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</pre><pre class="rust ">
<span class="comment">// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT</span>
<span class="comment">// file at the top-level directory of this distribution and at</span>
<span class="comment">// http://rust-lang.org/COPYRIGHT.</span>
<span class="comment">//</span>
<span class="comment">// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or</span>
<span class="comment">// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license</span>
<span class="comment">// <LICENSE-MIT or http://opensource.org/licenses/MIT>, 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="kw">use</span> <span class="ident">io</span>::{<span class="self">self</span>, <span class="ident">Error</span>, <span class="ident">ErrorKind</span>};
<span class="kw">use</span> <span class="ident">libc</span>::{<span class="self">self</span>, <span class="ident">c_int</span>, <span class="ident">gid_t</span>, <span class="ident">pid_t</span>, <span class="ident">uid_t</span>};
<span class="kw">use</span> <span class="ident">mem</span>;
<span class="kw">use</span> <span class="ident">ptr</span>;
<span class="kw">use</span> <span class="ident">sys</span>::<span class="ident">cvt</span>;
<span class="kw">use</span> <span class="ident">sys</span>::<span class="ident">process</span>::<span class="ident">process_common</span>::<span class="kw-2">*</span>;
<span class="comment">////////////////////////////////////////////////////////////////////////////////</span>
<span class="comment">// Command</span>
<span class="comment">////////////////////////////////////////////////////////////////////////////////</span>
<span class="kw">impl</span> <span class="ident">Command</span> {
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">spawn</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">default</span>: <span class="ident">Stdio</span>, <span class="ident">needs_stdin</span>: <span class="ident">bool</span>)
<span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>(<span class="ident">Process</span>, <span class="ident">StdioPipes</span>)<span class="op">></span> {
<span class="kw">use</span> <span class="ident">sys</span>;
<span class="kw">const</span> <span class="ident">CLOEXEC_MSG_FOOTER</span>: <span class="kw-2">&</span><span class="lifetime">'static</span> [<span class="ident">u8</span>] <span class="op">=</span> <span class="string">b"NOEX"</span>;
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">saw_nul</span>() {
<span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">io</span>::<span class="ident">Error</span>::<span class="ident">new</span>(<span class="ident">ErrorKind</span>::<span class="ident">InvalidInput</span>,
<span class="string">"nul byte found in provided data"</span>));
}
<span class="kw">let</span> (<span class="ident">ours</span>, <span class="ident">theirs</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">setup_io</span>(<span class="ident">default</span>, <span class="ident">needs_stdin</span>)<span class="question-mark">?</span>;
<span class="kw">let</span> (<span class="ident">input</span>, <span class="ident">output</span>) <span class="op">=</span> <span class="ident">sys</span>::<span class="ident">pipe</span>::<span class="ident">anon_pipe</span>()<span class="question-mark">?</span>;
<span class="kw">let</span> <span class="ident">pid</span> <span class="op">=</span> <span class="kw">unsafe</span> {
<span class="kw">match</span> <span class="ident">cvt</span>(<span class="ident">libc</span>::<span class="ident">fork</span>())<span class="question-mark">?</span> {
<span class="number">0</span> <span class="op">=></span> {
<span class="ident">drop</span>(<span class="ident">input</span>);
<span class="kw">let</span> <span class="ident">err</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">do_exec</span>(<span class="ident">theirs</span>);
<span class="kw">let</span> <span class="ident">errno</span> <span class="op">=</span> <span class="ident">err</span>.<span class="ident">raw_os_error</span>().<span class="ident">unwrap_or</span>(<span class="ident">libc</span>::<span class="ident">EINVAL</span>) <span class="kw">as</span> <span class="ident">u32</span>;
<span class="kw">let</span> <span class="ident">bytes</span> <span class="op">=</span> [
(<span class="ident">errno</span> <span class="op">>></span> <span class="number">24</span>) <span class="kw">as</span> <span class="ident">u8</span>,
(<span class="ident">errno</span> <span class="op">>></span> <span class="number">16</span>) <span class="kw">as</span> <span class="ident">u8</span>,
