text: /*
   * Copyright (c) 1987, 1993
   *	The Regents of the University of California.  All rights reserved.
   *
   * 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.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
   *
   * @(#)mktemp.c	8.1 (Berkeley) 6/4/93
   * $FreeBSD: src/lib/libc/stdio/mktemp.c,v 1.31 2008/07/28 21:18:59 jhb Exp $
   * $DragonFly: src/lib/libc/stdio/mktemp.c,v 1.7 2005/11/20 11:07:30 swildner Exp $
   */
  
  #include "namespace.h"
  #include <sys/param.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  #include <errno.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <ctype.h>
  #include <unistd.h>
  #include "un-namespace.h"
  
  char *_mktemp(char *);
  
  static int _gettemp(char *, int *, int, int, int);
  
  static const unsigned char padchar[] =
  "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  
  int
  mkstemps(char *path, int slen)
  {
  	int fd;
  
  	return (_gettemp(path, &fd, 0, slen, 0) ? fd : -1);
  }
  
  int
  mkostemps(char *path, int slen, int oflags)
  {
  	int fd;
  
  	return (_gettemp(path, &fd, 0, slen, oflags) ? fd : -1);
  }
  
  int
  mkstemp(char *path)
  {
  	int fd;
  
  	return (_gettemp(path, &fd, 0, 0, 0) ? fd : -1);
  }
  
  int
  mkostemp(char *path, int oflags)
  {
  	int fd;
  
  	return (_gettemp(path, &fd, 0, 0, oflags) ? fd : -1);
  }
  
  char *
  mkdtemp(char *path)
  {
  	return (_gettemp(path, NULL, 1, 0, 0) ? path : NULL);
  }
  
  char *
  _mktemp(char *path)
  {
  	return (_gettemp(path, NULL, 0, 0, 0) ? path : NULL);
  }
  
  __warn_references(mktemp,
      "warning: mktemp() possibly used unsafely; consider using mkstemp()");
  
  char *
  mktemp(char *path)
  {
  	return (_mktemp(path));
  }
  
  static int
  _gettemp(char *path, int *doopen, int domkdir, int slen, int oflags)
  {
  	char *start, *trv, *suffp, *carryp;
  	char *pad;
  	struct stat sbuf;
  	int rval;
  	uint32_t rand;
  	char carrybuf[MAXPATHLEN];
  
  	if ((oflags & ~(O_APPEND | O_DIRECT | O_SHLOCK |
  		        O_EXLOCK | O_SYNC | O_CLOEXEC)) != 0) {
  		errno = EINVAL;
  		return (0);
  	}
  	if ((doopen != NULL && domkdir) || slen < 0) {
  		errno = EINVAL;
  		return (0);
  	}
  
  	for (trv = path; *trv != '\0'; ++trv)
  		;
  	trv -= slen;
  	suffp = trv;
  	--trv;
  	if (trv < path || NULL != strchr(suffp, '/')) {
  		errno = EINVAL;
  		return (0);
  	}
  
  	/* Fill space with random characters */
  	while (trv >= path && *trv == 'X') {
  		rand = arc4random_uniform(sizeof(padchar) - 1);
  		*trv-- = padchar[rand];
  	}
  	start = trv + 1;
  
  	/* save first combination of random characters */
  	memcpy(carrybuf, start, suffp - start);
  
  	/*
  	 * check the target directory.
  	 */
  	if (doopen != NULL || domkdir) {
  		for (; trv > path; --trv) {
  			if (*trv == '/') {
  				*trv = '\0';
  				rval = stat(path, &sbuf);
  				*trv = '/';
  				if (rval != 0)
  					return (0);
  				if (!S_ISDIR(sbuf.st_mode)) {
  					errno = ENOTDIR;
  					return (0);
  				}
  				break;
  			}
  		}
  	}
  
  	for (;;) {
  		if (doopen) {
  			if ((*doopen =
  			    _open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
  				return (1);
  			if (errno != EEXIST)
  				return (0);
  		} else if (domkdir) {
  			if (mkdir(path, 0700) == 0)
  				return (1);
  			if (errno != EEXIST)
  				return (0);
  		} else if (lstat(path, &sbuf))
  			return (errno == ENOENT);
  
  		/* If we have a collision, cycle through the space of filenames */
  		for (trv = start, carryp = carrybuf;;) {
  			/* have we tried all possible permutations? */
  			if (trv == suffp)
  				return (0); /* yes - exit with EEXIST */
  			pad = strchr(padchar, *trv);
  			if (pad == NULL) {
  				/* this should never happen */
  				errno = EIO;
  				return (0);
  			}
  			/* increment character */
  			*trv = (*++pad == '\0') ? padchar[0] : *pad;
  			/* carry to next position? */
  			if (*trv == *carryp) {
  				/* increment position and loop */
  				++trv;
  				++carryp;
  			} else {
  				/* try with new name */
  				break;
  			}
  		}
  	}
  	/*NOTREACHED*/
  }
  