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<HTML>
<HEAD>
<TITLE>crash utility maintenance guide</TITLE>
</HEAD>
<BODY>
<TABLE WIDTH=800PX>
<TR><TD style="font-size:34px">
<DIV ALIGN="CENTER"><B>Crash Utility Maintenance Guide</B></DIV>
</TR></TD>
</TABLE>
<P>
<TABLE>
<TR><TD>
Dave Anderson
</TD></TR>
</TABLE>
<P>Copyright © 2020 by Red Hat, Inc.<BR>
Copyright © 2021 by NEC Corporation</P>
<TABLE WIDTH=800PX>
<TR><TD>
Permission is granted to copy, distribute and/or modify this document under
the terms of the GNU Free Documentation License, Version 1.2 or any later
version published by the Free Software Foundation; with no Invariant Sections,
no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is
included in the section entitled "GNU Free Documentation License".
</TR></TD>
</TABLE>
<A NAME="contents"><BR><HR ALIGN=LEFT WIDTH=800PX><BR></A>
<TABLE WIDTH=800PX>
<TR>
<TD style="font-size:28px">
<B>Contents</B>
</TD>
<TD ALIGN=RIGHT>
<B><A HREF="crash_maintenance.html">[Prev]</A></B>
<B><A HREF="crash_maintenance.html#intro">[Next]</A></B>
</TD>
</TR>
</TABLE>
<FONT SIZE="+1">
<UL>
<LI><A HREF="crash_maintenance.html#intro">Introduction</A>
<LI><A HREF="crash_maintenance.html#source">Files</A>
<UL>
<LI><A HREF="crash_maintenance.html#github_sources">Github Repository</A>
<LI><A HREF="crash_maintenance.html#rhel_sources">RHEL Distribution</A>
<LI><A HREF="crash_maintenance.html#fedora_sources">Fedora Distribution</A>
<LI><A HREF="crash_maintenance.html#file_contents">Source Files</A>
<LI><A HREF="crash_maintenance.html#other_files">Other Files</A>
</UL>
<LI><A HREF="crash_maintenance.html#configuration">Configuration</A>
<LI><A HREF="crash_maintenance.html#build">Build Process</A>
<UL>
<LI><A HREF="crash_maintenance.html#toplevel">Top-Level Source Files</A>
<LI><A HREF="crash_maintenance.html#linkage">Linkage with GDB</A>
</UL>
<LI ><A HREF="crash_maintenance.html#global">Global Data</A>
<LI><A HREF="crash_maintenance.html#initialization">Initialization Sequence</A>
<UL>
<LI><A HREF="crash_maintenance.html#options">Command Line Options</A>
<LI><A HREF="crash_maintenance.html#setup_environment"><tt>setup_environment()</tt></A>
<LI><A HREF="crash_maintenance.html#main"><tt>main()</tt></A>
<LI><A HREF="crash_maintenance.html#GDB_init">GDB Initialization</A>
<LI><A HREF="crash_maintenance.html#main_loop"><tt>main_loop()</tt></A>
<LI><A HREF="crash_maintenance.html#init_backtrace">Post Initialization Backtrace</A>
</UL>
<LI><A HREF="crash_maintenance.html#runtime">Runtime Control Flow</A>
<UL>
<LI><A HREF="crash_maintenance.html#process_command_line"><tt>process_command_line()</tt></A>
<LI><A HREF="crash_maintenance.html#exec_command"><tt>exec_command()</tt></A>
</UL>
<LI><A HREF="crash_maintenance.html#commandexec">Command Execution</A>
<UL>
<LI><A HREF="crash_maintenance.html#arguments">Arguments</A>
<LI><A HREF="crash_maintenance.html#memalloc">Memory Allocation</A>
<LI><A HREF="crash_maintenance.html#utilityfunc">Utility Functions</A>
<LI><A HREF="crash_maintenance.html#errorhandling">Error Handling</A>
</UL>
<LI><A HREF="crash_maintenance.html#GDB_interface">GDB Interface</A>
<LI><A HREF="crash_maintenance.html#debugging">Debugging</A>
<UL>
<LI><A HREF="crash_maintenance.html#crashdebug"><tt>CRASHDEBUG()</tt></A>
<LI><A HREF="crash_maintenance.html#console"><tt>console()</tt></A>
<LI><A HREF="crash_maintenance.html#test_cmd"><tt>cmd_test()</tt></A>
</UL>
<LI><A HREF="crash_maintenance.html#extension">Extension Modules</A>
<UL>
<LI><A HREF="crash_maintenance.html#samples_ext">Package Samples</A>
<LI><A HREF="crash_maintenance.html#upstream_ext">Upstream</A>
<LI><A HREF="crash_maintenance.html#rhel_ext">RHEL Packages</A>
