Fix posix behavior for windows & raw mappings

Author: elast0ny

src/lib.rs

@@ -52,6 +52,7 @@ pub struct ShmemConf {
     overwrite_flink: bool,
     flink_path: Option<PathBuf>,
     size: usize,
+    ext: os_impl::ShmemConfExt,
 }
 impl Drop for ShmemConf {
     fn drop(&mut self) {
@@ -184,6 +185,7 @@ impl ShmemConf {
         let mut retry = 0;
         loop {
             let unique_id = if let Some(ref unique_id) = self.os_id {
+                retry = 5;
                 unique_id.as_str()
             } else {
                 let flink_path = self.flink_path.as_ref().unwrap();
@@ -202,7 +204,7 @@ impl ShmemConf {
                 flink_uid.as_str()
             };
 
-            match os_impl::open_mapping(unique_id, self.size) {
+            match os_impl::open_mapping(unique_id, self.size, &self.ext) {
                 Ok(m) => {
                     self.size = m.map_size;
                     self.owner = false;

src/unix.rs

@@ -9,6 +9,9 @@ use nix::unistd::{close, ftruncate};
 
 use crate::ShmemError;
 
+#[derive(Clone, Default)]
+pub struct ShmemConfExt;
+
 pub struct MapData {
     //On linux, you must shm_unlink() the object created for the mapping. It wont disappear automatically.
     owner: bool,
@@ -145,7 +148,7 @@ pub fn create_mapping(unique_id: &str, map_size: usize) -> Result<MapData, Shmem
 }
 
 /// Opens an existing mapping specified by its uid
-pub fn open_mapping(unique_id: &str, _map_size: usize) -> Result<MapData, ShmemError> {
+pub fn open_mapping(unique_id: &str, _map_size: usize, _ext: &ShmemConfExt) -> Result<MapData, ShmemError> {
     //Open shared memory
     debug!("Openning persistent mapping at {}", unique_id);
     let shmem_fd = match shm_open(

src/windows.rs

@@ -3,11 +3,24 @@ use std::io::ErrorKind;
 use std::os::windows::{fs::OpenOptionsExt, io::AsRawHandle};
 use std::path::PathBuf;
 
-use crate::log::*;
+use crate::{log::*, ShmemConf};
 use win_sys::*;
 
 use crate::ShmemError;
 
+#[derive(Clone, Default)]
+pub struct ShmemConfExt {
+    allow_raw: bool,
+}
+
+impl ShmemConf {
+    /// If set to true, enables openning raw shared memory that is not managed by this crate
+    pub fn allow_raw(mut self, allow: bool) -> Self {
+        self.ext.allow_raw = allow;
+        self
+    }
+}
+
 pub struct MapData {
     owner: bool,
 
@@ -118,7 +131,12 @@ fn get_tmp_dir() -> Result<PathBuf, ShmemError> {
     }
 }
 
-fn new_map(unique_id: &str, map_size: usize, create: bool) -> Result<MapData, ShmemError> {
+fn new_map(
+    unique_id: &str,
+    mut map_size: usize,
+    create: bool,
+    allow_raw: bool,
+) -> Result<MapData, ShmemError> {
     // Create file to back the shared memory
     let mut file_path = get_tmp_dir()?;
     file_path.push(unique_id.trim_start_matches('/'));
@@ -188,6 +206,8 @@ fn new_map(unique_id: &str, map_size: usize, create: bool) -> Result<MapData, Sh
         Err(e) => {
             if create {
                 return Err(ShmemError::MapCreateFailed(e.raw_os_error().unwrap() as _));
+            } else if !allow_raw {
+                return Err(ShmemError::MapOpenFailed(ERROR_FILE_NOT_FOUND.0));
             }
 
             // This may be a mapping that isnt managed by this crate
@@ -248,10 +268,14 @@ fn new_map(unique_id: &str, map_size: usize, create: bool) -> Result<MapData, Sh
 
 //Creates a mapping specified by the uid and size
 pub fn create_mapping(unique_id: &str, map_size: usize) -> Result<MapData, ShmemError> {
-    new_map(unique_id, map_size, true)
+    new_map(unique_id, map_size, true, false)
 }
 
 //Opens an existing mapping specified by its uid
-pub fn open_mapping(unique_id: &str, map_size: usize) -> Result<MapData, ShmemError> {
-    new_map(unique_id, map_size, false)
+pub fn open_mapping(
+    unique_id: &str,
+    map_size: usize,
+    ext: &ShmemConfExt,
+) -> Result<MapData, ShmemError> {
+    new_map(unique_id, map_size, false, ext.allow_raw)
 }