From: Philippe Proulx <eeppeliteloop@gmail.com>
Date: Tue, 17 Nov 2015 06:20:34 +0000 (-0500)
Subject: lttng: show man page when using command's --help
X-Git-Tag: v2.8.0-rc1~31
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=4ba92f185fb1d0b112cbc804a261939f5f81dc34;p=lttng-tools.git

lttng: show man page when using command's --help

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

diff --git a/src/bin/lttng/command.h b/src/bin/lttng/command.h
index 451e30f79..05c51663b 100644
--- a/src/bin/lttng/command.h
+++ b/src/bin/lttng/command.h
@@ -28,6 +28,16 @@
 #define DECL_COMMAND(_name) \
 	extern int cmd_##_name(int, const char **)
 
+#define SHOW_HELP() 							\
+	do {								\
+		ret = show_cmd_man_page(argv[0]);			\
+									\
+		if (ret) {						\
+			ERR("Cannot view man page lttng-%s(1)", argv[0]); \
+			perror("exec");					\
+		}							\
+	} while (0)
+
 enum cmd_error_code {
 	CMD_SUCCESS = 0,
 	CMD_ERROR,
diff --git a/src/bin/lttng/commands/add_context.c b/src/bin/lttng/commands/add_context.c
index 6f7c23c01..56ee2aca4 100644
--- a/src/bin/lttng/commands/add_context.c
+++ b/src/bin/lttng/commands/add_context.c
@@ -841,7 +841,7 @@ int cmd_add_context(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_LIST:
 			print_ctx_type(stdout);
diff --git a/src/bin/lttng/commands/calibrate.c b/src/bin/lttng/commands/calibrate.c
index b15ce40cf..ba3350fb6 100644
--- a/src/bin/lttng/commands/calibrate.c
+++ b/src/bin/lttng/commands/calibrate.c
@@ -172,7 +172,7 @@ int cmd_calibrate(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_TRACEPOINT:
 			ret = CMD_UNDEFINED;
diff --git a/src/bin/lttng/commands/create.c b/src/bin/lttng/commands/create.c
index 5027fce90..efc9e60c1 100644
--- a/src/bin/lttng/commands/create.c
+++ b/src/bin/lttng/commands/create.c
@@ -699,7 +699,7 @@ int cmd_create(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_LIST_OPTIONS:
 			list_cmd_options(stdout, long_options);
diff --git a/src/bin/lttng/commands/destroy.c b/src/bin/lttng/commands/destroy.c
index ad181d7c4..661c0a235 100644
--- a/src/bin/lttng/commands/destroy.c
+++ b/src/bin/lttng/commands/destroy.c
@@ -189,7 +189,7 @@ int cmd_destroy(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			break;
 		case OPT_LIST_OPTIONS:
 			list_cmd_options(stdout, long_options);
diff --git a/src/bin/lttng/commands/disable_channels.c b/src/bin/lttng/commands/disable_channels.c
index f1f2e51b9..a8bfa5dea 100644
--- a/src/bin/lttng/commands/disable_channels.c
+++ b/src/bin/lttng/commands/disable_channels.c
@@ -233,7 +233,7 @@ int cmd_disable_channels(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_USERSPACE:
 			opt_userspace = 1;
diff --git a/src/bin/lttng/commands/disable_events.c b/src/bin/lttng/commands/disable_events.c
index cc2711565..b853c57f7 100644
--- a/src/bin/lttng/commands/disable_events.c
+++ b/src/bin/lttng/commands/disable_events.c
@@ -361,7 +361,7 @@ int cmd_disable_events(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_TYPE_SYSCALL:
 			opt_event_type = LTTNG_EVENT_SYSCALL;
diff --git a/src/bin/lttng/commands/enable_channels.c b/src/bin/lttng/commands/enable_channels.c
index 696b8e094..93d81d735 100644
--- a/src/bin/lttng/commands/enable_channels.c
+++ b/src/bin/lttng/commands/enable_channels.c
@@ -401,7 +401,7 @@ int cmd_enable_channels(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_DISCARD:
 			chan.attr.overwrite = 0;
diff --git a/src/bin/lttng/commands/enable_events.c b/src/bin/lttng/commands/enable_events.c
index 6a5369766..2c366c6d2 100644
--- a/src/bin/lttng/commands/enable_events.c
+++ b/src/bin/lttng/commands/enable_events.c
@@ -1401,7 +1401,7 @@ int cmd_enable_events(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_TRACEPOINT:
 			opt_event_type = LTTNG_EVENT_TRACEPOINT;
diff --git a/src/bin/lttng/commands/list.c b/src/bin/lttng/commands/list.c
index b122b5b78..7a35258b4 100644
--- a/src/bin/lttng/commands/list.c
+++ b/src/bin/lttng/commands/list.c
