Fix: Consumer return value check after mmap/splice
[lttng-tools.git] / src / common / ust-consumer / ust-consumer.c
index 5f5e9582574011577297bf36123a64958a752793..8ab2b819dcee52a237518b1ce6f8cba5f3e1aa1f 100644 (file)
@@ -2,36 +2,38 @@
  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; only version 2
- * of the License.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2 only,
+ * as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #define _GNU_SOURCE
 #include <assert.h>
-#include <fcntl.h>
+#include <lttng/ust-ctl.h>
 #include <poll.h>
 #include <pthread.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/mman.h>
 #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>
+#include <common/relayd/relayd.h>
+#include <common/compat/fcntl.h>
 
 #include "ust-consumer.h"
 
@@ -40,61 +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
+ * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
+ * compiled out, we isolate it in this library.
  */
-int lttng_ustconsumer_on_read_subbuffer_mmap(
-               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)
 {
-       unsigned long mmap_offset;
-       long ret = 0;
-       off_t orig_offset = stream->out_fd_offset;
-       int outfd = stream->out_fd;
-
-       /* get the offset inside the fd to mmap */
-       ret = ustctl_get_mmap_read_offset(stream->chan->handle,
-               stream->buf, &mmap_offset);
-       if (ret != 0) {
-               ret = -errno;
-               perror("ustctl_get_mmap_read_offset");
-               goto end;
-       }
-       while (len > 0) {
-               ret = write(outfd, stream->mmap_base + mmap_offset, len);
-               if (ret >= len) {
-                       len = 0;
-               } else if (ret < 0) {
-                       ret = -errno;
-                       perror("Error in file write");
-                       goto end;
-               }
-               /* This won't block, but will start writeout asynchronously */
-               sync_file_range(outfd, stream->out_fd_offset, ret,
-                               SYNC_FILE_RANGE_WRITE);
-               stream->out_fd_offset += ret;
-       }
-
-       lttng_consumer_sync_trace_file(stream, orig_offset);
-
-       goto end;
-
-end:
-       return ret;
-}
-
-/*
- * Splice the data from the ring buffer to the tracefile.
- *
- * Returns the number of bytes spliced.
- */
-int lttng_ustconsumer_on_read_subbuffer_splice(
-               struct lttng_consumer_local_data *ctx,
-               struct lttng_consumer_stream *stream, unsigned long len)
-{
-       return -ENOSYS;
-}
+       return ustctl_get_mmap_read_offset(handle, buf, off);
+};
 
 /*
  * Take a snapshot for a specific fd
@@ -108,8 +63,8 @@ int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
 
        ret = ustctl_snapshot(stream->chan->handle, stream->buf);
        if (ret != 0) {
-               ret = errno;
-               perror("Getting sub-buffer snapshot.");
+               errno = -ret;
+               PERROR("Getting sub-buffer snapshot.");
        }
 
        return ret;
@@ -130,13 +85,18 @@ int lttng_ustconsumer_get_produced_snapshot(
        ret = ustctl_snapshot_get_produced(stream->chan->handle,
                        stream->buf, pos);
        if (ret != 0) {
-               ret = errno;
-               perror("kernctl_snapshot_get_produced");
+               errno = -ret;
+               PERROR("kernctl_snapshot_get_produced");
        }
 
        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)
 {
@@ -145,27 +105,43 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 
        ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
        if (ret != sizeof(msg)) {
-               lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
+               DBG("Consumer received unexpected message size %zd (expects %zu)",
+                       ret, sizeof(msg));
+               lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
                return ret;
        }
        if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
                return -ENOENT;
        }
 
+       /* relayd needs RCU read-side lock */
+       rcu_read_lock();
+
        switch (msg.cmd_type) {
+       case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
+       {
+               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:
        {
                struct lttng_consumer_channel *new_channel;
                int fds[1];
                size_t nb_fd = 1;
 
