From d1f5793b5e89426927d57cff7f6951e0c2e29d92 Mon Sep 17 00:00:00 2001 From: Philipp Maier Date: Wed, 14 Feb 2018 18:20:07 +0100 Subject: fsm: allow graceful exit on FSM termination The function _osmo_fsm_inst_term() terminates all child FSMs befor it calls fi->fsm_cleanup(). This prevents the cleanup callback to perform last actions on the child FSMs (e.g. osmo_fsm_inst_unlink_parent()). - Since moving the cleanup callack to the beginning of the function would alter the termination behavior and possibly cause malfunction in already existing implementation that use OSMO fsm, a new optional callback that is called immediately at the beginning of the terminatopn process is added. Change-Id: I0fdda9fe994753f975a658c0f3fb3615949cc8bb Closes: OS#2915 --- src/fsm.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'src') diff --git a/src/fsm.c b/src/fsm.c index a1273624..176aa8ab 100644 --- a/src/fsm.c +++ b/src/fsm.c @@ -298,7 +298,11 @@ struct osmo_fsm_inst *osmo_fsm_inst_alloc_child(struct osmo_fsm *fsm, /*! unlink child FSM from its parent FSM. * \param[in] fi Descriptor of the child FSM to unlink. - * \param[in] ctx New talloc context */ + * \param[in] ctx New talloc context + * + * Never call this function from the cleanup callback, because at that time + * the child FSMs will already be terminated. If unlinking should be performed + * on FSM termination, use the grace callback instead. */ void osmo_fsm_inst_unlink_parent(struct osmo_fsm_inst *fi, void *ctx) { if (fi->proc.parent) { @@ -312,7 +316,10 @@ void osmo_fsm_inst_unlink_parent(struct osmo_fsm_inst *fi, void *ctx) /*! change parent instance of an FSM. * \param[in] fi Descriptor of the to-be-allocated FSM. * \param[in] new_parent New parent FSM instance. - * \param[in] new_parent_term_event Event to be sent to parent when terminating. */ + * \param[in] new_parent_term_event Event to be sent to parent when terminating. + * + * Never call this function from the cleanup callback! + * (see also osmo_fsm_inst_unlink_parent()).*/ void osmo_fsm_inst_change_parent(struct osmo_fsm_inst *fi, struct osmo_fsm_inst *new_parent, uint32_t new_parent_term_event) @@ -528,6 +535,10 @@ void _osmo_fsm_inst_term(struct osmo_fsm_inst *fi, LOGPFSMSRC(fi, file, line, "Terminating (cause = %s)\n", osmo_fsm_term_cause_name(cause)); + /* graceful exit (optional) */ + if (fi->fsm->pre_term) + fi->fsm->pre_term(fi, cause); + _osmo_fsm_inst_term_children(fi, OSMO_FSM_TERM_PARENT, NULL, file, line); -- cgit v1.2.3