Fix: consumer recv command error path
[lttng-tools.git] / src / common / ust-consumer / ust-consumer.c
index 07a68d8f755da7813d765357b5a2379f86b0b589..2b8098835857106a811f03761fcafe7489f1ce1f 100644 (file)
@@ -18,6 +18,7 @@
 
 #define _GNU_SOURCE
 #include <assert.h>
+#include <lttng/ust-ctl.h>
 #include <poll.h>
 #include <pthread.h>
 #include <stdlib.h>
@@ -26,8 +27,8 @@
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <inttypes.h>
 #include <unistd.h>
-#include <lttng/ust-ctl.h>
 
 #include <common/common.h>
 #include <common/sessiond-comm/sessiond-comm.h>
@@ -41,127 +42,14 @@ extern int consumer_poll_timeout;
 extern volatile int consumer_quit;
 
 /*
- * Mmap the ring buffer, read it and write the data to the tracefile.
- *
- * Returns the number of bytes written, else negative value on error.
- */
-ssize_t lttng_ustconsumer_on_read_subbuffer_mmap(
-               struct lttng_consumer_local_data *ctx,
-               struct lttng_consumer_stream *stream, unsigned long len)
-{
-       unsigned long mmap_offset;
-       long ret = 0, written = 0;
-       off_t orig_offset = stream->out_fd_offset;
-       int outfd = stream->out_fd;
-       uint64_t metadata_id;
-       struct consumer_relayd_sock_pair *relayd = NULL;
-
-       /* RCU lock for the relayd pointer */
-       rcu_read_lock();
-
-       /* Flag that the current stream if set for network streaming. */
-       if (stream->net_seq_idx != -1) {
-               relayd = consumer_find_relayd(stream->net_seq_idx);
-               if (relayd == NULL) {
-                       ERR("UST consumer mmap(), unable to find relay for index %d",
-                                       stream->net_seq_idx);
-                       goto end;
-               }
-       }
-
-       /* get the offset inside the fd to mmap */
-       ret = ustctl_get_mmap_read_offset(stream->chan->handle,
-               stream->buf, &mmap_offset);
-       if (ret != 0) {
-               errno = -ret;
-               PERROR("ustctl_get_mmap_read_offset");
-               written = ret;
-               goto end;
-       }
-
-       /* Handle stream on the relayd if the output is on the network */
-       if (relayd) {
-               unsigned long netlen = len;
-
-               if (stream->metadata_flag) {
-                       /* Only lock if metadata since we use the control socket. */
-                       pthread_mutex_lock(&relayd->ctrl_sock_mutex);
-                       netlen += sizeof(stream->relayd_stream_id);
-               }
-
-               ret = consumer_handle_stream_before_relayd(stream, netlen);
-               if (ret >= 0) {
-                       outfd = ret;
-
-                       /* Write metadata stream id before payload */
-                       if (stream->metadata_flag) {
-                               metadata_id = htobe64(stream->relayd_stream_id);
-                               do {
-                                       ret = write(outfd, (void *) &metadata_id,
-                                                       sizeof(stream->relayd_stream_id));
-                               } while (ret < 0 && errno == EINTR);
-                               if (ret < 0) {
-                                       PERROR("write metadata stream id");
-                                       written = ret;
-                                       goto end;
-                               }
-                               DBG("Metadata stream id %zu written before data",
-                                               stream->relayd_stream_id);
-                       }
-               }
-               /* Else, use the default set before which is the filesystem. */
-       }
-
-       while (len > 0) {
-               do {
-                       ret = write(outfd, stream->mmap_base + mmap_offset, len);
-               } while (ret < 0 && errno == EINTR);
-               if (ret < 0) {
-                       PERROR("Error in file write");
-                       if (written == 0) {
-                               written = ret;
-                       }
-                       goto end;
-               } else if (ret > len) {
-                       PERROR("ret %ld > len %lu", ret, len);
-                       written += ret;
-                       goto end;
-               } else {
-                       len -= ret;
-                       mmap_offset += ret;
-               }
-               DBG("UST mmap write() ret %ld (len %lu)", ret, len);
-
-               /* This call is useless on a socket so better save a syscall. */
-               if (!relayd) {
-                       /* This won't block, but will start writeout asynchronously */
-                       lttng_sync_file_range(outfd, stream->out_fd_offset, ret,
-                                       SYNC_FILE_RANGE_WRITE);
-                       stream->out_fd_offset += ret;
-               }
-               written += ret;
-       }
-       lttng_consumer_sync_trace_file(stream, orig_offset);
-
-end:
-       if (relayd && stream->metadata_flag) {
-               pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
-       }
-       rcu_read_unlock();
-       return written;
-}
-
-/*
- * Splice the data from the ring buffer to the tracefile.
- *
- * Returns the number of bytes spliced.
+ * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
+ * compiled out, we isolate it in this library.
  */
-ssize_t lttng_ustconsumer_on_read_subbuffer_splice(
-               struct lttng_consumer_local_data *ctx,
-               struct lttng_consumer_stream *stream, unsigned long len)
+int lttng_ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
+               struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
 {
-       return -ENOSYS;
-}
+       return ustctl_get_mmap_read_offset(handle, buf, off);
+};
 
