Add /dev/zero, /dev/random, /dev/urandom, and /dev/arandom

src/libos/src/fs/dev_null.rs

@@ -1,35 +1,35 @@
 use super::*;
 
 #[derive(Debug)]
-pub struct NullFile;
+pub struct DevNull;
-
-impl File for NullFile {
-    fn read(&self, _buf: &mut [u8]) -> Result<usize, Error> {
-        unimplemented!()
-    }
 
+impl File for DevNull {
     fn write(&self, _buf: &[u8]) -> Result<usize, Error> {
-        Ok(0)
+        Ok(_buf.len())
-    }
-
-    fn read_at(&self, _offset: usize, _buf: &mut [u8]) -> Result<usize, Error> {
-        unimplemented!()
     }
 
     fn write_at(&self, _offset: usize, _buf: &[u8]) -> Result<usize, Error> {
-        unimplemented!()
+        Ok(_buf.len())
-    }
-
-    fn readv(&self, bufs: &mut [&mut [u8]]) -> Result<usize, Error> {
-        unimplemented!()
     }
 
     fn writev(&self, bufs: &[&[u8]]) -> Result<usize, Error> {
-        unimplemented!()
+        Ok(bufs.iter().map(|buf| buf.len()).sum())
+    }
+
+    fn read(&self, _buf: &mut [u8]) -> Result<usize, Error> {
+        errno!(EINVAL, "device not support reads")
+    }
+
+    fn read_at(&self, _offset: usize, _buf: &mut [u8]) -> Result<usize, Error> {
+        errno!(EINVAL, "device not support reads")
+    }
+
+    fn readv(&self, bufs: &mut [&mut [u8]]) -> Result<usize, Error> {
+        errno!(EINVAL, "device not support reads")
     }
 
     fn seek(&self, pos: SeekFrom) -> Result<off_t, Error> {
-        unimplemented!()
+        errno!(EINVAL, "device not support seeks")
     }
 
     fn metadata(&self) -> Result<Metadata, Error> {
@@ -37,19 +37,19 @@ impl File for NullFile {
     }
 
     fn set_len(&self, len: u64) -> Result<(), Error> {
-        unimplemented!()
+        errno!(EINVAL, "device not support resizing")
     }
 
     fn sync_all(&self) -> Result<(), Error> {
-        unimplemented!()
+        Ok(())
     }
 
     fn sync_data(&self) -> Result<(), Error> {
-        unimplemented!()
+        Ok(())
     }
 
     fn read_entry(&self) -> Result<String, Error> {
-        unimplemented!()
+        errno!(ENOTDIR, "device is not a directory")
     }
 
     fn as_any(&self) -> &Any {

src/libos/src/fs/dev_random.rs

@@ -0,0 +1,84 @@
+use super::*;
+
+#[derive(Debug)]
+pub struct DevRandom;
+
+extern "C" {
+    fn sgx_read_rand(rand_buf: *mut u8, buf_size: usize) -> sgx_status_t;
+}
+
+impl File for DevRandom {
+    fn read(&self, _buf: &mut [u8]) -> Result<usize, Error> {
+        let buf = _buf.as_mut_ptr();
+        let size = _buf.len();
+        let status = unsafe { sgx_read_rand(buf, size) };
+        if status != sgx_status_t::SGX_SUCCESS {
+            return errno!(EAGAIN, "failed to get random number from sgx");
+        }
+        Ok(size)
+    }
+
+    fn read_at(&self, _offset: usize, _buf: &mut [u8]) -> Result<usize, Error> {
+        self.read(_buf)
+    }
+
+    fn readv(&self, bufs: &mut [&mut [u8]]) -> Result<usize, Error> {
+        let mut total_nbytes = 0;
+        for buf in bufs {
+            match self.read(buf) {
+                Ok(this_nbytes) => {
+                    total_nbytes += this_nbytes;
+                }
+                Err(e) => {
+                    if total_nbytes > 0 {
+                        break
+                    }
+                    else {
+                        return Err(e);
+                    }
+                }
+            }
+        }
+        Ok(total_nbytes)
+    }
+
+    fn write(&self, _buf: &[u8]) -> Result<usize, Error> {
+        errno!(EINVAL, "device not support writes")
+    }
+
+    fn write_at(&self, _offset: usize, _buf: &[u8]) -> Result<usize, Error> {
+        errno!(EINVAL, "device not support writes")
+    }
+
+    fn writev(&self, bufs: &[&[u8]]) -> Result<usize, Error> {
+        errno!(EINVAL, "device not support writes")
+    }
+
+    fn seek(&self, pos: SeekFrom) -> Result<off_t, Error> {
+        errno!(EINVAL, "device not support seeks")
+    }
+
+    fn metadata(&self) -> Result<Metadata, Error> {
+        unimplemented!()
+    }
+
+    fn set_len(&self, len: u64) -> Result<(), Error> {
+        errno!(EINVAL, "device not support resizing")
+    }
+
+    fn sync_all(&self) -> Result<(), Error> {
+        Ok(())
+    }
+
+    fn sync_data(&self) -> Result<(), Error> {
+        Ok(())
+    }
+
+    fn read_entry(&self) -> Result<String, Error> {
+        errno!(ENOTDIR, "device is not a directory")
+    }
+
+    fn as_any(&self) -> &Any {
+        self
+    }
+}

