tree-wide: introduce PATH_IN_SET macro

src/basic/path-util.c

@@ -569,10 +569,10 @@ static int binary_is_good(const char *binary) {
         if (r < 0)
                 return r;
 
-        return !path_equal(d, "true") &&
-               !path_equal(d, "/bin/true") &&
-               !path_equal(d, "/usr/bin/true") &&
-               !path_equal(d, "/dev/null");
+        return !PATH_IN_SET(d, "true"
+                               "/bin/true",
+                               "/usr/bin/true",
+                               "/dev/null");
 }
 
 int fsck_exists(const char *fstype) {

src/basic/path-util.h

@@ -48,6 +48,19 @@ bool path_equal(const char *a, const char *b) _pure_;
 bool path_equal_or_files_same(const char *a, const char *b);
 char* path_join(const char *root, const char *path, const char *rest);
 
+/* Note: the search terminates on the first NULL item. */
+#define PATH_IN_SET(p, ...)                                     \
+        ({                                                      \
+                char **s;                                       \
+                bool _found = false;                            \
+                STRV_FOREACH(s, STRV_MAKE(__VA_ARGS__))         \
+                        if (path_equal(p, *s)) {                \
+                               _found = true;                   \
+                               break;                           \
+                        }                                       \
+                _found;                                         \
+        })
+
 int path_strv_make_absolute_cwd(char **l);
 char** path_strv_resolve(char **l, const char *prefix);
 char** path_strv_resolve_uniq(char **l, const char *prefix);