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/* $NetBSD: mkstemp.c,v 1.4 2007/08/07 02:06:59 lukem Exp $ */
/* from NetBSD: gettemp.c,v 1.13 2003/12/05 00:57:36 uebayasi Exp */
/*
* 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.
*/
#include "tnftp.h"
int
mkstemp(char *path)
{
char *start, *trv;
struct stat sbuf;
unsigned int pid;
int fd;
/* To guarantee multiple calls generate unique names even if
the file is not created. 676 different possibilities with 7
or more X's, 26 with 6 or less. */
static char xtra[2] = "aa";
int xcnt = 0;
pid = getpid();
/* Move to end of path and count trailing X's. */
for (trv = path; *trv; ++trv)
if (*trv == 'X')
xcnt++;
else
xcnt = 0;
/* Use at least one from xtra. Use 2 if more than 6 X's. */
if (*(trv - 1) == 'X')
*--trv = xtra[0];
if (xcnt > 6 && *(trv - 1) == 'X')
*--trv = xtra[1];
/* Set remaining X's to pid digits with 0's to the left. */
while (*--trv == 'X') {
*trv = (pid % 10) + '0';
pid /= 10;
}
/* update xtra for next call. */
if (xtra[0] != 'z')
xtra[0]++;
else {
xtra[0] = 'a';
if (xtra[1] != 'z')
xtra[1]++;
else
xtra[1] = 'a';
}
/*
* check the target directory; if you have six X's and it
* doesn't exist this runs for a *very* long time.
*/
for (start = trv + 1;; --trv) {
if (trv <= path)
break;
if (*trv == '/') {
*trv = '\0';
if (stat(path, &sbuf))
return (-1);
if (!S_ISDIR(sbuf.st_mode)) {
errno = ENOTDIR;
return (-1);
}
*trv = '/';
break;
}
}
for (;;) {
if ((fd = open(path, O_CREAT | O_EXCL | O_RDWR, 0600)) >= 0)
return (fd);
if (errno != EEXIST)
return (-1);
/* tricky little algorithm for backward compatibility */
for (trv = start;;) {
if (!*trv)
return (-1);
if (*trv == 'z')
*trv++ = 'a';
else {
if (isdigit((unsigned char)*trv))
*trv = 'a';
else
++*trv;
break;
}
}
}
/*NOTREACHED*/
}
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