Add PS_SYSTEM, the process-level mirror of the thread-level P_SYSTEM,

and FORK_SYSTEM as a flag to set them.  This eliminates needing to
peek into other processes threads in various places.  Inspired by NetBSD

ok miod@ matthew@

7 files changed, 29 insertions, 43 deletions

diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
index eaea6e4d2ab..92481c3308f 100644
--- a/sys/kern/init_main.c
+++ b/sys/kern/init_main.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: init_main.c,v 1.211 2014/04/18 11:51:17 guenther Exp $	*/
+/*	$OpenBSD: init_main.c,v 1.212 2014/05/04 05:03:26 guenther Exp $	*/
 /*	$NetBSD: init_main.c,v 1.84.4.1 1996/06/02 09:08:06 mrg Exp $	*/
 
 /*
@@ -266,6 +266,7 @@ main(void *framep)
 	process0.ps_refcnt = 1;
 	p->p_p = pr = &process0;
 	LIST_INSERT_HEAD(&allprocess, pr, ps_list);
+	atomic_setbits_int(&pr->ps_flags, PS_SYSTEM);
 
 	/* Set the default routing table/domain. */
 	process0.ps_rtableid = 0;
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index da052e891ff..b2ff5552d91 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_fork.c,v 1.164 2014/05/03 22:44:36 guenther Exp $	*/
+/*	$OpenBSD: kern_fork.c,v 1.165 2014/05/04 05:03:26 guenther Exp $	*/
 /*	$NetBSD: kern_fork.c,v 1.29 1996/02/09 18:59:34 christos Exp $	*/
 
 /*
@@ -208,6 +208,8 @@ process_new(struct proc *p, struct process *parent, int flags)
 		atomic_setbits_int(&pr->ps_flags, PS_TRACED);
 	if (flags & FORK_NOZOMBIE)
 		atomic_setbits_int(&pr->ps_flags, PS_NOZOMBIE);
+	if (flags & FORK_SYSTEM)
+		atomic_setbits_int(&pr->ps_flags, PS_SYSTEM);
 
 	/* it's sufficiently inited to be globally visible */
 	LIST_INSERT_HEAD(&allprocess, pr, ps_list);
@@ -236,7 +238,7 @@ fork1(struct proc *curp, int flags, void *stack, pid_t *tidptr,
 
 	/* sanity check some flag combinations */
 	if (flags & FORK_THREAD) {
-		if ((flags & FORK_SIGHAND) == 0)
+		if ((flags & FORK_SIGHAND) == 0 || (flags & FORK_SYSTEM) != 0)
 			return (EINVAL);
 	}
 	if (flags & FORK_SIGHAND && (flags & FORK_SHAREVM) == 0)
@@ -331,6 +333,8 @@ fork1(struct proc *curp, int flags, void *stack, pid_t *tidptr,
 		process_new(p, curpr, flags);
 		pr = p->p_p;
 	}
+	if (pr->ps_flags & PS_SYSTEM)
+		atomic_setbits_int(&p->p_flag, P_SYSTEM);
 
 	/*
 	 * Duplicate sub-structures as needed.
diff --git a/sys/kern/kern_kthread.c b/sys/kern/kern_kthread.c
index 39b7689edb0..8733f82cdb2 100644
--- a/sys/kern/kern_kthread.c
+++ b/sys/kern/kern_kthread.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_kthread.c,v 1.34 2014/02/12 05:47:36 guenther Exp $	*/
+/*	$OpenBSD: kern_kthread.c,v 1.35 2014/05/04 05:03:26 guenther Exp $	*/
 /*	$NetBSD: kern_kthread.c,v 1.3 1998/12/22 21:21:36 kleink Exp $	*/
 
 /*-
@@ -67,15 +67,10 @@ kthread_create(void (*func)(void *), void *arg,
 	 * parent to wait for.
 	 */
 	error = fork1(&proc0, FORK_SHAREVM|FORK_SHAREFILES|FORK_NOZOMBIE|
-	    FORK_SIGHAND, NULL, 0, func, arg, NULL, &p);
+	    FORK_SYSTEM|FORK_SIGHAND, NULL, 0, func, arg, NULL, &p);
 	if (error)
 		return (error);
 
