selftests/bpf: Test parameterized task BPF iterators.

Test iterators of vma, files and tasks.

Ensure the API works appropriately to visit all tasks,
tasks in a process, or a particular task.

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20220926184957.208194-5-kuifeng@fb.com

1 files changed, 37 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_vma_offset.c b/tools/testing/selftests/bpf/progs/bpf_iter_vma_offset.c
new file mode 100644
index 000000000000..ee7455d2623a
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_vma_offset.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+#include "bpf_iter.h"
+#include <bpf/bpf_helpers.h>
+
+char _license[] SEC("license") = "GPL";
+
+__u32 unique_tgid_cnt = 0;
+uintptr_t address = 0;
+uintptr_t offset = 0;
+__u32 last_tgid = 0;
+__u32 pid = 0;
+__u32 page_shift = 0;
+
+SEC("iter/task_vma")
+int get_vma_offset(struct bpf_iter__task_vma *ctx)
+{
+	struct vm_area_struct *vma = ctx->vma;
+	struct seq_file *seq = ctx->meta->seq;
+	struct task_struct *task = ctx->task;
+
+	if (task == NULL || vma == NULL)
+		return 0;
+
+	if (last_tgid != task->tgid)
+		unique_tgid_cnt++;
+	last_tgid = task->tgid;
+
+	if (task->tgid != pid)
+		return 0;
+
+	if (vma->vm_start <= address && vma->vm_end > address) {
+		offset = address - vma->vm_start + (vma->vm_pgoff << page_shift);
+		BPF_SEQ_PRINTF(seq, "OK\n");
+	}
+	return 0;
+}