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Reparent a child of pdfork(2) to its reaper when the procdesc is closed.

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Unconditionally reparenting to PID 1 breaks the procctl(2) reaper
functionality.

Add a regression test for this case.

Reviewed by:	kib
Approved by:	re (gjb)
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D17589
This commit is contained in:
Mark Johnston 2018-10-16 20:06:56 +00:00
parent a38abbfb00
commit ddab8c351a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=339390
2 changed files with 44 additions and 7 deletions
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15
sys/kern/sys_procdesc.c
View File

@ -312,8 +312,8 @@ procdesc_exit(struct proc *p)
pd = p->p_procdesc;
PROCDESC_LOCK(pd);
KASSERT((pd->pd_flags & PDF_CLOSED) == 0 || p->p_pptr == initproc,
("procdesc_exit: closed && parent not init"));
KASSERT((pd->pd_flags & PDF_CLOSED) == 0 || p->p_pptr == p->p_reaper,
("procdesc_exit: closed && parent not reaper"));
pd->pd_flags |= PDF_EXITED;
pd->pd_xstat = KW_EXITCODE(p->p_xexit, p->p_xsig);
@ -361,7 +361,8 @@ procdesc_reap(struct proc *p)
/*
* procdesc_close() - last close on a process descriptor. If the process is
* still running, terminate with SIGKILL (unless PDF_DAEMON is set) and let
* init(8) clean up the mess; if not, we have to clean up the zombie ourselves.
* its reaper clean up the mess; if not, we have to clean up the zombie
* ourselves.
*/
static int
procdesc_close(struct file *fp, struct thread *td)
@ -410,12 +411,12 @@ procdesc_close(struct file *fp, struct thread *td)
procdesc_free(pd);
/*
* Next, reparent it to init(8) so that there's someone
* to pick up the pieces; finally, terminate with
* prejudice.
* Next, reparent it to its reaper (usually init(8)) so
* that there's someone to pick up the pieces; finally,
* terminate with prejudice.
*/
p->p_sigparent = SIGCHLD;
proc_reparent(p, initproc);
proc_reparent(p, p->p_reaper);
if ((pd->pd_flags & PDF_DAEMON) == 0)
kern_psignal(p, SIGKILL);
PROC_UNLOCK(p);

36
tests/sys/kern/reaper.c
View File

@ -28,6 +28,7 @@
__FBSDID("$FreeBSD$");
#include <sys/procctl.h>
#include <sys/procdesc.h>
#include <sys/wait.h>
#include <atf-c.h>
@ -740,6 +741,40 @@ ATF_TC_BODY(reaper_kill_subtree, tc)
ATF_REQUIRE_EQ(0, r);
}
ATF_TC_WITHOUT_HEAD(reaper_pdfork);
ATF_TC_BODY(reaper_pdfork, tc)
{
struct procctl_reaper_status st;
pid_t child, grandchild, parent, pid;
int pd, r, status;
parent = getpid();
r = procctl(P_PID, parent, PROC_REAP_ACQUIRE, NULL);
ATF_REQUIRE_EQ(r, 0);
child = pdfork(&pd, 0);
ATF_REQUIRE(child != -1);
if (child == 0) {
grandchild = pdfork(&pd, 0);
if (grandchild == -1)
_exit(1);
if (grandchild == 0)
pause();
_exit(0);
}
pid = waitpid(child, &status, 0);
ATF_REQUIRE_EQ(pid, child);
r = WIFEXITED(status) ? WEXITSTATUS(status) : -1;
ATF_REQUIRE_EQ(r, 0);
r = procctl(P_PID, parent, PROC_REAP_STATUS, &st);
ATF_REQUIRE_EQ(r, 0);
ATF_CHECK((st.rs_flags & REAPER_STATUS_OWNED) != 0);
ATF_CHECK(st.rs_reaper == parent);
ATF_CHECK(st.rs_children == 1);
ATF_CHECK(st.rs_descendants == 1);
}
ATF_TP_ADD_TCS(tp)
{
@ -754,5 +789,6 @@ ATF_TP_ADD_TCS(tp)
ATF_TP_ADD_TC(tp, reaper_kill_empty);
ATF_TP_ADD_TC(tp, reaper_kill_normal);
ATF_TP_ADD_TC(tp, reaper_kill_subtree);
ATF_TP_ADD_TC(tp, reaper_pdfork);
return (atf_no_error());
}