</UL>
<LI><A HREF="crash_maintenance.html#testing">Testing</A>
<LI><A HREF="crash_maintenance.html#pkgmaint">Package Maintenance</A>
<UL>
<LI><A HREF="crash_maintenance.html#github">Github</A>
<LI><A HREF="crash_maintenance.html#fedora">Fedora</A>
<LI><A HREF="crash_maintenance.html#rhel">RHEL</A>
<LI><A HREF="crash_maintenance.html#centos">CentOS Stream</A>
<LI><A HREF="crash_maintenance.html#people"><tt>people.redhat.com</tt></A>
<LI><A HREF="crash_maintenance.html#github_io"><tt>https://crash-utility.github.io</tt></A>
<LI><A HREF="crash_maintenance.html#cvs">CVS</A>
</UL>
<LI><A HREF="crash_maintenance.html#mailing">Crash Utility Mailing List</A>
<LI><A HREF="crash_maintenance.html#upstream">Monitoring Upstream Kernel Development</A>
<LI><A HREF="crash_maintenance.html#FAQ">Frequently Asked Questions</A>
<LI><A HREF="crash_maintenance.html#further">Further Information</A>
<LI><A HREF="crash_maintenance.html#GNU">GNU Free Documentation License</A>
</UL>
</FONT>
<TABLE WIDTH=800PX STYLE="PADDING-LEFT: 20PX">
<TR>
</TR>
<TR>
<TD>
<B><A HREF="crash_maintenance.html#contents">[Top]</A></B>
</TD>
<TD ALIGN=RIGHT>
<B><A HREF="crash_maintenance.html">[Prev]</A></B>
<B><A HREF="crash_maintenance.html#intro">[Next]</A></B>
</TD>
</TR>
</TABLE>
<BR><HR ALIGN=LEFT WIDTH=800PX><BR>
<P STYLE="PADDING:40EM;"></P>
<BR><A NAME="intro"><HR ALIGN=LEFT WIDTH=800PX></A><BR>
<TABLE WIDTH=800PX>
<TR>
<TD>
<FONT SIZE="+2"><B>Introduction</B></FONT>
</TD>
<TD ALIGN=RIGHT>
<B><A HREF="crash_maintenance.html#contents">[Prev]</A></B>
<B><A HREF="crash_maintenance.html#contents">[Contents]</A></B>
<B><A HREF="crash_maintenance.html#source">[Next]</A></B>
</TD>
</TR>
</TABLE>
<BR>
<TABLE WIDTH=800PX STYLE="PADDING-LEFT: 20PX">
<TR><TD>
This document contains several sections regarding the
design and maintenance of the crash utility.
It is intended to be a "live" document,
to be updated with additional information, better examples, and additional
<A HREF="crash_maintenance.html#FAQ">Frequently Asked Questions</A>.
</TR></TD>
</TABLE>
<TABLE WIDTH=800PX STYLE="PADDING-LEFT: 20PX">
<TR>
</TR>
<TR>
<TD>
<B><A HREF="crash_maintenance.html#intro">[Top]</A></B>
</TD>
<TD ALIGN=RIGHT>
<B><A HREF="crash_maintenance.html#contents">[Prev]</A></B>
<B><A HREF="crash_maintenance.html#contents">[Contents]</A></B>
<B><A HREF="crash_maintenance.html#source">[Next]</A></B>
</TD>
</TR>
</TABLE>
<BR><HR ALIGN=LEFT WIDTH=800PX><BR>
<P STYLE="PADDING:40EM;"></P>
<BR><A NAME="source"><HR ALIGN=LEFT WIDTH=800PX></A><BR>
<TABLE WIDTH=800PX>
<TR>
<TD>
<FONT SIZE="+2"><B>Files</B></FONT>
</TD>
<TD ALIGN=RIGHT>
<B><A HREF="crash_maintenance.html#intro">[Prev]</A></B>
<B><A HREF="crash_maintenance.html#contents">[Contents]</A></B>
<B><A HREF="crash_maintenance.html#configuration">[Next]</A></B>
</TD>
</TR>
</TABLE>
<BR>
<TABLE WIDTH=800PX>
<TR><TD>
<UL>
<FONT SIZE="+1">
<LI><A HREF="crash_maintenance.html#github_sources">Github Repository</A>
<LI><A HREF="crash_maintenance.html#rhel_sources">RHEL Distribution</A>
<LI><A HREF="crash_maintenance.html#fedora_sources">Fedora Distribution</A>
<LI><A HREF="crash_maintenance.html#file_contents">Source Files</A>
<LI><A HREF="crash_maintenance.html#other_files">Other Files</A>
</FONT>
</UL>
</TR></TD>
</TABLE>
<A NAME="github_sources"></A>
<TABLE WIDTH=800PX STYLE="PADDING-LEFT: 20PX">
<TR>
<TD>
<FONT SIZE="+1"><BR><B><U>Github Repository</U></B></FONT>
</TD>
<TD ALIGN=RIGHT>
<B><A HREF="crash_maintenance.html#source">[Top]</A></B>
</TD>
</TR>
<TR><TD><BR>
The crash utility sources consist of the following:
</TD></TR>
</TABLE>
<BLOCKQUOTE>
<pre>
$ <B>git clone git:https://github.com/crash-utility/crash.git</B>
Cloning into 'crash'...
