address remaining notes

aya/src/maps/stack_trace.rs

@@ -1,7 +1,7 @@
 //! A hash map of kernel or user space stack traces.
 //!
 //! See [`StackTraceMap`] for documentation and examples.
-use std::{borrow::Borrow, collections::BTreeMap, fs, io, mem, path::Path, str::FromStr};
+use std::{borrow::Borrow, fs, io, mem, path::Path, str::FromStr};
 
 use crate::{
     maps::{IterableMap, MapData, MapError, MapIter, MapKeys},
@@ -162,16 +162,7 @@ impl<'a, T: Borrow<MapData>> IntoIterator for &'a StackTraceMap<T> {
 /// A resolver for symbols based on an address obtained from a stack trace.
 pub trait SymbolResolver {
     /// Resolve a symbol for a given address, if possible.
-    fn resolve_sym(&self, addr: u64) -> Option<String>;
-}
-
-/// The simplest resolver: a direct map from addresses to strings.
-pub type SimpleSymbolResolver = BTreeMap<u64, String>;
-
-impl SymbolResolver for SimpleSymbolResolver {
-    fn resolve_sym(&self, addr: u64) -> Option<String> {
-        self.range(..=addr).next_back().map(|(_, s)| s.clone())
-    }
+    fn resolve_sym(&self, addr: u64) -> Option<&str>;
 }
 
 /// A kernel or user space stack trace.
@@ -191,7 +182,7 @@ impl StackTrace {
     /// them from debug info.
     pub fn resolve<R: SymbolResolver>(&mut self, symbols: &R) -> &StackTrace {
         for frame in self.frames.iter_mut() {
-            frame.symbol_name = symbols.resolve_sym(frame.ip)
+            frame.symbol_name = symbols.resolve_sym(frame.ip).map(|s| s.to_string())
         }
 
         self

aya/src/util.rs

@@ -14,8 +14,8 @@ use crate::{
     Pod,
 };
 
-use crate::maps::stack_trace::SimpleSymbolResolver;
 use libc::{if_nametoindex, sysconf, uname, utsname, _SC_PAGESIZE};
+use crate::maps::stack_trace::SymbolResolver;
 
 /// Represents a kernel version, in major.minor.release version.
 // Adapted from https://docs.rs/procfs/latest/procfs/sys/kernel/struct.Version.html.
@@ -202,6 +202,15 @@ fn parse_cpu_ranges(data: &str) -> Result<Vec<u32>, ()> {
     Ok(cpus)
 }
 
+/// The simplest resolver: a direct map from addresses to strings.
+pub type SimpleSymbolResolver = BTreeMap<u64, String>;
+
+impl SymbolResolver for SimpleSymbolResolver {
+    fn resolve_sym(&self, addr: u64) -> Option<&str> {
+        self.range(..=addr).next_back().map(|(_, s)| s.as_str())
+    }
+}
+
 /// Loads kernel symbols from `/proc/kallsyms`.
 ///
 /// The symbols can be passed to [`StackTrace::resolve`](crate::maps::stack_trace::StackTrace::resolve).
@@ -210,8 +219,8 @@ pub fn kernel_symbols() -> Result<SimpleSymbolResolver, io::Error> {
     parse_kernel_symbols(&mut reader)
 }
 
-fn parse_kernel_symbols(reader: impl BufRead) -> Result<BTreeMap<u64, String>, io::Error> {
-    let mut syms = BTreeMap::new();
+fn parse_kernel_symbols(reader: impl BufRead) -> Result<SimpleSymbolResolver, io::Error> {
+    let mut syms = SimpleSymbolResolver::new();
 
     for line in reader.lines() {
         let line = line?;

xtask/public-api/aya.txt

@@ -804,10 +804,9 @@ pub fn aya::maps::stack_trace::StackTraceMap<T>::borrow_mut(&mut self) -> &mut T
 impl<T> core::convert::From<T> for aya::maps::stack_trace::StackTraceMap<T>
 pub fn aya::maps::stack_trace::StackTraceMap<T>::from(t: T) -> T
 pub trait aya::maps::stack_trace::SymbolResolver
-pub fn aya::maps::stack_trace::SymbolResolver::resolve_sym(&self, addr: u64) -> core::option::Option<alloc::string::String>
-impl aya::maps::stack_trace::SymbolResolver for aya::maps::stack_trace::SimpleSymbolResolver
-pub fn aya::maps::stack_trace::SimpleSymbolResolver::resolve_sym(&self, addr: u64) -> core::option::Option<alloc::string::String>
-pub type aya::maps::stack_trace::SimpleSymbolResolver = alloc::collections::btree::map::BTreeMap<u64, alloc::string::String>
+pub fn aya::maps::stack_trace::SymbolResolver::resolve_sym(&self, addr: u64) -> core::option::Option<&str>
+impl aya::maps::stack_trace::SymbolResolver for aya::util::SimpleSymbolResolver
+pub fn aya::util::SimpleSymbolResolver::resolve_sym(&self, addr: u64) -> core::option::Option<&str>
 pub enum aya::maps::Map
 pub aya::maps::Map::Array(aya::maps::MapData)
 pub aya::maps::Map::BloomFilter(aya::maps::MapData)
@@ -6976,10 +6975,11 @@ impl<T> core::borrow::BorrowMut<T> for aya::util::KernelVersion where T: core::m
 pub fn aya::util::KernelVersion::borrow_mut(&mut self) -> &mut T
 impl<T> core::convert::From<T> for aya::util::KernelVersion
 pub fn aya::util::KernelVersion::from(t: T) -> T
-pub fn aya::util::kernel_symbols() -> core::result::Result<aya::maps::stack_trace::SimpleSymbolResolver, std::io::error::Error>
+pub fn aya::util::kernel_symbols() -> core::result::Result<aya::util::SimpleSymbolResolver, std::io::error::Error>
 pub fn aya::util::nr_cpus() -> core::result::Result<usize, std::io::error::Error>
 pub fn aya::util::online_cpus() -> core::result::Result<alloc::vec::Vec<u32>, std::io::error::Error>
 pub fn aya::util::syscall_prefix() -> core::result::Result<&'static str, std::io::error::Error>
+pub type aya::util::SimpleSymbolResolver = alloc::collections::btree::map::BTreeMap<u64, alloc::string::String>
 pub macro aya::include_bytes_aligned!
 pub enum aya::BpfError
 pub aya::BpfError::BtfError(aya_obj::btf::btf::BtfError)