multipathd: replace libreadline with libedit

Linking multipathd with libreadline may cause a license conflict,
because libreadline is licensed under GPL-3.0-or-later, and
libmultipath contains several files under GPL-2.0.

See:
   opensvc/multipath-tools#36
   https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=979095
   https://www.gnu.org/licenses/gpl-faq.html#AllCompatibility

Replace the readline functionality with libedit, which comes under
a BSD license. The readline library can still be enabled (e.g. for
binaries not intended to be distributed) by running
"make READLINE=libreadline".

Signed-off-by: Martin Wilck <[email protected]>

Makefile.inc

@@ -14,6 +14,11 @@
 #
 # Uncomment to disable dmevents polling support
 # ENABLE_DMEVENTS_POLL = 0
+#
+# Readline library to use, libedit or libreadline
+# Caution: Using libreadline may make the multipathd binary undistributable,
+# see https://github.com/opensvc/multipath-tools/issues/36
+READLINE = libedit
 
 ifeq ($(TOPDIR),)
 	TOPDIR	= ..

multipathd/Makefile

@@ -15,7 +15,16 @@ CFLAGS += $(BIN_CFLAGS) -I$(multipathdir) -I$(mpathpersistdir) \
 LDFLAGS += $(BIN_LDFLAGS)
 LIBDEPS += -L$(multipathdir) -lmultipath -L$(mpathpersistdir) -lmpathpersist \
 	   -L$(mpathcmddir) -lmpathcmd -ludev -ldl -lurcu -lpthread \
-	   -ldevmapper -lreadline
+	   -ldevmapper
+
+ifeq ($(READLINE),libedit)
+CPPFLAGS += -DUSE_LIBEDIT
+LIBDEPS += -ledit
+endif
+ifeq ($(READLINE),libreadline)
+CPPFLAGS += -DUSE_LIBREADLINE
+LIBDEPS += -lreadline
+endif
 
 ifdef SYSTEMD
 	CFLAGS += -DUSE_SYSTEMD=$(SYSTEMD)

multipathd/cli.c

@@ -11,7 +11,12 @@
 #include "parser.h"
 #include "util.h"
 #include "version.h"
+#ifdef USE_LIBEDIT
+#include <editline/readline.h>
+#endif
+#ifdef USE_LIBREADLINE
 #include <readline/readline.h>
+#endif
 
 #include "mpath_cmd.h"
 #include "cli.h"

multipathd/uxclnt.c

@@ -15,8 +15,14 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <poll.h>
+
+#ifdef USE_LIBEDIT
+#include <editline/readline.h>
+#endif
+#ifdef USE_LIBREADLINE
 #include <readline/readline.h>
 #include <readline/history.h>
+#endif
 
 #include "mpath_cmd.h"
 #include "uxsock.h"