(<span class="ident">errno</span> <span class="op">>></span> <span class="number">8</span>) <span class="kw">as</span> <span class="ident">u8</span>,
(<span class="ident">errno</span> <span class="op">>></span> <span class="number">0</span>) <span class="kw">as</span> <span class="ident">u8</span>,
<span class="ident">CLOEXEC_MSG_FOOTER</span>[<span class="number">0</span>], <span class="ident">CLOEXEC_MSG_FOOTER</span>[<span class="number">1</span>],
<span class="ident">CLOEXEC_MSG_FOOTER</span>[<span class="number">2</span>], <span class="ident">CLOEXEC_MSG_FOOTER</span>[<span class="number">3</span>]
];
<span class="comment">// pipe I/O up to PIPE_BUF bytes should be atomic, and then</span>
<span class="comment">// we want to be sure we *don't* run at_exit destructors as</span>
<span class="comment">// we're being torn down regardless</span>
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">output</span>.<span class="ident">write</span>(<span class="kw-2">&</span><span class="ident">bytes</span>).<span class="ident">is_ok</span>());
<span class="ident">libc</span>::<span class="ident">_exit</span>(<span class="number">1</span>)
}
<span class="ident">n</span> <span class="op">=></span> <span class="ident">n</span>,
}
};
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">p</span> <span class="op">=</span> <span class="ident">Process</span> { <span class="ident">pid</span>: <span class="ident">pid</span>, <span class="ident">status</span>: <span class="prelude-val">None</span> };
<span class="ident">drop</span>(<span class="ident">output</span>);
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">bytes</span> <span class="op">=</span> [<span class="number">0</span>; <span class="number">8</span>];
<span class="comment">// loop to handle EINTR</span>
<span class="kw">loop</span> {
<span class="kw">match</span> <span class="ident">input</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">bytes</span>) {
<span class="prelude-val">Ok</span>(<span class="number">0</span>) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Ok</span>((<span class="ident">p</span>, <span class="ident">ours</span>)),
<span class="prelude-val">Ok</span>(<span class="number">8</span>) <span class="op">=></span> {
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">combine</span>(<span class="ident">CLOEXEC_MSG_FOOTER</span>) <span class="op">==</span> <span class="ident">combine</span>(<span class="kw-2">&</span><span class="ident">bytes</span>[<span class="number">4</span>.. <span class="number">8</span>]),
<span class="string">"Validation on the CLOEXEC pipe failed: {:?}"</span>, <span class="ident">bytes</span>);
<span class="kw">let</span> <span class="ident">errno</span> <span class="op">=</span> <span class="ident">combine</span>(<span class="kw-2">&</span><span class="ident">bytes</span>[<span class="number">0</span>.. <span class="number">4</span>]);
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">p</span>.<span class="ident">wait</span>().<span class="ident">is_ok</span>(),
<span class="string">"wait() should either return Ok or panic"</span>);
<span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">Error</span>::<span class="ident">from_raw_os_error</span>(<span class="ident">errno</span>))
}
<span class="prelude-val">Err</span>(<span class="kw-2">ref</span> <span class="ident">e</span>) <span class="kw">if</span> <span class="ident">e</span>.<span class="ident">kind</span>() <span class="op">==</span> <span class="ident">ErrorKind</span>::<span class="ident">Interrupted</span> <span class="op">=></span> {}
<span class="prelude-val">Err</span>(<span class="ident">e</span>) <span class="op">=></span> {
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">p</span>.<span class="ident">wait</span>().<span class="ident">is_ok</span>(),
<span class="string">"wait() should either return Ok or panic"</span>);
<span class="macro">panic</span><span class="macro">!</span>(<span class="string">"the CLOEXEC pipe failed: {:?}"</span>, <span class="ident">e</span>)
},
<span class="prelude-val">Ok</span>(..) <span class="op">=></span> { <span class="comment">// pipe I/O up to PIPE_BUF bytes should be atomic</span>
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">p</span>.<span class="ident">wait</span>().<span class="ident">is_ok</span>(),
<span class="string">"wait() should either return Ok or panic"</span>);
<span class="macro">panic</span><span class="macro">!</span>(<span class="string">"short read on the CLOEXEC pipe"</span>)
}
}
}
<span class="kw">fn</span> <span class="ident">combine</span>(<span class="ident">arr</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">i32</span> {
<span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="ident">arr</span>[<span class="number">0</span>] <span class="kw">as</span> <span class="ident">u32</span>;
