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Add a selftest for cgroup_iter. The selftest creates a mini cgroup tree
of the following structure:
ROOT (working cgroup)
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PARENT
/ \
CHILD1 CHILD2
and tests the following scenarios:
- invalid cgroup fd.
- pre-order walk over descendants from PARENT.
- post-order walk over descendants from PARENT.
- walk of ancestors from PARENT.
- process only a single object (i.e. PARENT).
- early termination.
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20220824233117.1312810-3-haoluo@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
40 lines
781 B
C
40 lines
781 B
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2022 Google */
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#include "bpf_iter.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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char _license[] SEC("license") = "GPL";
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int terminate_early = 0;
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u64 terminal_cgroup = 0;
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static inline u64 cgroup_id(struct cgroup *cgrp)
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{
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return cgrp->kn->id;
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}
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SEC("iter/cgroup")
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int cgroup_id_printer(struct bpf_iter__cgroup *ctx)
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{
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struct seq_file *seq = ctx->meta->seq;
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struct cgroup *cgrp = ctx->cgroup;
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/* epilogue */
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if (cgrp == NULL) {
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BPF_SEQ_PRINTF(seq, "epilogue\n");
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return 0;
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}
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/* prologue */
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if (ctx->meta->seq_num == 0)
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BPF_SEQ_PRINTF(seq, "prologue\n");
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BPF_SEQ_PRINTF(seq, "%8llu\n", cgroup_id(cgrp));
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if (terminal_cgroup == cgroup_id(cgrp))
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return 1;
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return terminate_early ? 1 : 0;
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}
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