@@ -1737,7 +1737,7 @@ int cmd_list(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_USERSPACE:
 			opt_userspace = 1;
diff --git a/src/bin/lttng/commands/load.c b/src/bin/lttng/commands/load.c
index cb3eb75aa..7a29da52d 100644
--- a/src/bin/lttng/commands/load.c
+++ b/src/bin/lttng/commands/load.c
@@ -151,7 +151,7 @@ int cmd_load(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_ALL:
 			opt_load_all = 1;
diff --git a/src/bin/lttng/commands/save.c b/src/bin/lttng/commands/save.c
index 6bd873226..66ec5b6eb 100644
--- a/src/bin/lttng/commands/save.c
+++ b/src/bin/lttng/commands/save.c
@@ -146,7 +146,7 @@ int cmd_save(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_ALL:
 			opt_save_all = 1;
diff --git a/src/bin/lttng/commands/set_session.c b/src/bin/lttng/commands/set_session.c
index c0572e127..d41dc1d19 100644
--- a/src/bin/lttng/commands/set_session.c
+++ b/src/bin/lttng/commands/set_session.c
@@ -174,7 +174,7 @@ int cmd_set_session(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_LIST_OPTIONS:
 			list_cmd_options(stdout, long_options);
diff --git a/src/bin/lttng/commands/snapshot.c b/src/bin/lttng/commands/snapshot.c
index 465d864de..1d7843954 100644
--- a/src/bin/lttng/commands/snapshot.c
+++ b/src/bin/lttng/commands/snapshot.c
@@ -715,7 +715,7 @@ int cmd_snapshot(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_LIST_OPTIONS:
 			list_cmd_options(stdout, snapshot_opts);
diff --git a/src/bin/lttng/commands/start.c b/src/bin/lttng/commands/start.c
index b353eb6e3..90794c669 100644
--- a/src/bin/lttng/commands/start.c
+++ b/src/bin/lttng/commands/start.c
@@ -161,7 +161,7 @@ int cmd_start(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_LIST_OPTIONS:
 			list_cmd_options(stdout, long_options);
diff --git a/src/bin/lttng/commands/status.c b/src/bin/lttng/commands/status.c
index d9b6c4f27..693527535 100644
--- a/src/bin/lttng/commands/status.c
+++ b/src/bin/lttng/commands/status.c
@@ -83,7 +83,7 @@ int cmd_status(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_LIST_OPTIONS:
 			list_cmd_options(stdout, long_options);
diff --git a/src/bin/lttng/commands/stop.c b/src/bin/lttng/commands/stop.c
index b3fff0753..e946d4fdb 100644
--- a/src/bin/lttng/commands/stop.c
+++ b/src/bin/lttng/commands/stop.c
@@ -189,7 +189,7 @@ int cmd_stop(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_LIST_OPTIONS:
 			list_cmd_options(stdout, long_options);
diff --git a/src/bin/lttng/commands/track-untrack.c b/src/bin/lttng/commands/track-untrack.c
index a4f4689e7..6d8d91ffd 100644
--- a/src/bin/lttng/commands/track-untrack.c
+++ b/src/bin/lttng/commands/track-untrack.c
@@ -364,7 +364,7 @@ int cmd_track_untrack(enum cmd_type cmd_type, const char *cmd_str,
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout, cmd_str);
+			SHOW_HELP();
 			goto end;
 		case OPT_LIST_OPTIONS:
 			list_cmd_options(stdout, long_options);
diff --git a/src/bin/lttng/commands/version.c b/src/bin/lttng/commands/version.c
index 7634f5871..3630950bb 100644
--- a/src/bin/lttng/commands/version.c
+++ b/src/bin/lttng/commands/version.c
@@ -148,7 +148,7 @@ int cmd_version(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_LIST_OPTIONS:
 			list_cmd_options(stdout, long_options);
diff --git a/src/bin/lttng/commands/view.c b/src/bin/lttng/commands/view.c
index 44e0cb015..dac2c3e24 100644
--- a/src/bin/lttng/commands/view.c
+++ b/src/bin/lttng/commands/view.c
@@ -444,7 +444,7 @@ int cmd_view(int argc, const char **argv)
 	while ((opt = poptGetNextOpt(pc)) != -1) {
 		switch (opt) {
 		case OPT_HELP:
-			usage(stdout);
+			SHOW_HELP();
 			goto end;
 		case OPT_LIST_OPTIONS:
 			list_cmd_options(stdout, long_options);
diff --git a/src/bin/lttng/utils.c b/src/bin/lttng/utils.c
index 802e0971b..912cbd577 100644
--- a/src/bin/lttng/utils.c
+++ b/src/bin/lttng/utils.c
@@ -26,9 +26,11 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <inttypes.h>
+#include <unistd.h>
 
