Commit 2f1de3dd authored by Colin Walters's avatar Colin Walters
Browse files

Initial version.

parent 5162c705
/* update-game-score.c --- Update a score file
Copyright (C) 2002 Free Software Foundation, Inc.
This file is part of GNU Emacs.
GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* This program is allows a game to securely and atomically update a
score file. It should be installed setgid, owned by an appropriate
group like `games'.
Created 2002/03/22, by Colin Walters <walters@debian.org>
*/
#define _GNU_SOURCE
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <ctype.h>
#include <fcntl.h>
#include <sys/stat.h>
// #include "config.h"
#define MAX_ATTEMPTS 5
#define SCORE_FILE_PREFIX "/var/games/emacs/"
int
usage(int err)
{
fprintf(stdout, "Usage: update-game-score [-m MAX ] [ -r ] game/scorefile SCORE DATA\n");
fprintf(stdout, " update-game-score -h\n");
fprintf(stdout, " -h\t\tDisplay this help.\n");
fprintf(stdout, " -m MAX\t\tLimit the maximum number of scores to MAX.\n");
fprintf(stdout, " -r\t\tSort the scores in increasing order.\n");
exit(err);
}
int
lock_file(const char *filename, void **state);
int
unlock_file(const char *filename, void *state);
struct score_entry
{
long score;
char *data;
};
int
read_scores(const char *filename, struct score_entry **scores,
int *count);
int
push_score(struct score_entry **scores, int *count,
int newscore, char *newdata);
void
sort_scores(struct score_entry *scores, int count, int reverse);
int
write_scores(const char *filename, const struct score_entry *scores,
int count);
int
main(int argc, char **argv)
{
int c;
void *lockstate;
char *scorefile;
struct stat buf;
struct score_entry *scores;
int newscore, scorecount, reverse = 0, max = -1;
char *newdata;
srand(time(0));
while ((c = getopt(argc, argv, "hrm:")) != -1)
switch (c)
{
case 'h':
usage(0);
break;
case 'r':
reverse = 1;
break;
case 'm':
max = atoi(optarg);
break;
default:
usage(1);
}
if (optind+3 != argc)
usage(1);
scorefile = malloc(strlen(SCORE_FILE_PREFIX) + strlen(argv[optind]) + 20);
if (!scorefile)
{
fprintf(stderr, "Couldn't create score file name: %s\n",
strerror(errno));
goto fail;
}
strcpy(scorefile, SCORE_FILE_PREFIX);
strcat(scorefile, argv[optind]);
newscore = atoi(argv[optind+1]);
newdata = argv[optind+2];
if (stat(scorefile, &buf) < 0)
{
fprintf(stderr, "Failed to access scores file \"%s\": %s\n",
scorefile, strerror(errno));
goto fail;
}
if (lock_file(scorefile, &lockstate) < 0)
{
fprintf(stderr, "Failed to lock scores file \"%s\": %s\n",
scorefile, strerror(errno));
goto fail;
}
if (read_scores(scorefile, &scores, &scorecount) < 0)
{
fprintf(stderr, "Failed to read scores file \"%s\": %s\n",
scorefile, strerror(errno));
goto fail_unlock;
}
push_score(&scores, &scorecount, newscore, newdata);
sort_scores(scores, scorecount, reverse);
if (write_scores(scorefile, scores, scorecount) < 0)
{
fprintf(stderr, "Failed to write scores file \"%s\": %s\n",
scorefile, strerror(errno));
goto fail_unlock;
}
unlock_file(scorefile, lockstate);
exit(0);
fail_unlock:
unlock_file(scorefile, lockstate);
fail:
exit(1);
}
int
read_score(FILE *f, struct score_entry *score)
{
int c;
if (feof(f))
return 1;
while ((c = getc(f)) != EOF
&& isdigit(c)) {
score->score *= 10;
score->score += (c-48);
}
#ifdef HAVE_GETLINE
score->data = NULL;
errno = ESUCCES;
{
int len;
if (getline(&score->data, &len, f) < 0)
return -1;
}
#else
/* We should probably just copy the getline code into here from
glibc, instead of this halfassed solution. */
score->data = malloc(122);
score->data[0] = '\0';
if (!fgets(score->data, 120, f))
return -1;
#endif
/* Trim the newline */
