[lttng-dev] [PATCH lttng-tools] Fix: kernel track/untrack error handling

[Jérémie Galarneau]

Merged, thanks!

While testing/reviewing this fix, I noticed that untracking a user
space PID before enabling one (leaving the ust session pid_tracker
uninitialized) would result in an "Invalid parameter" error being
returned to the client (see bug #931).

The following commit addresses the problem:

commit b894343d659df2f6aa9ed50532fd4d8c0757e089
Author: Jérémie Galarneau <jeremie.galarneau at efficios.com>
Date:   Fri Sep 4 17:34:44 2015 -0400

    Fix: Invalid parameter error reported when untracking PID

    The LTTng client reports an "Invalid parameter" error if a PID is
    untracked from the userspace domain before any PID is tracked in that
    domain.

    Fixes #931

    Signed-off-by: Jérémie Galarneau <jeremie.galarneau at efficios.com>


Jérémie

On Wed, Sep 2, 2015 at 10:45 AM, Mathieu Desnoyers
<mathieu.desnoyers at efficios.com> wrote:
> Fixes: #918
>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> ---
>  src/bin/lttng-sessiond/kernel.c | 34 ++++++++++++++++++++++++++++++++--
>  1 file changed, 32 insertions(+), 2 deletions(-)
>
> diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
> index 570747f..381b83e 100644
> --- a/src/bin/lttng-sessiond/kernel.c
> +++ b/src/bin/lttng-sessiond/kernel.c
> @@ -379,16 +379,46 @@ error:
>
>  int kernel_track_pid(struct ltt_kernel_session *session, int pid)
>  {
> +       int ret;
> +
>         DBG("Kernel track PID %d for session id %" PRIu64 ".",
>                         pid, session->id);
> -       return kernctl_track_pid(session->fd, pid);
> +       ret = kernctl_track_pid(session->fd, pid);
> +       if (!ret) {
> +               return LTTNG_OK;
> +       }
> +       switch (errno) {
> +       case EINVAL:
> +               return LTTNG_ERR_INVALID;
> +       case ENOMEM:
> +               return LTTNG_ERR_NOMEM;
> +       case EEXIST:
> +               return LTTNG_ERR_PID_TRACKED;
> +       default:
> +               return LTTNG_ERR_UNK;
> +       }
>  }
>
>  int kernel_untrack_pid(struct ltt_kernel_session *session, int pid)
>  {
> +       int ret;
> +
>         DBG("Kernel untrack PID %d for session id %" PRIu64 ".",
>                         pid, session->id);
> -       return kernctl_untrack_pid(session->fd, pid);
> +       ret = kernctl_untrack_pid(session->fd, pid);
> +       if (!ret) {
> +               return LTTNG_OK;
> +       }
> +       switch (errno) {
> +       case EINVAL:
> +               return LTTNG_ERR_INVALID;
> +       case ENOMEM:
> +               return LTTNG_ERR_NOMEM;
> +       case ENOENT:
> +               return LTTNG_ERR_PID_NOT_TRACKED;
> +       default:
> +               return LTTNG_ERR_UNK;
> +       }
>  }
>
>  ssize_t kernel_list_tracker_pids(struct ltt_kernel_session *session,
> --
> 2.1.4
>



-- 
Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com