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aya,int-test: revamp MapInfo be more friendly with older kernels
Adds detection for whether a field is available in `MapInfo`: - For `map_type()`, we treturn the `bpf_map_type` enum instead of the integer representation. - For fields that can't be zero, we return `Option<NonZero*>` type. - For `name_as_str()`, it now uses the feature probe `bpf_name()` to detect if field is available. Although the feature probe checks for program name, it can also be used for map name since they were both introduced in the same commit.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,173 @@ | ||
| //! Metadata information about an eBPF map. | ||
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|
||
| use std::{ | ||
| ffi::CString, | ||
| num::NonZeroU32, | ||
| os::fd::{AsFd as _, BorrowedFd}, | ||
| path::Path, | ||
| }; | ||
|
|
||
| use aya_obj::generated::{bpf_map_info, bpf_map_type}; | ||
|
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| use super::{MapError, MapFd}; | ||
| use crate::{ | ||
| sys::{ | ||
| bpf_get_object, bpf_map_get_fd_by_id, bpf_map_get_info_by_fd, iter_map_ids, SyscallError, | ||
| }, | ||
| util::bytes_of_bpf_name, | ||
| FEATURES, | ||
| }; | ||
|
|
||
| /// Provides information about a loaded map, like name, id and size. | ||
| #[doc(alias = "bpf_map_info")] | ||
| #[derive(Debug)] | ||
| pub struct MapInfo(pub(crate) bpf_map_info); | ||
|
|
||
| impl MapInfo { | ||
| pub(crate) fn new_from_fd(fd: BorrowedFd<'_>) -> Result<Self, MapError> { | ||
| let info = bpf_map_get_info_by_fd(fd.as_fd())?; | ||
| Ok(Self(info)) | ||
| } | ||
|
|
||
| /// Loads map info from a map ID. | ||
| /// | ||
| /// Uses kernel v4.13 features. | ||
| pub fn from_id(id: u32) -> Result<Self, MapError> { | ||
| bpf_map_get_fd_by_id(id) | ||
| .map_err(MapError::from) | ||
| .and_then(|fd| Self::new_from_fd(fd.as_fd())) | ||
| } | ||
|
|
||
| /// The map type as defined by the linux kernel enum [`bpf_map_type`]. | ||
| /// | ||
| /// Introduced in kernel v4.13. | ||
| pub fn map_type(&self) -> bpf_map_type { | ||
| bpf_map_type::try_from(self.0.type_).unwrap_or(bpf_map_type::__MAX_BPF_MAP_TYPE) | ||
| } | ||
|
|
||
| /// The unique ID for this map. | ||
| /// | ||
| /// `None` is returned if the field is not available. | ||
| /// | ||
| /// Introduced in kernel v4.13. | ||
| pub fn id(&self) -> Option<NonZeroU32> { | ||
| NonZeroU32::new(self.0.id) | ||
| } | ||
|
|
||
| /// The key size for this map in bytes. | ||
| /// | ||
| /// `None` is returned if the field is not available. | ||
| /// | ||
| /// Introduced in kernel v4.13. | ||
| pub fn key_size(&self) -> Option<NonZeroU32> { | ||
| NonZeroU32::new(self.0.key_size) | ||
| } | ||
|
|
||
| /// The value size for this map in bytes. | ||
| /// | ||
| /// `None` is returned if the field is not available. | ||
| /// | ||
| /// Introduced in kernel v4.13. | ||
| pub fn value_size(&self) -> Option<NonZeroU32> { | ||
| NonZeroU32::new(self.0.value_size) | ||
| } | ||
|
|
||
| /// The maximum number of entries in this map. | ||
| /// | ||
| /// `None` is returned if the field is not available. | ||
| /// | ||
| /// Introduced in kernel v4.13. | ||
| pub fn max_entries(&self) -> Option<NonZeroU32> { | ||
