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diff --git a/linux/input.html b/linux/input.html new file mode 100644 index 0000000..66eba36 --- /dev/null +++ b/linux/input.html @@ -0,0 +1,298 @@ +<!DOCTYPE HTML> +<html lang="en" class="sidebar-visible no-js light"> + <head> + <!-- Book generated using mdBook --> + <meta charset="UTF-8"> + <title>input - Notes</title> + <!-- Custom HTML head --> + <meta content="text/html; charset=utf-8" http-equiv="Content-Type"> + <meta name="description" content=""> + <meta name="viewport" content="width=device-width, initial-scale=1"> + <meta name="theme-color" content="#ffffff" /> + + <link rel="icon" href="../favicon.svg"> + <link rel="shortcut icon" href="../favicon.png"> + <link rel="stylesheet" href="../css/variables.css"> + <link rel="stylesheet" href="../css/general.css"> + <link rel="stylesheet" href="../css/chrome.css"> + <link rel="stylesheet" href="../css/print.css" media="print"> + <!-- Fonts --> + <link rel="stylesheet" href="../FontAwesome/css/font-awesome.css"> + <link rel="stylesheet" href="../fonts/fonts.css"> + <!-- Highlight.js Stylesheets --> + <link rel="stylesheet" href="../highlight.css"> + <link rel="stylesheet" href="../tomorrow-night.css"> + <link rel="stylesheet" href="../ayu-highlight.css"> + + <!-- Custom theme stylesheets --> + </head> + <body> + <!-- Provide site root to javascript --> + <script type="text/javascript"> + var path_to_root = "../"; + var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? 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aria-hidden="true">1.2.</strong> bash</a></li><li class="chapter-item expanded "><a href="../tools/fish.html"><strong aria-hidden="true">1.3.</strong> fish</a></li><li class="chapter-item expanded "><a href="../tools/tmux.html"><strong aria-hidden="true">1.4.</strong> tmux</a></li><li class="chapter-item expanded "><a href="../tools/git.html"><strong aria-hidden="true">1.5.</strong> git</a></li><li class="chapter-item expanded "><a href="../tools/awk.html"><strong aria-hidden="true">1.6.</strong> awk</a></li><li class="chapter-item expanded "><a href="../tools/emacs.html"><strong aria-hidden="true">1.7.</strong> emacs</a></li><li class="chapter-item expanded "><a href="../tools/gpg.html"><strong aria-hidden="true">1.8.</strong> gpg</a></li><li class="chapter-item expanded "><a href="../tools/gdb.html"><strong aria-hidden="true">1.9.</strong> gdb</a></li><li class="chapter-item expanded "><a href="../tools/gdbserver.html"><strong aria-hidden="true">1.10.</strong> gdbserver</a></li><li 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expanded "><a href="../trace_profile/oprofile.html"><strong aria-hidden="true">3.4.</strong> OProfile</a></li><li class="chapter-item expanded "><a href="../trace_profile/time.html"><strong aria-hidden="true">3.5.</strong> time</a></li></ol></li><li class="chapter-item expanded "><a href="../binary/index.html"><strong aria-hidden="true">4.</strong> Binary</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../binary/od.html"><strong aria-hidden="true">4.1.</strong> od</a></li><li class="chapter-item expanded "><a href="../binary/xxd.html"><strong aria-hidden="true">4.2.</strong> xxd</a></li><li class="chapter-item expanded "><a href="../binary/readelf.html"><strong aria-hidden="true">4.3.</strong> readelf</a></li><li class="chapter-item expanded "><a href="../binary/objdump.html"><strong aria-hidden="true">4.4.</strong> objdump</a></li><li class="chapter-item expanded "><a href="../binary/nm.html"><strong aria-hidden="true">4.5.</strong> nm</a></li></ol></li><li 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aria-hidden="true">5.7.</strong> symbol versioning</a></li><li class="chapter-item expanded "><a href="../development/python.html"><strong aria-hidden="true">5.8.</strong> python</a></li></ol></li><li class="chapter-item expanded "><a href="../linux/index.html"><strong aria-hidden="true">6.</strong> Linux</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../linux/systemd.html"><strong aria-hidden="true">6.1.</strong> systemd</a></li><li class="chapter-item expanded "><a href="../linux/coredump.html"><strong aria-hidden="true">6.2.