Mercurial > hg > octave-shane > gnulib-hg
annotate lib/tempname.c @ 4554:5a1e7c84e9cd
Use three spaces, rather than tab, after '#'
in shell-script copyright notices.
Suggested by Bruno Haible.
| author | Paul Eggert <eggert@cs.ucla.edu> |
|---|---|
| date | Fri, 15 Aug 2003 18:04:34 +0000 |
| parents | fcd34d3861a4 |
| children | ce37d22a271f |
| rev | line source |
|---|---|
| 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, |
| 4333 | 4 2000, 2001, 2002, 2003 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 | |
| 4333 | 46 #include <stddef.h> |
| 47 | |
| 3192 | 48 #if STDC_HEADERS || _LIBC |
| 49 # include <string.h> | |
| 50 #endif | |
| 51 | |
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52 #include <stdlib.h> |
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53 |
| 3192 | 54 #if HAVE_FCNTL_H || _LIBC |
| 55 # include <fcntl.h> | |
| 56 #endif | |
| 57 | |
| 58 #if HAVE_SYS_TIME_H || _LIBC | |
| 59 # include <sys/time.h> | |
| 60 #endif | |
| 61 | |
| 62 #if HAVE_STDINT_H || _LIBC | |
| 63 # include <stdint.h> | |
| 64 #endif | |
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65 #if HAVE_INTTYPES_H |
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66 # include <inttypes.h> |
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67 #endif |
| 3192 | 68 |
| 69 #if HAVE_UNISTD_H || _LIBC | |
| 70 # include <unistd.h> | |
| 71 #endif | |
| 72 | |
| 73 #include <sys/stat.h> | |
| 74 #if STAT_MACROS_BROKEN | |
| 75 # undef S_ISDIR | |
| 76 #endif | |
| 77 #if !defined S_ISDIR && defined S_IFDIR | |
| 78 # define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR) | |
| 79 #endif | |
| 80 #if !S_IRUSR && S_IREAD | |
| 81 # define S_IRUSR S_IREAD | |
| 82 #endif | |
| 83 #if !S_IRUSR | |
| 84 # define S_IRUSR 00400 | |
| 85 #endif | |
| 86 #if !S_IWUSR && S_IWRITE | |
| 87 # define S_IWUSR S_IWRITE | |
| 88 #endif | |
| 89 #if !S_IWUSR | |
| 90 # define S_IWUSR 00200 | |
| 91 #endif | |
| 92 #if !S_IXUSR && S_IEXEC | |
| 93 # define S_IXUSR S_IEXEC | |
| 94 #endif | |
| 95 #if !S_IXUSR | |
| 96 # define S_IXUSR 00100 | |
| 97 #endif | |
| 98 | |
| 99 #if _LIBC | |
| 100 # define struct_stat64 struct stat64 | |
| 101 #else | |
| 102 # define struct_stat64 struct stat | |
| 103 # define __getpid getpid | |
| 104 # define __gettimeofday gettimeofday | |
| 105 # define __mkdir mkdir | |
| 106 # define __open open | |
| 107 # define __open64 open | |
| 108 # define __lxstat64(version, path, buf) lstat (path, buf) | |
| 109 # define __xstat64(version, path, buf) stat (path, buf) | |
| 110 #endif | |
| 111 | |
| 112 #if ! (HAVE___SECURE_GETENV || _LIBC) | |
| 113 # define __secure_getenv getenv | |
| 114 #endif | |
| 115 | |
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116 #ifdef _LIBC |
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117 # include <hp-timing.h> |
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118 # if HP_TIMING_AVAIL |
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119 # define RANDOM_BITS(Var) \ |
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120 if (__builtin_expect (value == UINT64_C (0), 0)) \ |
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121 { \ |
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122 /* If this is the first time this function is used initialize \ |
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123 the variable we accumulate the value in to some somewhat \ |
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124 random value. If we'd not do this programs at startup time \ |
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125 might have a reduced set of possible names, at least on slow \ |
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126 machines. */ \ |
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127 struct timeval tv; \ |
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128 __gettimeofday (&tv, NULL); \ |
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129 value = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec; \ |
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130 } \ |
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131 HP_TIMING_NOW (Var) |
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132 # endif |
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133 #endif |
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134 |
