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[src/trunk]: src/tests/kernel Add new test traceme4 in t_ptrace



details:   https://anonhg.NetBSD.org/src/rev/f64b4e828e64
branches:  trunk
changeset: 818852:f64b4e828e64
user:      kamil <kamil%NetBSD.org@localhost>
date:      Thu Nov 03 11:20:45 2016 +0000

description:
Add new test traceme4 in t_ptrace

This test verifies calling raise(2) with the SIGCONT argument in the child.
The parent is notified with it and asserts that WIFCONTINUED() and
WIFSTOPPED() are both set.

XXX: This behavior is surprising. Linux for the same code-path returns false
for WIFCONTINUED() and true for WIFSTOPPED().

Include <stdlib.h> for EXIT_FAILURE.

This code covers (uncovers issues?) WIFCONTINUED() and is the last planned
test in the ptraceme category.

Sponsored by <The NetBSD Foundation>.

For future reference and convenience, an out-of-ATF test is as follows:
#include <sys/param.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <assert.h>
#include <err.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define ATF_REQUIRE(a) assert(a)

#if defined(linux)
#define WALLSIG __WALL
#define sys_signame sys_siglist
#endif

int main(int argc, char **argv)
{
        int status;
        const int exitval = 5;
        const int sigval = SIGSTOP, sigsent = SIGCONT;
        pid_t child, wpid;

        printf("1: Before forking process PID=%d\n", getpid());
        ATF_REQUIRE((child = fork()) != -1);
        if (child == 0) {
                /* printf(3) messages from a child aren't intercepted by ATF */
                /* "2: Child process PID=%d\n", getpid() */

                /* "2: Before calling ptrace(PT_TRACE_ME, ...)\n" */
                if (ptrace(PT_TRACE_ME, 0, NULL, 0) == -1) {
                        /* XXX: Is it safe to use ATF functions in a child? */
                        err(EXIT_FAILURE, "2: ptrace(2) call failed with "
                            "status %s", sys_errlist[errno]);
                }

                /* "2: Before raising SIGSTOP\n" */
                raise(sigval);

                /* "2: Before raising SIGCONT\n" */
                raise(sigsent);

                /* "2: Before calling _exit(%d)\n", exitval */
                _exit(exitval);
        } else {
                printf("1: Parent process PID=%d, child's PID=%d\n", getpid(),
                    child);

                printf("1: Before calling waitpid() for the child\n");
                wpid = waitpid(child, &status, 0);

                printf("1: Validating child's PID (expected %d, got %d)\n",
                    child, wpid);
                ATF_REQUIRE(child == wpid);

                printf("1: Ensuring that the child has not been exited\n");
                ATF_REQUIRE(!WIFEXITED(status));

                printf("1: Ensuring that the child has not been continued\n");
                ATF_REQUIRE(!WIFCONTINUED(status));

                printf("1: Ensuring that the child has not been terminated "
                    "with a signal\n");
                ATF_REQUIRE(!WIFSIGNALED(status));

                printf("1: Ensuring that the child has been stopped\n");
                ATF_REQUIRE(WIFSTOPPED(status));
                printf("1: Verifying that he child has been stopped with the"
                    " %s signal (received %s)\n", sys_signame[sigval],
                    sys_signame[WSTOPSIG(status)]);
                ATF_REQUIRE(WSTOPSIG(status) == sigval);

                printf("1: Before resuming the child process where it left "
                    "off and without signal to be sent\n");
                ATF_REQUIRE(ptrace(PT_CONTINUE, child, (void *)1, 0)
                    != -1);

                printf("1: Before calling waitpid() for the child\n");
                wpid = waitpid(child, &status, WALLSIG);

                printf("1: Validating that child's PID is still there\n");
                ATF_REQUIRE(wpid == child);

                printf("1: Ensuring that the child has not been exited\n");
                ATF_REQUIRE(!WIFEXITED(status));

                printf("1: Ensuring that the child has been continued\n");
                ATF_REQUIRE(WIFCONTINUED(status));

                printf("1: Ensuring that the child has not been terminated "
                    "with a signal\n");
                ATF_REQUIRE(!WIFSIGNALED(status));

                printf("1: Ensuring that the child has not been stopped\n");
                ATF_REQUIRE(WIFSTOPPED(status));

