lib/libc/stdio/gettemp.c

   1 /*      $NetBSD: gettemp.c,v 1.14 2008/10/20 10:28:38 apb Exp $ */
   2
   3 /*
   4  * Copyright (c) 1987, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #if HAVE_NBTOOL_CONFIG_H
  33 #include "nbtool_config.h"
  34 #endif
  35
  36 #if !HAVE_NBTOOL_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP
  37
  38 #include <sys/cdefs.h>
  39 #if defined(LIBC_SCCS) && !defined(lint)
  40 #if 0
  41 static char sccsid[] = "@(#)mktemp.c    8.1 (Berkeley) 6/4/93";
  42 #else
  43 __RCSID("$NetBSD: gettemp.c,v 1.14 2008/10/20 10:28:38 apb Exp $");
  44 #endif
  45 #endif /* LIBC_SCCS and not lint */
  46
  47 #include <sys/types.h>
  48 #include <sys/stat.h>
  49
  50 #include <assert.h>
  51 #include <ctype.h>
  52 #include <errno.h>
  53 #include <fcntl.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <unistd.h>
  57
  58 #if HAVE_NBTOOL_CONFIG_H
  59 #define GETTEMP         __nbcompat_gettemp
  60 #else
  61 #include "reentrant.h"
  62 #include "local.h"
  63 #define GETTEMP         __gettemp
  64 #endif
  65
  66 int
  67 GETTEMP(path, doopen, domkdir)
  68         char *path;
  69         int *doopen;
  70         int domkdir;
  71 {
  72         char *start, *trv;
  73         struct stat sbuf;
  74         u_int pid;
  75
  76         /* To guarantee multiple calls generate unique names even if
  77            the file is not created. 676 different possibilities with 7
  78            or more X's, 26 with 6 or less. */
  79         static char xtra[2] = "aa";
  80         int xcnt = 0;
  81
  82         _DIAGASSERT(path != NULL);
  83         /* doopen may be NULL */
  84
  85         pid = getpid();
  86
  87         /* Move to end of path and count trailing X's. */
  88         for (trv = path; *trv; ++trv)
  89                 if (*trv == 'X')
  90                         xcnt++;
  91                 else
  92                         xcnt = 0;
  93
  94         /* Use at least one from xtra.  Use 2 if more than 6 X's. */
  95         if (*(trv - 1) == 'X')
  96                 *--trv = xtra[0];
  97         if (xcnt > 6 && *(trv - 1) == 'X')
  98                 *--trv = xtra[1];
  99
 100         /* Set remaining X's to pid digits with 0's to the left. */
 101         while (*--trv == 'X') {
 102                 *trv = (pid % 10) + '0';
 103                 pid /= 10;
 104         }
 105
 106         /* update xtra for next call. */
 107         if (xtra[0] != 'z')
 108                 xtra[0]++;
 109         else {
 110                 xtra[0] = 'a';
 111                 if (xtra[1] != 'z')
 112                         xtra[1]++;
 113                 else
 114                         xtra[1] = 'a';
 115         }
 116
 117         /*
 118          * check the target directory; if you have six X's and it
 119          * doesn't exist this runs for a *very* long time.
 120          */
 121         for (start = trv + 1;; --trv) {
 122                 if (trv <= path)
 123                         break;
 124                 if (*trv == '/') {
 125                         *trv = '\0';
 126                         if (stat(path, &sbuf))
 127                                 return (0);
 128                         if (!S_ISDIR(sbuf.st_mode)) {
 129                                 errno = ENOTDIR;
 130                                 return (0);
 131                         }
 132                         *trv = '/';
 133                         break;
 134                 }
 135         }
 136
 137         for (;;) {
 138                 if (doopen) {
 139                         if ((*doopen =
 140                             open(path, O_CREAT | O_EXCL | O_RDWR, 0600)) >= 0)
 141                                 return (1);
 142                         if (errno != EEXIST)
 143                                 return (0);
 144                 } else if (domkdir) {
 145                         if (mkdir(path, 0700) >= 0)
 146                                 return (1);
 147                         if (errno != EEXIST)
 148                                 return (0);
 149                 } else if (lstat(path, &sbuf))
 150                         return (errno == ENOENT ? 1 : 0);
 151
 152                 /* tricky little algorithm for backward compatibility */
 153                 for (trv = start;;) {
 154                         if (!*trv)
 155                                 return (0);
 156                         if (*trv == 'z')
 157                                 *trv++ = 'a';
 158                         else {
 159                                 if (isdigit((unsigned char)*trv))
 160                                         *trv = 'a';
 161                                 else
 162                                         ++*trv;
 163                                 break;
 164                         }
 165                 }
 166         }
 167         /*NOTREACHED*/
 168 }
 169
 170 #endif /* !HAVE_NBTOOL_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP */