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diff --git a/tools/gdb.html b/tools/gdb.html deleted file mode 100644 index d4f7f24..0000000 --- a/tools/gdb.html +++ /dev/null @@ -1,676 +0,0 @@ -<!DOCTYPE HTML> -<html lang="en" class="light" dir="ltr"> - <head> - <!-- Book generated using mdBook --> - <meta charset="UTF-8"> - <title>gdb - Notes</title> - - - <!-- Custom HTML head --> - - <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 class="sidebar-visible no-js"> - <div id="body-container"> - <!-- Provide site root to javascript --> - <script> - var path_to_root = "../"; - var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? 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</script> - - <input type="checkbox" id="sidebar-toggle-anchor" class="hidden"> - - <!-- Hide / unhide sidebar before it is displayed --> - <script> - var body = document.querySelector('body'); - var sidebar = null; - var sidebar_toggle = document.getElementById("sidebar-toggle-anchor"); - if (document.body.clientWidth >= 1080) { - try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { } - sidebar = sidebar || 'visible'; - } else { - sidebar = 'hidden'; - } - sidebar_toggle.checked = sidebar === 'visible'; - body.classList.remove('sidebar-visible'); - body.classList.add("sidebar-" + sidebar); - </script> - - <nav id="sidebar" class="sidebar" aria-label="Table of contents"> - <div class="sidebar-scrollbox"> - <ol class="chapter"><li class="chapter-item expanded affix "><a href="../intro.html">Introduction</a></li><li class="chapter-item expanded "><a href="../tools/index.html"><strong aria-hidden="true">1.</strong> Tools</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../tools/zsh.html"><strong aria-hidden="true">1.1.</strong> zsh</a></li><li class="chapter-item expanded "><a href="../tools/bash.html"><strong 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" class="active"><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 class="chapter-item expanded "><a href="../tools/radare2.html"><strong aria-hidden="true">1.11.</strong> radare2</a></li><li class="chapter-item expanded "><a href="../tools/qemu.html"><strong aria-hidden="true">1.12.</strong> qemu</a></li><li class="chapter-item expanded "><a href="../tools/pacman.html"><strong aria-hidden="true">1.13.</strong> pacman</a></li><li class="chapter-item expanded "><a href="../tools/dot.html"><strong aria-hidden="true">1.14.</strong> dot</a></li><li class="chapter-item expanded "><a href="../tools/ffmpeg.html"><strong aria-hidden="true">1.15.</strong> ffmpeg</a></li><li class="chapter-item expanded "><a href="../tools/column.html"><strong aria-hidden="true">1.16.</strong> column</a></li><li class="chapter-item expanded "><a href="../tools/sort.html"><strong aria-hidden="true">1.17.</strong> sort</a></li><li class="chapter-item expanded "><a href="../tools/sed.html"><strong aria-hidden="true">1.18.</strong> sed</a></li><li class="chapter-item expanded "><a href="../tools/gnuplot.html"><strong aria-hidden="true">1.19.</strong> gnuplot</a></li></ol></li><li class="chapter-item expanded "><a href="../monitor/index.html"><strong aria-hidden="true">2.</strong> Resource analysis & monitor</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../monitor/lsof.html"><strong aria-hidden="true">2.1.</strong> lsof</a></li><li class="chapter-item expanded "><a href="../monitor/ss.html"><strong aria-hidden="true">2.2.</strong> ss</a></li><li class="chapter-item expanded "><a href="../monitor/pidstat.html"><strong aria-hidden="true">2.3.</strong> pidstat</a></li><li class="chapter-item expanded "><a href="../monitor/pgrep.html"><strong aria-hidden="true">2.4.</strong> pgrep</a></li><li class="chapter-item expanded "><a href="../monitor/ps.html"><strong aria-hidden="true">2.5.</strong> ps</a></li><li class="chapter-item expanded "><a href="../monitor/pmap.html"><strong aria-hidden="true">2.6.</strong> pmap</a></li><li class="chapter-item expanded "><a href="../monitor/pstack.html"><strong aria-hidden="true">2.7.</strong> pstack</a></li></ol></li><li class="chapter-item expanded "><a href="../trace_profile/index.html"><strong aria-hidden="true">3.