Merge remote-tracking branch 'kraxel/vnc.2' into staging

* kraxel/vnc.2:
  vnc: lift modifier keys on client disconnect.
  vnc: implement shared flag handling.
  vnc: fix ctrl key in vnc terminal emulation
  Fix vnc memory corruption with width = 1400

3 files changed, 161 insertions, 3 deletions

diff --git a/qemu-options.hx b/qemu-options.hx
index 42d22aebf9..51369c45b1 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1095,6 +1095,19 @@ This can be really helpful to save bandwidth when playing videos. Disabling
 adaptive encodings allows to restore the original static behavior of encodings
 like Tight.
 
+@item share=[allow-exclusive|force-shared|ignore]
+
+Set display sharing policy.  'allow-exclusive' allows clients to ask
+for exclusive access.  As suggested by the rfb spec this is
+implemented by dropping other connections.  Connecting multiple
+clients in parallel requires all clients asking for a shared session
+(vncviewer: -shared switch).  This is the default.  'force-shared'
+disables exclusive client access.  Useful for shared desktop sessions,
+where you don't want someone forgetting specify -shared disconnect
+everybody else.  'ignore' completely ignores the shared flag and
+allows everybody connect unconditionally.  Doesn't conform to the rfb
+spec but is traditional qemu behavior.
+
 @end table
 ETEXI
 
diff --git a/ui/vnc.c b/ui/vnc.c
index 16b79ec423..02b71bcd2c 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -46,6 +46,30 @@ static VncDisplay *vnc_display; /* needed for info vnc */
 static DisplayChangeListener *dcl;
 
 static int vnc_cursor_define(VncState *vs);
+static void vnc_release_modifiers(VncState *vs);
+
+static void vnc_set_share_mode(VncState *vs, VncShareMode mode)
+{
+#ifdef _VNC_DEBUG
+    static const char *mn[] = {
+        [0]                           = "undefined",
+        [VNC_SHARE_MODE_CONNECTING]   = "connecting",
+        [VNC_SHARE_MODE_SHARED]       = "shared",
+        [VNC_SHARE_MODE_EXCLUSIVE]    = "exclusive",
+        [VNC_SHARE_MODE_DISCONNECTED] = "disconnected",
+    };
+    fprintf(stderr, "%s/%d: %s -> %s\n", __func__,
+            vs->csock, mn[vs->share_mode], mn[mode]);
+#endif
+
+    if (vs->share_mode == VNC_SHARE_MODE_EXCLUSIVE) {
+        vs->vd->num_exclusive--;
+    }
+    vs->share_mode = mode;
+    if (vs->share_mode == VNC_SHARE_MODE_EXCLUSIVE) {
+        vs->vd->num_exclusive++;
+    }
+}
 
 static char *addr_to_string(const char *format,
                             struct sockaddr_storage *sa,
@@ -997,6 +1021,7 @@ static void vnc_disconnect_start(VncState *vs)
 {
     if (vs->csock == -1)
         return;
+    vnc_set_share_mode(vs, VNC_SHARE_MODE_DISCONNECTED);
     qemu_set_fd_handler2(vs->csock, NULL, NULL, NULL, NULL);
     closesocket(vs->csock);
     vs->csock = -1;
@@ -1027,6 +1052,7 @@ static void vnc_disconnect_finish(VncState *vs)
     vnc_sasl_client_cleanup(vs);
 #endif /* CONFIG_VNC_SASL */
     audio_del(vs);
+    vnc_release_modifiers(vs);
 
     QTAILQ_REMOVE(&vs->vd->clients, vs, next);
 
@@ -1552,9 +1578,11 @@ static void do_key_event(VncState *vs, int down, int keycode, int sym)
         else
             kbd_put_keycode(keycode | SCANCODE_UP);
     } else {
+        bool numlock = vs->modifiers_state[0x45];
+        bool control = (vs->modifiers_state[0x1d] ||
+                        vs->modifiers_state[0x9d]);
         /* QEMU console emulation */
         if (down) {
-            int numlock = vs->modifiers_state[0x45];
             switch (keycode) {
             case 0x2a:                          /* Left Shift */
             case 0x36:                          /* Right Shift */
@@ -1642,13 +1670,40 @@ static void do_key_event(VncState *vs, int down, int keycode, int sym)
                 break;
 
             default:
-                kbd_put_keysym(sym);
+                if (control) {
+                    kbd_put_keysym(sym & 0x1f);
+                } else {
+                    kbd_put_keysym(sym);
+                }
                 break;
             }
         }
     }
 }
 
+static void vnc_release_modifiers(VncState *vs)
+{
+    static const int keycodes[] = {
+        /* shift, control, alt keys, both left & right */
+        0x2a, 0x36, 0x1d, 0x9d, 0x38, 0xb8,
+    };
+    int i, keycode;
+
+    if (!is_graphic_console()) {
+        return;
+    }
+    for (i = 0; i < ARRAY_SIZE(keycodes); i++) {
+        keycode = keycodes[i];
+        if (!vs->modifiers_state[keycode]) {
+            continue;
+        }
+        if (keycode & SCANCODE_GREY) {
+            kbd_put_keycode(SCANCODE_EMUL0);
+        }
+        kbd_put_keycode(keycode | SCANCODE_UP);
+    }
+}
+
 static void key_event(VncState *vs, int down, uint32_t sym)
 {
     int keycode;
@@ -2048,8 +2103,67 @@ static int protocol_client_msg(VncState *vs, uint8_t *data, size_t len)
 static int protocol_client_init(VncState *vs, uint8_t *data, size_t len)
 {
     char buf[1024];
+    VncShareMode mode;
     int size;
 