                printf("1: Before resuming the child process where it left "
                    "off and without signal to be sent\n");
                ATF_REQUIRE(ptrace(PT_CONTINUE, child, (void *)1, 0) != -1);
                printf("1: Before calling waitpid() for the child\n");
                wpid = waitpid(child, &status, 0);

                printf("1: Validating that child's PID is still there\n");
                ATF_REQUIRE(wpid == child);

                printf("1: Ensuring that the child has been exited\n");
                ATF_REQUIRE(WIFEXITED(status));

                printf("1: Ensuring that the child has not been continued\n");
                ATF_REQUIRE(!WIFCONTINUED(status));

                printf("1: Ensuring that the child has not been terminated "
                    "with a signal\n");
                ATF_REQUIRE(!WIFSIGNALED(status));

                printf("1: Ensuring that the child has not been stopped\n");
                ATF_REQUIRE(!WIFSTOPPED(status));

                printf("1: Verifying that he child has exited with the "
                    "%d status (received %d)\n", exitval, WEXITSTATUS(status));
                ATF_REQUIRE(WEXITSTATUS(status) == exitval);

                printf("1: Before calling waitpid() for the exited child\n");
                wpid = waitpid(child, &status, 0);

                printf("1: Validating that child's PID no longer exists\n");
                ATF_REQUIRE(wpid == -1);

                printf("1: Validating that errno is set to %s (got %s)\n",
                    sys_errlist[ECHILD], sys_errlist[errno]);
                ATF_REQUIRE(errno == ECHILD);
        }
}

diffstat:

 tests/kernel/t_ptrace.c |  136 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 134 insertions(+), 2 deletions(-)

diffs (169 lines):

diff -r 3ab424c1a93c -r f64b4e828e64 tests/kernel/t_ptrace.c
--- a/tests/kernel/t_ptrace.c   Thu Nov 03 11:04:21 2016 +0000
+++ b/tests/kernel/t_ptrace.c   Thu Nov 03 11:20:45 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: t_ptrace.c,v 1.3 2016/11/03 08:48:53 kamil Exp $       */
+/*     $NetBSD: t_ptrace.c,v 1.4 2016/11/03 11:20:45 kamil Exp $       */
 
 /*-
  * Copyright (c) 2016 The NetBSD Foundation, Inc.
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: t_ptrace.c,v 1.3 2016/11/03 08:48:53 kamil Exp $");
+__RCSID("$NetBSD: t_ptrace.c,v 1.4 2016/11/03 11:20:45 kamil Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -37,6 +37,7 @@
 #include <errno.h>
 #include <signal.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 
 #include <atf-c.h>
@@ -380,11 +381,142 @@
        }
 }
 
