system_updater_config/
config_lib_rust_config_lib_source.rs

1use fidl::unpersist;
2use fidl_cf_sc_internal_systemupdaterconfig::Config as FidlConfig;
3use fuchsia_inspect::Node;
4use fuchsia_runtime::{take_startup_handle, HandleInfo, HandleType};
5use std::convert::TryInto;
6const EXPECTED_CHECKSUM: &[u8] = &[
7    0x29, 0x13, 0x7c, 0x37, 0xe7, 0x60, 0x88, 0xbb, 0x2b, 0x64, 0x9a, 0xfa, 0xe2, 0xf5, 0x35, 0xe5,
8    0x1e, 0x5f, 0x60, 0x49, 0xd7, 0x85, 0xaa, 0x40, 0x84, 0x49, 0xe8, 0x09, 0xf1, 0xe6, 0x1f, 0x39,
9];
10#[derive(Debug)]
11pub struct Config {
12    pub concurrent_package_resolves: u16,
13}
14impl Config {
15    #[doc = r" Take the config startup handle and parse its contents."]
16    #[doc = r""]
17    #[doc = r" # Panics"]
18    #[doc = r""]
19    #[doc = r" If the config startup handle was already taken or if it is not valid."]
20    pub fn take_from_startup_handle() -> Self {
21        let handle_info = HandleInfo::new(HandleType::ComponentConfigVmo, 0);
22        let config_vmo: zx::Vmo =
23            take_startup_handle(handle_info).expect("Config VMO handle must be present.").into();
24        Self::from_vmo(&config_vmo).expect("Config VMO handle must be valid.")
25    }
26    #[doc = r" Parse `Self` from `vmo`."]
27    pub fn from_vmo(vmo: &zx::Vmo) -> Result<Self, Error> {
28        let config_size = vmo.get_content_size().map_err(Error::GettingContentSize)?;
29        let config_bytes = vmo.read_to_vec(0, config_size).map_err(Error::ReadingConfigBytes)?;
30        Self::from_bytes(&config_bytes)
31    }
32    #[doc = r" Parse `Self` from `bytes`."]
33    pub fn from_bytes(bytes: &[u8]) -> Result<Self, Error> {
34        let (checksum_len_bytes, bytes) = bytes.split_at_checked(2).ok_or(Error::TooFewBytes)?;
35        let checksum_len_bytes: [u8; 2] =
36            checksum_len_bytes.try_into().expect("previous call guaranteed 2 element slice");
37        let checksum_length = u16::from_le_bytes(checksum_len_bytes) as usize;
38        let (observed_checksum, bytes) =
39            bytes.split_at_checked(checksum_length).ok_or(Error::TooFewBytes)?;
40        if observed_checksum != EXPECTED_CHECKSUM {
41            return Err(Error::ChecksumMismatch { observed_checksum: observed_checksum.to_vec() });
42        }
43        let fidl_config: FidlConfig = unpersist(bytes).map_err(Error::Unpersist)?;
44        Ok(Self { concurrent_package_resolves: fidl_config.concurrent_package_resolves })
45    }
46    pub fn record_inspect(&self, inspector_node: &Node) {
47        inspector_node
48            .record_uint("concurrent_package_resolves", self.concurrent_package_resolves as u64);
49    }
50}
51#[derive(Debug)]
52pub enum Error {
53    #[doc = r" Failed to read the content size of the VMO."]
54    GettingContentSize(zx::Status),
55    #[doc = r" Failed to read the content of the VMO."]
56    ReadingConfigBytes(zx::Status),
57    #[doc = r" The VMO was too small for this config library."]
58    TooFewBytes,
59    #[doc = r" The VMO's config ABI checksum did not match this library's."]
60    ChecksumMismatch { observed_checksum: Vec<u8> },
61    #[doc = r" Failed to parse the non-checksum bytes of the VMO as this library's FIDL type."]
62    Unpersist(fidl::Error),
63}
64impl std::fmt::Display for Error {
65    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
66        match self {
67            Self::GettingContentSize(status) => {
68                write!(f, "Failed to get content size: {status}")
69            }
70            Self::ReadingConfigBytes(status) => {
71                write!(f, "Failed to read VMO content: {status}")
72            }
73            Self::TooFewBytes => {
74                write!(f, "VMO content is not large enough for this config library.")
75            }
76            Self::ChecksumMismatch { observed_checksum } => {
77                write!(
78                    f,
79                    "ABI checksum mismatch, expected {:?}, got {:?}",
80                    EXPECTED_CHECKSUM, observed_checksum,
81                )
82            }
83            Self::Unpersist(fidl_error) => {
84                write!(f, "Failed to parse contents of config VMO: {fidl_error}")
85            }
86        }
87    }
88}
89impl std::error::Error for Error {
90    #[allow(unused_parens, reason = "rustfmt errors without parens here")]
91    fn source(&self) -> Option<(&'_ (dyn std::error::Error + 'static))> {
92        match self {
93            Self::GettingContentSize(ref status) | Self::ReadingConfigBytes(ref status) => {
94                Some(status)
95            }
96            Self::TooFewBytes => None,
97            Self::ChecksumMismatch { .. } => None,
98            Self::Unpersist(ref fidl_error) => Some(fidl_error),
99        }
100    }
101    fn description(&self) -> &str {
102        match self {
103            Self::GettingContentSize(_) => "getting content size",
104            Self::ReadingConfigBytes(_) => "reading VMO contents",
105            Self::TooFewBytes => "VMO contents too small",
106            Self::ChecksumMismatch { .. } => "ABI checksum mismatch",
107            Self::Unpersist(_) => "FIDL parsing error",
108        }
109    }
110}
system_updater_config/config_lib_rust_config_lib_source.rs

system_updater_config/
config_lib_rust_config_lib_source.rs
