mmap skeleton

RustPython · youknowone · Jun 14, 2022 · Jun 14, 2022 · Mar 8, 2022 · May 28, 2022
commit cc4583ef505ff69fcb9463f901f42b5e11f85de6
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/stdlib/Cargo.toml b/stdlib/Cargo.toml
@@ -63,6 +63,8 @@ ahash = "0.7.6"
 libz-sys = { version = "1.1.5", optional = true }
 num_enum = "0.5.7"
 ascii = "1.0.0"
+memmap2 = "0.5.0"
+page_size = "0.4.2"
 
 [target.'cfg(all(unix, not(target_os = "redox")))'.dependencies]
 termios = "0.3.3"

diff --git a/stdlib/src/lib.rs b/stdlib/src/lib.rs
@@ -16,6 +16,8 @@ mod gc;
 mod hashlib;
 mod json;
 mod math;
+#[cfg(unix)]
+mod mmap;
 mod platform;
 mod pyexpat;
 mod pystruct;
@@ -125,6 +127,7 @@ pub fn get_module_inits() -> impl Iterator<Item = (Cow<'static, str>, StdlibInit
         {
             "_posixsubprocess" => posixsubprocess::make_module,
             "syslog" => syslog::make_module,
+            "mmap" => mmap::make_module,
         }
         #[cfg(target_os = "macos")]
         {

diff --git a/stdlib/src/mmap.rs b/stdlib/src/mmap.rs
@@ -0,0 +1,156 @@
+pub(crate) use mmap::make_module;
+
+#[pymodule]
+mod mmap {
+    use crate::vm::{
+        builtins::PyTypeRef, convert::ToPyResult, function::OptionalArg, types::Constructor,
+        FromArgs, PyObject, PyPayload, PyResult, TryFromBorrowedObject, VirtualMachine,
+    };
+    use memmap2::{MmapMut, MmapOptions};
+
+    #[repr(C)]
+    #[derive(PartialEq, Eq, Debug)]
+    enum AccessMode {
+        Default = 0,
+        Read = 1,
+        Write = 2,
+        Copy = 3,
+    }
+
+    impl TryFromBorrowedObject for AccessMode {
+        fn try_from_borrowed_object(vm: &VirtualMachine, obj: &PyObject) -> PyResult<Self> {
+            let i = u32::try_from_borrowed_object(vm, obj)?;
+            Ok(match i {
+                0 => Self::Default,
+                1 => Self::Read,
+                2 => Self::Write,
+                3 => Self::Copy,
+                _ => return Err(vm.new_value_error("Not a valid AccessMode value".to_owned())),
+            })
+        }
+    }
+
+    #[pyattr]
+    use libc::{MAP_ANON, MAP_ANONYMOUS, MAP_PRIVATE, MAP_SHARED, PROT_READ, PROT_WRITE};
+    #[pyattr]
+    const ACCESS_DEFAULT: u32 = AccessMode::Default as u32;
+    #[pyattr]
+    const ACCESS_READ: u32 = AccessMode::Read as u32;
+    #[pyattr]
+    const ACCESS_WRITE: u32 = AccessMode::Write as u32;
+    #[pyattr]
+    const ACCESS_COPY: u32 = AccessMode::Copy as u32;
+
+    #[pyattr(name = "PAGESIZE")]
+    fn pagesize(vm: &VirtualMachine) -> usize {
+        page_size::get()
+    }
+
+    #[pyattr]
+    #[pyclass(name = "mmap")]
+    #[derive(Debug, PyPayload)]
+    struct PyMmap {
+        mmap: MmapMut,
+        exports: usize,
+        //     PyObject *weakreflist;
+        access: AccessMode,
+    }
+
+    #[derive(FromArgs)]
+    struct MmapNewArgs {
+        #[pyarg(any)]
+        fileno: std::os::unix::io::RawFd,
+        #[pyarg(any)]
+        length: isize,
+        #[pyarg(any, default = "MAP_SHARED")]
+        flags: libc::c_int,
+        #[pyarg(any, default = "PROT_WRITE|PROT_READ")]
+        prot: libc::c_int,
+        #[pyarg(any, default = "AccessMode::Default")]
+        access: AccessMode,
+        #[pyarg(any, default = "0")]
+        offset: u64,
+    }
+
+    impl Constructor for PyMmap {
+        type Args = MmapNewArgs;
+
+        fn py_new(
+            cls: PyTypeRef,
+            MmapNewArgs {
+                fileno: fd,
+                length,
+                flags,
+                prot,
+                access,
+                offset,
+            }: Self::Args,
+            vm: &VirtualMachine,
+        ) -> PyResult {
+            if length < 0 {
+                return Err(
+                    vm.new_overflow_error("memory mapped length must be positive".to_owned())
+                );
+            }
+            // if offset < 0 {
+            //     return Err(vm.new_overflow_error("memory mapped offset must be positive".to_owned()));
+            // }
+            if (access != AccessMode::Default)
+                && ((flags != MAP_SHARED) || (prot != (PROT_WRITE | PROT_READ)))
+            {
+                return Err(vm.new_value_error(
+                    "mmap can't specify both access and flags, prot.".to_owned(),
+                ));
+            }
+
+            let (flags, prot, access) = match access {
+                AccessMode::Read => (MAP_SHARED, PROT_READ, access),
+                AccessMode::Write => (MAP_SHARED, PROT_READ | PROT_WRITE, access),
+                AccessMode::Copy => (MAP_PRIVATE, PROT_READ | PROT_WRITE, access),
+                AccessMode::Default => {
+                    let access = if (prot & PROT_READ) != 0 && (prot & PROT_WRITE) != 0 {
+                        access
+                    } else if (prot & PROT_WRITE) != 0 {
+                        AccessMode::Write
+                    } else {
+                        AccessMode::Read
+                    };
+                    (flags, prot, access)
+                }
+                _ => return Err(vm.new_value_error("mmap invalid access parameter.".to_owned())),
+            };
+
+            let mut mmap_opt = MmapOptions::new();
+            let mmap_opt = mmap_opt.offset(offset);
+            // .len(map_size)
+            let mmap = match access {
+                AccessMode::Write => unsafe { mmap_opt.map_mut(fd) },
+                // AccessMode::Read => mmap_opt.map(fd),
+                AccessMode::Copy => unsafe { mmap_opt.map_copy(fd) },
+                _ => unreachable!("access must be decided before here"),
+            }
+            .map_err(|_| vm.new_value_error("FIXME: mmap error".to_owned()))?;
+
+            let m_obj = Self {
+                mmap,
+                exports: 0,
+                access,
+            };
+
+            m_obj.to_pyresult(vm)
+        }
+    }
+
+    #[pyimpl]
+    impl PyMmap {
+        #[pymethod]
+        fn close(&self) -> PyResult<()> {
+            if self.exports > 0 {
+                // PyErr_SetString(PyExc_BufferError, "cannot close "\
+                // "exported pointers exist");
+            }
+            // self.mmap = MmapMut::map_anon(0).unwrap();
+            Ok(())
+        }
+    }
+}