linux-stable/samples/bpf/test_current_task_under_cgroup_kern.c
Daniel T. Lee 3677d0a131 samples: bpf: Refactor kprobe tracing programs with libbpf
For the problem of increasing fragmentation of the bpf loader programs,
instead of using bpf_loader.o, which is used in samples/bpf, this
commit refactors the existing kprobe tracing programs with libbbpf
bpf loader.

    - For kprobe events pointing to system calls, the SYSCALL() macro in
    trace_common.h was used.
    - Adding a kprobe event and attaching a bpf program to it was done
    through bpf_program_attach().
    - Instead of using the existing BPF MAP definition, MAP definition
    has been refactored with the new BTF-defined MAP format.

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200823085334.9413-3-danieltimlee@gmail.com
2020-08-24 20:59:35 -07:00

44 lines
1.1 KiB
C

/* Copyright (c) 2016 Sargun Dhillon <sargun@sargun.me>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#include <linux/ptrace.h>
#include <uapi/linux/bpf.h>
#include <linux/version.h>
#include <bpf/bpf_helpers.h>
#include <uapi/linux/utsname.h>
#include "trace_common.h"
struct {
__uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
__uint(key_size, sizeof(u32));
__uint(value_size, sizeof(u32));
__uint(max_entries, 1);
} cgroup_map SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, u32);
__type(value, u64);
__uint(max_entries, 1);
} perf_map SEC(".maps");
/* Writes the last PID that called sync to a map at index 0 */
SEC("kprobe/" SYSCALL(sys_sync))
int bpf_prog1(struct pt_regs *ctx)
{
u64 pid = bpf_get_current_pid_tgid();
int idx = 0;
if (!bpf_current_task_under_cgroup(&cgroup_map, 0))
return 0;
bpf_map_update_elem(&perf_map, &idx, &pid, BPF_ANY);
return 0;
}
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;