Refactor setup_lttng_msg() to include cmd header
authorPhilippe Proulx <eeppeliteloop@gmail.com>
Fri, 28 Aug 2015 17:34:54 +0000 (13:34 -0400)
committerJérémie Galarneau <jeremie.galarneau@efficios.com>
Thu, 25 Feb 2016 21:52:54 +0000 (16:52 -0500)
setup_lttng_msg_full() is now responsible for memcpy()ing
the command header and payload to the complete message.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
src/bin/lttng-sessiond/main.c
src/common/sessiond-comm/sessiond-comm.h

index c8989113a2e9b701f460b92ad189b7e2a3b60189..545f456e912f6a62bb76cc265350dc9369a7e3e1 100644 (file)
@@ -871,34 +871,53 @@ error:
  * right amount of memory and copying the original information from the lsm
  * structure.
  *
- * Return total size of the buffer pointed by buf.
+ * Return 0 on success, negative value on error.
  */
-static int setup_lttng_msg(struct command_ctx *cmd_ctx, size_t size)
+static int setup_lttng_msg(struct command_ctx *cmd_ctx,
+       const void *payload_buf, size_t payload_len,
+       const void *cmd_header_buf, size_t cmd_header_len)
 {
-       int ret, buf_size;
+       int ret = 0;
+       const size_t header_len = sizeof(struct lttcomm_lttng_msg);
+       const size_t cmd_header_offset = header_len;
+       const size_t payload_offset = cmd_header_offset + cmd_header_len;
+       const size_t total_msg_size = header_len + cmd_header_len + payload_len;
 
-       buf_size = size;
+       cmd_ctx->llm = zmalloc(total_msg_size);
 
-       cmd_ctx->llm = zmalloc(sizeof(struct lttcomm_lttng_msg) + buf_size);
        if (cmd_ctx->llm == NULL) {
                PERROR("zmalloc");
                ret = -ENOMEM;
-               goto error;
+               goto end;
        }
 
        /* Copy common data */
        cmd_ctx->llm->cmd_type = cmd_ctx->lsm->cmd_type;
        cmd_ctx->llm->pid = cmd_ctx->lsm->domain.attr.pid;
+       cmd_ctx->llm->cmd_header_size = cmd_header_len;
+       cmd_ctx->llm->data_size = payload_len;
+       cmd_ctx->lttng_msg_size = total_msg_size;
 
-       cmd_ctx->llm->data_size = size;
-       cmd_ctx->lttng_msg_size = sizeof(struct lttcomm_lttng_msg) + buf_size;
+       /* Copy command header */
+       memcpy(((uint8_t *) cmd_ctx->llm) + cmd_header_offset, cmd_header_buf,
+               cmd_header_len);
 
-       return buf_size;
+       /* Copy payload */
+       memcpy(((uint8_t *) cmd_ctx->llm) + payload_offset, payload_buf,
+               payload_len);
 