remote: Enumerating objects: 12, done.
remote: Counting objects: 100% (12/12), done.
remote: Compressing objects: 100% (9/9), done.
remote: Total 2897 (delta 5), reused 10 (delta 3), pack-reused 2885
Receiving objects: 100% (2897/2897), 5.43 MiB | 1.41 MiB/s, done.
Resolving deltas: 100% (1952/1952), done.
$ <B>cd crash</B>
$ <B>ls</B>
alpha.c lkcd_fix_mem.h sadump.c
arm64.c lkcd_v1.c sadump.h
arm.c lkcd_v2_v3.c sparc64.c
bpf.c lkcd_v5.c symbols.c
cmdline.c lkcd_v7.c task.c
configure.c lkcd_v8.c test.c
COPYING3 lkcd_vmdump_v1.h tools.c
crash.8 lkcd_vmdump_v2_v3.h unwind_arm.c
defs.h lkcd_x86_trace.c unwind.c
dev.c lkcd_x86_trace.h unwind_decoder.c
diskdump.c main.c unwind.h
diskdump.h makedumpfile.c unwind_i.h
extensions/ makedumpfile.h unwind_x86_32_64.c
extensions.c Makefile unwind_x86_64.h
filesys.c memory.c unwind_x86.h
gdb-7.6.patch memory_driver/ vas_crash.h
gdb-7.6-ppc64le-support.patch mips.c va_server.c
gdb-7.6-proc_service.h.patch net.c va_server.h
gdb_interface.c netdump.c va_server_v1.c
global_data.c netdump.h vmcore.h
help.c ppc64.c vmware_vmss.c
ia64.c ppc.c vmware_vmss.h
ibm_common.h qemu.c x86_64.c
ipcs.c qemu-load.c x86.c
kaslr_helper.c qemu-load.h xen_dom0.c
kernel.c ramdump.c xen_dom0.h
kvmdump.c README xendump.c
kvmdump.h remote.c xendump.h
lkcd_common.c rse.h xen_hyper.c
lkcd_dump_v5.h s390.c xen_hyper_command.c
lkcd_dump_v7.h s390dbf.c xen_hyper_defs.h
lkcd_dump_v8.h s390_dump.c xen_hyper_dump_tables.c
lkcd_fix_mem.c s390x.c xen_hyper_global_data.c
$
</pre>
</BLOCKQUOTE>
<TABLE WIDTH=800PX STYLE="PADDING-LEFT: 20PX"><TR><TD>
Note that the GDB sources are not included in the
<A HREF="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/crash-utility/crash">github</A>
repository.
There are 3 GDB patch files:
<P>
<TABLE WIDTH=800PX STYLE="PADDING-LEFT: 20PX"><TR><TD>
<BL>
<LI><tt>gdb-7.6.patch</tt> file is always applied.
<LI><tt>gdb-7.6-ppc64le-support.patch</tt> is only applied for the ppc64le architecture.
<LI><tt>gdb-7.6-proc_service.h.patch</tt> is applied depending upon the contents of <i>/usr/include/proc_service.h</i>
</BL>
</TR></TD>
</TABLE>
<P>
The <tt>extensions</tt> subdirectory contains a small set of <i><b>sample</b></i>
extension modules. New extension modules should not be added to this directory:
</TD></TR></TABLE>
<BLOCKQUOTE>
<pre>
$ <b>ls extensions</b>
dminfo.c echo.c eppic.c eppic.mk Makefile snap.c snap.mk trace.c
$
</BLOCKQUOTE>
<TABLE WIDTH=800PX STYLE="PADDING-LEFT: 20PX">
<TR><TD>
The <tt>memory_driver</tt> subdirectory contains a sample kernel driver
that is similar to the old <i>/dev/crash</i> driver. Given that /proc/kcore has
been stabilized for use on live systems, the sample driver is pretty much obsolete:
</TD></TR></TABLE>
<BLOCKQUOTE>
<pre>
$ <b>ls memory_driver</b>
crash.c Makefile README
$
</pre>
</BLOCKQUOTE>
<TABLE WIDTH=800PX STYLE="PADDING-LEFT: 20PX">
<TR><TD>
Lastly, unshown above is the hidden <tt>.rh_rpm_package</tt> file, which contains
the package version number.
