{"id":341,"date":"2024-08-06T12:30:56","date_gmt":"2024-08-06T04:30:56","guid":{"rendered":"http:\/\/114.55.108.251\/?p=341"},"modified":"2025-03-04T09:46:25","modified_gmt":"2025-03-04T01:46:25","slug":"linux%e7%b3%bb%e7%bb%9f%e7%bc%96%e7%a8%8b-part5-%ef%bc%88%e9%80%92%e5%bd%92%e9%81%8d%e5%8e%86%e7%9b%ae%e5%bd%95%e7%bb%83%e4%b9%a0%e3%80%81dup2%e3%80%81%e8%bf%9b%e7%a8%8b%ef%bc%89","status":"publish","type":"post","link":"https:\/\/guapicoding.com\/?p=341","title":{"rendered":"Linux\u7cfb\u7edf\u7f16\u7a0b Part5 \uff08dup2\u91cd\u5b9a\u5411\u3001\u8fdb\u7a0b\uff09"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">\u91cd\u5b9a\u5411<\/h2>\n\n\n\n<p>\u6982\u5ff5\uff1a\u5728 Linux\u7cfb\u7edf\u4e2d\uff0c\u91cd\u5b9a\u5411\u662f\u5c06\u547d\u4ee4\u7684\u8f93\u5165\u6216\u8f93\u51fa\u4ece\u9ed8\u8ba4\u7684\u7ec8\u7aef\u8bbe\u5907\uff08\u5982\u5c4f\u5e55\uff09\u91cd\u5b9a\u5411\u5230\u5176\u4ed6\u4f4d\u7f6e\uff08\u5982\u6587\u4ef6\uff09\u6216\u4ece\u5176\u4ed6\u4f4d\u7f6e\u8bfb\u53d6\u6570\u636e\u3002\u5e38\u89c1\u7684\u91cd\u5b9a\u5411\u64cd\u4f5c\u5305\u62ec\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u8f93\u51fa\u91cd\u5b9a\u5411<\/strong>\uff1a\u5c06\u547d\u4ee4\u7684\u8f93\u51fa\u5199\u5165\u6587\u4ef6\uff0c\u800c\u4e0d\u662f\u663e\u793a\u5728\u7ec8\u7aef\u4e0a<\/li>\n\n\n\n<li><strong>\u8ffd\u52a0\u91cd\u5b9a\u5411<\/strong>\uff1a\u5c06\u8f93\u51fa\u8ffd\u52a0\u5230\u6587\u4ef6\u672b\u5c3e\uff0c\u800c\u4e0d\u662f\u8986\u76d6 <\/li>\n\n\n\n<li><strong>\u8f93\u5165\u91cd\u5b9a\u5411<\/strong>\uff1a\u4ece\u6587\u4ef6\u4e2d\u8bfb\u53d6\u8f93\u5165\uff0c\u800c\u4e0d\u662f\u4ece\u7ec8\u7aef\u952e\u76d8\u8f93\u5165 <\/li>\n<\/ul>\n\n\n\n<p>\u8fd9\u4e9b\u91cd\u5b9a\u5411\u7b26\u53f7\u5206\u522b\u662f <code>&gt;<\/code>\uff08\u8f93\u51fa\u91cd\u5b9a\u5411\uff09\u3001<code>&gt;&gt;<\/code>\uff08\u8ffd\u52a0\u91cd\u5b9a\u5411\uff09\u548c <code>&lt;<\/code>\uff08\u8f93\u5165\u91cd\u5b9a\u5411\uff09 <\/p>\n\n\n\n<h2 class=\"wp-block-heading\">dup\/dup2\u51fd\u6570<\/h2>\n\n\n\n<p><code>int dup(int oldfd);<\/code> \u6587\u4ef6\u63cf\u8ff0\u7b26\u590d\u5236<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>oldfd<\/code>\uff1a\u5df2\u6709\u6587\u4ef6\u63cf\u8ff0\u7b26<\/li>\n\n\n\n<li>\u8fd4\u56de\u503c\uff1a\u65b0\u6587\u4ef6\u63cf\u8ff0\u7b26<\/li>\n<\/ul>\n\n\n\n<p><code><strong>int dup2(int oldfd, int newfd); <\/strong><\/code>\u6587\u4ef6\u63cf\u8ff0\u7b26\u590d\u5236\u3001\u91cd\u5b9a\u5411\uff08\u65b0\u6587\u4ef6\u63cf\u8ff0\u7b26\u4e5f\u6307\u5411\u539f\u6587\u4ef6\uff0c\u5373\u540e\u9762\u6307\u5411\u524d\u9762\uff09<\/p>\n\n\n\n<p>\u6bd4\u5982\uff1a<code>dup2(fd1, STDOUT_FILENO); <\/code>\/\/\u5c06\u5c4f\u5e55\u8f93\u5165\u91cd\u5b9a\u5411\u7ed9fd1\u6240\u6307\u5411\u7684\u6587\u4ef6\uff0c\u6587\u4ef6\u63cf\u8ff0\u7b26\u5982\u4e0b\u56fe\u6240\u793a\uff08\u4ee5fd1 = 3\u4e3a\u4f8b\uff09\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/guapicoding.com\/wp-content\/uploads\/2024\/09\/1726384946060.