1 /* Copyright (C) 1991-1999, 2000, 2001 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
23 #include <sys/types.h>
28 # define __set_errno(Val) errno = (Val)
33 # define P_tmpdir "/tmp"
36 # define TMP_MAX 238328
40 # define __GT_BIGFILE 1
42 # define __GT_NOCREATE 3
45 #if STDC_HEADERS || _LIBC
52 #if HAVE_FCNTL_H || _LIBC
56 #if HAVE_SYS_TIME_H || _LIBC
57 # include <sys/time.h>
60 #if HAVE_STDINT_H || _LIBC
64 #if HAVE_UNISTD_H || _LIBC
69 #if STAT_MACROS_BROKEN
72 #if !defined S_ISDIR && defined S_IFDIR
73 # define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
75 #if !S_IRUSR && S_IREAD
76 # define S_IRUSR S_IREAD
79 # define S_IRUSR 00400
81 #if !S_IWUSR && S_IWRITE
82 # define S_IWUSR S_IWRITE
85 # define S_IWUSR 00200
87 #if !S_IXUSR && S_IEXEC
88 # define S_IXUSR S_IEXEC
91 # define S_IXUSR 00100
95 # define struct_stat64 struct stat64
97 # define struct_stat64 struct stat
98 # define __getpid getpid
99 # define __gettimeofday gettimeofday
100 # define __mkdir mkdir
102 # define __open64 open
103 # define __lxstat64(version, path, buf) lstat (path, buf)
104 # define __xstat64(version, path, buf) stat (path, buf)
107 #if ! (HAVE___SECURE_GETENV || _LIBC)
108 # define __secure_getenv getenv
110 # ifndef HAVE_DECL_GETENV
111 "this configure-time declaration test was not run"
113 # if !HAVE_DECL_GETENV
119 # include <hp-timing.h>
121 # define RANDOM_BITS(Var) \
122 if (__builtin_expect (value == UINT64_C (0), 0)) \
124 /* If this is the first time this function is used initialize \
125 the variable we accumulate the value in to some somewhat \
126 random value. If we'd not do this programs at startup time \
127 might have a reduced set of possible names, at least on slow \
130 __gettimeofday (&tv, NULL); \
131 value = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec; \
137 /* Use the widest available unsigned type if uint64_t is not
138 available. The algorithm below extracts a number less than 62**6
139 (approximately 2**35.725) from uint64_t, so ancient hosts where
140 uintmax_t is only 32 bits lose about 3.725 bits of randomness,
141 which is better than not having mkstemp at all. */
142 #if !defined UINT64_MAX && !defined uint64_t
143 # define uint64_t uintmax_t
146 /* Return nonzero if DIR is an existent directory. */
148 direxists (const char *dir)
151 return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode);
154 /* Path search algorithm, for tmpnam, tmpfile, etc. If DIR is
155 non-null and exists, uses it; otherwise uses the first of $TMPDIR,
156 P_tmpdir, /tmp that exists. Copies into TMPL a template suitable
157 for use with mk[s]temp. Will fail (-1) if DIR is non-null and
158 doesn't exist, none of the searched dirs exists, or there's not
159 enough space in TMPL. */
161 __path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
181 d = __secure_getenv ("TMPDIR");
182 if (d != NULL && direxists (d))
184 else if (dir != NULL && direxists (dir))
191 if (direxists (P_tmpdir))
193 else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
197 __set_errno (ENOENT);
203 while (dlen > 1 && dir[dlen - 1] == '/')
204 dlen--; /* remove trailing slashes */
206 /* check we have room for "${dir}/${pfx}XXXXXX\0" */
207 if (tmpl_len < dlen + 1 + plen + 6 + 1)
209 __set_errno (EINVAL);
213 sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx);
217 /* These are the characters used in temporary filenames. */
218 static const char letters[] =
219 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
221 /* Generate a temporary file name based on TMPL. TMPL must match the
222 rules for mk[s]temp (i.e. end in "XXXXXX"). The name constructed
223 does not exist at the time of the call to __gen_tempname. TMPL is
224 overwritten with the result.
227 __GT_NOCREATE: simply verify that the name does not exist
228 at the time of the call.
229 __GT_FILE: create the file using open(O_CREAT|O_EXCL)
230 and return a read-write fd. The file is mode 0600.
231 __GT_BIGFILE: same as __GT_FILE but use open64().
232 __GT_DIR: create a directory, which will be mode 0700.
234 We use a clever algorithm to get hard-to-predict names. */
236 __gen_tempname (char *tmpl, int kind)
240 static uint64_t value;
241 uint64_t random_time_bits;
244 int save_errno = errno;
247 /* A lower bound on the number of temporary files to attempt to
248 generate. The maximum total number of temporary file names that
249 can exist for a given template is 62**6. It should never be
250 necessary to try all these combinations. Instead if a reasonable
251 number of names is tried (we define reasonable as 62**3) fail to
252 give the system administrator the chance to remove the problems. */
253 unsigned int attempts_min = 62 * 62 * 62;
255 /* The number of times to attempt to generate a temporary file. To
256 conform to POSIX, this must be no smaller than TMP_MAX. */
257 unsigned int attempts = attempts_min < TMP_MAX ? TMP_MAX : attempts_min;
260 if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX"))
262 __set_errno (EINVAL);
266 /* This is where the Xs start. */
267 XXXXXX = &tmpl[len - 6];
269 /* Get some more or less random data. */
271 RANDOM_BITS (random_time_bits);
273 # if HAVE_GETTIMEOFDAY || _LIBC
276 __gettimeofday (&tv, NULL);
277 random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;
280 random_time_bits = time (NULL);
283 value += random_time_bits ^ __getpid ();
285 for (count = 0; count < attempts; value += 7777, ++count)
289 /* Fill in the random bits. */
290 XXXXXX[0] = letters[v % 62];
292 XXXXXX[1] = letters[v % 62];
294 XXXXXX[2] = letters[v % 62];
296 XXXXXX[3] = letters[v % 62];
298 XXXXXX[4] = letters[v % 62];
300 XXXXXX[5] = letters[v % 62];
305 fd = __open (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
309 fd = __open64 (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
313 fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR);
317 /* This case is backward from the other three. __gen_tempname
318 succeeds if __xstat fails because the name does not exist.
319 Note the continue to bypass the common logic at the bottom
321 if (__lxstat64 (_STAT_VER, tmpl, &st) < 0)
325 __set_errno (save_errno);
335 assert (! "invalid KIND in __gen_tempname");
340 __set_errno (save_errno);
343 else if (errno != EEXIST)
347 /* We got out of the loop because we ran out of combinations to try. */
348 __set_errno (EEXIST);