/*
 * (C) 2009-2010 by Harald Welte <laforge@gnumonks.org>
 * (C) 2009-2014 by Holger Hans Peter Freyther
 * All Rights Reserved
 *
 * SPDX-License-Identifier: GPL-2.0+
 *
 * 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/core/talloc.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/utils.h>
#include <osmocom/core/strrb.h>
#include <osmocom/core/loggingrb.h>
#include <osmocom/core/gsmtap.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/logging.h>

#define LOG_STR "Configure logging sub-system\n"

/*! \file logging_vty.c
 *  Configuration of logging from VTY
 *
 *  This module implements
 *  - functions that permit configuration of the libosmocore logging
 *    framework from VTY commands in the configure -> logging node.
 *
 *  - functions that permit logging *to* a VTY session.  Basically each
 *    VTY session gets its own log target, with configurable
 *    per-subsystem log levels.  This is performed internally via the
 *    \ref log_target_create_vty function.
 *
 *  You have to call \ref logging_vty_add_cmds from your application
 *  once to enable both of the above.
 *
 */

extern const struct log_info *osmo_log_info;

static void _vty_output(struct log_target *tgt,
			unsigned int level, const char *line)
{
	struct vty *vty = tgt->tgt_vty.vty;
	vty_out(vty, "%s", line);
	/* This is an ugly hack, but there is no easy way... */
	if (strchr(line, '\n'))
		vty_out(vty, "\r");
}

struct log_target *log_target_create_vty(struct vty *vty)
{
	struct log_target *target;

	target = log_target_create();
	if (!target)
		return NULL;

	target->tgt_vty.vty = vty;
	target->output = _vty_output;
	return target;
}

DEFUN(enable_logging,
      enable_logging_cmd,
      "logging enable",
	LOGGING_STR
      "Enables logging to this vty\n")
{
	struct telnet_connection *conn;

	conn = (struct telnet_connection *) vty->priv;
	if (conn->dbg) {
		vty_out(vty, "Logging already enabled.%s", VTY_NEWLINE);
		return CMD_WARNING;
	}

	conn->dbg = log_target_create_vty(vty);
	if (!conn->dbg)
		return CMD_WARNING;

	log_add_target(conn->dbg);
	return CMD_SUCCESS;
}

struct log_target *osmo_log_vty2tgt(struct vty *vty)
{
	struct telnet_connection *conn;

	if (vty->node == CFG_LOG_NODE)
		return vty->index;


	conn = (struct telnet_connection *) vty->priv;
	if (!conn->dbg)
		vty_out(vty, "Logging was not enabled.%s", VTY_NEWLINE);

	return conn->dbg;
}

DEFUN(logging_fltr_all,
      logging_fltr_all_cmd,
      "logging filter all (0|1)",
	LOGGING_STR FILTER_STR
	"Do you want to log all messages?\n"
	"Only print messages matched by other filters\n"
	"Bypass filter and print all messages\n")
{
	struct log_target *tgt = osmo_log_vty2tgt(vty);

	if (!tgt)
		return CMD_WARNING;

	log_set_all_filter(tgt, atoi(argv[0]));
	return CMD_SUCCESS;
}

DEFUN(logging_use_clr,
      logging_use_clr_cmd,
      "logging color (0|1)",
	LOGGING_STR "Configure color-printing for log messages\n"
      "Don't use color for printing messages\n"
      "Use color for printing messages\n")
{
	struct log_target *tgt = osmo_log_vty2tgt(vty);

	if (!tgt)
		return CMD_WARNING;

	log_set_use_color(tgt, atoi(argv[0]));
	return CMD_SUCCESS;
}

DEFUN(logging_prnt_timestamp,
      logging_prnt_timestamp_cmd,
      "logging timestamp (0|1)",
	LOGGING_STR "Configure log message timestamping\n"
	"Don't prefix each log message\n"
	"Prefix each log message with current timestamp\n")
{
	struct log_target *tgt = osmo_log_vty2tgt(vty);

	if (!tgt)
		return CMD_WARNING;

