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我们以调试 go 代码为示例来介绍GDB的使用。源码内容如下：
package main import &#34;fmt&#34; func add(a, b int) int { sum := 0 sum = a &#43; b return sum } func main() { sum := add(10, 20) fmt.Println(sum) } 构建二进制应用：
go build -gcflags=&#34;-N -l&#34; -o test main.go 启动调试 # gdb ./test # 启动调试 gdb --args ./test arg1 arg2 # 指定参数启动调试 进入gdb调试界面之后，执行 run 命令运行程序。若程序已经运行，我们可以 attach 该程序的进程id进行调试:">
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我们以调试 go 代码为示例来介绍GDB的使用。源码内容如下：
package main import &#34;fmt&#34; func add(a, b int) int { sum := 0 sum = a &#43; b return sum } func main() { sum := add(10, 20) fmt.Println(sum) } 构建二进制应用：
go build -gcflags=&#34;-N -l&#34; -o test main.go 启动调试 # gdb ./test # 启动调试 gdb --args ./test arg1 arg2 # 指定参数启动调试 进入gdb调试界面之后，执行 run 命令运行程序。若程序已经运行，我们可以 attach 该程序的进程id进行调试:" />
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<article class="markdown"><h1 id="gdb">
GDB
<a class="anchor" href="#gdb">#</a>
</h1>
<p><strong>GDB</strong>（GNU symbolic Debugger）是Linux系统下的强大的调试工具，可以用来调试ada, c, c++, asm, minimal, d, fortran, objective-c, go, java,pascal 等多种语言。</p>
<p>我们以调试 <code>go</code> 代码为示例来介绍GDB的使用。源码内容如下：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-go" data-lang="go"><span style="display:flex;"><span><span style="color:#f92672">package</span> <span style="color:#a6e22e">main</span>
</span></span><span style="display:flex;"><span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">import</span> <span style="color:#e6db74">&#34;fmt&#34;</span>
</span></span><span style="display:flex;"><span>
</span></span><span style="display:flex;"><span><span style="color:#66d9ef">func</span> <span style="color:#a6e22e">add</span>(<span style="color:#a6e22e">a</span>, <span style="color:#a6e22e">b</span> <span style="color:#66d9ef">int</span>) <span style="color:#66d9ef">int</span> {
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">sum</span> <span style="color:#f92672">:=</span> <span style="color:#ae81ff">0</span>
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">sum</span> = <span style="color:#a6e22e">a</span> <span style="color:#f92672">+</span> <span style="color:#a6e22e">b</span>
</span></span><span style="display:flex;"><span> <span style="color:#66d9ef">return</span> <span style="color:#a6e22e">sum</span>
</span></span><span style="display:flex;"><span>}
</span></span><span style="display:flex;"><span><span style="color:#66d9ef">func</span> <span style="color:#a6e22e">main</span>() {
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">sum</span> <span style="color:#f92672">:=</span> <span style="color:#a6e22e">add</span>(<span style="color:#ae81ff">10</span>, <span style="color:#ae81ff">20</span>)
</span></span><span style="display:flex;"><span> <span style="color:#a6e22e">fmt</span>.<span style="color:#a6e22e">Println</span>(<span style="color:#a6e22e">sum</span>)
</span></span><span style="display:flex;"><span>}
</span></span></code></pre></div><p>构建二进制应用：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span>go build -gcflags<span style="color:#f92672">=</span><span style="color:#e6db74">&#34;-N -l&#34;</span> -o test main.go
</span></span></code></pre></div><h2 id="启动调试">
启动调试
<a class="anchor" href="#%e5%90%af%e5%8a%a8%e8%b0%83%e8%af%95">#</a>
</h2>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span>gdb ./test <span style="color:#75715e"># 启动调试</span>
</span></span><span style="display:flex;"><span>gdb --args ./test arg1 arg2 <span style="color:#75715e"># 指定参数启动调试</span>
</span></span></code></pre></div><p>进入gdb调试界面之后，执行 <code>run</code> 命令运行程序。若程序已经运行，我们可以 <code>attach</code> 该程序的进程id进行调试:</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span>$ gdb
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> attach <span style="color:#ae81ff">1785</span>
</span></span></code></pre></div><p>当执行 <code>attach</code> 命令的时候，GDB首先会在当前工作目录下查找进程的可执行程序，如果没有找到，接着会用源代码文件搜索路径。我们也可以用file命令来加载可执行文件。</p>
<p>或者通过命令设置进程id:</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span>gdb test <span style="color:#ae81ff">1785</span>
</span></span><span style="display:flex;"><span>gdb test --pid <span style="color:#ae81ff">1785</span>
</span></span></code></pre></div><p>若已运行的进程不含调试信息，我们可以使用同样代码编译出一个带调试信息的版本，然后使用 <code>file</code> 和 <code>attach</code> 命令进行运行调试。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span>$ gdb
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> file test
</span></span><span style="display:flex;"><span>Reading symbols from test...done.
