losetup: fix wrong printf() format specifier for ino_t data type

Since the range of the ino_t data type is platform-specific (depending on
the wordsize), a usage of the fixed format specifier %PRIu64 is not correct
for ino_t on some 32-bit architectures, eg. ARM (Raspberry Pi 1). This issue
may lead to undefinied output and is not reported by gcc (in version 10.2.0
and 8.3.0-6+rpi1) even though -Wformat is enabled by -Wall. Therefore it is
most likely that it seems to be a false negative error in gcc's format
specifier check, so that this issue was never detected before.

This change fixes the issue by the use of a cast, since there is no
platform-independent format specifier for ino_t available. The wrong format
specifier %PRIu64 is replaced by %ju, where its corresponding variable of
type ino_t is casted to uintmax_t. The type uintmax_t represents the largest
platform-specific unsigned integer, so that all integer values are preserved
for a platform-independent printing.

Fixes: https://github.com/karelzak/util-linux/issues/1211
Signed-off-by: Manuel Bentele <development@manuel-bentele.de>

diff --git a/sys-utils/losetup.c b/sys-utils/losetup.c
index 7aadc9f570ffbb8382c816f36261874ad9febcf9..d94ca4b68b73a3329e68da2ac72ddce5a99f48c2 100644 (file)
--- a/sys-utils/losetup.c
+++ b/sys-utils/losetup.c
@@ -144,8 +144,8 @@ static int printf_loopdev(struct loopdev_cxt *lc)
                goto done;
        }
 
-       printf("%s: [%04d]:%" PRIu64 " (%s)",
-               loopcxt_get_device(lc), (int) dev, ino, fname);
+       printf("%s: [%04jd]:%ju (%s)",
+               loopcxt_get_device(lc), (intmax_t) dev, (uintmax_t) ino, fname);
 
        if (loopcxt_get_offset(lc, &x) == 0 && x)
                        printf(_(", offset %ju"), x);