Archipelago » qemu

/*

 * QEMU VNC display driver

 *

 * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>

 * Copyright (C) 2006 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 "console.h"

#include "sysemu.h"

#include "qemu_socket.h"

#include "qemu-timer.h"

#include "audio/audio.h"

#define VNC_REFRESH_INTERVAL (1000 / 30)

#include "vnc_keysym.h"

#include "keymaps.c"

#include "d3des.h"

#ifdef CONFIG_VNC_TLS

#include <gnutls/gnutls.h>

#include <gnutls/x509.h>

#endif /* CONFIG_VNC_TLS */

// #define _VNC_DEBUG 1

#ifdef _VNC_DEBUG

#define VNC_DEBUG(fmt, ...) do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)

#if CONFIG_VNC_TLS && _VNC_DEBUG >= 2

/* Very verbose, so only enabled for _VNC_DEBUG >= 2 */

static void vnc_debug_gnutls_log(int level, const char* str) {

    VNC_DEBUG("%d %s", level, str);

}

#endif /* CONFIG_VNC_TLS && _VNC_DEBUG */

#else

#define VNC_DEBUG(fmt, ...) do { } while (0)

#endif

typedef struct Buffer

{

    size_t capacity;

    size_t offset;

    uint8_t *buffer;

} Buffer;

typedef struct VncState VncState;

typedef int VncReadEvent(VncState *vs, uint8_t *data, size_t len);

typedef void VncWritePixels(VncState *vs, void *data, int size);

typedef void VncSendHextileTile(VncState *vs,

                                int x, int y, int w, int h,

                                void *last_bg,

                                void *last_fg,

                                int *has_bg, int *has_fg);

#define VNC_MAX_WIDTH 2048

#define VNC_MAX_HEIGHT 2048

#define VNC_DIRTY_WORDS (VNC_MAX_WIDTH / (16 * 32))

#define VNC_AUTH_CHALLENGE_SIZE 16

enum {

    VNC_AUTH_INVALID = 0,

    VNC_AUTH_NONE = 1,

    VNC_AUTH_VNC = 2,

    VNC_AUTH_RA2 = 5,

    VNC_AUTH_RA2NE = 6,

    VNC_AUTH_TIGHT = 16,

    VNC_AUTH_ULTRA = 17,

    VNC_AUTH_TLS = 18,

    VNC_AUTH_VENCRYPT = 19

};

#ifdef CONFIG_VNC_TLS

enum {

    VNC_WIREMODE_CLEAR,

    VNC_WIREMODE_TLS,

};

enum {

    VNC_AUTH_VENCRYPT_PLAIN = 256,

    VNC_AUTH_VENCRYPT_TLSNONE = 257,

    VNC_AUTH_VENCRYPT_TLSVNC = 258,

    VNC_AUTH_VENCRYPT_TLSPLAIN = 259,

    VNC_AUTH_VENCRYPT_X509NONE = 260,

    VNC_AUTH_VENCRYPT_X509VNC = 261,

    VNC_AUTH_VENCRYPT_X509PLAIN = 262,

};

#define X509_CA_CERT_FILE "ca-cert.pem"

#define X509_CA_CRL_FILE "ca-crl.pem"

#define X509_SERVER_KEY_FILE "server-key.pem"

#define X509_SERVER_CERT_FILE "server-cert.pem"

#endif /* CONFIG_VNC_TLS */

struct VncState

{

    QEMUTimer *timer;

    int lsock;

    int csock;

    DisplayState *ds;

    int need_update;

    int width;

    int height;

    uint32_t dirty_row[VNC_MAX_HEIGHT][VNC_DIRTY_WORDS];

    char *old_data;

    int depth; /* internal VNC frame buffer byte per pixel */

    int has_resize;

    int has_hextile;

    int has_pointer_type_change;

    int has_WMVi;

    int absolute;

    int last_x;

    int last_y;

    int major;

    int minor;

    char *display;

    char *password;

    int auth;

#ifdef CONFIG_VNC_TLS

    int subauth;

    int x509verify;

    char *x509cacert;

    char *x509cacrl;

    char *x509cert;

    char *x509key;

#endif

    char challenge[VNC_AUTH_CHALLENGE_SIZE];

#ifdef CONFIG_VNC_TLS

    int wiremode;

    gnutls_session_t tls_session;

#endif

    Buffer output;

