[dm-devel] [PATCH v2 09/12] libmultipath: add linker version script

[mwilck at suse.com]

From: Martin Wilck <mwilck at suse.com>

This version script documents the current ABI of libmultipath,
as used by multipath, multipathd, (lib)mpathpersist, and the
dynamically loaded libraries (prioritizers, checkers, and foreign).
The initial version string is set to "LIBMULTIPATH_1.0.0".

This reduces the amount of exported symbols of libmultipath.so.0
by more than a half (199 vs. 434).

Reviewed-by: Benjamin Marzinski <bmarzins at redhat.com>
Signed-off-by: Martin Wilck <mwilck at suse.com>
---
 libmultipath/Makefile             |   7 +-
 libmultipath/libmultipath.version | 248 ++++++++++++++++++++++++++++++
 2 files changed, 253 insertions(+), 2 deletions(-)
 create mode 100644 libmultipath/libmultipath.version

diff --git a/libmultipath/Makefile b/libmultipath/Makefile
index cf13561..bfc7263 100644
--- a/libmultipath/Makefile
+++ b/libmultipath/Makefile
@@ -6,6 +6,7 @@ include ../Makefile.inc
 SONAME = 0
 DEVLIB = libmultipath.so
 LIBS = $(DEVLIB).$(SONAME)
+VERSION_SCRIPT := libmultipath.version
 
 CFLAGS += $(LIB_CFLAGS) -I$(mpathcmddir) -I$(mpathpersistdir) -I$(nvmedir)
 
@@ -68,8 +69,10 @@ nvme-ioctl.c: nvme/nvme-ioctl.c
 nvme-ioctl.h: nvme/nvme-ioctl.h
 	$(call make_static,$<,$@)
 
-$(LIBS): $(OBJS)
-	$(CC) $(LDFLAGS) $(SHARED_FLAGS) -Wl,-soname=$@ -o $@ $(OBJS) $(LIBDEPS)
+
+$(LIBS): $(OBJS) $(VERSION_SCRIPT)
+	$(CC) $(LDFLAGS) $(SHARED_FLAGS) -Wl,-soname=$@ \
+		-Wl,--version-script=$(VERSION_SCRIPT) -o $@ $(OBJS) $(LIBDEPS)
 
