Commit 1b9ed84e authored by Quentin Monnet's avatar Quentin Monnet Committed by Alexei Starovoitov
Browse files

bpf: add new BPF_BTF_GET_NEXT_ID syscall command 



Add a new command for the bpf() system call: BPF_BTF_GET_NEXT_ID is used
to cycle through all BTF objects loaded on the system.

The motivation is to be able to inspect (list) all BTF objects presents
on the system.

Signed-off-by: default avatarQuentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 09845436

include/linux/bpf.h

+3 −0
Original line number Diff line number Diff line
@@ -24,6 +24,9 @@ struct seq_file; 
struct btf;

struct btf_type;



extern struct idr btf_idr;

extern spinlock_t btf_idr_lock;



/* map is generic key/value storage optionally accesible by eBPF programs */

struct bpf_map_ops {

	/* funcs callable from userspace (via syscall) */

include/uapi/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -106,6 +106,7 @@ enum bpf_cmd { 
	BPF_TASK_FD_QUERY,

	BPF_MAP_LOOKUP_AND_DELETE_ELEM,

	BPF_MAP_FREEZE,

	BPF_BTF_GET_NEXT_ID,

};



enum bpf_map_type {

kernel/bpf/btf.c

+2 −2
Original line number Diff line number Diff line
@@ -195,8 +195,8 @@ 
	     i < btf_type_vlen(struct_type);					\

	     i++, member++)



static DEFINE_IDR(btf_idr);

static DEFINE_SPINLOCK(btf_idr_lock);

DEFINE_IDR(btf_idr);

DEFINE_SPINLOCK(btf_idr_lock);



struct btf {

	void *data;

kernel/bpf/syscall.c

+4 −0
Original line number Diff line number Diff line
@@ -2884,6 +2884,10 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz 
		err = bpf_obj_get_next_id(&attr, uattr,

					  &map_idr, &map_idr_lock);

		break;

	case BPF_BTF_GET_NEXT_ID:

		err = bpf_obj_get_next_id(&attr, uattr,

					  &btf_idr, &btf_idr_lock);

		break;

	case BPF_PROG_GET_FD_BY_ID:

		err = bpf_prog_get_fd_by_id(&attr);

		break;

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