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//! linux_raw syscalls supporting `rustix::io`.
//!
//! # Safety
//!
//! See the `rustix::backend` module documentation for details.
#![allow(unsafe_code)]
#![allow(clippy::undocumented_unsafe_blocks)]
use super::types::{
Advice, MapFlags, MlockAllFlags, MlockFlags, MprotectFlags, MremapFlags, MsyncFlags, ProtFlags,
UserfaultfdFlags,
};
use crate::backend::c;
#[cfg(target_pointer_width = "64")]
use crate::backend::conv::loff_t_from_u64;
use crate::backend::conv::{c_uint, no_fd, pass_usize, ret, ret_owned_fd, ret_void_star};
use crate::fd::{BorrowedFd, OwnedFd};
use crate::io;
use linux_raw_sys::general::MAP_ANONYMOUS;
#[inline]
pub(crate) fn madvise(addr: *mut c::c_void, len: usize, advice: Advice) -> io::Result<()> {
unsafe {
ret(syscall!(
__NR_madvise,
addr,
pass_usize(len),
c_uint(advice as c::c_uint)
))
}
}
#[inline]
pub(crate) unsafe fn msync(addr: *mut c::c_void, len: usize, flags: MsyncFlags) -> io::Result<()> {
ret(syscall!(__NR_msync, addr, pass_usize(len), flags))
}
/// # Safety
///
/// `mmap` is primarily unsafe due to the `addr` parameter, as anything working
/// with memory pointed to by raw pointers is unsafe.
#[inline]
pub(crate) unsafe fn mmap(
addr: *mut c::c_void,
length: usize,
prot: ProtFlags,
flags: MapFlags,
fd: BorrowedFd<'_>,
offset: u64,
) -> io::Result<*mut c::c_void> {
#[cfg(target_pointer_width = "32")]
{
ret_void_star(syscall!(
__NR_mmap2,
addr,
pass_usize(length),
prot,
flags,
fd,
(offset / 4096)
.try_into()
.map(pass_usize)
.map_err(|_| io::Errno::INVAL)?
))
}
#[cfg(target_pointer_width = "64")]
{
ret_void_star(syscall!(
__NR_mmap,
addr,
pass_usize(length),
prot,
flags,
fd,
loff_t_from_u64(offset)
))
}
}
/// # Safety
///
/// `mmap` is primarily unsafe due to the `addr` parameter, as anything working
/// with memory pointed to by raw pointers is unsafe.
#[inline]
pub(crate) unsafe fn mmap_anonymous(
addr: *mut c::c_void,
length: usize,
prot: ProtFlags,
flags: MapFlags,
) -> io::Result<*mut c::c_void> {
#[cfg(target_pointer_width = "32")]
{
ret_void_star(syscall!(
__NR_mmap2,
addr,
pass_usize(length),
prot,
c_uint(flags.bits() | MAP_ANONYMOUS),
no_fd(),
pass_usize(0)
))
}
#[cfg(target_pointer_width = "64")]
{
ret_void_star(syscall!(
__NR_mmap,
addr,
pass_usize(length),
prot,
c_uint(flags.bits() | MAP_ANONYMOUS),
no_fd(),
loff_t_from_u64(0)
))
}
}
#[inline]
pub(crate) unsafe fn mprotect(
ptr: *mut c::c_void,
len: usize,
flags: MprotectFlags,
) -> io::Result<()> {
ret(syscall!(__NR_mprotect, ptr, pass_usize(len), flags))
}
/// # Safety
///
/// `munmap` is primarily unsafe due to the `addr` parameter, as anything
/// working with memory pointed to by raw pointers is unsafe.
#[inline]
pub(crate) unsafe fn munmap(addr: *mut c::c_void, length: usize) -> io::Result<()> {
ret(syscall!(__NR_munmap, addr, pass_usize(length)))
}
/// # Safety
///
/// `mremap` is primarily unsafe due to the `old_address` parameter, as
/// anything working with memory pointed to by raw pointers is unsafe.
#[inline]
pub(crate) unsafe fn mremap(
old_address: *mut c::c_void,
old_size: usize,
new_size: usize,
flags: MremapFlags,
) -> io::Result<*mut c::c_void> {
ret_void_star(syscall!(
__NR_mremap,
old_address,
pass_usize(old_size),
pass_usize(new_size),
flags
))
}
/// # Safety
///
/// `mremap_fixed` is primarily unsafe due to the `old_address` and
/// `new_address` parameters, as anything working with memory pointed to by raw
/// pointers is unsafe.
#[inline]
pub(crate) unsafe fn mremap_fixed(
old_address: *mut c::c_void,
old_size: usize,
new_size: usize,
flags: MremapFlags,
new_address: *mut c::c_void,
) -> io::Result<*mut c::c_void> {
ret_void_star(syscall!(
__NR_mremap,
old_address,
pass_usize(old_size),
pass_usize(new_size),
flags,
new_address
))
}
/// # Safety
///
/// `mlock` operates on raw pointers and may round out to the nearest page
/// boundaries.
#[inline]
pub(crate) unsafe fn mlock(addr: *mut c::c_void, length: usize) -> io::Result<()> {
ret(syscall!(__NR_mlock, addr, pass_usize(length)))
}
/// # Safety
///
/// `mlock_with` operates on raw pointers and may round out to the nearest page
/// boundaries.
#[inline]
pub(crate) unsafe fn mlock_with(
addr: *mut c::c_void,
length: usize,
flags: MlockFlags,
) -> io::Result<()> {
ret(syscall!(__NR_mlock2, addr, pass_usize(length), flags))
}
/// # Safety
///
/// `munlock` operates on raw pointers and may round out to the nearest page
/// boundaries.
#[inline]
pub(crate) unsafe fn munlock(addr: *mut c::c_void, length: usize) -> io::Result<()> {
ret(syscall!(__NR_munlock, addr, pass_usize(length)))
}
#[inline]
pub(crate) unsafe fn userfaultfd(flags: UserfaultfdFlags) -> io::Result<OwnedFd> {
ret_owned_fd(syscall_readonly!(__NR_userfaultfd, flags))
}
/// Locks all pages mapped into the address space of the calling process.
///
/// This includes the pages of the code, data, and stack segment, as well as
/// shared libraries, user space kernel data, shared memory, and memory-mapped
/// files. All mapped pages are guaranteed to be resident in RAM when the call
/// returns successfully; the pages are guaranteed to stay in RAM until later
/// unlocked.
#[inline]
pub(crate) fn mlockall(flags: MlockAllFlags) -> io::Result<()> {
// When `mlockall` is used with `MCL_ONFAULT | MCL_FUTURE`, the ordering
// of `mlockall` with respect to arbitrary loads may be significant,
// because if a load happens and evokes a fault before the `mlockall`,
// the memory doesn't get locked, but if the load and therefore
// the fault happens after, then the memory does get locked.
// So to be conservative in this regard, we use `syscall` instead
// of `syscall_readonly`
unsafe { ret(syscall!(__NR_mlockall, flags)) }
}
/// Unlocks all pages mapped into the address space of the calling process.
#[inline]
pub(crate) fn munlockall() -> io::Result<()> {
unsafe { ret(syscall_readonly!(__NR_munlockall)) }
}