diff --git a/app.js b/app.js
index 7ba58e3..ed8e52f 100644
--- a/app.js
+++ b/app.js
@@ -23,6 +23,7 @@ let fs = require('fs'),
     path = require('path');
 
 global.syzoj = {
+  rootDir: __dirname,
   config: require('./config.json'),
   models: [],
   modules: [],
diff --git a/modules/admin.js b/modules/admin.js
new file mode 100644
index 0000000..5ea56e7
--- /dev/null
+++ b/modules/admin.js
@@ -0,0 +1,347 @@
+/*
+ *  This file is part of SYZOJ.
+ *
+ *  Copyright (c) 2016 Menci <huanghaorui301@gmail.com>
+ *
+ *  SYZOJ is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+ *
+ *  SYZOJ 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 Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public
+ *  License along with SYZOJ. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+let Problem = syzoj.model('problem');
+let JudgeState = syzoj.model('judge_state');
+let Article = syzoj.model('article');
+let Contest = syzoj.model('contest');
+let User = syzoj.model('user');
+let UserPrivilege = syzoj.model('user_privilege');
+
+let db = syzoj.db;
+
+app.get('/admin/info', async (req, res) => {
+  try {
+    if (!res.locals.user || !res.locals.user.is_admin) throw new ErrorMessage('您没有权限进行此操作。');
+
+    let allSubmissionsCount = await JudgeState.count();
+    let todaySubmissionsCount = await JudgeState.count({ submit_time: { $gte: syzoj.utils.getCurrentDate(true) } });
+    let problemsCount = await Problem.count();
+    let articlesCount = await Article.count();
+    let contestsCount = await Contest.count();
+    let usersCount = await User.count();
+
+    res.render('admin_info', {
+      allSubmissionsCount: allSubmissionsCount,
+      todaySubmissionsCount: todaySubmissionsCount,
+      problemsCount: problemsCount,
+      articlesCount: articlesCount,
+      contestsCount: contestsCount,
+      usersCount: usersCount
+    });
+  } catch (e) {
+    syzoj.log(e);
+    res.render('error', {
+      err: e
+    })
+  }
+});
+
+let configItems = {
+  'title': { name: '站点标题', type: String },
+  '邮箱验证': null,
+  'register_mail.enabled': { name: '启用', type: Boolean },
+  'register_mail.address': { name: '发件人地址', type: String },
+  'register_mail.key': { name: '密钥', type: String },
+  '默认参数': null,
+  'default.problem.time_limit': { name: '时间限制（单位：ms）', type: Number },
+  'default.problem.memory_limit': { name: '空间限制（单位：MiB）', type: Number },
+  '限制': null,
+  'limit.time_limit': { name: '最大时间限制（单位：ms）', type: Number },
+  'limit.memory_limit': { name: '最大空间限制（单位：MiB）', type: Number },
+  'limit.data_size': { name: '所有数据包大小（单位：byte）', type: Number },
+  'limit.testdata': { name: '测试数据大小（单位：byte）', type: Number },
+  'limit.submit_code': { name: '代码长度（单位：byte）', type: Number },
+  'limit.submit_answer': { name: '提交答案题目答案大小（单位：byte）', type: Number },
+  'limit.custom_test_input': { name: '自定义测试输入文件大小（单位：byte）', type: Number },
+  'limit.testdata_filecount': { name: '测试数据文件数量（单位：byte）', type: Number },
+  '每页显示数量': null,
+  'page.problem': { name: '题库', type: Number },
+  'page.judge_state': { name: '提交记录', type: Number },
+  'page.problem_statistics': { name: '题目统计', type: Number },
+  'page.ranklist': { name: '排行榜', type: Number },
+  'page.discussion': { name: '讨论', type: Number },
+  'page.article_comment': { name: '评论', type: Number },
+  'page.contest': { name: '比赛', type: Number },
+  '编译器版本': null,
+  'languages.cpp.version': { name: 'C++', type: String },
+  'languages.cpp11.version': { name: 'C++11', type: String },