</strong> coredump</a></li><li class="chapter-item expanded "><a href="../linux/ptrace_scope.html"><strong aria-hidden="true">6.3.</strong> ptrace_scope</a></li><li class="chapter-item expanded "><a href="../linux/cryptsetup.html"><strong aria-hidden="true">6.4.</strong> cryptsetup</a></li><li class="chapter-item expanded "><a href="../linux/swap.html"><strong aria-hidden="true">6.5.</strong> swap</a></li><li class="chapter-item expanded "><a href="../linux/input.html" class="active"><strong aria-hidden="true">6.6.</strong> input</a></li></ol></li><li class="chapter-item expanded "><a href="../network/index.html"><strong aria-hidden="true">7.</strong> Network</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../network/tcpdump.html"><strong aria-hidden="true">7.1.</strong> tcpdump</a></li><li class="chapter-item expanded "><a href="../network/firewall-cmd.html"><strong aria-hidden="true">7.2.</strong> firewall-cmd</a></li></ol></li><li class="chapter-item expanded "><a href="../web/index.html"><strong aria-hidden="true">8.</strong> Web</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../web/html.html"><strong aria-hidden="true">8.1.</strong> html</a></li><li class="chapter-item expanded "><a href="../web/chartjs.html"><strong aria-hidden="true">8.2.</strong> chartjs</a></li></ol></li><li class="chapter-item expanded "><a href="../arch/index.html"><strong 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(Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar"> + <i class="fa fa-search"></i> + </button> + </div> + + <h1 class="menu-title">Notes</h1> + + <div class="right-buttons"> + <a href="../print.html" title="Print this book" aria-label="Print this book"> + <i id="print-button" class="fa fa-print"></i> + </a> + <a href="https://github.com/johannst/notes" title="Git repository" aria-label="Git repository"> + <i id="git-repository-button" class="fa fa-github"></i> + </a> + </div> + </div> + + <div id="search-wrapper" class="hidden"> + <form id="searchbar-outer" class="searchbar-outer"> + <input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header"> + </form> + <div id="searchresults-outer" class="searchresults-outer hidden"> + <div id="searchresults-header" class="searchresults-header"></div> + <ul id="searchresults"> + </ul> + </div> + </div> + <!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM --> + <script type="text/javascript"> + document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible'); + document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible'); + Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) { + link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1); + }); + </script> + + <div id="content" class="content"> + <main> + <h1 id="linux-input"><a class="header" href="#linux-input">Linux input</a></h1> +<p>Some notes on using <code>/dev/input/*</code> device driver files.</p> +<h2 id="mousex--mice"><a class="header" href="#mousex--mice">mouseX / mice</a></h2> +<p>These device files are created by the [mousedev] driver.</p> +<ul> +<li><code>/dev/input/mouseX</code> represents the input stream for a <em>SINGLE</em> mouse device.</li> +<li><code>/dev/input/mice</code> represents the merged input stream for <em>ALL</em> mouse devices.</li> +</ul> +<p>The data stream consists of <code>3 bytes</code> per <code>event</code>. An event is encoded as <code>(BTN, X, Y)</code>.</p> +<ul> +<li><code>BTN</code> button pressed</li> +<li><code>X</code> movement in x-direction <code>-1 -> left</code> and <code>1 -> right</code></li> +<li><code>Y</code> movement in y-direction <code>-1 -> down</code> and <code>1 -> up</code></li> +</ul> +<p>The raw data stream can be inspected as follows.</p> +<pre><code class="language-bash">sudo cat /dev/input/mice | od -tx1 -w3 -v +</code></pre> +<h2 id="eventx"><a class="header" href="#eventx">eventX</a></h2> +<p>These device files are created by the [evdev] driver.</p> +<ul> +<li><code>/dev/input/eventX</code> represents the generic input event interface a <em>SINGLE</em> input deivece.</li> +</ul> +<p>Input events are encoded as given by the <code>input_event</code> struct below. Reading +from the <code>eventX</code> device file will always yield whole number of input events.