tools/bpftool: Add bpf_iter support for bptool
Currently, only one command is supported bpftool iter pin <bpf_prog.o> <path> It will pin the trace/iter bpf program in the object file <bpf_prog.o> to the <path> where <path> should be on a bpffs mount. For example, $ bpftool iter pin ./bpf_iter_ipv6_route.o \ /sys/fs/bpf/my_route User can then do a `cat` to print out the results: $ cat /sys/fs/bpf/my_route fe800000000000000000000000000000 40 00000000000000000000000000000000 ... 00000000000000000000000000000000 00 00000000000000000000000000000000 ... 00000000000000000000000000000001 80 00000000000000000000000000000000 ... fe800000000000008c0162fffebdfd57 80 00000000000000000000000000000000 ... ff000000000000000000000000000000 08 00000000000000000000000000000000 ... 00000000000000000000000000000000 00 00000000000000000000000000000000 ... The implementation for ipv6_route iterator is in one of subsequent patches. This patch also added BPF_LINK_TYPE_ITER to link query. In the future, we may add additional parameters to pin command by parameterizing the bpf iterator. For example, a map_id or pid may be added to let bpf program only traverses a single map or task, similar to kernel seq_file single_open(). We may also add introspection command for targets/iterators by leveraging the bpf_iter itself. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200509175920.2477247-1-yhs@fb.com
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Alexei Starovoitov
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83
tools/bpf/bpftool/Documentation/bpftool-iter.rst
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83
tools/bpf/bpftool/Documentation/bpftool-iter.rst
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============
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bpftool-iter
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============
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-------------------------------------------------------------------------------
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tool to create BPF iterators
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-------------------------------------------------------------------------------
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:Manual section: 8
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SYNOPSIS
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========
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**bpftool** [*OPTIONS*] **iter** *COMMAND*
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*COMMANDS* := { **pin** | **help** }
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ITER COMMANDS
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===================
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| **bpftool** **iter pin** *OBJ* *PATH*
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| **bpftool** **iter help**
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| *OBJ* := /a/file/of/bpf_iter_target.o
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DESCRIPTION
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===========
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**bpftool iter pin** *OBJ* *PATH*
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A bpf iterator combines a kernel iterating of
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particular kernel data (e.g., tasks, bpf_maps, etc.)
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and a bpf program called for each kernel data object
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(e.g., one task, one bpf_map, etc.). User space can
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*read* kernel iterator output through *read()* syscall.
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The *pin* command creates a bpf iterator from *OBJ*,
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and pin it to *PATH*. The *PATH* should be located
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in *bpffs* mount. It must not contain a dot
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character ('.'), which is reserved for future extensions
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of *bpffs*.
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User can then *cat PATH* to see the bpf iterator output.
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**bpftool iter help**
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Print short help message.
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OPTIONS
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=======
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-h, --help
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Print short generic help message (similar to **bpftool help**).
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-V, --version
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Print version number (similar to **bpftool version**).
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-d, --debug
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Print all logs available, even debug-level information. This
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includes logs from libbpf as well as from the verifier, when
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attempting to load programs.
