On Tue, Aug 9, 2022 at 12:54 PM Kui-Feng Lee <kuifeng@xxxxxx> wrote:
>
> Allow creating an iterator that loops through resources of one task/thread.
>
> 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>
> ---
> include/linux/bpf.h | 8 ++
> include/uapi/linux/bpf.h | 36 +++++++++
> kernel/bpf/task_iter.c | 134 +++++++++++++++++++++++++++------
> tools/include/uapi/linux/bpf.h | 36 +++++++++
> 4 files changed, 190 insertions(+), 24 deletions(-)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 11950029284f..bef81324e5f1 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -1718,6 +1718,14 @@ int bpf_obj_get_user(const char __user *pathname, int flags);
>
> struct bpf_iter_aux_info {
> struct bpf_map *map;
> + struct {
> + enum bpf_iter_task_type type;
> + union {
> + u32 tid;
> + u32 tgid;
> + u32 pid_fd;
> + };
> + } task;
> };
>
> typedef int (*bpf_iter_attach_target_t)(struct bpf_prog *prog,
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index ffcbf79a556b..3d0b9e34089f 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -87,10 +87,46 @@ struct bpf_cgroup_storage_key {
> __u32 attach_type; /* program attach type (enum bpf_attach_type) */
> };
>
> +/*
> + * The task type of iterators.
> + *
> + * For BPF task iterators, they can be parameterized with various
> + * parameters to visit only some of tasks.
> + *
> + * BPF_TASK_ITER_ALL (default)
> + * Iterate over resources of every task.
> + *
> + * BPF_TASK_ITER_TID
> + * Iterate over resources of a task/tid.
> + *
> + * BPF_TASK_ITER_TGID
> + * Iterate over reosurces of evevry task of a process / task group.
> + *
> + * BPF_TASK_ITER_PIDFD
> + * Iterate over resources of every task of a process /task group specified by a pidfd.
> + */
> +enum bpf_iter_task_type {
> + BPF_TASK_ITER_ALL = 0,
> + BPF_TASK_ITER_TID,
> + BPF_TASK_ITER_TGID,
> + BPF_TASK_ITER_PIDFD,
> +};
> +
> union bpf_iter_link_info {
> struct {
> __u32 map_fd;
> } map;
> + /*
> + * Parameters of task iterators.
> + */
> + struct {
> + enum bpf_iter_task_type type;
> + union {
> + __u32 tid;
> + __u32 tgid;
> + __u32 pid_fd;
> + };
Sorry I'm late to this discussion, but
with enum and with union we kinda tell
the kernel the same information twice.
Here is how the selftest looks:
+ linfo.task.tid = getpid();
+ linfo.task.type = BPF_TASK_ITER_TID;
first line -> use tid.
second line -> yeah. I really meant the tid.
Instead of union and type can we do:
> + __u32 tid;
> + __u32 tgid;
> + __u32 pid_fd;
as 3 separate fields?
The kernel would have to check that only one
of them is set.
I could have missed an earlier discussion on this subj.
