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Diffstat (limited to '')
-rw-r--r-- | vendor/rustix/src/imp/linux_raw/conv.rs | 770 |
1 files changed, 770 insertions, 0 deletions
diff --git a/vendor/rustix/src/imp/linux_raw/conv.rs b/vendor/rustix/src/imp/linux_raw/conv.rs new file mode 100644 index 000000000..c80ad58cc --- /dev/null +++ b/vendor/rustix/src/imp/linux_raw/conv.rs @@ -0,0 +1,770 @@ +//! Convert values to [`ArgReg`] and from [`RetReg`]. +//! +//! System call arguments and return values are all communicated with inline +//! asm and FFI as `*mut Opaque`. To protect these raw pointers from escaping +//! or being accidentally misused as they travel through the code, we wrap +//! them in [`ArgReg`] and [`RetReg`] structs. This file provides `From` +//! implementations and explicit conversion functions for converting values +//! into and out of these wrapper structs. +//! +//! # Safety +//! +//! Some of this code is `unsafe` in order to work with raw file descriptors, +//! and some is `unsafe` to interpret the values in a `RetReg`. +#![allow(unsafe_code)] + +use super::c; +use super::fd::{AsRawFd, BorrowedFd, FromRawFd, RawFd}; +#[cfg(not(debug_assertions))] +use super::io::errno::decode_usize_infallible; +#[cfg(feature = "runtime")] +use super::io::errno::try_decode_error; +#[cfg(target_pointer_width = "64")] +use super::io::errno::try_decode_u64; +use super::io::errno::{ + try_decode_c_int, try_decode_c_uint, try_decode_raw_fd, try_decode_usize, try_decode_void, + try_decode_void_star, +}; +use super::reg::{raw_arg, ArgNumber, ArgReg, RetReg, R0}; +#[cfg(any(feature = "thread", feature = "time", target_arch = "x86"))] +use super::time::types::ClockId; +#[cfg(feature = "time")] +use super::time::types::TimerfdClockId; +use crate::ffi::CStr; +use crate::fs::{FileType, Mode, OFlags}; +use crate::io::{self, OwnedFd}; +use crate::process::{Pid, Resource, Signal}; +use crate::utils::{as_mut_ptr, as_ptr}; +use core::mem::MaybeUninit; +use core::ptr::null_mut; +#[cfg(any(feature = "thread", feature = "time", target_arch = "x86"))] +use linux_raw_sys::general::__kernel_clockid_t; +#[cfg(target_pointer_width = "64")] +use linux_raw_sys::general::__kernel_loff_t; +#[cfg(feature = "net")] +use linux_raw_sys::general::socklen_t; +#[cfg(target_pointer_width = "32")] +use linux_raw_sys::general::O_LARGEFILE; + +/// Convert `SYS_*` constants for socketcall. +#[cfg(target_arch = "x86")] +#[inline] +pub(super) fn x86_sys<'a, Num: ArgNumber>(sys: u32) -> ArgReg<'a, Num> { + pass_usize(sys as usize) +} + +/// Pass the "low" half of the endian-specific memory encoding of a `u64`, for +/// 32-bit architectures. +#[cfg(target_pointer_width = "32")] +#[inline] +pub(super) fn lo<'a, Num: ArgNumber>(x: u64) -> ArgReg<'a, Num> { + #[cfg(target_endian = "little")] + let x = x >> 32; + #[cfg(target_endian = "big")] + let x = x & 0xffff_ffff; + + pass_usize(x as usize) +} + +/// Pass the "high" half of the endian-specific memory encoding of a `u64`, for +/// 32-bit architectures. +#[cfg(target_pointer_width = "32")] +#[inline] +pub(super) fn hi<'a, Num: ArgNumber>(x: u64) -> ArgReg<'a, Num> { + #[cfg(target_endian = "little")] + let x = x & 0xffff_ffff; + #[cfg(target_endian = "big")] + let x = x >> 32; + + pass_usize(x as usize) +} + +/// Pass a zero, or null, argument. +#[inline] +pub(super) fn zero<'a, Num: ArgNumber>() -> ArgReg<'a, Num> { + raw_arg(null_mut()) +} + +/// Pass the `mem::size_of` of a type. +#[inline] +pub(super) fn size_of<'a, T: Sized, Num: ArgNumber>() -> ArgReg<'a, Num> { + pass_usize(core::mem::size_of::<T>()) +} + +/// Pass an arbitrary `usize` value. +/// +/// For passing pointers, use `void_star` or other functions which take