Add new test attach1 in t_ptrace
This test asserts that tracer sees process termination before the parent Currently this is not true for NetBSD. The problem has been reported in gnats as kern/51600. Originally an early version of this test triggered kernel panic, that was fixed by Christos Zoulas -- thanks! Appropriate fixes are as follows: http://mail-index.netbsd.org/source-changes/2016/11/04/msg078868.html http://mail-index.netbsd.org/source-changes/2016/11/04/msg078869.html Mark this test as expected failure and linked with proper PR. As an interesting note, this test uses pipe(2) to perform IPC. Use for messages uint8_t message to be sure that it will never by transmitted partially from a caller to a callee, this assumption simplifies the code. Add local function await_zombie() that takes process identifier (pid). This function uses the sysctl(7) interface to probe p_stat of a requested process and compares it with LSZOMB. Try to keep closing all unneeded file descriptors for pipes in order to not run out of fds later. Sponsored by <The NetBSD Foundation>.
This commit is contained in:
kamil
parent
b3ba15e2be
commit
b057fe9bfd
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@ -1,4 +1,4 @@
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/* $NetBSD: t_ptrace.c,v 1.8 2016/11/04 09:08:11 kamil Exp $ */
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/* $NetBSD: t_ptrace.c,v 1.9 2016/11/05 01:49:53 kamil Exp $ */
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/*-
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* Copyright (c) 2016 The NetBSD Foundation, Inc.
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@ -27,15 +27,17 @@
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: t_ptrace.c,v 1.8 2016/11/04 09:08:11 kamil Exp $");
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__RCSID("$NetBSD: t_ptrace.c,v 1.9 2016/11/05 01:49:53 kamil Exp $");
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/ptrace.h>
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#include <sys/sysctl.h>
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#include <sys/wait.h>
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#include <err.h>
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#include <errno.h>
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#include <signal.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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@ -68,6 +70,34 @@ do { \
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__FILE__, __LINE__, __func__, #x); \
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} while (0)
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/* This function is currently designed to be run in the main/parent process */
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static void
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await_zombie(pid_t process)
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{
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struct kinfo_proc2 p;
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size_t len = sizeof(p);
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const int name[] = {
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[0] = CTL_KERN,
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[1] = KERN_PROC2,
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[2] = KERN_PROC_PID,
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[3] = process,
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[4] = sizeof(p),
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[5] = 1
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};
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const size_t namelen = __arraycount(name);
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/* Await the process becoming a zombie */
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while(1) {
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ATF_REQUIRE(sysctl(name, namelen, &p, &len, NULL, 0) == 0);
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if (p.p_stat == LSZOMB)
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break;
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ATF_REQUIRE(usleep(1000) == 0);
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}
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}
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ATF_TC(traceme1);
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ATF_TC_HEAD(traceme1, tc)
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@ -467,12 +497,144 @@ ATF_TC_BODY(traceme4, tc)
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ATF_REQUIRE(errno == ECHILD);
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}
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ATF_TC(attach1);
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ATF_TC_HEAD(attach1, tc)
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{
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atf_tc_set_md_var(tc, "descr",
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"Assert that tracer sees process termination before the parent");
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}
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ATF_TC_BODY(attach1, tc)
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{
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int fds_totracee[2], fds_totracer[2], fds_fromtracer[2];
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int status, rv;
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const int exitval_tracee = 5;
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const int exitval_tracer = 10;
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pid_t tracee, tracer, wpid;
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uint8_t msg = 0xde; /* dummy message for IPC based on pipe(2) */
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/* XXX: Linux&FreeBSD and NetBSD have different behavior here.
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* Tracer on NetBSD isn't promoted to observe - before child's parent -
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* that tracee exited (and became zombie).
