[lttng-dev] RFC - Triggers in lttng-tools

[Thibault, Daniel]

Based on http://lists.lttng.org/pipermail/lttng-dev/attachments/20130411/7256c589/attachment-0001.txt

> The main idea of triggers is for the user to be able to set an action on a
> session triggered by a certain event of the system. To illustrace the concept,
> here is an example that we will actually propose.

[...] To illustrate the concept [...]

> Let say an application is being traced and on core dump, we would like to
> automatically snapshot the session and proceed to analysis later on.

Let's say an [...] and, on core dump, we [...]
or
Say an [...] and, on core dump, we [...]

> The idea would be to set a "trigger" named OnAnyCoreDump for the session. Any
> coredump detected using /proc/sys/kernel/core_pattern will send a notification
> to the session daemon and trigger the user defined action.

[...] the user-defined action.

> First, a trigger command is needed and goes as followed.

[...] and goes as follows:

> For the example showed in the Motivation section, the <WHAT> is OnAnyCoreDump
> and the <ACTION> is to take a snapshot of the session where this trigger is
> set.

For the example shown in [...]

> In order to use the notify socket, the message protocol is detailed as
> followed.

[...] detailed as follows:

> Now to fire it up by being let say in a small program set in
> /proc/.../core_pattern.

Now to fire it up by being let's say in a small [...]

Daniel U. Thibault
R & D pour la défense Canada - Valcartier (RDDC Valcartier) / Defence R&D Canada - Valcartier (DRDC Valcartier)
Cyber sécurité pour les missions essentielles (CME) / Mission Critical Cyber Security (MCCS)
Protection des systèmes et contremesures (PSC) / Systems Protection & Countermeasures (SPC)
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Gouvernement du Canada / Government of Canada
<http://www.valcartier.drdc-rddc.gc.ca/>