[Qemu-devel] [PATCH 0/3] vnc patch collection

[Qemu-devel] [PATCH 0/3] vnc patch collection

[Gerd Hoffmann]

  Hi,

All of these patches have been on the list before, this is just a
re-post after rebasing them.  This time with a git repo to pull from
for your convinience.  Check the individual patch descriptions for
details.

cheers,
  Gerd

The following changes since commit 515689235c4c3d9c3f0406ddcdd21ed8da77062b:

  Merge remote-tracking branch 'spice/spice.v47' into staging (2012-01-19 12:51:02 -0600)

are available in the git repository at:

  git://git.kraxel.org/qemu vnc.1

Gerd Hoffmann (3):
      Fix vnc memory corruption with width = 1400
      vnc: fix ctrl key in vnc terminal emulation
      vnc: implement shared flag handling.

 qemu-options.hx |   13 ++++++
 ui/vnc.c        |  110 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 ui/vnc.h        |   16 ++++++++
 3 files changed, 136 insertions(+), 3 deletions(-)

[Qemu-devel] [PATCH 1/3] Fix vnc memory corruption with width = 1400

[Gerd Hoffmann]

vnc assumes that the screen width is a multiple of 16 in several places.
If this is not the case vnc will overrun buffers, corrupt memory, make
qemu crash.

This is the minimum fix for this bug. It makes sure we don't overrun the
scanline, thereby fixing the segfault.  The rendering is *not* correct
though, there is a black border at the right side of the screen, 8
pixels wide because 1400 % 16 == 8.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 ui/vnc.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/ui/vnc.c b/ui/vnc.c
index 16b79ec..5752bf8 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -2445,7 +2445,7 @@ 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;
-- 
1.7.1

[Qemu-devel] [PATCH 2/3] vnc: fix ctrl key in vnc terminal emulation

[Gerd Hoffmann]

Make the control keys for terminals on the vnc display
(i.e. qemu -vnc :0 -serial vc) work.  Makes the terminals
alot more usable as typing Ctrl-C in your serial console
actually has the desired effect ;)

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 ui/vnc.c |   10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/ui/vnc.c b/ui/vnc.c
index 5752bf8..810582b 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -1552,9 +1552,11 @@ 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 */
@@ -1642,7 +1644,11 @@ 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;
             }
         }
-- 
1.7.1

[Qemu-devel] [PATCH 3/3] vnc: implement shared flag handling.

[Gerd Hoffmann]

VNC clients send a shared flag in the client init message.  Up to now
qemu completely ignores this.  This patch implements shared flag
handling.  It comes with three policies:  By default qemu behaves as one
would expect:  Asking for a exclusive access grants exclusive access to
the client connecting.  There is also a desktop sharing mode which
disallows exclusive connects (so one forgetting -shared wouldn't drop
everybody else) and a compatibility mode which mimics the traditional
(but non-conforming) qemu behavior.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 qemu-options.hx |   13 +++++++
 ui/vnc.c        |   98 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ui/vnc.h        |   16 +++++++++
 3 files changed, 127 insertions(+), 0 deletions(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index 6295cde..6317660 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1090,6 +1090,19 @@ 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 810582b..83a9b15 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -47,6 +47,29 @@ static DisplayChangeListener *dcl;
 
 static int vnc_cursor_define(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,
                             socklen_t salen) {
@@ -997,6 +1020,7 @@ 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;
@@ -2054,8 +2078,67 @@ 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);
@@ -2562,6 +2645,7 @@ 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;
@@ -2755,6 +2839,7 @@ 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, ','))) {
@@ -2810,6 +2895,19 @@ 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 66689f1..0bd1fc6 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;
 
-- 
1.7.1