commit f412eed9dfdeeb6becd7de2ffe8b5d0a8b3f81ca
author Jakub Kicinski <jakub.kicinski@netronome.com> Thu May 03 18:37:16 2018 -0700
committer Daniel Borkmann <daniel@iogearbox.net> Fri May 04 23:41:04 2018 +0200
tree c6cf7b305e343a73505d5d1d25ee300a46992147
parent e64d52569f6e847495091db40ab58d2d379748ef

tools: bpftool: add simple perf event output reader

Users of BPF sooner or later discover perf_event_output() helpers
and BPF_MAP_TYPE_PERF_EVENT_ARRAY.  Dumping this array type is
not possible, however, we can add simple reading of perf events.
Create a new event_pipe subcommand for maps, this sub command
will only work with BPF_MAP_TYPE_PERF_EVENT_ARRAY maps.

Parts of the code from samples/bpf/trace_output_user.c.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/bpf/bpftool/map.c

diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 5efefde..af6766e 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -130,8 +130,7 @@ static int map_parse_fd(int *argc, char ***argv)
 	return -1;
 }
 
-static int
-map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len)
+int map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len)
 {
 	int err;
 	int fd;
@@ -817,12 +816,13 @@ static int do_help(int argc, char **argv)
 
 	fprintf(stderr,
 		"Usage: %s %s { show | list }   [MAP]\n"
-		"       %s %s dump    MAP\n"
-		"       %s %s update  MAP  key DATA value VALUE [UPDATE_FLAGS]\n"
-		"       %s %s lookup  MAP  key DATA\n"
-		"       %s %s getnext MAP [key DATA]\n"
-		"       %s %s delete  MAP  key DATA\n"
-		"       %s %s pin     MAP  FILE\n"
+		"       %s %s dump       MAP\n"
+		"       %s %s update     MAP  key DATA value VALUE [UPDATE_FLAGS]\n"
+		"       %s %s lookup     MAP  key DATA\n"
+		"       %s %s getnext    MAP [key DATA]\n"
+		"       %s %s delete     MAP  key DATA\n"
+		"       %s %s pin        MAP  FILE\n"
+		"       %s %s event_pipe MAP [cpu N index M]\n"
 		"       %s %s help\n"
 		"\n"
 		"       MAP := { id MAP_ID | pinned FILE }\n"
@@ -834,7 +834,7 @@ static int do_help(int argc, char **argv)
 		"",
 		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
 		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
-		bin_name, argv[-2], bin_name, argv[-2]);
+		bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2]);
 
 	return 0;
 }
@@ -849,6 +849,7 @@ static const struct cmd cmds[] = {
 	{ "getnext",	do_getnext },
 	{ "delete",	do_delete },
 	{ "pin",	do_pin },
+	{ "event_pipe",	do_event_pipe },
 	{ 0 }
 };