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> attach <span style="color:#ae81ff">1785</span>
</span></span></code></pre></div><h3 id="可视化窗口">
可视化窗口
<a class="anchor" href="#%e5%8f%af%e8%a7%86%e5%8c%96%e7%aa%97%e5%8f%a3">#</a>
</h3>
<p>GDB也支持多窗口图形启动运行，一个窗口显示源码信息，一个窗口显示调试信息：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span>gdb test -tui
</span></span></code></pre></div><p>GDB支持在运行过程中使用 <code>Crtl+X+A</code> 组合键进入多窗口图形界面， GDB支持的快捷操作有：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span>Crtl+X+A // 多窗口与单窗口界面切换
</span></span><span style="display:flex;"><span>Ctrl + X + <span style="color:#ae81ff">2</span> // 显示两个窗口
</span></span><span style="display:flex;"><span>Ctrl + X + <span style="color:#ae81ff">1</span> // 显示一个窗口
</span></span></code></pre></div><h2 id="运行程序">
运行程序
<a class="anchor" href="#%e8%bf%90%e8%a1%8c%e7%a8%8b%e5%ba%8f">#</a>
</h2>
<p>通过 <code>run</code> 命令运行程序， <code>run</code> 命令可以简写成 <code>r</code>：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> run
</span></span></code></pre></div><p>除了启动GDB时候，设置程序的命令行参数外，我们也可以在启动GDB后，再指定程序的命令行参数：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> run arg1 arg2
</span></span></code></pre></div><p>或者通过 <code>set</code> 命令设置命令行参数：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> set args arg1 arg2
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> run
</span></span></code></pre></div><p>除了 <code>run</code> 命令外，我们也可以使用 <code>start</code> 命令运行程序。<code>start</code> 命令会在在 <code>main</code> 函数的第一条语句前面停下来。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> start
</span></span></code></pre></div><p><code>start</code> 命令相当于在Go程序的入口函数 <code>main.main</code> (<code>main.main</code> 代表 <code>main</code> 包的 <code>main</code> 函数)处设置断点，然后运行 <code>run</code> 命令：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> b main.main
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> run
</span></span></code></pre></div><h2 id="断点的设置查看删除禁用">
断点的设置、查看、删除、禁用
<a class="anchor" href="#%e6%96%ad%e7%82%b9%e7%9a%84%e8%ae%be%e7%bd%ae%e6%9f%a5%e7%9c%8b%e5%88%a0%e9%99%a4%e7%a6%81%e7%94%a8">#</a>
</h2>
<h3 id="设置断点">
设置断点
<a class="anchor" href="#%e8%ae%be%e7%bd%ae%e6%96%ad%e7%82%b9">#</a>
</h3>
<p>GDB中是通过 <code>break</code> 命令来设置断点(BreakPoint)，<code>break</code> 可以简写成 <code>b</code>。</p>
<ul>
<li>
<p>break function</p>
<p>在指定函数出设置断点，设置断点后程序会在进入指定函数时停住</p>
</li>
<li>
<p><strong>break linenum</strong></p>
<p>在指定行号处设置断点</p>
</li>
<li>
<p>break +offset/-offset</p>
<p>在当前行号的前面或后面的offset行处设置断点。offset为自然数</p>
</li>
<li>
<p>break filename:linenum</p>
<p>在源文件filename的linenum行处设置断点</p>
</li>
<li>
<p>break filename:function</p>
<p>在源文件filename的function函数的入口处设置断点</p>
</li>
<li>
<p><strong>break *address</strong></p>
<p>在程序运行的内存地址处设置断点</p>
</li>
<li>
<p>break</p>
<p>break命令没有参数时，表示在下一条指令处停住。</p>
</li>
<li>
<p>break &hellip; if <!-- raw HTML omitted --></p>
<p>&hellip;可以是上述的参数，condition表示条件，在条件成立时停住。比如在循环境体中，可以设置break if i=100，表示当i为100时停住程序</p>
</li>
</ul>
<h3 id="查看断点">
查看断点
<a class="anchor" href="#%e6%9f%a5%e7%9c%8b%e6%96%ad%e7%82%b9">#</a>
</h3>
<p>我们可以通过 <code>info</code> 命令查看断点：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> info breakpoint <span style="color:#75715e"># 查看所有断点</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> info breakpoint <span style="color:#ae81ff">3</span> <span style="color:#75715e"># 查看3号断点</span>
</span></span></code></pre></div><h3 id="删除断点">
删除断点
<a class="anchor" href="#%e5%88%a0%e9%99%a4%e6%96%ad%e7%82%b9">#</a>
</h3>
<p>删除断点是通过 <code>delete</code> 命令删除的，<code>delete</code> 命令可以简写成 <code>d</code>：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> delete <span style="color:#ae81ff">3</span> <span style="color:#75715e"># 删除3号断点</span>
</span></span></code></pre></div><h3 id="断点启用与禁用">
