[PATCH] commands: truncate: report errors from ftruncate()

[PATCH] commands: truncate: report errors from ftruncate()

[Ahmad Fatoum]

From: Ahmad Fatoum <a.fatoum@barebox.org>

ftruncate() and fstat() return a negative error code, not -1, so the
command only noticed an -EPERM and otherwise exited with 0 even when the
file wasn't resized, e.g. on a size ubootvarfs has no room for.

Let's check for any negative return value instead.

Fixes: f59a9574c22c ("commands: add new truncate command")
Assisted-by: Claude:opus-5.5
Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
---
 commands/truncate.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/commands/truncate.c b/commands/truncate.c
index 1fd929337dd5..01d827007554 100644
--- a/commands/truncate.c
+++ b/commands/truncate.c
@@ -64,7 +64,7 @@ static int do_truncate(int argc, char *argv[])
 		if (modify) {
 			struct stat st;
 
-			if (fstat(fd, &st) == -1) {
+			if (fstat(fd, &st) < 0) {
 				perror("fstat");
 				ret = 1;
 				close(fd);
@@ -74,7 +74,7 @@ static int do_truncate(int argc, char *argv[])
 			target_size = st.st_size + size;
 		}
 
-		if (ftruncate(fd, target_size) == -1) {
+		if (ftruncate(fd, target_size) < 0) {
 			perror("truncate");
 			ret = 1;
 		}
-- 
2.47.3

Re: [PATCH] commands: truncate: report errors from ftruncate()

[Sascha Hauer]

On Thu, 15 Oct 2026 16:08:11 +0200, Ahmad Fatoum wrote:
> ftruncate() and fstat() return a negative error code, not -1, so the
> command only noticed an -EPERM and otherwise exited with 0 even when the
> file wasn't resized, e.g. on a size ubootvarfs has no room for.
> 
> Let's check for any negative return value instead.
> 
> 
> [...]

Applied, thanks!

[1/1] commands: truncate: report errors from ftruncate()
      https://git.pengutronix.de/cgit/barebox/commit/?id=d9ba097d957d (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>