-error:
+end:
        return ret;
 }
 
+/*
+ * Version of setup_lttng_msg() without command header.
+ */
+static int setup_lttng_msg_no_cmd_header(struct command_ctx *cmd_ctx,
+       void *payload_buf, size_t payload_len)
+{
+       return setup_lttng_msg(cmd_ctx, payload_buf, payload_len, NULL, 0);
+}
 /*
  * Update the kernel poll set of all channel fd available over all tracing
  * session. Add the wakeup pipe at the end of the set.
@@ -3060,7 +3079,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
                break;
        default:
                /* Setup lttng message with no payload */
-               ret = setup_lttng_msg(cmd_ctx, 0);
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, NULL, 0);
                if (ret < 0) {
                        /* This label does not try to unlock the session */
                        goto init_setup_error;
@@ -3602,18 +3621,14 @@ error_add_context:
                 * Setup lttng message with payload size set to the event list size in
                 * bytes and then copy list into the llm payload.
                 */
-               ret = setup_lttng_msg(cmd_ctx, sizeof(struct lttng_event) * nb_events);
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, events,
+                       sizeof(struct lttng_event) * nb_events);
+               free(events);
+
                if (ret < 0) {
-                       free(events);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, events,
-                               sizeof(struct lttng_event) * nb_events);
-
-               free(events);
-
                ret = LTTNG_OK;
                break;
        }
@@ -3636,19 +3651,14 @@ error_add_context:
                 * Setup lttng message with payload size set to the event list size in
                 * bytes and then copy list into the llm payload.
                 */
-               ret = setup_lttng_msg(cmd_ctx,
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, fields,
                                sizeof(struct lttng_event_field) * nb_fields);
+               free(fields);
+
                if (ret < 0) {
-                       free(fields);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, fields,
-                               sizeof(struct lttng_event_field) * nb_fields);
-
-               free(fields);
-
                ret = LTTNG_OK;
                break;
        }
@@ -3668,18 +3678,14 @@ error_add_context:
                 * Setup lttng message with payload size set to the event list size in
                 * bytes and then copy list into the llm payload.
                 */
-               ret = setup_lttng_msg(cmd_ctx, sizeof(struct lttng_event) * nb_events);
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, events,
+                       sizeof(struct lttng_event) * nb_events);
+               free(events);
+
                if (ret < 0) {
-                       free(events);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, events,
-                               sizeof(struct lttng_event) * nb_events);
-
-               free(events);
-
                ret = LTTNG_OK;
                break;
        }
@@ -3700,18 +3706,14 @@ error_add_context:
                 * Setup lttng message with payload size set to the event list size in
                 * bytes and then copy list into the llm payload.
                 */
-               ret = setup_lttng_msg(cmd_ctx, sizeof(int32_t) * nr_pids);
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, pids,
+                       sizeof(int32_t) * nr_pids);
+               free(pids);
+
                if (ret < 0) {
-                       free(pids);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, pids,
-                               sizeof(int) * nr_pids);
-
-               free(pids);
-
                ret = LTTNG_OK;
                break;
        }
@@ -3825,18 +3827,14 @@ error_add_context:
                        goto error;
                }
 
-               ret = setup_lttng_msg(cmd_ctx, nb_dom * sizeof(struct lttng_domain));
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, domains,
+                       nb_dom * sizeof(struct lttng_domain));
+               free(domains);
+
                if (ret < 0) {
-                       free(domains);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, domains,
-                               nb_dom * sizeof(struct lttng_domain));
-
-               free(domains);
-
                ret = LTTNG_OK;
                break;
        }
@@ -3853,18 +3851,14 @@ error_add_context:
                        goto error;
                }
 
-               ret = setup_lttng_msg(cmd_ctx, nb_chan * sizeof(struct lttng_channel));
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, channels,
+                       nb_chan * sizeof(struct lttng_channel));
+               free(channels);
+
                if (ret < 0) {
-                       free(channels);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, channels,
-                               nb_chan * sizeof(struct lttng_channel));
-
-               free(channels);
-
                ret = LTTNG_OK;
                break;
        }
@@ -3881,43 +3875,49 @@ error_add_context:
                        goto error;
                }
 
-               ret = setup_lttng_msg(cmd_ctx, nb_event * sizeof(struct lttng_event));
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, events,
+                       nb_event * sizeof(struct lttng_event));
+               free(events);
+
                if (ret < 0) {
-                       free(events);
                        goto setup_error;
                }
 
-               /* Copy event list into message payload */
-               memcpy(cmd_ctx->llm->payload, events,
-                               nb_event * sizeof(struct lttng_event));
-
-               free(events);
-
                ret = LTTNG_OK;
                break;
        }
        case LTTNG_LIST_SESSIONS:
        {
                unsigned int nr_sessions;
+               void *sessions_payload;
+               size_t payload_len;
 
                session_lock_list();
                nr_sessions = lttng_sessions_count(
                                LTTNG_SOCK_GET_UID_CRED(&cmd_ctx->creds),
                                LTTNG_SOCK_GET_GID_CRED(&cmd_ctx->creds));
+               payload_len = sizeof(struct lttng_session) * nr_sessions;
+               sessions_payload = zmalloc(payload_len);
 
-               ret = setup_lttng_msg(cmd_ctx, sizeof(struct lttng_session) * nr_sessions);
-               if (ret < 0) {
+               if (!sessions_payload) {
                        session_unlock_list();
+                       ret = -ENOMEM;
                        goto setup_error;
                }
 