+  'languages.csharp.version': { name: 'C#', type: String },
+  'languages.c.version': { name: 'C', type: String },
+  'languages.vala.version': { name: 'Vala', type: String },
+  'languages.java.version': { name: 'Java', type: String },
+  'languages.pascal.version': { name: 'Pascal', type: String },
+  'languages.lua.version': { name: 'Lua', type: String },
+  'languages.luajit.version': { name: 'LuaJIT', type: String },
+  'languages.python2.version': { name: 'Python 2', type: String },
+  'languages.python3.version': { name: 'Python 3', type: String },
+  'languages.nodejs.version': { name: 'Node.js', type: String },
+  'languages.ruby.version': { name: 'Ruby', type: String },
+  'languages.haskell.version': { name: 'Haskell', type: String },
+  'languages.ocaml.version': { name: 'OCaml', type: String },
+  'languages.vbnet.version': { name: 'Visual Basic', type: String }
+};
+
+app.get('/admin/config', async (req, res) => {
+  try {
+    if (!res.locals.user || !res.locals.user.is_admin) throw new ErrorMessage('您没有权限进行此操作。');
+
+    for (let i in configItems) {
+      if (!configItems[i]) continue;
+      configItems[i].val = eval(`syzoj.config.${i}`);
+    }
+
+    res.render('admin_config', {
+      items: configItems
+    });
+  } catch (e) {
+    syzoj.log(e);
+    res.render('error', {
+      err: e
+    })
+  }
+});
+
+app.post('/admin/config', async (req, res) => {
+  try {
+    if (!res.locals.user || !res.locals.user.is_admin) throw new ErrorMessage('您没有权限进行此操作。');
+
+    for (let i in configItems) {
+      if (!configItems[i]) continue;
+      if (req.body[i]) {
+        let val;
+        if (configItems[i].type === Boolean) {
+          val = req.body[i] === 'on';
+        } else {
+          val = req.body[i];
+        }
+
+        let f = new Function('val', `syzoj.config.${i} = val`);
+        f(val);
+      }
+    }
+
+    await syzoj.utils.saveConfig();
+
+    res.redirect(syzoj.utils.makeUrl(['admin', 'config']));
+  } catch (e) {
+    syzoj.log(e);
+    res.render('error', {
+      err: e
+    })
+  }
+});
+
+app.get('/admin/privilege', async (req, res) => {
+  try {
+    if (!res.locals.user || !res.locals.user.is_admin) throw new ErrorMessage('您没有权限进行此操作。');
+
+    let a = await UserPrivilege.query();
+    let users = {};
+    for (let p of a) {
+      if (!users[p.user_id]) {
+        users[p.user_id] = {
+          user: await User.fromID(p.user_id),
+          privileges: []
+        };
+      }
+
+      users[p.user_id].privileges.push(p.privilege);
+    }
+
+    res.render('admin_privilege', {
+      users: Object.values(users)
+    });
+  } catch (e) {
+    syzoj.log(e);
+    res.render('error', {
+      err: e
+    })
+  }
+});
+
+app.post('/admin/privilege', async (req, res) => {
+  try {
+    if (!res.locals.user || !res.locals.user.is_admin) throw new ErrorMessage('您没有权限进行此操作。');
+
+    let data = JSON.parse(req.body.data);
+    for (let id in data) {
+      let user = await User.fromID(id);
+      if (!user) throw new ErrorMessage(`不存在 ID 为 ${id} 的用户。`);
+      await user.setPrivileges(data[id]);
+    }
+
+    res.redirect(syzoj.utils.makeUrl(['admin', 'privilege']));
+  } catch (e) {
+    syzoj.log(e);
+    res.render('error', {
+      err: e
+    })
+  }
+});
+
+app.get('/admin/rejudge', async (req, res) => {
+  try {
+    if (!res.locals.user || !res.locals.user.is_admin) throw new ErrorMessage('您没有权限进行此操作。');
+
+    res.render('admin_rejudge', {
+      form: {},
+      count: null
+    });
+  } catch (e) {
+    syzoj.log(e);
