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| #include <linux/init.h> |
| #include <linux/namei.h> |
| #include <linux/pid_namespace.h> |
| #include <linux/fs.h> |
| #include <linux/fdtable.h> |
| #include <linux/filter.h> |
| #include <linux/btf_ids.h> |
| |
| struct bpf_iter_seq_task_common { |
| <------>struct pid_namespace *ns; |
| }; |
| |
| struct bpf_iter_seq_task_info { |
| <------> |
| <------> * this is assumed by {init, fini}_seq_pidns() callback functions. |
| <------> */ |
| <------>struct bpf_iter_seq_task_common common; |
| <------>u32 tid; |
| }; |
| |
| static struct task_struct *task_seq_get_next(struct pid_namespace *ns, |
| <------><------><------><------><------> u32 *tid, |
| <------><------><------><------><------> bool skip_if_dup_files) |
| { |
| <------>struct task_struct *task = NULL; |
| <------>struct pid *pid; |
| |
| <------>rcu_read_lock(); |
| retry: |
| <------>pid = find_ge_pid(*tid, ns); |
| <------>if (pid) { |
| <------><------>*tid = pid_nr_ns(pid, ns); |
| <------><------>task = get_pid_task(pid, PIDTYPE_PID); |
| <------><------>if (!task) { |
| <------><------><------>++*tid; |
| <------><------><------>goto retry; |
| <------><------>} else if (skip_if_dup_files && task->tgid != task->pid && |
| <------><------><------> task->files == task->group_leader->files) { |
| <------><------><------>put_task_struct(task); |
| <------><------><------>task = NULL; |
| <------><------><------>++*tid; |
| <------><------><------>goto retry; |
| <------><------>} |
| <------>} |
| <------>rcu_read_unlock(); |
| |
| <------>return task; |
| } |
| |
| static void *task_seq_start(struct seq_file *seq, loff_t *pos) |
| { |
| <------>struct bpf_iter_seq_task_info *info = seq->private; |
| <------>struct task_struct *task; |
| |
| <------>task = task_seq_get_next(info->common.ns, &info->tid, false); |
| <------>if (!task) |
| <------><------>return NULL; |
| |
| <------>if (*pos == 0) |
| <------><------>++*pos; |
| <------>return task; |
| } |
| |
| static void *task_seq_next(struct seq_file *seq, void *v, loff_t *pos) |
| { |
| <------>struct bpf_iter_seq_task_info *info = seq->private; |
| <------>struct task_struct *task; |
| |
| <------>++*pos; |
| <------>++info->tid; |
| <------>put_task_struct((struct task_struct *)v); |
| <------>task = task_seq_get_next(info->common.ns, &info->tid, false); |
| <------>if (!task) |
| <------><------>return NULL; |
| |
| <------>return task; |
| } |
| |
| struct bpf_iter__task { |
| <------>__bpf_md_ptr(struct bpf_iter_meta *, meta); |
| <------>__bpf_md_ptr(struct task_struct *, task); |
| }; |
| |
| DEFINE_BPF_ITER_FUNC(task, struct bpf_iter_meta *meta, struct task_struct *task) |
| |
| static int __task_seq_show(struct seq_file *seq, struct task_struct *task, |
| <------><------><------> bool in_stop) |
| { |
| <------>struct bpf_iter_meta meta; |
| <------>struct bpf_iter__task ctx; |
| <------>struct bpf_prog *prog; |
| |
| <------>meta.seq = seq; |
| <------>prog = bpf_iter_get_info(&meta, in_stop); |
| <------>if (!prog) |
| <------><------>return 0; |
| |
| <------>meta.seq = seq; |
| <------>ctx.meta = &meta; |
| <------>ctx.task = task; |
| <------>return bpf_iter_run_prog(prog, &ctx); |
| } |
| |
| static int task_seq_show(struct seq_file *seq, void *v) |
| { |
| <------>return __task_seq_show(seq, v, false); |
| } |
| |
| static void task_seq_stop(struct seq_file *seq, void *v) |
| { |
| <------>if (!v) |
| <------><------>(void)__task_seq_show(seq, v, true); |
| <------>else |
| <------><------>put_task_struct((struct task_struct *)v); |
| } |
| |
| static const struct seq_operations task_seq_ops = { |
| <------>.start = task_seq_start, |
| <------>.next = task_seq_next, |
| <------>.stop = task_seq_stop, |
| <------>.show = task_seq_show, |
| }; |
| |
| struct bpf_iter_seq_task_file_info { |
| <------> |
