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Visit website Recent posts Updated on $DATE date linux shaozk - linux Zola2026-08-10T00:00:00+00:00https://shaozk.xyz/tags/linux/atom.xml mktime.c 计算 UNIX 时间戳 2026-08-10T00:00:00+00:00 2026-08-10T00:00:00+00:00 shaozk https://shaozk.xyz/blog/019-mktime-calc-unix-timestamp/ <p>最近尝试阅读 Linux-0.12 源码，让 AI 帮我挑选一个简单的给我，于是有了本文的内容。</p> <p>在正式介绍之前，有个背景知识需要补充：Linux 使用 1970 年 1 月 1 日作为纪元时间，UNIX 时间戳指的是从这天开始到当前时间的间隔秒数。1970 年 1 月 1 日差不多就是 UNIX 诞生的时间。</p> <p><code>mktime.c</code> 中仅仅只有一个函数 <code>kernel_mktime()</code>，目的是将时间结构体 <code>struct tm</code> 转换为 UNIX 时间戳。</p> <p>代码首先定义了年、日、时、分四个宏，用于将其直接转换称对应秒。</p> <pre class="giallo z-code"><code data-lang="c"><span class="giallo-l"><span class="z-punctuation z-definition z-directive z-keyword z-control z-directive">#define</span><span class="z-entity z-name z-function"> MINUTE</span><span class="z-constant z-numeric"> 60</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-directive z-keyword z-control z-directive">#define</span><span class="z-entity z-name z-function"> HOUR</span><span class="z-punctuation"> (</span><span class="z-constant z-numeric">60</span><span class="z-keyword z-operator">*</span><span class="z-source">MINUTE</span><span class="z-punctuation">)</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-directive z-keyword z-control z-directive">#define</span><span class="z-entity z-name z-function"> DAY</span><span class="z-punctuation"> (</span><span class="z-constant z-numeric">24</span><span class="z-keyword z-operator">*</span><span class="z-source">HOUR</span><span class="z-punctuation">)</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-directive z-keyword z-control z-directive">#define</span><span class="z-entity z-name z-function"> YEAR</span><span class="z-punctuation"> (</span><span class="z-constant z-numeric">365</span><span class="z-keyword z-operator">*</span><span class="z-source">DAY</span><span class="z-punctuation">)</span></span></code></pre> <p>这里没有关于月的宏，因为一个月的天数是不定的。这里使用一个长度为 12 的数组，一个元素代表抵达到这个月的时间，并假定为闰年（2 月有 29 天）。</p> <pre class="giallo z-code"><code data-lang="c"><span class="giallo-l"><span class="z-punctuation z-definition z-comment z-comment">/* interestingly, we assume leap-years */</span></span> <span class="giallo-l"><span class="z-storage z-modifier z-storage z-type">static int</span><span class="z-source"> month</span><span class="z-punctuation">[</span><span class="z-constant z-numeric">12</span><span class="z-punctuation">]</span><span class="z-keyword z-operator"> =</span><span class="z-punctuation"> {</span></span> <span class="giallo-l"><span class="z-constant z-numeric"> 0</span><span class="z-punctuation">,</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-punctuation">)</span></span> <span class="giallo-l"><span class="z-punctuation">};</span></span></code></pre> <p>具体转换方法：</p> <ol> <li> <p>年转换为秒</p> <p>除了年份减去 70 之外，还需要判断当年距 1970 年之间出现了几次闰年，并补上额外的天数。</p> <p>这里有一个很巧妙的方法：(year+1)/4：从 1970 年开始，到 1972 为第一个闰年，但是此时是无需额外补充闰日的，要到 1973 年也就是 (3+1)/4 = 1 才补充一天闰日。</p> <p>注：这里并没有考虑 2000 年及以后的情况。</p> </li> <li> <p>月转换为秒</p> <p>查预先设置好的月份表，因为提前假定是闰年，所以当是平年且月份大于1时，需要额外减去一天时间。</p> </li> <li> <p>日转换为秒</p> <p>因为 tm_mday 取值范围时 1-31，因此在转换时需要减去 1 天（当天还没过去）。