maps,programs: avoid path UTF-8 assumptions

aya/src/bpf.rs

@@ -1,7 +1,6 @@
 use std::{
     borrow::Cow,
     collections::{HashMap, HashSet},
-    ffi::CString,
     fs, io,
     os::{
         fd::{AsFd as _, OwnedFd},
@@ -608,10 +607,6 @@ impl<'a> BpfLoader<'a> {
                         ProgramSection::SchedClassifier => {
                             Program::SchedClassifier(SchedClassifier {
                                 data: ProgramData::new(prog_name, obj, btf_fd, *verifier_log_level),
-                                name: unsafe {
-                                    CString::from_vec_unchecked(Vec::from(name.clone()))
-                                        .into_boxed_c_str()
-                                },
                             })
                         }
                         ProgramSection::CgroupSkb => Program::CgroupSkb(CgroupSkb {
@@ -960,13 +955,6 @@ pub enum BpfError {
         name: u32,
     },
 
-    /// Invalid path
-    #[error("invalid path `{error}`")]
-    InvalidPath {
-        /// The error message
-        error: String,
-    },
-
     /// Error parsing BPF object
     #[error("error parsing BPF object: {0}")]
     ParseError(#[from] ParseError),

aya/src/maps/mod.rs

@@ -515,9 +515,19 @@ impl MapData {
         name: &str,
         btf_fd: Option<BorrowedFd<'_>>,
     ) -> Result<Self, MapError> {
+        use std::os::unix::ffi::OsStrExt as _;
+
         // try to open map in case it's already pinned
-        let map_path = path.as_ref().join(name);
-        let path_string = CString::new(map_path.to_str().unwrap()).unwrap();
+        let path = path.as_ref().join(name);
+        let path_string = match CString::new(path.as_os_str().as_bytes()) {
+            Ok(path) => path,
+            Err(error) => {
+                return Err(MapError::PinError {
+                    name: Some(name.into()),
+                    error: PinError::InvalidPinPath { path, error },
+                });
+            }
+        };
         match bpf_get_object(&path_string).map_err(|(_, io_error)| SyscallError {
             call: "BPF_OBJ_GET",
             io_error,
@@ -540,14 +550,16 @@ impl MapData {
 
     /// Loads a map from a pinned path in bpffs.
     pub fn from_pin<P: AsRef<Path>>(path: P) -> Result<Self, MapError> {
+        use std::os::unix::ffi::OsStrExt as _;
+
+        let path = path.as_ref();
         let path_string =
-            CString::new(path.as_ref().to_string_lossy().into_owned()).map_err(|e| {
-                MapError::PinError {
+            CString::new(path.as_os_str().as_bytes()).map_err(|error| MapError::PinError {
                 name: None,
                 error: PinError::InvalidPinPath {
-                        error: e.to_string(),
+                    path: path.into(),
+                    error,
                 },
-                }
             })?;
 
         let fd = bpf_get_object(&path_string).map_err(|(_, io_error)| SyscallError {
@@ -580,16 +592,15 @@ impl MapData {
     }
 
     pub(crate) fn pin<P: AsRef<Path>>(&mut self, name: &str, path: P) -> Result<(), PinError> {
+        use std::os::unix::ffi::OsStrExt as _;
+
         let Self { fd, pinned, obj: _ } = self;
         if *pinned {
             return Err(PinError::AlreadyPinned { name: name.into() });
         }
-        let map_path = path.as_ref().join(name);
-        let path_string = CString::new(map_path.to_string_lossy().into_owned()).map_err(|e| {
-            PinError::InvalidPinPath {
-                error: e.to_string(),
-            }
-        })?;
+        let path = path.as_ref().join(name);
+        let path_string = CString::new(path.as_os_str().as_bytes())
+            .map_err(|error| PinError::InvalidPinPath { path, error })?;
         bpf_pin_object(*fd, &path_string).map_err(|(_, io_error)| SyscallError {
             call: "BPF_OBJ_PIN",
             io_error,

aya/src/pin.rs

@@ -19,10 +19,14 @@ pub enum PinError {
         name: String,
     },
     /// The path for the BPF object is not valid.
-    #[error("invalid pin path `{error}`")]
+    #[error("invalid pin path `{}`", path.display())]
     InvalidPinPath {
-        /// The error message.
-        error: String,
+        /// The path.
+        path: std::path::PathBuf,
+
+        #[source]
+        /// The source error.
+        error: std::ffi::NulError,
     },
     /// An error ocurred making a syscall.
     #[error(transparent)]

aya/src/programs/kprobe.rs

@@ -1,5 +1,9 @@
 //! Kernel space probes.
-use std::{io, os::fd::AsFd as _, path::Path};
+use std::{
+    io,
+    os::fd::AsFd as _,
+    path::{Path, PathBuf},
+};
 use thiserror::Error;
 
 use crate::{
@@ -68,7 +72,7 @@ impl KProbe {
     ///
     /// The returned value can be used to detach from the given function, see [KProbe::detach].
     pub fn attach(&mut self, fn_name: &str, offset: u64) -> Result<KProbeLinkId, ProgramError> {
-        attach(&mut self.data, self.kind, fn_name, offset, None)
+        attach(&mut self.data, self.kind, Path::new(fn_name), offset, None)
     }
 
