use crate::{Error, Result}; #[cfg(not(target_os = "android"))] use crate::NixPath; use crate::errno::Errno; #[cfg(not(target_os = "android"))] use crate::fcntl::OFlag; use libc::{self, c_int, c_void, size_t, off_t}; #[cfg(not(target_os = "android"))] use crate::sys::stat::Mode; use std::os::unix::io::RawFd; libc_bitflags!{ /// Desired memory protection of a memory mapping. pub struct ProtFlags: c_int { /// Pages cannot be accessed. PROT_NONE; /// Pages can be read. PROT_READ; /// Pages can be written. PROT_WRITE; /// Pages can be executed PROT_EXEC; /// Apply protection up to the end of a mapping that grows upwards. #[cfg(any(target_os = "android", target_os = "linux"))] PROT_GROWSDOWN; /// Apply protection down to the beginning of a mapping that grows downwards. #[cfg(any(target_os = "android", target_os = "linux"))] PROT_GROWSUP; } } libc_bitflags!{ /// Additional parameters for `mmap()`. pub struct MapFlags: c_int { /// Compatibility flag. Ignored. MAP_FILE; /// Share this mapping. Mutually exclusive with `MAP_PRIVATE`. MAP_SHARED; /// Create a private copy-on-write mapping. Mutually exclusive with `MAP_SHARED`. MAP_PRIVATE; /// Place the mapping at exactly the address specified in `addr`. MAP_FIXED; /// Synonym for `MAP_ANONYMOUS`. MAP_ANON; /// The mapping is not backed by any file. #[cfg(any(target_os = "android", target_os = "linux", target_os = "freebsd"))] MAP_ANONYMOUS; /// Put the mapping into the first 2GB of the process address space. #[cfg(any(all(any(target_os = "android", target_os = "linux"), any(target_arch = "x86", target_arch = "x86_64")), all(target_os = "linux", target_env = "musl", any(target_arch = "x86", target_arch = "x86_64")), all(target_os = "freebsd", target_pointer_width = "64")))] MAP_32BIT; /// Used for stacks; indicates to the kernel that the mapping should extend downward in memory. #[cfg(any(target_os = "android", target_os = "linux"))] MAP_GROWSDOWN; /// Compatibility flag. Ignored. #[cfg(any(target_os = "android", target_os = "linux"))] MAP_DENYWRITE; /// Compatibility flag. Ignored. #[cfg(any(target_os = "android", target_os = "linux"))] MAP_EXECUTABLE; /// Mark the mmaped region to be locked in the same way as `mlock(2)`. #[cfg(any(target_os = "android", target_os = "linux"))] MAP_LOCKED; /// Do not reserve swap space for this mapping. /// /// This was removed in FreeBSD 11. #[cfg(not(target_os = "freebsd"))] MAP_NORESERVE; /// Populate page tables for a mapping. #[cfg(any(target_os = "android", target_os = "linux"))] MAP_POPULATE; /// Only meaningful when used with `MAP_POPULATE`. Don't perform read-ahead. #[cfg(any(target_os = "android", target_os = "linux"))] MAP_NONBLOCK; /// Allocate the mapping using "huge pages." #[cfg(any(target_os = "android", target_os = "linux"))] MAP_HUGETLB; /// Make use of 64KB huge page (must be supported by the system) #[cfg(target_os = "linux")] MAP_HUGE_64KB; /// Make use of 512KB huge page (must be supported by the system) #[cfg(target_os = "linux")] MAP_HUGE_512KB; /// Make use of 1MB huge page (must be supported by the system) #[cfg(target_os = "linux")] MAP_HUGE_1MB; /// Make use of 2MB huge page (must be supported by the system) #[cfg(target_os = "linux")] MAP_HUGE_2MB; /// Make use of 8MB huge page (must be supported by the system) #[cfg(target_os = "linux")] MAP_HUGE_8MB; /// Make use of 16MB huge page (must be supported by the system) #[cfg(target_os = "linux")] MAP_HUGE_16MB; /// Make use of 32MB huge page (must be supported by the system) #[cfg(target_os = "linux")] MAP_HUGE_32MB; /// Make use of 256MB huge