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| <p class='location'>Module ioctl</p><div class="block items"><ul><li><a href="#constants">Constants</a></li><li><a href="#functions">Functions</a></li></ul></div><p class='location'><a href='../../index.html'>nix</a>::<wbr><a href='../index.html'>sys</a></p><script>window.sidebarCurrent = {name: 'ioctl', ty: 'mod', relpath: '../'};</script><script defer src="../sidebar-items.js"></script> |
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| <h1 class='fqn'><span class='in-band'>Module <a href='../../index.html'>nix</a>::<wbr><a href='../index.html'>sys</a>::<wbr><a class="mod" href=''>ioctl</a></span><span class='out-of-band'><span id='render-detail'> |
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| [<span class='inner'>−</span>] |
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| </span><a class='srclink' href='../../../src/nix/sys/ioctl/mod.rs.html#1-198' title='goto source code'>[src]</a></span></h1> |
| <div class='docblock'><p>Provide helpers for making ioctl system calls</p> |
| |
| <p>Currently supports Linux on all architectures. Other platforms welcome!</p> |
| |
| <p>This library is pretty low-level and messy. <code>ioctl</code> is not fun.</p> |
| |
| <h1 id='what-is-an-ioctl' class='section-header'><a href='#what-is-an-ioctl'>What is an <code>ioctl</code>?</a></h1> |
| <p>The <code>ioctl</code> syscall is the grab-bag syscall on POSIX systems. Don't want |
| to add a new syscall? Make it an <code>ioctl</code>! <code>ioctl</code> refers to both the syscall, |
| and the commands that can be send with it. <code>ioctl</code> stands for "IO control", |
| and the commands are always sent to a file descriptor.</p> |
| |
| <p>It is common to see <code>ioctl</code>s used for the following purposes:</p> |
| |
| <ul> |
| <li>Provide read/write access to out-of-band data related |
| to a device such as configuration (for instance, setting |
| serial port options)</li> |
| <li>Provide a mechanism for performing full-duplex data |
| transfers (for instance, xfer on SPI devices).</li> |
| <li>Provide access to control functions on a device (for example, |
| on Linux you can send commands like pause, resume, and eject |
| to the CDROM device.</li> |
| <li>Do whatever else the device driver creator thought made most sense.</li> |
| </ul> |
| |
| <p><code>ioctl</code>s are synchronous system calls and are similar to read and |
| write calls in that regard.</p> |
| |
| <h1 id='what-does-this-module-support' class='section-header'><a href='#what-does-this-module-support'>What does this module support?</a></h1> |
| <p>This library provides the <code>ioctl!</code> macro, for binding <code>ioctl</code>s. |
| Here's a few examples of how that can work for SPI under Linux |
| from <a href="https://github.com/posborne/rust-spidev">rust-spidev</a>.</p> |
| |
| <pre class="rust rust-example-rendered"> |
| <span class="attribute">#[<span class="ident">macro_use</span>]</span> <span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">nix</span>; |
| |
| <span class="attribute">#[<span class="ident">allow</span>(<span class="ident">non_camel_case_types</span>)]</span> |
| <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">spi_ioc_transfer</span> { |
| <span class="kw">pub</span> <span class="ident">tx_buf</span>: <span class="ident">u64</span>, |
| <span class="kw">pub</span> <span class="ident">rx_buf</span>: <span class="ident">u64</span>, |
| <span class="kw">pub</span> <span class="ident">len</span>: <span class="ident">u32</span>, |
| |
| <span class="comment">// optional overrides</span> |
| <span class="kw">pub</span> <span class="ident">speed_hz</span>: <span class="ident">u32</span>, |
| <span class="kw">pub</span> <span class="ident">delay_usecs</span>: <span class="ident">u16</span>, |
| <span class="kw">pub</span> <span class="ident">bits_per_word</span>: <span class="ident">u8</span>, |
| <span class="kw">pub</span> <span class="ident">cs_change</span>: <span class="ident">u8</span>, |
| <span class="kw">pub</span> <span class="ident">pad</span>: <span class="ident">u32</span>, |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">linux</span>)]</span> |
| <span class="kw">mod</span> <span class="ident">ioctl</span> { |
| <span class="kw">use</span> <span class="kw">super</span>::<span class="kw-2">*</span>; |
| |
| <span class="kw">const</span> <span class="ident">SPI_IOC_MAGIC</span>: <span class="ident">u8</span> <span class="op">=</span> <span class="string">'k'</span> <span class="kw">as</span> <span class="ident">u8</span>; |
| <span class="kw">const</span> <span class="ident">SPI_IOC_NR_TRANSFER</span>: <span class="ident">u8</span> <span class="op">=</span> <span class="number">0</span>; |
