generator: optionally return resulting unit file path in generator_open_unit_file_full()

This is useful if we want to make symlinks to it later.

src/shared/generator.c

@@ -29,6 +29,7 @@ int generator_open_unit_file_full(
                 const char *source,
                 const char *fn,
                 FILE **ret_file,
+                char **ret_final_path,
                 char **ret_temp_path) {
 
         _cleanup_free_ char *p = NULL;
@@ -72,6 +73,10 @@ int generator_open_unit_file_full(
                 program_invocation_short_name);
 
         *ret_file = f;
+
+        if (ret_final_path)
+                *ret_final_path = TAKE_PTR(p);
+
         return 0;
 }
 

src/shared/generator.h

@@ -6,10 +6,10 @@
 #include "macro.h"
 #include "main-func.h"
 
-int generator_open_unit_file_full(const char *dest, const char *source, const char *name, FILE **ret_file, char **ret_temp_path);
+int generator_open_unit_file_full(const char *dest, const char *source, const char *name, FILE **ret_file, char **ret_final_path, char **ret_temp_path);
 
 static inline int generator_open_unit_file(const char *dest, const char *source, const char *name, FILE **ret_file) {
-        return generator_open_unit_file_full(dest, source, name, ret_file, NULL);
+        return generator_open_unit_file_full(dest, source, name, ret_file, NULL, NULL);
 }
 
 int generator_add_symlink_full(const char *dir, const char *dst, const char *dep_type, const char *src, const char *instance);