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Don't fail when ptrace::detach returns ESRCH. #68

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Merged
gabrielesvelto merged 1 commit into from
Jan 9, 2023
Merged

Don't fail when ptrace::detach returns ESRCH. #68

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26 changes: 19 additions & 7 deletions src/linux/ptrace_dumper.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,22 @@ impl Drop for PtraceDumper {
}
}

/// PTRACE_DETACH the given pid.
///
/// This handles special errno cases (ESRCH) which we won't consider errors.
fn ptrace_detach(child: Pid) -> Result<(), DumperError> {
let pid = nix::unistd::Pid::from_raw(child);
ptrace::detach(pid, None).or_else(|e| {
// errno is set to ESRCH if the pid no longer exists, but we don't want to error in that
// case.
if e == nix::Error::ESRCH {
Ok(())
} else {
Err(DumperError::PtraceDetachError(child, e))
}
})
}

impl PtraceDumper {
/// Constructs a dumper for extracting information of a given process
/// with a process ID of |pid|.
Expand Down Expand Up @@ -106,7 +122,6 @@ impl PtraceDumper {
/// Suspends a thread by attaching to it.
pub fn suspend_thread(child: Pid) -> Result<(), DumperError> {
use DumperError::PtraceAttachError as AttachErr;
use DumperError::PtraceDetachError as DetachErr;

let pid = nix::unistd::Pid::from_raw(child);
// This may fail if the thread has just died or debugged.
Expand All @@ -116,7 +131,7 @@ impl PtraceDumper {
Ok(_) => break,
Err(_e @ Errno::EINTR) => continue,
Err(e) => {
ptrace::detach(pid, None).map_err(|e| DetachErr(child, e))?;
ptrace_detach(child)?;
return Err(DumperError::WaitPidError(child, e));
}
}
Expand Down Expand Up @@ -145,7 +160,7 @@ impl PtraceDumper {
skip_thread = true;
}
if skip_thread {
ptrace::detach(pid, None).map_err(|e| DetachErr(child, e))?;
ptrace_detach(child)?;
return Err(DumperError::DetachSkippedThread(child));
}
}
Expand All @@ -154,10 +169,7 @@ impl PtraceDumper {

/// Resumes a thread by detaching from it.
pub fn resume_thread(child: Pid) -> Result<(), DumperError> {
use DumperError::PtraceDetachError as DetachErr;
let pid = nix::unistd::Pid::from_raw(child);
ptrace::detach(pid, None).map_err(|e| DetachErr(child, e))?;
Ok(())
ptrace_detach(child)
}

pub fn suspend_threads(&mut self) -> Result<(), DumperError> {
Expand Down