断点启用与禁用
<a class="anchor" href="#%e6%96%ad%e7%82%b9%e5%90%af%e7%94%a8%e4%b8%8e%e7%a6%81%e7%94%a8">#</a>
</h3>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> disable <span style="color:#ae81ff">3</span> <span style="color:#75715e"># 禁用3号断点</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> enable <span style="color:#ae81ff">3</span> <span style="color:#75715e"># 启用3号断点</span>
</span></span></code></pre></div><h2 id="调试">
调试
<a class="anchor" href="#%e8%b0%83%e8%af%95">#</a>
</h2>
<h3 id="单步执行">
单步执行
<a class="anchor" href="#%e5%8d%95%e6%ad%a5%e6%89%a7%e8%a1%8c">#</a>
</h3>
<p><code>next</code> 用于单步执行，会一行行执行代码，运到函数时候，不会进入到函数内部，跳过该函数，但会执行该函数，即 <code>step over</code>。可以简写成 <code>n</code>。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> next
</span></span></code></pre></div><h3 id="单步进入">
单步进入
<a class="anchor" href="#%e5%8d%95%e6%ad%a5%e8%bf%9b%e5%85%a5">#</a>
</h3>
<p><code>step</code> 用于单步进入执行，跟 <code>next</code> 命令类似，但是遇到函数时候，会进入到函数内部一步步执行，即 <code>step into</code>。可以简写成 <code>s</code>。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> step
</span></span></code></pre></div><p>与 <code>step</code> 相关的命令 <code>stepi</code>，用于每次执行每次执行一条机器指令。可以简写成 <code>si</code>。</p>
<h3 id="继续执行到下一个断点">
继续执行到下一个断点
<a class="anchor" href="#%e7%bb%a7%e7%bb%ad%e6%89%a7%e8%a1%8c%e5%88%b0%e4%b8%8b%e4%b8%80%e4%b8%aa%e6%96%ad%e7%82%b9">#</a>
</h3>
<p><code>continue</code> 命令会继续执行程序，直到再次遇到断点处。可以简写成 <code>c</code>:</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> <span style="color:#66d9ef">continue</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> <span style="color:#66d9ef">continue</span> <span style="color:#ae81ff">3</span> <span style="color:#75715e"># 跳过3个断点</span>
</span></span></code></pre></div><h3 id="继续运行到指定位置">
继续运行到指定位置
<a class="anchor" href="#%e7%bb%a7%e7%bb%ad%e8%bf%90%e8%a1%8c%e5%88%b0%e6%8c%87%e5%ae%9a%e4%bd%8d%e7%bd%ae">#</a>
</h3>
<p><code>until</code> 命令可以帮助我们实现运行到某一行停住，可以简写成 <code>u</code>：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> <span style="color:#66d9ef">until</span> <span style="color:#ae81ff">5</span>
</span></span></code></pre></div><h3 id="跳过执行">
跳过执行
<a class="anchor" href="#%e8%b7%b3%e8%bf%87%e6%89%a7%e8%a1%8c">#</a>
</h3>
<p><code>skip</code> 命令可以在step时跳过一些不想关注的函数或者某个文件的代码:</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> skip <span style="color:#66d9ef">function</span> add <span style="color:#75715e"># step时跳过add函数</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> info skip <span style="color:#75715e"># 查看skip列表</span>
</span></span></code></pre></div><p>其他相关的命令：</p>
<ul>
<li>skip delete [num] 删除skip</li>
<li>skip enable [num] 启动skip</li>
<li>skip disable [num] 关闭skip</li>
</ul>
<p><strong>注意：</strong> 当不带skip号时候，是针对所有skip进行设置。</p>
<h3 id="执行完成当前函数">
执行完成当前函数
<a class="anchor" href="#%e6%89%a7%e8%a1%8c%e5%ae%8c%e6%88%90%e5%bd%93%e5%89%8d%e5%87%bd%e6%95%b0">#</a>
</h3>
<p><code>finish</code> 命令用来将当前函数执行完成，并打印函数返回时的堆栈地址、返回值、参数值等信息，即<code>step out</code> 。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> finish
</span></span></code></pre></div><h2 id="查看源码">
查看源码
<a class="anchor" href="#%e6%9f%a5%e7%9c%8b%e6%ba%90%e7%a0%81">#</a>
</h2>
<p>GDB中的 <code>list</code> 命令用来显示源码信息。<code>list</code> 命令可以简写成 <code>l</code>。</p>
<ul>
<li>
<p><strong>list</strong></p>
<p>从第一行开始显示源码，继续输入list，可列出后面的源码</p>
</li>
<li>
<p><strong>list linenum</strong></p>
<p>列出linenum行附近的源码</p>
</li>
<li>
<p><strong>list function</strong></p>
<p>列出函数function的代码</p>
</li>
<li>
<p>list filename:linenum</p>
<p>列出文件filename文件中，linenum行出的代码</p>
</li>
<li>
<p>list filename:function</p>
<p>列出文件filename中，函数function的代码</p>
</li>
<li>
<p>list +offset/-offset</p>
<p>列出在当前行号的前面或后面的offset行附近的代码。offset为自然数。</p>
</li>
<li>
<p>list +/-</p>
