counter_config/
config_lib_rust_config_lib_source.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
use fidl::unpersist;
use fidl_cf_sc_internal_counterconfig::Config as FidlConfig;
use fuchsia_inspect::Node;
use fuchsia_runtime::{take_startup_handle, HandleInfo, HandleType};
#[derive(Debug)]
pub struct Config {
    pub routed_config: bool,
    pub starting_value: u32,
}
impl Config {
    pub fn take_from_startup_handle() -> Self {
        let config_vmo: zx::Vmo =
            take_startup_handle(HandleInfo::new(HandleType::ComponentConfigVmo, 0))
                .expect("Config VMO handle must be provided and cannot already have been taken.")
                .into();
        let config_size =
            config_vmo.get_content_size().expect("must be able to read config vmo content size");
        assert_ne!(config_size, 0, "config vmo must be non-empty");
        let config_bytes =
            config_vmo.read_to_vec(0, config_size).expect("must be able to read config vmo");
        let checksum_length = u16::from_le_bytes([config_bytes[0], config_bytes[1]]) as usize;
        let fidl_start = 2 + checksum_length;
        let observed_checksum = &config_bytes[2..fidl_start];
        let expected_checksum = vec![
            0x8c, 0x34, 0x33, 0xab, 0x56, 0x0b, 0xac, 0xac, 0x14, 0x25, 0x4f, 0x40, 0xdf, 0x8e,
            0x3d, 0x6a, 0x6d, 0x4d, 0xbb, 0x21, 0x16, 0xdf, 0x2b, 0x49, 0x49, 0xc0, 0x6a, 0x44,
            0x08, 0x94, 0x27, 0xae,
        ];
        assert_eq!(
            observed_checksum, expected_checksum,
            "checksum from config VMO does not match expected checksum"
        );
        let fidl_config: FidlConfig = unpersist(&config_bytes[fidl_start..])
            .expect("must be able to parse bytes as config FIDL");
        Self {
            routed_config: fidl_config.routed_config,
            starting_value: fidl_config.starting_value,
        }
    }
    pub fn record_inspect(&self, inspector_node: &Node) {
        inspector_node.record_bool("routed_config", self.routed_config);
        inspector_node.record_uint("starting_value", self.starting_value as u64);
    }
}