	log_set_print_timestamp(tgt, atoi(argv[0]));
	return CMD_SUCCESS;
}

DEFUN(logging_prnt_ext_timestamp,
      logging_prnt_ext_timestamp_cmd,
      "logging print extended-timestamp (0|1)",
	LOGGING_STR "Log output settings\n"
	"Configure log message timestamping\n"
	"Don't prefix each log message\n"
	"Prefix each log message with current timestamp with YYYYMMDDhhmmssnnn\n")
{
	struct log_target *tgt = osmo_log_vty2tgt(vty);

	if (!tgt)
		return CMD_WARNING;

	log_set_print_extended_timestamp(tgt, atoi(argv[0]));
	return CMD_SUCCESS;
}

DEFUN(logging_prnt_cat,
      logging_prnt_cat_cmd,
      "logging print category (0|1)",
	LOGGING_STR "Log output settings\n"
	"Configure log message\n"
	"Don't prefix each log message\n"
	"Prefix each log message with category/subsystem name\n")
{
	struct log_target *tgt = osmo_log_vty2tgt(vty);

	if (!tgt)
		return CMD_WARNING;

	log_set_print_category(tgt, atoi(argv[0]));
	return CMD_SUCCESS;
}

DEFUN(logging_prnt_cat_hex,
      logging_prnt_cat_hex_cmd,
      "logging print category-hex (0|1)",
	LOGGING_STR "Log output settings\n"
	"Configure log message\n"
	"Don't prefix each log message\n"
	"Prefix each log message with category/subsystem nr in hex ('<000b>')\n")
{
	struct log_target *tgt = osmo_log_vty2tgt(vty);

	if (!tgt)
		return CMD_WARNING;

	log_set_print_category_hex(tgt, atoi(argv[0]));
	return CMD_SUCCESS;
}

DEFUN(logging_prnt_level,
      logging_prnt_level_cmd,
      "logging print level (0|1)",
      LOGGING_STR "Log output settings\n"
      "Configure log message\n"
      "Don't prefix each log message\n"
      "Prefix each log message with the log level name\n")
{
	struct log_target *tgt = osmo_log_vty2tgt(vty);

	if (!tgt)
		return CMD_WARNING;

	log_set_print_level(tgt, atoi(argv[0]));
	return CMD_SUCCESS;
}

static const struct value_string logging_print_file_args[] = {
	{ LOG_FILENAME_NONE, "0" },
	{ LOG_FILENAME_PATH, "1" },
	{ LOG_FILENAME_BASENAME, "basename" },
	{ 0, NULL }
};

DEFUN(logging_prnt_file,
      logging_prnt_file_cmd,
      "logging print file (0|1|basename)",
      LOGGING_STR "Log output settings\n"
      "Configure log message\n"
      "Don't prefix each log message\n"
      "Prefix each log message with the source file and line\n"
      "Prefix each log message with the source file's basename (strip leading paths) and line\n")
{
	struct log_target *tgt = osmo_log_vty2tgt(vty);

	if (!tgt)
		return CMD_WARNING;

	log_set_print_filename2(tgt, get_string_value(logging_print_file_args, argv[0]));
	return CMD_SUCCESS;
}

DEFUN(logging_level,
      logging_level_cmd,
      NULL, /* cmdstr is dynamically set in logging_vty_add_cmds(). */
      NULL) /* same thing for helpstr. */
{
	int category = log_parse_category(argv[0]);
	int level = log_parse_level(argv[1]);
	struct log_target *tgt = osmo_log_vty2tgt(vty);

	if (!tgt)
		return CMD_WARNING;

	if (level < 0) {
		vty_out(vty, "Invalid level `%s'%s", argv[1], VTY_NEWLINE);
		return CMD_WARNING;
	}

	if (strcmp(argv[1], "everything") == 0) { /* FIXME: remove this check once 'everything' is phased out */
		vty_out(vty, "%% Ignoring deprecated logging level %s%s", argv[1], VTY_NEWLINE);
		return CMD_SUCCESS;
	}

