Return real parent pid in kinfo (used by e.g. ps)

Add a separate field which exports tracer pid and add a new keyword
("tracer") for ps to display it.

This is a follow up to r270444.

Reviewed by:	kib
MFC after:	1 week
Relnotes:	yes

5 files changed, 20 insertions, 6 deletions

diff --git a/bin/ps/keyword.c b/bin/ps/keyword.c
index 3a0c323..38a9934 100644
--- a/bin/ps/keyword.c
+++ b/bin/ps/keyword.c
@@ -157,6 +157,7 @@ static VAR var[] = {
 	{"tdnam", "TDNAM", NULL, LJUST, tdnam, 0, CHAR, NULL, 0},
 	{"time", "TIME", NULL, USER, cputime, 0, CHAR, NULL, 0},
 	{"tpgid", "TPGID", NULL, 0, kvar, KOFF(ki_tpgid), UINT, PIDFMT, 0},
+	{"tracer", "TRACER", NULL, 0, kvar, KOFF(ki_tracer), UINT, PIDFMT, 0},
 	{"tsid", "TSID", NULL, 0, kvar, KOFF(ki_tsid), UINT, PIDFMT, 0},
 	{"tsiz", "TSIZ", NULL, 0, kvar, KOFF(ki_tsize), PGTOK, "ld", 0},
 	{"tt", "TT ", NULL, 0, tname, 0, CHAR, NULL, 0},
diff --git a/bin/ps/ps.1 b/bin/ps/ps.1
index d8e56fb..294ecf9 100644
--- a/bin/ps/ps.1
+++ b/bin/ps/ps.1
@@ -29,7 +29,7 @@
 .\"     @(#)ps.1	8.3 (Berkeley) 4/18/94
 .\" $FreeBSD$
 .\"
-.Dd August 7, 2014
+.Dd August 27, 2014
 .Dt PS 1
 .Os
 .Sh NAME
@@ -665,6 +665,8 @@ accumulated CPU time, user + system (alias
 .Cm cputime )
 .It Cm tpgid
 control terminal process group ID
+.It Cm tracer
+tracer process ID
 .\".It Cm trss
 .\"text resident set size (in Kbytes)
 .It Cm tsid
diff --git a/sys/compat/freebsd32/freebsd32.h b/sys/compat/freebsd32/freebsd32.h
index 94f886e..155612b 100644
--- a/sys/compat/freebsd32/freebsd32.h
+++ b/sys/compat/freebsd32/freebsd32.h
@@ -343,6 +343,7 @@ struct kinfo_proc32 {
 	char	ki_loginclass[LOGINCLASSLEN+1];
 	char	ki_sparestrings[50];
 	int	ki_spareints[KI_NSPARE_INT];
+	int	ki_tracer;
 	int	ki_flag2;
 	int	ki_fibnum;
 	u_int	ki_cr_flags;
diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index 6689186..740c4a6 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -791,6 +791,8 @@ fill_kinfo_proc_only(struct proc *p, struct kinfo_proc *kp)
 	struct ucred *cred;
 	struct sigacts *ps;
 
+	/* For proc_realparent. */
+	sx_assert(&proctree_lock, SX_LOCKED);
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 	bzero(kp, sizeof(*kp));
 
@@ -920,7 +922,9 @@ fill_kinfo_proc_only(struct proc *p, struct kinfo_proc *kp)
 	kp->ki_acflag = p->p_acflag;
 	kp->ki_lock = p->p_lock;
 	if (p->p_pptr)
-		kp->ki_ppid = p->p_pptr->p_pid;
+		kp->ki_ppid = proc_realparent(p)->p_pid;
+	if (p->p_flag & P_TRACED)
+		kp->ki_tracer = p->p_pptr->p_pid;
 }
 
 /*
@@ -1166,6 +1170,7 @@ freebsd32_kinfo_proc_out(const struct kinfo_proc *ki, struct kinfo_proc32 *ki32)
 	bcopy(ki->ki_comm, ki32->ki_comm, COMMLEN + 1);
 	bcopy(ki->ki_emul, ki32->ki_emul, KI_EMULNAMELEN + 1);
 	bcopy(ki->ki_loginclass, ki32->ki_loginclass, LOGINCLASSLEN + 1);
+	CP(*ki, *ki32, ki_tracer);
 	CP(*ki, *ki32, ki_flag2);
 	CP(*ki, *ki32, ki_fibnum);
 	CP(*ki, *ki32, ki_cr_flags);
@@ -1287,10 +1292,11 @@ sysctl_kern_proc(SYSCTL_HANDLER_ARGS)
 		error = sysctl_wire_old_buffer(req, 0);
 		if (error)
 			return (error);
+		sx_slock(&proctree_lock);
 		error = pget((pid_t)name[0], PGET_CANSEE, &p);
-		if (error != 0)
-			return (error);
-		error = sysctl_out_proc(p, req, flags, 0);
+		if (error == 0)
+			error = sysctl_out_proc(p, req, flags, 0);
+		sx_sunlock(&proctree_lock);
 		return (error);
 	}
 
@@ -1318,6 +1324,7 @@ sysctl_kern_proc(SYSCTL_HANDLER_ARGS)
 	error = sysctl_wire_old_buffer(req, 0);
 	if (error != 0)
 		return (error);
+	sx_slock(&proctree_lock);
 	sx_slock(&allproc_lock);
 	for (doingzomb=0 ; doingzomb < 2 ; doingzomb++) {
 		if (!doingzomb)
@@ -1422,11 +1429,13 @@ sysctl_kern_proc(SYSCTL_HANDLER_ARGS)
 			error = sysctl_out_proc(p, req, flags, doingzomb);
 			if (error) {
 				sx_sunlock(&allproc_lock);
+				sx_sunlock(&proctree_lock);
 				return (error);
 			}
 		}
 	}
 	sx_sunlock(&allproc_lock);
+	sx_sunlock(&proctree_lock);
 	return (0);
 }
 
diff --git a/sys/sys/user.h b/sys/sys/user.h
index f7b18df..6775ff7 100644
--- a/sys/sys/user.h
+++ b/sys/sys/user.h
@@ -84,7 +84,7 @@
  * it in two places: function fill_kinfo_proc in sys/kern/kern_proc.c and
  * function kvm_proclist in lib/libkvm/kvm_proc.c .
  */
-#define	KI_NSPARE_INT	7
+#define	KI_NSPARE_INT	6
 #define	KI_NSPARE_LONG	12
 #define	KI_NSPARE_PTR	6
 
@@ -187,6 +187,7 @@ struct kinfo_proc {
 	 */
 	char	ki_sparestrings[50];	/* spare string space */
 	int	ki_spareints[KI_NSPARE_INT];	/* spare room for growth */
+	int	ki_tracer;		/* Pid of tracing process */
 	int	ki_flag2;		/* P2_* flags */
 	int	ki_fibnum;		/* Default FIB number */
 	u_int	ki_cr_flags;		/* Credential flags */