diff options
Diffstat (limited to 'vendor/memmap2-0.2.3/src/unix.rs')
| -rw-r--r-- | vendor/memmap2-0.2.3/src/unix.rs | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/vendor/memmap2-0.2.3/src/unix.rs b/vendor/memmap2-0.2.3/src/unix.rs new file mode 100644 index 000000000..2d45e68d6 --- /dev/null +++ b/vendor/memmap2-0.2.3/src/unix.rs @@ -0,0 +1,235 @@ +extern crate libc; + +use std::fs::File; +use std::os::unix::io::{AsRawFd, RawFd}; +use std::{io, ptr}; + +#[cfg(any( + all(target_os = "linux", not(target_arch = "mips")), + target_os = "freebsd", + target_os = "android" +))] +const MAP_STACK: libc::c_int = libc::MAP_STACK; + +#[cfg(not(any( + all(target_os = "linux", not(target_arch = "mips")), + target_os = "freebsd", + target_os = "android" +)))] +const MAP_STACK: libc::c_int = 0; + +#[cfg(any(target_os = "linux", target_os = "android"))] +const MAP_POPULATE: libc::c_int = libc::MAP_POPULATE; + +#[cfg(not(any(target_os = "linux", target_os = "android")))] +const MAP_POPULATE: libc::c_int = 0; + +pub struct MmapInner { + ptr: *mut libc::c_void, + len: usize, +} + +impl MmapInner { + /// Creates a new `MmapInner`. + /// + /// This is a thin wrapper around the `mmap` sytem call. + fn new( + len: usize, + prot: libc::c_int, + flags: libc::c_int, + file: RawFd, + offset: u64, + ) -> io::Result<MmapInner> { + let alignment = offset % page_size() as u64; + let aligned_offset = offset - alignment; + let aligned_len = len + alignment as usize; + if aligned_len == 0 { + // Normally the OS would catch this, but it segfaults under QEMU. + return Err(io::Error::new( + io::ErrorKind::InvalidInput, + "memory map must have a non-zero length", + )); + } + + unsafe { + let ptr = libc::mmap( + ptr::null_mut(), + aligned_len as libc::size_t, + prot, + flags, + file, + aligned_offset as libc::off_t, + ); + + if ptr == libc::MAP_FAILED { + Err(io::Error::last_os_error()) + } else { + Ok(MmapInner { + ptr: ptr.offset(alignment as isize), + len, + }) + } + } + } + + pub fn map(len: usize, file: &File, offset: u64, populate: bool) -> io::Result<MmapInner> { + let populate = if populate { MAP_POPULATE } else { 0 }; + MmapInner::new( + len, + libc::PROT_READ, + libc::MAP_SHARED | populate, + file.as_raw_fd(), + offset, + ) + } + + pub fn map_exec(len: usize, file: &File, offset: u64, populate: bool) -> io::Result<MmapInner> { + let populate = if populate { MAP_POPULATE } else { 0 }; + MmapInner::new( + len, + libc::PROT_READ | libc::PROT_EXEC, + libc::MAP_SHARED | populate, + file.as_raw_fd(), + offset, + ) + } + + pub fn map_mut(len: usize, file: &File, offset: u64, populate: bool) -> io::Result<MmapInner> { + let populate = if populate { MAP_POPULATE } else { 0 }; + MmapInner::new( + len, + libc::PROT_READ | libc::PROT_WRITE, + libc::MAP_SHARED | populate, + file.as_raw_fd(), + offset, + ) + } + + pub fn map_copy(len: usize, file: &File, offset: u64, populate: bool) -> io::Result<MmapInner> { + let populate = if populate { MAP_POPULATE } else { 0 }; + MmapInner::new( + len, + libc::PROT_READ | libc::PROT_WRITE, + libc::MAP_PRIVATE | populate, + file.as_raw_fd(), + offset, + ) + } + + pub fn map_copy_read_only( + len: usize, + file: &File, + offset: u64, + populate: bool, + ) -> io::Result<MmapInner> { + let populate = if populate { MAP_POPULATE } else { 0 }; + MmapInner::new( + len, + libc::PROT_READ, + libc::MAP_PRIVATE | populate, + file.as_raw_fd(), + offset, + ) + } + + /// Open an anonymous memory map. + pub fn map_anon(len: usize, stack: bool) -> io::Result<MmapInner> { + let stack = if stack { MAP_STACK } else { 0 }; + MmapInner::new( + len, + libc::PROT_READ | libc::PROT_WRITE, + libc::MAP_PRIVATE | libc::MAP_ANON | stack, + -1, + 0, + ) + } + + pub fn flush(&self, offset: usize, len: usize) -> io::Result<()> { + let alignment = (self.ptr as usize + offset) % page_size(); + let offset = offset as isize - alignment as isize; + let len = len + alignment; + let result = + unsafe { libc::msync(self.ptr.offset(offset), len as libc::size_t, libc::MS_SYNC) }; + if result == 0 { + Ok(()) + } else { + Err(io::Error::last_os_error()) + } + } + + pub fn flush_async(&self, offset: usize, len: usize) -> io::Result<()> { + let alignment = (self.ptr as usize + offset) % page_size(); + let offset = offset as isize - alignment as isize; + let len = len + alignment; + let result = + unsafe { libc::msync(self.ptr.offset(offset), len as libc::size_t, libc::MS_ASYNC) }; + if result == 0 { + Ok(()) + } else { + Err(io::Error::last_os_error()) + } + } + + fn mprotect(&mut self, prot: libc::c_int) -> io::Result<()> { + unsafe { + let alignment = self.ptr as usize % page_size(); + let ptr = self.ptr.offset(-(alignment as isize)); + let len = self.len + alignment; + if libc::mprotect(ptr, len, prot) == 0 { + Ok(()) + } else { + Err(io::Error::last_os_error()) + } + } + } + + pub fn make_read_only(&mut self) -> io::Result<()> { + self.mprotect(libc::PROT_READ) + } + + pub fn make_exec(&mut self) -> io::Result<()> { + self.mprotect(libc::PROT_READ | libc::PROT_EXEC) + } + + pub fn make_mut(&mut self) -> io::Result<()> { + self.mprotect(libc::PROT_READ | libc::PROT_WRITE) + } + + #[inline] + pub fn ptr(&self) -> *const u8 { + self.ptr as *const u8 + } + + #[inline] + pub fn mut_ptr(&mut self) -> *mut u8 { + self.ptr as *mut u8 + } + + #[inline] + pub fn len(&self) -> usize { + self.len + } +} + +impl Drop for MmapInner { + fn drop(&mut self) { + let alignment = self.ptr as usize % page_size(); + unsafe { + assert!( + libc::munmap( + self.ptr.offset(-(alignment as isize)), + (self.len + alignment) as libc::size_t + ) == 0, + "unable to unmap mmap: {}", + io::Error::last_os_error() + ); + } + } +} + +unsafe impl Sync for MmapInner {} +unsafe impl Send for MmapInner {} + +fn page_size() -> usize { + unsafe { libc::sysconf(libc::_SC_PAGESIZE) as usize } +} |