StdLib/LibC/Stdio/gettemp.c

   1 /** @file
   2   Internal function to generate temporary file name for tmpnam.
   3
   4   Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials are licensed and made available
   6   under the terms and conditions of the BSD License that accompanies this
   7   distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php.
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13   Copyright (c) 1987, 1993
  14    The Regents of the University of California.  All rights reserved.
  15
  16   Redistribution and use in source and binary forms, with or without
  17   modification, are permitted provided that the following conditions
  18   are met:
  19     1. Redistributions of source code must retain the above copyright
  20        notice, this list of conditions and the following disclaimer.
  21     2. Redistributions in binary form must reproduce the above copyright
  22        notice, this list of conditions and the following disclaimer in the
  23        documentation and/or other materials provided with the distribution.
  24     3. Neither the name of the University nor the names of its contributors
  25        may be used to endorse or promote products derived from this software
  26        without specific prior written permission.
  27
  28   THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29   ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31   ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34   OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37   OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38   SUCH DAMAGE.
  39
  40   mktemp.c  8.1 (Berkeley) 6/4/93
  41   NetBSD: gettemp.c,v 1.13 2003/12/05 00:57:36 uebayasi Exp
  42 **/
  43 #include  <LibConfig.h>
  44
  45 #if HAVE_NBTOOL_CONFIG_H
  46 #include "nbtool_config.h"
  47 #endif
  48
  49 #if !defined(HAVE_NBTOOL_CONFIG_H) || !defined(HAVE_MKSTEMP) || !defined(HAVE_MKDTEMP)
  50
  51 #include <sys/EfiCdefs.h>
  52
  53 #include <sys/types.h>
  54 #include <sys/stat.h>
  55
  56 #include <assert.h>
  57 #include <ctype.h>
  58 #include <errno.h>
  59 #include <fcntl.h>
  60 #include <stdio.h>
  61 #include <stdlib.h>
  62 #include  <unistd.h>
  63
  64 #if HAVE_NBTOOL_CONFIG_H
  65 #define GETTEMP   gettemp
  66 #else
  67 #include "reentrant.h"
  68 #include "local.h"
  69 #define GETTEMP   __gettemp
  70 #endif
  71
  72 int
  73 GETTEMP(
  74   char *path,
  75   int *doopen,
  76   int domkdir
  77   )
  78 {
  79   char *start, *trv;
  80   struct stat sbuf;
  81
  82   /* To guarantee multiple calls generate unique names even if
  83      the file is not created. 676 different possibilities with 7
  84      or more X's, 26 with 6 or less. */
  85   static char xtra[] = "aa";
  86   int xcnt = 0;
  87
  88   _DIAGASSERT(path != NULL);
  89   /* doopen may be NULL */
  90
  91   /* Move to end of path and count trailing X's. */
  92   for (trv = path; *trv; ++trv) {
  93     if (*trv == 'X') {
  94       xcnt++;
  95     }
  96     else {
  97       xcnt = 0;
  98     }
  99   }
 100
 101   /* Use at least one from xtra.  Use 2 if more than 6 X's. */
 102   if (*(trv - 1) == 'X')
 103     *--trv = xtra[0];
 104   if (xcnt > 6 && *(trv - 1) == 'X')
 105     *--trv = xtra[1];
 106
 107   /* Set remaining X's to 0's. */
 108   while (*--trv == 'X') {
 109     *trv = '0';
 110   }
 111
 112   /* update xtra for next call. */
 113   if (xtra[0] != 'z')
 114     xtra[0]++;
 115   else {
 116     xtra[0] = 'a';
 117     if (xtra[1] != 'z')
 118       xtra[1]++;
 119     else
 120       xtra[1] = 'a';
 121   }
 122
 123   /*
 124    * check the target directory; if you have six X's and it
 125    * doesn't exist this runs for a *very* long time.
 126    */
 127   for (start = trv + 1;; --trv) {
 128     if (trv <= path)
 129       break;
 130     if (*trv == '/') {
 131       *trv = '\0';
 132       if (stat(path, &sbuf))
 133         return (0);
 134       if (!S_ISDIR(sbuf.st_mode)) {
 135         errno = ENOTDIR;
 136         return (0);
 137       }
 138       *trv = '/';
 139       break;
 140     }
 141   }
 142
 143   for (;;) {
 144     if (doopen) {
 145       if ((*doopen =
 146           open(path, O_CREAT | O_EXCL | O_RDWR, 0600)) >= 0)
 147         return (1);
 148       if (errno != EEXIST)
 149         return (0);
 150     } else if (domkdir) {
 151       if (mkdir(path, 0700) >= 0)
 152         return (1);
 153       if (errno != EEXIST)
 154         return (0);
 155     } else if (lstat(path, &sbuf))
 156       return (errno == ENOENT ? 1 : 0);
 157
 158     /* tricky little algorithm for backward compatibility */
 159     for (trv = start;;) {
 160       if (!*trv)
 161         return (0);
 162       if (*trv == 'z') {
 163         *trv++ = 'a';
 164       }
 165       else {
 166         if (isdigit((unsigned char)*trv))
 167           *trv = 'a';
 168         else
 169           ++*trv;
 170         break;
 171       }
 172     }
 173   }
 174   /*NOTREACHED*/
 175 }
 176
 177 #endif /* !HAVE_NBTOOL_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP */