/* * 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 voidmcatch(int a){    siglongjmp(bail, 1);} static voidmcleanup(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)#elsevsnprintf(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, ...)#elsesnprintf(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);}