Merged! Thanks

FIN
David

On 11-08-12 10:14 AM, Mathieu Desnoyers wrote:
> * Julien Desfossez ([email protected]) wrote:
>> The init function of the library now takes a function as argument to
>> allow a consumer using the library to control the function to be called
>> when data is ready in a buffer.
>> The kconsumerd_on_read_subbuffer_mmap and
>> kconsumerd_on_read_subbuffer_splice are now exported to allow a consumer
>> to use them directly if needed.
>> Also the library has now a context, where all local parameters are
>> registered instead of static variables. That way, we can have multiple
>> callers using the library within the same process.
>> Only the flag indicating that all fds are closed remain global to the
>> library and shared among callers.
> 
> Acked-by: Mathieu Desnoyers <[email protected]>
> 
> Thanks!
> 
> Mathieu
> 
>>
>> Signed-off-by: Julien Desfossez <[email protected]>
>> ---
>>  liblttkconsumerd/lttkconsumerd.c |  281 
>> +++++++++++++++-----------------------
>>  liblttkconsumerd/lttkconsumerd.h |   61 +++++++-
>>  ltt-kconsumerd/ltt-kconsumerd.c  |  110 +++++++++++++--
>>  3 files changed, 263 insertions(+), 189 deletions(-)
>>
>> diff --git a/liblttkconsumerd/lttkconsumerd.c 
>> b/liblttkconsumerd/lttkconsumerd.c
>> index 5c22d5e..d4908d1 100644
>> --- a/liblttkconsumerd/lttkconsumerd.c
>> +++ b/liblttkconsumerd/lttkconsumerd.c
>> @@ -62,26 +62,13 @@ struct kconsumerd_global_data {
>>      unsigned int need_update;
>>  } kconsumerd_data = {
>>      .fd_list.head = CDS_LIST_HEAD_INIT(kconsumerd_data.fd_list.head),
>> +    .fds_count = 0,
>> +    .need_update = 1,
>>  };
>>  
>> -/* communication with splice */
>> -static int kconsumerd_thread_pipe[2];
>> -
>> -/* pipe to wake the poll thread when necessary */
>> -static int kconsumerd_poll_pipe[2];
>> -
>> -/* to let the signal handler wake up the fd receiver thread */
>> -static int kconsumerd_should_quit[2];
>> -
>>  /* timeout parameter, to control the polling thread grace period */
>>  static int kconsumerd_poll_timeout = -1;
>>  
>> -/* socket to communicate errors with sessiond */
>> -static int kconsumerd_error_socket;
>> -
>> -/* socket to exchange commands with sessiond */
>> -static char *kconsumerd_command_sock_path;
>> -
>>  /*
>>   * flag to inform the polling thread to quit when all fd hung up.
>>   * Updated by the kconsumerd_thread_receive_fds when it notices that all
>> @@ -95,9 +82,9 @@ static volatile int kconsumerd_quit = 0;
>>   *
>>   * Set the error socket
>>   */
>> -void kconsumerd_set_error_socket(int sock)
>> +void kconsumerd_set_error_socket(struct kconsumerd_local_data *ctx, int 
>> sock)
>>  {
>> -    kconsumerd_error_socket = sock;
>> +    ctx->kconsumerd_error_socket = sock;
>>  }
>>  
>>  /*
>> @@ -105,9 +92,10 @@ void kconsumerd_set_error_socket(int sock)
>>   *
>>   * Set the command socket path
>>   */
>> -void kconsumerd_set_command_socket_path(char *sock)
>> +void kconsumerd_set_command_socket_path(struct kconsumerd_local_data *ctx,
>> +            char *sock)
>>  {
>> -    kconsumerd_command_sock_path = sock;
>> +    ctx->kconsumerd_command_sock_path = sock;
>>  }
>>  
>>  /*
>> @@ -144,7 +132,9 @@ static void kconsumerd_del_fd(struct kconsumerd_fd *lcf)
>>      if (kconsumerd_data.fds_count > 0) {
>>              kconsumerd_data.fds_count--;
>>              if (lcf != NULL) {
>> -                    close(lcf->out_fd);
>> +                    if (lcf->out_fd != 0) {
>> +                            close(lcf->out_fd);
>> +                    }
>>                      close(lcf->consumerd_fd);
>>                      free(lcf);
>>                      lcf = NULL;
>> @@ -161,8 +151,8 @@ static void kconsumerd_del_fd(struct kconsumerd_fd *lcf)
>>   */
