res_cliexec: Add dialplan exec CLI command.

Adds a CLI command similar to "dialplan eval function" except for
applications: "dialplan exec application", useful for quickly
testing certain application behavior directly from the CLI
without writing any dialplan.

ASTERISK-30062 #close

Change-Id: I42e9fa9b60746c21450d40f99a026d48d2486dde

doc/CHANGES-staging/res_cliexec.txt

+Subject: res_cliexec
+
+A new CLI command, dialplan exec application, has
+been added which allows dialplan applications to be
+executed at the CLI, useful for some quick testing
+without needing to write dialplan.

res/res_cliexec.c

+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2022, Naveen Albert
+ *
+ * Naveen Albert <asterisk@phreaknet.org>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*!
+ * \file
+ * \author Naveen Albert <asterisk@phreaknet.org>
+ *
+ * \brief Execute dialplan applications from the CLI
+ *
+ */
+
+/*** MODULEINFO
+	<defaultenabled>no</defaultenabled>
+	<support_level>extended</support_level>
+ ***/
+
+#include "asterisk.h"
+
+#include "asterisk/channel.h"
+#include "asterisk/pbx.h"
+#include "asterisk/module.h"
+#include "asterisk/cli.h"
+#include "asterisk/utils.h"
+#include "asterisk/frame.h"
+#include "asterisk/format_cache.h"
+
+static const struct ast_channel_tech mock_channel_tech = {
+};
+
+static int cli_chan = 0;
+
+/*! \brief CLI support for executing application */
+static char *handle_exec(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
+{
+	struct ast_channel *c = NULL;
+	RAII_VAR(struct ast_format_cap *, caps, NULL, ao2_cleanup);
+	char *app_name, *app_args;
+	int ret = 0;
+	struct ast_app *app;
+
+	switch (cmd) {
+	case CLI_INIT:
+		e->command = "dialplan exec application";
+		e->usage =
+			"Usage: dialplan exec application <appname> [<args>]\n"
+			"       Execute a single dialplan application call for\n"
+			"       testing. A mock channel is used to execute\n"
+			"       the application, so it may not make\n"
+			"       sense to use all applications, and only\n"
+			"       global variables should be used.\n"
+			"       The ulaw, alaw, and h264 codecs are available.\n";
+		return NULL;
+	case CLI_GENERATE:
+		return NULL;
+	}
+
+	if (a->argc != e->args + 1 && a->argc != e->args + 2) {
+		return CLI_SHOWUSAGE;
+	}
+
+	app_name = (char *) a->argv[3];
+	app_args = a->argc == e->args + 2 ? (char *) a->argv[4] : NULL;
+
+	if (!app_name) {
+		return CLI_FAILURE;
+	}
+
+	caps = ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT);
+	if (!caps) {
+		ast_log(LOG_WARNING, "Could not allocate an empty format capabilities structure\n");
+		return CLI_FAILURE;
+	}
+
+	if (ast_format_cap_append(caps, ast_format_ulaw, 0)) {
+		ast_log(LOG_WARNING, "Failed to append a ulaw format to capabilities for channel nativeformats\n");
+		return CLI_FAILURE;
+	}
+
+	if (ast_format_cap_append(caps, ast_format_alaw, 0)) {
+		ast_log(LOG_WARNING, "Failed to append an alaw format to capabilities for channel nativeformats\n");
+		return CLI_FAILURE;
+	}
+
+	if (ast_format_cap_append(caps, ast_format_h264, 0)) {
+		ast_log(LOG_WARNING, "Failed to append an h264 format to capabilities for channel nativeformats\n");
+		return CLI_FAILURE;
+	}
+
+	c = ast_channel_alloc(0, AST_STATE_DOWN, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 0, "CLIExec/%d", ++cli_chan);
+	if (!c) {
+		ast_cli(a->fd, "Unable to allocate mock channel for application execution.\n");
+		return CLI_FAILURE;
+	}
+	ast_channel_tech_set(c, &mock_channel_tech);
+	ast_channel_nativeformats_set(c, caps);
+	ast_channel_set_writeformat(c, ast_format_slin);
+	ast_channel_set_rawwriteformat(c, ast_format_slin);
+	ast_channel_set_readformat(c, ast_format_slin);
+	ast_channel_set_rawreadformat(c, ast_format_slin);
+	ast_channel_unlock(c);
+
+	app = pbx_findapp(app_name);
+	if (!app) {
+		ast_log(LOG_WARNING, "Could not find application (%s)\n", app_name);
+		ast_hangup(c);
+		return CLI_FAILURE;
+	} else {
+		struct ast_str *substituted_args = ast_str_create(16);
+
+		if (substituted_args) {
+			ast_str_substitute_variables(&substituted_args, 0, c, app_args);
+			ast_cli(a->fd, "Executing: %s(%s)\n", app_name, ast_str_buffer(substituted_args));
+			ret = pbx_exec(c, app, ast_str_buffer(substituted_args));
+			ast_free(substituted_args);
+		} else {
+			ast_log(LOG_WARNING, "Could not substitute application argument variables for %s\n", app_name);
+			ast_cli(a->fd, "Executing: %s(%s)\n", app_name, app_args);
+			ret = pbx_exec(c, app, app_args);
+		}
+	}
+
+	ast_hangup(c); /* no need to unref separately */
+
+	ast_cli(a->fd, "Return Value: %s (%d)\n", ret ? "Failure" : "Success", ret);
+
+	return CLI_SUCCESS;
+}
+
+static struct ast_cli_entry cli_cliorig[] = {
+	AST_CLI_DEFINE(handle_exec, "Execute a dialplan application"),
+};
+
+static int unload_module(void)
+{
+	return ast_cli_unregister_multiple(cli_cliorig, ARRAY_LEN(cli_cliorig));
+}
+
+static int load_module(void)
+{
+	int res;
+	res = ast_cli_register_multiple(cli_cliorig, ARRAY_LEN(cli_cliorig));
+	return res ? AST_MODULE_LOAD_DECLINE : AST_MODULE_LOAD_SUCCESS;
+}
+
+AST_MODULE_INFO_STANDARD_EXTENDED(ASTERISK_GPL_KEY, "Simple dialplan execution from the CLI");