+    res.render('error', {
+      err: e
+    })
+  }
+});
+
+app.post('/admin/rejudge', async (req, res) => {
+  try {
+    if (!res.locals.user || !res.locals.user.is_admin) throw new ErrorMessage('您没有权限进行此操作。');
+
+    let user = await User.fromName(req.body.submitter || '');
+    let where = {};
+    if (user) where.user_id = user.id;
+    else if (req.body.submitter) where.user_id = -1;
+
+    let minID = parseInt(req.body.min_id);
+    if (isNaN(minID)) minID = 0;
+    let maxID = parseInt(req.body.max_id);
+    if (isNaN(maxID)) maxID = 2147483647;
+
+    where.id = {
+      $and: {
+        $gte: parseInt(minID),
+        $lte: parseInt(maxID)
+      }
+    };
+
+    let minScore = parseInt(req.body.min_score);
+    if (isNaN(minScore)) minScore = 0;
+    let maxScore = parseInt(req.body.max_score);
+    if (isNaN(maxScore)) maxScore = 100;
+
+    where.score = {
+      $and: {
+        $gte: parseInt(minScore),
+        $lte: parseInt(maxScore)
+      }
+    };
+
+    let minTime = syzoj.utils.parseDate(req.body.min_time);
+    if (isNaN(minTime)) minTime = 0;
+    let maxTime = syzoj.utils.parseDate(req.body.max_time);
+    if (isNaN(maxTime)) maxTime = 2147483647;
+
+    where.submit_time = {
+      $and: {
+        $gte: parseInt(minTime),
+        $lte: parseInt(maxTime)
+      }
+    };
+
+    if (req.body.language) {
+      if (req.body.language === 'submit-answer') where.language = '';
+      else where.language = req.body.language;
+    }
+    if (req.body.status) where.status = { $like: req.body.status + '%' };
+    if (req.body.problem_id) where.problem_id = parseInt(req.body.problem_id) || -1;
+
+    let count = await JudgeState.count(where);
+    if (req.body.type === 'rejudge') {
+      let submissions = await JudgeState.query(null, where);
+      for (let submission of submissions) {
+        await submission.rejudge();
+      }
+    }
+
+    res.render('admin_rejudge', {
+      form: req.body,
+      count: count
+    });
+  } catch (e) {
+    syzoj.log(e);
+    res.render('error', {
+      err: e
+    })
+  }
+});
+
+app.get('/admin/links', async (req, res) => {
+  try {
+    if (!res.locals.user || !res.locals.user.is_admin) throw new ErrorMessage('您没有权限进行此操作。');
+
+    res.render('admin_links', {
+      links: syzoj.config.links || []
+    });
+  } catch (e) {
+    syzoj.log(e);
+    res.render('error', {
+      err: e
+    })
+  }
+});
+
+app.post('/admin/links', async (req, res) => {
+  try {
+    if (!res.locals.user || !res.locals.user.is_admin) throw new ErrorMessage('您没有权限进行此操作。');
+
+    syzoj.config.links = JSON.parse(req.body.data);
+    await syzoj.utils.saveConfig();
+
+    res.redirect(syzoj.utils.makeUrl(['admin', 'links']));
+  } catch (e) {
+    syzoj.log(e);
+    res.render('error', {
+      err: e
+    })
+  }
+});
+
+app.get('/admin/raw', async (req, res) => {
+  try {
+    if (!res.locals.user || !res.locals.user.is_admin) throw new ErrorMessage('您没有权限进行此操作。');
+
+    res.render('admin_raw', {
+      data: JSON.stringify(syzoj.config, null, 2)
+    });
+  } catch (e) {
+    syzoj.log(e);
+    res.render('error', {
+      err: e
+    })
+  }
+});
+
+app.post('/admin/raw', async (req, res) => {
+  try {
+    if (!res.locals.user || !res.locals.user.is_admin) throw new ErrorMessage('您没有权限进行此操作。');
+
+    syzoj.config = JSON.parse(req.body.data);
+    await syzoj.utils.saveConfig();
+
+    res.redirect(syzoj.utils.makeUrl(['admin', 'raw']));
+  } catch (e) {
+    syzoj.log(e);
+    res.render('error', {
+      err: e
