diff options
Diffstat (limited to 'share/doc/gdb/Core-File-Generation.html')
| -rw-r--r-- | share/doc/gdb/Core-File-Generation.html | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/share/doc/gdb/Core-File-Generation.html b/share/doc/gdb/Core-File-Generation.html new file mode 100644 index 0000000..66c82e9 --- /dev/null +++ b/share/doc/gdb/Core-File-Generation.html @@ -0,0 +1,156 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1988-2023 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with the +Invariant Sections being "Free Software" and "Free Software Needs +Free Documentation", with the Front-Cover Texts being "A GNU Manual," +and with the Back-Cover Texts as in (a) below. + +(a) The FSF's Back-Cover Text is: "You are free to copy and modify +this GNU Manual. Buying copies from GNU Press supports the FSF in +developing GNU and promoting software freedom." --> +<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>Debugging with GDB: Core File Generation</title> + +<meta name="description" content="Debugging with GDB: Core File Generation"> +<meta name="keywords" content="Debugging with GDB: Core File Generation"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<link href="index.html#Top" rel="start" title="Top"> +<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Data.html#Data" rel="up" title="Data"> +<link href="Character-Sets.html#Character-Sets" rel="next" title="Character Sets"> +<link href="Dump_002fRestore-Files.html#Dump_002fRestore-Files" rel="previous" title="Dump/Restore Files"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.indentedblock {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smallindentedblock {margin-left: 3.2em; font-size: smaller} +div.smalllisp {margin-left: 3.2em} +kbd {font-style:oblique} +pre.display {font-family: inherit} +pre.format {font-family: inherit} +pre.menu-comment {font-family: serif} +pre.menu-preformatted {font-family: serif} +pre.smalldisplay {font-family: inherit; font-size: smaller} +pre.smallexample {font-size: smaller} +pre.smallformat {font-family: inherit; font-size: smaller} +pre.smalllisp {font-size: smaller} +span.nocodebreak {white-space:nowrap} +span.nolinebreak {white-space:nowrap} +span.roman {font-family:serif; font-weight:normal} +span.sansserif {font-family:sans-serif; font-weight:normal} +ul.no-bullet {list-style: none} +--> +</style> + + +</head> + +<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="Core-File-Generation"></a> +<div class="header"> +<p> +Next: <a href="Character-Sets.html#Character-Sets" accesskey="n" rel="next">Character Sets</a>, Previous: <a href="Dump_002fRestore-Files.html#Dump_002fRestore-Files" accesskey="p" rel="previous">Dump/Restore Files</a>, Up: <a href="Data.html#Data" accesskey="u" rel="up">Data</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="How-to-Produce-a-Core-File-from-Your-Program"></a> +<h3 class="section">10.20 How to Produce a Core File from Your Program</h3> +<a name="index-dump-core-from-inferior"></a> + +<p>A <em>core file</em> or <em>core dump</em> is a file that records the memory +image of a running process and its process status (register values +etc.). Its primary use is post-mortem debugging of a program that +crashed while it ran outside a debugger. A program that crashes +automatically produces a core file, unless this feature is disabled by +the user. See <a href="Files.html#Files">Files</a>, for information on invoking <small>GDB</small> in +the post-mortem debugging mode. +</p> +<p>Occasionally, you may wish to produce a core file of the program you +are debugging in order to preserve a snapshot of its state. +<small>GDB</small> has a special command for that. +</p> +<dl compact="compact"> +<dd><a name="index-gcore"></a> +<a name="index-generate_002dcore_002dfile"></a> +</dd> +<dt><code>generate-core-file [<var>file</var>]</code></dt> +<dt><code>gcore [<var>file</var>]</code></dt> +<dd><p>Produce a core dump of the inferior process. The optional argument +<var>file</var> specifies the file name where to put the core dump. If not +specified, the file name defaults to <samp>core.<var>pid</var></samp>, where +<var>pid</var> is the inferior process ID. +</p> +<p>Note that this command is implemented only for some systems (as of +this writing, <small>GNU</small>/Linux, FreeBSD, Solaris, and S390). +</p> +<p>On <small>GNU</small>/Linux, this command can take into account the value of the +file <samp>/proc/<var>pid</var>/coredump_filter</samp> when generating the core +dump (see <a href="#set-use_002dcoredump_002dfilter">set use-coredump-filter</a>), and by default honors the +<code>VM_DONTDUMP</code> flag for mappings where it is present in the file +<samp>/proc/<var>pid</var>/smaps</samp> (see <a href="#set-dump_002dexcluded_002dmappings">set dump-excluded-mappings</a>). +</p> +<a name="index-set-use_002dcoredump_002dfilter"></a> +<a name="set-use_002dcoredump_002dfilter"></a></dd> +<dt><code>set use-coredump-filter on</code></dt> +<dt><code>set use-coredump-filter off</code></dt> +<dd><p>Enable or disable the use of the file +<samp>/proc/<var>pid</var>/coredump_filter</samp> when generating core dump +files. This file is used by the Linux kernel to decide what types of +memory mappings will be dumped or ignored when generating a core dump +file. <var>pid</var> is the process ID of a currently running process. +</p> +<p>To make use of this feature, you have to write in the +<samp>/proc/<var>pid</var>/coredump_filter</samp> file a value, in hexadecimal, +which is a bit mask representing the memory mapping types. If a bit +is set in the bit mask, then the memory mappings of the corresponding +types will be dumped; otherwise, they will be ignored. This +configuration is inherited by child processes. For more information +about the bits that can be set in the +<samp>/proc/<var>pid</var>/coredump_filter</samp> file, please refer to the +manpage of <code>core(5)</code>. +</p> +<p>By default, this option is <code>on</code>. If this option is turned +<code>off</code>, <small>GDB</small> does not read the <samp>coredump_filter</samp> file +and instead uses the same default value as the Linux kernel in order +to decide which pages will be dumped in the core dump file. This +value is currently <code>0x33</code>, which means that bits <code>0</code> +(anonymous private mappings), <code>1</code> (anonymous shared mappings), +<code>4</code> (ELF headers) and <code>5</code> (private huge pages) are active. +This will cause these memory mappings to be dumped automatically. +</p> +<a name="index-set-dump_002dexcluded_002dmappings"></a> +<a name="set-dump_002dexcluded_002dmappings"></a></dd> +<dt><code>set dump-excluded-mappings on</code></dt> +<dt><code>set dump-excluded-mappings off</code></dt> +<dd><p>If <code>on</code> is specified, <small>GDB</small> will dump memory mappings +marked with the <code>VM_DONTDUMP</code> flag. This flag is represented in +the file <samp>/proc/<var>pid</var>/smaps</samp> with the acronym <code>dd</code>. +</p> +<p>The default value is <code>off</code>. +</p></dd> +</dl> + +<hr> +<div class="header"> +<p> +Next: <a href="Character-Sets.html#Character-Sets" accesskey="n" rel="next">Character Sets</a>, Previous: <a href="Dump_002fRestore-Files.html#Dump_002fRestore-Files" accesskey="p" rel="previous">Dump/Restore Files</a>, Up: <a href="Data.html#Data" accesskey="u" rel="up">Data</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |