hooks: Add log-firmware

This is a combination of the interface of log-console and the
functionality of qemucmdline, hard-coded to log the firmware output to a
log file. qemucmdline can't be used directly for HostedEngine, because
we want a separate log file per VM, and qemucmdline does not have
internally functionality to allow doing that, relying instead on the
engine to supply correct params somehow. For HostedEngine, we can't rely
on the engine, as it does not exist at this point.

Change-Id: I5e2324009daed5136ab7884226cce0feee2e0c96
Signed-off-by: Yedidyah Bar David <[email protected]>

configure.ac

@@ -402,6 +402,7 @@ AC_OUTPUT([
 	vdsm_hooks/httpsisoboot/Makefile
 	vdsm_hooks/localdisk/Makefile
 	vdsm_hooks/log_console/Makefile
+	vdsm_hooks/log_firmware/Makefile
 	vdsm_hooks/macbind/Makefile
 	vdsm_hooks/nestedvt/Makefile
 	vdsm_hooks/openstacknet/Makefile

execcmd-allowlist.txt

@@ -32,6 +32,7 @@ vdsm_hooks/fcoe/fcoe_before_network_setup.py
 vdsm_hooks/localdisk/after_disk_prepare
 vdsm_hooks/localdisk/localdisk-helper
 vdsm_hooks/log_console/before_vm_start.py
+vdsm_hooks/log_firmware/before_vm_start.py
 vdsm_hooks/openstacknet/after_get_caps.py
 vdsm_hooks/openstacknet/openstacknet_utils.py
 vdsm_hooks/scratchpad/before_vm_start.py

vdsm.spec.in

@@ -507,6 +507,14 @@ Requires:       %{name}
 %description hook-log-console
 This hook allows logging a VM serial console to a file.
 
+%package hook-log-firmware
+Summary:        Log VM's firmware to a file
+BuildArch:      noarch
+Requires:       %{name}
+
+%description hook-log-firmware
+This hook allows logging a VM firmware to a file.
+
 %package hook-macbind
 Summary:        Bind a vNIC to a Bridge
 BuildArch:      noarch
@@ -1061,6 +1069,9 @@ exit 0
 %files hook-log-console
 %{_libexecdir}/%{vdsm_name}/hooks/before_vm_start/50_log_console
 
+%files hook-log-firmware
+%{_libexecdir}/%{vdsm_name}/hooks/before_vm_start/50_log_firmware
+
 %files hook-vmfex-dev
 %{_libexecdir}/%{vdsm_name}/hooks/before_device_create/50_vmfex
 %{_libexecdir}/%{vdsm_name}/hooks/before_device_migrate_destination/50_vmfex

vdsm_hooks/Makefile.am

@@ -25,6 +25,7 @@ SUBDIRS = \
 	fcoe \
 	localdisk \
 	log_console \
+	log_firmware \
 	openstacknet \
 	qemucmdline \
 	vhostmd \

vdsm_hooks/log_firmware/Makefile.am

@@ -0,0 +1,31 @@
+#
+# Copyright 2022 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+#
+# Refer to the README and COPYING files for full details of the license
+#
+
+EXTRA_DIST = \
+	before_vm_start.py
+
+install-data-local:
+	$(MKDIR_P) $(DESTDIR)$(vdsmhooksdir)/before_vm_start
+	$(INSTALL_SCRIPT) $(srcdir)/before_vm_start.py \
+		$(DESTDIR)$(vdsmhooksdir)/before_vm_start/50_log_firmware
+
+uninstall-local:
+	$(RM) $(DESTDIR)$(vdsmhooksdir)/before_vm_start/50_log_firmware
+