page (must be supported by the system) #[cfg(target_os = "linux")] MAP_HUGE_256MB; /// Make use of 512MB huge page (must be supported by the system) #[cfg(target_os = "linux")] MAP_HUGE_512MB; /// Make use of 1GB huge page (must be supported by the system) #[cfg(target_os = "linux")] MAP_HUGE_1GB; /// Make use of 2GB huge page (must be supported by the system) #[cfg(target_os = "linux")] MAP_HUGE_2GB; /// Make use of 16GB huge page (must be supported by the system) #[cfg(target_os = "linux")] MAP_HUGE_16GB; /// Lock the mapped region into memory as with `mlock(2)`. #[cfg(target_os = "netbsd")] MAP_WIRED; /// Causes dirtied data in the specified range to be flushed to disk only when necessary. #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))] MAP_NOSYNC; /// Rename private pages to a file. /// /// This was removed in FreeBSD 11. #[cfg(any(target_os = "dragonfly", target_os = "netbsd", target_os = "openbsd"))] MAP_RENAME; /// Region may contain semaphores. #[cfg(any(target_os = "dragonfly", target_os = "freebsd", target_os = "netbsd", target_os = "openbsd"))] MAP_HASSEMAPHORE; /// Region grows down, like a stack. #[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd", target_os = "linux"))] MAP_STACK; /// Pages in this mapping are not retained in the kernel's memory cache. #[cfg(any(target_os = "ios", target_os = "macos"))] MAP_NOCACHE; #[cfg(any(target_os = "ios", target_os = "macos"))] MAP_JIT; } } #[cfg(target_os = "linux")] libc_bitflags!{ /// Options for `mremap()`. pub struct MRemapFlags: c_int { /// Permit the kernel to relocate the mapping to a new virtual address, if necessary. MREMAP_MAYMOVE; /// Place the mapping at exactly the address specified in `new_address`. MREMAP_FIXED; } } libc_enum!{ /// Usage information for a range of memory to allow for performance optimizations by the kernel. /// /// Used by [`madvise`](./fn.madvise.html). #[repr(i32)] #[non_exhaustive] pub enum MmapAdvise { /// No further special treatment. This is the default. MADV_NORMAL, /// Expect random page references. MADV_RANDOM, /// Expect sequential page references. MADV_SEQUENTIAL, /// Expect access in the near future. MADV_WILLNEED, /// Do not expect access in the near future. MADV_DONTNEED, /// Free up a given range of pages and its associated backing store. #[cfg(any(target_os = "android", target_os = "linux"))] MADV_REMOVE, /// Do not make pages in this range available to the child after a `fork(2)`. #[cfg(any(target_os = "android", target_os = "linux"))] MADV_DONTFORK, /// Undo the effect of `MADV_DONTFORK`. #[cfg(any(target_os = "android", target_os = "linux"))] MADV_DOFORK, /// Poison the given pages. /// /// Subsequent references to those pages are treated like hardware memory corruption. #[cfg(any(target_os = "android", target_os = "linux"))] MADV_HWPOISON, /// Enable Kernel Samepage Merging (KSM) for the given pages. #[cfg(any(target_os = "android", target_os = "linux"))] MADV_MERGEABLE, /// Undo the effect of `MADV_MERGEABLE` #[cfg(any(target_os = "android", target_os = "linux"))] MADV_UNMERGEABLE, /// Preserve the memory of each page but offline the original page. #[cfg(any(target_os = "android", all(target_os = "linux", any( target_arch = "aarch64", target_arch = "arm", target_arch = "ppc", target_arch = "s390x", target_arch = "x86", target_arch = "x86_64", target_arch = "sparc64"))))] MADV_SOFT_OFFLINE, /// Enable Transparent Huge Pages (THP) for pages in the given range. #[cfg(any(target_os = "android", target_os = "linux"))] MADV_HUGEPAGE, /// Undo the effect of `MADV_HUGEPAGE`. #[cfg(any(target_os = "android", target_os = "linux"))] MADV_NOHUGEPAGE, /// Exclude the given range from a core dump. #[cfg(any(target_os = "android", target_os = "linux"))] MADV_DONTDUMP, /// Undo the effect of an earlier `MADV_DONTDUMP`. #[cfg(any(target_os = "android", target_os = "linux"))] MADV_DODUMP, /// Specify that the application no longer needs the pages in the given range. MADV_FREE, /// Request that the system not flush the current range to disk unless it needs to. #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))] MADV_NOSYNC, /// Undoes the effects of `MADV_NOSYNC` for any future pages dirtied within the given range. #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))] MADV_AUTOSYNC, /// Region is not included in a core file. #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))] MADV_NOCORE, /// Include region in a core file #[cfg(any(target_os = "dragonfly", target_os = "freebsd"))] MADV_CORE, #[cfg(any(target_os = "freebsd"))] MADV_PROTECT, /// Invalidate the hardware page table for the given region. #[cfg(target_os = "dragonfly")] MADV_INVAL, /// Set the offset of the page directory page to `value` for the virtual page table. #[cfg(target_os = "dragonfly")] MADV_SETMAP, /// Indicates that the application will not need the data in the given range. #[cfg(any(target_os = "ios", target_os = "macos"))] MADV_ZERO_WIRED_PAGES, #[cfg(any(target_os = "ios", target_os = "macos"))] MADV_FREE_REUSABLE, #[cfg(any(target_os = "ios", target_os = "macos"))] MADV_FREE_REUSE, #[cfg(any(target_os = "ios", target_os = "macos"))] MADV_CAN_REUSE, } } libc_bitflags!{ /// Configuration flags for `msync`. pub struct MsFlags: c_int { /// Schedule an update but return immediately. MS_ASYNC; /// Invalidate all cached data. MS_INVALIDATE; /// Invalidate pages, but leave them mapped. #[cfg(any(target_os = "ios", target_os = "macos"))] MS_KILLPAGES; /// Deactivate pages, but leave them mapped. #[cfg(any(target_os = "ios", target_os = "macos"))] MS_DEACTIVATE; /// Perform an update and wait for it to complete. MS_SYNC; } } libc_bitflags!{ /// Flags for `mlockall`. pub struct MlockAllFlags: c_int { /// Lock pages that are currently mapped into the address space of the process. MCL_CURRENT; /// Lock pages which will become mapped into the address space of the process in the future. MCL_FUTURE; } } /// Locks all memory pages that contain part of the address range with `length` /// bytes starting at `addr`. /// /// Locked pages never move to the swap area. /// /// # Safety /// /// `addr` must meet all the requirements described in the `mlock(2)` man page. pub unsafe fn mlock(addr: *const c_void, length: size_t) -> Result<()> { Errno::result(libc::mlock(addr, length)).map(drop) } /// Unlocks all memory pages that contain part of the address range with /// `length` bytes starting at `addr`. /// /// # Safety /// /// `addr` must meet all the requirements described in the `munlock(2)` man /// page. pub unsafe fn munlock(addr: *const c_void, length: size_t) -> Result<()> { Errno::result(libc::munlock(addr, length)).map(drop) } /// Locks all memory pages mapped into this process' address space. /// /// Locked pages never move to the swap area. /// /// # Safety /// /// `addr` must meet all the requirements described in the `mlockall(2)` man /// page. pub fn mlockall(flags: MlockAllFlags) -> Result<()> { unsafe { Errno::result(libc::mlockall(flags.bits())) }.map(drop) } /// Unlocks all memory pages mapped into this process' address space. pub fn munlockall() -> Result<()> { unsafe { Errno::result(libc::munlockall()) }.map(drop) } /// allocate memory, or map files or devices into memory /// /// # Safety /// /// See the `mmap(2)` man page for detailed requirements. pub unsafe fn mmap(addr: *mut c_void, length: size_t, prot: ProtFlags, flags: MapFlags, fd: RawFd, offset: off_t) -> Result<*mut c_void> { let ret = libc::mmap(addr, length, prot.bits(), flags.bits(), fd, offset); if ret == libc::MAP_FAILED { Err(Error::from(Errno::last())) } else { Ok(ret) } } /// Expands (or shrinks) an existing memory mapping, potentially moving it at /// the same time. /// /// # Safety /// /// See the `mremap(2)` [man page](https://man7.org/linux/man-pages/man2/mremap.2.html) for /// detailed requirements. #[cfg(target_os = "linux")] pub unsafe fn mremap( addr: *mut c_void, old_size: size_t, new_size: size_t, flags: MRemapFlags, new_address: Option<* mut c_void>, ) -> Result<*mut c_void> { let ret = libc::mremap(addr, old_size, new_size, flags.bits(), new_address.unwrap_or(std::ptr::null_mut())); if ret == libc::MAP_FAILED { Err(Error::from(Errno::last())) } else { Ok(ret) } } /// remove a mapping /// /// # Safety /// /// `addr` must meet all the requirements described in the `munmap(2)` man /// page. pub unsafe fn munmap(addr: *mut c_void, len: size_t) -> Result<()> { Errno::result(libc::munmap(addr, len)).map(drop) } /// give advice about use of memory /// /// # Safety /// /// See the `madvise(2)` man page. Take special care when using /// `MmapAdvise::MADV_FREE`. pub unsafe fn madvise(addr: *mut c_void, length: size_t, advise: MmapAdvise) -> Result<()> { Errno::result(libc::madvise(addr, length, advise as i32)).map(drop) } /// Set protection of memory mapping. /// /// See [`mprotect(3)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mprotect.html) for /// details. /// /// # Safety /// /// Calls to `mprotect` are inherently unsafe, as changes to memory protections can lead to /// SIGSEGVs. /// /// ``` /// # use nix::libc::size_t; /// # use nix::sys::mman::{mmap, mprotect, MapFlags, ProtFlags}; /// # use std::ptr; /// const ONE_K: size_t = 1024; /// let mut slice: &mut [u8] = unsafe { /// let mem = mmap(ptr::null_mut(), ONE_K, ProtFlags::PROT_NONE, /// MapFlags::MAP_ANON | MapFlags::MAP_PRIVATE, -1, 0).unwrap(); /// mprotect(mem, ONE_K, ProtFlags::PROT_READ | ProtFlags::PROT_WRITE).unwrap(); /// std::slice::from_raw_parts_mut(mem as *mut u8, ONE_K) /// }; /// assert_eq!(slice[0], 0x00); /// slice[0] = 0xFF; /// assert_eq!(slice[0], 0xFF); /// ``` pub unsafe fn mprotect(addr: *mut c_void, length: size_t, prot: ProtFlags) -> Result<()> { Errno::result(libc::mprotect(addr, length, prot.bits())).map(drop) } /// synchronize a mapped region /// /// # Safety /// /// `addr` must meet all the requirements described in the `msync(2)` man /// page. pub unsafe fn msync(addr: *mut c_void, length: size_t, flags: MsFlags) -> Result<()> { Errno::result(libc::msync(addr, length, flags.bits())).map(drop) } #[cfg(not(target_os = "android"))] pub fn shm_open(name: &P, flag: OFlag, mode: Mode) -> Result { let ret = name.with_nix_path(|cstr| { #[cfg(any(target_os = "macos", target_os = "ios"))] unsafe { libc::shm_open(cstr.as_ptr(), flag.bits(), mode.bits() as libc::c_uint) } #[cfg(not(any(target_os = "macos", target_os = "ios")))] unsafe { libc::shm_open(cstr.as_ptr(), flag.bits(), mode.bits() as libc::mode_t) } })?; Errno::result(ret) } #[cfg(not(target_os = "android"))] pub fn shm_unlink(name: &P) -> Result<()> { let ret = name.with_nix_path(|cstr| { unsafe { libc::shm_unlink(cstr.as_ptr()) } })?; Errno::result(ret).map(drop) }