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Index: head/sys/kern/kern_exit.c
===================================================================
--- head/sys/kern/kern_exit.c
+++ head/sys/kern/kern_exit.c
@@ -955,7 +955,8 @@
static int
proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id,
- int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo)
+ int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo,
+ int check_only)
{
struct proc *q;
struct rusage *rup;
@@ -1093,7 +1094,7 @@
calccru(p, &rup->ru_utime, &rup->ru_stime);
}
- if (p->p_state == PRS_ZOMBIE) {
+ if (p->p_state == PRS_ZOMBIE && !check_only) {
PROC_SLOCK(p);
proc_reap(td, p, status, options);
return (-1);
@@ -1187,7 +1188,7 @@
sx_xlock(&proctree_lock);
LIST_FOREACH(p, &q->p_children, p_sibling) {
ret = proc_to_reap(td, p, idtype, id, status, options,
- wrusage, siginfo);
+ wrusage, siginfo, 0);
if (ret == 0)
continue;
else if (ret == 1)
@@ -1289,15 +1290,17 @@
* for. By maintaining a list of orphans we allow the parent
* to successfully wait until the child becomes a zombie.
*/
- LIST_FOREACH(p, &q->p_orphans, p_orphan) {
- ret = proc_to_reap(td, p, idtype, id, status, options,
- wrusage, siginfo);
- if (ret == 0)
- continue;
- else if (ret == 1)
- nfound++;
- else
- return (0);
+ if (nfound == 0) {
+ LIST_FOREACH(p, &q->p_orphans, p_orphan) {
+ ret = proc_to_reap(td, p, idtype, id, NULL, options,
+ NULL, NULL, 1);
+ if (ret != 0) {
+ KASSERT(ret != -1, ("reaped an orphan (pid %d)",
+ (int)td->td_retval[0]));
+ nfound++;
+ break;
+ }
+ }
}
if (nfound == 0) {
sx_xunlock(&proctree_lock);
Index: head/tests/sys/kern/ptrace_test.c
===================================================================
--- head/tests/sys/kern/ptrace_test.c
+++ head/tests/sys/kern/ptrace_test.c
@@ -29,6 +29,8 @@
#include <sys/types.h>
#include <sys/ptrace.h>
+#include <sys/sysctl.h>
+#include <sys/user.h>
#include <sys/wait.h>
#include <errno.h>
#include <signal.h>
@@ -133,11 +135,255 @@
ATF_REQUIRE(errno == ECHILD);
}
+/*
+ * Verify that a parent process "sees" the exit of a debugged process only
+ * after the debugger has seen it.
+ */
+ATF_TC_WITHOUT_HEAD(ptrace__parent_sees_exit_after_child_debugger);
+ATF_TC_BODY(ptrace__parent_sees_exit_after_child_debugger, tc)
+{
+ pid_t child, debugger, wpid;
+ int cpipe[2], dpipe[2], status;
+ char c;
+
+ ATF_REQUIRE(pipe(cpipe) == 0);
+ ATF_REQUIRE((child = fork()) != -1);
+
+ if (child == 0) {
+ /* Child process. */
+ close(cpipe[0]);
+
+ /* Wait for parent to be ready. */
+ ATF_REQUIRE(read(cpipe[1], &c, sizeof(c)) == sizeof(c));
+
+ exit(1);
+ }
+ close(cpipe[1]);
+
+ ATF_REQUIRE(pipe(dpipe) == 0);
+ ATF_REQUIRE((debugger = fork()) != -1);
+
+ if (debugger == 0) {
+ /* Debugger process. */
+ close(dpipe[0]);
+
+ ATF_REQUIRE(ptrace(PT_ATTACH, child, NULL, 0) != -1);
+
+ wpid = waitpid(child, &status, 0);
+ ATF_REQUIRE(wpid == child);
+ ATF_REQUIRE(WIFSTOPPED(status));