    Buffer input;

    kbd_layout_t *kbd_layout;

    /* current output mode information */

    VncWritePixels *write_pixels;

    VncSendHextileTile *send_hextile_tile;

    int pix_bpp, pix_big_endian;

    int client_red_shift, client_red_max, server_red_shift, server_red_max;

    int client_green_shift, client_green_max, server_green_shift, server_green_max;

    int client_blue_shift, client_blue_max, server_blue_shift, server_blue_max;

    CaptureVoiceOut *audio_cap;

    struct audsettings as;

    VncReadEvent *read_handler;

    size_t read_handler_expect;

    /* input */

    uint8_t modifiers_state[256];

};

static VncState *vnc_state; /* needed for info vnc */

void do_info_vnc(void)

{

    if (vnc_state == NULL || vnc_state->display == NULL)

        term_printf("VNC server disabled\n");

    else {

        term_printf("VNC server active on: ");

        term_print_filename(vnc_state->display);

        term_printf("\n");

        if (vnc_state->csock == -1)

            term_printf("No client connected\n");

        else

            term_printf("Client connected\n");

    }

}

/* TODO

   1) Get the queue working for IO.

   2) there is some weirdness when using the -S option (the screen is grey

      and not totally invalidated

   3) resolutions > 1024

*/

static void vnc_write(VncState *vs, const void *data, size_t len);

static void vnc_write_u32(VncState *vs, uint32_t value);

static void vnc_write_s32(VncState *vs, int32_t value);

static void vnc_write_u16(VncState *vs, uint16_t value);

static void vnc_write_u8(VncState *vs, uint8_t value);

static void vnc_flush(VncState *vs);

static void vnc_update_client(void *opaque);

static void vnc_client_read(void *opaque);

static void vnc_colordepth(DisplayState *ds, int depth);

static inline void vnc_set_bit(uint32_t *d, int k)

{

    d[k >> 5] |= 1 << (k & 0x1f);

}

static inline void vnc_clear_bit(uint32_t *d, int k)

{

    d[k >> 5] &= ~(1 << (k & 0x1f));

}

static inline void vnc_set_bits(uint32_t *d, int n, int nb_words)

{

    int j;

    j = 0;

    while (n >= 32) {

        d[j++] = -1;

        n -= 32;

    }

    if (n > 0)

        d[j++] = (1 << n) - 1;

    while (j < nb_words)

        d[j++] = 0;

}

static inline int vnc_get_bit(const uint32_t *d, int k)

{

    return (d[k >> 5] >> (k & 0x1f)) & 1;

}

static inline int vnc_and_bits(const uint32_t *d1, const uint32_t *d2,

                               int nb_words)

{

    int i;

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

        if ((d1[i] & d2[i]) != 0)

            return 1;

    }

    return 0;

}

static void vnc_dpy_update(DisplayState *ds, int x, int y, int w, int h)

{

    VncState *vs = ds->opaque;

    int i;

    h += y;

    /* round x down to ensure the loop only spans one 16-pixel block per,

       iteration.  otherwise, if (x % 16) != 0, the last iteration may span

       two 16-pixel blocks but we only mark the first as dirty

    */

    w += (x % 16);

    x -= (x % 16);

    x = MIN(x, vs->width);

    y = MIN(y, vs->height);

    w = MIN(x + w, vs->width) - x;

    h = MIN(h, vs->height);

    for (; y < h; y++)

        for (i = 0; i < w; i += 16)

            vnc_set_bit(vs->dirty_row[y], (x + i) / 16);

}

static void vnc_framebuffer_update(VncState *vs, int x, int y, int w, int h,

                                   int32_t encoding)

{

    vnc_write_u16(vs, x);

    vnc_write_u16(vs, y);

    vnc_write_u16(vs, w);

    vnc_write_u16(vs, h);

    vnc_write_s32(vs, encoding);

}

static void vnc_dpy_resize(DisplayState *ds, int w, int h)

{

    int size_changed;

    VncState *vs = ds->opaque;

    ds->data = qemu_realloc(ds->data, w * h * vs->depth);

    vs->old_data = qemu_realloc(vs->old_data, w * h * vs->depth);

    if (ds->data == NULL || vs->old_data == NULL) {

        fprintf(stderr, "vnc: memory allocation failed\n");

        exit(1);

