Mercurial > hg > octave-shane > gnulib-hg
annotate lib/tempname.c @ 4132:98b37cab8b76
More consistent inttypes.h / stdint.h handling.
author | Bruno Haible <bruno@clisp.org> |
---|---|
date | Mon, 06 Jan 2003 12:38:36 +0000 |
parents | 7158a1db8695 |
children | fcd34d3861a4 |
rev | line source |
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4020 | 1 /* tempname.c - generate the name of a temporary file. |
3192 | 2 |
4020 | 3 Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, |
4 2000, 2001, 2002 Free Software Foundation, Inc. | |
3192 | 5 |
4020 | 6 This program is free software; you can redistribute it and/or modify |
7 it under the terms of the GNU General Public License as published by | |
8 the Free Software Foundation; either version 2, or (at your option) | |
9 any later version. | |
3192 | 10 |
4020 | 11 This program is distributed in the hope that it will be useful, |
12 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 GNU General Public License for more details. | |
15 | |
16 You should have received a copy of the GNU General Public License along | |
17 with this program; if not, write to the Free Software Foundation, | |
18 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ | |
3192 | 19 |
20 #if HAVE_CONFIG_H | |
21 # include <config.h> | |
22 #endif | |
23 | |
24 #include <sys/types.h> | |
25 #include <assert.h> | |
26 | |
27 #include <errno.h> | |
28 #ifndef __set_errno | |
29 # define __set_errno(Val) errno = (Val) | |
30 #endif | |
31 | |
32 #include <stdio.h> | |
33 #ifndef P_tmpdir | |
34 # define P_tmpdir "/tmp" | |
35 #endif | |
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36 #ifndef TMP_MAX |
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37 # define TMP_MAX 238328 |
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38 #endif |
3192 | 39 #ifndef __GT_FILE |
40 # define __GT_FILE 0 | |
41 # define __GT_BIGFILE 1 | |
42 # define __GT_DIR 2 | |
43 # define __GT_NOCREATE 3 | |
44 #endif | |
45 | |
46 #if STDC_HEADERS || _LIBC | |
47 # include <stddef.h> | |
48 # include <string.h> | |
49 #endif | |
50 | |
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51 #include <stdlib.h> |
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52 |
3192 | 53 #if HAVE_FCNTL_H || _LIBC |
54 # include <fcntl.h> | |
55 #endif | |
56 | |
57 #if HAVE_SYS_TIME_H || _LIBC | |
58 # include <sys/time.h> | |
59 #endif | |
60 | |
61 #if HAVE_STDINT_H || _LIBC | |
62 # include <stdint.h> | |
63 #endif | |
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64 #if HAVE_INTTYPES_H |
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65 # include <inttypes.h> |
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66 #endif |
3192 | 67 |
68 #if HAVE_UNISTD_H || _LIBC | |
69 # include <unistd.h> | |
70 #endif | |
71 | |
72 #include <sys/stat.h> | |
73 #if STAT_MACROS_BROKEN | |
74 # undef S_ISDIR | |
75 #endif | |
76 #if !defined S_ISDIR && defined S_IFDIR | |
77 # define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR) | |
78 #endif | |
79 #if !S_IRUSR && S_IREAD | |
80 # define S_IRUSR S_IREAD | |
81 #endif | |
82 #if !S_IRUSR | |
83 # define S_IRUSR 00400 | |
84 #endif | |
85 #if !S_IWUSR && S_IWRITE | |
86 # define S_IWUSR S_IWRITE | |
87 #endif | |
88 #if !S_IWUSR | |
89 # define S_IWUSR 00200 | |
90 #endif | |
91 #if !S_IXUSR && S_IEXEC | |
92 # define S_IXUSR S_IEXEC | |
93 #endif | |
94 #if !S_IXUSR | |
95 # define S_IXUSR 00100 | |
96 #endif | |
97 | |
98 #if _LIBC | |
99 # define struct_stat64 struct stat64 | |
100 #else | |
101 # define struct_stat64 struct stat | |
102 # define __getpid getpid | |
103 # define __gettimeofday gettimeofday | |
104 # define __mkdir mkdir | |
105 # define __open open | |
106 # define __open64 open | |
107 # define __lxstat64(version, path, buf) lstat (path, buf) | |
108 # define __xstat64(version, path, buf) stat (path, buf) | |
109 #endif | |
110 | |
111 #if ! (HAVE___SECURE_GETENV || _LIBC) | |
112 # define __secure_getenv getenv | |
113 #endif | |
114 | |
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115 #ifdef _LIBC |
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116 # include <hp-timing.h> |
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117 # if HP_TIMING_AVAIL |
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118 # define RANDOM_BITS(Var) \ |
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119 if (__builtin_expect (value == UINT64_C (0), 0)) \ |
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120 { \ |
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121 /* If this is the first time this function is used initialize \ |
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122 the variable we accumulate the value in to some somewhat \ |