| <------> * this is assumed by {init, fini}_seq_pidns() callback functions. |
| <------> */ |
| <------>struct bpf_iter_seq_task_common common; |
| <------>struct task_struct *task; |
| <------>struct files_struct *files; |
| <------>u32 tid; |
| <------>u32 fd; |
| }; |
| |
| static struct file * |
| task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info) |
| { |
| <------>struct pid_namespace *ns = info->common.ns; |
| <------>u32 curr_tid = info->tid, max_fds; |
| <------>struct files_struct *curr_files; |
| <------>struct task_struct *curr_task; |
| <------>int curr_fd = info->fd; |
| |
| <------> |
| <------> * it held a reference to the task/files_struct/file. |
| <------> * Otherwise, it does not hold any reference. |
| <------> */ |
| again: |
| <------>if (info->task) { |
| <------><------>curr_task = info->task; |
| <------><------>curr_files = info->files; |
| <------><------>curr_fd = info->fd; |
| <------>} else { |
| <------><------>curr_task = task_seq_get_next(ns, &curr_tid, true); |
| <------><------>if (!curr_task) { |
| <------><------><------>info->task = NULL; |
| <------><------><------>info->files = NULL; |
| <------><------><------>info->tid = curr_tid; |
| <------><------><------>return NULL; |
| <------><------>} |
| |
| <------><------>curr_files = get_files_struct(curr_task); |
| <------><------>if (!curr_files) { |
| <------><------><------>put_task_struct(curr_task); |
| <------><------><------>curr_tid = curr_tid + 1; |
| <------><------><------>info->fd = 0; |
| <------><------><------>goto again; |
| <------><------>} |
| |
| <------><------>info->files = curr_files; |
| <------><------>info->task = curr_task; |
| <------><------>if (curr_tid == info->tid) { |
| <------><------><------>curr_fd = info->fd; |
| <------><------>} else { |
| <------><------><------>info->tid = curr_tid; |
| <------><------><------>curr_fd = 0; |
| <------><------>} |
| <------>} |
| |
| <------>rcu_read_lock(); |
| <------>max_fds = files_fdtable(curr_files)->max_fds; |
| <------>for (; curr_fd < max_fds; curr_fd++) { |
| <------><------>struct file *f; |
| |
| <------><------>f = fcheck_files(curr_files, curr_fd); |
| <------><------>if (!f) |
| <------><------><------>continue; |
| <------><------>if (!get_file_rcu(f)) |
| <------><------><------>continue; |
| |
| <------><------> |
| <------><------>info->fd = curr_fd; |
| <------><------>rcu_read_unlock(); |
| <------><------>return f; |
| <------>} |
| |
| <------> |
| <------>rcu_read_unlock(); |
| <------>put_files_struct(curr_files); |
| <------>put_task_struct(curr_task); |
| <------>info->task = NULL; |
| <------>info->files = NULL; |
| <------>info->fd = 0; |
| <------>curr_tid = ++(info->tid); |
| <------>goto again; |
| } |
| |
| static void *task_file_seq_start(struct seq_file *seq, loff_t *pos) |
| { |
| <------>struct bpf_iter_seq_task_file_info *info = seq->private; |
| <------>struct file *file; |
| |
| <------>info->task = NULL; |
| <------>info->files = NULL; |
| <------>file = task_file_seq_get_next(info); |
| <------>if (file && *pos == 0) |
| <------><------>++*pos; |
| |
| <------>return file; |
| } |
| |
| static void *task_file_seq_next(struct seq_file *seq, void *v, loff_t *pos) |
| { |
| <------>struct bpf_iter_seq_task_file_info *info = seq->private; |
| |
| <------>++*pos; |
| <------>++info->fd; |
| <------>fput((struct file *)v); |
| <------>return task_file_seq_get_next(info); |
| } |
| |
| struct bpf_iter__task_file { |
| <------>__bpf_md_ptr(struct bpf_iter_meta *, meta); |
| <------>__bpf_md_ptr(struct task_struct *, task); |
| <------>u32 fd __aligned(8); |
| <------>__bpf_md_ptr(struct file *, file); |
| }; |
| |
| DEFINE_BPF_ITER_FUNC(task_file, struct bpf_iter_meta *meta, |
| <------><------> struct task_struct *task, u32 fd, |
| <------><------> struct file *file) |
| |