    }

    if (ds->depth != vs->depth * 8) {

        ds->depth = vs->depth * 8;

        console_color_init(ds);

    }

    size_changed = ds->width != w || ds->height != h;

    ds->width = w;

    ds->height = h;

    ds->linesize = w * vs->depth;

    if (size_changed) {

        vs->width = ds->width;

        vs->height = ds->height;

        if (vs->csock != -1 && vs->has_resize) {

            vnc_write_u8(vs, 0);  /* msg id */

            vnc_write_u8(vs, 0);

            vnc_write_u16(vs, 1); /* number of rects */

            vnc_framebuffer_update(vs, 0, 0, ds->width, ds->height, -223);

            vnc_flush(vs);

        }

    }

    memset(vs->dirty_row, 0xFF, sizeof(vs->dirty_row));

    memset(vs->old_data, 42, ds_get_linesize(vs->ds) * ds_get_height(vs->ds));

}

/* fastest code */

static void vnc_write_pixels_copy(VncState *vs, void *pixels, int size)

{

    vnc_write(vs, pixels, size);

}

/* slowest but generic code. */

static void vnc_convert_pixel(VncState *vs, uint8_t *buf, uint32_t v)

{

    uint8_t r, g, b;

    r = ((v >> vs->server_red_shift) & vs->server_red_max) * (vs->client_red_max + 1) /

        (vs->server_red_max + 1);

    g = ((v >> vs->server_green_shift) & vs->server_green_max) * (vs->client_green_max + 1) /

        (vs->server_green_max + 1);

    b = ((v >> vs->server_blue_shift) & vs->server_blue_max) * (vs->client_blue_max + 1) /

        (vs->server_blue_max + 1);

    v = (r << vs->client_red_shift) |

        (g << vs->client_green_shift) |

        (b << vs->client_blue_shift);

    switch(vs->pix_bpp) {

    case 1:

        buf[0] = v;

        break;

    case 2:

        if (vs->pix_big_endian) {

            buf[0] = v >> 8;

            buf[1] = v;

        } else {

            buf[1] = v >> 8;

            buf[0] = v;

        }

        break;

    default:

    case 4:

        if (vs->pix_big_endian) {

            buf[0] = v >> 24;

            buf[1] = v >> 16;

            buf[2] = v >> 8;

            buf[3] = v;

        } else {

            buf[3] = v >> 24;

            buf[2] = v >> 16;

            buf[1] = v >> 8;

            buf[0] = v;

        }

        break;

    }

}

static void vnc_write_pixels_generic(VncState *vs, void *pixels1, int size)

{

    uint8_t buf[4];

    if (vs->depth == 4) {

        uint32_t *pixels = pixels1;

        int n, i;

        n = size >> 2;

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

            vnc_convert_pixel(vs, buf, pixels[i]);

            vnc_write(vs, buf, vs->pix_bpp);

        }

    } else if (vs->depth == 2) {

        uint16_t *pixels = pixels1;

        int n, i;

        n = size >> 1;

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

            vnc_convert_pixel(vs, buf, pixels[i]);

            vnc_write(vs, buf, vs->pix_bpp);

        }

    } else if (vs->depth == 1) {

        uint8_t *pixels = pixels1;

        int n, i;

        n = size;

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

            vnc_convert_pixel(vs, buf, pixels[i]);

            vnc_write(vs, buf, vs->pix_bpp);

        }

    } else {

        fprintf(stderr, "vnc_write_pixels_generic: VncState color depth not supported\n");

    }

}

static void send_framebuffer_update_raw(VncState *vs, int x, int y, int w, int h)

{

    int i;

    uint8_t *row;

    vnc_framebuffer_update(vs, x, y, w, h, 0);

    row = ds_get_data(vs->ds) + y * ds_get_linesize(vs->ds) + x * vs->depth;

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

        vs->write_pixels(vs, row, w * vs->depth);

        row += ds_get_linesize(vs->ds);

    }

}

static void hextile_enc_cord(uint8_t *ptr, int x, int y, int w, int h)

{

    ptr[0] = ((x & 0x0F) << 4) | (y & 0x0F);

    ptr[1] = (((w - 1) & 0x0F) << 4) | ((h - 1) & 0x0F);

}

#define BPP 8

#include "vnchextile.h"

#undef BPP

#define BPP 16

#include "vnchextile.h"

#undef BPP

#define BPP 32

#include "vnchextile.h"