score->data[strlen(score->data)-1] = '\0';
return 0;
}
int
read_scores(const char *filename, struct score_entry **scores,
int *count)
{
int readval, scorecount, cursize;
struct score_entry *ret;
FILE *f = fopen(filename, "r");
if (!f)
return -1;
scorecount = 0;
cursize = 16;
ret = malloc(sizeof(struct score_entry) * cursize);
if (!ret)
return -1;
while ((readval = read_score(f, &ret[scorecount])) == 0)
{
/* We encoutered an error */
if (readval < 0)
return -1;
scorecount++;
if (scorecount >= cursize)
{
ret = realloc(ret, cursize *= 2);
if (!ret)
return -1;
}
}
*count = scorecount;
*scores = ret;
return 0;
}
int
score_compare(const void *a, const void *b)
{
const struct score_entry *sa = (const struct score_entry *) a;
const struct score_entry *sb = (const struct score_entry *) b;
return (sb->score > sa->score) - (sb->score < sa->score);
}
int
score_compare_reverse(const void *a, const void *b)
{
const struct score_entry *sa = (const struct score_entry *) a;
const struct score_entry *sb = (const struct score_entry *) b;
return (sa->score > sb->score) - (sa->score < sb->score);
}
int
push_score(struct score_entry **scores, int *count,
int newscore, char *newdata)
{
struct score_entry *newscores = realloc(*scores,
sizeof(struct score_entry) * ((*count) + 1));
if (!newscores)
return -1;
newscores[*count].score = newscore;
newscores[*count].data = newdata;
(*count) += 1;
*scores = newscores;
return 0;
}
void
sort_scores(struct score_entry *scores, int count, int reverse)
{
qsort(scores, count, sizeof(struct score_entry),
reverse ? score_compare_reverse : score_compare);
}
int
write_scores(const char *filename, const struct score_entry *scores,
int count)
{
FILE *f;
int i;
char *tempfile = malloc(strlen(filename) + strlen(".tempXXXXXX") + 1);
if (!tempfile)
return -1;
strcpy(tempfile, filename);
strcat(tempfile, ".tempXXXXXX");
if (mkstemp(tempfile) < 0
|| !(f = fopen(tempfile, "w")))
return -1;
for (i = 0; i < count; i++)
if (fprintf(f, "%ld %s\n", scores[i].score, scores[i].data) < 0)
return -1;
fclose(f);
rename(tempfile, filename);
return 0;
}
#if 0
int
lock_file(const char *filename, void **state)
{
struct flock lock;
int *istate;
int fd, attempts = 0, ret = 0;
lock.l_type = F_WRLCK;
lock.l_whence = SEEK_SET;
lock.l_start = 0;
lock.l_len = 0;
istate = malloc(sizeof(int));
if (!istate)
return -1;
if ((fd = open(filename, O_RDWR, 0600)) < 0)
return -1;
*istate = fd;
trylock:
attempts++;
if ((ret = fcntl(fd, F_GETLK, &lock)) == -1)
{
if (ret == EACCES || ret == EAGAIN)
if (attempts > MAX_ATTEMPTS)
exit(1);
else
{
sleep((rand() % 3)+1);
goto trylock;
}
else
ret = 0 ;
}
else
ret = 0;
*state = istate;
return ret;
}
int
unlock_file(const char *filename, void *state)
{
int fd, ret;
fd = *((int *) state);
free(state);
ret = close(fd);
return ret;
}
#else
int
lock_file(const char *filename, void **state)
{
int fd;
int attempts = 0;
char *lockext = ".lockfile";
char *lockpath = malloc(strlen(filename) + strlen(lockext) + 60);
if (!lockpath)
return -1;
strcpy(lockpath, filename);
strcat(lockpath, lockext);
*state = lockpath;
trylock:
attempts++;
if ((fd = open(lockpath, O_CREAT | O_EXCL, 0600)) < 0)
{
if (errno == EEXIST)
{
/* Break the lock; we won't corrupt the file, but we might
lose some scores. */
if (attempts > MAX_ATTEMPTS)
unlink(lockpath);
else
sleep((rand() % 2)+1);
goto trylock;
}
else
return -1;
}
close(fd);
return 0;
}
int
unlock_file(const char *filename, void *state)
{
char *lockpath = (char *) state;
int ret = unlink(lockpath);
int saved_errno = errno;
free(lockpath);
errno = saved_errno;
return ret;
}
#endif
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