qemu-char.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-common.h"
#include "net.h"
#include "monitor.h"
#include "console.h"
#include "sysemu.h"
#include "qemu-timer.h"
#include "qemu-char.h"
#include "block.h"
#include "hw/usb.h"
#include "hw/baum.h"
#include "hw/msmouse.h"

#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <time.h>
#include <errno.h>
#include <sys/time.h>
#include <zlib.h>

#ifndef _WIN32
#include <sys/times.h>
#include <sys/wait.h>
#include <termios.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>
#ifdef __NetBSD__
#include <net/if_tap.h>
#endif
#ifdef __linux__
#include <linux/if_tun.h>
#endif
#include <arpa/inet.h>
#include <dirent.h>
#include <netdb.h>
#include <sys/select.h>
#ifdef CONFIG_BSD
#include <sys/stat.h>
#ifdef __FreeBSD__
#include <libutil.h>
#include <dev/ppbus/ppi.h>
#include <dev/ppbus/ppbconf.h>
#elif defined(__DragonFly__)
#include <libutil.h>
#include <dev/misc/ppi/ppi.h>
#include <bus/ppbus/ppbconf.h>
#else
#include <util.h>
#endif
#elif defined (__GLIBC__) && defined (__FreeBSD_kernel__)
#include <freebsd/stdlib.h>
#else
#ifdef __linux__
#include <pty.h>

#include <linux/ppdev.h>
#include <linux/parport.h>
#endif
#ifdef __sun__
#include <sys/stat.h>
#include <sys/ethernet.h>
#include <sys/sockio.h>
#include <netinet/arp.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h> // must come after ip.h
#include <netinet/udp.h>
#include <netinet/tcp.h>
#include <net/if.h>
#include <syslog.h>
#include <stropts.h>
#endif
#endif
#endif

#include "qemu_socket.h"

/***********************************************************/
/* character device */

static QTAILQ_HEAD(CharDriverStateHead, CharDriverState) chardevs =
    QTAILQ_HEAD_INITIALIZER(chardevs);
static int initial_reset_issued;

static void qemu_chr_event(CharDriverState *s, int event)
{
    if (!s->chr_event)
        return;
    s->chr_event(s->handler_opaque, event);
}

static void qemu_chr_reset_bh(void *opaque)
{
    CharDriverState *s = opaque;
    qemu_chr_event(s, CHR_EVENT_RESET);
    qemu_bh_delete(s->bh);
    s->bh = NULL;
}

void qemu_chr_reset(CharDriverState *s)
{
    if (s->bh == NULL && initial_reset_issued) {
	s->bh = qemu_bh_new(qemu_chr_reset_bh, s);
	qemu_bh_schedule(s->bh);
    }
}

void qemu_chr_initial_reset(void)
{
    CharDriverState *chr;

    initial_reset_issued = 1;

    QTAILQ_FOREACH(chr, &chardevs, next) {
        qemu_chr_reset(chr);
    }
}

int qemu_chr_write(CharDriverState *s, const uint8_t *buf, int len)
{
    return s->chr_write(s, buf, len);
}

int qemu_chr_ioctl(CharDriverState *s, int cmd, void *arg)
{
    if (!s->chr_ioctl)
        return -ENOTSUP;
    return s->chr_ioctl(s, cmd, arg);
}

int qemu_chr_can_read(CharDriverState *s)
{
    if (!s->chr_can_read)
        return 0;
    return s->chr_can_read(s->handler_opaque);
}

void qemu_chr_read(CharDriverState *s, uint8_t *buf, int len)
{
    s->chr_read(s->handler_opaque, buf, len);
}

int qemu_chr_get_msgfd(CharDriverState *s)
{
    return s->get_msgfd ? s->get_msgfd(s) : -1;
}

void qemu_chr_accept_input(CharDriverState *s)
{
    if (s->chr_accept_input)
        s->chr_accept_input(s);
}

void qemu_chr_printf(CharDriverState *s, const char *fmt, ...)
{
    char buf[4096];
    va_list ap;
    va_start(ap, fmt);
    vsnprintf(buf, sizeof(buf), fmt, ap);
    qemu_chr_write(s, (uint8_t *)buf, strlen(buf));
    va_end(ap);
}

void qemu_chr_send_event(CharDriverState *s, int event)
{
    if (s->chr_send_event)
        s->chr_send_event(s, event);
}

void qemu_chr_add_handlers(CharDriverState *s,
                           IOCanRWHandler *fd_can_read,
                           IOReadHandler *fd_read,
                           IOEventHandler *fd_event,
                           void *opaque)
{
    s->chr_can_read = fd_can_read;
    s->chr_read = fd_read;
    s->chr_event = fd_event;
    s->handler_opaque = opaque;
    if (s->chr_update_read_handler)
        s->chr_update_read_handler(s);
}

static int null_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
{
    return len;
}

static CharDriverState *qemu_chr_open_null(QemuOpts *opts)
{
    CharDriverState *chr;

    chr = qemu_mallocz(sizeof(CharDriverState));
    chr->chr_write = null_chr_write;
    return chr;
}

/* MUX driver for serial I/O splitting */
#define MAX_MUX 4
#define MUX_BUFFER_SIZE 32	/* Must be a power of 2.  */
#define MUX_BUFFER_MASK (MUX_BUFFER_SIZE - 1)
typedef struct {
    IOCanRWHandler *chr_can_read[MAX_MUX];
    IOReadHandler *chr_read[MAX_MUX];
    IOEventHandler *chr_event[MAX_MUX];
    void *ext_opaque[MAX_MUX];
    CharDriverState *drv;
    int focus;
    int mux_cnt;
    int term_got_escape;
    int max_size;
    /* Intermediate input buffer allows to catch escape sequences even if the
       currently active device is not accepting any input - but only until it
       is full as well. */
    unsigned char buffer[MAX_MUX][MUX_BUFFER_SIZE];
    int prod[MAX_MUX];
    int cons[MAX_MUX];
    int timestamps;
    int linestart;
    int64_t timestamps_start;
} MuxDriver;


static int mux_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
{
    MuxDriver *d = chr->opaque;
    int ret;
    if (!d->timestamps) {
        ret = d->drv->chr_write(d->drv, 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_get_clock(rt_clock);
                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));
                d->drv->chr_write(d->drv, (uint8_t *)buf1, strlen(buf1));
                d->linestart = 0;
            }
            ret += d->drv->chr_write(d->drv, 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(CharDriverState *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);
    }
    chr->chr_write(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] == '%')
                chr->chr_write(chr, (uint8_t *)ebuf, strlen(ebuf));
            else
                chr->chr_write(chr, (uint8_t *)&mux_help[i][j], 1);
        }
    }
}

static void mux_chr_send_event(MuxDriver *d, int mux_nr, int event)
{
    if (d->chr_event[mux_nr])
        d->chr_event[mux_nr](d->ext_opaque[mux_nr], event);
}

static int mux_proc_byte(CharDriverState *chr, MuxDriver *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";
                 chr->chr_write(chr,(uint8_t *)term,strlen(term));
                 exit(0);
                 break;
            }
        case 's':
            {
                DriveInfo *dinfo;
                QTAILQ_FOREACH(dinfo, &drives, next) {
                    bdrv_commit(dinfo->bdrv);
                }
            }
            break;
        case 'b':
            qemu_chr_event(chr, CHR_EVENT_BREAK);
            break;
        case 'c':
            /* Switch to the next registered device */
            mux_chr_send_event(d, d->focus, CHR_EVENT_MUX_OUT);
            d->focus++;
            if (d->focus >= d->mux_cnt)
                d->focus = 0;
            mux_chr_send_event(d, d->focus, CHR_EVENT_MUX_IN);
            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(CharDriverState *chr)
{
    MuxDriver *d = chr->opaque;
    int m = d->focus;

    while (d->prod[m] != d->cons[m] &&
           d->chr_can_read[m] &&
           d->chr_can_read[m](d->ext_opaque[m])) {
        d->chr_read[m](d->ext_opaque[m],
                       &d->buffer[m][d->cons[m]++ & MUX_BUFFER_MASK], 1);
    }
}

static int mux_chr_can_read(void *opaque)
{
    CharDriverState *chr = opaque;
    MuxDriver *d = chr->opaque;
    int m = d->focus;

    if ((d->prod[m] - d->cons[m]) < MUX_BUFFER_SIZE)
        return 1;
    if (d->chr_can_read[m])
        return d->chr_can_read[m](d->ext_opaque[m]);
    return 0;
}

static void mux_chr_read(void *opaque, const uint8_t *buf, int size)
{
    CharDriverState *chr = opaque;
    MuxDriver *d = chr->opaque;
    int m = d->focus;
    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] &&
                d->chr_can_read[m] &&
                d->chr_can_read[m](d->ext_opaque[m]))
                d->chr_read[m](d->ext_opaque[m], &buf[i], 1);
            else
                d->buffer[m][d->prod[m]++ & MUX_BUFFER_MASK] = buf[i];
        }
}

static void mux_chr_event(void *opaque, int event)
{
    CharDriverState *chr = opaque;
    MuxDriver *d = chr->opaque;
    int i;

