1 files changed, 163 insertions, 0 deletions
diff --git a/cloudinit/dmi.py b/cloudinit/dmi.py
new file mode 100644
index 00000000..f0e69a5a
--- /dev/null
+++ b/cloudinit/dmi.py
@@ -0,0 +1,163 @@
+# This file is part of cloud-init. See LICENSE file for license information.
+from cloudinit import log as logging
+from cloudinit import subp
+from cloudinit.util import is_container, is_FreeBSD
+
+from collections import namedtuple
+import os
+
+LOG = logging.getLogger(__name__)
+
+# Path for DMI Data
+DMI_SYS_PATH = "/sys/class/dmi/id"
+
+kdmi = namedtuple('KernelNames', ['linux', 'freebsd'])
+kdmi.__new__.defaults__ = (None, None)
+
+# FreeBSD's kenv(1) and Linux /sys/class/dmi/id/* both use different names from
+# dmidecode. The values are the same, and ultimately what we're interested in.
+# These tools offer a "cheaper" way to access those values over dmidecode.
+# This is our canonical translation table. If we add more tools on other
+# platforms to find dmidecode's values, their keys need to be put in here.
+DMIDECODE_TO_KERNEL = {
+    'baseboard-asset-tag': kdmi('board_asset_tag', 'smbios.planar.tag'),
+    'baseboard-manufacturer': kdmi('board_vendor', 'smbios.planar.maker'),
+    'baseboard-product-name': kdmi('board_name', 'smbios.planar.product'),
+    'baseboard-serial-number': kdmi('board_serial', 'smbios.planar.serial'),
+    'baseboard-version': kdmi('board_version', 'smbios.planar.version'),
+    'bios-release-date': kdmi('bios_date', 'smbios.bios.reldate'),
+    'bios-vendor': kdmi('bios_vendor', 'smbios.bios.vendor'),
+    'bios-version': kdmi('bios_version', 'smbios.bios.version'),
+    'chassis-asset-tag': kdmi('chassis_asset_tag', 'smbios.chassis.tag'),
+    'chassis-manufacturer': kdmi('chassis_vendor', 'smbios.chassis.maker'),
+    'chassis-serial-number': kdmi('chassis_serial', 'smbios.chassis.serial'),
+    'chassis-version': kdmi('chassis_version', 'smbios.chassis.version'),
+    'system-manufacturer': kdmi('sys_vendor', 'smbios.system.maker'),
+    'system-product-name': kdmi('product_name', 'smbios.system.product'),
+    'system-serial-number': kdmi('product_serial', 'smbios.system.serial'),
+    'system-uuid': kdmi('product_uuid', 'smbios.system.uuid'),
+    'system-version': kdmi('product_version', 'smbios.system.version'),
+}
+
+
+def _read_dmi_syspath(key):
+    """
+    Reads dmi data from /sys/class/dmi/id
+    """
+    kmap = DMIDECODE_TO_KERNEL.get(key)
+    if kmap is None or kmap.linux is None:
+        return None
+    dmi_key_path = "{0}/{1}".format(DMI_SYS_PATH, kmap.linux)
+    LOG.debug("querying dmi data %s", dmi_key_path)
+    if not os.path.exists(dmi_key_path):
+        LOG.debug("did not find %s", dmi_key_path)
+        return None
+
+    try:
+        with open(dmi_key_path, "rb") as fp:
+            key_data = fp.read()
+    except PermissionError:
+        LOG.debug("Could not read %s", dmi_key_path)
+        return None
+
+    # uninitialized dmi values show as all \xff and /sys appends a '\n'.
+    # in that event, return empty string.
+    if key_data == b'\xff' * (len(key_data) - 1) + b'\n':
+        key_data = b""
+
+    try:
+        return key_data.decode('utf8').strip()
+    except UnicodeDecodeError as e:
+        LOG.error("utf-8 decode of content (%s) in %s failed: %s",
+                  dmi_key_path, key_data, e)
+
+    return None
+
+
+def _read_kenv(key):
+    """
+    Reads dmi data from FreeBSD's kenv(1)
+    """
+    kmap = DMIDECODE_TO_KERNEL.get(key)
+    if kmap is None or kmap.freebsd is None:
+        return None
+
+    LOG.debug("querying dmi data %s", kmap.freebsd)
+
+    try:
+        cmd = ["kenv", "-q", kmap.freebsd]
+        (result, _err) = subp.subp(cmd)
+        result = result.strip()
+        LOG.debug("kenv returned '%s' for '%s'", result, kmap.freebsd)
+        return result
+    except subp.ProcessExecutionError as e:
+        LOG.debug('failed kenv cmd: %s\n%s', cmd, e)
+        return None
+
+    return None
+
+
+def _call_dmidecode(key, dmidecode_path):
+    """
+    Calls out to dmidecode to get the data out. This is mostly for supporting
+    OS's without /sys/class/dmi/id support.
+    """
+    try:
+        cmd = [dmidecode_path, "--string", key]
+        (result, _err) = subp.subp(cmd)
+        result = result.strip()
+        LOG.debug("dmidecode returned '%s' for '%s'", result, key)
+        if result.replace(".", "") == "":
+            return ""
+        return result
+    except subp.ProcessExecutionError as e:
+        LOG.debug('failed dmidecode cmd: %s\n%s', cmd, e)
+        return None
+
+
+def read_dmi_data(key):
+    """
+    Wrapper for reading DMI data.
+
+    If running in a container return None.  This is because DMI data is
+    assumed to be not useful in a container as it does not represent the
+    container but rather the host.
+
+    This will do the following (returning the first that produces a
+    result):
+        1) Use a mapping to translate `key` from dmidecode naming to
+           sysfs naming and look in /sys/class/dmi/... for a value.
+        2) Use `key` as a sysfs key directly and look in /sys/class/dmi/...
+        3) Fall-back to passing `key` to `dmidecode --string`.
+
+    If all of the above fail to find a value, None will be returned.
+    """
+
+    if is_container():
+        return None
+
+    if is_FreeBSD():
+        return _read_kenv(key)
+
+    syspath_value = _read_dmi_syspath(key)
+    if syspath_value is not None:
+        return syspath_value
+
+    def is_x86(arch):
+        return (arch == 'x86_64' or (arch[0] == 'i' and arch[2:] == '86'))
+
+    # running dmidecode can be problematic on some arches (LP: #1243287)
+    uname_arch = os.uname()[4]
+    if not (is_x86(uname_arch) or uname_arch in ('aarch64', 'amd64')):
+        LOG.debug("dmidata is not supported on %s", uname_arch)
+        return None
+
+    dmidecode_path = subp.which('dmidecode')
+    if dmidecode_path:
+        return _call_dmidecode(key, dmidecode_path)
+
+    LOG.warning("did not find either path %s or dmidecode command",
+                DMI_SYS_PATH)
+    return None
+
+# vi: ts=4 expandtab