From f427658599546afd1fa19c31f25001ada8c0667d Mon Sep 17 00:00:00 2001
From: Carl Worth <cworth@cworth.org>
Date: Thu, 29 Aug 2013 15:25:09 -0700
Subject: [PATCH] Remove dependency of libglaze on libelf

The dependency is onerous since it requires the user of Glaze to have
both a 32-bit and 64-bit development version of libelf available, (and
also have a toolchain ready to find either one as appropriate).

Meanwhile, the only thing we were doing with libelf was determining
whether the current library targets a 32-bit or a 64-bit
architecture. But we are compiling this code twice, once for each
architecture. So it is actually quite simple to just conditionally
compile in the value we want.
---
 Makefile   |  4 ++--
 glaze-gl.c | 60 +++++-------------------------------------------------
 2 files changed, 7 insertions(+), 57 deletions(-)

diff --git a/Makefile b/Makefile
index 422d37f..48cb49e 100644
--- a/Makefile
+++ b/Makefile
@@ -45,11 +45,11 @@ $(LIBGLAZE_LIBNAME): glaze.c
 
 $(LIB64_DIR)/libGL.so.1: glaze-gl.c glapi.def
 	mkdir -p $(LIB64_DIR)
-	$(CC) $(GLAZE_CFLAGS) -m64 -fPIC -shared -Wl,-Bsymbolic -lelf -o $@ $<
+	$(CC) $(GLAZE_CFLAGS) -DGLAZE_BITS=64 -m64 -fPIC -shared -Wl,-Bsymbolic -o $@ $<
 
 $(LIB32_DIR)/libGL.so.1: glaze-gl.c specs/gl.def
 	mkdir -p $(LIB32_DIR)
-	$(CC) $(GLAZE_CFLAGS) -m32 -fPIC -shared -Wl,-Bsymbolic -lelf -o $@ $<
+	$(CC) $(GLAZE_CFLAGS) -DGLAZE_BITS=32 -m32 -fPIC -shared -Wl,-Bsymbolic -o $@ $<
 
 glaze-find-libgl-32: glaze-find-libgl.c
 	$(CC) $(GLAZE_CFLAGS) -m32 -fPIC -ldl -o $@ $<
diff --git a/glaze-gl.c b/glaze-gl.c
index d4ad33f..453d460 100644
--- a/glaze-gl.c
+++ b/glaze-gl.c
@@ -27,52 +27,10 @@
 #include <string.h>
 
 #include <fcntl.h>
-#include <gelf.h>
 
 void *libgl_handle;
 void *wrapper_handle;
 
-/* Is the given elf program 32 or 64 bit?
- *
- * Note: This function returns -1 if 'filename' cannot
- * be opened as a valid ELF file.
- */
-static int
-elf_bits (const char *filename)
-{
-	Elf *elf;
-	GElf_Ehdr ehdr;
-	int fd, class;
-
-	fd = open (filename, O_RDONLY, 0);
-	if (fd < 0)
-		return -1;
-
-	if (elf_version (EV_CURRENT ) == EV_NONE)
-		return -1;
-
-	elf = elf_begin (fd, ELF_C_READ, NULL);
-	if (elf == NULL)
-		return -1;
-
-	if (elf_kind (elf) != ELF_K_ELF)
-		return -1;
-
-	if (gelf_getehdr (elf, &ehdr) == NULL)
-		return -1;
-
-	class = gelf_getclass (elf);
-
-	switch (class) {
-	case ELFCLASS32:
-		return 32;
-	case ELFCLASS64:
-		return 64;
-	default:
-		return -1;
-	}
-}
-
 static void
 open_libgl_handle (void)
 {
@@ -84,20 +42,12 @@ open_libgl_handle (void)
 	libgl_path = getenv ("GLAZE_LIBGL");
 
 	if (libgl_path == NULL) {
-		Dl_info info;
-		int bits;
-
-		if (dladdr (open_libgl_handle, &info) == 0) {
-			fprintf (stderr, "Internal error: Failed to lookup filename of glaze library with dladdr.\n");
-			exit (1);
-		}
-
-		bits = elf_bits (info.dli_fname);
 
-		if (bits == 32)
-			libgl_path = getenv ("GLAZE_LIBGL_32_AUTO");
-		if (bits == 64)
-			libgl_path = getenv ("GLAZE_LIBGL_64_AUTO");
+#if GLAZE_BITS == 32
+		libgl_path = getenv ("GLAZE_LIBGL_32_AUTO");
+#elif GLAZE_BITS == 64
+		libgl_path = getenv ("GLAZE_LIBGL_64_AUTO");
+#endif
 
 		if (libgl_path == NULL) {
 			fprintf (stderr,
-- 
2.43.0