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authorkcwu <kcwu@63ad8ddf-47c3-0310-b6dd-a9e9d9715204>2005-10-06 03:35:25 +0800
committerkcwu <kcwu@63ad8ddf-47c3-0310-b6dd-a9e9d9715204>2005-10-06 03:35:25 +0800
commit483e783649b0cb8341803ced63c0f72acb4a35db (patch)
tree8070bd190c785b8ec2973a96c3bcfc429496e68c /util
parentb3bdc0360ad8d86422e84055c32cfee26d04db9f (diff)
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make the ticket number less preditable.
git-svn-id: http://opensvn.csie.org/pttbbs/trunk/pttbbs@3220 63ad8ddf-47c3-0310-b6dd-a9e9d9715204
Diffstat (limited to 'util')
-rw-r--r--util/openticket.c65
1 files changed, 7 insertions, 58 deletions
diff --git a/util/openticket.c b/util/openticket.c
index f24aaea3..c200510d 100644
--- a/util/openticket.c
+++ b/util/openticket.c
@@ -56,64 +56,13 @@ int main(int argc, char **argv)
fclose(fp);
}
- srandom(33); // 固定一個 seed 但盡量要避免跟別人的seed同
-
- for( n = (now / (60*60*3)) - 62820; n >0; n--) random();
-
-
-/*
- * 正確的random number generator的用法
- * 是用同一個 seed後取 第一個 第二個 地三個.... 數
- * srand() 設完seed後
- * 每呼叫一次rand()就取下一個數
- *
- * 但因為我們沒有記錄上次取到第幾個
- * 所以用每增四小時()就多取一次 => now / (60*60*4) (每五小時開一次獎)
- * (減 61820 是減少 loop 數)
- *
- * 本來是用srand(time(0)) 不是正確的用法
- * 因為開獎時間有規率 所以會被找出規律
- *
- * ~Ptt
- */
-
- bet=random() % 8;
- /* 以上的說法及 code 並沒比 srand(time(0)) 好. 甚至更好預測. */
-
-
- //XXX: resolve_utmp();
- attach_SHM();
- bet = SHM->UTMPnumber % 8;
- /* FIXME 現在完全依 UTMPnumber 取值, 並沒用到 random function.
- * 小站的 UTMPnumber 可視為定值... */
-
-/*
-
- *
- * 若要以rand inplement 整數的亂數 要注意以下 (man page中有)
- *
- * In Numerical Recipes in C: The Art of Scientific Computing
- * (William H. Press, Brian P. Flannery, Saul A. Teukolsky,
- * William T. Vetterling; New York: Cambridge University
- * Press, 1990 (1st ed, p. 207)), the following comments are
- * made:
- * "If you want to generate a random integer between 1
- * and 10, you should always do it by
- *
- * j=1+(int) (10.0*rand()/(RAND_MAX+1.0));
- *
- * and never by anything resembling
- *
- * j=1+((int) (1000000.0*rand()) % 10);
- *
- * (which uses lower-order bits)."
- *
- * Random-number generation is a complex topic. The Numeri-
- * cal Recipes in C book (see reference above) provides an
- * excellent discussion of practical random-number generation
- * issues in Chapter 7 (Random Numbers).
- * ~ Ptt
- */
+ /* 現在開獎號碼並沒用到 random function.
+ * 小站的 UTMPnumber 可視為定值, 且 UTMPnumber 預設一秒才更新一次
+ * 開站一段時間的開獎 pid 應該無法預測.
+ * 若是小站當站開獎前開站, 則有被猜中的可能 */
+ attach_SHM();
+ bet = (SHM->UTMPnumber+getpid()) % 8;
+
money = ticket[bet] ? total * 95 / ticket[bet] : 9999999;