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135 /* Use the widest available unsigned type if uint64_t is not |
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136 available. The algorithm below extracts a number less than 62**6 |
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137 (approximately 2**35.725) from uint64_t, so ancient hosts where |
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138 uintmax_t is only 32 bits lose about 3.725 bits of randomness, |
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139 which is better than not having mkstemp at all. */ |
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140 #if !defined UINT64_MAX && !defined uint64_t |
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141 # define uint64_t uintmax_t |
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142 #endif |
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143 |
| 3192 | 144 /* Return nonzero if DIR is an existent directory. */ |
| 145 static int | |
| 146 direxists (const char *dir) | |
| 147 { | |
| 148 struct_stat64 buf; | |
| 149 return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode); | |
| 150 } | |
| 151 | |
| 152 /* Path search algorithm, for tmpnam, tmpfile, etc. If DIR is | |
| 153 non-null and exists, uses it; otherwise uses the first of $TMPDIR, | |
| 154 P_tmpdir, /tmp that exists. Copies into TMPL a template suitable | |
| 155 for use with mk[s]temp. Will fail (-1) if DIR is non-null and | |
| 156 doesn't exist, none of the searched dirs exists, or there's not | |
| 157 enough space in TMPL. */ | |
| 158 int | |
| 159 __path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx, | |
| 160 int try_tmpdir) | |
| 161 { | |
| 162 const char *d; | |
| 163 size_t dlen, plen; | |
| 164 | |
| 165 if (!pfx || !pfx[0]) | |
| 166 { | |
| 167 pfx = "file"; | |
| 168 plen = 4; | |
| 169 } | |
| 170 else | |
| 171 { | |
| 172 plen = strlen (pfx); | |
| 173 if (plen > 5) | |
| 174 plen = 5; | |
| 175 } | |
| 176 | |
| 177 if (try_tmpdir) | |
| 178 { | |
| 179 d = __secure_getenv ("TMPDIR"); | |
| 180 if (d != NULL && direxists (d)) | |
| 181 dir = d; | |
| 182 else if (dir != NULL && direxists (dir)) | |
| 183 /* nothing */ ; | |
| 184 else | |
| 185 dir = NULL; | |
| 186 } | |
| 187 if (dir == NULL) | |
| 188 { | |
| 189 if (direxists (P_tmpdir)) | |
| 190 dir = P_tmpdir; | |
| 191 else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp")) | |
| 192 dir = "/tmp"; | |
| 193 else | |
| 194 { | |
| 195 __set_errno (ENOENT); | |
| 196 return -1; | |
| 197 } | |
| 198 } | |
| 199 | |
| 200 dlen = strlen (dir); | |
| 201 while (dlen > 1 && dir[dlen - 1] == '/') | |
| 202 dlen--; /* remove trailing slashes */ | |
| 203 | |
| 204 /* check we have room for "${dir}/${pfx}XXXXXX\0" */ | |
| 205 if (tmpl_len < dlen + 1 + plen + 6 + 1) | |
| 206 { | |
| 207 __set_errno (EINVAL); | |
| 208 return -1; | |
| 209 } | |
| 210 | |
| 211 sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx); | |
| 212 return 0; | |
| 213 } | |
| 214 | |
| 215 /* These are the characters used in temporary filenames. */ | |
| 216 static const char letters[] = | |
| 217 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; | |
| 218 | |
| 219 /* Generate a temporary file name based on TMPL. TMPL must match the | |
| 220 rules for mk[s]temp (i.e. end in "XXXXXX"). The name constructed | |
| 221 does not exist at the time of the call to __gen_tempname. TMPL is | |
| 222 overwritten with the result. | |
| 223 | |
| 224 KIND may be one of: | |
| 225 __GT_NOCREATE: simply verify that the name does not exist | |
| 226 at the time of the call. | |
| 227 __GT_FILE: create the file using open(O_CREAT|O_EXCL) | |
| 228 and return a read-write fd. The file is mode 0600. | |
| 229 __GT_BIGFILE: same as __GT_FILE but use open64(). | |
| 230 __GT_DIR: create a directory, which will be mode 0700. | |
| 231 | |
| 232 We use a clever algorithm to get hard-to-predict names. */ | |
| 233 int | |
| 234 __gen_tempname (char *tmpl, int kind) | |
| 235 { | |
| 236 int len; | |
| 237 char *XXXXXX; | |
| 238 static uint64_t value; | |
| 239 uint64_t random_time_bits; | |
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240 unsigned int count; |
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241 int fd = -1; |
| 3192 | 242 int save_errno = errno; |
| 243 struct_stat64 st; | |
| 244 | |
