Re: [PATCH 3/6] ch: start a new thread for handling ch events

On 9/19/2024 8:02 AM, Purna Pavan Chandra Aekkaladevi wrote: >Use a FIFO(named pipe) for --event-monitor option in CH. Introduce a new >thread, `virCHEventHandlerLoop`, to continuously monitor and handle >events from cloud-hypervisor. > >Signed-off-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi(a)linux.microsoft.com&gt; >Co-authored-by: Vineeth Pillai <viremana(a)linux.microsoft.com&gt; >--- > po/POTFILES | 1 + > src/ch/ch_events.c | 96 +++++++++++++++++++++++++++++++++++++++++++++ > src/ch/ch_events.h | 26 ++++++++++++ > src/ch/ch_monitor.c | 28 +++++++++++++ > src/ch/ch_monitor.h | 3 ++ > src/ch/meson.build | 2 + > 6 files changed, 156 insertions(+) > create mode 100644 src/ch/ch_events.c > create mode 100644 src/ch/ch_events.h > >diff --git a/po/POTFILES b/po/POTFILES >index 1ed4086d2c..d53307cec4 100644 >--- a/po/POTFILES >+++ b/po/POTFILES >@@ -21,6 +21,7 @@ src/bhyve/bhyve_process.c > src/ch/ch_conf.c > src/ch/ch_domain.c > src/ch/ch_driver.c >+src/ch/ch_events.c > src/ch/ch_interface.c > src/ch/ch_monitor.c > src/ch/ch_process.c >diff --git a/src/ch/ch_events.c b/src/ch/ch_events.c >new file mode 100644 >index 0000000000..851fbc9f26 >--- /dev/null >+++ b/src/ch/ch_events.c >@@ -0,0 +1,96 @@ >+/* >+ * Copyright Microsoft Corp. 2024 >+ * >+ * ch_events.h: Handle Cloud-Hypervisor events please fix the filename here. >+ * >+ * This library is free software; you can redistribute it and/or >+ * modify it under the terms of the GNU Lesser General Public >+ * License as published by the Free Software Foundation; either >+ * version 2.1 of the License, or (at your option) any later version. >+ * >+ * This library 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 >+ * Lesser General Public License for more details. >+ * >+ * You should have received a copy of the GNU Lesser General Public >+ * License along with this library. If not, see >+ * <http://www.gnu.org/licenses/>;. >+ */ >+ >+#include <config.h> >+ >+#include <fcntl.h> >+ >+#include "ch_events.h" >+#include "virfile.h" >+#include "virlog.h" >+ >+VIR_LOG_INIT("ch.ch_events"); >+ >+static void virCHEventHandlerLoop(void *data) >+{ >+ virCHMonitor *mon = data; >+ virDomainObj *vm = NULL; >+ int event_monitor_fd; >+ >+ VIR_DEBUG("Event handler loop thread starting"); >+ >+ while ((event_monitor_fd = open(mon->eventmonitorpath, O_RDONLY)) < 0) { >+ if (errno == EINTR) { >+ g_usleep(100000); // 100 milli seconds >+ continue; >+ } >+ /* >+ * Any other error should be a BUG(kernel/libc/libvirtd) >+ * (ENOMEM can happen on exceeding per-user limits) >+ */ >+ VIR_ERROR(_("Failed to open the event monitor FIFO(%1$s) read end!"), >+ mon->eventmonitorpath); >+ abort(); >+ } >+ VIR_DEBUG("Opened the event monitor FIFO(%s)", mon->eventmonitorpath); >+ >+ /* >+ * We would need to wait until VM is initialized. >+ */ Does this comment apply to next while loop where the events are processed?

>+ while (!(vm = virObjectRef(mon->vm))) >+ g_usleep(100000); // 100 milli seconds In this while loop you are only getting a reference to vm object.