     /// Detaches the program.
@@ -114,7 +118,7 @@ pub enum KProbeError {
     #[error("`{filename}`")]
     FileError {
         /// The file name
-        filename: String,
+        filename: PathBuf,
         /// The [`io::Error`] returned from the file operation
         #[source]
         io_error: io::Error,

aya/src/programs/links.rs

@@ -146,10 +146,13 @@ impl FdLink {
     /// # Ok::<(), Error>(())
     /// ```
     pub fn pin<P: AsRef<Path>>(self, path: P) -> Result<PinnedLink, PinError> {
-        let path_string =
-            CString::new(path.as_ref().to_string_lossy().into_owned()).map_err(|e| {
+        use std::os::unix::ffi::OsStrExt as _;
+
+        let path = path.as_ref();
+        let path_string = CString::new(path.as_os_str().as_bytes()).map_err(|error| {
             PinError::InvalidPinPath {
-                    error: e.to_string(),
+                path: path.into(),
+                error,
             }
         })?;
         bpf_pin_object(self.fd.as_raw_fd(), &path_string).map_err(|(_, io_error)| {
@@ -158,7 +161,7 @@ impl FdLink {
                 io_error,
             }
         })?;
-        Ok(PinnedLink::new(PathBuf::from(path.as_ref()), self))
+        Ok(PinnedLink::new(path.into(), self))
     }
 }
 
@@ -203,7 +206,10 @@ impl PinnedLink {
 
     /// Creates a [`crate::programs::links::PinnedLink`] from a valid path on bpffs.
     pub fn from_pin<P: AsRef<Path>>(path: P) -> Result<Self, LinkError> {
-        let path_string = CString::new(path.as_ref().to_string_lossy().to_string()).unwrap();
+        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)| {
             LinkError::SyscallError(SyscallError {
                 call: "BPF_OBJ_GET",

aya/src/programs/mod.rs

@@ -487,9 +487,10 @@ impl<T: Link> ProgramData<T> {
         path: P,
         verifier_log_level: VerifierLogLevel,
     ) -> Result<Self, ProgramError> {
-        let path_string =
-            CString::new(path.as_ref().as_os_str().to_string_lossy().as_bytes()).unwrap();
+        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,
@@ -520,6 +521,8 @@ fn unload_program<T: Link>(data: &mut ProgramData<T>) -> Result<(), ProgramError
 }
 
 fn pin_program<T: Link, P: AsRef<Path>>(data: &ProgramData<T>, path: P) -> Result<(), PinError> {
+    use std::os::unix::ffi::OsStrExt as _;
+
     let fd = data.fd.as_ref().ok_or(PinError::NoFd {
         name: data
             .name
@@ -527,10 +530,11 @@ fn pin_program<T: Link, P: AsRef<Path>>(data: &ProgramData<T>, path: P) -> Resul
             .unwrap_or("<unknown program>")
             .to_string(),
     })?;
-    let path_string = CString::new(path.as_ref().to_string_lossy().into_owned()).map_err(|e| {
-        PinError::InvalidPinPath {
-            error: e.to_string(),
-        }
+    let path = path.as_ref();
+    let path_string =
+        CString::new(path.as_os_str().as_bytes()).map_err(|error| PinError::InvalidPinPath {
+            path: path.into(),
+            error,
         })?;
     bpf_pin_object(fd.as_fd().as_raw_fd(), &path_string).map_err(|(_, io_error)| SyscallError {
         call: "BPF_OBJ_PIN",
@@ -1073,7 +1077,10 @@ impl ProgramInfo {
 
     /// Loads a program from a pinned path in bpffs.
     pub fn from_pin<P: AsRef<Path>>(path: P) -> Result<Self, ProgramError> {
-        let path_string = CString::new(path.as_ref().to_str().unwrap()).unwrap();
+        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,

aya/src/programs/probe.rs

@@ -1,10 +1,12 @@
 use crate::util::KernelVersion;
 use libc::pid_t;
 use std::{
+    ffi::{OsStr, OsString},
+    fmt::Write as _,
     fs::{self, OpenOptions},
     io::{self, Write},
     os::fd::{AsFd as _, AsRawFd as _, OwnedFd},
-    path::Path,
+    path::{Path, PathBuf},
     process,
     sync::atomic::{AtomicUsize, Ordering},
 };
@@ -42,16 +44,64 @@ impl ProbeKind {
     }
 }
 
