From fe5b9016f515d5e3693478d45a397d3435efd2fd Mon Sep 17 00:00:00 2001
From: Dean Li <deantvv@gmail.com>
Date: Sat, 17 Apr 2021 19:12:52 +0800
Subject: [PATCH 1/3] os: Implement copy_file_range

Use `libc::copy_file_range`

Related to #1175
---
 vm/src/stdlib/os.rs | 46 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/vm/src/stdlib/os.rs b/vm/src/stdlib/os.rs
index b1550e946..d8f3577e0 100644
--- a/vm/src/stdlib/os.rs
+++ b/vm/src/stdlib/os.rs
@@ -1,3 +1,5 @@
+use std::convert::TryFrom;
+use std::convert::TryInto;
 use std::ffi;
 use std::fs::File;
 use std::fs::OpenOptions;
@@ -1195,6 +1197,50 @@ mod _os {
         }
     }
 
+    #[derive(FromArgs)]
+    struct CopyFileRangeArgs {
+        #[pyarg(positional)]
+        src: i32,
+        #[pyarg(positional)]
+        dst: i32,
+        #[pyarg(positional)]
+        count: i64,
+        #[pyarg(any, default)]
+        offset_src: Option<Offset>,
+        #[pyarg(any, default)]
+        offset_dst: Option<Offset>,
+    }
+
+    #[cfg(unix)]
+    #[pyfunction]
+    fn copy_file_range(args: CopyFileRangeArgs, vm: &VirtualMachine) -> PyResult<usize> {
+        let p_offset_src = args.offset_src.as_ref().map_or_else(std::ptr::null, |x| x);
+        let p_offset_dst = args.offset_dst.as_ref().map_or_else(std::ptr::null, |x| x);
+        let count: usize = args
+            .count
+            .try_into()
+            .map_err(|_| vm.new_value_error("count should > 0".to_string()))?;
+
+        // The flags argument is provided to allow
+        // for future extensions and currently must be to 0.
+        let flags = 0u32;
+
+        // Safety: p_offset_src and p_offset_dst is a unique pointer for offset_src and offset_dst respectively,
+        // and will only be freed after this function ends.
+        let ret = unsafe {
+            libc::copy_file_range(
+                args.src,
+                p_offset_src as *mut i64,
+                args.dst,
+                p_offset_dst as *mut i64,
+                count,
+                flags,
+            )
+        };
+
+        usize::try_from(ret).map_err(|_| vm.new_os_error("Fail to copy_file_range".to_string()))
+    }
+
     #[pyfunction]
     fn strerror(e: i32) -> String {
         unsafe { ffi::CStr::from_ptr(libc::strerror(e)) }

From f8ee3d7434027a578755b1facc1c1fc6ffd118cd Mon Sep 17 00:00:00 2001
From: Dean Li <deantvv@gmail.com>
Date: Sat, 17 Apr 2021 21:36:22 +0800
Subject: [PATCH 2/3] os: copy_file_range only support linux

---
 vm/src/stdlib/os.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/vm/src/stdlib/os.rs b/vm/src/stdlib/os.rs
index d8f3577e0..f4a2e58b8 100644
--- a/vm/src/stdlib/os.rs
+++ b/vm/src/stdlib/os.rs
@@ -1211,7 +1211,7 @@ mod _os {
         offset_dst: Option<Offset>,
     }
 
-    #[cfg(unix)]
+    #[cfg(target_os = "linux")]
     #[pyfunction]
     fn copy_file_range(args: CopyFileRangeArgs, vm: &VirtualMachine) -> PyResult<usize> {
         let p_offset_src = args.offset_src.as_ref().map_or_else(std::ptr::null, |x| x);

From 6fefadeb3956238dcc0be2154e0966722a91886a Mon Sep 17 00:00:00 2001
From: Dean Li <deantvv@gmail.com>
Date: Sun, 18 Apr 2021 09:30:42 +0800
Subject: [PATCH 3/3] os: Fix unused warning and propagate errno to user

---
 vm/src/stdlib/os.rs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/vm/src/stdlib/os.rs b/vm/src/stdlib/os.rs
index f4a2e58b8..01a3a2760 100644
--- a/vm/src/stdlib/os.rs
+++ b/vm/src/stdlib/os.rs
@@ -1,5 +1,3 @@
-use std::convert::TryFrom;
-use std::convert::TryInto;
 use std::ffi;
 use std::fs::File;
 use std::fs::OpenOptions;
@@ -1197,6 +1195,7 @@ mod _os {
         }
     }
 
+    #[cfg(target_os = "linux")]
     #[derive(FromArgs)]
     struct CopyFileRangeArgs {
         #[pyarg(positional)]
@@ -1214,12 +1213,13 @@ mod _os {
     #[cfg(target_os = "linux")]
     #[pyfunction]
     fn copy_file_range(args: CopyFileRangeArgs, vm: &VirtualMachine) -> PyResult<usize> {
+        use std::convert::{TryFrom, TryInto};
         let p_offset_src = args.offset_src.as_ref().map_or_else(std::ptr::null, |x| x);
         let p_offset_dst = args.offset_dst.as_ref().map_or_else(std::ptr::null, |x| x);
         let count: usize = args
             .count
             .try_into()
-            .map_err(|_| vm.new_value_error("count should > 0".to_string()))?;
+            .map_err(|_| vm.new_value_error("count should >= 0".to_string()))?;
 
         // The flags argument is provided to allow
         // for future extensions and currently must be to 0.
@@ -1238,7 +1238,7 @@ mod _os {
             )
         };
 
-        usize::try_from(ret).map_err(|_| vm.new_os_error("Fail to copy_file_range".to_string()))
+        usize::try_from(ret).map_err(|_| errno_err(vm))
     }
 
     #[pyfunction]