systemd/man/sd_device_get_syspath.xml

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
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<refentry id="sd_device_get_syspath"
          xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>sd_device_get_syspath</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>sd_device_get_syspath</refentrytitle>
    <manvolnum>3</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>sd_device_get_syspath</refname>
    <refname>sd_device_get_devpath</refname>
    <refname>sd_device_get_sysname</refname>
    <refname>sd_device_get_sysnum</refname>
    <refname>sd_device_get_subsystem</refname>
    <refname>sd_device_get_devtype</refname>
    <refname>sd_device_get_devname</refname>
    <refname>sd_device_get_devnum</refname>
    <refname>sd_device_get_ifindex</refname>
    <refname>sd_device_get_driver</refname>
    <refname>sd_device_get_diskseq</refname>

    <refpurpose>Returns various fields of device objects</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <funcsynopsis>
      <funcsynopsisinfo>#include &lt;systemd/sd-device.h&gt;</funcsynopsisinfo>

      <funcprototype>
        <funcdef>int <function>sd_device_get_syspath</function></funcdef>
        <paramdef>sd_device *<parameter>device</parameter></paramdef>
        <paramdef>const char **<parameter>ret</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_device_get_devpath</function></funcdef>
        <paramdef>sd_device *<parameter>device</parameter></paramdef>
        <paramdef>const char **<parameter>ret</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_device_get_sysname</function></funcdef>
        <paramdef>sd_device *<parameter>device</parameter></paramdef>
        <paramdef>const char **<parameter>ret</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_device_get_sysnum</function></funcdef>
        <paramdef>sd_device *<parameter>device</parameter></paramdef>
        <paramdef>const char **<parameter>ret</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_device_get_subsystem</function></funcdef>
        <paramdef>sd_device *<parameter>device</parameter></paramdef>
        <paramdef>const char **<parameter>ret</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_device_get_devtype</function></funcdef>
        <paramdef>sd_device *<parameter>device</parameter></paramdef>
        <paramdef>const char **<parameter>ret</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_device_get_devname</function></funcdef>
        <paramdef>sd_device *<parameter>device</parameter></paramdef>
        <paramdef>const char **<parameter>ret</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_device_get_devnum</function></funcdef>
        <paramdef>sd_device *<parameter>device</parameter></paramdef>
        <paramdef>dev_t *<parameter>ret</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_device_get_ifindex</function></funcdef>
        <paramdef>sd_device *<parameter>device</parameter></paramdef>
        <paramdef>int *<parameter>ret</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_device_get_driver</function></funcdef>
        <paramdef>sd_device *<parameter>device</parameter></paramdef>
        <paramdef>const char **<parameter>ret</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_device_get_diskseq</function></funcdef>
        <paramdef>sd_device *<parameter>device</parameter></paramdef>
        <paramdef>uint64_t *<parameter>ret</parameter></paramdef>
      </funcprototype>

    </funcsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><function>sd_device_get_syspath()</function> returns the sysfs path of the specified device record,
    including the <filename>/sys</filename> prefix. Example: <filename>/sys/devices/virtual/tty/tty7</filename></para>

    <para><function>sd_device_get_devpath()</function> returns the sysfs path of the specified device record,
    excluding the <filename>/sys</filename> prefix. Example: <filename>/devices/virtual/tty/tty7</filename></para>

    <para><function>sd_device_get_sysname()</function> returns the sysfs name of the specified device record,
    i.e. the last component of the sysfs path. Example: <literal>tty7</literal> for the device
    <filename>/sys/devices/virtual/tty/tty7</filename></para>

    <para><function>sd_device_get_sysnum()</function> returns the sysfs device number of the specified device
    record, i.e. the numeric suffix of the last component of the sysfs path. Example: <literal>7</literal>
    for the device <filename>/sys/devices/virtual/tty/tty7</filename></para>

    <para><function>sd_device_get_subsystem()</function> returns the kernel subsystem of the specified device
    record. This is a short string fitting into a filename, and thus does not contain a slash and cannot be
    empty. Example: <literal>tty</literal>, <literal>block</literal> or <literal>net</literal>.</para>

    <para><function>sd_device_get_devtype()</function> returns the device type of the specified device
    record, if the subsystem manages multiple types of devices. Example: for devices of the
    <literal>block</literal> subsystem this can be <literal>disk</literal> or <literal>partition</literal>
    </para>

    <para><function>sd_device_get_devname()</function> returns the device node path of the specified device
    record if the device has a device node. Example: for <filename>/sys/devices/virtual/tty/tty7</filename>
    the string <filename>/dev/tty7</filename> is typically returned.</para>

    <para><function>sd_device_get_devnum()</function> returns the device node major/minor
    (i.e. <type>dev_t</type>) of the specified device record if the device has a device node (i.e. the one
    returned by <function>sd_device_get_devname()</function>). For devices belonging to the
    <literal>block</literal> subsystem this refers to a block device node, in all other cases to a character
    device node. Example: for the <filename>/sys/devices/virtual/tty/tty7</filename> device this typically
    returns the device number with major/minor <literal>4:7</literal>.</para>

    <para><function>sd_device_get_ifindex()</function> returns the network interface index of the specified
    device record, if the device encapsulates a network interface device, i.e. belongs to the
    <literal>net</literal> subsystem. Example: the <literal>lo</literal> interface typically has interface
    index 1.</para>

    <para><function>sd_device_get_driver()</function> returns the kernel driver name attached to the
    device. Note that the driver field is set on the devices consumed by the driver, not on the device
    created by it. Example: a PCI device <filename>/sys/bus/pci/devices/0000:00:1f.6</filename> might be
    attached to a driver <literal>e1000e</literal>.</para>

    <para><function>sd_device_get_diskseq()</function> returns the kernel disk sequence number of the block
    device. This number monotonically increases whenever a backing medium of a block device changes without
    the device name changing, and is relevant for block devices encapsulating devices with changing media
    (e.g. floppy or CD-ROM), or loopback block devices. Only defined for block devices, i.e. those of
    subsystem <literal>block</literal>.</para>
  </refsect1>

  <refsect1>
    <title>Return Value</title>

    <para>On success, these calls return 0 or a positive integer. On failure, they return a negative
    errno-style error code.</para>

    <refsect2>
      <title>Errors</title>

      <para>Returned errors may indicate the following problems:</para>

      <variablelist>
        <varlistentry>
          <term><constant>-EINVAL</constant></term>

          <listitem><para>A specified parameter is invalid.</para>

          <xi:include href="version-info.xml" xpointer="v251"/></listitem>
        </varlistentry>

        <varlistentry>
          <term><constant>-ENOENT</constant></term>

          <listitem><para>The requested field is not present in the device record.</para>

          <xi:include href="version-info.xml" xpointer="v251"/></listitem>
        </varlistentry>

      </variablelist>
    </refsect2>
  </refsect1>

  <xi:include href="libsystemd-pkgconfig.xml" />

  <refsect1>
    <title>History</title>
    <para><function>sd_device_get_syspath()</function>,
    <function>sd_device_get_devpath()</function>,
    <function>sd_device_get_sysname()</function>,
    <function>sd_device_get_sysnum()</function>,
    <function>sd_device_get_subsystem()</function>,
    <function>sd_device_get_devtype()</function>,
    <function>sd_device_get_devname()</function>,
    <function>sd_device_get_devnum()</function>,
    <function>sd_device_get_ifindex()</function>,
    <function>sd_device_get_driver()</function>, and
    <function>sd_device_get_diskseq()</function> were added in version 251.</para>
  </refsect1>

  <refsect1>
    <title>See Also</title>

    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>