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tools: bpftool: add simple perf event output reader
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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>
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Jakub Kicinski authored and Daniel Borkmann committed May 4, 2018
1 parent e64d525 commit f412eed
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29 changes: 23 additions & 6 deletions tools/bpf/bpftool/Documentation/bpftool-map.rst
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Expand Up @@ -22,12 +22,13 @@ MAP COMMANDS
=============

| **bpftool** **map { show | list }** [*MAP*]
| **bpftool** **map dump** *MAP*
| **bpftool** **map update** *MAP* **key** *DATA* **value** *VALUE* [*UPDATE_FLAGS*]
| **bpftool** **map lookup** *MAP* **key** *DATA*
| **bpftool** **map getnext** *MAP* [**key** *DATA*]
| **bpftool** **map delete** *MAP* **key** *DATA*
| **bpftool** **map pin** *MAP* *FILE*
| **bpftool** **map dump** *MAP*
| **bpftool** **map update** *MAP* **key** *DATA* **value** *VALUE* [*UPDATE_FLAGS*]
| **bpftool** **map lookup** *MAP* **key** *DATA*
| **bpftool** **map getnext** *MAP* [**key** *DATA*]
| **bpftool** **map delete** *MAP* **key** *DATA*
| **bpftool** **map pin** *MAP* *FILE*
| **bpftool** **map event_pipe** *MAP* [**cpu** *N* **index** *M*]
| **bpftool** **map help**
|
| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
Expand Down Expand Up @@ -76,6 +77,22 @@ DESCRIPTION

Note: *FILE* must be located in *bpffs* mount.

**bpftool** **map event_pipe** *MAP* [**cpu** *N* **index** *M*]
Read events from a BPF_MAP_TYPE_PERF_EVENT_ARRAY map.

Install perf rings into a perf event array map and dump
output of any bpf_perf_event_output() call in the kernel.
By default read the number of CPUs on the system and
install perf ring for each CPU in the corresponding index
in the array.

If **cpu** and **index** are specified, install perf ring
for given **cpu** at **index** in the array (single ring).

Note that installing a perf ring into an array will silently
replace any existing ring. Any other application will stop
receiving events if it installed its rings earlier.

**bpftool map help**
Print short help message.

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2 changes: 1 addition & 1 deletion tools/bpf/bpftool/Documentation/bpftool.rst
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Expand Up @@ -23,7 +23,7 @@ SYNOPSIS
*MAP-COMMANDS* :=
{ **show** | **list** | **dump** | **update** | **lookup** | **getnext** | **delete**
| **pin** | **help** }
| **pin** | **event_pipe** | **help** }
*PROG-COMMANDS* := { **show** | **list** | **dump jited** | **dump xlated** | **pin**
| **load** | **help** }
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7 changes: 6 additions & 1 deletion tools/bpf/bpftool/Makefile
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Expand Up @@ -39,7 +39,12 @@ CC = gcc

CFLAGS += -O2
CFLAGS += -W -Wall -Wextra -Wno-unused-parameter -Wshadow -Wno-missing-field-initializers
CFLAGS += -DPACKAGE='"bpftool"' -D__EXPORTED_HEADERS__ -I$(srctree)/tools/include/uapi -I$(srctree)/tools/include -I$(srctree)/tools/lib/bpf -I$(srctree)/kernel/bpf/
CFLAGS += -DPACKAGE='"bpftool"' -D__EXPORTED_HEADERS__ \
-I$(srctree)/kernel/bpf/ \
-I$(srctree)/tools/include \
-I$(srctree)/tools/include/uapi \
-I$(srctree)/tools/lib/bpf \
-I$(srctree)/tools/perf
CFLAGS += -DBPFTOOL_VERSION='"$(BPFTOOL_VERSION)"'
LIBS = -lelf -lbfd -lopcodes $(LIBBPF)