    /* 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_update_read_handler(CharDriverState *chr)
{
    MuxDriver *d = chr->opaque;

    if (d->mux_cnt >= MAX_MUX) {
        fprintf(stderr, "Cannot add I/O handlers, MUX array is full\n");
        return;
    }
    d->ext_opaque[d->mux_cnt] = chr->handler_opaque;
    d->chr_can_read[d->mux_cnt] = chr->chr_can_read;
    d->chr_read[d->mux_cnt] = chr->chr_read;
    d->chr_event[d->mux_cnt] = chr->chr_event;
    /* Fix up the real driver with mux routines */
    if (d->mux_cnt == 0) {
        qemu_chr_add_handlers(d->drv, mux_chr_can_read, mux_chr_read,
                              mux_chr_event, chr);
    }
    if (d->focus != -1) {
        mux_chr_send_event(d, d->focus, CHR_EVENT_MUX_OUT);
    }
    d->focus = d->mux_cnt;
    d->mux_cnt++;
    mux_chr_send_event(d, d->focus, CHR_EVENT_MUX_IN);
}

static CharDriverState *qemu_chr_open_mux(CharDriverState *drv)
{
    CharDriverState *chr;
    MuxDriver *d;

    chr = qemu_mallocz(sizeof(CharDriverState));
    d = qemu_mallocz(sizeof(MuxDriver));

    chr->opaque = d;
    d->drv = drv;
    d->focus = -1;
    chr->chr_write = mux_chr_write;
    chr->chr_update_read_handler = mux_chr_update_read_handler;
    chr->chr_accept_input = mux_chr_accept_input;
    return chr;
}


#ifdef _WIN32
int send_all(int fd, const void *buf, int len1)
{
    int ret, len;

    len = len1;
    while (len > 0) {
        ret = send(fd, buf, len, 0);
        if (ret < 0) {
            errno = WSAGetLastError();
            if (errno != WSAEWOULDBLOCK) {
                return -1;
            }
        } else if (ret == 0) {
            break;
        } else {
            buf += ret;
            len -= ret;
        }
    }
    return len1 - len;
}

#else

static int unix_write(int fd, const uint8_t *buf, int len1)
{
    int ret, len;

    len = len1;
    while (len > 0) {
        ret = write(fd, buf, len);
        if (ret < 0) {
            if (errno != EINTR && errno != EAGAIN)
                return -1;
        } else if (ret == 0) {
            break;
        } else {
            buf += ret;
            len -= ret;
        }
    }
    return len1 - len;
}

int send_all(int fd, const void *buf, int len1)
{
    return unix_write(fd, buf, len1);
}
#endif /* !_WIN32 */

#ifndef _WIN32

typedef struct {
    int fd_in, fd_out;
    int max_size;
} FDCharDriver;

#define STDIO_MAX_CLIENTS 1
static int stdio_nb_clients = 0;

static int fd_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
{
    FDCharDriver *s = chr->opaque;
    return send_all(s->fd_out, buf, len);
}

static int fd_chr_read_poll(void *opaque)
{
    CharDriverState *chr = opaque;
    FDCharDriver *s = chr->opaque;

    s->max_size = qemu_chr_can_read(chr);
    return s->max_size;
}

static void fd_chr_read(void *opaque)
{
    CharDriverState *chr = opaque;
    FDCharDriver *s = chr->opaque;
    int size, len;
    uint8_t buf[1024];

    len = sizeof(buf);
    if (len > s->max_size)
        len = s->max_size;
    if (len == 0)
        return;
    size = read(s->fd_in, buf, len);
    if (size == 0) {
        /* FD has been closed. Remove it from the active list.  */
        qemu_set_fd_handler2(s->fd_in, NULL, NULL, NULL, NULL);
        qemu_chr_event(chr, CHR_EVENT_CLOSED);
        return;
    }
    if (size > 0) {
        qemu_chr_read(chr, buf, size);
    }
}

static void fd_chr_update_read_handler(CharDriverState *chr)
{
    FDCharDriver *s = chr->opaque;

    if (s->fd_in >= 0) {
        if (display_type == DT_NOGRAPHIC && s->fd_in == 0) {
        } else {
            qemu_set_fd_handler2(s->fd_in, fd_chr_read_poll,
                                 fd_chr_read, NULL, chr);
        }
    }
}

static void fd_chr_close(struct CharDriverState *chr)
{
    FDCharDriver *s = chr->opaque;

    if (s->fd_in >= 0) {
        if (display_type == DT_NOGRAPHIC && s->fd_in == 0) {
        } else {
            qemu_set_fd_handler2(s->fd_in, NULL, NULL, NULL, NULL);
        }
    }

    qemu_free(s);
    qemu_chr_event(chr, CHR_EVENT_CLOSED);
}

/* open a character device to a unix fd */
static CharDriverState *qemu_chr_open_fd(int fd_in, int fd_out)
{
    CharDriverState *chr;
    FDCharDriver *s;

    chr = qemu_mallocz(sizeof(CharDriverState));
    s = qemu_mallocz(sizeof(FDCharDriver));
    s->fd_in = fd_in;
    s->fd_out = fd_out;
    chr->opaque = s;
    chr->chr_write = fd_chr_write;
    chr->chr_update_read_handler = fd_chr_update_read_handler;
    chr->chr_close = fd_chr_close;

    qemu_chr_reset(chr);

    return chr;
}

static CharDriverState *qemu_chr_open_file_out(QemuOpts *opts)
{
    int fd_out;

    TFR(fd_out = open(qemu_opt_get(opts, "path"),
                      O_WRONLY | O_TRUNC | O_CREAT | O_BINARY, 0666));
    if (fd_out < 0)
        return NULL;
    return qemu_chr_open_fd(-1, fd_out);
}

static CharDriverState *qemu_chr_open_pipe(QemuOpts *opts)
{
    int fd_in, fd_out;
    char filename_in[256], filename_out[256];
    const char *filename = qemu_opt_get(opts, "path");

    if (filename == NULL) {
        fprintf(stderr, "chardev: pipe: no filename given\n");
        return NULL;
    }

    snprintf(filename_in, 256, "%s.in", filename);
    snprintf(filename_out, 256, "%s.out", filename);
    TFR(fd_in = open(filename_in, O_RDWR | O_BINARY));
    TFR(fd_out = open(filename_out, O_RDWR | O_BINARY));
    if (fd_in < 0 || fd_out < 0) {
	if (fd_in >= 0)
	    close(fd_in);
	if (fd_out >= 0)
	    close(fd_out);
        TFR(fd_in = fd_out = open(filename, O_RDWR | O_BINARY));
        if (fd_in < 0)
            return NULL;
    }
    return qemu_chr_open_fd(fd_in, fd_out);
}


/* for STDIO, we handle the case where several clients use it
   (nographic mode) */

#define TERM_FIFO_MAX_SIZE 1

static uint8_t term_fifo[TERM_FIFO_MAX_SIZE];
static int term_fifo_size;

static int stdio_read_poll(void *opaque)
{
    CharDriverState *chr = opaque;

    /* try to flush the queue if needed */
    if (term_fifo_size != 0 && qemu_chr_can_read(chr) > 0) {
        qemu_chr_read(chr, term_fifo, 1);
        term_fifo_size = 0;
    }
    /* see if we can absorb more chars */
    if (term_fifo_size == 0)
        return 1;
    else
        return 0;
}

static void stdio_read(void *opaque)
{
    int size;
    uint8_t buf[1];
    CharDriverState *chr = opaque;

    size = read(0, buf, 1);
    if (size == 0) {
        /* stdin has been closed. Remove it from the active list.  */
        qemu_set_fd_handler2(0, NULL, NULL, NULL, NULL);
        qemu_chr_event(chr, CHR_EVENT_CLOSED);
        return;
    }
    if (size > 0) {
        if (qemu_chr_can_read(chr) > 0) {
            qemu_chr_read(chr, buf, 1);
        } else if (term_fifo_size == 0) {
            term_fifo[term_fifo_size++] = buf[0];
        }
    }
}

