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1.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)2 3============4bpftool-iter5============6-------------------------------------------------------------------------------7tool to create BPF iterators8-------------------------------------------------------------------------------9 10:Manual section: 811 12.. include:: substitutions.rst13 14SYNOPSIS15========16 17**bpftool** [*OPTIONS*] **iter** *COMMAND*18 19*OPTIONS* := { |COMMON_OPTIONS| }20 21*COMMANDS* := { **pin** | **help** }22 23ITER COMMANDS24=============25 26| **bpftool** **iter pin** *OBJ* *PATH* [**map** *MAP*]27| **bpftool** **iter help**28|29| *OBJ* := /a/file/of/bpf_iter_target.o30| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* }31 32DESCRIPTION33===========34bpftool iter pin *OBJ* *PATH* [map *MAP*]35 A bpf iterator combines a kernel iterating of particular kernel data (e.g.,36 tasks, bpf_maps, etc.) and a bpf program called for each kernel data object37 (e.g., one task, one bpf_map, etc.). User space can *read* kernel iterator38 output through *read()* syscall.39 40 The *pin* command creates a bpf iterator from *OBJ*, and pin it to *PATH*.41 The *PATH* should be located in *bpffs* mount. It must not contain a dot42 character ('.'), which is reserved for future extensions of *bpffs*.43 44 Map element bpf iterator requires an additional parameter *MAP* so bpf45 program can iterate over map elements for that map. User can have a bpf46 program in kernel to run with each map element, do checking, filtering,47 aggregation, etc. without copying data to user space.48 49 User can then *cat PATH* to see the bpf iterator output.50 51bpftool iter help52 Print short help message.53 54OPTIONS55=======56.. include:: common_options.rst57 58EXAMPLES59========60**# bpftool iter pin bpf_iter_netlink.o /sys/fs/bpf/my_netlink**61 62::63 64 Create a file-based bpf iterator from bpf_iter_netlink.o and pin it65 to /sys/fs/bpf/my_netlink66 67**# bpftool iter pin bpf_iter_hashmap.o /sys/fs/bpf/my_hashmap map id 20**68 69::70 71 Create a file-based bpf iterator from bpf_iter_hashmap.o and map with72 id 20, and pin it to /sys/fs/bpf/my_hashmap73