From 35d3842cc4b930c5102eed2921e0189b7f4fd069 Mon Sep 17 00:00:00 2001
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From: Robert Yang <liezhi.yang@windriver.com>
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Date: Wed, 31 Dec 2014 16:43:37 +0800
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Subject: [PATCH 4/9] linux/syslinux: add ext_file_read() and ext_file_write()
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Will use them to read and write on the extX device.
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Upstream-Status: Submitted
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Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
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Tested-by: Du Dolpher <dolpher.du@intel.com>
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---
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linux/syslinux.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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1 file changed, 62 insertions(+)
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diff --git a/linux/syslinux.c b/linux/syslinux.c
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index 45f080d..247c86a 100755
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--- a/linux/syslinux.c
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+++ b/linux/syslinux.c
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@@ -349,6 +349,68 @@ fail:
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}
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+/* Read from an ext2_file */
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+static int ext_file_read(ext2_file_t e2_file, void *buf, size_t count,
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+ off_t offset, const char *msg)
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+{
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+ int retval;
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+ char *ptr = (char *) buf;
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+ unsigned int got = 0;
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+ size_t done = 0;
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+
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+ /* Always lseek since e2_file is uncontrolled by this func */
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+ if (ext2fs_file_lseek(e2_file, offset, EXT2_SEEK_SET, NULL)) {
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+ fprintf(stderr, "%s: ext2fs_file_lseek() failed.\n",
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+ program);
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+ return -1;
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+ }
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+
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+ while (1) {
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+ retval = ext2fs_file_read(e2_file, ptr, count, &got);
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+ if (retval) {
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+ fprintf(stderr, "%s: error while reading %s\n",
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+ program, msg);
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+ return -1;
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+ }
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+ count -= got;
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+ ptr += got;
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+ done += got;
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+ if (got == 0 || count == 0)
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+ break;
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+ }
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+
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+ return done;
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+}
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+
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+/* Write to an ext2_file */
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+static int ext_file_write(ext2_file_t e2_file, const void *buf, size_t count,
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+ off_t offset)
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+{
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+ const char *ptr = (const char *) buf;
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+ unsigned int written = 0;
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+ size_t done = 0;
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+
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+ /* Always lseek since e2_file is uncontrolled by this func */
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+ if (ext2fs_file_lseek(e2_file, offset, EXT2_SEEK_SET, NULL)) {
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+ fprintf(stderr, "%s: ext2fs_file_lseek() failed.\n",
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+ program);
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+ return -1;
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+ }
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+
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+ while (count > 0) {
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+ if (ext2fs_file_write(e2_file, ptr, count, &written)) {
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+ fprintf(stderr, "%s: failed to write syslinux adv.\n",
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+ program);
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+ return -1;
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+ }
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+ count -= written;
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+ ptr += written;
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+ done += written;
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+ }
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+
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+ return done;
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+}
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+
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/*
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* Install the boot block on the specified device.
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* Must be run AFTER file installed.
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--
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1.9.1
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