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245 /* A lower bound on the number of temporary files to attempt to |
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246 generate. The maximum total number of temporary file names that |
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247 can exist for a given template is 62**6. It should never be |
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248 necessary to try all these combinations. Instead if a reasonable |
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249 number of names is tried (we define reasonable as 62**3) fail to |
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250 give the system administrator the chance to remove the problems. */ |
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251 unsigned int attempts_min = 62 * 62 * 62; |
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252 |
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253 /* The number of times to attempt to generate a temporary file. To |
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254 conform to POSIX, this must be no smaller than TMP_MAX. */ |
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255 unsigned int attempts = attempts_min < TMP_MAX ? TMP_MAX : attempts_min; |
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256 |
| 3192 | 257 len = strlen (tmpl); |
| 258 if (len < 6 || strcmp (&tmpl[len - 6], "XXXXXX")) | |
| 259 { | |
| 260 __set_errno (EINVAL); | |
| 261 return -1; | |
| 262 } | |
| 263 | |
| 264 /* This is where the Xs start. */ | |
| 265 XXXXXX = &tmpl[len - 6]; | |
| 266 | |
| 267 /* Get some more or less random data. */ | |
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268 #ifdef RANDOM_BITS |
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269 RANDOM_BITS (random_time_bits); |
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270 #else |
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271 # if HAVE_GETTIMEOFDAY || _LIBC |
| 3192 | 272 { |
| 273 struct timeval tv; | |
| 274 __gettimeofday (&tv, NULL); | |
| 275 random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec; | |
| 276 } | |
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277 # else |
| 3192 | 278 random_time_bits = time (NULL); |
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279 # endif |
| 3192 | 280 #endif |
| 281 value += random_time_bits ^ __getpid (); | |
| 282 | |
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283 for (count = 0; count < attempts; value += 7777, ++count) |
| 3192 | 284 { |
| 285 uint64_t v = value; | |
| 286 | |
| 287 /* Fill in the random bits. */ | |
| 288 XXXXXX[0] = letters[v % 62]; | |
| 289 v /= 62; | |
| 290 XXXXXX[1] = letters[v % 62]; | |
| 291 v /= 62; | |
| 292 XXXXXX[2] = letters[v % 62]; | |
| 293 v /= 62; | |
| 294 XXXXXX[3] = letters[v % 62]; | |
| 295 v /= 62; | |
| 296 XXXXXX[4] = letters[v % 62]; | |
| 297 v /= 62; | |
| 298 XXXXXX[5] = letters[v % 62]; | |
| 299 | |
| 300 switch (kind) | |
| 301 { | |
| 302 case __GT_FILE: | |
| 303 fd = __open (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR); | |
| 304 break; | |
| 305 | |
| 306 case __GT_BIGFILE: | |
| 307 fd = __open64 (tmpl, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR); | |
| 308 break; | |
| 309 | |
| 310 case __GT_DIR: | |
| 311 fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR); | |
| 312 break; | |
| 313 | |
| 314 case __GT_NOCREATE: | |
| 315 /* This case is backward from the other three. __gen_tempname | |
| 316 succeeds if __xstat fails because the name does not exist. | |
| 317 Note the continue to bypass the common logic at the bottom | |
| 318 of the loop. */ | |
| 319 if (__lxstat64 (_STAT_VER, tmpl, &st) < 0) | |
| 320 { | |
| 321 if (errno == ENOENT) | |
| 322 { | |
| 323 __set_errno (save_errno); | |
| 324 return 0; | |
| 325 } | |
| 326 else | |
| 327 /* Give up now. */ | |
| 328 return -1; | |
| 329 } | |
| 330 continue; | |
| 331 | |
| 332 default: | |
| 333 assert (! "invalid KIND in __gen_tempname"); | |
| 334 } | |
| 335 | |
| 336 if (fd >= 0) | |
| 337 { | |
| 338 __set_errno (save_errno); | |
| 339 return fd; | |
| 340 } | |
| 341 else if (errno != EEXIST) | |
| 342 return -1; | |
| 343 } | |
| 344 | |
| 345 /* We got out of the loop because we ran out of combinations to try. */ | |
| 346 __set_errno (EEXIST); | |
| 347 return -1; | |
| 348 } |