+
+/* Terminate a string representing a filename at the final '/' to
+ * eliminate the final filename component, (leaving only the directory
+ * portions of the original path).
+ *
+ * Notes: A path containing no '/' character will not be modified.
+ * A path consisting only of "/" will not be modified.
+ */
+static void
+chop_trailing_path_component (char *path)
+{
+ char *slash;
+
+ slash = strrchr (path, '/');
+
+ if (slash == NULL)
+ return;
+
+ if (slash == path)
+ return;
+
+ *slash = '\0';
+}
+
+/* Find the absolute path of the currently executing binary.
+ *
+ * Returns: a string talloc'ed to 'ctx'
+ */
+static char *
+get_bin_name (void *ctx)
+{
+ const char *link = "/proc/self/exe";
+ char *name;
+
+ /* Yes, PATH_MAX is cheesy. I would have preferred to have
+ * used lstat and read the resulting st_size, but everytime I
+ * did that with /proc/self/exe I got a value of 0, (whereas
+ * with a "real" symbolic link I make myself I get the length
+ * of the filename being linked to). Go figure. */
+ int name_len = PATH_MAX + 1;
+
+ name = talloc_size (ctx, name_len);
+ if (name == NULL) {
+ fprintf (stderr, "Out of memory.\n");
+ exit (1);
+ }
+
+ name_len = readlink (link, name, name_len - 1);
+ if (name_len < 0) {
+ fprintf (stderr, "Failed to readlink %s: %s\n", link,
+ strerror (errno));
+ exit (1);
+ }
+
+ name[name_len] = '\0';
+
+ return name;
+}
+
+/* Does path exist? */
+static int
+exists (const char *path)
+{
+ struct stat st;
+ int err;
+
+ err = stat (path, &st);
+
+ /* Failed to stat. It either doesn't exist, or might as well not. */
+ if (err == -1)
+ return 0;
+
+ return 1;
+}
+
+/* Execute "program" in a pipe, reads its first line of output on
+ * stdout, and returns that as a string (discarding any further
+ * output).
+ *
+ * Returns NULL if the program failed to execute for any reason.
+ *
+ * NOTE: The caller should free() the returned string when done with
+ * it.
+ */
+static char *
+read_process_output_one_line (const char *program)
+{
+ FILE *process;
+ int status;
+ char *line = NULL;
+ size_t len = 0;
+ ssize_t bytes_read;
+
+ process = popen (program, "r");
+ if (process == NULL)
+ return NULL;
+
+ bytes_read = getline (&line, &len, process);
+
+ status = pclose (process);
+ if (! WIFEXITED (status))
+ return NULL;
+
+ if (WEXITSTATUS (status))
+ return NULL;
+
+ if (bytes_read == -1)
+ return NULL;
+
+ if (bytes_read) {
+ if (line[strlen(line)-1] == '\n')
+ line[strlen(line)-1] = '\0';
+ return line;
+ } else {
+ return NULL;
+ }
+}
+
+
+/* Look for "wrapper" library next to currently executing binary.
+ *
+ * If "wrapper" is an absolute path, return it directly.
+ *
+ * Otherwise, ("wrapper" is relative), look for an existing file named
+ * "wrapper" in the same directory as the currently executing binary,
+ * (as determined by /proc/self/exe). If that file exists, return its
+ * path.
+ *
+ * Otherwise, return the original, relative "wrapper".
+ */
+static const char *
+resolve_wrapper_path (void *ctx, const char *wrapper)
+{
+ char *bin_path, *lib_path;
+
+ if (*wrapper == '/')
+ return wrapper;
+
+ bin_path = get_bin_name (ctx);
+
+ chop_trailing_path_component (bin_path);
+
+ lib_path = talloc_asprintf (ctx, "%s/%s", bin_path, wrapper);
+
+ talloc_free (bin_path);
+
+ if (exists (lib_path))
+ return lib_path;
+
+ talloc_free (lib_path);
+
+ return wrapper;
+}
+
+/* Return path to directory containing Glaze wrapper's libGL.so.1
+ * suitable for use in LD_PRELOAD or LD_LIBRARY_PATH. Note that the
+ * path returned may not be a full path to the directory but may end
+ * with "$LIB" which will be expanded by the Linux dynamic linker to
+ * an architecture specific string (such as "lib/i386-linux-gnu" or
+ * "lib/x86_64-linux-gnu"). */
+static const char *
+find_glaze_libgl_dir (void)
+{
+ return CONFIG_LIBDIR "/glaze/$LIB";
+}
+
+void
+glaze_execute (int argc, char *argv[], const char *wrapper)
+{
+ void *ctx = talloc_new (NULL);
+ int i;
+
+ /* Set GLAZE_WRAPPER to absolute path of wrapper library */
+ if (wrapper == NULL || *wrapper == '\0') {
+ fprintf (stderr, "Error: glaze_execute called with empty wrapper library.\n");
+ return;
+ }
+
+ wrapper = resolve_wrapper_path (ctx, wrapper);
+
+ setenv ("GLAZE_WRAPPER", wrapper, 1);
+
+ /* Ensure GLAZE_LIBGL is set. If not, set GLAZE_LIBGL_32_AUTO
+ * and GLAZE_LIBGL_64_AUTO
+ *
+ * Note that we must do this before setting LD_LIBRARY_PATH,
+ * since after that, of course we would find Glaze's wrapper
+ * libGL.so.1. */
+ if (getenv ("GLAZE_LIBGL") == NULL) {
+ char *libgl_path;
+
+ libgl_path = read_process_output_one_line ("glaze-find-libgl-32");
+ if (libgl_path) {
+ setenv ("GLAZE_LIBGL_32_AUTO", libgl_path, 1);
+ free (libgl_path);
+ }
+
+ libgl_path = read_process_output_one_line ("glaze-find-libgl-64");
+ if (libgl_path) {
+ setenv ("GLAZE_LIBGL_64_AUTO", libgl_path, 1);
+ free (libgl_path);
+ }
+ }
+
+ /* Set LD_LIBRARY_PATH to include glaze's own libGL.so */
+ const char *glaze_libgl_dir, *ld_library_path;
+
+ glaze_libgl_dir = find_glaze_libgl_dir ();
+
+ ld_library_path = getenv ("LD_LIBRARY_PATH");
+
+ if (ld_library_path == NULL)
+ ld_library_path = glaze_libgl_dir;
+ else
+ ld_library_path = talloc_asprintf (ctx, "%s:%s",
+ glaze_libgl_dir,
+ ld_library_path);
+
+ setenv ("LD_LIBRARY_PATH", ld_library_path, 1);
+
+ talloc_free (ctx);
+
+ /* Execute program */
+ execvp (argv[0], argv);
+
+ /* If execvp returns, something went wrong. */
+ fprintf (stderr, "Error: Failed to exec:");
+ for (i = 0; i < argc; i++)
+ fprintf (stderr, " %s", argv[i]);
+ fprintf (stderr, "\n");
+
+ return;
+}
projects / glaze / commitdiff