</TD></TR></TABLE>
<BR>
<A NAME="rhel_sources"></A>
<TABLE WIDTH=800PX STYLE="PADDING-LEFT: 20PX">
<TR><TD>
<FONT SIZE="+1"><BR><B><U>RHEL Distribution</U></B></FONT>
</TD>
<TD ALIGN=RIGHT>
<B><A HREF="crash_maintenance.html#source">[Top]</A></B>
</TD>
</TR>
<TR><TD><BR>
The RHEL sources, at a minimum, consist of the following:
<pre>
$ <b>rpm -qpl crash-7.2.6-1.el8.src.rpm</b>
crash-7.2.6.tar.gz
crash.spec
lzo_snappy.patch
rhel8_build.patch
$
</pre>
The <tt>crash-7.2.6.tar.gz</tt> file contains all of the
<A HREF="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/crash-utility/crash">github</A>
sources <b>plus</b>
the GDB source files. The GDB sources were downloaded from the FSF web site,
where currently <tt>gdb-7.6.tar.gz</tt> is being used:
<pre>
$ <b>tar tvzmf crash-7.2.6.tar.gz | grep tar.gz</b>
-rw-r--r-- root/root 31437633 2019-09-20 10:36 crash-7.2.7/gdb-7.6.tar.gz
$
</pre>
The <tt>lzo_snappy.patch</tt>
file causes the LZO and snappy compression libraries to be built into the crash binary.
RHEL8 requires the <tt>rhel8_build.patch</tt>, which causes the crash sources to be compiled with -fPIE,
the crash binary to linked with "-Wl,-z,now -fpie", and the host build system's
LDFLAGS contents to be utilized.
<P>
If/when the release numbers get bumped from -1 and beyond, additional patches may be added to the lists above.
See the <A HREF="crash_maintenance.html#rhel">RHEL Package Maintenance</A> section for details.
</TR></TD>
</TABLE>
<BR>
<A NAME="fedora_sources"></A>
<TABLE WIDTH=800PX STYLE="PADDING-LEFT: 20PX">
<TR><TD>
<FONT SIZE="+1"><BR><B><U>Fedora Distribution</U></B></FONT>
</TD>
<TD ALIGN=RIGHT>
<B><A HREF="crash_maintenance.html#source">[Top]</A></B>
</TD>
</TR>
<TR><TD><BR>
The Fedora sources, at a minimum, consist of the following:
<pre>
$ <b>rpm -qpl crash-7.2.6-1.fc31.src.rpm</b>
crash-7.2.6.tar.gz
crash.spec
lzo_snappy.patch
use_system_readline_v3.patch
$
</pre>
The <tt>crash-7.2.6.tar.gz</tt> file contains all of the
<A HREF="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/crash-utility/crash">github</A>
sources <b>plus</b>
the GDB source files. The GDB sources were downloaded from the FSF
web site, where currently <tt>gdb-7.6.tar.gz</tt> is being used:
<pre>
$ <b>tar tvzmf crash-7.2.6.tar.gz | grep tar.gz</b>
-rw-r--r-- root/root 31437633 2019-09-20 10:36 crash-7.2.6/gdb-7.6.tar.gz
$
</pre>
The <tt>lzo_snappy.patch</tt>
file causes the LZO and snappy compression libraries to be built into the crash binary.
Fedora requires the <tt>use_system_readline_v3.patch</tt>, which causes the build to utilize the host
system's <tt>readline</tt> library instead of the <tt>readline</tt> library that is bundled in the GDB sources.
<P>
If/when the release numbers get bumped from -1 and beyond, additional patches may be added to the lists above.
See the <A HREF="crash_maintenance.html#fedora">Fedora Package Maintenance</A> section for details.
