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| <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
| "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
| <!-- SPDX-License-Identifier: LGPL-2.1-or-later --> |
| |
| <refentry id="systemd-dissect" conditional='HAVE_BLKID' |
| xmlns:xi="http://www.w3.org/2001/XInclude"> |
| |
| <refentryinfo> |
| <title>systemd-dissect</title> |
| <productname>systemd</productname> |
| </refentryinfo> |
| |
| <refmeta> |
| <refentrytitle>systemd-dissect</refentrytitle> |
| <manvolnum>1</manvolnum> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>systemd-dissect</refname> |
| <refpurpose>Dissect file system OS images</refpurpose> |
| </refnamediv> |
| |
| <refsynopsisdiv> |
| <cmdsynopsis> |
| <command>systemd-dissect <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="plain"><replaceable>IMAGE</replaceable></arg></command> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>systemd-dissect <arg choice="opt" rep="repeat">OPTIONS</arg> <option>--mount</option> <arg choice="plain"><replaceable>IMAGE</replaceable></arg> <arg choice="plain"><replaceable>PATH</replaceable></arg></command> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>systemd-dissect <arg choice="opt" rep="repeat">OPTIONS</arg> <option>--copy-from</option> <arg choice="plain"><replaceable>IMAGE</replaceable></arg> <arg choice="plain"><replaceable>PATH</replaceable></arg> <arg choice="opt"><replaceable>TARGET</replaceable></arg></command> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>systemd-dissect <arg choice="opt" rep="repeat">OPTIONS</arg> <option>--copy-to</option> <arg choice="plain"><replaceable>IMAGE</replaceable></arg> <arg choice="opt"><replaceable>SOURCE</replaceable></arg> <arg choice="plain"><replaceable>PATH</replaceable></arg></command> |
| </cmdsynopsis> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para><command>systemd-dissect</command> is a tool for introspecting and interacting with file system OS |
| disk images. It supports four different operations:</para> |
| |
| <orderedlist> |
| <listitem><para>Show general OS image information, including the image's |
| <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry> data, |
| machine ID, partition information and more.</para></listitem> |
| |
| <listitem><para>Mount an OS image to a local directory. In this mode it will dissect the OS image and |
| mount the included partitions according to their designation onto a directory and possibly |
| sub-directories.</para></listitem> |
| |
| <listitem><para>Copy files and directories in and out of an OS image.</para></listitem> |
| </orderedlist> |
| |
| <para>The tool may operate on three types of OS images:</para> |
| |
| <orderedlist> |
| <listitem><para>OS disk images containing a GPT partition table envelope, with partitions marked |
| according to the <ulink url="https://systemd.io/DISCOVERABLE_PARTITIONS">Discoverable Partitions |
| Specification</ulink>.</para></listitem> |
| |
| <listitem><para>OS disk images containing just a plain file-system without an enveloping partition |
| table. (This file system is assumed to be the root file system of the OS.)</para></listitem> |
| |
| <listitem><para>OS disk images containing a GPT or MBR partition table, with a single |
| partition only. (This partition is assumed to contain the root file system of the OS.)</para></listitem> |
| </orderedlist> |
| |
| <para>OS images may use any kind of Linux-supported file systems. In addition they may make use of LUKS |
| disk encryption, and contain Verity integrity information. Note that qualifying OS images may be booted |
| with <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s |
| <option>--image=</option> switch, and be used as root file system for system service using the |
| <varname>RootImage=</varname> unit file setting, see |
| <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> |
| |
| <para>Note that the partition table shown when invoked without command switch (as listed below) does not |
| necessarily show all partitions included in the image, but just the partitions that are understood and |
| considered part of an OS disk image. Specifically, partitions of unknown types are ignored, as well as |
| duplicate partitions (i.e. more than one per partition type), as are root and <filename>/usr/</filename> |
| partitions of architectures not compatible with the local system. In other words: this tool will display |
| what it operates with when mounting the image. To display the complete list of partitions use a tool such |
| as <citerefentry |
| project='man-pages'><refentrytitle>fdisk</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Commands</title> |
| |
| <para>If neither of the command switches listed below are passed the specified disk image is opened and |
| general information about the image and the contained partitions and their use is shown.</para> |
| |
| <variablelist> |
| <varlistentry> |
| <term><option>--mount</option></term> |
| <term><option>-m</option></term> |
| |
| <listitem><para>Mount the specified OS image to the specified directory. This will dissect the image, |
| determine the OS root file system — as well as possibly other partitions — and mount them to the |
| specified directory. If the OS image contains multiple partitions marked with the <ulink |
| url="https://systemd.io/DISCOVERABLE_PARTITIONS">Discoverable Partitions Specification</ulink> |
| multiple nested mounts are established. This command expects two arguments: a path to an image file |
| and a path to a directory where to mount the image.</para> |
| |
| <para>To unmount an OS image mounted like this use <citerefentry |
| project='man-pages'><refentrytitle>umount</refentrytitle><manvolnum>8</manvolnum></citerefentry>'s |
| <option>-R</option> switch (for recursive operation), so that the OS image and all nested partition |
| mounts are unmounted.</para> |
| |
| <para>When the OS image contains LUKS encrypted or Verity integrity protected file systems |
| appropriate volumes are automatically set up and marked for automatic disassembly when the image is |
| unmounted.</para> |
| |
| <para>The OS image may either be specified as path to an OS image stored in a regular file or may |
| refer to block device node (in the latter case the block device must be the "whole" device, i.e. not |
| a partition device). (The other supported commands described here support this, too.)</para> |
| |
| <para>All mounted file systems are checked with the appropriate <citerefentry |
| project='man-pages'><refentrytitle>fsck</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| implementation in automatic fixing mode, unless explicitly turned off (<option>--fsck=no</option>) or |
