1 /* Copyright (C) 1999, 2001-2002, 2006, 2009-2020 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 <https://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 __CYGWIN__
46 # define WIN32_LEAN_AND_MEAN /* avoid including junk */
47 # include <windows.h>
48 #endif
49
50 #include "pathmax.h"
51
52 #if defined _WIN32 && ! defined __CYGWIN__
53 /* Don't assume that UNICODE is not defined. */
54 # undef GetTempPath
55 # define GetTempPath GetTempPathA
56 #endif
57
58 #if _LIBC
59 # define struct_stat64 struct stat64
60 #else
61 # define struct_stat64 struct stat
62 # define __libc_secure_getenv secure_getenv
63 # define __xstat64(version, path, buf) stat (path, buf)
64 #endif
65
66 /* Pathname support.
67 ISSLASH(C) tests whether C is a directory separator character.
68 */
69 #if defined _WIN32 || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__
70 /* Native Windows, Cygwin, OS/2, DOS */
71 # define ISSLASH(C) ((C) == '/' || (C) == '\\')
72 #else
73 /* Unix */
74 # define ISSLASH(C) ((C) == '/')
75 #endif
76
77
78 /* Return nonzero if DIR is an existent directory. */
79 static bool
direxists(const char * dir)80 direxists (const char *dir)
81 {
82 struct_stat64 buf;
83 return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode);
84 }
85
86 /* Path search algorithm, for tmpnam, tmpfile, etc. If DIR is
87 non-null and exists, uses it; otherwise uses the first of $TMPDIR,
88 P_tmpdir, /tmp that exists. Copies into TMPL a template suitable
89 for use with mk[s]temp. Will fail (-1) if DIR is non-null and
90 doesn't exist, none of the searched dirs exists, or there's not
91 enough space in TMPL. */
92 int
path_search(char * tmpl,size_t tmpl_len,const char * dir,const char * pfx,bool try_tmpdir)93 path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
94 bool try_tmpdir)
95 {
96 const char *d;
97 size_t dlen, plen;
98 bool add_slash;
99
100 if (!pfx || !pfx[0])
101 {
102 pfx = "file";
103 plen = 4;
104 }
105 else
106 {
107 plen = strlen (pfx);
108 if (plen > 5)
109 plen = 5;
110 }
111
112 if (try_tmpdir)
113 {
114 d = __libc_secure_getenv ("TMPDIR");
115 if (d != NULL && direxists (d))
116 dir = d;
117 else if (dir != NULL && direxists (dir))
118 /* nothing */ ;
119 else
120 dir = NULL;
121 }
122 if (dir == NULL)
123 {
124 #if defined _WIN32 && ! defined __CYGWIN__
125 char dirbuf[PATH_MAX];
126 DWORD retval;
127
128 /* Find Windows temporary file directory.
129 We try this before P_tmpdir because Windows defines P_tmpdir to "\\"
130 and will therefore try to put all temporary files in the root
131 directory (unless $TMPDIR is set). */
132 retval = GetTempPath (PATH_MAX, dirbuf);
133 if (retval > 0 && retval < PATH_MAX && direxists (dirbuf))
134 dir = dirbuf;
135 else
136 #endif
137 if (direxists (P_tmpdir))
138 dir = P_tmpdir;
139 else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
140 dir = "/tmp";
141 else
142 {
143 __set_errno (ENOENT);
144 return -1;
145 }
146 }
147
148 dlen = strlen (dir);
149 #ifdef __VMS
150 add_slash = 0;
151 #else
152 add_slash = dlen != 0 && !ISSLASH (dir[dlen - 1]);
153 #endif
154
155 /* check we have room for "${dir}/${pfx}XXXXXX\0" */
156 if (tmpl_len < dlen + add_slash + plen + 6 + 1)
157 {
158 __set_errno (EINVAL);
159 return -1;
160 }
161
162 memcpy (tmpl, dir, dlen);
163 sprintf (tmpl + dlen, &"/%.*sXXXXXX"[!add_slash], (int) plen, pfx);
164 return 0;
165 }
166