Commit | Line | Data |
---|---|---|
2f1de3dd | 1 | /* update-game-score.c --- Update a score file |
294981c7 | 2 | |
acaf905b | 3 | Copyright (C) 2002-2012 Free Software Foundation, Inc. |
294981c7 GM |
4 | |
5 | Author: Colin Walters <walters@debian.org> | |
2f1de3dd CW |
6 | |
7 | This file is part of GNU Emacs. | |
8 | ||
294981c7 | 9 | GNU Emacs is free software: you can redistribute it and/or modify |
2f1de3dd | 10 | it under the terms of the GNU General Public License as published by |
294981c7 GM |
11 | the Free Software Foundation, either version 3 of the License, or |
12 | (at your option) any later version. | |
2f1de3dd CW |
13 | |
14 | GNU Emacs is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
294981c7 GM |
20 | along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ |
21 | ||
2f1de3dd | 22 | |
89cc1591 | 23 | /* This program allows a game to securely and atomically update a |
8eec804f CW |
24 | score file. It should be installed setuid, owned by an appropriate |
25 | user like `games'. | |
26 | ||
27 | Alternatively, it can be compiled without HAVE_SHARED_GAME_DIR | |
28 | defined, and in that case it will store scores in the user's home | |
29 | directory (it should NOT be setuid). | |
2f1de3dd | 30 | |
294981c7 | 31 | Created 2002/03/22. |
2f1de3dd CW |
32 | */ |
33 | ||
c42d6dbd EZ |
34 | #include <config.h> |
35 | ||
2f1de3dd CW |
36 | #include <unistd.h> |
37 | #include <errno.h> | |
0c6d656d | 38 | #include <limits.h> |
2f1de3dd CW |
39 | #include <string.h> |
40 | #include <stdlib.h> | |
41 | #include <stdio.h> | |
42 | #include <time.h> | |
cd553ffb | 43 | #include <pwd.h> |
2f1de3dd | 44 | #include <ctype.h> |
5b400482 | 45 | #ifdef HAVE_FCNTL_H |
2f1de3dd | 46 | #include <fcntl.h> |
5b400482 | 47 | #endif |
2f1de3dd | 48 | #include <sys/stat.h> |
15142f27 | 49 | #include <getopt.h> |
5b400482 | 50 | |
2f1de3dd | 51 | #define MAX_ATTEMPTS 5 |
8eec804f CW |
52 | #define MAX_SCORES 200 |
53 | #define MAX_DATA_LEN 1024 | |
5795b420 | 54 | |
1d28afaf DL |
55 | #ifndef HAVE_DIFFTIME |
56 | /* OK on POSIX (time_t is arithmetic type) modulo overflow in subtraction. */ | |
57 | #define difftime(t1, t0) (double)((t1) - (t0)) | |
58 | #endif | |
59 | ||
845ca893 | 60 | static _Noreturn void |
873fbd0b | 61 | usage (int err) |
2f1de3dd | 62 | { |
ec3b5374 | 63 | fprintf (stdout, "Usage: update-game-score [-m MAX] [-r] [-d DIR] game/scorefile SCORE DATA\n"); |
a5d107f3 RS |
64 | fprintf (stdout, " update-game-score -h\n"); |
65 | fprintf (stdout, " -h\t\tDisplay this help.\n"); | |
66 | fprintf (stdout, " -m MAX\t\tLimit the maximum number of scores to MAX.\n"); | |
67 | fprintf (stdout, " -r\t\tSort the scores in increasing order.\n"); | |
68 | fprintf (stdout, " -d DIR\t\tStore scores in DIR (only if not setuid).\n"); | |
69 | exit (err); | |
2f1de3dd CW |
70 | } |
71 | ||
b23b5a5b PE |
72 | static int lock_file (const char *filename, void **state); |
73 | static int unlock_file (const char *filename, void *state); | |
