_PP_READ_DATA:
if (ioctl(drv->fd, PPIGDATA, &b) < 0) {
return -ENOTSUP;
}
*(uint8_t *)arg = b;
break;
case CHR_IOCTL_PP_WRITE_DATA:
b = *(uint8_t *)arg;
if (ioctl(drv->fd, PPISDATA, &b) < 0) {
return -ENOTSUP;
}
break;
case CHR_IOCTL_PP_READ_CONTROL:
if (ioctl(drv->fd, PPIGCTRL, &b) < 0) {
return -ENOTSUP;
}
*(uint8_t *)arg = b;
break;
case CHR_IOCTL_PP_WRITE_CONTROL:
b = *(uint8_t *)arg;
if (ioctl(drv->fd, PPISCTRL, &b) < 0) {
return -ENOTSUP;
}
break;
case CHR_IOCTL_PP_READ_STATUS:
if (ioctl(drv->fd, PPIGSTATUS, &b) < 0) {
return -ENOTSUP;
}
*(uint8_t *)arg = b;
break;
default:
return -ENOTSUP;
}
return 0;
}
static void qemu_chr_open_pp_fd(Chardev *chr,
int fd,
bool *be_opened,
Error **errp)
{
ParallelChardev *drv = PARALLEL_CHARDEV(chr);
drv->fd = fd;
*be_opened = false;
}
#endif
#ifdef HAVE_CHARDEV_PARALLEL
static void qmp_chardev_open_parallel(Chardev *chr,
ChardevBackend *backend,
bool *be_opened,
Error **errp)
{
ChardevHostdev *parallel = backend->u.parallel.data;
int fd;
fd = qmp_chardev_open_file_source(parallel->device, O_RDWR, errp);
if (fd < 0) {
return;
}
qemu_chr_open_pp_fd(chr, fd, be_opened, errp);
}
static void qemu_chr_parse_parallel(QemuOpts *opts, ChardevBackend *backend,
Error **errp)
{
const char *device = qemu_opt_get(opts, "path");
ChardevHostdev *parallel;
if (device == NULL) {
error_setg(errp, "chardev: parallel: no device path given");
return;
}
backend->type = CHARDEV_BACKEND_KIND_PARALLEL;
parallel = backend->u.parallel.data = g_new0(ChardevHostdev, 1);
qemu_chr_parse_common(opts, qapi_ChardevHostdev_base(parallel));
parallel->device = g_strdup(device);
}
static void char_parallel_class_init(ObjectClass *oc, void *data)
{
ChardevClass *cc = CHARDEV_CLASS(oc);
cc->parse = qemu_chr_parse_parallel;
cc->open = qmp_chardev_open_parallel;
cc->chr_ioctl = pp_ioctl;
}
static void char_parallel_finalize(Object *obj)
{
Chardev *chr = CHARDEV(obj);
ParallelChardev *drv = PARALLEL_CHARDEV(chr);
int fd = drv->fd;
#if defined(__linux__)
pp_hw_mode(drv, IEEE1284_MODE_COMPAT);
ioctl(fd, PPRELEASE);
#endif
close(fd);
qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
}
static const TypeInfo char_parallel_type_info = {
.name = TYPE_CHARDEV_PARALLEL,
.parent = TYPE_CHARDEV,
.instance_size = sizeof(ParallelChardev),
.instance_finalize = char_parallel_finalize,
.class_init = char_parallel_class_init,
};
static void register_types(void)
{
type_register_static(&char_parallel_type_info);
}
type_init(register_types);
#endif /* HAVE_CHARDEV_PARALLEL */