Fix: Consumer return value check after mmap/splice
[lttng-tools.git] / src / common / ust-consumer / ust-consumer.c
index 3024af4a75157b92a46a67014800b9eab66c8e64..8ab2b819dcee52a237518b1ce6f8cba5f3e1aa1f 100644 (file)
@@ -92,6 +92,11 @@ int lttng_ustconsumer_get_produced_snapshot(
        return ret;
 }
 
+/*
+ * Receive command from session daemon and process it.
+ *
+ * Return 1 on success else a negative value or 0.
+ */
 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                int sock, struct pollfd *consumer_sockpoll)
 {
@@ -102,7 +107,7 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        if (ret != sizeof(msg)) {
                DBG("Consumer received unexpected message size %zd (expects %zu)",
                        ret, sizeof(msg));
-               lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
+               lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
                return ret;
        }
        if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
@@ -115,81 +120,9 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        switch (msg.cmd_type) {
        case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
        {
-               int fd;
-               struct consumer_relayd_sock_pair *relayd;
-
-               DBG("UST Consumer adding relayd socket");
-
-               /* Get relayd reference if exists. */
-               relayd = consumer_find_relayd(msg.u.relayd_sock.net_index);
-               if (relayd == NULL) {
-                       /* Not found. Allocate one. */
-                       relayd = consumer_allocate_relayd_sock_pair(
-                                       msg.u.relayd_sock.net_index);
-                       if (relayd == NULL) {
-                               lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
-                               goto end_nosignal;
-                       }
-               }
-
-               /* Poll on consumer socket. */
-               if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
-                       rcu_read_unlock();
-                       return -EINTR;
-               }
-
-               /* Get relayd socket from session daemon */
-               ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
-               if (ret != sizeof(fd)) {
-                       lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
-                       goto end_nosignal;
-               }
-
-               /* Copy socket information and received FD */
-               switch (msg.u.relayd_sock.type) {
-               case LTTNG_STREAM_CONTROL:
-                       /* Copy received lttcomm socket */
-                       lttcomm_copy_sock(&relayd->control_sock, &msg.u.relayd_sock.sock);
-                       ret = lttcomm_create_sock(&relayd->control_sock);
-                       if (ret < 0) {
-                               goto end_nosignal;
-                       }
-
-                       /* Close the created socket fd which is useless */
-                       close(relayd->control_sock.fd);
-
-                       /* Assign new file descriptor */
-                       relayd->control_sock.fd = fd;
-                       break;
-               case LTTNG_STREAM_DATA:
-                       /* Copy received lttcomm socket */
-                       lttcomm_copy_sock(&relayd->data_sock, &msg.u.relayd_sock.sock);
-                       ret = lttcomm_create_sock(&relayd->data_sock);
-                       if (ret < 0) {
-                               goto end_nosignal;
-                       }
-
-                       /* Close the created socket fd which is useless */
-                       close(relayd->data_sock.fd);
-
-                       /* Assign new file descriptor */
-                       relayd->data_sock.fd = fd;
-                       break;
-               default:
-                       ERR("Unknown relayd socket type");
-                       goto end_nosignal;
-               }
-
-               DBG("Consumer %s socket created successfully with net idx %d (fd: %d)",
-                               msg.u.relayd_sock.type == LTTNG_STREAM_CONTROL ? "control" : "data",
-                               relayd->net_seq_idx, fd);
-
-               /*
-                * Add relayd socket pair to consumer data hashtable. If object already
-                * exists or on error, the function gracefully returns.
-                */
-               consumer_add_relayd(relayd);
-
+               ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
+                               msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
+                               &msg.u.relayd_sock.sock);
                goto end_nosignal;
        }
        case LTTNG_CONSUMER_ADD_CHANNEL:
@@ -207,7 +140,7 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                }
                ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
                if (ret != sizeof(fds)) {
-                       lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
+                       lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
                        rcu_read_unlock();
                        return ret;
                }
@@ -219,7 +152,7 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                msg.u.channel.mmap_len,
                                msg.u.channel.max_sb_size);
                if (new_channel == NULL) {
-                       lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
+                       lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
                        goto end_nosignal;
                }
                if (ctx->on_recv_channel != NULL) {
@@ -250,7 +183,7 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                }
                ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
                if (ret != sizeof(fds)) {
-                       lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
+                       lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
                        rcu_read_unlock();
                        return ret;
                }
@@ -272,7 +205,7 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                msg.u.stream.net_index,
                                msg.u.stream.metadata_flag);
                if (new_stream == NULL) {
-                       lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
+                       lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
                        goto end_nosignal;
                }
 
@@ -295,14 +228,29 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        goto end_nosignal;
                }
 