</strong> Trace and Profile</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../trace_profile/time.html"><strong aria-hidden="true">3.1.</strong> time</a></li><li class="chapter-item expanded "><a href="../trace_profile/strace.html"><strong aria-hidden="true">3.2.</strong> strace</a></li><li class="chapter-item expanded "><a href="../trace_profile/ltrace.html"><strong aria-hidden="true">3.3.</strong> ltrace</a></li><li class="chapter-item expanded "><a href="../trace_profile/perf.html"><strong aria-hidden="true">3.4.</strong> perf</a></li><li class="chapter-item expanded "><a href="../trace_profile/oprofile.html"><strong aria-hidden="true">3.5.</strong> OProfile</a></li><li class="chapter-item expanded "><a href="../trace_profile/callgrind.html"><strong aria-hidden="true">3.6.</strong> callgrind</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 class="chapter-item expanded "><a href="../development/index.html"><strong aria-hidden="true">5.</strong> Development</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../development/c++filt.html"><strong aria-hidden="true">5.1.</strong> c++filt</a></li><li class="chapter-item expanded "><a href="../development/c++.html"><strong aria-hidden="true">5.2.</strong> c++</a></li><li class="chapter-item expanded "><a href="../development/glibc.html"><strong aria-hidden="true">5.3.</strong> glibc</a></li><li class="chapter-item expanded "><a href="../development/gcc.html"><strong aria-hidden="true">5.4.</strong> gcc</a></li><li class="chapter-item expanded "><a href="../development/cmake.html"><strong aria-hidden="true">5.5.</strong> cmake</a></li><li class="chapter-item expanded "><a href="../development/make.html"><strong aria-hidden="true">5.6.</strong> make</a></li><li class="chapter-item expanded "><a href="../development/ld.so.html"><strong aria-hidden="true">5.7.</strong> ld.so</a></li><li class="chapter-item expanded "><a href="../development/symbolver.html"><strong aria-hidden="true">5.8.</strong> symbol versioning</a></li><li class="chapter-item expanded "><a href="../development/python.html"><strong aria-hidden="true">5.9.</strong> python</a></li><li class="chapter-item expanded "><a href="../development/gcov.html"><strong aria-hidden="true">5.10.</strong> gcov</a></li><li class="chapter-item expanded "><a href="../development/pgo.html"><strong aria-hidden="true">5.11.</strong> pgo</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"><strong aria-hidden="true">6.6.</strong> input</a></li><li class="chapter-item expanded "><a href="../linux/acl.html"><strong aria-hidden="true">6.7.</strong> acl</a></li><li class="chapter-item expanded "><a href="../linux/zfs.html"><strong aria-hidden="true">6.8.</strong> zfs</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/tshark.html"><strong aria-hidden="true">7.2.</strong> tshark</a></li><li class="chapter-item expanded "><a href="../network/firewall-cmd.html"><strong aria-hidden="true">7.3.</strong> firewall-cmd</a></li><li class="chapter-item expanded "><a href="../network/nftables.html"><strong aria-hidden="true">7.4.</strong> nftables</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/css.html"><strong aria-hidden="true">8.2.</strong> css</a></li><li class="chapter-item expanded "><a href="../web/chartjs.html"><strong aria-hidden="true">8.3.</strong> chartjs</a></li></ol></li><li class="chapter-item expanded "><a href="../arch/index.html"><strong aria-hidden="true">9.</strong> Arch</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../arch/x86_64.html"><strong aria-hidden="true">9.1.</strong> x86_64</a></li><li class="chapter-item expanded "><a href="../arch/arm64.html"><strong aria-hidden="true">9.2.</strong> arm64</a></li><li class="chapter-item expanded "><a href="../arch/armv7.html"><strong aria-hidden="true">9.3.</strong> armv7</a></li><li class="chapter-item expanded "><a href="../arch/riscv.html"><strong aria-hidden="true">9.4.</strong> riscv</a></li></ol></li></ol> - </div> - <div id="sidebar-resize-handle" class="sidebar-resize-handle"> - <div class="sidebar-resize-indicator"></div> - </div> - </nav> - - <!