1/* Copyright (C) 1999, 2001-2002, 2006 Free Software Foundation, Inc.
2   This file is part of the GNU C Library.
3
4   This program is free software; you can redistribute it and/or modify
5   it under the terms of the GNU General Public License as published by
6   the Free Software Foundation; either version 2, or (at your option)
7   any later version.
8
9   This program 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
12   GNU General Public License for more details.
13
14   You should have received a copy of the GNU General Public License
15   along with this program; if not, write to the Free Software Foundation,
16   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
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# define P_tmpdir "/tmp"
37#endif
38
39#include <sys/stat.h>
40#if !defined S_ISDIR && defined S_IFDIR
41# define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
42#endif
43#if !S_IRUSR && S_IREAD
44# define S_IRUSR S_IREAD
45#endif
46#if !S_IRUSR
47# define S_IRUSR 00400
48#endif
49#if !S_IWUSR && S_IWRITE
50# define S_IWUSR S_IWRITE
51#endif
52#if !S_IWUSR
53# define S_IWUSR 00200
54#endif
55#if !S_IXUSR && S_IEXEC
56# define S_IXUSR S_IEXEC
57#endif
58#if !S_IXUSR
59# define S_IXUSR 00100
60#endif
61
62#if _LIBC
63# define struct_stat64 struct stat64
64#else
65# define struct_stat64 struct stat
66# define __xstat64(version, path, buf) stat (path, buf)
67#endif
68
69#if ! (HAVE___SECURE_GETENV || _LIBC)
70# define __secure_getenv getenv
71#endif
72
73/* Pathname support.
74   ISSLASH(C)           tests whether C is a directory separator character.
75 */
76#if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__
77  /* Win32, Cygwin, OS/2, DOS */
78# define ISSLASH(C) ((C) == '/' || (C) == '\\')
79#else
80  /* Unix */
81# define ISSLASH(C) ((C) == '/')
82#endif
83
84
85/* Return nonzero if DIR is an existent directory.  */
86static bool
87direxists (const char *dir)
88{
89  struct_stat64 buf;
90  return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode);
91}
92
93/* Path search algorithm, for tmpnam, tmpfile, etc.  If DIR is
94   non-null and exists, uses it; otherwise uses the first of $TMPDIR,
95   P_tmpdir, /tmp that exists.  Copies into TMPL a template suitable
96   for use with mk[s]temp.  Will fail (-1) if DIR is non-null and
97   doesn't exist, none of the searched dirs exists, or there's not
98   enough space in TMPL. */
99int
100path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
101	     bool try_tmpdir)
102{
103  const char *d;
104  size_t dlen, plen;
105
106  if (!pfx || !pfx[0])
107    {
108      pfx = "file";
109      plen = 4;
110    }
111  else
112    {
113      plen = strlen (pfx);
114      if (plen > 5)
115	plen = 5;
116    }
117
118  if (try_tmpdir)
119    {
120      d = __secure_getenv ("TMPDIR");
121      if (d != NULL && direxists (d))
122	dir = d;
123      else if (dir != NULL && direxists (dir))
124	/* nothing */ ;
125      else
126	dir = NULL;
127    }
128  if (dir == NULL)
129    {
130      if (direxists (P_tmpdir))
131	dir = P_tmpdir;
132      else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
133	dir = "/tmp";
134      else
135	{
136	  __set_errno (ENOENT);
137	  return -1;
138	}
139    }
140
141  dlen = strlen (dir);
142  while (dlen >= 1 && ISSLASH (dir[dlen - 1]))
143    dlen--;			/* remove trailing slashes */
144
145  /* check we have room for "${dir}/${pfx}XXXXXX\0" */
146  if (tmpl_len < dlen + 1 + plen + 6 + 1)
147    {
148      __set_errno (EINVAL);
149      return -1;
150    }
151
152  sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx);
153  return 0;
154}
155