	/* Check for special case where we want to set global log level */
	if (!strcmp(argv[0], "all")) {
		log_set_log_level(tgt, level);
		return CMD_SUCCESS;
	}

	if (category < 0) {
		vty_out(vty, "Invalid category `%s'%s", argv[0], VTY_NEWLINE);
		return CMD_WARNING;
	}

	tgt->categories[category].enabled = 1;
	tgt->categories[category].loglevel = level;

	return CMD_SUCCESS;
}

DEFUN(logging_set_category_mask,
      logging_set_category_mask_cmd,
      "logging set-log-mask MASK",
	LOGGING_STR
      "Set the logmask of this logging target\n"
      "List of logging categories to log, e.g. 'abc:mno:xyz'. Available log categories depend on the specific"
      " application, refer to the 'logging level' command. Optionally add individual log levels like"
      " 'abc,1:mno,3:xyz,5', where the level numbers are"
      " " OSMO_STRINGIFY(LOGL_DEBUG) "=" OSMO_STRINGIFY_VAL(LOGL_DEBUG)
      " " OSMO_STRINGIFY(LOGL_INFO) "=" OSMO_STRINGIFY_VAL(LOGL_INFO)
      " " OSMO_STRINGIFY(LOGL_NOTICE) "=" OSMO_STRINGIFY_VAL(LOGL_NOTICE)
      " " OSMO_STRINGIFY(LOGL_ERROR) "=" OSMO_STRINGIFY_VAL(LOGL_ERROR)
      " " OSMO_STRINGIFY(LOGL_FATAL) "=" OSMO_STRINGIFY_VAL(LOGL_FATAL)
      "\n")
{
	struct log_target *tgt = osmo_log_vty2tgt(vty);

	if (!tgt)
		return CMD_WARNING;

	log_parse_category_mask(tgt, argv[0]);
	return CMD_SUCCESS;
}

ALIAS_DEPRECATED(logging_set_category_mask,
		 logging_set_category_mask_old_cmd,
		 "logging set log mask MASK",
		 LOGGING_STR
		 "Decide which categories to output.\n"
		 "Log commands\n" "Mask commands\n"
		 "'set log mask' is deprecated, please refer to the docs of 'set-log-mask' instead\n");


DEFUN(diable_logging,
      disable_logging_cmd,
      "logging disable",
	LOGGING_STR
      "Disables logging to this vty\n")
{
	struct log_target *tgt = osmo_log_vty2tgt(vty);
	struct telnet_connection *conn = (struct telnet_connection *) vty->priv;

	if (!tgt)
		return CMD_WARNING;

	log_del_target(tgt);
	talloc_free(tgt);
	conn->dbg = NULL;

	return CMD_SUCCESS;
}

static void vty_print_logtarget(struct vty *vty, const struct log_info *info,
				const struct log_target *tgt)
{
	unsigned int i;

	vty_out(vty, " Global Loglevel: %s%s",
		log_level_str(tgt->loglevel), VTY_NEWLINE);
	vty_out(vty, " Use color: %s, Print Timestamp: %s%s",
		tgt->use_color ? "On" : "Off",
		tgt->print_timestamp ? "On" : "Off", VTY_NEWLINE);

	vty_out(vty, " Log Level specific information:%s", VTY_NEWLINE);

	for (i = 0; i < info->num_cat; i++) {
		const struct log_category *cat = &tgt->categories[i];
		/* Skip categories that were not initialized */
		if (!info->cat[i].name)
			continue;
		vty_out(vty, "  %-10s %-10s %-8s %s%s",
			info->cat[i].name+1, log_level_str(cat->loglevel),
			cat->enabled ? "Enabled" : "Disabled",
 			info->cat[i].description,
			VTY_NEWLINE);
	}

	vty_out(vty, " Log Filter 'ALL': %s%s",
		tgt->filter_map & (1 << LOG_FLT_ALL) ? "Enabled" : "Disabled",
		VTY_NEWLINE);

	/* print application specific filters */
	if (info->print_fn)
		info->print_fn(vty, info, tgt);
}

#define SHOW_LOG_STR "Show current logging configuration\n"

