vfs/user: implement chmod utility

kernel/libk/src/vfs/node/ops.rs

@@ -3,7 +3,10 @@ use core::mem::MaybeUninit;
 use libk_util::ext::OptionExt;
 use yggdrasil_abi::{
     error::Error,
-    io::{DirectoryEntry, FileMode, GroupId, OpenOptions, UserId},
+    io::{
+        DirectoryEntry, FileMetadataUpdate, FileMetadataUpdateMode, FileMode, GroupId, OpenOptions,
+        UserId,
+    },
 };
 
 use crate::vfs::{
@@ -263,6 +266,34 @@ impl Node {
         Ok(*metadata)
     }
 
+    pub fn update_metadata(self: &NodeRef, update: &FileMetadataUpdate) -> Result<(), Error> {
+        let FileMetadataUpdate::Permissions(mode) = update else {
+            return Err(Error::NotImplemented);
+        };
+
+        let mut cache = self.props.lock();
+        let common = self.data_as_common();
+
+        let metadata = cache
+            .metadata
+            .get_or_try_insert_with(|| common.metadata(self))?;
+
+        match *mode {
+            FileMetadataUpdateMode::Set(value) => metadata.mode |= value,
+            FileMetadataUpdateMode::Modify { set, clear } => {
+                metadata.mode &= !clear;
+                metadata.mode |= set;
+            }
+        }
+
+        if !self.flags.contains(NodeFlags::IN_MEMORY_PROPS) {
+            // Update permissions in the real node
+            common.set_metadata(self, metadata)?;
+        }
+
+        Ok(())
+    }
+
     // TODO clarify directory size
     /// Returns the size in bytes of the node
     pub fn size(self: &NodeRef) -> Result<u64, Error> {

kernel/src/syscall/imp/sys_io.rs

@@ -235,14 +235,22 @@ pub(crate) fn clone_fd(source_fd: RawFd, target_fd: Option<RawFd>) -> Result<Raw
 
 pub(crate) fn update_metadata(
     at: Option<RawFd>,
-    _path: &str,
+    path: &str,
-    _update: &FileMetadataUpdate,
+    update: &FileMetadataUpdate,
 ) -> Result<(), Error> {
     let thread = Thread::current();
     let process = thread.process();
 
-    run_with_io_at(&process, at, |_at, _io| {
+    run_with_io_at(&process, at, |at, mut io| {
-        todo!();
+        let node = if path.is_empty() {
+            at
+        } else {
+            io.ioctx_mut().find(Some(at), path, false)?
+        };
+
+        node.update_metadata(update)?;
+
+        Ok(())
     })
 }
 

lib/abi/src/io/file.rs

@@ -9,14 +9,15 @@ use super::FileMode;
 /// Describes an operation to perform when updating certain file metadata elements
 #[derive(Debug, Clone)]
 pub enum FileMetadataUpdateMode {
-    /// value = new
+    /// Assign a new file mode
-    Set,
+    Set(FileMode),
-    /// value = old | new
+    /// Set and/or clear existing file mode bits
-    Or,
+    Modify {
-    /// value = old & new
+        /// Bits to set
-    And,
+        set: FileMode,
-    /// value = old & !new
+        /// Bits to clear
-    AndNot,
+        clear: FileMode,
+    },
 }
 
 /// Describes how file times are updated
@@ -34,7 +35,7 @@ pub struct FileTimesUpdate {
 #[derive(Debug, Clone)]
 pub enum FileMetadataUpdate {
     /// Changes file permissions
-    Permissions(FileMode, FileMetadataUpdateMode),
+    Permissions(FileMetadataUpdateMode),
     /// Changes file mtime/atime/ctime
     Times(FileTimesUpdate),
 }

userspace/Cargo.lock

@@ -536,6 +536,7 @@ checksum = "790eea4361631c5e7d22598ecd5723ff611904e3344ce8720784c93e3d83d40b"
 name = "cross"
 version = "0.1.0"
 dependencies = [
+ "bitflags 2.8.0",
  "libc",
  "runtime",
  "tempfile",

userspace/Cargo.toml

@@ -31,6 +31,7 @@ clap = { version = "4.5.20", features = ["std", "derive", "help", "usage"], defa
 clap-num = "1.1.1"
 serde_json = "1.0.132"
 serde = { version = "1.0.214", features = ["derive"] }
+bitflags = "2.6.0"
 bytemuck = "1.19.0"
 thiserror = "1.0.64"
 env_logger = "0.11.5"

userspace/lib/cross/Cargo.toml

@@ -4,6 +4,7 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+bitflags.workspace = true
 