2f1de3dd CW |
74 | |
75 | struct score_entry | |
76 | { | |
77 | long score; | |
cd553ffb | 78 | char *username; |
2f1de3dd CW |
79 | char *data; |
80 | }; | |
81 | ||
b23b5a5b PE |
82 | static int read_scores (const char *filename, struct score_entry **scores, |
83 | int *count); | |
84 | static int push_score (struct score_entry **scores, int *count, | |
85 | int newscore, char *username, char *newdata); | |
86 | static void sort_scores (struct score_entry *scores, int count, int reverse); | |
87 | static int write_scores (const char *filename, | |
88 | const struct score_entry *scores, int count); | |
cf398788 | 89 | |
845ca893 | 90 | static _Noreturn void |
873fbd0b | 91 | lose (const char *msg) |
cf398788 | 92 | { |
a5d107f3 | 93 | fprintf (stderr, "%s\n", msg); |
65396510 | 94 | exit (EXIT_FAILURE); |
cf398788 | 95 | } |
2f1de3dd | 96 | |
1d28afaf DL |
97 | /* Taken from sysdep.c. */ |
98 | #ifndef HAVE_STRERROR | |
99 | #ifndef WINDOWSNT | |
100 | char * | |
ec3b5374 | 101 | strerror (int errnum) |
1d28afaf DL |
102 | { |
103 | extern char *sys_errlist[]; | |
104 | extern int sys_nerr; | |
105 | ||
106 | if (errnum >= 0 && errnum < sys_nerr) | |
107 | return sys_errlist[errnum]; | |
108 | return (char *) "Unknown error"; | |
109 | } | |
110 | #endif /* not WINDOWSNT */ | |
111 | #endif /* ! HAVE_STRERROR */ | |
112 | ||
845ca893 | 113 | static _Noreturn void |
873fbd0b | 114 | lose_syserr (const char *msg) |
d99fabf0 | 115 | { |
a5d107f3 | 116 | fprintf (stderr, "%s: %s\n", msg, strerror (errno)); |
65396510 | 117 | exit (EXIT_FAILURE); |
d99fabf0 CW |
118 | } |
119 | ||
b23b5a5b | 120 | static char * |
f57e2426 | 121 | get_user_id (void) |
cd553ffb | 122 | { |
a5d107f3 | 123 | struct passwd *buf = getpwuid (getuid ()); |
cd553ffb CW |
124 | if (!buf) |
125 | { | |
0c6d656d PE |
126 | long uid = getuid (); |
127 | char *name = malloc (sizeof uid * CHAR_BIT / 3 + 1); | |
128 | if (name) | |
129 | sprintf (name, "%ld", uid); | |
cd553ffb CW |
130 | return name; |
131 | } | |
132 | return buf->pw_name; | |
133 | } | |
134 | ||
b23b5a5b | 135 | static const char * |
988e88ab | 136 | get_prefix (int running_suid, const char *user_prefix) |
8eec804f | 137 | { |
d99fabf0 | 138 | if (!running_suid && user_prefix == NULL) |
a5d107f3 | 139 | lose ("Not using a shared game directory, and no prefix given."); |
d99fabf0 CW |
140 | if (running_suid) |
141 | { | |
142 | #ifdef HAVE_SHARED_GAME_DIR | |
143 | return HAVE_SHARED_GAME_DIR; | |
144 | #else | |
a5d107f3 | 145 | lose ("This program was compiled without HAVE_SHARED_GAME_DIR,\n and should not be suid."); |
d99fabf0 CW |
146 | #endif |
147 | } | |
148 | return user_prefix; | |
8eec804f CW |
149 | } |
150 | ||
2f1de3dd | 151 | int |
873fbd0b | 152 | main (int argc, char **argv) |
2f1de3dd | 153 | { |
d99fabf0 | 154 | int c, running_suid; |
2f1de3dd | 155 | void *lockstate; |
988e88ab J |
156 | char *user_id, *scorefile; |