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36 changes: 34 additions & 2 deletions tools/bpf/bpftool/bash-completion/bpftool
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@@ -1,6 +1,6 @@
# bpftool(8) bash completion -*- shell-script -*-
#
# Copyright (C) 2017 Netronome Systems, Inc.
# Copyright (C) 2017-2018 Netronome Systems, Inc.
#
# This software is dual licensed under the GNU General License
# Version 2, June 1991 as shown in the file COPYING in the top-level
Expand Down Expand Up @@ -79,6 +79,14 @@ _bpftool_get_map_ids()
command sed -n 's/.*"id": \(.*\),$/\1/p' )" -- "$cur" ) )
}

_bpftool_get_perf_map_ids()
{
COMPREPLY+=( $( compgen -W "$( bpftool -jp map 2>&1 | \
command grep -C2 perf_event_array | \
command sed -n 's/.*"id": \(.*\),$/\1/p' )" -- "$cur" ) )
}


_bpftool_get_prog_ids()
{
COMPREPLY+=( $( compgen -W "$( bpftool -jp prog 2>&1 | \
Expand Down Expand Up @@ -359,10 +367,34 @@ _bpftool()
fi
return 0
;;
event_pipe)
case $prev in
$command)
COMPREPLY=( $( compgen -W "$MAP_TYPE" -- "$cur" ) )
return 0
;;
id)
_bpftool_get_perf_map_ids
return 0
;;
cpu)
return 0
;;
index)
return 0
;;
*)
_bpftool_once_attr 'cpu'
_bpftool_once_attr 'index'
return 0
;;
esac
;;
*)
[[ $prev == $object ]] && \
COMPREPLY=( $( compgen -W 'delete dump getnext help \
lookup pin show list update' -- "$cur" ) )
lookup pin event_pipe show list update' -- \
"$cur" ) )
;;
esac
;;
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19 changes: 19 additions & 0 deletions tools/bpf/bpftool/common.c
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Expand Up @@ -331,6 +331,16 @@ char *get_fdinfo(int fd, const char *key)
return NULL;
}

void print_data_json(uint8_t *data, size_t len)
{
unsigned int i;

jsonw_start_array(json_wtr);
for (i = 0; i < len; i++)
jsonw_printf(json_wtr, "%d", data[i]);
jsonw_end_array(json_wtr);
}

void print_hex_data_json(uint8_t *data, size_t len)
{
unsigned int i;
Expand Down Expand Up @@ -421,6 +431,15 @@ void delete_pinned_obj_table(struct pinned_obj_table *tab)
}
}

unsigned int get_page_size(void)
{
static int result;

if (!result)
result = getpagesize();
return result;
}

unsigned int get_possible_cpus(void)
{
static unsigned int result;
Expand Down
4 changes: 4 additions & 0 deletions tools/bpf/bpftool/main.h
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Expand Up @@ -117,14 +117,18 @@ int do_pin_fd(int fd, const char *name);

int do_prog(int argc, char **arg);
int do_map(int argc, char **arg);
int do_event_pipe(int argc, char **argv);
int do_cgroup(int argc, char **arg);

int prog_parse_fd(int *argc, char ***argv);
int map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len);

void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
const char *arch);
void print_data_json(uint8_t *data, size_t len);
void print_hex_data_json(uint8_t *data, size_t len);

unsigned int get_page_size(void);
unsigned int get_possible_cpus(void);
const char *ifindex_to_bfd_name_ns(__u32 ifindex, __u64 ns_dev, __u64 ns_ino);

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19 changes: 10 additions & 9 deletions tools/bpf/bpftool/map.c
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Expand Up @@ -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;
Expand Down Expand Up @@ -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"
Expand All @@ -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;
}
Expand All @@ -849,6 +849,7 @@ static const struct cmd cmds[] = {
{ "getnext", do_getnext },
{ "delete", do_delete },
{ "pin", do_pin },
{ "event_pipe", do_event_pipe },
{ 0 }
};

Expand Down
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