MFC r320872:

Create libdl.so.1 as a filter for libc.so.7 which exports public dl*
functions.

9 files changed, 65 insertions, 1 deletions

diff --git a/contrib/mdocml/lib.in b/contrib/mdocml/lib.in
index e74b8ac..76691ec 100644
--- a/contrib/mdocml/lib.in
+++ b/contrib/mdocml/lib.in
@@ -46,6 +46,7 @@ LINE("libdevctl",	"Device Control Library (libdevctl, \\-ldevctl)")
 LINE("libdevinfo",	"Device and Resource Information Utility Library (libdevinfo, \\-ldevinfo)")
 LINE("libdevstat",	"Device Statistics Library (libdevstat, \\-ldevstat)")
 LINE("libdisk",		"Interface to Slice and Partition Labels Library (libdisk, \\-ldisk)")
+LINE("libdl",		"Dynamic Linker Services Filter (libdl, \\-ldl)")
 LINE("libdm",		"Device Mapper Library (libdm, \\-ldm)")
 LINE("libdwarf",	"DWARF Access Library (libdwarf, \\-ldwarf)")
 LINE("libedit",		"Command Line Editor Library (libedit, \\-ledit)")
diff --git a/lib/Makefile b/lib/Makefile
index ae8ab9b..242c463 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -47,6 +47,7 @@ SUBDIR=	${SUBDIR_BOOTSTRAP} \
 	libdevdctl \
 	libdevinfo \
 	libdevstat \
+	${_libdl} \
 	libdwarf \
 	libedit \
 	${_libefivar} \
@@ -275,6 +276,10 @@ _libproc=	libproc
 _librtld_db=	librtld_db
 .endif
 
+.if defined(LINKER_FEATURES) && ${LINKER_FEATURES:Mfilter}
+_libdl=		libdl
+.endif
+
 .if ${MACHINE_CPUARCH} == "aarch64" || ${MACHINE_CPUARCH} == "arm" || \
     ${MACHINE_CPUARCH} == "riscv"
 _libproc=	libproc
diff --git a/lib/libc/gen/dlfcn.c b/lib/libc/gen/dlfcn.c
index 393b02a..55e7fc7 100644
--- a/lib/libc/gen/dlfcn.c
+++ b/lib/libc/gen/dlfcn.c
@@ -27,6 +27,8 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#if !defined(IN_LIBDL) || defined(PIC)
+
 /*
  * Linkage to services provided by the dynamic linker.
  */
@@ -157,6 +159,7 @@ _rtld_thread_init(void *li __unused)
 	_rtld_error(sorry);
 }
 
+#ifndef IN_LIBDL
 static pthread_once_t dl_phdr_info_once = PTHREAD_ONCE_INIT;
 static struct dl_phdr_info phdr_info;
 
@@ -192,6 +195,7 @@ dl_init_phdr_info(void)
 	}
 	phdr_info.dlpi_adds = 1;
 }
+#endif
 
 #pragma weak dl_iterate_phdr
 int
@@ -199,11 +203,15 @@ dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *) __unused,
     void *data __unused)
 {
 
+#ifndef IN_LIBDL
 	__init_elf_aux_vector();
 	if (__elf_aux_vector == NULL)
 		return (1);
 	_once(&dl_phdr_info_once, dl_init_phdr_info);
 	return (callback(&phdr_info, sizeof(phdr_info), data));
+#else
+	return (0);
+#endif
 }
 
 #pragma weak fdlopen
@@ -251,3 +259,5 @@ _rtld_is_dlopened(void *arg __unused)
 
