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Date: Sat, 23 Jun 2001 15:13:10 +0300
From: Peter Pentchev <roam@orbitel.bg>
To: arch@FreeBSD.org
Cc: audit@FreeBSD.org
Subject: patch for '%lld' handling in *scanf(3)
Message-ID: <20010623151310.A497@ringworld.oblivion.bg>
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Hi,

scanf(3) does not understand %lld for 'long long', it only understands
%qd, and it treats %lld as plain %ld.  printf(3) prints out %lld just fine.
The fix needed is just three lines of code, which have been in both NetBSD
and OpenBSD for some time.

Demonstration: the following program:

#include <sys/types.h>
#include <stdio.h>

int
main(void) {
	quad_t x = 0xeFFFFFFFFFFFFFFe;

	scanf("%lld", &x);
	printf("%llx\n", x);
	return (0);
}

Before:

[roam@freefall ~/c/misc/foo]$ ./foo7
5
efffffff00000005
[roam@freefall ~/c/misc/foo]$

After:

[roam@ringworld:v4 ~/c/misc/foo]$ ./foo7
5
5
[roam@ringworld:v4 ~/c/misc/foo]$

The patch is attached.

OK, so maybe this patch is not quite semantically correct; it tends
to assume that 'long long' is the same as 'quad', or at least, that
the programmer asked for 'quad' by using %lld.  A 'real' fix would
be defining a LONGLONG flag for scanf().

G'luck,
Peter

-- 
When you are not looking at it, this sentence is in Spanish.

Index: src/lib/libc/stdio/vfscanf.c
===================================================================
RCS file: /home/ncvs/src/lib/libc/stdio/vfscanf.c,v
retrieving revision 1.16
diff -u -r1.16 vfscanf.c
--- src/lib/libc/stdio/vfscanf.c	2001/02/10 05:46:05	1.16
+++ src/lib/libc/stdio/vfscanf.c	2001/06/23 12:12:30
@@ -186,7 +186,12 @@
 			flags |= SUPPRESS;
 			goto again;
 		case 'l':
-			flags |= LONG;
+			if (*fmt == 'l') {
+				fmt++;
+				flags |= QUAD;
+			} else {
+				flags |= LONG;
+			}
 			goto again;
 		case 'q':
 			flags |= QUAD;

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