From 8b39059da8a8f3d58695ad62de869fb9c0973383 Mon Sep 17 00:00:00 2001
From: Mark Poliakov <mark@alnyan.me>
Date: Mon, 17 Jul 2023 22:54:43 +0300
Subject: [PATCH] alnyan/yggdrasil: add args implementation

---
 library/std/src/sys/yggdrasil/args.rs | 68 +++++++++++++++++++++++----
 library/std/src/sys/yggdrasil/mod.rs  |  3 +-
 2 files changed, 60 insertions(+), 11 deletions(-)

diff --git a/library/std/src/sys/yggdrasil/args.rs b/library/std/src/sys/yggdrasil/args.rs
index 02aae054769..d502e6c0264 100644
--- a/library/std/src/sys/yggdrasil/args.rs
+++ b/library/std/src/sys/yggdrasil/args.rs
@@ -1,10 +1,40 @@
 use crate::ffi::OsString;
 use crate::fmt;
+use crate::str::FromStr;
 
-pub struct Args(!);
+#[allow(dead_code)]
+#[derive(Clone, Copy)]
+pub struct Args {
+    base: usize,
+    len: usize,
+    index: usize,
+}
+
+// Argument structure layout:
+//
+// 0x000: args len
+// 0x008: arg ptr 0
+// 0x010: arg len 0
+// 0x018: arg ptr 1
+// 0x020: arg len 1
+// ...
+// .....: arg data 0
+// .....: arg data 1
+static mut ARGS: usize = 0;
 
 pub fn args() -> Args {
-    todo!()
+    let base = unsafe { ARGS };
+
+    if base == 0 {
+        panic!("Program arguments not initialized");
+    }
+
+    let len = unsafe {
+        #[allow(fuzzy_provenance_casts)]
+        (base as *mut usize).read()
+    };
+
+    Args { base, len, index: 0 }
 }
 
 impl fmt::Debug for Args {
@@ -17,17 +47,36 @@ impl Iterator for Args {
     type Item = OsString;
 
     fn next(&mut self) -> Option<Self::Item> {
-        todo!()
-    }
+        if self.index == self.len {
+            return None;
+        }
 
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        todo!()
+        let ptr_ptr_addr = self.base + (1 + self.index * 2) * 8;
+        let arg_ptr = unsafe {
+            #[allow(fuzzy_provenance_casts)]
+            (ptr_ptr_addr as *mut usize).read()
+        };
+        let arg_len = unsafe {
+            #[allow(fuzzy_provenance_casts)]
+            ((ptr_ptr_addr + 8) as *mut usize).read()
+        };
+
+        let slice = unsafe {
+            #[allow(fuzzy_provenance_casts)]
+            crate::slice::from_raw_parts(arg_ptr as *const u8, arg_len)
+        };
+        let arg_str = crate::str::from_utf8(slice).unwrap();
+        let arg_os_string = OsString::from_str(arg_str).unwrap();
+
+        self.index += 1;
+
+        Some(arg_os_string)
     }
 }
 
 impl ExactSizeIterator for Args {
     fn len(&self) -> usize {
-        todo!()
+        self.len
     }
 }
 
@@ -37,7 +86,6 @@ impl DoubleEndedIterator for Args {
     }
 }
 
-#[allow(dead_code)]
-pub unsafe fn init(_argc: isize, _argv: *const *const u8) {
-    todo!()
+pub unsafe fn init(program_arg: usize) {
+    ARGS = program_arg;
 }
diff --git a/library/std/src/sys/yggdrasil/mod.rs b/library/std/src/sys/yggdrasil/mod.rs
index 6e99d96aed4..f1655804286 100644
--- a/library/std/src/sys/yggdrasil/mod.rs
+++ b/library/std/src/sys/yggdrasil/mod.rs
@@ -99,7 +99,7 @@ pub fn unsupported() -> ! {
 
 #[cfg(not(test))]
 #[no_mangle]
-pub unsafe extern "C" fn runtime_entry(_arg: usize) -> ! {
+pub unsafe extern "C" fn runtime_entry(program_arg: usize) -> ! {
     use crate::ffi::c_char;
     use crate::ptr::null;
 
@@ -107,6 +107,7 @@ pub unsafe extern "C" fn runtime_entry(_arg: usize) -> ! {
         fn main(argc: isize, argv: *const *const c_char) -> i32;
     }
 
+    args::init(program_arg);
     let result = main(0, null());
 
     yggdrasil_rt::sys::exit(result);