>>  static int kconsumerd_add_fd(struct lttcomm_kconsumerd_msg *buf, int 
>> consumerd_fd)
>>  {
>> -    int ret;
>>      struct kconsumerd_fd *tmp_fd;
>> +    int ret = 0;
>>  
>>      pthread_mutex_lock(&kconsumerd_data.lock);
>>      /* Check if already exist */
>> @@ -176,22 +166,24 @@ static int kconsumerd_add_fd(struct 
>> lttcomm_kconsumerd_msg *buf, int consumerd_f
>>      tmp_fd->consumerd_fd = consumerd_fd;
>>      tmp_fd->state = buf->state;
>>      tmp_fd->max_sb_size = buf->max_sb_size;
>> +    tmp_fd->out_fd = 0;
>> +    tmp_fd->out_fd_offset = 0;
>>      strncpy(tmp_fd->path_name, buf->path_name, PATH_MAX);
>>      tmp_fd->path_name[PATH_MAX - 1] = '\0';
>>  
>>      /* Opening the tracefile in write mode */
>> -    ret = open(tmp_fd->path_name,
>> -                    O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU|S_IRWXG|S_IRWXO);
>> -    if (ret < 0) {
>> -            ERR("Opening %s", tmp_fd->path_name);
>> -            perror("open");
>> -            goto end;
>> +    if (tmp_fd->path_name != NULL) {
>> +            ret = open(tmp_fd->path_name,
>> +                            O_WRONLY|O_CREAT|O_TRUNC, 
>> S_IRWXU|S_IRWXG|S_IRWXO);
>> +            if (ret < 0) {
>> +                    ERR("Opening %s", tmp_fd->path_name);
>> +                    perror("open");
>> +                    goto end;
>> +            }
>> +            tmp_fd->out_fd = ret;
>> +            DBG("Adding %s (%d, %d, %d)", tmp_fd->path_name,
>> +                            tmp_fd->sessiond_fd, tmp_fd->consumerd_fd, 
>> tmp_fd->out_fd);
>>      }
>> -    tmp_fd->out_fd = ret;
>> -    tmp_fd->out_fd_offset = 0;
>> -
>> -    DBG("Adding %s (%d, %d, %d)", tmp_fd->path_name,
>> -                    tmp_fd->sessiond_fd, tmp_fd->consumerd_fd, 
>> tmp_fd->out_fd);
>>  
>>      cds_list_add(&tmp_fd->list, &kconsumerd_data.fd_list.head);
>>      kconsumerd_data.fds_count++;
>> @@ -231,16 +223,14 @@ static void kconsumerd_change_fd_state(int sessiond_fd,
>>   * Returns the number of fds in the structures
>>   * Called with kconsumerd_data.lock held.
>>   */
>> -static int kconsumerd_update_poll_array(struct pollfd **pollfd,
>> -            struct kconsumerd_fd **local_kconsumerd_fd)
>> +static int kconsumerd_update_poll_array(struct kconsumerd_local_data *ctx,
>> +            struct pollfd **pollfd, struct kconsumerd_fd 
>> **local_kconsumerd_fd)
>>  {
>>      struct kconsumerd_fd *iter;
>>      int i = 0;
>>  
>>      DBG("Updating poll fd array");
>> -
>>      cds_list_for_each_entry(iter, &kconsumerd_data.fd_list.head, list) {
>> -            DBG("Inside for each");
>>              if (iter->state == ACTIVE_FD) {
>>                      DBG("Active FD %d", iter->consumerd_fd);
>>                      (*pollfd)[i].fd = iter->consumerd_fd;
>> @@ -254,7 +244,7 @@ static int kconsumerd_update_poll_array(struct pollfd 
>> **pollfd,
>>       * insert the kconsumerd_poll_pipe at the end of the array and don't
>>       * increment i so nb_fd is the number of real FD
>>       */
>> -    (*pollfd)[i].fd = kconsumerd_poll_pipe[0];
>> +    (*pollfd)[i].fd = ctx->kconsumerd_poll_pipe[0];
>>      (*pollfd)[i].events = POLLIN;
>>      return i;
>>  }
>> @@ -266,7 +256,7 @@ static int kconsumerd_update_poll_array(struct pollfd 
>> **pollfd,
>>   * mmap the ring buffer, read it and write the data to the tracefile.
>>   * Returns the number of bytes written
>>   */
>> -static int kconsumerd_on_read_subbuffer_mmap(
>> +int kconsumerd_on_read_subbuffer_mmap(struct kconsumerd_local_data *ctx,
>>              struct kconsumerd_fd *kconsumerd_fd, unsigned long len)
>>  {
>>      unsigned long mmap_len, mmap_offset, padded_len, padding_len;
>> @@ -379,7 +369,7 @@ end:
>>   * Splice the data from the ring buffer to the tracefile.
