Archipelago » qemu

/*

 * 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 "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 <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 _BSD

#include <sys/stat.h>

#ifdef __FreeBSD__

#include <libutil.h>

#include <dev/ppbus/ppi.h>

#include <dev/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 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) {

        s->bh = qemu_bh_new(qemu_chr_reset_bh, s);

        qemu_bh_schedule(s->bh);

    }

}

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);

}

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(void)

{

    CharDriverState *chr;

    chr = qemu_mallocz(sizeof(CharDriverState));

    if (!chr)

        return NULL;

    chr->chr_write = null_chr_write;

    return chr;

}

/* MUX driver for serial I/O splitting */

static int term_timestamps;

static int64_t term_timestamps_start;

#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;

    unsigned char buffer[MUX_BUFFER_SIZE];

    int prod;

    int cons;

    int mux_cnt;

    int term_got_escape;

    int max_size;

} MuxDriver;

static int mux_chr_write(CharDriverState *chr, const uint8_t *buf, int len)

{

    MuxDriver *d = chr->opaque;

    int ret;

    if (!term_timestamps) {

        ret = d->drv->chr_write(d->drv, buf, len);

    } else {

        int i;

        ret = 0;

        for(i = 0; i < len; i++) {

            ret += d->drv->chr_write(d->drv, buf+i, 1);

            if (buf[i] == '\n') {

                char buf1[64];

                int64_t ti;

                int secs;

                ti = qemu_get_clock(rt_clock);

                if (term_timestamps_start == -1)

                    term_timestamps_start = ti;

                ti -= term_timestamps_start;

                secs = ti / 1000000000;

                snprintf(buf1, sizeof(buf1),

                         "[%02d:%02d:%02d.%03d] ",

                         secs / 3600,

                         (secs / 60) % 60,

                         secs % 60,

                         (int)((ti / 1000000) % 1000));

                d->drv->chr_write(d->drv, (uint8_t *)buf1, strlen(buf1));

            }

        }

    }

    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 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':

            {

                int i;

                for (i = 0; i < nb_drives; i++) {

                        bdrv_commit(drives_table[i].bdrv);

                }

            }

            break;

        case 'b':

            qemu_chr_event(chr, CHR_EVENT_BREAK);

            break;

        case 'c':

            /* Switch to the next registered device */

            chr->focus++;

            if (chr->focus >= d->mux_cnt)

                chr->focus = 0;

            break;

       case 't':

           term_timestamps = !term_timestamps;

           term_timestamps_start = -1;

           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)

{

    int m = chr->focus;

    MuxDriver *d = chr->opaque;

    while (d->prod != d->cons &&

           d->chr_can_read[m] &&

           d->chr_can_read[m](d->ext_opaque[m])) {

        d->chr_read[m](d->ext_opaque[m],

                       &d->buffer[d->cons++ & MUX_BUFFER_MASK], 1);

    }

}

static int mux_chr_can_read(void *opaque)

{

    CharDriverState *chr = opaque;

    MuxDriver *d = chr->opaque;

    if ((d->prod - d->cons) < MUX_BUFFER_SIZE)

        return 1;

    if (d->chr_can_read[chr->focus])

        return d->chr_can_read[chr->focus](d->ext_opaque[chr->focus]);

    return 0;

}

static void mux_chr_read(void *opaque, const uint8_t *buf, int size)

{

    CharDriverState *chr = opaque;

    MuxDriver *d = chr->opaque;

    int m = chr->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 == d->cons &&

                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[d->prod++ & 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++)

        if (d->chr_event[i])

            d->chr_event[i](d->ext_opaque[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);

    }

    chr->focus = d->mux_cnt;

    d->mux_cnt++;

}

static CharDriverState *qemu_chr_open_mux(CharDriverState *drv)

{

    CharDriverState *chr;

    MuxDriver *d;

    chr = qemu_mallocz(sizeof(CharDriverState));

    if (!chr)

        return NULL;

    d = qemu_mallocz(sizeof(MuxDriver));

    if (!d) {

        free(chr);

        return NULL;

    }

    chr->opaque = d;

    d->drv = drv;

    chr->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);

        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 (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 (nographic && s->fd_in == 0) {

        } else {

            qemu_set_fd_handler2(s->fd_in, NULL, NULL, NULL, NULL);

        }

    }

    qemu_free(s);

}

/* 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));

    if (!chr)

        return NULL;

    s = qemu_mallocz(sizeof(FDCharDriver));

    if (!s) {

        free(chr);

        return NULL;

    }

    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(const char *file_out)

{

    int fd_out;

    TFR(fd_out = open(file_out, 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(const char *filename)

{

    int fd_in, fd_out;

    char filename_in[256], filename_out[256];

    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);

        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 (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(void)

{

    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. */

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;

}

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__)

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)