lguest example launcher truncates block device file to 0 length on problems
The function should also use ftruncate64() rather than ftruncate() to prevent
files over 4GB (not uncommon for a root filesystem) being zeroed.
Signed-off-by: Chris Malley <mail@chrismalley.co.uk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index f791840..73c5f1f 100644
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -882,7 +882,7 @@
* of the block file (possibly extending it). */
if (off + len > device_len) {
/* Trim it back to the correct length */
- ftruncate(dev->fd, device_len);
+ ftruncate64(dev->fd, device_len);
/* Die, bad Guest, die. */
errx(1, "Write past end %llu+%u", off, len);
}