 $(DEVLIB): $(LIBS)
 	$(LN) $(LIBS) $@
diff --git a/libmultipath/libmultipath.version b/libmultipath/libmultipath.version
new file mode 100644
index 0000000..a6bf821
--- /dev/null
+++ b/libmultipath/libmultipath.version
@@ -0,0 +1,248 @@
+/*
+ * Copyright (c) 2020 SUSE LLC
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * libmultipath ABI
+ *
+ * libmultipath doesn't have a stable ABI in the usual sense. In particular,
+ * the library does not attempt to ship different versions of the same symbol
+ * for backward compatibility.
+ *
+ * The ABI versioning only serves to avoid linking with a non-matching ABI, to
+ * cut down the set of exported symbols, and to describe it.
+ * The version string is LIBMULTIPATH_$MAJOR.$MINOR.$REL.
+ *
+ * Policy:
+ *
+ * * Bump $MAJOR for incompatible changes, like:
+ *   - symbols removed
+ *   - parameter list or return values changed for existing functions
+ *   - externally visible data structures changed in incompatible ways
+ *     (like offsets of previously existing struct members)
+ *   In this case, the new version doesn't inherit the previous versions,
+ *   because the new library doesn't provide the full previous ABI any more.
+ *   All predecessors are merged into the new version.
+ *
+ * * Bump $MINOR for compatible changes, like adding symbols.
+ *   The new version inherits the previous ones.
+ *
+ * * Bump $REL to describe deviations from upstream, e.g. in
+ *   multipath-tools packages shipped by distributions.
+ *   The new version inherits the previous ones.
+ */
+
+LIBMULTIPATH_1.0.0 {
+global:
+	/* symbols referenced by multipath and multipathd */
+	add_foreign;
+	add_map_with_path;
+	adopt_paths;
+	alloc_multipath;
+	alloc_path;
+	alloc_path_with_pathinfo;
+	alloc_strvec;
+	change_foreign;
+	check_alias_settings;
+	checker_clear_message;
+	checker_disable;
+	checker_enable;
+	checker_is_sync;
+	checker_message;
+	checker_name;
+	checker_state_name;
+	check_foreign;
+	cleanup_checkers;
+	cleanup_foreign;
+	cleanup_lock;
+	cleanup_prio;
+	close_fd;
+	coalesce_paths;
+	convert_dev;
+	count_active_paths;
+	delete_all_foreign;
+	delete_foreign;
+	disassemble_map;
+	disassemble_status;
+	dlog;
+	dm_cancel_deferred_remove;
+	dm_drv_version;
+	dm_enablegroup;
+	dm_fail_path;
+	_dm_flush_map;
+	dm_flush_map_nopaths;
+	dm_flush_maps;
+	dm_geteventnr;
+	dm_get_info;
+	dm_get_major_minor;
+	dm_get_map;
+	dm_get_maps;
+	dm_get_multipath;
+	dm_get_status;
+	dm_get_uuid;
+	dm_is_mpath;
+	dm_mapname;
+	dm_map_present;
+	dm_queue_if_no_path;
+	dm_reassign;
+	dm_reinstate_path;
+	dm_simplecmd_noflush;
+	dm_switchgroup;
+	dm_tgt_version;
+	domap;
+	ensure_directories_exist;
+	extract_hwe_from_path;
+	filter_devnode;
+	filter_path;
+	filter_wwid;
+	find_mp_by_alias;
+	find_mp_by_minor;
+	find_mp_by_str;
+	find_mp_by_wwid;
+	find_mpe;
+	find_path_by_dev;
+	find_path_by_devt;
+	find_slot;
+	foreign_multipath_layout;
+	foreign_path_layout;
+	free_config;
+	free_multipath;
+	free_multipathvec;
+	free_path;
+	free_pathvec;
+	free_strvec;
+	get_monotonic_time;
+	get_multipath_layout;
+	get_path_layout;
+	get_pgpolicy_id;
+	get_refwwid;
+	get_state;
+	get_udev_device;
+	get_uid;
+	get_used_hwes;
+	group_by_prio;
+	init_checkers;
+	init_foreign;
+	init_prio;
+	io_err_stat_attr;
+	io_err_stat_handle_pathfail;
+	is_path_valid;
+	is_quote;
+	libmp_dm_task_create;
+	libmp_udev_set_sync_support;
+	load_config;
+	log_thread_reset;
+	log_thread_start;
+	log_thread_stop;
+	need_io_err_check;
+	normalize_timespec;
+	orphan_path;
+	orphan_paths;
+	parse_prkey_flags;
+	pathcount;
+	path_discovery;
+	path_get_tpgs;
+	pathinfo;
+	path_offline;
+	print_all_paths;
+	print_foreign_topology;
+	_print_multipath_topology;
+	pthread_cond_init_mono;
+	recv_packet;
+	recv_packet_from_client;
+	reinstate_paths;
+	remember_wwid;
+	remove_map;
+	remove_map_by_alias;
+	remove_maps;
+	remove_wwid;
+	replace_wwids;
+	reset_checker_classes;
+	select_all_tg_pt;
+	select_action;
+	select_find_multipaths_timeout;
+	select_no_path_retry;
+	select_path_group;
+	select_reservation_key;
+	send_packet;
+	set_max_fds;
+	__set_no_path_retry;
+	set_path_removed;
+	set_prkey;
+	setup_map;
+	setup_thread_attr;
+	should_multipath;
+	snprint_blacklist_report;
+	snprint_config;
+	snprint_devices;
+	snprint_foreign_multipaths;
+	snprint_foreign_paths;
+	snprint_foreign_topology;
+	_snprint_multipath;
+	snprint_multipath_header;
+	snprint_multipath_map_json;
+	_snprint_multipath_topology;
+	snprint_multipath_topology_json;
+	_snprint_path;
+	snprint_path_header;
+	snprint_status;
+	snprint_wildcards;
+	stop_io_err_stat_thread;
+	store_path;
+	store_pathinfo;
+	strchop;
+	strlcpy;
+	sync_map_state;
+	sysfs_attr_set_value;
+	sysfs_get_size;
+	sysfs_is_multipathed;
+	timespecsub;
+	trigger_paths_udev_change;
+	uevent_dispatch;
+	uevent_get_dm_str;
+	uevent_get_env_positive_int;
+	uevent_is_mpath;
+	uevent_listen;
+	update_mpp_paths;
+	update_multipath_status;
+	update_multipath_strings;
+	update_multipath_table;
+	update_pathvec_from_dm;
+	update_queue_mode_add_path;
+	update_queue_mode_del_path;
+	ux_socket_listen;
+	valid_alias;
+	vector_alloc;
+	vector_alloc_slot;
+	vector_del_slot;
+	vector_free;
+	vector_reset;
+	vector_set_slot;
+	verify_paths;
+
+	/* checkers */
+	sg_read;
+
+	/* prioritizers */
+	get_asymmetric_access_state;
+	get_prio_timeout;
+	get_target_port_group;
+	get_target_port_group_support;
+	libmp_nvme_ana_log;
+	libmp_nvme_get_nsid;
+	libmp_nvme_identify_ns;
+	log_nvme_errcode;
+	nvme_id_ctrl_ana;
+	snprint_host_wwnn;
+	snprint_host_wwpn;
+	snprint_path_serial;
+	snprint_tgt_wwnn;
+	snprint_tgt_wwpn;
+	sysfs_get_asymmetric_access_state;
+
+	/* foreign */
+	free_scandir_result;
+	sysfs_attr_get_value;
+
+local:
+	*;
+};
-- 
2.28.0