swish-e/src/vsnprintf.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 <sys/param.h>
#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>

#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()
{
        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);
}


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 <sys/param.h>
28	#include <sys/types.h>
29	#include <sys/mman.h>
30	#include <signal.h>
31	#include <stdio.h>
32	#if __STDC__
33	#include <stdarg.h>
34	#include <stdlib.h>
35	#else
36	#include <varargs.h>
37	#endif
38	#include <setjmp.h>
39
40	#ifndef roundup
41	#define roundup(x, y) ((((x)+((y)-1))/(y))*(y))
42	#endif
43
44	#ifdef __sgi
45	#define size_t ssize_t
46	#endif
47
48	static int pgsize;
49	static char *curobj;
50	static int caught;
51	static sigjmp_buf bail;
52
53	#define EXTRABYTES 2 /* XXX: why 2? you don't want to know */
54
55	static char *
56	msetup(str, n)
57	char *str;
58	size_t n;
59	{
60	char *e;
61
62	if (n == 0)
63	return NULL;
64	if (pgsize == 0)
65	pgsize = getpagesize();
66	curobj = (char )malloc(n + EXTRABYTES + pgsize 2);
67	if (curobj == NULL)
68	return NULL;
69	e = curobj + n + EXTRABYTES;
70	e = (char *)roundup((unsigned long)e, pgsize);
71	if (mprotect(e, pgsize, PROT_NONE) == -1) {
72	free(curobj);
73	curobj = NULL;
74	return NULL;
75	}
76	e = e - n - EXTRABYTES;
77	*e = '\0';
78	return (e);
79	}
80
81	static void
82	mcatch()
83	{
84	siglongjmp(bail, 1);
85	}
86
87	static void
88	mcleanup(str, n, p)
89	char *str;
90	size_t n;
91	char *p;
92	{
93	strncpy(str, p, n-1);
94	str[n-1] = '\0';
95	if (mprotect((caddr_t)(p + n + EXTRABYTES), pgsize,
96	PROT_READ\|PROT_WRITE\|PROT_EXEC) == -1)
97	mprotect((caddr_t)(p + n + EXTRABYTES), pgsize,
98	PROT_READ\|PROT_WRITE);
99	free(curobj);
100	}
101
102	int
103	#if __STDC__
104	vsnprintf(char str, size_t n, char const fmt, va_list ap)
105	#else
106	vsnprintf(str, n, fmt, ap)
107	char *str;
108	size_t n;
109	char *fmt;
110	char *ap;
111	#endif
112	{
113	struct sigaction osa, nsa;
114	char *p;
115	int ret = n + 1; /* if we bail, indicated we overflowed */
116
117	memset(&nsa, 0, sizeof nsa);
118	nsa.sa_handler = mcatch;
119	sigemptyset(&nsa.sa_mask);
120
121	p = msetup(str, n);
122	if (p == NULL) {
123	*str = '\0';
124	return 0;
125	}
126	if (sigsetjmp(bail, 1) == 0) {
127	if (sigaction(SIGSEGV, &nsa, &osa) == -1) {
128	mcleanup(str, n, p);
129	return (0);
130	}
131	ret = vsprintf(p, fmt, ap);
132	}
133	mcleanup(str, n, p);
134	(void) sigaction(SIGSEGV, &osa, NULL);
135	return (ret);
136	}
137
138	int
139	#if __STDC__
140	snprintf(char str, size_t n, char const fmt, ...)
141	#else
142	snprintf(str, n, fmt, va_alist)
143	char *str;
144	size_t n;
145	char *fmt;
146	va_dcl
147	#endif
148	{
149	va_list ap;
150	#if __STDC__
151	va_start(ap, fmt);
152	#else
153	va_start(ap);
154	#endif
155
156	return (vsnprintf(str, n, fmt, ap));
157	va_end(ap);
158	}
159
160
161