1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2020 Facebook */
4 #include <linux/init.h>
5 #include <linux/namei.h>
6 #include <linux/pid_namespace.h>
8 #include <linux/fdtable.h>
9 #include <linux/filter.h>
10 #include <linux/btf_ids.h>
12 struct bpf_iter_seq_task_common {
13 struct pid_namespace *ns;
16 struct bpf_iter_seq_task_info {
17 /* The first field must be struct bpf_iter_seq_task_common.
18 * this is assumed by {init, fini}_seq_pidns() callback functions.
20 struct bpf_iter_seq_task_common common;
24 static struct task_struct *task_seq_get_next(struct pid_namespace *ns,
26 bool skip_if_dup_files)
28 struct task_struct *task = NULL;
33 pid = find_ge_pid(*tid, ns);
35 *tid = pid_nr_ns(pid, ns);
36 task = get_pid_task(pid, PIDTYPE_PID);
40 } else if (skip_if_dup_files && !thread_group_leader(task) &&
41 task->files == task->group_leader->files) {
42 put_task_struct(task);
53 static void *task_seq_start(struct seq_file *seq, loff_t *pos)
55 struct bpf_iter_seq_task_info *info = seq->private;
56 struct task_struct *task;
58 task = task_seq_get_next(info->common.ns, &info->tid, false);
67 static void *task_seq_next(struct seq_file *seq, void *v, loff_t *pos)
69 struct bpf_iter_seq_task_info *info = seq->private;
70 struct task_struct *task;
74 put_task_struct((struct task_struct *)v);
75 task = task_seq_get_next(info->common.ns, &info->tid, false);
82 struct bpf_iter__task {
83 __bpf_md_ptr(struct bpf_iter_meta *, meta);
84 __bpf_md_ptr(struct task_struct *, task);
87 DEFINE_BPF_ITER_FUNC(task, struct bpf_iter_meta *meta, struct task_struct *task)
89 static int __task_seq_show(struct seq_file *seq, struct task_struct *task,
92 struct bpf_iter_meta meta;
93 struct bpf_iter__task ctx;
94 struct bpf_prog *prog;
97 prog = bpf_iter_get_info(&meta, in_stop);
104 return bpf_iter_run_prog(prog, &ctx);
107 static int task_seq_show(struct seq_file *seq, void *v)
109 return __task_seq_show(seq, v, false);
112 static void task_seq_stop(struct seq_file *seq, void *v)
115 (void)__task_seq_show(seq, v, true);
117 put_task_struct((struct task_struct *)v);
120 static const struct seq_operations task_seq_ops = {
121 .start = task_seq_start,
122 .next = task_seq_next,
123 .stop = task_seq_stop,
124 .show = task_seq_show,
127 struct bpf_iter_seq_task_file_info {
128 /* The first field must be struct bpf_iter_seq_task_common.
129 * this is assumed by {init, fini}_seq_pidns() callback functions.
131 struct bpf_iter_seq_task_common common;
132 struct task_struct *task;
138 task_file_seq_get_next(struct bpf_iter_seq_task_file_info *info)
140 struct pid_namespace *ns = info->common.ns;
141 u32 curr_tid = info->tid;
142 struct task_struct *curr_task;
143 unsigned int curr_fd = info->fd;
145 /* If this function returns a non-NULL file object,
146 * it held a reference to the task/file.
147 * Otherwise, it does not hold any reference.