/* init terminal so that we can grab keys */
static struct termios oldtty;
static int old_fd0_flags;
static int term_atexit_done;

static void term_exit(void)
{
    tcsetattr (0, TCSANOW, &oldtty);
    fcntl(0, F_SETFL, old_fd0_flags);
}

static void term_init(void)
{
    struct termios tty;

    tcgetattr (0, &tty);
    oldtty = tty;
    old_fd0_flags = fcntl(0, F_GETFL);

    tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
                          |INLCR|IGNCR|ICRNL|IXON);
    tty.c_oflag |= OPOST;
    tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN);
    /* if graphical mode, we allow Ctrl-C handling */
    if (display_type == DT_NOGRAPHIC)
        tty.c_lflag &= ~ISIG;
    tty.c_cflag &= ~(CSIZE|PARENB);
    tty.c_cflag |= CS8;
    tty.c_cc[VMIN] = 1;
    tty.c_cc[VTIME] = 0;

    tcsetattr (0, TCSANOW, &tty);

    if (!term_atexit_done++)
        atexit(term_exit);

    fcntl(0, F_SETFL, O_NONBLOCK);
}

static void qemu_chr_close_stdio(struct CharDriverState *chr)
{
    term_exit();
    stdio_nb_clients--;
    qemu_set_fd_handler2(0, NULL, NULL, NULL, NULL);
    fd_chr_close(chr);
}

static CharDriverState *qemu_chr_open_stdio(QemuOpts *opts)
{
    CharDriverState *chr;

    if (stdio_nb_clients >= STDIO_MAX_CLIENTS)
        return NULL;
    chr = qemu_chr_open_fd(0, 1);
    chr->chr_close = qemu_chr_close_stdio;
    qemu_set_fd_handler2(0, stdio_read_poll, stdio_read, NULL, chr);
    stdio_nb_clients++;
    term_init();

    return chr;
}

#ifdef __sun__
/* Once Solaris has openpty(), this is going to be removed. */
static int openpty(int *amaster, int *aslave, char *name,
                   struct termios *termp, struct winsize *winp)
{
        const char *slave;
        int mfd = -1, sfd = -1;

        *amaster = *aslave = -1;

        mfd = open("/dev/ptmx", O_RDWR | O_NOCTTY);
        if (mfd < 0)
                goto err;

        if (grantpt(mfd) == -1 || unlockpt(mfd) == -1)
                goto err;

        if ((slave = ptsname(mfd)) == NULL)
                goto err;

        if ((sfd = open(slave, O_RDONLY | O_NOCTTY)) == -1)
                goto err;

        if (ioctl(sfd, I_PUSH, "ptem") == -1 ||
            (termp != NULL && tcgetattr(sfd, termp) < 0))
                goto err;

        if (amaster)
                *amaster = mfd;
        if (aslave)
                *aslave = sfd;
        if (winp)
                ioctl(sfd, TIOCSWINSZ, winp);

        return 0;

err:
        if (sfd != -1)
                close(sfd);
        close(mfd);
        return -1;
}

static void cfmakeraw (struct termios *termios_p)
{
        termios_p->c_iflag &=
                ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON);
        termios_p->c_oflag &= ~OPOST;
        termios_p->c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
        termios_p->c_cflag &= ~(CSIZE|PARENB);
        termios_p->c_cflag |= CS8;

        termios_p->c_cc[VMIN] = 0;
        termios_p->c_cc[VTIME] = 0;
}
#endif

#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
    || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)

typedef struct {
    int fd;
    int connected;
    int polling;
    int read_bytes;
    QEMUTimer *timer;
} PtyCharDriver;

static void pty_chr_update_read_handler(CharDriverState *chr);
static void pty_chr_state(CharDriverState *chr, int connected);

static int pty_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
{
    PtyCharDriver *s = chr->opaque;

    if (!s->connected) {
        /* guest sends data, check for (re-)connect */
        pty_chr_update_read_handler(chr);
        return 0;
    }
    return send_all(s->fd, buf, len);
}

static int pty_chr_read_poll(void *opaque)
{
    CharDriverState *chr = opaque;
    PtyCharDriver *s = chr->opaque;

    s->read_bytes = qemu_chr_can_read(chr);
    return s->read_bytes;
}

static void pty_chr_read(void *opaque)
{
    CharDriverState *chr = opaque;
    PtyCharDriver *s = chr->opaque;
    int size, len;
    uint8_t buf[1024];

    len = sizeof(buf);
    if (len > s->read_bytes)
        len = s->read_bytes;
    if (len == 0)
        return;
    size = read(s->fd, buf, len);
    if ((size == -1 && errno == EIO) ||
        (size == 0)) {
        pty_chr_state(chr, 0);
        return;
    }
    if (size > 0) {
        pty_chr_state(chr, 1);
        qemu_chr_read(chr, buf, size);
    }
}

static void pty_chr_update_read_handler(CharDriverState *chr)
{
    PtyCharDriver *s = chr->opaque;

    qemu_set_fd_handler2(s->fd, pty_chr_read_poll,
                         pty_chr_read, NULL, chr);
    s->polling = 1;
    /*
     * Short timeout here: just need wait long enougth that qemu makes
     * it through the poll loop once.  When reconnected we want a
     * short timeout so we notice it almost instantly.  Otherwise
     * read() gives us -EIO instantly, making pty_chr_state() reset the
     * timeout to the normal (much longer) poll interval before the
     * timer triggers.
     */
    qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 10);
}

static void pty_chr_state(CharDriverState *chr, int connected)
{
    PtyCharDriver *s = chr->opaque;

    if (!connected) {
        qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
        s->connected = 0;
        s->polling = 0;
        /* (re-)connect poll interval for idle guests: once per second.
         * We check more frequently in case the guests sends data to
         * the virtual device linked to our pty. */
        qemu_mod_timer(s->timer, qemu_get_clock(rt_clock) + 1000);
    } else {
        if (!s->connected)
            qemu_chr_reset(chr);
        s->connected = 1;
    }
}

static void pty_chr_timer(void *opaque)
{
    struct CharDriverState *chr = opaque;
    PtyCharDriver *s = chr->opaque;

    if (s->connected)
        return;
    if (s->polling) {
        /* If we arrive here without polling being cleared due
         * read returning -EIO, then we are (re-)connected */
        pty_chr_state(chr, 1);
        return;
    }

    /* Next poll ... */
    pty_chr_update_read_handler(chr);
}

static void pty_chr_close(struct CharDriverState *chr)
{
    PtyCharDriver *s = chr->opaque;

    qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
    close(s->fd);
    qemu_del_timer(s->timer);
    qemu_free_timer(s->timer);
    qemu_free(s);
    qemu_chr_event(chr, CHR_EVENT_CLOSED);
}

static CharDriverState *qemu_chr_open_pty(QemuOpts *opts)
{
    CharDriverState *chr;
    PtyCharDriver *s;
    struct termios tty;
    int slave_fd, len;
#if defined(__OpenBSD__) || defined(__DragonFly__)
    char pty_name[PATH_MAX];
#define q_ptsname(x) pty_name
#else
    char *pty_name = NULL;
#define q_ptsname(x) ptsname(x)
#endif

    chr = qemu_mallocz(sizeof(CharDriverState));
    s = qemu_mallocz(sizeof(PtyCharDriver));

    if (openpty(&s->fd, &slave_fd, pty_name, NULL, NULL) < 0) {
        return NULL;
    }

    /* Set raw attributes on the pty. */
    tcgetattr(slave_fd, &tty);
    cfmakeraw(&tty);
    tcsetattr(slave_fd, TCSAFLUSH, &tty);
    close(slave_fd);

    len = strlen(q_ptsname(s->fd)) + 5;
    chr->filename = qemu_malloc(len);
    snprintf(chr->filename, len, "pty:%s", q_ptsname(s->fd));
    qemu_opt_set(opts, "path", q_ptsname(s->fd));
    fprintf(stderr, "char device redirected to %s\n", q_ptsname(s->fd));

    chr->opaque = s;
    chr->chr_write = pty_chr_write;
    chr->chr_update_read_handler = pty_chr_update_read_handler;
    chr->chr_close = pty_chr_close;

    s->timer = qemu_new_timer(rt_clock, pty_chr_timer, chr);

    return chr;
}

static void tty_serial_init(int fd, int speed,
                            int parity, int data_bits, int stop_bits)
{
    struct termios tty;
    speed_t spd;