a raw +/// pointer instead of casting to `usize`, so that provenance is preserved. +#[inline] +pub(super) fn pass_usize<'a, Num: ArgNumber>(t: usize) -> ArgReg<'a, Num> { + raw_arg(t as *mut _) +} + +impl<'a, Num: ArgNumber, T> From<*mut T> for ArgReg<'a, Num> { + #[inline] + fn from(c: *mut T) -> ArgReg<'a, Num> { + raw_arg(c.cast()) + } +} + +impl<'a, Num: ArgNumber, T> From<*const T> for ArgReg<'a, Num> { + #[inline] + fn from(c: *const T) -> ArgReg<'a, Num> { + let mut_ptr = c as *mut T; + raw_arg(mut_ptr.cast()) + } +} + +impl<'a, Num: ArgNumber> From<&'a CStr> for ArgReg<'a, Num> { + #[inline] + fn from(c: &'a CStr) -> Self { + let mut_ptr = c.as_ptr() as *mut u8; + raw_arg(mut_ptr.cast()) + } +} + +impl<'a, Num: ArgNumber> From<Option<&'a CStr>> for ArgReg<'a, Num> { + #[inline] + fn from(t: Option<&'a CStr>) -> Self { + raw_arg(match t { + Some(s) => { + let mut_ptr = s.as_ptr() as *mut u8; + mut_ptr.cast() + } + None => null_mut(), + }) + } +} + +/// Pass a borrowed file-descriptor argument. +impl<'a, Num: ArgNumber> From<BorrowedFd<'a>> for ArgReg<'a, Num> { + #[inline] + fn from(fd: BorrowedFd<'a>) -> Self { + // Safety: `BorrowedFd` ensures that the file descriptor is valid, and the + // lifetime parameter on the resulting `ArgReg` ensures that the result is + // bounded by the `BorrowedFd`'s lifetime. + unsafe { raw_fd(fd.as_raw_fd()) } + } +} + +/// Pass a raw file-descriptor argument. Most users should use [`ArgReg::from`] +/// instead, to preserve I/O safety as long as possible. +/// +/// # Safety +/// +/// `fd` must be a valid open file descriptor. +#[inline] +pub(super) unsafe fn raw_fd<'a, Num: ArgNumber>(fd: RawFd) -> ArgReg<'a, Num> { + // Use `no_fd` when passing `-1` is intended. + debug_assert!(fd == crate::fs::cwd().as_raw_fd() || fd >= 0); + + // Don't pass the `io_uring_register_files_skip` sentry value this way. + #[cfg(feature = "io_uring")] + debug_assert_ne!( + fd, + crate::io_uring::io_uring_register_files_skip().as_raw_fd() + ); + + // Linux doesn't look at the high bits beyond the `c_int`, so use + // zero-extension rather than sign-extension because it's a smaller + // instruction. + let fd: c::c_int = fd; + pass_usize(fd as c::c_uint as usize) +} + +/// Deliberately pass `-1` to a file-descriptor argument, for system calls +/// like `mmap` where this indicates the argument is omitted. +#[inline] +pub(super) fn no_fd<'a, Num: ArgNumber>() -> ArgReg<'a, Num> { + pass_usize(!0_usize) +} + +#[inline] +pub(super) fn slice_just_addr<T: Sized, Num: ArgNumber>(v: &[T]) -> ArgReg<Num> { + let mut_ptr = v.as_ptr() as *mut T; + raw_arg(mut_ptr.cast()) +} + +#[inline] +pub(super) fn slice<T: Sized, Num0: ArgNumber, Num1: ArgNumber>( + v: &[T], +) -> (ArgReg<Num0>, ArgReg<Num1>) { + (slice_just_addr(v), pass_usize(v.len())) +} + +#[inline] +pub(super) fn slice_mut<T: Sized, Num0: ArgNumber, Num1: ArgNumber>( + v: &mut [T], +) -> (ArgReg<Num0>, ArgReg<Num1>) { + (raw_arg(v.as_mut_ptr().cast()), pass_usize(v.len())) +} + +#[inline] +pub(super) fn by_ref<T: Sized, Num: ArgNumber>(t: &T) -> ArgReg<Num> { + let mut_ptr = as_ptr(t) as *mut T; + raw_arg(mut_ptr.cast()) +} + +#[inline] +pub(super) fn by_mut<T: Sized, Num: ArgNumber>(t: &mut T) -> ArgReg<Num> { + raw_arg(as_mut_ptr(t).cast()) +} + +/// Convert an optional mutable reference into a `usize` for passing to a +/// syscall. +#[inline] +pub(super) fn opt_mut<T: Sized, Num: ArgNumber>(t: Option<&mut T>) -> ArgReg<Num> { + // This optimizes into the equivalent of `transmute(t)`, and has the + // advantage of not requiring `unsafe`. + match t { + Some(t) => by_mut(t), + None => raw_arg(null_mut()), + } +} + +/// Convert an optional immutable reference into a `usize` for