egldevice: copy udev dlopen code in from loader.c

This code is copied nearly verbatim from src/loader/loader.c. It
should be put somewhere so both files can reference the same code
without copy & pasting.

Signed-off-by: Jonny Lamb <jonny.lamb@collabora.co.uk>

1 files changed, 54 insertions, 0 deletions

diff --git a/src/egl/main/egldevice.c b/src/egl/main/egldevice.c
index c5c8e9433d..c79daff7fc 100644
--- a/src/egl/main/egldevice.c
+++ b/src/egl/main/egldevice.c
@@ -26,8 +26,14 @@
  **************************************************************************/
 
 
+#ifdef HAVE_LIBUDEV
+#include <dlfcn.h>
+#include <libudev.h>
+#endif
+
 #include "egldevice.h"
 #include "eglglobals.h"
+#include "egllog.h"
 #include "egltypedefs.h"
 
 
@@ -62,6 +68,54 @@ out:
    return info;
 }
 
+/* TODO: this is all copied from loader.c. it should probably be put somewhere
+ * common so both there and here can use the same source. also, if it remains
+ * here, it needs a mutex.*/
+#ifdef HAVE_LIBUDEV
+
+static void *udev_handle = NULL;
+
+static void *
+udev_dlopen_handle(void)
+{
+   if (!udev_handle) {
+      udev_handle = dlopen("libudev.so.1", RTLD_LOCAL | RTLD_LAZY);
+
+      if (!udev_handle) {
+         /* libudev.so.1 changed the return types of the two unref functions
+          * from voids to pointers.  We don't use those return values, and the
+          * only ABI I've heard that cares about this kind of change (calling
+          * a function with a void * return that actually only returns void)
+          * might be ia64.
+          */
+         udev_handle = dlopen("libudev.so.0", RTLD_LOCAL | RTLD_LAZY);
+
+         if (!udev_handle) {
+            _eglLog(_EGL_WARNING, "Couldn't dlopen libudev.so.1 or "
+                 "libudev.so.0, device detection may be broken.\n");
+         }
+      }
+   }
+
+   return udev_handle;
+}
+
+static int dlsym_failed = 0;
+
+static void *
+checked_dlsym(void *dlopen_handle, const char *name)
+{
+   void *result = dlsym(dlopen_handle, name);
+   if (!result)
+      dlsym_failed = 1;
+   return result;
+}
+
+#define UDEV_SYMBOL(ret, name, args) \
+   ret (*name) args = checked_dlsym(udev_dlopen_handle(), #name);
+
+#endif /* HAVE_LIBUDEV */
+
 /**
  * Finish device management.
  */