static int probe_map_create()

in contrib/libbpf/src/libbpf_probes.c [274:387]

• 105 lines of code
• 46 McCabe index (conditional complexity)

static int probe_map_create(enum bpf_map_type map_type)
{
	LIBBPF_OPTS(bpf_map_create_opts, opts);
	int key_size, value_size, max_entries;
	__u32 btf_key_type_id = 0, btf_value_type_id = 0;
	int fd = -1, btf_fd = -1, fd_inner = -1, exp_err = 0, err = 0;

	key_size	= sizeof(__u32);
	value_size	= sizeof(__u32);
	max_entries	= 1;

	switch (map_type) {
	case BPF_MAP_TYPE_STACK_TRACE:
		value_size	= sizeof(__u64);
		break;
	case BPF_MAP_TYPE_LPM_TRIE:
		key_size	= sizeof(__u64);
		value_size	= sizeof(__u64);
		opts.map_flags	= BPF_F_NO_PREALLOC;
		break;
	case BPF_MAP_TYPE_CGROUP_STORAGE:
	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
		key_size	= sizeof(struct bpf_cgroup_storage_key);
		value_size	= sizeof(__u64);
		max_entries	= 0;
		break;
	case BPF_MAP_TYPE_QUEUE:
	case BPF_MAP_TYPE_STACK:
		key_size	= 0;
		break;
	case BPF_MAP_TYPE_SK_STORAGE:
	case BPF_MAP_TYPE_INODE_STORAGE:
	case BPF_MAP_TYPE_TASK_STORAGE:
	case BPF_MAP_TYPE_CGRP_STORAGE:
		btf_key_type_id = 1;
		btf_value_type_id = 3;
		value_size = 8;
		max_entries = 0;
		opts.map_flags = BPF_F_NO_PREALLOC;
		btf_fd = load_local_storage_btf();
		if (btf_fd < 0)
			return btf_fd;
		break;
	case BPF_MAP_TYPE_RINGBUF:
	case BPF_MAP_TYPE_USER_RINGBUF:
		key_size = 0;
		value_size = 0;
		max_entries = sysconf(_SC_PAGE_SIZE);
		break;
	case BPF_MAP_TYPE_STRUCT_OPS:
		/* we'll get -ENOTSUPP for invalid BTF type ID for struct_ops */
		opts.btf_vmlinux_value_type_id = 1;
		exp_err = -524; /* -ENOTSUPP */
		break;
	case BPF_MAP_TYPE_BLOOM_FILTER:
		key_size = 0;
		max_entries = 1;
		break;
	case BPF_MAP_TYPE_HASH:
	case BPF_MAP_TYPE_ARRAY:
	case BPF_MAP_TYPE_PROG_ARRAY:
	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
	case BPF_MAP_TYPE_PERCPU_HASH:
	case BPF_MAP_TYPE_PERCPU_ARRAY:
	case BPF_MAP_TYPE_CGROUP_ARRAY:
	case BPF_MAP_TYPE_LRU_HASH:
	case BPF_MAP_TYPE_LRU_PERCPU_HASH:
	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
	case BPF_MAP_TYPE_HASH_OF_MAPS:
	case BPF_MAP_TYPE_DEVMAP:
	case BPF_MAP_TYPE_DEVMAP_HASH:
	case BPF_MAP_TYPE_SOCKMAP:
	case BPF_MAP_TYPE_CPUMAP:
	case BPF_MAP_TYPE_XSKMAP:
	case BPF_MAP_TYPE_SOCKHASH:
	case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
		break;
	case BPF_MAP_TYPE_UNSPEC:
	default:
		return -EOPNOTSUPP;
	}

	if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
	    map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
		fd_inner = bpf_map_create(BPF_MAP_TYPE_HASH, NULL,
					  sizeof(__u32), sizeof(__u32), 1, NULL);
		if (fd_inner < 0)
			goto cleanup;

		opts.inner_map_fd = fd_inner;
	}

	if (btf_fd >= 0) {
		opts.btf_fd = btf_fd;
		opts.btf_key_type_id = btf_key_type_id;
		opts.btf_value_type_id = btf_value_type_id;
	}

	fd = bpf_map_create(map_type, NULL, key_size, value_size, max_entries, &opts);
	err = -errno;

cleanup:
	if (fd >= 0)
		close(fd);
	if (fd_inner >= 0)
		close(fd_inner);
	if (btf_fd >= 0)
		close(btf_fd);

	if (exp_err)
		return fd < 0 && err == exp_err ? 1 : 0;
	else
		return fd >= 0 ? 1 : 0;
}