+pub(crate) fn lines(bytes: &[u8]) -> impl Iterator<Item = &OsStr> {
+    use std::os::unix::ffi::OsStrExt as _;
+
+    bytes.as_ref().split(|b| b == &b'\n').map(|mut line| {
+        while let [stripped @ .., c] = line {
+            if c.is_ascii_whitespace() {
+                line = stripped;
+                continue;
+            }
+            break;
+        }
+        OsStr::from_bytes(line)
+    })
+}
+
+pub(crate) trait OsStringExt {
+    fn starts_with(&self, needle: &OsStr) -> bool;
+    fn ends_with(&self, needle: &OsStr) -> bool;
+    fn strip_prefix(&self, prefix: &OsStr) -> Option<&OsStr>;
+    fn strip_suffix(&self, suffix: &OsStr) -> Option<&OsStr>;
+}
+
+impl OsStringExt for OsStr {
+    fn starts_with(&self, needle: &OsStr) -> bool {
+        use std::os::unix::ffi::OsStrExt as _;
+        self.as_bytes().starts_with(needle.as_bytes())
+    }
+
+    fn ends_with(&self, needle: &OsStr) -> bool {
+        use std::os::unix::ffi::OsStrExt as _;
+        self.as_bytes().ends_with(needle.as_bytes())
+    }
+
+    fn strip_prefix(&self, prefix: &OsStr) -> Option<&OsStr> {
+        use std::os::unix::ffi::OsStrExt as _;
+        self.as_bytes()
+            .strip_prefix(prefix.as_bytes())
+            .map(Self::from_bytes)
+    }
+
+    fn strip_suffix(&self, suffix: &OsStr) -> Option<&OsStr> {
+        use std::os::unix::ffi::OsStrExt as _;
+        self.as_bytes()
+            .strip_suffix(suffix.as_bytes())
+            .map(Self::from_bytes)
+    }
+}
+
 #[derive(Debug)]
 pub(crate) struct ProbeEvent {
     kind: ProbeKind,
-    event_alias: String,
+    event_alias: OsString,
 }
 
 pub(crate) fn attach<T: Link + From<PerfLinkInner>>(
     program_data: &mut ProgramData<T>,
     kind: ProbeKind,
-    fn_name: &str,
+    fn_name: &Path,
     offset: u64,
     pid: Option<pid_t>,
 ) -> Result<T::Id, ProgramError> {
@@ -90,7 +140,7 @@ pub(crate) fn detach_debug_fs(event: ProbeEvent) -> Result<(), ProgramError> {
 
 fn create_as_probe(
     kind: ProbeKind,
-    fn_name: &str,
+    fn_name: &Path,
     offset: u64,
     pid: Option<pid_t>,
 ) -> Result<OwnedFd, ProgramError> {
@@ -126,10 +176,10 @@ fn create_as_probe(
 
 fn create_as_trace_point(
     kind: ProbeKind,
-    name: &str,
+    name: &Path,
     offset: u64,
     pid: Option<pid_t>,
-) -> Result<(OwnedFd, String), ProgramError> {
+) -> Result<(OwnedFd, OsString), ProgramError> {
     use ProbeKind::*;
 
     let tracefs = find_tracefs_path()?;
@@ -142,7 +192,7 @@ fn create_as_trace_point(
     };
 
     let category = format!("{}s", kind.pmu());
-    let tpid = read_sys_fs_trace_point_id(tracefs, &category, &event_alias)?;
+    let tpid = read_sys_fs_trace_point_id(tracefs, &category, event_alias.as_ref())?;
     let fd = perf_event_open_trace_point(tpid, pid).map_err(|(_code, io_error)| SyscallError {
         call: "perf_event_open",
         io_error,
@@ -154,9 +204,10 @@ fn create_as_trace_point(
 fn create_probe_event(
     tracefs: &Path,
     kind: ProbeKind,
-    fn_name: &str,
+    fn_name: &Path,
     offset: u64,
-) -> Result<String, (String, io::Error)> {
+) -> Result<OsString, (PathBuf, io::Error)> {
+    use std::os::unix::ffi::OsStrExt as _;
     use ProbeKind::*;
 
     let events_file_name = tracefs.join(format!("{}_events", kind.pmu()));
@@ -165,93 +216,129 @@ fn create_probe_event(
         KRetProbe | URetProbe => 'r',
     };
 
-    let fixed_fn_name = fn_name.replace(['.', '/', '-'], "_");
+    let fn_name = fn_name.as_os_str();
 
