qemu/include/chardev/char.h
Lukas Straub feb774ca3f chardev: Fix yank with the chardev-change case
When changing from chardev-socket (which supports yank) to
chardev-socket again, it fails, because the new chardev attempts
to register a new yank instance. This in turn fails, as there
still is the yank instance from the current chardev. Also,
the old chardev shouldn't unregister the yank instance when it
is freed.

To fix this, now the new chardev only registers a yank instance if
the current chardev doesn't support yank and thus hasn't registered
one already. Also, when the old chardev is freed, it now only
unregisters the yank instance if the new chardev doesn't need it.

If the initialization of the new chardev fails, it still has
chr->handover_yank_instance set and won't unregister the yank
instance when it is freed.

s->registered_yank is always true here, as chardev-change only works
on user-visible chardevs and those are guraranteed to register a
yank instance as they are initialized via
chardev_new()
 qemu_char_open()
  cc->open() (qmp_chardev_open_socket()).

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: Li Zhang <li.zhang@cloud.ionos.com>
Message-Id: <9637888d7591d2971975188478bb707299a1dc04.1617127849.git.lukasstraub2@web.de>
2021-04-01 15:27:44 +04:00

295 lines
9.4 KiB
C

#ifndef QEMU_CHAR_H
#define QEMU_CHAR_H
#include "qapi/qapi-types-char.h"
#include "qemu/bitmap.h"
#include "qemu/thread.h"
#include "qom/object.h"
#define IAC_EOR 239
#define IAC_SE 240
#define IAC_NOP 241
#define IAC_BREAK 243
#define IAC_IP 244
#define IAC_SB 250
#define IAC 255
/* character device */
typedef struct CharBackend CharBackend;
typedef enum {
CHR_EVENT_BREAK, /* serial break char */
CHR_EVENT_OPENED, /* new connection established */
CHR_EVENT_MUX_IN, /* mux-focus was set to this terminal */
CHR_EVENT_MUX_OUT, /* mux-focus will move on */
CHR_EVENT_CLOSED /* connection closed. NOTE: currently this event
* is only bound to the read port of the chardev.
* Normally the read port and write port of a
* chardev should be the same, but it can be
* different, e.g., for fd chardevs, when the two
* fds are different. So when we received the
* CLOSED event it's still possible that the out
* port is still open. TODO: we should only send
* the CLOSED event when both ports are closed.
*/
} QEMUChrEvent;
#define CHR_READ_BUF_LEN 4096
typedef enum {
/* Whether the chardev peer is able to close and
* reopen the data channel, thus requiring support
* for qemu_chr_wait_connected() to wait for a
* valid connection */
QEMU_CHAR_FEATURE_RECONNECTABLE,
/* Whether it is possible to send/recv file descriptors
* over the data channel */
QEMU_CHAR_FEATURE_FD_PASS,
/* Whether replay or record mode is enabled */
QEMU_CHAR_FEATURE_REPLAY,
/* Whether the gcontext can be changed after calling
* qemu_chr_be_update_read_handlers() */
QEMU_CHAR_FEATURE_GCONTEXT,
QEMU_CHAR_FEATURE_LAST,
} ChardevFeature;
#define qemu_chr_replay(chr) qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_REPLAY)
struct Chardev {
Object parent_obj;
QemuMutex chr_write_lock;
CharBackend *be;
char *label;
char *filename;
int logfd;
int be_open;
/* used to coordinate the chardev-change special-case: */
bool handover_yank_instance;
GSource *gsource;
GMainContext *gcontext;
DECLARE_BITMAP(features, QEMU_CHAR_FEATURE_LAST);
};
/**
* qemu_chr_new_from_opts:
* @opts: see qemu-config.c for a list of valid options
* @context: the #GMainContext to be used at initialization time
*
* Create a new character backend from a QemuOpts list.
*
* Returns: on success: a new character backend
* otherwise: NULL; @errp specifies the error
* or left untouched in case of help option
*/
Chardev *qemu_chr_new_from_opts(QemuOpts *opts,
GMainContext *context,
Error **errp);
/**
* qemu_chr_parse_common:
* @opts: the options that still need parsing
* @backend: a new backend
*
* Parse the common options available to all character backends.
*/
void qemu_chr_parse_common(QemuOpts *opts, ChardevCommon *backend);
/**
* qemu_chr_parse_opts:
*
* Parse the options to the ChardevBackend struct.
*
* Returns: a new backend or NULL on error
*/
ChardevBackend *qemu_chr_parse_opts(QemuOpts *opts,
Error **errp);
/**
* qemu_chr_new:
* @label: the name of the backend
* @filename: the URI
* @context: the #GMainContext to be used at initialization time
*
* Create a new character backend from a URI.
* Do not implicitly initialize a monitor if the chardev is muxed.
*
* Returns: a new character backend
*/
Chardev *qemu_chr_new(const char *label, const char *filename,
GMainContext *context);
/**
* qemu_chr_new_mux_mon:
* @label: the name of the backend
* @filename: the URI
* @context: the #GMainContext to be used at initialization time
*
* Create a new character backend from a URI.
* Implicitly initialize a monitor if the chardev is muxed.
*
* Returns: a new character backend
*/
Chardev *qemu_chr_new_mux_mon(const char *label, const char *filename,
GMainContext *context);
/**