+    })
+  }
+});
diff --git a/static/script.js b/static/script.js
index 1aa6db4..ad77f57 100644
--- a/static/script.js
+++ b/static/script.js
@@ -2,8 +2,21 @@ var addUrlParam = function (url, key, val) {
   var newParam = encodeURIComponent(key) + '=' + encodeURIComponent(val);
 
   url = url.split('#')[0];
-  if (url.indexOf('?') === -1) url += '?' + newParam;
-  else url += '&' + newParam;
+  var twoPart = url.split('?'), params = {};
+  var tmp = twoPart[1] ? twoPart[1].split('&') : [];
+  for (let i in tmp) {
+    let a = tmp[i].split('=');
+    params[a[0]] = a[1];
+  }
+
+  params[key] = val;
+
+  url = twoPart[0] + '?';
+  for (let key in params) {
+    url += encodeURIComponent(key) + '=' + encodeURIComponent(params[key]) + '&';
+  }
+
+  url = url.substring(0, url.length - 1);
 
   return url;
 };
diff --git a/utility.js b/utility.js
index baf67ae..2f3384f 100644
--- a/utility.js
+++ b/utility.js
@@ -173,8 +173,15 @@ module.exports = {
   parseDate(s) {
     return parseInt(+new Date(s) / 1000);
   },
-  getCurrentDate() {
-    return parseInt(+new Date / 1000);
+  getCurrentDate(removeTime) {
+    let d = new Date;
+    if (removeTime) {
+      d.setHours(0);
+      d.setMinutes(0);
+      d.setSeconds(0);
+      d.setMilliseconds(0);
+    }
+    return parseInt(+d / 1000);
   },
   makeUrl(req_params, form) {
     let res = '';
@@ -348,5 +355,9 @@ module.exports = {
     } catch (e) {
       return false;
     }
+  },
+  async saveConfig() {
+    let fs = require('fs-extra');
+    fs.writeFileAsync(syzoj.rootDir + '/config.json', JSON.stringify(syzoj.config, null, 2));
   }
 };
diff --git a/views/admin.ejs b/views/admin.ejs
deleted file mode 100644
index d0a60d0..0000000
--- a/views/admin.ejs
+++ /dev/null
@@ -1,25 +0,0 @@
-<% include header %>
-<div class="ui grid">
-  <div class="four wide column">
-    <div class="ui vertical fluid tabular menu">
-      <a class="item">
-        ;
-      </a>
-      <a class="item">
-        Pics
-      </a>
-      <a class="item">
-        Companies
-      </a>
-      <a class="item active">
-        Links
-      </a>
-    </div>
-  </div>
-  <div class="twelve wide stretched column">
-    <div class="ui segment">
-      This is an stretched grid column. This segment will always match the tab height
-    </div>
-  </div>
-</div>
-<% include footer %>
diff --git a/views/admin_config.ejs b/views/admin_config.ejs
new file mode 100644
index 0000000..826538c
--- /dev/null
+++ b/views/admin_config.ejs
@@ -0,0 +1,54 @@
+<% this.adminPage = 'config'; %>
+<% include admin_header %>
+<form method="post" class="ui form">
+<%
+function showTitle(title) {
+  %><h4 class="ui dividing header"><%= title  %></h4><%
+}
+
+function showStringItem(name, text, val) {
+  %>
+  <div class="ui fluid input inline field">
+    <label style="line-height: 37.8px; font-weight: normal; "><%= text %></label>
+    <input type="text" name="<%= name %>" value="<%= val %>">
+  </div>
+  <%
+}
+
+function showNumberItem(name, text, val) {
+  %>
+  <div class="ui fluid input inline field">
+    <label style="line-height: 37.8px; font-weight: normal; "><%= text %></label>
+    <input type="number" name="<%= name %>" value="<%= val %>">
+  </div>
+  <%
+}
+
+function showBooleanItem(name, text, val) {
+  %>
+  <div class="inline field">
+    <div class="ui toggle checkbox">
+      <input name="<%= name %>" type="checkbox" class=""<% if (val) { %> checked<% } %>>
+      <label><%= text %></label>
+    </div>
+  </div>
+  <%
+}
+