-- Track and set sidebar scroll position --> - <script> - var sidebarScrollbox = document.querySelector('#sidebar .sidebar-scrollbox'); - sidebarScrollbox.addEventListener('click', function(e) { - if (e.target.tagName === 'A') { - 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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> - 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="gdb1"><a class="header" href="#gdb1">gdb(1)</a></h1> -<h1 id="cli"><a class="header" href="#cli">CLI</a></h1> -<pre><code class="language-markdown"> gdb [opts] [prg [-c coredump | -p pid]] - gdb [opts] --args prg <prg-args> - opts: - -p <pid> attach to pid - -c <coredump> use <coredump> - -x <file> execute script <file> before prompt - -ex <cmd> execute command <cmd> before prompt - --tty <tty> set I/O tty for debugee - --batch run in batch mode, exit after processing options (eg used - for scripting) - --batch-silent link --batch, but surpress gdb stdout -</code></pre> -<h1 id="interactive-usage"><a class="header" href="#interactive-usage">Interactive usage</a></h1> -<h2 id="misc"><a class="header" href="#misc">Misc</a></h2> -<pre><code class="language-markdown"> apropos <regex> - Search commands matching regex. - - tty <tty> - Set <tty> as tty for debugee. - Make sure nobody reads from target tty, easiest is to spawn a shell - and run following in target tty: - > while true; do sleep 1024; done - - sharedlibrary [<regex>] - Load symbols of shared libs loaded by debugee. Optionally use <regex> - to filter libs for symbol loading. - - display [/FMT] <expr> - Print <expr> every time debugee stops. Eg print next instr, see - examples below. - - undisplay [<num>] - Delete display expressions either all or one referenced by <num>. - - info display - List display expressions. - - info sharedlibrary [<regex>] - List shared libraries loaded. Optionally use <regex> to filter. -</code></pre> -<h2 id="breakpoints"><a class="header" href="#breakpoints">Breakpoints</a></h2> -<pre><code class="language-markdown"> break [-qualified] <sym> thread <tnum> - Set a breakpoint only for a specific thread. - -qualified: Treat <sym> as fully qualified symbol (quiet handy to set - breakpoints on C symbols in C++ contexts) - - break <sym> if <cond> - Set conditional breakpoint (see examples below). - - delete [<num>] - Delete breakpoint either all or one referenced by <num>. - - info break - List breakpoints. - - cond <bp> <cond> - Make existing breakpoint <bp> conditional with <cond>. - - cond <bp> - Remove condition from breakpoint <bp>. - - tbreak - Set temporary breakpoint, will be deleted when hit. - Same syntax as `break`. - - rbreak <regex> - Set breakpoints matching <regex>, where matching internally is done - on: .*<regex>.* - - command [<bp_list>] - Define commands to run after breakpoint hit. If <bp_list> is not - specified attach command to last created breakpoint. Command block - terminated with 'end' token. - - <bp_list>: Space separates list, eg 'command 2 5-8' to run command - for breakpoints: 2,5,6,7,8. - - save break <file> - Save breakpoints to <file>. Can be loaded with the `source` command. -</code></pre> -<h2 id="watchpoints"><a class="header" href="#watchpoints">Watchpoints</a></h2> -<pre><code class="language-markdown"> watch [-location|-l] <expr> [thread <tnum>] - Create a watchpoint for <expr>, will break if <expr> is written to. - Watchpoints respect scope of variables, -l can be used to watch the - memory location instead. - - rwatch ... - Sets a read watchpoint, will break if <expr> is read from. - - awatch ... - Sets an access watchpoint, will break if <expr> is written to or read - from. -</code></pre> -<h2 id="catchpoints"><a class="header" href="#catchpoints">Catchpoints</a></h2> -<pre><code class="language-markdown"> catch load [<regex>] - Stop when shared libraries are loaded, optionally specify a <regex> - to stop only on matches. - catch unload [<regex>] - Stop when shared libraries are unloaded, optionally specify a <regex> - to stop only on matches. - - catch throw - Stop when an exception is thrown. - catch rethrow - Stop when an exception is rethrown. - catch catch - Stop when an exception is caught. - - catch fork - Stop at calls to fork (also stops at clones, as some systems - implement fork via clone). - - catch syscall [<syscall> <syscall> ..] - Stop at syscall. If no argument is given, stop at all syscalls. - Optionally give a