 [target.'cfg(target_os = "yggdrasil")'.dependencies]
 yggdrasil-rt.workspace = true

userspace/lib/cross/src/fs.rs

@@ -0,0 +1,46 @@
+use std::{fmt, io, os::fd::RawFd, path::Path};
+
+use bitflags::bitflags;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum FileModeUpdate {
+    Set(FileMode),
+    Modify { set: FileMode, clear: FileMode },
+}
+
+bitflags! {
+    #[derive(Clone, Copy, PartialEq, Eq)]
+    pub struct FileMode: u32 {
+        const OTHER_EXEC = 1 << 0;
+        const OTHER_WRITE = 1 << 1;
+        const OTHER_READ = 1 << 2;
+        const GROUP_EXEC = 1 << 3;
+        const GROUP_WRITE = 1 << 4;
+        const GROUP_READ = 1 << 5;
+        const USER_EXEC = 1 << 6;
+        const USER_WRITE = 1 << 7;
+        const USER_READ = 1 << 8;
+    }
+}
+
+impl FileMode {
+    const MASK: u32 = 0o777;
+}
+
+impl From<u32> for FileMode {
+    fn from(value: u32) -> Self {
+        Self::from_bits_retain(value & Self::MASK)
+    }
+}
+
+pub use crate::sys::fs::update_file_mode;
+
+pub fn set_file_mode<P: AsRef<Path>>(at: Option<RawFd>, path: P, mode: FileMode) -> io::Result<()> {
+    update_file_mode(at, path, FileModeUpdate::Set(mode))
+}
+
+impl fmt::Debug for FileMode {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{:#03o}", self.bits())
+    }
+}

userspace/lib/cross/src/lib.rs

@@ -3,7 +3,8 @@
 
 pub(crate) mod sys;
 
+pub mod fs;
 pub mod io;
-pub mod net;
 pub mod mem;
+pub mod net;
 pub mod signal;

userspace/lib/cross/src/sys/yggdrasil/fs.rs

@@ -0,0 +1,37 @@
+use std::{io, os::fd::RawFd, path::Path};
+
+use runtime::rt as yggdrasil_rt;
+use yggdrasil_rt::io::{FileMetadataUpdate, FileMetadataUpdateMode, FileMode as RawFileMode};
+
+use crate::fs::FileModeUpdate;
+
+pub fn update_file_mode<P: AsRef<Path>>(
+    at: Option<RawFd>,
+    path: P,
+    mode: FileModeUpdate,
+) -> io::Result<()> {
+    // TODO make a soft error?
+    let path_str = path.as_ref().to_str().expect("Path is not a valid string");
+    let raw_update_mode = match mode {
+        FileModeUpdate::Set(mode) => {
+            let raw_file_mode = unsafe { RawFileMode::from_raw(mode.bits()) };
+            FileMetadataUpdateMode::Set(raw_file_mode)
+        }
+        FileModeUpdate::Modify { set, clear } => {
+            let raw_set_mode = unsafe { RawFileMode::from_raw(set.bits()) };
+            let raw_clear_mode = unsafe { RawFileMode::from_raw(clear.bits()) };
+            FileMetadataUpdateMode::Modify {
+                set: raw_set_mode,
+                clear: raw_clear_mode,
+            }
+        }
+    };
+    unsafe {
+        yggdrasil_rt::sys::update_metadata(
+            at,
+            path_str,
+            &FileMetadataUpdate::Permissions(raw_update_mode),
+        )
+        .map_err(io::Error::from)
+    }
+}

userspace/lib/cross/src/sys/yggdrasil/mod.rs

@@ -1,3 +1,4 @@
+pub mod fs;
 pub mod mem;
 pub mod pid;
 pub mod pipe;

userspace/sysutils/src/chmod.rs

@@ -1,22 +1,96 @@
-#![feature(rustc_private, yggdrasil_os)]
+#![feature(iter_chain)]
-use std::{
+use std::{env, iter, process::ExitCode};
-    env,
-    os::yggdrasil::io::{self, FileMetadataUpdate, FileMetadataUpdateMode, RawFileMode},
-};
 
