Provides some of the missing POSIX file syscalls

src/untrusted/irt/irt_fdio.c

Index: src/untrusted/irt/irt_fdio.c
diff --git a/src/untrusted/irt/irt_fdio.c b/src/untrusted/irt/irt_fdio.c
index a8b52bbe70e9dfaa049cc3c6436daae4e5af1e8c..e4c1318a0ed6d0a9691abec06ef3d15c0d622732 100644
--- a/src/untrusted/irt/irt_fdio.c
+++ b/src/untrusted/irt/irt_fdio.c
@@ -5,6 +5,7 @@
  */
 
 #include "native_client/src/untrusted/irt/irt.h"
+#include "native_client/src/untrusted/irt/irt_dev.h"
 #include "native_client/src/untrusted/nacl/syscall_bindings_trampoline.h"
 
 static int nacl_irt_close(int fd) {
@@ -64,6 +65,26 @@ static int nacl_irt_getdents(int fd, struct dirent *buf, size_t count,
   return 0;
 }
 
+static int nacl_irt_fchdir(int fd) {
+  return -NACL_SYSCALL(fchdir)(fd);
+}
+
+static int nacl_irt_fchmod(int fd, mode_t mode) {
+  return -NACL_SYSCALL(fchmod)(fd, mode);
+}
+
+static int nacl_irt_fsync(int fd) {
+  return -NACL_SYSCALL(fsync)(fd);
+}
+
+static int nacl_irt_fdatasync(int fd) {
+  return -NACL_SYSCALL(fdatasync)(fd);
+}
+
+static int nacl_irt_ftruncate(int fd, off_t length) {
+  return -NACL_SYSCALL(ftruncate)(fd, length);
+}
+
 const struct nacl_irt_fdio nacl_irt_fdio = {
   nacl_irt_close,
   nacl_irt_dup,
@@ -74,3 +95,19 @@ const struct nacl_irt_fdio nacl_irt_fdio = {
   nacl_irt_fstat,
   nacl_irt_getdents,
 };
+
+const struct nacl_irt_dev_fdio nacl_irt_dev_fdio = {
+  nacl_irt_close,
+  nacl_irt_dup,
+  nacl_irt_dup2,
+  nacl_irt_read,
+  nacl_irt_write,
+  nacl_irt_seek,
+  nacl_irt_fstat,
+  nacl_irt_getdents,
+  nacl_irt_fchdir,
+  nacl_irt_fchmod,
+  nacl_irt_fsync,
+  nacl_irt_fdatasync,
+  nacl_irt_ftruncate,
+};