+ ATF_REQUIRE(WSTOPSIG(status) == SIGSTOP);
+
+ ATF_REQUIRE(ptrace(PT_CONTINUE, child, (caddr_t)1, 0) != -1);
+
+ /* Signal parent that debugger is attached. */
+ ATF_REQUIRE(write(dpipe[1], &c, sizeof(c)) == sizeof(c));
+
+ /* Wait for parent's failed wait. */
+ ATF_REQUIRE(read(dpipe[1], &c, sizeof(c)) == 0);
+
+ wpid = waitpid(child, &status, 0);
+ ATF_REQUIRE(wpid == child);
+ ATF_REQUIRE(WIFEXITED(status));
+ ATF_REQUIRE(WEXITSTATUS(status) == 1);
+
+ exit(0);
+ }
+ close(dpipe[1]);
+
+ /* Parent process. */
+
+ /* Wait for the debugger to attach to the child. */
+ ATF_REQUIRE(read(dpipe[0], &c, sizeof(c)) == sizeof(c));
+
+ /* Release the child. */
+ ATF_REQUIRE(write(cpipe[0], &c, sizeof(c)) == sizeof(c));
+ ATF_REQUIRE(read(cpipe[0], &c, sizeof(c)) == 0);
+ close(cpipe[0]);
+
+ /*
+ * Wait for the child to exit. This is kind of gross, but
+ * there is not a better way.
+ */
+ for (;;) {
+ struct kinfo_proc kp;
+ size_t len;
+ int mib[4];
+
+ mib[0] = CTL_KERN;
+ mib[1] = KERN_PROC;
+ mib[2] = KERN_PROC_PID;
+ mib[3] = child;
+ len = sizeof(kp);
+ if (sysctl(mib, nitems(mib), &kp, &len, NULL, 0) == -1) {
+ /* The KERN_PROC_PID sysctl fails for zombies. */
+ ATF_REQUIRE(errno == ESRCH);
+ break;
+ }
+ usleep(5000);
+ }
+
+ /*
+ * This wait should return an empty pid. The parent should
+ * see the child as non-exited until the debugger sees the
+ * exit.
+ */
+ wpid = waitpid(child, &status, WNOHANG);
+ ATF_REQUIRE(wpid == 0);
+
+ /* Signal the debugger to wait for the child. */
+ close(dpipe[0]);
+
+ /* Wait for the debugger. */
+ wpid = waitpid(debugger, &status, 0);
+ ATF_REQUIRE(wpid == debugger);
+ ATF_REQUIRE(WIFEXITED(status));
+ ATF_REQUIRE(WEXITSTATUS(status) == 0);
+
+ /* The child process should now be ready. */
+ wpid = waitpid(child, &status, WNOHANG);
+ ATF_REQUIRE(wpid == child);
+ ATF_REQUIRE(WIFEXITED(status));
+ ATF_REQUIRE(WEXITSTATUS(status) == 1);
+}
+
+/*
+ * Verify that a parent process "sees" the exit of a debugged process
+ * only after a non-direct-child debugger has seen it. In particular,
+ * various wait() calls in the parent must avoid failing with ESRCH by
+ * checking the parent's orphan list for the debugee.
+ */
+ATF_TC_WITHOUT_HEAD(ptrace__parent_sees_exit_after_unrelated_debugger);
+ATF_TC_BODY(ptrace__parent_sees_exit_after_unrelated_debugger, tc)
+{
+ pid_t child, debugger, fpid, wpid;
+ int cpipe[2], dpipe[2], status;
+ char c;
+
+ ATF_REQUIRE(pipe(cpipe) == 0);
+ ATF_REQUIRE((child = fork()) != -1);
+
+ if (child == 0) {
+ /* Child process. */
+ close(cpipe[0]);
+
+ /* Wait for parent to be ready. */
+ ATF_REQUIRE(read(cpipe[1], &c, sizeof(c)) == sizeof(c));
+
+ exit(1);
+ }
+ close(cpipe[1]);
+
+ ATF_REQUIRE(pipe(dpipe) == 0);
+ ATF_REQUIRE((debugger = fork()) != -1);
+
+ if (debugger == 0) {
+ /* Debugger parent. */
+
+ /*
+ * Fork again and drop the debugger parent so that the
+ * debugger is not a child of the main parent.