passing to a +/// syscall. +#[cfg(any(target_arch = "aarch64", target_arch = "riscv64"))] +#[inline] +pub(super) fn opt_ref<'a, T: Sized, Num: ArgNumber>(t: Option<&'a T>) -> ArgReg<'a, Num> { + // This optimizes into the equivalent of `transmute(t)`, and has the + // advantage of not requiring `unsafe`. + match t { + Some(t) => by_ref(t), + None => raw_arg(null_mut()), + } +} + +/// Convert a `c_int` into an `ArgReg`. +/// +/// Be sure to use `raw_fd` to pass `RawFd` values. +#[inline] +pub(super) fn c_int<'a, Num: ArgNumber>(i: c::c_int) -> ArgReg<'a, Num> { + pass_usize(i as usize) +} + +/// Convert a `c_uint` into an `ArgReg`. +#[inline] +pub(super) fn c_uint<'a, Num: ArgNumber>(i: c::c_uint) -> ArgReg<'a, Num> { + pass_usize(i as usize) +} + +#[cfg(target_pointer_width = "64")] +#[inline] +pub(super) fn loff_t<'a, Num: ArgNumber>(i: __kernel_loff_t) -> ArgReg<'a, Num> { + pass_usize(i as usize) +} + +#[cfg(target_pointer_width = "64")] +#[inline] +pub(super) fn loff_t_from_u64<'a, Num: ArgNumber>(i: u64) -> ArgReg<'a, Num> { + // `loff_t` is signed, but syscalls which expect `loff_t` return `EINVAL` + // if it's outside the signed `i64` range, so we can silently cast. + pass_usize(i as usize) +} + +#[cfg(any(feature = "thread", feature = "time", target_arch = "x86"))] +impl<'a, Num: ArgNumber> From<ClockId> for ArgReg<'a, Num> { + #[inline] + fn from(i: ClockId) -> Self { + pass_usize(i as __kernel_clockid_t as usize) + } +} + +#[cfg(feature = "time")] +impl<'a, Num: ArgNumber> From<TimerfdClockId> for ArgReg<'a, Num> { + #[inline] + fn from(i: TimerfdClockId) -> Self { + pass_usize(i as __kernel_clockid_t as usize) + } +} + +#[cfg(feature = "net")] +#[inline] +pub(super) fn socklen_t<'a, Num: ArgNumber>(i: socklen_t) -> ArgReg<'a, Num> { + pass_usize(i as usize) +} + +impl<'a, Num: ArgNumber> From<Mode> for ArgReg<'a, Num> { + #[inline] + fn from(mode: Mode) -> Self { + pass_usize(mode.bits() as usize) + } +} + +impl<'a, Num: ArgNumber> From<(Mode, FileType)> for ArgReg<'a, Num> { + #[inline] + fn from(pair: (Mode, FileType)) -> Self { + pass_usize(pair.0.as_raw_mode() as usize | pair.1.as_raw_mode() as usize) + } +} + +impl<'a, Num: ArgNumber> From<crate::fs::AtFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::fs::AtFlags) -> Self { + c_uint(flags.bits()) + } +} + +impl<'a, Num: ArgNumber> From<crate::fs::MemfdFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::fs::MemfdFlags) -> Self { + c_uint(flags.bits()) + } +} + +impl<'a, Num: ArgNumber> From<crate::fs::RenameFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::fs::RenameFlags) -> Self { + c_uint(flags.bits()) + } +} + +impl<'a, Num: ArgNumber> From<crate::fs::StatxFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::fs::StatxFlags) -> Self { + c_uint(flags.bits()) + } +} + +impl<'a, Num: ArgNumber> From<crate::fs::FdFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::fs::FdFlags) -> Self { + c_uint(flags.bits()) + } +} + +impl<'a, Num: ArgNumber> From<crate::io::PipeFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::io::PipeFlags) -> Self { + c_uint(flags.bits()) + } +} + +impl<'a, Num: ArgNumber> From<crate::io::DupFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::io::DupFlags) -> Self { + c_uint(flags.bits()) + } +} + +impl<'a, Num: ArgNumber> From<crate::io::ReadWriteFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::io::ReadWriteFlags) -> Self { + c_uint(flags.bits()) + } +} + +impl<'a, Num: ArgNumber> From<crate::io::EventfdFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::io::EventfdFlags) -> Self { + c_uint(flags.bits()) + } +} + +impl<'a, Num: ArgNumber> From<crate::io::epoll::CreateFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::io::epoll::CreateFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(any(feature = "mm", feature = "time", target_arch = "x86"))] // vdso.rs uses `madvise` +impl<'a, Num: ArgNumber> From<crate::imp::mm::types::ProtFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::imp::mm::types::ProtFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(any(feature = "mm", feature = "time", target_arch = "x86"))] // vdso.rs uses `madvise` +impl<'a, Num: ArgNumber> From<crate::imp::mm::types::MsyncFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::imp::mm::types::MsyncFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(any(feature = "mm", feature = "time", target_arch = "x86"))] // vdso.rs uses `madvise` +impl<'a, Num: ArgNumber> From<crate::imp::mm::types::MremapFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::imp::mm::types::MremapFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(any(feature = "mm", feature = "time", target_arch = "x86"))] // vdso.rs uses `madvise` +impl<'a, Num: ArgNumber> From<crate::imp::mm::types::MlockFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::imp::mm::types::MlockFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(any(feature = "mm", feature = "time", target_arch = "x86"))] // vdso.rs uses `madvise` +impl<'a, Num: ArgNumber> From<crate::imp::mm::types::MapFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::imp::mm::types::MapFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(any(feature = "mm", feature = "time", target_arch = "x86"))] // vdso.rs uses `madvise` +impl<'a, Num: ArgNumber> From<crate::imp::mm::types::MprotectFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::imp::mm::types::MprotectFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(any(feature = "mm", feature = "time", target_arch = "x86"))] // vdso.rs uses `madvise` +impl<'a, Num: ArgNumber> From<crate::imp::mm::types::UserfaultfdFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::imp::mm::types::UserfaultfdFlags) -> Self { + c_uint(flags.bits()) + } +} + +impl<'a, Num: ArgNumber> From<crate::imp::process::types::MembarrierCommand> for ArgReg<'a, Num> { + #[inline] + fn from(cmd: crate::imp::process::types::MembarrierCommand) -> Self { + c_uint(cmd as u32) + } +} + +impl<'a, Num: ArgNumber> From<crate::process::Cpuid> for ArgReg<'a, Num> { + #[inline] + fn from(cpuid: crate::process::Cpuid) -> Self { + c_uint(cpuid.as_raw()) + } +} + +#[cfg(target_pointer_width = "64")] +#[inline] +pub(super) fn dev_t<'a, Num: ArgNumber>(dev: u64) -> ArgReg<'a, Num> { + pass_usize(dev as usize) +} + +#[cfg(target_pointer_width = "32")] +#[inline] +pub(super) fn dev_t<'a, Num: ArgNumber>(dev: u64) -> io::Result<ArgReg<'a, Num>> { + use core::convert::TryInto; + Ok(pass_usize(dev.try_into().map_err(|_err| io::Errno::INVAL)?)) +} + +#[cfg(target_pointer_width = "32")] +#[inline] +fn oflags_bits(oflags: OFlags) -> c::c_uint { + let mut bits = oflags.bits(); + // Add `O_LARGEFILE`, unless `O_PATH` is set, as Linux returns `EINVAL` + // when both are set. + if !oflags.contains(OFlags::PATH) { + bits |= O_LARGEFILE; + } + bits +} + +#[cfg(target_pointer_width = "64")] +#[inline] +const fn oflags_bits(oflags: OFlags) -> c::c_uint { + oflags.bits() +} + +impl<'a, Num: ArgNumber> From<OFlags> for ArgReg<'a, Num> { + #[inline] + fn from(oflags: OFlags) -> Self { + pass_usize(oflags_bits(oflags) as usize) + } +} + +/// Convert an `OFlags` into a `u64` for use in the `open_how` struct. +#[inline] +pub(super) fn oflags_for_open_how(oflags: OFlags) -> u64 { + u64::from(oflags_bits(oflags)) +} + +impl<'a, Num: ArgNumber> From<crate::fs::FallocateFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::fs::FallocateFlags) -> Self { + c_uint(flags.bits()) + } +} + +/// Convert a `Resource` into a syscall argument. +impl<'a, Num: ArgNumber> From<Resource> for ArgReg<'a, Num> { + #[inline] + fn from(resource: Resource) -> Self { + c_uint(resource as c::c_uint) + } +} + +impl<'a, Num: ArgNumber> From<Pid> for ArgReg<'a, Num> { + #[inline] + fn from(pid: Pid) -> Self { + pass_usize(pid.as_raw_nonzero().get() as usize) + } +} + +#[inline] +pub(super) fn negative_pid<'a, Num: ArgNumber>(pid: Pid) -> ArgReg<'a, Num> { + pass_usize(pid.as_raw_nonzero().get().wrapping_neg() as usize) +} + +impl<'a, Num: ArgNumber> From<Signal> for ArgReg<'a, Num> { + #[inline] + fn from(sig: Signal) -> Self { + pass_usize(sig as usize) + } +} + +impl<'a, Num: ArgNumber> From<crate::fs::Advice> for ArgReg<'a, Num> { + #[inline] + fn from(advice: crate::fs::Advice) -> Self { + c_uint(advice as c::c_uint) + } +} + +impl<'a, Num: ArgNumber> From<crate::fs::SealFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::fs::SealFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(feature = "io_uring")] +impl<'a, Num: ArgNumber> From<crate::io_uring::IoringEnterFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::io_uring::IoringEnterFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(feature = "time")] +impl<'a, Num: ArgNumber> From<crate::time::TimerfdFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::time::TimerfdFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(feature = "time")] +impl<'a, Num: ArgNumber> From<crate::time::TimerfdTimerFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::time::TimerfdTimerFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(feature = "rand")] +impl<'a, Num: ArgNumber> From<crate::rand::GetRandomFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::rand::GetRandomFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(feature = "net")] +impl<'a, Num: ArgNumber> From<crate::net::RecvFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::net::RecvFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(feature = "net")] +impl<'a, Num: ArgNumber> From<crate::net::SendFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::net::SendFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(feature = "net")] +impl<'a, Num: ArgNumber> From<crate::net::AcceptFlags> for ArgReg<'a, Num> { + #[inline] + fn from(flags: crate::net::AcceptFlags) -> Self { + c_uint(flags.bits()) + } +} + +#[cfg(feature = "net")] +impl<'a, Num: ArgNumber> From<crate::net::AddressFamily> for ArgReg<'a, Num> { + #[inline] + fn from(family: crate::net::AddressFamily) -> Self { + c_uint(family.0.into()) + } +} + +#[cfg(feature = "net")] +impl<'a, Num: ArgNumber> From<(crate::net::SocketType, crate::net::SocketFlags)> + for ArgReg<'a, Num> +{ + #[inline] + fn from(pair: (crate::net::SocketType, crate::net::SocketFlags)) -> Self { + c_uint(pair.0 .0 | pair.1.bits()) + } +} + +#[cfg(feature = "thread")] +impl<'a, Num: ArgNumber> From<(crate::thread::FutexOperation, crate::thread::FutexFlags)> + for ArgReg<'a, Num> +{ + #[inline] + fn from(pair: (crate::thread::FutexOperation, crate::thread::FutexFlags)) -> Self { + c_uint(pair.0 as u32 | pair.1.bits()) + } +} + +impl<'a, Num: ArgNumber> From<crate::fs::Access> for ArgReg<'a, Num> { + #[inline] + fn from(access: crate::fs::Access) -> Self { + c_uint(access.bits()) + } +} + +#[cfg(feature = "net")] +impl<'a, Num: ArgNumber> From<crate::net::SocketType> for ArgReg<'a, Num> { + #[inline] + fn from(type_: crate::net::SocketType) -> Self { + c_uint(type_.0) + } +} + +#[cfg(feature = "net")] +impl<'a, Num: ArgNumber> From<crate::net::Protocol> for ArgReg<'a, Num> { + #[inline] + fn from(protocol: crate::net::Protocol) -> Self { + c_uint(protocol.0) + } +} + +impl<'a, Num: ArgNumber, T> From<&'a mut MaybeUninit<T>> for ArgReg<'a, Num> { + #[inline] + fn from(t: &'a mut MaybeUninit<T>) -> Self { + raw_arg(t.as_mut_ptr().cast()) + } +} + +/// Convert a `usize` returned from a syscall that effectively returns `()` on +/// success. +/// +/// # Safety +/// +/// The caller must ensure that this is the return value of a syscall which +/// just returns 0 on success. +#[inline] +pub(super) unsafe fn ret(raw: RetReg<R0>) -> io::Result<()> { + try_decode_void(raw) +} + +/// Convert a `usize` returned from a syscall that doesn't return on success. +/// +/// # Safety +/// +/// The caller must ensure that this is the return value of a syscall which +/// doesn't return on success. +#[cfg(feature = "runtime")] +#[inline] +pub(super) unsafe fn ret_error(raw: RetReg<R0>) -> io::Errno { + try_decode_error(raw) +} + +/// Convert a `usize` returned from a syscall that effectively always returns +/// `()`. +/// +/// # Safety +/// +/// The caller must ensure that this is the return value of a syscall which +/// always returns `()`. +#[inline] +pub(super) unsafe fn ret_infallible(raw: RetReg<R0>) { + #[cfg(debug_assertions)] + { + try_decode_void(raw).unwrap() + } + #[cfg(not(debug_assertions))] + drop(raw); +} + +/// Convert a `usize` returned from a syscall that effectively returns a +/// `c_int` on success. +#[inline] +pub(super) fn ret_c_int(raw: RetReg<R0>) -> io::Result<c::c_int> { + try_decode_c_int(raw) +} + +/// Convert a `usize` returned from a syscall that effectively returns a +/// `c_uint` on success. +#[inline] +pub(super) fn ret_c_uint(raw: RetReg<R0>) -> io::Result<c::c_uint> { + try_decode_c_uint(raw) +} + +/// Convert a `usize` returned from a syscall that effectively returns a `u64` +/// on success. +#[cfg(target_pointer_width = "64")] +#[inline] +pub(super) fn ret_u64(raw: RetReg<R0>) -> io::Result<u64> { + try_decode_u64(raw) +} + +/// Convert a `usize` returned from a syscall that effectively returns a +/// `usize` on success. +#[inline] +pub(super) fn ret_usize(raw: RetReg<R0>) -> io::Result<usize> { + try_decode_usize(raw) +} + +/// Convert a `usize` returned from a syscall that effectively always +/// returns a `usize`. +/// +/// # Safety +/// +/// This function must only be used with return values from infallible +/// syscalls. +#[inline] +pub(super) unsafe fn ret_usize_infallible(raw: RetReg<R0>) -> usize { + #[cfg(debug_assertions)] + { + try_decode_usize(raw).unwrap() + } + #[cfg(not(debug_assertions))] + { + decode_usize_infallible(raw) + } +} + +/// Convert a `usize` returned from a syscall that effectively returns an +/// `OwnedFd` on success. +/// +/// # Safety +/// +/// The caller must ensure that this is the return value of a syscall which +/// returns an owned file descriptor. +#[inline] +pub(super) unsafe fn ret_owned_fd(raw: RetReg<R0>) -> io::Result<OwnedFd> { + let raw_fd = try_decode_raw_fd(raw)?; + Ok(OwnedFd::from(crate::imp::fd::OwnedFd::from_raw_fd(raw_fd))) +} + +/// Convert the return value of `dup2` and `dup3`. +/// +/// When these functions succeed, they return the same value as their second +/// argument, so we don't construct a new `OwnedFd`. +/// +/// # Safety +/// +/// The caller must ensure that this is the return value of a syscall which +/// returns a file descriptor. +#[inline] +pub(super) unsafe fn ret_discarded_fd(raw: RetReg<R0>) -> io::Result<()> { + let _raw_fd = try_decode_raw_fd(raw)?; + Ok(()) +} + +/// Convert a `usize` returned from a syscall that effectively returns a +/// `*mut c_void` on success. +#[inline] +pub(super) fn ret_void_star(raw: RetReg<R0>) -> io::Result<*mut c::c_void> { + try_decode_void_star(raw) +} |