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

Source file repositories/reference/linux-study-clean/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
Extension
.c
Size
3311 bytes
Lines
118
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct core_reloc_kernel_output {
	int valid[10];
	/* we have test_progs[-flavor], so cut flavor part */
	char comm[sizeof("test_progs")];
	int comm_len;
	bool local_task_struct_matches;
};

struct task_struct {
	int pid;
	int tgid;
	char comm[16];
	struct task_struct *group_leader;
};

struct mm_struct___wrong {
    int abc_whatever_should_not_exist;
};

struct task_struct___local {
    int pid;
    struct mm_struct___wrong *mm;
};

#define CORE_READ(dst, src) bpf_core_read(dst, sizeof(*(dst)), src)

SEC("raw_tracepoint/sys_enter")
int test_core_kernel(void *ctx)
{
	/* Support for the BPF_TYPE_MATCHES argument to the
	 * __builtin_preserve_type_info builtin was added at some point during
	 * development of clang 15 and it's what we require for this test.
	 */
#if __has_builtin(__builtin_preserve_type_info) && __clang_major__ >= 15
	struct task_struct *task = (void *)bpf_get_current_task();
	struct core_reloc_kernel_output *out = (void *)&data.out;
	uint64_t pid_tgid = bpf_get_current_pid_tgid();
	int32_t real_tgid = (int32_t)pid_tgid;
	int pid, tgid;

	if (data.my_pid_tgid != pid_tgid)
		return 0;

	if (CORE_READ(&pid, &task->pid) ||
	    CORE_READ(&tgid, &task->tgid))
		return 1;

	/* validate pid + tgid matches */
	out->valid[0] = (((uint64_t)pid << 32) | tgid) == pid_tgid;

	/* test variadic BPF_CORE_READ macros */
	out->valid[1] = BPF_CORE_READ(task,
				      tgid) == real_tgid;
	out->valid[2] = BPF_CORE_READ(task,
				      group_leader,
				      tgid) == real_tgid;
	out->valid[3] = BPF_CORE_READ(task,
				      group_leader, group_leader,
				      tgid) == real_tgid;
	out->valid[4] = BPF_CORE_READ(task,
				      group_leader, group_leader, group_leader,
				      tgid) == real_tgid;
	out->valid[5] = BPF_CORE_READ(task,
				      group_leader, group_leader, group_leader,
				      group_leader,
				      tgid) == real_tgid;
	out->valid[6] = BPF_CORE_READ(task,
				      group_leader, group_leader, group_leader,
				      group_leader, group_leader,
				      tgid) == real_tgid;
	out->valid[7] = BPF_CORE_READ(task,
				      group_leader, group_leader, group_leader,
				      group_leader, group_leader, group_leader,
				      tgid) == real_tgid;
	out->valid[8] = BPF_CORE_READ(task,
				      group_leader, group_leader, group_leader,
				      group_leader, group_leader, group_leader,
				      group_leader,
				      tgid) == real_tgid;
	out->valid[9] = BPF_CORE_READ(task,
				      group_leader, group_leader, group_leader,
				      group_leader, group_leader, group_leader,
				      group_leader, group_leader,
				      tgid) == real_tgid;

	/* test BPF_CORE_READ_STR_INTO() returns correct code and contents */
	out->comm_len = BPF_CORE_READ_STR_INTO(
		&out->comm, task,
		group_leader, group_leader, group_leader, group_leader,
		group_leader, group_leader, group_leader, group_leader,

Annotation

Implementation Notes