src/libos/src/fs/dev_zero.rs

@@ -0,0 +1,65 @@
+use super::*;
+
+#[derive(Debug)]
+pub struct DevZero;
+
+impl File for DevZero {
+    fn read(&self, _buf: &mut [u8]) -> Result<usize, Error> {
+        for b in _buf.iter_mut() {
+            *b = 0;
+        }
+        Ok(_buf.len())
+    }
+
+    fn read_at(&self, _offset: usize, _buf: &mut [u8]) -> Result<usize, Error> {
+        self.read(_buf)
+    }
+
+    fn readv(&self, bufs: &mut [&mut [u8]]) -> Result<usize, Error> {
+        let mut total_nbytes = 0;
+        for buf in bufs {
+            total_nbytes += self.read(buf)?;
+        }
+        Ok(total_nbytes)
+    }
+
+    fn write(&self, _buf: &[u8]) -> Result<usize, Error> {
+        errno!(EINVAL, "device not support writes")
+    }
+
+    fn write_at(&self, _offset: usize, _buf: &[u8]) -> Result<usize, Error> {
+        errno!(EINVAL, "device not support writes")
+    }
+
+    fn writev(&self, bufs: &[&[u8]]) -> Result<usize, Error> {
+        errno!(EINVAL, "device not support writes")
+    }
+
+    fn seek(&self, pos: SeekFrom) -> Result<off_t, Error> {
+        errno!(EINVAL, "device not support seeks")
+    }
+
+    fn metadata(&self) -> Result<Metadata, Error> {
+        unimplemented!()
+    }
+
+    fn set_len(&self, len: u64) -> Result<(), Error> {
+        errno!(EINVAL, "device not support resizing")
+    }
+
+    fn sync_all(&self) -> Result<(), Error> {
+        Ok(())
+    }
+
+    fn sync_data(&self) -> Result<(), Error> {
+        Ok(())
+    }
+
+    fn read_entry(&self) -> Result<String, Error> {
+        errno!(ENOTDIR, "device is not a directory")
+    }
+
+    fn as_any(&self) -> &Any {
+        self
+    }
+}

src/libos/src/fs/mod.rs

@@ -12,7 +12,9 @@ pub use self::file_table::{FileDesc, FileTable};
 use self::inode_file::OpenOptions;
 pub use self::inode_file::{INodeExt, INodeFile, ROOT_INODE};
 pub use self::io_multiplexing::*;
-use self::null::NullFile;
+use self::dev_null::DevNull;
+use self::dev_zero::DevZero;
+use self::dev_random::DevRandom;
 pub use self::pipe::Pipe;
 pub use self::socket_file::{AsSocket, SocketFile};
 pub use self::unix_socket::{AsUnixSocket, UnixSocketFile};
@@ -25,7 +27,9 @@ mod file_table;
 mod hostfs;
 mod inode_file;
 mod io_multiplexing;
-mod null;
+mod dev_null;
+mod dev_zero;
+mod dev_random;
 mod pipe;
 mod sgx_impl;
 mod socket_file;
@@ -410,7 +414,13 @@ impl Process {
     /// Open a file on the process. But DO NOT add it to file table.
     pub fn open_file(&self, path: &str, flags: OpenFlags, mode: u32) -> Result<Box<File>, Error> {
         if path == "/dev/null" {
-            return Ok(Box::new(NullFile));
+            return Ok(Box::new(DevNull));
+        }
+        if path == "/dev/zero" {
+            return Ok(Box::new(DevZero));
+        }
+        if path == "/dev/random" || path == "/dev/urandom" || path == "/dev/arandom" {
+            return Ok(Box::new(DevRandom));
         }
         let inode = if flags.contains(OpenFlags::CREATE) {
             let (dir_path, file_name) = split_path(&path);

