diff --git a/library/std/src/os/unix/fs.rs b/library/std/src/os/unix/fs.rs index 3fc6cc44ce4..a0e664acd13 100644 --- a/library/std/src/os/unix/fs.rs +++ b/library/std/src/os/unix/fs.rs @@ -17,6 +17,10 @@ #[allow(unused_imports)] use io::{Read, Write}; +// Tests for this module +#[cfg(test)] +mod tests; + /// Unix-specific extensions to [`fs::File`]. #[stable(feature = "file_offset", since = "1.15.0")] pub trait FileExt { @@ -54,6 +58,16 @@ pub trait FileExt { #[stable(feature = "file_offset", since = "1.15.0")] fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result; + /// Like `read_at`, except that it reads into a slice of buffers. + /// + /// Data is copied to fill each buffer in order, with the final buffer + /// written to possibly being only partially filled. This method must behave + /// equivalently to a single call to read with concatenated buffers. + #[unstable(feature = "unix_file_vectored_at", issue = "89517")] + fn read_vectored_at(&self, bufs: &mut [io::IoSliceMut<'_>], offset: u64) -> io::Result { + io::default_read_vectored(|b| self.read_at(b, offset), bufs) + } + /// Reads the exact number of byte required to fill `buf` from the given offset. /// /// The offset is relative to the start of the file and thus independent @@ -155,6 +169,16 @@ fn read_exact_at(&self, mut buf: &mut [u8], mut offset: u64) -> io::Result<()> { #[stable(feature = "file_offset", since = "1.15.0")] fn write_at(&self, buf: &[u8], offset: u64) -> io::Result; + /// Like `write_at`, except that it writes from a slice of buffers. + /// + /// Data is copied from each buffer in order, with the final buffer read + /// from possibly being only partially consumed. This method must behave as + /// a call to `write_at` with the buffers concatenated would. + #[unstable(feature = "unix_file_vectored_at", issue = "89517")] + fn write_vectored_at(&self, bufs: &[io::IoSlice<'_>], offset: u64) -> io::Result { + io::default_write_vectored(|b| self.write_at(b, offset), bufs) + } + /// Attempts to write an entire buffer starting from a given offset. /// /// The offset is relative to the start of the file and thus independent @@ -218,9 +242,15 @@ impl FileExt for fs::File { fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result { self.as_inner().read_at(buf, offset) } + fn read_vectored_at(&self, bufs: &mut [io::IoSliceMut<'_>], offset: u64) -> io::Result { + self.as_inner().read_vectored_at(bufs, offset) + } fn write_at(&self, buf: &[u8], offset: u64) -> io::Result { self.as_inner().write_at(buf, offset) } + fn write_vectored_at(&self, bufs: &[io::IoSlice<'_>], offset: u64) -> io::Result { + self.as_inner().write_vectored_at(bufs, offset) + } } /// Unix-specific extensions to [`fs::Permissions`]. diff --git a/library/std/src/os/unix/fs/tests.rs b/library/std/src/os/unix/fs/tests.rs new file mode 100644 index 00000000000..67f607bd468 --- /dev/null +++ b/library/std/src/os/unix/fs/tests.rs @@ -0,0 +1,57 @@ +use super::*; + +#[test] +fn read_vectored_at() { + let msg = b"preadv is working!"; + let dir = crate::sys_common::io::test::tmpdir(); + + let filename = dir.join("preadv.txt"); + { + let mut file = fs::File::create(&filename).unwrap(); + file.write_all(msg).unwrap(); + } + { + let file = fs::File::open(&filename).unwrap(); + let mut buf0 = [0; 4]; + let mut buf1 = [0; 3]; + + let mut iovec = [io::IoSliceMut::new(&mut buf0), io::IoSliceMut::new(&mut buf1)]; + + let n = file.read_vectored_at(&mut iovec, 4).unwrap(); + + assert!(n == 4 || n == 7); + assert_eq!(&buf0, b"dv i"); + + if n == 7 { + assert_eq!