1 /* Utility to pick a temporary filename prefix.
2 Copyright (C) 1996-2023 Free Software Foundation, Inc.
3
4 This file is part of the libiberty library.
5 Libiberty is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9
10 Libiberty 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 GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with libiberty; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
18 Boston, 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 #define WIN32_LEAN_AND_MEAN
41 #include <windows.h>
42 #endif
43 #if HAVE_SYS_STAT_H
44 #include <sys/stat.h>
45 #endif
46
47
48 #ifndef R_OK
49 #define R_OK 4
50 #define W_OK 2
51 #define X_OK 1
52 #endif
53
54 #include "libiberty.h"
55 extern int mkstemps (char *, int);
56
57 /* '/' works just fine on MS-DOS based systems. */
58 #ifndef DIR_SEPARATOR
59 #define DIR_SEPARATOR '/'
60 #endif
61
62 /* Name of temporary file.
63 mktemp requires 6 trailing X's. */
64 #define TEMP_FILE "XXXXXX"
65 #define TEMP_FILE_LEN (sizeof(TEMP_FILE) - 1)
66
67 #if !defined(_WIN32) || defined(__CYGWIN__)
68
69 /* Subroutine of choose_tmpdir.
70 If BASE is non-NULL, return it.
71 Otherwise it checks if DIR is a usable directory.
72 If success, DIR is returned.
73 Otherwise NULL is returned. */
74
75 static inline const char *try_dir (const char *, const char *);
76
77 static inline const char *
78 try_dir (const char *dir, const char *base)
79 {
80 if (base != 0)
81 return base;
82 if (dir != 0
83 && access (dir, R_OK | W_OK | X_OK) == 0)
84 {
85 /* Check to make sure dir is actually a directory. */
86 #ifdef S_ISDIR
87 struct stat s;
88 if (stat (dir, &s))
89 return NULL;
90 if (!S_ISDIR (s.st_mode))
91 return NULL;
92 #endif
93 return dir;
94 }
95 return 0;
96 }
97
98 static const char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };
99 static const char vartmp[] =
100 { DIR_SEPARATOR, 'v', 'a', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
101
102 #endif
103
104 static char *memoized_tmpdir;
105
106 /*
107
108 @deftypefn Replacement const char* choose_tmpdir ()
109
110 Returns a pointer to a directory path suitable for creating temporary
111 files in.
112
113 @end deftypefn
114
115 */
116
117 const char *
118 choose_tmpdir (void)
119 {
120 if (!memoized_tmpdir)
121 {
122 #if !defined(_WIN32) || defined(__CYGWIN__)
123 const char *base = 0;
124 char *tmpdir;
125 unsigned int len;
126
127 #ifdef VMS
128 /* Try VMS standard temp logical. */
129 base = try_dir ("/sys$scratch", base);
130 #else
131 base = try_dir (getenv ("TMPDIR"), base);
132 base = try_dir (getenv ("TMP"), base);
133 base = try_dir (getenv ("TEMP"), base);
134 #endif
135
136 #ifdef P_tmpdir
137 /* We really want a directory name here as if concatenated with say \dir
138 we do not end up with a double \\ which defines an UNC path. */
139 if (strcmp (P_tmpdir, "\\") == 0)
140 base = try_dir ("\\.", base);
141 else
142 base = try_dir (P_tmpdir, base);
143 #endif
144
145 /* Try /var/tmp, then /tmp. */
146 base = try_dir (vartmp, base);
147 base = try_dir (tmp, base);
148
149 /* If all else fails, use the current directory! */
150 if (base == 0)
151 base = ".";
152 /* Append DIR_SEPARATOR to the directory we've chosen
153 and return it. */
154 len = strlen (base);
155 tmpdir = XNEWVEC (char, len + 2);
156 strcpy (tmpdir, base);
157 tmpdir[len] = DIR_SEPARATOR;
158 tmpdir[len+1] = '\0';
159 memoized_tmpdir = tmpdir;
160 #else /* defined(_WIN32) && !defined(__CYGWIN__) */
161 DWORD len;
162
163 /* Figure out how much space we need. */
164 len = GetTempPath(0, NULL);
165 if (len)
166 {
167 memoized_tmpdir = XNEWVEC (char, len);
168 if (!GetTempPath(len, memoized_tmpdir))
169 {
170 XDELETEVEC (memoized_tmpdir);
171 memoized_tmpdir = NULL;
172 }
173 }
174 if (!memoized_tmpdir)
175 /* If all else fails, use the current directory. */
176 memoized_tmpdir = xstrdup (".\\");
177 #endif /* defined(_WIN32) && !defined(__CYGWIN__) */
178 }
179
180 return memoized_tmpdir;
181 }
182
183 /*
184
185 @deftypefn Replacement char* make_temp_file (const char *@var{suffix})
186
187 Return a temporary file name (as a string) or @code{NULL} if unable to
188 create one. @var{suffix} is a suffix to append to the file name. The
189 string is @code{malloc}ed, and the temporary file has been created.
190
191 @end deftypefn
192
193 */
194
195 char *
196 make_temp_file_with_prefix (const char *prefix, const char *suffix)
197 {
198 const char *base = choose_tmpdir ();
199 char *temp_filename;
200 int base_len, suffix_len, prefix_len;
201 int fd;
202
203 if (prefix == 0)
204 prefix = "cc";
205
206 if (suffix == 0)
207 suffix = "";
208
209 base_len = strlen (base);
210 prefix_len = strlen (prefix);
211 suffix_len = strlen (suffix);
212
213 temp_filename = XNEWVEC (char, base_len
214 + TEMP_FILE_LEN
215 + suffix_len
216 + prefix_len + 1);
217 strcpy (temp_filename, base);
218 strcpy (temp_filename + base_len, prefix);
219 strcpy (temp_filename + base_len + prefix_len, TEMP_FILE);
220 strcpy (temp_filename + base_len + prefix_len + TEMP_FILE_LEN, suffix);
221
222 fd = mkstemps (temp_filename, suffix_len);
223 /* Mkstemps failed. It may be EPERM, ENOSPC etc. */
224 if (fd == -1)
225 {
226 fprintf (stderr, "Cannot create temporary file in %s: %s\n",
227 base, strerror (errno));
228 abort ();
229 }
230 /* We abort on failed close out of sheer paranoia. */
231 if (close (fd))
232 abort ();
233 return temp_filename;
234 }
235
236 char *
237 make_temp_file (const char *suffix)
238 {
239 return make_temp_file_with_prefix (NULL, suffix);
240 }