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  loading=\"lazy\" decoding=\"async\" width=\"450\" height=\"513\" data-original=\"https:\/\/guapicoding.com\/wp-content\/uploads\/2024\/09\/1726384946060.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" class=\"wp-image-379\"  sizes=\"auto, (max-width: 450px) 100vw, 450px\" \/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">fcntl \u51fd\u6570\u5b9e\u73b0 dup\uff1a<\/h4>\n\n\n\n<p><code>int fcntl(int fd, int cmd, \u2026)<\/code>\u53c23\u7531\u53c22\u5177\u4f53\u547d\u4ee4\u51b3\u5b9a <\/p>\n\n\n\n<p>\u5728\u8fd9\u91cc\u8981\u5b9e\u73b0dup\u529f\u80fd\uff0c\u53c22\u4e3aF_DUPFD\uff0c\u53c23\u6307\u5b9a\u590d\u5236\u4f53\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\uff08\u82e5\u5df2\u88ab\u5360\u7528\uff0c\u5219\u8fd4\u56de\u6700\u5c0f\u53ef\u7528\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26\uff09<\/p>\n\n\n\n<p>\u6bd4\u5982\uff1a<code>int fcntl(fd1, F_DUPFD, 5);<\/code><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u8fdb\u7a0b\u63a7\u5236<\/h2>\n\n\n\n<p>\u7a0b\u5e8f\u548c\u8fdb\u7a0b\u7684\u533a\u522b\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u7a0b\u5e8f\u662f\u7f16\u8bd1\u597d\u7684\u4e8c\u8fdb\u5236\u6587\u4ef6\uff08\u6b7b\u7684\uff09\uff0c\u53ea\u5360\u7528\u78c1\u76d8\u7a7a\u95f4\uff0c\u4e0d\u5360\u7528\u7cfb\u7edf\u8d44\u6e90<\/li>\n\n\n\n<li>\u8fdb\u7a0b\u662f\u8fd0\u884c\u8d77\u6765\u7684\u7a0b\u5e8f\uff08\u6d3b\u7684\uff09\uff0c\u5360\u7528\u5185\u5b58\u3001cpu\u7b49\u7cfb\u7edf\u8d44\u6e90<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u865a\u62df\u5185\u5b58\u548c\u7269\u7406\u5185\u5b58\u6620\u5c04\u5173\u7cfb<\/h4>\n\n\n\n<p>ps\uff1a\u4ee532\u4f4d\u7cfb\u7edf\u4e3e\u4f8b\uff0c\u8fdb\u7a0b\u5730\u5740\u7a7a\u95f4\u5927\u5c0f\u4e3a2\u768432\u6b21\u65b9byte\uff0c\u53730~4GB<\/p>\n\n\n\n<p>MMU\uff08Memory Management Unit\uff0c\u5185\u5b58\u7ba1\u7406\u5355\u5143\uff09\u662f\u8ba1\u7b97\u673a\u7cfb\u7edf\u4e2d\u7684\u4e00\u4e2a\u786c\u4ef6\u7ec4\u4ef6\uff0c\u4f4d\u4e8eCPU\u5185\uff0c\u8d1f\u8d23\u865a\u62df\u5185\u5b58\u548c\u7269\u7406\u5185\u5b58\u4e4b\u95f4\u7684\u6620\u5c04\u3002<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/guapicoding.com\/wp-content\/uploads\/2024\/09\/\u7269\u7406\u5185\u5b58\u548c\u865a\u62df\u5185\u5b58-1024x508.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"508\" data-original=\"https:\/\/guapicoding.com\/wp-content\/uploads\/2024\/09\/\u7269\u7406\u5185\u5b58\u548c\u865a\u62df\u5185\u5b58-1024x508.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" class=\"wp-image-363\"  sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/div><\/figure>\n\n\n\n<h4 class=\"wp-block-heading\">PCB\u8fdb\u7a0b\u63a7\u5236\u5757<\/h4>\n\n\n\n<p>\u6bcf\u4e2a\u8fdb\u7a0b\u5728\u5185\u6838\u90fd\u6709\u4e00\u4e2a\u8fdb\u7a0b\u63a7\u5236\u5757\uff08PCB\uff09\u6765\u7ef4\u62a4\u8fdb\u7a0b\u76f8\u5173\u7684\u4fe1\u606f\uff0cLinux\u5185\u6838\u7684\u8fdb\u7a0b\u63a7\u5236\u5757\u662ftask