-               /* Filled the session array */
-               cmd_list_lttng_sessions((struct lttng_session *)(cmd_ctx->llm->payload),
+               cmd_list_lttng_sessions(sessions_payload,
                        LTTNG_SOCK_GET_UID_CRED(&cmd_ctx->creds),
                        LTTNG_SOCK_GET_GID_CRED(&cmd_ctx->creds));
-
                session_unlock_list();
 
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, sessions_payload,
+                       payload_len);
+               free(sessions_payload);
+
+               if (ret < 0) {
+                       goto setup_error;
+               }
+
                ret = LTTNG_OK;
                break;
        }
@@ -3947,14 +3947,10 @@ error_add_context:
        case LTTNG_DATA_PENDING:
        {
                int pending_ret;
-
-               /* 1 byte to return whether or not data is pending */
-               ret = setup_lttng_msg(cmd_ctx, 1);
-               if (ret < 0) {
-                       goto setup_error;
-               }
+               uint8_t pending_ret_byte;
 
                pending_ret = cmd_data_pending(cmd_ctx->session);
+
                /*
                 * FIXME
                 *
@@ -3965,7 +3961,10 @@ error_add_context:
                 * "unknown" error.
                 */
                if (pending_ret == 0 || pending_ret == 1) {
-                       ret = LTTNG_OK;
+                       /*
+                        * ret will be set to LTTNG_OK at the end of
+                        * this function.
+                        */
                } else if (pending_ret < 0) {
                        ret = LTTNG_ERR_UNK;
                        goto setup_error;
@@ -3974,7 +3973,17 @@ error_add_context:
                        goto setup_error;
                }
 
-               *cmd_ctx->llm->payload = (uint8_t) pending_ret;
+               pending_ret_byte = (uint8_t) pending_ret;
+
+               /* 1 byte to return whether or not data is pending */
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx,
+                       &pending_ret_byte, 1);
+
+               if (ret < 0) {
+                       goto setup_error;
+               }
+
+               ret = LTTNG_OK;
                break;
        }
        case LTTNG_SNAPSHOT_ADD_OUTPUT:
@@ -3987,13 +3996,13 @@ error_add_context:
                        goto error;
                }
 
-               ret = setup_lttng_msg(cmd_ctx, sizeof(reply));
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, &reply,
+                       sizeof(reply));
                if (ret < 0) {
                        goto setup_error;
                }
 
                /* Copy output list into message payload */
-               memcpy(cmd_ctx->llm->payload, &reply, sizeof(reply));
                ret = LTTNG_OK;
                break;
        }
@@ -4014,20 +4023,15 @@ error_add_context:
                        goto error;
                }
 
-               ret = setup_lttng_msg(cmd_ctx,
+               assert((nb_output > 0 && outputs) || nb_output == 0);
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, outputs,
                                nb_output * sizeof(struct lttng_snapshot_output));
+               free(outputs);
+
                if (ret < 0) {
-                       free(outputs);
                        goto setup_error;
                }
 
-               if (outputs) {
-                       /* Copy output list into message payload */
-                       memcpy(cmd_ctx->llm->payload, outputs,
-                                       nb_output * sizeof(struct lttng_snapshot_output));
-                       free(outputs);
-               }
-
                ret = LTTNG_OK;
                break;
        }
@@ -4136,7 +4140,7 @@ error_add_context:
 error:
        if (cmd_ctx->llm == NULL) {
                DBG("Missing llm structure. Allocating one.");
-               if (setup_lttng_msg(cmd_ctx, 0) < 0) {
+               if (setup_lttng_msg_no_cmd_header(cmd_ctx, NULL, 0) < 0) {
                        goto setup_error;
                }
        }
index 0d9f4a699479568db957669a2e9814d50a56e323..675e54c2d6adffba777234885cc89ccf106d3cfb 100644 (file)
@@ -350,8 +350,6 @@ struct lttcomm_lttng_msg {
        uint32_t pid;           /* pid_t */
        uint32_t cmd_header_size;
        uint32_t data_size;
-       /* Contains: trace_name + data */
-       char payload[];
 } LTTNG_PACKED;
 
 struct lttcomm_lttng_output_id {
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