1 /* update-game-score.c --- Update a score file
3 Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
6 Author: Colin Walters <walters@debian.org>
8 This file is part of GNU Emacs.
10 GNU Emacs is free software: you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation, either version 3 of the License, or
13 (at your option) any later version.
15 GNU Emacs is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
24 /* This program allows a game to securely and atomically update a
25 score file. It should be installed setuid, owned by an appropriate
28 Alternatively, it can be compiled without HAVE_SHARED_GAME_DIR
29 defined, and in that case it will store scores in the user's home
30 directory (it should NOT be setuid).
59 /* Needed for SunOS4, for instance. */
61 extern int optind
, opterr
;
63 int usage (int err
) NO_RETURN
;
65 #define MAX_ATTEMPTS 5
66 #define MAX_SCORES 200
67 #define MAX_DATA_LEN 1024
70 /* OK on POSIX (time_t is arithmetic type) modulo overflow in subtraction. */
71 #define difftime(t1, t0) (double)((t1) - (t0))
77 fprintf (stdout
, "Usage: update-game-score [-m MAX ] [ -r ] game/scorefile SCORE DATA\n");
78 fprintf (stdout
, " update-game-score -h\n");
79 fprintf (stdout
, " -h\t\tDisplay this help.\n");
80 fprintf (stdout
, " -m MAX\t\tLimit the maximum number of scores to MAX.\n");
81 fprintf (stdout
, " -r\t\tSort the scores in increasing order.\n");
82 fprintf (stdout
, " -d DIR\t\tStore scores in DIR (only if not setuid).\n");
86 int lock_file (const char *filename
, void **state
);
87 int unlock_file (const char *filename
, void *state
);
96 int read_scores (const char *filename
, struct score_entry
**scores
,
98 int push_score (struct score_entry
**scores
, int *count
,
99 int newscore
, char *username
, char *newdata
);
100 void sort_scores (struct score_entry
*scores
, int count
, int reverse
);
101 int write_scores (const char *filename
, const struct score_entry
*scores
,
104 void lose (const char *msg
) NO_RETURN
;
107 lose (const char *msg
)
109 fprintf (stderr
, "%s\n", msg
);
113 void lose_syserr (const char *msg
) NO_RETURN
;
115 /* Taken from sysdep.c. */
116 #ifndef HAVE_STRERROR
122 extern char *sys_errlist
[];
125 if (errnum
>= 0 && errnum
< sys_nerr
)
126 return sys_errlist
[errnum
];
127 return (char *) "Unknown error";
129 #endif /* not WINDOWSNT */
130 #endif /* ! HAVE_STRERROR */
133 lose_syserr (const char *msg
)
135 fprintf (stderr
, "%s: %s\n", msg
, strerror (errno
));
143 struct passwd
*buf
= getpwuid (getuid ());
147 int uid
= (int) getuid ();
151 name
= malloc (count
+1);
154 sprintf (name
, "%d", uid
);
161 get_prefix (int running_suid
, char *user_prefix
)
163 if (!running_suid
&& user_prefix
== NULL
)
164 lose ("Not using a shared game directory, and no prefix given.");
167 #ifdef HAVE_SHARED_GAME_DIR
168 return HAVE_SHARED_GAME_DIR
;
170 lose ("This program was compiled without HAVE_SHARED_GAME_DIR,\n and should not be suid.");
177 main (int argc
, char **argv
)
181 char *user_id
, *scorefile
, *prefix
, *user_prefix
= NULL
;
183 struct score_entry
*scores
;
184 int newscore
, scorecount
, reverse
= 0, max
= MAX_SCORES
;
189 while ((c
= getopt (argc
, argv
, "hrm:d:")) != -1)
193 usage (EXIT_SUCCESS
);
196 user_prefix
= optarg
;
203 if (max
> MAX_SCORES
)
207 usage (EXIT_FAILURE
);
210 if (optind
+3 != argc
)
211 usage (EXIT_FAILURE
);
213 running_suid
= (getuid () != geteuid ());
215 prefix
= get_prefix (running_suid
, user_prefix
);
217 scorefile
= malloc (strlen (prefix
) + strlen (argv
[optind
]) + 2);
219 lose_syserr ("Couldn't allocate score file");
221 strcpy (scorefile
, prefix
);
222 strcat (scorefile
, "/");
223 strcat (scorefile
, argv
[optind
]);
224 newscore
= atoi (argv
[optind
+1]);
225 newdata
= argv
[optind
+2];
226 if (strlen (newdata
) > MAX_DATA_LEN
)
227 newdata
[MAX_DATA_LEN
] = '\0';
229 user_id
= get_user_id ();
231 lose_syserr ("Couldn't determine user id");
233 if (stat (scorefile
, &buf
) < 0)
234 lose_syserr ("Failed to access scores file");
236 if (lock_file (scorefile
, &lockstate
) < 0)
237 lose_syserr ("Failed to lock scores file");
239 if (read_scores (scorefile
, &scores
, &scorecount
) < 0)
241 unlock_file (scorefile
, lockstate
);
242 lose_syserr ("Failed to read scores file");
244 push_score (&scores
, &scorecount
, newscore
, user_id
, newdata
);
245 sort_scores (scores
, scorecount
