1 /* -*- buffer-read-only: t -*- vi: set ro: */
2 /* DO NOT EDIT! GENERATED AUTOMATICALLY! */
3 /* tempname.c - generate the name of a temporary file.
5 Copyright (C) 1991-2003, 2005-2007, 2009-2014 Free Software Foundation, Inc.
7 This program is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20 /* Extracted from glibc sysdeps/posix/tempname.c. See also tmpdir.c. */
24 # include "tempname.h"
27 #include <sys/types.h>
32 # define __set_errno(Val) errno = (Val)
37 # define P_tmpdir "/tmp"
40 # define TMP_MAX 238328
45 # define __GT_NOCREATE 2
47 #if !_LIBC && (GT_FILE != __GT_FILE || GT_DIR != __GT_DIR \
48 || GT_NOCREATE != __GT_NOCREATE)
49 # error report this to bug-gnulib@gnu.org
64 # define struct_stat64 struct stat64
66 # define struct_stat64 struct stat
67 # define __gen_tempname gen_tempname
68 # define __getpid getpid
69 # define __gettimeofday gettimeofday
70 # define __mkdir mkdir
72 # define __lxstat64(version, file, buf) lstat (file, buf)
73 # define __secure_getenv secure_getenv
77 # include <hp-timing.h>
79 # define RANDOM_BITS(Var) \
80 if (__builtin_expect (value == UINT64_C (0), 0)) \
82 /* If this is the first time this function is used initialize \
83 the variable we accumulate the value in to some somewhat \
84 random value. If we'd not do this programs at startup time \
85 might have a reduced set of possible names, at least on slow \
88 __gettimeofday (&tv, NULL); \
89 value = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec; \
95 /* Use the widest available unsigned type if uint64_t is not
96 available. The algorithm below extracts a number less than 62**6
97 (approximately 2**35.725) from uint64_t, so ancient hosts where
98 uintmax_t is only 32 bits lose about 3.725 bits of randomness,
99 which is better than not having mkstemp at all. */
100 #if !defined UINT64_MAX && !defined uint64_t
101 # define uint64_t uintmax_t
105 /* Return nonzero if DIR is an existent directory. */
107 direxists (const char *dir)
110 return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode);
113 /* Path search algorithm, for tmpnam, tmpfile, etc. If DIR is
114 non-null and exists, uses it; otherwise uses the first of $TMPDIR,
115 P_tmpdir, /tmp that exists. Copies into TMPL a template suitable
116 for use with mk[s]temp. Will fail (-1) if DIR is non-null and
117 doesn't exist, none of the searched dirs exists, or there's not
118 enough space in TMPL. */
120 __path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
140 d = __secure_getenv ("TMPDIR");
141 if (d != NULL && direxists (d))
143 else if (dir != NULL && direxists (dir))
150 if (direxists (P_tmpdir))
152 else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
156 __set_errno (ENOENT);
162 while (dlen > 1 && dir[dlen - 1] == '/')
163 dlen--; /* remove trailing slashes */
165 /* check we have room for "${dir}/${pfx}XXXXXX\0" */
166 if (tmpl_len < dlen + 1 + plen + 6 + 1)
168 __set_errno (EINVAL);
172 sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx);
177 /* These are the characters used in temporary file names. */
178 static const char letters[] =
179 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
181 /* Generate a temporary file name based on TMPL. TMPL must match the
182 rules for mk[s]temp (i.e. end in "XXXXXX", possibly with a suffix).
183 The name constructed does not exist at the time of the call to
184 __gen_tempname. TMPL is overwritten with the result.
187 __GT_NOCREATE: simply verify that the name does not exist
188 at the time of the call.
189 __GT_FILE: create the file using open(O_CREAT|O_EXCL)
190 and return a read-write fd. The file is mode 0600.
191 __GT_DIR: create a directory, which will be mode 0700.
193 We use a clever algorithm to get hard-to-predict names. */
195 __gen_tempname (char *tmpl, int suffixlen, int flags, int kind)
199 static uint64_t value;
200 uint64_t random_time_bits;
203 int save_errno = errno;
206 /* A lower bound on the number of temporary files to attempt to
207 generate. The maximum total number of temporary file names that
208 can exist for a given template is 62**6. It should never be
209 necessary to try all of these combinations. Instead if a reasonable
210 number of names is tried (we define reasonable as 62**3) fail to
211 give the system administrator the chance to remove the problems. */
212 #define ATTEMPTS_MIN (62 * 62 * 62)
214 /* The number of times to attempt to generate a temporary file. To
215 conform to POSIX, this must be no smaller than TMP_MAX. */
216 #if ATTEMPTS_MIN < TMP_MAX
217 unsigned int attempts = TMP_MAX;
219 unsigned int attempts = ATTEMPTS_MIN;
223 if (len < 6 + suffixlen || memcmp (&tmpl[len - 6 - suffixlen], "XXXXXX", 6))
225 __set_errno (EINVAL);
229 /* This is where the Xs start. */
230 XXXXXX = &tmpl[len - 6 - suffixlen];
232 /* Get some more or less random data. */
234 RANDOM_BITS (random_time_bits);
238 __gettimeofday (&tv, NULL);
239 random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;
242 value += random_time_bits ^ __getpid ();
244 for (count = 0; count < attempts; value += 7777, ++count)
248 /* Fill in the random bits. */
249 XXXXXX[0] = letters[v % 62];
251 XXXXXX[1] = letters[v % 62];
253 XXXXXX[2] = letters[v % 62];
255 XXXXXX[3] = letters[v % 62];
257 XXXXXX[4] = letters[v % 62];
259 XXXXXX[5] = letters[v % 62];
266 | O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
270 fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR);
274 /* This case is backward from the other three. __gen_tempname
275 succeeds if __xstat fails because the name does not exist.
276 Note the continue to bypass the common logic at the bottom
278 if (__lxstat64 (_STAT_VER, tmpl, &st) < 0)
282 __set_errno (save_errno);
292 assert (! "invalid KIND in __gen_tempname");
298 __set_errno (save_errno);
301 else if (errno != EEXIST)
305 /* We got out of the loop because we ran out of combinations to try. */
306 __set_errno (EEXIST);