-    let event_alias = format!(
-        "aya_{}_{}_{}_{:#x}_{}",
+    let mut event_alias = OsString::new();
+    write!(
+        &mut event_alias,
+        "aya_{}_{}_",
         process::id(),
         probe_type_prefix,
-        fixed_fn_name,
+    )
+    .unwrap();
+    for b in fn_name.as_bytes() {
+        let b = match *b {
+            b'.' | b'/' | b'-' => b'_',
+            b => b,
+        };
+        event_alias.push(OsStr::from_bytes(&[b]));
+    }
+    write!(
+        &mut event_alias,
+        "_{:#x}_{}",
         offset,
         PROBE_NAME_INDEX.fetch_add(1, Ordering::AcqRel)
-    );
-    let offset_suffix = match kind {
-        KProbe => format!("+{offset}"),
-        UProbe | URetProbe => format!(":{offset:#x}"),
-        _ => String::new(),
+    )
+    .unwrap();
+
+    let mut probe = OsString::new();
+    write!(&mut probe, "{}:{}s/", probe_type_prefix, kind.pmu(),).unwrap();
+    probe.push(&event_alias);
+    probe.push(" ");
+    probe.push(fn_name);
+    match kind {
+        KProbe => write!(&mut probe, "+{offset}").unwrap(),
+        UProbe | URetProbe => write!(&mut probe, ":{offset:#x}").unwrap(),
+        _ => {}
     };
-    let probe = format!(
-        "{}:{}s/{} {}{}\n",
-        probe_type_prefix,
-        kind.pmu(),
-        event_alias,
-        fn_name,
-        offset_suffix
-    );
+    probe.push("\n");
 
-    let mut events_file = OpenOptions::new()
+    OpenOptions::new()
         .append(true)
         .open(&events_file_name)
-        .map_err(|e| (events_file_name.display().to_string(), e))?;
-
-    events_file
-        .write_all(probe.as_bytes())
-        .map_err(|e| (events_file_name.display().to_string(), e))?;
+        .and_then(|mut events_file| events_file.write_all(probe.as_bytes()))
+        .map_err(|e| (events_file_name, e))?;
 
     Ok(event_alias)
 }
 
-fn delete_probe_event(tracefs: &Path, event: ProbeEvent) -> Result<(), (String, io::Error)> {
+fn delete_probe_event(tracefs: &Path, event: ProbeEvent) -> Result<(), (PathBuf, io::Error)> {
+    use std::os::unix::ffi::OsStrExt as _;
+
     let ProbeEvent { kind, event_alias } = event;
     let events_file_name = tracefs.join(format!("{}_events", kind.pmu()));
 
-    let events = fs::read_to_string(&events_file_name)
-        .map_err(|e| (events_file_name.display().to_string(), e))?;
-
-    let found = events.lines().any(|line| line.contains(&event_alias));
+    fs::read(&events_file_name)
+        .and_then(|events| {
+            let found = lines(&events).any(|line| {
+                let mut line = line.as_bytes();
+                // See [`create_probe_event`] and the documentation:
+                //
+                // https://docs.kernel.org/trace/kprobetrace.html
+                //
+                // https://docs.kernel.org/trace/uprobetracer.html
+                loop {
+                    match line.split_first() {
+                        None => break false,
+                        Some((b, rest)) => {
+                            line = rest;
+                            if *b == b'/' {
+                                break line.starts_with(event_alias.as_bytes());
+                            }
+                        }
+                    }
+                }
+            });
 
             if found {
-        let mut events_file = OpenOptions::new()
+                OpenOptions::new()
                     .append(true)
                     .open(&events_file_name)
-            .map_err(|e| (events_file_name.display().to_string(), e))?;
-
-        let rm = format!("-:{event_alias}\n");
-
-        events_file
-            .write_all(rm.as_bytes())
-            .map_err(|e| (events_file_name.display().to_string(), e))?;
-    }
+                    .and_then(|mut events_file| {
+                        let mut rm = OsString::new();
+                        rm.push("-:");
+                        rm.push(event_alias);
+                        rm.push("\n");
 
+                        events_file.write_all(rm.as_bytes())
+                    })
+            } else {
                 Ok(())
+            }
+        })
+        .map_err(|e| (events_file_name, e))
 }
 
-fn read_sys_fs_perf_type(pmu: &str) -> Result<u32, (String, io::Error)> {
-    let file = format!("/sys/bus/event_source/devices/{pmu}/type");
+fn read_sys_fs_perf_type(pmu: &str) -> Result<u32, (PathBuf, io::Error)> {
+    let file = Path::new("/sys/bus/event_source/devices")
+        .join(pmu)
+        .join("type");
 
-    let perf_ty = fs::read_to_string(&file).map_err(|e| (file.clone(), e))?;
-    let perf_ty = perf_ty
+    fs::read_to_string(&file)
+        .and_then(|perf_ty| {
+            perf_ty
                 .trim()
                 .parse::<u32>()
-        .map_err(|e| (file, io::Error::new(io::ErrorKind::Other, e)))?;
-
-    Ok(perf_ty)
+                .map_err(|e| io::Error::new(io::ErrorKind::Other, e))
+        })
+        .map_err(|e| (file, e))
 }
 
