X-Git-Url: https://git.cworth.org/git?a=blobdiff_plain;f=glaze-gl.c;h=d4ad33f77023415466f76febc3ce5c62c8437f44;hb=fded9f20d5f5c92bd5af051117327816dda0238e;hp=b6e7d72d3f8f9317a4ae03136f73b1ff9f444fa7;hpb=2b7630a8f3277a568695fc59996c8bad34261454;p=glaze

diff --git a/glaze-gl.c b/glaze-gl.c
index b6e7d72..d4ad33f 100644
--- a/glaze-gl.c
+++ b/glaze-gl.c
@@ -24,27 +24,96 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#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)
 {
-	const char *path;
+	const char *libgl_path;
 
 	if (libgl_handle)
 		return;
 
-	path = getenv ("GLAZE_LIBGL");
-	if (path == NULL) {
-		fprintf (stderr, "GLAZE_LIBGL unset. Please set to path of real libGL.so under glaze.\n");
-		exit (1);
+	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 (libgl_path == NULL) {
+			fprintf (stderr,
+				 "Error: Failed to detect OpenGL library.\n"
+				 "Please set GLAZE_LIBGL to path of real libGL.so\n");
+			exit (1);
+		}
+
+		setenv ("GLAZE_LIBGL", libgl_path, 1);
 	}
 
-	libgl_handle = dlopen (path, RTLD_LAZY | RTLD_GLOBAL);
+	dlerror();
+	libgl_handle = dlopen (libgl_path, RTLD_LAZY | RTLD_GLOBAL);
 	if (libgl_handle == NULL) {
-		fprintf (stderr, "Error: Failed to dlopen %s\n", path);
+		fprintf (stderr, "glaze_init: Error: Failed to dlopen %s: %s\n",
+			 libgl_path, dlerror());
 		exit (1);
 	}
 }