test/Makefile

@@ -4,8 +4,9 @@ PROJECT_DIR := $(realpath $(CUR_DIR)/../)
 # Dependencies: need to be compiled but not to run by any Makefile target
 TEST_DEPS := dev_null
 # Tests: need to be compiled and run by test-% target
-#TESTS := empty argv hello_world malloc mmap file getpid spawn pipe time truncate readdir mkdir link tls pthread uname rlimit client server server_epoll unix_socket cout hostfs cpuid rdtsc
+TESTS := empty argv hello_world malloc mmap file getpid spawn pipe time \
-TESTS := hello_world file readdir mkdir link hostfs
+	truncate readdir mkdir link tls pthread uname rlimit client server \
+	server_epoll unix_socket cout hostfs cpuid rdtsc device
 # Benchmarks: need to be compiled and run by bench-% target
 BENCHES := spawn_and_exit_latency pipe_throughput unix_socket_throughput
 

test/device/Makefile

@@ -0,0 +1,5 @@
+include ../test_common.mk
+
+EXTRA_C_FLAGS :=
+EXTRA_LINK_FLAGS :=
+BIN_ARGS :=

test/device/main.c

@@ -0,0 +1,91 @@
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+#include "test.h"
+
+// ============================================================================
+// Test utilities
+// ============================================================================
+
+static int check_file_readable(const char* filename) {
+    int fd;
+    char buf[512] = {0};
+    int len;
+    if ((fd = open(filename, O_RDONLY)) < 0) {
+        throw_error("failed to open the file");
+    }
+    if ((len = read(fd, buf, sizeof(buf))) != sizeof(buf)) {
+        throw_error("failed to read the file");
+    }
+    close(fd);
+    return 0;
+}
+
+static int check_file_writable(const char* filename) {
+    int fd;
+    char buf[512] = {0};
+    int len;
+    if ((fd = open(filename, O_WRONLY)) < 0) {
+        throw_error("failed to open the file");
+    }
+    if ((len = write(fd, buf, sizeof(buf))) != sizeof(buf)) {
+        throw_error("failed to read the file");
+    }
+    close(fd);
+    return 0;
+}
+
+// ============================================================================
+// Test cases for /dev/random, /dev/urandom, /dev/
+// ============================================================================
+
+int test_dev_null() {
+    if (check_file_writable("/dev/null")) {
+        throw_error("failed to write to /dev/null");
+    }
+    return 0;
+}
+
+int test_dev_zero() {
+    if (check_file_readable("/dev/zero")) {
+        throw_error("failed to read from /dev/null");
+    }
+    return 0;
+}
+
+int test_dev_random() {
+    if (check_file_readable("/dev/random")) {
+        throw_error("failed to read from /dev/random");
+    }
+    return 0;
+}
+
+int test_dev_urandom() {
+    if (check_file_readable("/dev/urandom")) {
+        throw_error("failed to read from /dev/urandom");
+    }
+    return 0;
+}
+
+int test_dev_arandom() {
+    if (check_file_readable("/dev/arandom")) {
+        throw_error("failed to read from /dev/arandom");
+    }
+    return 0;
+}
+
+// ============================================================================
+// Test suite
+// ============================================================================
+
+static test_case_t test_cases[] = {
+    TEST_CASE(test_dev_null),
+    TEST_CASE(test_dev_zero),
+    TEST_CASE(test_dev_random),
+    TEST_CASE(test_dev_urandom),
+    TEST_CASE(test_dev_arandom),
+};
+
+int main() {
+    return test_suite_run(test_cases, ARRAY_SIZE(test_cases));
+}