[PATCH] dri2: Pass a ScreenPtr through to the driver's AuthMagic

[Christopher James Halse Rogers]

xwayland drivers need access to their screen private data to authenticate.
Now that drivers no longer have direct access to the global screen arrays,
this needs to be passed in as function context. The way it was working
was ugly, anyway.

Signed-off-by: Christopher James Halse Rogers <christopher.halse.rogers at canonical.com>
---

This came up when I got around to fixing the nouveau xwayland patch review
comments; with things no longer meant to access the global xf86Screens array
the authmagic callback needed some other way to access driver private data.

Nouveau patch using this follows; I'll send it upstream once this gets
applied somewhere.

CCd to xorg-devel mainly for sanity review, but could be applied; as Airlied
has pointed out, there's no particular reason for the xwayland branch to
diverge on core infrastructure.


 hw/xfree86/dri2/dri2.c |   40 ++++++++++++++++++++++++++++++++++------
 hw/xfree86/dri2/dri2.h |    2 +-
 2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
index babf32f..0e79875 100644
--- a/hw/xfree86/dri2/dri2.c
+++ b/hw/xfree86/dri2/dri2.c
@@ -89,6 +89,8 @@ typedef struct _DRI2Drawable {
     Bool needInvalidate;
 } DRI2DrawableRec, *DRI2DrawablePtr;
 
+typedef int (*DRI2LegacyAuthMagicProcPtr) (int fd, uint32_t magic);
+
 typedef struct _DRI2Screen {
     ScreenPtr screen;
     int refcnt;
@@ -105,6 +107,7 @@ typedef struct _DRI2Screen {
     DRI2GetMSCProcPtr GetMSC;
     DRI2ScheduleWaitMSCProcPtr ScheduleWaitMSC;
     DRI2AuthMagicProcPtr AuthMagic;
+    DRI2LegacyAuthMagicProcPtr LegacyAuthMagic;
     DRI2ReuseBufferNotifyProcPtr ReuseBufferNotify;
     DRI2SwapLimitValidateProcPtr SwapLimitValidate;
     DRI2GetParamProcPtr GetParam;
@@ -1110,12 +1113,22 @@ DRI2Connect(ScreenPtr pScreen, unsigned int driverType, int *fd,
     return TRUE;
 }
 
+static Bool
+DRI2AuthMagic (ScreenPtr pScreen, int fd, uint32_t magic)
+{
+    DRI2ScreenPtr ds = DRI2GetScreen(pScreen);
+    if (ds == NULL || (*ds->LegacyAuthMagic) (ds->fd, magic))
+        return FALSE;
+
+    return TRUE;
+}
+
 Bool
 DRI2Authenticate(ScreenPtr pScreen, uint32_t magic)
 {
     DRI2ScreenPtr ds = DRI2GetScreen(pScreen);
 
-    if (ds == NULL || (*ds->AuthMagic) (ds->fd, magic))
+    if (ds == NULL || (*ds->AuthMagic) (pScreen, ds->fd, magic))
         return FALSE;
 
     return TRUE;
@@ -1202,9 +1215,17 @@ DRI2ScreenInit(ScreenPtr pScreen, DRI2InfoPtr info)
         cur_minor = 1;
     }
 
-    if (info->version >= 5) {
+    if (info->version >= 7) {
         ds->AuthMagic = info->AuthMagic;
     }
+    else if (info->version >= 5) {
+        /*
+         * This cast is safe; if the driver has provided a V5 or V6 InfoRec
+         * then AuthMagic is of type DRI2LegacyAuthMagicProcPtr, and the C
+         * standard guarantees that we can typecast it back and call it.
+         */
+        ds->LegacyAuthMagic = (DRI2LegacyAuthMagicProcPtr)info->AuthMagic;
+    }
 
     if (info->version >= 6) {
         ds->ReuseBufferNotify = info->ReuseBufferNotify;
@@ -1218,14 +1239,21 @@ DRI2ScreenInit(ScreenPtr pScreen, DRI2InfoPtr info)
 
     /*
      * if the driver doesn't provide an AuthMagic function or the info struct
-     * version is too low, it relies on the old method (using libdrm) or fail
+     * version is too low, call through LegacyAuthMagic
      */
-    if (!ds->AuthMagic)
+    if (!ds->AuthMagic) {
+        ds->AuthMagic = DRI2AuthMagic;
+        /*
+         * If the driver doesn't provide an AuthMagic function
+         * it relies on the old method (using libdrm) or fails
+         */
+        if (!ds->LegacyAuthMagic)
 #ifdef WITH_LIBDRM
-        ds->AuthMagic = drmAuthMagic;
+            ds->LegacyAuthMagic = drmAuthMagic;
 #else
-        goto err_out;
+            goto err_out;
 #endif
+    }
 
     /* Initialize minor if needed and set to minimum provied by DDX */
     if (!dri2_minor || dri2_minor > cur_minor)
diff --git a/hw/xfree86/dri2/dri2.h b/hw/xfree86/dri2/dri2.h
index f849be6..90886a9 100644
--- a/hw/xfree86/dri2/dri2.h
+++ b/hw/xfree86/dri2/dri2.h
@@ -63,7 +63,7 @@ typedef void (*DRI2CopyRegionProcPtr) (DrawablePtr pDraw,
                                        DRI2BufferPtr pDestBuffer,
                                        DRI2BufferPtr pSrcBuffer);
 typedef void (*DRI2WaitProcPtr) (WindowPtr pWin, unsigned int sequence);
-typedef int (*DRI2AuthMagicProcPtr) (int fd, uint32_t magic);
+typedef int (*DRI2AuthMagicProcPtr) (ScreenPtr pScreen, int fd, uint32_t magic);
 
 /**
  * Schedule a buffer swap
-- 
1.7.10.4