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Initial version.
This commit is contained in:
Colin Walters
parent
5162c705f8
commit
2f1de3dd26
373
lib-src/update-game-score.c
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373
lib-src/update-game-score.c
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@ -0,0 +1,373 @@
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/* update-game-score.c --- Update a score file
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Copyright (C) 2002 Free Software Foundation, Inc.
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This file is part of GNU Emacs.
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GNU Emacs is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Emacs is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Emacs; see the file COPYING. If not, write to
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the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* This program is allows a game to securely and atomically update a
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score file. It should be installed setgid, owned by an appropriate
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group like `games'.
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Created 2002/03/22, by Colin Walters <walters@debian.org>
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*/
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#define _GNU_SOURCE
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#include <unistd.h>
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#include <errno.h>
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#include <string.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <time.h>
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#include <ctype.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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// #include "config.h"
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#define MAX_ATTEMPTS 5
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#define SCORE_FILE_PREFIX "/var/games/emacs/"
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int
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usage(int err)
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{
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fprintf(stdout, "Usage: update-game-score [-m MAX ] [ -r ] game/scorefile SCORE DATA\n");
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fprintf(stdout, " update-game-score -h\n");
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fprintf(stdout, " -h\t\tDisplay this help.\n");
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fprintf(stdout, " -m MAX\t\tLimit the maximum number of scores to MAX.\n");
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fprintf(stdout, " -r\t\tSort the scores in increasing order.\n");
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exit(err);
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}
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int
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lock_file(const char *filename, void **state);
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int
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unlock_file(const char *filename, void *state);
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struct score_entry
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{
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long score;
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char *data;
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};
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int
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read_scores(const char *filename, struct score_entry **scores,
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int *count);
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int
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push_score(struct score_entry **scores, int *count,
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int newscore, char *newdata);
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void
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sort_scores(struct score_entry *scores, int count, int reverse);
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int
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write_scores(const char *filename, const struct score_entry *scores,
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int count);
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int
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main(int argc, char **argv)
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{
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int c;
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void *lockstate;
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char *scorefile;
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struct stat buf;
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struct score_entry *scores;
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int newscore, scorecount, reverse = 0, max = -1;
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char *newdata;
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srand(time(0));
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while ((c = getopt(argc, argv, "hrm:")) != -1)
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switch (c)
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{
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case 'h':
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usage(0);
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break;
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case 'r':
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reverse = 1;
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break;
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case 'm':
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max = atoi(optarg);
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break;
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default:
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usage(1);
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}
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if (optind+3 != argc)
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usage(1);
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scorefile = malloc(strlen(SCORE_FILE_PREFIX) + strlen(argv[optind]) + 20);
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if (!scorefile)
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{
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fprintf(stderr, "Couldn't create score file name: %s\n",
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strerror(errno));
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goto fail;
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}
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strcpy(scorefile, SCORE_FILE_PREFIX);
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strcat(scorefile, argv[optind]);
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newscore = atoi(argv[optind+1]);
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newdata = argv[optind+2];
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if (stat(scorefile, &buf) < 0)
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{
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fprintf(stderr, "Failed to access scores file \"%s\": %s\n",
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scorefile, strerror(errno));
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goto fail;
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}
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if (lock_file(scorefile, &lockstate) < 0)
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{
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fprintf(stderr, "Failed to lock scores file \"%s\": %s\n",
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scorefile, strerror(errno));
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goto fail;
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}
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if (read_scores(scorefile, &scores, &scorecount) < 0)
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{
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fprintf(stderr, "Failed to read scores file \"%s\": %s\n",
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scorefile, strerror(errno));
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goto fail_unlock;
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}
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push_score(&scores, &scorecount, newscore, newdata);
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sort_scores(scores, scorecount, reverse);
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if (write_scores(scorefile, scores, scorecount) < 0)
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{
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fprintf(stderr, "Failed to write scores file \"%s\": %s\n",
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scorefile, strerror(errno));
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goto fail_unlock;
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}
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unlock_file(scorefile, lockstate);
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exit(0);
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fail_unlock:
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unlock_file(scorefile, lockstate);
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fail:
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exit(1);
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}
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int
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read_score(FILE *f, struct score_entry *score)
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{
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int c;
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if (feof(f))
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return 1;
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while ((c = getc(f)) != EOF
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&& isdigit(c)) {
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score->score *= 10;
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score->score += (c-48);
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}
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#ifdef HAVE_GETLINE
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score->data = NULL;
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errno = ESUCCES;
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{
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int len;
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if (getline(&score->data, &len, f) < 0)
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return -1;
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}
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#else
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/* We should probably just copy the getline code into here from
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glibc, instead of this halfassed solution. */
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score->data = malloc(122);
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score->data[0] = '\0';
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if (!fgets(score->data, 120, f))
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return -1;
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#endif
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/* Trim the newline */
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score->data[strlen(score->data)-1] = '\0';
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return 0;
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}
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int
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read_scores(const char *filename, struct score_entry **scores,
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int *count)
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{
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int readval, scorecount, cursize;
