Implement `chReadProcessEvents` and `chProcessEvents` to read events from
event monitor FIFO file and parse them accordingly.
Signed-off-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi@linux.microsoft.com>
Co-authored-by: Vineeth Pillai <viremana@linux.microsoft.com>
---
src/ch/ch_events.c | 137 +++++++++++++++++++++++++++++++++++++++++++-
src/ch/ch_events.h | 2 +
src/ch/ch_monitor.h | 6 ++
3 files changed, 144 insertions(+), 1 deletion(-)
diff --git a/src/ch/ch_events.c b/src/ch/ch_events.c
index 247f99cef0..a4c2fc4130 100644
--- a/src/ch/ch_events.c
+++ b/src/ch/ch_events.c
@@ -45,6 +45,137 @@ static int virCHEventStopProcess(virDomainObj *vm,
return 0;
}
+/**
+ * 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));
+ virCHEventStopProcess(vm, VIR_DOMAIN_SHUTOFF_FAILED);
+ virCHStopEventHandler(mon);
+ return;
+ }
+
+ 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;
@@ -56,6 +187,9 @@ static void virCHEventHandlerLoop(void *data)
VIR_DEBUG("%s: Event handler loop thread starting", vm->def->name);
+ mon->event_buffer.buffer = g_malloc_n(sizeof(char), CH_EVENT_BUFFER_SZ);
+ mon->event_buffer.buf_fill_sz = 0;
+
while ((event_monitor_fd = open(mon->eventmonitorpath, O_RDONLY)) < 0) {
if (errno == EINTR) {
/* 100 milli seconds */
@@ -74,10 +208,11 @@ static void virCHEventHandlerLoop(void *data)
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);
}
end:
+ g_clear_pointer(&mon->event_buffer.buffer, g_free);
VIR_FORCE_CLOSE(event_monitor_fd);
virObjectUnref(vm);
VIR_DEBUG("%s: Event handler loop thread exiting", vm->def->name);
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 6d154652fa..a84e348938 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
On 12/2/2024 3:46 AM, Purna Pavan Chandra Aekkaladevi wrote:
> Implement `chReadProcessEvents` and `chProcessEvents` to read events from
> event monitor FIFO file and parse them accordingly.
>
> Signed-off-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi@linux.microsoft.com>
> Co-authored-by: Vineeth Pillai <viremana@linux.microsoft.com>
> ---
> src/ch/ch_events.c | 137 +++++++++++++++++++++++++++++++++++++++++++-
> src/ch/ch_events.h | 2 +
> src/ch/ch_monitor.h | 6 ++
> 3 files changed, 144 insertions(+), 1 deletion(-)
>
> diff --git a/src/ch/ch_events.c b/src/ch/ch_events.c
> index 247f99cef0..a4c2fc4130 100644
> --- a/src/ch/ch_events.c
> +++ b/src/ch/ch_events.c
> @@ -45,6 +45,137 @@ static int virCHEventStopProcess(virDomainObj *vm,
> return 0;
> }
>
> +/**
> + * 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;
If you do encounter an invalid JSON, this implementation will continue
processing rest of the events. You should return from this method with
-1 here.
> + }
> +
> + /* 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));
> + virCHEventStopProcess(vm, VIR_DOMAIN_SHUTOFF_FAILED);
> + virCHStopEventHandler(mon);
> + return;
> + }
> +
> + 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;
> @@ -56,6 +187,9 @@ static void virCHEventHandlerLoop(void *data)
>
> VIR_DEBUG("%s: Event handler loop thread starting", vm->def->name);
>
> + mon->event_buffer.buffer = g_malloc_n(sizeof(char), CH_EVENT_BUFFER_SZ);
> + mon->event_buffer.buf_fill_sz = 0;
> +
> while ((event_monitor_fd = open(mon->eventmonitorpath, O_RDONLY)) < 0) {
> if (errno == EINTR) {
> /* 100 milli seconds */
> @@ -74,10 +208,11 @@ static void virCHEventHandlerLoop(void *data)
>
> 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);
> }
>
> end:
> + g_clear_pointer(&mon->event_buffer.buffer, g_free);
> VIR_FORCE_CLOSE(event_monitor_fd);
> virObjectUnref(vm);
> VIR_DEBUG("%s: Event handler loop thread exiting", vm->def->name);
> 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 6d154652fa..a84e348938 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;
>
--
Regards,
Praveen K Paladugu
On Tue, Dec 10, 2024 at 10:28:41AM -0600, Praveen K Paladugu wrote:
>
>
> On 12/2/2024 3:46 AM, Purna Pavan Chandra Aekkaladevi wrote:
> >Implement `chReadProcessEvents` and `chProcessEvents` to read events from
> >event monitor FIFO file and parse them accordingly.