 #include <common/error.h>
 #include <common/utils.h>
+#include <common/defaults.h>
 
 #include "conf.h"
 #include "utils.h"
@@ -479,3 +481,14 @@ void print_session_stats(const char *session_name)
 end:
 	return;
 }
+
+int show_cmd_man_page(const char *cmd_name)
+{
+	int ret;
+	char page_name[32];
+
+	ret = sprintf(page_name, "lttng-%s", cmd_name);
+	assert(ret > 0 && ret < 32);
+
+	return utils_show_man_page(1, page_name);
+}
diff --git a/src/bin/lttng/utils.h b/src/bin/lttng/utils.h
index 0d70cf751..7f656df13 100644
--- a/src/bin/lttng/utils.h
+++ b/src/bin/lttng/utils.h
@@ -60,5 +60,6 @@ int print_missing_or_multiple_domains(unsigned int sum);
 int spawn_relayd(const char *pathname, int port);
 int check_relayd(void);
 void print_session_stats(const char *session_name);
+int show_cmd_man_page(const char *cmd_name);
 
 #endif /* _LTTNG_UTILS_H */
diff --git a/src/common/Makefile.am b/src/common/Makefile.am
index c1b9d4e7a..5096676e0 100644
--- a/src/common/Makefile.am
+++ b/src/common/Makefile.am
@@ -1,4 +1,5 @@
-AM_CPPFLAGS = -I$(top_srcdir)/include -I$(top_srcdir)/src
+AM_CPPFLAGS = -I$(top_srcdir)/include -I$(top_srcdir)/src \
+	-DMANPATH=\""$(mandir)"\"
 
 AUTOMAKE_OPTIONS = subdir-objects
 
diff --git a/src/common/defaults.h b/src/common/defaults.h
index f45c8f6f0..6e343b50c 100644
--- a/src/common/defaults.h
+++ b/src/common/defaults.h
@@ -35,6 +35,12 @@
 /* Environment variable to set session daemon binary path. */
 #define DEFAULT_SESSIOND_PATH_ENV               "LTTNG_SESSIOND_PATH"
 
+/* Environment variable to set man pager binary path. */
+#define DEFAULT_MAN_BIN_PATH_ENV                "LTTNG_MAN_BIN_PATH"
+
+/* Default man pager binary path. */
+#define DEFAULT_MAN_BIN_PATH                    "/usr/bin/man"
+
 /* Default trace output directory name */
 #define DEFAULT_TRACE_DIR_NAME                  "lttng-traces"
 
diff --git a/src/common/utils.c b/src/common/utils.c
index d71d92446..df55dc9fb 100644
--- a/src/common/utils.c
+++ b/src/common/utils.c
@@ -1341,7 +1341,40 @@ int utils_truncate_stream_file(int fd, off_t length)
 		PERROR("lseek");
 		goto end;
 	}
-
 end:
 	return ret;
 }
+
+static const char *get_man_bin_path(void)
+{
+	char *env_man_path = getenv(DEFAULT_MAN_BIN_PATH_ENV);
+
+	if (env_man_path) {
+		return env_man_path;
+	}
+
+	return DEFAULT_MAN_BIN_PATH;
+}
+
+LTTNG_HIDDEN
+int utils_show_man_page(int section, const char *page_name)
+{
+	char section_string[8];
+	const char *man_bin_path = get_man_bin_path();
+	int ret;
+
+	/* Section integer -> section string */
+	ret = sprintf(section_string, "%d", section);
+	assert(ret > 0 && ret < 8);
+
+	/*
+	 * Execute man pager.
+	 *
+	 * We provide --manpath to man here because LTTng-tools can
+	 * be installed outside /usr, in which case its man pages are
+	 * not located in the default /usr/share/man directory.
+	 */
+	ret = execlp(man_bin_path, "man", "--manpath", MANPATH,
+		section_string, page_name, NULL);
+	return ret;
+}
diff --git a/src/common/utils.h b/src/common/utils.h
index 5272d54a6..7285f5c30 100644
--- a/src/common/utils.h
+++ b/src/common/utils.h
@@ -59,5 +59,6 @@ char *utils_generate_optstring(const struct option *long_options,
 int utils_create_lock_file(const char *filepath);
 int utils_recursive_rmdir(const char *path);
 int utils_truncate_stream_file(int fd, off_t length);
+int utils_show_man_page(int section, const char *page_name);
 
 #endif /* _COMMON_UTILS_H */