122 lines
3.3 KiB
C
122 lines
3.3 KiB
C
/* $NetBSD: mkstemp.c,v 1.3 2003/09/06 23:03:03 grant Exp $ */
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/*
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* Copyright (c) 1987, 1993
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* The Regents of the University of California. All rights reserved.
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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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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "nbcompat.h"
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int
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mkstemp(char *path)
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{
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char *start, *trv;
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struct stat sbuf;
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u_int pid;
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int fd;
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/* To guarantee multiple calls generate unique names even if
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the file is not created. 676 different possibilities with 7
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or more X's, 26 with 6 or less. */
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static char xtra[2] = "aa";
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int xcnt = 0;
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pid = getpid();
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/* Move to end of path and count trailing X's. */
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for (trv = path; *trv; ++trv)
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if (*trv == 'X')
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xcnt++;
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else
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xcnt = 0;
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/* Use at least one from xtra. Use 2 if more than 6 X's. */
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if (*(trv-1) == 'X')
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*--trv = xtra[0];
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if (xcnt > 6 && *(trv-1) == 'X')
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*--trv = xtra[1];
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/* Set remaining X's to pid digits with 0's to the left. */
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while (*--trv == 'X') {
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*trv = (pid % 10) + '0';
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pid /= 10;
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}
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/* update xtra for next call. */
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if (xtra[0] != 'z')
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xtra[0]++;
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else {
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xtra[0] = 'a';
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if (xtra[1] != 'z')
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xtra[1]++;
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else
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xtra[1] = 'a';
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}
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/*
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* check the target directory; if you have six X's and it
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* doesn't exist this runs for a *very* long time.
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*/
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for (start = trv + 1;; --trv) {
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if (trv <= path)
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break;
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if (*trv == '/') {
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*trv = '\0';
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if (stat(path, &sbuf))
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return (-1);
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if (!S_ISDIR(sbuf.st_mode)) {
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errno = ENOTDIR;
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return (-1);
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}
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*trv = '/';
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break;
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}
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}
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for (;;) {
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if ((fd = open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
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return (fd);
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if (errno != EEXIST)
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return (-1);
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/* tricky little algorithm for backward compatibility */
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for (trv = start;;) {
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if (!*trv)
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return (-1);
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if (*trv == 'z')
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*trv++ = 'a';
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else {
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if (isdigit((unsigned char)*trv))
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*trv = 'a';
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else
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++*trv;
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break;
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}
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}
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}
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/*NOTREACHED*/
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}
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