-fn read_sys_fs_perf_ret_probe(pmu: &str) -> Result<u32, (String, io::Error)> {
-    let file = format!("/sys/bus/event_source/devices/{pmu}/format/retprobe");
-
-    let data = fs::read_to_string(&file).map_err(|e| (file.clone(), e))?;
+fn read_sys_fs_perf_ret_probe(pmu: &str) -> Result<u32, (PathBuf, io::Error)> {
+    let file = Path::new("/sys/bus/event_source/devices")
+        .join(pmu)
+        .join("format/retprobe");
 
+    fs::read_to_string(&file)
+        .and_then(|data| {
             let mut parts = data.trim().splitn(2, ':').skip(1);
-    let config = parts.next().ok_or_else(|| {
-        (
-            file.clone(),
-            io::Error::new(io::ErrorKind::Other, "invalid format"),
-        )
-    })?;
+            let config = parts
+                .next()
+                .ok_or_else(|| io::Error::new(io::ErrorKind::Other, "invalid format"))?;
 
             config
                 .parse::<u32>()
-        .map_err(|e| (file, io::Error::new(io::ErrorKind::Other, e)))
+                .map_err(|e| io::Error::new(io::ErrorKind::Other, e))
+        })
+        .map_err(|e| (file, e))
 }

aya/src/programs/tc.rs

@@ -74,7 +74,6 @@ pub enum TcAttachType {
 #[doc(alias = "BPF_PROG_TYPE_SCHED_CLS")]
 pub struct SchedClassifier {
     pub(crate) data: ProgramData<SchedClassifierLink>,
-    pub(crate) name: Box<CStr>,
 }
 
 /// Errors from TC programs
@@ -158,12 +157,15 @@ impl SchedClassifier {
         let prog_fd = prog_fd.as_raw_fd();
         let if_index = ifindex_from_ifname(interface)
             .map_err(|io_error| TcError::NetlinkError { io_error })?;
+        let name = self.data.name.as_deref().unwrap_or_default();
+        // TODO: avoid this unwrap by adding a new error variant.
+        let name = CString::new(name).unwrap();
         let (priority, handle) = unsafe {
             netlink_qdisc_attach(
                 if_index as i32,
                 &attach_type,
                 prog_fd,
-                &self.name,
+                &name,
                 options.priority,
                 options.handle,
             )
@@ -204,10 +206,7 @@ impl SchedClassifier {
     /// the program being unloaded from the kernel if it is still pinned.
     pub fn from_pin<P: AsRef<Path>>(path: P) -> Result<Self, ProgramError> {
         let data = ProgramData::from_pinned_path(path, VerifierLogLevel::default())?;
-        let cname = CString::new(data.name.clone().unwrap_or_default())
-            .unwrap()
-            .into_boxed_c_str();
-        Ok(Self { data, name: cname })
+        Ok(Self { data })
     }
 }
 

aya/src/programs/trace_point.rs

@@ -86,7 +86,7 @@ impl TracePoint {
         let prog_fd = prog_fd.as_fd();
         let prog_fd = prog_fd.as_raw_fd();
         let tracefs = find_tracefs_path()?;
-        let id = read_sys_fs_trace_point_id(tracefs, category, name)?;
+        let id = read_sys_fs_trace_point_id(tracefs, category, name.as_ref())?;
         let fd =
             perf_event_open_trace_point(id, None).map_err(|(_code, io_error)| SyscallError {
                 call: "perf_event_open_trace_point",
@@ -149,7 +149,7 @@ impl TryFrom<FdLink> for TracePointLink {
 pub(crate) fn read_sys_fs_trace_point_id(
     tracefs: &Path,
     category: &str,
-    name: &str,
+    name: &Path,
 ) -> Result<u32, TracePointError> {
     let file = tracefs.join("events").join(category).join(name).join("id");
 

aya/src/programs/uprobe.rs

@@ -4,7 +4,7 @@ use object::{Object, ObjectSection, ObjectSymbol};
 use std::{
     borrow::Cow,
     error::Error,
-    ffi::CStr,
+    ffi::{CStr, OsStr, OsString},
     fs,
     io::{self, BufRead, Cursor, Read},
     mem,
@@ -19,7 +19,7 @@ use crate::{
     programs::{
         define_link_wrapper, load_program,
         perf_attach::{PerfLinkIdInner, PerfLinkInner},
-        probe::{attach, ProbeKind},
+        probe::{attach, OsStringExt as _, ProbeKind},
         FdLink, LinkError, ProgramData, ProgramError,
     },
     sys::bpf_link_get_info_by_fd,
@@ -83,7 +83,7 @@ impl UProbe {
         target: T,
         pid: Option<pid_t>,
     ) -> Result<UProbeLinkId, ProgramError> {
-        let path = resolve_attach_path(&target, pid)?;
+        let path = resolve_attach_path(target.as_ref(), pid)?;
 
         let sym_offset = if let Some(fn_name) = fn_name {
             resolve_symbol(&path, fn_name).map_err(|error| UProbeError::SymbolError {
@@ -124,37 +124,33 @@ impl UProbe {
     }
 }
 