#undef BPP

#define GENERIC

#define BPP 8

#include "vnchextile.h"

#undef BPP

#undef GENERIC

#define GENERIC

#define BPP 16

#include "vnchextile.h"

#undef BPP

#undef GENERIC

#define GENERIC

#define BPP 32

#include "vnchextile.h"

#undef BPP

#undef GENERIC

static void send_framebuffer_update_hextile(VncState *vs, int x, int y, int w, int h)

{

    int i, j;

    int has_fg, has_bg;

    uint8_t *last_fg, *last_bg;

    vnc_framebuffer_update(vs, x, y, w, h, 5);

    last_fg = (uint8_t *) malloc(vs->depth);

    last_bg = (uint8_t *) malloc(vs->depth);

    has_fg = has_bg = 0;

    for (j = y; j < (y + h); j += 16) {

        for (i = x; i < (x + w); i += 16) {

            vs->send_hextile_tile(vs, i, j,

                                  MIN(16, x + w - i), MIN(16, y + h - j),

                                  last_bg, last_fg, &has_bg, &has_fg);

        }

    }

    free(last_fg);

    free(last_bg);

}

static void send_framebuffer_update(VncState *vs, int x, int y, int w, int h)

{

        if (vs->has_hextile)

            send_framebuffer_update_hextile(vs, x, y, w, h);

        else

            send_framebuffer_update_raw(vs, x, y, w, h);

}

static void vnc_copy(DisplayState *ds, int src_x, int src_y, int dst_x, int dst_y, int w, int h)

{

    int src, dst;

    uint8_t *src_row;

    uint8_t *dst_row;

    char *old_row;

    int y = 0;

    int pitch = ds_get_linesize(ds);

    VncState *vs = ds->opaque;

    vnc_update_client(vs);

    if (dst_y > src_y) {

        y = h - 1;

        pitch = -pitch;

    }

    src = (ds_get_linesize(ds) * (src_y + y) + vs->depth * src_x);

    dst = (ds_get_linesize(ds) * (dst_y + y) + vs->depth * dst_x);

    src_row = ds_get_data(ds) + src;

    dst_row = ds_get_data(ds) + dst;

    old_row = vs->old_data + dst;

    for (y = 0; y < h; y++) {

        memmove(old_row, src_row, w * vs->depth);

        memmove(dst_row, src_row, w * vs->depth);

        src_row += pitch;

        dst_row += pitch;

        old_row += pitch;

    }

    vnc_write_u8(vs, 0);  /* msg id */

    vnc_write_u8(vs, 0);

    vnc_write_u16(vs, 1); /* number of rects */

    vnc_framebuffer_update(vs, dst_x, dst_y, w, h, 1);

    vnc_write_u16(vs, src_x);

    vnc_write_u16(vs, src_y);

    vnc_flush(vs);

}

static int find_dirty_height(VncState *vs, int y, int last_x, int x)

{

    int h;

    for (h = 1; h < (vs->height - y); h++) {

        int tmp_x;

        if (!vnc_get_bit(vs->dirty_row[y + h], last_x))

            break;

        for (tmp_x = last_x; tmp_x < x; tmp_x++)

            vnc_clear_bit(vs->dirty_row[y + h], tmp_x);

    }

    return h;

}

static void vnc_update_client(void *opaque)

{

    VncState *vs = opaque;

    if (vs->need_update && vs->csock != -1) {

        int y;

        uint8_t *row;

        char *old_row;

        uint32_t width_mask[VNC_DIRTY_WORDS];

        int n_rectangles;

        int saved_offset;

        int has_dirty = 0;

        vga_hw_update();

        vnc_set_bits(width_mask, (vs->width / 16), VNC_DIRTY_WORDS);

        /* Walk through the dirty map and eliminate tiles that

           really aren't dirty */

        row = ds_get_data(vs->ds);

        old_row = vs->old_data;

        for (y = 0; y < vs->height; y++) {

            if (vnc_and_bits(vs->dirty_row[y], width_mask, VNC_DIRTY_WORDS)) {

                int x;

                uint8_t *ptr;

                char *old_ptr;

                ptr = row;

                old_ptr = (char*)old_row;

                for (x = 0; x < ds_get_width(vs->ds); x += 16) {

                    if (memcmp(old_ptr, ptr, 16 * vs->depth) == 0) {

                        vnc_clear_bit(vs->dirty_row[y], (x / 16));

