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@xxxxxxxxxxxxxxxxxxx> Co-authored-by: Vineeth Pillai <viremana@xxxxxxxxxxxxxxxxxxx> --- 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
