Support O_CLOEXEC on open() or pipe2()

src/libos/include/syscall.h

@@ -18,6 +18,7 @@ extern ssize_t occlum_readv(int fd, struct iovec* iov, int count);
 extern ssize_t occlum_writev(int fd, const struct iovec* iov, int count);
 extern off_t occlum_lseek(int fd, off_t offset, int whence);
 extern int occlum_pipe(int fds[2]);
+extern int occlum_pipe2(int fds[2], int flags);
 
 extern int occlum_spawn(int* child_pid, const char* path,
                         const char** argv,

src/libos/src/fs/file_table.rs

@@ -4,71 +4,100 @@ use {std};
 
 pub type FileDesc = u32;
 
-// Invariant 1: fd < max_fd, where fd is any fd in the table
-// Invariant 2: max_fd = table.size()
-// Invariant 3: num_fds <= table.size()
-#[derive(Clone, Debug, Default)]
+#[derive(Debug, Default)]
 #[repr(C)]
 pub struct FileTable {
-    table: Vec<Option<FileRef>>,
-    max_fd: FileDesc,
-    num_fds: u32,
+    table: Vec<Option<FileTableEntry>>,
+    num_fds: usize,
 }
 
+#[derive(Debug, Clone)]
+struct FileTableEntry {
+    file: FileRef,
+    close_on_spawn: bool,
+}
+
+
 impl FileTable {
     pub fn new() -> FileTable {
         FileTable {
-            table: Vec::with_capacity(0),
-            max_fd: 0,
+            table: Vec::with_capacity(4),
             num_fds: 0,
         }
     }
 
-    pub fn put(&mut self, file: FileRef) -> FileDesc {
+    pub fn put(&mut self, file: FileRef, close_on_spawn: bool) -> FileDesc {
         let mut table = &mut self.table;
 
-        let free_fd = if self.num_fds < self.max_fd {
-            table.iter().enumerate()
-                .find(|&(idx, opt)| opt.is_none()).unwrap().0 as FileDesc
+        let min_free_fd = if self.num_fds < table.len() {
+            table.iter().enumerate().find(|&(idx, opt)| opt.is_none())
+                .unwrap().0
         } else {
             table.push(None);
-            self.max_fd += 1;
-            self.num_fds
+            table.len() - 1
         };
 
-        table[free_fd as usize] = Some(file);
+        table[min_free_fd as usize] = Some(FileTableEntry::new(file,
+                                                               close_on_spawn));
         self.num_fds += 1;
 
-        free_fd
+        min_free_fd as FileDesc
     }
 
     pub fn get(&self, fd: FileDesc) -> Option<FileRef> {
-        if fd >= self.max_fd {
+        if fd as usize >= self.table.len() {
             return None;
         }
 
         let table = &self.table;
-        table[fd as usize].as_ref().map(|file_ref| file_ref.clone())
+        table[fd as usize].as_ref().map(|entry| entry.file.clone())
     }
 
     pub fn del(&mut self, fd: FileDesc) -> Option<FileRef> {
-        if fd >= self.max_fd {
+        if fd as usize >= self.table.len() {
             return None;
         }
 
-        let mut del_file = None;
+        let mut del_entry = None;
         let table = &mut self.table;
-        std::mem::swap(&mut del_file, &mut table[fd as usize]);
-        if del_file.is_none() {
-            return None;
-        }
-
+        std::mem::swap(&mut del_entry, &mut table[fd as usize]);
         self.num_fds -= 1;
-        if fd + 1 == self.max_fd {
-            self.max_fd = table.iter().enumerate().rev()
-                .find(|&(idx, opt)| opt.is_some())
-                .map_or(0, |(max_used_fd,opt)| max_used_fd + 1) as FileDesc;
-        }
-        del_file
+        del_entry.map(|entry| entry.file)
+    }
+}
+
+impl Clone for FileTable {
+    fn clone(&self) -> FileTable {
+        // Only clone file descriptors that are not close-on-spawn
+        let mut num_cloned_fds = 0;
+        let cloned_table = self.table.iter().map(|entry| {
+            match entry {
+                Some(file_table_entry) => {
+                    match file_table_entry.close_on_spawn {
+                        false => {
+                            num_cloned_fds += 1;
+                            Some(file_table_entry.clone())
+                        }
+                        true => None
+                    }
+                },
+                None => None
+            }
+        }).collect();
+
+        FileTable {
+            table: cloned_table,
+            num_fds: num_cloned_fds,
+        }
+    }
+}
+
+
+impl FileTableEntry {
+    fn new(file: FileRef, close_on_spawn: bool) -> FileTableEntry {
+        FileTableEntry {
+            file,
+            close_on_spawn,
+        }
     }
 }

src/libos/src/fs/mod.rs

@@ -17,6 +17,7 @@ pub const O_RDWR   : u32 = 0x00000002;
 pub const O_CREAT  : u32 = 0x00000040;
 pub const O_TRUNC  : u32 = 0x00000200;
 pub const O_APPEND : u32 = 0x00000400;
+pub const O_CLOEXEC: u32 = 0x00080000;
 
