Move the trampolines for dlopen and related functions from crt0.o

into libc.  This reduces the size of every dynamically linked
executable by 248 bytes, and it reduces the size of static executables
by a lesser amount.  It also eliminates some global namespace
pollution.

With this change in place, the source for dlfcn.h should probably
be moved to "/usr/src/include".  I'll save that for another day.

Compatibility note:  Programs which use dlopen, if compiled on
systems with this change, will not run on systems with a libc from
prior to this change.  Very few programs use dlopen, so I think
that is OK.

lib/csu/i386/Makefile

@@ -1,13 +1,9 @@
 #	from: @(#)Makefile	5.6 (Berkeley) 5/22/91
-#	$Id: Makefile,v 1.33 1998/01/12 18:29:02 eivind Exp $
+#	$Id: Makefile,v 1.34 1998/02/06 16:46:31 jdp Exp $
 
 CFLAGS+=        -DLIBC_SCCS -fno-omit-frame-pointer -I${.CURDIR}
 OBJS=		crt0.o c++rt0.o gcrt0.o scrt0.o sgcrt0.o
 CLEANFILES+=	a.out
-MAN3+=		dladdr.3 dlopen.3
-MLINKS+=	dlopen.3 dlsym.3 \
-		dlopen.3 dlerror.3 \
-		dlopen.3 dlclose.3
 
 all: ${OBJS}
 

lib/csu/i386/crt0.c

@@ -27,7 +27,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- *	$Id: crt0.c,v 1.31 1997/11/22 03:34:45 brian Exp $
+ *	$Id: crt0.c,v 1.32 1998/02/06 16:46:33 jdp Exp $
  */
 
 #include <sys/param.h>
@@ -84,7 +84,6 @@ static int		_strncmp();
 #endif /* LDSO */
 
 extern struct _dynamic	_DYNAMIC;
-static struct ld_entry	*ld_entry;
 static void		__do_dynamic_link(char **argv);
 #endif /* DYNAMIC */
 
@@ -94,7 +93,9 @@ static char		empty[1];
 char			*__progname = empty;
 char			**environ;
 
-static int		ldso_version;
+/* Globals used by dlopen() and related functions in libc */
+struct ld_entry		*__ldso_entry;
+int			__ldso_version;
 
 extern	unsigned char	etext;
 extern	unsigned char	eprol asm ("eprol");
@@ -257,22 +258,22 @@ __do_dynamic_link(argv)
 	crt.crt_argv = argv;
 
 	entry = (int (*)())(crt.crt_ba + sizeof hdr);
-	ldso_version = (*entry)(CRT_VERSION_BSD_5, &crt);
-	ld_entry = crt.crt_ldentry;
-	if (ldso_version == -1 && ld_entry == NULL) {
+	__ldso_version = (*entry)(CRT_VERSION_BSD_5, &crt);
+	__ldso_entry = crt.crt_ldentry;
+	if (__ldso_version == -1 && __ldso_entry == NULL) {
 		/* If version 5 not recognised, try version 4 */
-		ldso_version = (*entry)(CRT_VERSION_BSD_4, &crt);
-		ld_entry = crt.crt_ldentry;
-		if (ldso_version == -1 && ld_entry == NULL) {
+		__ldso_version = (*entry)(CRT_VERSION_BSD_4, &crt);
+		__ldso_entry = crt.crt_ldentry;
+		if (__ldso_version == -1 && __ldso_entry == NULL) {
 			/* if version 4 not recognised, try version 3 */
-			ldso_version = (*entry)(CRT_VERSION_BSD_3, &crt);
-			ld_entry = _DYNAMIC.d_entry;
+			__ldso_version = (*entry)(CRT_VERSION_BSD_3, &crt);
+			__ldso_entry = _DYNAMIC.d_entry;
 		}
 	}
-	if (ldso_version == -1) {
+	if (__ldso_version == -1) {
 		_PUTMSG("ld.so failed");
-		if (ld_entry != NULL) {
-			const char *msg = (ld_entry->dlerror)();
+		if (__ldso_entry != NULL) {
+			const char *msg = (__ldso_entry->dlerror)();
 			if(msg != NULL) {
 				const char *endp;
 				_PUTMSG(": ");
@@ -285,73 +286,12 @@ __do_dynamic_link(argv)
 	}
 