+ATF_TC(traceme4);
+ATF_TC_HEAD(traceme4, tc)
+{
+       atf_tc_set_md_var(tc, "descr",
+           "Verify SIGSTOP followed by SIGCONT and _exit(2) in a child");
+}
+
+ATF_TC_BODY(traceme4, tc)
+{
+       int status;
+       const int exitval = 5;
+       const int sigval = SIGSTOP, sigsent = SIGCONT;
+       pid_t child, wpid;
+
+       printf("1: Before forking process PID=%d\n", getpid());
+       ATF_REQUIRE((child = fork()) != -1);
+       if (child == 0) {
+               /* printf(3) messages from a child aren't intercepted by ATF */
+               /* "2: Child process PID=%d\n", getpid() */
+
+               /* "2: Before calling ptrace(PT_TRACE_ME, ...)\n" */
+               if (ptrace(PT_TRACE_ME, 0, NULL, 0) == -1) {
+                       /* XXX: Is it safe to use ATF functions in a child? */
+                       err(EXIT_FAILURE, "2: ptrace(2) call failed with "
+                           "status %s", sys_errlist[errno]);
+               }
+
+               /* "2: Before raising SIGSTOP\n" */
+               raise(sigval);
+
+               /* "2: Before raising SIGCONT\n" */
+               raise(sigsent);
+
+               /* "2: Before calling _exit(%d)\n", exitval */
+               _exit(exitval);
+       } else {
+               printf("1: Parent process PID=%d, child's PID=%d\n", getpid(),
+                   child);
+
+               printf("1: Before calling waitpid() for the child\n");
+               wpid = waitpid(child, &status, 0);
+
+               printf("1: Validating child's PID (expected %d, got %d)\n",
+                   child, wpid);
+               ATF_REQUIRE(child == wpid);
+
+               printf("1: Ensuring that the child has not been exited\n");
+               ATF_REQUIRE(!WIFEXITED(status));
+
+               printf("1: Ensuring that the child has not been continued\n");
+               ATF_REQUIRE(!WIFCONTINUED(status));
+
+               printf("1: Ensuring that the child has not been terminated "
+                   "with a signal\n");
+               ATF_REQUIRE(!WIFSIGNALED(status));
+
+               printf("1: Ensuring that the child has been stopped\n");
+               ATF_REQUIRE(WIFSTOPPED(status));
+
+               printf("1: Verifying that he child has been stopped with the"
+                   " %s signal (received %s)\n", sys_signame[sigval],
+                   sys_signame[WSTOPSIG(status)]);
+               ATF_REQUIRE(WSTOPSIG(status) == sigval);
+
+               printf("1: Before resuming the child process where it left "
+                   "off and without signal to be sent\n");
+               ATF_REQUIRE(ptrace(PT_CONTINUE, child, (void *)1, 0)
+                   != -1);
+
+               printf("1: Before calling waitpid() for the child\n");
+               wpid = waitpid(child, &status, WALLSIG);
+
+               printf("1: Validating that child's PID is still there\n");
+               ATF_REQUIRE(wpid == child);
+
+               printf("1: Ensuring that the child has not been exited\n");
+               ATF_REQUIRE(!WIFEXITED(status));
+
+               /* XXX: Linux and NetBSD behavior differ here, is it a bug or
+                * a valid result? ptrace(2) is out of POSIX scope so there is
+                * no standard to verify it. */
+               printf("1: Ensuring that the child has been continued\n");
+               ATF_REQUIRE(WIFCONTINUED(status));
+
+               printf("1: Ensuring that the child has not been terminated "
+                   "with a signal\n");
+               ATF_REQUIRE(!WIFSIGNALED(status));
+
+               printf("1: Ensuring that the child has not been stopped\n");
+               ATF_REQUIRE(WIFSTOPPED(status));
+
+               printf("1: Before resuming the child process where it left "
+                   "off and without signal to be sent\n");
+               ATF_REQUIRE(ptrace(PT_CONTINUE, child, (void *)1, 0) != -1);
+
+               printf("1: Before calling waitpid() for the child\n");
+               wpid = waitpid(child, &status, 0);
+
+               printf("1: Validating that child's PID is still there\n");
+               ATF_REQUIRE(wpid == child);
+
+               printf("1: Ensuring that the child has been exited\n");
+               ATF_REQUIRE(WIFEXITED(status));
+
+               printf("1: Ensuring that the child has not been continued\n");
+               ATF_REQUIRE(!WIFCONTINUED(status));
+
+               printf("1: Ensuring that the child has not been terminated "
+                   "with a signal\n");
+               ATF_REQUIRE(!WIFSIGNALED(status));
+
+               printf("1: Ensuring that the child has not been stopped\n");
+               ATF_REQUIRE(!WIFSTOPPED(status));
+
+               printf("1: Verifying that he child has exited with the "
+                   "%d status (received %d)\n", exitval, WEXITSTATUS(status));
+               ATF_REQUIRE(WEXITSTATUS(status) == exitval);
+
+               printf("1: Before calling waitpid() for the exited child\n");
+               wpid = waitpid(child, &status, 0);
+
+               printf("1: Validating that child's PID no longer exists\n");
+               ATF_REQUIRE(wpid == -1);
+
+               printf("1: Validating that errno is set to %s (got %s)\n",
+                   sys_errlist[ECHILD], sys_errlist[errno]);
+               ATF_REQUIRE(errno == ECHILD);
+       }
+}
+
 ATF_TP_ADD_TCS(tp)
 {
        ATF_TP_ADD_TC(tp, traceme1);
        ATF_TP_ADD_TC(tp, traceme2);
        ATF_TP_ADD_TC(tp, traceme3);
+       ATF_TP_ADD_TC(tp, traceme4);
 
        return atf_no_error();
 }



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