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

15 Feb 2025

Checked against musl 1.2.5.

Signed-off-by: Stefano Brivio &lt;sbrivio(a)redhat.com&gt;
---
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;
-- 
2.43.0


    