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</pre><pre class="rust"><code><span class="comment">// Copyright 2019 Developers of the Rand project.</span>
<span class="comment">//</span>
<span class="comment">// Licensed under the Apache License, Version 2.0 &lt;LICENSE-APACHE or</span>
<span class="comment">// https://www.apache.org/licenses/LICENSE-2.0&gt; or the MIT license</span>
<span class="comment">// &lt;LICENSE-MIT or https://opensource.org/licenses/MIT&gt;, at your</span>
<span class="comment">// option. This file may not be copied, modified, or distributed</span>
<span class="comment">// except according to those terms.</span>
<span class="attribute">#![<span class="ident">allow</span>(<span class="ident">dead_code</span>)]</span>
<span class="kw">use</span> <span class="kw">crate</span>::{<span class="ident">util::LazyUsize</span>, <span class="ident">Error</span>};
<span class="kw">use</span> <span class="ident">core</span>::{<span class="ident">num::NonZeroU32</span>, <span class="ident">ptr::NonNull</span>};
<span class="macro">cfg_if!</span> {
<span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;netbsd&quot;</span>, <span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;openbsd&quot;</span>, <span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;android&quot;</span>))]</span> {
<span class="kw">use</span> <span class="ident">libc::__errno</span> <span class="kw">as</span> <span class="ident">errno_location</span>;
} <span class="kw">else</span> <span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;linux&quot;</span>, <span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;emscripten&quot;</span>, <span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;redox&quot;</span>))]</span> {
<span class="kw">use</span> <span class="ident">libc::__errno_location</span> <span class="kw">as</span> <span class="ident">errno_location</span>;
} <span class="kw">else</span> <span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;solaris&quot;</span>, <span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;illumos&quot;</span>))]</span> {
<span class="kw">use</span> <span class="ident">libc::___errno</span> <span class="kw">as</span> <span class="ident">errno_location</span>;
} <span class="kw">else</span> <span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;macos&quot;</span>, <span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;freebsd&quot;</span>))]</span> {
<span class="kw">use</span> <span class="ident">libc::__error</span> <span class="kw">as</span> <span class="ident">errno_location</span>;
} <span class="kw">else</span> <span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;haiku&quot;</span>)]</span> {
<span class="kw">use</span> <span class="ident">libc::_errnop</span> <span class="kw">as</span> <span class="ident">errno_location</span>;
}
}
<span class="macro">cfg_if!</span> {
<span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;vxworks&quot;</span>)]</span> {
<span class="kw">use</span> <span class="ident">libc::errnoGet</span> <span class="kw">as</span> <span class="ident">get_errno</span>;
} <span class="kw">else</span> <span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;dragonfly&quot;</span>)]</span> {
<span class="comment">// Until rust-lang/rust#29594 is stable, we cannot get the errno value</span>
<span class="comment">// on DragonFlyBSD. So we just return an out-of-range errno.</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">get_errno</span>() -&gt; <span class="ident">libc::c_int</span> { <span class="op">-</span><span class="number">1</span> }
} <span class="kw">else</span> {
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">get_errno</span>() -&gt; <span class="ident">libc::c_int</span> { <span class="kw-2">*</span><span class="ident">errno_location</span>() }
}
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">last_os_error</span>() -&gt; <span class="ident">Error</span> {
<span class="kw">let</span> <span class="ident">errno</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="ident">get_errno</span>() };
<span class="kw">if</span> <span class="ident">errno</span> <span class="op">&gt;</span> <span class="number">0</span> {
<span class="ident">Error::from</span>(<span class="ident">NonZeroU32::new</span>(<span class="ident">errno</span> <span class="kw">as</span> <span class="ident">u32</span>).<span class="ident">unwrap</span>())
} <span class="kw">else</span> {
<span class="ident">Error::ERRNO_NOT_POSITIVE</span>
}
}
<span class="comment">// Fill a buffer by repeatedly invoking a system call. The `sys_fill` function:</span>
<span class="comment">// - should return -1 and set errno on failure</span>
<span class="comment">// - should return the number of bytes written on success</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">sys_fill_exact</span>(
<span class="kw-2">mut</span> <span class="ident">buf</span>: <span class="kw-2">&amp;mut</span> [<span class="ident">u8</span>],
<span class="ident">sys_fill</span>: <span class="kw">impl</span> <span class="ident">Fn</span>(<span class="kw-2">&amp;mut</span> [<span class="ident">u8</span>]) -&gt; <span class="ident">libc::ssize_t</span>,
) -&gt; <span class="prelude-ty">Result</span><span class="op">&lt;</span>(), <span class="ident">Error</span><span class="op">&gt;</span> {
<span class="kw">while</span> <span class="op">!</span><span class="ident">buf</span>.<span class="ident">is_empty</span>() {
<span class="kw">let</span> <span class="ident">res</span> <span class="op">=</span> <span class="ident">sys_fill</span>(<span class="ident">buf</span>);