struct\u7ed3\u6784\u4f53\uff0c\u5185\u90e8\u6210\u5458\u5f88\u591a\uff0c\u91cd\u70b9\u638c\u63e1\u4ee5\u4e0b\u51e0\u4e2a\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u8fdb\u7a0bid<\/strong>\uff1a\u7cfb\u7edf\u4e2d\u6bcf\u4e2a\u8fdb\u7a0b\u6709\u552f\u4e00\u7684id\uff0c\u5373PID<\/li>\n\n\n\n<li><strong>\u8fdb\u7a0b\u72b6\u6001<\/strong>\uff1a\u521d\u59cb\u3001\u5c31\u7eea\u3001\u6302\u8d77\u3001\u8fd0\u884c\u3001\u505c\u6b62<\/li>\n\n\n\n<li>\u8fdb\u7a0b\u5207\u6362\u65f6\u9700\u8981\u4fdd\u5b58\u548c\u6062\u590d\u7684\u4e00\u4e9bCPU\u5bc4\u5b58\u5668<\/li>\n\n\n\n<li>\u63cf\u8ff0\u865a\u62df\u5730\u5740\u7a7a\u95f4\u7684\u4fe1\u606f<\/li>\n\n\n\n<li>\u63cf\u8ff0\u63a7\u5236\u7ec8\u7aef\u7684\u4fe1\u606f<\/li>\n\n\n\n<li><strong>\u5f53\u524d\u5de5\u4f5c\u76ee\u5f55\u4f4d\u7f6e<\/strong><\/li>\n\n\n\n<li>umask\u63a9\u7801<\/li>\n\n\n\n<li><strong>\u6587\u4ef6\u63cf\u8ff0\u7b26\u8868<\/strong><\/li>\n\n\n\n<li>\u548c\u4fe1\u53f7\u76f8\u5173\u7684\u4fe1\u606f<\/li>\n\n\n\n<li><strong>\u7528\u6237id\u548c\u7ec4id<\/strong><\/li>\n\n\n\n<li>\u4f1a\u8bdd\u548c\u8fdb\u7a0b\u7ec4<\/li>\n\n\n\n<li>\u8fdb\u7a0b\u53ef\u4ee5\u4f7f\u7528\u7684\u8d44\u6e90\u4e0a\u9650<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u4e09\u4e2a\u8fdb\u7a0b\u51fd\u6570<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code><strong>pid_t fork(void)<\/strong><\/code>\uff1a<strong>\u521b\u5efa\u5b50\u8fdb\u7a0b<\/strong>\uff0c<code>fork<\/code>\u8c03\u7528\u7684\u8fd4\u56de\u503c\u5728\u7236\u8fdb\u7a0b\u548c\u5b50\u8fdb\u7a0b\u4e2d\u662f\u4e0d\u540c\u7684\uff08\u7236\u8fdb\u7a0b\u8fd4\u56de\u5b50\u8fdb\u7a0bpid\uff0c \u5b50\u8fdb\u7a0b\u8fd4\u56de0 \uff09<\/li>\n\n\n\n<li><code>pid_t getpid(void) <\/code>\uff1a\u83b7\u53d6\u8fdb\u7a0bid<\/li>\n\n\n\n<li><code>pid_t getppid(void) <\/code>\uff1a\u83b7\u53d6\u7236\u8fdb\u7a0bid<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u203b\u5faa\u73af\u521b\u5efaN\u4e2a\u5b50\u8fdb\u7a0b\u6a21\u578b<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>#include &lt;stdio.h&gt;\n#include &lt;stdlib.h&gt;\n#include &lt;string.h&gt;\n#include &lt;unistd.h&gt;\n#include &lt;pthread.h&gt;\n\nint main(int argc, char *argv&#91;]) {\n    int i;\n    pid_t pid;\n\n    for (i = 0; i &lt; 5; i++) {       \n        if (fork() == 0)        \/\/\u5faa\u73af\u671f\u95f4 \u5b50\u8fdb\u7a0b\u4e0dfork\n            break;\n    }\n    if (5 == i) {       \/\/\u7236\u8fdb\u7a0b  \n        sleep(5);\n        printf(\"I'm parent \\n\");\n    } else {            \/\/\u5b50\u8fdb\u7a0b \u4ecebreak\u8df3\u51fa\n        sleep(i);\n        printf(\"I'm %dth child\\n\", i+1);\n    }\n\n    return 0;\n}\n<\/code><\/pre>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/guapicoding.com\/wp-content\/uploads\/2024\/09\/fork\u51fd\u6570-1024x508.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"508\" data-original=\"https:\/\/guapicoding.com\/wp-content\/uploads\/2024\/09\/fork\u51fd\u6570-1024x508.