</p> <pre class="giallo z-code"><code data-lang="c"><span class="giallo-l"><span class="z-storage z-type">struct</span><span class="z-source"> tm </span><span class="z-punctuation">{</span></span> <span class="giallo-l"><span class="z-storage z-type"> int</span><span class="z-source"> tm_sec</span><span class="z-punctuation">;</span><span class="z-punctuation z-definition z-comment z-comment"> /* seconds after the minute [0-60] */</span></span> <span class="giallo-l"><span class="z-storage z-type"> int</span><span class="z-source"> tm_min</span><span class="z-punctuation">;</span><span class="z-punctuation z-definition z-comment z-comment"> /* minutes after the hour [0-59] */</span></span> <span class="giallo-l"><span class="z-storage z-type"> int</span><span class="z-source"> tm_hour</span><span class="z-punctuation">;</span><span class="z-punctuation z-definition z-comment z-comment"> /* hours since midnight [0-23] */</span></span> <span class="giallo-l"><span class="z-storage z-type"> int</span><span class="z-source"> tm_mday</span><span class="z-punctuation">;</span><span class="z-punctuation z-definition z-comment z-comment"> /* day of the month [1-31] */</span></span> <span class="giallo-l"><span class="z-storage z-type"> int</span><span class="z-source"> tm_mon</span><span class="z-punctuation">;</span><span class="z-punctuation z-definition z-comment z-comment"> /* months since January [0-11] */</span></span> <span class="giallo-l"><span class="z-storage z-type"> int</span><span class="z-source"> tm_year</span><span class="z-punctuation">;</span><span class="z-punctuation z-definition z-comment z-comment"> /* years since 1900 */</span></span> <span class="giallo-l"><span class="z-storage z-type"> int</span><span class="z-source"> tm_wday</span><span class="z-punctuation">;</span><span class="z-punctuation z-definition z-comment z-comment"> /* days since Sunday [0-6] */</span></span> <span class="giallo-l"><span class="z-storage z-type"> int</span><span class="z-source"> tm_yday</span><span class="z-punctuation">;</span><span class="z-punctuation z-definition z-comment z-comment"> /* days since January 1 [0-365] */</span></span> <span class="giallo-l"><span class="z-storage z-type"> int</span><span class="z-source"> tm_isdst</span><span class="z-punctuation">;</span><span class="z-punctuation z-definition z-comment z-comment"> /* Daylight Savings Time flag */</span></span> <span class="giallo-l"><span class="z-storage z-type"> long</span><span class="z-source"> tm_gmtoff</span><span class="z-punctuation">;</span><span class="z-punctuation z-definition z-comment z-comment"> /* offset from UTC in seconds */</span></span> <span class="giallo-l"><span class="z-storage z-type"> char</span><span class="z-keyword z-operator"> *</span><span class="z-source">tm_zone</span><span class="z-punctuation">;</span><span class="z-punctuation z-definition z-comment z-comment"> /* timezone abbreviation */</span></span> <span class="giallo-l"><span class="z-punctuation">};</span></span> <span class="giallo-l"></span></code></pre></li> <li> <p>时、分、秒转换为秒</p> <p>直接按照对应宏进行转换。</p> </li> </ol> <p>源码很短，将其全部贴在这里：</p> <pre class="giallo z-code"><code data-lang="c"><span class="giallo-l"><span class="z-punctuation z-definition z-comment">/*</span></span> <span class="giallo-l"><span class="z-comment"> * linux/kernel/mktime.c</span></span> <span class="giallo-l"><span class="z-comment"> *</span></span> <span class="giallo-l"><span class="z-comment"> * (C) 1991 Linus Torvalds</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-comment"> */</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span class="z-punctuation z-definition z-directive z-keyword z-control z-directive">#include</span><span class="z-punctuation z-definition z-string z-string"> &lt;time.h&gt;</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span class="z-punctuation z-definition z-comment">/*</span></span> <span class="giallo-l"><span class="z-comment"> * This isn&#39;t the library routine, it is only used in the kernel.