                    } else {

                        has_dirty = 1;

                        memcpy(old_ptr, ptr, 16 * vs->depth);

                    }

                    ptr += 16 * vs->depth;

                    old_ptr += 16 * vs->depth;

                }

            }

            row += ds_get_linesize(vs->ds);

            old_row += ds_get_linesize(vs->ds);

        }

        if (!has_dirty && !vs->audio_cap) {

            qemu_mod_timer(vs->timer, qemu_get_clock(rt_clock) + VNC_REFRESH_INTERVAL);

            return;

        }

        /* Count rectangles */

        n_rectangles = 0;

        vnc_write_u8(vs, 0);  /* msg id */

        vnc_write_u8(vs, 0);

        saved_offset = vs->output.offset;

        vnc_write_u16(vs, 0);

        for (y = 0; y < vs->height; y++) {

            int x;

            int last_x = -1;

            for (x = 0; x < vs->width / 16; x++) {

                if (vnc_get_bit(vs->dirty_row[y], x)) {

                    if (last_x == -1) {

                        last_x = x;

                    }

                    vnc_clear_bit(vs->dirty_row[y], x);

                } else {

                    if (last_x != -1) {

                        int h = find_dirty_height(vs, y, last_x, x);

                        send_framebuffer_update(vs, last_x * 16, y, (x - last_x) * 16, h);

                        n_rectangles++;

                    }

                    last_x = -1;

                }

            }

            if (last_x != -1) {

                int h = find_dirty_height(vs, y, last_x, x);

                send_framebuffer_update(vs, last_x * 16, y, (x - last_x) * 16, h);

                n_rectangles++;

            }

        }

        vs->output.buffer[saved_offset] = (n_rectangles >> 8) & 0xFF;

        vs->output.buffer[saved_offset + 1] = n_rectangles & 0xFF;

        vnc_flush(vs);

    }

    if (vs->csock != -1) {

        qemu_mod_timer(vs->timer, qemu_get_clock(rt_clock) + VNC_REFRESH_INTERVAL);

    }

}

static int vnc_listen_poll(void *opaque)

{

    VncState *vs = opaque;

    if (vs->csock == -1)

        return 1;

    return 0;

}

static void buffer_reserve(Buffer *buffer, size_t len)

{

    if ((buffer->capacity - buffer->offset) < len) {

        buffer->capacity += (len + 1024);

        buffer->buffer = qemu_realloc(buffer->buffer, buffer->capacity);

        if (buffer->buffer == NULL) {

            fprintf(stderr, "vnc: out of memory\n");

            exit(1);

        }

    }

}

static int buffer_empty(Buffer *buffer)

{

    return buffer->offset == 0;

}

static uint8_t *buffer_end(Buffer *buffer)

{

    return buffer->buffer + buffer->offset;

}

static void buffer_reset(Buffer *buffer)

{

        buffer->offset = 0;

}

static void buffer_append(Buffer *buffer, const void *data, size_t len)

{

    memcpy(buffer->buffer + buffer->offset, data, len);

    buffer->offset += len;

}

/* audio */

static void audio_capture_notify(void *opaque, audcnotification_e cmd)

{

    VncState *vs = opaque;

    switch (cmd) {

    case AUD_CNOTIFY_DISABLE:

        vnc_write_u8(vs, 255);

        vnc_write_u8(vs, 1);

        vnc_write_u16(vs, 0);

        vnc_flush(vs);

        break;

    case AUD_CNOTIFY_ENABLE:

        vnc_write_u8(vs, 255);

        vnc_write_u8(vs, 1);

        vnc_write_u16(vs, 1);

        vnc_flush(vs);

        break;

    }

}

static void audio_capture_destroy(void *opaque)

{

}

static void audio_capture(void *opaque, void *buf, int size)

{

    VncState *vs = opaque;

    vnc_write_u8(vs, 255);

    vnc_write_u8(vs, 1);

    vnc_write_u16(vs, 2);

    vnc_write_u32(vs, size);

    vnc_write(vs, buf, size);

    vnc_flush(vs);

}

static void audio_add(VncState *vs)

{

    struct audio_capture_ops ops;

    if (vs->audio_cap) {

        term_printf ("audio already running\n");

        return;

