Implemented `-exec/{}` implementation functionality.

Added file sealing for making `-exec/{}` better (esp. for memfile mode.)

Fixed `errors` being shit.

Removed `memfile-preallocate` from `mode-memfile` feature: It is unneeded.

Fortune for collect's current commit: Middle blessing − 中吉

Cargo.toml

@@ -24,7 +24,7 @@ default = ["mode-memfile", "logging"]
 
 # Mode: default
 # Use physical-memory backed kernel file-descriptors. (see feature `memfile`.)
-mode-memfile = ["memfile-preallocate"] #, "tracing/release_max_level_warn"]
+mode-memfile = ["memfile"] #, "tracing/release_max_level_warn"]
 
 # Mode: alternative
 # Use non-physical memory allocated buffers.

src/errors.rs

@@ -1,24 +1,28 @@
 //! Errors and helpers for errors.
+//TODO: Comment how this works (controllably optional simple or complex `main()` error messages.)
 use super::*;
 use std::{
     fmt,
     error,
 };
+use std::os::unix::prelude::*;
 
 pub const DEFAULT_USE_ENV: bool = std::option_env!("NO_RT_ERROR_CTL").is_none();
 
 pub type DispersedResult<T, const USE_ENV: bool = DEFAULT_USE_ENV> = Result<T, Dispersed<USE_ENV>>;
 
 pub const ENV_NAME: &'static str = "RUST_VERBOSE";
-const DEFAULT_ENV_VERBOSE: DispersedVerbosity = match std::option_env!("DEFAULT_ERROR") {
-    Some("1") |
-    Some("V") |
-    Some("verbose") |
-    Some("VERBOSE") |
-    Some("v") => DispersedVerbosity::Verbose,
-    Some("0") |
-    _ => DispersedVerbosity::static_default(),
-};
+lazy_static!{
+    static ref DEFAULT_ENV_VERBOSE: DispersedVerbosity = match std::option_env!("DEFAULT_ERROR") {
+	Some("1") |
+	Some("V") |
+	Some("verbose") |
+	Some("VERBOSE") |
+	Some("v") => DispersedVerbosity::Verbose,
+	Some("0") |
+	_ => DispersedVerbosity::static_default(),
+    };
+}
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Copy)]
 #[repr(u8)]
@@ -43,7 +47,7 @@ impl Default for DispersedVerbosity
     #[inline]
     fn default() -> Self
     {
-	DEFAULT_ENV_VERBOSE
+	*DEFAULT_ENV_VERBOSE
     }
 }
 
@@ -68,13 +72,13 @@ fn get_env_value() -> DispersedVerbosity
     match std::env::var_os(ENV_NAME) {
 	Some(mut value) => {
 	    value.make_ascii_lowercase();
-	    match value {
-		"1" |
-		"v" |
-		"verbose" => DispersedVerbosity::Verbose,
-		"0" |
-		"s" |
-		"simple" => DispersedVerbosity::Simple,
+	    match value.as_bytes() {
+		b"1" |
+		b"v" |
+		b"verbose" => DispersedVerbosity::Verbose,
+		b"0" |
+		b"s" |
+		b"simple" => DispersedVerbosity::Simple,
 		_ => DispersedVerbosity::default(),
 	    }
 	},
@@ -115,7 +119,7 @@ impl<const E: bool> Dispersed<E>
 impl Dispersed<false>
 {
     #[inline(always)] 
-    pub const fn obey_env(self) -> Dispersed<true>
+    pub fn obey_env(self) -> Dispersed<true>
     {
 	Dispersed(self.0)
     }
@@ -124,16 +128,16 @@ impl Dispersed<false>
 impl Dispersed<true>
 {
     #[inline(always)]
-    pub const fn ignore_env(self) -> Dispersed<false>
+    pub fn ignore_env(self) -> Dispersed<false>
     {
-	Dispersed(self.1)
+	Dispersed(self.0)
     }
 }
 