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" class=\"wp-image-362\" style=\"width:840px;height:auto\"  sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/div><\/figure>\n\n\n\n<p>ps\uff1a<code>fork<\/code>\u4e4b\u540e\u7236\u8fdb\u7a0b\u548c\u5b50\u8fdb\u7a0b\u4e0d\u4e00\u5b9a\u8c01\u5148\u6267\u884c\uff0c\u8fd9\u53d6\u51b3\u4e8e\u5185\u6838\u6240\u4f7f\u7528\u7684\u8c03\u5ea6\u7b97\u6cd5\uff08\u56e0\u6b64\u5728\u4e0a\u9762\u4ee3\u7801\u4e2d\u4f7f\u7528<code>sleep<\/code>\u51fd\u6570\u8ba9\u7236\u8fdb\u7a0b\u5148\u7761\u7720\uff09<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">gdb\u8c03\u8bd5\u7236\u5b50\u8fdb\u7a0b<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u8bbe\u7f6e\u7236\u8fdb\u7a0b\u8c03\u8bd5\u8def\u5f84\uff1aset follow-fork-mode parent (\u9ed8\u8ba4)<\/li>\n\n\n\n<li>\u8bbe\u7f6e\u5b50\u8fdb\u7a0b\u8c03\u8bd5\u8def\u5f84\uff1aset follow-fork-mode child<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u7236\u5b50\u8fdb\u7a0b\u5171\u4eab<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u76f8\u540c\uff1a\u521afork\u540e\u7684\uff1adata\u6bb5\u3001text\u6bb5\u3001\u5806\u3001\u6808\u3001\u73af\u5883\u53d8\u91cf\u3001\u5168\u5c40\u53d8\u91cf\u3001\u5bbf\u4e3b\u76ee\u5f55\u4f4d\u7f6e\u3001\u8fdb\u7a0b\u5de5\u4f5c\u76ee\u5f55\u4f4d\u7f6e\u3001\u4fe1\u53f7\u5904\u7406\u65b9\u5f0f<\/li>\n\n\n\n<li>\u4e0d\u540c\uff1a\u8fdb\u7a0bid\u3001fork\u8fd4\u56de\u503c\u3001\u5404\u81ea\u7684\u7236\u8fdb\u7a0b\u3001\u8fdb\u7a0b\u521b\u5efa\u65f6\u95f4\u3001\u5b9a\u65f6\u5668\u3001\u672a\u51b3\u4fe1\u53f7\u96c6<\/li>\n\n\n\n<li>\u5171\u4eab\uff1a\u6587\u4ef6\u63cf\u8ff0\u7b26\u3001mmap\u6620\u5c04\u533a <\/li>\n<\/ul>\n\n\n\n<p>\u7236\u5b50\u8fdb\u7a0b\u9075\u5faa<strong>\u8bfb\u65f6\u5171\u4eab\u3001\u5199\u65f6\u590d\u5236<\/strong>\u7684\u539f\u5219\uff0c\u56e0\u6b64\u7236\u5b50\u8fdb\u7a0b\u5e76\u4e0d\u5171\u4eab\u5168\u5c40\u53d8\u91cf\uff08\u5f53\u7136\u5982\u679c\u90fd\u53ea\u662f\u8bfb\u7684\u8bdd\u4e5f\u53ef\u4ee5\u7406\u89e3\u4e3a\u5171\u4eab\uff09 <\/p>\n\n\n\n<h2 class=\"wp-block-heading\">exec\u51fd\u6570\u65cf<\/h2>\n\n\n\n<p>\u6307\u5b9a\u8fdb\u7a0b\u6267\u884c\u67d0\u4e00\u7a0b\u5e8f\uff0c<code>exec<\/code>\u51fd\u6570\u4e00\u65e6\u8c03\u7528\u6210\u529f\u5c31\u6267\u884c\u65b0\u7684\u7a0b\u5e8f\uff0c\u4e0d\u4f1a\u8fd4\u56de\uff0c\u53ea\u6709\u8c03\u7528\u5931\u8d25\u624d\u8fd4\u56de -1\uff08<code>exec<\/code>\u51fd\u6570\u65cf\u90fd\u662f\u5e93\u51fd\u6570\uff0c\u5728man page\u7b2c\u4e09\u5377\uff0c\u91cd\u70b9\u638c\u63e1\u4ee5\u4e0b\u4e09\u4e2a\uff09<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><code>int execl<strong>p<\/strong>(const char *file, const char *arg, \u2026); <\/code>\u501f\u52a9PATH\u73af\u5883\u53d8\u91cf\u627e\u5bfb\u5f85\u6267\u884c\u7a0b\u5e8f\uff08\u51fd\u6570\u540d\u7684\u6700\u540e\u4e00\u4e2a\u5b57\u6bcdp\u6307\u7684\u5c31\u662fPATH\uff0c\u8be5\u51fd\u6570\u901a\u5e38\u7528\u6765\u8c03\u7528\u7cfb\u7edf\u7a0b\u5e8f\uff0c\u5982\uff1a<code>ls<\/code>\u3001<code>date<\/code>\u3001<code>cat<\/code>\u7b49\u547d\u4ee4\uff09\uff0c\u793a\u4f8b\uff1a<code>execlp(\"ls\", \"ls\", \"-l\", \"-h\", NULL);<\/code>\n<ul