1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* Copyright (c) 2020 Facebook */ |
3 | #include "bpf_iter.h" |
4 | #include <bpf/bpf_helpers.h> |
5 | #include <bpf/bpf_tracing.h> |
6 | |
7 | char _license[] SEC("license" ) = "GPL" ; |
8 | |
9 | uint32_t tid = 0; |
10 | int num_unknown_tid = 0; |
11 | int num_known_tid = 0; |
12 | |
13 | SEC("iter/task" ) |
14 | int dump_task(struct bpf_iter__task *ctx) |
15 | { |
16 | struct seq_file *seq = ctx->meta->seq; |
17 | struct task_struct *task = ctx->task; |
18 | static char info[] = " === END ===" ; |
19 | |
20 | if (task == (void *)0) { |
21 | BPF_SEQ_PRINTF(seq, "%s\n" , info); |
22 | return 0; |
23 | } |
24 | |
25 | if (task->pid != (pid_t)tid) |
26 | num_unknown_tid++; |
27 | else |
28 | num_known_tid++; |
29 | |
30 | if (ctx->meta->seq_num == 0) |
31 | BPF_SEQ_PRINTF(seq, " tgid gid\n" ); |
32 | |
33 | BPF_SEQ_PRINTF(seq, "%8d %8d\n" , task->tgid, task->pid); |
34 | return 0; |
35 | } |
36 | |
37 | int num_expected_failure_copy_from_user_task = 0; |
38 | int num_success_copy_from_user_task = 0; |
39 | |
40 | SEC("iter.s/task" ) |
41 | int dump_task_sleepable(struct bpf_iter__task *ctx) |
42 | { |
43 | struct seq_file *seq = ctx->meta->seq; |
44 | struct task_struct *task = ctx->task; |
45 | static const char info[] = " === END ===" ; |
46 | struct pt_regs *regs; |
47 | void *ptr; |
48 | uint32_t user_data = 0; |
49 | int ret; |
50 | |
51 | if (task == (void *)0) { |
52 | BPF_SEQ_PRINTF(seq, "%s\n" , info); |
53 | return 0; |
54 | } |
55 | |
56 | /* Read an invalid pointer and ensure we get an error */ |
57 | ptr = NULL; |
58 | ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0); |
59 | if (ret) { |
60 | ++num_expected_failure_copy_from_user_task; |
61 | } else { |
62 | BPF_SEQ_PRINTF(seq, "%s\n" , info); |
63 | return 0; |
64 | } |
65 | |
66 | /* Try to read the contents of the task's instruction pointer from the |
67 | * remote task's address space. |
68 | */ |
69 | regs = (struct pt_regs *)bpf_task_pt_regs(task); |
70 | if (regs == (void *)0) { |
71 | BPF_SEQ_PRINTF(seq, "%s\n" , info); |
72 | return 0; |
73 | } |
74 | ptr = (void *)PT_REGS_IP(regs); |
75 | |
76 | ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0); |
77 | if (ret) { |
78 | BPF_SEQ_PRINTF(seq, "%s\n" , info); |
79 | return 0; |
80 | } |
81 | ++num_success_copy_from_user_task; |
82 | |
83 | if (ctx->meta->seq_num == 0) |
84 | BPF_SEQ_PRINTF(seq, " tgid gid data\n" ); |
85 | |
86 | BPF_SEQ_PRINTF(seq, "%8d %8d %8d\n" , task->tgid, task->pid, user_data); |
87 | return 0; |
88 | } |
89 | |