[PATCH] libsemanage: check libsepol version

[bill.c.roberts@gmail.com]

From: William Roberts <william.c.roberts@intel.com>

If libsepol is older than version 3.0, the required routine
sepol_policydb_optimize will not be present. Use pkg-config to get the
modversion and check that it is 3.0 or higher.

This can manifest as a compilation issue:
direct_api.c: In function ‘semanage_direct_commit’:
direct_api.c:1466:13: error: implicit declaration of function ‘sepol_policydb_optimize’; did you mean ‘sepol_policydb_to_image’? [-Werror=implicit-function-declaration]
     retval = sepol_policydb_optimize(out);

Which is not really clear on how to check.

Signed-off-by: William Roberts <william.c.roberts@intel.com>
---
 libsemanage/src/Makefile | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/libsemanage/src/Makefile b/libsemanage/src/Makefile
index f6780dc6048e..a329797fe1cc 100644
--- a/libsemanage/src/Makefile
+++ b/libsemanage/src/Makefile
@@ -65,6 +65,14 @@ SWIG = swig -Wall -python -o $(SWIGCOUT) -outdir ./
 
 SWIGRUBY = swig -Wall -ruby -o $(SWIGRUBYCOUT) -outdir ./
 
+sepol-version-check:
+	@v=$$($(PKG_CONFIG) --modversion libsepol); \
+	major=$$(echo "$$v" | cut -d"." -f 1-1); \
+	if [ "$$major" -lt 3 ]; then \
+		>&2 echo "libsepol is required to be version 3.0 or higher, got: $$v"; \
+		exit 1; \
+	fi
+
 all: $(LIBA) $(LIBSO) $(LIBPC)
 
 pywrap: all $(SWIGSO)
@@ -83,12 +91,12 @@ $(SWIGSO): $(SWIGLOBJ)
 $(SWIGRUBYSO): $(SWIGRUBYLOBJ)
 	$(CC) $(CFLAGS) $(LDFLAGS) -L. -shared -o $@ $^ -lsemanage $(RUBYLIBS)
 
-$(LIBA): $(OBJS)
-	$(AR) rcs $@ $^
+$(LIBA): sepol-version-check $(OBJS)
+	$(AR) rcs $@ $(filter-out $<,$^)
 	$(RANLIB) $@
 
-$(LIBSO): $(LOBJS)
-	$(CC) $(CFLAGS) $(LDFLAGS) -shared -o $@ $^ -lsepol -laudit -lselinux -lbz2 -Wl,-soname,$(LIBSO),--version-script=libsemanage.map,-z,defs
+$(LIBSO): sepol-version-check $(LOBJS)
+	$(CC) $(CFLAGS) $(LDFLAGS) -shared -o $@ $(filter-out $<,$^) -lsepol -laudit -lselinux -lbz2 -Wl,-soname,$(LIBSO),--version-script=libsemanage.map,-z,defs
 	ln -sf $@ $(TARGET)
 
 $(LIBPC): $(LIBPC).in ../VERSION
@@ -163,4 +171,4 @@ distclean: clean
 indent:
 	../../scripts/Lindent $(filter-out $(GENERATED),$(wildcard *.[ch]))
 
-.PHONY: all clean pywrap rubywrap swigify install install-pywrap install-rubywrap distclean
+.PHONY: all clean pywrap rubywrap swigify install install-pywrap install-rubywrap distclean sepol-version-check
-- 
2.17.1