-	/*
-	 * Mark it as a system process.
-	 */
-	atomic_setbits_int(&p->p_flag, P_SYSTEM);
-
 	/* Name it as specified. */
 	strlcpy(p->p_comm, name, sizeof p->p_comm);
 
diff --git a/sys/kern/kern_sched.c b/sys/kern/kern_sched.c
index 1482a3117fa..32e8527d3d0 100644
--- a/sys/kern/kern_sched.c
+++ b/sys/kern/kern_sched.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sched.c,v 1.31 2014/02/12 05:47:36 guenther Exp $	*/
+/*	$OpenBSD: kern_sched.c,v 1.32 2014/05/04 05:03:26 guenther Exp $	*/
 /*
  * Copyright (c) 2007, 2008 Artur Grabowski <art@openbsd.org>
  *
@@ -106,15 +106,10 @@ sched_kthreads_create(void *v)
 	static int num;
 
 	if (fork1(&proc0, FORK_SHAREVM|FORK_SHAREFILES|FORK_NOZOMBIE|
-	    FORK_SIGHAND|FORK_IDLE, NULL, 0, sched_idle, ci, NULL,
+	    FORK_SYSTEM|FORK_SIGHAND|FORK_IDLE, NULL, 0, sched_idle, ci, NULL,
 	    &spc->spc_idleproc))
 		panic("fork idle");
 
-	/*
-	 * Mark it as a system process.
-	 */
-	atomic_setbits_int(&spc->spc_idleproc->p_flag, P_SYSTEM);
-
 	/* Name it as specified. */
 	snprintf(spc->spc_idleproc->p_comm, sizeof(spc->spc_idleproc->p_comm),
 	    "idle%d", num);
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index dd42647a2e6..0c15c8e1477 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sig.c,v 1.165 2014/05/04 03:53:37 deraadt Exp $	*/
+/*	$OpenBSD: kern_sig.c,v 1.166 2014/05/04 05:03:26 guenther Exp $	*/
 /*	$NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $	*/
 
 /*
@@ -618,7 +618,6 @@ sys_kill(struct proc *cp, void *v, register_t *retval)
 int
 killpg1(struct proc *cp, int signum, int pgid, int all)
 {
-	struct proc *p;
 	struct process *pr;
 	struct pgrp *pgrp;
 	int nfound = 0;
@@ -628,13 +627,12 @@ killpg1(struct proc *cp, int signum, int pgid, int all)
 		 * broadcast
 		 */
 		LIST_FOREACH(pr, &allprocess, ps_list) {
-			p = pr->ps_mainproc;
-			if (pr->ps_pid <= 1 || p->p_flag & P_SYSTEM ||
+			if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM ||
 			    pr == cp->p_p || !cansignal(cp, pr, signum))
 				continue;
 			nfound++;
 			if (signum)
-				psignal(p, signum);
+				prsignal(pr, signum);
 		}
 	else {
 		if (pgid == 0)
@@ -648,13 +646,12 @@ killpg1(struct proc *cp, int signum, int pgid, int all)
 				return (ESRCH);
 		}
 		LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) {
-			p = pr->ps_mainproc;
-			if (pr->ps_pid <= 1 || p->p_flag & P_SYSTEM ||
+			if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM ||
 			    !cansignal(cp, pr, signum))
 				continue;
 			nfound++;
-			if (signum && P_ZOMBIE(p) == 0)
-				psignal(p, signum);
+			if (signum)
+				prsignal(pr, signum);
 		}
 	}
 	return (nfound ? 0 : ESRCH);
diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
index 2d07834f844..e1950f3d766 100644
--- a/sys/kern/kern_sysctl.c
+++ b/sys/kern/kern_sysctl.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sysctl.c,v 1.247 2014/05/03 23:30:04 guenther Exp $	*/
+/*	$OpenBSD: kern_sysctl.c,v 1.248 2014/05/04 05:03:26 guenther Exp $	*/
 /*	$NetBSD: kern_sysctl.c,v 1.17 1996/05/20 17:49:05 mrg Exp $	*/
 
