From 5d999994e05d62d4f53059540652014cf83cddfe Mon Sep 17 00:00:00 2001 From: Joe Stringer Date: Tue, 2 Mar 2021 09:19:39 -0800 Subject: [PATCH] bpf: Document BPF_PROG_QUERY syscall command MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Commit 468e2f64d220 ("bpf: introduce BPF_PROG_QUERY command") originally introduced this, but there have been several additions since then. Unlike BPF_PROG_ATTACH, it appears that the sockmap progs are not able to be queried so far. Signed-off-by: Joe Stringer Signed-off-by: Alexei Starovoitov Reviewed-by: Quentin Monnet Acked-by: Toke Høiland-Jørgensen Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20210302171947.2268128-8-joe@cilium.io --- include/uapi/linux/bpf.h | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index a6cd665..0cf92ef 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -389,6 +389,43 @@ union bpf_iter_link_info { * Obtain information about eBPF programs associated with the * specified *attach_type* hook. * + * The *target_fd* must be a valid file descriptor for a kernel + * object which depends on the attach type of *attach_bpf_fd*: + * + * **BPF_PROG_TYPE_CGROUP_DEVICE**, + * **BPF_PROG_TYPE_CGROUP_SKB**, + * **BPF_PROG_TYPE_CGROUP_SOCK**, + * **BPF_PROG_TYPE_CGROUP_SOCK_ADDR**, + * **BPF_PROG_TYPE_CGROUP_SOCKOPT**, + * **BPF_PROG_TYPE_CGROUP_SYSCTL**, + * **BPF_PROG_TYPE_SOCK_OPS** + * + * Control Group v2 hierarchy with the eBPF controller + * enabled. Requires the kernel to be compiled with + * **CONFIG_CGROUP_BPF**. + * + * **BPF_PROG_TYPE_FLOW_DISSECTOR** + * + * Network namespace (eg /proc/self/ns/net). + * + * **BPF_PROG_TYPE_LIRC_MODE2** + * + * LIRC device path (eg /dev/lircN). Requires the kernel + * to be compiled with **CONFIG_BPF_LIRC_MODE2**. + * + * **BPF_PROG_QUERY** always fetches the number of programs + * attached and the *attach_flags* which were used to attach those + * programs. Additionally, if *prog_ids* is nonzero and the number + * of attached programs is less than *prog_cnt*, populates + * *prog_ids* with the eBPF program ids of the programs attached + * at *target_fd*. + * + * The following flags may alter the result: + * + * **BPF_F_QUERY_EFFECTIVE** + * Only return information regarding programs which are + * currently effective at the specified *target_fd*. + * * Return * Returns zero on success. On error, -1 is returned and *errno* * is set appropriately. -- 2.7.4