 // TODO: use the type defined in Rust libc.
 //
@@ -54,10 +55,12 @@ pub fn do_open(path: &str, flags: u32, mode: u32) -> Result<FileDesc, Error> {
     let file_ref : Arc<Box<File>> = Arc::new(Box::new(
             SgxFile::new(sgx_file, is_readable, is_writable, is_append)?));
 
-    let current_ref = process::get_current();
-    let mut current_process = current_ref.lock().unwrap();
-    let fd = current_process.get_files_mut().put(file_ref);
-
+    let fd = {
+        let current_ref = process::get_current();
+        let mut current = current_ref.lock().unwrap();
+        let close_on_spawn = flags & O_CLOEXEC != 0;
+        current.get_files_mut().put(file_ref, close_on_spawn)
+    };
     Ok(fd)
 }
 
@@ -111,13 +114,16 @@ pub fn do_close(fd: FileDesc) -> Result<(), Error> {
     }
 }
 
-pub fn do_pipe() -> Result<[FileDesc; 2], Error> {
+pub fn do_pipe2(flags: u32) -> Result<[FileDesc; 2], Error> {
     let current_ref = process::get_current();
     let mut current = current_ref.lock().unwrap();
     let pipe = Pipe::new()?;
 
     let mut file_table = current.get_files_mut();
-    let reader_fd = file_table.put(Arc::new(Box::new(pipe.reader)));
-    let writer_fd = file_table.put(Arc::new(Box::new(pipe.writer)));
+    let close_on_spawn = flags & O_CLOEXEC != 0;
+    let reader_fd = file_table.put(Arc::new(Box::new(pipe.reader)),
+                                   close_on_spawn);
+    let writer_fd = file_table.put(Arc::new(Box::new(pipe.writer)),
+                                   close_on_spawn);
     Ok([reader_fd, writer_fd])
 }

src/libos/src/process/spawn/mod.rs

@@ -80,9 +80,9 @@ fn init_files(parent_ref: &ProcessRef) -> Result<FileTable, Error> {
     let stdout : Arc<Box<File>> = Arc::new(Box::new(StdoutFile::new()));
     // TODO: implement and use a real stderr
     let stderr = stdout.clone();
-    file_table.put(stdin);
-    file_table.put(stdout);
-    file_table.put(stderr);
+    file_table.put(stdin, false);
+    file_table.put(stdout, false);
+    file_table.put(stderr, false);
     Ok(file_table)
 }
 

src/libos/src/syscall/mod.rs

@@ -195,6 +195,17 @@ fn do_brk(new_brk_addr: *const c_void) -> Result<*const c_void, Error> {
     vm::do_brk(new_brk_addr).map(|ret_brk_addr| ret_brk_addr as *const c_void)
 }
 
+fn do_pipe2(fds_u: *mut c_int, flags: c_int) -> Result<(), Error> {
+    check_mut_array_from_user(fds_u, 2)?;
+    // TODO: how to deal with open flags???
+    let fds = fs::do_pipe2(flags as u32)?;
+    unsafe {
+        *fds_u.offset(0) = fds[0] as c_int;
+        *fds_u.offset(1) = fds[1] as c_int;
+    }
+    Ok(())
+}
+
 
 const MAP_FAILED : *const c_void = ((-1) as i64) as *const c_void;
 
@@ -237,19 +248,14 @@ pub extern "C" fn occlum_brk(addr: *const c_void) ->  *const c_void {
     }
 }
 
-fn do_pipe(fds_u: *mut c_int) -> Result<(), Error> {
-    check_mut_array_from_user(fds_u, 2)?;
-    let fds = fs::do_pipe()?;
-    unsafe {
-        *fds_u.offset(0) = fds[0] as c_int;
-        *fds_u.offset(1) = fds[1] as c_int;
-    }
-    Ok(())
+#[no_mangle]
+pub extern "C" fn occlum_pipe(fds: *mut c_int) ->  c_int {
+    occlum_pipe2(fds, 0)
 }
 
 #[no_mangle]
-pub extern "C" fn occlum_pipe(fds: *mut c_int) ->  c_int {
-    match do_pipe(fds) {
+pub extern "C" fn occlum_pipe2(fds: *mut c_int, flags: c_int) ->  c_int {
+    match do_pipe2(fds, flags) {
         Ok(()) => {
             0
         },

src/libos/src/syscall/syscall_entry.c

@@ -119,6 +119,12 @@ long dispatch_syscall(int num, long arg0, long arg1, long arg2, long arg3, long
         ret = (long) occlum_pipe(fds);
         break;
     }
+    case SYS_pipe2: {
+        DECL_SYSCALL_ARG(int*, fds, arg0);
+        DECL_SYSCALL_ARG(int, flags, arg1);
+        ret = (long) occlum_pipe2(fds, flags);
+        break;
+    }
     default:
         ret = occlum_unknown(num);
         break;