The `--event-monitor` option in cloud-hypervisor outputs events to a specified file. This file can then be used to monitor VM lifecycle, other vmm events and trigger appropriate actions. Signed-off-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi(a)linux.microsoft.com&gt; Co-authored-by: Vineeth Pillai <viremana(a)linux.microsoft.com&gt; --- src/ch/ch_monitor.c | 20 ++++++++++++++++---- src/ch/ch_monitor.h | 2 ++ 2 files changed, 18 insertions(+), 4 deletions(-) diff --git a/src/ch/ch_monitor.c b/src/ch/ch_monitor.c index 3e49902791..21a9ee273e 100644 --- a/src/ch/ch_monitor.c +++ b/src/ch/ch_monitor.c @@ -540,7 +540,6 @@ virCHMonitorNew(virDomainObj *vm, virCHDriverConfig *cfg) { g_autoptr(virCHMonitor) mon = NULL; g_autoptr(virCommand) cmd = NULL; - const char *socketdir = cfg->stateDir; int socket_fd = 0; if (virCHMonitorInitialize() < 0) @@ -556,11 +555,13 @@ virCHMonitorNew(virDomainObj *vm, virCHDriverConfig *cfg) } /* prepare to launch Cloud-Hypervisor socket */ - mon->socketpath = g_strdup_printf("%s/%s-socket", socketdir, vm->def->name); - if (g_mkdir_with_parents(socketdir, 0777) < 0) { + 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'"), - socketdir); + cfg->stateDir); return NULL; } @@ -585,6 +586,9 @@ virCHMonitorNew(virDomainObj *vm, virCHDriverConfig *cfg) virCommandAddArgFormat(cmd, "fd=%d", socket_fd); virCommandPassFD(cmd, socket_fd, VIR_COMMAND_PASS_FD_CLOSE_PARENT); + virCommandAddArg(cmd, "--event-monitor"); + virCommandAddArgFormat(cmd, "path=%s", mon->eventmonitorpath); + /* launch Cloud-Hypervisor socket */ if (virCommandRunAsync(cmd, &mon->pid) < 0) return NULL; @@ -629,6 +633,14 @@ void virCHMonitorClose(virCHMonitor *mon) g_free(mon->socketpath); } + if (virFileExists(mon->eventmonitorpath)) { + if (virFileRemove(mon->eventmonitorpath, -1, -1) < 0) { + VIR_WARN("Unable to remove CH event monitor file '%s'", + mon->eventmonitorpath); + } + g_free(mon->eventmonitorpath); + } + virObjectUnref(mon); } diff --git a/src/ch/ch_monitor.h b/src/ch/ch_monitor.h index b35f5ea027..2ef8706b99 100644 --- a/src/ch/ch_monitor.h +++ b/src/ch/ch_monitor.h @@ -95,6 +95,8 @@ struct _virCHMonitor { char *socketpath; + char *eventmonitorpath; + pid_t pid; virDomainObj *vm; -- 2.34.1

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 | 93 +++++++++++++++++++++++++++++++++++++++++++++ src/ch/ch_events.h | 26 +++++++++++++ src/ch/ch_monitor.c | 32 ++++++++++++++-- src/ch/ch_monitor.h | 3 ++ src/ch/meson.build | 2 + 6 files changed, 154 insertions(+), 3 deletions(-) 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..bb27f340e2 --- /dev/null +++ b/src/ch/ch_events.c @@ -0,0 +1,93 @@ +/* + * 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_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; + + /* Obtain a vm reference */ + vm = virObjectRef(mon->vm); + + VIR_DEBUG("%s: Event handler loop thread starting", vm->def->name); + + 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); + abort(); + } + VIR_DEBUG("%s: Opened the event monitor FIFO(%s)", vm->def->name, mon->eventmonitorpath); + + 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 */ + } + + VIR_FORCE_CLOSE(event_monitor_fd); + 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 21a9ee273e..097e64d9d5 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 +573,27 @@ 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)) { + 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); virCommandSetUmask(cmd, 0x002); socket_fd = chMonitorCreateSocket(mon->socketpath); @@ -593,12 +615,15 @@ virCHMonitorNew(virDomainObj *vm, virCHDriverConfig *cfg) if (virCommandRunAsync(cmd, &mon->pid) < 0) return NULL; - /* get a curl handle */ - mon->handle = curl_easy_init(); - /* 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); } @@ -633,6 +658,7 @@ void virCHMonitorClose(virCHMonitor *mon) g_free(mon->socketpath); } + virCHStopEventHandler(mon); if (virFileExists(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 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..77bbb2d450 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

Implement `chReadProcessEvents` and `chProcessEvents` to read events from event monitor FIFO file and parse them accordingly. Signed-off-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi(a)linux.microsoft.com&gt; Co-authored-by: Vineeth Pillai <viremana(a)linux.microsoft.com&gt; --- src/ch/ch_events.c | 136 +++++++++++++++++++++++++++++++++++++++++++- src/ch/ch_events.h | 2 + src/ch/ch_monitor.h | 6 ++ 3 files changed, 143 insertions(+), 1 deletion(-) diff --git a/src/ch/ch_events.c b/src/ch/ch_events.c index bb27f340e2..d0ad5af0af 100644 --- a/src/ch/ch_events.c +++ b/src/ch/ch_events.c @@ -28,6 +28,136 @@ VIR_LOG_INIT("ch.ch_events"); +/** + * virCHProcessEvents: + * @mon: the CH monitor object + * + * Parse the events from the event buffer and process them + * Example event: + * { + * "timestamp": { + * "secs": 0, + * "nanos": 29228206 + * }, + * "source": "vm", + * "event": "booted", + * "properties": null + * } + * + * Returns: 0 on success, -1 on failure + */ +static int virCHProcessEvents(virCHMonitor *mon) +{ + virDomainObj *vm = mon->vm; + char *buf = mon->event_buffer.buffer; + ssize_t sz = mon->event_buffer.buf_fill_sz; + virJSONValue *obj = NULL; + int blocks = 0; + size_t i = 0; + char *json_start; + ssize_t start_index = -1; + ssize_t end_index = -1; + char tmp; + int ret = 0; + + while (i < sz) { + if (buf[i] == '{') { + blocks++; + if (blocks == 1) + start_index = i; + } else if (buf[i] == '}' && blocks > 0) { + blocks--; + if (blocks == 0) { + /* valid json document */ + end_index = i; + + /* temporarily null terminate the JSON doc */ + tmp = buf[end_index + 1]; + buf[end_index + 1] = '\0'; + json_start = buf + start_index; + + if ((obj = virJSONValueFromString(json_start))) { + /* Process the event string (obj) here */ + virJSONValueFree(obj); + } else { + VIR_WARN("%s: Invalid JSON event doc: %s", + vm->def->name, json_start); + ret = -1; + } + + /* replace the original character */ + buf[end_index + 1] = tmp; + start_index = -1; + } + } + + i++; + } + + if (start_index == -1) { + /* We have processed all the JSON docs in the buffer */ + mon->event_buffer.buf_fill_sz = 0; + } else if (start_index > 0) { + /* We have an incomplete JSON doc at the end of the buffer + * Move it to the start of the buffer + */ + mon->event_buffer.buf_fill_sz = sz - start_index; + memmove(buf, buf+start_index, mon->event_buffer.buf_fill_sz); + } + + return ret; +} + +static void virCHReadProcessEvents(virCHMonitor *mon, + int event_monitor_fd) +{ + /* Event json string must always terminate with null char. + * So, reserve one byte for '\0' at the end. + */ + size_t max_sz = CH_EVENT_BUFFER_SZ - 1; + char *buf = mon->event_buffer.buffer; + virDomainObj *vm = mon->vm; + bool incomplete = false; + size_t sz = 0; + + memset(buf, 0, max_sz); + do { + ssize_t ret; + + ret = read(event_monitor_fd, buf + sz, max_sz - sz); + if (ret == 0 || (ret < 0 && errno == EINTR)) { + g_usleep(G_USEC_PER_SEC); + continue; + } else