<span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="ident">arr</span>[<span class="number">1</span>] <span class="kw">as</span> <span class="ident">u32</span>;
<span class="kw">let</span> <span class="ident">c</span> <span class="op">=</span> <span class="ident">arr</span>[<span class="number">2</span>] <span class="kw">as</span> <span class="ident">u32</span>;
<span class="kw">let</span> <span class="ident">d</span> <span class="op">=</span> <span class="ident">arr</span>[<span class="number">3</span>] <span class="kw">as</span> <span class="ident">u32</span>;
((<span class="ident">a</span> <span class="op"><<</span> <span class="number">24</span>) <span class="op">|</span> (<span class="ident">b</span> <span class="op"><<</span> <span class="number">16</span>) <span class="op">|</span> (<span class="ident">c</span> <span class="op"><<</span> <span class="number">8</span>) <span class="op">|</span> (<span class="ident">d</span> <span class="op"><<</span> <span class="number">0</span>)) <span class="kw">as</span> <span class="ident">i32</span>
}
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">exec</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">default</span>: <span class="ident">Stdio</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="ident">Error</span> {
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">saw_nul</span>() {
<span class="kw">return</span> <span class="ident">io</span>::<span class="ident">Error</span>::<span class="ident">new</span>(<span class="ident">ErrorKind</span>::<span class="ident">InvalidInput</span>,
<span class="string">"nul byte found in provided data"</span>)
}
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">setup_io</span>(<span class="ident">default</span>, <span class="bool-val">true</span>) {
<span class="prelude-val">Ok</span>((_, <span class="ident">theirs</span>)) <span class="op">=></span> <span class="kw">unsafe</span> { <span class="self">self</span>.<span class="ident">do_exec</span>(<span class="ident">theirs</span>) },
<span class="prelude-val">Err</span>(<span class="ident">e</span>) <span class="op">=></span> <span class="ident">e</span>,
}
}
<span class="comment">// And at this point we've reached a special time in the life of the</span>
<span class="comment">// child. The child must now be considered hamstrung and unable to</span>
<span class="comment">// do anything other than syscalls really. Consider the following</span>
<span class="comment">// scenario:</span>
<span class="comment">//</span>
<span class="comment">// 1. Thread A of process 1 grabs the malloc() mutex</span>
<span class="comment">// 2. Thread B of process 1 forks(), creating thread C</span>
<span class="comment">// 3. Thread C of process 2 then attempts to malloc()</span>
<span class="comment">// 4. The memory of process 2 is the same as the memory of</span>
<span class="comment">// process 1, so the mutex is locked.</span>
<span class="comment">//</span>
<span class="comment">// This situation looks a lot like deadlock, right? It turns out</span>
<span class="comment">// that this is what pthread_atfork() takes care of, which is</span>
<span class="comment">// presumably implemented across platforms. The first thing that</span>
<span class="comment">// threads to *before* forking is to do things like grab the malloc</span>
<span class="comment">// mutex, and then after the fork they unlock it.</span>
<span class="comment">//</span>
<span class="comment">// Despite this information, libnative's spawn has been witnessed to</span>
<span class="comment">// deadlock on both macOS and FreeBSD. I'm not entirely sure why, but</span>
<span class="comment">// all collected backtraces point at malloc/free traffic in the</span>
<span class="comment">// child spawned process.</span>
<span class="comment">//</span>
<span class="comment">// For this reason, the block of code below should contain 0</span>
<span class="comment">// invocations of either malloc of free (or their related friends).</span>
<span class="comment">//</span>
<span class="comment">// As an example of not having malloc/free traffic, we don't close</span>
<span class="comment">// this file descriptor by dropping the FileDesc (which contains an</span>
<span class="comment">// allocation). Instead we just close it manually. This will never</span>
<span class="comment">// have the drop glue anyway because this code never returns (the</span>
<span class="comment">// child will either exec() or invoke libc::exit)</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">do_exec</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">stdio</span>: <span class="ident">ChildPipes</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="ident">Error</span> {
