[syslinux] [PATCH 4/8] extlinux/main.c: implent ext_read/write_xx_fs()
Robert Yang
liezhi.yang at windriver.com
Wed Dec 24 00:16:11 PST 2014
It uses ext2fs_file_read/write() to reads or write on the ext2_file_t.
Signed-off-by: Robert Yang <liezhi.yang at windriver.com>
---
extlinux/main.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 52 insertions(+), 1 deletion(-)
diff --git a/extlinux/main.c b/extlinux/main.c
index 4205f09..3acf5b5 100644
--- a/extlinux/main.c
+++ b/extlinux/main.c
@@ -996,14 +996,65 @@ static int install_file(const char *path, int devfd, struct stat *rst)
static int ext_read_from_fs(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: ERROR: ext2fs_file_lseek() failed.\n",
+ program);
+ return -1;
+ }
+
+ dprintf("%s: Reading %s\n", program, msg);
+ 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_write_to_fs(ext2_file_t e2_file, const void *buf, size_t count,
off_t offset, const char *msg)
{
-}
+ 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: ERROR: ext2fs_file_lseek() failed.\n",
+ program);
+ return -1;
+ }
+
+ dprintf("%s: writing %s\n", program, msg);
+ while (count > 0) {
+ if (ext2fs_file_write(e2_file, ptr, count, &written)) {
+ fprintf(stderr, "%s: ERROR: failed to write syslinux adv.\n",
+ program);
+ return -1;
+ }
+ count -= written;
+ ptr += written;
+ done += written;
+ }
+
+ return done;
+}
static int write_to_device(ext2_filsys fs, const char *filename,
const char *str, int length, int i_flags,
--
1.9.1
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