+    mode = data[0] ? VNC_SHARE_MODE_SHARED : VNC_SHARE_MODE_EXCLUSIVE;
+    switch (vs->vd->share_policy) {
+    case VNC_SHARE_POLICY_IGNORE:
+        /*
+         * Ignore the shared flag.  Nothing to do here.
+         *
+         * Doesn't conform to the rfb spec but is traditional qemu
+         * behavior, thus left here as option for compatibility
+         * reasons.
+         */
+        break;
+    case VNC_SHARE_POLICY_ALLOW_EXCLUSIVE:
+        /*
+         * Policy: Allow clients ask for exclusive access.
+         *
+         * Implementation: When a client asks for exclusive access,
+         * disconnect all others. Shared connects are allowed as long
+         * as no exclusive connection exists.
+         *
+         * This is how the rfb spec suggests to handle the shared flag.
+         */
+        if (mode == VNC_SHARE_MODE_EXCLUSIVE) {
+            VncState *client;
+            QTAILQ_FOREACH(client, &vs->vd->clients, next) {
+                if (vs == client) {
+                    continue;
+                }
+                if (client->share_mode != VNC_SHARE_MODE_EXCLUSIVE &&
+                    client->share_mode != VNC_SHARE_MODE_SHARED) {
+                    continue;
+                }
+                vnc_disconnect_start(client);
+            }
+        }
+        if (mode == VNC_SHARE_MODE_SHARED) {
+            if (vs->vd->num_exclusive > 0) {
+                vnc_disconnect_start(vs);
+                return 0;
+            }
+        }
+        break;
+    case VNC_SHARE_POLICY_FORCE_SHARED:
+        /*
+         * Policy: Shared connects only.
+         * Implementation: Disallow clients asking for exclusive access.
+         *
+         * Useful for shared desktop sessions where you don't want
+         * someone forgetting to say -shared when running the vnc
+         * client disconnect everybody else.
+         */
+        if (mode == VNC_SHARE_MODE_EXCLUSIVE) {
+            vnc_disconnect_start(vs);
+            return 0;
+        }
+        break;
+    }
+    vnc_set_share_mode(vs, mode);
+
     vs->client_width = ds_get_width(vs->ds);
     vs->client_height = ds_get_height(vs->ds);
     vnc_write_u16(vs, vs->client_width);
@@ -2445,7 +2559,7 @@ static int vnc_refresh_server_surface(VncDisplay *vd)
             guest_ptr  = guest_row;
             server_ptr = server_row;
 
-            for (x = 0; x < vd->guest.ds->width;
+            for (x = 0; x + 15 < vd->guest.ds->width;
                     x += 16, guest_ptr += cmp_bytes, server_ptr += cmp_bytes) {
                 if (!test_and_clear_bit((x / 16), vd->guest.dirty[y]))
                     continue;
@@ -2556,6 +2670,7 @@ static void vnc_connect(VncDisplay *vd, int csock, int skipauth)
 
     vnc_client_cache_addr(vs);
     vnc_qmp_event(vs, QEVENT_VNC_CONNECTED);
+    vnc_set_share_mode(vs, VNC_SHARE_MODE_CONNECTING);
 
     vs->vd = vd;
     vs->ds = vd->ds;
@@ -2749,6 +2864,7 @@ int vnc_display_open(DisplayState *ds, const char *display)
 
     if (!(vs->display = strdup(display)))
         return -1;
+    vs->share_policy = VNC_SHARE_POLICY_ALLOW_EXCLUSIVE;
 
     options = display;
     while ((options = strchr(options, ','))) {
@@ -2804,6 +2920,19 @@ int vnc_display_open(DisplayState *ds, const char *display)
             vs->lossy = true;
         } else if (strncmp(options, "non-adapative", 13) == 0) {
             vs->non_adaptive = true;
+        } else if (strncmp(options, "share=", 6) == 0) {
+            if (strncmp(options+6, "ignore", 6) == 0) {
+                vs->share_policy = VNC_SHARE_POLICY_IGNORE;
+            } else if (strncmp(options+6, "allow-exclusive", 15) == 0) {
+                vs->share_policy = VNC_SHARE_POLICY_ALLOW_EXCLUSIVE;
+            } else if (strncmp(options+6, "force-shared", 12) == 0) {
+                vs->share_policy = VNC_SHARE_POLICY_FORCE_SHARED;
+            } else {
+                fprintf(stderr, "unknown vnc share= option\n");
+                g_free(vs->display);
+                vs->display = NULL;
+                return -1;
+            }
         }
     }
 
diff --git a/ui/vnc.h b/ui/vnc.h
index 66689f1d60..0bd1fc6d23 100644
--- a/ui/vnc.h
+++ b/ui/vnc.h
@@ -122,9 +122,24 @@ struct VncSurface
     DisplaySurface *ds;
 };
 
+typedef enum VncShareMode {
+    VNC_SHARE_MODE_CONNECTING = 1,
+    VNC_SHARE_MODE_SHARED,
+    VNC_SHARE_MODE_EXCLUSIVE,
+    VNC_SHARE_MODE_DISCONNECTED,
+} VncShareMode;
+
+typedef enum VncSharePolicy {
+    VNC_SHARE_POLICY_IGNORE = 1,
+    VNC_SHARE_POLICY_ALLOW_EXCLUSIVE,
+    VNC_SHARE_POLICY_FORCE_SHARED,
+} VncSharePolicy;
+
 struct VncDisplay
 {
     QTAILQ_HEAD(, VncState) clients;
+    int num_exclusive;
+    VncSharePolicy share_policy;
     QEMUTimer *timer;
     int timer_interval;
     int lsock;
@@ -250,6 +265,7 @@ struct VncState
     int last_y;
     int client_width;
     int client_height;
+    VncShareMode share_mode;
 
     uint32_t vnc_encoding;