From: Philippe Proulx <eeppeliteloop@gmail.com>
Date: Tue, 17 Nov 2015 06:59:11 +0000 (-0500)
Subject: lttng: add `help` command
X-Git-Tag: v2.8.0-rc1~27
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=960afba4f737174cd305af2019d9c2c781ec6c4e;p=lttng-tools.git

lttng: add `help` command

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/src/bin/lttng/Makefile.am b/src/bin/lttng/Makefile.am
index 93a563ff5..b911f334c 100644
--- a/src/bin/lttng/Makefile.am
+++ b/src/bin/lttng/Makefile.am
@@ -18,6 +18,7 @@ lttng_SOURCES = command.h conf.c conf.h commands/start.c \
 				commands/track-untrack.c \
 				commands/status.c \
 				commands/metadata.c \
+				commands/help.c \
 				utils.c utils.h lttng.c
 
 lttng_LDADD = $(top_builddir)/src/lib/lttng-ctl/liblttng-ctl.la \
diff --git a/src/bin/lttng/command.h b/src/bin/lttng/command.h
index 05c51663b..72cf4e0ff 100644
--- a/src/bin/lttng/command.h
+++ b/src/bin/lttng/command.h
@@ -35,6 +35,7 @@
 		if (ret) {						\
 			ERR("Cannot view man page lttng-%s(1)", argv[0]); \
 			perror("exec");					\
+			ret = CMD_ERROR;				\
 		}							\
 	} while (0)
 
@@ -76,4 +77,7 @@ DECL_COMMAND(track);
 DECL_COMMAND(untrack);
 DECL_COMMAND(metadata);
 
+extern int cmd_help(int argc, const char **argv,
+		const struct cmd_struct commands[]);
+
 #endif /* _LTTNG_CMD_H */
diff --git a/src/bin/lttng/commands/help.c b/src/bin/lttng/commands/help.c
new file mode 100644
index 000000000..29f56bab1
--- /dev/null
+++ b/src/bin/lttng/commands/help.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2015 - Philippe Proulx <pproulx@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#define _LGPL_SOURCE
+#include <popt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "../command.h"
+#include <common/utils.h>
+
+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;
+
+	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_man_page(1, "lttng");
+
+		if (ret) {
+			ERR("Cannot view man page lttng(1)");
+			perror("exec");
+			ret = CMD_ERROR;
+			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 man page */
+	ret = show_cmd_man_page(cmd_name);
+
+	if (ret) {
+		ERR("Cannot view man page lttng-%s(1)", cmd_name);
+		perror("exec");
+		ret = CMD_ERROR;
+	}
+
+end:
+	poptFreeContext(pc);
+	return ret;
+}
diff --git a/src/bin/lttng/lttng.c b/src/bin/lttng/lttng.c
index aa13bc45d..bcfbf88e6 100644
--- a/src/bin/lttng/lttng.c
+++ b/src/bin/lttng/lttng.c
@@ -86,6 +86,7 @@ static struct cmd_struct commands[] =  {
 	{ "track", cmd_track},
 	{ "untrack", cmd_untrack},
 	{ "metadata", cmd_metadata},
+	{ "help", NULL},
 	{ NULL, NULL}	/* Array closure */
 };
 
@@ -216,8 +217,14 @@ static int handle_command(int argc, char **argv)
 		goto end;
 	}
 
+	/* Special case for help command which needs the commands array */
+	if (strcmp(argv[0], "help") == 0) {
+		ret = cmd_help(argc, (const char**) argv, commands);
+		goto end;
+	}
+
 	cmd = &commands[i];
-	while (cmd->func != NULL) {
+	while (cmd->name != NULL) {
 		/* Find command */
 		if (strcmp(argv[0], cmd->name) == 0) {
 			ret = cmd->func(argc, (const char**) argv);