Jeremy Soller
112 lines
2.6 KiB
Rust
112 lines
2.6 KiB
Rust
//! sys/uio implementation for Redox, following http://pubs.opengroup.org/onlinepubs/007904875/basedefs/sys/uio.h.html
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use alloc::vec::Vec;
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use core::slice;
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use crate::{
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header::{errno, unistd},
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platform::{self, types::*},
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};
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pub const IOV_MAX: c_int = 1024;
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#[repr(C)]
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#[derive(Debug)]
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pub struct iovec {
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pub iov_base: *mut c_void,
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pub iov_len: size_t,
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}
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impl iovec {
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unsafe fn to_slice(&self) -> &mut [u8] {
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slice::from_raw_parts_mut(self.iov_base as *mut u8, self.iov_len as usize)
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}
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}
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unsafe fn gather(iovs: &[iovec]) -> Vec<u8> {
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let mut vec = Vec::new();
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for iov in iovs.iter() {
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vec.extend_from_slice(iov.to_slice());
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}
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vec
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}
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unsafe fn scatter(iovs: &[iovec], vec: Vec<u8>) {
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let mut i = 0;
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for iov in iovs.iter() {
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let slice = iov.to_slice();
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slice.copy_from_slice(&vec[i..][..slice.len()]);
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i += slice.len();
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}
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}
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#[unsafe(no_mangle)]
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pub unsafe extern "C" fn preadv(
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fd: c_int,
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iov: *const iovec,
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iovcnt: c_int,
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offset: off_t,
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) -> ssize_t {
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if iovcnt < 0 || iovcnt > IOV_MAX {
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platform::ERRNO.set(errno::EINVAL);
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return -1;
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}
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let iovs = slice::from_raw_parts(iov, iovcnt as usize);
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let mut vec = gather(iovs);
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let ret = unistd::pread(fd, vec.as_mut_ptr() as *mut c_void, vec.len(), offset);
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scatter(iovs, vec);
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ret
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}
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#[unsafe(no_mangle)]
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pub unsafe extern "C" fn pwritev(
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fd: c_int,
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iov: *const iovec,
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iovcnt: c_int,
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offset: off_t,
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) -> ssize_t {
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if iovcnt < 0 || iovcnt > IOV_MAX {
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platform::ERRNO.set(errno::EINVAL);
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return -1;
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}
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let iovs = slice::from_raw_parts(iov, iovcnt as usize);
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let vec = gather(iovs);
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unistd::pwrite(fd, vec.as_ptr() as *const c_void, vec.len(), offset)
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}
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#[unsafe(no_mangle)]
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pub unsafe extern "C" fn readv(fd: c_int, iov: *const iovec, iovcnt: c_int) -> ssize_t {
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if iovcnt < 0 || iovcnt > IOV_MAX {
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platform::ERRNO.set(errno::EINVAL);
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return -1;
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}
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let iovs = slice::from_raw_parts(iov, iovcnt as usize);
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let mut vec = gather(iovs);
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let ret = unistd::read(fd, vec.as_mut_ptr() as *mut c_void, vec.len());
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scatter(iovs, vec);
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ret
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}
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#[unsafe(no_mangle)]
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pub unsafe extern "C" fn writev(fd: c_int, iov: *const iovec, iovcnt: c_int) -> ssize_t {
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if iovcnt < 0 || iovcnt > IOV_MAX {
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platform::ERRNO.set(errno::EINVAL);
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return -1;
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}
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let iovs = slice::from_raw_parts(iov, iovcnt as usize);
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let vec = gather(iovs);
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unistd::write(fd, vec.as_ptr() as *const c_void, vec.len())
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}
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