+for (let item in items) {
+  if (items[item] === null) {
+    showTitle(item);
+  } else if (items[item].type === String) {
+    showStringItem(item, items[item].name, items[item].val);
+  } else if (items[item].type === Number) {
+    showNumberItem(item, items[item].name, items[item].val);
+  } else {
+    showBooleanItem(item, items[item].name, items[item].val);
+  }
+}
+%>
+<div style="text-align: center; ">
+  <button class="ui blue button">提交</button>
+</div>
+</form>
+<% include admin_footer %>
diff --git a/views/admin_footer.ejs b/views/admin_footer.ejs
new file mode 100644
index 0000000..26e6538
--- /dev/null
+++ b/views/admin_footer.ejs
@@ -0,0 +1,3 @@
+  </div>
+</div>
+<% include footer %>
diff --git a/views/admin_header.ejs b/views/admin_header.ejs
new file mode 100644
index 0000000..ccdd354
--- /dev/null
+++ b/views/admin_header.ejs
@@ -0,0 +1,24 @@
+<%
+let items = {
+  info: '统计信息',
+  config: '系统配置',
+  privilege: '权限管理',
+  rejudge: '一键重测',
+  links: '友链管理',
+  raw: '配置文件'
+};
+%>
+<% this.title = items[this.adminPage] + ' - 后台管理'; %>
+<% include header %>
+<h1 style="text-align: center; margin-bottom: 27px; ">后台管理</h1>
+<div class="ui grid">
+  <div class="three wide column">
+    <div class="ui vertical fluid tabular menu" style="height: 100%; ">
+    <% for (let x in items) { %>
+      <a class="item<% if (this.adminPage === x) { %> active<% } %>"<% if (this.adminPage !== x) { %> href="<%= syzoj.utils.makeUrl(['admin', x]) %>"<% } %>>
+        <%= items[x] %>
+      </a>
+    <% } %>
+    </div>
+  </div>
+  <div class="thirteen wide stretched column">
diff --git a/views/admin_info.ejs b/views/admin_info.ejs
new file mode 100644
index 0000000..3dc90d5
--- /dev/null
+++ b/views/admin_info.ejs
@@ -0,0 +1,79 @@
+<% this.adminPage = 'info'; %>
+<% include admin_header %>
+<style>
+.ui.statistics {
+  width: 100%;
+}
+
+.statistic {
+  width: calc(100% / 3 - 3em);
+}
+
+.statistic .icon {
+  font-size: 0.7em;
+  display: inline-block;
+  vertical-align: top;
+  padding-top: 2px;
+}
+
+.statistic .label {
+  font-weight: normal !important;
+}
+</style>
+<div class="ui statistics">
+  <div class="statistic">
+    <div class="value">
+      <i class="tasks icon"></i>
+      <%= allSubmissionsCount %>
+    </div>
+    <div class="label">
+      总评测量
+    </div>
+  </div>
+  <div class="statistic">
+    <div class="value">
+      <i class="tasks icon"></i>
+      <%= todaySubmissionsCount %>
+    </div>
+    <div class="label">
+      今日评测量
+    </div>
+  </div>
+  <div class="statistic">
+    <div class="value">
+      <i class="list icon"></i>
+      <%= problemsCount %>
+    </div>
+    <div class="label">
+      题目数量
+    </div>
+  </div>
+  <div class="statistic">
+    <div class="value">
+      <i class="comments icon"></i>
+      <%= articlesCount %>
+    </div>
+    <div class="label">
+      讨论数量
+    </div>
+  </div>
+  <div class="statistic">
+    <div class="value">
+      <i class="calendar icon"></i>
+      <%= contestsCount %>
+    </div>
+    <div class="label">
+      比赛数量
+    </div>
+  </div>
+  <div class="statistic">
+    <div class="value">
+      <i class="user icon"></i>
+      <%= usersCount %>
+    </div>
+    <div class="label">
+      用户数量
+    </div>
+  </div>
+</div>
+<% include admin_footer %>
diff --git a/views/admin_links.ejs b/views/admin_links.ejs
new file mode 100644
index 0000000..55f4bae
--- /dev/null
+++ b/views/admin_links.ejs
@@ -0,0 +1,78 @@
+<%
+this.adminPage = 'links';
+%>
+<% include admin_header %>