-               if (ctx->on_recv_stream != NULL) {
-                       ret = ctx->on_recv_stream(new_stream);
-                       if (ret == 0) {
-                               consumer_add_stream(new_stream);
-                       } else if (ret < 0) {
-                               goto end_nosignal;
+               /* Send stream to the metadata thread */
+               if (new_stream->metadata_flag) {
+                       if (ctx->on_recv_stream) {
+                               ret = ctx->on_recv_stream(new_stream);
+                               if (ret < 0) {
+                                       goto end_nosignal;
+                               }
+                       }
+
+                       do {
+                               ret = write(ctx->consumer_metadata_pipe[1], new_stream,
+                                               sizeof(struct lttng_consumer_stream));
+                       } while (ret < 0 && errno == EINTR);
+                       if (ret < 0) {
+                               PERROR("write metadata pipe");
                        }
                } else {
+                       if (ctx->on_recv_stream) {
+                               ret = ctx->on_recv_stream(new_stream);
+                               if (ret < 0) {
+                                       goto end_nosignal;
+                               }
+                       }
                        consumer_add_stream(new_stream);
                }
 
@@ -313,25 +261,30 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        }
        case LTTNG_CONSUMER_DESTROY_RELAYD:
        {
+               uint64_t index = msg.u.destroy_relayd.net_seq_idx;
                struct consumer_relayd_sock_pair *relayd;
 
-               DBG("UST consumer destroying relayd %" PRIu64,
-                               msg.u.destroy_relayd.net_seq_idx);
+               DBG("UST consumer destroying relayd %" PRIu64, index);
 
                /* Get relayd reference if exists. */
-               relayd = consumer_find_relayd(msg.u.destroy_relayd.net_seq_idx);
+               relayd = consumer_find_relayd(index);
                if (relayd == NULL) {
-                       ERR("Unable to find relayd %" PRIu64, msg.u.destroy_relayd.net_seq_idx);
+                       ERR("Unable to find relayd %" PRIu64, index);
                        goto end_nosignal;
                }
 
-               /* Set destroy flag for this object */
-               uatomic_set(&relayd->destroy_flag, 1);
+               /*
+                * Each relayd socket pair has a refcount of stream attached to it
+                * which tells if the relayd is still active or not depending on the
+                * refcount value.
+                *
+                * This will set the destroy flag of the relayd object and destroy it
+                * if the refcount reaches zero when called.
+                *
+                * The destroy can happen either here or when a stream fd hangs up.
+                */
+               consumer_flag_relayd_for_destroy(relayd);
 
-               /* Destroy the relayd if refcount is 0 else set the destroy flag. */
-               if (uatomic_read(&relayd->refcount) == 0) {
-                       consumer_destroy_relayd(relayd);
-               }
                goto end_nosignal;
        }
        case LTTNG_CONSUMER_UPDATE_STREAM:
@@ -373,7 +326,12 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        } while (ret < 0 && errno == EINTR);
 end_nosignal:
        rcu_read_unlock();
-       return 0;
+
+       /*
+        * Return 1 to indicate success since the 0 value can be a socket
+        * shutdown during the recv() or send() call.
+        */
+       return 1;
 }
 
 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
@@ -441,7 +399,7 @@ void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                struct lttng_consumer_local_data *ctx)
 {
-       unsigned long len;
+       unsigned long len, subbuf_size, padding;
        int err;
        long ret = 0;
        struct lttng_ust_shm_handle *handle;
@@ -468,7 +426,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
        /* Get the next subbuffer */
        err = ustctl_get_next_subbuf(handle, buf);
        if (err != 0) {
-               ret = -ret;     /* ustctl_get_next_subbuf returns negative, caller expect positive. */
+               ret = err;      /* ustctl_get_next_subbuf returns negative, caller expect positive. */
                /*
                 * This is a debug message even for single-threaded consumer,
                 * because poll() have more relaxed criterions than get subbuf,
@@ -480,17 +438,34 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                goto end;
        }
        assert(stream->output == LTTNG_EVENT_MMAP);
-       /* read the used subbuffer size */
+       /* Get the full padded subbuffer size */
        err = ustctl_get_padded_subbuf_size(handle, buf, &len);
        assert(err == 0);
+
+       /* Get subbuffer data size (without padding) */
+       err = ustctl_get_subbuf_size(handle, buf, &subbuf_size);
+       assert(err == 0);
+
+       /* Make sure we don't get a subbuffer size bigger than the padded */
+       assert(len >= subbuf_size);
+
+       padding = len - subbuf_size;
        /* write the subbuffer to the tracefile */
-       ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
-       if (ret != len) {
+       ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding);
+       /*
+        * The mmap operation should write subbuf_size amount of data when network
+        * streaming or the full padding (len) size when we are _not_ streaming.
+        */
+       if ((ret != subbuf_size && stream->net_seq_idx != -1) ||
+                       (ret != len && stream->net_seq_idx == -1)) {
                /*
-                * display the error but continue processing to try
-                * to release the subbuffer
+                * Display the error but continue processing to try to release the
+                * subbuffer
                 */
-               ERR("Error writing to tracefile (expected: %ld, got: %ld)", ret, len);
+               ERR("Error writing to tracefile "
+                               "(ret: %zd != len: %lu != subbuf_size: %lu)",
+                               ret, len, subbuf_size);
+
        }
        err = ustctl_put_next_subbuf(handle, buf);
        assert(err == 0);
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