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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996-2004
* Sleepycat Software. All rights reserved.
*
* $Id: snprintf.c,v 11.18 2004/09/22 03:32:43 bostic Exp $
*/
#include "db_config.h"
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h> /* Declare STDERR_FILENO. */
#endif
#include "db_int.h"
#if !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF)
static void sprintf_overflow __P((void));
static int sprintf_retcharpnt __P((void));
#endif
/*
* snprintf --
* Bounded version of sprintf.
*
* PUBLIC: #ifndef HAVE_SNPRINTF
* PUBLIC: int snprintf __P((char *, size_t, const char *, ...));
* PUBLIC: #endif
*/
#ifndef HAVE_SNPRINTF
int
#ifdef STDC_HEADERS
snprintf(char *str, size_t n, const char *fmt, ...)
#else
snprintf(str, n, fmt, va_alist)
char *str;
size_t n;
const char *fmt;
va_dcl
#endif
{
static int ret_charpnt = -1;
va_list ap;
size_t len;
if (ret_charpnt == -1)
ret_charpnt = sprintf_retcharpnt();
#ifdef STDC_HEADERS
va_start(ap, fmt);
#else
va_start(ap);
#endif
len = (size_t)vsprintf(str, fmt, ap);
if (ret_charpnt)
len = strlen(str);
va_end(ap);
if (len >= n) {
sprintf_overflow();
/* NOTREACHED */
}
return ((int)len);
}
#endif
/*
* vsnprintf --
* Bounded version of vsprintf.
*
* PUBLIC: #ifndef HAVE_VSNPRINTF
* PUBLIC: int vsnprintf __P((char *, size_t, const char *, va_list));
* PUBLIC: #endif
*/
#ifndef HAVE_VSNPRINTF
int
vsnprintf(str, n, fmt, ap)
char *str;
size_t n;
const char *fmt;
va_list ap;
{
static int ret_charpnt = -1;
size_t len;
if (ret_charpnt == -1)
ret_charpnt = sprintf_retcharpnt();
len = (size_t)vsprintf(str, fmt, ap);
if (ret_charpnt)
len = strlen(str);
if (len >= n) {
sprintf_overflow();
/* NOTREACHED */
}
return ((int)len);
}
#endif
#if !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF)
static void
sprintf_overflow()
{
/*
* !!!
* We're potentially manipulating strings handed us by the application,
* and on systems without a real snprintf() the sprintf() calls could
* have overflowed the buffer. We can't do anything about it now, but
* we don't want to return control to the application, we might have
* overwritten the stack with a Trojan horse. We're not trying to do
* anything recoverable here because systems without snprintf support
* are pretty rare anymore.
*/
#define OVERFLOW_ERROR "internal buffer overflow, process ended\n"
#ifndef STDERR_FILENO
#define STDERR_FILENO 2
#endif
(void)write(STDERR_FILENO, OVERFLOW_ERROR, sizeof(OVERFLOW_ERROR) - 1);
/* Be polite. */
exit(1);
/* But firm. */
abort();
/* NOTREACHED */
}
static int
sprintf_retcharpnt()
{
int ret_charpnt;
char buf[10];
/*
* Some old versions of sprintf return a pointer to the first argument
* instead of a character count. Assume the return value of snprintf,
* vsprintf, etc. will be the same as sprintf, and check the easy one.
*
* We do this test at run-time because it's not a test we can do in a
* cross-compilation environment.
*/
ret_charpnt =
(int)sprintf(buf, "123") != 3 ||
(int)sprintf(buf, "123456789") != 9 ||
(int)sprintf(buf, "1234") != 4;
return (ret_charpnt);
}
#endif
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