Manual: bpftool-iter

bpftool-iter(8)					   System Manager's Manual				     bpftool-iter(8)

Name
       bpftool-iter - tool to create BPF iterators

SYNOPSIS
       bpftool [OPTIONS] iter COMMAND

       OPTIONS := { { -j | --json } [{ -p | --pretty }] | { -d | --debug } }

       COMMANDS := { pin | help }

ITER COMMANDS
       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 [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 (e.g., one task, one bpf_map, etc.). User space can read kernel it‐
	      erator output through read() syscall.

	      The pin command creates a bpf iterator from OBJ, and pin it to PATH.  The PATH  should  be  located  in  bpffs
	      mount. It must not contain a dot 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, aggrega‐
	      tion, etc. without copying data to user space.

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

       bpftool iter help
	      Print short help message.

OPTIONS
       -h, --help
	      Print short help message (similar to bpftool help).

       -V, --version
	      Print  bpftool's version number (similar to bpftool version), the number of the libbpf version in use, and op‐
	      tional features that were included when bpftool was compiled. Optional features include linking  against	LLVM
	      or  libbfd  to provide the disassembler for JIT-ted programs (bpftool prog dump jited) and usage of BPF skele‐
	      tons (some features like bpftool prog profile or showing pids associated to BPF objects may rely on it).

       -j, --json
	      Generate JSON output. For commands that cannot produce JSON, this option has no effect.

       -p, --pretty
	      Generate human-readable JSON output. Implies -j.

       -d, --debug
	      Print all logs available, even debug-level information. This includes logs from libbpf as	 well  as  from	 the
	      verifier, when attempting to load programs.

EXAMPLES
       # bpftool iter pin bpf_iter_netlink.o /sys/fs/bpf/my_netlink

	  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),	 bpf-helpers(7),   bpftool(8),	 bpftool-btf(8),   bpftool-cgroup(8),	bpftool-feature(8),  bpftool-gen(8),
       bpftool-link(8), bpftool-map(8), bpftool-net(8), bpftool-perf(8), bpftool-prog(8), bpftool-struct_ops(8), bpftool-to‐
       ken(8)

													     bpftool-iter(8)