 /*
  * Take a snapshot for a specific fd
@@ -204,6 +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)
 {
@@ -214,93 +107,22 @@ 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) {
                return -ENOENT;
        }
 
-       /* relayd need RCU read-side lock */
+       /* relayd needs RCU read-side lock */
        rcu_read_lock();
 
        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) {
-                       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:
@@ -313,11 +135,13 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 
                /* block */
                if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
+                       rcu_read_unlock();
                        return -EINTR;
                }
                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;
                }
 
@@ -328,7 +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) {
@@ -354,11 +178,13 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 
                /* block */
                if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
+                       rcu_read_unlock();
                        return -EINTR;
                }
                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;
                }
 
@@ -379,8 +205,8 @@ 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);
-                       goto end;
+                       lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
+                       goto end_nosignal;
                }
 
                /* The stream is not metadata. Get relayd reference if exists. */
@@ -393,13 +219,13 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                        &new_stream->relayd_stream_id);
                        pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
                        if (ret < 0) {
-                               goto end;
+                               goto end_nosignal;
                        }
                } else if (msg.u.stream.net_index != -1) {
                        ERR("Network sequence index %d unknown. Not adding stream.",
                                        msg.u.stream.net_index);
                        free(new_stream);
-                       goto end;
+                       goto end_nosignal;
                }
 
                if (ctx->on_recv_stream != NULL) {
@@ -407,42 +233,48 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        if (ret == 0) {
                                consumer_add_stream(new_stream);
                        } else if (ret < 0) {
-                               goto end;
+                               goto end_nosignal;
                        }
                } else {
                        consumer_add_stream(new_stream);
                }
 
-               DBG("UST consumer_add_stream %s (%d,%d) with relayd id %lu",
+               DBG("UST consumer_add_stream %s (%d,%d) with relayd id %" PRIu64,
                                msg.u.stream.path_name, fds[0], fds[1],
                                new_stream->relayd_stream_id);
                break;
        }
        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 %zu",
-                               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 %zu",
-                                       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);
-               }
-               break;
+               goto end_nosignal;
        }
        case LTTNG_CONSUMER_UPDATE_STREAM:
        {
+               rcu_read_unlock();
                return -ENOSYS;
 #if 0
                if (ctx->on_update_stream != NULL) {
@@ -456,20 +288,20 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        consumer_change_stream_state(msg.u.stream.stream_key,
                                msg.u.stream.state);
                }
-#endif
                break;
+#endif
        }
        default:
                break;
        }
-end:
+
        /*
-        * Wake-up the other end by writing a null byte in the pipe
-        * (non-blocking). Important note: Because writing into the
-        * pipe is non-blocking (and therefore we allow dropping wakeup
-        * data, as long as there is wakeup data present in the pipe
-        * buffer to wake up the other end), the other end should
-        * perform the following sequence for waiting:
+        * Wake-up the other end by writing a null byte in the pipe (non-blocking).
+        * Important note: Because writing into the pipe is non-blocking (and
+        * therefore we allow dropping wakeup data, as long as there is wakeup data
+        * present in the pipe buffer to wake up the other end), the other end
+        * should perform the following sequence for waiting:
+        *
         * 1) empty the pipe (reads).
         * 2) perform update operation.
         * 3) wait on the pipe (poll).
@@ -479,7 +311,12 @@ end:
        } 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)
@@ -596,7 +433,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                 * display the error but continue processing to try
                 * to release the subbuffer
                 */
-               ERR("Error writing to tracefile");
+               ERR("Error writing to tracefile (expected: %ld, got: %ld)", ret, len);
        }
        err = ustctl_put_next_subbuf(handle, buf);
        assert(err == 0);
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