From b3a734483e9263c26570003a96701df3d7538048 Mon Sep 17 00:00:00 2001
From: Mariusz Zaborski <oshogbo@FreeBSD.org>
Date: Wed, 8 Jun 2016 02:09:14 +0000
Subject: [PATCH] Introduce the PD_CLOEXEC for pdfork(2).

Reviewed by:	mjg
---
 lib/libc/sys/pdfork.2   |  6 +++++-
 sys/kern/kern_fork.c    |  8 ++++++--
 sys/kern/sys_procdesc.c | 16 ++++++++++++++++
 sys/sys/procdesc.h      |  6 ++++++
 4 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/lib/libc/sys/pdfork.2 b/lib/libc/sys/pdfork.2
index e057f769b89e..5f1a86e3b961 100644
--- a/lib/libc/sys/pdfork.2
+++ b/lib/libc/sys/pdfork.2
@@ -32,7 +32,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd April 7, 2014
+.Dd June 8, 2016
 .Dt PDFORK 2
 .Os
 .Sh NAME
@@ -80,6 +80,10 @@ This option is not permitted in
 capability mode (see
 .Xr cap_enter 2 ) .
 .El
+.Bl -tag -width ".Dv PD_DAEMON"
+.It Dv PD_CLOEXEC
+Set close-on-exec on process descriptor.
+.El
 .Pp
 .Fn pdgetpid
 queries the process ID (PID) in the process descriptor
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index e00409767f75..1260c98e727c 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -827,6 +827,10 @@ fork1(struct thread *td, struct fork_req *fr)
 		/* Must provide a place to put a procdesc if creating one. */
 		if (fr->fr_pd_fd == NULL)
 			return (EINVAL);
+
+		/* Check if we are using supported flags. */
+		if ((fr->fr_pd_flags & ~PD_ALLOWED_AT_FORK) != 0)
+			return (EINVAL);
 	}
 
 	p1 = td->td_proc;
@@ -878,8 +882,8 @@ fork1(struct thread *td, struct fork_req *fr)
 	 * later.
 	 */
 	if (flags & RFPROCDESC) {
-		error = falloc_caps(td, &fp_procdesc, fr->fr_pd_fd, 0,
-		    fr->fr_pd_fcaps);
+		error = procdesc_falloc(td, &fp_procdesc, fr->fr_pd_fd,
+		    fr->fr_pd_flags, fr->fr_pd_fcaps);
 		if (error != 0)
 			goto fail2;
 	}
diff --git a/sys/kern/sys_procdesc.c b/sys/kern/sys_procdesc.c
index 0d3b1f4334bd..37139c1243aa 100644
--- a/sys/kern/sys_procdesc.c
+++ b/sys/kern/sys_procdesc.c
@@ -242,6 +242,22 @@ procdesc_new(struct proc *p, int flags)
 	refcount_init(&pd->pd_refcount, 2);
 }
 
+/*
+ * Create a new process decriptor for the process that refers to it.
+ */
+int
+procdesc_falloc(struct thread *td, struct file **resultfp, int *resultfd,
+    int flags, struct filecaps *fcaps)
+{
+	int fflags;
+
+	fflags = 0;
+	if (flags & PD_CLOEXEC)
+		fflags = O_CLOEXEC;
+
+	return (falloc_caps(td, resultfp, resultfd, fflags, fcaps));
+}
+
 /*
  * Initialize a file with a process descriptor.
  */
diff --git a/sys/sys/procdesc.h b/sys/sys/procdesc.h
index 1a3bc98d1322..a9bad27361b2 100644
--- a/sys/sys/procdesc.h
+++ b/sys/sys/procdesc.h
@@ -101,6 +101,9 @@ void	 procdesc_finit(struct procdesc *, struct file *);
 pid_t	 procdesc_pid(struct file *);
 void	 procdesc_reap(struct proc *);
 
+int	 procdesc_falloc(struct thread *, struct file **, int *, int,
+	    struct filecaps *);
+
 #else /* !_KERNEL */
 
 #include <sys/_types.h>
@@ -127,5 +130,8 @@ __END_DECLS
  * Flags which can be passed to pdfork(2).
  */
 #define	PD_DAEMON	0x00000001	/* Don't exit when procdesc closes. */
+#define	PD_CLOEXEC	0x00000002	/* Close file descriptor on exec. */
+
+#define	PD_ALLOWED_AT_FORK	(PD_DAEMON | PD_CLOEXEC)
 
 #endif /* !_SYS_PROCDESC_H_ */