>+ >+ while (g_atomic_int_get(&mon->event_handler_stop) == 0) { >+ VIR_DEBUG("Reading events from event monitor file..."); >+ /* Read and process events here */ >+ } >+ >+ VIR_FORCE_CLOSE(event_monitor_fd); >+ virObjectUnref(vm); >+ >+ VIR_DEBUG("Event handler loop thread exiting"); >+ return; >+} >+ >+int virCHStartEventHandler(virCHMonitor *mon) >+{ >+ g_autofree char *name = NULL; >+ name = g_strdup_printf("event-handler-%d", mon->pid); It would be better to name the thread something similar to "event-handler_ch_${pid}_${vmname}". A similar format is used for cgroup naming. >+ >+ virObjectRef(mon); >+ if (virThreadCreateFull(&mon->event_handler_thread, >+ false, >+ virCHEventHandlerLoop, >+ name, >+ false, >+ mon) < 0) { >+ virObjectUnref(mon); >+ return -1; >+ } >+ virObjectUnref(mon); >+ >+ g_atomic_int_set(&mon->event_handler_stop, 0); >+ return 0; >+} >+ >+void virCHStopEventHandler(virCHMonitor *mon) >+{ >+ g_atomic_int_set(&mon->event_handler_stop, 1); >+} >diff --git a/src/ch/ch_events.h b/src/ch/ch_events.h >new file mode 100644 >index 0000000000..4c8a48231d >--- /dev/null >+++ b/src/ch/ch_events.h >@@ -0,0 +1,26 @@ >+/* >+ * Copyright Microsoft Corp. 2024 >+ * >+ * ch_events.h: header file for handling Cloud-Hypervisor events >+ * >+ * This library is free software; you can redistribute it and/or >+ * modify it under the terms of the GNU Lesser General Public >+ * License as published by the Free Software Foundation; either >+ * version 2.1 of the License, or (at your option) any later version. >+ * >+ * This library 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 >+ * Lesser General Public License for more details. >+ * >+ * You should have received a copy of the GNU Lesser General Public >+ * License along with this library. If not, see >+ * <http://www.gnu.org/licenses/>;. >+ */ >+ >+#pragma once >+ >+#include "ch_monitor.h" >+ >+int virCHStartEventHandler(virCHMonitor *mon); >+void virCHStopEventHandler(virCHMonitor *mon); >diff --git a/src/ch/ch_monitor.c b/src/ch/ch_monitor.c >index 8c99fe1019..5e43bf9ef8 100644 >--- a/src/ch/ch_monitor.c >+++ b/src/ch/ch_monitor.c >@@ -26,6 +26,7 @@ > #include "datatypes.h" > #include "ch_conf.h" >+#include "ch_events.h" > #include "ch_interface.h" > #include "ch_monitor.h" > #include "domain_interface.h" >@@ -572,6 +573,28 @@ virCHMonitorNew(virDomainObj *vm, virCHDriverConfig *cfg) > return NULL; > } >+ /* Event monitor file to listen for VM state changes */ >+ mon->eventmonitorpath = g_strdup_printf("%s/%s-event-monitor-fifo", >+ cfg->stateDir, vm->def->name); >+ if (virFileExists(mon->eventmonitorpath) && >+ !virFileIsNamedPipe(mon->eventmonitorpath)) { >+ VIR_WARN("Monitor file (%s) is not a FIFO, trying to delete!", >+ mon->eventmonitorpath); >+ if (virFileRemove(mon->eventmonitorpath, -1, -1) < 0) { >+ virReportError(VIR_ERR_INTERNAL_ERROR, >+ _("Failed to remove the file: %1$s"), >+ mon->eventmonitorpath); >+ return NULL; >+ } >+ } >+ This does not cover the case when eventmonitorpath exists, and is a named pipe, may be, not cleaned up from a previous run. You are better off just deleting the file and open a new one with mkfifo below. >+ if (mkfifo(mon->eventmonitorpath, S_IWUSR | S_IRUSR) < 0 && >+ errno != EEXIST) { >+ virReportSystemError(errno, "%s", >+ _("Cannot create monitor FIFO")); >+ return NULL; >+ } >+ > cmd = virCommandNew(vm->def->emulator); > virCommandSetUmask(cmd, 0x002); > socket_fd = chMonitorCreateSocket(mon->socketpath); >@@ -593,6 +616,9 @@ virCHMonitorNew(virDomainObj *vm, virCHDriverConfig *cfg) > if (virCommandRunAsync(cmd, &mon->pid) < 0) > return NULL; >+ if (virCHStartEventHandler(mon) < 0) >+ return NULL; >+ > /* get a curl handle */ > mon->handle = curl_easy_init(); >@@ -641,6 +667,8 @@ void virCHMonitorClose(virCHMonitor *mon) > g_free(mon->eventmonitorpath); > } >+ virCHStopEventHandler(mon); >+ Please move virCHStopEventHandler above `if (mon->eventmonitorpath) {` section. Doing so, will allow the event monitor thread to cleanly exit, before you invoke `virFileRemove(mon->eventmonitorpath...`

> virObjectUnref(mon); > } >diff --git a/src/ch/ch_monitor.h b/src/ch/ch_monitor.h >index 2ef8706b99..878a185f29 100644 >--- a/src/ch/ch_monitor.h >+++ b/src/ch/ch_monitor.h >@@ -97,6 +97,9 @@ struct _virCHMonitor { > char *eventmonitorpath; >+ virThread event_handler_thread; >+ int event_handler_stop; >+ > pid_t pid; > virDomainObj *vm; >diff --git a/src/ch/meson.build b/src/ch/meson.build >index 633966aac7..684beac1f2 100644 >--- a/src/ch/meson.build >+++ b/src/ch/meson.build >@@ -7,6 +7,8 @@ ch_driver_sources = [ > 'ch_domain.h', > 'ch_driver.c', > 'ch_driver.h', >+ 'ch_events.c', >+ 'ch_driver.h', > 'ch_interface.c', > 'ch_interface.h', > 'ch_monitor.c', -- Regards, Praveen K Paladugu