<p>列出当前行后面或者前面的代码</p>
</li>
<li>
<p>list linenum1, linenum2</p>
<p>列出行linenum1和linenum2之间的代码</p>
</li>
</ul>
<h2 id="查看信息">
查看信息
<a class="anchor" href="#%e6%9f%a5%e7%9c%8b%e4%bf%a1%e6%81%af">#</a>
</h2>
<p><code>info</code> 命令用来显示信息，可以简写成 <code>i</code>。</p>
<ul>
<li>
<p><strong>info files</strong></p>
<p>显示当前的调试的文件，包含程序入口地址，内存分段布局位置信息等</p>
</li>
<li>
<p>info breakpoints</p>
<p>显示当前设置的断点列表</p>
</li>
<li>
<p>info registers</p>
<p>显示当前寄存器的值，可以简写成 <code>i r</code>。指定寄存器名称，可以查看具体寄存器信息：<code>i r rsp</code></p>
</li>
<li>
<p>info all-registers</p>
<p>显示所有寄存器的值。GDB提供四个标准寄存器：<code>pc</code> 是程序计数器寄存器，<code>sp</code> 是堆栈指针。<code>fp</code> 用于记录当前堆栈帧的指针，<code>ps</code> 用于记录处理器状态的寄存器。GDB会处理好不同架构系统寄存器不一致问题，比如对于 <code>amd64</code> 架构，<code>pc</code> 对应就是 <code>rip</code> 寄存器。</p>
<p>引用寄存器内容是将寄存器名前置 <code>$</code> 符作为变量来用。比如 <code>$pc</code> 就是程序计数器寄存器值。</p>
</li>
<li>
<p>info args</p>
<p>显示当前函数参数</p>
</li>
<li>
<p>info locals</p>
<p>显示当前局部变量</p>
</li>
<li>
<p><strong>info frame</strong></p>
<p>查看当前栈帧的详细信息，包括 <code>rip</code> 信息，正在运行的指令所在文件位置</p>
</li>
<li>
<p>info variables</p>
<p>查看程序中的变量符号</p>
</li>
<li>
<p>info functions</p>
<p>查看程序中的函数符号</p>
</li>
<li>
<p>info functions regexp</p>
<p>通过正则匹配来查看程序中的函数符号</p>
</li>
<li>
<p>info goroutines</p>
<p>显示当前执行的 <code>goroutine</code> 列表，带 <code>*</code> 的表示当前执行的。注意需要加载 <code>go runtime</code> 支持。</p>
</li>
<li>
<p>info stack</p>
<p>查看栈信息</p>
</li>
<li>
<p>info proc mappings</p>
<p>可以简写成 <code>i proc m</code>。用来查看应用内存映射</p>
</li>
<li>
<p>info proc [procid]</p>
<p>显示进程信息</p>
</li>
<li>
<p>info proc status</p>
<p>显示进程相关信息：包括user id和group id；进程内有多少线程；虚拟内存的使用情况；挂起的信号，阻塞的信号，忽略的信号；TTY；消耗的系统和用户时间；堆栈大小；nice值</p>
</li>
<li>
<p>info display</p>
</li>
<li>
<p>info watchpoints</p>
<p>列出当前所设置了的所有观察点</p>
</li>
<li>
<p>info line [linenum]</p>
<p>查看第 <code>linenum</code> 的代码指令地址信息，不带 <code>linenum</code> 时，显示的是当前位置的指令地址信息</p>
</li>
<li>
<p>info source</p>
<p>显示此源代码的源代码语言</p>
</li>
<li>
<p>info sources</p>
<p>显示程序中所有有调试信息的源文件名，一共显示两个列表：一个是其符号信息已经读过的，一个是还未读取过的</p>
</li>
<li>
<p>info types</p>
<p>显示程序中所有类型符号</p>
</li>
<li>
<p>info types regexp</p>
<p>通过正则匹配来查看程序中的类型符号</p>
</li>
</ul>
<p>其他类似命令有：</p>
<ul>
<li>
<p>show args</p>
<p>查看命令行参数</p>
</li>
<li>
<p>show environment [envname]</p>
<p>查看环境变量信息</p>
</li>
<li>
<p>show paths</p>
<p>查看程序的运行路径</p>
</li>
<li>
<p>whatis var1</p>
<p>显示变量var1类型</p>
</li>
<li>
<p>ptype var1</p>
<p>显示变量 <code>var1</code> 类型，若是 <code>var1</code> 结构体类型，会显示该结构体定义信息。</p>
</li>
</ul>
<h2 id="查看调用栈">
查看调用栈
<a class="anchor" href="#%e6%9f%a5%e7%9c%8b%e8%b0%83%e7%94%a8%e6%a0%88">#</a>
</h2>
<p>通过 <code>where</code> 可以查看调用栈信息：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> where
</span></span><span style="display:flex;"><span><span style="color:#75715e">#0 _rt0_amd64 ()</span>
</span></span><span style="display:flex;"><span> at /usr/lib/go/src/runtime/asm_amd64.s:15
</span></span><span style="display:flex;"><span><span style="color:#75715e">#1 0x0000000000000001 in ?? ()</span>
</span></span><span style="display:flex;"><span><span style="color:#75715e">#2 0x00007fffffffdd2c in ?? ()</span>
</span></span><span style="display:flex;"><span><span style="color:#75715e">#3 0x0000000000000000 in ?? ()</span>
</span></span></code></pre></div><h2 id="设置观察点">
设置观察点
<a class="anchor" href="#%e8%ae%be%e7%bd%ae%e8%a7%82%e5%af%9f%e7%82%b9">#</a>
</h2>
<p>通过 <code>watch</code> 命令，可以设置观察点。当观察点的变量发生变化时，程序会停下来。可以简写成 <code>wa</code></p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> watch sum
</span></span></code></pre></div><h2 id="查看汇编代码">
查看汇编代码
<a class="anchor" href="#%e6%9f%a5%e7%9c%8b%e6%b1%87%e7%bc%96%e4%bb%a3%e7%a0%81">#</a>
</h2>
<p>我们可以通过开启 <code>disassemble-next-line</code> 自动显示汇编代码。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> set disassemble-next-line on
