Improve UEFI fs

1. Implement copy
2. Fix copying cross device

Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>

Author: Ayush1325

library/std/src/sys/uefi/fs.rs

@@ -400,12 +400,19 @@ pub fn rename(old: &Path, new: &Path) -> io::Result<()> {
     let open_mode = file::MODE_READ | file::MODE_WRITE;
     let file = uefi_fs::FileProtocol::from_path(old, open_mode, 0)?;
 
-    // Delete if new already exists
-    if let Ok(f) = uefi_fs::FileProtocol::from_path(new, open_mode, 0) {
-        f.delete()?;
+    // If tbe device prefix is same or both path are relative (in which case None will be
+    // returned), then we can just use `set_file_name`.
+    if super::path::device_prefix(old.as_os_str()) == super::path::device_prefix(new.as_os_str()) {
+        // Delete if new already exists
+        if let Ok(f) = uefi_fs::FileProtocol::from_path(new, open_mode, 0) {
+            f.delete()?;
+        }
+        file.set_file_name(new.as_os_str())
+    } else {
+        // Use simple copy if the new path is in a different device.
+        copy(old, new)?;
+        file.delete()
     }
-
-    file.set_file_name(new.as_os_str())
 }
 
 pub fn set_perm(p: &Path, perm: FilePermissions) -> io::Result<()> {
@@ -475,9 +482,23 @@ pub fn canonicalize(_p: &Path) -> io::Result<PathBuf> {
     unsupported()
 }
 
-// FIXME: Find an efficient implementation
-pub fn copy(_from: &Path, _to: &Path) -> io::Result<u64> {
-    unsupported()
+pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
+    let from_file = uefi_fs::FileProtocol::from_path(from, file::MODE_READ, 0)?;
+    let to_file = uefi_fs::FileProtocol::from_path(
+        to,
+        file::MODE_READ | file::MODE_WRITE | file::MODE_CREATE,
+        0,
+    )?;
+    // Truncate destination file.
+    to_file.set_file_size(0)?;
+
+    let info = from_file.get_file_info()?;
+    let file_size = unsafe { (*info.as_ptr()).file_size };
+    let mut buffer = Vec::<u8>::with_capacity(file_size as usize);
+    let mut buffer_size = buffer.capacity();
+    from_file.read(&mut buffer, &mut buffer_size)?;
+    unsafe { buffer.set_len(buffer_size) };
+    Ok(to_file.write(&buffer)? as u64)
 }
 
 // Liberal Cascade Delete

library/std/src/sys/uefi/os.rs

@@ -10,7 +10,7 @@ use crate::os::uefi;
 use crate::path::{self, PathBuf};
 use crate::{error::Error as StdError, os::uefi::ffi::OsStringExt};
 
-// Return EFI_ABORTED as Status
+// Return EFI_SUCCESS as Status
 pub fn errno() -> i32 {
     r_efi::efi::Status::SUCCESS.as_usize() as i32
 }
@@ -169,7 +169,7 @@ pub fn unsetenv(key: &OsStr) -> io::Result<()> {
 }
 
 pub fn temp_dir() -> PathBuf {
-    panic!("no filesystem on this platform")
+    panic!("no supported on this platform")
 }
 
 pub fn home_dir() -> Option<PathBuf> {

library/std/src/sys/uefi/time.rs

@@ -123,6 +123,9 @@ impl From<r_efi::system::Time> for SystemTime {
 
 // FIXME: Don't know how to use Daylight Saving thing
 fn uefi_time_to_duration(t: r_efi::system::Time) -> Duration {
+    assert!(t.month <= 12);
+    assert!(t.month != 0);
+
     const MONTH_DAYS: [u64; 12] = [0, 31, 59, 90, 120, 151, 181, 211, 242, 272, 303, 333];
 
     let localtime_epoch: u64 = u64::from(t.year - 1970) * SEC_IN_YEAR

library/std/src/time.rs

@@ -114,7 +114,7 @@ pub use core::time::TryFromFloatSecsError;
 /// | SOLID     | `get_tim`                                                            |
 /// | WASI      | [__wasi_clock_time_get (Monotonic Clock)]                            |
 /// | Windows   | [QueryPerformanceCounter]                                            |
-/// | UEFI      | EFI_RUNTIME_SERVICES->GetTime()                                      |
+/// | UEFI      | EFI_TIMESTAMP_PROTOCOL->GetTimestamp()                               |
 ///
 /// [currently]: crate::io#platform-specific-behavior
 /// [QueryPerformanceCounter]: https://docs.microsoft.com/en-us/windows/win32/api/profileapi/nf-profileapi-queryperformancecounter