 
-	if (ldso_version >= LDSO_VERSION_HAS_DLEXIT)
-		atexit(ld_entry->dlexit);
+	if (__ldso_version >= LDSO_VERSION_HAS_DLEXIT)
+		atexit(__ldso_entry->dlexit);
 
 	return;
 }
 
-/*
- * DL stubs
- */
-
-void *
-dlopen(name, mode)
-const char *name;
-int	mode;
-{
-	if (ld_entry == NULL)
-		return NULL;
-
-	return (ld_entry->dlopen)(name, mode);
-}
-
-int
-dlclose(fd)
-void	*fd;
-{
-	if (ld_entry == NULL)
-		return -1;
-
-	return (ld_entry->dlclose)(fd);
-}
-
-void *
-dlsym(fd, name)
-void	*fd;
-const char *name;
-{
-	if (ld_entry == NULL)
-		return NULL;
-
-	if (ldso_version >= LDSO_VERSION_HAS_DLSYM3) {
-		void *retaddr = *(&fd - 1);  /* XXX - ABI/machine dependent */
-		return (ld_entry->dlsym3)(fd, name, retaddr);
-	} else
-		return (ld_entry->dlsym)(fd, name);
-}
-
-
-const char *
-dlerror()
-{
-	if (ld_entry == NULL)
-		return "Service unavailable";
-
-	return (ld_entry->dlerror)();
-}
-
-int
-dladdr(addr, dlip)
-	const void	*addr;
-	Dl_info		*dlip;
-{
-	if (ld_entry == NULL || ldso_version < LDSO_VERSION_HAS_DLADDR)
-		return 0;
-	return (ld_entry->dladdr)(addr, dlip);
-}
-
-
 /*
  * Support routines
  */
@@ -407,48 +347,6 @@ _getenv(name)
 	asm("		movl	$-1,%eax");
 	asm("		ret");
 
-#else /* DYNAMIC */
-
-/*
- * DL stubs for static linking case (just return error)
- */
-
-void *
-dlopen(name, mode)
-const char *name;
-int	mode;
-{
-	return NULL;
-}
-
-int
-dlclose(fd)
-void	*fd;
-{
-	return -1;
-}
-
-void *
-dlsym(fd, name)
-void	*fd;
-const char *name;
-{
-	return NULL;
-}
-
-const char *
-dlerror()
-{
-	return "Service unavailable";
-}
-
-int
-dladdr(addr, dlip)
-	const void	*addr;
-	Dl_info		*dlip;
-{
-	return 0;
-}
 #endif /* DYNAMIC */
 
 

lib/libc/gen/Makefile.inc

@@ -1,5 +1,5 @@
 #	@(#)Makefile.inc	8.6 (Berkeley) 5/4/95
-#	$Id: Makefile.inc,v 1.40 1997/10/15 16:15:24 bde Exp $
+#	$Id: Makefile.inc,v 1.41 1997/10/21 08:41:06 bde Exp $
 