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123 random value. If we'd not do this programs at startup time \ |
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124 might have a reduced set of possible names, at least on slow \ |
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125 machines. */ \ |
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126 struct timeval tv; \ |
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127 __gettimeofday (&tv, NULL); \ |
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128 value = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec; \ |
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129 } \ |
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130 HP_TIMING_NOW (Var) |
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131 # endif |
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132 #endif |
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133 |
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134 /* Use the widest available unsigned type if uint64_t is not |
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135 available. The algorithm below extracts a number less than 62**6 |
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136 (approximately 2**35.725) from uint64_t, so ancient hosts where |
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137 uintmax_t is only 32 bits lose about 3.725 bits of randomness, |
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138 which is better than not having mkstemp at all. */ |
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139 #if !defined UINT64_MAX && !defined uint64_t |
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140 # define uint64_t uintmax_t |
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141 #endif |
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142 |
3192 | 143 /* Return nonzero if DIR is an existent directory. */ |
144 static int | |
145 direxists (const char *dir) | |
146 { | |
147 struct_stat64 buf; | |
148 return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode); | |
149 } | |
150 | |
151 /* Path search algorithm, for tmpnam, tmpfile, etc. If DIR is | |
152 non-null and exists, uses it; otherwise uses the first of $TMPDIR, | |
153 P_tmpdir, /tmp that exists. Copies into TMPL a template suitable | |
154 for use with mk[s]temp. Will fail (-1) if DIR is non-null and | |
155 doesn't exist, none of the searched dirs exists, or there's not | |
156 enough space in TMPL. */ | |
157 int | |
158 __path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx, | |
159 int try_tmpdir) | |
160 { | |
161 const char *d; | |
162 size_t dlen, plen; | |
163 | |
164 if (!pfx || !pfx[0]) | |
165 { | |
166 pfx = "file"; | |
167 plen = 4; | |
168 } | |
169 else | |
170 { | |
171 plen = strlen (pfx); | |
172 if (plen > 5) | |
173 plen = 5; | |
174 } | |
175 | |
176 if (try_tmpdir) | |
177 { | |
178 d = __secure_getenv ("TMPDIR"); | |
179 if (d != NULL && direxists (d)) | |
180 dir = d; | |
181 else if (dir != NULL && direxists (dir)) | |
182 /* nothing */ ; | |
183 else | |
184 dir = NULL; | |
185 } | |
186 if (dir == NULL) | |
187 { | |
188 if (direxists (P_tmpdir)) | |
189 dir = P_tmpdir; | |
190 else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp")) | |
191 dir = "/tmp"; | |
192 else | |
193 { | |
194 __set_errno (ENOENT); | |
195 return -1; | |
196 } | |
197 } | |
198 | |
199 dlen = strlen (dir); | |
200 while (dlen > 1 && dir[dlen - 1] == '/') | |
201 dlen--; /* remove trailing slashes */ | |
202 | |
203 /* check we have room for "${dir}/${pfx}XXXXXX\0" */ | |
204 if (tmpl_len < dlen + 1 + plen + 6 + 1) | |
205 { | |
206 __set_errno (EINVAL); | |
207 return -1; | |
208 } | |
209 | |
210 sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx); | |
211 return 0; | |
212 } | |
213 | |
214 /* These are the characters used in temporary filenames. */ | |
215 static const char letters[] = | |
216 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; | |
217 | |
218 /* Generate a temporary file name based on TMPL. TMPL must match the | |
219 rules for mk[s]temp (i.e. end in "XXXXXX"). The name constructed | |
220 does not exist at the time of the call to __gen_tempname. TMPL is | |
221 overwritten with the result. | |
222 | |
223 KIND may be one of: | |
224 __GT_NOCREATE: simply verify that the name does not exist | |
225 at the time of the call. | |
226 __GT_FILE: create the file using open(O_CREAT|O_EXCL) | |
227 and return a read-write fd. The file is mode 0600. | |
228 __GT_BIGFILE: same as __GT_FILE but use open64(). | |
229 __GT_DIR: create a directory, which will be mode 0700. | |
