Library ABI tracking with abigail

Provide two make targets: checkabi and storeabi.

storeabi uses libabigail to generate a reference copy of the ABI for the
public libraries.

checkabi compares such a reference to the compiled version, failing if
they are not compatible.  No ABI is generated for libzpool.so, it is
only used by ztest and zdb and not external consumers.

Co-authored-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Antonio Russo <aerusso@aerusso.net>
Closes #11144

Makefile.am

@@ -136,6 +136,13 @@ shellcheck:
 		echo "skipping shellcheck because shellcheck is not installed"; \
 	fi
 
+PHONY += checkabi storeabi
+checkabi: lib
+	$(MAKE) -C lib checkabi
+
+storeabi: lib
+	$(MAKE) -C lib storeabi
+
 PHONY += checkbashisms
 checkbashisms:
 	@if type checkbashisms > /dev/null 2>&1; then \

config/Abigail.am

@@ -0,0 +1,29 @@
+#
+# When performing an ABI check the following options are applied:
+#
+# --no-unreferenced-symbols: Exclude symbols which are not referenced by
+# any debug information.  Without this _init() and _fini() are incorrectly
+# reported on CentOS7 for libuutil.so.
+#
+# --headers-dir1: Limit ABI checks to public OpenZFS headers, otherwise
+# changes in public system headers are also reported.
+#
+# --suppressions: Honor a suppressions file for each library to provide
+# a mechanism for suppressing harmless warnings.
+#
+
+PHONY += checkabi storeabi
+
+checkabi:
+	for lib in $(lib_LTLIBRARIES) ; do \
+		abidiff --no-unreferenced-symbols \
+		    --headers-dir1 ../../include \
+		    --suppressions $${lib%.la}.suppr \
+		    $${lib%.la}.abi .libs/$${lib%.la}.so ; \
+	done
+
+storeabi:
+	cd .libs ; \
+	for lib in $(lib_LTLIBRARIES) ; do \
+		abidw $${lib%.la}.so > ../$${lib%.la}.abi ; \
+	done

lib/Makefile.am

@@ -15,4 +15,21 @@ SUBDIRS += libzutil libunicode
 
 # These five libraries, which are installed as the final build product,
 # incorporate the eight convenience libraries given above.
-SUBDIRS += libuutil libzfs_core libzfs libzpool libzfsbootenv
+DISTLIBS = libuutil libzfs_core libzfs libzpool libzfsbootenv
+SUBDIRS += $(DISTLIBS)
+DISTLIBS += libnvpair
+
+# An ABI is stored for each of these libraries.  Note that libzpool.so
+# is only linked against by ztest and zdb and no stable ABI is provided.
+ABILIBS = libnvpair libuutil libzfs_core libzfs libzfsbootenv
+
+PHONY = checkabi storeabi
+checkabi: $(ABILIBS)
+	set -e ; for dir in $(ABILIBS) ; do \
+		$(MAKE) -C $$dir checkabi ; \
+	done
+
+storeabi: $(ABILIBS)
+	set -e ; for dir in $(ABILIBS) ; do \
+		$(MAKE) -C $$dir storeabi ; \
+	done

lib/libnvpair/Makefile.am

@@ -1,4 +1,5 @@
 include $(top_srcdir)/config/Rules.am
+PHONY =
 
 VPATH = \
 	$(top_srcdir)/module/nvpair \
@@ -10,6 +11,8 @@ AM_CFLAGS += $(FRAME_LARGER_THAN) $(LIBTIRPC_CFLAGS)
 
 lib_LTLIBRARIES = libnvpair.la
 
+include $(top_srcdir)/config/Abigail.am
+
 USER_C = \
 	libnvpair.c \
 	libnvpair_json.c \

lib/libnvpair/libnvpair.suppr

@@ -0,0 +1,2 @@
+[suppress_type]
+	name = FILE*

lib/libuutil/Makefile.am

@@ -1,7 +1,10 @@
 include $(top_srcdir)/config/Rules.am
+PHONY =
 
 lib_LTLIBRARIES = libuutil.la
 
+include $(top_srcdir)/config/Abigail.am
+
 USER_C = \
 	uu_alloc.c \
 	uu_avl.c \

lib/libuutil/libuutil.suppr

@@ -0,0 +1,2 @@
+[suppress_type]
+	name = FILE*

lib/libzfs/Makefile.am

@@ -1,4 +1,5 @@
 include $(top_srcdir)/config/Rules.am
+PHONY =
 
 VPATH = \
 	$(top_srcdir)/module/icp \
@@ -13,6 +14,8 @@ pkgconfig_DATA = libzfs.pc
 
 lib_LTLIBRARIES = libzfs.la
 
+include $(top_srcdir)/config/Abigail.am
+
 USER_C = \
 	libzfs_changelist.c \
 	libzfs_config.c \

lib/libzfs/libzfs.suppr

@@ -0,0 +1,13 @@
+[suppress_type]
+	name = FILE*
+
+[suppress_type]
+	type_kind = typedef
+	name = SHA256_CTX
+
+[suppress_type]
+	type_kind = typedef
+	name = SHA2_CTX
+
+[suppress_variable]
+	name = zfs_deleg_perm_tab

lib/libzfs_core/Makefile.am

@@ -1,9 +1,12 @@
 include $(top_srcdir)/config/Rules.am
+PHONY =
 
 pkgconfig_DATA = libzfs_core.pc
 
 lib_LTLIBRARIES = libzfs_core.la
 
+include $(top_srcdir)/config/Abigail.am
+
 USER_C = \
 	libzfs_core.c
 

lib/libzfs_core/libzfs_core.suppr

@@ -0,0 +1,5 @@
+[suppress_type]
+	name = FILE*
+
+[suppress_type]
+	name = pthread_cond_t

lib/libzfsbootenv/Makefile.am

@@ -1,9 +1,12 @@
 include $(top_srcdir)/config/Rules.am
+PHONY =
 
 pkgconfig_DATA = libzfsbootenv.pc
 
 lib_LTLIBRARIES = libzfsbootenv.la
 
+include $(top_srcdir)/config/Abigail.am
+
 if BUILD_FREEBSD
 DEFAULT_INCLUDES += -I$(top_srcdir)/include/os/freebsd/zfs
 endif

lib/libzfsbootenv/libzfsbootenv.suppr

@@ -0,0 +1,2 @@
+[suppress_type]
+	name = FILE*