DEFUN(show_logging_vty,
	show_logging_vty_cmd,
	"show logging vty",
	SHOW_STR SHOW_LOG_STR
	"Show current logging configuration for this vty\n")
{
	struct log_target *tgt = osmo_log_vty2tgt(vty);

	if (!tgt)
		return CMD_WARNING;

	vty_print_logtarget(vty, osmo_log_info, tgt);

	return CMD_SUCCESS;
}

DEFUN(show_alarms,
	show_alarms_cmd,
	"show alarms",
	SHOW_STR SHOW_LOG_STR
	"Show the contents of the logging ringbuffer\n")
{
	int i, num_alarms;
	struct osmo_strrb *rb;
	struct log_target *tgt = log_target_find(LOG_TGT_TYPE_STRRB, NULL);
	if (!tgt) {
		vty_out(vty, "%% No alarms, run 'log alarms <2-32700>'%s",
			VTY_NEWLINE);
		return CMD_WARNING;
	}

	rb = tgt->tgt_rb.rb;
	num_alarms = osmo_strrb_elements(rb);

	vty_out(vty, "%% Showing %i alarms%s", num_alarms, VTY_NEWLINE);

	for (i = 0; i < num_alarms; i++)
		vty_out(vty, "%% %s%s", osmo_strrb_get_nth(rb, i),
			VTY_NEWLINE);

	return CMD_SUCCESS;
}

gDEFUN(cfg_description, cfg_description_cmd,
	"description .TEXT",
	"Save human-readable description of the object\n"
	"Text until the end of the line\n")
{
	char **dptr = vty->index_sub;

	if (!dptr) {
		vty_out(vty, "vty->index_sub == NULL%s", VTY_NEWLINE);
		return CMD_WARNING;
	}

	if (*dptr)
		talloc_free(*dptr);
	*dptr = argv_concat(argv, argc, 0);
	if (!*dptr)
		return CMD_WARNING;

	return CMD_SUCCESS;
}

gDEFUN(cfg_no_description, cfg_no_description_cmd,
	"no description",
	NO_STR
	"Remove description of the object\n")
{
	char **dptr = vty->index_sub;

	if (!dptr) {
		vty_out(vty, "vty->index_sub == NULL%s", VTY_NEWLINE);
		return CMD_WARNING;
	}

	if (*dptr) {
		talloc_free(*dptr);
		*dptr = NULL;
	}

	return CMD_SUCCESS;
}

/* Support for configuration of log targets != the current vty */

struct cmd_node cfg_log_node = {
	CFG_LOG_NODE,
	"%s(config-log)# ",
	1
};

#ifdef HAVE_SYSLOG_H

#include <syslog.h>

static const int local_sysl_map[] = {
	[0] = LOG_LOCAL0,
	[1] = LOG_LOCAL1,
	[2] = LOG_LOCAL2,
	[3] = LOG_LOCAL3,
	[4] = LOG_LOCAL4,
	[5] = LOG_LOCAL5,
	[6] = LOG_LOCAL6,
	[7] = LOG_LOCAL7
};

/* From VTY core code */
extern struct host host;

static int _cfg_log_syslog(struct vty *vty, int facility)
{
	struct log_target *tgt;

	/* First delete the old syslog target, if any */
	tgt = log_target_find(LOG_TGT_TYPE_SYSLOG, NULL);
	if (tgt)
		log_target_destroy(tgt);

	tgt = log_target_create_syslog(host.app_info->name, 0, facility);
	if (!tgt) {
		vty_out(vty, "%% Unable to open syslog%s", VTY_NEWLINE);
		return CMD_WARNING;
	}
	log_add_target(tgt);

	vty->index = tgt;
	vty->node = CFG_LOG_NODE;

	return CMD_SUCCESS;
}

DEFUN(cfg_log_syslog_local, cfg_log_syslog_local_cmd,
      "log syslog local <0-7>",
	LOG_STR "Logging via syslog\n" "Syslog LOCAL facility\n"
	"Local facility number\n")
{
	int local = atoi(argv[0]);
	int facility = local_sysl_map[local];

	return _cfg_log_syslog(vty, facility);
}

static struct value_string sysl_level_names[] = {
	{ LOG_AUTHPRIV, "authpriv" },
	{ LOG_CRON, 	"cron" },
	{ LOG_DAEMON,	"daemon" },
	{ LOG_FTP,	"ftp" },
	{ LOG_LPR,	"lpr" },
	{ LOG_MAIL,	"mail" },
	{ LOG_NEWS,	"news" },
	{ LOG_USER,	"user" },
	{ LOG_UUCP,	"uucp" },
	/* only for value -> string conversion */
	{ LOG_LOCAL0,	"local 0" },
	{ LOG_LOCAL1,	"local 1" },
	{ LOG_LOCAL2,	"local 2" },
	{ LOG_LOCAL3,	"local 3" },
	{ LOG_LOCAL4,	"local 4" },
	{ LOG_LOCAL5,	"local 5" },
	{ LOG_LOCAL6,	"local 6" },
	{ LOG_LOCAL7,	"local 7" },
	{ 0, NULL }
};

