--- /dev/null
+/*
+ * Copyright (C) 2015 Philippe Proulx <pproulx@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#define _LGPL_SOURCE
+#include <popt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "../command.h"
+#include <common/utils.h>
+
+#ifdef LTTNG_EMBED_HELP
+static const char *help_msg =
+#include <lttng-help.1.h>
+;
+#endif
+
+static const char *lttng_help_msg =
+#ifdef LTTNG_EMBED_HELP
+#include <lttng.1.h>
+#else
+NULL
+#endif
+;
+
+enum {
+ OPT_HELP = 1,
+ OPT_LIST_OPTIONS,
+};
+
+static struct poptOption long_options[] = {
+ /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
+ {"help", 'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
+ {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
+ {0, 0, 0, 0, 0, 0, 0}
+};
+
+/*
+ * cmd_help
+ */
+int cmd_help(int argc, const char **argv, const struct cmd_struct commands[])
+{
+ int opt, ret = CMD_SUCCESS;
+ char *cmd_name;
+ static poptContext pc;
+ const struct cmd_struct *cmd;
+ int found = 0;
+ const char *cmd_argv[2];
+
+ pc = poptGetContext(NULL, argc, argv, long_options, 0);
+ poptReadDefaultConfig(pc, 0);
+
+ while ((opt = poptGetNextOpt(pc)) != -1) {
+ switch (opt) {
+ case OPT_HELP:
+ SHOW_HELP();
+ goto end;
+ case OPT_LIST_OPTIONS:
+ list_cmd_options(stdout, long_options);
+ goto end;
+ default:
+ ret = CMD_UNDEFINED;
+ goto end;
+ }
+ }
+
+ /* Get command name */
+ cmd_name = (char *) poptGetArg(pc);
+
+ if (cmd_name == NULL) {
+ /* Fall back to lttng(1) */
+ ret = utils_show_help(1, "lttng", lttng_help_msg);
+ if (ret) {
+ ERR("Cannot show --help for `lttng`");
+ perror("exec");
+ ret = CMD_ERROR;
+ }
+
+ goto end;
+ }
+
+ /* Help about help? */
+ if (strcmp(cmd_name, "help") == 0) {
+ SHOW_HELP();
+ goto end;
+ }
+
+ /* Make sure command name exists */
+ cmd = &commands[0];
+
+ while (cmd->name != NULL) {
+ if (strcmp(cmd->name, cmd_name) == 0) {
+ found = 1;
+ break;
+ }
+
+ cmd++;
+ }
+
+ if (!found) {
+ ERR("Unknown command \"%s\"", cmd_name);
+ ret = CMD_ERROR;
+ goto end;
+ }
+
+ /* Show command's help */
+ cmd_argv[0] = cmd->name;
+ cmd_argv[1] = "--help";
+ LTTNG_ASSERT(cmd->func);
+ ret = cmd->func(2, cmd_argv);
+
+end:
+ poptFreeContext(pc);
+ return ret;
+}