+ */
+ ATF_REQUIRE((fpid = fork()) != -1);
+ if (fpid != 0)
+ exit(2);
+
+ /* Debugger process. */
+ close(dpipe[0]);
+
+ ATF_REQUIRE(ptrace(PT_ATTACH, child, NULL, 0) != -1);
+
+ wpid = waitpid(child, &status, 0);
+ ATF_REQUIRE(wpid == child);
+ ATF_REQUIRE(WIFSTOPPED(status));
+ ATF_REQUIRE(WSTOPSIG(status) == SIGSTOP);
+
+ ATF_REQUIRE(ptrace(PT_CONTINUE, child, (caddr_t)1, 0) != -1);
+
+ /* Signal parent that debugger is attached. */
+ ATF_REQUIRE(write(dpipe[1], &c, sizeof(c)) == sizeof(c));
+
+ /* Wait for parent's failed wait. */
+ ATF_REQUIRE(read(dpipe[1], &c, sizeof(c)) == 0);
+
+ wpid = waitpid(child, &status, 0);
+ ATF_REQUIRE(wpid == child);
+ ATF_REQUIRE(WIFEXITED(status));
+ ATF_REQUIRE(WEXITSTATUS(status) == 1);
+
+ exit(0);
+ }
+
+ /* Parent process. */
+
+ /* Wait for the debugger parent process to exit. */
+ wpid = waitpid(debugger, &status, 0);
+ ATF_REQUIRE(wpid == debugger);
+ ATF_REQUIRE(WIFEXITED(status));
+ ATF_REQUIRE(WEXITSTATUS(status) == 2);
+
+ /* A WNOHANG wait here should see the non-exited child. */
+ wpid = waitpid(child, &status, WNOHANG);
+ ATF_REQUIRE(wpid == 0);
+
+ /* Wait for the debugger to attach to the child. */
+ ATF_REQUIRE(read(dpipe[0], &c, sizeof(c)) == sizeof(c));
+
+ /* Release the child. */
+ ATF_REQUIRE(write(cpipe[0], &c, sizeof(c)) == sizeof(c));
+ ATF_REQUIRE(read(cpipe[0], &c, sizeof(c)) == 0);
+ close(cpipe[0]);
+
+ /*
+ * Wait for the child to exit. This is kind of gross, but
+ * there is not a better way.
+ */
+ for (;;) {
+ struct kinfo_proc kp;
+ size_t len;
+ int mib[4];
+
+ mib[0] = CTL_KERN;
+ mib[1] = KERN_PROC;
+ mib[2] = KERN_PROC_PID;
+ mib[3] = child;
+ len = sizeof(kp);
+ if (sysctl(mib, nitems(mib), &kp, &len, NULL, 0) == -1) {
+ /* The KERN_PROC_PID sysctl fails for zombies. */
+ ATF_REQUIRE(errno == ESRCH);
+ break;
+ }
+ usleep(5000);
+ }
+
+ /*
+ * This wait should return an empty pid. The parent should
+ * see the child as non-exited until the debugger sees the
+ * exit.
+ */
+ wpid = waitpid(child, &status, WNOHANG);
+ ATF_REQUIRE(wpid == 0);
+
+ /* Signal the debugger to wait for the child. */
+ close(dpipe[0]);
+
+ /* Wait for the debugger. */
+ ATF_REQUIRE(read(dpipe[1], &c, sizeof(c)) == 0);
+
+ /* The child process should now be ready. */
+ wpid = waitpid(child, &status, WNOHANG);
+ ATF_REQUIRE(wpid == child);
+ ATF_REQUIRE(WIFEXITED(status));
+ ATF_REQUIRE(WEXITSTATUS(status) == 1);
+}
+
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);
+ ATF_TP_ADD_TC(tp, ptrace__parent_sees_exit_after_child_debugger);
+ ATF_TP_ADD_TC(tp, ptrace__parent_sees_exit_after_unrelated_debugger);
return (atf_no_error());
}

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