Added versioning to library

Author: dtcooper

Makefile

@@ -45,6 +45,9 @@ all: $(LIB_FILE) $(CMD_FILE)
 %.$(LIB_SUFFIX): %.c
 	$(CC) $(CFLAGS) $(CLIBFLAGS) $(CDEFS) $< -o $@ $(LDLIBS)
 
+$(CMD_FILE): $(CMD_FILE).c
+	$(CC) $(CFLAGS) $(CDEFS) $< -o $@ $(LDLIBS)
+
 %: %.c
 	$(CC) $(CFLAGS) $(CDEFS) $< -o $@
 

extras/test.sh

@@ -89,7 +89,12 @@ if [ "$IS_LINUX" ]; then
 else
     ACTUAL="$(DYLD_INSERT_LIBRARIES="./time_preload.dylib" DYLD_FORCE_FLAT_NAMESPACE=1 ./fakehostname hi ./example all | strip_newlines)"
 fi
-run_test "Preserve pre-existing preload (time)" "$EXPECTED" "$ACTUAL"
+run_test "preserve pre-existing preload (time)" "$EXPECTED" "$ACTUAL"
+
+GIT_VER="$(git describe --tags --always --dirty 2>/dev/null || echo unknown)"
+EXPECTED="fakehostname version: $GIT_VER|libfakehostname version: $GIT_VER (./libfakehostname.$LIB_SUFFIX)"
+ACTUAL="$(./fakehostname -V | strip_newlines)"
+run_test "version check" "$EXPECTED" "$ACTUAL"
 
 echo
 if [ "$FAILED" -gt 0 ]; then

src/fakehostname.c

@@ -1,3 +1,4 @@
+#include <dlfcn.h>
 #include <errno.h>
 #include <getopt.h>
 #include <libgen.h>
@@ -62,11 +63,30 @@ char *get_lib_path() {
     exit(EXIT_FAILURE);
 }
 
+void print_version() {
+    printf("fakehostname version: " FAKE_HOSTNAME_VERSION "\n");
+
+    char *lib_path = get_lib_path();
+    void *lib_handle = dlopen(lib_path, RTLD_LAZY);
+    if (!lib_handle) {
+        printf("Error opening library %s: \"%s\"\n", lib_path, dlerror());
+        return;
+    }
+
+    char **lib_version = dlsym(lib_handle, "version");
+
+    char *error;
+    if ((error = dlerror()) != NULL)  {
+        printf("Error loading \"version\" from %s: \"%s\"\n", lib_path, error);
+        return;
+    }
+
+    printf("libfakehostname version: %s (%s)\n", *lib_version, lib_path);
+}
 
 void usage(char *cmd_name, int exit_code) {
     printf(
-        "fakehostname version " FAKE_HOSTNAME_VERSION "\n\n"
-        "Usage: %s [-h"
+        "\nUsage: %s [-h"
 #ifdef ENABLE_VERBOSE
         "v"
 #endif
@@ -86,6 +106,10 @@ void usage(char *cmd_name, int exit_code) {
         "  -V, --version       Print version information and exit\n\n"
         "...and remember kids, have fun!\n\n",
     basename(cmd_name));
+#ifdef ENABLE_VERBOSE
+    verbose = 0; //shutup possible verbose output in print_version() here
+#endif
+    print_version();
     exit(exit_code);
 }
 
@@ -122,7 +146,7 @@ int parse_options(int argc, char **argv) {
                 break;
 #endif
             case 'V':
-                printf("fakehostname version " FAKE_HOSTNAME_VERSION "\n");
+                print_version();
                 exit(EXIT_SUCCESS);
             case '?':
             default:
@@ -134,6 +158,8 @@ int parse_options(int argc, char **argv) {
         usage(argv[0], EXIT_FAILURE);
     }
 
+    VERBOSE("Version: " FAKE_HOSTNAME_VERSION "\n");
+
     new_hostname = argv[optind];
     VERBOSE("Faking hostname: %s\n", new_hostname)
     return optind + 1;

src/libfakehostname.c

@@ -13,14 +13,18 @@
 static int (*__orig_gethostname)(char *name, size_t len) = NULL;
 static int (*__orig_uname)(struct utsname *buf) = NULL;
 
+char *version = FAKE_HOSTNAME_VERSION;
+
 #ifdef ENABLE_VERBOSE
     static int verbose = -1;
     #define VERBOSE(...) \
     if (verbose == -1) { \
         verbose = ((getenv(ENV_VARNAME_ENABLE_VERBOSE) == NULL) ? 0 : 1); \
-        if (verbose) \
+        if (verbose) { \
+            fprintf(stderr, "libfakehostname: Version %s\n", version); \
             fprintf(stderr, "libfakehostname: \"" ENV_VARNAME_ENABLE_VERBOSE \
                             "\" set. Enabling verbose mode.\n"); \
+        } \
     } \
     if (verbose) \
         fprintf(stderr, "libfakehostname: " __VA_ARGS__);