Re: [PATCH] release/checks/integration: handle partial sends

Yureka
2025-11-29T17:27:43Z

Thanks for looking into this.

On 11/29/25 17:35, Alyssa Ross wrote:
> Sometimes we see a test failure that looks like this:
>
> unexpected connection data: qemu-system-aarch64: terminating on signal
> 15 from pid 184 ()
>
> I think this is because, now that the nc command in the networking
> integration test has a timeout, it's possible for it to time out after
> having opened the connection, but before having written all its input
> to it. Therefore, ignore connections that send a prefix of the
> expected data (including nothing), and just wait for the next
> connection rather than failing if that happens.
>
> Closes:
> https://spectrum-os.org/lists/archives/spectrum-devel/875xbl33vw.fsf@alyssa.is/
> Fixes: c61b297 ("release/checks/integration: add nc timeout")
> Signed-off-by: Alyssa Ross <hi@alyssa.is>
> ---
> Please test! It's difficult to know if I've solved the problem for
> real, since it happens transiently.
>
> release/checks/integration/networking.c | 49 +++++++++++++++----------
> 1 file changed, 30 insertions(+), 19 deletions(-)
>
> diff --git a/release/checks/integration/networking.c
> b/release/checks/integration/networking.c
> index 97d7895..a445af1 100644
> --- a/release/checks/integration/networking.c
> +++ b/release/checks/integration/networking.c
> @@ -57,32 +57,43 @@ static int setup_server(void)
> static void expect_connection(int listener)
> {
> - int conn_fd;
> - FILE *conn;
> + int conn, r;
> char msg[7];
> size_t len;
> - fputs("waiting for server connection\n", stderr);
> - if ((conn_fd = accept(listener, nullptr, nullptr)) == -1) {
> - perror("accept");
> - exit(EXIT_FAILURE);
> - }
> - fputs("accepted connection!\n", stderr);
> - if (!(conn = fdopen(conn_fd, "r"))) {
> - perror("fdopen(server connection)");
> - exit(EXIT_FAILURE);
> - }
> + for (;;) {
> + len = 0;
> - len = fread(msg, 1, sizeof msg, conn);
> - if (len != 6 || memcmp("hello\n", msg, 6)) {
> - if (ferror(conn))
> - perror("fread(server connection)");
> - else
> + fputs("waiting for server connection\n", stderr);
> + if ((conn = accept(listener, nullptr, nullptr)) == -1) {
> + perror("accept");
> + exit(EXIT_FAILURE);
> + }
> + fputs("accepted connection!\n", stderr);
> +
> + for (;;) {
> + r = read(conn, msg + len, sizeof msg - len);
> + if (r == -1) {
> + perror("read");
> + exit(EXIT_FAILURE);
> + }
> + if (r == 0)
> + break;
> + len += r;
> + }
> +
> + if (memcmp("hello\n", msg, len) || len > 6) {
> fprintf(stderr, "unexpected connection data: %.*s",
> (int)len, msg);
> - exit(EXIT_FAILURE);
> + exit(EXIT_FAILURE);
> + }
> +
> + // If connection was disconnect partway through, try again.
> + if (len < 6)
> + continue;
> +
> + return;
> }
> - fclose(conn);

Is it intentional that the connection is never closed?

> }
> static void drain_connections(int listener)
>
> base-commit: 067c6a5d50971242f9cb8ac0ac76e20d88a9b5c1