auronandace
61 lines
1.9 KiB
Rust
61 lines
1.9 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 core::slice;
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use crate::{
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header::{errno, limits::IOV_MAX, unistd},
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platform::{
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self,
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types::{c_int, c_void, ssize_t},
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},
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};
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pub use crate::header::bits_iovec::{gather, iovec, scatter};
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/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/readv.html>.
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///
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/// Equivalent to `read()` but places the input data into the `iovcnt` buffers
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/// specified by the members of the `iov` array.
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///
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/// When successful, returns a non-negative number indicating the number of
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/// bytes actually read. Upon failure, returns `-1`.
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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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///
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/// Equivalent to `write()` but shall gather output data from the `iovcnt`
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/// buffers specified by the members of the `iov` array.
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///
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/// When successful, returns a non-negative number indicating the number of
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/// bytes actually written to the file associated with `fildes`. Upon failure,
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/// returns `-1`.
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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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