Fixed -exec{}: dup()"d file descriptor was being closed before the process could access it. Fixed -exec (hack ver.): Ditto.

Fortune for collect's current commit: Small blessing − 小吉

src/exec.rs

@@ -18,9 +18,10 @@ use std::{
 fn proc_file<F: ?Sized + AsRawFd>(file: &F) -> PathBuf
 {
     let fd = file.as_raw_fd();
-    //let pid = process::id();
-    //format!("/proc/{pid}/fd/{fd}").into()
-    format!("/dev/fd/{fd}").into()
+    let pid = process::id();
+    //process::Command::new("/bin/ls").arg("-l").arg(format!("/proc/{pid}/fd/")).spawn().unwrap().wait().unwrap();
+    format!("/proc/{pid}/fd/{fd}").into()
+    //format!("/dev/fd/{fd}").into()
 }
 
 /// Attempt to `dup()` a file descriptor into a `RawFile`.
@@ -40,10 +41,10 @@ fn dup_file<F: ?Sized + AsRawFd>(file: &F) -> io::Result<memfile::RawFile>
     Ok(memfile::RawFile::take_ownership_of_unchecked(fd))
 }
 
-fn run_stdin<I>(file: Option<impl Into<fs::File>>, filename: impl AsRef<OsStr>, args: I) -> io::Result<process::Child>
+fn run_stdin<I>(file: Option<impl Into<fs::File>>, filename: impl AsRef<OsStr>, args: I) -> io::Result<(process::Child, Option<fs::File>)>
 where I: IntoIterator<Item = OsString>,
 {
-    let file = {
+    let mut file = {
 	let file: Option<fs::File> = file.map(Into::into);
 	//TODO: Do we need to fcntl() this to make it (the fd) RW?
 	match file {
@@ -65,7 +66,8 @@ where I: IntoIterator<Item = OsString>,
         .stdout(process::Stdio::inherit())
         .stderr(process::Stdio::inherit())
         .spawn()?;
-    if let Some((mut input, mut output)) = file.zip(child.stdin.take()) {
+    //TODO: XXX: Why does `/proc/{pid}/fd/{fd}` **and** `/dev/fd/{fd}` not work for -exec{}, and why foes `Stdio::from(file)` not work for stdin even *afer* re-seeking the file???
+    if let Some((mut input, mut output)) = file.as_mut().zip(child.stdin.take()) {
 	io::copy(&mut input, &mut output)
 	    /*.wrap_err("Failed to pipe file into stdin for child")*/?;
     }
@@ -75,23 +77,23 @@ where I: IntoIterator<Item = OsString>,
     .code()
     .unwrap_or(-1)) //XXX: What should we do if the process terminates without a code (i.e. by a signal?)
      */
-    Ok(child)
+    Ok((child, file))
 }
 
 /// Run a single `-exec` / `-exec{}` and return the (possibly still running) child process if succeeded in spawning.
 ///
 /// The caller must wait for all child processes to exit before the parent does.
 #[inline]
-pub fn run_single<F: ?Sized + AsRawFd>(file: &F, opt: args::ExecMode) -> io::Result<process::Child>
+pub fn run_single<F: ?Sized + AsRawFd>(file: &F, opt: args::ExecMode) -> io::Result<(process::Child, Option<fs::File>)>
 {
-    let input = dup_file(file)?;
+    let input: std::mem::ManuallyDrop<memfile::RawFile> = std::mem::ManuallyDrop::new(dup_file(file)?);
     
     match opt {
 	args::ExecMode::Positional { command, args } => {
-	    run_stdin(None::<fs::File>, command, args.into_iter().map(move |x| x.unwrap_or_else(|| proc_file(&input).into())))
+	    run_stdin(None::<fs::File>, command, args.into_iter().map(|x| x.unwrap_or_else(|| proc_file(&*input).into())))
 	},
 	args::ExecMode::Stdin { command, args } => {
-	    run_stdin(Some(input), command, args)
+	    run_stdin(Some(std::mem::ManuallyDrop::into_inner(input)), command, args)
 	}
     }
 }
@@ -100,7 +102,7 @@ pub fn run_single<F: ?Sized + AsRawFd>(file: &F, opt: args::ExecMode) -> io::Res
 ///
 /// # Returns
 /// An iterator of each (possibly running) spawned child, or the error that occoured when trying to spawn that child from the `exec` option in `opt`.
-pub fn spawn_from<'a, F: ?Sized + AsRawFd>(file: &'a F, opt: Options) -> impl IntoIterator<Item = io::Result<process::Child>> + 'a
+pub fn spawn_from<'a, F: ?Sized + AsRawFd>(file: &'a F, opt: Options) -> impl IntoIterator<Item = io::Result<(process::Child, Option<fs::File>)>> + 'a
 {
     opt.into_opt_exec().map(|x| run_single(file, x))
     //todo!("Loop through `opt.into_exec()`, map the call to `|x| run_single(file, x)`, and return that iterator")
@@ -120,7 +122,7 @@ pub fn spawn_from_sync<'a, F: ?Sized + AsRawFd>(file: &'a F, opt: Options) -> im
 	let idx = move || idx.to_string().header("");
 	match child {
 	    Ok(mut child) => {
-		Ok(child.wait()
+		Ok(child.0.wait()
 		   .wrap_err("Failed to wait on child")
 		   .with_note(|| "The child may have detached itself")
 		   .with_section(idx)?