add linker version script to hide internal syms

Makefile

@@ -8,6 +8,8 @@ all:
 	gcc -O0 $(WARNFLAGS) -g main.c tcplay.c crc32.c safe_mem.c io.c crypto-dev.c hdr.c -o tc-play -lcrypto -ldevmapper -lprop -lutil
 lib:
 	gcc $(WARNFLAGS) -c -fPIC -O0 -Wall -g tcplay_api.c tcplay.c crc32.c safe_mem.c io.c crypto-dev.c hdr.c
-	gcc -shared -Wl -o libtcplay.so tcplay_api.o tcplay.o crc32.o safe_mem.o io.o crypto-dev.o hdr.o
+	gcc -shared -Wl,-version-script=tcplay.map -o libtcplay.so tcplay_api.o tcplay.o crc32.o safe_mem.o io.o crypto-dev.o hdr.o
+test:
+	gcc -O0 -g -L. -I. tcplay_api_test.c -ltcplay -lcrypto -ldevmapper -lprop -lutil
 clean:
 	rm -f tc-play tc-play.core *.o ktrace.out

tcplay.map

@@ -0,0 +1,13 @@
+{
+global:
+	tc_api_init;
+	tc_api_uninit;
+	tc_api_create_volume;
+	tc_api_map_volume;
+	tc_api_check_cipher;
+	tc_api_check_prf_hash;
+	tc_api_get_error_msg;
+	tc_api_get_summary;
+local:
+	*;
+};