loader: Factor out the common driver opening logic from each loader.

I copied the code from egl_dri2.c, but the functionality was equivalent
between all the loaders other than their particular environment variables.

v2: Drop the logging function equivalent to loader_default_logger()
    (requested by Eric, Emil).  Move the SCons workaround across.  Drop
    the now-unused driGetDriverExtensions() declaration that was lost in a
    rebase.

Reviewed-by: Eric Engestrom <[email protected]> (v1)
Reviewed-by: Emil Velikov <[email protected]> (v1)

3 files changed, 8 insertions, 73 deletions

diff --git a/src/egl/Makefile.am b/src/egl/Makefile.am
index 24a8e96a8e1..7269912d96f 100644
--- a/src/egl/Makefile.am
+++ b/src/egl/Makefile.am
@@ -119,8 +119,7 @@ AM_CFLAGS += \
 	-I$(top_srcdir)/src/egl/drivers/dri2 \
 	-I$(top_srcdir)/src/gbm/backends/dri \
 	-I$(top_builddir)/src/egl/wayland/wayland-drm \
-	-I$(top_srcdir)/src/egl/wayland/wayland-drm \
-	-DDEFAULT_DRIVER_DIR=\"$(DRI_DRIVER_SEARCH_DIR)\"
+	-I$(top_srcdir)/src/egl/wayland/wayland-drm
 
 nodist_libEGL_common_la_SOURCES = \
 	$(dri2_backend_GENERATED_FILES)
diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
index af2b3a6fa8f..0be9235835d 100644
--- a/src/egl/drivers/dri2/egl_dri2.c
+++ b/src/egl/drivers/dri2/egl_dri2.c
@@ -483,75 +483,14 @@ static const __DRIextension **
 dri2_open_driver(_EGLDisplay *disp)
 {
    struct dri2_egl_display *dri2_dpy = dri2_egl_display(disp);
-   const __DRIextension **extensions = NULL;
-   char path[PATH_MAX], *search_paths, *next, *end;
-   char *get_extensions_name;
-   const __DRIextension **(*get_extensions)(void);
-
-   search_paths = NULL;
-   if (geteuid() == getuid()) {
-      /* don't allow setuid apps to use LIBGL_DRIVERS_PATH */
-      search_paths = getenv("LIBGL_DRIVERS_PATH");
-   }
-   if (search_paths == NULL)
-      search_paths = DEFAULT_DRIVER_DIR;
-
-   dri2_dpy->driver = NULL;
-   end = search_paths + strlen(search_paths);
-   for (char *p = search_paths; p < end; p = next + 1) {
-      int len;
-      next = strchr(p, ':');
-      if (next == NULL)
-         next = end;
-
-      len = next - p;
-#if GLX_USE_TLS
-      snprintf(path, sizeof path,
-               "%.*s/tls/%s_dri.so", len, p, dri2_dpy->driver_name);
-      dri2_dpy->driver = dlopen(path, RTLD_NOW | RTLD_GLOBAL);
-#endif
-      if (dri2_dpy->driver == NULL) {
-         snprintf(path, sizeof path,
-                  "%.*s/%s_dri.so", len, p, dri2_dpy->driver_name);
-         dri2_dpy->driver = dlopen(path, RTLD_NOW | RTLD_GLOBAL);
-         if (dri2_dpy->driver == NULL)
-            _eglLog(_EGL_DEBUG, "failed to open %s: %s\n", path, dlerror());
-      }
-      /* not need continue to loop all paths once the driver is found */
-      if (dri2_dpy->driver != NULL)
-         break;
-   }
-
-   if (dri2_dpy->driver == NULL) {
-      _eglLog(_EGL_WARNING,
-              "DRI2: failed to open %s (search paths %s)",
-              dri2_dpy->driver_name, search_paths);
-      return NULL;
-   }
-
-   _eglLog(_EGL_DEBUG, "DRI2: dlopen(%s)", path);
-
-   get_extensions_name = loader_get_extensions_name(dri2_dpy->driver_name);
-   if (get_extensions_name) {
-      get_extensions = dlsym(dri2_dpy->driver, get_extensions_name);
-      if (get_extensions) {
-         extensions = get_extensions();
-      } else {
-         _eglLog(_EGL_DEBUG, "driver does not expose %s(): %s\n",
-                 get_extensions_name, dlerror());
-      }
-      free(get_extensions_name);
-   }
-
-   if (!extensions)
-      extensions = dlsym(dri2_dpy->driver, __DRI_DRIVER_EXTENSIONS);
-   if (extensions == NULL) {
-      _eglLog(_EGL_WARNING,
-              "DRI2: driver exports no extensions (%s)", dlerror());
-      dlclose(dri2_dpy->driver);
-   }
+   static const char *search_path_vars[] = {
+      "LIBGL_DRIVERS_PATH",
+      NULL,
+   };
 
-   return extensions;
+   return loader_open_driver(dri2_dpy->driver_name,
+                             &dri2_dpy->driver,
+                             search_path_vars);
 }
 
 EGLBoolean
diff --git a/src/egl/meson.build b/src/egl/meson.build
index 8c0ffea8b40..372842967d3 100644
--- a/src/egl/meson.build
+++ b/src/egl/meson.build
@@ -93,9 +93,6 @@ if with_dri2
     'drivers/dri2/egl_dri2.h',
     'drivers/dri2/egl_dri2_fallbacks.h',
   )
-  c_args_for_egl += [
-    '-DDEFAULT_DRIVER_DIR="@0@"'.format(dri_search_path),
-  ]
 
   if with_platform_x11
     files_egl += files('drivers/dri2/platform_x11.c')