【HUSTOJ 判题机源码解读系列03】judge.cc 源码详细注释
【HUSTOJ 判题机源码解读系列03】judge.cc 源码详细注释
本文是 HUSTOJ 中一个比较重要的模块——judge.cc 源代码文件全文注释版本，部分直观的代码不会注释。
做个复习：
- judge.cc 是用来调度判题的
- judge_client.cc 是真正执行判题逻辑的
/*
* Copyright 2008 sempr <iamsempr@gmail.com>
*
* Refacted and modified by zhblue<newsclan@gmail.com>
* Bug report email newsclan@gmail.com
*
* This file is part of HUSTOJ.
*
* HUSTOJ 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 of the License, or
* (at your option) any later version.
*
* HUSTOJ 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 HUSTOJ. if not, see <http://www.gnu.org/licenses/>.
*/
#include <time.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <unistd.h>
#include <syslog.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <signal.h>
#include <sys/resource.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#ifdef OJ_USE_MYSQL
#include <mysql/mysql.h>
#endif
#define BUFFER_SIZE 1024
#define LOCKFILE "/var/run/judged.pid"
#define LOCKMODE (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
#define STD_MB 1048576LL
// 魔术值，定义 OJ 中的各种值
#define OJ_WT0 0
#define OJ_WT1 1
#define OJ_CI 2
#define OJ_RI 3
#define OJ_AC 4
#define OJ_PE 5
#define OJ_WA 6
#define OJ_TL 7
#define OJ_ML 8
#define OJ_OL 9
#define OJ_RE 10
#define OJ_CE 11
#define OJ_CO 12
static char lock_file[BUFFER_SIZE + 32] = LOCKFILE;
static char host_name[BUFFER_SIZE];
static char user_name[BUFFER_SIZE];
static char password[BUFFER_SIZE];
static char db_name[BUFFER_SIZE];
static char oj_home[BUFFER_SIZE];
static char oj_lang_set[BUFFER_SIZE];
static int port_number;
static int max_running; // 并行判题最大数量
static int sleep_time;
static int sleep_tmp;
static int oj_tot;
static int oj_mod;
static int http_judge = 0;
static char http_baseurl[BUFFER_SIZE];
static char http_apipath[BUFFER_SIZE];
static char http_loginpath[BUFFER_SIZE];
static char http_username[BUFFER_SIZE];
static char http_password[BUFFER_SIZE];
static int prefetch = 80; // 预获取的题目数量
static int oj_udp = 0;
static char oj_udpserver[BUFFER_SIZE];
static int oj_udpport = 1536;
static int oj_udp_fd;
static int oj_redis = 0;
static char oj_redisserver[BUFFER_SIZE];
static int oj_redisport;
static char oj_redisauth[BUFFER_SIZE];
static char oj_redisqname[BUFFER_SIZE];
static int turbo_mode = 0;
static int use_docker = 0; // 使用 docker 作为沙箱判题
static char docker_path[BUFFER_SIZE];
static int internal_client = 1;
static int oj_dedicated = 0;
static bool STOP = false;
static int DEBUG = 0;
static int ONCE = 0;
#ifdef _mysql_h
static MYSQL *conn;
static MYSQL_RES *res;
static MYSQL_ROW row;
// static FILE *fp_log;
static char query[BUFFER_SIZE * 4];
#endif
void wait_udp_msg(int fd)
{
char buf[BUFFER_SIZE]; //......1024..
socklen_t len;
int count;
struct sockaddr_in clent_addr; // clent_addr............
memset(buf, 0, BUFFER_SIZE);
len = sizeof(clent_addr);
count = recvfrom(fd, buf, BUFFER_SIZE, 0, (struct sockaddr *)&clent_addr, &len); // recvfrom...............
