summaryrefslogtreecommitdiffstats
path: root/tests/sys/file/newfileops_on_fork_test.c
diff options
context:
space:
mode:
Diffstat (limited to 'tests/sys/file/newfileops_on_fork_test.c')
-rw-r--r--tests/sys/file/newfileops_on_fork_test.c121
1 files changed, 121 insertions, 0 deletions
diff --git a/tests/sys/file/newfileops_on_fork_test.c b/tests/sys/file/newfileops_on_fork_test.c
new file mode 100644
index 0000000..8713a82
--- /dev/null
+++ b/tests/sys/file/newfileops_on_fork_test.c
@@ -0,0 +1,121 @@
+/*-
+ * Copyright (c) 2009 Robert N. M. Watson
+ * All rights reserved.
+ *
+ * This software was developed at the University of Cambridge Computer
+ * Laboratory with support from a grant from Google, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * When a multi-threaded application calls fork(2) from one thread while
+ * another thread is blocked in accept(2), we prefer that the file descriptor
+ * to be returned by accept(2) not appear in the child process. Test this by
+ * creating a thread blocked in accept(2), then forking a child and seeing if
+ * the fd it would have returned is defined in the child or not.
+ */
+
+#include <sys/socket.h>
+#include <sys/wait.h>
+
+#include <netinet/in.h>
+
+#include <err.h>
+#include <errno.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define PORT 9000
+
+static int listen_fd;
+
+static void *
+do_accept(__unused void *arg)
+{
+ int accept_fd;
+
+ accept_fd = accept(listen_fd, NULL, NULL);
+ if (accept_fd < 0)
+ err(-1, "accept");
+
+ return (NULL);
+}
+
+static void
+do_fork(void)
+{
+ int pid;
+
+ pid = fork();
+ if (pid < 0)
+ err(-1, "fork");
+ if (pid > 0) {
+ waitpid(pid, NULL, 0);
+ exit(0);
+ }
+
+ /*
+ * We will call ftruncate(2) on the next available file descriptor,
+ * listen_fd+1, and get back EBADF if it's not a valid descriptor,
+ * and EINVAL if it is. This (currently) works fine in practice.
+ */
+ if (ftruncate(listen_fd + 1, 0 < 0)) {
+ if (errno == EBADF)
+ exit(0);
+ else if (errno == EINVAL)
+ errx(-1, "file descriptor still open in child");
+ else
+ err(-1, "unexpected error");
+ } else
+ errx(-1, "ftruncate succeeded");
+}
+
+int
+main(__unused int argc, __unused char *argv[])
+{
+ struct sockaddr_in sin;
+ pthread_t accept_thread;
+
+ listen_fd = socket(PF_INET, SOCK_STREAM, 0);
+ if (listen_fd < 0)
+ err(-1, "socket");
+ bzero(&sin, sizeof(sin));
+ sin.sin_family = AF_INET;
+ sin.sin_len = sizeof(sin);
+ sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+ sin.sin_port = htons(PORT);
+ if (bind(listen_fd, (struct sockaddr *)&sin, sizeof(sin)) < 0)
+ err(-1, "bind");
+ if (listen(listen_fd, -1) <0)
+ err(-1, "listen");
+ if (pthread_create(&accept_thread, NULL, do_accept, NULL) != 0)
+ err(-1, "pthread_create");
+ sleep(1); /* Easier than using a CV. */;
+ do_fork();
+ exit(0);
+}
OpenPOWER on IntegriCloud