Fix: UST comm protocol: event notifier command is too large

The event notifier command is larger than the current largest command,
and we don't want to break the protocol between UST and tools
needlessly.

Therefore, pass the struct lttng_ust_event_notifier _after_ struct
ustcomm_ust_msg.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Change-Id: Ief172eaddd113ec9092dd57bad3d73fd4c29fd51

diff --git a/include/ust-comm.h b/include/ust-comm.h
index 49a55d2109e31b6ceca45a8fc09002b2f0e45220..c59003687e64601c565d86f738d82e0962a3ba45 100644 (file)
--- a/include/ust-comm.h
+++ b/include/ust-comm.h
@@ -88,7 +88,6 @@ struct ustcomm_ust_msg {
        uint32_t cmd;
        char padding[USTCOMM_MSG_PADDING1];
        union {
-               struct lttng_ust_event_notifier event_notifier;
                struct lttng_ust_channel channel;
                struct lttng_ust_stream stream;
                struct lttng_ust_event event;
@@ -111,6 +110,15 @@ struct ustcomm_ust_msg {
                struct lttng_ust_counter counter;
                struct lttng_ust_counter_global counter_global;
                struct lttng_ust_counter_cpu counter_cpu;
+               /*
+                * For LTTNG_UST_EVENT_NOTIFIER_CREATE, a struct
+                * lttng_ust_event_notifier implicitly follows struct
+                * ustcomm_ust_msg.
+                */
+               struct {
+                       /* Length of struct lttng_ust_event_notifier */
+                       uint32_t len;
+               } event_notifier;
                char padding[USTCOMM_MSG_PADDING2];
        } u;
 } LTTNG_PACKED;

diff --git a/liblttng-ust-ctl/ustctl.c b/liblttng-ust-ctl/ustctl.c
index 7d2c05a9a9edb7002bbc28aae4daa9f3767945aa..07267aed122ff469591b3062f628d5ecbfbbe89a 100644 (file)
--- a/liblttng-ust-ctl/ustctl.c
+++ b/liblttng-ust-ctl/ustctl.c
@@ -562,6 +562,7 @@ int ustctl_create_event_notifier(int sock, struct lttng_ust_event_notifier *even
        struct ustcomm_ust_msg lum;
        struct ustcomm_ust_reply lur;
        struct lttng_ust_object_data *event_notifier_data;
+       ssize_t len;
        int ret;
 
        if (!event_notifier_group || !_event_notifier_data)
@@ -576,19 +577,21 @@ int ustctl_create_event_notifier(int sock, struct lttng_ust_event_notifier *even
        memset(&lum, 0, sizeof(lum));
        lum.handle = event_notifier_group->handle;
        lum.cmd = LTTNG_UST_EVENT_NOTIFIER_CREATE;
+       lum.u.event_notifier.len = sizeof(*event_notifier);
 
-       strncpy(lum.u.event_notifier.event.name, event_notifier->event.name,
-               LTTNG_UST_SYM_NAME_LEN);
-       lum.u.event_notifier.event.instrumentation = event_notifier->event.instrumentation;
-       lum.u.event_notifier.event.loglevel_type = event_notifier->event.loglevel_type;
-       lum.u.event_notifier.event.loglevel = event_notifier->event.loglevel;
-       lum.u.event_notifier.event.token = event_notifier->event.token;
-       lum.u.event_notifier.error_counter_index = event_notifier->error_counter_index;
        ret = ustcomm_send_app_cmd(sock, &lum, &lur);
        if (ret) {
                free(event_notifier_data);
                return ret;
        }
+       /* Send struct lttng_ust_event_notifier */
+       len = ustcomm_send_unix_sock(sock, event_notifier, sizeof(*event_notifier));
+       if (len != sizeof(*event_notifier)) {
+               if (len < 0)
+                       return len;
+               else
+                       return -EIO;
+       }
        event_notifier_data->handle = lur.ret_val;
        DBG("received event_notifier handle %u", event_notifier_data->handle);
        *_event_notifier_data = event_notifier_data;

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index bb22a8a9d8af068de6b77145c5ca61fe228e9f90..59f14050f1b5dfdd4d53dc73d3730d9387a96142 100644 (file)
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -1216,6 +1216,48 @@ int handle_message(struct sock_info *sock_info,
                        ret = -ENOSYS;
                break;
        }
+       case LTTNG_UST_EVENT_NOTIFIER_CREATE:
+       {
+               /* Receive struct lttng_ust_event_notifier */
+               struct lttng_ust_event_notifier event_notifier;
+
+               if (sizeof(event_notifier) != lum->u.event_notifier.len) {
+                       DBG("incorrect event notifier data message size: %u", lum->u.event_notifier.len);
+                       ret = -EINVAL;
+                       goto error;
+               }
+               len = ustcomm_recv_unix_sock(sock, &event_notifier, sizeof(event_notifier));
+               switch (len) {
+               case 0: /* orderly shutdown */
+                       ret = 0;
+                       goto error;
+               default:
+                       if (len == sizeof(event_notifier)) {
+                               DBG("event notifier data received");
+                               break;
+                       } else if (len < 0) {
+                               DBG("Receive failed from lttng-sessiond with errno %d", (int) -len);
+                               if (len == -ECONNRESET) {
+                                       ERR("%s remote end closed connection", sock_info->name);
+                                       ret = len;
+                                       goto error;
+                               }
+                               ret = len;
+                               goto error;
+                       } else {
+                               DBG("incorrect event notifier data message size: %zd", len);
+                               ret = -EINVAL;
+                               goto error;
+                       }
+               }
+               if (ops->cmd)
+                       ret = ops->cmd(lum->handle, lum->cmd,
+                                       (unsigned long) &event_notifier,
+                                       &args, sock_info);
+               else
+                       ret = -ENOSYS;
+               break;
+       }
 
        default:
                if (ops->cmd)