[openssh.git] / bsd-snprintf.c

/*
 * 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.
 */

#include "config.h"

#if defined(BROKEN_SNPRINTF) || !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF)

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

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

#ifndef HAVE_GETPAGESIZE
int
getpagesize()
{
#ifdef EXEC_PAGESIZE
  return EXEC_PAGESIZE;
#else /* !EXEC_PAGESIZE */
# ifdef NBPG
#  ifndef CLSIZE
#   define CLSIZE	1
#  endif /* No CLSIZE */
  return NBPG * CLSIZE;
# else /* !NBPG */
  return NBPC;
# endif /* NBPG */
#endif /* EXEC_PAGESIZE */
}
#endif /* HAVE_GETPAGESIZE */

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()
{
	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);
}

#if !defined(HAVE_VSNPRINTF) || defined(BROKEN_SNPRINTF)
int
vsnprintf(str, n, fmt, ap)
	char *str;
	size_t n;
	char *fmt;
	va_list ap;
{
	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);
}
#endif /* !defined(HAVE_VSNPRINTF) || defined(BROKEN_SNPRINTF) */

#if !defined(HAVE_SNPRINTF) || defined(BROKEN_SNPRINTF)
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);
}
#endif /* !defined(HAVE_SNPRINTF) || defined(BROKEN_SNPRINTF) */

