tools/testing/selftests/bpf/progs/cgroup_iter.c

   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 }