if (count == -1)
{
printf("recieve data fail!\n");
return;
}
printf("udp client:%s\n", buf);
memset(buf, 0, BUFFER_SIZE);
}
// main 函数接受 SIGQUIT | SIGINT | SIGTERM 信号的处理函数
// signal(SIGQUIT, call_for_exit);
// signal(SIGINT, call_for_exit);
// signal(SIGTERM, call_for_exit);
// 具体操作是屏蔽这些信号终止能够终止进程
// 需要使用 pkill -9 judged 命令强行终止进程
void call_for_exit(int s)
{
if (DEBUG)
{
STOP = true;
printf("Stopping judged...\n");
}
else
{
printf("HUSTOJ Refusing to stop...\n Please use kill -9 !\n");
}
}
// 打印日志的工具函数
void write_log(const char *fmt, ...)
{
va_list ap;
char buffer[4096];
// time_t t = time(NULL);
// int l;
sprintf(buffer, "%s/log/client.log", oj_home);
FILE *fp = fopen(buffer, "ae+");
if (fp == NULL)
{
fprintf(stderr, "openfile error!\n");
system("pwd");
}
va_start(ap, fmt);
vsprintf(buffer, fmt, ap);
fprintf(fp, "%s\n", buffer);
if (DEBUG)
printf("%s\n", buffer);
va_end(ap);
fclose(fp);
}
// 返回字符 = 后面第一个字符的下标
// 例如 after_equal("key=value")
// 012345678
// key=value
// ↑
// 返回 4（指向 'v' 字符）
int after_equal(char *c)
{
int i = 0;
for (; c[i] != '\0' && c[i] != '='; i++)
;
return ++i;
}
// 去除字符串 c 前后的空白字符
// 输入：" hello "
// 返回："hello"
void trim(char *c)
{
char buf[BUFFER_SIZE];
char *start, *end;
strcpy(buf, c);
start = buf;
while (isspace(*start))
start++;
end = start;
while (!isspace(*end))
end++;
*end = '\0';
strcpy(c, start);
}
// 从 buf 中读取 key=value 格式的值，并去除前后空格存入 value
// 例如：
// 调用：read_buf("username = eling", "username", value);
// 执行结果：函数返回 1, value = eling
bool read_buf(char *buf, const char *key, char *value)
{
if (strncmp(buf, key, strlen(key)) == 0)
{
strcpy(value, buf + after_equal(buf));
trim(value);
if (DEBUG)
printf("%s\n", value);
return 1;
}
return 0;
}
// read_int 从 buf 中读取 key=value 格式的整数值，并存入 value 变量
// 例如：
// 调用：read_buf("size = 12", "size", value);
// 执行结果：函数返回 1， value = 12
void read_int(char *buf, const char *key, int *value)
{
char buf2[BUFFER_SIZE];
if (read_buf(buf, key, buf2))
sscanf(buf2, "%d", value);
}
// 读取 /home/judge/src/etc/judge.conf 配置文件
// 然后将这些配置赋值给上面定义的那些全局变量
void init_judge_conf()
{
FILE *fp = NULL;
char buf[BUFFER_SIZE];
host_name[0] = 0;
user_name[0] = 0;
password[0] = 0;
db_name[0] = 0;
port_number = 3306;
max_running = 3;
sleep_time = 1;
oj_tot = 1;
oj_mod = 0;
strcpy(oj_lang_set, "0,1,3,6");
strcpy(oj_udpserver, "127.0.0.1");
strcpy(docker_path, "/usr/bin/docker");
fp = fopen("./etc/judge.conf", "r");