class=\"wp-block-list\">\n<li>\u53c2\u65701\uff1a\u7a0b\u5e8f\u540d<\/li>\n\n\n\n<li>\u53c2\u65702\uff1aargv[0]\uff08\u56e0\u6b64\u8c03\u7528\u51fd\u6570\u65f6\u4f1a\u51fa\u73b0\u4e24\u6b21\u7a0b\u5e8f\u540d\uff09<\/li>\n\n\n\n<li>\u53c2\u65703\uff1aargv[1]<\/li>\n\n\n\n<li>\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\uff1aargv[n]<\/li>\n\n\n\n<li>\u54e8\u5175\uff1a<code>NULL<\/code>\uff08\u8868\u793a\u53c2\u6570\u7ed3\u675f\uff09<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><code>int execl(const char *path, const char *arg, \u2026); <\/code>\u81ea\u5df1\u6307\u5b9a\u5f85\u6267\u884c\u7a0b\u5e8f\u8def\u5f84\uff08\u5176\u5b83\u4e0e<code>execlp<\/code>\u51fd\u6570\u540c\u7406\uff09<\/li>\n\n\n\n<li><code>int execvp(const char *file, const char *argv[]); <\/code>\u63d0\u524d\u628a\u53d8\u53c2\u5c01\u88c5\u4e3a\u5b57\u7b26\u6307\u9488\u6570\u7ec4\uff08\u5176\u5b83\u4e0e<code>execlp<\/code>\u51fd\u6570\u540c\u7406\uff09\uff0c\u793a\u4f8b\uff1a<code>char *argv[] = {\"ls\", \"-l\", \"-h\", NULL};  execvp(\"ls\", argv);<\/code><\/li>\n<\/ol>\n\n\n\n<figure class=\"wp-block-image size-large\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/guapicoding.com\/wp-content\/uploads\/2024\/09\/exec\u51fd\u6570-1024x508.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"508\" data-original=\"https:\/\/guapicoding.com\/wp-content\/uploads\/2024\/09\/exec\u51fd\u6570-1024x508.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" class=\"wp-image-406\"  sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/div><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">\u56de\u6536\u5b50\u8fdb\u7a0b<\/h2>\n\n\n\n<p>\u5b50\u8fdb\u7a0b\u7684\u56de\u6536\u4e00\u822c\u7531\u7236\u8fdb\u7a0b\u6765\u5b8c\u6210\uff0c\u5f53\u5b50\u8fdb\u7a0b\u7ec8\u6b62\u65f6\uff0c\u4f1a\u5173\u95ed\u6240\u6709\u6587\u4ef6\u63cf\u8ff0\u7b26\uff0c\u91ca\u653e\u5728\u7528\u6237\u7a7a\u95f4\u5206\u914d\u7684\u5185\u5b58\uff0c\u4f46\u4f1a\u5c06PCB\u8fdb\u7a0b\u63a7\u5236\u5757\u6b8b\u7559\u5728\u5185\u6838\u4e2d\uff0c\u7236\u8fdb\u7a0b\u6709\u4e49\u52a1\u83b7\u53d6\u8fd9\u4e9b\u4fe1\u606f\uff0c\u7136\u540e\u5f7b\u5e95\u6e05\u9664\u6389\u8fd9\u4e2a\u8fdb\u7a0b<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u5b64\u513f\u8fdb\u7a0b<\/h4>\n\n\n\n<p>\u7236\u8fdb\u7a0b\u5148\u4e8e\u5b50\u8fdb\u7a0b\u7ed3\u675f\uff0c\u5219\u5b50\u8fdb\u7a0b\u6210\u4e3a\u5b64\u513f\u8fdb\u7a0b\uff0c\u6b64\u65f6\u5b50\u8fdb\u7a0b\u65b0\u7684\u7236\u8fdb\u7a0b\u4e3ainit\u8fdb\u7a0b\uff0c\u79f0\u4e3ainit\u8fdb\u7a0b\u9886\u517b\u5b64\u513f\u8fdb\u7a0b<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u50f5\u5c38\u8fdb\u7a0b<\/h4>\n\n\n\n<p>\u8fdb\u7a0b\u7ec8\u6b62\uff0c\u4f46\u7236\u8fdb\u7a0b\u5c1a\u672a\u56de\u6536\uff0c\u5b50\u8fdb\u7a0b\u6b8b\u7559\u8d44\u6e90\uff08PCB\uff09\u5b58\u653e\u5728\u5185\u6838\u4e2d\uff