From 599ae952519138a697b96c369da218f2cf876524 Mon Sep 17 00:00:00 2001
From: topjohnwu <topjohnwu@gmail.com>
Date: Fri, 2 Feb 2018 04:47:16 +0800
Subject: [PATCH] Support moving files across filesystems

---
 native/jni/core/bootstages.c |  2 +-
 native/jni/utils/img.c       | 12 +++++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/native/jni/core/bootstages.c b/native/jni/core/bootstages.c
index 8216c68a2..329272972 100644
--- a/native/jni/core/bootstages.c
+++ b/native/jni/core/bootstages.c
@@ -51,7 +51,7 @@ struct node_entry {
 static void concat_path(struct node_entry *node) {
 	if (node->parent)
 		concat_path(node->parent);
-	int len = strlen(buf);
+	size_t len = strlen(buf);
 	buf[len] = '/';
 	strcpy(buf + len + 1, node->name);
 }
diff --git a/native/jni/utils/img.c b/native/jni/utils/img.c
index cd28b8011..4adabd288 100644
--- a/native/jni/utils/img.c
+++ b/native/jni/utils/img.c
@@ -3,9 +3,11 @@
 
 #include <unistd.h>
 #include <libgen.h>
+#include <fcntl.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <sys/mount.h>
+#include <sys/sendfile.h>
 #include <linux/loop.h>
 
 #include "magisk.h"
@@ -167,7 +169,15 @@ int merge_img(const char *source, const char *target) {
 		return 0;
 	LOGI("* Merging %s  -> %s\n", source, target);
 	if (access(target, F_OK) == -1) {
-		xrename(source, target);
+		if (rename(source, target) < 0) {
+			// Copy and remove
+			int tgt = creat(target, 0644);
+			int src = xopen(source, O_RDONLY | O_CLOEXEC);
+			sendfile(tgt, src, 0, INT_MAX);
+			close(tgt);
+			close(src);
+			unlink(source);
+		}
 		return 0;
 	}