(&buf1, b"s w"); + } + } +} + +#[test] +fn write_vectored_at() { + let msg = b"pwritev is not working!"; + let dir = crate::sys_common::io::test::tmpdir(); + + let filename = dir.join("preadv.txt"); + { + let mut file = fs::File::create(&filename).unwrap(); + file.write_all(msg).unwrap(); + } + let expected = { + let file = fs::File::options().write(true).open(&filename).unwrap(); + let buf0 = b" "; + let buf1 = b"great "; + + let iovec = [io::IoSlice::new(buf0), io::IoSlice::new(buf1)]; + + let n = file.write_vectored_at(&iovec, 11).unwrap(); + + assert!(n == 4 || n == 11); + + if n == 4 { b"pwritev is working!" } else { b"pwritev is great !" } + }; + + let content = fs::read(&filename).unwrap(); + assert_eq!(&content, expected); +} diff --git a/library/std/src/sys/unix/fd.rs b/library/std/src/sys/unix/fd.rs index 53523ca8c1d..9874af4d3e2 100644 --- a/library/std/src/sys/unix/fd.rs +++ b/library/std/src/sys/unix/fd.rs @@ -98,7 +98,7 @@ pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result { let ret = cvt(unsafe { libc::readv( self.as_raw_fd(), - bufs.as_ptr() as *const libc::iovec, + bufs.as_mut_ptr() as *mut libc::iovec as *const libc::iovec, cmp::min(bufs.len(), max_iov()) as libc::c_int, ) })?; @@ -107,7 +107,7 @@ pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result { #[cfg(any(target_os = "espidf", target_os = "horizon"))] pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result { - return crate::io::default_read_vectored(|b| self.read(b), bufs); + io::default_read_vectored(|b| self.read(b), bufs) } #[inline] @@ -153,6 +153,95 @@ pub fn read_buf(&self, mut cursor: BorrowedCursor<'_>) -> io::Result<()> { Ok(()) } + #[cfg(any( + target_os = "emscripten", + target_os = "freebsd", + target_os = "fuchsia", + target_os = "illumos", + target_os = "linux", + target_os = "netbsd", + ))] + pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result { + let ret = cvt(unsafe { + libc::preadv( + self.as_raw_fd(), + bufs.as_mut_ptr() as *mut libc::iovec as *const libc::iovec, + cmp::min(bufs.len(), max_iov()) as libc::c_int, + offset as _, + ) + })?; + Ok(ret as usize) + } + + #[cfg(not(any( + target_os = "android", + target_os = "emscripten", + target_os = "freebsd", + target_os = "fuchsia", + target_os = "illumos", + target_os = "ios", + target_os = "linux", + target_os = "macos", + target_os = "netbsd", + )))] + pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result { + io::default_read_vectored(|b| self.read_at(b, offset), bufs) + } + + // We support some old Android versions that do not have `preadv` in libc, + // so we use weak linkage and fallback to a direct syscall if not available. + // + // On 32-bit targets, we don't want to deal with weird ABI issues around + // passing 64-bits parameters to syscalls, so we fallback to the default + // implementation if `preadv` is not available. + #[cfg(all(target_os = "android", target_pointer_width = "64"))] + pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result { + super::weak::syscall! { + fn preadv( + fd: libc::c_int, + iovec: *const libc::iovec, + n_iovec: libc::c_int, + offset: off64_t + ) -> isize + } + + let ret = cvt(unsafe { + preadv( + self.as_raw_fd(), + bufs.as_mut_ptr() as *mut libc::iovec as *const libc::iovec, + cmp::min(bufs.len(), max_iov()) as libc::c_int, + offset as _, + ) + })?; + Ok(ret as usize) + } + + // We support old MacOS and iOS versions that do not have `preadv`. There is + // no `syscall` possible in these platform. + #[cfg(any( + all(target_os = "android", target_pointer_width = "32"), + target_os = "ios", + target_os = "macos", + ))] + pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result { + super::weak::weak!