0c\u53d8\u6210\u50f5\u5c38\u8fdb\u7a0b\uff08\u7406\u8bba\u4e0a\u6765\u8bf4\uff0c\u6bcf\u4e2a\u8fdb\u7a0b\u90fd\u4f1a\u7ecf\u5386\u50f5\u5c38\u6001\uff0c\u56e0\u4e3a\u8fdb\u7a0b\u6b7b\u4ea1\u548c\u7236\u8fdb\u7a0b\u56de\u6536\u4e0d\u53ef\u80fd\u662f\u540c\u6b65\u7684\uff09<\/p>\n\n\n\n<p>ps\uff1a<code>kill<\/code>\u547d\u4ee4\u53ea\u80fd\u7ec8\u6b62\u6d3b\u7740\u7684\u8fdb\u7a0b\uff0c\u56e0\u6b64\u65e0\u6cd5\u7528<code>kill<\/code>\u547d\u4ee4\u6740\u6b7b\u50f5\u5c38\u8fdb\u7a0b\uff0c\u4e00\u822c\u4f7f\u7528<code>kill<\/code>\u547d\u4ee4\u6765\u6740\u6b7b\u50f5\u5c38\u8fdb\u7a0b\u7684\u7236\u8fdb\u7a0b\uff0c\u8fd9\u65f6init\u8fdb\u7a0b\u4f1a\u6765\u9886\u517b\u50f5\u5c38\u8fdb\u7a0b\uff0c\u53d1\u73b0\u50f5\u5c38\u8fdb\u7a0b\u7684\u8eab\u4efd\u540e\uff0cinit\u8fdb\u7a0b\u5c31\u4f1a\u5c06\u5b83\u56de\u6536<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">wait\u51fd\u6570<\/h4>\n\n\n\n<p>\u7236\u8fdb\u7a0b\u8c03\u7528<code>wait<\/code>\u51fd\u6570\u53ef\u4ee5\u56de\u6536\u5b50\u8fdb\u7a0b\u7ec8\u6b62\u4fe1\u606f\uff0c\u8be5\u51fd\u6570\u6709\u4e09\u4e2a\u529f\u80fd\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u963b\u585e\u7b49\u5f85\u5b50\u8fdb\u7a0b\u9000\u51fa\uff08\u5373\u4e00\u76f4\u7b49\u7740\u5b50\u8fdb\u7a0b\u6b7b\uff09<\/li>\n\n\n\n<li>\u56de\u6536\u5b50\u8fdb\u7a0b\u6b8b\u7559\u8d44\u6e90<\/li>\n\n\n\n<li>\u83b7\u53d6\u5b50\u8fdb\u7a0b\u7ed3\u675f\u72b6\u6001\uff08\u9000\u51fa\u539f\u56e0\uff09<\/li>\n<\/ul>\n\n\n\n<p><code>pid_t wait(int *status)<\/code>;<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u53c2\u6570\uff1a\u56de\u6536\u8fdb\u7a0b\u7684\u72b6\u6001\uff08\u4f20\u51fa\u53c2\u6570\uff09 \uff0c\u5982\u679c\u4e0d\u5173\u5fc3\u8fdb\u7a0b\u7684\u72b6\u6001\uff0c\u5c31\u8bbe\u7f6e\u4e3aNULL<\/li>\n\n\n\n<li>\u8fd4\u56de\u503c\uff1a\n<ul class=\"wp-block-list\">\n<li>\u6210\u529f\uff1a \u6210\u529f\u56de\u6536\u7684\u5b50\u8fdb\u7a0bpid<\/li>\n\n\n\n<li>\u5931\u8d25\uff1a -1\uff0c errno<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p>\u4f20\u51fa\u53c2\u6570<code>int *status<\/code>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u83b7\u53d6\u5b50\u8fdb\u7a0b\u6b63\u5e38\u7ec8\u6b62\u503c\uff1a<code>WIFEXITED(status)<\/code>&#8212;\u300b\u4e3a\u771f&#8212;\u300b\u8c03\u7528<code>WEXITSTATUS(status)<\/code>&#8212;\u300b\u5f97\u5230\u5b50\u8fdb\u7a0b\u9000\u51fa\u503c\uff08\u5373wait if exited\u548cwait exit status\uff09<\/li>\n\n\n\n<li>\u83b7\u53d6\u5bfc\u81f4\u5b50\u8fdb\u7a0b\u5f02\u5e38\u7ec8\u6b62\u4fe1\u53f7\uff1a<code>WIFSIGNALED(status)<\/code>&#8212;\u300b\u4e3a\u771f&#8212;\u300b\u8c03\u7528<code>WTERMSIG(status)<\/code>&#8212;\u300b\u5f97\u5230 \u5bfc\u81f4\u5b50\u8fdb\u7a0b\u5f02\u5e38\u7ec8\u6b62\u7684\u4fe1\u53f7\u7f16\u53f7\uff08\u5373wait if signaled\u548cwait termination signal\uff09<\/li>\n<\/ul>\n\n\n\n<p>\u5b8c\u6574\u4ee3\u7801\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#include&lt;stdio.h&gt;\n#include&lt;stdlib.h&gt;\n#include&lt;unistd.h&gt;\n#include&lt;sys\/wait.h&gt;\n\nint