<span class="kw">use</span> <span class="ident">sys</span>::{<span class="self">self</span>, <span class="ident">cvt_r</span>};
<span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">t</span> {
(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">e</span>:<span class="ident">expr</span>) <span class="op">=></span> (<span class="kw">match</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">e</span> {
<span class="prelude-val">Ok</span>(<span class="ident">e</span>) <span class="op">=></span> <span class="ident">e</span>,
<span class="prelude-val">Err</span>(<span class="ident">e</span>) <span class="op">=></span> <span class="kw">return</span> <span class="ident">e</span>,
})
}
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">fd</span>) <span class="op">=</span> <span class="ident">stdio</span>.<span class="ident">stdin</span>.<span class="ident">fd</span>() {
<span class="macro">t</span><span class="macro">!</span>(<span class="ident">cvt_r</span>(<span class="op">||</span> <span class="ident">libc</span>::<span class="ident">dup2</span>(<span class="ident">fd</span>, <span class="ident">libc</span>::<span class="ident">STDIN_FILENO</span>)));
}
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">fd</span>) <span class="op">=</span> <span class="ident">stdio</span>.<span class="ident">stdout</span>.<span class="ident">fd</span>() {
<span class="macro">t</span><span class="macro">!</span>(<span class="ident">cvt_r</span>(<span class="op">||</span> <span class="ident">libc</span>::<span class="ident">dup2</span>(<span class="ident">fd</span>, <span class="ident">libc</span>::<span class="ident">STDOUT_FILENO</span>)));
}
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">fd</span>) <span class="op">=</span> <span class="ident">stdio</span>.<span class="ident">stderr</span>.<span class="ident">fd</span>() {
<span class="macro">t</span><span class="macro">!</span>(<span class="ident">cvt_r</span>(<span class="op">||</span> <span class="ident">libc</span>::<span class="ident">dup2</span>(<span class="ident">fd</span>, <span class="ident">libc</span>::<span class="ident">STDERR_FILENO</span>)));
}
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">u</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">get_gid</span>() {
<span class="macro">t</span><span class="macro">!</span>(<span class="ident">cvt</span>(<span class="ident">libc</span>::<span class="ident">setgid</span>(<span class="ident">u</span> <span class="kw">as</span> <span class="ident">gid_t</span>)));
}
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">u</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">get_uid</span>() {
<span class="comment">// When dropping privileges from root, the `setgroups` call</span>
<span class="comment">// will remove any extraneous groups. If we don't call this,</span>
<span class="comment">// then even though our uid has dropped, we may still have</span>
<span class="comment">// groups that enable us to do super-user things. This will</span>
<span class="comment">// fail if we aren't root, so don't bother checking the</span>
<span class="comment">// return value, this is just done as an optimistic</span>
<span class="comment">// privilege dropping function.</span>
<span class="kw">let</span> _ <span class="op">=</span> <span class="ident">libc</span>::<span class="ident">setgroups</span>(<span class="number">0</span>, <span class="ident">ptr</span>::<span class="ident">null</span>());
<span class="macro">t</span><span class="macro">!</span>(<span class="ident">cvt</span>(<span class="ident">libc</span>::<span class="ident">setuid</span>(<span class="ident">u</span> <span class="kw">as</span> <span class="ident">uid_t</span>)));
}
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="kw-2">ref</span> <span class="ident">cwd</span>) <span class="op">=</span> <span class="kw-2">*</span><span class="self">self</span>.<span class="ident">get_cwd</span>() {
<span class="macro">t</span><span class="macro">!</span>(<span class="ident">cvt</span>(<span class="ident">libc</span>::<span class="ident">chdir</span>(<span class="ident">cwd</span>.<span class="ident">as_ptr</span>())));
}
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="kw-2">ref</span> <span class="ident">envp</span>) <span class="op">=</span> <span class="kw-2">*</span><span class="self">self</span>.<span class="ident">get_envp</span>() {
<span class="kw-2">*</span><span class="ident">sys</span>::<span class="ident">os</span>::<span class="ident">environ</span>() <span class="op">=</span> <span class="ident">envp</span>.<span class="ident">as_ptr</span>();