</span></span></code></pre></div><p>当面我们可以查看指定函数的汇编代码：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> disassemble main.main
</span></span></code></pre></div><p><code>disassemble</code> 可以简写成 <code>disas</code>。我们也可以将源代码和汇编代码一一映射起来后进行查看</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> disas /m main.main
</span></span></code></pre></div><p>GDB默认显示汇编指令格式是 <code>AT&amp;T</code> 格式，我们可以改成 <code>intel</code> 格式：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> set disassembly-flavor intel
</span></span></code></pre></div><h2 id="自动显示变量值">
自动显示变量值
<a class="anchor" href="#%e8%87%aa%e5%8a%a8%e6%98%be%e7%a4%ba%e5%8f%98%e9%87%8f%e5%80%bc">#</a>
</h2>
<p><code>display</code> 命令支持自动显示变量值功能。当进行 <code>next</code> 或者 <code>step</code> 等调试操作时候，GDB会自动显示 <code>display</code> 所设置的变量或者地址的值信息。</p>
<p><code>display</code> 命令格式：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span>display &lt;expr&gt;
</span></span><span style="display:flex;"><span>display /&lt;fmt&gt; &lt;expr&gt;
</span></span><span style="display:flex;"><span>display /&lt;fmt&gt; &lt;addr&gt;
</span></span></code></pre></div><ul>
<li>expr是一个表达式</li>
<li>fmt表示显示的格式</li>
<li>addr表示内存地址</li>
</ul>
<p>其他相关命令：</p>
<ul>
<li>undisplay [num]: 不显示</li>
<li>delete display [num]: 删除</li>
<li>disable display [num]: 关闭自动显示</li>
<li>enable display [num]： 开启自动显示</li>
<li>info display: 查看display信息</li>
</ul>
<p><strong>注意：</strong> 当不带display号时候，是针对所有display进行设置。</p>
<h2 id="显示将要执行的汇编指令">
显示将要执行的汇编指令
<a class="anchor" href="#%e6%98%be%e7%a4%ba%e5%b0%86%e8%a6%81%e6%89%a7%e8%a1%8c%e7%9a%84%e6%b1%87%e7%bc%96%e6%8c%87%e4%bb%a4">#</a>
</h2>
<p>我们可以通过 <code>display</code> 命令可以实现当程序停止时，查看将要执行的汇编指令：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> display /i $pc
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> display /3i $pc <span style="color:#75715e"># 一次性显示3条指令</span>
</span></span></code></pre></div><p>取消显示可以用 <code>undisplay</code> 命令进行操作。</p>
<h2 id="查看backtrace信息">
查看backtrace信息
<a class="anchor" href="#%e6%9f%a5%e7%9c%8bbacktrace%e4%bf%a1%e6%81%af">#</a>
</h2>
<p><code>backtrace</code> 命令用来查看栈帧信息。可以简写成 <code>bt</code>。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> backtrace <span style="color:#75715e"># 显示当前函数的栈帧以及局部变量信息</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> backtrace full <span style="color:#75715e"># 显示各个函数的栈帧以及局部变量值</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> backtrace full n <span style="color:#75715e"># 从内向外显示n个栈桢，及其局部变量</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> backtrace full -n <span style="color:#75715e"># 从外向内显示n个栈桢，及其局部变量</span>
</span></span></code></pre></div><h2 id="切换栈帧信息">
切换栈帧信息
<a class="anchor" href="#%e5%88%87%e6%8d%a2%e6%a0%88%e5%b8%a7%e4%bf%a1%e6%81%af">#</a>
</h2>
<p><code>frame</code> 命令可以切换栈帧信息：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> frame n <span style="color:#75715e"># 其中n是层数，最内层的函数帧为第0帧</span>
</span></span></code></pre></div><p>其他相关命令：</p>
<ul>
<li>info frame: 查看栈帧列表</li>
</ul>
<h2 id="调试多线程">
调试多线程
<a class="anchor" href="#%e8%b0%83%e8%af%95%e5%a4%9a%e7%ba%bf%e7%a8%8b">#</a>
</h2>
<p>GDB中有一组命令能够辅助多线程的调试：</p>
<ul>
<li>
<p>info threads</p>
<p>显示当前可调式的所有线程，线程 ID 前有 “*” 表示当前被调试的线程。</p>
</li>
<li>
<p>thread threadid</p>
<p>切换线程到线程threadid</p>
</li>
<li>
<p>set scheduler-locking [on|off|step]</p>
<p>多线程环境下，会存在多个线程运行，这会影响调试某个线程的结果，这个命令可以设置调试的时候多个线程的运行情况，<code>on</code> 表示只有当前调试的线程会继续执行，<code>off</code> 表示不屏蔽任何线程，所有线程都可以执行，<code>step</code> 表示在单步执行时，只有当前线程会执行。</p>
</li>
<li>
<p>thread apply [threadid] [all] args</p>
<p>对线程列表执行命令。比如通过 <code>thread apply all bt full</code> 可以查看所有线程的局部变量信息。</p>
</li>
</ul>
<h2 id="查看运行时变量">
查看运行时变量
<a class="anchor" href="#%e6%9f%a5%e7%9c%8b%e8%bf%90%e8%a1%8c%e6%97%b6%e5%8f%98%e9%87%8f">#</a>
