diff --git a/archive.c b/archive.c
index b8b45bad77..75eb257760 100644
--- a/archive.c
+++ b/archive.c
@@ -155,3 +155,21 @@ int write_archive_entries(struct archiver_args *args,
 		err = 0;
 	return err;
 }
+
+int write_archive(int argc, const char **argv, const char *prefix,
+		int setup_prefix)
+{
+	const struct archiver *ar = NULL;
+	struct archiver_args args;
+	int tree_idx;
+
+	tree_idx = parse_archive_args(argc, argv, &ar, &args);
+	if (setup_prefix && prefix == NULL)
+		prefix = setup_git_directory();
+
+	argv += tree_idx;
+	parse_treeish_arg(argv, &args, prefix);
+	parse_pathspec_arg(argv + 1, &args);
+
+	return ar->write_archive(&args);
+}
diff --git a/archive.h b/archive.h
index 4a02371f37..6b5fe5af45 100644
--- a/archive.h
+++ b/archive.h
@@ -41,5 +41,6 @@ extern int write_tar_archive(struct archiver_args *);
 extern int write_zip_archive(struct archiver_args *);
 
 extern int write_archive_entries(struct archiver_args *args, write_archive_entry_fn_t write_entry);
+extern int write_archive(int argc, const char **argv, const char *prefix, int setup_prefix);
 
 #endif	/* ARCHIVE_H */
diff --git a/builtin-archive.c b/builtin-archive.c
index df97724696..502b339e6b 100644
--- a/builtin-archive.c
+++ b/builtin-archive.c
@@ -232,9 +232,6 @@ static const char *extract_remote_arg(int *ac, const char **av)
 
 int cmd_archive(int argc, const char **argv, const char *prefix)
 {
-	const struct archiver *ar = NULL;
-	struct archiver_args args;
-	int tree_idx;
 	const char *remote = NULL;
 
 	remote = extract_remote_arg(&argc, argv);
@@ -243,13 +240,5 @@ int cmd_archive(int argc, const char **argv, const char *prefix)
 
 	setvbuf(stderr, NULL, _IOLBF, BUFSIZ);
 
-	tree_idx = parse_archive_args(argc, argv, &ar, &args);
-	if (prefix == NULL)
-		prefix = setup_git_directory();
-
-	argv += tree_idx;
-	parse_treeish_arg(argv, &args, prefix);
-	parse_pathspec_arg(argv + 1, &args);
-
-	return ar->write_archive(&args);
+	return write_archive(argc, argv, prefix, 1);
 }
diff --git a/builtin-upload-archive.c b/builtin-upload-archive.c
index 13a6c6203e..cc37b36d99 100644
--- a/builtin-upload-archive.c
+++ b/builtin-upload-archive.c
@@ -19,12 +19,9 @@ static const char lostchild[] =
 
 static int run_upload_archive(int argc, const char **argv, const char *prefix)
 {
-	const struct archiver *ar;
-	struct archiver_args args;
 	const char *sent_argv[MAX_ARGS];
 	const char *arg_cmd = "argument ";
 	char *p, buf[4096];
-	int treeish_idx;
 	int sent_argc;
 	int len;
 
@@ -66,12 +63,7 @@ static int run_upload_archive(int argc, const char **argv, const char *prefix)
 	sent_argv[sent_argc] = NULL;
 
 	/* parse all options sent by the client */
-	treeish_idx = parse_archive_args(sent_argc, sent_argv, &ar, &args);
-
-	parse_treeish_arg(sent_argv + treeish_idx, &args, prefix);
-	parse_pathspec_arg(sent_argv + treeish_idx + 1, &args);
-
-	return ar->write_archive(&args);
+	return write_archive(sent_argc, sent_argv, prefix, 0);
 }
 
 static void error_clnt(const char *fmt, ...)