</span></span> <span class="giallo-l"><span class="z-comment"> * as such, we don&#39;t care about years&lt;1970 etc, but assume everything</span></span> <span class="giallo-l"><span class="z-comment"> * is ok. Similarly, TZ etc is happily ignored. We just do everything</span></span> <span class="giallo-l"><span class="z-comment"> * as easily as possible. Let&#39;s find something public for the library</span></span> <span class="giallo-l"><span class="z-comment"> * routines (although I think minix times is public).</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-comment"> */</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-comment">/*</span></span> <span class="giallo-l"><span class="z-comment"> * PS. I hate whoever though up the year 1970 - couldn&#39;t they have gotten</span></span> <span class="giallo-l"><span class="z-comment"> * a leap-year instead? I also hate Gregorius, pope or no. I&#39;m grumpy.</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-comment"> */</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-directive z-keyword z-control z-directive">#define</span><span class="z-entity z-name z-function"> MINUTE</span><span class="z-constant z-numeric"> 60</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-directive z-keyword z-control z-directive">#define</span><span class="z-entity z-name z-function"> HOUR</span><span class="z-punctuation"> (</span><span class="z-constant z-numeric">60</span><span class="z-keyword z-operator">*</span><span class="z-source">MINUTE</span><span class="z-punctuation">)</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-directive z-keyword z-control z-directive">#define</span><span class="z-entity z-name z-function"> DAY</span><span class="z-punctuation"> (</span><span class="z-constant z-numeric">24</span><span class="z-keyword z-operator">*</span><span class="z-source">HOUR</span><span class="z-punctuation">)</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-directive z-keyword z-control z-directive">#define</span><span class="z-entity z-name z-function"> YEAR</span><span class="z-punctuation"> (</span><span class="z-constant z-numeric">365</span><span class="z-keyword z-operator">*</span><span class="z-source">DAY</span><span class="z-punctuation">)</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span class="z-punctuation z-definition z-comment z-comment">/* interestingly, we assume leap-years */</span></span> <span class="giallo-l"><span class="z-storage z-modifier z-storage z-type">static int</span><span class="z-source"> month</span><span class="z-punctuation">[</span><span class="z-constant z-numeric">12</span><span class="z-punctuation">]</span><span class="z-keyword z-operator"> =</span><span class="z-punctuation"> {</span></span> <span class="giallo-l"><span class="z-constant z-numeric"> 0</span><span class="z-punctuation">,</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-punctuation">),</span></span> <span class="giallo-l"><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">29</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">31</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">30</span><span class="z-punctuation">)</span></span> <span class="giallo-l"><span class="z-punctuation">};</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span class="z-storage z-type">long</span><span class="z-entity z-name z-function"> kernel_mktime</span><span class="z-punctuation">(</span><span class="z-storage z-type">struct</span><span class="z-source"> tm </span><span class="z-keyword z-operator">*</span><span class="z-variable z-parameter"> tm</span><span class="z-punctuation">)</span></span> <span class="giallo-l"><span class="z-punctuation">{</span></span> <span class="giallo-l"><span class="z-storage z-type"> long</span><span class="z-source"> res</span><span class="z-punctuation">;</span></span> <span class="giallo-l"><span