</h2>
<p><code>print</code> 命令可以用来查看变量的值。<code>print</code> 命令可以简写成 <code>p</code>。<code>print</code> 命令格式如下：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span>print <span style="color:#f92672">[</span>&lt;/format&gt;<span style="color:#f92672">]</span> &lt;expr&gt;
</span></span></code></pre></div><p><code>format</code> 用来设置显示变量的格式，是可选的选项。其可用值如下所示：</p>
<ul>
<li>x 按十六进制格式显示变量</li>
<li>d 按十进制格式显示变量</li>
<li>u 按十六进制格式显示无符号整型</li>
<li>o 按八进制格式显示变量</li>
<li>t 按二进制格式显示变量</li>
<li>a 按十六进制格式显示变量</li>
<li>c 按字符格式显示变量</li>
<li>f 按浮点数格式显示变量</li>
<li>z 按十六进制格式显示变量，左侧填充零</li>
</ul>
<p><code>expr</code> 可以是一个变量，也可以是表达式，也可以是寄存器：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> p var1 <span style="color:#75715e"># 打印变量var1</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> p &amp;var1 <span style="color:#75715e"># 打印变量var1地址</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> p $rsp <span style="color:#75715e"># 打印rsp寄存器地址</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> p $rsp + <span style="color:#ae81ff">8</span> <span style="color:#75715e"># 打印rsp加8后的地址信息</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> p 0xc000068fd0 <span style="color:#75715e"># 打印0xc000068fd0转换成10进制格式</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> p /x <span style="color:#ae81ff">824634150864</span> <span style="color:#75715e"># 打印824634150864转换成16进制格式</span>
</span></span></code></pre></div><p><code>print</code> 也支持查看连续内存，<code>@</code> 操作符用于查看连续内存，<code>@</code> 的左边是第一个内存的地址的值，<code>@</code> 的右边则想查看内存的长度。</p>
<p>例如对于如下代码：<code>int arr[] = {2, 4, 6, 8, 10};</code>，可以通过如下命令查看 <code>arr</code> 前三个单元的数据：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> p *arr@3
</span></span><span style="display:flex;"><span>$2 <span style="color:#f92672">=</span> <span style="color:#f92672">{</span>2, 4, 6<span style="color:#f92672">}</span>
</span></span></code></pre></div><h2 id="查看内存中的值">
查看内存中的值
<a class="anchor" href="#%e6%9f%a5%e7%9c%8b%e5%86%85%e5%ad%98%e4%b8%ad%e7%9a%84%e5%80%bc">#</a>
</h2>
<p><code>examine</code> 命令用来查看内存地址中的值，可以简写成 <code>x</code>。<code>examine</code> 命令的语法如下所示：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span>examine /&lt;n/f/u&gt; &lt;addr&gt;
</span></span></code></pre></div><ul>
<li>
<p>n 表示显示字段的长度，也就是说从当前地址向后显示几个地址的内容。</p>
</li>
<li>
<p>f 表示显示的格式</p>
<ul>
<li>d 数字 decimal</li>
<li>u 无符号数字 unsigned decimal</li>
<li>s 字符串 string</li>
<li>c 字符 char</li>
<li>u 无符号整数 unsigned integer</li>
<li>t 二进制 binary</li>
<li>o 八进制格式 octal</li>
<li>x 十六进制格式 hex</li>
<li>f 浮点数格式 float</li>
<li>i 指令 instruction</li>
<li>a 地址 address</li>
<li>z 十六进制格式，左侧填充零 hex, zero padded on the left</li>
</ul>
</li>
<li>
<p>u 表示从当前地址往后请求的字节数，默认是4个bytes</p>
<ul>
<li>b 一个字节 byte</li>
<li>h 两个字节 halfword</li>
<li>w 四个字节 word</li>
<li>g 八个字节 giantword</li>
</ul>
</li>
</ul>
<p>示例：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> x/10c 0x4005d4 <span style="color:#75715e"># 打印前10个字符</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> x/16xb a <span style="color:#75715e"># 以16进制格式打印数组前a16个byte的值</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> x/16ub a <span style="color:#75715e"># 以无符号10进制格式打印数组a前16个byte的值</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> x/16tb a <span style="color:#75715e"># 以2进制格式打印数组前16个abyte的值</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> x/16xw a <span style="color:#75715e"># 以16进制格式打印数组a前16个word（4个byte）的值</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> x $rsp <span style="color:#75715e"># 打印rsp寄存器执行的地址的值</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> x $rsp + <span style="color:#ae81ff">8</span> <span style="color:#75715e"># 打印rsp加8后的地址指向的值</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> x 0xc000068fd0 <span style="color:#75715e"># 打印内存0xc000068fd0指向的值</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> x/5i schedule <span style="color:#75715e"># 打印函数schedule前5条指令</span>