157 | const char *prefix, *user_prefix = NULL; | |
2f1de3dd CW |
158 | struct stat buf; |
159 | struct score_entry *scores; | |
8eec804f | 160 | int newscore, scorecount, reverse = 0, max = MAX_SCORES; |
2f1de3dd CW |
161 | char *newdata; |
162 | ||
a5d107f3 | 163 | srand (time (0)); |
2f1de3dd | 164 | |
a5d107f3 | 165 | while ((c = getopt (argc, argv, "hrm:d:")) != -1) |
2f1de3dd CW |
166 | switch (c) |
167 | { | |
168 | case 'h': | |
65396510 | 169 | usage (EXIT_SUCCESS); |
2f1de3dd | 170 | break; |
d99fabf0 CW |
171 | case 'd': |
172 | user_prefix = optarg; | |
173 | break; | |
2f1de3dd CW |
174 | case 'r': |
175 | reverse = 1; | |
176 | break; | |
177 | case 'm': | |
a5d107f3 | 178 | max = atoi (optarg); |
8eec804f CW |
179 | if (max > MAX_SCORES) |
180 | max = MAX_SCORES; | |
2f1de3dd CW |
181 | break; |
182 | default: | |
65396510 | 183 | usage (EXIT_FAILURE); |
2f1de3dd CW |
184 | } |
185 | ||
186 | if (optind+3 != argc) | |
65396510 | 187 | usage (EXIT_FAILURE); |
5795b420 | 188 | |
a5d107f3 | 189 | running_suid = (getuid () != geteuid ()); |
5795b420 | 190 | |
a5d107f3 | 191 | prefix = get_prefix (running_suid, user_prefix); |
8eec804f | 192 | |
a5d107f3 | 193 | scorefile = malloc (strlen (prefix) + strlen (argv[optind]) + 2); |
2f1de3dd | 194 | if (!scorefile) |
a5d107f3 | 195 | lose_syserr ("Couldn't allocate score file"); |
8eec804f | 196 | |
a5d107f3 RS |
197 | strcpy (scorefile, prefix); |
198 | strcat (scorefile, "/"); | |
199 | strcat (scorefile, argv[optind]); | |
200 | newscore = atoi (argv[optind+1]); | |
2f1de3dd | 201 | newdata = argv[optind+2]; |
a5d107f3 | 202 | if (strlen (newdata) > MAX_DATA_LEN) |
8eec804f | 203 | newdata[MAX_DATA_LEN] = '\0'; |
d99fabf0 | 204 | |
00a7e408 RS |
205 | user_id = get_user_id (); |
206 | if (user_id == NULL) | |
a5d107f3 | 207 | lose_syserr ("Couldn't determine user id"); |
177c0ea7 | 208 | |
a5d107f3 RS |
209 | if (stat (scorefile, &buf) < 0) |
210 | lose_syserr ("Failed to access scores file"); | |
177c0ea7 | 211 | |
a5d107f3 RS |
212 | if (lock_file (scorefile, &lockstate) < 0) |
213 | lose_syserr ("Failed to lock scores file"); | |
177c0ea7 | 214 | |
a5d107f3 | 215 | if (read_scores (scorefile, &scores, &scorecount) < 0) |
2f1de3dd | 216 | { |
a5d107f3 RS |
217 | unlock_file (scorefile, lockstate); |
218 | lose_syserr ("Failed to read scores file"); | |
2f1de3dd | 219 | } |
a5d107f3 | 220 | push_score (&scores, &scorecount, newscore, user_id, newdata); |
24e9e996 | 221 | sort_scores (scores, scorecount, reverse); |
8eec804f | 222 | /* Limit the number of scores. If we're using reverse sorting, then |
f0d80d43 PE |
223 | also increment the beginning of the array, to skip over the |
224 | *smallest* scores. Otherwise, just decrementing the number of | |
225 | scores suffices, since the smallest is at the end. */ | |
8eec804f | 226 | if (scorecount > MAX_SCORES) |
f0d80d43 PE |
227 | { |
228 | if (reverse) | |
229 | scores += (scorecount - MAX_SCORES); | |
230 | scorecount = MAX_SCORES; | |
