source: rtems-tools/rtemstoolkit/libiberty/mkstemps.c @ 87e0e76

4.104.11
Last change on this file since 87e0e76 was 87e0e76, checked in by Chris Johns <chrisj@…>, on Sep 13, 2014 at 2:09:16 AM

Refactor code into the RTEMS Toolkit.

  • Property mode set to 100644
File size: 3.7 KB
Line 
1/* Copyright (C) 1991, 1992, 1996, 1998, 2004 Free Software Foundation, Inc.
2   This file is derived from mkstemp.c from the GNU C Library.
3
4   The GNU C Library is free software; you can redistribute it and/or
5   modify it under the terms of the GNU Library General Public License as
6   published by the Free Software Foundation; either version 2 of the
7   License, or (at your option) any later version.
8
9   The GNU C Library is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   Library General Public License for more details.
13
14   You should have received a copy of the GNU Library General Public
15   License along with the GNU C Library; see the file COPYING.LIB.  If not,
16   write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
17   Boston, MA 02110-1301, USA.  */
18
19#ifdef HAVE_CONFIG_H
20#include "config.h"
21#endif
22
23#include <sys/types.h>
24#ifdef HAVE_STDLIB_H
25#include <stdlib.h>
26#endif
27#ifdef HAVE_STRING_H
28#include <string.h>
29#endif
30#include <errno.h>
31#include <stdio.h>
32#include <fcntl.h>
33#ifdef HAVE_UNISTD_H
34#include <unistd.h>
35#endif
36#ifdef HAVE_SYS_TIME_H
37#include <sys/time.h>
38#endif
39#include "ansidecl.h"
40
41/* We need to provide a type for gcc_uint64_t.  */
42#ifdef __GNUC__
43__extension__ typedef unsigned long long gcc_uint64_t;
44#else
45typedef unsigned long gcc_uint64_t;
46#endif
47
48#ifndef TMP_MAX
49#define TMP_MAX 16384
50#endif
51
52#ifndef O_BINARY
53# define O_BINARY 0
54#endif
55
56/*
57
58@deftypefn Replacement int mkstemps (char *@var{pattern}, int @var{suffix_len})
59
60Generate a unique temporary file name from @var{pattern}.
61@var{pattern} has the form:
62
63@example
64   @var{path}/ccXXXXXX@var{suffix}
65@end example
66
67@var{suffix_len} tells us how long @var{suffix} is (it can be zero
68length).  The last six characters of @var{pattern} before @var{suffix}
69must be @samp{XXXXXX}; they are replaced with a string that makes the
70filename unique.  Returns a file descriptor open on the file for
71reading and writing.
72
73@end deftypefn
74
75*/
76
77int
78mkstemps (char *pattern, int suffix_len)
79{
80  static const char letters[]
81    = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
82  static gcc_uint64_t value;
83#ifdef HAVE_GETTIMEOFDAY
84  struct timeval tv;
85#endif
86  char *XXXXXX;
87  size_t len;
88  int count;
89
90  len = strlen (pattern);
91
92  if ((int) len < 6 + suffix_len
93      || strncmp (&pattern[len - 6 - suffix_len], "XXXXXX", 6))
94    {
95      return -1;
96    }
97
98  XXXXXX = &pattern[len - 6 - suffix_len];
99
100#ifdef HAVE_GETTIMEOFDAY
101  /* Get some more or less random data.  */
102  gettimeofday (&tv, NULL);
103  value += ((gcc_uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
104#else
105  value += getpid ();
106#endif
107
108  for (count = 0; count < TMP_MAX; ++count)
109    {
110      gcc_uint64_t v = value;
111      int fd;
112
113      /* Fill in the random bits.  */
114      XXXXXX[0] = letters[v % 62];
115      v /= 62;
116      XXXXXX[1] = letters[v % 62];
117      v /= 62;
118      XXXXXX[2] = letters[v % 62];
119      v /= 62;
120      XXXXXX[3] = letters[v % 62];
121      v /= 62;
122      XXXXXX[4] = letters[v % 62];
123      v /= 62;
124      XXXXXX[5] = letters[v % 62];
125
126      fd = open (pattern, O_BINARY|O_RDWR|O_CREAT|O_EXCL, 0600);
127      if (fd >= 0)
128        /* The file does not exist.  */
129        return fd;
130      if (errno != EEXIST
131#ifdef EISDIR
132          && errno != EISDIR
133#endif
134         )
135        /* Fatal error (EPERM, ENOSPC etc).  Doesn't make sense to loop.  */
136        break;
137
138      /* This is a random value.  It is only necessary that the next
139         TMP_MAX values generated by adding 7777 to VALUE are different
140         with (module 2^32).  */
141      value += 7777;
142    }
143
144  /* We return the null string if we can't find a unique file name.  */
145  pattern[0] = '\0';
146  return -1;
147}
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