auronandace
122 lines
3.2 KiB
Rust
122 lines
3.2 KiB
Rust
//! `sys/uio.h` implementation.
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//!
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//! See <https://pubs.opengroup.org/onlinepubs/9799919799/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::{
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self,
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types::{c_int, c_void, off_t, size_t, ssize_t},
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},
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};
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pub const IOV_MAX: c_int = 1024;
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/// See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/sys_uio.h.html>.
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#[repr(C)]
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#[derive(Debug, CheckVsLibcCrate)]
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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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unsafe { slice::from_raw_parts_mut(self.iov_base.cast::<u8>(), self.iov_len) }
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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(unsafe { 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 = unsafe { 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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/// Non-POSIX, see <https://man7.org/linux/man-pages/man2/readv.2.html>.
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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 !(0..=IOV_MAX).contains(&iovcnt) {
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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 = unsafe { slice::from_raw_parts(iov, iovcnt as usize) };
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let mut vec = unsafe { gather(iovs) };
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let ret = unsafe { unistd::pread(fd, vec.as_mut_ptr().cast::<c_void>(), vec.len(), offset) };
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unsafe { scatter(iovs, vec) };
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ret
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}
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/// Non-POSIX, see <https://man7.org/linux/man-pages/man2/readv.2.html>.
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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 !(0..=IOV_MAX).contains(&iovcnt) {
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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 = unsafe { slice::from_raw_parts(iov, iovcnt as usize) };
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let vec = unsafe { gather(iovs) };
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unsafe { unistd::pwrite(fd, vec.as_ptr().cast::<c_void>(), vec.len(), offset) }
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}
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/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/readv.html>.
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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 !(0..=IOV_MAX).contains(&iovcnt) {
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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 = unsafe { slice::from_raw_parts(iov, iovcnt as usize) };
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let mut vec = unsafe { gather(iovs) };
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let ret = unsafe { unistd::read(fd, vec.as_mut_ptr().cast::<c_void>(), vec.len()) };
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unsafe { scatter(iovs, vec) };
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ret
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}
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/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/writev.html>.
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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 !(0..=IOV_MAX).contains(&iovcnt) {
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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 = unsafe { slice::from_raw_parts(iov, iovcnt as usize) };
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let vec = unsafe { gather(iovs) };
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unsafe { unistd::write(fd, vec.as_ptr().cast::<c_void>(), vec.len()) }
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}
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