> >
> >Signed-off-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi@linux.microsoft.com>
> >Co-authored-by: Vineeth Pillai <viremana@linux.microsoft.com>
> >---
> > src/ch/ch_events.c | 137 +++++++++++++++++++++++++++++++++++++++++++-
> > src/ch/ch_events.h | 2 +
> > src/ch/ch_monitor.h | 6 ++
> > 3 files changed, 144 insertions(+), 1 deletion(-)
> >
> >diff --git a/src/ch/ch_events.c b/src/ch/ch_events.c
> >index 247f99cef0..a4c2fc4130 100644
> >--- a/src/ch/ch_events.c
> >+++ b/src/ch/ch_events.c
> >@@ -45,6 +45,137 @@ static int virCHEventStopProcess(virDomainObj *vm,
> > return 0;
> > }
> >+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;
> If you do encounter an invalid JSON, this implementation will continue
> processing rest of the events. You should return from this method with
> -1 here.
>
Returning -1 here does not halt the thread. So, even if we were to
return -1 here (after memmove-ing the rest of the json to the beginning
of buf, just as done in below 'else if' block), it essentially tries to
continue processing the rest of the events.
> >+ }
> >+
> >+ /* 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));
> >+ virCHEventStopProcess(vm, VIR_DOMAIN_SHUTOFF_FAILED);
> >+ virCHStopEventHandler(mon);
> >+ return;
> >+ }
> >+
> >+ 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;
> >+}
> >+
>
> --
> Regards,
> Praveen K Paladugu
Regards,
Purna Pavan Chandra
On 12/11/2024 1:10 AM, Purna Pavan Chandra Aekkaladevi wrote:
> On Tue, Dec 10, 2024 at 10:28:41AM -0600, Praveen K Paladugu wrote:
>>
>>
>> On 12/2/2024 3:46 AM, Purna Pavan Chandra Aekkaladevi wrote:
>>> Implement `chReadProcessEvents` and `chProcessEvents` to read events from
>>> event monitor FIFO file and parse them accordingly.
>>>
>>> Signed-off-by: Purna Pavan Chandra Aekkaladevi <paekkaladevi@linux.microsoft.com>
>>> Co-authored-by: Vineeth Pillai <viremana@linux.microsoft.com>
>>> ---
>>> src/ch/ch_events.c | 137 +++++++++++++++++++++++++++++++++++++++++++-
>>> src/ch/ch_events.h | 2 +
>>> src/ch/ch_monitor.h | 6 ++
>>> 3 files changed, 144 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/src/ch/ch_events.c b/src/ch/ch_events.c
>>> index 247f99cef0..a4c2fc4130 100644
>>> --- a/src/ch/ch_events.c
>>> +++ b/src/ch/ch_events.c
>>> @@ -45,6 +45,137 @@ static int virCHEventStopProcess(virDomainObj *vm,
>>> return 0;
>>> }
>>> +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;
>> If you do encounter an invalid JSON, this implementation will continue
>> processing rest of the events. You should return from this method with
>> -1 here.
>>
>
> Returning -1 here does not halt the thread. So, even if we were to
> return -1 here (after memmove-ing the rest of the json to the beginning
> of buf, just as done in below 'else if' block), it essentially tries to
> continue processing the rest of the events.
That is correct. I should have been clearer.
If aJ JSON event received here is invalid, it is very likely an issue
with the transport. In such a case, following events could also be
corrupt. I don't see much value in processing remaining events in
such a situation.
That is why I am suggesting that you return from this method and stop
processing further events.
>>> + }
>>> +
>>> + /* 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));
>>> + virCHEventStopProcess(vm, VIR_DOMAIN_SHUTOFF_FAILED);
>>> + virCHStopEventHandler(mon);
>>> + return;
>>> + }
>>> +
>>> + 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;
>>> +}
>>> +
>>
>> --
>> Regards,
>> Praveen K Paladugu
>
> Regards,
> Purna Pavan Chandra
--
Regards,
Praveen K Paladugu
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