+<table class="ui center aligned celled table">
+<thead>
+  <tr>
+    <th>名称</th>
+    <th>链接</th>
+    <th width="50px">删除</th>
+  </tr>
+</thead>
+
+<tbody>
+  <% for (let i = 0; i < links.length; i++) { %>
+    <tr>
+      <td><%= links[i].title %></td>
+      <td><a href="<%= links[i].url %>"><%= links[i].url %></a></td>
+      <td>
+        <a onclick="$('#modal-remove-<%= i %>').modal('show');" style="color: #000; " href="#"><i class="remove icon"></i></a>
+        <div class="ui basic modal" id="modal-remove-<%= i %>">
+          <div class="ui icon header">
+            <i class="remove icon"></i>
+            <p style="margin-top: 15px; ">删除友链</p>
+          </div>
+          <div class="content" style="text-align: center; ">
+            <p>确认删除该友链吗？</p>
+          </div>
+          <div class="actions">
+            <div class="ui red basic cancel inverted button">
+              <i class="remove icon"></i>
+              否
+            </div>
+            <a class="ui green ok inverted button remove_link" data-id="<%= i %>">
+              <i class="checkmark icon"></i>
+              是
+            </a>
+          </div>
+        </div>
+      </td>
+    </tr>
+  <% } %>
+</tbody>
+</table>
+
+<div class="ui form">
+  <div class="two fields">
+    <div class="field">
+      <label>名称</label>
+      <input type="text" id="add_title">
+    </div>
+    <div class="field">
+      <label>链接</label>
+      <input type="text" id="add_url">
+    </div>
+  </div>
+  <div style="text-align: center; "><div id="add_button" class="ui submit button">添加</a></div>
+</div>
+
+<form method="post" id="submit_form">
+  <input type="hidden" name="data" id="submit_data">
+</form>
+
+<script>
+var links = <%- JSON.stringify(links) %>;
+$('.remove_link').click(function () {
+  links.splice($(this).data('id'), 1);
+  $('#submit_data').val(JSON.stringify(links));
+  $('#submit_form').submit();
+});
+
+$('#add_button').click(function () {
+  links.push({ title: $('#add_title').val(), url: $('#add_url').val() });
+  $('#submit_data').val(JSON.stringify(links));
+  $('#submit_form').submit();
+});
+</script>
+<% include admin_footer %>
diff --git a/views/admin_privilege.ejs b/views/admin_privilege.ejs
new file mode 100644
index 0000000..e67f27c
--- /dev/null
+++ b/views/admin_privilege.ejs
@@ -0,0 +1,63 @@
+<%
+this.adminPage = 'privilege';
+let privileges = {
+  manage_problem: '管理题目',
+  manage_problem_tag: '管理题目标签',
+  manage_user: '管理用户',
+};
+%>
+<% include admin_header %>
+<table class="ui center aligned celled table">
+<thead>
+  <tr>
+    <th>ID</th>
+    <th>用户名</th>
+    <% for (let privilege in privileges) { %>
+      <th width="20%"><%= privileges[privilege] %></th>
+    <% } %>
+  </tr>
+</thead>
+
+<tbody>
+  <% for (let user of users) { %>
+    <tr>
+      <td><%= user.user.id %></td>
+      <td><%= user.user.username %></td>
+      <% for (let privilege in privileges) { %>
+        <td>
+          <div class="ui fitted toggle checkbox checkbox_privilege" data-user="<%= user.user.id %>" data-name="<%= privilege %>">
+            <input type="checkbox"<% if (user.privileges.includes(privilege)) { %> checked<% } %>>
+            <label></label>
+          </div>
+        </td>
+      <% } %>
+    </tr>
+  <% } %>
+</tbody>
+</table>
+
+<div style="text-align: center; ">
+  <button class="ui button" onclick="submit()">提交</button>
+</div>
+
+<form method="post" id="submit_form">
+  <input type="hidden" name="data" id="submit_data">
+</form>
+
