Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 317 insertions, 0 deletions

diff --git a/third_party/rust/memmap2/src/unix.rs b/third_party/rust/memmap2/src/unix.rs
new file mode 100644
index 0000000000..f691e68099
--- /dev/null
+++ b/third_party/rust/memmap2/src/unix.rs
@@ -0,0 +1,317 @@
+extern crate libc;
+
+use std::fs::File;
+use std::mem::ManuallyDrop;
+use std::os::unix::io::{FromRawFd, RawFd};
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::{io, ptr};
+
+use crate::advice::Advice;
+
+#[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;
+
+        // `libc::mmap` does not support zero-size mappings. POSIX defines:
+        //
+        // https://pubs.opengroup.org/onlinepubs/9699919799/functions/mmap.html
+        // > If `len` is zero, `mmap()` shall fail and no mapping shall be established.
+        //
+        // So if we would create such a mapping, crate a one-byte mapping instead:
+        let aligned_len = aligned_len.max(1);
+
+        // Note that in that case `MmapInner::len` is still set to zero,
+        // and `Mmap` will still dereferences to an empty slice.
+        //
+        // If this mapping is backed by an empty file, we create a mapping larger than the file.
+        // This is unusual but well-defined. On the same man page, POSIX further defines:
+        //
+        // > The `mmap()` function can be used to map a region of memory that is larger
+        // > than the current size of the object.
+        //
+        // (The object here is the file.)
+        //
+        // > Memory access within the mapping but beyond the current end of the underlying
+        // > objects may result in SIGBUS signals being sent to the process. The reason for this
+        // > is that the size of the object can be manipulated by other processes and can change
+        // > at any moment. The implementation should tell the application that a memory reference
+        // > is outside the object where this can be detected; otherwise, written data may be lost
+        // > and read data may not reflect actual data in the object.
+        //
+        // Because `MmapInner::len` is not incremented, this increment of `aligned_len`
+        // will not allow accesses past the end of the file and will not cause SIGBUS.
+        //
+        // (SIGBUS is still possible by mapping a non-empty file and then truncating it
+        // to a shorter size, but that is unrelated to this handling of empty files.)
+
+        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: RawFd, 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,
+            offset,
+        )
+    }
+
+    pub fn map_exec(len: usize, file: RawFd, 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,
+            offset,
+        )
+    }
+
+    pub fn map_mut(len: usize, file: RawFd, 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,
+            offset,
+        )
+    }
+
+    pub fn map_copy(len: usize, file: RawFd, 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,
+            offset,
+        )
+    }
+
+    pub fn map_copy_read_only(
+        len: usize,
+        file: RawFd,
+        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,
+            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;
+            let len = len.max(1);
+            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
+    }
+
+    pub fn advise(&self, advice: Advice, 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;
+        unsafe {
+            if libc::madvise(self.ptr.offset(offset), len, advice as i32) != 0 {
+                Err(io::Error::last_os_error())
+            } else {
+                Ok(())
+            }
+        }
+    }
+
+    pub fn lock(&self) -> io::Result<()> {
+        unsafe {
+            if libc::mlock(self.ptr, self.len) != 0 {
+                Err(io::Error::last_os_error())
+            } else {
+                Ok(())
+            }
+        }
+    }
+
+    pub fn unlock(&self) -> io::Result<()> {
+        unsafe {
+            if libc::munlock(self.ptr, self.len) != 0 {
+                Err(io::Error::last_os_error())
+            } else {
+                Ok(())
+            }
+        }
+    }
+}
+
+impl Drop for MmapInner {
+    fn drop(&mut self) {
+        let alignment = self.ptr as usize % page_size();
+        let len = self.len + alignment;
+        let len = len.max(1);
+        // Any errors during unmapping/closing are ignored as the only way
+        // to report them would be through panicking which is highly discouraged
+        // in Drop impls, c.f. https://github.com/rust-lang/lang-team/issues/97
+        unsafe {
+            let ptr = self.ptr.offset(-(alignment as isize));
+            libc::munmap(ptr, len as libc::size_t);
+        }
+    }
+}
+
+unsafe impl Sync for MmapInner {}
+unsafe impl Send for MmapInner {}
+
+fn page_size() -> usize {
+    static PAGE_SIZE: AtomicUsize = AtomicUsize::new(0);
+
+    match PAGE_SIZE.load(Ordering::Relaxed) {
+        0 => {
+            let page_size = unsafe { libc::sysconf(libc::_SC_PAGESIZE) as usize };
+
+            PAGE_SIZE.store(page_size, Ordering::Relaxed);
+
+            page_size
+        }
+        page_size => page_size,
+    }
+}
+
+pub fn file_len(file: RawFd) -> io::Result<u64> {
+    // SAFETY: We must not close the passed-in fd by dropping the File we create,
+    // we ensure this by immediately wrapping it in a ManuallyDrop.
+    unsafe {
+        let file = ManuallyDrop::new(File::from_raw_fd(file));
+        Ok(file.metadata()?.len())
+    }
+}