| <span class="kw">const</span> <span class="ident">SPI_IOC_NR_MODE</span>: <span class="ident">u8</span> <span class="op">=</span> <span class="number">1</span>; |
| <span class="kw">const</span> <span class="ident">SPI_IOC_NR_LSB_FIRST</span>: <span class="ident">u8</span> <span class="op">=</span> <span class="number">2</span>; |
| <span class="kw">const</span> <span class="ident">SPI_IOC_NR_BITS_PER_WORD</span>: <span class="ident">u8</span> <span class="op">=</span> <span class="number">3</span>; |
| <span class="kw">const</span> <span class="ident">SPI_IOC_NR_MAX_SPEED_HZ</span>: <span class="ident">u8</span> <span class="op">=</span> <span class="number">4</span>; |
| <span class="kw">const</span> <span class="ident">SPI_IOC_NR_MODE32</span>: <span class="ident">u8</span> <span class="op">=</span> <span class="number">5</span>; |
| |
| <span class="macro">ioctl</span><span class="macro">!</span>(<span class="ident">read</span> <span class="ident">get_mode_u8</span> <span class="ident">with</span> <span class="ident">SPI_IOC_MAGIC</span>, <span class="ident">SPI_IOC_NR_MODE</span>; <span class="ident">u8</span>); |
| <span class="macro">ioctl</span><span class="macro">!</span>(<span class="ident">read</span> <span class="ident">get_mode_u32</span> <span class="ident">with</span> <span class="ident">SPI_IOC_MAGIC</span>, <span class="ident">SPI_IOC_NR_MODE</span>; <span class="ident">u32</span>); |
| <span class="macro">ioctl</span><span class="macro">!</span>(<span class="ident">write</span> <span class="ident">set_mode_u8</span> <span class="ident">with</span> <span class="ident">SPI_IOC_MAGIC</span>, <span class="ident">SPI_IOC_NR_MODE</span>; <span class="ident">u8</span>); |
| <span class="macro">ioctl</span><span class="macro">!</span>(<span class="ident">write</span> <span class="ident">set_mode_u32</span> <span class="ident">with</span> <span class="ident">SPI_IOC_MAGIC</span>, <span class="ident">SPI_IOC_NR_MODE32</span>; <span class="ident">u32</span>); |
| <span class="macro">ioctl</span><span class="macro">!</span>(<span class="ident">read</span> <span class="ident">get_lsb_first</span> <span class="ident">with</span> <span class="ident">SPI_IOC_MAGIC</span>, <span class="ident">SPI_IOC_NR_LSB_FIRST</span>; <span class="ident">u8</span>); |
| <span class="macro">ioctl</span><span class="macro">!</span>(<span class="ident">write</span> <span class="ident">set_lsb_first</span> <span class="ident">with</span> <span class="ident">SPI_IOC_MAGIC</span>, <span class="ident">SPI_IOC_NR_LSB_FIRST</span>; <span class="ident">u8</span>); |
| <span class="macro">ioctl</span><span class="macro">!</span>(<span class="ident">read</span> <span class="ident">get_bits_per_word</span> <span class="ident">with</span> <span class="ident">SPI_IOC_MAGIC</span>, <span class="ident">SPI_IOC_NR_BITS_PER_WORD</span>; <span class="ident">u8</span>); |
| <span class="macro">ioctl</span><span class="macro">!</span>(<span class="ident">write</span> <span class="ident">set_bits_per_word</span> <span class="ident">with</span> <span class="ident">SPI_IOC_MAGIC</span>, <span class="ident">SPI_IOC_NR_BITS_PER_WORD</span>; <span class="ident">u8</span>); |
| <span class="macro">ioctl</span><span class="macro">!</span>(<span class="ident">read</span> <span class="ident">get_max_speed_hz</span> <span class="ident">with</span> <span class="ident">SPI_IOC_MAGIC</span>, <span class="ident">SPI_IOC_NR_MAX_SPEED_HZ</span>; <span class="ident">u32</span>); |
| <span class="macro">ioctl</span><span class="macro">!</span>(<span class="ident">write</span> <span class="ident">set_max_speed_hz</span> <span class="ident">with</span> <span class="ident">SPI_IOC_MAGIC</span>, <span class="ident">SPI_IOC_NR_MAX_SPEED_HZ</span>; <span class="ident">u32</span>); |
| <span class="macro">ioctl</span><span class="macro">!</span>(<span class="ident">write</span> <span class="ident">spidev_transfer</span> <span class="ident">with</span> <span class="ident">SPI_IOC_MAGIC</span>, <span class="ident">SPI_IOC_NR_TRANSFER</span>; <span class="ident">spi_ioc_transfer</span>); |
| <span class="macro">ioctl</span><span class="macro">!</span>(<span class="ident">write</span> <span class="ident">buf</span> <span class="ident">spidev_transfer_buf</span> <span class="ident">with</span> <span class="ident">SPI_IOC_MAGIC</span>, <span class="ident">SPI_IOC_NR_TRANSFER</span>; <span class="ident">spi_ioc_transfer</span>); |
| } |
| |
| <span class="comment">// doctest workaround</span> |
| <span class="kw">fn</span> <span class="ident">main</span>() {}</pre> |
| |
| <p>Spidev uses the <code>_IOC</code> macros that are encouraged (as far as |
| <code>ioctl</code> can be encouraged at all) for newer drivers. Many |
