tools/bpftool: Add bpftool support for bpf map element iterator (d8793aca) · Commits · 戴 / test

tools/bpf/bpftool/Documentation/bpftool-iter.rst

+16 −2

Original line number	Diff line number	Diff line
		@@ -17,14 +17,15 @@ SYNOPSIS
		ITER COMMANDS
		===================

		\| bpftool iter pin OBJ PATH
		\| bpftool iter pin OBJ PATH [map MAP]
		\| bpftool iter help
		\|
		\| OBJ := /a/file/of/bpf_iter_target.o
		\| MAP := { id MAP_ID \| pinned FILE }

		DESCRIPTION
		===========
		bpftool iter pin OBJ PATH
		bpftool iter pin OBJ PATH [map MAP]
		A bpf iterator combines a kernel iterating of
		particular kernel data (e.g., tasks, bpf_maps, etc.)
		and a bpf program called for each kernel data object
		@@ -37,6 +38,12 @@ DESCRIPTION
		character ('.'), which is reserved for future extensions
		of bpffs.

		Map element bpf iterator requires an additional parameter
		MAP so bpf program can iterate over map elements for
		that map. User can have a bpf program in kernel to run
		with each map element, do checking, filtering, aggregation,
		etc. without copying data to user space.

		User can then cat PATH to see the bpf iterator output.

		bpftool iter help
		@@ -64,6 +71,13 @@ EXAMPLES
		Create a file-based bpf iterator from bpf_iter_netlink.o and pin it
		to /sys/fs/bpf/my_netlink

		# bpftool iter pin bpf_iter_hashmap.o /sys/fs/bpf/my_hashmap map id 20

		::

		Create a file-based bpf iterator from bpf_iter_hashmap.o and map with
		id 20, and pin it to /sys/fs/bpf/my_hashmap

		SEE ALSO
		========
		bpf\ (2),

tools/bpf/bpftool/bash-completion/bpftool

+17 −1

Original line number	Diff line number	Diff line
		@@ -615,7 +615,23 @@ _bpftool()
		iter)
		case $command in
		pin)
		case $prev in
		$command)
		_filedir
		;;
		id)
		_bpftool_get_map_ids
		;;
		name)
		_bpftool_get_map_names
		;;
		pinned)
		_filedir
		;;
		*)
		_bpftool_one_of_list $MAP_TYPE
		;;
		esac
		return 0
		;;
		*)

tools/bpf/bpftool/iter.c

+29 −4

Original line number	Diff line number	Diff line
		@@ -2,6 +2,7 @@
		// Copyright (C) 2020 Facebook

		#define _GNU_SOURCE
		#include <unistd.h>
		#include <linux/err.h>
		#include <bpf/libbpf.h>

		@@ -9,11 +10,12 @@

		static int do_pin(int argc, char **argv)
		{
		DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, iter_opts);
		const char objfile, path;
		struct bpf_program *prog;
		struct bpf_object *obj;
		struct bpf_link *link;
		int err;
		int err = -1, map_fd = -1;

		if (!REQ_ARGS(2))
		usage();
		@@ -21,10 +23,26 @@ static int do_pin(int argc, char **argv)
		objfile = GET_ARG();
		path = GET_ARG();

		/* optional arguments */
		if (argc) {
		if (is_prefix(*argv, "map")) {
		NEXT_ARG();

		if (!REQ_ARGS(2)) {
		p_err("incorrect map spec");
		return -1;
		}

		map_fd = map_parse_fd(&argc, &argv);
		if (map_fd < 0)
		return -1;
		}
		}

		obj = bpf_object__open(objfile);
		if (IS_ERR(obj)) {
		p_err("can't open objfile %s", objfile);
		return -1;
		goto close_map_fd;
		}

		err = bpf_object__load(obj);
		@@ -39,7 +57,10 @@ static int do_pin(int argc, char **argv)
		goto close_obj;
		}

		link = bpf_program__attach_iter(prog, NULL);
		if (map_fd >= 0)
		iter_opts.map_fd = map_fd;

		link = bpf_program__attach_iter(prog, &iter_opts);
		if (IS_ERR(link)) {
		err = PTR_ERR(link);
		p_err("attach_iter failed for program %s",
		@@ -62,14 +83,18 @@ close_link:
		bpf_link__destroy(link);
		close_obj:
		bpf_object__close(obj);
		close_map_fd:
		if (map_fd >= 0)
		close(map_fd);
		return err;
		}

		static int do_help(int argc, char **argv)
		{
		fprintf(stderr,
		"Usage: %1$s %2$s pin OBJ PATH\n"
		"Usage: %1$s %2$s pin OBJ PATH [map MAP]\n"
		" %1$s %2$s help\n"
		" " HELP_SPEC_MAP "\n"
		"",
		bin_name, "iter");

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