Squash some errors; only attempt wire communication when necessary

src/filestore.rs

@@ -295,8 +295,7 @@ pub fn parse_format(fp: &mut (impl io::Read + io::Seek)) -> anyhow::Result<(File
                     // was moved between compilation and ingestion. but how...
                     let metadata = match fs::metadata(&filename) {
                         Ok(m) => m,
-                        Err(e) if e.kind() == io::ErrorKind::NotFound => return Ok(None),
+                        Err(_) => return Ok(None),
-                        Err(e) => return Err(e)?,
                     };
                     if !metadata.is_file() {
                         return Ok(None);

src/tracer/client.rs

@@ -421,8 +421,17 @@ impl TracerClient {
         ptrace::setoptions(root_child.into(), ptrace_opts)?;
         // restart child
         ptrace::syscall(nix::unistd::Pid::from(root_child.into()), None)?;
-        loop {
+        let mut continuing = true;
-            let status = waitpid(None, Some(WaitPidFlag::__WALL))?;
+        while continuing {
+            let status = {
+                let status = waitpid(None, Some(WaitPidFlag::__WALL));
+                if status.is_err_and(|e| e == nix::errno::Errno::ECHILD) {
+                    continuing = false;
+                    Ok(WaitStatus::StillAlive)
+                } else {
+                    status
+                }
+            }?;
             // log::trace!("waitpid: {:?}", status);
             let signal = match status {
                 WaitStatus::Stopped(pid, sig) => {
@@ -467,9 +476,6 @@ impl TracerClient {
                     self.log_root(pid, Event::Exit { code });
                     self.store.get_current_mut(pid).unwrap().status =
                         ProcessStatus::Exited(code);
-                    if pid == root_child {
-                        break;
-                    }
                     None
                 }
                 WaitStatus::PtraceEvent(pid, sig, evt) => {
@@ -559,7 +565,7 @@ impl TracerClient {
                 _ => None
             };
 
-            if !self.pending_files.is_empty() || !self.pending_events.is_empty() {
+            if !self.pending_files.is_empty() || !continuing {
                 let mut events = vec![];
                 let mut files = BTreeSet::new();
                 std::mem::swap(&mut events, &mut self.pending_events);