>>   * Returns the number of bytes spliced
>>   */
>> -static int kconsumerd_on_read_subbuffer(
>> +int kconsumerd_on_read_subbuffer_splice(struct kconsumerd_local_data *ctx,
>>              struct kconsumerd_fd *kconsumerd_fd, unsigned long len)
>>  {
>>      long ret = 0;
>> @@ -391,7 +381,7 @@ static int kconsumerd_on_read_subbuffer(
>>      while (len > 0) {
>>              DBG("splice chan to pipe offset %lu (fd : %d)",
>>                              (unsigned long)offset, fd);
>> -            ret = splice(fd, &offset, kconsumerd_thread_pipe[1], NULL, len,
>> +            ret = splice(fd, &offset, ctx->kconsumerd_thread_pipe[1], NULL, 
>> len,
>>                              SPLICE_F_MOVE | SPLICE_F_MORE);
>>              DBG("splice chan to pipe ret %ld", ret);
>>              if (ret < 0) {
>> @@ -400,7 +390,7 @@ static int kconsumerd_on_read_subbuffer(
>>                      goto splice_error;
>>              }
>>  
>> -            ret = splice(kconsumerd_thread_pipe[0], NULL, outfd, NULL, ret,
>> +            ret = splice(ctx->kconsumerd_thread_pipe[0], NULL, outfd, NULL, 
>> ret,
>>                              SPLICE_F_MOVE | SPLICE_F_MORE);
>>              DBG("splice pipe to file %ld", ret);
>>              if (ret < 0) {
>> @@ -452,98 +442,17 @@ splice_error:
>>      /* send the appropriate error description to sessiond */
>>      switch(ret) {
>>      case EBADF:
>> -            kconsumerd_send_error(KCONSUMERD_SPLICE_EBADF);
>> +            kconsumerd_send_error(ctx, KCONSUMERD_SPLICE_EBADF);
>>              break;
>>      case EINVAL:
>> -            kconsumerd_send_error(KCONSUMERD_SPLICE_EINVAL);
>> +            kconsumerd_send_error(ctx, KCONSUMERD_SPLICE_EINVAL);
>>              break;
>>      case ENOMEM:
>> -            kconsumerd_send_error(KCONSUMERD_SPLICE_ENOMEM);
>> +            kconsumerd_send_error(ctx, KCONSUMERD_SPLICE_ENOMEM);
>>              break;
>>      case ESPIPE:
>> -            kconsumerd_send_error(KCONSUMERD_SPLICE_ESPIPE);
>> -            break;
>> -    }
>> -
>> -end:
>> -    return ret;
>> -}
>> -
>> -/*
>> - * kconsumerd_read_subbuffer
>> - *
>> - * Consume data on a file descriptor and write it on a trace file
>> - */
>> -static int kconsumerd_read_subbuffer(struct kconsumerd_fd *kconsumerd_fd)
>> -{
>> -    unsigned long len;
>> -    int err;
>> -    long ret = 0;
>> -    int infd = kconsumerd_fd->consumerd_fd;
>> -
>> -    DBG("In kconsumerd_read_subbuffer (infd : %d)", infd);
>> -    /* Get the next subbuffer */
>> -    err = kernctl_get_next_subbuf(infd);
>> -    if (err != 0) {
>> -            ret = errno;
>> -            perror("Reserving sub buffer failed (everything is normal, "
>> -                            "it is due to concurrency)");
>> -            goto end;
>> -    }
>> -
>> -    switch (DEFAULT_KERNEL_CHANNEL_OUTPUT) {
>> -    case LTTNG_EVENT_SPLICE:
>> -            /* read the whole subbuffer */
>> -            err = kernctl_get_padded_subbuf_size(infd, &len);
>> -            if (err != 0) {
>> -                    ret = errno;
>> -                    perror("Getting sub-buffer len failed.");
>> -                    goto end;
>> -            }
>> -
>> -            /* splice the subbuffer to the tracefile */
>> -            ret = kconsumerd_on_read_subbuffer(kconsumerd_fd, len);
>> -            if (ret < 0) {
>> -                    /*
>> -                     * display the error but continue processing to try
>> -                     * to release the subbuffer
>> -                     */
>> -                    ERR("Error splicing to tracefile");
>> -            }
>> -            break;
>> -    case LTTNG_EVENT_MMAP:
>> -            /* read the used subbuffer size */
>> -            err = kernctl_get_subbuf_size(infd, &len);
>> -            if (err != 0) {
>> -                    ret = errno;
>> -                    perror("Getting sub-buffer len failed.");
>> -                    goto end;
>> -            }
>> -            /* write the subbuffer to the tracefile */
>> -            ret = kconsumerd_on_read_subbuffer_mmap(kconsumerd_fd, len);
>> -            if (ret < 0) {
>> -                    /*
>> -                     * display the error but continue processing to try
>> -                     * to release the subbuffer
>> -                     */
>> -                    ERR("Error writing to tracefile");
>> -            }
>> +            kconsumerd_send_error(ctx, KCONSUMERD_SPLICE_ESPIPE);
>>              break;
>> -    default:
>> -            ERR("Unknown output method");
>> -            ret = -1;
>> -    }
>> -
>> -    err = kernctl_put_next_subbuf(infd);
>> -    if (err != 0) {
>> -            ret = errno;
>> -            if (errno == EFAULT) {
>> -                    perror("Error in unreserving sub buffer\n");
>> -            } else if (errno == EIO) {
>> -                    /* Should never happen with newer LTTng versions */
>> -                    perror("Reader has been pushed by the writer, last 
>> sub-buffer corrupted.");
>> -            }
>> -            goto end;
>>      }
>>  
>>  end:
>> @@ -583,8 +492,8 @@ exit:
>>   * structures describing each fd (path name).