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struct score_entry *ret;
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FILE *f = fopen(filename, "r");
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if (!f)
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return -1;
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scorecount = 0;
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cursize = 16;
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ret = malloc(sizeof(struct score_entry) * cursize);
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if (!ret)
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return -1;
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while ((readval = read_score(f, &ret[scorecount])) == 0)
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{
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/* We encoutered an error */
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if (readval < 0)
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return -1;
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scorecount++;
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if (scorecount >= cursize)
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{
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ret = realloc(ret, cursize *= 2);
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if (!ret)
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return -1;
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}
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}
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*count = scorecount;
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*scores = ret;
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return 0;
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}
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int
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score_compare(const void *a, const void *b)
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{
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const struct score_entry *sa = (const struct score_entry *) a;
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const struct score_entry *sb = (const struct score_entry *) b;
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return (sb->score > sa->score) - (sb->score < sa->score);
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}
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int
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score_compare_reverse(const void *a, const void *b)
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{
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const struct score_entry *sa = (const struct score_entry *) a;
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const struct score_entry *sb = (const struct score_entry *) b;
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return (sa->score > sb->score) - (sa->score < sb->score);
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}
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int
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push_score(struct score_entry **scores, int *count,
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int newscore, char *newdata)
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{
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struct score_entry *newscores = realloc(*scores,
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sizeof(struct score_entry) * ((*count) + 1));
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if (!newscores)
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return -1;
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newscores[*count].score = newscore;
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newscores[*count].data = newdata;
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(*count) += 1;
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*scores = newscores;
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return 0;
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}
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void
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sort_scores(struct score_entry *scores, int count, int reverse)
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{
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qsort(scores, count, sizeof(struct score_entry),
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reverse ? score_compare_reverse : score_compare);
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}
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int
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write_scores(const char *filename, const struct score_entry *scores,
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int count)
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{
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FILE *f;
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int i;
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char *tempfile = malloc(strlen(filename) + strlen(".tempXXXXXX") + 1);
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if (!tempfile)
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return -1;
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strcpy(tempfile, filename);
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strcat(tempfile, ".tempXXXXXX");
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if (mkstemp(tempfile) < 0
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|| !(f = fopen(tempfile, "w")))
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return -1;
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for (i = 0; i < count; i++)
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if (fprintf(f, "%ld %s\n", scores[i].score, scores[i].data) < 0)
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return -1;
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fclose(f);
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rename(tempfile, filename);
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return 0;
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}
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#if 0
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int
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lock_file(const char *filename, void **state)
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{
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struct flock lock;
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int *istate;
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int fd, attempts = 0, ret = 0;
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lock.l_type = F_WRLCK;
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lock.l_whence = SEEK_SET;
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lock.l_start = 0;
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lock.l_len = 0;
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istate = malloc(sizeof(int));
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if (!istate)
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return -1;
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if ((fd = open(filename, O_RDWR, 0600)) < 0)
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return -1;
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*istate = fd;
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trylock:
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attempts++;
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if ((ret = fcntl(fd, F_GETLK, &lock)) == -1)
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{
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if (ret == EACCES || ret == EAGAIN)
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if (attempts > MAX_ATTEMPTS)
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exit(1);
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else
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{
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sleep((rand() % 3)+1);
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goto trylock;
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}
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else
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ret = 0 ;
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}
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else
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ret = 0;
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*state = istate;
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return ret;
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}
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int
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unlock_file(const char *filename, void *state)
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{
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int fd, ret;
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fd = *((int *) state);
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free(state);
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ret = close(fd);
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return ret;
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}
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#else
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int
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lock_file(const char *filename, void **state)
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{
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int fd;
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int attempts = 0;
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char *lockext = ".lockfile";
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char *lockpath = malloc(strlen(filename) + strlen(lockext) + 60);
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if (!lockpath)
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return -1;
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strcpy(lockpath, filename);
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strcat(lockpath, lockext);
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*state = lockpath;
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trylock:
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attempts++;
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if ((fd = open(lockpath, O_CREAT | O_EXCL, 0600)) < 0)
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{
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if (errno == EEXIST)
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{
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/* Break the lock; we won't corrupt the file, but we might
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lose some scores. */
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if (attempts > MAX_ATTEMPTS)
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unlink(lockpath);
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else
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sleep((rand() % 2)+1);
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goto trylock;
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}
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else
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return -1;
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}
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close(fd);
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return 0;
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}
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int
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unlock_file(const char *filename, void *state)
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{
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char *lockpath = (char *) state;
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int ret = unlink(lockpath);
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int saved_errno = errno;
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free(lockpath);
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errno = saved_errno;
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return ret;
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}
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#endif
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