+<script>
+function submit() {
+  var users = {};
+  $('.checkbox_privilege').each(function () {
+    var user = $(this).data('user');
+    var name = $(this).data('name');
+    if (!users[user]) users[user] = [];
+    if ($(this).checkbox('is checked')) {
+      users[user].push(name);
+    }
+  });
+
+  $('#submit_data').val(JSON.stringify(users));
+  $('#submit_form').submit();
+}
+</script>
+<% include admin_footer %>
diff --git a/views/admin_raw.ejs b/views/admin_raw.ejs
new file mode 100644
index 0000000..3a4093f
--- /dev/null
+++ b/views/admin_raw.ejs
@@ -0,0 +1,34 @@
+<% this.adminPage = 'raw'; %>
+<% include admin_header %>
+<form method="post" class="ui form">
+
+<div id="editor" style="border: 1px solid #D4D4D5; height: 500px; margin-bottom: 20px; "><%= data %></div>
+<input type="hidden" name="data">
+
+<script src="/libs/ace/ace.js"></script>
+<script type="text/javascript">
+var editor = ace.edit("editor");
+
+editor.setTheme("ace/theme/tomorrow");
+editor.getSession().setMode("ace/mode/json");
+editor.getSession().setUseSoftTabs(false);
+
+editor.container.name = 'data';
+editor.container.style.lineHeight = 1.6;
+editor.container.style.fontSize = '14px';
+editor.container.style.fontFamily = "'Roboto Mono', 'Bitstream Vera Sans Mono', 'Menlo', 'Consolas', 'Lucida Console', monospace";
+editor.setShowPrintMargin(false);
+editor.renderer.updateFontSize();
+
+var input = $('[name="data"]');
+editor.getSession().on("change", function () {
+  input.val(editor.getSession().getValue());
+});
+</script>
+
+
+<div style="text-align: center; ">
+  <button class="ui blue button">提交</button>
+</div>
+</form>
+<% include admin_footer %>
diff --git a/views/admin_rejudge.ejs b/views/admin_rejudge.ejs
new file mode 100644
index 0000000..2bceb43
--- /dev/null
+++ b/views/admin_rejudge.ejs
@@ -0,0 +1,108 @@
+<% this.adminPage = 'rejudge'; %>
+<% include admin_header %>
+<form method="post" class="ui form">
+
+  <div class="four fields">
+    <div class="field">
+      <label>题目 ID</label>
+      <input type="text" name="problem_id" placeholder="题目 ID" value="<%= form.problem_id %>">
+    </div>
+    <div class="field">
+      <label>用户名</label>
+      <input type="text" name="submitter" placeholder="用户名" value="<%= form.submitter %>">
+    </div>
+    <div class="field">
+      <label>语言</label>
+      <div class="ui selection dropdown">
+        <input type="hidden" name="language" value="<%= form.language %>">
+        <i class="dropdown icon"></i>
+        <div class="default text"></div>
+        <div class="menu">
+          <div class="item" data-value="">不限</div>
+          <div class="item" data-value="submit-answer">提交答案</div>
+          <% for (let lang in syzoj.config.languages) { %>
+            <div class="item" data-value="<%= lang %>"><%= syzoj.config.languages[lang].show %></div>
+          <% } %>
+        </div>
+      </div>
+    </div>
+    <div class="field">
+      <label>状态</label>
+      <div class="ui selection dropdown">
+        <input type="hidden" name="status" value="<%= form.status %>">
+        <i class="dropdown icon"></i>
+        <div class="default text"></div>
+        <div class="menu">
+          <div class="item" data-value="">不限<i class="dropdown icon" style="visibility: hidden; "></i></div>
+          <% for (let status in this.icon) { %>
+            <% if (this.iconHidden.includes(status)) continue; %>
+            <div class="item" data-value="<%= status %>"><span class="status <%= status.toLowerCase().split(' ').join('_') %>"><i class="<%= this.icon[status] %> icon"></i> <%= status %></div>