DEFUN(cfg_log_syslog, cfg_log_syslog_cmd,
      "log syslog (authpriv|cron|daemon|ftp|lpr|mail|news|user|uucp)",
	LOG_STR "Logging via syslog\n"
	"Security/authorization messages facility\n"
	"Clock daemon (cron/at) facility\n"
	"General system daemon facility\n"
	"Ftp daemon facility\n"
	"Line printer facility\n"
	"Mail facility\n"
	"News facility\n"
	"Generic facility\n"
	"UUCP facility\n")
{
	int facility = get_string_value(sysl_level_names, argv[0]);

	return _cfg_log_syslog(vty, facility);
}

DEFUN(cfg_no_log_syslog, cfg_no_log_syslog_cmd,
	"no log syslog",
	NO_STR LOG_STR "Logging via syslog\n")
{
	struct log_target *tgt;

	tgt = log_target_find(LOG_TGT_TYPE_SYSLOG, NULL);
	if (!tgt) {
		vty_out(vty, "%% No syslog target found%s",
			VTY_NEWLINE);
		return CMD_WARNING;
	}

	log_target_destroy(tgt);

	return CMD_SUCCESS;
}
#endif /* HAVE_SYSLOG_H */

DEFUN(cfg_log_gsmtap, cfg_log_gsmtap_cmd,
	"log gsmtap [HOSTNAME]",
	LOG_STR "Logging via GSMTAP\n"
	"Host name to send the GSMTAP logging to (UDP port 4729)\n")
{
	const char *hostname = argc ? argv[0] : "127.0.0.1";
	struct log_target *tgt;

	tgt = log_target_find(LOG_TGT_TYPE_GSMTAP, hostname);
	if (!tgt) {
		tgt = log_target_create_gsmtap(hostname, GSMTAP_UDP_PORT,
					       host.app_info->name, false,
					       true);
		if (!tgt) {
			vty_out(vty, "%% Unable to create GSMTAP log for %s%s",
				hostname, VTY_NEWLINE);
			return CMD_WARNING;
		}
		log_add_target(tgt);
	}

	vty->index = tgt;
	vty->node = CFG_LOG_NODE;

	return CMD_SUCCESS;
}

DEFUN(cfg_log_stderr, cfg_log_stderr_cmd,
	"log stderr",
	LOG_STR "Logging via STDERR of the process\n")
{
	struct log_target *tgt;

	tgt = log_target_find(LOG_TGT_TYPE_STDERR, NULL);
	if (!tgt) {
		tgt = log_target_create_stderr();
		if (!tgt) {
			vty_out(vty, "%% Unable to create stderr log%s",
				VTY_NEWLINE);
			return CMD_WARNING;
		}
		log_add_target(tgt);
	}

	vty->index = tgt;
	vty->node = CFG_LOG_NODE;

	return CMD_SUCCESS;
}

DEFUN(cfg_no_log_stderr, cfg_no_log_stderr_cmd,
	"no log stderr",
	NO_STR LOG_STR "Logging via STDERR of the process\n")
{
	struct log_target *tgt;

	tgt = log_target_find(LOG_TGT_TYPE_STDERR, NULL);
	if (!tgt) {
		vty_out(vty, "%% No stderr logging active%s", VTY_NEWLINE);
		return CMD_WARNING;
	}

	log_target_destroy(tgt);

	return CMD_SUCCESS;
}

DEFUN(cfg_log_file, cfg_log_file_cmd,
	"log file .FILENAME",
	LOG_STR "Logging to text file\n" "Filename\n")
{
	const char *fname = argv[0];
	struct log_target *tgt;

	tgt = log_target_find(LOG_TGT_TYPE_FILE, fname);
	if (!tgt) {
		tgt = log_target_create_file(fname);
		if (!tgt) {
			vty_out(vty, "%% Unable to create file `%s'%s",
				fname, VTY_NEWLINE);
			return CMD_WARNING;
		}
		log_add_target(tgt);
	}

	vty->index = tgt;
	vty->node = CFG_LOG_NODE;

