1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2022 Google */ 3 #include <vmlinux.h> 4 #include <bpf/bpf_helpers.h> 5 #include <bpf/bpf_tracing.h> 6 7 char _license[] SEC("license") = "GPL"; 8 int terminate_early = 0; 9 u64 terminal_cgroup = 0; 10 11 static inline u64 cgroup_id(struct cgroup *cgrp) 12 { 13 return cgrp->kn->id; 14 } 15 16 SEC("iter/cgroup") 17 int cgroup_id_printer(struct bpf_iter__cgroup *ctx) 18 { 19 struct seq_file *seq = ctx->meta->seq; 20 struct cgroup *cgrp = ctx->cgroup; 21 22 /* epilogue */ 23 if (cgrp == NULL) { 24 BPF_SEQ_PRINTF(seq, "epilogue\n"); 25 return 0; 26 } 27 28 /* prologue */ 29 if (ctx->meta->seq_num == 0) 30 BPF_SEQ_PRINTF(seq, "prologue\n"); 31 32 BPF_SEQ_PRINTF(seq, "%8llu\n", cgroup_id(cgrp)); 33 34 if (terminal_cgroup == cgroup_id(cgrp)) 35 return 1; 36 37 return terminate_early ? 1 : 0; 38 } 39