#if 0
    printf("tty_serial_init: speed=%d parity=%c data=%d stop=%d\n",
           speed, parity, data_bits, stop_bits);
#endif
    tcgetattr (fd, &tty);

#define MARGIN 1.1
    if (speed <= 50 * MARGIN)
        spd = B50;
    else if (speed <= 75 * MARGIN)
        spd = B75;
    else if (speed <= 300 * MARGIN)
        spd = B300;
    else if (speed <= 600 * MARGIN)
        spd = B600;
    else if (speed <= 1200 * MARGIN)
        spd = B1200;
    else if (speed <= 2400 * MARGIN)
        spd = B2400;
    else if (speed <= 4800 * MARGIN)
        spd = B4800;
    else if (speed <= 9600 * MARGIN)
        spd = B9600;
    else if (speed <= 19200 * MARGIN)
        spd = B19200;
    else if (speed <= 38400 * MARGIN)
        spd = B38400;
    else if (speed <= 57600 * MARGIN)
        spd = B57600;
    else if (speed <= 115200 * MARGIN)
        spd = B115200;
    else
        spd = B115200;

    cfsetispeed(&tty, spd);
    cfsetospeed(&tty, spd);

    tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
                          |INLCR|IGNCR|ICRNL|IXON);
    tty.c_oflag |= OPOST;
    tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN|ISIG);
    tty.c_cflag &= ~(CSIZE|PARENB|PARODD|CRTSCTS|CSTOPB);
    switch(data_bits) {
    default:
    case 8:
        tty.c_cflag |= CS8;
        break;
    case 7:
        tty.c_cflag |= CS7;
        break;
    case 6:
        tty.c_cflag |= CS6;
        break;
    case 5:
        tty.c_cflag |= CS5;
        break;
    }
    switch(parity) {
    default:
    case 'N':
        break;
    case 'E':
        tty.c_cflag |= PARENB;
        break;
    case 'O':
        tty.c_cflag |= PARENB | PARODD;
        break;
    }
    if (stop_bits == 2)
        tty.c_cflag |= CSTOPB;

    tcsetattr (fd, TCSANOW, &tty);
}

static int tty_serial_ioctl(CharDriverState *chr, int cmd, void *arg)
{
    FDCharDriver *s = chr->opaque;

    switch(cmd) {
    case CHR_IOCTL_SERIAL_SET_PARAMS:
        {
            QEMUSerialSetParams *ssp = arg;
            tty_serial_init(s->fd_in, ssp->speed, ssp->parity,
                            ssp->data_bits, ssp->stop_bits);
        }
        break;
    case CHR_IOCTL_SERIAL_SET_BREAK:
        {
            int enable = *(int *)arg;
            if (enable)
                tcsendbreak(s->fd_in, 1);
        }
        break;
    case CHR_IOCTL_SERIAL_GET_TIOCM:
        {
            int sarg = 0;
            int *targ = (int *)arg;
            ioctl(s->fd_in, TIOCMGET, &sarg);
            *targ = 0;
            if (sarg & TIOCM_CTS)
                *targ |= CHR_TIOCM_CTS;
            if (sarg & TIOCM_CAR)
                *targ |= CHR_TIOCM_CAR;
            if (sarg & TIOCM_DSR)
                *targ |= CHR_TIOCM_DSR;
            if (sarg & TIOCM_RI)
                *targ |= CHR_TIOCM_RI;
            if (sarg & TIOCM_DTR)
                *targ |= CHR_TIOCM_DTR;
            if (sarg & TIOCM_RTS)
                *targ |= CHR_TIOCM_RTS;
        }
        break;
    case CHR_IOCTL_SERIAL_SET_TIOCM:
        {
            int sarg = *(int *)arg;
            int targ = 0;
            ioctl(s->fd_in, TIOCMGET, &targ);
            targ &= ~(CHR_TIOCM_CTS | CHR_TIOCM_CAR | CHR_TIOCM_DSR
                     | CHR_TIOCM_RI | CHR_TIOCM_DTR | CHR_TIOCM_RTS);
            if (sarg & CHR_TIOCM_CTS)
                targ |= TIOCM_CTS;
            if (sarg & CHR_TIOCM_CAR)
                targ |= TIOCM_CAR;
            if (sarg & CHR_TIOCM_DSR)
                targ |= TIOCM_DSR;
            if (sarg & CHR_TIOCM_RI)
                targ |= TIOCM_RI;
            if (sarg & CHR_TIOCM_DTR)
                targ |= TIOCM_DTR;
            if (sarg & CHR_TIOCM_RTS)
                targ |= TIOCM_RTS;
            ioctl(s->fd_in, TIOCMSET, &targ);
        }
        break;
    default:
        return -ENOTSUP;
    }
    return 0;
}

static CharDriverState *qemu_chr_open_tty(QemuOpts *opts)
{
    const char *filename = qemu_opt_get(opts, "path");
    CharDriverState *chr;
    int fd;

    TFR(fd = open(filename, O_RDWR | O_NONBLOCK));
    tty_serial_init(fd, 115200, 'N', 8, 1);
    chr = qemu_chr_open_fd(fd, fd);
    if (!chr) {
        close(fd);
        return NULL;
    }
    chr->chr_ioctl = tty_serial_ioctl;
    qemu_chr_reset(chr);
    return chr;
}
#else  /* ! __linux__ && ! __sun__ */
static CharDriverState *qemu_chr_open_pty(void)
{
    return NULL;
}
#endif /* __linux__ || __sun__ */

#if defined(__linux__)
typedef struct {
    int fd;
    int mode;
} ParallelCharDriver;

static int pp_hw_mode(ParallelCharDriver *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(CharDriverState *chr, int cmd, void *arg)
{
    ParallelCharDriver *drv = chr->opaque;
    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 pp_close(CharDriverState *chr)
{
    ParallelCharDriver *drv = chr->opaque;
    int fd = drv->fd;

    pp_hw_mode(drv, IEEE1284_MODE_COMPAT);
    ioctl(fd, PPRELEASE);
    close(fd);
    qemu_free(drv);
    qemu_chr_event(chr, CHR_EVENT_CLOSED);
}

static CharDriverState *qemu_chr_open_pp(QemuOpts *opts)
{
    const char *filename = qemu_opt_get(opts, "path");
    CharDriverState *chr;
    ParallelCharDriver *drv;
    int fd;

    TFR(fd = open(filename, O_RDWR));
    if (fd < 0)
        return NULL;

    if (ioctl(fd, PPCLAIM) < 0) {
        close(fd);
        return NULL;
    }

    drv = qemu_mallocz(sizeof(ParallelCharDriver));
    drv->fd = fd;
    drv->mode = IEEE1284_MODE_COMPAT;

    chr = qemu_mallocz(sizeof(CharDriverState));
    chr->chr_write = null_chr_write;
    chr->chr_ioctl = pp_ioctl;
    chr->chr_close = pp_close;
    chr->opaque = drv;

    qemu_chr_reset(chr);

    return chr;
}
#endif /* __linux__ */

#if defined(__FreeBSD__) || defined(__DragonFly__)
static int pp_ioctl(CharDriverState *chr, int cmd, void *arg)
{
    int fd = (int)chr->opaque;
    uint8_t b;

    switch(cmd) {
    case CHR_IOCTL_PP_READ_DATA:
        if (ioctl(fd, PPIGDATA, &b) < 0)
            return -ENOTSUP;
        *(uint8_t *)arg = b;
        break;
    case CHR_IOCTL_PP_WRITE_DATA:
        b = *(uint8_t *)arg;
        if (ioctl(fd, PPISDATA, &b) < 0)
            return -ENOTSUP;
        break;
    case CHR_IOCTL_PP_READ_CONTROL:
        if (ioctl(fd, PPIGCTRL, &b) < 0)
            return -ENOTSUP;
        *(uint8_t *)arg = b;
        break;
    case CHR_IOCTL_PP_WRITE_CONTROL:
        b = *(uint8_t *)arg;
        if (ioctl(fd, PPISCTRL, &b) < 0)
            return -ENOTSUP;
        break;
    case CHR_IOCTL_PP_READ_STATUS:
        if (ioctl(fd, PPIGSTATUS, &b) < 0)
            return -ENOTSUP;
        *(uint8_t *)arg = b;
        break;
    default:
        return -ENOTSUP;
    }
    return 0;
}

static CharDriverState *qemu_chr_open_pp(QemuOpts *opts)
{
    const char *filename = qemu_opt_get(opts, "path");
    CharDriverState *chr;
    int fd;

    fd = open(filename, O_RDWR);
    if (fd < 0)
        return NULL;

    chr = qemu_mallocz(sizeof(CharDriverState));
    chr->opaque = (void *)fd;
    chr->chr_write = null_chr_write;
    chr->chr_ioctl = pp_ioctl;
    return chr;
}
#endif