if (fp != NULL)
{
while (fgets(buf, BUFFER_SIZE - 1, fp))
{
read_buf(buf, "OJ_HOST_NAME", host_name);
read_buf(buf, "OJ_USER_NAME", user_name);
read_buf(buf, "OJ_PASSWORD", password);
read_buf(buf, "OJ_DB_NAME", db_name);
read_int(buf, "OJ_PORT_NUMBER", &port_number);
read_int(buf, "OJ_RUNNING", &max_running);
read_int(buf, "OJ_SLEEP_TIME", &sleep_time);
read_int(buf, "OJ_TOTAL", &oj_tot);
read_int(buf, "OJ_DEDICATED", &oj_dedicated);
read_int(buf, "OJ_MOD", &oj_mod);
read_int(buf, "OJ_HTTP_JUDGE", &http_judge);
read_buf(buf, "OJ_HTTP_BASEURL", http_baseurl);
read_buf(buf, "OJ_HTTP_APIPATH", http_apipath);
read_buf(buf, "OJ_HTTP_LOGINPATH", http_loginpath);
read_buf(buf, "OJ_HTTP_USERNAME", http_username);
read_buf(buf, "OJ_HTTP_PASSWORD", http_password);
read_buf(buf, "OJ_LANG_SET", oj_lang_set);
read_int(buf, "OJ_UDP_ENABLE", &oj_udp);
read_buf(buf, "OJ_UDP_SERVER", oj_udpserver);
read_int(buf, "OJ_UDP_PORT", &oj_udpport);
read_int(buf, "OJ_REDISENABLE", &oj_redis);
read_buf(buf, "OJ_REDISSERVER", oj_redisserver);
read_int(buf, "OJ_REDISPORT", &oj_redisport);
read_buf(buf, "OJ_REDISAUTH", oj_redisauth);
read_buf(buf, "OJ_REDISQNAME", oj_redisqname);
read_int(buf, "OJ_TURBO_MODE", &turbo_mode);
read_int(buf, "OJ_USE_DOCKER", &use_docker);
read_int(buf, "OJ_INTERNAL_CLIENT", &internal_client);
read_buf(buf, "OJ_DOCKER_PATH", docker_path);
}
#ifdef _mysql_h
if (oj_tot == 1)
{
sprintf(query,
"SELECT solution_id FROM solution WHERE language in (%s) and result<2 ORDER BY result, solution_id limit %d",
oj_lang_set, prefetch * max_running);
}
else
{
sprintf(query,
"SELECT solution_id FROM solution WHERE language in (%s) and result<2 and MOD(solution_id,%d)=%d ORDER BY result, solution_id ASC limit %d",
oj_lang_set, oj_tot, oj_mod, prefetch * max_running);
}
#endif
sleep_tmp = sleep_time;
fclose(fp);
}
}
// 启动 judge_client 进程判题
void run_client(int runid, int clientid)
{
// 使用 setrlimit 系统调用
// 能够限制进程使用的 CPU、内存、硬盘等计算机的资源
// 有很多条件编译语句，针对不同的平台，做不同的限制
char buf[BUFFER_SIZE], runidstr[BUFFER_SIZE];
struct rlimit LIM;
LIM.rlim_max = 800;
LIM.rlim_cur = 800;
setrlimit(RLIMIT_CPU, &LIM);
LIM.rlim_max = 1024 * STD_MB;
LIM.rlim_cur = 1024 * STD_MB;
setrlimit(RLIMIT_FSIZE, &LIM);
#ifdef __mips__
LIM.rlim_max = STD_MB << 12;
LIM.rlim_cur = STD_MB << 12;
#endif
#ifdef __arm__
LIM.rlim_max = STD_MB << 11;
LIM.rlim_cur = STD_MB << 11;
#endif
#ifdef __aarch64__
LIM.rlim_max = STD_MB << 15;