</TR></TD>
</TABLE>
<BR>
<A NAME="file_contents"></A>
<TABLE WIDTH=800PX STYLE="PADDING-LEFT: 20PX">
<TR><TD>
<FONT SIZE="+1"><BR><B><U>Source Files</U></B></FONT>
</TD>
<TD ALIGN=RIGHT>
<B><A HREF="crash_maintenance.html#source">[Top]</A></B>
</TD>
</TR>
<TR><TD><BR>
The build is configured by the interaction of these two files. See the
<A HREF="crash_maintenance.html#configuration">Configuration</A> and
<A HREF="crash_maintenance.html#build">Build Process</A> sections for details:
<BR><BR>
<BL>
<LI><tt>configure.c</tt>
<LI><tt>Makefile</tt>
</BL>
<BR><BR>
The RHEL crash utility RPM packages are bundled with the current version
of GDB, which was downloaded from the Free Software Foundation
<A HREF="http:https://ftp.gnu.org/gnu/gdb"><tt>http:https://ftp.gnu.org/gnu/gdb</tt></A>
website. When building from
a git tree, it is downloaded dynamically:
<BR><BR>
<BL>
<LI><tt>gdb-7.6.tar.gz</tt>
</BL>
<BR><BR>
There is one major header file that most of the C files include,
which is the only file contained in the <tt>crash-devel</tt> RPM package:
<BR><BR>
<BL>
<LI><tt>defs.h</tt>
</BL>
<BR><BR>
Each of the supported architectures contains its own file, containing
numerous machine-specific functions that must exist for each architecture.
The majority of the text within each file is conditionally compiled
because it is contained within per-architecture <tt>#ifdef/#endif</tt> directives:
<BR><BR>
<BL>
<LI><tt>alpha.c</tt>
<LI><tt>arm64.c</tt>
<LI><tt>arm.c</tt>
<LI><tt>ia64.c</tt>
<LI><tt>mips.c</tt>
<LI><tt>ppc64.c</tt>
<LI><tt>ppc.c</tt>
<LI><tt>s390.c</tt>
<LI><tt>s390x.c</tt>
<LI><tt>sparc64.c</tt>
<LI><tt>x86_64.c</tt>
<LI><tt>x86.c</tt>
</BL>
<BL>
<BR>
<BR>
Support for the various memory sources are contained in several files.
Historically, the first supported dumpfile type was the Mcore kernel patch
from Mission Critical Linux:
<BR><BR>
<BL>
<LI><tt>vas_crash.h</tt>
<LI><tt>va_server.c</tt>
<LI><tt>va_server.h</tt>
<LI><tt>va_server_v1.c</tt>
</BL>
<BR><BR>
That was followed by support for the LKCD kernel patch from Silicon Graphics.
Both Mcore and LKCD were never accepted into the upstream kernel tree,
and for all practical purposes are obsolete. However, the LKCD format
apparently still exists in some IBM configurations:
<BR><BR>
<BL>
<LI><tt>lkcd_common.c</tt>
<LI><tt>lkcd_dump_v5.h</tt>
<LI><tt>lkcd_dump_v7.h</tt>
<LI><tt>lkcd_dump_v8.h</tt>
<LI><tt>lkcd_fix_mem.c</tt>
<LI><tt>lkcd_fix_mem.h</tt>
<LI><tt>lkcd_v1.c</tt>
<LI><tt>lkcd_v2_v3.c</tt>
<LI><tt>lkcd_v5.c</tt>
<LI><tt>lkcd_v7.c</tt>
<LI><tt>lkcd_v8.c</tt>
<LI><tt>lkcd_vmdump_v1.h</tt>
<LI><tt>lkcd_vmdump_v2_v3.h</tt>
</BL>
<BR><BR>
Support for ELF format dumpfiles was first introduced by the Red Hat Netdump facility,
and then subsequently by the Kdump facility, and the Xen ELF format. The support for
all ELF format dumpfiles is contained in these two files:
<BR><BR>
<BL>
<LI><tt>netdump.c</tt>
<LI><tt>netdump.h</tt>
</BL>
<BR><BR>
The original compressed dumpfile format was the Diskdump facility introduced by
Fujitsu. That format was later utilized and expanded upon by the
compressed Kdump format:
<BR><BR>
<BL>
<LI><tt>diskdump.c</tt>
<LI><tt>diskdump.h</tt>
</BL>
<BR><BR>
Another compressed dumpfile is the Fujitsu SADUMP, created
by the Fujitsu Stand Alone Dump facility. The dump-creation
mechanism is initiated from hardware-specific firmware, generating a dumpfile in three
different formats: sadump dump device (single partition), sadump dump
device (disk set), and archive file formats:
<BR><BR>
<BL>
<LI><tt>sadump.c</tt>
<LI><tt>sadump.h</tt>
</BL>
<BR><BR>
The original Xen dumpfile format was the XC_SAVE format produced by the <tt>xm save</tt> command,
and later the XC_CORE_ORIG format created by the <tt>xc_domain_dumpcore()</tt> library function in
<tt>libxc/xc_core.c</tt>, and lastly an XC_CORE_ELF format, which has also has support in
<tt>netdump.c</tt>:
<BR><BR>
<BL>
<LI><tt>xendump.c</tt>
<LI><tt>xendump.h</tt>
<LI><tt>xen_dom0.c</tt>
<LI><tt>xen_dom0.h</tt>
</BL>
<BR><BR>
When a dom0 kernel or its underlying Xen hypervisor binary crashes, a single vmcore file is created.