vdsm_hooks/log_firmware/README

@@ -0,0 +1,51 @@
+log_firmware vdsm hook
+=================================
+This hook appends a VM's firmware debug logging to a log file on the host.
+
+Installation:
+* Use engine-config to set the appropriate custom properties as such:
+
+Custom property for a VM:
+    sudo engine-config -s "UserDefinedVMProperties=log_firmware=^(on|off)$"
+
+* Prepare the log directory on the host:
+    sudo mkdir -p /var/log/qemu-firmware
+    sudo chown qemu /var/log/qemu-firmware
+    sudo chcon -t qemu_var_run_t /var/log/qemu-firmware
+    sudo chmod 700 /var/log/qemu-firmware
+
+Usage:
+
+The hook can be enabled using one of two ways:
+
+1. Set the VM property 'log_firmware' to 'on', for specific VMs, as needed, via
+the engine. Set it to 'off', to explicitly disable the hook.
+
+2. Set the environment variable 'log_firmware_vm_regexp', in
+/etc/sysconfig/vdsm, to a regular expression matching the VM names for which
+you want to enable the hook. Matching is done using Python's re.match().
+
+If log_firmware is set to 'off', for some VM, the hook will be disabled,
+regardless of the value of log_firmware_vm_regexp or whether the name matches.
+
+If 'log_firmware' is not 'on', for some VM, and 'log_firmware_vm_regexp' does
+not match, the hook will be disabled. So by default, with both variables
+being empty/unset, the hook is disabled.
+
+In principle, a future version might enable it by default, based on feedback
+from users.
+
+Using log_firmware_vm_regexp is useful, in particular, for enabling the hook
+for a HostedEngine VM, for which using 'log_firmware' is less practical, as
+the engine might be down exactly when you want to use it (to help diagnose
+why it's down...).
+
+The logs are written to the directory set with the environment variable
+log_firmware_dir, or to /var/log/qemu-firmware if it's not set.
+If you do set it, you should prepare the directory as detailed above.
+The logs' filenames, inside this directory, are {vm_name}-firmware.log,
+where {vm_name} is replaced with the VM's name.
+
+TODO: I'd like to be able to be able to write log files to
+/var/log/libvirt/qemu, like other logs, but that's not easy.
+See also: https://gerrit.ovirt.org/c/lago-ost/+/114150

vdsm_hooks/log_firmware/before_vm_start.py

@@ -0,0 +1,90 @@
+#!/usr/bin/python3
+#
+# Copyright 2022 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+#
+# Refer to the README and COPYING files for full details of the license
+#
+
+import os
+import re
+import traceback
+
+from vdsm.hook import hooking
+
+
+def main():
+    log_firmware = os.environ.get('log_firmware')
+    hooking.log(f'log_firmware: "{log_firmware}"')
+    if log_firmware == 'off':
+        return
+
+    log_firmware_vm_regexp = os.environ.get('log_firmware_vm_regexp')
+    hooking.log(f'log_firmware_vm_regexp: "{log_firmware_vm_regexp}"')
+
+    domxml = hooking.read_domxml()
+    vm_name = domxml.getElementsByTagName('name')[0].firstChild.data
+    hooking.log(f'vm_name: {vm_name}')
+
+    if (
+        log_firmware != 'on'
+        and (
+            not log_firmware_vm_regexp
+            or not re.match(log_firmware_vm_regexp, vm_name)
+        )
+    ):
+        return
+
+    domain = domxml.getElementsByTagName('domain')[0]
+
+    domain.setAttribute(
+        'xmlns:qemu',
+        'http://libvirt.org/schemas/domain/qemu/1.0'
+    )
+
+    qemucl = domxml.createElement('qemu:commandline')
+
+    log_dir = os.environ.get(
+        'log_firmware_dir',
+        '/var/log/qemu-firmware'
+    )
+    for arg in (
+        '-chardev',
+        f'file,id=firmware,path={log_dir}/{vm_name}-firmware.log',
+        '-device',
+        'isa-debugcon,iobase=0x402,chardev=firmware',
+    ):
+        argelement = domxml.createElement('qemu:arg')
+        argelement.setAttribute('value', arg)
+        qemucl.appendChild(argelement)
+
+    domain.appendChild(qemucl)
+    hooking.log(f'qemucl: [{qemucl.toprettyxml()}]')
+
+    hooking.log(f'domxml: [{domxml.toprettyxml()}]')
+    hooking.write_domxml(domxml)
+
+
+if __name__ == '__main__':
+    try:
+        main()
+    except:
+        hooking.exit_hook(
+            'log_firmware: %s' % (
+                traceback.format_exc()
+            ),
+            return_code=1
+        )