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a334319f 1/* Copyright (C) 1991-1999, 2000, 2001 Free Software Foundation, Inc.
478b92f0 2 This file is part of the GNU C Library.
28f540f4 3
478b92f0 4 The GNU C Library is free software; you can redistribute it and/or
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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.
28f540f4 8
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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
41bdb6e2 12 Lesser General Public License for more details.
28f540f4 13
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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
17 02111-1307 USA. */
28f540f4 18
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19#if HAVE_CONFIG_H
20# include <config.h>
21#endif
22
28f540f4 23#include <sys/types.h>
2e65ca2b 24#include <assert.h>
28f540f4 25
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26#include <errno.h>
27#ifndef __set_errno
28# define __set_errno(Val) errno = (Val)
29#endif
30
31#include <stdio.h>
32#ifndef P_tmpdir
33# define P_tmpdir "/tmp"
34#endif
35#ifndef TMP_MAX
36# define TMP_MAX 238328
37#endif
38#ifndef __GT_FILE
39# define __GT_FILE 0
40# define __GT_BIGFILE 1
41# define __GT_DIR 2
42# define __GT_NOCREATE 3
43#endif
44
45#if STDC_HEADERS || _LIBC
46# include <stddef.h>
47# include <stdlib.h>
48# include <string.h>
49#endif
50
51#if HAVE_FCNTL_H || _LIBC
52# include <fcntl.h>
53#endif
54
55#if HAVE_SYS_TIME_H || _LIBC
56# include <sys/time.h>
57#endif
58
59#if HAVE_STDINT_H || _LIBC
60# include <stdint.h>
61#endif
62
63#if HAVE_UNISTD_H || _LIBC
64# include <unistd.h>
65#endif
66
67#include <sys/stat.h>
68#if STAT_MACROS_BROKEN
69# undef S_ISDIR
70#endif
71#if !defined S_ISDIR && defined S_IFDIR
72# define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
73#endif
74#if !S_IRUSR && S_IREAD
75# define S_IRUSR S_IREAD
76#endif
77#if !S_IRUSR
78# define S_IRUSR 00400
79#endif
80#if !S_IWUSR && S_IWRITE
81# define S_IWUSR S_IWRITE
82#endif
83#if !S_IWUSR
84# define S_IWUSR 00200
85#endif
86#if !S_IXUSR && S_IEXEC
87# define S_IXUSR S_IEXEC
88#endif
89#if !S_IXUSR
90# define S_IXUSR 00100
91#endif
92
93#if _LIBC
94# define struct_stat64 struct stat64
95#else
96# define struct_stat64 struct stat
97# define __getpid getpid
98# define __gettimeofday gettimeofday
99# define __mkdir mkdir
100# define __open open
101# define __open64 open
102# define __lxstat64(version, path, buf) lstat (path, buf)
103# define __xstat64(version, path, buf) stat (path, buf)
104#endif
105
106#if ! (HAVE___SECURE_GETENV || _LIBC)
107# define __secure_getenv getenv
108#endif
109
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110#ifdef _LIBC
111# include <hp-timing.h>
112# if HP_TIMING_AVAIL
113# define RANDOM_BITS(Var) \
114 if (__builtin_expect (value == UINT64_C (0), 0)) \
115 { \
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 \
120 machines. */ \
121 struct timeval tv; \
122 __gettimeofday (&tv, NULL); \
123 value = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec; \
124 } \
125 HP_TIMING_NOW (Var)
126# endif
127#endif
128
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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
136#endif
137
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138/* Return nonzero if DIR is an existent directory. */
139static int
7cabd57c 140direxists (const char *dir)
28f540f4 141{
46c3f8cd 142 struct_stat64 buf;
8edf6e0d 143 return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode);
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144}
145
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146/* Path search algorithm, for tmpnam, tmpfile, etc. If DIR is
147 non-null and exists, uses it; otherwise uses the first of $TMPDIR,
148 P_tmpdir, /tmp that exists. Copies into TMPL a template suitable
149 for use with mk[s]temp. Will fail (-1) if DIR is non-null and
150 doesn't exist, none of the searched dirs exists, or there's not
151 enough space in TMPL. */
152int
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153__path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx,
154 int try_tmpdir)
28f540f4 155{
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156 const char *d;
157 size_t dlen, plen;
158
159 if (!pfx || !pfx[0])
160 {
161 pfx = "file";
162 plen = 4;
163 }
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164 else
165 {
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166 plen = strlen (pfx);
167 if (plen > 5)
168 plen = 5;
28f540f4 169 }
28f540f4 170
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171 if (try_tmpdir)
172 {
173 d = __secure_getenv ("TMPDIR");
174 if (d != NULL && direxists (d))
175 dir = d;
176 else if (dir != NULL && direxists (dir))
177 /* nothing */ ;
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178 else
179 dir = NULL;
60876a75 180 }
e9dcb080 181 if (dir == NULL)
28f540f4 182 {
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183 if (direxists (P_tmpdir))
184 dir = P_tmpdir;
185 else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp"))
186 dir = "/tmp";
187 else
188 {
189 __set_errno (ENOENT);
190 return -1;
191 }
28f540f4 192 }
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193
194 dlen = strlen (dir);
28f540f4 195 while (dlen > 1 && dir[dlen - 1] == '/')
7cabd57c 196 dlen--; /* remove trailing slashes */
28f540f4 197
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198 /* check we have room for "${dir}/${pfx}XXXXXX\0" */
199 if (tmpl_len < dlen + 1 + plen + 6 + 1)
28f540f4 200 {
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201 __set_errno (EINVAL);
202 return -1;
28f540f4 203 }
28f540f4 204
04166d6e 205 sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx);
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206 return 0;
207}
208
209/* These are the characters used in temporary filenames. */
210static const char letters[] =
211"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
212
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
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216 overwritten with the result.