main(void) {\n    int status;\n    pid_t pid, wpid;\n    pid = fork();\n    if(pid == 0) { \/\/\u8fd4\u56de\u503c\u4e3a0\uff0c\u8bf4\u660e\u662f\u5b50\u8fdb\u7a0b\n        printf(\"i am child, my id is %d, going to sleep 10s\\n\",getpid()); \/\/\u83b7\u53d6\u5b50\u8fdb\u7a0b\u5b9e\u9645pid\n        sleep(10);\n        printf(\"child die\\n\");\n        return 5;\n    } else if(pid &gt; 0) {\n        wpid = wait(&amp;status);\n        if(wpid == -1) {\n            perror(\"wait error\");\n            exit(1);\n        }   \n        if(WIFEXITED(status)) { \/\/\u82e5\u4e3a\u771f\uff0c\u8bf4\u660e\u5b50\u8fdb\u7a0b\u6b63\u5e38\u7ec8\u6b62\n            printf(\"child exit with %d\\n\", WEXITSTATUS(status));\n        }   \n        if(WIFSIGNALED(status)) { \/\/\u82e5\u4e3a\u5047\uff0c\u8bf4\u660e\u5b50\u8fdb\u7a0b\u5f02\u5e38\u7ec8\u6b62\n            printf(\"child kill with signal %d\\n\", WTERMSIG(status));\n        }   \n    } else {\n        perror(\"fork\");\n        return 1;\n    }   \n}\n<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">waitpid\u51fd\u6570<\/h4>\n\n\n\n<p>\u6307\u5b9a\u67d0\u4e00\u4e2a\u8fdb\u7a0b\u8fdb\u884c\u56de\u6536\uff08\u53ef\u4ee5\u8bbe\u7f6e\u975e\u963b\u585e\uff09 <\/p>\n\n\n\n<p><code>pid_t waitpid(pid_t pid, int *status, int options)<\/code><\/p>\n\n\n\n<p>\u53c2\u6570\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>pid\uff1a\u6307\u5b9a\u56de\u6536\u7684\u67d0\u4e00\u4e2a\u5b50\u8fdb\u7a0bpid\n<ul class=\"wp-block-list\">\n<li>\uff1e0\uff1a\u6307\u5b9a\u56de\u6536\u7684\u5b50\u8fdb\u7a0bpid<\/li>\n\n\n\n<li>-1\uff1a\u8868\u793a\u56de\u6536\u4efb\u610f\u5b50\u8fdb\u7a0b\uff08\u76f8\u5f53\u4e8e<code>wait<\/code>\uff09<\/li>\n\n\n\n<li>0\uff1a\u8868\u793a\u56de\u6536\u540c\u8fdb\u7a0b\u7ec4\u7684\u5b50\u8fdb\u7a0b <\/li>\n\n\n\n<li>\uff1c-1\uff1a\u8868\u793a\u56de\u6536\u6307\u5b9a\u8fdb\u7a0b\u7ec4\u91cc\u7684\u4efb\u610f\u5b50\u8fdb\u7a0b<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>status\uff1a\uff08\u4f20\u51fa\u53c2\u6570\uff09\u56de\u6536\u8fdb\u7a0b\u7684\u72b6\u6001<\/li>\n\n\n\n<li>options\uff1aWNOHANG\uff08\u5373wait no hang\uff09\u6307\u5b9a\u56de\u6536\u65b9\u5f0f\u4e3a\u975e\u963b\u585e\uff0c0\u8868\u793a\u963b\u585e\uff08\u9ed8\u8ba4\uff09<\/li>\n<\/ul>\n\n\n\n<p>\u5f53\u8fd9\u6837\u8bbe\u7f6e<code>waitpid<\/code>\u51fd\u6570\u53c2\u6570\u65f6\uff0c\u5c31\u76f8\u5f53\u4e8e<code>wait<\/code>\u51fd\u6570\uff1a<code>waitpid(-1, &amp;status, 0) <\/code>== <code>wait(&amp;status)<\/code><\/p>\n\n\n\n<p>\u8fd4\u56de\u503c\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\uff1e0\uff1a\u6210\u529f\u56de\u6536\u7684\u5b50\u8fdb\u7a0bpid<\/li>\n\n\n\n<li>0\uff1a\u51fd\u6570\u8c03\u7528\u65f6\uff0c\u53c23\u6307\u5b9a\u4e86<code>WNOHANG<\/code>\uff0c\u5e76\u4e14\u6ca1\u6709\u7ed3\u675f\u7684\u5b50\u8fdb\u7a0b <\/li>\n\n\n\n<li>-1\uff1a\u56de\u6536\u5931\u8d25\uff0cerrno<\/li>\n<\/ul>\n\n\n\n<p>ps\uff1a<code>wait<\/code>\u3001<code>waitpid<\/code>\u51fd\u6570\u4e00\u6b21\u8c03\u7528\uff0c\u53ea\u80fd\u56de\u6536\u4e00\u4e2a\u5b50\u8fdb\u7a0b\uff0c\u5982\u679c\u60f3\u56de\u6536\u591a\u4e2a\u5b50\u8fdb\u7a0b\uff0c\u8981\u7528<code>while<\/code>\u5faa\u73af<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u73af\u5883\u53d8\u91cf<\/h2>\n\n\n\n<p>\u672c\u8d28\u4e0a\u662f\u64cd\u4f5c\u7cfb\u7edf\u4e2d\u7684\u4e00\u7ec4\u952e\u503c\u5bf9\uff08name = value\uff09\uff0c\u7528\u6765\u5b58\u50a8\u5f71\u54cd\u8fdb\u7a0b\u884c\u4e3a\u7684\u5173\u952e\u4fe1\u606f\uff08\u53ef\u7528\u547d\u4ee4<code>env<\/code>\u8f93\u51fa\u5168\u90e8\u73af\u5883\u53d8\u91cf\uff09\uff0c\u91cd\u70b9\u638c\u63e1\u4ee5\u4e0b\u51e0\u4e2a\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>PATH\uff1a\u53ef\u6267\u884c\u6587\u4ef6\u7684\u641c\u7d22\u8def\u5f84\uff08\u53ef\u7528\u547d\u4ee4<code>echo $PATH<\/code>\u8f93\u51fa\uff0c\u4ee5\u4e0b\u540c\u7406\uff09<\/li>\n\n\n\n<li>SHELL\uff1a\u5f53\u524dshell<\/li>\n\n\n\n<li>TERM\uff1a\u5f53\u524d\u7ec8\u7aef\u7c7b\u578b<\/li>\n\n\n\n<li>LANG\uff1a\u8bed\u8a00\u548clocale\uff0c\u51b3\u5b9a\u4e86\u5b57\u7b26\u7f16\u7801\u4ee5\u53ca\u65f6\u95f4\u3001\u8d27\u5e01\u7b49\u4fe1\u606f\u7684\u663e\u793a\u683c\u5f0f<\/li>\n\n\n\n<li>HOME\uff1a\u5f53\u524d\u7528\u6237\u4e3b\u76ee\u5f55\u7684\u8def\u5f84<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>\u91cd\u5b9a\u5411 \u6982\u5ff5\uff1a\u5728 Linux\u7cfb\u7edf\u4e2d\uff0c\u91cd\u5b9a\u5411\u662f\u5c06\u547d\u4ee4\u7684\u8f93\u5165\u6216\u8f93\u51fa\u4ece\u9ed8\u8ba4\u7684\u7ec8\u7aef\u8bbe\u5907\uff08\u5982\u5c4f\u5e55\uff09\u91cd\u5b9a\u5411\u5230\u5176\u4ed6\u4f4d\u7f6e\uff08\u5982\u6587 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2,10],"tags":[21,25,26],"class_list":{"0":"post-341","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"hentry","6":"category-linux","8":"tag-linux","9":"tag-25","10":"tag-26"},"_links":{"self":[{"href":"https:\/\/guapicoding.com\/index.php?rest_route=\/wp\/v2\/posts\/341","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/guapicoding.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/guapicoding.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/guapicoding.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/guapicoding.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=341"}],"version-history":[{"count":46,"href":"https:\/\/guapicoding.com\/index.php?rest_route=\/wp\/v2\/posts\/341\/revisions"}],"predecessor-version":[{"id":914,"href":"https:\/\/guapicoding.com\/index.php?rest_route=\/wp\/v2\/posts\/341\/revisions\/914"}],"wp:attachment":[{"href":"https:\/\/guapicoding.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=341"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/guapicoding.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=341"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/guapicoding.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=341"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}