>>   * Returns the size of received data
>>   */
>> -static int kconsumerd_consumerd_recv_fd(int sfd,
>> -            struct pollfd *kconsumerd_sockpoll, int size,
>> +static int kconsumerd_consumerd_recv_fd(struct kconsumerd_local_data *ctx,
>> +            int sfd, struct pollfd *kconsumerd_sockpoll, int size,
>>              enum kconsumerd_command cmd_type)
>>  {
>>      struct iovec iov[1];
>> @@ -624,7 +533,7 @@ static int kconsumerd_consumerd_recv_fd(int sfd,
>>  
>>              if (ret != (size / nb_fd)) {
>>                      ERR("Received only %d, expected %d", ret, size);
>> -                    kconsumerd_send_error(KCONSUMERD_ERROR_RECV_FD);
>> +                    kconsumerd_send_error(ctx, KCONSUMERD_ERROR_RECV_FD);
>>                      goto end;
>>              }
>>  
>> @@ -632,7 +541,7 @@ static int kconsumerd_consumerd_recv_fd(int sfd,
>>              if (!cmsg) {
>>                      ERR("Invalid control message header");
>>                      ret = -1;
>> -                    kconsumerd_send_error(KCONSUMERD_ERROR_RECV_FD);
>> +                    kconsumerd_send_error(ctx, KCONSUMERD_ERROR_RECV_FD);
>>                      goto end;
>>              }
>>  
>> @@ -643,7 +552,7 @@ static int kconsumerd_consumerd_recv_fd(int sfd,
>>                              DBG("kconsumerd_add_fd %s (%d)", lkm.path_name, 
>> ((int *) CMSG_DATA(cmsg))[0]);
>>                              ret = kconsumerd_add_fd(&lkm, ((int *) 
>> CMSG_DATA(cmsg))[0]);
>>                              if (ret < 0) {
>> -                                    
>> kconsumerd_send_error(KCONSUMERD_OUTFD_ERROR);
>> +                                    kconsumerd_send_error(ctx, 
>> KCONSUMERD_OUTFD_ERROR);
>>                                      goto end;
>>                              }
>>                              break;
>> @@ -654,13 +563,13 @@ static int kconsumerd_consumerd_recv_fd(int sfd,
>>                              break;
>>                      }
>>                      /* signal the poll thread */
>> -                    tmp2 = write(kconsumerd_poll_pipe[1], "4", 1);
>> +                    tmp2 = write(ctx->kconsumerd_poll_pipe[1], "4", 1);
>>                      if (tmp2 < 0) {
>>                              perror("write kconsumerd poll");
>>                      }
>>              } else {
>>                      ERR("Didn't received any fd");
>> -                    kconsumerd_send_error(KCONSUMERD_ERROR_RECV_FD);
>> +                    kconsumerd_send_error(ctx, KCONSUMERD_ERROR_RECV_FD);
>>                      ret = -1;
>>                      goto end;
>>              }
>> @@ -686,12 +595,8 @@ void *kconsumerd_thread_poll_fds(void *data)
>>      int nb_fd = 0;
>>      char tmp;
>>      int tmp2;
>> +    struct kconsumerd_local_data *ctx = data;
>>  
>> -    ret = pipe(kconsumerd_thread_pipe);
>> -    if (ret < 0) {
>> -            perror("Error creating pipe");
>> -            goto end;
>> -    }
>>  
>>      local_kconsumerd_fd = malloc(sizeof(struct kconsumerd_fd));
>>  
>> @@ -730,10 +635,10 @@ void *kconsumerd_thread_poll_fds(void *data)
>>                              pthread_mutex_unlock(&kconsumerd_data.lock);
>>                              goto end;
>>                      }
>> -                    ret = kconsumerd_update_poll_array(&pollfd, 
>> local_kconsumerd_fd);
>> +                    ret = kconsumerd_update_poll_array(ctx, &pollfd, 
>> local_kconsumerd_fd);
>>                      if (ret < 0) {
>>                              ERR("Error in allocating pollfd or 
>> local_outfds");
>> -                            kconsumerd_send_error(KCONSUMERD_POLL_ERROR);
>> +                            kconsumerd_send_error(ctx, 
>> KCONSUMERD_POLL_ERROR);
>>                              pthread_mutex_unlock(&kconsumerd_data.lock);
>>                              goto end;
>>                      }
>> @@ -748,7 +653,7 @@ void *kconsumerd_thread_poll_fds(void *data)
>>              DBG("poll num_rdy : %d", num_rdy);
>>              if (num_rdy == -1) {
>>                      perror("Poll error");
>> -                    kconsumerd_send_error(KCONSUMERD_POLL_ERROR);
>> +                    kconsumerd_send_error(ctx, KCONSUMERD_POLL_ERROR);
>>                      goto end;
>>              } else if (num_rdy == 0) {
>>                      DBG("Polling thread timed out");
>> @@ -768,7 +673,7 @@ void *kconsumerd_thread_poll_fds(void *data)
>>               */
>>              if (pollfd[nb_fd].revents == POLLIN) {
>>                      DBG("kconsumerd_poll_pipe wake up");
>> -                    tmp2 = read(kconsumerd_poll_pipe[0], &tmp, 1);
>> +                    tmp2 = read(ctx->kconsumerd_poll_pipe[0], &tmp, 1);
>>                      if (tmp2 < 0) {
>>                              perror("read kconsumerd poll");
>>                      }
>> @@ -796,7 +701,7 @@ void *kconsumerd_thread_poll_fds(void *data)
>>                      case POLLPRI:
>>                              DBG("Urgent read on fd %d", pollfd[i].fd);
>>                              high_prio = 1;
>> -                            ret = 
>> kconsumerd_read_subbuffer(local_kconsumerd_fd[i]);
>> +                            ret = 
>> ctx->on_buffer_ready(local_kconsumerd_fd[i]);
>>                              /* it's ok to have an unavailable sub-buffer */
>>                              if (ret == EAGAIN) {
>>                                      ret = 0;
>> @@ -819,7 +724,7 @@ void *kconsumerd_thread_poll_fds(void *data)
>>                      for (i = 0; i < nb_fd; i++) {
>>                              if (pollfd[i].revents == POLLIN) {
>>                                      DBG("Normal read on fd %d", 
>> pollfd[i].fd);
>> -                                    ret = 
>> kconsumerd_read_subbuffer(local_kconsumerd_fd[i]);
>> +                                    ret = 
>> ctx->on_buffer_ready(local_kconsumerd_fd[i]);
>>                                      /* it's ok to have an unavailable 
>> subbuffer */
>>                                      if (ret == EAGAIN) {
>>                                              ret = 0;
>> @@ -842,34 +747,75 @@ end:
>>  }
>>  
>>  /*
>> - * kconsumerd_init(void)
>> + * kconsumerd_create
>>   *
>>   * initialise the necessary environnement :
>> - * - inform the polling thread to update the polling array
>> + * - create a new context
>>   * - create the poll_pipe
>>   * - create the should_quit pipe (for signal handler)
>> + * - create the thread pipe (for splice)
>> + * Takes a function pointer as argument, this function is called when data 
>> is
>> + * available on a buffer. This function is responsible to do the
>> + * kernctl_get_next_subbuf, read the data with mmap or splice depending on 
>> the
>> + * buffer configuration and then kernctl_put_next_subbuf at the end.
