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 | |
b23b5a5b | 51 | static int usage (int err) NO_RETURN; |
68441b90 | 52 | |
2f1de3dd | 53 | #define MAX_ATTEMPTS 5 |
8eec804f CW |
54 | #define MAX_SCORES 200 |
55 | #define MAX_DATA_LEN 1024 | |
5795b420 | 56 | |
1d28afaf DL |
57 | #ifndef HAVE_DIFFTIME |
58 | /* OK on POSIX (time_t is arithmetic type) modulo overflow in subtraction. */ | |
59 | #define difftime(t1, t0) (double)((t1) - (t0)) | |
60 | #endif | |
61 | ||
b23b5a5b | 62 | static int |
873fbd0b | 63 | usage (int err) |
2f1de3dd | 64 | { |
ec3b5374 | 65 | fprintf (stdout, "Usage: update-game-score [-m MAX] [-r] [-d DIR] game/scorefile SCORE DATA\n"); |
a5d107f3 RS |
66 | fprintf (stdout, " update-game-score -h\n"); |
67 | fprintf (stdout, " -h\t\tDisplay this help.\n"); | |
68 | fprintf (stdout, " -m MAX\t\tLimit the maximum number of scores to MAX.\n"); | |
69 | fprintf (stdout, " -r\t\tSort the scores in increasing order.\n"); | |
70 | fprintf (stdout, " -d DIR\t\tStore scores in DIR (only if not setuid).\n"); | |
71 | exit (err); | |
2f1de3dd CW |
72 | } |
73 | ||
b23b5a5b PE |
74 | static int lock_file (const char *filename, void **state); |
75 | static int unlock_file (const char *filename, void *state); | |
2f1de3dd CW |
76 | |
77 | struct score_entry | |
78 | { | |
79 | long score; | |
cd553ffb | 80 | char *username; |
2f1de3dd CW |
81 | char *data; |
82 | }; | |
83 | ||
b23b5a5b PE |
84 | static int read_scores (const char *filename, struct score_entry **scores, |
85 | int *count); | |
86 | static int push_score (struct score_entry **scores, int *count, | |
87 | int newscore, char *username, char *newdata); | |
88 | static void sort_scores (struct score_entry *scores, int count, int reverse); | |
89 | static int write_scores (const char *filename, | |
90 | const struct score_entry *scores, int count); | |
cf398788 | 91 | |
b23b5a5b | 92 | static void lose (const char *msg) NO_RETURN; |
cf398788 | 93 | |
b23b5a5b | 94 | static void |
873fbd0b | 95 | lose (const char *msg) |
cf398788 | 96 | { |
a5d107f3 | 97 | fprintf (stderr, "%s\n", msg); |
65396510 | 98 | exit (EXIT_FAILURE); |
cf398788 | 99 | } |
2f1de3dd | 100 | |
b23b5a5b | 101 | static void lose_syserr (const char *msg) NO_RETURN; |
d99fabf0 | 102 | |
1d28afaf DL |
103 | /* Taken from sysdep.c. */ |
104 | #ifndef HAVE_STRERROR | |
105 | #ifndef WINDOWSNT | |
106 | char * | |
ec3b5374 | 107 | strerror (int errnum) |
1d28afaf DL |
108 | { |
109 | extern char *sys_errlist[]; | |
110 | extern int sys_nerr; | |
111 | ||
112 | if (errnum >= 0 && errnum < sys_nerr) | |
113 | return sys_errlist[errnum]; | |
114 | return (char *) "Unknown error"; | |
115 | } | |
116 | #endif /* not WINDOWSNT */ | |
117 | #endif /* ! HAVE_STRERROR */ | |
118 | ||
b23b5a5b | 119 | static void |
873fbd0b | 120 | lose_syserr (const char *msg) |
d99fabf0 | 121 | { |
a5d107f3 | 122 | fprintf (stderr, "%s: %s\n", msg, strerror (errno)); |
65396510 | 123 | exit (EXIT_FAILURE); |
d99fabf0 CW |
124 | } |
125 | ||
b23b5a5b | 126 | static char * |
f57e2426 | 127 | get_user_id (void) |
cd553ffb | 128 | { |
a5d107f3 | 129 | struct passwd *buf = getpwuid (getuid ()); |
cd553ffb CW |
130 | if (!buf) |
131 | { | |
0c6d656d PE |
132 | long uid = getuid (); |