class="z-storage z-type"> int</span><span class="z-source"> year</span><span class="z-punctuation">;</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span class="z-source"> year </span><span class="z-keyword z-operator">=</span><span class="z-source"> tm</span><span class="z-punctuation">-&gt;</span><span class="z-source">tm_year</span><span class="z-keyword z-operator"> -</span><span class="z-constant z-numeric"> 70</span><span class="z-punctuation">;</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-comment z-comment">/* magic offsets (y+1) needed to get leapyears right.*/</span></span> <span class="giallo-l"><span class="z-source"> res </span><span class="z-keyword z-operator">=</span><span class="z-source"> YEAR</span><span class="z-keyword z-operator">*</span><span class="z-source">year </span><span class="z-keyword z-operator">+</span><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">((</span><span class="z-source">year</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">1</span><span class="z-punctuation">)</span><span class="z-keyword z-operator">/</span><span class="z-constant z-numeric">4</span><span class="z-punctuation">);</span></span> <span class="giallo-l"><span class="z-source"> res </span><span class="z-keyword z-operator">+=</span><span class="z-source"> month</span><span class="z-punctuation">[</span><span class="z-source">tm</span><span class="z-punctuation">-&gt;</span><span class="z-source">tm_mon</span><span class="z-punctuation">];</span></span> <span class="giallo-l"><span class="z-punctuation z-definition z-comment z-comment">/* and (y+2) here. If it wasn&#39;t a leap-year, we have to adjust */</span></span> <span class="giallo-l"><span class="z-keyword"> if</span><span class="z-punctuation"> (</span><span class="z-source">tm</span><span class="z-punctuation">-&gt;</span><span class="z-source">tm_mon</span><span class="z-keyword z-operator">&gt;</span><span class="z-constant z-numeric">1</span><span class="z-keyword z-operator"> &amp;&amp;</span><span class="z-punctuation"> ((</span><span class="z-source">year</span><span class="z-keyword z-operator">+</span><span class="z-constant z-numeric">2</span><span class="z-punctuation">)</span><span class="z-keyword z-operator">%</span><span class="z-constant z-numeric">4</span><span class="z-punctuation">))</span></span> <span class="giallo-l"><span class="z-source"> res </span><span class="z-keyword z-operator">-=</span><span class="z-source"> DAY</span><span class="z-punctuation">;</span></span> <span class="giallo-l"><span class="z-source"> res </span><span class="z-keyword z-operator">+=</span><span class="z-source"> DAY</span><span class="z-keyword z-operator">*</span><span class="z-punctuation">(</span><span class="z-source">tm</span><span class="z-punctuation">-&gt;</span><span class="z-source">tm_mday</span><span class="z-keyword z-operator">-</span><span class="z-constant z-numeric">1</span><span class="z-punctuation">);</span></span> <span class="giallo-l"><span class="z-source"> res </span><span class="z-keyword z-operator">+=</span><span class="z-source"> HOUR</span><span class="z-keyword z-operator">*</span><span class="z-source">tm</span><span class="z-punctuation">-&gt;</span><span class="z-source">tm_hour</span><span class="z-punctuation">;</span></span> <span class="giallo-l"><span class="z-source"> res </span><span class="z-keyword z-operator">+=</span><span class="z-source"> MINUTE</span><span class="z-keyword z-operator">*</span><span class="z-source">tm</span><span class="z-punctuation">-&gt;</span><span class="z-source">tm_min</span><span class="z-punctuation">;</span></span> <span class="giallo-l"><span class="z-source"> res </span><span class="z-keyword z-operator">+=</span><span class="z-source"> tm</span><span class="z-punctuation">-&gt;</span><span class="z-source">tm_sec</span><span class="z-punctuation">;</span></span> <span class="giallo-l"><span class="z-keyword"> return</span><span class="z-source"> res</span><span class="z-punctuation">;</span></span> <span class="giallo-l"><span class="z-punctuation">}</span></span> <span class="giallo-l"></span></code></pre> <p>一个比较有趣的彩蛋是：Linus 在注释中说自己讨厌 1970 并吐槽为什么不直接用闰年作为起始年。