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

Alyssa Ross
2025-11-29T16:35:56Z

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);
}

static void drain_connections(int listener)

base-commit: 067c6a5d50971242f9cb8ac0ac76e20d88a9b5c1
--
2.51.0