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 && task->tgid != task->pid &&
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);
160 /* set info->task and info->tid */
161 info->task = curr_task;
162 if (curr_tid == info->tid) {
165 info->tid = curr_tid;
173 f = task_lookup_next_fd_rcu(curr_task, &curr_fd);
176 if (!get_file_rcu(f))
185 /* the current task is done, go to the next task */
187 put_task_struct(curr_task);
190 curr_tid = ++(info->tid);
194 static void *task_file_seq_start(struct seq_file *seq, loff_t *pos)
196 struct bpf_iter_seq_task_file_info *info = seq->private;
200 file = task_file_seq_get_next(info);
201 if (file && *pos == 0)
207 static void *task_file_seq_next(struct seq_file *seq, void *v, loff_t *pos)
209 struct bpf_iter_seq_task_file_info *info = seq->private;
213 fput((struct file *)v);
214 return task_file_seq_get_next(info);
217 struct bpf_iter__task_file {
218 __bpf_md_ptr(struct bpf_iter_meta *, meta);
219 __bpf_md_ptr(struct task_struct *, task);
221 __bpf_md_ptr(struct file *, file);
224 DEFINE_BPF_ITER_FUNC(task_file, struct bpf_iter_meta *meta,
225 struct task_struct *task, u32 fd,
228 static int __task_file_seq_show(struct seq_file *seq, struct file *file,
231 struct bpf_iter_seq_task_file_info *info = seq->private;
232 struct bpf_iter__task_file ctx;
233 struct bpf_iter_meta meta;
234 struct bpf_prog *prog;
237 prog = bpf_iter_get_info(&meta, in_stop);
242 ctx.task = info->task;
245 return bpf_iter_run_prog(prog, &ctx);
248 static int task_file_seq_show(struct seq_file *seq, void *v)
250 return __task_file_seq_show(seq, v, false);
253 static void task_file_seq_stop(struct seq_file *seq, void *v)
255 struct bpf_iter_seq_task_file_info *info = seq->private;
258 (void)__task_file_seq_show(seq, v, true);
260 fput((struct file *)v);
261 put_task_struct(info->task);
266 static int init_seq_pidns(void *priv_data, struct bpf_iter_aux_info *aux)
268 struct bpf_iter_seq_task_common *common = priv_data;
270 common->ns = get_pid_ns(task_active_pid_ns(current));
274 static void fini_seq_pidns(void *priv_data)
276 struct bpf_iter_seq_task_common *common = priv_data;
278 put_pid_ns(common->ns);
281 static const struct seq_operations task_file_seq_ops = {
282 .start = task_file_seq_start,
283 .next = task_file_seq_next,
284 .stop = task_file_seq_stop,
285 .show = task_file_seq_show,
288 BTF_ID_LIST(btf_task_file_ids)
289 BTF_ID(struct, task_struct)
292 static const struct bpf_iter_seq_info task_seq_info = {
293 .seq_ops = &task_seq_ops,
294 .init_seq_private = init_seq_pidns,
295 .fini_seq_private = fini_seq_pidns,
296 .seq_priv_size = sizeof(struct bpf_iter_seq_task_info),
299 static struct bpf_iter_reg task_reg_info = {
301 .feature = BPF_ITER_RESCHED,
302 .ctx_arg_info_size = 1,
304 { offsetof(struct bpf_iter__task, task),
305 PTR_TO_BTF_ID_OR_NULL },
307 .seq_info = &task_seq_info,
310 static const struct bpf_iter_seq_info task_file_seq_info = {
311 .seq_ops = &task_file_seq_ops,
312 .init_seq_private = init_seq_pidns,
313 .fini_seq_private = fini_seq_pidns,
314 .seq_priv_size = sizeof(struct bpf_iter_seq_task_file_info),
317 static struct bpf_iter_reg task_file_reg_info = {
318 .target = "task_file",
319 .feature = BPF_ITER_RESCHED,
320 .ctx_arg_info_size = 2,
322 { offsetof(struct bpf_iter__task_file, task),
323 PTR_TO_BTF_ID_OR_NULL },
324 { offsetof(struct bpf_iter__task_file, file),
325 PTR_TO_BTF_ID_OR_NULL },
327 .seq_info = &task_file_seq_info,
330 static int __init task_iter_init(void)
334 task_reg_info.ctx_arg_info[0].btf_id = btf_task_file_ids[0];
335 ret = bpf_iter_reg_target(&task_reg_info);
339 task_file_reg_info.ctx_arg_info[0].btf_id = btf_task_file_ids[0];
340 task_file_reg_info.ctx_arg_info[1].btf_id = btf_task_file_ids[1];
341 return bpf_iter_reg_target(&task_file_reg_info);
343 late_initcall(task_iter_init);