>> + * Returns a pointer to the new context or NULL on error.
>>   */
>> -int kconsumerd_init(void)
>> +struct kconsumerd_local_data *kconsumerd_create(
>> +            int (*buffer_ready)(struct kconsumerd_fd *kconsumerd_fd))
>>  {
>>      int ret;
>> +    struct kconsumerd_local_data *ctx;
>>  
>> -    /* need to update the polling array at init time */
>> -    kconsumerd_data.need_update = 1;
>> +    ctx = malloc(sizeof(struct kconsumerd_local_data));
>> +    if (ctx == NULL) {
>> +            perror("allocating context");
>> +            goto end;
>> +    }
>> +
>> +    ctx->on_buffer_ready = buffer_ready;
>>  
>> -    ret = pipe(kconsumerd_poll_pipe);
>> +    ret = pipe(ctx->kconsumerd_poll_pipe);
>>      if (ret < 0) {
>>              perror("Error creating poll pipe");
>> +            ctx = NULL;
>>              goto end;
>>      }
>>  
>> -    ret = pipe(kconsumerd_should_quit);
>> +    ret = pipe(ctx->kconsumerd_should_quit);
>>      if (ret < 0) {
>>              perror("Error creating recv pipe");
>> +            ctx = NULL;
>> +            goto end;
>> +    }
>> +
>> +    ret = pipe(ctx->kconsumerd_thread_pipe);
>> +    if (ret < 0) {
>> +            perror("Error creating thread pipe");
>> +            ctx = NULL;
>>              goto end;
>>      }
>>  
>>  end:
>> -    return ret;
>> +    return ctx;
>> +}
>> +
>> +/*
>> + * kconsumerd_destroy
>> + *
>> + * Close all fds associated with the instance and free the context
>> + */
>> +void kconsumerd_destroy(struct kconsumerd_local_data *ctx)
>> +{
>> +    close(ctx->kconsumerd_error_socket);
>> +    close(ctx->kconsumerd_thread_pipe[0]);
>> +    close(ctx->kconsumerd_thread_pipe[1]);
>> +    close(ctx->kconsumerd_poll_pipe[0]);
>> +    close(ctx->kconsumerd_poll_pipe[1]);
>> +    close(ctx->kconsumerd_should_quit[0]);
>> +    close(ctx->kconsumerd_should_quit[1]);
>> +    unlink(ctx->kconsumerd_command_sock_path);
>> +    free(ctx);
>> +    ctx = NULL;
>>  }
>>  
>>  /*
>> @@ -887,11 +833,12 @@ void *kconsumerd_thread_receive_fds(void *data)
>>       * avoids making blocking sockets
>>       */
>>      struct pollfd kconsumerd_sockpoll[2];
>> +    struct kconsumerd_local_data *ctx = data;
>>  
>>  
>> -    DBG("Creating command socket %s", kconsumerd_command_sock_path);
>> -    unlink(kconsumerd_command_sock_path);
>> -    client_socket = lttcomm_create_unix_sock(kconsumerd_command_sock_path);
>> +    DBG("Creating command socket %s", ctx->kconsumerd_command_sock_path);
>> +    unlink(ctx->kconsumerd_command_sock_path);
>> +    client_socket = 
>> lttcomm_create_unix_sock(ctx->kconsumerd_command_sock_path);
>>      if (client_socket < 0) {
>>              ERR("Cannot create command socket");
>>              goto end;
>> @@ -903,7 +850,7 @@ void *kconsumerd_thread_receive_fds(void *data)
>>      }
>>  
>>      DBG("Sending ready command to ltt-sessiond");
>> -    ret = kconsumerd_send_error(KCONSUMERD_COMMAND_SOCK_READY);
>> +    ret = kconsumerd_send_error(ctx, KCONSUMERD_COMMAND_SOCK_READY);
>>      if (ret < 0) {
>>              ERR("Error sending ready command to ltt-sessiond");
>>              goto end;
>> @@ -916,7 +863,7 @@ void *kconsumerd_thread_receive_fds(void *data)
>>      }
>>  
>>      /* prepare the FDs to poll : to client socket and the should_quit pipe 
>> */
>> -    kconsumerd_sockpoll[0].fd = kconsumerd_should_quit[0];
>> +    kconsumerd_sockpoll[0].fd = ctx->kconsumerd_should_quit[0];
>>      kconsumerd_sockpoll[0].events = POLLIN | POLLPRI;
>>      kconsumerd_sockpoll[1].fd = client_socket;
>>      kconsumerd_sockpoll[1].events = POLLIN | POLLPRI;
>> @@ -965,7 +912,7 @@ void *kconsumerd_thread_receive_fds(void *data)
>>              }
>>  
>>              /* we received a command to add or update fds */
>> -            ret = kconsumerd_consumerd_recv_fd(sock, kconsumerd_sockpoll,
>> +            ret = kconsumerd_consumerd_recv_fd(ctx, sock, 