To analyze the vmcore from the perspective of the Xen hypervisor, support was added to
allow the substitution of the <tt>vmlinux</tt> file with a <tt>xen-syms</tt> file.
A separate set of commands exists for such an invocation:
<BR><BR>
<BL>
<LI><tt>xen_hyper.c</tt>
<LI><tt>xen_hyper_command.c</tt>
<LI><tt>xen_hyper_defs.h</tt>
<LI><tt>xen_hyper_dump_tables.c</tt>
<LI><tt>xen_hyper_global_data.c</tt>
</BL>
<BR><BR>
The original dumpfile format produced by the KVM <tt>virsh dump</tt> command
was based upon its "save-vm" format. It was not well-suited for use as a
dumpfile because it was not designed to be random access:
<BR><BR>
<BL>
<LI><tt>qemu.c</tt>
<LI><tt>qemu-load.c</tt>
<LI><tt>qemu-load.h</tt>
<LI><tt>kvmdump.c</tt>
<LI><tt>kvmdump.h</tt>
</BL>
<BR><BR>
The original s390/s390x native dumpfile format was essentially a
copy of physical memory created by the IBM stand-alone dump tool:
<BR><BR>
<BL>
<LI><tt>ibm_common.h</tt>
<LI><tt>s390_dump.c</tt>
</BL>
<BR><BR>
Support was added for <tt>makedumpfile</tt>'s "vmcore.flat" dumpfile format,
so that it is not necessary to revert the flattened-format dumpfile back into
an ELF vmcore or compressed kdump vmcore with <tt>makedumpfile -R</tt>", or with
the <tt>makedumpfile-R.pl</tt> script. It is a slower invocation, because
the crash utility needs to perform the physical memory "rearrangement" during
its initialization sequence:
<BR><BR>
<BL>
<LI><tt>makedumpfile.h</tt>
<LI><tt>makedumpfile.c</tt>
</BL>
<BR><BR>
Support for VMware VMSS suspended state dumpfiles is here:
<BR><BR>
<BL>
<LI><tt>vmware_vmss.c</tt>
<LI><tt>vmware_vmss.h</tt>
</BL>
<BR><BR>
Support was added for raw RAM dump files, which get transformed into temporary
ELF format files for analysis. This file is also used for remote "live"
ramdump files as referenced below in the <tt>remote.c</tt>
description:
<BR><BR>
<BL>
<LI><tt>ramdump.c</tt>
</BL>
<BR><BR>
Originally there was support for running the crash utility against
dumpfiles that were located on a remote host, which required that the
deprecated "crash daemon" was running on the remote host. That functionality
has been obsolete for many years; however the remote functionality has been
somewhat resurrected for two rare cases. One is for use with a "xen-crashd" daemon running
on a Xen Dom0 host, which communicates with a paused or shutdown DomU
guest kernel. The second is for support of "live" ramdump files, such as
those that are specified by the QEMU mem-path argument of a memory-backend-file
object, which allows the running of a live crash session against a
QEMU guest from the host machine:
<BR><BR>
<BL>
<LI><tt>remote.c</tt>
</BL>
<BR><BR>
In addition to containing the crash utility's <tt>main()</tt> invocation
function, this file accomplishes such things as the program context initialization,
initiates the interaction with the embedded GDB module, contains the
command execution loop, and contains
the <tt>mach</tt> and <tt>quit</tt> commands:
<BR><BR>
<BL>
<LI><tt>main.c</tt>
</BL>
<BR><BR>
There are several global data structures that can be referenced directly by any
other file are collected in one file. These include the <tt>program_context</tt>,
the <tt>task_table</tt>, the <tt>kernel_table</tt>, the <tt>vm_table</tt>,
the <tt>machdep_table</tt>,
the <tt>symbol_table_data</tt> tables; these tables can be referenced by the
<tt>pc</tt>,
<tt>tt</tt>,
<tt>kt</tt>,
<tt>vm</tt>,
<tt>machdep</tt>,
and <tt>st</tt> global pointers respectively. This file also contains
the <tt>args[]</tt>, <tt>argscnt</tt> and
<tt>argerrs</tt> for command-gathering, the <tt>linux_command_table[]</tt>,