}
<span class="comment">// NaCl has no signal support.</span>
<span class="kw">if</span> <span class="macro">cfg</span><span class="macro">!</span>(<span class="ident">not</span>(<span class="ident">any</span>(<span class="ident">target_os</span> <span class="op">=</span> <span class="string">"nacl"</span>, <span class="ident">target_os</span> <span class="op">=</span> <span class="string">"emscripten"</span>))) {
<span class="comment">// Reset signal handling so the child process starts in a</span>
<span class="comment">// standardized state. libstd ignores SIGPIPE, and signal-handling</span>
<span class="comment">// libraries often set a mask. Child processes inherit ignored</span>
<span class="comment">// signals and the signal mask from their parent, but most</span>
<span class="comment">// UNIX programs do not reset these things on their own, so we</span>
<span class="comment">// need to clean things up now to avoid confusing the program</span>
<span class="comment">// we're about to run.</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">set</span>: <span class="ident">libc</span>::<span class="ident">sigset_t</span> <span class="op">=</span> <span class="ident">mem</span>::<span class="ident">uninitialized</span>();
<span class="kw">if</span> <span class="macro">cfg</span><span class="macro">!</span>(<span class="ident">target_os</span> <span class="op">=</span> <span class="string">"android"</span>) {
<span class="comment">// Implementing sigemptyset allow us to support older Android</span>
<span class="comment">// versions. See the comment about Android and sig* functions in</span>
<span class="comment">// process_common.rs</span>
<span class="ident">libc</span>::<span class="ident">memset</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">set</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw-2">mut</span> _ <span class="kw">as</span> <span class="kw-2">*</span><span class="kw-2">mut</span> _,
<span class="number">0</span>,
<span class="ident">mem</span>::<span class="ident">size_of</span>::<span class="op"><</span><span class="ident">libc</span>::<span class="ident">sigset_t</span><span class="op">></span>());
} <span class="kw">else</span> {
<span class="macro">t</span><span class="macro">!</span>(<span class="ident">cvt</span>(<span class="ident">libc</span>::<span class="ident">sigemptyset</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">set</span>)));
}
<span class="macro">t</span><span class="macro">!</span>(<span class="ident">cvt</span>(<span class="ident">libc</span>::<span class="ident">pthread_sigmask</span>(<span class="ident">libc</span>::<span class="ident">SIG_SETMASK</span>, <span class="kw-2">&</span><span class="ident">set</span>,
<span class="ident">ptr</span>::<span class="ident">null_mut</span>())));
<span class="kw">let</span> <span class="ident">ret</span> <span class="op">=</span> <span class="ident">sys</span>::<span class="ident">signal</span>(<span class="ident">libc</span>::<span class="ident">SIGPIPE</span>, <span class="ident">libc</span>::<span class="ident">SIG_DFL</span>);
<span class="kw">if</span> <span class="ident">ret</span> <span class="op">==</span> <span class="ident">libc</span>::<span class="ident">SIG_ERR</span> {
<span class="kw">return</span> <span class="ident">io</span>::<span class="ident">Error</span>::<span class="ident">last_os_error</span>()
}
}
<span class="kw">for</span> <span class="ident">callback</span> <span class="kw">in</span> <span class="self">self</span>.<span class="ident">get_closures</span>().<span class="ident">iter_mut</span>() {
<span class="macro">t</span><span class="macro">!</span>(<span class="ident">callback</span>());
}
<span class="ident">libc</span>::<span class="ident">execvp</span>(<span class="self">self</span>.<span class="ident">get_argv</span>()[<span class="number">0</span>], <span class="self">self</span>.<span class="ident">get_argv</span>().<span class="ident">as_ptr</span>());
<span class="ident">io</span>::<span class="ident">Error</span>::<span class="ident">last_os_error</span>()
}
}
<span class="comment">////////////////////////////////////////////////////////////////////////////////</span>
<span class="comment">// Processes</span>
<span class="comment">////////////////////////////////////////////////////////////////////////////////</span>
<span class="doccomment">/// The unique id of the process (this should never be negative).</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Process</span> {
<span class="ident">pid</span>: <span class="ident">pid_t</span>,
<span class="ident">status</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">ExitStatus</span><span class="op">></span>,
