Improve dynamic loading

Make loading code cleaner and prefix public
function names to allow static compilation.

1 files changed, 47 insertions, 34 deletions

diff --git a/src/disp.c b/src/disp.c
index c0294fe..8a1a174 100644
--- a/src/disp.c
+++ b/src/disp.c
@@ -25,17 +25,30 @@
 
 #include "disp.h"
 
-#define dlsym_and_check(dest, name)				\
-	dest->name = dlsym(dest->dl_handle, #name);		\
-	if ((!dest->name) || (dest->name == dest->dl_handle)) {	\
-		char *msg = dlerror();				\
-		fprintf(stderr, "calculer: %s\n", msg);		\
-		dlclose(dest->dl_handle);			\
-		free(dest);					\
-		return -1;					\
+static void *
+load_generic_symbol(struct disp *disp, char *base_name)
+{
+	char full_name[64] = {0};
+	void *ptr;
+
+	strcpy(full_name, disp->name);
+	strcat(full_name, "_");
+	strcat(full_name, base_name);
+
+	ptr = dlsym(disp->dl_handle, full_name);
+
+	if (!ptr)
+	{
+		fprintf(stderr, "calculer: %s\n", dlerror());
+		destroy_disp(disp);
+		exit(1);
 	}
 
-static int
+	return ptr;
+}
+
+
+static void
 load_symbols(struct disp *disp)
 {
 	void *handle = dlopen(disp->so_path, RTLD_LAZY);
@@ -43,24 +56,21 @@ load_symbols(struct disp *disp)
 	if (!handle)
 	{
 		fprintf(stderr, "calculer: %s\n", dlerror());
+		destroy_disp(disp);
 		exit(1);
 	}
 
-#ifndef NDEBUG
-	printf("INFO: successfully loaded symbols from \"%s\"\n", disp->so_path);
-#endif
+	disp->dl_handle	   = handle;
+	disp->init	   = load_generic_symbol(disp, "init");
+	disp->display_calc = load_generic_symbol(disp, "display_calc");
+	disp->read_input   = load_generic_symbol(disp, "read_input");
+	disp->display_res  = load_generic_symbol(disp, "display_res");
+	disp->destroy	   = load_generic_symbol(disp, "destroy");
+	disp->pre_reload   = load_generic_symbol(disp, "pre_reload");
+	disp->post_reload  = load_generic_symbol(disp, "post_reload");
 
-	disp->dl_handle = handle;
-	dlsym_and_check(disp, init);
-	dlsym_and_check(disp, display_calc);
-	dlsym_and_check(disp, read_input);
-	dlsym_and_check(disp, display_res);
-	dlsym_and_check(disp, destroy);
-#ifndef NDEBUG
-	dlsym_and_check(disp, pre_reload);
-	dlsym_and_check(disp, post_reload);
-#endif
-	return 0;
+	printf("INFO: successfully loaded symbols from \"%s\"\n",
+	       disp->so_path);
 }
 
 struct disp *
@@ -74,8 +84,11 @@ get_disp(char *disp_name)
 	strcat(so_path, ".so.0.0.0");
 	struct disp *disp = malloc(sizeof(*disp));
 	disp->so_path = strdup(so_path);
+	disp->name = disp_name;
+
+	load_symbols(disp);
 
-	return load_symbols(disp) == 0 ? disp : NULL;
+	return disp;
 #else
 #  error "not available yet"
 #endif
@@ -85,8 +98,12 @@ get_disp(char *disp_name)
 void
 destroy_disp(struct disp *disp)
 {
-	disp->destroy();
-	dlclose(disp->dl_handle);
+	if (disp->destroy)
+		disp->destroy();
+
+	if (disp->dl_handle)
+		dlclose(disp->dl_handle);
+
 	free(disp->so_path);
 	free(disp);
 }
@@ -95,22 +112,18 @@ destroy_disp(struct disp *disp)
 void
 disp_reload(struct disp *disp)
 {
-	int status;
 	printf("INFO: saving state\n");
 	void *state = disp->pre_reload();
+
 	printf("INFO: closing shared library\n");
 	dlclose(disp->dl_handle);
-	printf("INFO: reloading symbols\n");
-	status = load_symbols(disp);
 
-	if (status == -1)
-	{
-		printf("calculer: %s\n", dlerror());
-		exit(1);
-	}
+	printf("INFO: reloading symbols\n");
+	load_symbols(disp);
 
 	printf("INFO: loading state\n");
 	disp->post_reload(state);
+
 	printf("INFO: reloading done\n");
 }
 #endif