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/*
* 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);
}
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