Some projects, for example xdp-tools [0], prefer to check in a minimized
vmlinux.h rather than the complete file which can get rather large.
However, when you try to add a minimized version of a complex struct (eg
struct xfrm_state), things can get quite complex if you're trying to
manually untangle and deduplicate the dependencies.
This commit teaches bpftool to do a minimized dump of a single type by
providing an optional root_id argument.
Example usage:
$ ./bpftool btf dump file ~/dev/linux/vmlinux | rg "STRUCT 'xfrm_state'"
[12643] STRUCT 'xfrm_state' size=912 vlen=58
$ ./bpftool btf dump file ~/dev/linux/vmlinux root_id 12643 format c
#ifndef __VMLINUX_H__
#define __VMLINUX_H__
[..]
struct xfrm_type_offload;
struct xfrm_sec_ctx;
struct xfrm_state {
possible_net_t xs_net;
union {
struct hlist_node gclist;
struct hlist_node bydst;
};
union {
struct hlist_node dev_gclist;
struct hlist_node bysrc;
};
struct hlist_node byspi;
[..]
[0]: https://github.com/xdp-project/xdp-tools/blob/master/headers/bpf/vmlinux.h
=== Changelog ===
Changes in v3:
* Make `root_id` a top level btf-dump argument rather than attached to `file`
* Update bash completion script
* Refactor root_type_ids checking to after btf handle creation
* Update help messages and fix existing man page inconsistency
Changes in v2:
* Add early error check for invalid BTF ID
Daniel Xu (4):
bpftool: man: Add missing format argument to command description
bpftool: btf: Validate root_type_ids early
bpftool: btf: Support dumping a single type from file
bpftool: bash: Add bash completion for root_id argument
.../bpf/bpftool/Documentation/bpftool-btf.rst | 7 ++--
tools/bpf/bpftool/bash-completion/bpftool | 7 ++--
tools/bpf/bpftool/btf.c | 33 ++++++++++++++++++-
3 files changed, 42 insertions(+), 5 deletions(-)
--
2.46.0