| drivers, however, just use magic numbers with no attached |
| semantics. For those, the <code>ioctl!(bad ...)</code> variant should be |
| used (the "bad" terminology is from the Linux kernel).</p> |
| |
| <h1 id='how-do-i-get-the-magic-numbers' class='section-header'><a href='#how-do-i-get-the-magic-numbers'>How do I get the magic numbers?</a></h1> |
| <p>For Linux, look at your system's headers. For example, <code>/usr/include/linux/input.h</code> has a lot |
| of lines defining macros which use <code>_IOR</code>, <code>_IOW</code>, <code>_IOC</code>, and <code>_IORW</code>. These macros |
| correspond to the <code>ior!</code>, <code>iow!</code>, <code>ioc!</code>, and <code>iorw!</code> macros defined in this crate. |
| Additionally, there is the <code>ioctl!</code> macro for creating a wrapper around <code>ioctl</code> that is |
| somewhat more type-safe.</p> |
| |
| <p>Most <code>ioctl</code>s have no or little documentation. You'll need to scrounge through |
| the source to figure out what they do and how they should be used.</p> |
| </div><h2 id='constants' class='section-header'><a href="#constants">Constants</a></h2> |
| <table> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.DIRBITS.html" |
| title='constant nix::sys::ioctl::DIRBITS'>DIRBITS</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.DIRMASK.html" |
| title='constant nix::sys::ioctl::DIRMASK'>DIRMASK</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.DIRSHIFT.html" |
| title='constant nix::sys::ioctl::DIRSHIFT'>DIRSHIFT</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.IN.html" |
| title='constant nix::sys::ioctl::IN'>IN</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.INOUT.html" |
| title='constant nix::sys::ioctl::INOUT'>INOUT</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.NONE.html" |
| title='constant nix::sys::ioctl::NONE'>NONE</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.NRBITS.html" |
| title='constant nix::sys::ioctl::NRBITS'>NRBITS</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.NRMASK.html" |
| title='constant nix::sys::ioctl::NRMASK'>NRMASK</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.NRSHIFT.html" |
| title='constant nix::sys::ioctl::NRSHIFT'>NRSHIFT</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.OUT.html" |
| title='constant nix::sys::ioctl::OUT'>OUT</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.READ.html" |
| title='constant nix::sys::ioctl::READ'>READ</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.SIZEBITS.html" |
| title='constant nix::sys::ioctl::SIZEBITS'>SIZEBITS</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.SIZEMASK.html" |
| title='constant nix::sys::ioctl::SIZEMASK'>SIZEMASK</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.SIZESHIFT.html" |
| title='constant nix::sys::ioctl::SIZESHIFT'>SIZESHIFT</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.SIZE_MASK.html" |
| title='constant nix::sys::ioctl::SIZE_MASK'>SIZE_MASK</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.TYPEBITS.html" |
| title='constant nix::sys::ioctl::TYPEBITS'>TYPEBITS</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.TYPEMASK.html" |
| title='constant nix::sys::ioctl::TYPEMASK'>TYPEMASK</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.TYPESHIFT.html" |
| title='constant nix::sys::ioctl::TYPESHIFT'>TYPESHIFT</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="constant" href="constant.WRITE.html" |
| title='constant nix::sys::ioctl::WRITE'>WRITE</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr></table><h2 id='functions' class='section-header'><a href="#functions">Functions</a></h2> |
| <table> |
| <tr class=' module-item'> |
| <td><a class="fn" href="fn.ioc_dir.html" |
| title='fn nix::sys::ioctl::ioc_dir'>ioc_dir</a></td> |
| <td class='docblock-short'> |
| <p>Extracts the "direction" (read/write/none) from an encoded ioctl command.</p> |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="fn" href="fn.ioc_nr.html" |
| title='fn nix::sys::ioctl::ioc_nr'>ioc_nr</a></td> |
| <td class='docblock-short'> |
| <p>Extracts the ioctl number from an encoded ioctl command.</p> |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="fn" href="fn.ioc_size.html" |
| title='fn nix::sys::ioctl::ioc_size'>ioc_size</a></td> |
| <td class='docblock-short'> |
| <p>Extracts the size from an encoded ioctl command.</p> |
| </td> |
| </tr> |
| <tr class=' module-item'> |
| <td><a class="fn" href="fn.ioc_type.html" |
| title='fn nix::sys::ioctl::ioc_type'>ioc_type</a></td> |
| <td class='docblock-short'> |
| <p>Extracts the type from an encoded ioctl command.</p> |
| </td> |
| </tr></table></section> |
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