[PATCH xserver] dri2: Pass a ScreenPtr through to the driver's AuthMagic function. (v3)

[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.

v2: Don't break ABI
v3: Paint the bikeshed blue; drop fd from AuthMagic2ProcPtr prototype

Cherry-picked from master, with the subsequent fixup commit sqashed in,
and modified to apply to the v6 DRI2InfoRec structure.

Signed-off-by: Christopher James Halse Rogers <christopher.halse.rogers at canonical.com>
---
 hw/xfree86/dri2/dri2.c |   50 ++++++++++++++++++++++++++++++++++++++++--------
 hw/xfree86/dri2/dri2.h |   11 +++++++++++
 2 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
index 591ff3a..b08618a 100644
--- a/hw/xfree86/dri2/dri2.c
+++ b/hw/xfree86/dri2/dri2.c
@@ -48,6 +48,8 @@
 
 #include "xf86.h"
 
+#include "xf86Priv.h"
+
 CARD8 dri2_major;               /* version of DRI2 supported by DDX */
 CARD8 dri2_minor;
 
@@ -104,7 +106,8 @@ typedef struct _DRI2Screen {
     DRI2ScheduleSwapProcPtr ScheduleSwap;
     DRI2GetMSCProcPtr GetMSC;
     DRI2ScheduleWaitMSCProcPtr ScheduleWaitMSC;
-    DRI2AuthMagicProcPtr AuthMagic;
+    DRI2AuthMagic2ProcPtr AuthMagic;
+    DRI2AuthMagicProcPtr LegacyAuthMagic;
     DRI2ReuseBufferNotifyProcPtr ReuseBufferNotify;
     DRI2SwapLimitValidateProcPtr SwapLimitValidate;
 
@@ -1109,12 +1112,22 @@ DRI2Connect(ScreenPtr pScreen, unsigned int driverType, int *fd,
     return TRUE;
 }
 
+static Bool
+DRI2AuthMagic (ScreenPtr pScreen, uint32_t magic)
+{
+    DRI2ScreenPtr ds = DRI2GetScreen(pScreen);
+    if (ds == NULL)
+        return -EINVAL;
+
+    return (*ds->LegacyAuthMagic) (ds->fd, magic);
+}
+
 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, magic))
         return FALSE;
 
     return TRUE;
@@ -1200,9 +1213,23 @@ DRI2ScreenInit(ScreenPtr pScreen, DRI2InfoPtr info)
     else {
         cur_minor = 1;
     }
-
+    
+    /* 
+     * Hack: Gate this on xorgWayland rather than info->version.
+     * This API is introduced in 1.13 with version 8, but we only support
+     * version 6. This allows us to upstream xwayland DDX support in a way
+     * that's source-compatible.
+     *
+     * If a driver is built without xwayland support, we'll die before we get
+     * here. If a driver is built with xwayland support, it'll support
+     * AuthMagic2, or crash; we don't care about xwayland ABI yet.
+     */
+    if (xorgWayland) {
+        ds->AuthMagic = info->AuthMagic2;
+    }
+    
     if (info->version >= 5) {
-        ds->AuthMagic = info->AuthMagic;
+        ds->LegacyAuthMagic = info->AuthMagic;
     }
 
     if (info->version >= 6) {
@@ -1212,14 +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 00b3668..cec9634 100644
--- a/hw/xfree86/dri2/dri2.h
+++ b/hw/xfree86/dri2/dri2.h
@@ -64,6 +64,7 @@ typedef void (*DRI2CopyRegionProcPtr) (DrawablePtr pDraw,
                                        DRI2BufferPtr pSrcBuffer);
 typedef void (*DRI2WaitProcPtr) (WindowPtr pWin, unsigned int sequence);
 typedef int (*DRI2AuthMagicProcPtr) (int fd, uint32_t magic);
+typedef int (*DRI2AuthMagic2ProcPtr) (ScreenPtr pScreen, uint32_t magic);
 
 /**
  * Schedule a buffer swap
@@ -211,6 +212,16 @@ typedef struct {
 
     DRI2ReuseBufferNotifyProcPtr ReuseBufferNotify;
     DRI2SwapLimitValidateProcPtr SwapLimitValidate;
+
+    /* added in version 8 AND in xwayland branch */
+    /* 
+     * MERGE NOTE: when merging xwayland to master, the commit adding this
+     * is unnecessary, but it's slightly different in master.
+     */
+    /* AuthMagic callback which passes extra context */
+    /* If this is NULL the AuthMagic callback is used */
+    /* If this is non-NULL the AuthMagic callback is ignored */
+    DRI2AuthMagic2ProcPtr AuthMagic2;
 } DRI2InfoRec, *DRI2InfoPtr;
 
 extern _X_EXPORT int DRI2EventBase;
-- 
1.7.10.4