(fn preadv64(libc::c_int, *const libc::iovec, libc::c_int, off64_t) -> isize); + + match preadv64.get() { + Some(preadv) => { + let ret = cvt(unsafe { + preadv( + self.as_raw_fd(), + bufs.as_mut_ptr() as *mut libc::iovec as *const libc::iovec, + cmp::min(bufs.len(), max_iov()) as libc::c_int, + offset as _, + ) + })?; + Ok(ret as usize) + } + None => io::default_read_vectored(|b| self.read_at(b, offset), bufs), + } + } + pub fn write(&self, buf: &[u8]) -> io::Result { let ret = cvt(unsafe { libc::write( @@ -178,7 +267,7 @@ pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result { #[cfg(any(target_os = "espidf", target_os = "horizon"))] pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result { - return crate::io::default_write_vectored(|b| self.write(b), bufs); + io::default_write_vectored(|b| self.write(b), bufs) } #[inline] @@ -203,6 +292,95 @@ pub fn write_at(&self, buf: &[u8], offset: u64) -> io::Result { } } + #[cfg(any( + target_os = "emscripten", + target_os = "freebsd", + target_os = "fuchsia", + target_os = "illumos", + target_os = "linux", + target_os = "netbsd", + ))] + pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result { + let ret = cvt(unsafe { + libc::pwritev( + self.as_raw_fd(), + bufs.as_ptr() as *const libc::iovec, + cmp::min(bufs.len(), max_iov()) as libc::c_int, + offset as _, + ) + })?; + Ok(ret as usize) + } + + #[cfg(not(any( + target_os = "android", + target_os = "emscripten", + target_os = "freebsd", + target_os = "fuchsia", + target_os = "illumos", + target_os = "ios", + target_os = "linux", + target_os = "macos", + target_os = "netbsd", + )))] + pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result { + io::default_write_vectored(|b| self.write_at(b, offset), bufs) + } + + // We support some old Android versions that do not have `pwritev` in libc, + // so we use weak linkage and fallback to a direct syscall if not available. + // + // On 32-bit targets, we don't want to deal with weird ABI issues around + // passing 64-bits parameters to syscalls, so we fallback to the default + // implementation if `pwritev` is not available. + #[cfg(all(target_os = "android", target_pointer_width = "64"))] + pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result { + super::weak::syscall! { + fn pwritev( + fd: libc::c_int, + iovec: *const libc::iovec, + n_iovec: libc::c_int, + offset: off64_t + ) -> isize + } + + let ret = cvt(unsafe { + pwritev( + self.as_raw_fd(), + bufs.as_ptr() as *const libc::iovec, + cmp::min(bufs.len(), max_iov()) as libc::c_int, + offset as _, + ) + })?; + Ok(ret as usize) + } + + // We support old MacOS and iOS versions that do not have `pwritev`. There is + // no `syscall` possible in these platform. + #[cfg(any( + all(target_os = "android", target_pointer_width = "32"), + target_os = "ios", + target_os = "macos", + ))] + pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result { + super::weak::weak!(fn pwritev64(libc::c_int, *const libc::iovec, libc::c_int, off64_t) -> isize); + + match pwritev64.get() { + Some(pwritev) => { + let ret = cvt(unsafe { + pwritev( + self.as_raw_fd(), + bufs.as_ptr() as *const libc::iovec, + cmp::min(bufs.len(), max_iov()) as libc::c_int, + offset as _, + ) + })?; + Ok(ret as usize) + } + None => io::default_write_vectored(|b| self.write_at(b, offset), bufs), + } + } + #[cfg(not(any( target_env = "newlib", target_os = "solaris", diff --git a/library/std/src/sys/unix/fs.rs b/library/std/src/sys/unix/fs.rs index bdccb784674..7566fafda24 100644 --- a/library/std/src/sys/unix/fs.rs +++ b/library/std/src/sys/unix/fs.rs @@ -1132,6 +1132,10 @@ pub fn read_buf(&self, cursor: BorrowedCursor<'_>) -> io::Result<()> { self.0.read_buf(cursor) } + pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result { + self.0.read_vectored_at(bufs, offset) + } + pub fn write(&self, buf: &[u8]) -> io::Result { self.0.write(buf) } @@ -1149,6 +1153,10 @@ pub fn write_at(&self, buf: &[u8], offset: u64) -> io::Result { self.0.write_at(buf, offset) } + pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result { + self.0.write_vectored_at(bufs, offset) + } + pub fn flush(&self) -> io::Result<()> { Ok(()) }