-fn resolve_attach_path<T: AsRef<Path>>(
-    target: &T,
-    pid: Option<pid_t>,
-) -> Result<Cow<'_, str>, UProbeError> {
+fn resolve_attach_path(target: &Path, pid: Option<pid_t>) -> Result<Cow<'_, Path>, UProbeError> {
     // Look up the path for the target. If it there is a pid, and the target is a library name
     // that is in the process's memory map, use the path of that library. Otherwise, use the target as-is.
-    let target = target.as_ref();
-    let invalid_target = || UProbeError::InvalidTarget {
-        path: target.to_owned(),
-    };
-    let target_str = target.to_str().ok_or_else(invalid_target)?;
     pid.and_then(|pid| {
-        find_lib_in_proc_maps(pid, target_str)
+        find_lib_in_proc_maps(pid, target)
             .map_err(|io_error| UProbeError::FileError {
-                filename: format!("/proc/{pid}/maps"),
+                filename: Path::new("/proc").join(pid.to_string()).join("maps"),
                 io_error,
             })
             .map(|v| v.map(Cow::Owned))
             .transpose()
     })
-    .or_else(|| target.is_absolute().then(|| Ok(Cow::Borrowed(target_str))))
+    .or_else(|| target.is_absolute().then(|| Ok(Cow::Borrowed(target))))
     .or_else(|| {
         LD_SO_CACHE
             .as_ref()
             .map_err(|error| UProbeError::InvalidLdSoCache {
                 io_error: error.clone(),
             })
-            .map(|cache| cache.resolve(target_str).map(Cow::Borrowed))
+            .map(|cache| cache.resolve(target).map(Cow::Borrowed))
             .transpose()
     })
-    .unwrap_or_else(|| Err(invalid_target()))
+    .unwrap_or_else(|| {
+        Err(UProbeError::InvalidTarget {
+            path: target.to_owned(),
+        })
+    })
 }
 
 // Only run this test on linux with glibc because only in that configuration do we know that we'll
@@ -171,7 +167,8 @@ fn test_resolve_attach_path() {
 
     // Now let's resolve the path to libc. It should exist in the current process's memory map and
     // then in the ld.so.cache.
-    let libc_path = resolve_attach_path(&"libc", Some(pid)).unwrap();
+    let libc_path = resolve_attach_path("libc".as_ref(), Some(pid)).unwrap();
+    let libc_path = libc_path.to_str().unwrap();
 
     // Make sure we got a path that contains libc.
     assert!(libc_path.contains("libc"), "libc_path: {}", libc_path);
@@ -242,52 +239,60 @@ pub enum UProbeError {
     #[error("`{filename}`")]
     FileError {
         /// The file name
-        filename: String,
+        filename: PathBuf,
         /// The [`io::Error`] returned from the file operation
         #[source]
         io_error: io::Error,
     },
 }
 
-fn proc_maps_libs(pid: pid_t) -> Result<Vec<(String, String)>, io::Error> {
+fn proc_maps_libs(pid: pid_t) -> Result<Vec<(OsString, PathBuf)>, io::Error> {
+    use std::os::unix::ffi::OsStrExt as _;
+
     let maps_file = format!("/proc/{pid}/maps");
-    let data = fs::read_to_string(maps_file)?;
-
-    Ok(data
-        .lines()
-        .filter_map(|line| {
-            let line = line.split_whitespace().last()?;
-            if line.starts_with('/') {
-                let path = PathBuf::from(line);
-                let key = path.file_name().unwrap().to_string_lossy().into_owned();
-                Some((key, path.to_string_lossy().to_string()))
-            } else {
-                None
+    let data = fs::read(maps_file)?;
+
+    let libs = data
+        .split(|b| b == &b'\n')
+        .filter_map(|mut line| {
+            while let [stripped @ .., c] = line {
+                if c.is_ascii_whitespace() {
+                    line = stripped;
+                    continue;
                 }
+                break;
+            }
+            let path = line.split(|b| b.is_ascii_whitespace()).last()?;
+            let path = Path::new(OsStr::from_bytes(path));
+            path.is_absolute()
+                .then(|| {
+                    path.file_name()
+                        .map(|file_name| (file_name.to_owned(), path.to_owned()))
+                })
+                .flatten()
         })
-        .collect())
+        .collect();
+    Ok(libs)
 }
 