	return CMD_SUCCESS;
}


DEFUN(cfg_no_log_file, cfg_no_log_file_cmd,
	"no log file .FILENAME",
	NO_STR LOG_STR "Logging to text file\n" "Filename\n")
{
	const char *fname = argv[0];
	struct log_target *tgt;

	tgt = log_target_find(LOG_TGT_TYPE_FILE, fname);
	if (!tgt) {
		vty_out(vty, "%% No such log file `%s'%s",
			fname, VTY_NEWLINE);
		return CMD_WARNING;
	}

	log_target_destroy(tgt);

	return CMD_SUCCESS;
}

DEFUN(cfg_log_alarms, cfg_log_alarms_cmd,
	"log alarms <2-32700>",
	LOG_STR "Logging alarms to osmo_strrb\n"
	"Maximum number of messages to log\n")
{
	struct log_target *tgt;
	unsigned int rbsize = atoi(argv[0]);

	tgt = log_target_find(LOG_TGT_TYPE_STRRB, NULL);
	if (tgt)
		log_target_destroy(tgt);

	tgt = log_target_create_rb(rbsize);
	if (!tgt) {
		vty_out(vty, "%% Unable to create osmo_strrb (size %u)%s",
			rbsize, VTY_NEWLINE);
		return CMD_WARNING;
	}
	log_add_target(tgt);

	vty->index = tgt;
	vty->node = CFG_LOG_NODE;

	return CMD_SUCCESS;
}

DEFUN(cfg_no_log_alarms, cfg_no_log_alarms_cmd,
	"no log alarms",
	NO_STR LOG_STR "Logging alarms to osmo_strrb\n")
{
	struct log_target *tgt;

	tgt = log_target_find(LOG_TGT_TYPE_STRRB, NULL);
	if (!tgt) {
		vty_out(vty, "%% No osmo_strrb target found%s", VTY_NEWLINE);
		return CMD_WARNING;
	}

	log_target_destroy(tgt);

	return CMD_SUCCESS;
}

static int config_write_log_single(struct vty *vty, struct log_target *tgt)
{
	int i;
	char level_lower[32];

	switch (tgt->type) {
	case LOG_TGT_TYPE_VTY:
		return 1;
		break;
	case LOG_TGT_TYPE_STDERR:
		vty_out(vty, "log stderr%s", VTY_NEWLINE);
		break;
	case LOG_TGT_TYPE_SYSLOG:
#ifdef HAVE_SYSLOG_H
		vty_out(vty, "log syslog %s%s",
			get_value_string(sysl_level_names,
					 tgt->tgt_syslog.facility),
			VTY_NEWLINE);
#endif
		break;
	case LOG_TGT_TYPE_FILE:
		vty_out(vty, "log file %s%s", tgt->tgt_file.fname, VTY_NEWLINE);
		break;
	case LOG_TGT_TYPE_STRRB:
		vty_out(vty, "log alarms %zu%s",
			log_target_rb_avail_size(tgt), VTY_NEWLINE);
		break;
	case LOG_TGT_TYPE_GSMTAP:
		vty_out(vty, "log gsmtap %s%s",
			tgt->tgt_gsmtap.hostname, VTY_NEWLINE);
		break;
	}

	vty_out(vty, "  logging filter all %u%s",
		tgt->filter_map & (1 << LOG_FLT_ALL) ? 1 : 0, VTY_NEWLINE);
	/* save filters outside of libosmocore, i.e. in app code */
	if (osmo_log_info->save_fn)
		osmo_log_info->save_fn(vty, osmo_log_info, tgt);

	vty_out(vty, "  logging color %u%s", tgt->use_color ? 1 : 0,
		VTY_NEWLINE);
	vty_out(vty, "  logging print category %d%s",
		tgt->print_category ? 1 : 0, VTY_NEWLINE);
	if (tgt->print_ext_timestamp)
		vty_out(vty, "  logging print extended-timestamp 1%s", VTY_NEWLINE);
	else
		vty_out(vty, "  logging timestamp %u%s",
			tgt->print_timestamp ? 1 : 0, VTY_NEWLINE);
	if (tgt->print_level)
		vty_out(vty, "  logging print level 1%s", VTY_NEWLINE);
	vty_out(vty, "  logging print file %s%s",
		get_value_string(logging_print_file_args, tgt->print_filename2),
		VTY_NEWLINE);