| static int __task_file_seq_show(struct seq_file *seq, struct file *file, |
| <------><------><------><------>bool in_stop) |
| { |
| <------>struct bpf_iter_seq_task_file_info *info = seq->private; |
| <------>struct bpf_iter__task_file ctx; |
| <------>struct bpf_iter_meta meta; |
| <------>struct bpf_prog *prog; |
| |
| <------>meta.seq = seq; |
| <------>prog = bpf_iter_get_info(&meta, in_stop); |
| <------>if (!prog) |
| <------><------>return 0; |
| |
| <------>ctx.meta = &meta; |
| <------>ctx.task = info->task; |
| <------>ctx.fd = info->fd; |
| <------>ctx.file = file; |
| <------>return bpf_iter_run_prog(prog, &ctx); |
| } |
| |
| static int task_file_seq_show(struct seq_file *seq, void *v) |
| { |
| <------>return __task_file_seq_show(seq, v, false); |
| } |
| |
| static void task_file_seq_stop(struct seq_file *seq, void *v) |
| { |
| <------>struct bpf_iter_seq_task_file_info *info = seq->private; |
| |
| <------>if (!v) { |
| <------><------>(void)__task_file_seq_show(seq, v, true); |
| <------>} else { |
| <------><------>fput((struct file *)v); |
| <------><------>put_files_struct(info->files); |
| <------><------>put_task_struct(info->task); |
| <------><------>info->files = NULL; |
| <------><------>info->task = NULL; |
| <------>} |
| } |
| |
| static int init_seq_pidns(void *priv_data, struct bpf_iter_aux_info *aux) |
| { |
| <------>struct bpf_iter_seq_task_common *common = priv_data; |
| |
| <------>common->ns = get_pid_ns(task_active_pid_ns(current)); |
| <------>return 0; |
| } |
| |
| static void fini_seq_pidns(void *priv_data) |
| { |
| <------>struct bpf_iter_seq_task_common *common = priv_data; |
| |
| <------>put_pid_ns(common->ns); |
| } |
| |
| static const struct seq_operations task_file_seq_ops = { |
| <------>.start = task_file_seq_start, |
| <------>.next = task_file_seq_next, |
| <------>.stop = task_file_seq_stop, |
| <------>.show = task_file_seq_show, |
| }; |
| |
| BTF_ID_LIST(btf_task_file_ids) |
| BTF_ID(struct, task_struct) |
| BTF_ID(struct, file) |
| |
| static const struct bpf_iter_seq_info task_seq_info = { |
| <------>.seq_ops = &task_seq_ops, |
| <------>.init_seq_private = init_seq_pidns, |
| <------>.fini_seq_private = fini_seq_pidns, |
| <------>.seq_priv_size = sizeof(struct bpf_iter_seq_task_info), |
| }; |
| |
| static struct bpf_iter_reg task_reg_info = { |
| <------>.target = "task", |
| <------>.ctx_arg_info_size = 1, |
| <------>.ctx_arg_info = { |
| <------><------>{ offsetof(struct bpf_iter__task, task), |
| <------><------> PTR_TO_BTF_ID_OR_NULL }, |
| <------>}, |
| <------>.seq_info = &task_seq_info, |
| }; |
| |
| static const struct bpf_iter_seq_info task_file_seq_info = { |
| <------>.seq_ops = &task_file_seq_ops, |
| <------>.init_seq_private = init_seq_pidns, |
| <------>.fini_seq_private = fini_seq_pidns, |
| <------>.seq_priv_size = sizeof(struct bpf_iter_seq_task_file_info), |
| }; |
| |
| static struct bpf_iter_reg task_file_reg_info = { |
| <------>.target = "task_file", |
| <------>.ctx_arg_info_size = 2, |
| <------>.ctx_arg_info = { |
| <------><------>{ offsetof(struct bpf_iter__task_file, task), |
| <------><------> PTR_TO_BTF_ID_OR_NULL }, |
| <------><------>{ offsetof(struct bpf_iter__task_file, file), |
| <------><------> PTR_TO_BTF_ID_OR_NULL }, |
| <------>}, |
| <------>.seq_info = &task_file_seq_info, |
| }; |
| |
| static int __init task_iter_init(void) |
| { |
| <------>int ret; |
| |
| <------>task_reg_info.ctx_arg_info[0].btf_id = btf_task_file_ids[0]; |
| <------>ret = bpf_iter_reg_target(&task_reg_info); |
| <------>if (ret) |
| <------><------>return ret; |
| |
| <------>task_file_reg_info.ctx_arg_info[0].btf_id = btf_task_file_ids[0]; |
| <------>task_file_reg_info.ctx_arg_info[1].btf_id = btf_task_file_ids[1]; |
| <------>return bpf_iter_reg_target(&task_file_reg_info); |
| } |
| late_initcall(task_iter_init); |
| |