11556Srgrimes/*
21556Srgrimes * Copyright (c) 2000-2001 Proofpoint, Inc. and its suppliers.
31556Srgrimes *      All rights reserved.
41556Srgrimes * Copyright (c) 1990, 1993
51556Srgrimes *	The Regents of the University of California.  All rights reserved.
61556Srgrimes *
71556Srgrimes * This code is derived from software contributed to Berkeley by
81556Srgrimes * Chris Torek.
91556Srgrimes *
101556Srgrimes * By using this file, you agree to the terms and conditions set
111556Srgrimes * forth in the LICENSE file which can be found at the top level of
121556Srgrimes * the sendmail distribution.
131556Srgrimes */
141556Srgrimes
151556Srgrimes#include <sm/gen.h>
161556SrgrimesSM_RCSID("@(#)$Id: vsnprintf.c,v 1.24 2013-11-22 20:51:44 ca Exp $")
171556Srgrimes#include <limits.h>
181556Srgrimes#include <sm/io.h>
191556Srgrimes#include "local.h"
201556Srgrimes
211556Srgrimes/*
221556Srgrimes**  SM_VSNPRINTF -- format data for "output" into a string
231556Srgrimes**
241556Srgrimes**	Assigned 'str' to a "fake" file pointer. This allows common
251556Srgrimes**	o/p formatting function sm_vprintf() to be used.
261556Srgrimes**
271556Srgrimes**	Parameters:
281556Srgrimes**		str -- location for output
291556Srgrimes**		n -- maximum size for o/p
301556Srgrimes**		fmt -- format directives
311556Srgrimes**		ap -- data unit vectors for use by 'fmt'
321556Srgrimes**
331556Srgrimes**	Results:
341556Srgrimes**		result from sm_io_vfprintf()
351556Srgrimes**
361556Srgrimes**	Side Effects:
371556Srgrimes**		Limits the size ('n') to INT_MAX.
3850471Speter*/
391556Srgrimes
401556Srgrimesint
411556Srgrimessm_vsnprintf(str, n, fmt, ap)
421556Srgrimes	char *str;
431556Srgrimes	size_t n;
441556Srgrimes	const char *fmt;
451556Srgrimes	va_list ap;
461556Srgrimes{
471556Srgrimes	int ret;
4846684Skris	char dummy;
491556Srgrimes	SM_FILE_T fake;
501556Srgrimes
511556Srgrimes	/* While snprintf(3) specifies size_t stdio uses an int internally */
521556Srgrimes	if (n > INT_MAX)
531556Srgrimes		n = INT_MAX;
5446684Skris
551556Srgrimes	/* Stdio internals do not deal correctly with zero length buffer */
561556Srgrimes	if (n == 0)
571556Srgrimes	{
581556Srgrimes		str = &dummy;
591556Srgrimes		n = 1;
601556Srgrimes	}
611556Srgrimes	fake.sm_magic = SmFileMagic;
621556Srgrimes	fake.f_timeout = SM_TIME_FOREVER;
631556Srgrimes	fake.f_timeoutstate = SM_TIME_BLOCK;
641556Srgrimes	fake.f_file = -1;
651556Srgrimes	fake.f_flags = SMWR | SMSTR;
661556Srgrimes	fake.f_bf.smb_base = fake.f_p = (unsigned char *)str;
671556Srgrimes	fake.f_bf.smb_size = fake.f_w = n - 1;
681556Srgrimes	fake.f_close = NULL;
691556Srgrimes	fake.f_open = NULL;
701556Srgrimes	fake.f_read = NULL;
711556Srgrimes	fake.f_write = NULL;
721556Srgrimes	fake.f_seek = NULL;
731556Srgrimes	fake.f_setinfo = fake.f_getinfo = NULL;
741556Srgrimes	fake.f_type = "sm_vsnprintf:fake";
751556Srgrimes	ret = sm_io_vfprintf(&fake, SM_TIME_FOREVER, fmt, ap);
761556Srgrimes	*fake.f_p = 0;
771556Srgrimes	return ret;
781556Srgrimes}
791556Srgrimes