From: Michal Suchanek <hramrach@gmail.com>
Date: Mon, 27 Jul 2015 13:47:10 +0000 (+0200)
Subject: mtd-utils: mtd_debug: check amount of data read.
X-Git-Tag: v2.0.0-rc1~43
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a2d188795599846bc8f085418467b794881e7209;p=mtd-utils.git

mtd-utils: mtd_debug: check amount of data read.

The kernel refuses to read more data from a MTD device than the device
size. However, mtd_debug does not check the amount of data read as
returned by read(2) and assumes the requested amount is always read when
there is no error. Reading 8M data from a 4M flash chip results in 8M
file containing the flash data at the start.

Signed-off-by: Michal Suchanek <hramrach@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
---

diff --git a/misc-utils/mtd_debug.c b/misc-utils/mtd_debug.c
index d6993ce..f3826cf 100644
--- a/misc-utils/mtd_debug.c
+++ b/misc-utils/mtd_debug.c
@@ -141,7 +141,10 @@ retry:
 			perror("read()");
 			goto err2;
 		}
-		err = write(outfd, buf, size);
+		if (err < size) {
+			fprintf(stderr, "%s: short read, requested %#x, read %#x\n", __func__, size, err);
+		}
+		err = write(outfd, buf, err);
 		if (err < 0) {
 			fprintf(stderr, "%s: write, size %#x, n %#x\n", __func__, size, n);
 			perror("write()");