Re: [PATCH v3] repair, passt-repair: Build and warning fixes for musl

[David Gibson <david@gibson.dropbear.id.au>]

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On Sat, Feb 15, 2025 at 12:56:08PM +0100, Stefano Brivio wrote:
> Checked against musl 1.2.5.
> 
> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
> v3: Now 100% more trusted, with cppcheck absolutely positive about us
>     initialising 'buf'.
> 
> v2: Now 100% more tested: don't try to use the whole buffer as
>     msg_controllen.
> 
>  passt-repair.c |  4 +++-
>  repair.c       | 13 +++++++++----
>  2 files changed, 12 insertions(+), 5 deletions(-)
> 
> diff --git a/passt-repair.c b/passt-repair.c
> index 1174ae3..e0c366e 100644
> --- a/passt-repair.c
> +++ b/passt-repair.c
> @@ -63,6 +63,7 @@ int main(int argc, char **argv)
>  	struct cmsghdr *cmsg;
>  	struct msghdr msg;
>  	struct iovec iov;
> +	size_t cmsg_len;
>  	int op;
>  
>  	prctl(PR_SET_DUMPABLE, 0);
> @@ -138,8 +139,9 @@ loop:
>  		}
>  	}
>  	if (!n) {
> +		cmsg_len = cmsg->cmsg_len; /* socklen_t is 'unsigned' on musl */
>  		fprintf(stderr, "Invalid ancillary data length %zu from peer\n",
> -			cmsg->cmsg_len);
> +			cmsg_len);
>  		_exit(1);
>  	}
>  
> diff --git a/repair.c b/repair.c
> index d288617..dac28a6 100644
> --- a/repair.c
> +++ b/repair.c
> @@ -13,6 +13,7 @@
>   */
>  
>  #include <errno.h>
> +#include <sys/socket.h>
>  #include <sys/uio.h>
>  
>  #include "util.h"
> @@ -145,9 +146,9 @@ void repair_handler(struct ctx *c, uint32_t events)
>   */
>  int repair_flush(struct ctx *c)
>  {
> -	struct iovec iov = { &repair_cmd, sizeof(repair_cmd) };
>  	char buf[CMSG_SPACE(sizeof(int) * SCM_MAX_FD)]
> -	     __attribute__ ((aligned(__alignof__(struct cmsghdr))));
> +	     __attribute__ ((aligned(__alignof__(struct cmsghdr)))) = { 0 };
> +	struct iovec iov = { &repair_cmd, sizeof(repair_cmd) };
>  	struct cmsghdr *cmsg;
>  	struct msghdr msg;
>  	int8_t reply;
> @@ -155,8 +156,12 @@ int repair_flush(struct ctx *c)
>  	if (!repair_nfds)
>  		return 0;
>  
> -	msg = (struct msghdr){ NULL, 0, &iov, 1,
> -			       buf, CMSG_SPACE(sizeof(int) * repair_nfds), 0 };
> +	msg = (struct msghdr){ .msg_name = NULL, .msg_namelen = 0,
> +			       .msg_iov = &iov, .msg_iovlen = 1,
> +			       .msg_control = buf,
> +			       .msg_controllen = CMSG_SPACE(sizeof(int) *
> +							    repair_nfds),
> +			       .msg_flags = 0 };
>  	cmsg = CMSG_FIRSTHDR(&msg);
>  
>  	cmsg->cmsg_level = SOL_SOCKET;

-- 
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

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