 impl<const E: bool> Dispersed<E>
 {
     #[inline(always)] 
-    pub const fn set_env<const To: bool>(self) -> Dispersed<To>
+    pub fn set_env<const To: bool>(self) -> Dispersed<To>
     {
 	Dispersed(self.0)
     }
@@ -143,14 +147,14 @@ impl error::Error for Dispersed<true>
 {
     #[inline] 
     fn source(&self) -> Option<&(dyn error::Error + 'static)> {
-	self.0
+	self.0.source()
     }
 }
 impl error::Error for Dispersed<false>
 {
     #[inline] 
     fn source(&self) -> Option<&(dyn error::Error + 'static)> {
-	self.0
+	self.0.source()
     }
 }
 

src/exec.rs

@@ -39,17 +39,17 @@ 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: 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>
 where I: IntoIterator<Item = OsString>,
 {
     let file = {
-	let mut file: fs::File = file.into();
+	let mut file: Option<fs::File> = file.map(Into::into);
 	//TODO: Do we need to fcntl() this to make it (the fd) RW?
 	file
     };
     let child = process::Command::new(filename)
         .args(args)
-        .stdin(process::Stdio::from(file))
+        .stdin(file.map(|file| process::Stdio::from(file)).unwrap_or_else(|| process::Stdio::inherit()))
         .stdout(process::Stdio::inherit())
         .spawn()?;
     
@@ -71,10 +71,10 @@ pub fn run_single<F: ?Sized + AsRawFd>(file: &F, opt: args::ExecMode) -> io::Res
     
     match opt {
 	args::ExecMode::Positional { command, args } => {
-	    todo!("implement this with `proc_file(&file)`")
+	    run_stdin(None::<fs::File>, command, args.into_iter().map(move |x| x.unwrap_or_else(|| proc_file(&input).into())))
 	},
 	args::ExecMode::Stdin { command, args } => {
-	    run_stdin(input, command, args)
+	    run_stdin(Some(input), command, args)
 	}
     }
 }
@@ -83,13 +83,29 @@ 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<F: ?Sized + AsRawFd>(file: &F, opt: Options) -> io::Result<impl IntoIterator<Item = io::Result<process::Child> + 'static>>
+pub fn spawn_from<'a, F: ?Sized + AsRawFd>(file: &'a F, opt: Options) -> impl IntoIterator<Item = io::Result<process::Child>> + 'a
 {
-    todo!("Loop through `opt.into_exec()`, map the call to `|x| run_single(file, x)`, and return that iterator")
+    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")
 }
 
+/// Spawn all `-exec/{}` commands and wait for all children to complete.
+///
+/// # Returns
+/// An iterator of the result of spawning each child and its exit status.
 #[inline] 
-pub fn spawn_from<F: ?Sized + AsRawFd>(file: &F, opt: Options) -> io::Result<impl IntoIterator<Item = io::Result<i32> + 'static>>
+pub fn spawn_from_sync<'a, F: ?Sized + AsRawFd>(file: &'a F, opt: Options) -> impl IntoIterator<Item = io::Result<i32>> + 'a
 {
-    todo!("Map `spawn_from(...)` and wait for each child to terminate concurrently. Then return an iterator or the return codes or spawning errors for that now terminated child.")
+    spawn_from(file, opt).into_iter().map(move |child| -> io::Result<_> {
+	match child {
+	    Ok(mut child) => {
+		Ok(child.wait()?.code().unwrap_or(-1))
+	    },
+	    Err(err) => {
+		if_trace!(error!("Failed to spawn child: {err}"));
+		Err(err)
+	    }
+	}
+    })
+    //todo!("Map `spawn_from(...)` and wait for each child to terminate concurrently. Then return an iterator or the return codes or spawning errors for that now terminated child.")
 }

