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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
   3 #include "bpf_iter.h"
   4 #include <bpf/bpf_helpers.h>
   5
   6 char _license[] SEC("license") = "GPL";
   7
   8 __u32 unique_tgid_cnt = 0;
   9 uintptr_t address = 0;
  10 uintptr_t offset = 0;
  11 __u32 last_tgid = 0;
  12 __u32 pid = 0;
  13 __u32 page_shift = 0;
  14
  15 SEC("iter/task_vma")
  16 int get_vma_offset(struct bpf_iter__task_vma *ctx)
  17 {
  18         struct vm_area_struct *vma = ctx->vma;
  19         struct seq_file *seq = ctx->meta->seq;
  20         struct task_struct *task = ctx->task;
  21
  22         if (task == NULL || vma == NULL)
  23                 return 0;
  24
  25         if (last_tgid != task->tgid)
  26                 unique_tgid_cnt++;
  27         last_tgid = task->tgid;
  28
  29         if (task->tgid != pid)
  30                 return 0;
  31
  32         if (vma->vm_start <= address && vma->vm_end > address) {
  33                 offset = address - vma->vm_start + (vma->vm_pgoff << page_shift);
  34                 BPF_SEQ_PRINTF(seq, "OK\n");
  35         }
  36         return 0;
  37 }