[src/trunk]: src/tests/lib/libc/sys Add a new ATF ptrace(2) test: child_attac...

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

details:   https://anonhg.NetBSD.org/src/rev/82d7ba83f6b6
branches:  trunk
changeset: 365400:82d7ba83f6b6
user:      kamil <kamil%NetBSD.org@localhost>
date:      Mon Aug 13 21:36:55 2018 +0000

description:
Add a new ATF ptrace(2) test: child_attach_to_its_stopped_parent

Reuse the body of child_attach_to_its_parent for a test attaching to a
stopped parent.

As a workaround to ATF framework (atf-run), run this test in a subprocess.
The raise(SIGSTOP) call breaks the pipe from atf-run, that is polling
whether a process is in order.
According to code inspection the poll(2) call in safe_poll() receives
EINTR and this tears down the test.

This test passes.

diffstat:

 tests/lib/libc/sys/t_ptrace_wait.c |  79 ++++++++++++++++++++++++++++++++-----
 1 files changed, 68 insertions(+), 11 deletions(-)

diffs (131 lines):

diff -r 34fa7a5353b2 -r 82d7ba83f6b6 tests/lib/libc/sys/t_ptrace_wait.c
--- a/tests/lib/libc/sys/t_ptrace_wait.c        Mon Aug 13 20:33:35 2018 +0000
+++ b/tests/lib/libc/sys/t_ptrace_wait.c        Mon Aug 13 21:36:55 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: t_ptrace_wait.c,v 1.64 2018/07/17 06:13:08 martin Exp $        */
+/*     $NetBSD: t_ptrace_wait.c,v 1.65 2018/08/13 21:36:55 kamil Exp $ */
 
 /*-
  * Copyright (c) 2016 The NetBSD Foundation, Inc.
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: t_ptrace_wait.c,v 1.64 2018/07/17 06:13:08 martin Exp $");
+__RCSID("$NetBSD: t_ptrace_wait.c,v 1.65 2018/08/13 21:36:55 kamil Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -1429,14 +1429,8 @@
 
 /// ----------------------------------------------------------------------------
 
-ATF_TC(child_attach_to_its_parent);
-ATF_TC_HEAD(child_attach_to_its_parent, tc)
-{
-       atf_tc_set_md_var(tc, "descr",
-           "Assert that tracer child can PT_ATTACH to its parent");
-}
-
-ATF_TC_BODY(child_attach_to_its_parent, tc)
+static void
+child_attach_to_its_parent(bool stopped)
 {
        struct msg_fds parent_tracee;
        const int exitval_tracer = 5;
@@ -1450,10 +1444,15 @@
        SYSCALL_REQUIRE(msg_open(&parent_tracee) == 0);
        tracer = atf_utils_fork();
        if (tracer == 0) {
-
                /* Wait for message from the parent */
                CHILD_FROM_PARENT("Message 1", parent_tracee, msg);
 
+               if (stopped) {
+                       DPRINTF("Await for a stopped parent PID %d\n",
+                               getppid());
+                       await_stopped(getppid());
+               }
+
                DPRINTF("Attach to parent PID %d with PT_ATTACH from child\n",
                    getppid());
                FORKEE_ASSERT(ptrace(PT_ATTACH, getppid(), NULL, 0) != -1);
@@ -1477,6 +1476,12 @@
 
        DPRINTF("Wait for the tracer to become ready\n");
        PARENT_TO_CHILD("Message 1", parent_tracee, msg);
+
+       if (stopped) {
+               DPRINTF("Stop self PID %d\n", getpid());
+               SYSCALL_REQUIRE(raise(SIGSTOP) != -1);
+       }
+
        DPRINTF("Allow the tracer to exit now\n");
        PARENT_FROM_CHILD("Message 1", parent_tracee, msg);
 
@@ -1493,6 +1498,57 @@
        msg_close(&parent_tracee);
 }
 
+ATF_TC(child_attach_to_its_parent);
+ATF_TC_HEAD(child_attach_to_its_parent, tc)
+{
+       atf_tc_set_md_var(tc, "descr",
+           "Assert that tracer child can PT_ATTACH to its parent");
+}
+
+ATF_TC_BODY(child_attach_to_its_parent, tc)
+{
+
+       child_attach_to_its_parent(false);
+}
+
+ATF_TC(child_attach_to_its_stopped_parent);
+ATF_TC_HEAD(child_attach_to_its_stopped_parent, tc)
+{
+       atf_tc_set_md_var(tc, "descr",
+           "Assert that tracer child can PT_ATTACH to its stopped parent");
+}
+
+ATF_TC_BODY(child_attach_to_its_stopped_parent, tc)
+{
+       /*
+        * The ATF framework (atf-run) does not tolerate raise(SIGSTOP), as
+        * this causes a pipe (established from atf-run) to be broken.
+        * atf-run uses this mechanism to monitor whether a test is alive.
+        *
+        * As a workaround spawn this test as a subprocess.
+        */
+
+       const int exitval = 15;
+       pid_t child, wpid;
+#if defined(TWAIT_HAVE_STATUS)
+       int status;
+#endif
+
+       SYSCALL_REQUIRE((child = fork()) != -1);
+       if (child == 0) {
+               child_attach_to_its_parent(true);
+               _exit(exitval);
+       } else {
+               DPRINTF("Before calling %s() for the child\n", TWAIT_FNAME);
+               TWAIT_REQUIRE_SUCCESS(wpid = TWAIT_GENERIC(child, &status, 0), child);
+
+               validate_status_exited(status, exitval);
+
+               DPRINTF("Before calling %s() for the exited child\n", TWAIT_FNAME);
+               TWAIT_REQUIRE_FAILURE(ECHILD, wpid = TWAIT_GENERIC(child, &status, 0));
+       }
+}
+
 /// ----------------------------------------------------------------------------
 
 #if defined(TWAIT_HAVE_PID)
@@ -5616,6 +5672,7 @@
        ATF_TP_ADD_TC(tp, parent_attach_to_its_child);
 
        ATF_TP_ADD_TC(tp, child_attach_to_its_parent);
+       ATF_TP_ADD_TC(tp, child_attach_to_its_stopped_parent);
 
        ATF_TP_ADD_TC_HAVE_PID(tp,
                tracee_sees_its_original_parent_getppid);