From 956c2a73cd66383d7209d5d3fabea2a6381fa88d Mon Sep 17 00:00:00 2001
From: "George V. Neville-Neil" <gnn@FreeBSD.org>
Date: Tue, 11 Oct 2016 16:12:12 +0000
Subject: [PATCH] Corrected non-portable reuse of va_list in dt_printf()

Submitted by:	Graeme Jenkinson
Reviewed by:	markj
MFC after:	2 weeks
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D8157
---
 .../lib/libdtrace/common/dt_subr.c            | 21 ++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_subr.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_subr.c
index 72fd08aee2c1..2d8c24a0a596 100644
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_subr.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_subr.c
@@ -581,6 +581,7 @@ int
 dt_printf(dtrace_hdl_t *dtp, FILE *fp, const char *format, ...)
 {
 	va_list ap;
+	va_list ap2;
 	int n;
 
 #ifndef illumos
@@ -605,11 +606,13 @@ dt_printf(dtrace_hdl_t *dtp, FILE *fp, const char *format, ...)
 		len = dtp->dt_sprintf_buflen - len;
 		assert(len >= 0);
 
-		if ((n = vsnprintf(buf, len, format, ap)) < 0)
+		va_copy(ap2, ap);
+		if ((n = vsnprintf(buf, len, format, ap2)) < 0)
 			n = dt_set_errno(dtp, errno);
 
+		va_end(ap2);
 		va_end(ap);
-
+		
 		return (n);
 	}
 
@@ -640,11 +643,14 @@ dt_printf(dtrace_hdl_t *dtp, FILE *fp, const char *format, ...)
 			dtp->dt_buffered_buf[0] = '\0';
 		}
 
-		if ((needed = vsnprintf(NULL, 0, format, ap)) < 0) {
+		va_copy(ap2, ap);
+		if ((needed = vsnprintf(NULL, 0, format, ap2)) < 0) {
 			rval = dt_set_errno(dtp, errno);
+			va_end(ap2);
 			va_end(ap);
 			return (rval);
 		}
+		va_end(ap2);
 
 		if (needed == 0) {
 			va_end(ap);
@@ -670,12 +676,15 @@ dt_printf(dtrace_hdl_t *dtp, FILE *fp, const char *format, ...)
 			dtp->dt_buffered_size <<= 1;
 		}
 
+		va_copy(ap2, ap);
 		if (vsnprintf(&dtp->dt_buffered_buf[dtp->dt_buffered_offs],
-		    avail, format, ap) < 0) {
+		    avail, format, ap2) < 0) {
 			rval = dt_set_errno(dtp, errno);
+			va_end(ap2);
 			va_end(ap);
 			return (rval);
 		}
+		va_end(ap2);
 
 		dtp->dt_buffered_offs += needed;
 		assert(dtp->dt_buffered_buf[dtp->dt_buffered_offs] == '\0');
@@ -683,8 +692,10 @@ dt_printf(dtrace_hdl_t *dtp, FILE *fp, const char *format, ...)
 		return (0);
 	}
 
-	n = vfprintf(fp, format, ap);
+	va_copy(ap2, ap);
+	n = vfprintf(fp, format, ap2);
 	fflush(fp);
+	va_end(ap2);
 	va_end(ap);
 
 	if (n < 0) {