the <tt>extension_table</tt> for linking extension module commands, and the <tt>offset_table</tt>, <tt>size_table</tt> and
<tt>array_table</tt> for storing commonly-used structure offsets, structure sizes, and array sizes:
<BR><BR>
<BL>
<LI><tt>global_data.c</tt>
</BL>
<BR><BR>
Support for gathering symbol table information from the <tt>vmlinux</tt>
file for use during runtime, the <tt>sym</tt>,
<tt>sym</tt>,
<tt>struct</tt>,
<tt>union</tt>,
<tt>*</tt>
and <tt>p</tt> commands,
as well as numerous symbol-related utility
functions are found here:
<BR><BR>
<BL>
<LI><tt>symbols.c</tt>
</BL>
<BR><BR>
Command line handling and support functions, and the
<tt>alias</tt> and
<tt>repeat</tt> commands are contained here:
<BR><BR>
<BL>
<LI><tt>cmdline.c</tt>
</BL>
<BR><BR>
Communication functions with the embedded GDB module, and the
generic <tt>gdb</tt> command are contained here:
<BR><BR>
<BL>
<LI><tt>gdb_interface.c</tt>
</BL>
<BR><BR>
Physical and virtual memory-specific initialization, support functions, and the
<tt>rd</tt>,
<tt>wr</tt>,
<tt>ptov</tt>,
<tt>vtop</tt>,
<tt>vm</tt>,
<tt>ptob</tt>,
<tt>btop</tt>,
<tt>kmem</tt>,
<tt>search</tt>,
<tt>swap</tt> and
<tt>pte</tt> commands are here:
<BR><BR>
<BL>
<LI><tt>memory.c</tt>
</BL>
<BR><BR>
Kernel-specific initialization, support functions, and the
<tt>bt</tt>,
<tt>dis</tt>,
<tt>mod</tt>,
<tt>log</tt>,
<tt>sys</tt>,
<tt>irq</tt>,
<tt>timer</tt> and
<tt>waitq</tt> commands are here:
<BR><BR>
<BL>
<LI><tt>kernel.c</tt>
</BL>
<BR><BR>
Task-specific initialization, support functions, and the
<tt>ps</tt>,
<tt>task</tt>,
<tt>foreach</tt>,
<tt>runq</tt> and
<tt>sig</tt> commands are here:
<BR><BR>
<BL>
<LI><tt>task.c</tt>
</BL>
<BR><BR>
File system-specific initialization, support functions, and the
<tt>mount</tt>,
<tt>files</tt> and
<tt>fuser</tt> commands are here:
<BR><BR>
<BL>
<LI><tt>filesys.c</tt>
</BL>
<BR><BR>
Device-specific initialization, support functions, and the <tt>dev</tt>
command are contained here:
<BR><BR>
<BL>
<LI><tt>dev.c</tt>
</BL>
<BR><BR>
Support for the dumping of the NT_VMCOREDD vmcore ELF note requires this header:
<BR><BR>
<BL>
<LI><tt>vmcore.h</tt>
</BL>
<BR><BR>
Network-specific initialization, support functions, and the <tt>net</tt> command
are contained here:
<BR><BR>
<BL>
<LI><tt>net.c</tt>
</BL>
<BR><BR>
Numerous commonly-used utility functions, and the
<tt>set</tt>,
<tt>eval</tt>,
<tt>list</tt> and
<tt>tree</tt> commands are here:
<BR><BR>
<BL>
<LI><tt>tools.c</tt>
</BL>
<BR><BR>
The <tt>ipcs</tt> command and its support functions are contained here:
<BR><BR>
<BL>
<LI><tt>ipcs.c</tt>
</BL>
<BR><BR>
The <tt>bpf</tt> command and its support functions are contained here:
<BR><BR>
<BL>
<LI><tt>bpf.c</tt>
</BL>
<BR><BR>
The hidden <tt>test</tt> debug/test command is contained here:
<BR><BR>
<BL>
<LI><tt>ipcs.c</tt>
</BL>
<BR><BR>
The <tt>help</tt> command and its support functions are contained here:
<BR><BR>
<BL>
<LI><tt>help.c</tt>
</BL>
<BR><BR>
The extension module <tt>extend</tt> command and its support functions are contained here:
<BR><BR>
<BL>
<LI><tt>extensions.c</tt>
</BL>
<BR><BR>
The <tt>s390dbf</tt> command and its support functions are contained here:
<BR><BR>
<BL>
<LI><tt>s390dbf.c</tt>
</BL>
<BR><BR>
The 32-bit x86 <tt>bt</tt> command uses a modified version of the old LKCD backtrace
code:
<BR><BR>
<BL>
<LI><tt>lkcd_x86_trace.c</tt>
<LI><tt>lkcd_x86_trace.h</tt>
</BL>
<BR><BR>
Functions required for KASLR offset calculation when the relevant
vmcoreinfo data is not contained in the dumpfile are found here:
<BR><BR>
<BL>
<LI><tt>kaslr_helper.c</tt>
</BL>
<BR><BR>
