WIP: Add a COB_LOAD_GLOBAL config option to modify dlopen behavior

ChangeLog

@@ -1,3 +1,12 @@
+2025-01-08  Simon Sobisch <[email protected]>
+
+	* config/runtime.cfg: Add documentation for COB_LOAD_GLOBAL flag
+
+2025-01-08  Florian Schmidt <[email protected]>
+
+	* libcob/call.c, libcob/coblocal.h, libcob/common.c: Introduce a flag
+	  COB_LOAD_GLOBAL (load_global) to toggle if the symbols of CALLed 
+	  programs should be made available in the global namespace 
 
 2024-12-08  Simon Sobisch <[email protected]>
 

config/runtime.cfg

@@ -306,6 +306,18 @@
 #          Default:  false
 #          Example:  PHYSICAL_CANCEL  TRUE
 
+# Environment name:  COB_LOAD_GLOBAL
+#   Parameter name:  load_global
+#          Purpose:  tell the system loader to provide symbols in CALLed
+#                    programs globally, allowing symbols to be found for linked
+#                    libraries later
+#             Type:  boolean
+#             Note:  COBOL CALLs will always find symbols in already CALLed or
+#                    pre-modules; this setting is mostly an advise to the system,
+#                    not all systems are capable of loading libraries global/local
+#          Default:  false
+#          Example:  load_global true
+
 #
 ## File I/O
 #

libcob/call.c

@@ -60,65 +60,82 @@ FILE *fmemopen (void *buf, size_t size, const char *mode);
 	https://wiki.musl-libc.org/functional-differences-from-glibc.html#Unloading_libraries
 */
 
+static cob_settings		*cobsetptr = NULL;
+
 #ifdef	_WIN32
+	#define WIN32_LEAN_AND_MEAN
+	#include <windows.h>
+	#include <io.h>	/* for access */
 
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#include <io.h>	/* for access */
+	static void *
+	lt_dlsym (HMODULE hmod, const char *p)
+	{
+		union {
+			FARPROC		modaddr;
+			void		*voidptr;
+		} modun;
 
-static HMODULE
-lt_dlopen (const char *x)
-{
-	if (x == NULL) {
-		return GetModuleHandle (NULL);
+		modun.modaddr = GetProcAddress(hmod, p);
+		return modun.voidptr;
 	}
-	return LoadLibrary(x);
-}
-
-static void *
-lt_dlsym (HMODULE hmod, const char *p)
-{
-	union {
-		FARPROC		modaddr;
-		void		*voidptr;
-	} modun;
-
-	modun.modaddr = GetProcAddress(hmod, p);
-	return modun.voidptr;
-}
 
-#define lt_dlclose(x)	FreeLibrary(x)
-#define	lt_dlinit()
-#define	lt_dlexit()
-#define lt_dlhandle	HMODULE
+	#define lt_dlclose(x)	FreeLibrary(x)
+	#define	lt_dlinit()
+	#define	lt_dlexit()
+	#define lt_dlhandle	HMODULE
 
-#if	1	/* RXWRXW - dlerror */
-static char	errbuf[64];
-static char *
-lt_dlerror (void)
-{
-	sprintf (errbuf, _("LoadLibrary/GetProcAddress error %d"), (int)GetLastError());
-	return errbuf;
-}
+	#if	1	/* RXWRXW - dlerror */
+	static char	errbuf[64];
+	static char *
+	lt_dlerror (void)
+	{
+		sprintf (errbuf, _("LoadLibrary/GetProcAddress error %d"), (int)GetLastError());
+		return errbuf;
+	}
 #endif
-
 #elif	defined(USE_LIBDL)
-/* note: only defined in configure when HAVE_DLFCN_H is true and dlopen can be linked */
-#include <dlfcn.h>
-
-#define lt_dlopen(x)	dlopen(x, RTLD_LAZY | RTLD_GLOBAL)
-#define lt_dlsym(x,y)	dlsym(x, y)
-#define lt_dlclose(x)	dlclose(x)
-#define lt_dlerror()	dlerror()
-#define	lt_dlinit()
-#define	lt_dlexit()
-#define lt_dlhandle	void *
-
+	/* note: only defined in configure when HAVE_DLFCN_H is true and dlopen can be linked */
+	#include <dlfcn.h>
+
+	#define lt_dlsym(x,y)	dlsym(x, y)
+	#define lt_dlclose(x)	dlclose(x)
+	#define lt_dlerror()	dlerror()
+	#define	lt_dlinit()
+	#define	lt_dlexit()
+	#define lt_dlhandle	void *
 #else
+	#include <ltdl.h>
+#endif
 