</p> 阅读《只是为了好玩》 2026-06-28T00:00:00+00:00 2026-06-28T00:00:00+00:00 shaozk https://shaozk.xyz/blog/002-read-just-for-fun/ <p>读过很多书，但内容到嘴边，硬是说不出。记忆模糊错乱，我想这是不总结的后果吧。</p> <p>一直想总结下阅读感悟，但从未开始过，嗯……就从今天开始吧！</p> <blockquote> <p>小时候的林纳斯就对计算机有极高的兴趣，坐在外公的膝盖帮忙输入程序、研究使用手册并开始编程。</p> </blockquote> <p>回想自己小时候，第一次见到计算机应该是在表哥家的书房，具体记不清几岁了。表哥当时在玩《跑跑卡丁车》，我一下子被吸引住了，那酷炫的卡通人物、刺激的赛车场景、流畅的动画效果，我的天啊！这比手机上的贪吃蛇酷多了。</p> <p>所以，表哥是我获取游戏信息的来源，我几乎在表哥家见证了流行游戏的变化:《赛尔号》、《摩尔庄园》、《弹弹堂》、《穿越火线》。表哥用过的 ID 号 55555 我至今还记得。</p> <p>不过这些都没怎么玩过，我玩过的第一个计算机游戏应该是 4399 小游戏《Q版泡泡堂》，当然是表哥带我玩的。里面有双人模式，连同我姐三人轮流玩，津津有味。</p> <p>这是我对于计算机最初的印象了，当时还是叫它电脑呢……</p> <p>不过对于农村出生的我来说，去表哥家玩游戏已经是接触计算机的全部了。大人们只会给你灌输电脑是毒物的思想，去网吧==坏学生，上网打游戏就是吸食电子毒品。也就是说：去网吧上网是被绝对禁止的，我也确实是 到了大学才开始学习到计算机的知识。</p> <p>但是现在回想一下，当时去网吧的人基本是都是去玩游戏的，会编程的人那时候不会出现在我们乡下的网吧。正如林纳斯所说，现在的孩子把更多的时间花在了玩游戏上，并且沉迷其中:)</p> <blockquote> <p>林纳斯在读大学的时候花了一个暑假把《操作系统：设计与实现》读了很多遍，脱胎换骨，达到了一个全新的高度。</p> </blockquote> <p>自己买了那么多技术书，却从来没有专注读完一本过，有些甚至只读了第一章:(。这么多年学了很多但都不精通，反倒不如把一本书吃透。</p> <p>是时候尝试专心读一本书了。</p> <blockquote> <p>林纳斯最开始只是想在自己的电脑上装一个 Minix 版本的 Unix 系统，但是它的终端却不好用，于是他并开始编写自己 的终端仿真程序，用来登陆学校的计算机看新闻。 为了能够下载和上传文件，又需要编写磁盘驱动。慢慢的功能越来多 ，只要再加把劲，它就能破茧成蝶，变成操作系统了。Linux 诞生了！</p> </blockquote> <p>Linux 项目最开始仅仅是一个终端仿真程序，Unix 项目最开始是丹尼斯和肯想在 PDP-11 计算机上玩《星球大战》。伟大的项目何其相似！</p> <p>兴趣是推动学习进步的好东西，我对计算机的兴趣却似乎越来越少。很糟糕，这样真的很糟糕，我自己还没写多少行代码，就要开始不写代码了（LLM 生成）。</p> <p>网上戏说手写代码是古法编程，但是我还是一个初级程序员，没有得到手搓代码的锻炼呀！我得尝试找找对编程的热爱了。</p> <p>我在网上找到了书中提到的那封开始的邮件原文，CMU 对此进行了维护：http://www.cs.cmu.edu/~awb/linux.history.html</p> <pre class="giallo z-code"><code data-lang="plain"><span class="giallo-l"><span> From: torvalds@klaava.Helsinki.FI (Linus Benedict Torvalds)</span></span> <span class="giallo-l"><span> Newsgroups: comp.os.minix</span></span> <span class="giallo-l"><span> Subject: Gcc-1.40 and a posix-question</span></span> <span class="giallo-l"><span> Message-ID:</span></span> <span class="giallo-l"><span> Date: 3 Jul 91 10:00:50 GMT</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span> Hello netlanders,</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span> Due to a project I&#39;m working on (in minix), I&#39;m interested in the posix</span></span> <span class="giallo-l"><span> standard definition. Could somebody please point me to a (preferably)</span></span> <span class="giallo-l"><span> machine-readable format of the latest posix rules? Ftp-sites would be</span></span> <span class="giallo-l"><span> nice.</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span> The project was obviously linux, so by July 3rd I had started to think</span></span> <span class="giallo-l"><span> about actual user-level things: some of the device drivers were ready,</span></span> <span class="giallo-l"><span> and the harddisk actually worked. Not too much else.</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span> As an aside for all using gcc on minix - [ deleted ]</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span> Just a success-report on porting gcc-1.40 to minix using the 1.37</span></span> <span class="giallo-l"><span> version made by Alan W Black &amp; co.</span></span> <span class="giallo-l"></span> <span class="giallo-l"><span> Linus Torvalds torvalds@kruuna.helsinki.fi </span></span></code></pre> <p>林纳斯一生对编程充满热爱，希望我也能成为这样的一个人吧！</p>