From a5c02a3aa8a2a023e4630d687698abc9782debfb Mon Sep 17 00:00:00 2001
From: Mark Poliakov <mark@alnyan.me>
Date: Mon, 8 Jan 2024 18:44:27 +0200
Subject: [PATCH] Add C compatability fork()/execve()

---
 src/path/path.rs     | 22 ++++++++++++++++++++++
 src/path/path_buf.rs |  4 ++++
 src/process.rs       | 10 ++++++++++
 src/syscall.rs       |  9 +++++++++
 4 files changed, 45 insertions(+)

diff --git a/src/path/path.rs b/src/path/path.rs
index 40c3090b..c1621e0c 100644
--- a/src/path/path.rs
+++ b/src/path/path.rs
@@ -1,3 +1,7 @@
+use core::ffi::CStr;
+
+use crate::error::Error;
+
 #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
 #[repr(transparent)]
 pub struct Path(str);
@@ -15,6 +19,12 @@ impl Path {
         unsafe { core::mem::transmute(s) }
     }
 
+    pub fn from_c_str(s: &CStr) -> Result<&Self, Error> {
+        s.to_str()
+            .map_err(|_| Error::InvalidArgument)
+            .map(Path::from_str)
+    }
+
     pub fn empty() -> &'static Self {
         Self::from_str("")
     }
@@ -76,6 +86,11 @@ impl Path {
     pub fn as_ptr(&self) -> *const u8 {
         self.0.as_ptr()
     }
+
+    #[inline]
+    pub fn as_str(&self) -> &str {
+        &self.0
+    }
 }
 
 impl AsRef<str> for Path {
@@ -95,3 +110,10 @@ impl AsRef<Path> for str {
         Path::from_str(self)
     }
 }
+
+#[cfg(feature = "alloc")]
+impl AsRef<Path> for alloc::string::String {
+    fn as_ref(&self) -> &Path {
+        self.as_str().as_ref()
+    }
+}
diff --git a/src/path/path_buf.rs b/src/path/path_buf.rs
index 20a24fe9..d43c527f 100644
--- a/src/path/path_buf.rs
+++ b/src/path/path_buf.rs
@@ -21,6 +21,10 @@ impl PathBuf {
         todo!()
     }
 
+    pub fn join<P: AsRef<Path>>(&mut self, _path: P) -> Self {
+        todo!()
+    }
+
     pub fn display(&self) -> &str {
         self.0.as_str()
     }
diff --git a/src/process.rs b/src/process.rs
index 2e20f6d9..a663b7f2 100644
--- a/src/process.rs
+++ b/src/process.rs
@@ -68,6 +68,16 @@ pub struct SpawnOptions<'a> {
     pub optional: &'a [SpawnOption],
 }
 
+/// Legacy execve(2) arguments
+#[allow(missing_docs)]
+#[derive(Clone, Debug)]
+#[repr(C)]
+pub struct ExecveOptions<'a> {
+    pub program: &'a str,
+    pub arguments: &'a [&'a str],
+    pub environment: &'a [&'a str],
+}
+
 /// Controls how threads are spawned within a process
 #[derive(Clone, Debug)]
 #[repr(C)]
diff --git a/src/syscall.rs b/src/syscall.rs
index 9e5464a0..0cb604b9 100644
--- a/src/syscall.rs
+++ b/src/syscall.rs
@@ -56,6 +56,9 @@ primitive_enum!(
         #[doc = "Creates a pair of pseudo-terminal master/slave"]
         CreatePty = 24,
 
+        #[doc = "Clones a file descriptor"]
+        CloneFd = 25,
+
         #[doc = "Create and start a new process"]
         SpawnProcess = 40,
         #[doc = "Wait for a process to exit"]
@@ -86,6 +89,12 @@ primitive_enum!(
         #[doc = "Terminate the caller process"]
         ExitProcess = 54,
 
+        // C compat
+        #[doc = "Fork a process, creating an identical copy of its address space (C compat)"]
+        Fork = 55,
+        #[doc = "Replace the process address space with a new loaded program"]
+        Exec = 56,
+
         #[doc = "Mount a filesystem"]
         Mount = 101,
         #[doc = "Unmount a filesystem"]