>> kconsumerd_sockpoll,
>>                              tmp.payload_size, tmp.cmd_type);
>>              if (ret <= 0) {
>>                      ERR("Receiving the FD, exiting");
>> @@ -991,7 +938,7 @@ end:
>>      kconsumerd_poll_timeout = KCONSUMERD_POLL_GRACE_PERIOD;
>>  
>>      /* wake up the polling thread */
>> -    ret = write(kconsumerd_poll_pipe[1], "4", 1);
>> +    ret = write(ctx->kconsumerd_poll_pipe[1], "4", 1);
>>      if (ret < 0) {
>>              perror("poll pipe write");
>>      }
>> @@ -1001,15 +948,13 @@ end:
>>  /*
>>   *  kconsumerd_cleanup
>>   *
>> - *  Cleanup the daemon's socket on exit
>> + *  Close all the tracefiles and stream fds, should be called when all
>> + *  instances are destroyed.
>>   */
>>  void kconsumerd_cleanup(void)
>>  {
>>      struct kconsumerd_fd *iter, *tmp;
>>  
>> -    /* remove the socket file */
>> -    unlink(kconsumerd_command_sock_path);
>> -
>>      /*
>>       * close all outfd. Called when there are no more threads
>>       * running (after joining on the threads), no need to protect
>> @@ -1025,11 +970,11 @@ void kconsumerd_cleanup(void)
>>   *
>>   * Called from signal handler.
>>   */
>> -void kconsumerd_should_exit(void)
>> +void kconsumerd_should_exit(struct kconsumerd_local_data *ctx)
>>  {
>>      int ret;
>>      kconsumerd_quit = 1;
>> -    ret = write(kconsumerd_should_quit[1], "4", 1);
>> +    ret = write(ctx->kconsumerd_should_quit[1], "4", 1);
>>      if (ret < 0) {
>>              perror("write kconsumerd quit");
>>      }
>> @@ -1040,10 +985,10 @@ void kconsumerd_should_exit(void)
>>   *
>>   * send return code to ltt-sessiond
>>   */
>> -int kconsumerd_send_error(enum lttcomm_return_code cmd)
>> +int kconsumerd_send_error(struct kconsumerd_local_data *ctx, enum 
>> lttcomm_return_code cmd)
>>  {
>> -    if (kconsumerd_error_socket > 0) {
>> -            return lttcomm_send_unix_sock(kconsumerd_error_socket, &cmd,
>> +    if (ctx->kconsumerd_error_socket > 0) {
>> +            return lttcomm_send_unix_sock(ctx->kconsumerd_error_socket, 
>> &cmd,
>>                              sizeof(enum lttcomm_sessiond_command));
>>      }
>>  
>> diff --git a/liblttkconsumerd/lttkconsumerd.h 
>> b/liblttkconsumerd/lttkconsumerd.h
>> index cbdedd2..10e4a55 100644
>> --- a/liblttkconsumerd/lttkconsumerd.h
>> +++ b/liblttkconsumerd/lttkconsumerd.h
>> @@ -57,15 +57,59 @@ struct kconsumerd_fd {
>>      unsigned long max_sb_size; /* the subbuffer size for this channel */
>>  };
>>  
>> +struct kconsumerd_local_data {
>> +    /* function to call when data is available on a buffer */
>> +    int (*on_buffer_ready)(struct kconsumerd_fd *kconsumerd_fd);
>> +    /* socket to communicate errors with sessiond */
>> +    int kconsumerd_error_socket;
>> +    /* socket to exchange commands with sessiond */
>> +    char *kconsumerd_command_sock_path;
>> +    /* communication with splice */
>> +    int kconsumerd_thread_pipe[2];
>> +    /* pipe to wake the poll thread when necessary */
>> +    int kconsumerd_poll_pipe[2];
>> +    /* to let the signal handler wake up the fd receiver thread */
>> +    int kconsumerd_should_quit[2];
>> +};
>> +
>>  /*
>> - * kconsumerd_init(void)
>> + * kconsumerd_create
>>   * initialise the necessary environnement :
>> - * - inform the polling thread to update the polling array
>> + * - create a new context
>>   * - create the poll_pipe
>>   * - create the should_quit pipe (for signal handler)
>> - * returns the return code of pipe, 0 on success, -1 on error
>> + * - create the thread pipe (for splice)
>> + * Takes a function pointer as argument, this function is called when data 
>> is
>> + * available on a buffer. This function is responsible to do the
>> + * kernctl_get_next_subbuf, read the data with mmap or splice depending on 
>> the
>> + * buffer configuration and then kernctl_put_next_subbuf at the end.