-fn find_lib_in_proc_maps(pid: pid_t, lib: &str) -> Result<Option<String>, io::Error> {
+fn find_lib_in_proc_maps(pid: pid_t, lib: &Path) -> Result<Option<PathBuf>, io::Error> {
     let libs = proc_maps_libs(pid)?;
 
-    let ret = if lib.contains(".so") {
-        libs.into_iter().find(|(k, _)| k.as_str().starts_with(lib))
-    } else {
-        libs.into_iter().find(|(k, _)| {
-            k.strip_prefix(lib)
-                .map(|k| k.starts_with(".so") || k.starts_with('-'))
-                .unwrap_or_default()
-        })
-    };
+    let lib = lib.as_os_str();
+    let lib = lib.strip_suffix(OsStr::new(".so")).unwrap_or(lib);
 
-    Ok(ret.map(|(_, v)| v))
+    Ok(libs.into_iter().find_map(|(file_name, path)| {
+        file_name.strip_prefix(lib).and_then(|suffix| {
+            (suffix.starts_with(OsStr::new(".so")) || suffix.starts_with(OsStr::new("-")))
+                .then_some(path)
+        })
+    }))
 }
 
 #[derive(Debug)]
 pub(crate) struct CacheEntry {
-    key: String,
-    value: String,
+    key: OsString,
+    value: OsString,
     _flags: i32,
 }
 
@@ -368,11 +373,16 @@ impl LdSoCache {
                 }
 
                 let read_str = |pos| {
+                    use std::os::unix::ffi::OsStrExt as _;
+                    OsStr::from_bytes(
                         unsafe {
-                        CStr::from_ptr(cursor.get_ref()[offset + pos..].as_ptr() as *const c_char)
+                            CStr::from_ptr(
+                                cursor.get_ref()[offset + pos..].as_ptr() as *const c_char
+                            )
                         }
-                    .to_string_lossy()
-                    .into_owned()
+                        .to_bytes(),
+                    )
+                    .to_owned()
                 };
 
                 let key = read_str(k_pos);
@@ -389,16 +399,18 @@ impl LdSoCache {
         Ok(Self { entries })
     }
 
-    fn resolve(&self, lib: &str) -> Option<&str> {
-        let lib = if !lib.contains(".so") {
-            lib.to_string() + ".so"
-        } else {
-            lib.to_string()
-        };
+    fn resolve(&self, lib: &Path) -> Option<&Path> {
+        let lib = lib.as_os_str();
+        let lib = lib.strip_suffix(OsStr::new(".so")).unwrap_or(lib);
         self.entries
             .iter()
-            .find(|entry| entry.key.starts_with(&lib))
-            .map(|entry| entry.value.as_str())
+            .find_map(|CacheEntry { key, value, _flags }| {
+                key.strip_prefix(lib).and_then(|suffix| {
+                    suffix
+                        .starts_with(OsStr::new(".so"))
+                        .then_some(Path::new(value.as_os_str()))
+                })
+            })
     }
 }
 
@@ -420,7 +432,7 @@ enum ResolveSymbolError {
     SectionFileRangeNone(String, Result<String, object::Error>),
 }
 
-fn resolve_symbol(path: &str, symbol: &str) -> Result<u64, ResolveSymbolError> {
+fn resolve_symbol(path: &Path, symbol: &str) -> Result<u64, ResolveSymbolError> {
     let data = fs::read(path)?;
     let obj = object::read::File::parse(&*data)?;
 

aya/src/programs/xdp.rs

@@ -100,6 +100,7 @@ impl Xdp {
     /// [`XdpError::NetlinkError`] is returned for older
     /// kernels.
     pub fn attach(&mut self, interface: &str, flags: XdpFlags) -> Result<XdpLinkId, ProgramError> {
+        // TODO: avoid this unwrap by adding a new error variant.
         let c_interface = CString::new(interface).unwrap();
         let if_index = unsafe { if_nametoindex(c_interface.as_ptr()) };
         if if_index == 0 {

aya/src/sys/perf_event.rs

@@ -2,6 +2,7 @@ use std::{
     ffi::{c_long, CString},
     io, mem,
     os::fd::{BorrowedFd, FromRawFd as _, OwnedFd},
+    path::Path,
 };
 
 use libc::{c_int, pid_t};
@@ -62,17 +63,19 @@ pub(crate) fn perf_event_open_bpf(cpu: c_int) -> SysResult<OwnedFd> {
 pub(crate) fn perf_event_open_probe(
     ty: u32,
     ret_bit: Option<u32>,
-    name: &str,
+    name: &Path,
     offset: u64,
     pid: Option<pid_t>,
 ) -> SysResult<OwnedFd> {
+    use std::os::unix::ffi::OsStrExt as _;
+
     let mut attr = unsafe { mem::zeroed::<perf_event_attr>() };
 