LIM.rlim_cur = STD_MB << 15;
#endif
#ifdef __i386
LIM.rlim_max = STD_MB << 11;
LIM.rlim_cur = STD_MB << 11;
#endif
#ifdef __x86_64__
LIM.rlim_max = STD_MB << 15;
LIM.rlim_cur = STD_MB << 15;
#endif
setrlimit(RLIMIT_AS, &LIM);
LIM.rlim_cur = LIM.rlim_max = 800 * max_running;
setrlimit(RLIMIT_NPROC, &LIM);
// buf[0]=clientid+'0'; buf[1]=0;
sprintf(runidstr, "%d", runid);
sprintf(buf, "%d", clientid);
// write_log("sid=%s\tclient=%s\toj_home=%s\n",runidstr,buf,oj_home);
// sprintf(err,"%s/run%d/error.out",oj_home,clientid);
// freopen(err,"a+",stderr);
// char * const envp[]={(char * const )"PYTHONIOENCODING=utf-8",
// (char * const )"LANG=zh_CN.UTF-8",
// (char * const )"LANGUAGE=zh_CN.UTF-8",
// (char * const )"LC_ALL=zh_CN.UTF-8",NULL};
// if (!DEBUG)
if (use_docker)
{
char docker_v[BUFFER_SIZE * 3];
sprintf(docker_v, "%s:/home/judge", oj_home);
if (internal_client)
execl(docker_path, docker_path, "container", "run", "--pids-limit", "100", "--rm", "--cap-add", "SYS_PTRACE", "--net=host",
"-v", docker_v, "hustoj", "/usr/bin/judge_client", runidstr, buf, (char *)NULL);
else
execl(docker_path, docker_path, "container", "run", "--pids-limit", "100", "--rm", "--cap-add", "SYS_PTRACE", "--net=host",
"-v", docker_v, "hustoj", "/home/judge/src/core/judge_client/judge_client", runidstr, buf, (char *)NULL);
}
else
{
// 使用 execl 系统调用运行 /usr/bin/judge_client 系统调用
execl("/usr/bin/judge_client", "/usr/bin/judge_client", runidstr, buf,
oj_home, (char *)NULL);
}
// else
// execl("/usr/bin/judge_client", "/usr/bin/judge_client", runidstr, buf,
// oj_home, "debug", (char *) NULL);
if (use_docker)
{
printf("DOCKER IS DOWN!\n");
}
// exit(0);
}
#ifdef _mysql_h
int executesql(const char *sql)
{
if (mysql_real_query(conn, sql, strlen(sql)))
{
if (DEBUG)
write_log("%s", mysql_error(conn));
sleep(2);
conn = NULL;
return 1;
}
else
return 0;
}
#endif
#ifdef _mysql_h
int init_mysql()
{
if (conn == NULL)
{
conn = mysql_init(NULL); // init the database connection
/* connect the database */
const char timeout = 30;
mysql_options(conn, MYSQL_OPT_CONNECT_TIMEOUT, &timeout);
if (!mysql_real_connect(conn, host_name, user_name, password, db_name,
port_number, 0, 0))
{
if (DEBUG)
write_log("%s", mysql_error(conn));
sleep(2);
return 1;
}
else
{
return executesql("set names utf8");
}
}
else
{
return executesql("commit");
}
}
#endif
FILE *read_cmd_output(const char *fmt, ...)