217
218 KIND may be one of:
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.
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225
226 We use a clever algorithm to get hard-to-predict names. */
227int
2e65ca2b 228__gen_tempname (char *tmpl, int kind)
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229{
230 int len;
231 char *XXXXXX;
232 static uint64_t value;
46c3f8cd 233 uint64_t random_time_bits;
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234 unsigned int count;
235 int fd = -1;
7cabd57c 236 int save_errno = errno;
46c3f8cd 237 struct_stat64 st;
28f540f4 238
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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. */
a334319f 245 unsigned int attempts_min = 62 * 62 * 62;
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246
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. */
a334319f 249 unsigned int attempts = attempts_min < TMP_MAX ? TMP_MAX : attempts_min;
8e9b2075 250
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251 len = strlen (tmpl);
252 if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX"))
253 {
a7ab2023 254 __set_errno (EINVAL);
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255 return -1;
256 }
28f540f4 257
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258 /* This is where the Xs start. */
259 XXXXXX = &tmpl[len - 6];
d68171ed 260
a7ab2023 261 /* Get some more or less random data. */
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262#ifdef RANDOM_BITS
263 RANDOM_BITS (random_time_bits);
264#else
265# if HAVE_GETTIMEOFDAY || _LIBC
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266 {
267 struct timeval tv;
268 __gettimeofday (&tv, NULL);
269 random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;
270 }
f2615995 271# else
46c3f8cd 272 random_time_bits = time (NULL);
f2615995 273# endif
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274#endif
275 value += random_time_bits ^ __getpid ();
28f540f4 276
8e9b2075 277 for (count = 0; count < attempts; value += 7777, ++count)
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278 {
279 uint64_t v = value;
280
281 /* Fill in the random bits. */
282 XXXXXX[0] = letters[v % 62];
283 v /= 62;
284 XXXXXX[1] = letters[v % 62];
285 v /= 62;
286 XXXXXX[2] = letters[v % 62];
287 v /= 62;
288 XXXXXX[3] = letters[v % 62];
289 v /= 62;
290 XXXXXX[4] = letters[v % 62];
291 v /= 62;
292 XXXXXX[5] = letters[v % 62];
28f540f4 293
2e65ca2b 294 switch (kind)
7cabd57c 295 {
2e65ca2b 296 case __GT_FILE:
46c3f8cd 297 fd = __open (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
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298 break;
299
300 case __GT_BIGFILE:
46c3f8cd 301 fd = __open64 (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
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302 break;
303
304 case __GT_DIR:
46c3f8cd 305 fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR);
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306 break;
307
308 case __GT_NOCREATE:
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
312 of the loop. */
72c65ff4 313 if (__lxstat64 (_STAT_VER, tmpl, &st) < 0)
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314 {
315 if (errno == ENOENT)
28f540f4 316 {
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317 __set_errno (save_errno);
318 return 0;
28f540f4 319 }
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320 else
321 /* Give up now. */
322 return -1;
28f540f4 323 }
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324 continue;
325
326 default:
327 assert (! "invalid KIND in __gen_tempname");
328 }
329
330 if (fd >= 0)
331 {
332 __set_errno (save_errno);
333 return fd;
28f540f4 334 }
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335 else if (errno != EEXIST)
336 return -1;
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337 }
338
339 /* We got out of the loop because we ran out of combinations to try. */
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340 __set_errno (EEXIST);
341 return -1;
28f540f4 342}