From 2893c5e764557f48f9d6a929e224ed49c59545db Mon Sep 17 00:00:00 2001
From: Darren Tucker <dtucker@dtucker.net>
Date: Fri, 11 Mar 2022 18:43:58 +1100
Subject: [PATCH] Resync fmt_scaled. with OpenBSD.

Fixes underflow reported in bz#3401.
---
 openbsd-compat/fmt_scaled.c | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/openbsd-compat/fmt_scaled.c b/openbsd-compat/fmt_scaled.c
index 2f76ef931..87d40d2d3 100644
--- a/openbsd-compat/fmt_scaled.c
+++ b/openbsd-compat/fmt_scaled.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fmt_scaled.c,v 1.17 2018/05/14 04:39:04 djm Exp $	*/
+/*	$OpenBSD: fmt_scaled.c,v 1.21 2022/03/11 07:29:53 dtucker Exp $	*/
 
 /*
  * Copyright (c) 2001, 2002, 2003 Ian F. Darwin.  All rights reserved.
@@ -54,9 +54,9 @@ typedef enum {
 } unit_type;
 
 /* These three arrays MUST be in sync!  XXX make a struct */
-static unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
-static char scale_chars[] = "BKMGTPE";
-static long long scale_factors[] = {
+static const unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
+static const char scale_chars[] = "BKMGTPE";
+static const long long scale_factors[] = {
 	1LL,
 	1024LL,
 	1024LL*1024,
@@ -153,10 +153,8 @@ scan_scaled(char *scaled, long long *result)
 		}
 	}
 
-	if (sign) {
+	if (sign)
 		whole *= sign;
-		fpart *= sign;
-	}
 
 	/* If no scale factor given, we're done. fraction is discarded. */
 	if (!*p) {
@@ -191,7 +189,8 @@ scan_scaled(char *scaled, long long *result)
 			/* truncate fpart so it doesn't overflow.
 			 * then scale fractional part.
 			 */
-			while (fpart >= LLONG_MAX / scale_fact) {
+			while (fpart >= LLONG_MAX / scale_fact ||
+			    fpart <= LLONG_MIN / scale_fact) {
 				fpart /= 10;
 				fract_digits--;
 			}
@@ -200,7 +199,10 @@ scan_scaled(char *scaled, long long *result)
 				for (i = 0; i < fract_digits -1; i++)
 					fpart /= 10;
 			}
-			whole += fpart;
+			if (sign == -1)
+				whole -= fpart;
+			else
+				whole += fpart;
 			*result = whole;
 			return 0;
 		}
@@ -222,12 +224,16 @@ fmt_scaled(long long number, char *result)
 	unsigned int i;
 	unit_type unit = NONE;
 
+	/* Not every negative long long has a positive representation. */
+	if (number == LLONG_MIN) {
+		errno = ERANGE;
+		return -1;
+	}
+
 	abval = llabs(number);
 
-	/* Not every negative long long has a positive representation.
-	 * Also check for numbers that are just too darned big to format
-	 */
-	if (abval < 0 || abval / 1024 >= scale_factors[SCALE_LENGTH-1]) {
+	/* Also check for numbers that are just too darned big to format. */
+	if (abval / 1024 >= scale_factors[SCALE_LENGTH-1]) {
 		errno = ERANGE;
 		return -1;
 	}