 /*-
@@ -1252,7 +1252,7 @@ sysctl_file(int *name, u_int namelen, char *where, size_t *sizep,
 			 * processes
 			 */
 			pp = pr->ps_mainproc;
-			if ((pp->p_flag & P_SYSTEM) || (pr->ps_flags & PS_EXITING)
+			if ((pr->ps_flags & (PS_SYSTEM | PS_EXITING))
 			    || pp->p_stat == SIDL || pp->p_stat == SZOMB)
 				continue;
 			if (arg > 0 && pp->p_pid != (pid_t)arg) {
@@ -1284,7 +1284,7 @@ sysctl_file(int *name, u_int namelen, char *where, size_t *sizep,
 			 * skip system, exiting, embryonic and undead
 			 * processes
 			 */
-			if ((pp->p_flag & P_SYSTEM) || (pr->ps_flags & PS_EXITING)
+			if ((pr->ps_flags & (PS_SYSTEM | PS_EXITING))
 			    || pp->p_stat == SIDL || pp->p_stat == SZOMB)
 				continue;
 			if (arg >= 0 && pp->p_ucred->cr_uid != (uid_t)arg) {
@@ -1418,7 +1418,7 @@ again:
 			break;
 
 		case KERN_PROC_ALL:
-			if (p->p_flag & P_SYSTEM)
+			if (pr->ps_flags & PS_SYSTEM)
 				continue;
 			break;
 
@@ -1584,11 +1584,8 @@ sysctl_proc_args(int *name, u_int namelen, void *oldp, size_t *oldlenp,
 		return (0);
 	}
 
-	if (vp->p_flag & P_SYSTEM)
-		return (EINVAL);
-
-	/* Exiting - don't bother, it will be gone soon anyway */
-	if (vp->p_p->ps_flags & PS_EXITING)
+	/* Either system process or exiting/zombie */
+	if (vp->p_p->ps_flags & (PS_SYSTEM | PS_EXITING))
 		return (EINVAL);
 
 	/* Execing - danger. */
@@ -1774,15 +1771,12 @@ sysctl_proc_cwd(int *name, u_int namelen, void *oldp, size_t *oldlenp,
 		return (0);
 	}
 
-	if (findp->p_flag & P_SYSTEM)
-		return (EINVAL);
-
-	/* Exiting - don't bother, it will be gone soon anyway */
-	if (findp->p_p->ps_flags & PS_EXITING)
+	/* Either system process or exiting/zombie */
+	if (findp->p_p->ps_flags & (PS_SYSTEM | PS_EXITING))
 		return (EINVAL);
 
 	/* Only owner or root can get cwd */
-	if (findp->p_ucred->cr_uid != cp->p_ucred->cr_uid &&
+	if (findp->p_p->ps_ucred->cr_uid != cp->p_ucred->cr_uid &&
 	    (error = suser(cp, 0)) != 0)
 		return (error);
 
diff --git a/sys/kern/sys_process.c b/sys/kern/sys_process.c
index 2500fef5ae7..088d4f35fff 100644
--- a/sys/kern/sys_process.c
+++ b/sys/kern/sys_process.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sys_process.c,v 1.60 2014/03/30 21:54:48 guenther Exp $	*/
+/*	$OpenBSD: sys_process.c,v 1.61 2014/05/04 05:03:26 guenther Exp $	*/
 /*	$NetBSD: sys_process.c,v 1.55 1996/05/15 06:17:47 tls Exp $	*/
 
 /*-
@@ -185,7 +185,7 @@ sys_ptrace(struct proc *p, void *v, register_t *retval)
 		/*
 		 *	(2) it's a system process
 		 */
-		if (ISSET(t->p_flag, P_SYSTEM))
+		if (ISSET(tr->ps_flags, PS_SYSTEM))
 			return (EPERM);
 
 		/*