133 | char *name = malloc (sizeof uid * CHAR_BIT / 3 + 1); | |
134 | if (name) | |
135 | sprintf (name, "%ld", uid); | |
cd553ffb CW |
136 | return name; |
137 | } | |
138 | return buf->pw_name; | |
139 | } | |
140 | ||
b23b5a5b | 141 | static const char * |
988e88ab | 142 | get_prefix (int running_suid, const char *user_prefix) |
8eec804f | 143 | { |
d99fabf0 | 144 | if (!running_suid && user_prefix == NULL) |
a5d107f3 | 145 | lose ("Not using a shared game directory, and no prefix given."); |
d99fabf0 CW |
146 | if (running_suid) |
147 | { | |
148 | #ifdef HAVE_SHARED_GAME_DIR | |
149 | return HAVE_SHARED_GAME_DIR; | |
150 | #else | |
a5d107f3 | 151 | lose ("This program was compiled without HAVE_SHARED_GAME_DIR,\n and should not be suid."); |
d99fabf0 CW |
152 | #endif |
153 | } | |
154 | return user_prefix; | |
8eec804f CW |
155 | } |
156 | ||
2f1de3dd | 157 | int |
873fbd0b | 158 | main (int argc, char **argv) |
2f1de3dd | 159 | { |
d99fabf0 | 160 | int c, running_suid; |
2f1de3dd | 161 | void *lockstate; |
988e88ab J |
162 | char *user_id, *scorefile; |
163 | const char *prefix, *user_prefix = NULL; | |
2f1de3dd CW |
164 | struct stat buf; |
165 | struct score_entry *scores; | |
8eec804f | 166 | int newscore, scorecount, reverse = 0, max = MAX_SCORES; |
2f1de3dd CW |
167 | char *newdata; |
168 | ||
a5d107f3 | 169 | srand (time (0)); |
2f1de3dd | 170 | |
a5d107f3 | 171 | while ((c = getopt (argc, argv, "hrm:d:")) != -1) |
2f1de3dd CW |
172 | switch (c) |
173 | { | |
174 | case 'h': | |
65396510 | 175 | usage (EXIT_SUCCESS); |
2f1de3dd | 176 | break; |
d99fabf0 CW |
177 | case 'd': |
178 | user_prefix = optarg; | |
179 | break; | |
2f1de3dd CW |
180 | case 'r': |
181 | reverse = 1; | |
182 | break; | |
183 | case 'm': | |
a5d107f3 | 184 | max = atoi (optarg); |
8eec804f CW |
185 | if (max > MAX_SCORES) |
186 | max = MAX_SCORES; | |
2f1de3dd CW |
187 | break; |
188 | default: | |
65396510 | 189 | usage (EXIT_FAILURE); |
2f1de3dd CW |
190 | } |
191 | ||
192 | if (optind+3 != argc) | |
65396510 | 193 | usage (EXIT_FAILURE); |
5795b420 | 194 | |
a5d107f3 | 195 | running_suid = (getuid () != geteuid ()); |
5795b420 | 196 | |
a5d107f3 | 197 | prefix = get_prefix (running_suid, user_prefix); |
8eec804f | 198 | |
a5d107f3 | 199 | scorefile = malloc (strlen (prefix) + strlen (argv[optind]) + 2); |
2f1de3dd | 200 | if (!scorefile) |
a5d107f3 | 201 | lose_syserr ("Couldn't allocate score file"); |
8eec804f | 202 | |
a5d107f3 RS |
203 | strcpy (scorefile, prefix); |
204 | strcat (scorefile, "/"); | |
205 | strcat (scorefile, argv[optind]); | |
206 | newscore = atoi (argv[optind+1]); | |
2f1de3dd | 207 | newdata = argv[optind+2]; |
a5d107f3 | 208 | if (strlen (newdata) > MAX_DATA_LEN) |
8eec804f | 209 | newdata[MAX_DATA_LEN] = '\0'; |
d99fabf0 | 210 | |
00a7e408 RS |
211 | user_id = get_user_id (); |
212 | if (user_id == NULL) | |
a5d107f3 | 213 | lose_syserr ("Couldn't determine user id"); |
177c0ea7 | 214 | |
a5d107f3 RS |
215 | if (stat (scorefile, &buf) < 0) |
216 | lose_syserr ("Failed to access scores file"); | |
177c0ea7 | 217 | |
a5d107f3 RS |
218 | if (lock_file (scorefile, &lockstate) < 0) |
219 | lose_syserr ("Failed to lock scores file"); | |
177c0ea7 | 220 | |