* qemu_chr_change:
* @opts: the new backend options
*
* Change an existing character backend
*/
void qemu_chr_change(QemuOpts *opts, Error **errp);
/**
* qemu_chr_cleanup:
*
* Delete all chardevs (when leaving qemu)
*/
void qemu_chr_cleanup(void);
/**
* qemu_chr_new_noreplay:
* @label: the name of the backend
* @filename: the URI
* @permit_mux_mon: if chardev is muxed, initialize a monitor
* @context: the #GMainContext to be used at initialization time
*
* Create a new character backend from a URI.
* Character device communications are not written
* into the replay log.
*
* Returns: a new character backend
*/
Chardev *qemu_chr_new_noreplay(const char *label, const char *filename,
bool permit_mux_mon, GMainContext *context);
/**
* qemu_chr_be_can_write:
*
* Determine how much data the front end can currently accept. This function
* returns the number of bytes the front end can accept. If it returns 0, the
* front end cannot receive data at the moment. The function must be polled
* to determine when data can be received.
*
* Returns: the number of bytes the front end can receive via @qemu_chr_be_write
*/
int qemu_chr_be_can_write(Chardev *s);
/**
* qemu_chr_be_write:
* @buf: a buffer to receive data from the front end
* @len: the number of bytes to receive from the front end
*
* Write data from the back end to the front end. Before issuing this call,
* the caller should call @qemu_chr_be_can_write to determine how much data
* the front end can currently accept.
*/
void qemu_chr_be_write(Chardev *s, uint8_t *buf, int len);
/**
* qemu_chr_be_write_impl:
* @buf: a buffer to receive data from the front end
* @len: the number of bytes to receive from the front end
*
* Implementation of back end writing. Used by replay module.
*/
void qemu_chr_be_write_impl(Chardev *s, uint8_t *buf, int len);
/**
* qemu_chr_be_update_read_handlers:
* @context: the gcontext that will be used to attach the watch sources
*
* Invoked when frontend read handlers are setup
*/
void qemu_chr_be_update_read_handlers(Chardev *s,
GMainContext *context);
/**
* qemu_chr_be_event:
* @event: the event to send
*
* Send an event from the back end to the front end.
*/
void qemu_chr_be_event(Chardev *s, QEMUChrEvent event);
int qemu_chr_add_client(Chardev *s, int fd);
Chardev *qemu_chr_find(const char *name);
bool qemu_chr_has_feature(Chardev *chr,
ChardevFeature feature);
void qemu_chr_set_feature(Chardev *chr,
ChardevFeature feature);
QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename,
bool permit_mux_mon);
int qemu_chr_write(Chardev *s, const uint8_t *buf, int len, bool write_all);
#define qemu_chr_write_all(s, buf, len) qemu_chr_write(s, buf, len, true)
int qemu_chr_wait_connected(Chardev *chr, Error **errp);
#define TYPE_CHARDEV "chardev"
OBJECT_DECLARE_TYPE(Chardev, ChardevClass, CHARDEV)
#define TYPE_CHARDEV_NULL "chardev-null"
#define TYPE_CHARDEV_MUX "chardev-mux"
#define TYPE_CHARDEV_RINGBUF "chardev-ringbuf"
#define TYPE_CHARDEV_PTY "chardev-pty"
#define TYPE_CHARDEV_CONSOLE "chardev-console"
#define TYPE_CHARDEV_STDIO "chardev-stdio"
#define TYPE_CHARDEV_PIPE "chardev-pipe"
#define TYPE_CHARDEV_MEMORY "chardev-memory"
#define TYPE_CHARDEV_PARALLEL "chardev-parallel"
#define TYPE_CHARDEV_FILE "chardev-file"
#define TYPE_CHARDEV_SERIAL "chardev-serial"
#define TYPE_CHARDEV_SOCKET "chardev-socket"
#define TYPE_CHARDEV_UDP "chardev-udp"
#define CHARDEV_IS_RINGBUF(chr) \
object_dynamic_cast(OBJECT(chr), TYPE_CHARDEV_RINGBUF)
#define CHARDEV_IS_PTY(chr) \
object_dynamic_cast(OBJECT(chr), TYPE_CHARDEV_PTY)
struct ChardevClass {
ObjectClass parent_class;
bool internal; /* TODO: eventually use TYPE_USER_CREATABLE */
bool supports_yank;
void (*parse)(QemuOpts *opts, ChardevBackend *backend, Error **errp);
void (*open)(Chardev *chr, ChardevBackend *backend,
bool *be_opened, Error **errp);
int (*chr_write)(Chardev *s, const uint8_t *buf, int len);
int (*chr_sync_read)(Chardev *s, const uint8_t *buf, int len);
GSource *(*chr_add_watch)(Chardev *s, GIOCondition cond);
void (*chr_update_read_handler)(Chardev *s);
int (*chr_ioctl)(Chardev *s, int cmd, void *arg);
int (*get_msgfds)(Chardev *s, int* fds, int num);
int (*set_msgfds)(Chardev *s, int *fds, int num);
int (*chr_add_client)(Chardev *chr, int fd);
int (*chr_wait_connected)(Chardev *chr, Error **errp);
void (*chr_disconnect)(Chardev *chr);
void (*chr_accept_input)(Chardev *chr);
void (*chr_set_echo)(Chardev *chr, bool echo);
void (*chr_set_fe_open)(Chardev *chr, int fe_open);
void (*chr_be_event)(Chardev *s, QEMUChrEvent event);
void (*chr_options_parsed)(Chardev *chr);
};
Chardev *qemu_chardev_new(const char *id, const char *typename,
ChardevBackend *backend, GMainContext *context,
Error **errp);
extern int term_escape_char;
GSource *qemu_chr_timeout_add_ms(Chardev *chr, guint ms,
GSourceFunc func, void *private);
void suspend_mux_open(void);
void resume_mux_open(void);
/* console.c */
void qemu_chr_parse_vc(QemuOpts *opts, ChardevBackend *backend, Error **errp);
#endif