On Tue, Dec 10, 2024 at 10:28:41AM -0600, Praveen K Paladugu 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
On 12/2/2024 3:46 AM, Purna Pavan Chandra Aekkaladevi wrote: 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