a5d107f3 | 221 | if (read_scores (scorefile, &scores, &scorecount) < 0) |
2f1de3dd | 222 | { |
a5d107f3 RS |
223 | unlock_file (scorefile, lockstate); |
224 | lose_syserr ("Failed to read scores file"); | |
2f1de3dd | 225 | } |
a5d107f3 | 226 | push_score (&scores, &scorecount, newscore, user_id, newdata); |
24e9e996 | 227 | sort_scores (scores, scorecount, reverse); |
8eec804f | 228 | /* Limit the number of scores. If we're using reverse sorting, then |
f0d80d43 PE |
229 | also increment the beginning of the array, to skip over the |
230 | *smallest* scores. Otherwise, just decrementing the number of | |
231 | scores suffices, since the smallest is at the end. */ | |
8eec804f | 232 | if (scorecount > MAX_SCORES) |
f0d80d43 PE |
233 | { |
234 | if (reverse) | |
235 | scores += (scorecount - MAX_SCORES); | |
236 | scorecount = MAX_SCORES; | |
237 | } | |
a5d107f3 | 238 | if (write_scores (scorefile, scores, scorecount) < 0) |
2f1de3dd | 239 | { |
a5d107f3 RS |
240 | unlock_file (scorefile, lockstate); |
241 | lose_syserr ("Failed to write scores file"); | |
2f1de3dd | 242 | } |
a5d107f3 | 243 | unlock_file (scorefile, lockstate); |
65396510 | 244 | exit (EXIT_SUCCESS); |
2f1de3dd CW |
245 | } |
246 | ||
b23b5a5b | 247 | static int |
873fbd0b | 248 | read_score (FILE *f, struct score_entry *score) |
2f1de3dd CW |
249 | { |
250 | int c; | |
a5d107f3 | 251 | if (feof (f)) |
2f1de3dd | 252 | return 1; |
a5d107f3 RS |
253 | while ((c = getc (f)) != EOF |
254 | && isdigit (c)) | |
cd553ffb CW |
255 | { |
256 | score->score *= 10; | |
257 | score->score += (c-48); | |
258 | } | |
a5d107f3 RS |
259 | while ((c = getc (f)) != EOF |
260 | && isspace (c)) | |
cd553ffb CW |
261 | ; |
262 | if (c == EOF) | |
263 | return -1; | |
a5d107f3 | 264 | ungetc (c, f); |
cd553ffb CW |
265 | #ifdef HAVE_GETDELIM |
266 | { | |
7605f1bd | 267 | size_t count = 0; |
a5d107f3 | 268 | if (getdelim (&score->username, &count, ' ', f) < 1 |
cd553ffb CW |
269 | || score->username == NULL) |
270 | return -1; | |
1d4328ff | 271 | /* Trim the space */ |
a5d107f3 | 272 | score->username[strlen (score->username)-1] = '\0'; |
2f1de3dd | 273 | } |
cd553ffb CW |
274 | #else |
275 | { | |
276 | int unameread = 0; | |
277 | int unamelen = 30; | |
a5d107f3 | 278 | char *username = malloc (unamelen); |
f5bceaf8 CW |
279 | if (!username) |
280 | return -1; | |
177c0ea7 | 281 | |
a5d107f3 RS |
282 | while ((c = getc (f)) != EOF |
283 | && !isspace (c)) | |
cd553ffb | 284 | { |
8eec804f | 285 | if (unameread >= unamelen-1) |
a5d107f3 | 286 | if (!(username = realloc (username, unamelen *= 2))) |
8eec804f | 287 | return -1; |
cd553ffb CW |
288 | username[unameread] = c; |
289 | unameread++; | |
290 | } | |
177c0ea7 | 291 | if (c == EOF) |
f5bceaf8 CW |
292 | return -1; |
293 | username[unameread] = '\0'; | |
cd553ffb CW |
294 | score->username = username; |
295 | } | |
296 | #endif | |
2f1de3dd CW |
297 | #ifdef HAVE_GETLINE |
298 | score->data = NULL; | |
7605f1bd | 299 | errno = 0; |
2f1de3dd | 300 | { |
7605f1bd | 301 | size_t len; |
a5d107f3 | 302 | if (getline (&score->data, &len, f) < 0) |
2f1de3dd | 303 | return -1; |
a5d107f3 | 304 | score->data[strlen (score->data)-1] = '\0'; |
2f1de3dd CW |
305 | } |
306 | #else | |
cd553ffb CW |
307 | { |
