On Wed, Oct 30, 2024 at 09:50:30PM +0100, Stefano Brivio wrote:
On ppc64le, TUNSETIFF happens to be 2147767498, which
is bigger than
INT_MAX (2^31 - 1), and musl declares the second argument of ioctl()
as 'int', not 'unsigned long' like glibc does, probably because of
how
POSIX specifies the equivalent argument, int dcmd, in posix_devctl(),
so gcc reports a warning:
tap.c: In function 'tap_ns_tun':
tap.c:1291:24: warning: overflow in conversion from 'long unsigned int' to
'int' changes value from '2147767498' to '-2147199798'
[-Woverflow]
1291 | rc = ioctl(fd, TUNSETIFF, &ifr);
| ^~~~~~~~~
We don't care about that overflow, so explicitly cast TUNSETIFF to
int.
Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>
Ugly, but I don't see a better way to deal with it.
Reviewed-by: David Gibson <david(a)gibson.dropbear.id.au>
---
tap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tap.c b/tap.c
index cfb82e9..f638f2c 100644
--- a/tap.c
+++ b/tap.c
@@ -1288,7 +1288,7 @@ static int tap_ns_tun(void *arg)
if (fd < 0)
die_perror("Failed to open() /dev/net/tun");
- rc = ioctl(fd, TUNSETIFF, &ifr);
+ rc = ioctl(fd, (int)TUNSETIFF, &ifr);
if (rc < 0)
die_perror("TUNSETIFF ioctl on /dev/net/tun failed");
--
David Gibson (he or they) | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you, not the other way
| around.
http://www.ozlabs.org/~dgibson