>> + * Returns a pointer to the new context or NULL on error.
>> + */
>> +struct kconsumerd_local_data *kconsumerd_create(
>> +            int (*buffer_ready)(struct kconsumerd_fd *kconsumerd_fd));
>> +
>> +/*
>> + * kconsumerd_destroy
>> + * Close all fds associated with the instance and free the context
>> + */
>> +void kconsumerd_destroy(struct kconsumerd_local_data *ctx);
>> +
>> +/*
>> + * kconsumerd_on_read_subbuffer_mmap
>> + * mmap the ring buffer, read it and write the data to the tracefile.
>> + * Returns the number of bytes written
>> + */
>> +int kconsumerd_on_read_subbuffer_mmap(struct kconsumerd_local_data *ctx,
>> +            struct kconsumerd_fd *kconsumerd_fd, unsigned long len);
>> +
>> +/*
>> + * kconsumerd_on_read_subbuffer
>> + *
>> + * Splice the data from the ring buffer to the tracefile.
>> + * Returns the number of bytes spliced
>>   */
>> -int kconsumerd_init(void);
>> +int kconsumerd_on_read_subbuffer_splice(struct kconsumerd_local_data *ctx,
>> +            struct kconsumerd_fd *kconsumerd_fd, unsigned long len);
>>  
>>  /*
>>   * kconsumerd_send_error
>> @@ -73,7 +117,8 @@ int kconsumerd_init(void);
>>   * returns the return code of sendmsg : the number of bytes transmitted
>>   * or -1 on error.
>>   */
>> -int kconsumerd_send_error(enum lttcomm_return_code cmd);
>> +int kconsumerd_send_error(struct kconsumerd_local_data *ctx,
>> +            enum lttcomm_return_code cmd);
>>  
>>  /*
>>   * kconsumerd_poll_socket
>> @@ -101,7 +146,7 @@ void *kconsumerd_thread_receive_fds(void *data);
>>   * kconsumerd_should_exit
>>   * Called from signal handler to ensure a clean exit
>>   */
>> -void kconsumerd_should_exit(void);
>> +void kconsumerd_should_exit(struct kconsumerd_local_data *ctx);
>>  
>>  /*
>>   *  kconsumerd_cleanup
>> @@ -113,12 +158,12 @@ void kconsumerd_cleanup(void);
>>   * kconsumerd_set_error_socket
>>   * Set the error socket for communication with a session daemon
>>   */
>> -void kconsumerd_set_error_socket(int sock);
>> +void kconsumerd_set_error_socket(struct kconsumerd_local_data *ctx, int 
>> sock);
>>  
>>  /*
>>   * kconsumerd_set_command_socket_path
>>   * Set the command socket path for communication with a session daemon
>>   */
>> -void kconsumerd_set_command_socket_path(char *sock);
>> +void kconsumerd_set_command_socket_path(struct kconsumerd_local_data *ctx, 
>> char *sock);
>>  
>>  #endif /* _LIBLTTKCONSUMERD_H */
>> diff --git a/ltt-kconsumerd/ltt-kconsumerd.c 
>> b/ltt-kconsumerd/ltt-kconsumerd.c
>> index 1e2841c..64c5ccf 100644
>> --- a/ltt-kconsumerd/ltt-kconsumerd.c
>> +++ b/ltt-kconsumerd/ltt-kconsumerd.c
>> @@ -55,6 +55,9 @@ static const char *progname;
>>  char command_sock_path[PATH_MAX]; /* Global command socket path */
>>  char error_sock_path[PATH_MAX]; /* Global error path */
>>  
>> +/* the liblttkconsumerd context */
>> +struct kconsumerd_local_data *ctx;
>> +
>>  /*
>>   *  sighandler
>>   *
>> @@ -67,7 +70,7 @@ static void sighandler(int sig)
>>              return;
>>      }
>>  
>> -    kconsumerd_should_exit();
>> +    kconsumerd_should_exit(ctx);
>>  }
>>  
>>  /*
>> @@ -190,6 +193,86 @@ static void parse_args(int argc, char **argv)
>>      }
>>  }
>>  
>> +/*
>> + * read_subbuffer
>> + *
>> + * Consume data on a file descriptor and write it on a trace file
>> + */
>> +static int read_subbuffer(struct kconsumerd_fd *kconsumerd_fd)
>> +{
>> +    unsigned long len;
>> +    int err;
>> +    long ret = 0;
>> +    int infd = kconsumerd_fd->consumerd_fd;
>> +
>> +    DBG("In kconsumerd_read_subbuffer (infd : %d)", infd);
>> +    /* Get the next subbuffer */
>> +    err = kernctl_get_next_subbuf(infd);
>> +    if (err != 0) {
>> +            ret = errno;
>> +            perror("Reserving sub buffer failed (everything is normal, "
>> +                            "it is due to concurrency)");
>> +            goto end;
>> +    }
>> +
>> +    switch (DEFAULT_KERNEL_CHANNEL_OUTPUT) {
>> +            case LTTNG_EVENT_SPLICE:
>> +                    /* read the whole subbuffer */
>> +                    err = kernctl_get_padded_subbuf_size(infd, &len);
>> +                    if (err != 0) {
>> +                            ret = errno;
>> +                            perror("Getting sub-buffer len failed.");
>> +                            goto end;
>> +                    }
>> +
>> +                    /* splice the subbuffer to the tracefile */
>> +                    ret = kconsumerd_on_read_subbuffer_splice(ctx, 
>> kconsumerd_fd, len);
>> +                    if (ret < 0) {
>> +                            /*
