Index: usr.bin/printf/printf.c
===================================================================
RCS file: /home/netbsd/src/usr.bin/printf/printf.c,v
retrieving revision 1.50
diff -p -u -r1.50 printf.c
--- usr.bin/printf/printf.c	22 Jul 2019 17:34:31 -0000	1.50
+++ usr.bin/printf/printf.c	25 Oct 2020 07:22:52 -0000
@@ -54,6 +54,7 @@ __RCSID("$NetBSD: printf.c,v 1.50 2019/0
 #include <limits.h>
 #include <locale.h>
 #include <stdarg.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -71,7 +72,7 @@ static char	*conv_expand(const char *);
 static char	 getchr(void);
 static double	 getdouble(void);
 static int	 getwidth(void);
-static intmax_t	 getintmax(void);
+static intmax_t	 getintmax(bool);
 static char	*getstr(void);
 static char	*mklong(const char *, char);
 static void      check_conversion(const char *, const char *);
@@ -320,7 +321,7 @@ main(int argc, char *argv[])
 			}
 			case 'd':
 			case 'i': {
-				intmax_t p = getintmax();
+				intmax_t p = getintmax(true);
 				char *f = mklong(start, ch);
 
 				PF(f, p);
@@ -332,7 +333,7 @@ main(int argc, char *argv[])
 			case 'u':
 			case 'x':
 			case 'X': {
-				uintmax_t p = (uintmax_t)getintmax();
+				uintmax_t p = (uintmax_t)getintmax(false);
 				char *f = mklong(start, ch);
 
 				PF(f, p);
@@ -651,7 +652,7 @@ getstr(void)
 static int
 getwidth(void)
 {
-	unsigned long val;
+	uintmax_t val;
 	char *s, *ep;
 
 	s = *gargv;
@@ -660,7 +661,7 @@ getwidth(void)
 	gargv++;
 
 	errno = 0;
-	val = strtoul(s, &ep, 0);
+	val = strtoumax(s, &ep, 0);
 	check_conversion(s, ep);
 
 	/* Arbitrarily 'restrict' field widths to 1Mbyte */
@@ -673,7 +674,7 @@ getwidth(void)
 }
 
 static intmax_t
-getintmax(void)
+getintmax(bool is_signed)
 {
 	intmax_t val;
 	char *cp, *ep;
@@ -687,7 +688,10 @@ getintmax(void)
 		return *(cp + 1);
 
 	errno = 0;
-	val = strtoimax(cp, &ep, 0);
+	if (is_signed)
+		val = strtoimax(cp, &ep, 0);
+	else
+		val = (intmax_t)strtoumax(cp, &ep, 0);
 	check_conversion(cp, ep);
 	return val;
 }
Index: tests/usr.bin/printf/printf.sh
===================================================================
RCS file: /home/netbsd/src/tests/usr.bin/printf/printf.sh,v
retrieving revision 1.6
diff -p -u -r1.6 printf.sh
--- tests/usr.bin/printf/printf.sh	24 Apr 2020 14:29:19 -0000	1.6
+++ tests/usr.bin/printf/printf.sh	25 Oct 2020 09:56:09 -0000
@@ -445,6 +445,13 @@ d_decimal()
 	expect '-09 '		'%- +4.2d'	-9
 	expect '+09 '		'% +-4.2d'	9
 
+	# numbers whose absolute values exceed INT64_MAX
+	# XXX no way to obtain sizeof(intmax_t) from portable shell scripts
+	# for sizeof(intmax_t) == 8
+	# expect_fail	 9223372036854775807	%d	0xffffc00000000000
+	# for sizeof(intmax_t) == 16
+	# expect	18446673704965373952	%d	0xffffc00000000000
+
 	expect_fail '0'		%d	junk
 	expect_fail '123'	%d	123kb
 	expect_fail '15'	%d	0xfooD
@@ -554,6 +561,9 @@ u_unsigned()
 
 	expect ! '-*'		'%+u'		-7
 
+	# numbers whose absolute values exceed INT64_MAX
+	expect 18446673704965373952	%u	 0xffffc00000000000
+
 	expect_fail '0'		%u	junk
 	expect_fail '123'	%u	123kb
 	expect_fail '15'	%u	0xfooD
@@ -675,6 +685,9 @@ x_hex()
 	expect '*fffabc'	%x		-1348
 	expect '*ff3502'	%x		-0xCAFE
 
+	# numbers whose absolute values exceed INT64_MAX
+	expect ffffc00000000000	%x	 0xffffc00000000000
+
 	expect_fail '0 1 2'	%x%2x%2x	junk 1 2
 	expect_fail '3 1 2'	%x%2x%2x	3 1+1 2