</span></span></code></pre></div><h2 id="修改变量或寄存器值">
修改变量或寄存器值
<a class="anchor" href="#%e4%bf%ae%e6%94%b9%e5%8f%98%e9%87%8f%e6%88%96%e5%af%84%e5%ad%98%e5%99%a8%e5%80%bc">#</a>
</h2>
<p><code>set</code> 命令支持修改变量以及寄存器的值：</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> set var var1<span style="color:#f92672">=</span><span style="color:#ae81ff">123</span> <span style="color:#75715e"># 设置变量var1值为123</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> set var $rax<span style="color:#f92672">=</span><span style="color:#ae81ff">123</span> <span style="color:#75715e"># 设置寄存器值为123</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> set environment envname1<span style="color:#f92672">=</span><span style="color:#ae81ff">123</span> <span style="color:#75715e"># 设置环境变量envname1值为123</span>
</span></span></code></pre></div><h2 id="查看命令帮助信息">
查看命令帮助信息
<a class="anchor" href="#%e6%9f%a5%e7%9c%8b%e5%91%bd%e4%bb%a4%e5%b8%ae%e5%8a%a9%e4%bf%a1%e6%81%af">#</a>
</h2>
<p><code>help</code> 命令支持查看GDB命令帮助信息。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> help status <span style="color:#75715e"># 查看所有命令使用示例</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> help x <span style="color:#75715e"># 查看x命令使用帮助</span>
</span></span></code></pre></div><h2 id="搜索源文件">
搜索源文件
<a class="anchor" href="#%e6%90%9c%e7%b4%a2%e6%ba%90%e6%96%87%e4%bb%b6">#</a>
</h2>
<p><code>search</code> 命令支持在当前文件中使用正则表达式搜索内容。<code>search</code> 等效于 <code>forward-search</code> 命令，是从当前位置向前搜索，可以简写成 <code>fo</code>。<code>reverse-search</code> 命令功能跟 <code>forward-search</code> 恰好相反，其可以简写成 <code>rev</code>。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> search func add <span style="color:#75715e"># 从当前位置向前搜索add方法</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> rev func add <span style="color:#75715e"># 从当前为向后搜索add方法</span>
</span></span></code></pre></div><h2 id="执行shell命令">
执行shell命令
<a class="anchor" href="#%e6%89%a7%e8%a1%8cshell%e5%91%bd%e4%bb%a4">#</a>
</h2>
<p>我们可以通过 <code>shell</code> 指令来执行shell命令。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> shell cat /proc/27889/maps <span style="color:#75715e"># 查看进程27889的内存映射。若想查看当前进程id，可以使用info proc命令获取</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> shell ls -alh
</span></span></code></pre></div><h2 id="gdb对go-runtime支持">
GDB对go runtime支持
<a class="anchor" href="#gdb%e5%af%b9go-runtime%e6%94%af%e6%8c%81">#</a>
</h2>
<ul>
<li>runtime.Breakpoint()：触发调试器断点。</li>
<li>runtime/debug.PrintStack()：显示调试堆栈。</li>
<li>log：适合替代 print显示调试信息</li>
</ul>
<h2 id="为系统调用设置捕获点">
为系统调用设置捕获点
<a class="anchor" href="#%e4%b8%ba%e7%b3%bb%e7%bb%9f%e8%b0%83%e7%94%a8%e8%ae%be%e7%bd%ae%e6%8d%95%e8%8e%b7%e7%82%b9">#</a>
</h2>
<p>GDB支持为系统调用设置捕获点(catchpoint)，我们可以通过 <code>catch</code> 指令，后面加上 <strong>系统调用号(syscall numbers)</strong><sup id="fnref:1"><a href="#fn:1" class="footnote-ref" role="doc-noteref">1</a></sup> 或者<strong>系统调用助记符(syscall mnemonic names，也称为系统调用名称)</strong> 来设置捕获点。如果不指定系统调用的话，默认是捕获所有系统调用。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-shell" data-lang="shell"><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> catch syscall <span style="color:#ae81ff">231</span>
</span></span><span style="display:flex;"><span>Catchpoint <span style="color:#ae81ff">1</span> <span style="color:#f92672">(</span>syscall <span style="color:#e6db74">&#39;exit_group&#39;</span> <span style="color:#f92672">[</span>231<span style="color:#f92672">])</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> catch syscall exit_group