#else /* _WIN32 */

typedef struct {
    int max_size;
    HANDLE hcom, hrecv, hsend;
    OVERLAPPED orecv, osend;
    BOOL fpipe;
    DWORD len;
} WinCharState;

#define NSENDBUF 2048
#define NRECVBUF 2048
#define MAXCONNECT 1
#define NTIMEOUT 5000

static int win_chr_poll(void *opaque);
static int win_chr_pipe_poll(void *opaque);

static void win_chr_close(CharDriverState *chr)
{
    WinCharState *s = chr->opaque;

    if (s->hsend) {
        CloseHandle(s->hsend);
        s->hsend = NULL;
    }
    if (s->hrecv) {
        CloseHandle(s->hrecv);
        s->hrecv = NULL;
    }
    if (s->hcom) {
        CloseHandle(s->hcom);
        s->hcom = NULL;
    }
    if (s->fpipe)
        qemu_del_polling_cb(win_chr_pipe_poll, chr);
    else
        qemu_del_polling_cb(win_chr_poll, chr);

    qemu_chr_event(chr, CHR_EVENT_CLOSED);
}

static int win_chr_init(CharDriverState *chr, const char *filename)
{
    WinCharState *s = chr->opaque;
    COMMCONFIG comcfg;
    COMMTIMEOUTS cto = { 0, 0, 0, 0, 0};
    COMSTAT comstat;
    DWORD size;
    DWORD err;

    s->hsend = CreateEvent(NULL, TRUE, FALSE, NULL);
    if (!s->hsend) {
        fprintf(stderr, "Failed CreateEvent\n");
        goto fail;
    }
    s->hrecv = CreateEvent(NULL, TRUE, FALSE, NULL);
    if (!s->hrecv) {
        fprintf(stderr, "Failed CreateEvent\n");
        goto fail;
    }

    s->hcom = CreateFile(filename, GENERIC_READ|GENERIC_WRITE, 0, NULL,
                      OPEN_EXISTING, FILE_FLAG_OVERLAPPED, 0);
    if (s->hcom == INVALID_HANDLE_VALUE) {
        fprintf(stderr, "Failed CreateFile (%lu)\n", GetLastError());
        s->hcom = NULL;
        goto fail;
    }

    if (!SetupComm(s->hcom, NRECVBUF, NSENDBUF)) {
        fprintf(stderr, "Failed SetupComm\n");
        goto fail;
    }

    ZeroMemory(&comcfg, sizeof(COMMCONFIG));
    size = sizeof(COMMCONFIG);
    GetDefaultCommConfig(filename, &comcfg, &size);
    comcfg.dcb.DCBlength = sizeof(DCB);
    CommConfigDialog(filename, NULL, &comcfg);

    if (!SetCommState(s->hcom, &comcfg.dcb)) {
        fprintf(stderr, "Failed SetCommState\n");
        goto fail;
    }

    if (!SetCommMask(s->hcom, EV_ERR)) {
        fprintf(stderr, "Failed SetCommMask\n");
        goto fail;
    }

    cto.ReadIntervalTimeout = MAXDWORD;
    if (!SetCommTimeouts(s->hcom, &cto)) {
        fprintf(stderr, "Failed SetCommTimeouts\n");
        goto fail;
    }

    if (!ClearCommError(s->hcom, &err, &comstat)) {
        fprintf(stderr, "Failed ClearCommError\n");
        goto fail;
    }
    qemu_add_polling_cb(win_chr_poll, chr);
    return 0;

 fail:
    win_chr_close(chr);
    return -1;
}

static int win_chr_write(CharDriverState *chr, const uint8_t *buf, int len1)
{
    WinCharState *s = chr->opaque;
    DWORD len, ret, size, err;

    len = len1;
    ZeroMemory(&s->osend, sizeof(s->osend));
    s->osend.hEvent = s->hsend;
    while (len > 0) {
        if (s->hsend)
            ret = WriteFile(s->hcom, buf, len, &size, &s->osend);
        else
            ret = WriteFile(s->hcom, buf, len, &size, NULL);
        if (!ret) {
            err = GetLastError();
            if (err == ERROR_IO_PENDING) {
                ret = GetOverlappedResult(s->hcom, &s->osend, &size, TRUE);
                if (ret) {
                    buf += size;
                    len -= size;
                } else {
                    break;
                }
            } else {
                break;
            }
        } else {
            buf += size;
            len -= size;
        }
    }
    return len1 - len;
}

static int win_chr_read_poll(CharDriverState *chr)
{
    WinCharState *s = chr->opaque;

    s->max_size = qemu_chr_can_read(chr);
    return s->max_size;
}

static void win_chr_readfile(CharDriverState *chr)
{
    WinCharState *s = chr->opaque;
    int ret, err;
    uint8_t buf[1024];
    DWORD size;

    ZeroMemory(&s->orecv, sizeof(s->orecv));
    s->orecv.hEvent = s->hrecv;
    ret = ReadFile(s->hcom, buf, s->len, &size, &s->orecv);
    if (!ret) {
        err = GetLastError();
        if (err == ERROR_IO_PENDING) {
            ret = GetOverlappedResult(s->hcom, &s->orecv, &size, TRUE);
        }
    }

    if (size > 0) {
        qemu_chr_read(chr, buf, size);
    }
}

static void win_chr_read(CharDriverState *chr)
{
    WinCharState *s = chr->opaque;

    if (s->len > s->max_size)
        s->len = s->max_size;
    if (s->len == 0)
        return;

    win_chr_readfile(chr);
}

static int win_chr_poll(void *opaque)
{
    CharDriverState *chr = opaque;
    WinCharState *s = chr->opaque;
    COMSTAT status;
    DWORD comerr;

    ClearCommError(s->hcom, &comerr, &status);
    if (status.cbInQue > 0) {
        s->len = status.cbInQue;
        win_chr_read_poll(chr);
        win_chr_read(chr);
        return 1;
    }
    return 0;
}

static CharDriverState *qemu_chr_open_win(QemuOpts *opts)
{
    const char *filename = qemu_opt_get(opts, "path");
    CharDriverState *chr;
    WinCharState *s;

    chr = qemu_mallocz(sizeof(CharDriverState));
    s = qemu_mallocz(sizeof(WinCharState));
    chr->opaque = s;
    chr->chr_write = win_chr_write;
    chr->chr_close = win_chr_close;

    if (win_chr_init(chr, filename) < 0) {
        free(s);
        free(chr);
        return NULL;
    }
    qemu_chr_reset(chr);
    return chr;
}

static int win_chr_pipe_poll(void *opaque)
{
    CharDriverState *chr = opaque;
    WinCharState *s = chr->opaque;
    DWORD size;

    PeekNamedPipe(s->hcom, NULL, 0, NULL, &size, NULL);
    if (size > 0) {
        s->len = size;
        win_chr_read_poll(chr);
        win_chr_read(chr);
        return 1;
    }
    return 0;
}

static int win_chr_pipe_init(CharDriverState *chr, const char *filename)
{
    WinCharState *s = chr->opaque;
    OVERLAPPED ov;
    int ret;
    DWORD size;
    char openname[256];

    s->fpipe = TRUE;

    s->hsend = CreateEvent(NULL, TRUE, FALSE, NULL);
    if (!s->hsend) {
        fprintf(stderr, "Failed CreateEvent\n");
        goto fail;
    }
    s->hrecv = CreateEvent(NULL, TRUE, FALSE, NULL);
    if (!s->hrecv) {
        fprintf(stderr, "Failed CreateEvent\n");
        goto fail;
    }

    snprintf(openname, sizeof(openname), "\\\\.\\pipe\\%s", filename);
    s->hcom = CreateNamedPipe(openname, PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED,
                              PIPE_TYPE_BYTE | PIPE_READMODE_BYTE |
                              PIPE_WAIT,
                              MAXCONNECT, NSENDBUF, NRECVBUF, NTIMEOUT, NULL);
    if (s->hcom == INVALID_HANDLE_VALUE) {
        fprintf(stderr, "Failed CreateNamedPipe (%lu)\n", GetLastError());
        s->hcom = NULL;
        goto fail;
    }