| NonZeroU32::new(self.0.max_entries) | ||
| } | ||
|
|
||
| /// The flags used in loading this map. | ||
| /// | ||
| /// Introduced in kernel v4.13. | ||
| pub fn map_flags(&self) -> u32 { | ||
| self.0.map_flags | ||
| } | ||
|
|
||
| /// The name of the map, limited to 16 bytes. | ||
| /// | ||
| /// Introduced in kernel v4.15. | ||
| pub fn name(&self) -> &[u8] { | ||
| bytes_of_bpf_name(&self.0.name) | ||
| } | ||
|
|
||
| /// The name of the map as a &str. | ||
| /// | ||
| /// `None` is returned if the name was not valid unicode or if field is not available. | ||
| /// | ||
| /// Introduced in kernel v4.15. | ||
| pub fn name_as_str(&self) -> Option<&str> { | ||
| let name = std::str::from_utf8(self.name()).ok(); | ||
| if let Some(name_str) = name { | ||
| // Char in program name was introduced in the same commit as map name | ||
| if FEATURES.bpf_name() || !name_str.is_empty() { | ||
| return name; | ||
| } | ||
| } | ||
| None | ||
| } | ||
|
|
||
| /// Returns a file descriptor referencing the map. | ||
| /// | ||
| /// The returned file descriptor can be closed at any time and doing so does | ||
| /// not influence the life cycle of the map. | ||
| /// | ||
| /// Uses kernel v4.13 features. | ||
| pub fn fd(&self) -> Result<MapFd, MapError> { | ||
| let Self(info) = self; | ||
| let fd = bpf_map_get_fd_by_id(info.id)?; | ||
| Ok(MapFd::from_fd(fd)) | ||
| } | ||
|
|
||
| /// Loads a map from a pinned path in bpffs. | ||
| /// | ||
| /// Uses kernel v4.4 and v4.13 features. | ||
| pub fn from_pin<P: AsRef<Path>>(path: P) -> Result<Self, MapError> { | ||
| use std::os::unix::ffi::OsStrExt as _; | ||
|
|
||
| // TODO: avoid this unwrap by adding a new error variant. | ||
| let path_string = CString::new(path.as_ref().as_os_str().as_bytes()).unwrap(); | ||
| let fd = bpf_get_object(&path_string).map_err(|(_, io_error)| SyscallError { | ||
| call: "BPF_OBJ_GET", | ||
| io_error, | ||
| })?; | ||
|
|
||
| Self::new_from_fd(fd.as_fd()) | ||
| } | ||
| } | ||
|
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||
| /// Returns an iterator over all loaded bpf maps. | ||
| /// | ||
| /// This differs from [`crate::Ebpf::maps`] since it will return all maps | ||
| /// listed on the host system and not only maps for a specific [`crate::Ebpf`] instance. | ||
| /// | ||
| /// Uses kernel v4.13 features. | ||
| /// | ||
| /// # Example | ||
| /// ``` | ||
| /// # use aya::maps::loaded_maps; | ||
| /// | ||
| /// for m in loaded_maps() { | ||
| /// match m { | ||
| /// Ok(map) => println!("{:?}", map.name_as_str()), | ||
| /// Err(e) => println!("Error iterating maps: {:?}", e), | ||
| /// } | ||
| /// } | ||
| /// ``` | ||
| /// | ||
| /// # Errors | ||
| /// | ||
| /// Returns [`MapError::SyscallError`] if any of the syscalls required to either get | ||
| /// next map id, get the map fd, or the [`MapInfo`] fail. In cases where | ||
| /// iteration can't be performed, for example the caller does not have the necessary privileges, | ||
| /// a single item will be yielded containing the error that occurred. | ||
| pub fn loaded_maps() -> impl Iterator<Item = Result<MapInfo, MapError>> { | ||
| iter_map_ids().map(|id| { | ||
| let id = id?; | ||
| MapInfo::from_id(id) | ||
| }) | ||
| } |
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