1/* Copyright (C) 1999, 2001-2002, 2006, 2009-2014 Free Software Foundation,
2   Inc.
3   This file is part of the GNU C Library.
4
5   This program is free software: you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by
7   the Free Software Foundation; either version 3 of the License, or
8   (at your option) any later version.
9
10   This program is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   GNU General Public License for more details.
14
15   You should have received a copy of the GNU General Public License
16   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
17
18/* Extracted from sysdeps/posix/tempname.c.  */
19
20#include <config.h>
21
22/* Specification.  */
23#include "tmpdir.h"
24
25#include <stdbool.h>
26#include <stdlib.h>
27#include <string.h>
28
29#include <errno.h>
30#ifndef __set_errno
31# define __set_errno(Val) errno = (Val)
32#endif
33
34#include <stdio.h>
35#ifndef P_tmpdir
36# ifdef _P_tmpdir /* native Windows */
37#  define P_tmpdir _P_tmpdir
38# else
39#  define P_tmpdir "/tmp"
40# endif
41#endif
42
43#include <sys/stat.h>
44
45#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
46# define WIN32_LEAN_AND_MEAN  /* avoid including junk */
47# include <windows.h>
48#endif
49
50#include "pathmax.h"
51
52#if _LIBC
53# define struct_stat64 struct stat64
54#else
55# define struct_stat64 struct stat
56# define __libc_secure_getenv secure_getenv
57# define __xstat64(version, path, buf) stat (path, buf)
58#endif
59
60/* Pathname support.
61   ISSLASH(C)           tests whether C is a directory separator character.
62 */
63#if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__
64  /* Native Windows, Cygwin, OS/2, DOS */
65# define ISSLASH(C) ((C) == '/' || (C) == '\\')
66#else
67  /* Unix */
68# define ISSLASH(C) ((C) == '/')
69#endif
70
71
72/* Return nonzero if DIR is an existent directory.  */
73static bool
74direxists (const char *dir)
75{
76  struct_stat64 buf;
77  return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode);
78}
79
80/* Path search algorithm, for tmpnam, tmpfile, etc.  If DIR is
81   non-null and exists, uses it; otherwise uses the first of $TMPDIR,
82   P_tmpdir, /tmp that exists.  Copies into TMPL a template suitable
83   for use with mk[s]temp.  Will fail (-1) if DIR is non-null and
84   doesn't exist, none of the searched dirs exists, or there's not
85   enough space in TMPL. */
86int
87path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
88             bool try_tmpdir)
89{
90  const char *d;
91  size_t dlen, plen;
92  bool add_slash;
93
94  if (!pfx || !pfx[0])
95    {
96      pfx = "file";
97      plen = 4;
98    }
99  else
100    {
101      plen = strlen (pfx);
102      if (plen > 5)
103        plen = 5;
104    }
105
106  if (try_tmpdir)
107    {
108      d = __libc_secure_getenv ("TMPDIR");
109      if (d != NULL && direxists (d))
110        dir = d;
111      else if (dir != NULL && direxists (dir))
112        /* nothing */ ;
113      else
114        dir = NULL;
115    }
116  if (dir == NULL)
117    {
118#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
119      char dirbuf[PATH_MAX];
120      DWORD retval;
121
122      /* Find Windows temporary file directory.
123         We try this before P_tmpdir because Windows defines P_tmpdir to "\\"
124         and will therefore try to put all temporary files in the root
125         directory (unless $TMPDIR is set).  */
126      retval = GetTempPath (PATH_MAX, dirbuf);
127      if (retval > 0 && retval < PATH_MAX && direxists (dirbuf))
128        dir = dirbuf;
129      else
130#endif
131      if (direxists (P_tmpdir))
132        dir = P_tmpdir;
133      else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
134        dir = "/tmp";
135      else
136        {
137          __set_errno (ENOENT);
138          return -1;
139        }
140    }
141
142  dlen = strlen (dir);
143#ifdef __VMS
144  add_slash = 0;
145#else
146  add_slash = dlen != 0 && !ISSLASH (dir[dlen - 1]);
147#endif
148
149  /* check we have room for "${dir}/${pfx}XXXXXX\0" */
150  if (tmpl_len < dlen + add_slash + plen + 6 + 1)
151    {
152      __set_errno (EINVAL);
153      return -1;
154    }
155
156  memcpy (tmpl, dir, dlen);
157  sprintf (tmpl + dlen, &"/%.*sXXXXXX"[!add_slash], (int) plen, pfx);
158  return 0;
159}
160