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//! libc syscalls supporting `rustix::mm`.
use super::super::c;
#[cfg(any(target_os = "android", target_os = "linux"))]
use super::super::conv::syscall_ret_owned_fd;
use super::super::conv::{borrowed_fd, no_fd, ret};
use super::super::offset::libc_mmap;
#[cfg(not(target_os = "redox"))]
use super::types::Advice;
#[cfg(target_os = "linux")]
use super::types::MremapFlags;
use super::types::{MapFlags, MprotectFlags, MsyncFlags, ProtFlags};
#[cfg(any(target_os = "android", target_os = "linux"))]
use super::types::{MlockFlags, UserfaultfdFlags};
use crate::fd::BorrowedFd;
use crate::io;
#[cfg(any(target_os = "android", target_os = "linux"))]
use crate::io::OwnedFd;
#[cfg(not(target_os = "redox"))]
pub(crate) fn madvise(addr: *mut c::c_void, len: usize, advice: Advice) -> io::Result<()> {
// On Linux platforms, `MADV_DONTNEED` has the same value as
// `POSIX_MADV_DONTNEED` but different behavior. We remap it to a different
// value, and check for it here.
#[cfg(target_os = "linux")]
if let Advice::LinuxDontNeed = advice {
return unsafe { ret(c::madvise(addr, len, c::MADV_DONTNEED)) };
}
#[cfg(not(target_os = "android"))]
{
let err = unsafe { c::posix_madvise(addr, len, advice as c::c_int) };
// `posix_madvise` returns its error status rather than using `errno`.
if err == 0 {
Ok(())
} else {
Err(io::Errno(err))
}
}
#[cfg(target_os = "android")]
{
if let Advice::DontNeed = advice {
// Do nothing. Linux's `MADV_DONTNEED` isn't the same as
// `POSIX_MADV_DONTNEED`, so just discard `MADV_DONTNEED`.
Ok(())
} else {
unsafe { ret(c::madvise(addr, len, advice as c::c_int)) }
}
}
}
pub(crate) unsafe fn msync(addr: *mut c::c_void, len: usize, flags: MsyncFlags) -> io::Result<()> {
let err = c::msync(addr, len, flags.bits());
// `msync` returns its error status rather than using `errno`.
if err == 0 {
Ok(())
} else {
Err(io::Errno(err))
}
}
/// # Safety
///
/// `mmap` is primarily unsafe due to the `addr` parameter, as anything working
/// with memory pointed to by raw pointers is unsafe.
pub(crate) unsafe fn mmap(
ptr: *mut c::c_void,
len: usize,
prot: ProtFlags,
flags: MapFlags,
fd: BorrowedFd<'_>,
offset: u64,
) -> io::Result<*mut c::c_void> {
let res = libc_mmap(
ptr,
len,
prot.bits(),
flags.bits(),
borrowed_fd(fd),
offset as i64,
);
if res == c::MAP_FAILED {
Err(io::Errno::last_os_error())
} else {
Ok(res)
}
}
/// # Safety
///
/// `mmap` is primarily unsafe due to the `addr` parameter, as anything working
/// with memory pointed to by raw pointers is unsafe.
pub(crate) unsafe fn mmap_anonymous(
ptr: *mut c::c_void,
len: usize,
prot: ProtFlags,
flags: MapFlags,
) -> io::Result<*mut c::c_void> {
let res = libc_mmap(
ptr,
len,
prot.bits(),
flags.bits() | c::MAP_ANONYMOUS,
no_fd(),
0,
);
if res == c::MAP_FAILED {
Err(io::Errno::last_os_error())
} else {
Ok(res)
}
}
pub(crate) unsafe fn mprotect(
ptr: *mut c::c_void,
len: usize,
flags: MprotectFlags,
) -> io::Result<()> {
ret(c::mprotect(ptr, len, flags.bits()))
}
pub(crate) unsafe fn munmap(ptr: *mut c::c_void, len: usize) -> io::Result<()> {
ret(c::munmap(ptr, len))
}
/// # Safety
///
/// `mremap` is primarily unsafe due to the `old_address` parameter, as
/// anything working with memory pointed to by raw pointers is unsafe.
#[cfg(target_os = "linux")]
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> {
let res = c::mremap(old_address, old_size, new_size, flags.bits());
if res == c::MAP_FAILED {
Err(io::Errno::last_os_error())
} else {
Ok(res)
}
}
/// # 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.
#[cfg(target_os = "linux")]
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> {
let res = c::mremap(
old_address,
old_size,
new_size,
flags.bits() | c::MAP_FIXED,
new_address,
);
if res == c::MAP_FAILED {
Err(io::Errno::last_os_error())
} else {
Ok(res)
}
}
/// # 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(c::mlock(addr, length))
}
/// # Safety
///
/// `mlock_with` operates on raw pointers and may round out to the nearest page
/// boundaries.
#[cfg(any(target_os = "android", target_os = "linux"))]
#[inline]
pub(crate) unsafe fn mlock_with(
addr: *mut c::c_void,
length: usize,
flags: MlockFlags,
) -> io::Result<()> {
weak_or_syscall! {
fn mlock2(
addr: *const c::c_void,
len: c::size_t,
flags: c::c_int
) via SYS_mlock2 -> c::c_int
}
ret(mlock2(addr, length, flags.bits()))
}
/// # 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(c::munlock(addr, length))
}
#[cfg(any(target_os = "android", target_os = "linux"))]
pub(crate) unsafe fn userfaultfd(flags: UserfaultfdFlags) -> io::Result<OwnedFd> {
syscall_ret_owned_fd(c::syscall(c::SYS_userfaultfd, flags.bits()))
}
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