perfbuf-output.bpf.c

// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/* Copyright (c) 2020 Andrii Nakryiko */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "common.h"

char LICENSE[] SEC("license") = "Dual BSD/GPL";

/* BPF perfbuf map */
struct {
	__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
	__uint(key_size, sizeof(int));
	__uint(value_size, sizeof(int));
} pb SEC(".maps");

struct {
	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
	__uint(max_entries, 1);
	__type(key, int);
	__type(value, struct event);
} heap SEC(".maps");

SEC("tp/sched/sched_process_exec")
int handle_exec(struct trace_event_raw_sched_process_exec *ctx)
{
	unsigned fname_off = ctx->__data_loc_filename & 0xFFFF;
	struct event *e;
	int zero = 0;
	
	e = bpf_map_lookup_elem(&heap, &zero);
	if (!e) /* can't happen */
		return 0;

	e->pid = bpf_get_current_pid_tgid() >> 32;
	bpf_get_current_comm(&e->comm, sizeof(e->comm));
	bpf_probe_read_str(&e->filename, sizeof(e->filename), (void *)ctx + fname_off);

	bpf_perf_event_output(ctx, &pb, BPF_F_CURRENT_CPU, e, sizeof(*e));
	return 0;
}