{
char cmd[BUFFER_SIZE * 2];
FILE *ret = NULL;
va_list ap;
va_start(ap, fmt);
vsprintf(cmd, fmt, ap);
va_end(ap);
// if(DEBUG) printf("%s\n",cmd);
ret = popen(cmd, "r");
return ret;
}
int read_int_http(FILE *f)
{
char buf[BUFFER_SIZE];
fgets(buf, BUFFER_SIZE - 1, f);
return atoi(buf);
}
bool check_login()
{
const char *cmd =
"wget --post-data=\"checklogin=1\" --load-cookies=cookie --save-cookies=cookie --keep-session-cookies -q -O - \"%s%s\"";
int ret = 0;
FILE *fjobs = read_cmd_output(cmd, http_baseurl, http_apipath);
ret = read_int_http(fjobs);
pclose(fjobs);
return ret > 0;
}
void login()
{
if (!check_login())
{
char cmd[BUFFER_SIZE * 5];
sprintf(cmd,
"wget --post-data=\"user_id=%s&password=%s\" --load-cookies=cookie --save-cookies=cookie --keep-session-cookies -q -O - \"%s%s\"",
http_username, http_password, http_baseurl, http_loginpath);
system(cmd);
}
}
int _get_jobs_http(int *jobs)
{
login();
int ret = 0;
int i = 0;
char buf[BUFFER_SIZE];
const char *cmd =
"wget --post-data=\"getpending=1&oj_lang_set=%s&max_running=%d\" --load-cookies=cookie --save-cookies=cookie --keep-session-cookies -q -O - \"%s%s\"";
FILE *fjobs = read_cmd_output(cmd, oj_lang_set, max_running, http_baseurl, http_apipath);
while (fscanf(fjobs, "%s", buf) != EOF)
{
// puts(buf);
int sid = atoi(buf);
if (sid > 0)
jobs[i++] = sid;
// i++;
}
pclose(fjobs);
ret = i;
while (i <= max_running * prefetch)
jobs[i++] = 0;
return ret;
}
#ifdef _mysql_h
/**
* 从数据库中获取等待判题的 solution 的 solution_id
* 通过 jobs 将 solution_id 数组传出
* 返回值是获取到的 solution_id 的数量
*/
int _get_jobs_mysql(int *jobs)
{
// jobs 是传入参数
// 总体的逻辑就是从 solution 表中查询 未判题的 solution_id，然后将 solution_id 通过传入参数传出
// 具体的 sql 在下面
// SELECT solution_id FROM solution WHERE language in (%s) and result<2 and MOD(solution_id,%d)=%d ORDER BY result, solution_id ASC limit %d
if (mysql_real_query(conn, query, strlen(query)))
{
if (DEBUG)
write_log("%s", mysql_error(conn));
sleep(2);
return 0;
}
res = mysql_store_result(conn);
int i = 0;
int ret = 0;
while (res != NULL && (row = mysql_fetch_row(res)) != NULL)
{
jobs[i++] = atoi(row[0]);
}
if (res != NULL && !executesql("commit"))
{
mysql_free_result(res); // free the memory
res = NULL;
}
else
i = 0;
ret = i;
while (i <= max_running * prefetch)
jobs[i++] = 0;
return ret;
}
#endif
int _get_jobs_redis(int *jobs)
{
int ret = 0;
const char *cmd = "redis-cli -h %s -p %d -a %s --raw rpop %s";
while (ret <= max_running)
{
FILE *fjobs = read_cmd_output(cmd, oj_redisserver, oj_redisport, oj_redisauth, oj_redisqname);
if (fscanf(fjobs, "%d", &jobs[ret]) == 1)
{
ret++;
pclose(fjobs);
}
else
{
pclose(fjobs);
break;
}
}
int i = ret;
while (i <= max_running * prefetch)
jobs[i++] = 0;
if (DEBUG)
printf("redis return %d jobs", ret);
return ret;
}
int get_jobs(int *jobs)
{
// http_judge 是配置
// 判题机支持 mysql 获取判题任务和 http 获取任务
// 默认是 mysql
if (http_judge)
{