231 | } | |
a5d107f3 | 232 | if (write_scores (scorefile, scores, scorecount) < 0) |
2f1de3dd | 233 | { |
a5d107f3 RS |
234 | unlock_file (scorefile, lockstate); |
235 | lose_syserr ("Failed to write scores file"); | |
2f1de3dd | 236 | } |
a5d107f3 | 237 | unlock_file (scorefile, lockstate); |
65396510 | 238 | exit (EXIT_SUCCESS); |
2f1de3dd CW |
239 | } |
240 | ||
b23b5a5b | 241 | static int |
873fbd0b | 242 | read_score (FILE *f, struct score_entry *score) |
2f1de3dd CW |
243 | { |
244 | int c; | |
a5d107f3 | 245 | if (feof (f)) |
2f1de3dd | 246 | return 1; |
a5d107f3 RS |
247 | while ((c = getc (f)) != EOF |
248 | && isdigit (c)) | |
cd553ffb CW |
249 | { |
250 | score->score *= 10; | |
251 | score->score += (c-48); | |
252 | } | |
a5d107f3 RS |
253 | while ((c = getc (f)) != EOF |
254 | && isspace (c)) | |
cd553ffb CW |
255 | ; |
256 | if (c == EOF) | |
257 | return -1; | |
a5d107f3 | 258 | ungetc (c, f); |
cd553ffb CW |
259 | #ifdef HAVE_GETDELIM |
260 | { | |
7605f1bd | 261 | size_t count = 0; |
a5d107f3 | 262 | if (getdelim (&score->username, &count, ' ', f) < 1 |
cd553ffb CW |
263 | || score->username == NULL) |
264 | return -1; | |
1d4328ff | 265 | /* Trim the space */ |
a5d107f3 | 266 | score->username[strlen (score->username)-1] = '\0'; |
2f1de3dd | 267 | } |
cd553ffb CW |
268 | #else |
269 | { | |
270 | int unameread = 0; | |
271 | int unamelen = 30; | |
a5d107f3 | 272 | char *username = malloc (unamelen); |
f5bceaf8 CW |
273 | if (!username) |
274 | return -1; | |
177c0ea7 | 275 | |
a5d107f3 RS |
276 | while ((c = getc (f)) != EOF |
277 | && !isspace (c)) | |
cd553ffb | 278 | { |
8eec804f | 279 | if (unameread >= unamelen-1) |
a5d107f3 | 280 | if (!(username = realloc (username, unamelen *= 2))) |
8eec804f | 281 | return -1; |
cd553ffb CW |
282 | username[unameread] = c; |
283 | unameread++; | |
284 | } | |
177c0ea7 | 285 | if (c == EOF) |
f5bceaf8 CW |
286 | return -1; |
287 | username[unameread] = '\0'; | |
cd553ffb CW |
288 | score->username = username; |
289 | } | |
290 | #endif | |
2f1de3dd CW |
291 | #ifdef HAVE_GETLINE |
292 | score->data = NULL; | |
7605f1bd | 293 | errno = 0; |
2f1de3dd | 294 | { |
7605f1bd | 295 | size_t len; |
a5d107f3 | 296 | if (getline (&score->data, &len, f) < 0) |
2f1de3dd | 297 | return -1; |
a5d107f3 | 298 | score->data[strlen (score->data)-1] = '\0'; |
2f1de3dd CW |
299 | } |
300 | #else | |
cd553ffb CW |
301 | { |
302 | int cur = 0; | |
303 | int len = 16; | |
a5d107f3 | 304 | char *buf = malloc (len); |
cd553ffb CW |
305 | if (!buf) |
306 | return -1; | |
a5d107f3 | 307 | while ((c = getc (f)) != EOF |
f5bceaf8 | 308 | && c != '\n') |
cd553ffb CW |
309 | { |
310 | if (cur >= len-1) | |
311 | { | |
a5d107f3 | 312 | if (!(buf = realloc (buf, len *= 2))) |
cd553ffb CW |
313 | return -1; |
314 | } | |
315 | buf[cur] = c; | |
316 | cur++; | |
317 | } | |
318 | score->data = buf; | |
5795b420 | 319 | score->data[cur] = '\0'; |
cd553ffb | 320 | } |