    }

    ops.notify = audio_capture_notify;

    ops.destroy = audio_capture_destroy;

    ops.capture = audio_capture;

    vs->audio_cap = AUD_add_capture(NULL, &vs->as, &ops, vs);

    if (!vs->audio_cap) {

        term_printf ("Failed to add audio capture\n");

    }

}

static void audio_del(VncState *vs)

{

    if (vs->audio_cap) {

        AUD_del_capture(vs->audio_cap, vs);

        vs->audio_cap = NULL;

    }

}

static int vnc_client_io_error(VncState *vs, int ret, int last_errno)

{

    if (ret == 0 || ret == -1) {

        if (ret == -1) {

            switch (last_errno) {

                case EINTR:

                case EAGAIN:

#ifdef _WIN32

                case WSAEWOULDBLOCK:

#endif

                    return 0;

                default:

                    break;

            }

        }

        VNC_DEBUG("Closing down client sock %d %d\n", ret, ret < 0 ? last_errno : 0);

        qemu_set_fd_handler2(vs->csock, NULL, NULL, NULL, NULL);

        closesocket(vs->csock);

        vs->csock = -1;

        vs->ds->idle = 1;

        buffer_reset(&vs->input);

        buffer_reset(&vs->output);

        vs->need_update = 0;

#ifdef CONFIG_VNC_TLS

        if (vs->tls_session) {

            gnutls_deinit(vs->tls_session);

            vs->tls_session = NULL;

        }

        vs->wiremode = VNC_WIREMODE_CLEAR;

#endif /* CONFIG_VNC_TLS */

        audio_del(vs);

        return 0;

    }

    return ret;

}

static void vnc_client_error(VncState *vs)

{

    vnc_client_io_error(vs, -1, EINVAL);

}

static void vnc_client_write(void *opaque)

{

    long ret;

    VncState *vs = opaque;

#ifdef CONFIG_VNC_TLS

    if (vs->tls_session) {

        ret = gnutls_write(vs->tls_session, vs->output.buffer, vs->output.offset);

        if (ret < 0) {

            if (ret == GNUTLS_E_AGAIN)

                errno = EAGAIN;

            else

                errno = EIO;

            ret = -1;

        }

    } else

#endif /* CONFIG_VNC_TLS */

        ret = send(vs->csock, vs->output.buffer, vs->output.offset, 0);

    ret = vnc_client_io_error(vs, ret, socket_error());

    if (!ret)

        return;

    memmove(vs->output.buffer, vs->output.buffer + ret, (vs->output.offset - ret));

    vs->output.offset -= ret;

    if (vs->output.offset == 0) {

        qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs);

    }

}

static void vnc_read_when(VncState *vs, VncReadEvent *func, size_t expecting)

{

    vs->read_handler = func;

    vs->read_handler_expect = expecting;

}

static void vnc_client_read(void *opaque)

{

    VncState *vs = opaque;

    long ret;

    buffer_reserve(&vs->input, 4096);

#ifdef CONFIG_VNC_TLS

    if (vs->tls_session) {

        ret = gnutls_read(vs->tls_session, buffer_end(&vs->input), 4096);

        if (ret < 0) {

            if (ret == GNUTLS_E_AGAIN)

                errno = EAGAIN;

            else

                errno = EIO;

            ret = -1;

        }

    } else

#endif /* CONFIG_VNC_TLS */

        ret = recv(vs->csock, buffer_end(&vs->input), 4096, 0);

    ret = vnc_client_io_error(vs, ret, socket_error());

    if (!ret)

        return;

    vs->input.offset += ret;

    while (vs->read_handler && vs->input.offset >= vs->read_handler_expect) {

        size_t len = vs->read_handler_expect;

        int ret;

        ret = vs->read_handler(vs, vs->input.buffer, len);

        if (vs->csock == -1)

            return;

        if (!ret) {

            memmove(vs->input.buffer, vs->input.buffer + len, (vs->input.offset - len));

            vs->input.offset -= len;

        } else {

            vs->read_handler_expect = ret;

        }

    }

}

static void vnc_write(VncState *vs, const void *data, size_t len)

{

    buffer_reserve(&vs->output, len);

    if (buffer_empty(&vs->output)) {

        qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, vnc_client_write, vs);

    }

    buffer_append(&vs->output, data, len);

}

static void vnc_write_s32(VncState *vs, int32_t value)

{

    vnc_write_u32(vs, *(uint32_t *)&value);

}