}
<span class="kw">impl</span> <span class="ident">Process</span> {
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">id</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">u32</span> {
<span class="self">self</span>.<span class="ident">pid</span> <span class="kw">as</span> <span class="ident">u32</span>
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">kill</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> {
<span class="comment">// If we've already waited on this process then the pid can be recycled</span>
<span class="comment">// and used for another process, and we probably shouldn't be killing</span>
<span class="comment">// random processes, so just return an error.</span>
<span class="kw">if</span> <span class="self">self</span>.<span class="ident">status</span>.<span class="ident">is_some</span>() {
<span class="prelude-val">Err</span>(<span class="ident">Error</span>::<span class="ident">new</span>(<span class="ident">ErrorKind</span>::<span class="ident">InvalidInput</span>,
<span class="string">"invalid argument: can't kill an exited process"</span>))
} <span class="kw">else</span> {
<span class="ident">cvt</span>(<span class="kw">unsafe</span> { <span class="ident">libc</span>::<span class="ident">kill</span>(<span class="self">self</span>.<span class="ident">pid</span>, <span class="ident">libc</span>::<span class="ident">SIGKILL</span>) }).<span class="ident">map</span>(<span class="op">|</span>_<span class="op">|</span> ())
}
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">wait</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">ExitStatus</span><span class="op">></span> {
<span class="kw">use</span> <span class="ident">sys</span>::<span class="ident">cvt_r</span>;
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">status</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">status</span> {
<span class="kw">return</span> <span class="prelude-val">Ok</span>(<span class="ident">status</span>)
}
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">status</span> <span class="op">=</span> <span class="number">0</span> <span class="kw">as</span> <span class="ident">c_int</span>;
<span class="ident">cvt_r</span>(<span class="op">||</span> <span class="kw">unsafe</span> { <span class="ident">libc</span>::<span class="ident">waitpid</span>(<span class="self">self</span>.<span class="ident">pid</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">status</span>, <span class="number">0</span>) })<span class="question-mark">?</span>;
<span class="self">self</span>.<span class="ident">status</span> <span class="op">=</span> <span class="prelude-val">Some</span>(<span class="ident">ExitStatus</span>::<span class="ident">new</span>(<span class="ident">status</span>));
<span class="prelude-val">Ok</span>(<span class="ident">ExitStatus</span>::<span class="ident">new</span>(<span class="ident">status</span>))
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">try_wait</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">ExitStatus</span><span class="op">>></span> {
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">status</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">status</span> {
<span class="kw">return</span> <span class="prelude-val">Ok</span>(<span class="prelude-val">Some</span>(<span class="ident">status</span>))
}
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">status</span> <span class="op">=</span> <span class="number">0</span> <span class="kw">as</span> <span class="ident">c_int</span>;
<span class="kw">let</span> <span class="ident">pid</span> <span class="op">=</span> <span class="ident">cvt</span>(<span class="kw">unsafe</span> {
<span class="ident">libc</span>::<span class="ident">waitpid</span>(<span class="self">self</span>.<span class="ident">pid</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">status</span>, <span class="ident">libc</span>::<span class="ident">WNOHANG</span>)
})<span class="question-mark">?</span>;
<span class="kw">if</span> <span class="ident">pid</span> <span class="op">==</span> <span class="number">0</span> {
<span class="prelude-val">Ok</span>(<span class="prelude-val">None</span>)
} <span class="kw">else</span> {
<span class="self">self</span>.<span class="ident">status</span> <span class="op">=</span> <span class="prelude-val">Some</span>(<span class="ident">ExitStatus</span>::<span class="ident">new</span>(<span class="ident">status</span>));
<span class="prelude-val">Ok</span>(<span class="prelude-val">Some</span>(<span class="ident">ExitStatus</span>::<span class="ident">new</span>(<span class="ident">status</span>)))
}
}
}
</pre>
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