	/* stupid old osmo logging API uses uppercase strings... */
	osmo_str2lower(level_lower, log_level_str(tgt->loglevel));
	vty_out(vty, "  logging level all %s%s", level_lower, VTY_NEWLINE);

	for (i = 0; i < osmo_log_info->num_cat; i++) {
		const struct log_category *cat = &tgt->categories[i];
		char cat_lower[32];

		/* skip empty entries in the array */
		if (!osmo_log_info->cat[i].name)
			continue;

		/* stupid old osmo logging API uses uppercase strings... */
		osmo_str2lower(cat_lower, osmo_log_info->cat[i].name+1);
		osmo_str2lower(level_lower, log_level_str(cat->loglevel));

		if (strcmp(level_lower, "everything") != 0) /* FIXME: remove this check once 'everything' is phased out */
			vty_out(vty, "  logging level %s %s%s", cat_lower, level_lower, VTY_NEWLINE);
		else
			LOGP(DLSTATS, LOGL_ERROR, "logging level everything is deprecated and should not be used\n");
	}

	/* FIXME: levels */

	return 1;
}

static int config_write_log(struct vty *vty)
{
	struct log_target *dbg = vty->index;

	llist_for_each_entry(dbg, &osmo_log_target_list, entry)
		config_write_log_single(vty, dbg);

	return 1;
}

/*! Register logging related commands to the VTY. Call this once from
 *  your application if you want to support those commands. */
void logging_vty_add_cmds()
{
	install_element_ve(&enable_logging_cmd);
	install_element_ve(&disable_logging_cmd);
	install_element_ve(&logging_fltr_all_cmd);
	install_element_ve(&logging_use_clr_cmd);
	install_element_ve(&logging_prnt_timestamp_cmd);
	install_element_ve(&logging_prnt_ext_timestamp_cmd);
	install_element_ve(&logging_prnt_cat_cmd);
	install_element_ve(&logging_prnt_cat_hex_cmd);
	install_element_ve(&logging_prnt_level_cmd);
	install_element_ve(&logging_prnt_file_cmd);
	install_element_ve(&logging_set_category_mask_cmd);
	install_element_ve(&logging_set_category_mask_old_cmd);

	/* Logging level strings are generated dynamically. */
	logging_level_cmd.string = log_vty_command_string();
	logging_level_cmd.doc = log_vty_command_description();
	install_element_ve(&logging_level_cmd);
	install_element_ve(&show_logging_vty_cmd);
	install_element_ve(&show_alarms_cmd);

	install_node(&cfg_log_node, config_write_log);
	install_element(CFG_LOG_NODE, &logging_fltr_all_cmd);
	install_element(CFG_LOG_NODE, &logging_use_clr_cmd);
	install_element(CFG_LOG_NODE, &logging_prnt_timestamp_cmd);
	install_element(CFG_LOG_NODE, &logging_prnt_ext_timestamp_cmd);
	install_element(CFG_LOG_NODE, &logging_prnt_cat_cmd);
	install_element(CFG_LOG_NODE, &logging_prnt_cat_hex_cmd);
	install_element(CFG_LOG_NODE, &logging_prnt_level_cmd);
	install_element(CFG_LOG_NODE, &logging_prnt_file_cmd);
	install_element(CFG_LOG_NODE, &logging_level_cmd);

	install_element(CONFIG_NODE, &cfg_log_stderr_cmd);
	install_element(CONFIG_NODE, &cfg_no_log_stderr_cmd);
	install_element(CONFIG_NODE, &cfg_log_file_cmd);
	install_element(CONFIG_NODE, &cfg_no_log_file_cmd);
	install_element(CONFIG_NODE, &cfg_log_alarms_cmd);
	install_element(CONFIG_NODE, &cfg_no_log_alarms_cmd);
#ifdef HAVE_SYSLOG_H
	install_element(CONFIG_NODE, &cfg_log_syslog_cmd);
	install_element(CONFIG_NODE, &cfg_log_syslog_local_cmd);
	install_element(CONFIG_NODE, &cfg_no_log_syslog_cmd);
#endif
	install_element(CONFIG_NODE, &cfg_log_gsmtap_cmd);
}