1 // SPDX-License-Identifier: GPL-2.0 2 // Copyright (c) 2024 Andrea Righi <andrea.righi@canonical.com> 3 4 #include <linux/bpf.h> 5 #include <sched.h> 6 #include <unistd.h> 7 #include <bpf/bpf_helpers.h> 8 #include "bpf_misc.h" 9 10 char _license[] SEC("license") = "GPL"; 11 12 #define TASK_COMM_LEN 16 13 14 struct sample { 15 int pid; 16 long value; 17 char comm[16]; 18 }; 19 20 struct { 21 __uint(type, BPF_MAP_TYPE_RINGBUF); 22 } ringbuf SEC(".maps"); 23 24 int pid = 0; 25 long value = 0; 26 27 SEC("fentry/" SYS_PREFIX "sys_getpgid") test_ringbuf_n(void * ctx)28int test_ringbuf_n(void *ctx) 29 { 30 int cur_pid = bpf_get_current_pid_tgid() >> 32; 31 struct sample *sample; 32 33 if (cur_pid != pid) 34 return 0; 35 36 sample = bpf_ringbuf_reserve(&ringbuf, sizeof(*sample), 0); 37 if (!sample) 38 return 0; 39 40 sample->pid = pid; 41 sample->value = value; 42 bpf_get_current_comm(sample->comm, sizeof(sample->comm)); 43 44 bpf_ringbuf_submit(sample, 0); 45 46 return 0; 47 } 48