<span class="kw">if</span> <span class="ident">res</span> <span class="op">&lt;</span> <span class="number">0</span> {
<span class="kw">let</span> <span class="ident">err</span> <span class="op">=</span> <span class="ident">last_os_error</span>();
<span class="comment">// We should try again if the call was interrupted.</span>
<span class="kw">if</span> <span class="ident">err</span>.<span class="ident">raw_os_error</span>() <span class="op">!</span><span class="op">=</span> <span class="prelude-val">Some</span>(<span class="ident">libc::EINTR</span>) {
<span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">err</span>);
}
} <span class="kw">else</span> {
<span class="comment">// We don&#39;t check for EOF (ret = 0) as the data we are reading</span>
<span class="comment">// should be an infinite stream of random bytes.</span>
<span class="ident">buf</span> <span class="op">=</span> <span class="kw-2">&amp;mut</span> <span class="ident">buf</span>[(<span class="ident">res</span> <span class="kw">as</span> <span class="ident">usize</span>)..];
}
}
<span class="prelude-val">Ok</span>(())
}
<span class="comment">// A &quot;weak&quot; binding to a C function that may or may not be present at runtime.</span>
<span class="comment">// Used for supporting newer OS features while still building on older systems.</span>
<span class="comment">// F must be a function pointer of type `unsafe extern &quot;C&quot; fn`. Based off of the</span>
<span class="comment">// weak! macro in libstd.</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Weak</span> {
<span class="ident">name</span>: <span class="kw-2">&amp;</span><span class="lifetime">&#39;static</span> <span class="ident">str</span>,
<span class="ident">addr</span>: <span class="ident">LazyUsize</span>,
}
<span class="kw">impl</span> <span class="ident">Weak</span> {
<span class="comment">// Construct a binding to a C function with a given name. This function is</span>
<span class="comment">// unsafe because `name` _must_ be null terminated.</span>
<span class="kw">pub</span> <span class="kw">const</span> <span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">name</span>: <span class="kw-2">&amp;</span><span class="lifetime">&#39;static</span> <span class="ident">str</span>) -&gt; <span class="self">Self</span> {
<span class="self">Self</span> {
<span class="ident">name</span>,
<span class="ident">addr</span>: <span class="ident">LazyUsize::new</span>(),
}
}
<span class="comment">// Return a function pointer if present at runtime. Otherwise, return null.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">ptr</span>(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; <span class="prelude-ty">Option</span><span class="op">&lt;</span><span class="ident">NonNull</span><span class="op">&lt;</span><span class="ident">libc::c_void</span><span class="op">&gt;</span><span class="op">&gt;</span> {
<span class="kw">let</span> <span class="ident">addr</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">addr</span>.<span class="ident">unsync_init</span>(<span class="op">|</span><span class="op">|</span> <span class="kw">unsafe</span> {
<span class="ident">libc::dlsym</span>(<span class="ident">libc::RTLD_DEFAULT</span>, <span class="self">self</span>.<span class="ident">name</span>.<span class="ident">as_ptr</span>() <span class="kw">as</span> <span class="kw-2">*const</span> <span class="kw">_</span>) <span class="kw">as</span> <span class="ident">usize</span>
});
<span class="ident">NonNull::new</span>(<span class="ident">addr</span> <span class="kw">as</span> <span class="kw-2">*mut</span> <span class="kw">_</span>)
}
}
<span class="macro">cfg_if!</span> {
<span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">any</span>(<span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;linux&quot;</span>, <span class="ident">target_os</span> <span class="op">=</span> <span class="string">&quot;emscripten&quot;</span>))]</span> {
<span class="kw">use</span> <span class="ident">libc::open64</span> <span class="kw">as</span> <span class="ident">open</span>;
} <span class="kw">else</span> {
<span class="kw">use</span> <span class="ident">libc::open</span>;
}
}
<span class="comment">// SAFETY: path must be null terminated, FD must be manually closed.</span>
<span class="kw">pub</span> <span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">open_readonly</span>(<span class="ident">path</span>: <span class="kw-2">&amp;</span><span class="ident">str</span>) -&gt; <span class="prelude-ty">Result</span><span class="op">&lt;</span><span class="ident">libc::c_int</span>, <span class="ident">Error</span><span class="op">&gt;</span> {
<span class="macro">debug_assert_eq!</span>(<span class="ident">path</span>.<span class="ident">as_bytes</span>().<span class="ident">last</span>(), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="number">0</span>));
<span class="kw">let</span> <span class="ident">fd</span> <span class="op">=</span> <span class="ident">open</span>(<span class="ident">path</span>.<span class="ident">as_ptr</span>() <span class="kw">as</span> <span class="kw-2">*const</span> <span class="kw">_</span>, <span class="ident">libc::O_RDONLY</span> <span class="op">|</span> <span class="ident">libc::O_CLOEXEC</span>);
<span class="kw">if</span> <span class="ident">fd</span> <span class="op">&lt;</span> <span class="number">0</span> {
<span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">last_os_error</span>());
}
<span class="prelude-val">Ok</span>(<span class="ident">fd</span>)
}
</code></pre></div>
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