+          <% } %>
+        </div>
+      </div>
+    </div>
+  </div>
+  <div class="three fields">
+    <div class="field">
+      <label>ID（最小值）</label>
+      <input type="text" name="min_id" placeholder="ID（最小值）" value="<%= form.min_id %>">
+    </div>
+    <div class="field">
+      <label>分数（最小值）</label>
+      <input type="text" name="min_score" placeholder="分数（最小值）" value="<%= form.min_score %>">
+    </div>
+    <div class="field">
+      <label>提交时间（最小值）</label>
+      <input type="text" name="min_time" placeholder="提交时间（最小值）" value="<%= form.min_time || syzoj.utils.formatDate(0) %>">
+    </div>
+  </div>
+  <div class="three fields">
+    <div class="field">
+      <label>ID（最大值）</label>
+      <input type="text" name="max_id" placeholder="ID（最大值）" value="<%= form.max_id %>">
+    </div>
+    <div class="field">
+      <label>分数（最大值）</label>
+      <input type="text" name="max_score" placeholder="分数（最大值）" value="<%= form.max_score %>">
+    </div>
+    <div class="field">
+      <label>提交时间（最大值）</label>
+      <input type="text" name="max_time" placeholder="提交时间（最大值）" value="<%= form.max_time || syzoj.utils.formatDate(2147483647) %>">
+    </div>
+  </div>
+
+  <div style="text-align: center; ">
+    <button class="ui button" name="type" value="query">查询</button>
+    <% if (form.type === 'rejudge') { %>
+      <button class="ui blue disabled button" name="type" value="rejudge">已重测 <%= count %> 条记录</button>
+    <% } else if (count !== null) { %>
+      <a onclick="$('#modal-rejudge').modal('show');" class="ui blue<% if (count === 0) { %> disabled<% } %> button"><% if (count === 0) { %>没有符合条件的记录<% } else { %>重测 <%= count %> 条记录<% } %></a>
+      <button id="submit_rejudge" name="type" value="rejudge" style="display: none; "></button>
+      <div class="ui basic modal" id="modal-rejudge">
+        <div class="ui icon header">
+          <i class="refresh icon"></i>
+          <p style="margin-top: 15px; ">重新评测</p>
+        </div>
+        <div class="content" style="text-align: center; ">
+          <p>确认重新评测 <%= count %> 条记录吗？</p>
+        </div>
+        <div class="actions">
+          <div class="ui red basic cancel inverted button">
+            <i class="remove icon"></i>
+            否
+          </div>
+          <button class="ui green ok inverted button" onclick="$('#submit_rejudge').click()">
+            <i class="checkmark icon"></i>
+            是
+          </button>
+        </div>
+      </div>
+    <% } %>
+  </div>
+</form>
+<script>
+$(function () {
+  $('.ui.dropdown').dropdown();
+});
+</script>
+<% include admin_footer %>
diff --git a/views/header.ejs b/views/header.ejs
index 2ca8ea7..c3210be 100644
--- a/views/header.ejs
+++ b/views/header.ejs
@@ -34,6 +34,9 @@
                 <%= user.username %><% if (user.nameplate) { %><%- user.nameplate %><% } %> <i class="dropdown icon"></i>
                 <div class="menu">
                   <a class="item" href="<%= syzoj.utils.makeUrl(['user', user.id, 'edit']) %>"><i class="edit icon"></i>修改资料</a>
+                  <% if (user.is_admin) { %>
+                    <a class="item" href="<%= syzoj.utils.makeUrl(['admin', 'info']) %>"><i class="settings icon"></i>后台管理</a>
+                  <% } %>
                   <a class="item" href-post="<%= syzoj.utils.makeUrl(['logout'], { url: req.originalUrl }) %>"><i class="power icon"></i>注销</a>
                 </div>
               </div>