-fn main() {
+use cross::fs::{update_file_mode, FileMode, FileModeUpdate};
-    let args: Vec<_> = env::args().collect();
+
-    if args.len() != 3 {
+fn parse_delta_bit(
-        panic!();
+    bit: &str,
+    set: &mut FileMode,
+    clear: &mut FileMode,
+) -> Result<(), &'static str> {
+    let chars = bit.as_bytes();
+    let (target, plus_or_minus, bit) = match chars.len() {
+        2 => (b'a', chars[0], chars[1]),
+        3 => (chars[0], chars[1], chars[2]),
+        _ => return Err("Expected mode to be in format X[+-]Y or [+-]Y"),
+    };
+    let (add_in, remove_in) = match plus_or_minus {
+        b'+' => (set, clear),
+        b'-' => (clear, set),
+        _ => return Err("Expected +/- sign"),
+    };
+    let mask = match (target, bit) {
+        (b'a', b'r') => FileMode::USER_READ | FileMode::GROUP_READ | FileMode::OTHER_READ,
+        (b'a', b'w') => FileMode::USER_WRITE | FileMode::GROUP_WRITE | FileMode::OTHER_WRITE,
+        (b'a', b'x') => FileMode::USER_EXEC | FileMode::GROUP_EXEC | FileMode::OTHER_EXEC,
+        (b'u', b'r') => FileMode::USER_READ,
+        (b'u', b'w') => FileMode::USER_WRITE,
+        (b'u', b'x') => FileMode::USER_EXEC,
+        (b'g', b'r') => FileMode::GROUP_READ,
+        (b'g', b'w') => FileMode::GROUP_WRITE,
+        (b'g', b'x') => FileMode::GROUP_EXEC,
+        (b'o', b'r') => FileMode::OTHER_READ,
+        (b'o', b'w') => FileMode::OTHER_WRITE,
+        (b'o', b'x') => FileMode::OTHER_EXEC,
+        (_, _) => return Err("Invalid mode value"),
+    };
+
+    *add_in |= mask;
+    *remove_in &= !mask;
+
+    Ok(())
+}
+
+fn parse_mode_update(text: &str) -> Result<FileModeUpdate, &'static str> {
+    if let Some(digits) = text.strip_prefix("0") {
+        // Decode as absolute octal
+        let bits = u32::from_str_radix(digits, 8).map_err(|_| "Expected octal permission mask")?;
+        Ok(FileModeUpdate::Set(FileMode::from(bits)))
+    } else {
+        let mut set = FileMode::empty();
+        let mut clear = FileMode::empty();
+        // Try to decode as a sequence of +x,-y,+z... flags
+        for bit in text.split(',') {
+            parse_delta_bit(bit.trim_matches(',').trim(), &mut set, &mut clear)?;
         }
 
-    let mode_str = &args[1];
+        Ok(FileModeUpdate::Modify { set, clear })
-    let filename = &args[2];
+    }
-
+}
-    let mode_oct = u32::from_str_radix(mode_str, 8).unwrap();
+
-
+fn usage(invocation: &str) {
-    let update =
+    eprintln!("Usage: {invocation} OCT-MODE FILENAME [FILENAME...]");
-        FileMetadataUpdate::Permissions(RawFileMode::new(mode_oct), FileMetadataUpdateMode::Set);
+    eprintln!("    OR {invocation} [ugoa][+-][rwx] FILENAME [FILENAME...]");
-
+}
-    io::update_metadata(filename, &update).unwrap();
+
+fn run<I: Iterator<Item = String>>(mut args: I) -> Result<ExitCode, &'static str> {
+    let mode_str = args.next().ok_or("Too few arguments")?;
+    let first = args.next().ok_or("No filenames provided")?;
+    let args = iter::chain(iter::once(first), args);
+    let mode = parse_mode_update(&mode_str)?;
+
+    let mut code = ExitCode::SUCCESS;
+    for arg in args {
+        match update_file_mode(None, &arg, mode) {
+            Ok(()) => (),
+            Err(error) => {
+                eprintln!("{arg}: {error}");
+                code = ExitCode::FAILURE;
+            }
+        }
+    }
+    Ok(code)
+}
+
+fn main() -> ExitCode {
+    let mut args = env::args();
+    let invocation = args.next().unwrap();
+    match run(args) {
+        Ok(code) => code,
+        Err(usage_error) => {
+            eprintln!("{invocation}: {usage_error}");
+            usage(&invocation);
+            ExitCode::FAILURE
+        }
+    }
 }

userspace/tools/shell/src/syntax/lex.rs

@@ -141,7 +141,7 @@ fn lex_identifier(i: &str) -> IResult<&str, &str> {
     recognize(many1_count(alt((alphanumeric1, is_a("-_")))))(i)
 }
 fn lex_filename(i: &str) -> IResult<&str, &str> {
-    recognize(many1_count(alt((alphanumeric1, is_a("./-_:+")))))(i)
+    recognize(many1_count(alt((alphanumeric1, is_a("./-_:+,")))))(i)
 }
 
 fn lex_braced_var(i: &str) -> IResult<&str, &str> {