+               DBG("UST Consumer adding channel");
+
                /* 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;
                }
 
@@ -176,7 +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) {
@@ -196,21 +172,28 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                struct lttng_consumer_stream *new_stream;
                int fds[2];
                size_t nb_fd = 2;
+               struct consumer_relayd_sock_pair *relayd = NULL;
+
+               DBG("UST Consumer adding stream");
 
                /* 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;
                }
 
-               DBG("consumer_add_stream %s (%d,%d)", msg.u.stream.path_name,
-                       fds[0], fds[1]);
+               DBG("consumer_add_stream chan %d stream %d",
+                               msg.u.stream.channel_key,
+                               msg.u.stream.stream_key);
+
                assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
-               new_stream = consumer_allocate_stream(msg.u.channel.channel_key,
+               new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
                                msg.u.stream.stream_key,
                                fds[0], fds[1],
                                msg.u.stream.state,
@@ -218,25 +201,95 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                msg.u.stream.output,
                                msg.u.stream.path_name,
                                msg.u.stream.uid,
-                               msg.u.stream.gid);
+                               msg.u.stream.gid,
+                               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;
                }
-               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;
+
+               /* The stream is not metadata. Get relayd reference if exists. */
+               relayd = consumer_find_relayd(msg.u.stream.net_index);
+               if (relayd != NULL) {
+                       pthread_mutex_lock(&relayd->ctrl_sock_mutex);
+                       /* Add stream on the relayd */
+                       ret = relayd_add_stream(&relayd->control_sock,
+                                       msg.u.stream.name, msg.u.stream.path_name,
+                                       &new_stream->relayd_stream_id);
+                       pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
+                       if (ret < 0) {
+                               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_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);
                }
+
+               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 %" PRIu64, index);
+
+               /* Get relayd reference if exists. */
+               relayd = consumer_find_relayd(index);
+               if (relayd == NULL) {
+                       ERR("Unable to find relayd %" PRIu64, index);
+                       goto end_nosignal;
+               }
+
+               /*
+                * 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);
+
+               goto end_nosignal;
+       }
        case LTTNG_CONSUMER_UPDATE_STREAM:
        {
+               rcu_read_unlock();
                return -ENOSYS;
 #if 0
                if (ctx->on_update_stream != NULL) {
@@ -250,20 +303,35 @@ 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:
-       /* signal the poll thread */
-       ret = write(ctx->consumer_poll_pipe[1], "4", 1);
-       if (ret < 0) {
-               perror("write consumer poll");
-       }
+
+       /*
+        * 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).
+        */
+       do {
+               ret = write(ctx->consumer_poll_pipe[1], "", 1);
+       } while (ret < 0 && errno == EINTR);
 end_nosignal:
-       return 0;
+       rcu_read_unlock();
+
+       /*
+        * 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)
@@ -331,7 +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;
@@ -346,7 +414,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
        if (!stream->hangup_flush_done) {
                do {
                        readlen = read(stream->wait_fd, &dummy, 1);
-               } while (readlen == -1 && errno == -EINTR);
+               } while (readlen == -1 && errno == EINTR);
                if (readlen == -1) {
                        ret = readlen;
                        goto end;
@@ -358,7 +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,
@@ -370,17 +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 < 0) {
+       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");
+               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);
@@ -393,14 +478,14 @@ int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
        int ret;
 
        /* Opening the tracefile in write mode */
-       if (stream->path_name != NULL) {
+       if (stream->path_name != NULL && stream->net_seq_idx == -1) {
                ret = run_as_open(stream->path_name,
                                O_WRONLY|O_CREAT|O_TRUNC,
                                S_IRWXU|S_IRWXG|S_IRWXO,
                                stream->uid, stream->gid);
                if (ret < 0) {
                        ERR("Opening %s", stream->path_name);
-                       perror("open");
+                       PERROR("open");
                        goto error;
                }
                stream->out_fd = ret;
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