list of syscalls to stop at. -</code></pre> -<h2 id="inspection"><a class="header" href="#inspection">Inspection</a></h2> -<pre><code class="language-markdown"> info functions [<regex>] - List functions matching <regex>. List all functions if no <regex> - provided. - - info variables [<regex>] - List variables matching <regex>. List all variables if no <regex> - provided. - - info register [<reg> <reg> ..] - Dump content of all registers or only the specified <reg>ister. -</code></pre> -<h2 id="signal-handling"><a class="header" href="#signal-handling">Signal handling</a></h2> -<pre><code class="language-markdown"> info handle [<signal>] - Print how to handle <signal>. If no <signal> specified print for all - signals. - - handle <signal> <action> - Configure how gdb handles <signal> sent to debugee. - <action>: - stop/nostop Catch signal in gdb and break. - print/noprint Print message when gdb catches signal. - pass/nopass Pass signal down to debugee. - - catch signal <signal> - Create a catchpoint for <signal>. -</code></pre> -<h2 id="multi-threading"><a class="header" href="#multi-threading">Multi-threading</a></h2> -<pre><code class="language-markdown">info thread - List all threads. - -thread apply <id> [<id>] <command> - Run command on all threads listed by <id> (space separated list). - When 'all' is specified as <id> the <command> is run on all threads. - -thread name <name> - The <name> for the current thread. -</code></pre> -<h2 id="multi-process"><a class="header" href="#multi-process">Multi-process</a></h2> -<pre><code class="language-markdown"> set follow-fork-mode <child | parent> - Specify which process to follow when debuggee makes a fork(2) - syscall. - - set detach-on-fork <on | off> - Turn on/off detaching from new child processes (on by default). - Turning this off allows to debug multiple processes (inferiors) with - one gdb session. - - info inferiors - List all processes gdb debugs. - - inferior <id> - Switch to inferior with <id>. -</code></pre> -<h2 id="scheduling"><a class="header" href="#scheduling">Scheduling</a></h2> -<pre><code class="language-markdown"> set schedule-multiple <on | off> - on: Resume all threads of all processes (inferiors) when continuing - or stepping. - off: (default) Resume only threads of current process (inferior). -</code></pre> -<h2 id="shell-commands"><a class="header" href="#shell-commands">Shell commands</a></h2> -<pre><code class="language-markdown"> shell <shell_cmd> - Run the shell_cmd and print the output, can also contain a pipeline. - - pipe <gdb_cmd> | <shell_cmd> - Evaluate the gdb_cmd and run the shell_cmd which receives the output - of the gdb_cmd via stdin. -</code></pre> -<h2 id="source-file-locations"><a class="header" href="#source-file-locations">Source file locations</a></h2> -<pre><code class="language-markdown"> dir <path> - Add <path> to the beginning of the searh path for source files. - - show dir - Show current search path. - - set substitute-path <from> <to> - Add substitution rule checked during source file lookup. - - show substitute-path - Show current substitution rules. -</code></pre> -<h2 id="configuration"><a class="header" href="#configuration">Configuration</a></h2> -<pre><code class="language-markdown"> set disassembly-flavor <intel | att> - Set the disassembly style "flavor". - - set pagination <on | off> - Turn on/off gdb's pagination. - - set breakpoint pending <on | off | auto> - on: always set pending breakpoints. - off: error when trying to set pending breakpoints. - auto: interatively query user to set breakpoint. - - set print pretty <on | off> - Turn on/off pertty printing of structures. - - set style enabled <on | off> - Turn on/off styling (eg colored output). - - set logging <on | off> - Enable output logging to file (default gdb.txt). - - set logging file <fname> - Change output log file to <fname> - - set logging redirect <on | off> - on: only log to file. - off: log to file and tty. - - set logging overwrite <on | off> - on: Truncate log file on each run. - off: Append to logfile (default). - - set history filename <fname> - Change file where to save and restore command history to and from. - - set history <on | off> - Enable or disable saving of command history. -</code></pre> -<blockquote> -<p>Logging options should be configured before logging is turned on.