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 > + * > + * 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. > + */ > + while (!(vm = virObjectRef(mon->vm))) > + g_usleep(100000); // 100 milli seconds > + > + 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); > + > + 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; > + } > + } > + > + if (mkfifo(mon->eventmonitorpath, S_IWUSR | S_IRUSR) < 0 && > + errno != EEXIST) { > + virReportSystemError(errno, "%s", > + _("Cannot create monitor FIFO")); > + return NULL; > + } Why do you need to create a pipe here as instead of opening the file at eventmonitorpath, after cloud-hypervisor starts?

> + > 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); > + > 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