151 curr_task = info->task;
154 curr_task = task_seq_get_next(ns, &curr_tid, true);
157 info->tid = curr_tid;
161 /* set info->task and info->tid */
162 info->task = curr_task;
163 if (curr_tid == info->tid) {
166 info->tid = curr_tid;
174 f = task_lookup_next_fd_rcu(curr_task, &curr_fd);
177 if (!get_file_rcu(f))
186 /* the current task is done, go to the next task */
188 put_task_struct(curr_task);
191 curr_tid = ++(info->tid);
195 static void *task_file_seq_start(struct seq_file *seq, loff_t *pos)
197 struct bpf_iter_seq_task_file_info *info = seq->private;
201 file = task_file_seq_get_next(info);
202 if (file && *pos == 0)
208 static void *task_file_seq_next(struct seq_file *seq, void *v, loff_t *pos)
210 struct bpf_iter_seq_task_file_info *info = seq->private;
214 fput((struct file *)v);
215 return task_file_seq_get_next(info);
218 struct bpf_iter__task_file {
219 __bpf_md_ptr(struct bpf_iter_meta *, meta);
220 __bpf_md_ptr(struct task_struct *, task);
222 __bpf_md_ptr(struct file *, file);
225 DEFINE_BPF_ITER_FUNC(task_file, struct bpf_iter_meta *meta,
226 struct task_struct *task, u32 fd,
229 static int __task_file_seq_show(struct seq_file *seq, struct file *file,
232 struct bpf_iter_seq_task_file_info *info = seq->private;
233 struct bpf_iter__task_file ctx;
234 struct bpf_iter_meta meta;
235 struct bpf_prog *prog;
238 prog = bpf_iter_get_info(&meta, in_stop);
243 ctx.task = info->task;
246 return bpf_iter_run_prog(prog, &ctx);
249 static int task_file_seq_show(struct seq_file *seq, void *v)
251 return __task_file_seq_show(seq, v, false);
254 static void task_file_seq_stop(struct seq_file *seq, void *v)
256 struct bpf_iter_seq_task_file_info *info = seq->private;
259 (void)__task_file_seq_show(seq, v, true);
261 fput((struct file *)v);
262 put_task_struct(info->task);
267 static int init_seq_pidns(void *priv_data, struct bpf_iter_aux_info *aux)
269 struct bpf_iter_seq_task_common *common = priv_data;
271 common->ns = get_pid_ns(task_active_pid_ns(current));
275 static void fini_seq_pidns(void *priv_data)
277 struct bpf_iter_seq_task_common *common = priv_data;
279 put_pid_ns(common->ns);
282 static const struct seq_operations task_file_seq_ops = {
283 .start = task_file_seq_start,
284 .next = task_file_seq_next,
285 .stop = task_file_seq_stop,
286 .show = task_file_seq_show,
289 BTF_ID_LIST(btf_task_file_ids)
290 BTF_ID(struct, task_struct)
293 static const struct bpf_iter_seq_info task_seq_info = {
294 .seq_ops = &task_seq_ops,
295 .init_seq_private = init_seq_pidns,
296 .fini_seq_private = fini_seq_pidns,
297 .seq_priv_size = sizeof(struct bpf_iter_seq_task_info),
300 static struct bpf_iter_reg task_reg_info = {
302 .feature = BPF_ITER_RESCHED,
303 .ctx_arg_info_size = 1,
305 { offsetof(struct bpf_iter__task, task),
306 PTR_TO_BTF_ID_OR_NULL },
308 .seq_info = &task_seq_info,
311 static const struct bpf_iter_seq_info task_file_seq_info = {
312 .seq_ops = &task_file_seq_ops,
313 .init_seq_private = init_seq_pidns,
314 .fini_seq_private = fini_seq_pidns,
315 .seq_priv_size = sizeof(struct bpf_iter_seq_task_file_info),
318 static struct bpf_iter_reg task_file_reg_info = {
319 .target = "task_file",
320 .feature = BPF_ITER_RESCHED,
321 .ctx_arg_info_size = 2,
323 { offsetof(struct bpf_iter__task_file, task),
324 PTR_TO_BTF_ID_OR_NULL },
325 { offsetof(struct bpf_iter__task_file, file),
326 PTR_TO_BTF_ID_OR_NULL },
328 .seq_info = &task_file_seq_info,
331 static int __init task_iter_init(void)
335 task_reg_info.ctx_arg_info[0].btf_id = btf_task_file_ids[0];
336 ret = bpf_iter_reg_target(&task_reg_info);
340 task_file_reg_info.ctx_arg_info[0].btf_id = btf_task_file_ids[0];
341 task_file_reg_info.ctx_arg_info[1].btf_id = btf_task_file_ids[1];
342 return bpf_iter_reg_target(&task_file_reg_info);
344 late_initcall(task_iter_init);