fsm: Add VTY introspection of osmo_fsm and their instances

Change-Id: I89212e4f149f019099115a85bab353c04170df90
diff --git a/src/vty/fsm_vty.c b/src/vty/fsm_vty.c
new file mode 100644
index 0000000..422de9d
--- /dev/null
+++ b/src/vty/fsm_vty.c
@@ -0,0 +1,177 @@
+/* Osmocom FSM introspection via VTY */
+/* (C) 2016 by Harald Welte <laforge@gnumonks.org>
+ * All Rights Reserved
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "../../config.h"
+
+#include <osmocom/vty/command.h>
+#include <osmocom/vty/buffer.h>
+#include <osmocom/vty/vty.h>
+#include <osmocom/vty/telnet_interface.h>
+#include <osmocom/vty/misc.h>
+
+#include <osmocom/core/fsm.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/linuxlist.h>
+
+/* we don't want to add this to a public header file; this is simply
+ * exported by libosmocore and used by libmsomvty but not for public
+ * consumption. */
+extern struct llist_head osmo_g_fsms;
+
+/*! \brief Print information about a FSM [class] to the given VTY
+ *  \param vty The VTY to which to print
+ *  \param[in] fsm The FSM class to print
+ */
+void vty_out_fsm(struct vty *vty, struct osmo_fsm *fsm)
+{
+	unsigned int i;
+	const struct value_string *evt_name;
+
+	vty_out(vty, "FSM Name: '%s', Log Subsys: '%s'%s", fsm->name,
+		log_category_name(fsm->log_subsys), VTY_NEWLINE);
+	/* list the events */
+	for (evt_name = fsm->event_names; evt_name->str != NULL; evt_name++) {
+		vty_out(vty, " Event %02u (0x%08x): '%s'%s", evt_name->value,
+			(1 << evt_name->value), evt_name->str, VTY_NEWLINE);
+	}
+	/* list the states */
+	vty_out(vty, " Number of States: %u%s", fsm->num_states, VTY_NEWLINE);
+	for (i = 0; i < fsm->num_states; i++) {
+		const struct osmo_fsm_state *state = &fsm->states[i];
+		vty_out(vty, "  State %-20s InEvtMask: 0x%08x, OutStateMask: 0x%08x%s",
+			state->name, state->in_event_mask, state->out_state_mask,
+			VTY_NEWLINE);
+	}
+}
+
+/*! \brief Print a FSM instance to the given VTY
+ *  \param vty The VTY to which to print
+ *  \param[in] fsmi The FSM instance to print
+ */
+void vty_out_fsm_inst(struct vty *vty, struct osmo_fsm_inst *fsmi)
+{
+	struct osmo_fsm_inst *child;
+
+	vty_out(vty, "FSM Instance Name: '%s', ID: '%s'%s",
+		fsmi->name, fsmi->id, VTY_NEWLINE);
+	vty_out(vty, " Log-Level: '%s', State: '%s'%s",
+		log_level_str(fsmi->log_level),
+		osmo_fsm_state_name(fsmi->fsm, fsmi->state),
+		VTY_NEWLINE);
+	if (fsmi->T)
+		vty_out(vty, " Timer: %u%s", fsmi->T, VTY_NEWLINE);
+	if (fsmi->proc.parent) {
+		vty_out(vty, " Parent: '%s', Term-Event: '%s'%s",
+			fsmi->proc.parent->name,
+			osmo_fsm_event_name(fsmi->proc.parent->fsm,
+					    fsmi->proc.parent_term_event),
+			VTY_NEWLINE);
+	}
+	llist_for_each_entry(child, &fsmi->proc.children, list) {
+		vty_out(vty, " Child: '%s'%s", child->name, VTY_NEWLINE);
+	}
+}
+
+#define SH_FSM_STR	SHOW_STR "Show information about finite state machines\n"
+#define SH_FSMI_STR	SHOW_STR "Show information about finite state machine instances\n"
+
+DEFUN(show_fsms, show_fsms_cmd,
+	"show fsm all",
+	SH_FSM_STR
+	"Display a list of all registered finite state machines\n")
+{
+	struct osmo_fsm *fsm;
+
+	llist_for_each_entry(fsm, &osmo_g_fsms, list)
+		vty_out_fsm(vty, fsm);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_fsm, show_fsm_cmd,
+	"show fsm NAME",
+	SH_FSM_STR
+	"Display information about a single named finite state machine\n")
+{
+	struct osmo_fsm *fsm;
+
+	fsm = osmo_fsm_find_by_name(argv[0]);
+	if (!fsm) {
+		vty_out(vty, "Error: FSM with name '%s' doesn't exist!%s",
+			argv[0], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	vty_out_fsm(vty, fsm);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_fsm_insts, show_fsm_insts_cmd,
+	"show fsm-instances all",
+	SH_FSMI_STR
+	"Display a list of all FSM instances of all finite state machine")
+{
+	struct osmo_fsm *fsm;
+
+	llist_for_each_entry(fsm, &osmo_g_fsms, list) {
+		struct osmo_fsm_inst *fsmi;
+		llist_for_each_entry(fsmi, &fsm->instances, list)
+			vty_out_fsm_inst(vty, fsmi);
+	}
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_fsm_inst, show_fsm_inst_cmd,
+	"show fsm-instances NAME",
+	SH_FSMI_STR
+	"Display a list of all FSM instances of the named finite state machine")
+{
+	struct osmo_fsm *fsm;
+	struct osmo_fsm_inst *fsmi;
+
+	fsm = osmo_fsm_find_by_name(argv[0]);
+	if (!fsm) {
+		vty_out(vty, "Error: FSM with name '%s' doesn't exist!%s",
+			argv[0], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	llist_for_each_entry(fsmi, &fsm->instances, list)
+		vty_out_fsm_inst(vty, fsmi);
+
+	return CMD_SUCCESS;
+}
+
+/*! \brief Install VTY commands for FSM introspection
+ *  This installs a couple of VTY commands for introspection of FSM
+ *  classes as well as FSM instances. Call this once from your
+ *  application if you want to support those commands. */
+void osmo_fsm_vty_add_cmds(void)
+{
+	install_element_ve(&show_fsm_cmd);
+	install_element_ve(&show_fsms_cmd);
+	install_element_ve(&show_fsm_inst_cmd);
+	install_element_ve(&show_fsm_insts_cmd);
+}