2f1de3dd | 321 | #endif |
2f1de3dd CW |
322 | return 0; |
323 | } | |
324 | ||
b23b5a5b | 325 | static int |
873fbd0b | 326 | read_scores (const char *filename, struct score_entry **scores, int *count) |
2f1de3dd CW |
327 | { |
328 | int readval, scorecount, cursize; | |
329 | struct score_entry *ret; | |
a5d107f3 | 330 | FILE *f = fopen (filename, "r"); |
177c0ea7 | 331 | if (!f) |
2f1de3dd CW |
332 | return -1; |
333 | scorecount = 0; | |
334 | cursize = 16; | |
00a7e408 | 335 | ret = (struct score_entry *) malloc (sizeof (struct score_entry) * cursize); |
177c0ea7 | 336 | if (!ret) |
2f1de3dd | 337 | return -1; |
a5d107f3 | 338 | while ((readval = read_score (f, &ret[scorecount])) == 0) |
2f1de3dd | 339 | { |
4c36be58 | 340 | /* We encountered an error. */ |
2f1de3dd CW |
341 | if (readval < 0) |
342 | return -1; | |
343 | scorecount++; | |
344 | if (scorecount >= cursize) | |
345 | { | |
ee435bae JB |
346 | cursize *= 2; |
347 | ret = (struct score_entry *) | |
348 | realloc (ret, (sizeof (struct score_entry) * cursize)); | |
2f1de3dd CW |
349 | if (!ret) |
350 | return -1; | |
351 | } | |
352 | } | |
353 | *count = scorecount; | |
354 | *scores = ret; | |
355 | return 0; | |
356 | } | |
357 | ||
b23b5a5b | 358 | static int |
873fbd0b | 359 | score_compare (const void *a, const void *b) |
2f1de3dd CW |
360 | { |
361 | const struct score_entry *sa = (const struct score_entry *) a; | |
362 | const struct score_entry *sb = (const struct score_entry *) b; | |
363 | return (sb->score > sa->score) - (sb->score < sa->score); | |
364 | } | |
365 | ||
b23b5a5b | 366 | static int |
873fbd0b | 367 | score_compare_reverse (const void *a, const void *b) |
2f1de3dd CW |
368 | { |
369 | const struct score_entry *sa = (const struct score_entry *) a; | |
370 | const struct score_entry *sb = (const struct score_entry *) b; | |
371 | return (sa->score > sb->score) - (sa->score < sb->score); | |
372 | } | |
373 | ||
374 | int | |
873fbd0b | 375 | push_score (struct score_entry **scores, int *count, int newscore, char *username, char *newdata) |
2f1de3dd | 376 | { |
a5d107f3 | 377 | struct score_entry *newscores |
00a7e408 RS |
378 | = (struct score_entry *) realloc (*scores, |
379 | sizeof (struct score_entry) * ((*count) + 1)); | |
2f1de3dd CW |
380 | if (!newscores) |
381 | return -1; | |
382 | newscores[*count].score = newscore; | |
cd553ffb | 383 | newscores[*count].username = username; |
2f1de3dd CW |
384 | newscores[*count].data = newdata; |
385 | (*count) += 1; | |
386 | *scores = newscores; | |
387 | return 0; | |
388 | } | |
177c0ea7 | 389 | |
b23b5a5b | 390 | static void |
873fbd0b | 391 | sort_scores (struct score_entry *scores, int count, int reverse) |
2f1de3dd | 392 | { |
a5d107f3 | 393 | qsort (scores, count, sizeof (struct score_entry), |
2f1de3dd CW |
394 | reverse ? score_compare_reverse : score_compare); |
395 | } | |
396 | ||
b23b5a5b | 397 | static int |
873fbd0b | 398 | write_scores (const char *filename, const struct score_entry *scores, int count) |