308 | int cur = 0; | |
309 | int len = 16; | |
a5d107f3 | 310 | char *buf = malloc (len); |
cd553ffb CW |
311 | if (!buf) |
312 | return -1; | |
a5d107f3 | 313 | while ((c = getc (f)) != EOF |
f5bceaf8 | 314 | && c != '\n') |
cd553ffb CW |
315 | { |
316 | if (cur >= len-1) | |
317 | { | |
a5d107f3 | 318 | if (!(buf = realloc (buf, len *= 2))) |
cd553ffb CW |
319 | return -1; |
320 | } | |
321 | buf[cur] = c; | |
322 | cur++; | |
323 | } | |
324 | score->data = buf; | |
5795b420 | 325 | score->data[cur] = '\0'; |
cd553ffb | 326 | } |
2f1de3dd | 327 | #endif |
2f1de3dd CW |
328 | return 0; |
329 | } | |
330 | ||
b23b5a5b | 331 | static int |
873fbd0b | 332 | read_scores (const char *filename, struct score_entry **scores, int *count) |
2f1de3dd CW |
333 | { |
334 | int readval, scorecount, cursize; | |
335 | struct score_entry *ret; | |
a5d107f3 | 336 | FILE *f = fopen (filename, "r"); |
177c0ea7 | 337 | if (!f) |
2f1de3dd CW |
338 | return -1; |
339 | scorecount = 0; | |
340 | cursize = 16; | |
00a7e408 | 341 | ret = (struct score_entry *) malloc (sizeof (struct score_entry) * cursize); |
177c0ea7 | 342 | if (!ret) |
2f1de3dd | 343 | return -1; |
a5d107f3 | 344 | while ((readval = read_score (f, &ret[scorecount])) == 0) |
2f1de3dd | 345 | { |
4c36be58 | 346 | /* We encountered an error. */ |
2f1de3dd CW |
347 | if (readval < 0) |
348 | return -1; | |
349 | scorecount++; | |
350 | if (scorecount >= cursize) | |
351 | { | |
ee435bae JB |
352 | cursize *= 2; |
353 | ret = (struct score_entry *) | |
354 | realloc (ret, (sizeof (struct score_entry) * cursize)); | |
2f1de3dd CW |
355 | if (!ret) |
356 | return -1; | |
357 | } | |
358 | } | |
359 | *count = scorecount; | |
360 | *scores = ret; | |
361 | return 0; | |
362 | } | |
363 | ||
b23b5a5b | 364 | static int |
873fbd0b | 365 | score_compare (const void *a, const void *b) |
2f1de3dd CW |
366 | { |
367 | const struct score_entry *sa = (const struct score_entry *) a; | |
368 | const struct score_entry *sb = (const struct score_entry *) b; | |
369 | return (sb->score > sa->score) - (sb->score < sa->score); | |
370 | } | |
371 | ||
b23b5a5b | 372 | static int |
873fbd0b | 373 | score_compare_reverse (const void *a, const void *b) |
2f1de3dd CW |
374 | { |
375 | const struct score_entry *sa = (const struct score_entry *) a; | |
376 | const struct score_entry *sb = (const struct score_entry *) b; | |
377 | return (sa->score > sb->score) - (sa->score < sb->score); | |
378 | } | |
379 | ||
380 | int | |
873fbd0b | 381 | push_score (struct score_entry **scores, int *count, int newscore, char *username, char *newdata) |
2f1de3dd | 382 | { |
a5d107f3 | 383 | struct score_entry *newscores |
00a7e408 RS |
384 | = (struct score_entry *) realloc (*scores, |
385 | sizeof (struct score_entry) * ((*count) + 1)); | |
2f1de3dd CW |
386 | if (!newscores) |
387 | return -1; | |
388 | newscores[*count].score = newscore; | |
cd553ffb | 389 | newscores[*count].username = username; |
2f1de3dd CW |
390 | newscores[*count].data = newdata; |
391 | (*count) += 1; | |
392 | *scores = newscores; | |
393 | return 0; | |
394 | } | |
177c0ea7 | 395 | |
b23b5a5b | 396 | static void |
873fbd0b | 397 | sort_scores (struct score_entry *scores, int count, int reverse) |
