Emerald: Implemented File::seek

Author: Amjad50

Cargo.lock

@@ -1212,15 +1212,15 @@ dependencies = [
 
 [[package]]
 name = "emerald_kernel_user_link"
-version = "0.2.4"
+version = "0.2.7"
 dependencies = [
  "compiler_builtins",
  "rustc-std-workspace-core",
 ]
 
 [[package]]
 name = "emerald_std"
-version = "0.2.7"
+version = "0.2.8"
 dependencies = [
  "compiler_builtins",
  "emerald_kernel_user_link",

library/std/Cargo.toml

@@ -61,7 +61,7 @@ r-efi-alloc = { version = "1.0.0", features = ['rustc-dep-of-std'] }
 # This is from `https://github.com/Amjad50/Emerald`, i.e. it must be run from that context
 # TODO: for now we are using relative path, as we are using `libm` from `git` and we can't publish
 #       that. Fix it later
-emerald_std = { version = "0.2.5", features = ['rustc-dep-of-std'], path = "../../../../libraries/emerald_std" }
+emerald_std = { version = "0.2.8", features = ['rustc-dep-of-std'], path = "../../../../libraries/emerald_std" }
 
 [features]
 backtrace = [

library/std/src/sys/pal/emerald/fs.rs

@@ -1,6 +1,6 @@
 use core::ffi::CStr;
 
-use emerald_std::io::FileStat;
+use emerald_std::io::{FileStat, SeekWhence};
 
 use crate::ffi::OsString;
 use crate::fmt;
@@ -300,8 +300,20 @@ impl File {
         Ok(())
     }
 
-    pub fn seek(&self, _pos: SeekFrom) -> io::Result<u64> {
-        todo!()
+    pub fn seek(&self, pos: SeekFrom) -> io::Result<u64> {
+        let (whence, offset) = match pos {
+            // Casting to `i64` is fine, too large values will end up as
+            // negative which will cause an error in `sys_seek`.
+            SeekFrom::Start(off) => (SeekWhence::Start, off as i64),
+            SeekFrom::Current(off) => (SeekWhence::Current, off),
+            SeekFrom::End(off) => (SeekWhence::End, off),
+        };
+
+        let seek = emerald_std::io::SeekFrom { whence, offset };
+
+        unsafe {
+            emerald_std::io::syscall_seek(self.fd.as_raw_fd(), seek).map_err(syscall_to_io_error)
+        }
     }
 
     pub fn duplicate(&self) -> io::Result<File> {