    ZeroMemory(&ov, sizeof(ov));
    ov.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
    ret = ConnectNamedPipe(s->hcom, &ov);
    if (ret) {
        fprintf(stderr, "Failed ConnectNamedPipe\n");
        goto fail;
    }

    ret = GetOverlappedResult(s->hcom, &ov, &size, TRUE);
    if (!ret) {
        fprintf(stderr, "Failed GetOverlappedResult\n");
        if (ov.hEvent) {
            CloseHandle(ov.hEvent);
            ov.hEvent = NULL;
        }
        goto fail;
    }

    if (ov.hEvent) {
        CloseHandle(ov.hEvent);
        ov.hEvent = NULL;
    }
    qemu_add_polling_cb(win_chr_pipe_poll, chr);
    return 0;

 fail:
    win_chr_close(chr);
    return -1;
}


static CharDriverState *qemu_chr_open_win_pipe(QemuOpts *opts)
{
    const char *filename = qemu_opt_get(opts, "path");
    CharDriverState *chr;
    WinCharState *s;

    chr = qemu_mallocz(sizeof(CharDriverState));
    s = qemu_mallocz(sizeof(WinCharState));
    chr->opaque = s;
    chr->chr_write = win_chr_write;
    chr->chr_close = win_chr_close;

    if (win_chr_pipe_init(chr, filename) < 0) {
        free(s);
        free(chr);
        return NULL;
    }
    qemu_chr_reset(chr);
    return chr;
}

static CharDriverState *qemu_chr_open_win_file(HANDLE fd_out)
{
    CharDriverState *chr;
    WinCharState *s;

    chr = qemu_mallocz(sizeof(CharDriverState));
    s = qemu_mallocz(sizeof(WinCharState));
    s->hcom = fd_out;
    chr->opaque = s;
    chr->chr_write = win_chr_write;
    qemu_chr_reset(chr);
    return chr;
}

static CharDriverState *qemu_chr_open_win_con(QemuOpts *opts)
{
    return qemu_chr_open_win_file(GetStdHandle(STD_OUTPUT_HANDLE));
}

static CharDriverState *qemu_chr_open_win_file_out(QemuOpts *opts)
{
    const char *file_out = qemu_opt_get(opts, "path");
    HANDLE fd_out;

    fd_out = CreateFile(file_out, GENERIC_WRITE, FILE_SHARE_READ, NULL,
                        OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
    if (fd_out == INVALID_HANDLE_VALUE)
        return NULL;

    return qemu_chr_open_win_file(fd_out);
}
#endif /* !_WIN32 */

/***********************************************************/
/* UDP Net console */

typedef struct {
    int fd;
    uint8_t buf[1024];
    int bufcnt;
    int bufptr;
    int max_size;
} NetCharDriver;

static int udp_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
{
    NetCharDriver *s = chr->opaque;

    return send(s->fd, (const void *)buf, len, 0);
}

static int udp_chr_read_poll(void *opaque)
{
    CharDriverState *chr = opaque;
    NetCharDriver *s = chr->opaque;

    s->max_size = qemu_chr_can_read(chr);

    /* If there were any stray characters in the queue process them
     * first
     */
    while (s->max_size > 0 && s->bufptr < s->bufcnt) {
        qemu_chr_read(chr, &s->buf[s->bufptr], 1);
        s->bufptr++;
        s->max_size = qemu_chr_can_read(chr);
    }
    return s->max_size;
}

static void udp_chr_read(void *opaque)
{
    CharDriverState *chr = opaque;
    NetCharDriver *s = chr->opaque;

    if (s->max_size == 0)
        return;
    s->bufcnt = recv(s->fd, (void *)s->buf, sizeof(s->buf), 0);
    s->bufptr = s->bufcnt;
    if (s->bufcnt <= 0)
        return;

    s->bufptr = 0;
    while (s->max_size > 0 && s->bufptr < s->bufcnt) {
        qemu_chr_read(chr, &s->buf[s->bufptr], 1);
        s->bufptr++;
        s->max_size = qemu_chr_can_read(chr);
    }
}

static void udp_chr_update_read_handler(CharDriverState *chr)
{
    NetCharDriver *s = chr->opaque;

    if (s->fd >= 0) {
        qemu_set_fd_handler2(s->fd, udp_chr_read_poll,
                             udp_chr_read, NULL, chr);
    }
}

static void udp_chr_close(CharDriverState *chr)
{
    NetCharDriver *s = chr->opaque;
    if (s->fd >= 0) {
        qemu_set_fd_handler(s->fd, NULL, NULL, NULL);
        closesocket(s->fd);
    }
    qemu_free(s);
    qemu_chr_event(chr, CHR_EVENT_CLOSED);
}

static CharDriverState *qemu_chr_open_udp(QemuOpts *opts)
{
    CharDriverState *chr = NULL;
    NetCharDriver *s = NULL;
    int fd = -1;

    chr = qemu_mallocz(sizeof(CharDriverState));
    s = qemu_mallocz(sizeof(NetCharDriver));

    fd = inet_dgram_opts(opts);
    if (fd < 0) {
        fprintf(stderr, "inet_dgram_opts failed\n");
        goto return_err;
    }

    s->fd = fd;
    s->bufcnt = 0;
    s->bufptr = 0;
    chr->opaque = s;
    chr->chr_write = udp_chr_write;
    chr->chr_update_read_handler = udp_chr_update_read_handler;
    chr->chr_close = udp_chr_close;
    return chr;

return_err:
    if (chr)
        free(chr);
    if (s)
        free(s);
    if (fd >= 0)
        closesocket(fd);
    return NULL;
}

/***********************************************************/
/* TCP Net console */

typedef struct {
    int fd, listen_fd;
    int connected;
    int max_size;
    int do_telnetopt;
    int do_nodelay;
    int is_unix;
    int msgfd;
} TCPCharDriver;

static void tcp_chr_accept(void *opaque);

static int tcp_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
{
    TCPCharDriver *s = chr->opaque;
    if (s->connected) {
        return send_all(s->fd, buf, len);
    } else {
        /* XXX: indicate an error ? */
        return len;
    }
}

static int tcp_chr_read_poll(void *opaque)
{
    CharDriverState *chr = opaque;
    TCPCharDriver *s = chr->opaque;
    if (!s->connected)
        return 0;
    s->max_size = qemu_chr_can_read(chr);
    return s->max_size;
}

#define IAC 255
#define IAC_BREAK 243
static void tcp_chr_process_IAC_bytes(CharDriverState *chr,
                                      TCPCharDriver *s,
                                      uint8_t *buf, int *size)
{
    /* Handle any telnet client's basic IAC options to satisfy char by
     * char mode with no echo.  All IAC options will be removed from
     * the buf and the do_telnetopt variable will be used to track the
     * state of the width of the IAC information.
     *
     * IAC commands come in sets of 3 bytes with the exception of the
     * "IAC BREAK" command and the double IAC.
     */

    int i;
    int j = 0;

    for (i = 0; i < *size; i++) {
        if (s->do_telnetopt > 1) {
            if ((unsigned char)buf[i] == IAC && s->do_telnetopt == 2) {
                /* Double IAC means send an IAC */
                if (j != i)
                    buf[j] = buf[i];
                j++;
                s->do_telnetopt = 1;
            } else {
                if ((unsigned char)buf[i] == IAC_BREAK && s->do_telnetopt == 2) {
                    /* Handle IAC break commands by sending a serial break */
                    qemu_chr_event(chr, CHR_EVENT_BREAK);
                    s->do_telnetopt++;
                }
                s->do_telnetopt++;
            }
            if (s->do_telnetopt >= 4) {
                s->do_telnetopt = 1;
            }
        } else {
            if ((unsigned char)buf[i] == IAC) {
                s->do_telnetopt = 2;
            } else {
                if (j != i)
                    buf[j] = buf[i];
                j++;
            }
        }
    }
    *size = j;
}

static int tcp_get_msgfd(CharDriverState *chr)
{
    TCPCharDriver *s = chr->opaque;

    return s->msgfd;
}

#ifndef _WIN32
static void unix_process_msgfd(CharDriverState *chr, struct msghdr *msg)
{
    TCPCharDriver *s = chr->opaque;
    struct cmsghdr *cmsg;

    for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
        int fd;

        if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) ||
            cmsg->cmsg_level != SOL_SOCKET ||
            cmsg->cmsg_type != SCM_RIGHTS)
            continue;

        fd = *((int *)CMSG_DATA(cmsg));
        if (fd < 0)
            continue;

