From 6f4bf91a25c340d40f647a6de371bfd076c1ac39 Mon Sep 17 00:00:00 2001
From: pjht <pterpstra@pterpstra.com>
Date: Mon, 30 Sep 2024 13:32:54 -0500
Subject: [PATCH] Add seek function

---
 Cargo.lock  |  9 ++++++--
 Cargo.toml  |  1 +
 src/main.rs | 60 +++++++++++++++++++++++++++++++++++++++++++++--------
 3 files changed, 59 insertions(+), 11 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index b0d64e8..5fe8de3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -19,9 +19,12 @@ checksum = "0c4b4d0bd25bd0b74681c0ad21497610ce1b7c91b1022cd21c80c6fbdd9476b0"
 
 [[package]]
 name = "bitflags"
-version = "2.5.0"
+version = "2.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf4b9d6a944f767f8e5e0db018570623c85f3d925ac718db4e06d0187adb21c1"
+checksum = "b048fb63fd8b5923fc5aa7b340d8e156aec7ec02f0c78fa8a6ddc2613f6f71de"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "byteorder"
@@ -95,6 +98,7 @@ checksum = "ef1a6892d9eef45c8fa6b9e0086428a2cca8491aca8f787c534a3d6d0bcb3ced"
 name = "file_rpc"
 version = "0.1.0"
 dependencies = [
+ "bitflags",
  "parking_lot",
  "postcard",
  "serde",
@@ -130,6 +134,7 @@ dependencies = [
  "dev_driver_rpc",
  "devfs_rpc",
  "file_rpc",
+ "parking_lot",
 ]
 
 [[package]]
diff --git a/Cargo.toml b/Cargo.toml
index ff7d892..eaf8216 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,7 @@ edition = "2021"
 dev_driver_rpc = { version = "0.1.0", path = "../dev_driver_rpc" }
 devfs_rpc = { version = "0.1.0", path = "../devfs/devfs_rpc" }
 file_rpc = { version = "0.1.0", path = "../file_rpc" }
+parking_lot = "0.12.3"
 
 [profile.release]
 strip = true
diff --git a/src/main.rs b/src/main.rs
index 7087c29..94ae37a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,27 +1,34 @@
-use std::{borrow::Cow, os::mikros::{ipc, syscalls::{self, get_initrd}}};
+use std::{borrow::Cow, os::mikros::{ipc, syscalls::{self, get_initrd}}, sync::Arc};
 
+use parking_lot::RwLock;
+
+#[derive(Clone)]
 struct Serv {
-    initrd: &'static [u8]
+    initrd: &'static [u8],
+    files: Arc<RwLock<Vec<u64>>>,
 }
 
 impl dev_driver_rpc::Server for Serv {
     fn open(&self, _path: &std::path::Path) -> Result<u64, ()> {
-        Ok(0)
+        let mut files = self.files.write();
+        files.push(0);
+        Ok((files.len() - 1) as u64)
     }
 }
 
 impl file_rpc::Server for Serv {
-    fn read(&self, _fd: u64, pos: u64, len: usize) -> Result<Cow<'_, [u8]>, ()> {
+    fn read(&self, fd: u64, len: usize) -> Result<Cow<'_, [u8]>, ()> {
+        let pos = self.files.read()[fd as usize];
         if pos as usize >= self.initrd.len() {
             return Err(())
         }
         let avail_bytes = self.initrd.len() - pos as usize;
         let read_len = usize::min(len, avail_bytes);
+        self.files.write()[fd as usize] += read_len as u64;
         Ok(self.initrd[(pos as usize)..((pos as usize)+read_len)].into())
     }
 
-    fn write(&self, _fd: u64, _pos: u64, data: &[u8]) -> Result<(), ()> {
-        print!("{}", std::str::from_utf8(data).map_err(|_| ())?);
+    fn write(&self, _fd: u64, _data: &[u8]) -> Result<(), ()> {
         Ok(())
     }
 
@@ -33,14 +40,49 @@ impl file_rpc::Server for Serv {
     }
 
     fn dup(&self, fd: u64) -> Option<u64> {
-        Some(fd)
+        let mut files = self.files.write();
+        let file = files[fd as usize];
+        files.push(file);
+        Some((files.len() - 1) as u64)
+    }
+
+    fn seek(&self, fd: u64, pos: file_rpc::SeekFrom) -> u64 {
+        let mut files = self.files.write();
+        let file_pos = &mut files[fd as usize];
+        match pos {
+            file_rpc::SeekFrom::Start(offset) => {
+                *file_pos = offset;
+            },
+            file_rpc::SeekFrom::End(offset) => {
+                if offset <= 0 {
+                    *file_pos = self.initrd.len() as u64 - (-offset) as u64;
+                }
+            },
+            file_rpc::SeekFrom::Current(offset) => {
+                if offset > 0 {
+                    *file_pos = u64::min(*file_pos + offset as u64, self.initrd.len() as u64);
+                } else {
+                    let offset = (-offset) as u64;
+                    if offset > *file_pos {
+                        *file_pos = 0;
+                    } else {
+                        *file_pos -= offset;
+                    }
+                }
+            },
+        }
+        *file_pos
     }
 }
 
 fn main() {
     let initrd = get_initrd();
-    dev_driver_rpc::register_server(Box::new(Serv {initrd}));
-    file_rpc::register_server(Box::new(Serv {initrd}));
+    let serv = Serv {
+        initrd,
+        files: Arc::new(RwLock::new(Vec::new())),
+    };
+    dev_driver_rpc::register_server(Box::new(serv.clone()));
+    file_rpc::register_server(Box::new(serv));
     let devfs_pid;
     loop {
         if let Some(pid) = syscalls::try_get_registered(1) {