1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2020 Facebook */
3
4 #include "vmlinux.h"
5 #include <bpf/bpf_helpers.h>
6 #include <bpf/bpf_core_read.h>
7 #include <bpf/bpf_tracing.h>
8
9 char _license[] SEC("license") = "GPL";
10
11 struct bpf_testmod_test_read_ctx {
12 /* field order is mixed up */
13 size_t len;
14 char *buf;
15 loff_t off;
16 } __attribute__((preserve_access_index));
17
18 struct {
19 char in[256];
20 char out[256];
21 bool skip;
22 uint64_t my_pid_tgid;
23 } data = {};
24
25 struct core_reloc_module_output {
26 long long len;
27 long long off;
28 int read_ctx_sz;
29 bool read_ctx_exists;
30 bool buf_exists;
31 bool len_exists;
32 bool off_exists;
33 /* we have test_progs[-flavor], so cut flavor part */
34 char comm[sizeof("test_progs")];
35 int comm_len;
36 };
37
38 SEC("raw_tp/bpf_testmod_test_read")
BPF_PROG(test_core_module_probed,struct task_struct * task,struct bpf_testmod_test_read_ctx * read_ctx)39 int BPF_PROG(test_core_module_probed,
40 struct task_struct *task,
41 struct bpf_testmod_test_read_ctx *read_ctx)
42 {
43 #if __has_builtin(__builtin_preserve_enum_value)
44 struct core_reloc_module_output *out = (void *)&data.out;
45 __u64 pid_tgid = bpf_get_current_pid_tgid();
46 __u32 real_tgid = (__u32)(pid_tgid >> 32);
47 __u32 real_pid = (__u32)pid_tgid;
48
49 if (data.my_pid_tgid != pid_tgid)
50 return 0;
51
52 if (BPF_CORE_READ(task, pid) != real_pid || BPF_CORE_READ(task, tgid) != real_tgid)
53 return 0;
54
55 out->len = BPF_CORE_READ(read_ctx, len);
56 out->off = BPF_CORE_READ(read_ctx, off);
57
58 out->read_ctx_sz = bpf_core_type_size(struct bpf_testmod_test_read_ctx);
59 out->read_ctx_exists = bpf_core_type_exists(struct bpf_testmod_test_read_ctx);
60 out->buf_exists = bpf_core_field_exists(read_ctx->buf);
61 out->off_exists = bpf_core_field_exists(read_ctx->off);
62 out->len_exists = bpf_core_field_exists(read_ctx->len);
63
64 out->comm_len = BPF_CORE_READ_STR_INTO(&out->comm, task, comm);
65 #else
66 data.skip = true;
67 #endif
68
69 return 0;
70 }
71
72 SEC("tp_btf/bpf_testmod_test_read")
BPF_PROG(test_core_module_direct,struct task_struct * task,struct bpf_testmod_test_read_ctx * read_ctx)73 int BPF_PROG(test_core_module_direct,
74 struct task_struct *task,
75 struct bpf_testmod_test_read_ctx *read_ctx)
76 {
77 #if __has_builtin(__builtin_preserve_enum_value)
78 struct core_reloc_module_output *out = (void *)&data.out;
79 __u64 pid_tgid = bpf_get_current_pid_tgid();
80 __u32 real_tgid = (__u32)(pid_tgid >> 32);
81 __u32 real_pid = (__u32)pid_tgid;
82
83 if (data.my_pid_tgid != pid_tgid)
84 return 0;
85
86 if (task->pid != real_pid || task->tgid != real_tgid)
87 return 0;
88
89 out->len = read_ctx->len;
90 out->off = read_ctx->off;
91
92 out->read_ctx_sz = bpf_core_type_size(struct bpf_testmod_test_read_ctx);
93 out->read_ctx_exists = bpf_core_type_exists(struct bpf_testmod_test_read_ctx);
94 out->buf_exists = bpf_core_field_exists(read_ctx->buf);
95 out->off_exists = bpf_core_field_exists(read_ctx->off);
96 out->len_exists = bpf_core_field_exists(read_ctx->len);
97
98 out->comm_len = BPF_CORE_READ_STR_INTO(&out->comm, task, comm);
99 #else
100 data.skip = true;
101 #endif
102
103 return 0;
104 }
105