return _get_jobs_http(jobs);
}
else
{
if (oj_redis)
{
return _get_jobs_redis(jobs);
}
else
{
#ifdef _mysql_h
return _get_jobs_mysql(jobs);
#else
return 0;
#endif
}
}
}
#ifdef _mysql_h
bool _check_out_mysql(int solution_id, int result)
{
char sql[BUFFER_SIZE];
sprintf(sql,
"UPDATE solution SET result=%d,time=0,memory=0,judgetime=NOW() WHERE solution_id=%d and result<2 LIMIT 1",
result, solution_id);
if (mysql_real_query(conn, sql, strlen(sql)))
{
syslog(LOG_ERR | LOG_DAEMON, "%s", mysql_error(conn));
return false;
}
else
{
if (conn != NULL && mysql_affected_rows(conn) > 0ul)
return true;
else
return false;
}
}
#endif
bool _check_out_http(int solution_id, int result)
{
login();
const char *cmd =
"wget --post-data=\"checkout=1&sid=%d&result=%d\" --load-cookies=cookie --save-cookies=cookie --keep-session-cookies -q -O - \"%s%s\"";
int ret = 0;
FILE *fjobs = read_cmd_output(cmd, solution_id, result, http_baseurl, http_apipath);
fscanf(fjobs, "%d", &ret);
pclose(fjobs);
return ret;
}
/**
* 更新评测结果
*/
bool check_out(int solution_id, int result)
{
if (oj_redis || oj_tot > 1)
return true;
if (http_judge)
{
return _check_out_http(solution_id, result);
}
else
{
#ifdef _mysql_h
return _check_out_mysql(solution_id, result);
#else
return 0;
#endif
}
}
static int workcnt = 0;
/**
* 从数据库获取任务，并且使用 fork() 创建子进程执行任务
* @return int
*/
int work()
{
// char buf[1024];
static int error = 0; // 出错计数器
int retcnt = 0; // return 值
int i = 0;
static pid_t ID[100]; // 父进程存储自己 fork 出来的子进程 ID 数组
int runid = 0;
// jobs 是一个存储等待判题的 solution ID 的数组。
// 其大小由 `max_running * prefetch + 1` 决定，其中：
// `max_running` 是配置项，表示最大并行判题的数量
// 通过预获取更多的等待判题 solution，可以最大程度减少数据库访问次数，提高判题效率
// 但并非每次从数据库都能获取 `max_running * prefetch + 1` 个等待判题的 solution，
// 因此，jobs 数组的结构可能如下：
// `[1001, 1002, 1003, ..., 1009, 0, 0, 0, ..., 0]`
// 其中，值大于 0 的元素表示 `solution_id`，其余的 0 仅为占位符。
// 这也是后续判题任务派发的 `for` 循环中，使用 `jobs[j] > 0` 作为循环条件的原因。
int jobs[max_running * prefetch + 1];
pid_t tmp_pid = 0;
// 初始化 jobs 数组
for (i = 0; i < max_running * prefetch + 1; i++)
jobs[i] = 0;
// 开始从数据库中获取判题任务
// 如果没有获取任务，work() 函数直接返回 0
if (!get_jobs(jobs)) {
return 0;
}
// 注意：循环条件是 jobs[j] > 9
for (int j = 0; jobs[j] > 0; j++)
{
// runid 就是 solution_id
runid = jobs[j];
// 该 OJ 为了兼容其老版本做的处理，不必理会
if (runid % oj_tot != oj_mod)
continue;
// workcnt 记录当前正在运行的判题任务数量
// 如果当前运行的任务数达到或超过 max_running（最大并行判题数），
// 尝试回收已结束的判题子进程（僵尸进程）。
// 1. 使用 waitpid(-1, NULL, WNOHANG) 尝试回收一个已退出的子进程（并非一定能够回收到，只是尝试）
// 2. 如果找到已退出的进程，在 ID 数组中抹去该进程的记录，并调整计数：
// workcnt--（当前运行任务数减少）
// retcnt++（已完成任务数增加）
// 3. 如果 use_docker 启用，但未能正确回收进程
// 则可能发生错误，error++ 计数；否则，error = 0（避免误判 Docker 服务卡死）
if (workcnt >= max_running)
{
// 回收僵尸进程 // if no more client can running
tmp_pid = waitpid(-1, NULL, WNOHANG); // wait 4 one child exit
if (DEBUG)
printf("try get one tmp_pid=%d\n", tmp_pid);
for (i = 0; i < max_running; i++)
{ // get the client id
