Re: [PATCH 08/10] selftests/net: SO_PEERPIDFD_THREAD

---
 tools/testing/selftests/net/af_unix/scm_pidfd.c | 97 +++++++++++++++++++++++++
 1 file changed, 97 insertions(+)

diff --git a/tools/testing/selftests/net/af_unix/scm_pidfd.c b/tools/testing/selftests/net/af_unix/scm_pidfd.c
index 019c48e1cdcd..bbbd5e7b4fa7 100644
--- a/tools/testing/selftests/net/af_unix/scm_pidfd.c
+++ b/tools/testing/selftests/net/af_unix/scm_pidfd.c

@@ -32,6 +32,10 @@
 #define SO_PASSPIDFD_THREAD 86
 #endif

+#ifndef SO_PEERPIDFD_THREAD
+#define SO_PEERPIDFD_THREAD 87
+#endif
+
 #define CHILD_EXIT_CODE_OK 123

 static void child_die()

@@ -822,4 +826,97 @@ TEST(scm_pidfd_thread_creds)
        EXPECT_EQ(ids.pid, info.tgid);
 }

+static void *peer_connect_thread(void *arg)
+{
+       struct sock_addr *sa = arg;
+       struct thread_ids ids = {
+               .pid = getpid(),
+               .tid = gettid(),
+       };
+       int fd;
+       char sync;
+
+       fd = socket(AF_UNIX, SOCK_STREAM, 0);
+       if (fd < 0)
+               return (void *)1;
+
+       if (connect(fd, (struct sockaddr *)&sa->listen_addr, sa->addrlen))
+               return (void *)1;
+
+       if (send(fd, &ids, sizeof(ids), 0) != sizeof(ids))
+               return (void *)1;
+
+       /* stay alive until the server has looked at our pidfd */
+       if (read(fd, &sync, 1) != 1)
+               return (void *)1;
+
+       close(fd);
+       return NULL;
+}
+
+static int peer_pidfd_info(int fd, int optname, struct pidfd_info *info)
+{
+       int pidfd;
+       socklen_t len = sizeof(pidfd);
+
+       if (getsockopt(fd, SOL_SOCKET, optname, &pidfd, &len)) {
+               log_err("getsockopt(SO_PEERPIDFD*)");
+               return -1;
+       }
+
+       info->mask = PIDFD_INFO_PID;
+       if (ioctl(pidfd, PIDFD_GET_INFO, info)) {
+               log_err("ioctl(PIDFD_GET_INFO)");
+               close(pidfd);
+               return -1;
+       }
+
+       close(pidfd);
+       return 0;
+}
+
+/* SO_PEERPIDFD_THREAD returns a pidfd for the peer's connecting thread. */
+TEST(so_peerpidfd_thread)
+{
+       struct sock_addr sa;
+       struct thread_ids ids;
+       struct pidfd_info info;
+       pthread_t thread;
+       void *tret;
+       int server, cfd;
+
+       server = socket(AF_UNIX, SOCK_STREAM, 0);
+       ASSERT_LE(0, server);
+
+       fill_sockaddr(&sa, true);
+       ASSERT_EQ(0, bind(server, (struct sockaddr *)&sa.listen_addr, sa.addrlen));
+       ASSERT_EQ(0, listen(server, 1));
+
+       ASSERT_EQ(0, pthread_create(&thread, NULL, peer_connect_thread, &sa));
+
+       cfd = accept(server, NULL, NULL);
+       ASSERT_LE(0, cfd);
+
+       ASSERT_EQ(sizeof(ids), recv(cfd, &ids, sizeof(ids), MSG_WAITALL));
+       ASSERT_NE(ids.pid, ids.tid);
+
+       /* SO_PEERPIDFD refers to the peer's thread-group. */
+       ASSERT_EQ(0, peer_pidfd_info(cfd, SO_PEERPIDFD, &info));
+       EXPECT_EQ(ids.pid, info.pid);
+       EXPECT_EQ(ids.pid, info.tgid);
+
+       /* SO_PEERPIDFD_THREAD refers to the connecting thread. */
+       ASSERT_EQ(0, peer_pidfd_info(cfd, SO_PEERPIDFD_THREAD, &info));
+       EXPECT_EQ(ids.tid, info.pid);
+       EXPECT_EQ(ids.pid, info.tgid);
+
+       /* release the connecting thread */
+       ASSERT_EQ(1, write(cfd, "x", 1));
+       ASSERT_EQ(0, pthread_join(thread, &tret));
+       ASSERT_EQ(NULL, tret);
+
+       close(cfd);
+       close(server);
+}
+
 TEST_HARNESS_MAIN

--

2.53.0