>> +                             * display the error but continue processing to 
>> try
>> +                             * to release the subbuffer
>> +                             */
>> +                            ERR("Error splicing to tracefile");
>> +                    }
>> +                    break;
>> +            case LTTNG_EVENT_MMAP:
>> +                    /* read the used subbuffer size */
>> +                    err = kernctl_get_subbuf_size(infd, &len);
>> +                    if (err != 0) {
>> +                            ret = errno;
>> +                            perror("Getting sub-buffer len failed.");
>> +                            goto end;
>> +                    }
>> +                    /* write the subbuffer to the tracefile */
>> +                    ret = kconsumerd_on_read_subbuffer_mmap(ctx, 
>> kconsumerd_fd, len);
>> +                    if (ret < 0) {
>> +                            /*
>> +                             * display the error but continue processing to 
>> try
>> +                             * to release the subbuffer
>> +                             */
>> +                            ERR("Error writing to tracefile");
>> +                    }
>> +                    break;
>> +            default:
>> +                    ERR("Unknown output method");
>> +                    ret = -1;
>> +    }
>> +
>> +    err = kernctl_put_next_subbuf(infd);
>> +    if (err != 0) {
>> +            ret = errno;
>> +            if (errno == EFAULT) {
>> +                    perror("Error in unreserving sub buffer\n");
>> +            } else if (errno == EIO) {
>> +                    /* Should never happen with newer LTTng versions */
>> +                    perror("Reader has been pushed by the writer, last 
>> sub-buffer corrupted.");
>> +            }
>> +            goto end;
>> +    }
>> +
>> +end:
>> +    return ret;
>> +}
>>  
>>  /*
>>   * main
>> @@ -217,7 +300,13 @@ int main(int argc, char **argv)
>>              snprintf(command_sock_path, PATH_MAX,
>>                              KCONSUMERD_CMD_SOCK_PATH);
>>      }
>> -    kconsumerd_set_command_socket_path(command_sock_path);
>> +    /* create the pipe to wake to receiving thread when needed */
>> +    ctx = kconsumerd_create(read_subbuffer);
>> +    if (ctx == NULL) {
>> +            goto error;
>> +    }
>> +
>> +    kconsumerd_set_command_socket_path(ctx, command_sock_path);
>>      if (strlen(error_sock_path) == 0) {
>>              snprintf(error_sock_path, PATH_MAX,
>>                              KCONSUMERD_ERR_SOCK_PATH);
>> @@ -227,12 +316,6 @@ int main(int argc, char **argv)
>>              goto error;
>>      }
>>  
>> -    /* create the pipe to wake to receiving thread when needed */
>> -    ret = kconsumerd_init();
>> -    if (ret < 0) {
>> -            goto end;
>> -    }
>> -
>>      /* Connect to the socket created by ltt-sessiond to report errors */
>>      DBG("Connecting to error socket %s", error_sock_path);
>>      ret = lttcomm_connect_unix_sock(error_sock_path);
>> @@ -240,11 +323,11 @@ int main(int argc, char **argv)
>>      if (ret < 0) {
>>              WARN("Cannot connect to error socket, is ltt-sessiond started 
>> ?");
>>      }
>> -    kconsumerd_set_error_socket(ret);
>> +    kconsumerd_set_error_socket(ctx, ret);
>>  
>>      /* Create the thread to manage the receive of fd */
>>      ret = pthread_create(&threads[0], NULL, kconsumerd_thread_receive_fds,
>> -                    (void *) NULL);
>> +                    (void *) ctx);
>>      if (ret != 0) {
>>              perror("pthread_create");
>>              goto error;
>> @@ -252,7 +335,7 @@ int main(int argc, char **argv)
>>  
>>      /* Create thread to manage the polling/writing of traces */
>>      ret = pthread_create(&threads[1], NULL, kconsumerd_thread_poll_fds,
>> -                    (void *) NULL);
>> +                    (void *) ctx);
>>      if (ret != 0) {
>>              perror("pthread_create");
>>              goto error;
>> @@ -266,14 +349,15 @@ int main(int argc, char **argv)
>>              }
>>      }
>>      ret = EXIT_SUCCESS;
>> -    kconsumerd_send_error(KCONSUMERD_EXIT_SUCCESS);
>> +    kconsumerd_send_error(ctx, KCONSUMERD_EXIT_SUCCESS);
>>      goto end;
>>  
>>  error:
>>      ret = EXIT_FAILURE;
>> -    kconsumerd_send_error(KCONSUMERD_EXIT_FAILURE);
>> +    kconsumerd_send_error(ctx, KCONSUMERD_EXIT_FAILURE);
>>  
>>  end:
>> +    kconsumerd_destroy(ctx);
>>      kconsumerd_cleanup();
>>  
>>      return ret;
>> -- 
>> 1.7.4.1
>>
> 

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