svn commit: r283282 - in head: sys/kern tests/sys/kern
John Baldwin
jhb at FreeBSD.org
Fri May 22 11:04:55 UTC 2015
Author: jhb
Date: Fri May 22 11:04:54 2015
New Revision: 283282
URL: https://svnweb.freebsd.org/changeset/base/283282
Log:
Only reparent a traced process to its old parent if the tracing process is
not the old parent. Otherwise, proc_reap() will leave the zombie in place
resulting in the process' status being returned twice to its parent.
Add test cases for PT_TRACE_ME and PT_ATTACH which are fixed by
this change.
Differential Revision: https://reviews.freebsd.org/D2594
Reviewed by: kib
MFC after: 2 weeks
Added:
head/tests/sys/kern/ptrace_test.c (contents, props changed)
Modified:
head/sys/kern/kern_exit.c
head/tests/sys/kern/Makefile
Modified: head/sys/kern/kern_exit.c
==============================================================================
--- head/sys/kern/kern_exit.c Fri May 22 11:03:51 2015 (r283281)
+++ head/sys/kern/kern_exit.c Fri May 22 11:04:54 2015 (r283282)
@@ -847,13 +847,13 @@ proc_reap(struct thread *td, struct proc
PROC_LOCK(q);
sigqueue_take(p->p_ksi);
PROC_UNLOCK(q);
- PROC_UNLOCK(p);
/*
* If we got the child via a ptrace 'attach', we need to give it back
* to the old parent.
*/
- if (p->p_oppid != 0) {
+ if (p->p_oppid != 0 && p->p_oppid != p->p_pptr->p_pid) {
+ PROC_UNLOCK(p);
t = proc_realparent(p);
PROC_LOCK(t);
PROC_LOCK(p);
@@ -867,6 +867,8 @@ proc_reap(struct thread *td, struct proc
sx_xunlock(&proctree_lock);
return;
}
+ p->p_oppid = 0;
+ PROC_UNLOCK(p);
/*
* Remove other references to this process to ensure we have an
Modified: head/tests/sys/kern/Makefile
==============================================================================
--- head/tests/sys/kern/Makefile Fri May 22 11:03:51 2015 (r283281)
+++ head/tests/sys/kern/Makefile Fri May 22 11:04:54 2015 (r283282)
@@ -3,6 +3,7 @@
TESTSDIR= ${TESTSBASE}/sys/kern
ATF_TESTS_C+= kern_descrip_test
+ATF_TESTS_C+= ptrace_test
ATF_TESTS_C+= unix_seqpacket_test
TEST_METADATA.unix_seqpacket_test+= timeout="15"
Added: head/tests/sys/kern/ptrace_test.c
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ head/tests/sys/kern/ptrace_test.c Fri May 22 11:04:54 2015 (r283282)
@@ -0,0 +1,143 @@
+/*-
+ * Copyright (c) 2015 John Baldwin <jhb at FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <atf-c.h>
+
+/*
+ * Verify that a parent debugger process "sees" the exit of a debugged
+ * process exactly once when attached via PT_TRACE_ME.
+ */
+ATF_TC_WITHOUT_HEAD(ptrace__parent_wait_after_trace_me);
+ATF_TC_BODY(ptrace__parent_wait_after_trace_me, tc)
+{
+ pid_t child, wpid;
+ int status;
+
+ ATF_REQUIRE((child = fork()) != -1);
+ if (child == 0) {
+ /* Child process. */
+ ATF_REQUIRE(ptrace(PT_TRACE_ME, 0, NULL, 0) != -1);
+
+ /* Trigger a stop. */
+ raise(SIGSTOP);
+
+ exit(1);
+ }
+
+ /* Parent process. */
+
+ /* The first wait() should report the stop from SIGSTOP. */
+ wpid = waitpid(child, &status, 0);
+ ATF_REQUIRE(wpid == child);
+ ATF_REQUIRE(WIFSTOPPED(status));
+ ATF_REQUIRE(WSTOPSIG(status) == SIGSTOP);
+
+ /* Continue the child ignoring the SIGSTOP. */
+ ATF_REQUIRE(ptrace(PT_CONTINUE, child, (caddr_t)1, 0) != -1);
+
+ /* The second wait() should report the exit status. */
+ wpid = waitpid(child, &status, 0);
+ ATF_REQUIRE(wpid == child);
+ ATF_REQUIRE(WIFEXITED(status));
+ ATF_REQUIRE(WEXITSTATUS(status) == 1);
+
+ /* The child should no longer exist. */
+ wpid = waitpid(child, &status, 0);
+ ATF_REQUIRE(wpid == -1);
+ ATF_REQUIRE(errno == ECHILD);
+}
+
+/*
+ * Verify that a parent debugger process "sees" the exit of a debugged
+ * process exactly once when attached via PT_ATTACH.
+ */
+ATF_TC_WITHOUT_HEAD(ptrace__parent_wait_after_attach);
+ATF_TC_BODY(ptrace__parent_wait_after_attach, tc)
+{
+ pid_t child, wpid;
+ int cpipe[2], status;
+ char c;
+
+ ATF_REQUIRE(pipe(cpipe) == 0);
+ ATF_REQUIRE((child = fork()) != -1);
+ if (child == 0) {
+ /* Child process. */
+ close(cpipe[0]);
+
+ /* Wait for the parent to attach. */
+ ATF_REQUIRE(read(cpipe[1], &c, sizeof(c)) == 0);
+
+ exit(1);
+ }
+ close(cpipe[1]);
+
+ /* Parent process. */
+
+ /* Attach to the child process. */
+ ATF_REQUIRE(ptrace(PT_ATTACH, child, NULL, 0) == 0);
+
+ /* The first wait() should report the SIGSTOP from PT_ATTACH. */
+ wpid = waitpid(child, &status, 0);
+ ATF_REQUIRE(wpid == child);
+ ATF_REQUIRE(WIFSTOPPED(status));
+ ATF_REQUIRE(WSTOPSIG(status) == SIGSTOP);
+
+ /* Continue the child ignoring the SIGSTOP. */
+ ATF_REQUIRE(ptrace(PT_CONTINUE, child, (caddr_t)1, 0) != -1);
+
+ /* Signal the child to exit. */
+ close(cpipe[0]);
+
+ /* The second wait() should report the exit status. */
+ wpid = waitpid(child, &status, 0);
+ ATF_REQUIRE(wpid == child);
+ ATF_REQUIRE(WIFEXITED(status));
+ ATF_REQUIRE(WEXITSTATUS(status) == 1);
+
+ /* The child should no longer exist. */
+ wpid = waitpid(child, &status, 0);
+ ATF_REQUIRE(wpid == -1);
+ ATF_REQUIRE(errno == ECHILD);
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+
+ ATF_TP_ADD_TC(tp, ptrace__parent_wait_after_trace_me);
+ ATF_TP_ADD_TC(tp, ptrace__parent_wait_after_attach);
+
+ return (atf_no_error());
+}
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