/* Copyright (C) 2001-2012 Artifex Software, Inc.
   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied,
   modified or distributed except as expressly authorized under the terms
   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  7 Mt. Lassen Drive - Suite A-134, San Rafael,
   CA  94903, U.S.A., +1(415)492-9861, for further information.
*/

/*
 * Revision 12: http://theos.com/~deraadt/snprintf.c
 *
 * Copyright (c) 1997 Theo de Raadt
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef __VMS
#include <param.h>
#else
#include <sys/param.h>
#endif
#include <sys/types.h>
#include <sys/mman.h>
#include <signal.h>
#include <stdio.h>
#if __STDC__
#include <stdarg.h>
#include <stdlib.h>
#else
#include <varargs.h>
#endif
#include <setjmp.h>
#include <unistd.h>
#include <string.h>

#ifndef roundup
#define roundup(x, y) ((((x)+((y)-1))/(y))*(y))
#endif

#ifdef __sgi
#define size_t ssize_t
#endif

static int pgsize;
static char *curobj;
static int caught;
static sigjmp_buf bail;

#define EXTRABYTES	2	/* XXX: why 2? you don't want to know */

static char *
msetup(str, n)
	char *str;
	size_t n;
{
	char *e;

	if (n == 0)
		return NULL;
	if (pgsize == 0)
		pgsize = getpagesize();
	curobj = (char *)malloc(n + EXTRABYTES + pgsize * 2);
	if (curobj == NULL)
		return NULL;
	e = curobj + n + EXTRABYTES;
	e = (char *)roundup((unsigned long)e, pgsize);
	if (mprotect(e, pgsize, PROT_NONE) == -1) {
		free(curobj);
		curobj = NULL;
		return NULL;
	}
	e = e - n - EXTRABYTES;
	*e = '\0';
	return (e);
}

static void
  mcatch( int a )
{
	siglongjmp(bail, 1);
}

static void
mcleanup(str, n, p)
	char *str;
	size_t n;
	char *p;
{
	strncpy(str, p, n-1);
	str[n-1] = '\0';
	if (mprotect((caddr_t)(p + n + EXTRABYTES), pgsize,
	    PROT_READ|PROT_WRITE|PROT_EXEC) == -1)
		mprotect((caddr_t)(p + n + EXTRABYTES), pgsize,
		    PROT_READ|PROT_WRITE);
	free(curobj);
}

int
#if __STDC__
vsnprintf(char *str, size_t n, char const *fmt, va_list ap)
#else
vsnprintf(str, n, fmt, ap)
	char *str;
	size_t n;
	char *fmt;
	char *ap;
#endif
{
	struct sigaction osa, nsa;
	char *p;
	int ret = n + 1;	/* if we bail, indicated we overflowed */

	memset(&nsa, 0, sizeof nsa);
	nsa.sa_handler = mcatch;
	sigemptyset(&nsa.sa_mask);

	p = msetup(str, n);
	if (p == NULL) {
		*str = '\0';
		return 0;
	}
	if (sigsetjmp(bail, 1) == 0) {
		if (sigaction(SIGSEGV, &nsa, &osa) == -1) {
			mcleanup(str, n, p);
			return (0);
		}
		ret = vsprintf(p, fmt, ap);
	}
	mcleanup(str, n, p);
	(void) sigaction(SIGSEGV, &osa, NULL);
	return (ret);
}

int
#if __STDC__
snprintf(char *str, size_t n, char const *fmt, ...)
#else
snprintf(str, n, fmt, va_alist)
	char *str;
	size_t n;
	char *fmt;
	va_dcl
#endif
{
	va_list ap;
#if __STDC__
	va_start(ap, fmt);
#else
	va_start(ap);
#endif

	return (vsnprintf(str, n, fmt, ap));
	va_end(ap);
}