</p> -</blockquote> -<h1 id="text-user-interface-tui"><a class="header" href="#text-user-interface-tui">Text user interface (TUI)</a></h1> -<pre><code class="language-markdown"> C-x a Toggle UI. - C-l Redraw UI (curses UI can be messed up after the debugee prints to - stdout/stderr). - C-x o Change focus. -</code></pre> -<h1 id="user-commands-macros"><a class="header" href="#user-commands-macros">User commands (macros)</a></h1> -<p>Gdb allows to create & document user commands as follows:</p> -<pre><code class="language-markdown"> define <cmd> - # cmds - end - - document <cmd> - # docu - end -</code></pre> -<p>To get all user commands or documentations one can use:</p> -<pre><code class="language-markdown"> help user-defined - help <cmd> -</code></pre> -<h1 id="hooks"><a class="header" href="#hooks">Hooks</a></h1> -<p>Gdb allows to create two types of command <code>hooks</code></p> -<ul> -<li><code>hook-</code> will be run before <code><cmd></code></li> -<li><code>hookpost-</code> will be run after <code><cmd></code></li> -</ul> -<pre><code class="language-markdown"> define hook-<cmd> - # cmds - end - - define hookpost-<cmd> - # cmds - end -</code></pre> -<h1 id="examples"><a class="header" href="#examples">Examples</a></h1> -<h2 id="automatically-print-next-instr"><a class="header" href="#automatically-print-next-instr">Automatically print next instr</a></h2> -<p>When ever the debugee stops automatically print the memory at the current -instruction pointer (<code>$rip</code> x86) and format as instruction <code>/i</code>.</p> -<pre><code class="language-markdown"> # rip - x86 - display /i $rip - - # step instruction, after the step the next instruction is automatically printed - si -</code></pre> -<h2 id="conditional-breakpoints"><a class="header" href="#conditional-breakpoints">Conditional breakpoints</a></h2> -<p>Create conditional breakpoints for a function <code>void foo(int i)</code> in the debugee.</p> -<pre><code class="language-markdown"> # Create conditional breakpoint - b foo if i == 42 - - b foo # would create bp 2 - # Make existing breakpoint conditional - cond 2 i == 7 -</code></pre> -<h2 id="set-breakpoint-on-all-threads-except-one"><a class="header" href="#set-breakpoint-on-all-threads-except-one">Set breakpoint on all threads except one</a></h2> -<p>Create conditional breakpoint using the <code>$_thread</code> <a href="https://sourceware.org/gdb/onlinedocs/gdb/Convenience-Vars.html#Convenience-Vars">convenience -variable</a>.</p> -<pre><code class="language-markdown"> # Create conditional breakpoint on all threads except thread 12. - b foo if $_thread != 12 -</code></pre> -<h2 id="catch-sigsegv-and-execute-commands"><a class="header" href="#catch-sigsegv-and-execute-commands">Catch SIGSEGV and execute commands</a></h2> -<p>This creates a <code>catchpoint</code> for the <code>SIGSEGV</code> signal and attached the <code>command</code> -to it.</p> -<pre><code class="language-markdown"> catch signal SIGSEGV - command - bt - c - end -</code></pre> -<h2 id="run-backtrace-on-thread-1-batch-mode"><a class="header" href="#run-backtrace-on-thread-1-batch-mode">Run <code>backtrace</code> on thread 1 (batch mode)</a></h2> -<pre><code class="language-markdown"> gdb --batch -ex 'thread 1' -ex 'bt' -p <pid> -</code></pre> -<h2 id="script-gdb-for-automating-debugging-sessions"><a class="header" href="#script-gdb-for-automating-debugging-sessions">Script gdb for automating debugging sessions</a></h2> -<p>To script gdb add commands into a file and pass it to gdb via <code>-x</code>. -For example create <code>run.gdb</code>:</p> -<pre><code class="language-markdown"> set pagination off - - break mmap - command - info reg rdi rsi rdx - bt - c - end - - #initial drop - c -</code></pre> -<p>This script can be used as:</p> -<pre><code class="language-markdown"> gdb --batch -x ./run.gdb -p <pid> -</code></pre> -<h2 id="hook-to-automatically-save-breakpoints-on-quit"><a class="header" href="#hook-to-automatically-save-breakpoints-on-quit">Hook to automatically save breakpoints on <code>quit</code></a></h2> -<pre><code class="language-markdown">define break-save - save breakpoint $arg0.gdb.bp -end -define break-load - source $arg0.gdb.bp -end - -define hook-quit - break-save quit -end -</code></pre> -<h2 id="watchpoint-on-struct--class-member"><a class="header" href="#watchpoint-on-struct--class-member">Watchpoint on struct / class member</a></h2> -<p>A symbolic watchpoint defined on a member variable for debugging is only valid -as long as the expression is in scope. Once out of scope the watchpoint gets -deleted.