     if let Some(ret_bit) = ret_bit {
         attr.config = 1 << ret_bit;
     }
 
-    let c_name = CString::new(name).unwrap();
+    let c_name = CString::new(name.as_os_str().as_bytes()).unwrap();
 
     attr.size = mem::size_of::<perf_event_attr>() as u32;
     attr.type_ = ty;

xtask/public-api/aya.txt

@@ -1752,7 +1752,8 @@ pub enum aya::pin::PinError
 pub aya::pin::PinError::AlreadyPinned
 pub aya::pin::PinError::AlreadyPinned::name: alloc::string::String
 pub aya::pin::PinError::InvalidPinPath
-pub aya::pin::PinError::InvalidPinPath::error: alloc::string::String
+pub aya::pin::PinError::InvalidPinPath::error: alloc::ffi::c_str::NulError
+pub aya::pin::PinError::InvalidPinPath::path: std::path::PathBuf
 pub aya::pin::PinError::NoFd
 pub aya::pin::PinError::NoFd::name: alloc::string::String
 pub aya::pin::PinError::SyscallError(crate::sys::SyscallError)
@@ -2860,7 +2861,7 @@ pub fn aya::programs::fexit::FExitLinkId::from(t: T) -> T
 pub mod aya::programs::kprobe
 pub enum aya::programs::kprobe::KProbeError
 pub aya::programs::kprobe::KProbeError::FileError
-pub aya::programs::kprobe::KProbeError::FileError::filename: alloc::string::String
+pub aya::programs::kprobe::KProbeError::FileError::filename: std::path::PathBuf
 pub aya::programs::kprobe::KProbeError::FileError::io_error: std::io::error::Error
 impl core::convert::From<aya::programs::kprobe::KProbeError> for aya::programs::ProgramError
 pub fn aya::programs::ProgramError::from(source: aya::programs::kprobe::KProbeError) -> Self
@@ -4330,7 +4331,7 @@ pub fn aya::programs::trace_point::TracePointLinkId::from(t: T) -> T
 pub mod aya::programs::uprobe
 pub enum aya::programs::uprobe::UProbeError
 pub aya::programs::uprobe::UProbeError::FileError
-pub aya::programs::uprobe::UProbeError::FileError::filename: alloc::string::String
+pub aya::programs::uprobe::UProbeError::FileError::filename: std::path::PathBuf
 pub aya::programs::uprobe::UProbeError::FileError::io_error: std::io::error::Error
 pub aya::programs::uprobe::UProbeError::InvalidLdSoCache
 pub aya::programs::uprobe::UProbeError::InvalidLdSoCache::io_error: alloc::sync::Arc<std::io::error::Error>
@@ -4814,7 +4815,7 @@ impl<T> core::convert::From<T> for aya::programs::extension::ExtensionError
 pub fn aya::programs::extension::ExtensionError::from(t: T) -> T
 pub enum aya::programs::KProbeError
 pub aya::programs::KProbeError::FileError
-pub aya::programs::KProbeError::FileError::filename: alloc::string::String
+pub aya::programs::KProbeError::FileError::filename: std::path::PathBuf
 pub aya::programs::KProbeError::FileError::io_error: std::io::error::Error
 impl core::convert::From<aya::programs::kprobe::KProbeError> for aya::programs::ProgramError
 pub fn aya::programs::ProgramError::from(source: aya::programs::kprobe::KProbeError) -> Self
@@ -5442,7 +5443,7 @@ impl<T> core::convert::From<T> for aya::programs::trace_point::TracePointError
 pub fn aya::programs::trace_point::TracePointError::from(t: T) -> T
 pub enum aya::programs::UProbeError
 pub aya::programs::UProbeError::FileError
-pub aya::programs::UProbeError::FileError::filename: alloc::string::String
+pub aya::programs::UProbeError::FileError::filename: std::path::PathBuf
 pub aya::programs::UProbeError::FileError::io_error: std::io::error::Error
 pub aya::programs::UProbeError::InvalidLdSoCache
 pub aya::programs::UProbeError::InvalidLdSoCache::io_error: alloc::sync::Arc<std::io::error::Error>
@@ -6988,8 +6989,6 @@ pub aya::BpfError::BtfRelocationError(aya_obj::btf::relocation::BtfRelocationErr
 pub aya::BpfError::FileError
 pub aya::BpfError::FileError::error: std::io::error::Error
 pub aya::BpfError::FileError::path: std::path::PathBuf
-pub aya::BpfError::InvalidPath
-pub aya::BpfError::InvalidPath::error: alloc::string::String
 pub aya::BpfError::MapError(aya::maps::MapError)
 pub aya::BpfError::NoBTF
 pub aya::BpfError::NoPinPath