Subject: Re: server bind failure 48: Address already in use
To: Caffeinate The World <>
From: Roland Dowdeswell <>
List: current-users
Date: 04/05/2003 14:01:19
On 1049566521 seconds since the Beginning of the UNIX epoch
Caffeinate The World wrote:

>> > /* defensive programming  */
>> >           sprintf(txt,"Chat server bind failure %d: %s\n",errno,
>> > sys_errlist[errno]);
>> Some people will never understand...
>Hi Christian,

He is probably refering to the potential of overflowing the buffer
txt there.  It would be wise to use snprintf(3) or if you are on
a modern unix asprintf(3) rather than sprintf(3).  Also, using
sys_errlist is generally avoided by using strerror(3).

So, something like:

	char *buf;

	asprintf(&buf, "Chat server bind failure %d: %s\n", errno,
	if (buf) {
	return -2;

Would probably be more safe.  If you need to avoid asprintf(3) which is
a slightly new libc function and so may not be available on all the
platforms about which you care then you can use snprintf(3):

	snprintf(buf, sizeof(buf), ...)

And that will truncate the snprintf at the end of the buffer.  Note that
the sizeof(buf) only works if it is declared as an array:

	char buf[1024];

because sizeof() is a compile-time construct.

Of course, depending on what util_printf() does it may be safer to
just use fprintf(3) there.

Hope that helps,

    Roland Dowdeswell                      http://www.Imrryr.ORG/~elric/