 	return (0);
 }
+
+#endif /* !defined(IN_LIBDL) || defined(PIC) */
diff --git a/lib/libc/gen/dlopen.3 b/lib/libc/gen/dlopen.3
index 1963528..202f1af 100644
--- a/lib/libc/gen/dlopen.3
+++ b/lib/libc/gen/dlopen.3
@@ -32,7 +32,7 @@
 .\" @(#) dlopen.3 1.6 90/01/31 SMI
 .\" $FreeBSD$
 .\"
-.Dd February 14, 2015
+.Dd July 7, 2017
 .Dt DLOPEN 3
 .Os
 .Sh NAME
@@ -377,6 +377,14 @@ option to
 for symbols defined in the executable to become visible to
 .Fn dlsym .
 .Pp
+Other ELF platforms require linking with
+.Lb libdl
+to provide
+.Fn dlopen
+and other functions.
+.Fx
+does not require linking with the library, but supports it for compatibility.
+.Pp
 In previous implementations, it was necessary to prepend an underscore
 to all external symbols in order to gain symbol
 compatibility with object code compiled from the C language.
diff --git a/lib/libdl/Makefile b/lib/libdl/Makefile
new file mode 100644
index 0000000..8feb782
--- /dev/null
+++ b/lib/libdl/Makefile
@@ -0,0 +1,15 @@
+# $FreeBSD$
+
+LIB=dl
+SHLIB_MAJOR=1
+
+.PATH:	${SRCTOP}/lib/libc/gen
+CFLAGS+=-I${SRCTOP}/lib/libc/include
+CFLAGS+=-DIN_LIBDL
+LDFLAGS+=-Wl,-F,libc.so.7
+VERSION_DEF=${SRCTOP}/lib/libc/Versions.def
+SYMBOL_MAPS=${.CURDIR}/Symbol.map
+
+SRCS =	dlfcn.c
+
+.include <bsd.lib.mk>
diff --git a/lib/libdl/Symbol.map b/lib/libdl/Symbol.map
new file mode 100644
index 0000000..82ab601
--- /dev/null
+++ b/lib/libdl/Symbol.map
@@ -0,0 +1,20 @@
+/*
+ * $FreeBSD$
+ */
+
+FBSD_1.0 {
+	dladdr;
+	dlclose;
+	dlerror;
+	dlfunc;
+	dlopen;
+	dlsym;
+	dlvsym;
+	dlinfo;
+	dl_iterate_phdr;
+};
+
+
+FBSD_1.3 {
+	fdlopen;
+};
diff --git a/share/mk/bsd.libnames.mk b/share/mk/bsd.libnames.mk
index 28be843..07e7a4c 100644
--- a/share/mk/bsd.libnames.mk
+++ b/share/mk/bsd.libnames.mk
@@ -54,6 +54,7 @@ LIBDEVDCTL?=	${DESTDIR}${LIBDIR_BASE}/libdevdctl.a
 LIBDEVINFO?=	${DESTDIR}${LIBDIR_BASE}/libdevinfo.a
 LIBDEVSTAT?=	${DESTDIR}${LIBDIR_BASE}/libdevstat.a
 LIBDIALOG?=	${DESTDIR}${LIBDIR_BASE}/libdialog.a
+LIBDL?=		${DESTDIR}${LIBDIR_BASE}/libdl.a
 LIBDNS?=	${DESTDIR}${LIBDIR_BASE}/libdns.a
 LIBDPV?=	${DESTDIR}${LIBDIR_BASE}/libdpv.a
 LIBDTRACE?=	${DESTDIR}${LIBDIR_BASE}/libdtrace.a
diff --git a/share/mk/bsd.linker.mk b/share/mk/bsd.linker.mk
index 90691f7..791ee16 100644
--- a/share/mk/bsd.linker.mk
+++ b/share/mk/bsd.linker.mk
@@ -70,6 +70,9 @@ ${X_}LINKER_FEATURES=
 .if ${${X_}LINKER_TYPE} != "bfd" || ${${X_}LINKER_VERSION} > 21750
 ${X_}LINKER_FEATURES+=	build-id
 .endif
+.if ${${X_}LINKER_TYPE} == "bfd"
+${X_}LINKER_FEATURES+=	filter
+.endif
 .endif
 .else
 # Use LD's values
diff --git a/share/mk/src.libnames.mk b/share/mk/src.libnames.mk
index bfe8c4f..ac3f9c2 100644
--- a/share/mk/src.libnames.mk
+++ b/share/mk/src.libnames.mk
@@ -87,6 +87,7 @@ _LIBRARIES=	\
 		devinfo \
 		devstat \
 		dialog \
+		dl \
 		dpv \
 		dtrace \
 		dwarf \