basic/glob-util: add helper to strip the glob part from a glob

src/basic/glob-util.c

@@ -71,3 +71,22 @@ int glob_extend(char ***strv, const char *path, int flags) {
 
         return strv_extend_strv(strv, g.gl_pathv, false);
 }
+
+int glob_non_glob_prefix(const char *path, char **ret) {
+        /* Return the path of the path that has no glob characters. */
+
+        size_t n = strcspn(path, GLOB_CHARS);
+
+        if (path[n] != '\0')
+                while (n > 0 && path[n-1] != '/')
+                        n--;
+
+        if (n == 0)
+                return -ENOENT;
+
+        char *ans = strndup(path, n);
+        if (!ans)
+                return -ENOMEM;
+        *ret = ans;
+        return 0;
+}

src/basic/glob-util.h

@@ -13,6 +13,8 @@ int safe_glob(const char *path, int flags, glob_t *pglob);
 int glob_exists(const char *path);
 int glob_extend(char ***strv, const char *path, int flags);
 
+int glob_non_glob_prefix(const char *path, char **ret);
+
 #define _cleanup_globfree_ _cleanup_(globfree)
 
 _pure_ static inline bool string_is_glob(const char *p) {