1/* Utility to pick a temporary filename prefix.
2   Copyright (C) 1996, 1997, 1998, 2001, 2009 Free Software Foundation, Inc.
3
4This file is part of the libiberty library.
5Libiberty is free software; you can redistribute it and/or
6modify it under the terms of the GNU Library General Public
7License as published by the Free Software Foundation; either
8version 2 of the License, or (at your option) any later version.
9
10Libiberty is distributed in the hope that it will be useful,
11but WITHOUT ANY WARRANTY; without even the implied warranty of
12MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13Library General Public License for more details.
14
15You should have received a copy of the GNU Library General Public
16License along with libiberty; see the file COPYING.LIB.  If not,
17write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
18Boston, MA 02110-1301, USA.  */
19
20#ifdef HAVE_CONFIG_H
21#include "config.h"
22#endif
23
24#include <stdio.h>	/* May get P_tmpdir.  */
25#include <sys/types.h>
26#include <errno.h>
27#ifdef HAVE_UNISTD_H
28#include <unistd.h>
29#endif
30#ifdef HAVE_STDLIB_H
31#include <stdlib.h>
32#endif
33#ifdef HAVE_STRING_H
34#include <string.h>
35#endif
36#ifdef HAVE_SYS_FILE_H
37#include <sys/file.h>   /* May get R_OK, etc. on some systems.  */
38#endif
39#if defined(_WIN32) && !defined(__CYGWIN__)
40#include <windows.h>
41#endif
42
43#ifndef R_OK
44#define R_OK 4
45#define W_OK 2
46#define X_OK 1
47#endif
48
49#include "libiberty.h"
50extern int mkstemps (char *, int);
51
52/* '/' works just fine on MS-DOS based systems.  */
53#ifndef DIR_SEPARATOR
54#define DIR_SEPARATOR '/'
55#endif
56
57/* Name of temporary file.
58   mktemp requires 6 trailing X's.  */
59#define TEMP_FILE "ccXXXXXX"
60#define TEMP_FILE_LEN (sizeof(TEMP_FILE) - 1)
61
62#if !defined(_WIN32) || defined(__CYGWIN__)
63
64/* Subroutine of choose_tmpdir.
65   If BASE is non-NULL, return it.
66   Otherwise it checks if DIR is a usable directory.
67   If success, DIR is returned.
68   Otherwise NULL is returned.  */
69
70static inline const char *try_dir (const char *, const char *);
71
72static inline const char *
73try_dir (const char *dir, const char *base)
74{
75  if (base != 0)
76    return base;
77  if (dir != 0
78      && access (dir, R_OK | W_OK | X_OK) == 0)
79    return dir;
80  return 0;
81}
82
83static const char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };
84static const char usrtmp[] =
85{ DIR_SEPARATOR, 'u', 's', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
86static const char vartmp[] =
87{ DIR_SEPARATOR, 'v', 'a', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
88
89#endif
90
91static char *memoized_tmpdir;
92
93/*
94
95@deftypefn Replacement char* choose_tmpdir ()
96
97Returns a pointer to a directory path suitable for creating temporary
98files in.
99
100@end deftypefn
101
102*/
103
104char *
105choose_tmpdir (void)
106{
107  if (!memoized_tmpdir)
108    {
109#if !defined(_WIN32) || defined(__CYGWIN__)
110      const char *base = 0;
111      char *tmpdir;
112      unsigned int len;
113
114#ifdef VMS
115      /* Try VMS standard temp logical.  */
116      base = try_dir ("/sys$scratch", base);
117#else
118      base = try_dir (getenv ("TMPDIR"), base);
119      base = try_dir (getenv ("TMP"), base);
120      base = try_dir (getenv ("TEMP"), base);
121#endif
122
123#ifdef P_tmpdir
124      base = try_dir (P_tmpdir, base);
125#endif
126
127      /* Try /var/tmp, /usr/tmp, then /tmp.  */
128      base = try_dir (vartmp, base);
129      base = try_dir (usrtmp, base);
130      base = try_dir (tmp, base);
131
132      /* If all else fails, use the current directory!  */
133      if (base == 0)
134	base = ".";
135      /* Append DIR_SEPARATOR to the directory we've chosen
136	 and return it.  */
137      len = strlen (base);
138      tmpdir = XNEWVEC (char, len + 2);
139      strcpy (tmpdir, base);
140      tmpdir[len] = DIR_SEPARATOR;
141      tmpdir[len+1] = '\0';
142      memoized_tmpdir = tmpdir;
143#else /* defined(_WIN32) && !defined(__CYGWIN__) */
144      DWORD len;
145
146      /* Figure out how much space we need.  */
147      len = GetTempPath(0, NULL);
148      if (len)
149	{
150	  memoized_tmpdir = XNEWVEC (char, len);
151	  if (!GetTempPath(len, memoized_tmpdir))
152	    {
153	      XDELETEVEC (memoized_tmpdir);
154	      memoized_tmpdir = NULL;
155	    }
156	}
157      if (!memoized_tmpdir)
158	/* If all else fails, use the current directory.  */
159	memoized_tmpdir = xstrdup (".\\");
160#endif /* defined(_WIN32) && !defined(__CYGWIN__) */
161    }
162
163  return memoized_tmpdir;
164}
165
166/*
167
168@deftypefn Replacement char* make_temp_file (const char *@var{suffix})
169
170Return a temporary file name (as a string) or @code{NULL} if unable to
171create one.  @var{suffix} is a suffix to append to the file name.  The
172string is @code{malloc}ed, and the temporary file has been created.
173
174@end deftypefn
175
176*/
177
178char *
179make_temp_file (const char *suffix)
180{
181  const char *base = choose_tmpdir ();
182  char *temp_filename;
183  int base_len, suffix_len;
184  int fd;
185
186  if (suffix == 0)
187    suffix = "";
188
189  base_len = strlen (base);
190  suffix_len = strlen (suffix);
191
192  temp_filename = XNEWVEC (char, base_len
193			   + TEMP_FILE_LEN
194			   + suffix_len + 1);
195  strcpy (temp_filename, base);
196  strcpy (temp_filename + base_len, TEMP_FILE);
197  strcpy (temp_filename + base_len + TEMP_FILE_LEN, suffix);
198
199  fd = mkstemps (temp_filename, suffix_len);
200  /* Mkstemps failed.  It may be EPERM, ENOSPC etc.  */
201  if (fd == -1)
202    {
203      fprintf (stderr, "Cannot create temporary file in %s: %s\n",
204	       base, strerror (errno));
205      abort ();
206    }
207  /* We abort on failed close out of sheer paranoia.  */
208  if (close (fd))
209    abort ();
210  return temp_filename;
211}
212