Citeren John Crispin <[email protected]>:
On 21/06/18 22:58, Rosen Penev wrote:
error: ‘%d’ directive output may be truncated writing between 2 and 10
bytes into a region of size 3 [-Werror=format-truncation=]
snprintf(fd_buf, sizeof(fd_buf), "%d", wdt_fd);
^~~
note: directive argument in the range [0, 2147483647]
snprintf(fd_buf, sizeof(fd_buf), "%d", wdt_fd);
^~~~~
note: ‘snprintf’ output between 3 and 11 bytes into a destination of size
3
snprintf(fd_buf, sizeof(fd_buf), "%d", wdt_fd);
Signed-off-by: Rosen Penev <[email protected]>
---
watchdog.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/watchdog.c b/watchdog.c
index ec10ba6..efe30f1 100644
--- a/watchdog.c
+++ b/watchdog.c
@@ -144,8 +144,9 @@ char* watchdog_fd(void)
{
static char fd_buf[3];
- if (wdt_fd < 0)
+ if (wdt_fd < 0 || wdt_fd > 99)
return NULL;
+
snprintf(fd_buf, sizeof(fd_buf), "%d", wdt_fd);
imho the %d should be changed to %ld or something similar.
That's not the problem here. The fd_buf is only large enough to store
values between 0 and 99 (inclusive). Although this will fix the
compilation warning/error, I'm slightly worried that this may confuse
callers when the filedescriptor is > 99. Before this patch, you'd get
a truncated value (the first two digits), after there will be no
difference between an error condition (wdt_fd < 0) or a filedescriptor
that is too large to fit in the static fd_buf.
The wdt_fd is defined as an 'int', so %d is appropriate here.
return fd_buf;
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