, reverse
);
246 /* Limit the number of scores. If we're using reverse sorting, then
247 we should increment the beginning of the array, to skip over the
248 *smallest* scores. Otherwise, we just decrement the number of
249 scores, since the smallest will be at the end. */
250 if (scorecount
> MAX_SCORES
)
251 scorecount
-= (scorecount
- MAX_SCORES
);
253 scores
+= (scorecount
- MAX_SCORES
);
254 if (write_scores (scorefile
, scores
, scorecount
) < 0)
256 unlock_file (scorefile
, lockstate
);
257 lose_syserr ("Failed to write scores file");
259 unlock_file (scorefile
, lockstate
);
264 read_score (FILE *f
, struct score_entry
*score
)
269 while ((c
= getc (f
)) != EOF
273 score
->score
+= (c
-48);
275 while ((c
= getc (f
)) != EOF
284 if (getdelim (&score
->username
, &count
, ' ', f
) < 1
285 || score
->username
== NULL
)
288 score
->username
[strlen (score
->username
)-1] = '\0';
294 char *username
= malloc (unamelen
);
298 while ((c
= getc (f
)) != EOF
301 if (unameread
>= unamelen
-1)
302 if (!(username
= realloc (username
, unamelen
*= 2)))
304 username
[unameread
] = c
;
309 username
[unameread
] = '\0';
310 score
->username
= username
;
318 if (getline (&score
->data
, &len
, f
) < 0)
320 score
->data
[strlen (score
->data
)-1] = '\0';
326 char *buf
= malloc (len
);
329 while ((c
= getc (f
)) != EOF
334 if (!(buf
= realloc (buf
, len
*= 2)))
341 score
->data
[cur
] = '\0';
348 read_scores (const char *filename
, struct score_entry
**scores
, int *count
)
350 int readval
, scorecount
, cursize
;
351 struct score_entry
*ret
;
352 FILE *f
= fopen (filename
, "r");
357 ret
= (struct score_entry
*) malloc (sizeof (struct score_entry
) * cursize
);
360 while ((readval
= read_score (f
, &ret
[scorecount
])) == 0)
362 /* We encoutered an error */
366 if (scorecount
>= cursize
)
369 ret
= (struct score_entry
*)
370 realloc (ret
, (sizeof (struct score_entry
) * cursize
));
381 score_compare (const void *a
, const void *b
)
383 const struct score_entry
*sa
= (const struct score_entry
*) a
;
384 const struct score_entry
*sb
= (const struct score_entry
*) b
;
385 return (sb
->score
> sa
->score
) - (sb
->score
< sa
->score
);
389 score_compare_reverse (const void *a
, const void *b
)
391 const struct score_entry
*sa
= (const struct score_entry
*) a
;
392 const struct score_entry
*sb
= (const struct score_entry
*) b
;
393 return (sa
->score
> sb
->score
) - (sa
->score
< sb
->score
);
397 push_score (struct score_entry
**scores
, int *count
, int newscore
, char *username
, char *newdata
)
399 struct score_entry
*newscores
400 = (struct score_entry
*) realloc (*scores
,
401 sizeof (struct score_entry
) * ((*count
) + 1));
404 newscores
[*count
].score
= newscore
;
405 newscores
[*count
].username
= username
;
406 newscores
[*count
].data
= newdata
;
413 sort_scores (struct score_entry
*scores
, int count
, int reverse
)
415 qsort (scores
, count
, sizeof (struct score_entry
),
416 reverse
? score_compare_reverse
: score_compare
);
420 write_scores (const char *filename
, const struct score_entry
*scores
, int count
)
424 char *tempfile
= malloc (strlen (filename
) + strlen (".tempXXXXXX") + 1);
427 strcpy (tempfile
, filename
);
428 strcat (tempfile
, ".tempXXXXXX");
430 if (mkstemp (tempfile
) < 0
432 if (mktemp (tempfile
) != tempfile
434 || !(f
= fopen (tempfile
, "w")))
436 for (i
= 0; i
< count
; i
++)
437 if (fprintf (f
, "%ld %s %s\n", scores
[i
].score
, scores
[i
].username
,
441 if (rename (tempfile
, filename
) < 0)
443 if (chmod (filename
, 0644) < 0)
449 lock_file (const char *filename
, void **state
)
454 char *lockext
= ".lockfile";
455 char *lockpath
= malloc (strlen (filename
) + strlen (lockext
) + 60);
458 strcpy (lockpath
, filename
);
459 strcat (lockpath
, lockext
);
463 /* If the lock is over an hour old, delete it. */
464 if (stat (lockpath
, &buf
) == 0
465 && (difftime (buf
.st_ctime
, time (NULL
) > 60*60)))
467 fd
= open (lockpath
, O_CREAT
| O_EXCL
, 0600);
472 /* Break the lock; we won't corrupt the file, but we might
474 if (attempts
> MAX_ATTEMPTS
)
479 sleep ((rand () % 2)+1);
490 unlock_file (const char *filename
, void *state
)
492 char *lockpath
= (char *) state
;
493 int ret
= unlink (lockpath
);
494 int saved_errno
= errno
;
500 /* arch-tag: 2bf5c52e-4beb-463a-954e-c58b9c64736b
501 (do not change this comment) */
503 /* update-game-score.c ends here */