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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 |
41bdb6e2 AJ |
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 | |
478b92f0 UD |
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 | |
41bdb6e2 AJ |
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 | |
46c3f8cd UD |
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 | |
46c3f8cd UD |
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 | ||
3b5c1b57 UD |
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 | ||
f2615995 UD |
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 | ||
28f540f4 RM |
138 | /* Return nonzero if DIR is an existent directory. */ |
139 | static int | |
7cabd57c | 140 | direxists (const char *dir) |
28f540f4 | 141 | { |
46c3f8cd | 142 | struct_stat64 buf; |
8edf6e0d | 143 | return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode); |
28f540f4 RM |
144 | } |
145 | ||
7cabd57c UD |
146 | /* Path search algorithm, for tmpnam, tmpfile, etc. If DIR is |
147 | non-null and exists, uses it; otherwise uses the first of $TMPDIR, | |
148 | P_tmpdir, /tmp that exists. Copies into TMPL a template suitable | |
149 | for use with mk[s]temp. Will fail (-1) if DIR is non-null and | |
150 | doesn't exist, none of the searched dirs exists, or there's not | |
151 | enough space in TMPL. */ | |
152 | int | |
60876a75 UD |
153 | __path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx, |
154 | int try_tmpdir) | |
28f540f4 | 155 | { |
7cabd57c UD |
156 | const char *d; |
157 | size_t dlen, plen; | |
158 | ||
159 | if (!pfx || !pfx[0]) | |
160 | { | |
161 | pfx = "file"; | |
162 | plen = 4; | |
163 | } | |
28f540f4 RM |
164 | else |
165 | { | |
7cabd57c UD |
166 | plen = strlen (pfx); |
167 | if (plen > 5) | |
168 | plen = 5; | |
28f540f4 | 169 | } |
28f540f4 | 170 | |
60876a75 UD |
171 | if (try_tmpdir) |
172 | { | |
173 | d = __secure_getenv ("TMPDIR"); | |
174 | if (d != NULL && direxists (d)) | |
175 | dir = d; | |
176 | else if (dir != NULL && direxists (dir)) | |
177 | /* nothing */ ; | |
5a7cb1a2 UD |
178 | else |
179 | dir = NULL; | |
60876a75 | 180 | } |
e9dcb080 | 181 | if (dir == NULL) |
28f540f4 | 182 | { |
b61af6fc UD |
183 | if (direxists (P_tmpdir)) |
184 | dir = P_tmpdir; | |
185 | else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp")) | |
186 | dir = "/tmp"; | |
187 | else | |
188 | { | |
189 | __set_errno (ENOENT); | |
190 | return -1; | |
191 | } | |
28f540f4 | 192 | } |
28f540f4 RM |
193 | |
194 | dlen = strlen (dir); | |
28f540f4 | 195 | while (dlen > 1 && dir[dlen - 1] == '/') |
7cabd57c | 196 | dlen--; /* remove trailing slashes */ |
28f540f4 | 197 | |
7cabd57c UD |
198 | /* check we have room for "${dir}/${pfx}XXXXXX\0" */ |
199 | if (tmpl_len < dlen + 1 + plen + 6 + 1) | |
28f540f4 | 200 | { |
7cabd57c UD |
201 | __set_errno (EINVAL); |
202 | return -1; | |
28f540f4 | 203 | } |
28f540f4 | 204 | |
04166d6e | 205 | sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx); |
7cabd57c UD |
206 | return 0; |
207 | } | |
208 | ||
209 | /* These are the characters used in temporary filenames. */ | |
210 | static 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 | |
2e65ca2b UD |
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. | |
7cabd57c UD |
225 | |
226 | We use a clever algorithm to get hard-to-predict names. */ | |
227 | int | |
2e65ca2b | 228 | __gen_tempname (char *tmpl, int kind) |
7cabd57c UD |
229 | { |
230 | int len; | |
231 | char *XXXXXX; | |
232 | static uint64_t value; | |
46c3f8cd | 233 | uint64_t random_time_bits; |
8e9b2075 UD |
234 | unsigned int count; |
235 | int fd = -1; | |
7cabd57c | 236 | int save_errno = errno; |
46c3f8cd | 237 | struct_stat64 st; |
28f540f4 | 238 | |
8e9b2075 UD |
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; |
8e9b2075 UD |
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 | |
7cabd57c UD |
251 | len = strlen (tmpl); |
252 | if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX")) | |
253 | { | |
a7ab2023 | 254 | __set_errno (EINVAL); |
7cabd57c UD |
255 | return -1; |
256 | } | |
28f540f4 | 257 | |
7cabd57c UD |
258 | /* This is where the Xs start. */ |
259 | XXXXXX = &tmpl[len - 6]; | |
d68171ed | 260 | |
a7ab2023 | 261 | /* Get some more or less random data. */ |
f2615995 UD |
262 | #ifdef RANDOM_BITS |
263 | RANDOM_BITS (random_time_bits); | |
264 | #else | |
265 | # if HAVE_GETTIMEOFDAY || _LIBC | |
46c3f8cd UD |
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 |
46c3f8cd UD |
274 | #endif |
275 | value += random_time_bits ^ __getpid (); | |
28f540f4 | 276 | |
8e9b2075 | 277 | for (count = 0; count < attempts; value += 7777, ++count) |
a7ab2023 UD |
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); |
2e65ca2b UD |
298 | break; |
299 | ||
300 | case __GT_BIGFILE: | |
46c3f8cd | 301 | fd = __open64 (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR); |
2e65ca2b UD |
302 | break; |
303 | ||
304 | case __GT_DIR: | |
46c3f8cd | 305 | fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR); |
2e65ca2b UD |
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) |
7cabd57c UD |
314 | { |
315 | if (errno == ENOENT) | |
28f540f4 | 316 | { |
7cabd57c UD |
317 | __set_errno (save_errno); |
318 | return 0; | |
28f540f4 | 319 | } |
7cabd57c UD |
320 | else |
321 | /* Give up now. */ | |
322 | return -1; | |
28f540f4 | 323 | } |
2e65ca2b UD |
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 | } |
2e65ca2b UD |
335 | else if (errno != EEXIST) |
336 | return -1; | |
28f540f4 RM |
337 | } |
338 | ||
339 | /* We got out of the loop because we ran out of combinations to try. */ | |
7cabd57c UD |
340 | __set_errno (EEXIST); |
341 | return -1; | |
28f540f4 | 342 | } |