2f1de3dd | 398 | { |
a5d107f3 | 399 | qsort (scores, count, sizeof (struct score_entry), |
2f1de3dd CW |
400 | reverse ? score_compare_reverse : score_compare); |
401 | } | |
402 | ||
b23b5a5b | 403 | static int |
873fbd0b | 404 | write_scores (const char *filename, const struct score_entry *scores, int count) |
2f1de3dd | 405 | { |
177c0ea7 | 406 | FILE *f; |
2f1de3dd | 407 | int i; |
a5d107f3 | 408 | char *tempfile = malloc (strlen (filename) + strlen (".tempXXXXXX") + 1); |
2f1de3dd CW |
409 | if (!tempfile) |
410 | return -1; | |
a5d107f3 RS |
411 | strcpy (tempfile, filename); |
412 | strcat (tempfile, ".tempXXXXXX"); | |
8eec804f | 413 | #ifdef HAVE_MKSTEMP |
a5d107f3 | 414 | if (mkstemp (tempfile) < 0 |
8eec804f | 415 | #else |
a5d107f3 | 416 | if (mktemp (tempfile) != tempfile |
8eec804f | 417 | #endif |
a5d107f3 | 418 | || !(f = fopen (tempfile, "w"))) |
2f1de3dd CW |
419 | return -1; |
420 | for (i = 0; i < count; i++) | |
a5d107f3 | 421 | if (fprintf (f, "%ld %s %s\n", scores[i].score, scores[i].username, |
cd553ffb | 422 | scores[i].data) < 0) |
2f1de3dd | 423 | return -1; |
a5d107f3 RS |
424 | fclose (f); |
425 | if (rename (tempfile, filename) < 0) | |
2f1de3dd | 426 | return -1; |
a5d107f3 | 427 | if (chmod (filename, 0644) < 0) |
2f1de3dd | 428 | return -1; |
8eec804f | 429 | return 0; |
2f1de3dd | 430 | } |
177c0ea7 | 431 | |
b23b5a5b | 432 | static int |
873fbd0b | 433 | lock_file (const char *filename, void **state) |
2f1de3dd CW |
434 | { |
435 | int fd; | |
7c4f6873 | 436 | struct stat buf; |
2f1de3dd | 437 | int attempts = 0; |
988e88ab | 438 | const char *lockext = ".lockfile"; |
a5d107f3 | 439 | char *lockpath = malloc (strlen (filename) + strlen (lockext) + 60); |
2f1de3dd CW |
440 | if (!lockpath) |
441 | return -1; | |
a5d107f3 RS |
442 | strcpy (lockpath, filename); |
443 | strcat (lockpath, lockext); | |
2f1de3dd CW |
444 | *state = lockpath; |
445 | trylock: | |
446 | attempts++; | |
7c4f6873 | 447 | /* If the lock is over an hour old, delete it. */ |
a5d107f3 RS |
448 | if (stat (lockpath, &buf) == 0 |
449 | && (difftime (buf.st_ctime, time (NULL) > 60*60))) | |
450 | unlink (lockpath); | |
00a7e408 RS |
451 | fd = open (lockpath, O_CREAT | O_EXCL, 0600); |
452 | if (fd < 0) | |
2f1de3dd CW |
453 | { |
454 | if (errno == EEXIST) | |
455 | { | |
456 | /* Break the lock; we won't corrupt the file, but we might | |
457 | lose some scores. */ | |
458 | if (attempts > MAX_ATTEMPTS) | |
7c4f6873 | 459 | { |
a5d107f3 | 460 | unlink (lockpath); |
7c4f6873 CW |
461 | attempts = 0; |
462 | } | |
a5d107f3 | 463 | sleep ((rand () % 2)+1); |
2f1de3dd CW |
464 | goto trylock; |
465 | } | |
466 | else | |
467 | return -1; | |
468 | } | |
a5d107f3 | 469 | close (fd); |
2f1de3dd CW |
470 | return 0; |
471 | } | |
177c0ea7 | 472 | |
b23b5a5b | 473 | static int |
873fbd0b | 474 | unlock_file (const char *filename, void *state) |
2f1de3dd CW |
475 | { |
476 | char *lockpath = (char *) state; | |
a5d107f3 | 477 | int ret = unlink (lockpath); |
2f1de3dd | 478 | int saved_errno = errno; |
a5d107f3 | 479 | free (lockpath); |
2f1de3dd CW |
480 | errno = saved_errno; |
481 | return ret; | |
482 | } | |
ab5796a9 | 483 | |
65396510 TTN |
484 | |
485 | /* update-game-score.c ends here */ |