diff --git a/sub-process.c b/sub-process.c
index 2d5c965169..3cef42b088 100644
--- a/sub-process.c
+++ b/sub-process.c
@@ -49,7 +49,7 @@ int subprocess_read_status(int fd, struct strbuf *status)
 	return (len < 0) ? len : 0;
 }
 
-void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry)
+void subprocess_stop_command(struct subprocess_entry *entry)
 {
 	if (!entry)
 		return;
@@ -57,7 +57,14 @@ void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry)
 	entry->process.clean_on_exit = 0;
 	kill(entry->process.pid, SIGTERM);
 	finish_command(&entry->process);
+}
 
+void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry)
+{
+	if (!entry)
+		return;
+
+	subprocess_stop_command(entry);
 	hashmap_remove(hashmap, &entry->ent, NULL);
 }
 
@@ -72,7 +79,7 @@ static void subprocess_exit_handler(struct child_process *process)
 	finish_command(process);
 }
 
-int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd,
+int subprocess_start_command(struct subprocess_entry *entry, const char *cmd,
 	subprocess_start_fn startfn)
 {
 	int err;
@@ -96,15 +103,26 @@ int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, co
 		return err;
 	}
 
-	hashmap_entry_init(&entry->ent, strhash(cmd));
-
 	err = startfn(entry);
 	if (err) {
 		error("initialization for subprocess '%s' failed", cmd);
-		subprocess_stop(hashmap, entry);
+		subprocess_stop_command(entry);
 		return err;
 	}
 
+	return 0;
+}
+
+int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd,
+	subprocess_start_fn startfn)
+{
+	int err;
+
+	err = subprocess_start_command(entry, cmd, startfn);
+	if (err)
+		return err;
+
+	hashmap_entry_init(&entry->ent, strhash(cmd));
 	hashmap_add(hashmap, &entry->ent);
 	return 0;
 }
diff --git a/sub-process.h b/sub-process.h
index bfc3959a1b..45f1b8e5e3 100644
--- a/sub-process.h
+++ b/sub-process.h
@@ -52,10 +52,17 @@ int cmd2process_cmp(const void *unused_cmp_data,
  */
 typedef int(*subprocess_start_fn)(struct subprocess_entry *entry);
 
-/* Start a subprocess and add it to the subprocess hashmap. */
+/* Start a subprocess and run the startfn (typically handshake). */
+int subprocess_start_command(struct subprocess_entry *entry, const char *cmd,
+		subprocess_start_fn startfn);
+
+/* Start a subprocess, run startfn, and add it to the subprocess hashmap. */
 int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd,
 		subprocess_start_fn startfn);
 
+/* Kill a subprocess. */
+void subprocess_stop_command(struct subprocess_entry *entry);
+
 /* Kill a subprocess and remove it from the subprocess hashmap. */
 void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry);