1/* Utility to pick a temporary filename prefix.
2   Copyright (C) 1996-2022 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#if HAVE_SYS_STAT_H
43#include <sys/stat.h>
44#endif
45
46
47#ifndef R_OK
48#define R_OK 4
49#define W_OK 2
50#define X_OK 1
51#endif
52
53#include "libiberty.h"
54extern int mkstemps (char *, int);
55
56/* '/' works just fine on MS-DOS based systems.  */
57#ifndef DIR_SEPARATOR
58#define DIR_SEPARATOR '/'
59#endif
60
61/* Name of temporary file.
62   mktemp requires 6 trailing X's.  */
63#define TEMP_FILE "XXXXXX"
64#define TEMP_FILE_LEN (sizeof(TEMP_FILE) - 1)
65
66#if !defined(_WIN32) || defined(__CYGWIN__)
67
68/* Subroutine of choose_tmpdir.
69   If BASE is non-NULL, return it.
70   Otherwise it checks if DIR is a usable directory.
71   If success, DIR is returned.
72   Otherwise NULL is returned.  */
73
74static inline const char *try_dir (const char *, const char *);
75
76static inline const char *
77try_dir (const char *dir, const char *base)
78{
79  if (base != 0)
80    return base;
81  if (dir != 0
82      && access (dir, R_OK | W_OK | X_OK) == 0)
83    {
84      /* Check to make sure dir is actually a directory. */
85#ifdef S_ISDIR
86      struct stat s;
87      if (stat (dir, &s))
88	return NULL;
89      if (!S_ISDIR (s.st_mode))
90	return NULL;
91#endif
92      return dir;
93    }
94  return 0;
95}
96
97static const char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };
98static const char usrtmp[] =
99{ DIR_SEPARATOR, 'u', 's', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
100static const char vartmp[] =
101{ DIR_SEPARATOR, 'v', 'a', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
102
103#endif
104
105static char *memoized_tmpdir;
106
107/*
108
109@deftypefn Replacement const char* choose_tmpdir ()
110
111Returns a pointer to a directory path suitable for creating temporary
112files in.
113
114@end deftypefn
115
116*/
117
118const char *
119choose_tmpdir (void)
120{
121  if (!memoized_tmpdir)
122    {
123#if !defined(_WIN32) || defined(__CYGWIN__)
124      const char *base = 0;
125      char *tmpdir;
126      unsigned int len;
127
128#ifdef VMS
129      /* Try VMS standard temp logical.  */
130      base = try_dir ("/sys$scratch", base);
131#else
132      base = try_dir (getenv ("TMPDIR"), base);
133      base = try_dir (getenv ("TMP"), base);
134      base = try_dir (getenv ("TEMP"), base);
135#endif
136
137#ifdef P_tmpdir
138      /* We really want a directory name here as if concatenated with say \dir
139	 we do not end up with a double \\ which defines an UNC path.  */
140      if (strcmp (P_tmpdir, "\\") == 0)
141	base = try_dir ("\\.", base);
142      else
143	base = try_dir (P_tmpdir, base);
144#endif
145
146      /* Try /tmp, /var/tmp, then /usr/tmp.  */
147      base = try_dir (tmp, base);
148      base = try_dir (vartmp, base);
149      base = try_dir (usrtmp, base);
150
151      /* If all else fails, use the current directory!  */
152      if (base == 0)
153	base = ".";
154      /* Append DIR_SEPARATOR to the directory we've chosen
155	 and return it.  */
156      len = strlen (base);
157      tmpdir = XNEWVEC (char, len + 2);
158      strcpy (tmpdir, base);
159      tmpdir[len] = DIR_SEPARATOR;
160      tmpdir[len+1] = '\0';
161      memoized_tmpdir = tmpdir;
162#else /* defined(_WIN32) && !defined(__CYGWIN__) */
163      DWORD len;
164
165      /* Figure out how much space we need.  */
166      len = GetTempPath(0, NULL);
167      if (len)
168	{
169	  memoized_tmpdir = XNEWVEC (char, len);
170	  if (!GetTempPath(len, memoized_tmpdir))
171	    {
172	      XDELETEVEC (memoized_tmpdir);
173	      memoized_tmpdir = NULL;
174	    }
175	}
176      if (!memoized_tmpdir)
177	/* If all else fails, use the current directory.  */
178	memoized_tmpdir = xstrdup (".\\");
179#endif /* defined(_WIN32) && !defined(__CYGWIN__) */
180    }
181
182  return memoized_tmpdir;
183}
184
185/*
186
187@deftypefn Replacement char* make_temp_file (const char *@var{suffix})
188
189Return a temporary file name (as a string) or @code{NULL} if unable to
190create one.  @var{suffix} is a suffix to append to the file name.  The
191string is @code{malloc}ed, and the temporary file has been created.
192
193@end deftypefn
194
195*/
196
197char *
198make_temp_file_with_prefix (const char *prefix, const char *suffix)
199{
200  const char *base = choose_tmpdir ();
201  char *temp_filename;
202  int base_len, suffix_len, prefix_len;
203  int fd;
204
205  if (prefix == 0)
206    prefix = "cc";
207
208  if (suffix == 0)
209    suffix = "";
210
211  base_len = strlen (base);
212  prefix_len = strlen (prefix);
213  suffix_len = strlen (suffix);
214
215  temp_filename = XNEWVEC (char, base_len
216			   + TEMP_FILE_LEN
217			   + suffix_len
218			   + prefix_len + 1);
219  strcpy (temp_filename, base);
220  strcpy (temp_filename + base_len, prefix);
221  strcpy (temp_filename + base_len + prefix_len, TEMP_FILE);
222  strcpy (temp_filename + base_len + prefix_len + TEMP_FILE_LEN, suffix);
223
224  fd = mkstemps (temp_filename, suffix_len);
225  /* Mkstemps failed.  It may be EPERM, ENOSPC etc.  */
226  if (fd == -1)
227    {
228      fprintf (stderr, "Cannot create temporary file in %s: %s\n",
229	       base, strerror (errno));
230      abort ();
231    }
232  /* We abort on failed close out of sheer paranoia.  */
233  if (close (fd))
234    abort ();
235  return temp_filename;
236}
237
238char *
239make_temp_file (const char *suffix)
240{
241  return make_temp_file_with_prefix (NULL, suffix);
242}
243