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EXAMPLES
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========
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**# bpftool iter pin bpf_iter_netlink.o /sys/fs/bpf/my_netlink**
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::
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Create a file-based bpf iterator from bpf_iter_netlink.o and pin it
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to /sys/fs/bpf/my_netlink
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SEE ALSO
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========
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**bpf**\ (2),
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**bpf-helpers**\ (7),
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**bpftool**\ (8),
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**bpftool-prog**\ (8),
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**bpftool-map**\ (8),
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**bpftool-link**\ (8),
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**bpftool-cgroup**\ (8),
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**bpftool-feature**\ (8),
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**bpftool-net**\ (8),
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**bpftool-perf**\ (8),
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**bpftool-btf**\ (8)
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**bpftool-gen**\ (8)
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**bpftool-struct_ops**\ (8)
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@ -610,6 +610,19 @@ _bpftool()
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;;
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;;
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esac
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esac
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;;
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;;
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iter)
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case $command in
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pin)
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_filedir
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return 0
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;;
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*)
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[[ $prev == $object ]] && \
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COMPREPLY=( $( compgen -W 'pin help' \
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-- "$cur" ) )
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;;
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esac
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;;
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map)
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map)
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local MAP_TYPE='id pinned name'
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local MAP_TYPE='id pinned name'
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case $command in
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case $command in
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88
tools/bpf/bpftool/iter.c
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tools/bpf/bpftool/iter.c
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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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// Copyright (C) 2020 Facebook
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#define _GNU_SOURCE
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#include <linux/err.h>
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#include <bpf/libbpf.h>
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#include "main.h"
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static int do_pin(int argc, char **argv)
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{
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const char *objfile, *path;
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struct bpf_program *prog;
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struct bpf_object *obj;
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struct bpf_link *link;
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int err;
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if (!REQ_ARGS(2))
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usage();
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objfile = GET_ARG();
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path = GET_ARG();
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obj = bpf_object__open(objfile);
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if (IS_ERR(obj)) {
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p_err("can't open objfile %s", objfile);
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return -1;
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}
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err = bpf_object__load(obj);
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if (err) {
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p_err("can't load objfile %s", objfile);
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goto close_obj;
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}
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prog = bpf_program__next(NULL, obj);
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if (!prog) {
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p_err("can't find bpf program in objfile %s", objfile);
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goto close_obj;
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}
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link = bpf_program__attach_iter(prog, NULL);
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if (IS_ERR(link)) {
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err = PTR_ERR(link);
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p_err("attach_iter failed for program %s",
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bpf_program__name(prog));
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goto close_obj;
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}
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err = mount_bpffs_for_pin(path);
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if (err)
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goto close_link;
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err = bpf_link__pin(link, path);
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if (err) {
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p_err("pin_iter failed for program %s to path %s",
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bpf_program__name(prog), path);
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goto close_link;
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}
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close_link:
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bpf_link__destroy(link);
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close_obj:
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bpf_object__close(obj);
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return err;
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}
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static int do_help(int argc, char **argv)
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{
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fprintf(stderr,
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"Usage: %s %s pin OBJ PATH\n"
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" %s %s help\n"
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"\n",
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bin_name, argv[-2], bin_name, argv[-2]);
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return 0;
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}
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static const struct cmd cmds[] = {
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{ "help", do_help },
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{ "pin", do_pin },
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{ 0 }
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};
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int do_iter(int argc, char **argv)
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{
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return cmd_select(cmds, argc, argv, do_help);
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}
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@ -16,6 +16,7 @@ static const char * const link_type_name[] = {
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[BPF_LINK_TYPE_RAW_TRACEPOINT] = "raw_tracepoint",
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[BPF_LINK_TYPE_RAW_TRACEPOINT] = "raw_tracepoint",
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[BPF_LINK_TYPE_TRACING] = "tracing",
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[BPF_LINK_TYPE_TRACING] = "tracing",
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[BPF_LINK_TYPE_CGROUP] = "cgroup",
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[BPF_LINK_TYPE_CGROUP] = "cgroup",
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[BPF_LINK_TYPE_ITER] = "iter",
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};
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};
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static int link_parse_fd(int *argc, char ***argv)
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static int link_parse_fd(int *argc, char ***argv)
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" %s batch file FILE\n"
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" %s batch file FILE\n"
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" %s version\n"
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" %s version\n"
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"\n"
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"\n"
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" OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops }\n"
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" OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops | iter }\n"
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" " HELP_SPEC_OPTIONS "\n"
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" " HELP_SPEC_OPTIONS "\n"
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"",
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"",
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bin_name, bin_name, bin_name);
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bin_name, bin_name, bin_name);
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{ "btf", do_btf },
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{ "btf", do_btf },
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{ "gen", do_gen },
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{ "gen", do_gen },
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{ "struct_ops", do_struct_ops },
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{ "struct_ops", do_struct_ops },
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{ "iter", do_iter },
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{ "version", do_version },
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{ "version", do_version },
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{ 0 }
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{ 0 }
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};
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};
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int do_btf(int argc, char **argv);
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int do_btf(int argc, char **argv);
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int do_gen(int argc, char **argv);
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int do_gen(int argc, char **argv);
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int do_struct_ops(int argc, char **argv);
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int do_struct_ops(int argc, char **argv);
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int do_iter(int argc, char **argv);
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int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what);
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int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what);
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int prog_parse_fd(int *argc, char ***argv);
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int prog_parse_fd(int *argc, char ***argv);
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