Re: question about change in inet_ntoa.c

Giorgos Keramidas wrote:
On 2008-02-23 02:37, ithilgore <ithilgore.fbsd@xxxxxxxxx> wrote:
ithilgore wrote:
I was looking at the differences between some old FreeBSD code
and the one of 7.0-RC1 and was wondering about a change
in inet_ntoa.c

/***** 7.0-RC1 **************/

sprintf(buf, "%d.%d.%d.%d",
ucp[0] & 0xff,
ucp[1] & 0xff,
ucp[2] & 0xff,
ucp[3] & 0xff);


/****** 4.11-RELEASE ***********/


static const char fmt[] = "%u.%u.%u%u";
if ((size_t)snprintf(dst, size, fmt, src[0], src[1], src[2], src[3])
>= size) {
....
....

Was there a specific purpose of changing the more easy and simple way
of %u instead of the combination of %d and and-ing with 0xff ??
It essentially gives the same result but increases overhead (i think) in the more
recent version.
I just noticed I made a mistake. The second code is libc's version of
inet_ntoa. But the question still counts. Why not use the plain
simpler version of libc ?

I don't see ucp[] in RELENG_6, RELENG_7 or CURRENT. Where did you get
the version shown as `7.0-RC1' above?


I got the source code from the ftp.freebsd.org and I just downloaded 7.0-RC3 to be certain.
Both in 7.0-RC1 and in 7.0-RC3 in src/sys/libkern/ is the following code of inet_ntoa.c :

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/libkern/inet_ntoa.c,v 1.6 2005/01/07 00:24:32 imp Exp $");

#include <sys/param.h>
#include <sys/systm.h>

#include <netinet/in.h>

char *
inet_ntoa(struct in_addr ina)
{
static char buf[4*sizeof "123"];
unsigned char *ucp = (unsigned char *)&ina;

sprintf(buf, "%d.%d.%d.%d",
ucp[0] & 0xff,
ucp[1] & 0xff,
ucp[2] & 0xff,
ucp[3] & 0xff);
return buf;
}

.....followed by the reentrant version of inet_ntoa : inet_ntoa_r


On the other hand, in version 4.11 RELEASE in /usr/src/lib/libc/net/inet_ntoa.c &
inet_ntop.c (actually it is inet_ntop.c code but with the same functionality) which is
called by inet_ntoa there is :

static const char *
inet_ntop4(src, dst, size)
const u_char *src;
char *dst;
size_t size;
{
static const char fmt[] = "%u.%u.%u.%u";

if ((size_t)snprintf(dst, size, fmt, src[0], src[1], src[2], src[3])
>= size) {
errno = ENOSPC;
return (NULL);
}
return (dst);
}






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