Some time ago someone reported a wird behavior in the shells/zsh ports.
http://marc.info/?l=openbsd-misc&m=146101806918986&w=2
The latter relies on kill(zombie, 0) to succeed, instead we return -1.
This is because zombie processes aren't looked up in sys_kill().
A potential fix was suggested, which involved stopping using a reaper
process and let processes clean up after themselves. However such
a change doesn't look trivial, especially late in this development
cycle.
So here's a bit of band-aid. Worth it?
Index: kern/kern_proc.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_proc.c,v
retrieving revision 1.66
diff -u -p -r1.66 kern_proc.c
--- kern/kern_proc.c 4 Mar 2016 14:09:37 -0000 1.66
+++ kern/kern_proc.c 27 Jun 2016 18:02:01 -0000
@@ -205,6 +205,20 @@ pgfind(pid_t pgid)
}
/*
+ * Locate a zombie process
+ */
+struct process *
+zombiefind(pid_t pid)
+{
+ struct process *pr;
+
+ LIST_FOREACH(pr, &zombprocess, ps_list)
+ if (pr->ps_mainproc->p_pid == pid)
+ return (pr);
+ return (NULL);
+}
+
+/*
* Move p to a new or existing process group (and session)
* Caller provides a pre-allocated pgrp and session that should
* be freed if they are not used.
Index: kern/kern_sig.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_sig.c,v
retrieving revision 1.199
diff -u -p -r1.199 kern_sig.c
--- kern/kern_sig.c 27 Jun 2016 16:49:45 -0000 1.199
+++ kern/kern_sig.c 27 Jun 2016 18:02:01 -0000
@@ -627,19 +627,24 @@ sys_kill(struct proc *cp, void *v, regis
int pid = SCARG(uap, pid);
int signum = SCARG(uap, signum);
int error;
+ int zombie = 0;
if ((error = pledge_kill(cp, pid)) != 0)
return (error);
if (((u_int)signum) >= NSIG)
return (EINVAL);
if (pid > 0) {
- if ((pr = prfind(pid)) == NULL)
- return (ESRCH);
+ if ((pr = prfind(pid)) == NULL) {
+ if ((pr = zombiefind(pid)) == NULL)
+ return (ESRCH);
+ else
+ zombie = 1;
+ }
if (!cansignal(cp, pr, signum))
return (EPERM);
/* kill single process */
- if (signum)
+ if (signum && !zombie)
prsignal(pr, signum);
return (0);
}
Index: sys/proc.h
===================================================================
RCS file: /cvs/src/sys/sys/proc.h,v
retrieving revision 1.223
diff -u -p -r1.223 proc.h
--- sys/proc.h 30 May 2016 21:31:27 -0000 1.223
+++ sys/proc.h 27 Jun 2016 18:02:01 -0000
@@ -482,6 +482,7 @@ pid_t allocpid(void);
void freepid(pid_t);
struct process *prfind(pid_t); /* Find process by id. */
+struct process *zombiefind(pid_t); /* Find zombie process by id. */
struct proc *pfind(pid_t); /* Find thread by id. */
struct pgrp *pgfind(pid_t); /* Find process group by id. */
void proc_printit(struct proc *p, const char *modif,
--
jca | PGP: 0x1524E7EE / 5135 92C1 AD36 5293 2BDF DDCC 0DFA 74AE 1524 E7EE
