1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2019 Facebook
3
4#include <linux/bpf.h>
5#include <stdint.h>
6#include <stdbool.h>
7#include <bpf/bpf_helpers.h>
8#include <bpf/bpf_core_read.h>
9
10char _license[] SEC("license") = "GPL";
11
12struct {
13	char in[256];
14	char out[256];
15	bool skip;
16	uint64_t my_pid_tgid;
17} data = {};
18
19struct core_reloc_kernel_output {
20	int valid[10];
21	/* we have test_progs[-flavor], so cut flavor part */
22	char comm[sizeof("test_progs")];
23	int comm_len;
24	bool local_task_struct_matches;
25};
26
27struct task_struct {
28	int pid;
29	int tgid;
30	char comm[16];
31	struct task_struct *group_leader;
32};
33
34struct mm_struct___wrong {
35    int abc_whatever_should_not_exist;
36};
37
38struct task_struct___local {
39    int pid;
40    struct mm_struct___wrong *mm;
41};
42
43#define CORE_READ(dst, src) bpf_core_read(dst, sizeof(*(dst)), src)
44
45SEC("raw_tracepoint/sys_enter")
46int test_core_kernel(void *ctx)
47{
48	/* Support for the BPF_TYPE_MATCHES argument to the
49	 * __builtin_preserve_type_info builtin was added at some point during
50	 * development of clang 15 and it's what we require for this test.
51	 */
52#if __has_builtin(__builtin_preserve_type_info) && __clang_major__ >= 15
53	struct task_struct *task = (void *)bpf_get_current_task();
54	struct core_reloc_kernel_output *out = (void *)&data.out;
55	uint64_t pid_tgid = bpf_get_current_pid_tgid();
56	int32_t real_tgid = (int32_t)pid_tgid;
57	int pid, tgid;
58
59	if (data.my_pid_tgid != pid_tgid)
60		return 0;
61
62	if (CORE_READ(&pid, &task->pid) ||
63	    CORE_READ(&tgid, &task->tgid))
64		return 1;
65
66	/* validate pid + tgid matches */
67	out->valid[0] = (((uint64_t)pid << 32) | tgid) == pid_tgid;
68
69	/* test variadic BPF_CORE_READ macros */
70	out->valid[1] = BPF_CORE_READ(task,
71				      tgid) == real_tgid;
72	out->valid[2] = BPF_CORE_READ(task,
73				      group_leader,
74				      tgid) == real_tgid;
75	out->valid[3] = BPF_CORE_READ(task,
76				      group_leader, group_leader,
77				      tgid) == real_tgid;
78	out->valid[4] = BPF_CORE_READ(task,
79				      group_leader, group_leader, group_leader,
80				      tgid) == real_tgid;
81	out->valid[5] = BPF_CORE_READ(task,
82				      group_leader, group_leader, group_leader,
83				      group_leader,
84				      tgid) == real_tgid;
85	out->valid[6] = BPF_CORE_READ(task,
86				      group_leader, group_leader, group_leader,
87				      group_leader, group_leader,
88				      tgid) == real_tgid;
89	out->valid[7] = BPF_CORE_READ(task,
90				      group_leader, group_leader, group_leader,
91				      group_leader, group_leader, group_leader,
92				      tgid) == real_tgid;
93	out->valid[8] = BPF_CORE_READ(task,
94				      group_leader, group_leader, group_leader,
95				      group_leader, group_leader, group_leader,
96				      group_leader,
97				      tgid) == real_tgid;
98	out->valid[9] = BPF_CORE_READ(task,
99				      group_leader, group_leader, group_leader,
100				      group_leader, group_leader, group_leader,
101				      group_leader, group_leader,
102				      tgid) == real_tgid;
103
104	/* test BPF_CORE_READ_STR_INTO() returns correct code and contents */
105	out->comm_len = BPF_CORE_READ_STR_INTO(
106		&out->comm, task,
107		group_leader, group_leader, group_leader, group_leader,
108		group_leader, group_leader, group_leader, group_leader,
109		comm);
110
111	out->local_task_struct_matches = bpf_core_type_matches(struct task_struct___local);
112#else
113	data.skip = true;
114#endif
115	return 0;
116}
117
118