| read-only operation is requested (<option>--read-only</option>).</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>-M</option></term> |
| |
| <listitem><para>This is a shortcut for <option>--mount --mkdir</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--copy-from</option></term> |
| <term><option>-x</option></term> |
| |
| <listitem><para>Copies a file or directory from the specified OS image into the specified location on |
| the host file system. Expects three arguments: a path to an image file, a source path (relative to |
| the image's root directory) and a destination path (relative to the current working directory, or an |
| absolute path, both outside of the image). If the destination path is omitted or specified as dash |
| (<literal>-</literal>), the specified file is written to standard output. If the source path in the |
| image file system refers to a regular file it is copied to the destination path. In this case access |
| mode, extended attributes and timestamps are copied as well, but file ownership is not. If the source |
| path in the image refers to a directory, it is copied to the destination path, recursively with all |
| containing files and directories. In this case the file ownership is copied too.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--copy-to</option></term> |
| <term><option>-a</option></term> |
| |
| <listitem><para>Copies a file or directory from the specified location in the host file system into |
| the specified OS image. Expects three arguments: a path to an image file, a source path (relative to |
| the current working directory, or an absolute path, both outside of the image) and a destination path |
| (relative to the image's root directory). If the source path is omitted or specified as dash |
| (<literal>-</literal>), the data to write is read from standard input. If the source path in the host |
| file system refers to a regular file, it is copied to the destination path. In this case access mode, |
| extended attributes and timestamps are copied as well, but file ownership is not. If the source path |
| in the host file system refers to a directory it is copied to the destination path, recursively with |
| all containing files and directories. In this case the file ownership is copied |
| too.</para> |
| |
| <para>As with <option>--mount</option> file system checks are implicitly run before the copy |
| operation begins.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--json=</option><replaceable>MODE</replaceable></term> |
| |
| <listitem><para>Shows output formatted as JSON. Expects one of <literal>short</literal> (for the |
| shortest possible output without any redundant whitespace or line breaks), <literal>pretty</literal> |
| (for a pretty version of the same, with indentation and line breaks) or <literal>off</literal> (to turn |
| off json output).</para></listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| <xi:include href="standard-options.xml" xpointer="version" /> |
| </variablelist> |
| |
| </refsect1> |
| |
| <refsect1> |
| <title>Options</title> |
| |
| <para>The following options are understood:</para> |
| |
| <variablelist> |
| <varlistentry> |
| <term><option>--read-only</option></term> |
| <term><option>-r</option></term> |
| |
| <listitem><para>Operate in read-only mode. By default <option>--mount</option> will establish |
| writable mount points. If this option is specified they are established in read-only mode |
| instead.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--fsck=no</option></term> |
| |
| <listitem><para>Turn off automatic file system checking. By default when an image is accessed for |
| writing (by <option>--mount</option> or <option>--add</option>) the file systems contained in the OS |
| image are automatically checked using the appropriate <citerefentry |
| project='man-pages'><refentrytitle>fsck</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| command, in automatic fixing mode. This behavior may be switched off using |
| <option>--fsck=no</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--mkdir</option></term> |
| |
| <listitem><para>If combined with <option>--mount</option> the directory to mount the OS image to is |
| created if it is missing. Note that the directory is not automatically removed when the disk image is |
| unmounted again.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--discard=</option></term> |
| |
| <listitem><para>Takes one of <literal>disabled</literal>, <literal>loop</literal>, |
| <literal>all</literal>, <literal>crypto</literal>. If <literal>disabled</literal> the image is |
| accessed with empty block discarding turned off. if <literal>loop</literal> discarding is enabled if |
| operating on a regular file. If <literal>crypt</literal> discarding is enabled even on encrypted file |
| systems. If <literal>all</literal> discarding is unconditionally enabled.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--root-hash=</option></term> |
| <term><option>--root-hash-sig=</option></term> |
| <term><option>--verity-data=</option></term> |
| |
| <listitem><para>Configure various aspects of Verity data integrity for the OS |
| image. <option>--root-hash=</option> expects a hex-encoding top-level Verity hash to use for setting |
| up the Verity integrity protection. <option>--root-hash-sig=</option> expects the path to a file |
| containing a PKCS#7 signature file for the hash. This signature is passed to the kernel during |
| activation, which will match it against signature keys available in the kernel |
| keyring. <option>--verity-data=</option> expects the path to a file with the Verity data to use for |
| the OS image, in case it is stored in a detached file. It is recommended to embed the Verity data |
| directly in the image, using the Verity mechanisms in the <ulink |
| url="https://systemd.io/DISCOVERABLE_PARTITIONS">Discoverable Partitions Specification</ulink>.</para></listitem> |
| </varlistentry> |
| |
| </variablelist> |
| |
| </refsect1> |
| |
| <refsect1> |
| <title>Exit status</title> |
| |
| <para>On success, 0 is returned, a non-zero failure code |
| otherwise.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>See Also</title> |
| <para> |
| <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| <ulink url="https://systemd.io/DISCOVERABLE_PARTITIONS">Discoverable Partitions Specification</ulink>, |
| <citerefentry project='man-pages'><refentrytitle>umount</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
| <citerefentry project='man-pages'><refentrytitle>fdisk</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| </para> |
| </refsect1> |
| |
| </refentry> |