182 lines
4.0 KiB
C
182 lines
4.0 KiB
C
/*
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* Revision 12: http://theos.com/~deraadt/snprintf.c
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*
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* Copyright (c) 1997 Theo de Raadt
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "config.h"
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#if !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF)
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <signal.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#if __STDC__
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#include <stdarg.h>
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#include <stdlib.h>
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#else
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#include <varargs.h>
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#endif
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#include <setjmp.h>
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#ifndef roundup
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#define roundup(x, y) ((((x)+((y)-1))/(y))*(y))
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#endif
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static int pgsize;
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static char *curobj;
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static int caught;
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static sigjmp_buf bail;
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#define EXTRABYTES 2 /* XXX: why 2? you don't want to know */
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#ifndef HAVE_GETPAGESIZE
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int
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getpagesize()
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{
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#ifdef EXEC_PAGESIZE
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return EXEC_PAGESIZE;
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#else /* !EXEC_PAGESIZE */
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# ifdef NBPG
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# ifndef CLSIZE
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# define CLSIZE 1
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# endif /* No CLSIZE */
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return NBPG * CLSIZE;
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# else /* !NBPG */
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return NBPC;
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# endif /* NBPG */
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#endif /* EXEC_PAGESIZE */
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}
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#endif /* HAVE_GETPAGESIZE */
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static char *
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msetup(str, n)
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char *str;
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size_t n;
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{
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char *e;
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if (n == 0)
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return NULL;
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if (pgsize == 0)
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pgsize = getpagesize();
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curobj = (char *)malloc(n + EXTRABYTES + pgsize * 2);
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if (curobj == NULL)
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return NULL;
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e = curobj + n + EXTRABYTES;
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e = (char *)roundup((unsigned long)e, pgsize);
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if (mprotect(e, pgsize, PROT_NONE) == -1) {
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free(curobj);
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curobj = NULL;
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return NULL;
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}
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e = e - n - EXTRABYTES;
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*e = '\0';
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return (e);
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}
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static void
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mcatch()
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{
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siglongjmp(bail, 1);
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}
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static void
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mcleanup(str, n, p)
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char *str;
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size_t n;
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char *p;
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{
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strncpy(str, p, n-1);
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str[n-1] = '\0';
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if (mprotect((caddr_t)(p + n + EXTRABYTES), pgsize,
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PROT_READ|PROT_WRITE|PROT_EXEC) == -1)
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mprotect((caddr_t)(p + n + EXTRABYTES), pgsize,
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PROT_READ|PROT_WRITE);
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free(curobj);
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}
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#if !defined(HAVE_VSNPRINTF)
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int
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vsnprintf(str, n, fmt, ap)
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char *str;
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size_t n;
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char *fmt;
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char *ap;
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{
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struct sigaction osa, nsa;
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char *p;
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int ret = n + 1; /* if we bail, indicated we overflowed */
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memset(&nsa, 0, sizeof nsa);
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nsa.sa_handler = mcatch;
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sigemptyset(&nsa.sa_mask);
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p = msetup(str, n);
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if (p == NULL) {
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*str = '\0';
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return 0;
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}
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if (sigsetjmp(bail, 1) == 0) {
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if (sigaction(SIGSEGV, &nsa, &osa) == -1) {
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mcleanup(str, n, p);
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return (0);
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}
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ret = vsprintf(p, fmt, ap);
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}
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mcleanup(str, n, p);
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(void) sigaction(SIGSEGV, &osa, NULL);
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return (ret);
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}
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#endif /* !defined(HAVE_VSNPRINTF) */
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#if !defined(HAVE_SNPRINTF)
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int
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#if __STDC__
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snprintf(char *str, size_t n, char const *fmt, ...)
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#else
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snprintf(str, n, fmt, va_alist)
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char *str;
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size_t n;
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char *fmt;
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va_dcl
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#endif
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{
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va_list ap;
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#if __STDC__
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va_start(ap, fmt);
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#else
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va_start(ap);
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#endif
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return (vsnprintf(str, n, fmt, ap));
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va_end(ap);
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}
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#endif /* !defined(HAVE_SNPRINTF) */
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#endif /* !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF) */
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