On Mon, Sep 26, 2022 at 11:50 AM Kui-Feng Lee <kuifeng@xxxxxx> wrote:
>
> Allow creating an iterator that loops through resources of one
> thread/process.
>
> People could only create iterators to loop through all resources of
> files, vma, and tasks in the system, even though they were interested
> in only the resources of a specific task or process. Passing the
> additional parameters, people can now create an iterator to go
> through all resources or only the resources of a task.
>
> Signed-off-by: Kui-Feng Lee <kuifeng@xxxxxx>
> Acked-by: Yonghong Song <yhs@xxxxxx>
> ---
> include/linux/bpf.h | 25 +++++
> include/uapi/linux/bpf.h | 6 ++
> kernel/bpf/task_iter.c | 192 +++++++++++++++++++++++++++++----
> tools/include/uapi/linux/bpf.h | 6 ++
> 4 files changed, 207 insertions(+), 22 deletions(-)
>
[...]
> +static int bpf_iter_attach_task(struct bpf_prog *prog,
> + union bpf_iter_link_info *linfo,
> + struct bpf_iter_aux_info *aux)
> +{
> + unsigned int flags;
> + struct pid_namespace *ns;
> + struct pid *pid;
> + pid_t tgid;
> +
> + if ((!!linfo->task.tid + !!linfo->task.pid + !!linfo->task.pid_fd) > 1)
> + return -EINVAL;
> +
> + aux->task.type = BPF_TASK_ITER_ALL;
> + if (linfo->task.tid != 0) {
> + aux->task.type = BPF_TASK_ITER_TID;
> + aux->task.pid = linfo->task.tid;
> + }
> + if (linfo->task.pid != 0) {
> + aux->task.type = BPF_TASK_ITER_TGID;
> + aux->task.pid = linfo->task.pid;
> + }
> + if (linfo->task.pid_fd != 0) {
> + aux->task.type = BPF_TASK_ITER_TGID;
> + ns = task_active_pid_ns(current);
> + if (IS_ERR(ns))
> + return PTR_ERR(ns);
doesn't seem like task_active_pid_ns() can fail (other places in
kernel never handle NULL or IS_ERR for this), so I dropped this IS_ERR
check
> +
> + pid = pidfd_get_pid(linfo->task.pid_fd, &flags);
> + if (IS_ERR(pid))
> + return PTR_ERR(pid);
> +
> + tgid = pid_nr_ns(pid, ns);
> + aux->task.pid = tgid;
> + put_pid(pid);
> + }
> +
> + return 0;
> +}
> +
[...]
