[FFmpeg-cvslog] xcbgrab: Do not assume the non shm image data is always available

[Luca Barbato]

ffmpeg | branch: release/2.6 | Luca Barbato <lu_zero at gentoo.org> | Sat Mar 14 12:30:10 2015 +0100| [4a46a29b07c41630c0e5eb68747feabed7607fd0] | committer: Michael Niedermayer

xcbgrab: Do not assume the non shm image data is always available

Signed-off-by: Luca Barbato <lu_zero at gentoo.org>
(cherry picked from commit 82a10225f817b2612fdd2b23af9d4f0a3408df3b)

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4a46a29b07c41630c0e5eb68747feabed7607fd0
---

 libavdevice/xcbgrab.c |   16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/libavdevice/xcbgrab.c b/libavdevice/xcbgrab.c
index 477eed7..c141c36 100644
--- a/libavdevice/xcbgrab.c
+++ b/libavdevice/xcbgrab.c
@@ -149,13 +149,25 @@ static int xcbgrab_frame(AVFormatContext *s, AVPacket *pkt)
     xcb_get_image_cookie_t iq;
     xcb_get_image_reply_t *img;
     xcb_drawable_t drawable = c->screen->root;
+    xcb_generic_error_t *e = NULL;
     uint8_t *data;
     int length, ret;
 
     iq  = xcb_get_image(c->conn, XCB_IMAGE_FORMAT_Z_PIXMAP, drawable,
                         c->x, c->y, c->width, c->height, ~0);
 
-    img = xcb_get_image_reply(c->conn, iq, NULL);
+    img = xcb_get_image_reply(c->conn, iq, &e);
+
+    if (e) {
+        av_log(s, AV_LOG_ERROR,
+               "Cannot get the image data "
+               "event_error: response_type:%u error_code:%u "
+               "sequence:%u resource_id:%u minor_code:%u major_code:%u.\n",
+               e->response_type, e->error_code,
+               e->sequence, e->resource_id, e->minor_code, e->major_code);
+        return AVERROR(EACCES);
+    }
+
     if (!img)
         return AVERROR(EAGAIN);
 
@@ -409,7 +421,7 @@ static int xcbgrab_read_packet(AVFormatContext *s, AVPacket *pkt)
         ret = xcbgrab_frame(s, pkt);
 
 #if CONFIG_LIBXCB_XFIXES
-    if (c->draw_mouse && p->same_screen)
+    if (ret >= 0 && c->draw_mouse && p->same_screen)
         xcbgrab_draw_mouse(s, pkt, p, geo);
 #endif