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From 1957fc6c069493c6789557936adb675f5e7e51ba Mon Sep 17 00:00:00 2001
From: Robert Yang <liezhi.yang@windriver.com>
Date: Wed, 31 Dec 2014 16:43:37 +0800
Subject: [PATCH] linux/syslinux: add ext_file_read() and ext_file_write()
Will use them to read and write on the extX device.
Upstream-Status: Submitted
Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Tested-by: Du Dolpher <dolpher.du@intel.com>
---
linux/syslinux.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 62 insertions(+)
diff --git a/linux/syslinux.c b/linux/syslinux.c
index fc5edb1..c7c1994 100755
--- a/linux/syslinux.c
+++ b/linux/syslinux.c
@@ -350,6 +350,68 @@ fail:
}
+/* Read from an ext2_file */
+static int ext_file_read(ext2_file_t e2_file, void *buf, size_t count,
+ off_t offset, const char *msg)
+{
+ int retval;
+ char *ptr = (char *) buf;
+ unsigned int got = 0;
+ size_t done = 0;
+
+ /* Always lseek since e2_file is uncontrolled by this func */
+ if (ext2fs_file_lseek(e2_file, offset, EXT2_SEEK_SET, NULL)) {
+ fprintf(stderr, "%s: ext2fs_file_lseek() failed.\n",
+ program);
+ return -1;
+ }
+
+ while (1) {
+ retval = ext2fs_file_read(e2_file, ptr, count, &got);
+ if (retval) {
+ fprintf(stderr, "%s: error while reading %s\n",
+ program, msg);
+ return -1;
+ }
+ count -= got;
+ ptr += got;
+ done += got;
+ if (got == 0 || count == 0)
+ break;
+ }
+
+ return done;
+}
+
+/* Write to an ext2_file */
+static int ext_file_write(ext2_file_t e2_file, const void *buf, size_t count,
+ off_t offset)
+{
+ const char *ptr = (const char *) buf;
+ unsigned int written = 0;
+ size_t done = 0;
+
+ /* Always lseek since e2_file is uncontrolled by this func */
+ if (ext2fs_file_lseek(e2_file, offset, EXT2_SEEK_SET, NULL)) {
+ fprintf(stderr, "%s: ext2fs_file_lseek() failed.\n",
+ program);
+ return -1;
+ }
+
+ while (count > 0) {
+ if (ext2fs_file_write(e2_file, ptr, count, &written)) {
+ fprintf(stderr, "%s: failed to write syslinux adv.\n",
+ program);
+ return -1;
+ }
+ count -= written;
+ ptr += written;
+ done += written;
+ }
+
+ return done;
+}
+
/*
* Install the boot block on the specified device.
* Must be run AFTER file installed.
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