230 | |
231 We use a clever algorithm to get hard-to-predict names. */ | |
232 int | |
233 __gen_tempname (char *tmpl, int kind) | |
234 { | |
235 int len; | |
236 char *XXXXXX; | |
237 static uint64_t value; | |
238 uint64_t random_time_bits; | |
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239 unsigned int count; |
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240 int fd = -1; |
3192 | 241 int save_errno = errno; |
242 struct_stat64 st; | |
243 | |
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244 /* A lower bound on the number of temporary files to attempt to |
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245 generate. The maximum total number of temporary file names that |
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246 can exist for a given template is 62**6. It should never be |
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247 necessary to try all these combinations. Instead if a reasonable |
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248 number of names is tried (we define reasonable as 62**3) fail to |
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249 give the system administrator the chance to remove the problems. */ |
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250 unsigned int attempts_min = 62 * 62 * 62; |
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251 |
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252 /* The number of times to attempt to generate a temporary file. To |
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253 conform to POSIX, this must be no smaller than TMP_MAX. */ |
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254 unsigned int attempts = attempts_min < TMP_MAX ? TMP_MAX : attempts_min; |
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255 |
3192 | 256 len = strlen (tmpl); |
257 if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX")) | |
258 { | |
259 __set_errno (EINVAL); | |
260 return -1; | |
261 } | |
262 | |
263 /* This is where the Xs start. */ | |
264 XXXXXX = &tmpl[len - 6]; | |
265 | |
266 /* Get some more or less random data. */ | |
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267 #ifdef RANDOM_BITS |
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268 RANDOM_BITS (random_time_bits); |
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269 #else |
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270 # if HAVE_GETTIMEOFDAY || _LIBC |
3192 | 271 { |
272 struct timeval tv; | |
273 __gettimeofday (&tv, NULL); | |
274 random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec; | |
275 } | |
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276 # else |
3192 | 277 random_time_bits = time (NULL); |
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278 # endif |
3192 | 279 #endif |
280 value += random_time_bits ^ __getpid (); | |
281 | |
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282 for (count = 0; count < attempts; value += 7777, ++count) |
3192 | 283 { |
284 uint64_t v = value; | |
285 | |
286 /* Fill in the random bits. */ | |
287 XXXXXX[0] = letters[v % 62]; | |
288 v /= 62; | |
289 XXXXXX[1] = letters[v % 62]; | |
290 v /= 62; | |
291 XXXXXX[2] = letters[v % 62]; | |
292 v /= 62; | |
293 XXXXXX[3] = letters[v % 62]; | |
294 v /= 62; | |
295 XXXXXX[4] = letters[v % 62]; | |
296 v /= 62; | |
297 XXXXXX[5] = letters[v % 62]; | |
298 | |
299 switch (kind) | |
300 { | |
301 case __GT_FILE: | |
302 fd = __open (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR); | |
303 break; | |
304 | |
305 case __GT_BIGFILE: | |
306 fd = __open64 (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR); | |
307 break; | |
308 | |
309 case __GT_DIR: | |
310 fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR); | |
311 break; | |
312 | |
313 case __GT_NOCREATE: | |
314 /* This case is backward from the other three. __gen_tempname | |
315 succeeds if __xstat fails because the name does not exist. | |
316 Note the continue to bypass the common logic at the bottom | |
317 of the loop. */ | |
318 if (__lxstat64 (_STAT_VER, tmpl, &st) < 0) | |
319 { | |
320 if (errno == ENOENT) | |
321 { | |
322 __set_errno (save_errno); | |
323 return 0; | |
324 } | |
325 else | |
326 /* Give up now. */ | |
327 return -1; | |
328 } | |
329 continue; | |
330 | |
331 default: | |
332 assert (! "invalid KIND in __gen_tempname"); | |
333 } | |
334 | |
335 if (fd >= 0) | |
336 { | |
337 __set_errno (save_errno); | |
338 return fd; | |
339 } | |
340 else if (errno != EEXIST) | |
341 return -1; | |
342 } | |
343 | |
344 /* We got out of the loop because we ran out of combinations to try. */ | |
345 __set_errno (EEXIST); | |
346 return -1; | |
347 } |