src/ext.rs

@@ -348,3 +348,72 @@ where F: FnOnce() -> T
 	}
     }
 }
+
+#[inline(always)] 
+pub(crate) fn map_bool<T>(ok: bool, value: T) -> T
+where T: Default
+{
+    if ok {
+	value
+    } else {
+	T::default()
+    }
+}
+pub trait SealExt
+{
+    fn try_seal(&self, shrink: bool, grow: bool, write: bool) -> io::Result<()>;
+
+    #[inline] 
+    fn sealed(self, shrink: bool, grow: bool, write: bool) -> Self
+    where Self: Sized {
+	if let Err(e) = self.try_seal(shrink, grow, write) {
+	    panic!("Failed to apply seals: {}", io::Error::last_os_error())
+	}
+	self
+    }
+}
+#[cfg(any(feature="memfile", feature="exec"))]
+const _: () = {
+    impl<T: AsRawFd + ?Sized> SealExt for T
+    {
+	#[cfg_attr(feature="logging", instrument(skip(self)))] 
+	fn sealed(self, shrink: bool, grow: bool, write: bool) -> Self
+	where Self: Sized {
+	    use libc::{
+		F_SEAL_GROW, F_SEAL_SHRINK, F_SEAL_WRITE,
+		F_ADD_SEALS,
+		fcntl
+	    };
+	    let fd = self.as_raw_fd();
+	    if unsafe {
+		fcntl(fd, F_ADD_SEALS
+		      , map_bool(shrink, F_SEAL_SHRINK)
+		      | map_bool(grow, F_SEAL_GROW)
+		      | map_bool(write, F_SEAL_WRITE))
+	    } < 0 {
+		panic!("Failed to apply seals to file descriptor {fd}: {}", io::Error::last_os_error())
+	    } 
+	    self	
+	}
+	
+	#[cfg_attr(feature="logging", instrument(skip(self), err))] 
+	fn try_seal(&self, shrink: bool, grow: bool, write: bool) -> io::Result<()> {
+	    use libc::{
+		F_SEAL_GROW, F_SEAL_SHRINK, F_SEAL_WRITE,
+		F_ADD_SEALS,
+		fcntl
+	    };
+	    let fd = self.as_raw_fd();
+	    if unsafe {
+		fcntl(fd, F_ADD_SEALS
+		      , map_bool(shrink, F_SEAL_SHRINK)
+		      | map_bool(grow, F_SEAL_GROW)
+		      | map_bool(write, F_SEAL_WRITE))
+	    } < 0 {
+		Err(io::Error::last_os_error())
+	    } else {
+		Ok(())
+	    }
+	}
+    }
+};

src/main.rs

@@ -1,3 +1,4 @@
+//#![feature(const_trait_impl)]
 
 #[macro_use] extern crate cfg_if;
 #[cfg(feature="logging")] 
@@ -32,8 +33,8 @@ macro_rules! if_trace {
 		$(
 		    #[cfg(not(feature="logging"))]
 		    let val = { $no };
-		    )?
-		val
+		)?
+		    val
 	    }
 	}
     };
@@ -170,6 +171,25 @@ fn feature_check() -> eyre::Result<()>
     Ok(())
 }
 
+#[inline] 
+fn try_seal_size<F: AsRawFd + ?Sized>(file: &F) -> eyre::Result<()>
+{
+    //if cfg!(feature="exec") {
+    if let Err(err) = file.try_seal(true,true,false)
+        .with_section(|| format!("Raw file descriptor: {}", file.as_raw_fd()).header("Attempted seal was on"))
+	.with_warning(|| "This may cause consumers of -exec{} to misbehave") {
+	    let fd = file.as_raw_fd();
+	    if_trace!{{
+		warn!("Failed to seal file descriptor {fd}: {err}");
+		eprintln!("\t{err:?}");
+	    }}
+	    Err(err).wrap_err("Failed to seal file's length")
+	} else {
+	    Ok(())
+	}
+    //}
+}
+
 mod work {
     use super::*;
     #[cfg_attr(feature="logging", instrument(err))]
@@ -467,6 +487,9 @@ mod work {
 	};
 	if_trace!(info!("collected {} from stdin. starting write.", read));
 
+	// Seal memfile
+	let _ = try_seal_size(&file);
+
 	// TODO: XXX: Currently causes crash. But if we can get this to work, leaving this in is definitely safe (as opposed to the pre-setting (see above.))
 	set_stdout_len(read)
 	    .wrap_err(eyre!("Failed to `ftruncate()` stdout after collection of {read} bytes"))
@@ -488,7 +511,7 @@ mod work {
     }
 }
 
-#[cfg_attr(feature="logging", instrument(err))]
+#[cfg_attr(feature="logging", instrument(err))] 
 #[inline(always)]
 unsafe fn close_raw_fileno(fd: RawFd) -> io::Result<()>
 {