#endif /* defined(BROKEN_SNPRINTF) || !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF) */
Commit	Line	Data
dad3b556	1	/*
	2	* Revision 12: http://theos.com/~deraadt/snprintf.c
	3	*
	4	* Copyright (c) 1997 Theo de Raadt
	5	*
	6	* Redistribution and use in source and binary forms, with or without
	7	* modification, are permitted provided that the following conditions
	8	* are met:
	9	* 1. Redistributions of source code must retain the above copyright
	10	* notice, this list of conditions and the following disclaimer.
	11	* 2. Redistributions in binary form must reproduce the above copyright
	12	* notice, this list of conditions and the following disclaimer in the
	13	* documentation and/or other materials provided with the distribution.
	14	*
	15	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	16	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	17	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	18	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	19	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	20	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	21	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	22	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	23	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	24	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	25	*/
	26
	27	#include "config.h"
	28
2647ae26	29	#if defined(BROKEN_SNPRINTF) \|\| !defined(HAVE_SNPRINTF) \|\| !defined(HAVE_VSNPRINTF)
dad3b556	30
	31	#include <sys/param.h>
	32	#include <sys/types.h>
	33	#include <sys/mman.h>
	34	#include <signal.h>
	35	#include <stdio.h>
	36	#include <unistd.h>
	37	#include <string.h>
	38	#if __STDC__
	39	#include <stdarg.h>
	40	#include <stdlib.h>
	41	#else
	42	#include <varargs.h>
	43	#endif
	44	#include <setjmp.h>
	45
	46	#ifndef roundup
e844f761	47	#define roundup(x, y) ((((x)+((y)-1))/(y))*(y))
dad3b556	48	#endif
	49
	50	static int pgsize;
	51	static char *curobj;
	52	static int caught;
	53	static sigjmp_buf bail;
	54
	55	#define EXTRABYTES 2 /* XXX: why 2? you don't want to know */
	56
b6019d68	57	#ifndef HAVE_GETPAGESIZE
	58	int
	59	getpagesize()
	60	{
	61	#ifdef EXEC_PAGESIZE
	62	return EXEC_PAGESIZE;
	63	#else /* !EXEC_PAGESIZE */
	64	# ifdef NBPG
	65	# ifndef CLSIZE
	66	# define CLSIZE 1
	67	# endif /* No CLSIZE */
	68	return NBPG * CLSIZE;
	69	# else /* !NBPG */
	70	return NBPC;
	71	# endif /* NBPG */
	72	#endif /* EXEC_PAGESIZE */
	73	}
	74	#endif /* HAVE_GETPAGESIZE */
	75
dad3b556	76	static char *
	77	msetup(str, n)
	78	char *str;
	79	size_t n;
	80	{
	81	char *e;
	82
	83	if (n == 0)
	84	return NULL;
	85	if (pgsize == 0)
	86	pgsize = getpagesize();
	87	curobj = (char )malloc(n + EXTRABYTES + pgsize 2);
	88	if (curobj == NULL)
	89	return NULL;
	90	e = curobj + n + EXTRABYTES;
	91	e = (char *)roundup((unsigned long)e, pgsize);
	92	if (mprotect(e, pgsize, PROT_NONE) == -1) {
	93	free(curobj);
	94	curobj = NULL;
	95	return NULL;
	96	}
	97	e = e - n - EXTRABYTES;
	98	*e = '\0';
	99	return (e);
	100	}
	101
	102	static void
	103	mcatch()
	104	{
	105	siglongjmp(bail, 1);
	106	}
	107
	108	static void
	109	mcleanup(str, n, p)
	110	char *str;
	111	size_t n;
	112	char *p;
	113	{
	114	strncpy(str, p, n-1);
	115	str[n-1] = '\0';
	116	if (mprotect((caddr_t)(p + n + EXTRABYTES), pgsize,
	117	PROT_READ\|PROT_WRITE\|PROT_EXEC) == -1)
	118	mprotect((caddr_t)(p + n + EXTRABYTES), pgsize,
	119	PROT_READ\|PROT_WRITE);
	120	free(curobj);
	121	}
	122
2647ae26	123	#if !defined(HAVE_VSNPRINTF) \|\| defined(BROKEN_SNPRINTF)
dad3b556	124	int
	125	vsnprintf(str, n, fmt, ap)
	126	char *str;
	127	size_t n;
	128	char *fmt;
4d33e531	129	va_list ap;
dad3b556	130	{
	131	struct sigaction osa, nsa;
	132	char *p;
	133	int ret = n + 1; /* if we bail, indicated we overflowed */
	134
	135	memset(&nsa, 0, sizeof nsa);
	136	nsa.sa_handler = mcatch;
	137	sigemptyset(&nsa.sa_mask);
	138
	139	p = msetup(str, n);
	140	if (p == NULL) {
	141	*str = '\0';
	142	return 0;
	143	}
	144	if (sigsetjmp(bail, 1) == 0) {
	145	if (sigaction(SIGSEGV, &nsa, &osa) == -1) {
	146	mcleanup(str, n, p);
	147	return (0);
	148	}
	149	ret = vsprintf(p, fmt, ap);
	150	}
	151	mcleanup(str, n, p);
	152	(void) sigaction(SIGSEGV, &osa, NULL);
	153	return (ret);
	154	}
2647ae26	155	#endif /* !defined(HAVE_VSNPRINTF) \|\| defined(BROKEN_SNPRINTF) */
dad3b556	156
2647ae26	157	#if !defined(HAVE_SNPRINTF) \|\| defined(BROKEN_SNPRINTF)
847e8865	158	int
	159	#if __STDC__
	160	snprintf(char str, size_t n, char const fmt, ...)
	161	#else
	162	snprintf(str, n, fmt, va_alist)
	163	char *str;
	164	size_t n;
	165	char *fmt;
	166	va_dcl
	167	#endif
	168	{
	169	va_list ap;
	170	#if __STDC__
	171	va_start(ap, fmt);
	172	#else
	173	va_start(ap);
	174	#endif
	175
	176	return (vsnprintf(str, n, fmt, ap));
	177	va_end(ap);
	178	}
2647ae26	179	#endif /* !defined(HAVE_SNPRINTF) \|\| defined(BROKEN_SNPRINTF) */
847e8865	180
2647ae26	181	#endif /* defined(BROKEN_SNPRINTF) \|\| !defined(HAVE_SNPRINTF) \|\| !defined(HAVE_VSNPRINTF) */