glibc/resolv/ns_makecanon.c

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/* Add missing "." to domain names.
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* Copyright (c) 1995,1999 by Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
#include <arpa/nameser.h>
#include <errno.h>
#include <string.h>
/* Make a canonical copy of domain name SRC in DST. Behavior:
foo -> foo.
foo. -> foo.
foo.. -> foo.
foo\. -> foo\..
foo\\. -> foo\\. */
int
__libc_ns_makecanon (const char *src, char *dst, size_t dstsize)
{
size_t n = strlen (src);
if (n + sizeof "." > dstsize) /* sizeof == 2. */
{
__set_errno (EMSGSIZE);
return -1;
}
strcpy (dst, src);
while (n >= 1U && dst[n - 1] == '.') /* Ends in ".". */
if (n >= 2U && dst[n - 2] == '\\' && /* Ends in "\.". */
(n < 3U || dst[n - 3] != '\\')) /* But not "\\.". */
break;
else
dst[--n] = '\0';
dst[n++] = '.';
dst[n] = '\0';
return 0;
}
libc_hidden_def (__libc_ns_makecanon)