ref: 7ea64ae21664e0752401a53dfda9b601691275a5
dir: /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. */ #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); }