if (ID[i] == tmp_pid)
{
workcnt--;
retcnt++;
ID[i] = 0;
// 重点：这的 i 就是空闲的 client_id
break; // got the client id
}
}
if (use_docker && (i == max_running || ID[i] != 0))
error++;
else
error = 0; // check if docker service is hanged up
}
else
{ // have free client
for (i = 0; i < max_running; i++) // find the client id
if (ID[i] == 0)
{
// 和上面一样
// 重点：当前的 i 记录了 空闲的 client_id
// 这个 client_id 就是 /home/judge/src/
// 目录下的 run0, run1, run2 用于运行代码的沙箱的数字
break; // got the client id
}
}
if (i < max_running)
{
// chekout(runid, OJ_CI)
// 任务已经派发
if (workcnt < max_running && check_out(runid, OJ_CI))
{
workcnt++;
ID[i] = fork(); // start to fork
if (ID[i] == 0)
{
// 子进程开始执行 run_client 函数
if (DEBUG)
{
write_log("Judging solution %d", runid);
write_log("<<=sid=%d===clientid=%d==>>\n", runid, i);
}
run_client(runid, i); // if the process is the son, run it
workcnt--;
exit(0);
}
}
else
{
// ID[i] = 0;
if (DEBUG)
{
if (workcnt < max_running)
printf("check out failure ! runid:%d pid:%d \n", i, ID[i]);
else
printf("workcnt:%d max_running:%d ! \n", workcnt, max_running);
}
usleep(5000);
}
}
if (DEBUG)
printf("workcnt:%d max_running:%d ! \n", workcnt, max_running);
if (use_docker && (error >= max_running * prefetch))
{ // reboot docker
if (DEBUG)
printf("---------------------------------------------restarting--------------------------------------\n");
// system("/usr/sbin/service docker restart");
#ifdef _mysql_h
executesql("update solution set result=1 where result >1 and result <4 ");
#endif
sleep(1);
error = 0;
}
}
int NOHANG = 0;
if (oj_dedicated && (rand() % 100 > 20))
NOHANG = WNOHANG; // CPU 占用大约80%左右，不要打满
// 这里开始死循环，等待上面 fork() 出来的子进程退出，然后然后做好判题记录
while ((tmp_pid = waitpid(-1, NULL, NOHANG)) > 0)
{ // if run dedicated judge using WNOHANG
for (i = 0; i < max_running; i++)
{ // get the client id
if (ID[i] == tmp_pid)
{
workcnt--;
retcnt++;
ID[i] = 0;
break; // got the client id
}
}
printf("tmp_pid = %d\n", tmp_pid);
}
if (!http_judge)
{
#ifdef _mysql_h
if (res != NULL)
{
mysql_free_result(res); // free the memory
res = NULL;
}
executesql("commit");
#endif
}
if (DEBUG && retcnt)
write_log("<<%ddone!>>", retcnt);
// free(ID);
// free(jobs);
return retcnt;
}
int lockfile(int fd)
{
struct flock fl;
fl.l_type = F_WRLCK;
fl.l_start = 0;
fl.l_whence = SEEK_SET;
fl.l_len = 0;
return (fcntl(fd, F_SETLK, &fl));
}
int already_running()
{
int fd;
char buf[16];
fd = open(lock_file, O_RDWR | O_CREAT, LOCKMODE);
if (fd < 0)
{
syslog(LOG_ERR | LOG_DAEMON, "can't open %s: %s", LOCKFILE,
strerror(errno));
exit(1);
}
if (lockfile(fd) < 0)
{
if (errno == EACCES || errno == EAGAIN)
{
close(fd);
return 1;
}
syslog(LOG_ERR | LOG_DAEMON, "can't lock %s: %s", LOCKFILE,
strerror(errno));
exit(1);
}
ftruncate(fd, 0);
sprintf(buf, "%d", getpid());
write(fd, buf, strlen(buf) + 1);
return (0);
}
// 启动一个守护进程的常规操作
int daemon_init(void)
{
pid_t pid;