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*/
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atf_tc_expect_fail("PR kern/51600");
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printf("Spawn tracee\n");
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ATF_REQUIRE(pipe(fds_totracee) == 0);
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ATF_REQUIRE((tracee = fork()) != -1);
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if (tracee == 0) {
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FORKEE_ASSERT(close(fds_totracee[1]) == 0);
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/* Wait for message from the parent */
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rv = read(fds_totracee[0], &msg, sizeof(msg));
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FORKEE_ASSERT(rv == sizeof(msg));
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_exit(exitval_tracee);
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}
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ATF_REQUIRE(close(fds_totracee[0]) == 0);
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printf("Spawn debugger\n");
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ATF_REQUIRE(pipe(fds_totracer) == 0);
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ATF_REQUIRE(pipe(fds_fromtracer) == 0);
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ATF_REQUIRE((tracer = fork()) != -1);
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if (tracer == 0) {
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/* No IPC to communicate with the child */
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FORKEE_ASSERT(close(fds_totracee[1]) == 0);
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FORKEE_ASSERT(close(fds_totracer[1]) == 0);
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FORKEE_ASSERT(close(fds_fromtracer[0]) == 0);
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FORKEE_ASSERT(ptrace(PT_ATTACH, tracee, NULL, 0) != -1);
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/* Wait for tracee and assert that it was stopped w/ SIGSTOP */
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wpid = waitpid(tracee, &status, 0);
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FORKEE_ASSERTX(wpid == tracee);
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FORKEE_ASSERTX(!WIFEXITED(status));
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FORKEE_ASSERTX(!WIFCONTINUED(status));
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FORKEE_ASSERTX(!WIFSIGNALED(status));
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FORKEE_ASSERTX(WIFSTOPPED(status));
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FORKEE_ASSERTX(WSTOPSIG(status) == SIGSTOP);
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/* Resume tracee with PT_CONTINUE */
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FORKEE_ASSERT(ptrace(PT_CONTINUE, tracee, (void *)1, 0) != -1);
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/* Inform parent that tracer has attached to tracee */
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rv = write(fds_fromtracer[1], &msg, sizeof(msg));
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FORKEE_ASSERT(rv == sizeof(msg));
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/* Wait for parent */
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rv = read(fds_totracer[0], &msg, sizeof(msg));
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FORKEE_ASSERT(rv == sizeof(msg));
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/* Wait for tracee and assert that it exited */
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wpid = waitpid(tracee, &status, 0);
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FORKEE_ASSERTX(wpid == tracee);
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FORKEE_ASSERTX(WIFEXITED(status));
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FORKEE_ASSERTX(!WIFCONTINUED(status));
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FORKEE_ASSERTX(!WIFSIGNALED(status));
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FORKEE_ASSERTX(!WIFSTOPPED(status));
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FORKEE_ASSERTX(WEXITSTATUS(status) == exitval_tracee);
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_exit(exitval_tracer);
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}
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ATF_REQUIRE(close(fds_totracer[0]) == 0);
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ATF_REQUIRE(close(fds_fromtracer[1]) == 0);
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printf("Wait for the tracer to attach to the tracee\n");
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rv = read(fds_fromtracer[0], &msg, sizeof(msg));
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ATF_REQUIRE(rv == sizeof(msg));
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printf("Resume the tracee and let it exit\n");
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rv = write(fds_totracee[1], &msg, sizeof(msg));
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ATF_REQUIRE(rv == sizeof(msg));
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printf("fds_totracee is no longer needed - close it\n");
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ATF_REQUIRE(close(fds_totracee[1]) == 0);
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printf("Detect that tracee is zombie\n");
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await_zombie(tracee);
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printf("Assert that there is no status about tracee - "
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"Tracer must detect zombie first\n");
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wpid = waitpid(tracee, &status, WNOHANG);
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ATF_REQUIRE(wpid == 0);
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printf("Resume the tracer and let it detect exited tracee\n");
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rv = write(fds_totracer[1], &msg, sizeof(msg));
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ATF_REQUIRE(rv == sizeof(msg));
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printf("Wait for tracer to finish its job and exit\n");
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wpid = waitpid(tracer, &status, 0);
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ATF_REQUIRE(wpid == tracer);
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ATF_REQUIRE(WIFEXITED(status));
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ATF_REQUIRE(!WIFCONTINUED(status));
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ATF_REQUIRE(!WIFSIGNALED(status));
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ATF_REQUIRE(!WIFSTOPPED(status));
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ATF_REQUIRE(WEXITSTATUS(status) == exitval_tracer);
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printf("Wait for tracer to finish its job and exit\n");
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wpid = waitpid(tracee, &status, WNOHANG);
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ATF_REQUIRE(wpid == tracee);
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ATF_REQUIRE(WIFEXITED(status));
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ATF_REQUIRE(!WIFCONTINUED(status));
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ATF_REQUIRE(!WIFSIGNALED(status));
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ATF_REQUIRE(!WIFSTOPPED(status));
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ATF_REQUIRE(WEXITSTATUS(status) == exitval_tracee);
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printf("fds_fromtracer is no longer needed - close it\n");
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ATF_REQUIRE(close(fds_fromtracer[0]) == 0);
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printf("fds_totracer is no longer needed - close it\n");
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ATF_REQUIRE(close(fds_totracer[1]) == 0);
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}
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ATF_TP_ADD_TCS(tp)
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{
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ATF_TP_ADD_TC(tp, traceme1);
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ATF_TP_ADD_TC(tp, traceme2);
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ATF_TP_ADD_TC(tp, traceme3);
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ATF_TP_ADD_TC(tp, traceme4);
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ATF_TP_ADD_TC(tp, attach1);
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return atf_no_error();
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}
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