if (ret < 0) { + /* We should never reach here. read(2) says possible errors + * are EINTR, EAGAIN, EBADF, EFAULT, EINVAL, EIO, EISDIR + * We handle EINTR gracefully. There is some serious issue + * if we encounter any of the other errors(either in our code + * or in the system). Better to bail out. + */ + VIR_ERROR(_("%1$s: Failed to read ch events!: %2$s"), + vm->def->name, g_strerror(errno)); + VIR_FORCE_CLOSE(event_monitor_fd); + abort(); + } + + sz += ret; + mon->event_buffer.buf_fill_sz = sz; + + if (virCHProcessEvents(mon) < 0) + VIR_WARN("%s: Failed to parse and process events", vm->def->name); + + if (mon->event_buffer.buf_fill_sz != 0) + incomplete = true; + else + incomplete = false; + sz = mon->event_buffer.buf_fill_sz; + + } while (virDomainObjIsActive(vm) && (sz < max_sz) && incomplete); + + return; +} + static void virCHEventHandlerLoop(void *data) { virCHMonitor *mon = data; @@ -54,11 +184,15 @@ static void virCHEventHandlerLoop(void *data) } VIR_DEBUG("%s: Opened the event monitor FIFO(%s)", vm->def->name, mon->eventmonitorpath); + mon->event_buffer.buffer = g_malloc_n(sizeof(char), CH_EVENT_BUFFER_SZ); + mon->event_buffer.buf_fill_sz = 0; + 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 */ + virCHReadProcessEvents(mon, event_monitor_fd); } + g_free(mon->event_buffer.buffer); VIR_FORCE_CLOSE(event_monitor_fd); virObjectUnref(vm); diff --git a/src/ch/ch_events.h b/src/ch/ch_events.h index 4c8a48231d..2e9cdf03bb 100644 --- a/src/ch/ch_events.h +++ b/src/ch/ch_events.h @@ -22,5 +22,7 @@ #include "ch_monitor.h" +#define CH_EVENT_BUFFER_SZ PIPE_BUF + int virCHStartEventHandler(virCHMonitor *mon); void virCHStopEventHandler(virCHMonitor *mon); diff --git a/src/ch/ch_monitor.h b/src/ch/ch_monitor.h index 878a185f29..d31b924d0e 100644 --- a/src/ch/ch_monitor.h +++ b/src/ch/ch_monitor.h @@ -99,6 +99,12 @@ struct _virCHMonitor { virThread event_handler_thread; int event_handler_stop; + struct { + /* Buffer to hold the data read from pipe */ + char *buffer; + /* Size of the data read from pipe into buffer */ + size_t buf_fill_sz; + } event_buffer; pid_t pid; -- 2.34.1

Thanks for the review, Michal. I will add your suggestion to not abort() and fix the possible memory leak issue in V4. On Mon, Nov 11, 2024 at 02:37:00PM +0100, Michal Prívozník wrote: Sure, will use saferead(). Yes, event_monitor_fd is in blocking mode and it might seem like this loop is not required. But we could end up read()-ing a partial event json; a loop here makes it possible to read the rest of the json ... ... and the loop is run only when the read() event json is incomplete. Regards, Pavan

Signed-off-by: Purna Pavan Chandra <paekkaladevi(a)linux.microsoft.com&gt; Signed-off-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi(a)linux.microsoft.com&gt; --- NEWS.rst | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/NEWS.rst b/NEWS.rst index 56adf8df8b..7bf8dcc085 100644 --- a/NEWS.rst +++ b/NEWS.rst @@ -28,6 +28,13 @@ v10.9.0 (unreleased) for ``virsh migrate`` or ``VIR_MIGRATE_PARAM_MIGRATE_DISKS_DETECT_ZEROES`` migration parameter. See the documentation for caveats. + * ch: Support handling events from cloud-hypervisor + + The ch driver now supports handling events from the cloud-hypervisor. + Events include VM lifecyle operations such as shutdown, pause, resume, + etc. Libvirt will now read these events and take actions such as + updating domain state, etc. + * **Improvements** * qemu: internal snapshot improvements -- 2.34.1