From c28aae8bd381f77e66e6bac79761df7a484b054c Mon Sep 17 00:00:00 2001
From: Robert Yang <liezhi.yang@windriver.com>
Date: Fri, 2 Jan 2015 12:28:35 +0800
Subject: [PATCH] linux/syslinux: implement install_bootblock()

Refer to the install_bootblock() in extlinux/main.c to make
linux/syslinux.c's install_bootblock() which only supports ext2/3/4.

Upstream-Status: Submitted

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Tested-by: Du Dolpher <dolpher.du@intel.com>
---
 linux/syslinux.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/linux/syslinux.c b/linux/syslinux.c
index 4e43921..93ed880 100755
--- a/linux/syslinux.c
+++ b/linux/syslinux.c
@@ -420,6 +420,26 @@ static int ext_file_write(ext2_file_t e2_file, const void *buf, size_t count,
  */
 int install_bootblock(int fd, const char *device)
 {
+    struct ext2_super_block sb;
+
+    if (xpread(fd, &sb, sizeof sb, EXT2_SUPER_OFFSET + opt.offset) != sizeof sb) {
+        perror("reading superblock");
+        return 1;
+    }
+
+    if (sb.s_magic != EXT2_SUPER_MAGIC) {
+        fprintf(stderr,
+                "no ext2/3/4 superblock found on %s\n", device);
+        return 1;
+    }
+
+    if (xpwrite(fd, syslinux_bootsect, syslinux_bootsect_len, 0)
+        != (signed)syslinux_bootsect_len) {
+        perror("writing bootblock");
+        return 1;
+    }
+
+    return 0;
 }
 
 /* The file's block count */