egl: add EGL_platform_device support

This new 'platform' is added by default with no guards.

It is effectively a copy of the surfaceless one, with updated function
names and brand new probe function.

Due to the reuse, some of the ifdef HAVE_SURFACELESS_PLATFORM guards
have been dropped.

A worthy mention are the changes in _egFindDisplay, since the original
and dup'd fd are required, we make use of the plat_opt argument.

Note that no hacks for eglGetDisplay are added - the API works only with
the eglGetPlatformDisplay* API.

v2:
 - s/_eglCompareDeviceDisplay/_eglSameDeviceDisplay/ (Eric)
 - let ^^ return bool (Eric)
 - fixup meson build, move files() further up (Eric)
 - copy from plat. surfaceless w/o the visual cleanups
 - close and free when destroying the dpy
 - sprinkle a few _eglDeviceSupports
 - split fd handling into separate function
 - use directly the render node if no FD is given (Mathias)

v3:
 - s/dpy/disp/g
 - drop swap_buffers* callbacks
 - drop loader_set_logger()
 - drop local define
 - re-introduce _eglGetDRMDeviceRenderNode()
 - EGL_WARN on ForceSoftware with HW device - continue using the HW device
 - bail out for "EGL_MESA_device_software" until it's fixed
 - wire-up the Android build

v4:
 - use new style _eglFindDisplay()
 - split hw vs sw code paths
 - don't close the internal fd (already handled in FiniDisplay())
 - make swrast work (bit hacky bit will do for now)
 - Android for real, drop autotools
 - Correct HW + LIBGL_ALWAYS_SOFTWARE check
 - use the dri2_create_drawable() helper

v5:
 - enhance comment around fd checks (Mathias)
 - rebase for dri2_init_surface() changes

Cc: Mathias Fröhlich <Mathias.Froehlich@gmx.net>
Acked-by: Marek Olšák <marek.olsak@amd.com> (v4)
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Signed-off-by: Marek Olšák <marek.olsak@amd.com>

src/egl/main/egldisplay.c

@@ -35,12 +35,14 @@
 #include <assert.h>
 #include <stdlib.h>
 #include <string.h>
+#include <fcntl.h>
 #include "c11/threads.h"
 #include "util/u_atomic.h"
 
 #include "eglcontext.h"
 #include "eglcurrent.h"
 #include "eglsurface.h"
+#include "egldevice.h"
 #include "egldisplay.h"
 #include "egldriver.h"
 #include "eglglobals.h"
@@ -202,6 +204,13 @@ _eglFiniDisplay(void)
          }
       }
 
+
+      /* The fcntl() code in _eglGetDeviceDisplay() ensures that valid fd >= 3,
+       * and invalid one is 0.
+       */
+      if (disp->Options.fd)
+         close(disp->Options.fd);
+
       free(disp->Options.Attribs);
       free(disp);
    }
@@ -557,3 +566,61 @@ _eglGetSurfacelessDisplay(void *native_display,
                           attrib_list);
 }
 #endif /* HAVE_SURFACELESS_PLATFORM */
+
+
+_EGLDisplay*
+_eglGetDeviceDisplay(void *native_display,
+                     const EGLAttrib *attrib_list)
+{
+   _EGLDevice *dev;
+   _EGLDisplay *display;
+   int fd = -1;
+
+   dev = _eglLookupDevice(native_display);
+   if (!dev) {
+      _eglError(EGL_BAD_PARAMETER, "eglGetPlatformDisplay");
+      return NULL;
+   }
+
+   if (attrib_list) {
+      for (int i = 0; attrib_list[i] != EGL_NONE; i += 2) {
+         EGLAttrib attrib = attrib_list[i];
+         EGLAttrib value = attrib_list[i + 1];
+
+         /* EGL_EXT_platform_device does not recognize any attributes,
+          * EGL_EXT_device_drm adds the optional EGL_DRM_MASTER_FD_EXT.
+          */
+
+         if (!_eglDeviceSupports(dev, _EGL_DEVICE_DRM) ||
+             attrib != EGL_DRM_MASTER_FD_EXT) {
+            _eglError(EGL_BAD_ATTRIBUTE, "eglGetPlatformDisplay");
+            return NULL;
+         }
+
+         fd = (int) value;
+      }
+   }
+
+   display = _eglFindDisplay(_EGL_PLATFORM_DEVICE, native_display, attrib_list);
+   if (!display) {
+      _eglError(EGL_BAD_ALLOC, "eglGetPlatformDisplay");
+      return NULL;
+   }
+
+   /* If the fd is explicitly provided and we did not dup() it yet, do so.
+    * The spec mandates that we do so, since we'll need it past the
+    * eglGetPlatformDispay call.
+    *
+    * The new fd is guaranteed to be 3 or greater.
+    */
+   if (fd != -1 && display->Options.fd == 0) {
+      display->Options.fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
+      if (display->Options.fd == -1) {
+         /* Do not (really) need to teardown the display */
+         _eglError(EGL_BAD_ALLOC, "eglGetPlatformDisplay");
+         return NULL;
+      }
+   }
+
+   return display;
+}