</p> +<pre><code class="language-c">struct input_event { + struct timeval time; + unsigned short type; + unsigned short code; + unsigned int value; +}; +</code></pre> +<p>On most 64bit machines the raw data stream can be inspected as follows.</p> +<pre><code class="language-bash">sudo cat /dev/input/event4 | od -tx1 -w24 -v +</code></pre> +<h2 id="identifyin-device-files"><a class="header" href="#identifyin-device-files">Identifyin device files.</a></h2> +<p>To find out which device file is assigned to which input device the following +file <code>/proc/bus/input/devices</code> in the proc filesystem can be consulted.</p> +<p>This yields entries as follows and shows which <code>Handlers</code> are assigned to which +<code>Name</code>.</p> +<pre><code>I: Bus=0018 Vendor=04f3 Product=0033 Version=0000 +N: Name="Elan Touchpad" +... +H: Handlers=event15 mouse0 +... +</code></pre> +<h2 id="example-toying-with-devinputeventx"><a class="header" href="#example-toying-with-devinputeventx">Example: Toying with <code>/dev/input/eventX</code></a></h2> +<p>Once compiled, the example should be run as <code>sudo ./event /dev/input/eventX</code>.</p> +<pre><code class="language-c">#include <stdio.h> +#include <fcntl.h> +#include <assert.h> +#include <unistd.h> +#include <time.h> + +#include <sys/time.h> +#include <linux/input-event-codes.h> + +struct input_event { + struct timeval time; + unsigned short type; + unsigned short code; + unsigned int value; +}; + +const char* type(unsigned short t) { + static char buf[32]; + const char* fmt = "0x%x"; + switch (t) { +#define FMT(TYPE) case TYPE: fmt = #TYPE"(0x%x)"; break + FMT(EV_SYN); + FMT(EV_KEY); + FMT(EV_REL); + FMT(EV_ABS); +#undef FMT + } + snprintf(buf, sizeof(buf), fmt, t); + return buf; +} + +const char* code(unsigned short c) { + static char buf[32]; + const char* fmt = "0x%x"; + switch (c) { +#define FMT(CODE) case CODE: fmt = #CODE"(0x%x)"; break + FMT(BTN_LEFT); + FMT(BTN_RIGHT); + FMT(BTN_MIDDLE); + FMT(REL_X); + FMT(REL_Y); +#undef FMT + } + snprintf(buf, sizeof(buf), fmt, c); + return buf; +} + +const char* timefmt(const struct timeval* t) { + assert(t); + struct tm* lt = localtime(&t->tv_sec); // Returns pointer to static tm object. + static char buf[64]; + strftime(buf, sizeof(buf), "%H:%M:%S", lt); + return buf; +} + +int main(int argc, char* argv[]) { + assert(argc == 2); + + int fd = open(argv[1], O_RDONLY); + assert(fd != -1); + + struct input_event inp; + while (1) { + int ret = read(fd, &inp, sizeof(inp)); + assert(ret == sizeof(inp)); + printf("time: %s type: %s code: %s value: 0x%x\n", + timefmt(&inp.time), type(inp.type), code(inp.code), inp.value); + } +} +</code></pre> +<p>[mousedev]: TODO /home/johannst/dev/linux/drivers/input/mousedev.c +[evdev]: TODO /home/johannst/dev/linux/drivers/input/evdev.c</p> + + </main> + + <nav class="nav-wrapper" aria-label="Page navigation"> + <!-- Mobile navigation buttons --> + <a rel="prev" href="../linux/swap.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left"> + <i class="fa fa-angle-left"></i> + </a> + <a rel="next" href="../network/index.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right"> + <i class="fa fa-angle-right"></i> + </a> + <div style="clear: both"></div> + </nav> + </div> + </div> + + <nav class="nav-wide-wrapper" aria-label="Page navigation"> + <a rel="prev" href="../linux/swap.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left"> + <i class="fa fa-angle-left"></i> + </a> + <a rel="next" href="../network/index.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right"> + <i class="fa fa-angle-right"></i> + </a> + </nav> + + </div> + + <script type="text/javascript"> + window.playground_copyable = true; + </script> + <script src="../elasticlunr.min.js" type="text/javascript" charset="utf-8"></script> + <script src="../mark.min.js" type="text/javascript" charset="utf-8"></script> + <script src="../searcher.js" type="text/javascript" charset="utf-8"></script> + <script src="../clipboard.min.js" type="text/javascript" charset="utf-8"></script> + <script src="../highlight.js" type="text/javascript" charset="utf-8"></script> + <script src="../book.js" type="text/javascript" charset="utf-8"></script> + + <!-- Custom JS scripts --> + </body> +</html> |