if ((pid = fork()) < 0)
return (-1);
else if (pid != 0)
exit(0); /* parent exit */
/* child continues */
setsid(); /* become session leader */
chdir(oj_home); /* change working directory */
umask(0); /* clear file mode creation mask */
close(0); /* close stdin */
close(1); /* close stdout */
close(2); /* close stderr */
int fd = open("/dev/null", O_RDWR);
dup2(fd, 0);
dup2(fd, 1);
dup2(fd, 2);
if (fd > 2)
{
close(fd);
}
return (0);
}
void turbo_mode2()
{
#ifdef _mysql_h
if (turbo_mode == 2)
{
char sql[BUFFER_SIZE];
sprintf(sql, " CALL `sync_result`();");
if (mysql_real_query(conn, sql, strlen(sql)))
;
}
#endif
}
/**
* TRUBO_MODE = 2 放弃用户表和问题表的数据一致性，以在大型比赛中添加更多的判题机来提高判题速度。
*/
int main(int argc, char **argv)
{
int oj_udp_ret = 0;
DEBUG = (argc > 2);
ONCE = (argc > 3);
if (argc > 1)
strcpy(oj_home, argv[1]);
else
strcpy(oj_home, "/home/judge");
chdir(oj_home); // change the dir
sprintf(lock_file, "%s/etc/judge.pid", oj_home);
if (!DEBUG)
daemon_init();
if (already_running())
{
syslog(LOG_ERR | LOG_DAEMON,
"This daemon program is already running!\n");
printf("%s already has one judged on it!\n", oj_home);
return 1;
}
if (!DEBUG)
system("/sbin/iptables -A OUTPUT -m owner --uid-owner judge -j DROP");
// struct timespec final_sleep;
// final_sleep.tv_sec=0;
// final_sleep.tv_nsec=500000000;
init_judge_conf(); // set the database info
if (oj_udp)
{
oj_udp_fd = socket(AF_INET, SOCK_DGRAM, 0);
if (oj_udp_fd < 0)
printf("udp fd open failed! \n");
struct sockaddr_in ser_addr;
memset(&ser_addr, 0, sizeof(ser_addr));
ser_addr.sin_family = AF_INET;
ser_addr.sin_addr.s_addr = inet_addr(oj_udpserver);
ser_addr.sin_port = htons(oj_udpport);
struct timeval timeOut;
timeOut.tv_sec = sleep_time; //..5s..
timeOut.tv_usec = 0;
if (setsockopt(oj_udp_fd, SOL_SOCKET, SO_RCVTIMEO, &timeOut, sizeof(timeOut)) < 0)
{
printf("time out setting failed\n");
}
oj_udp_ret = bind(oj_udp_fd, (struct sockaddr *)&ser_addr, sizeof(ser_addr));
if (oj_udp_ret < 0)
printf("udp fd open failed! \n");
}
signal(SIGQUIT, call_for_exit);
signal(SIGINT, call_for_exit);
signal(SIGTERM, call_for_exit);
int j = 1;
int n = 0;
while (!STOP)
{ // start to run until call for exit
n = 0;
while (j && (http_judge
#ifdef _mysql_h
|| !init_mysql()
#endif
))
{
// 查看 work
j = work();
n += j;
// 如果启用加速模式 并且
if (turbo_mode == 2 && (n > max_running * 10 || j < max_running))
{
turbo_mode2();
n = 0;
}
if (ONCE && j == 0)
break;
}
turbo_mode2();
if (ONCE && j == 0)
{
break;
}
if (n == 0)
{
printf("workcnt:%d\n", workcnt);
if (oj_udp && oj_udp_ret == 0)
{
if (STOP)
return 1;
wait_udp_msg(oj_udp_fd);
if (DEBUG)
printf("udp job ... \n");
}
else
{
sleep(sleep_time);
if (DEBUG)
printf("sleeping ... %ds \n", sleep_time);
}
}
j = 1;
}
#ifdef _mysql_h
mysql_close(conn);
#endif
return 0;
}
到此处，有关 HUSTOJ 判题机的 judge.cc 文件，也可以说是判题的调度模块就完成解读了，在后续文章中就会开始解读真正用来判题的 judge_cient.cc 运行机制和源代码解析了。