]>
Commit | Line | Data |
---|---|---|
d614a753 | 1 | /* Copyright (C) 1991-2020 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 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
28f540f4 | 17 | |
c7aec4be | 18 | #if !_LIBC |
46c3f8cd | 19 | # include <config.h> |
c7aec4be | 20 | # include "tempname.h" |
46c3f8cd UD |
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 | |
d7e23b02 UD |
40 | # define __GT_DIR 1 |
41 | # define __GT_NOCREATE 2 | |
46c3f8cd | 42 | #endif |
c7aec4be WN |
43 | #if !_LIBC && (GT_FILE != __GT_FILE || GT_DIR != __GT_DIR \ |
44 | || GT_NOCREATE != __GT_NOCREATE) | |
45 | # error report this to bug-gnulib@gnu.org | |
46c3f8cd UD |
46 | #endif |
47 | ||
c7aec4be WN |
48 | #include <stddef.h> |
49 | #include <stdlib.h> | |
50 | #include <string.h> | |
46c3f8cd | 51 | |
c7aec4be | 52 | #include <fcntl.h> |
4a39c34c | 53 | #include <time.h> |
c7aec4be WN |
54 | #include <stdint.h> |
55 | #include <unistd.h> | |
46c3f8cd UD |
56 | |
57 | #include <sys/stat.h> | |
46c3f8cd UD |
58 | |
59 | #if _LIBC | |
60 | # define struct_stat64 struct stat64 | |
c7aec4be | 61 | # define __secure_getenv __libc_secure_getenv |
46c3f8cd UD |
62 | #else |
63 | # define struct_stat64 struct stat | |
c7aec4be | 64 | # define __gen_tempname gen_tempname |
46c3f8cd | 65 | # define __getpid getpid |
46c3f8cd UD |
66 | # define __mkdir mkdir |
67 | # define __open open | |
c7aec4be WN |
68 | # define __lxstat64(version, file, buf) lstat (file, buf) |
69 | # define __secure_getenv secure_getenv | |
46c3f8cd UD |
70 | #endif |
71 | ||
3b5c1b57 | 72 | #ifdef _LIBC |
359653aa AZ |
73 | # include <random-bits.h> |
74 | # define RANDOM_BITS(Var) ((Var) = random_bits ()) | |
75 | # else | |
76 | # define RANDOM_BITS(Var) \ | |
77 | { \ | |
4a39c34c ZW |
78 | struct timespec ts; \ |
79 | clock_gettime (CLOCK_REALTIME, &ts); \ | |
80 | (Var) = ((uint64_t) tv.tv_nsec << 16) ^ tv.tv_sec; \ | |
359653aa | 81 | } |
3b5c1b57 UD |
82 | #endif |
83 | ||
f2615995 UD |
84 | /* Use the widest available unsigned type if uint64_t is not |
85 | available. The algorithm below extracts a number less than 62**6 | |
86 | (approximately 2**35.725) from uint64_t, so ancient hosts where | |
87 | uintmax_t is only 32 bits lose about 3.725 bits of randomness, | |
88 | which is better than not having mkstemp at all. */ | |
89 | #if !defined UINT64_MAX && !defined uint64_t | |
90 | # define uint64_t uintmax_t | |
91 | #endif | |
92 | ||
c7aec4be | 93 | #if _LIBC |
28f540f4 RM |
94 | /* Return nonzero if DIR is an existent directory. */ |
95 | static int | |
7cabd57c | 96 | direxists (const char *dir) |
28f540f4 | 97 | { |
46c3f8cd | 98 | struct_stat64 buf; |
8edf6e0d | 99 | return __xstat64 (_STAT_VER, dir, &buf) == 0 && S_ISDIR (buf.st_mode); |
28f540f4 RM |
100 | } |
101 | ||
7cabd57c UD |
102 | /* Path search algorithm, for tmpnam, tmpfile, etc. If DIR is |
103 | non-null and exists, uses it; otherwise uses the first of $TMPDIR, | |
104 | P_tmpdir, /tmp that exists. Copies into TMPL a template suitable | |
105 | for use with mk[s]temp. Will fail (-1) if DIR is non-null and | |
106 | doesn't exist, none of the searched dirs exists, or there's not | |
107 | enough space in TMPL. */ | |
108 | int | |
60876a75 UD |