        if (s->msgfd != -1)
            close(s->msgfd);
        s->msgfd = fd;
    }
}

static ssize_t tcp_chr_recv(CharDriverState *chr, char *buf, size_t len)
{
    TCPCharDriver *s = chr->opaque;
    struct msghdr msg = { NULL, };
    struct iovec iov[1];
    union {
        struct cmsghdr cmsg;
        char control[CMSG_SPACE(sizeof(int))];
    } msg_control;
    ssize_t ret;

    iov[0].iov_base = buf;
    iov[0].iov_len = len;

    msg.msg_iov = iov;
    msg.msg_iovlen = 1;
    msg.msg_control = &msg_control;
    msg.msg_controllen = sizeof(msg_control);

    ret = recvmsg(s->fd, &msg, 0);
    if (ret > 0 && s->is_unix)
        unix_process_msgfd(chr, &msg);

    return ret;
}
#else
static ssize_t tcp_chr_recv(CharDriverState *chr, char *buf, size_t len)
{
    TCPCharDriver *s = chr->opaque;
    return recv(s->fd, buf, len, 0);
}
#endif

static void tcp_chr_read(void *opaque)
{
    CharDriverState *chr = opaque;
    TCPCharDriver *s = chr->opaque;
    uint8_t buf[1024];
    int len, size;

    if (!s->connected || s->max_size <= 0)
        return;
    len = sizeof(buf);
    if (len > s->max_size)
        len = s->max_size;
    size = tcp_chr_recv(chr, (void *)buf, len);
    if (size == 0) {
        /* connection closed */
        s->connected = 0;
        if (s->listen_fd >= 0) {
            qemu_set_fd_handler(s->listen_fd, tcp_chr_accept, NULL, chr);
        }
        qemu_set_fd_handler(s->fd, NULL, NULL, NULL);
        closesocket(s->fd);
        s->fd = -1;
        qemu_chr_event(chr, CHR_EVENT_CLOSED);
    } else if (size > 0) {
        if (s->do_telnetopt)
            tcp_chr_process_IAC_bytes(chr, s, buf, &size);
        if (size > 0)
            qemu_chr_read(chr, buf, size);
        if (s->msgfd != -1) {
            close(s->msgfd);
            s->msgfd = -1;
        }
    }
}

static void tcp_chr_connect(void *opaque)
{
    CharDriverState *chr = opaque;
    TCPCharDriver *s = chr->opaque;

    s->connected = 1;
    qemu_set_fd_handler2(s->fd, tcp_chr_read_poll,
                         tcp_chr_read, NULL, chr);
    qemu_chr_reset(chr);
}

#define IACSET(x,a,b,c) x[0] = a; x[1] = b; x[2] = c;
static void tcp_chr_telnet_init(int fd)
{
    char buf[3];
    /* Send the telnet negotion to put telnet in binary, no echo, single char mode */
    IACSET(buf, 0xff, 0xfb, 0x01);  /* IAC WILL ECHO */
    send(fd, (char *)buf, 3, 0);
    IACSET(buf, 0xff, 0xfb, 0x03);  /* IAC WILL Suppress go ahead */
    send(fd, (char *)buf, 3, 0);
    IACSET(buf, 0xff, 0xfb, 0x00);  /* IAC WILL Binary */
    send(fd, (char *)buf, 3, 0);
    IACSET(buf, 0xff, 0xfd, 0x00);  /* IAC DO Binary */
    send(fd, (char *)buf, 3, 0);
}

static void socket_set_nodelay(int fd)
{
    int val = 1;
    setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (char *)&val, sizeof(val));
}

static void tcp_chr_accept(void *opaque)
{
    CharDriverState *chr = opaque;
    TCPCharDriver *s = chr->opaque;
    struct sockaddr_in saddr;
#ifndef _WIN32
    struct sockaddr_un uaddr;
#endif
    struct sockaddr *addr;
    socklen_t len;
    int fd;

    for(;;) {
#ifndef _WIN32
	if (s->is_unix) {
	    len = sizeof(uaddr);
	    addr = (struct sockaddr *)&uaddr;
	} else
#endif
	{
	    len = sizeof(saddr);
	    addr = (struct sockaddr *)&saddr;
	}
        fd = accept(s->listen_fd, addr, &len);
        if (fd < 0 && errno != EINTR) {
            return;
        } else if (fd >= 0) {
            if (s->do_telnetopt)
                tcp_chr_telnet_init(fd);
            break;
        }
    }
    socket_set_nonblock(fd);
    if (s->do_nodelay)
        socket_set_nodelay(fd);
    s->fd = fd;
    qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
    tcp_chr_connect(chr);
}

static void tcp_chr_close(CharDriverState *chr)
{
    TCPCharDriver *s = chr->opaque;
    if (s->fd >= 0) {
        qemu_set_fd_handler(s->fd, NULL, NULL, NULL);
        closesocket(s->fd);
    }
    if (s->listen_fd >= 0) {
        qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
        closesocket(s->listen_fd);
    }
    qemu_free(s);
    qemu_chr_event(chr, CHR_EVENT_CLOSED);
}

static CharDriverState *qemu_chr_open_socket(QemuOpts *opts)
{
    CharDriverState *chr = NULL;
    TCPCharDriver *s = NULL;
    int fd = -1;
    int is_listen;
    int is_waitconnect;
    int do_nodelay;
    int is_unix;
    int is_telnet;

    is_listen      = qemu_opt_get_bool(opts, "server", 0);
    is_waitconnect = qemu_opt_get_bool(opts, "wait", 1);
    is_telnet      = qemu_opt_get_bool(opts, "telnet", 0);
    do_nodelay     = !qemu_opt_get_bool(opts, "delay", 1);
    is_unix        = qemu_opt_get(opts, "path") != NULL;
    if (!is_listen)
        is_waitconnect = 0;

    chr = qemu_mallocz(sizeof(CharDriverState));
    s = qemu_mallocz(sizeof(TCPCharDriver));

    if (is_unix) {
        if (is_listen) {
            fd = unix_listen_opts(opts);
        } else {
            fd = unix_connect_opts(opts);
        }
    } else {
        if (is_listen) {
            fd = inet_listen_opts(opts, 0);
        } else {
            fd = inet_connect_opts(opts);
        }
    }
    if (fd < 0)
        goto fail;

    if (!is_waitconnect)
        socket_set_nonblock(fd);

    s->connected = 0;
    s->fd = -1;
    s->listen_fd = -1;
    s->msgfd = -1;
    s->is_unix = is_unix;
    s->do_nodelay = do_nodelay && !is_unix;

    chr->opaque = s;
    chr->chr_write = tcp_chr_write;
    chr->chr_close = tcp_chr_close;
    chr->get_msgfd = tcp_get_msgfd;

    if (is_listen) {
        s->listen_fd = fd;
        qemu_set_fd_handler(s->listen_fd, tcp_chr_accept, NULL, chr);
        if (is_telnet)
            s->do_telnetopt = 1;

    } else {
        s->connected = 1;
        s->fd = fd;
        socket_set_nodelay(fd);
        tcp_chr_connect(chr);
    }

    /* for "info chardev" monitor command */
    chr->filename = qemu_malloc(256);
    if (is_unix) {
        snprintf(chr->filename, 256, "unix:%s%s",
                 qemu_opt_get(opts, "path"),
                 qemu_opt_get_bool(opts, "server", 0) ? ",server" : "");
    } else if (is_telnet) {
        snprintf(chr->filename, 256, "telnet:%s:%s%s",
                 qemu_opt_get(opts, "host"), qemu_opt_get(opts, "port"),
                 qemu_opt_get_bool(opts, "server", 0) ? ",server" : "");
    } else {
        snprintf(chr->filename, 256, "tcp:%s:%s%s",
                 qemu_opt_get(opts, "host"), qemu_opt_get(opts, "port"),
                 qemu_opt_get_bool(opts, "server", 0) ? ",server" : "");
    }

    if (is_listen && is_waitconnect) {
        printf("QEMU waiting for connection on: %s\n",
               chr->filename);
        tcp_chr_accept(chr);
        socket_set_nonblock(s->listen_fd);
    }
    return chr;

 fail:
    if (fd >= 0)
        closesocket(fd);
    qemu_free(s);
    qemu_free(chr);
    return NULL;
}

static QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename)
{
    char host[65], port[33], width[8], height[8];
    int pos;
    const char *p;
    QemuOpts *opts;

    opts = qemu_opts_create(&qemu_chardev_opts, label, 1);
    if (NULL == opts)
        return NULL;

    if (strstart(filename, "mon:", &p)) {
        filename = p;
        qemu_opt_set(opts, "mux", "on");
    }

