1 /* Copyright (C) 1991-1999, 2000, 2001 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
9 This program 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
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software Foundation,
16 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
22 #include <sys/types.h>
27 # define __set_errno(Val) errno = (Val)
32 # define P_tmpdir "/tmp"
35 # define TMP_MAX 238328
39 # define __GT_BIGFILE 1
41 # define __GT_NOCREATE 3
44 #if STDC_HEADERS || _LIBC
51 #if HAVE_FCNTL_H || _LIBC
55 #if HAVE_SYS_TIME_H || _LIBC
56 # include <sys/time.h>
59 #if HAVE_STDINT_H || _LIBC
63 #if HAVE_UNISTD_H || _LIBC
68 #if STAT_MACROS_BROKEN
71 #if !defined S_ISDIR && defined S_IFDIR
72 # define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
74 #if !S_IRUSR && S_IREAD
75 # define S_IRUSR S_IREAD
78 # define S_IRUSR 00400
80 #if !S_IWUSR && S_IWRITE
81 # define S_IWUSR S_IWRITE
84 # define S_IWUSR 00200
86 #if !S_IXUSR && S_IEXEC
87 # define S_IXUSR S_IEXEC
90 # define S_IXUSR 00100
94 # define struct_stat64 struct stat64
96 # define struct_stat64 struct stat
97 # define __getpid getpid
98 # define __gettimeofday gettimeofday
99 # define __mkdir mkdir
101 # define __open64 open
102 # define __lxstat64(version, path, buf) lstat (path, buf)
103 # define __xstat64(version, path, buf) stat (path, buf)
106 #if ! (HAVE___SECURE_GETENV || _LIBC)
107 # define __secure_getenv getenv
111 # include <hp-timing.h>
113 # define RANDOM_BITS(Var) \
114 if (__builtin_expect (value == UINT64_C (0), 0)) \
116 /* If this is the first time this function is used initialize \
117 the variable we accumulate the value in to some somewhat \
118 random value. If we'd not do this programs at startup time \
119 might have a reduced set of possible names, at least on slow \
122 __gettimeofday (&tv, NULL); \
123 value = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec; \
129 /* Use the widest available unsigned type if uint64_t is not
130 available. The algorithm below extracts a number less than 62**6
131 (approximately 2**35.725) from uint64_t, so ancient hosts where
132 uintmax_t is only 32 bits lose about 3.725 bits of randomness,
133 which is better than not having mkstemp at all. */
134 #if !defined UINT64_MAX && !defined uint64_t
135 # define uint64_t uintmax_t
138 /* Return nonzero if DIR is an existent directory. */
140 direxists (const char *dir)
143 return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode);
146 /* Path search algorithm, for tmpnam, tmpfile, etc. If DIR is
147 non-null and exists, uses it; otherwise uses the first of $TMPDIR,
148 P_tmpdir, /tmp that exists. Copies into TMPL a template suitable
149 for use with mk[s]temp. Will fail (-1) if DIR is non-null and
150 doesn't exist, none of the searched dirs exists, or there's not
151 enough space in TMPL. */
153 __path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
173 d = __secure_getenv ("TMPDIR");
174 if (d != NULL && direxists (d))
176 else if (dir != NULL && direxists (dir))
183 if (direxists (P_tmpdir))
185 else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
189 __set_errno (ENOENT);
195 while (dlen > 1 && dir[dlen - 1] == '/')
196 dlen--; /* remove trailing slashes */
198 /* check we have room for "${dir}/${pfx}XXXXXX\0" */
199 if (tmpl_len < dlen + 1 + plen + 6 + 1)
201 __set_errno (EINVAL);
205 sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx);
209 /* These are the characters used in temporary filenames. */
210 static const char letters[] =
211 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
213 /* Generate a temporary file name based on TMPL. TMPL must match the
214 rules for mk[s]temp (i.e. end in "XXXXXX"). The name constructed
215 does not exist at the time of the call to __gen_tempname. TMPL is
216 overwritten with the result.
219 __GT_NOCREATE: simply verify that the name does not exist
220 at the time of the call.
221 __GT_FILE: create the file using open(O_CREAT|O_EXCL)
222 and return a read-write fd. The file is mode 0600.
223 __GT_BIGFILE: same as __GT_FILE but use open64().
224 __GT_DIR: create a directory, which will be mode 0700.
226 We use a clever algorithm to get hard-to-predict names. */
228 __gen_tempname (char *tmpl, int kind)
232 static uint64_t value;
233 uint64_t random_time_bits;
236 int save_errno = errno;
239 /* A lower bound on the number of temporary files to attempt to
240 generate. The maximum total number of temporary file names that
241 can exist for a given template is 62**6. It should never be
242 necessary to try all these combinations. Instead if a reasonable
243 number of names is tried (we define reasonable as 62**3) fail to
244 give the system administrator the chance to remove the problems. */
245 unsigned int attempts_min = 62 * 62 * 62;
247 /* The number of times to attempt to generate a temporary file. To
248 conform to POSIX, this must be no smaller than TMP_MAX. */
249 unsigned int attempts = attempts_min < TMP_MAX ? TMP_MAX : attempts_min;
252 if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX"))
254 __set_errno (EINVAL);
258 /* This is where the Xs start. */
259 XXXXXX = &tmpl[len - 6];
261 /* Get some more or less random data. */
263 RANDOM_BITS (random_time_bits);
265 # if HAVE_GETTIMEOFDAY || _LIBC
268 __gettimeofday (&tv, NULL);
269 random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;
272 random_time_bits = time (NULL);
275 value += random_time_bits ^ __getpid ();
277 for (count = 0; count < attempts; value += 7777, ++count)
281 /* Fill in the random bits. */
282 XXXXXX[0] = letters[v % 62];
284 XXXXXX[1] = letters[v % 62];
286 XXXXXX[2] = letters[v % 62];
288 XXXXXX[3] = letters[v % 62];
290 XXXXXX[4] = letters[v % 62];
292 XXXXXX[5] = letters[v % 62];
297 fd = __open (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
301 fd = __open64 (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
305 fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR);
309 /* This case is backward from the other three. __gen_tempname
310 succeeds if __xstat fails because the name does not exist.
311 Note the continue to bypass the common logic at the bottom
313 if (__lxstat64 (_STAT_VER, tmpl, &st) < 0)
317 __set_errno (save_errno);
327 assert (! "invalid KIND in __gen_tempname");
332 __set_errno (save_errno);
335 else if (errno != EEXIST)
339 /* We got out of the loop because we ran out of combinations to try. */
340 __set_errno (EEXIST);