109 | __path_search (char *tmpl, size_t tmpl_len, const char *dir, const char *pfx, |
110 | int try_tmpdir) | |
28f540f4 | 111 | { |
7cabd57c UD |
112 | const char *d; |
113 | size_t dlen, plen; | |
114 | ||
115 | if (!pfx || !pfx[0]) | |
116 | { | |
117 | pfx = "file"; | |
118 | plen = 4; | |
119 | } | |
28f540f4 RM |
120 | else |
121 | { | |
7cabd57c UD |
122 | plen = strlen (pfx); |
123 | if (plen > 5) | |
124 | plen = 5; | |
28f540f4 | 125 | } |
28f540f4 | 126 | |
60876a75 UD |
127 | if (try_tmpdir) |
128 | { | |
c7aec4be | 129 | d = __secure_getenv ("TMPDIR"); |
60876a75 UD |
130 | if (d != NULL && direxists (d)) |
131 | dir = d; | |
132 | else if (dir != NULL && direxists (dir)) | |
133 | /* nothing */ ; | |
5a7cb1a2 UD |
134 | else |
135 | dir = NULL; | |
60876a75 | 136 | } |
e9dcb080 | 137 | if (dir == NULL) |
28f540f4 | 138 | { |
b61af6fc UD |
139 | if (direxists (P_tmpdir)) |
140 | dir = P_tmpdir; | |
141 | else if (strcmp (P_tmpdir, "/tmp") != 0 && direxists ("/tmp")) | |
142 | dir = "/tmp"; | |
143 | else | |
144 | { | |
145 | __set_errno (ENOENT); | |
146 | return -1; | |
147 | } | |
28f540f4 | 148 | } |
28f540f4 RM |
149 | |
150 | dlen = strlen (dir); | |
28f540f4 | 151 | while (dlen > 1 && dir[dlen - 1] == '/') |
7cabd57c | 152 | dlen--; /* remove trailing slashes */ |
28f540f4 | 153 | |
7cabd57c UD |
154 | /* check we have room for "${dir}/${pfx}XXXXXX\0" */ |
155 | if (tmpl_len < dlen + 1 + plen + 6 + 1) | |
28f540f4 | 156 | { |
7cabd57c UD |
157 | __set_errno (EINVAL); |
158 | return -1; | |
28f540f4 | 159 | } |
28f540f4 | 160 | |
04166d6e | 161 | sprintf (tmpl, "%.*s/%.*sXXXXXX", (int) dlen, dir, (int) plen, pfx); |
7cabd57c UD |
162 | return 0; |
163 | } | |
c7aec4be | 164 | #endif /* _LIBC */ |
7cabd57c | 165 | |
c7aec4be | 166 | /* These are the characters used in temporary file names. */ |
7cabd57c UD |
167 | static const char letters[] = |
168 | "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; | |
169 | ||
170 | /* Generate a temporary file name based on TMPL. TMPL must match the | |
7f3146e7 UD |
171 | rules for mk[s]temp (i.e. end in "XXXXXX", possibly with a suffix). |
172 | The name constructed does not exist at the time of the call to | |
173 | __gen_tempname. TMPL is overwritten with the result. | |
2e65ca2b UD |
174 | |
175 | KIND may be one of: | |
176 | __GT_NOCREATE: simply verify that the name does not exist | |
177 | at the time of the call. | |
178 | __GT_FILE: create the file using open(O_CREAT|O_EXCL) | |
179 | and return a read-write fd. The file is mode 0600. | |
2e65ca2b | 180 | __GT_DIR: create a directory, which will be mode 0700. |
7cabd57c UD |
181 | |
182 | We use a clever algorithm to get hard-to-predict names. */ | |
183 | int | |
7f3146e7 | 184 | __gen_tempname (char *tmpl, int suffixlen, int flags, int kind) |
7cabd57c UD |
185 | { |
186 | int len; | |
187 | char *XXXXXX; | |
8e9b2075 UD |
188 | unsigned int count; |
189 | int fd = -1; | |
7cabd57c | 190 | int save_errno = errno; |
46c3f8cd | 191 | struct_stat64 st; |
28f540f4 | 192 | |
8e9b2075 UD |
193 | /* A lower bound on the number of temporary files to attempt to |
194 | generate. The maximum total number of temporary file names that | |
195 | can exist for a given template is 62**6. It should never be | |