</p> -<p>When debugging some memory corruption we want to keep the watchpoint even the -expression goes out of scope to find the location that overrides the variable -and introduces the corruption.</p> -<pre><code class="language-markdown">(gdb) l -1 struct S { int v; }; -2 -3 void set(struct S* s, int v) { -4 s->v = v; -5 } -6 -7 int main() { -8 struct S s; -9 set(&s, 1); -10 set(&s, 2); -11 set(&s, 3); -... - -(gdb) s -set (s=0x7fffffffe594, v=1) at test.c:4 -4 s->v = v; - -# Define a new watchpoint on the member of the struct. The expression however -# is only valid in the current functions scope. - -(gdb) watch s->v -Hardware watchpoint 2: s->v - -(gdb) c -Hardware watchpoint 2: s->v -Old value = 0 -New value = 1 -set (s=0x7fffffffe594, v=1) at test.c:5 -5 } - -# The watchpoint gets deleted as soon as we leave the function scope. - -(gdb) c -Watchpoint 2 deleted because the program has left the block in -which its expression is valid. -main () at test.c:10 -10 set(&s, 2); - -# Define the watchpoint on the location of the object to watch. - -(gdb) watch -l s->v - -# This is equivalent to the following. - -(gdb) p &s->v -$1 = (int *) 0x7fffffffe594 - -# Define a watchpoint to the address of the member variable of the s instance. -# This of course only makes sense as long as the s instance is not moved in memory. - -(gdb) watch *0x7fffffffe594 -Hardware watchpoint 3: *0x7fffffffe594 - -(gdb) c -Hardware watchpoint 3: *0x7fffffffe594 -Old value = 1 -New value = 2 -set (s=0x7fffffffe594, v=2) at test.c:5 -5 } - -(gdb) c -Hardware watchpoint 3: *0x7fffffffe594 -Old value = 2 -New value = 3 -set (s=0x7fffffffe594, v=3) at test.c:5 -5 } -</code></pre> -<h2 id="shell-commands-1"><a class="header" href="#shell-commands-1">Shell commands</a></h2> -<pre><code class="language-markdown"># Run shell commands. - -(gdb) shell zcat /proc/config.gz | grep CONFIG_KVM= -CONFIG_KVM=m - -# Pipe gdb command to shell command. - -(gdb) pipe info proc mapping | grep libc - 0x7ffff7a1a000 0x7ffff7a42000 0x28000 0x0 r--p /usr/lib/libc.so.6 - 0x7ffff7a42000 0x7ffff7b9d000 0x15b000 0x28000 r-xp /usr/lib/libc.so.6 - 0x7ffff7b9d000 0x7ffff7bf2000 0x55000 0x183000 r--p /usr/lib/libc.so.6 - 0x7ffff7bf2000 0x7ffff7bf6000 0x4000 0x1d7000 r--p /usr/lib/libc.so.6 - 0x7ffff7bf6000 0x7ffff7bf8000 0x2000 0x1db000 rw-p /usr/lib/libc.so.6 -</code></pre> -<h1 id="know-bugs"><a class="header" href="#know-bugs">Know Bugs</a></h1> -<h2 id="workaround-command--finish-bug"><a class="header" href="#workaround-command--finish-bug">Workaround <code>command + finish</code> bug</a></h2> -<p>When using <code>finish</code> inside a <code>command</code> block, commands after <code>finish</code> are not -executed. To workaround that bug one can create a wrapper function which calls -<code>finish</code>.</p> -<pre><code class="language-markdown"> define handler - bt - finish - info reg rax - end - - command - handler - end -</code></pre> - - </main> - - <nav class="nav-wrapper" aria-label="Page navigation"> - <!-- Mobile navigation buttons --> - <a rel="prev" href="../tools/gpg.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 prefetch" href="../tools/gdbserver.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="../tools/gpg.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 prefetch" href="../tools/gdbserver.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> - window.playground_copyable = true; - </script> - - - <script src="../elasticlunr.min.js"></script> - <script src="../mark.min.js"></script> - <script src="../searcher.js"></script> - - <script src="../clipboard.min.js"></script> - <script src="../highlight.js"></script> - <script src="../book.js"></script> - - <!-- Custom JS scripts --> - - - </div> - </body> -</html> |