[U-Boot] [PATCH v2] tools/mkimage: use lseek rather than fstat for file size for -l option

[Peter Korsgaard]

Use lseek rather than fstat for file size for list mode, so
mkimage -l /dev/mtdblockN works (stat returns st_size == 0 for devices).

Notice that you have to use /dev/mtdblockN and not /dev/mtdN, as the
latter doesn't support mmap.

Signed-off-by: Peter Korsgaard <jacmet at sunsite.dk>
---
 tools/mkimage.c |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)

Changes since v1:
 - Incorporate remarks from Thomas/Wolfgang
   (update error message, don't use struct stat)
diff --git a/tools/mkimage.c b/tools/mkimage.c
index b19cd6f..1d4619d 100644
--- a/tools/mkimage.c
+++ b/tools/mkimage.c
@@ -202,23 +202,25 @@ NXTARG:		;
 	}
 
 	if (lflag) {
+		off_t size;
 		/*
 		 * list header information of existing image
 		 */
-		if (fstat(ifd, &sbuf) < 0) {
-			fprintf (stderr, "%s: Can't stat %s: %s\n",
+		size = lseek(ifd, 0, SEEK_END);
+		if (size == (off_t)-1) {
+			fprintf (stderr, "%s: Can't get size of %s: %s\n",
 				cmdname, imagefile, strerror(errno));
 			exit (EXIT_FAILURE);
 		}
 
-		if ((unsigned)sbuf.st_size < image_get_header_size ()) {
+		if ((unsigned)size < image_get_header_size ()) {
 			fprintf (stderr,
 				"%s: Bad size: \"%s\" is no valid image\n",
 				cmdname, imagefile);
 			exit (EXIT_FAILURE);
 		}
 
-		ptr = mmap(0, sbuf.st_size, PROT_READ, MAP_SHARED, ifd, 0);
+		ptr = mmap(0, size, PROT_READ, MAP_SHARED, ifd, 0);
 		if (ptr == MAP_FAILED) {
 			fprintf (stderr, "%s: Can't read %s: %s\n",
 				cmdname, imagefile, strerror(errno));
@@ -227,14 +229,14 @@ NXTARG:		;
 
 		if (fdt_check_header (ptr)) {
 			/* old-style image */
-			image_verify_header ((char *)ptr, sbuf.st_size);
+			image_verify_header ((char *)ptr, size);
 			image_print_contents ((image_header_t *)ptr);
 		} else {
 			/* FIT image */
 			fit_print_contents (ptr);
 		}
 
-		(void) munmap((void *)ptr, sbuf.st_size);
+		(void) munmap((void *)ptr, size);
 		(void) close (ifd);
 
 		exit (EXIT_SUCCESS);
-- 
1.5.6.5