c7aec4be | 196 | necessary to try all of these combinations. Instead if a reasonable |
8e9b2075 UD |
197 | number of names is tried (we define reasonable as 62**3) fail to |
198 | give the system administrator the chance to remove the problems. */ | |
cec40916 | 199 | #define ATTEMPTS_MIN (62 * 62 * 62) |
8e9b2075 UD |
200 | |
201 | /* The number of times to attempt to generate a temporary file. To | |
202 | conform to POSIX, this must be no smaller than TMP_MAX. */ | |
cec40916 UD |
203 | #if ATTEMPTS_MIN < TMP_MAX |
204 | unsigned int attempts = TMP_MAX; | |
205 | #else | |
206 | unsigned int attempts = ATTEMPTS_MIN; | |
207 | #endif | |
8e9b2075 | 208 | |
7cabd57c | 209 | len = strlen (tmpl); |
7f3146e7 | 210 | if (len < 6 + suffixlen || memcmp (&tmpl[len - 6 - suffixlen], "XXXXXX", 6)) |
7cabd57c | 211 | { |
a7ab2023 | 212 | __set_errno (EINVAL); |
7cabd57c UD |
213 | return -1; |
214 | } | |
28f540f4 | 215 | |
7cabd57c | 216 | /* This is where the Xs start. */ |
7f3146e7 | 217 | XXXXXX = &tmpl[len - 6 - suffixlen]; |
d68171ed | 218 | |
e1df30fb AZ |
219 | uint64_t pid = (uint64_t) __getpid () << 32; |
220 | for (count = 0; count < attempts; ++count) | |
a7ab2023 | 221 | { |
e1df30fb AZ |
222 | uint64_t v; |
223 | /* Get some more or less random data. */ | |
224 | RANDOM_BITS (v); | |
225 | v ^= pid; | |
a7ab2023 UD |
226 | |
227 | /* Fill in the random bits. */ | |
228 | XXXXXX[0] = letters[v % 62]; | |
229 | v /= 62; | |
230 | XXXXXX[1] = letters[v % 62]; | |
231 | v /= 62; | |
232 | XXXXXX[2] = letters[v % 62]; | |
233 | v /= 62; | |
234 | XXXXXX[3] = letters[v % 62]; | |
235 | v /= 62; | |
236 | XXXXXX[4] = letters[v % 62]; | |
237 | v /= 62; | |
238 | XXXXXX[5] = letters[v % 62]; | |
28f540f4 | 239 | |
2e65ca2b | 240 | switch (kind) |
7cabd57c | 241 | { |
2e65ca2b | 242 | case __GT_FILE: |
d7e23b02 | 243 | fd = __open (tmpl, |
e8a32126 | 244 | (flags & ~O_ACCMODE) |
d7e23b02 | 245 | | O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR); |
2e65ca2b UD |
246 | break; |
247 | ||
248 | case __GT_DIR: | |
46c3f8cd | 249 | fd = __mkdir (tmpl, S_IRUSR | S_IWUSR | S_IXUSR); |
2e65ca2b UD |
250 | break; |
251 | ||
252 | case __GT_NOCREATE: | |
253 | /* This case is backward from the other three. __gen_tempname | |
254 | succeeds if __xstat fails because the name does not exist. | |
255 | Note the continue to bypass the common logic at the bottom | |
256 | of the loop. */ | |
72c65ff4 | 257 | if (__lxstat64 (_STAT_VER, tmpl, &st) < 0) |
7cabd57c UD |
258 | { |
259 | if (errno == ENOENT) | |
28f540f4 | 260 | { |
7cabd57c UD |
261 | __set_errno (save_errno); |
262 | return 0; | |
28f540f4 | 263 | } |
7cabd57c UD |
264 | else |
265 | /* Give up now. */ | |
266 | return -1; | |
28f540f4 | 267 | } |
2e65ca2b UD |
268 | continue; |
269 | ||
270 | default: | |
271 | assert (! "invalid KIND in __gen_tempname"); | |
c7aec4be | 272 | abort (); |
2e65ca2b UD |
273 | } |
274 | ||
275 | if (fd >= 0) | |
276 | { | |
277 | __set_errno (save_errno); | |
278 | return fd; | |
28f540f4 | 279 | } |
2e65ca2b UD |
280 | else if (errno != EEXIST) |
281 | return -1; | |
28f540f4 RM |
282 | } |
283 | ||
284 | /* We got out of the loop because we ran out of combinations to try. */ | |
7cabd57c UD |
285 | __set_errno (EEXIST); |
286 | return -1; | |
28f540f4 | 287 | } |