From 95f4fed4e273b50618f81cdffb23088cada87e0e Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Mon, 19 Jan 2026 12:39:59 -0700
Subject: [PATCH] Implement fscall RFC

---
 Cargo.toml      |  2 +-
 src/call.rs     |  6 +++++-
 src/data.rs     | 45 ++++++++++++++++++++++++++++++++++++++++++++-
 src/flag.rs     | 45 +++++++++++++++++++++++++++++++++++++++++++++
 src/schemev2.rs |  2 ++
 5 files changed, 97 insertions(+), 3 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index a761213f2c..ff68b189a1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "redox_syscall"
-version = "0.7.0"
+version = "0.7.1"
 description = "A Rust library to access raw Redox system calls"
 license = "MIT"
 authors = ["Jeremy Soller <jackpot51@gmail.com>"]
diff --git a/src/call.rs b/src/call.rs
index 3fbc98673c..b7a421ad14 100644
--- a/src/call.rs
+++ b/src/call.rs
@@ -1,6 +1,6 @@
 use super::{
     arch::*,
-    data::{Map, Stat, StatVfs, TimeSpec},
+    data::{Map, Stat, StatVfs, StdFsCallMeta, TimeSpec},
     error::Result,
     flag::*,
     number::*,
@@ -344,3 +344,7 @@ pub fn call_rw(fd: usize, payload: &mut [u8], flags: CallFlags, metadata: &[u64]
         )
     }
 }
+
+pub fn std_fs_call(fd: usize, payload: &mut [u8], metadata: &StdFsCallMeta) -> Result<usize> {
+    call_rw(fd, payload, CallFlags::STD_FS, metadata)
+}
diff --git a/src/data.rs b/src/data.rs
index 746f87ef4b..cfa9bee2c9 100644
--- a/src/data.rs
+++ b/src/data.rs
@@ -4,7 +4,7 @@ use core::{
     slice,
 };
 
-use crate::flag::{EventFlags, MapFlags, PtraceFlags};
+use crate::flag::{EventFlags, MapFlags, PtraceFlags, StdFsCallKind};
 
 #[derive(Copy, Clone, Debug, Default)]
 #[repr(C)]
@@ -174,6 +174,49 @@ impl DerefMut for StatVfs {
     }
 }
 
+#[derive(Copy, Clone, Debug, Default, PartialEq)]
+#[repr(C, packed)]
+pub struct StdFsCallMeta {
+    pub kind: u8, // enum StdFsCallKind
+    _rsvd: [u8; 7],
+    pub arg1: u64,
+    pub arg2: u64,
+}
+
+impl StdFsCallMeta {
+    pub fn new(kind: StdFsCallKind, arg1: u64, arg2: u64) -> Self {
+        Self {
+            kind: kind as u8,
+            _rsvd: [0; 7],
+            arg1,
+            arg2,
+        }
+    }
+}
+
+impl Deref for StdFsCallMeta {
+    type Target = [u64];
+    fn deref(&self) -> &[u64] {
+        unsafe {
+            slice::from_raw_parts(
+                self as *const StdFsCallMeta as *const u64,
+                mem::size_of::<StdFsCallMeta>() / mem::size_of::<u64>(),
+            )
+        }
+    }
+}
+
+impl DerefMut for StdFsCallMeta {
+    fn deref_mut(&mut self) -> &mut [u64] {
+        unsafe {
+            slice::from_raw_parts_mut(
+                self as *mut StdFsCallMeta as *mut u64,
+                mem::size_of::<StdFsCallMeta>() / mem::size_of::<u64>(),
+            )
+        }
+    }
+}
+
 #[derive(Copy, Clone, Debug, Default, PartialEq)]
 #[repr(C)]
 pub struct TimeSpec {
diff --git a/src/flag.rs b/src/flag.rs
index e0cc36d8e5..51f827a537 100644
--- a/src/flag.rs
+++ b/src/flag.rs
@@ -402,6 +402,51 @@ bitflags! {
         const FD_CLONE = 1 << 13;
         const FD_UPPER = 1 << 14;
         const FD_CLOEXEC = 1 << 15;
+
+        /// Call is a standard fs call, with metadata defined in `StdFsCallMeta`
+        const STD_FS = 1 << 16;
+    }
+}
+
+#[repr(u8)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub enum StdFsCallKind {
+    /*TODO: remove old syscalls
+    Fchmod = 1,
+    Fchown = 2,
+    Getdents = 3,
+    Fstat = 4,
+    Fstatvfs = 5,
+    Fsync = 6,
+    Ftruncate = 7,
+    Futimens = 8,
+    // 9 reserved in fscall RFC
+    Unlinkat = 10,
+    */
+    Realpathat = 11,
+}
+
+impl StdFsCallKind {
+    pub fn try_from_raw(raw: u8) -> Option<Self> {
+        use StdFsCallKind::*;
+
+        // TODO: Use a library where this match can be automated.
+        Some(match raw {
+            /*
+            1 => Fchmod,
+            2 => Fchown,
+            3 => Getdents,
+            4 => Fstat,
+            5 => Fstatvfs,
+            6 => Fsync,
+            7 => Ftruncate,
+            8 => Futimens,
+            // 9 reserved in fscall RFC
+            10 => Unlinkat,
+            */
+            11 => Realpathat,
+            _ => return None,
+        })
     }
 }
 
diff --git a/src/schemev2.rs b/src/schemev2.rs
index 54dc9378db..38bcd8c5c6 100644
--- a/src/schemev2.rs
+++ b/src/schemev2.rs
@@ -145,6 +145,7 @@ pub enum Opcode {
     Recvfd = 31,
 
     UnlinkAt = 32, // fd, path_ptr, path_len (utf8), flags
+    StdFsCall = 33,
 }
 
 impl Opcode {
@@ -187,6 +188,7 @@ impl Opcode {
             31 => Recvfd,
 
             32 => UnlinkAt,
+            33 => StdFsCall,
 
             _ => return None,
         })