-#include <ltdl.h>
+static void* cob_dlopen(const char* filename) {
+#ifdef _WIN32
+	if (filename == NULL) {
+		return GetModuleHandle (NULL);
+	}
+	return LoadLibrary(filename);
+#elif	defined(USE_LIBDL)
+	int flags = cobsetptr->cob_load_global 
+		? RTLD_LAZY | RTLD_GLOBAL
+		: RTLD_LAZY | RTLD_LOCAL;
 
+	return dlopen(filename, flags);
+#else
+	lt_dladvise advise;
+    lt_dladvise_init(&advise);
+
+    if (cobsetptr->cob_load_global) {
+        lt_dladvise_global(&advise);
+    } else {
+        lt_dladvise_local(&advise);
+    }
+
+    void* handle = lt_dlopenadvise(filename, advise);
+    lt_dladvise_destroy(&advise); // Clean up advise object
+    return handle;
 #endif
+}
+
+#define lt_dlopen(x) cob_dlopen(x) // TODO: Remove this!
 
 #define	COB_MAX_COBCALL_PARMS	16
 #define	CALL_BUFF_SIZE		256U
@@ -158,7 +175,6 @@ static struct struct_handle	*base_preload_ptr;
 static struct struct_handle	*base_dynload_ptr;
 
 static cob_global		*cobglobptr = NULL;
-static cob_settings		*cobsetptr = NULL;
 
 static char			**resolve_path;
 static char			*resolve_error;

libcob/coblocal.h

@@ -300,6 +300,7 @@ typedef struct __cob_settings {
 
 	/* call.c */
 	int	cob_physical_cancel;	/* 0 "= "logical only" (default), 1 "also unload", -1 "never unload" */
+	unsigned int	cob_load_global; /* Wether dlopen should use the global or local namespace */
 	unsigned int	name_convert;
 	char		*cob_preload_str;
 	char		*cob_library_path;

libcob/common.c

@@ -490,6 +490,9 @@ static struct config_tbl gc_conf[] = {
 	{"LOGICAL_CANCELS", "logical_cancels", 	NULL, NULL, GRP_HIDE, ENV_BOOL | ENV_NOT, SETPOS (cob_physical_cancel)},
 	{"COB_LIBRARY_PATH", "library_path", 	NULL, 	NULL, GRP_CALL, ENV_PATH, SETPOS (cob_library_path)}, /* default value set in cob_init_call() */
 	{"COB_PRE_LOAD", "pre_load", 		NULL, 	NULL, GRP_CALL, ENV_STR, SETPOS (cob_preload_str)},
+#ifndef _WIN32
+	{"COB_LOAD_GLOBAL", "load_global", "0", NULL, GRP_CALL, ENV_BOOL, SETPOS(cob_load_global)},
+#endif
 	{"COB_BELL", "bell", 			"0", 	beepopts, GRP_SCREEN, ENV_UINT | ENV_ENUMVAL, SETPOS (cob_beep_value)},
 	{"COB_DEBUG_LOG", "debug_log", 		NULL, 	NULL, GRP_HIDE, ENV_FILE, SETPOS (cob_debug_log)},
 	{"COB_DISABLE_WARNINGS", "disable_warnings", "0", 	NULL, GRP_MISC, ENV_BOOL | ENV_NOT, SETPOS (cob_display_warn)},