vfs_gpu: offer 'vfs_gpu_env' call

* retrieve Genode::Env from plugin, this way no mesa applications need to
  be changed.
* add 'vfs_gpu' api
* remove when all required functionality is implemented within the plugin.

issue #4380

repos/gems/lib/import/import-vfs_gpu.mk

@@ -0,0 +1 @@
+REP_INC_DIR += src/lib/vfs/gpu

repos/gems/lib/symbols/vfs_gpu

@@ -0,0 +1,3 @@
+_Z11vfs_gpu_envv T
+_Z18vfs_gpu_connectionm T
+vfs_file_system_factory T

repos/gems/recipes/api/vfs_gpu/content.mk

@@ -0,0 +1,13 @@
+MIRROR_FROM_REP_DIR := \
+	src/lib/vfs/gpu/vfs_gpu.h \
+	lib/import/import-vfs_gpu.mk \
+	lib/symbols/vfs_gpu
+
+content: $(MIRROR_FROM_REP_DIR)
+
+$(MIRROR_FROM_REP_DIR):
+	$(mirror_from_rep_dir)
+
+LICENSE:
+	cp $(GENODE_DIR)/LICENSE $@
+

repos/gems/recipes/api/vfs_gpu/hash

@@ -0,0 +1 @@
+2022-01-14-b 717f2b436a763c3ac1a752ae3fa9b194c786f1a9

repos/gems/recipes/src/vfs_gpu/api

@@ -0,0 +1 @@
+vfs_gpu

repos/gems/src/lib/vfs/gpu/vfs.cc

@@ -21,6 +21,8 @@
 #include <util/xml_generator.h>
 #include <vfs/single_file_system.h>
 
+#include "vfs_gpu.h"
+
 namespace Vfs_gpu
 {
 	using namespace Vfs;
@@ -135,10 +137,9 @@ struct Vfs_gpu::File_system : Single_file_system
 
 static Vfs_gpu::File_system *_fs { nullptr };
 
-
 /**
  * XXX: return GPU session for given ID, retrieved by 'stat->inode'.
- * This function is used, for example, by libdrm via (dlopen/dlsym).
+ * This function is used, for example, by libdrm
  */
 Gpu::Connection *vfs_gpu_connection(unsigned long id)
 {
@@ -149,15 +150,25 @@ Gpu::Connection *vfs_gpu_connection(unsigned long id)
 
 	try {
 		return _fs->_handle_space.apply<Gpu_vfs_handle>(
-		         Id_space::Id { .value = id },
+			Id_space::Id { .value = id },
-		         [] (Gpu_vfs_handle &handle) {
+			[] (Gpu_vfs_handle &handle)
-		         return &handle._gpu_session; });
+			{
+				return &handle._gpu_session;
+			}
+		);
 	} catch (...) { }
 
 	return nullptr;
 }
 
 
+static Vfs::Env *_env { nullptr };
+
+Genode::Env *vfs_gpu_env()
+{
+	return _env ? &_env->env() : nullptr;
+}
+
 /**************************
  ** VFS plugin interface **
  **************************/
@@ -169,6 +180,7 @@ extern "C" Vfs::File_system_factory *vfs_file_system_factory(void)
 		Vfs::File_system *create(Vfs::Env &vfs_env,
 		                         Genode::Xml_node node) override
 		{
+			_env = &vfs_env;
 			try {
 				_fs = new (vfs_env.alloc()) Vfs_gpu::File_system(vfs_env, node);
 				return _fs;

repos/gems/src/lib/vfs/gpu/vfs_gpu.h

@@ -0,0 +1,29 @@
+/*
+ * \brief  Public interface for libdrm
+ * \author Sebastian Sumpf
+ * \date   2022-01-14
+ *
+ * This is a interim solution becaues libdrm currently needs access to the
+ * GPU::Connection and Genode::Env. Once all the necessary features are provided
+ * by this plugin this interface is removed.
+ */
+
+/*
+ * Copyright (C) 2022 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU Affero General Public License version 3.
+ */
+
+#ifndef _VFS_GPU_H_
+#define _VFS_GPU_H_
+
+namespace Gpu { class Connection; }
+
+Gpu::Connection *vfs_gpu_connection(unsigned long);
+
+namespace Genode { class Env; }
+
+Genode::Env *vfs_gpu_env();
+
+#endif /* _VFS_GPU_H_ */