[src/trunk]: src/tests/lib/libc/sys Add a fifo_inout test case that validates...

[thorpej <thorpej%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/7f5825e5c44f
branches:  trunk
changeset: 1023920:7f5825e5c44f
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sat Oct 02 15:50:06 2021 +0000

description:
Add a fifo_inout test case that validates the expected POLLIN / POLLOUT
behavior for FIFOs:
- A FIFO is readable so long as at least 1 byte is available.
- A FIFO is writable so long as at least PIPE_BUF (obtained with _PC_PIPE_BUF)
  space is avaiable.

This will be cloned for a forthcoming kevent test case.

diffstat:

 tests/lib/libc/sys/t_poll.c |  102 +++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 101 insertions(+), 1 deletions(-)

diffs (130 lines):

diff -r f632cfdffa1f -r 7f5825e5c44f tests/lib/libc/sys/t_poll.c
--- a/tests/lib/libc/sys/t_poll.c       Sat Oct 02 14:41:36 2021 +0000
+++ b/tests/lib/libc/sys/t_poll.c       Sat Oct 02 15:50:06 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: t_poll.c,v 1.6 2021/10/02 14:41:36 thorpej Exp $       */
+/*     $NetBSD: t_poll.c,v 1.7 2021/10/02 15:50:06 thorpej Exp $       */
 
 /*-
  * Copyright (c) 2011 The NetBSD Foundation, Inc.
@@ -39,6 +39,7 @@
 #include <paths.h>
 #include <poll.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <signal.h>
 #include <unistd.h>
 
@@ -252,6 +253,104 @@
        }
 }
 
+ATF_TC_WITH_CLEANUP(fifo_inout);
+ATF_TC_HEAD(fifo_inout, tc)
+{
+       atf_tc_set_md_var(tc, "descr",
+           "Check POLLIN/POLLOUT behavior with fifos");
+}
+
+ATF_TC_BODY(fifo_inout, tc)
+{
+       struct pollfd pfd[2];
+       char *buf;
+       int rfd, wfd;
+       long pipe_buf;
+
+       fifo_support();
+
+       ATF_REQUIRE(mkfifo(fifo_path, 0600) == 0);
+       ATF_REQUIRE((rfd = open(fifo_path, O_RDONLY | O_NONBLOCK)) >= 0);
+       ATF_REQUIRE((wfd = open(fifo_path, O_WRONLY | O_NONBLOCK)) >= 0);
+
+       /* Get the maximum atomic pipe write size. */
+       pipe_buf = fpathconf(wfd, _PC_PIPE_BUF);
+       ATF_REQUIRE(pipe_buf > 1);
+
+       buf = malloc(pipe_buf);
+       ATF_REQUIRE(buf != NULL);
+
+       memset(&pfd, 0, sizeof(pfd));
+       pfd[0].fd = rfd;
+       pfd[0].events = POLLIN | POLLRDNORM;
+       pfd[1].fd = wfd;
+       pfd[1].events = POLLOUT | POLLWRNORM;
+
+       /* We expect the FIFO to be writable but not readable. */
+       ATF_REQUIRE(poll(pfd, 2, 0) == 1);
+       ATF_REQUIRE(pfd[0].revents == 0);
+       ATF_REQUIRE(pfd[1].revents == (POLLOUT | POLLWRNORM));
+
+       /* Write a single byte of data into the FIFO. */
+       ATF_REQUIRE(write(wfd, buf, 1) == 1);
+
+       /* We expect the FIFO to be readable and writable. */
+       ATF_REQUIRE(poll(pfd, 2, 0) == 2);
+       ATF_REQUIRE(pfd[0].revents == (POLLIN | POLLRDNORM));
+       ATF_REQUIRE(pfd[1].revents == (POLLOUT | POLLWRNORM));
+
+       /* Read that single byte back out. */
+       ATF_REQUIRE(read(rfd, buf, 1) == 1);
+
+       /*
+        * Write data into the FIFO until it is full, which is
+        * defined as insufficient buffer space to hold a the
+        * maximum atomic pipe write size.
+        */
+       while (write(wfd, buf, pipe_buf) != -1) {
+               continue;
+       }
+       ATF_REQUIRE(errno == EAGAIN);
+
+       /* We expect the FIFO to be readble but not writable. */
+       ATF_REQUIRE(poll(pfd, 2, 0) == 1);
+       ATF_REQUIRE(pfd[0].revents == (POLLIN | POLLRDNORM));
+       ATF_REQUIRE(pfd[1].revents == 0);
+
+       /* Read a single byte of data from the FIFO. */
+       ATF_REQUIRE(read(rfd, buf, 1) == 1);
+
+       /*
+        * Because we have read only a single byte out, there will
+        * be insufficient space for a pipe_buf-sized message, so
+        * the FIFO should still not be writable.
+        */
+       ATF_REQUIRE(poll(pfd, 2, 0) == 1);
+       ATF_REQUIRE(pfd[0].revents == (POLLIN | POLLRDNORM));
+       ATF_REQUIRE(pfd[1].revents == 0);
+
+       /*
+        * Now read all of the data out of the FIFO and ensure that
+        * we get back to the initial state.
+        */
+       while (read(rfd, buf, pipe_buf) != -1) {
+               continue;
+       }
+       ATF_REQUIRE(errno == EAGAIN);
+
+       ATF_REQUIRE(poll(pfd, 2, 0) == 1);
+       ATF_REQUIRE(pfd[0].revents == 0);
+       ATF_REQUIRE(pfd[1].revents == (POLLOUT | POLLWRNORM));
+
+       (void)close(wfd);
+       (void)close(rfd);
+}
+
+ATF_TC_CLEANUP(fifo_inout, tc)
+{
+       (void)unlink(fifo_path);
+}
+
 ATF_TC_WITH_CLEANUP(fifo_hup1);
 ATF_TC_HEAD(fifo_hup1, tc)
 {
@@ -354,6 +453,7 @@
        ATF_TP_ADD_TC(tp, basic);
        ATF_TP_ADD_TC(tp, err);
 
+       ATF_TP_ADD_TC(tp, fifo_inout);
        ATF_TP_ADD_TC(tp, fifo_hup1);
        ATF_TP_ADD_TC(tp, fifo_hup2);