Backtrace support in older kernel versions could optionally use the kernel's
Dwarf unwind tables:
<BR><BR>
<BL>
<LI><tt>unwind_arm.c</tt>
<LI><tt>rse.h</tt>
<LI><tt>unwind.c</tt>
<LI><tt>unwind_decoder.c</tt>
<LI><tt>unwind.h</tt>
<LI><tt>unwind_i.h</tt>
<LI><tt>unwind_x86_32_64.c</tt>
<LI><tt>unwind_x86_64.h</tt>
<LI><tt>unwind_x86.h</tt>
</BL>
<BR><BR>
There are 3 patches for the current version of GDB that
are required to marry it with the crash utility code:
<BR><BR>
<BL>
<LI><tt>gdb-7.6.patch</tt>
<LI><tt>gdb-7.6-ppc64le-support.patch</tt>
<LI><tt>gdb-7.6-proc_service.h.patch</tt>
</BL>
<BR><BR>
The <tt>CRASH(8)</tt> man page is here:
<BR><BR>
<BL>
<LI><tt>crash.8</tt>
</BL>
<BR><BR>
The crash utility's README file is generated/updated by the <tt>crash -h README</tt> command,
which is called by the <tt>make files</tt>, <tt>make tar</tt> and <tt>make release</tt>
targets to update its contents slightly, for example, to show the current crash utility
version number:
<BR><BR>
<BL>
<LI><tt>README</tt>
</BL>
<BR><BR>
The crash utility's version number is generated by the <tt>make RPMPKG=</tt><<i>version</i>>
target, or it can be modified manually:
<BR><BR>
<BL>
<LI><tt>.rh_rpm_package</tt>
</BL>
<BR><BR>
The GPLv3 license that must be included with the package is here:
<BR><BR>
<BL>
<LI><tt>COPYING3</tt>
</BL>
<BR><BR>
The <tt>extensions/</tt> subdirectory contains a set of
sample extension modules and requisite makefiles. See the
<A HREF="crash_maintenance.html#extension">Extension Modules</A>
section for details:
<BR><BR>
<BL>
<LI><tt>dminfo.c</tt>
<LI><tt>echo.c</tt>
<LI><tt>eppic.c</tt>
<LI><tt>eppic.mk</tt>
<LI><tt>Makefile</tt>
<LI><tt>snap.c</tt>
<LI><tt>snap.mk</tt>
<LI><tt>trace.c</tt>
</BL>
<BR><BR>
The <tt>memory_driver/</tt> subdirectory contains a
a sample <tt>/dev/crash</tt> memory driver for live
system analysis if <tt>/dev/mem</tt> and/or <tt>/proc/kcore</tt>
are unavailable on a host machine:
<BR><BR>
<BL>
<LI><tt>crash.c</tt>
<LI><tt>Makefile</tt>
<LI><tt>README</tt>
</BL>
</TR></TD>
</TABLE>
<A NAME="other_files"></A>
<TABLE WIDTH=800PX STYLE="PADDING-LEFT: 20PX">
<TR><TD>
<FONT SIZE="+1"><BR><B><U>Other Files</U></B></FONT>
</TD>
<TD ALIGN=RIGHT>
<B><A HREF="crash_maintenance.html#source">[Top]</A></B>
</TD>
<BR><BR>
</TR>
<TR><TD>
<BR>
There are several files that are not part of the original source
tree. Most importantly, is the current version
of GDB, which gets downloaded from the Free Software Foundation
<A HREF="http:https://ftp.gnu.org/gnu/gdb"><tt>http:https://ftp.gnu.org/gnu/gdb</tt></A>
website during the initial build; the file is bundled with RHEL and Fedora
<tt>crash-</tt><<i>version</i>></tt>.src.rpm</tt> file:
<BR><BR>
<BL>
<LI><tt>gdb-7.6.tar.gz</tt>
</BL>
<BR><BR>
The following files are not part of the original source tree. They
are created dynamically or manually.
<p>
The resultant build data is created by this file and stored in the
crash utility binary, which can be viewed during runtime by <tt>help -B</tt>.
This file is created dynamically each time a build is done:
<BL>
<LI><tt>build_data.c</tt>
</BL>
<BR><BR>
With older versions of GDB, certain files were excluded from
being extracted from the <tt>gdb-</tt><<i>version</i>><tt>.tar.gz</tt>
file. This file is created automatically during the initial build, and it
contained a list of files to be excluded.
With the current version of <tt>gdb-7.6</tt>, it is obsolete:
<BR><BR>
<BL>
<LI><tt>gdb.files</tt>
</BL>
<BR><BR>
These two files allow a user to apply extra CFLAGS and LDFLAGS
options to the compilation:
<BR><BR>
<BL>
<LI><tt>CFLAGS.extra</tt>
<LI><tt>LDFLAGS.extra</tt>
</BL>