Enable libc's printf

src/libos/src/file.rs

@@ -185,8 +185,6 @@ impl SgxFileInner {
         for buf in bufs {
             match file.write(buf) {
                 Ok(this_bytes) => {
-                    if this_bytes == 0 { break; }
-
                     total_bytes += this_bytes;
                     if this_bytes < buf.len() { break; }
                 }
@@ -221,8 +219,6 @@ impl SgxFileInner {
         for buf in bufs {
             match file.read(buf) {
                 Ok(this_bytes) => {
-                    if this_bytes == 0 { break; }
-
                     total_bytes += this_bytes;
                     if this_bytes < buf.len() { break; }
                 }
@@ -282,7 +278,6 @@ impl File for StdoutFile {
         for buf in bufs {
             match guard.write(buf) {
                 Ok(this_len) => {
-                    if this_len == 0 { break; }
                     total_bytes += this_len;
                     if this_len < buf.len() { break; }
                 }
@@ -352,7 +347,6 @@ impl File for StdinFile {
         for buf in bufs {
             match guard.read(buf) {
                 Ok(this_len) => {
-                    if this_len == 0 { break; }
                     total_bytes += this_len;
                     if this_len < buf.len() { break; }
                 }

src/libos/src/lib.rs

@@ -24,6 +24,7 @@ use std::panic;
 use sgx_types::*;
 use sgx_trts::libc;
 
+#[macro_use]
 mod prelude;
 mod elf_helper;
 mod errno;

src/libos/src/prelude.rs

@@ -21,3 +21,9 @@ pub use errno::Error as Error;
 pub use errno::Errno;
 
 pub use fs::off_t;
+
+macro_rules! debug_trace {
+    () => {
+        println!("> Line = {}, File = {}", line!(), file!())
+    };
+}

src/libos/src/syscall.rs

@@ -92,7 +92,7 @@ fn do_writev(fd: c_int, iov: *const iovec_t, count: c_int)
             let buf = unsafe {
                 std::slice::from_raw_parts(iov.base as * const u8, iov.len)
             };
-            bufs_vec[iov_i] = buf;
+            bufs_vec.push(buf);
         }
         bufs_vec
     };
@@ -122,7 +122,7 @@ fn do_readv(fd: c_int, iov: *mut iovec_t, count: c_int)
             let buf = unsafe {
                 std::slice::from_raw_parts_mut(iov.base as * mut u8, iov.len)
             };
-            bufs_vec[iov_i] = buf;
+            bufs_vec.push(buf);
         }
         bufs_vec
     };

test/hello_world/main.c

@@ -1,9 +1,10 @@
 #include <unistd.h>
 #include <string.h>
+#include <stdio.h>
 
 static const char* msg = "Hello World\n";
 
 int main(void) {
-    write(1, msg, strlen(msg) + 1);
+    printf("%s", msg);
     return 0;
 }