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@xxxxxxxxxxxxxxxxxxx> Co-authored-by: Vineeth Pillai <viremana@xxxxxxxxxxxxxxxxxxx> --- src/ch/ch_events.c | 78 +++++++++++++++++++++++++++++++++++++++++++++ src/ch/ch_events.h | 26 +++++++++++++++ src/ch/ch_monitor.c | 60 +++++++++++++++++++++++++++++++--- src/ch/ch_monitor.h | 4 +++ src/ch/meson.build | 2 ++ 5 files changed, 166 insertions(+), 4 deletions(-) create mode 100644 src/ch/ch_events.c create mode 100644 src/ch/ch_events.h diff --git a/src/ch/ch_events.c b/src/ch/ch_events.c new file mode 100644 index 0000000000..b6bbce2db0 --- /dev/null +++ b/src/ch/ch_events.c @@ -0,0 +1,78 @@ +/* + * Copyright Microsoft Corp. 2024 + * + * ch_events.c: 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_domain.h" +#include "ch_events.h" +#include "ch_process.h" +#include "virfile.h" +#include "virlog.h" + +VIR_LOG_INIT("ch.ch_events"); + + +static void virCHEventHandlerLoop(void *data) +{ + virCHMonitor *mon = data; + virDomainObj *vm = NULL; + + /* Obtain a vm reference */ + vm = virObjectRef(mon->vm); + + VIR_DEBUG("%s: Event handler loop thread starting", vm->def->name); + + while (g_atomic_int_get(&mon->event_handler_stop) == 0) { + VIR_DEBUG("%s: Reading events from event monitor file", vm->def->name); + /* Read and process events here */ + } + + virObjectUnref(vm); + VIR_DEBUG("%s: Event handler loop thread exiting", vm->def->name); + return; +} + +int virCHStartEventHandler(virCHMonitor *mon) +{ + g_autofree char *name = NULL; + name = g_strdup_printf("ch-evt-%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 a72ee40aa1..bedcde2dde 100644 --- a/src/ch/ch_monitor.c +++ b/src/ch/ch_monitor.c @@ -20,12 +20,14 @@ #include <config.h> +#include <fcntl.h> #include <stdio.h> #include <unistd.h> #include <curl/curl.h> #include "datatypes.h" #include "ch_conf.h" +#include "ch_events.h" #include "ch_interface.h" #include "ch_monitor.h" #include "domain_interface.h" @@ -542,6 +544,7 @@ virCHMonitorNew(virDomainObj *vm, virCHDriverConfig *cfg, int logfile) g_autoptr(virCHMonitor) mon = NULL; g_autoptr(virCommand) cmd = NULL; int socket_fd = 0; + int event_monitor_fd; if (virCHMonitorInitialize() < 0) return NULL; @@ -549,6 +552,9 @@ virCHMonitorNew(virDomainObj *vm, virCHDriverConfig *cfg, int logfile) if (!(mon = virObjectLockableNew(virCHMonitorClass))) return NULL; + /* avoid VIR_FORCE_CLOSE()-ing garbage fd value in virCHMonitorClose */ + mon->eventmonitorfd = -1; + if (!vm->def) { virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("VM is not defined")); @@ -557,8 +563,6 @@ virCHMonitorNew(virDomainObj *vm, virCHDriverConfig *cfg, int logfile) /* prepare to launch Cloud-Hypervisor socket */ mon->socketpath = g_strdup_printf("%s/%s-socket", cfg->stateDir, vm->def->name); - mon->eventmonitorpath = g_strdup_printf("%s/%s-event-monitor", - cfg->stateDir, vm->def->name); if (g_mkdir_with_parents(cfg->stateDir, 0777) < 0) { virReportSystemError(errno, _("Cannot create socket directory '%1$s'"), @@ -573,6 +577,27 @@ virCHMonitorNew(virDomainObj *vm, virCHDriverConfig *cfg, int logfile) return NULL; } + /* Event monitor file to listen for VM state changes */ + mon->eventmonitorpath = g_strdup_printf("%s/%s-event-monitor-fifo", + cfg->stateDir, vm->def->name); + if (virFileExists(mon->eventmonitorpath)) { + VIR_WARN("Monitor file (%s) already exists, trying to delete!", + mon->eventmonitorpath); + if (virFileRemove(mon->eventmonitorpath, -1, -1) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Failed to remove the file: %1$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; + } + cmd = virCommandNew(vm->def->emulator); virCommandSetOutputFD(cmd, &logfile); virCommandSetErrorFD(cmd, &logfile); @@ -597,12 +622,35 @@ virCHMonitorNew(virDomainObj *vm, virCHDriverConfig *cfg, int logfile) if (virCommandRunAsync(cmd, &mon->pid) < 0) return NULL; - /* get a curl handle */ - mon->handle = curl_easy_init(); + /* open the reader end of fifo before start Event Handler */ + while ((event_monitor_fd = open(mon->eventmonitorpath, O_RDONLY)) < 0) { + if (errno == EINTR) { + /* 100 milli seconds */ + g_usleep(100000); + continue; + } + /* Any other error should be a BUG(kernel/libc/libvirtd) + * (ENOMEM can happen on exceeding per-user limits) + */ + VIR_ERROR(_("%1$s: Failed to open the event monitor FIFO(%2$s) read end!"), + vm->def->name, mon->eventmonitorpath); + /* CH process(Writer) is blocked at this point as EventHandler(Reader) + * fails to open the FIFO. + */ + return NULL; + } + mon->eventmonitorfd = event_monitor_fd; + VIR_DEBUG("%s: Opened the event monitor FIFO(%s)", vm->def->name, mon->eventmonitorpath); /* now has its own reference */ mon->vm = virObjectRef(vm); + if (virCHStartEventHandler(mon) < 0) + return NULL; + + /* get a curl handle */ + mon->handle = curl_easy_init(); + return g_steal_pointer(&mon); } @@ -638,6 +686,10 @@ void virCHMonitorClose(virCHMonitor *mon) g_clear_pointer(&mon->socketpath, g_free); } + virCHStopEventHandler(mon); + if (mon->eventmonitorfd >= 0) { + VIR_FORCE_CLOSE(mon->eventmonitorfd); + } if (mon->eventmonitorpath) { if (virFileRemove(mon->eventmonitorpath, -1, -1) < 0) { VIR_WARN("Unable to remove CH event monitor file '%s'", diff --git a/src/ch/ch_monitor.h b/src/ch/ch_monitor.h index 67dc54f9f4..b9092f22b8 100644 --- a/src/ch/ch_monitor.h +++ b/src/ch/ch_monitor.h @@ -97,6 +97,10 @@ struct _virCHMonitor { char *socketpath; char *eventmonitorpath; + int eventmonitorfd; + + virThread event_handler_thread; + int event_handler_stop; pid_t pid; diff --git a/src/ch/meson.build b/src/ch/meson.build index ca1291c158..0b4a5aeb49 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_events.h', 'ch_interface.c', 'ch_interface.h', 'ch_monitor.c', -- 2.34.1