</span></span><span style="display:flex;"><span>Catchpoint <span style="color:#ae81ff">2</span> <span style="color:#f92672">(</span>syscall <span style="color:#e6db74">&#39;exit_group&#39;</span> <span style="color:#f92672">[</span>231<span style="color:#f92672">])</span>
</span></span><span style="display:flex;"><span><span style="color:#f92672">(</span>gdb<span style="color:#f92672">)</span> catch syscall
</span></span><span style="display:flex;"><span>Catchpoint <span style="color:#ae81ff">3</span> <span style="color:#f92672">(</span>any syscall<span style="color:#f92672">)</span>
</span></span></code></pre></div><h2 id="设置源文件查找路径">
设置源文件查找路径
<a class="anchor" href="#%e8%ae%be%e7%bd%ae%e6%ba%90%e6%96%87%e4%bb%b6%e6%9f%a5%e6%89%be%e8%b7%af%e5%be%84">#</a>
</h2>
<p>在程序调试过程中，构建程序的源文件位置更改之后，gdb不能找到源文件位置，我们可以使用 <code>directory</code>命令设置查找源文件的路径。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span>directory ~/www/go/src/github.com/go-delve/
</span></span></code></pre></div><p><code>directory</code> 命令只使用相对路径下的源文件，若绝对路径下源文件找不到，我们可以使用 <code>set substitute-path</code> 设置路径替换。</p>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span>set substitute-path ~/www/go/src/github.com/go-delve/ ~/www/go/src/github.com/go-delve2/
</span></span></code></pre></div><h2 id="批量执行命令">
批量执行命令
<a class="anchor" href="#%e6%89%b9%e9%87%8f%e6%89%a7%e8%a1%8c%e5%91%bd%e4%bb%a4">#</a>
</h2>
<p>GDB支持以脚本形式运行命令，我们可以使用下面的选项：</p>
<ul>
<li><code>-ex</code>选项可以用来指定执行命令</li>
<li><code>-iex</code>选来用来指定加载应用程序之前需执行的命令</li>
<li><code>-x</code> 选项用来从指定文件中加载命令</li>
<li><code>-batch</code>类似<code>-q</code>，支持安静模式，会指示GDB在所有命令执行完成之后，退出</li>
</ul>
<div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-bash" data-lang="bash"><span style="display:flex;"><span><span style="color:#75715e"># 1. 打印提示语 2. 在main.main出设置断点 3. 运行程序 4. 执行完成程序退出gdb</span>
</span></span><span style="display:flex;"><span>gdb -iex <span style="color:#e6db74">&#39;echo 开始执行:\n&#39;</span> -ex <span style="color:#e6db74">&#34;b main.main&#34;</span> -ex <span style="color:#e6db74">&#34;run&#34;</span> -batch ./main
</span></span><span style="display:flex;"><span>
</span></span><span style="display:flex;"><span><span style="color:#75715e"># 设置exit/exit_group系统调用追踪点，然后运行程序，最后打印backtrace信息</span>
</span></span><span style="display:flex;"><span>gdb -ex <span style="color:#e6db74">&#34;catch syscall exit exit_group&#34;</span> -ex <span style="color:#e6db74">&#34;run&#34;</span> -ex <span style="color:#e6db74">&#34;bt&#34;</span> -batch ./main
</span></span><span style="display:flex;"><span>
</span></span><span style="display:flex;"><span><span style="color:#75715e"># 从文件中加载命令</span>
</span></span><span style="display:flex;"><span>gdb -batch -x /tmp/cmds --args executablename arg1 arg2 arg3
</span></span></code></pre></div><h2 id="gdb增强插件">
GDB增强插件
<a class="anchor" href="#gdb%e5%a2%9e%e5%bc%ba%e6%8f%92%e4%bb%b6">#</a>
</h2>
<ul>
<li>
<a href="https://github.com/gdbinit/gdbinit">gdbinit</a></li>
<li>
<a href="https://github.com/cyrus-and/gdb-dashboard">gdb-dashboard</a></li>
<li>
<a href="https://github.com/pwndbg/pwndbg">pwndbg</a></li>
<li>
<a href="https://github.com/longld/peda">peda</a></li>
</ul>
<h2 id="进一步阅读">
进一步阅读
<a class="anchor" href="#%e8%bf%9b%e4%b8%80%e6%ad%a5%e9%98%85%e8%af%bb">#</a>
</h2>
<ul>
<li>
<a href="http://beej.us/guide/bggdb/">Beej&rsquo;s Quick Guide to GDB</a></li>
<li>
<a href="https://wizardforcel.gitbooks.io/100-gdb-tips/content/index.html">100个gdb小技巧</a></li>
</ul>
<div class="footnotes" role="doc-endnotes">
<hr>
<ol>
<li id="fn:1">
<p>
<a href="https://x64.syscall.sh/">https://x64.syscall.sh/</a>&#160;<a href="#fnref:1" class="footnote-backref" role="doc-backlink">&#x21a9;&#xfe0e;</a></p>
</li>
</ol>
</div>
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