tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c

   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
  10 char _license[] SEC("license") = "GPL";
  11
  12 struct {
  13         char in[256];
  14         char out[256];
  15         bool skip;
  16         uint64_t my_pid_tgid;
  17 } data = {};
  18
  19 struct 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
  27 struct task_struct {
  28         int pid;
  29         int tgid;
  30         char comm[16];
  31         struct task_struct *group_leader;
  32 };
  33
  34 struct mm_struct___wrong {
  35     int abc_whatever_should_not_exist;
  36 };
  37
  38 struct 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
  45 SEC("raw_tracepoint/sys_enter")
  46 int 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         uint32_t real_tgid = (uint32_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