2f1de3dd | 399 | { |
177c0ea7 | 400 | FILE *f; |
2f1de3dd | 401 | int i; |
a5d107f3 | 402 | char *tempfile = malloc (strlen (filename) + strlen (".tempXXXXXX") + 1); |
2f1de3dd CW |
403 | if (!tempfile) |
404 | return -1; | |
a5d107f3 RS |
405 | strcpy (tempfile, filename); |
406 | strcat (tempfile, ".tempXXXXXX"); | |
8eec804f | 407 | #ifdef HAVE_MKSTEMP |
a5d107f3 | 408 | if (mkstemp (tempfile) < 0 |
8eec804f | 409 | #else |
a5d107f3 | 410 | if (mktemp (tempfile) != tempfile |
8eec804f | 411 | #endif |
a5d107f3 | 412 | || !(f = fopen (tempfile, "w"))) |
2f1de3dd CW |
413 | return -1; |
414 | for (i = 0; i < count; i++) | |
a5d107f3 | 415 | if (fprintf (f, "%ld %s %s\n", scores[i].score, scores[i].username, |
cd553ffb | 416 | scores[i].data) < 0) |
2f1de3dd | 417 | return -1; |
a5d107f3 RS |
418 | fclose (f); |
419 | if (rename (tempfile, filename) < 0) | |
2f1de3dd | 420 | return -1; |
a5d107f3 | 421 | if (chmod (filename, 0644) < 0) |
2f1de3dd | 422 | return -1; |
8eec804f | 423 | return 0; |
2f1de3dd | 424 | } |
177c0ea7 | 425 | |
b23b5a5b | 426 | static int |
873fbd0b | 427 | lock_file (const char *filename, void **state) |
2f1de3dd CW |
428 | { |
429 | int fd; | |
7c4f6873 | 430 | struct stat buf; |
2f1de3dd | 431 | int attempts = 0; |
988e88ab | 432 | const char *lockext = ".lockfile"; |
a5d107f3 | 433 | char *lockpath = malloc (strlen (filename) + strlen (lockext) + 60); |
2f1de3dd CW |
434 | if (!lockpath) |
435 | return -1; | |
a5d107f3 RS |
436 | strcpy (lockpath, filename); |
437 | strcat (lockpath, lockext); | |
2f1de3dd CW |
438 | *state = lockpath; |
439 | trylock: | |
440 | attempts++; | |
7c4f6873 | 441 | /* If the lock is over an hour old, delete it. */ |
a5d107f3 RS |
442 | if (stat (lockpath, &buf) == 0 |
443 | && (difftime (buf.st_ctime, time (NULL) > 60*60))) | |
444 | unlink (lockpath); | |
00a7e408 RS |
445 | fd = open (lockpath, O_CREAT | O_EXCL, 0600); |
446 | if (fd < 0) | |
2f1de3dd CW |
447 | { |
448 | if (errno == EEXIST) | |
449 | { | |
450 | /* Break the lock; we won't corrupt the file, but we might | |
451 | lose some scores. */ | |
452 | if (attempts > MAX_ATTEMPTS) | |
7c4f6873 | 453 | { |
a5d107f3 | 454 | unlink (lockpath); |
7c4f6873 CW |
455 | attempts = 0; |
456 | } | |
a5d107f3 | 457 | sleep ((rand () % 2)+1); |
2f1de3dd CW |
458 | goto trylock; |
459 | } | |
460 | else | |
461 | return -1; | |
462 | } | |
a5d107f3 | 463 | close (fd); |
2f1de3dd CW |
464 | return 0; |
465 | } | |
177c0ea7 | 466 | |
b23b5a5b | 467 | static int |
873fbd0b | 468 | unlock_file (const char *filename, void *state) |
2f1de3dd CW |
469 | { |
470 | char *lockpath = (char *) state; | |
a5d107f3 | 471 | int ret = unlink (lockpath); |
2f1de3dd | 472 | int saved_errno = errno; |
a5d107f3 | 473 | free (lockpath); |
2f1de3dd CW |
474 | errno = saved_errno; |
475 | return ret; | |
476 | } | |
ab5796a9 | 477 | |
65396510 TTN |
478 | |
479 | /* update-game-score.c ends here */ |