    if (strcmp(filename, "null")    == 0 ||
        strcmp(filename, "pty")     == 0 ||
        strcmp(filename, "msmouse") == 0 ||
        strcmp(filename, "braille") == 0 ||
        strcmp(filename, "stdio")   == 0) {
        qemu_opt_set(opts, "backend", filename);
        return opts;
    }
    if (strstart(filename, "vc", &p)) {
        qemu_opt_set(opts, "backend", "vc");
        if (*p == ':') {
            if (sscanf(p+1, "%8[0-9]x%8[0-9]", width, height) == 2) {
                /* pixels */
                qemu_opt_set(opts, "width", width);
                qemu_opt_set(opts, "height", height);
            } else if (sscanf(p+1, "%8[0-9]Cx%8[0-9]C", width, height) == 2) {
                /* chars */
                qemu_opt_set(opts, "cols", width);
                qemu_opt_set(opts, "rows", height);
            } else {
                goto fail;
            }
        }
        return opts;
    }
    if (strcmp(filename, "con:") == 0) {
        qemu_opt_set(opts, "backend", "console");
        return opts;
    }
    if (strstart(filename, "COM", NULL)) {
        qemu_opt_set(opts, "backend", "serial");
        qemu_opt_set(opts, "path", filename);
        return opts;
    }
    if (strstart(filename, "file:", &p)) {
        qemu_opt_set(opts, "backend", "file");
        qemu_opt_set(opts, "path", p);
        return opts;
    }
    if (strstart(filename, "pipe:", &p)) {
        qemu_opt_set(opts, "backend", "pipe");
        qemu_opt_set(opts, "path", p);
        return opts;
    }
    if (strstart(filename, "tcp:", &p) ||
        strstart(filename, "telnet:", &p)) {
        if (sscanf(p, "%64[^:]:%32[^,]%n", host, port, &pos) < 2) {
            host[0] = 0;
            if (sscanf(p, ":%32[^,]%n", port, &pos) < 1)
                goto fail;
        }
        qemu_opt_set(opts, "backend", "socket");
        qemu_opt_set(opts, "host", host);
        qemu_opt_set(opts, "port", port);
        if (p[pos] == ',') {
            if (qemu_opts_do_parse(opts, p+pos+1, NULL) != 0)
                goto fail;
        }
        if (strstart(filename, "telnet:", &p))
            qemu_opt_set(opts, "telnet", "on");
        return opts;
    }
    if (strstart(filename, "udp:", &p)) {
        qemu_opt_set(opts, "backend", "udp");
        if (sscanf(p, "%64[^:]:%32[^@,]%n", host, port, &pos) < 2) {
            host[0] = 0;
            if (sscanf(p, ":%32[^,]%n", port, &pos) < 1) {
                fprintf(stderr, "udp #1\n");
                goto fail;
            }
        }
        qemu_opt_set(opts, "host", host);
        qemu_opt_set(opts, "port", port);
        if (p[pos] == '@') {
            p += pos + 1;
            if (sscanf(p, "%64[^:]:%32[^,]%n", host, port, &pos) < 2) {
                host[0] = 0;
                if (sscanf(p, ":%32[^,]%n", port, &pos) < 1) {
                    fprintf(stderr, "udp #2\n");
                    goto fail;
                }
            }
            qemu_opt_set(opts, "localaddr", host);
            qemu_opt_set(opts, "localport", port);
        }
        return opts;
    }
    if (strstart(filename, "unix:", &p)) {
        qemu_opt_set(opts, "backend", "socket");
        if (qemu_opts_do_parse(opts, p, "path") != 0)
            goto fail;
        return opts;
    }
    if (strstart(filename, "/dev/parport", NULL) ||
        strstart(filename, "/dev/ppi", NULL)) {
        qemu_opt_set(opts, "backend", "parport");
        qemu_opt_set(opts, "path", filename);
        return opts;
    }
    if (strstart(filename, "/dev/", NULL)) {
        qemu_opt_set(opts, "backend", "tty");
        qemu_opt_set(opts, "path", filename);
        return opts;
    }

fail:
    fprintf(stderr, "%s: fail on \"%s\"\n", __FUNCTION__, filename);
    qemu_opts_del(opts);
    return NULL;
}

static const struct {
    const char *name;
    CharDriverState *(*open)(QemuOpts *opts);
} backend_table[] = {
    { .name = "null",      .open = qemu_chr_open_null },
    { .name = "socket",    .open = qemu_chr_open_socket },
    { .name = "udp",       .open = qemu_chr_open_udp },
    { .name = "msmouse",   .open = qemu_chr_open_msmouse },
    { .name = "vc",        .open = text_console_init },
#ifdef _WIN32
    { .name = "file",      .open = qemu_chr_open_win_file_out },
    { .name = "pipe",      .open = qemu_chr_open_win_pipe },
    { .name = "console",   .open = qemu_chr_open_win_con },
    { .name = "serial",    .open = qemu_chr_open_win },
#else
    { .name = "file",      .open = qemu_chr_open_file_out },
    { .name = "pipe",      .open = qemu_chr_open_pipe },
    { .name = "pty",       .open = qemu_chr_open_pty },
    { .name = "stdio",     .open = qemu_chr_open_stdio },
#endif
#ifdef CONFIG_BRLAPI
    { .name = "braille",   .open = chr_baum_init },
#endif
#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
    || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
    { .name = "tty",       .open = qemu_chr_open_tty },
#endif
#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
    { .name = "parport",   .open = qemu_chr_open_pp },
#endif
};

CharDriverState *qemu_chr_open_opts(QemuOpts *opts,
                                    void (*init)(struct CharDriverState *s))
{
    CharDriverState *chr;
    int i;

    if (qemu_opts_id(opts) == NULL) {
        fprintf(stderr, "chardev: no id specified\n");
        return NULL;
    }

    for (i = 0; i < ARRAY_SIZE(backend_table); i++) {
        if (strcmp(backend_table[i].name, qemu_opt_get(opts, "backend")) == 0)
            break;
    }
    if (i == ARRAY_SIZE(backend_table)) {
        fprintf(stderr, "chardev: backend \"%s\" not found\n",
                qemu_opt_get(opts, "backend"));
        return NULL;
    }

    chr = backend_table[i].open(opts);
    if (!chr) {
        fprintf(stderr, "chardev: opening backend \"%s\" failed\n",
                qemu_opt_get(opts, "backend"));
        return NULL;
    }

    if (!chr->filename)
        chr->filename = qemu_strdup(qemu_opt_get(opts, "backend"));
    chr->init = init;
    QTAILQ_INSERT_TAIL(&chardevs, chr, next);

    if (qemu_opt_get_bool(opts, "mux", 0)) {
        CharDriverState *base = chr;
        int len = strlen(qemu_opts_id(opts)) + 6;
        base->label = qemu_malloc(len);
        snprintf(base->label, len, "%s-base", qemu_opts_id(opts));
        chr = qemu_chr_open_mux(base);
        chr->filename = base->filename;
        QTAILQ_INSERT_TAIL(&chardevs, chr, next);
    }
    chr->label = qemu_strdup(qemu_opts_id(opts));
    return chr;
}

CharDriverState *qemu_chr_open(const char *label, const char *filename, void (*init)(struct CharDriverState *s))
{
    const char *p;
    CharDriverState *chr;
    QemuOpts *opts;

    if (strstart(filename, "chardev:", &p)) {
        return qemu_chr_find(p);
    }

    opts = qemu_chr_parse_compat(label, filename);
    if (!opts)
        return NULL;

    chr = qemu_chr_open_opts(opts, init);
    if (chr && qemu_opt_get_bool(opts, "mux", 0)) {
        monitor_init(chr, MONITOR_USE_READLINE);
    }
    return chr;
}

void qemu_chr_close(CharDriverState *chr)
{
    QTAILQ_REMOVE(&chardevs, chr, next);
    if (chr->chr_close)
        chr->chr_close(chr);
    qemu_free(chr->filename);
    qemu_free(chr->label);
    qemu_free(chr);
}

void qemu_chr_info(Monitor *mon)
{
    CharDriverState *chr;

    QTAILQ_FOREACH(chr, &chardevs, next) {
        monitor_printf(mon, "%s: filename=%s\n", chr->label, chr->filename);
    }
}

CharDriverState *qemu_chr_find(const char *name)
{
    CharDriverState *chr;

    QTAILQ_FOREACH(chr, &chardevs, next) {
        if (strcmp(chr->label, name) != 0)
            continue;
        return chr;
    }
    return NULL;
}