 # machine-independent gen sources
 .PATH: ${.CURDIR}/../libc/${MACHINE}/gen ${.CURDIR}/../libc/gen
@@ -7,7 +7,7 @@
 SRCS+=  _rand48.c alarm.c arc4random.c assert.c \
 	clock.c closedir.c config.c confstr.c \
 	crypt.c ctermid.c daemon.c devname.c disklabel.c \
-	drand48.c erand48.c err.c errlst.c \
+	dlfcn.c drand48.c erand48.c err.c errlst.c \
 	exec.c fnmatch.c fstab.c fts.c getbootfile.c getbsize.c \
 	getcap.c getcwd.c getdomainname.c getgrent.c getgrouplist.c \
 	gethostname.c getloadavg.c getlogin.c getmntinfo.c getnetgrent.c \
@@ -45,7 +45,8 @@ errlst.o errlst.po:
 .if ${LIB} == "c"
 MAN3+=  alarm.3 arc4random.3 clock.3 config_open.3 \
 	confstr.3 crypt.3 ctermid.3 daemon.3 \
-	devname.3 directory.3 err.3 exec.3 fnmatch.3 frexp.3 fts.3 \
+	devname.3 directory.3 dladdr.3 dlopen.3 \
+	err.3 exec.3 fnmatch.3 frexp.3 fts.3 \
 	getbootfile.3 getbsize.3 getcap.3 getcwd.3 \
 	getdiskbyname.3 getdomainname.3 getfsent.3 \
 	getgrent.3 getgrouplist.3 gethostname.3 getloadavg.3 \
@@ -69,6 +70,9 @@ MLINKS+=crypt.3 des_cipher.3 crypt.3 des_setkey.3 crypt.3 encrypt.3 \
 MLINKS+=directory.3 closedir.3 directory.3 dirfd.3 directory.3 opendir.3 \
 	directory.3 readdir.3 directory.3 rewinddir.3 directory.3 seekdir.3 \
 	directory.3 telldir.3
+MLINKS+=dlopen.3 dlsym.3 \
+	dlopen.3 dlerror.3 \
+	dlopen.3 dlclose.3
 MLINKS+=exec.3 execl.3 exec.3 execle.3 exec.3 execlp.3 exec.3 exect.3 \
 	exec.3 execv.3 exec.3 execvp.3
 MLINKS+=err.3 err_set_exit.3 err.3 err_set_file.3 err.3 errx.3 err.3 verr.3 \

lib/libc/gen/dladdr.3

@@ -23,7 +23,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"	$Id$
+.\"	$Id: dladdr.3,v 1.1 1998/02/06 16:46:34 jdp Exp $
 .\"
 .Dd February 5, 1998
 .Os FreeBSD

lib/libc/gen/dlfcn.c

@@ -0,0 +1,96 @@
+/*-
+ * Copyright (c) 1998 John D. Polstra
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	$Id$
+ */
+
+/*
+ * Trampolines to services provided by the dynamic linker.
+ */
+
+#include <sys/types.h>
+#include <nlist.h>		/* XXX - Required by link.h */
+#include <dlfcn.h>
+#include <link.h>
+#include <stddef.h>
+
+/*
+ * These variables are set by code in crt0.o.  For compatibility with
+ * old executables, they must be common, not extern.
+ */
+struct ld_entry	*__ldso_entry;		/* Entry points to dynamic linker */
+int		 __ldso_version;	/* Dynamic linker version number */
+
+void *
+dlopen(name, mode)
+	const char	*name;
+	int		 mode;
+{
+	if (__ldso_entry == NULL)
+		return NULL;
+	return (__ldso_entry->dlopen)(name, mode);
+}
+
+int
+dlclose(fd)
+	void		*fd;
+{
+	if (__ldso_entry == NULL)
+		return -1;
+	return (__ldso_entry->dlclose)(fd);
+}
+
+void *
+dlsym(fd, name)
+	void		*fd;
+	const char	*name;
+{
+	if (__ldso_entry == NULL)
+		return NULL;
+	if (__ldso_version >= LDSO_VERSION_HAS_DLSYM3) {
+		void *retaddr = *(&fd - 1);  /* XXX - ABI/machine dependent */
+		return (__ldso_entry->dlsym3)(fd, name, retaddr);
+	} else
+		return (__ldso_entry->dlsym)(fd, name);
+}
+
+
+const char *
+dlerror()
+{
+	if (__ldso_entry == NULL)
+		return "Service unavailable";
+	return (__ldso_entry->dlerror)();
+}
+
+int
+dladdr(addr, dlip)
+	const void	*addr;
+	Dl_info		*dlip;
+{
+	if (__ldso_entry == NULL || __ldso_version < LDSO_VERSION_HAS_DLADDR)
+		return 0;
+	return (__ldso_entry->dladdr)(addr, dlip);
+}