Implement nacl_irt_fdio for non-sfi mode.

components/nacl/loader/nonsfi/irt_fdio.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "base/logging.h"
+#include "components/nacl/loader/nonsfi/irt_interfaces.h"
+#include "native_client/src/trusted/service_runtime/include/sys/dirent.h"
+#include "native_client/src/trusted/service_runtime/include/sys/stat.h"
+#include "native_client/src/trusted/service_runtime/include/sys/unistd.h"
+
+namespace nacl {
+namespace nonsfi {
+namespace {
+
+int IrtClose(int fd) {
+  if (::close(fd) < 0)
+    return errno;
+  return 0;
+}
+
+int IrtDup(int fd, int* newfd) {
+  int result = ::dup(fd);
+  if (result < 0)
+    return errno;
+
+  *newfd = result;
+  return 0;
+}
+
+int IrtDup2(int fd, int newfd) {
+  if (::dup2(fd, newfd) < 0)
+    return errno;
+  return 0;
+}
+
+int IrtRead(int fd, void* buf, size_t count, size_t* nread) {
+  ssize_t result = ::read(fd, buf, count);
+  if (result < 0)
+    return errno;
+
+  *nread =result;
+  return 0;
+}
+
+int IrtWrite(int fd, const void* buf, size_t count, size_t* nwrote) {
+  ssize_t result = ::write(fd, buf, count);
+  if (result < 0)
+    return errno;
+
+  *nwrote = result;
+  return 0;
+}
+
+int IrtSeek(int fd, nacl_abi_off_t offset, int whence,
+            nacl_abi_off_t* new_offset) {
+  off_t result = ::lseek(fd, offset, whence);

[hamaji, 2014/01/09 10:47:22]

Same as fstat. Probably better to check if this call is referring lseek64.

[hidehiko, 2014/01/09 12:41:19]

Yes, I've checked. common.gypi defines _FILE_OFFSET_BITS=64.

+  if (result < 0)
+    return errno;
+  *new_offset = result;
+  return 0;
+}
+
+int IrtFstat(int fd, struct nacl_abi_stat* st) {
+  struct stat host_st;
+  if (::fstat(fd, &host_st) < 0)

[hamaji, 2014/01/09 10:47:22]

As locally chatted, I think we need to call fstat64 here. Have you checked
irt_fdio.o has a reference to fstat64 (__fxstat64 maybe)? If you've already
checked this, how about adding this in the TEST line?

[hidehiko, 2014/01/09 12:41:19]

Done.

+    return errno;
+
+  memset(st, 0, sizeof(*st));
+  st->nacl_abi_st_dev = 0;

[hamaji, 2014/01/09 10:47:22]

You'll need to use this code when you implement IrtStat. How about creating a
function which converts from glibc stat to NaCl stat?

[hidehiko, 2014/01/09 12:41:19]

Yes, I was planning to do it in a following CL (w/ irt_filename implementatino),
but doing it in this CL is fine to me. Done.

+  st->nacl_abi_st_ino = host_st.st_ino;
+  nacl_abi_mode_t m;
+  switch (host_st.st_mode & S_IFMT) {
+    case S_IFREG:
+      m = NACL_ABI_S_IFREG;
+      break;
+    case S_IFDIR:
+      m = NACL_ABI_S_IFDIR;
+      break;
+    case S_IFCHR:
+      m = NACL_ABI_S_IFCHR;
+      break;

[hamaji, 2014/01/09 10:47:22]

I'm not sure, but I'd translate all possible values. It should be useful for
unittests based on sel_ldr (or nonsfi_ldr?).

[hidehiko, 2014/01/09 12:41:19]

I just mimic'ed the NaCl's original implementation, and IMHO keeping it sync'ed
is valuable. Ditto for missing bits/fields below. WDYT?

+    default:
+      LOG(ERROR) << "Unusual NaCl descriptor type.";

[hamaji, 2014/01/09 10:47:22]

LOG(ERROR) might be over kill? And, how about outputting st_mode & S_IFMT?

[hidehiko, 2014/01/09 12:41:19]

Done. Redcued to LOG(WARNING).

+      m = NACL_ABI_S_UNSUP;
+  }
+  if (host_st.st_mode & S_IRUSR)
+    m |= NACL_ABI_S_IRUSR;
+  if (host_st.st_mode & S_IWUSR)
+    m |= NACL_ABI_S_IWUSR;
+  if (host_st.st_mode & S_IXUSR)
+    m |= NACL_ABI_S_IXUSR;

[hamaji, 2014/01/09 10:47:22]

Is it intentional we are dropping S_I*GRP and S_I*OTH ? If so, it would be
better to have a comment here.

[hidehiko, 2014/01/09 12:41:19]

Acknowledged.

+  st->nacl_abi_st_mode = m;
+  st->nacl_abi_st_nlink = host_st.st_nlink;
+  st->nacl_abi_st_uid = -1;  // Not root
+  st->nacl_abi_st_gid = -1;  // Not wheel
+  st->nacl_abi_st_rdev = 0;
+  st->nacl_abi_st_size = host_st.st_size;
+  st->nacl_abi_st_blksize = 0;
+  st->nacl_abi_st_blocks = 0;
+  st->nacl_abi_st_atime = host_st.st_atime;
+  st->nacl_abi_st_mtime = host_st.st_mtime;
+  st->nacl_abi_st_ctime = host_st.st_ctime;

[hamaji, 2014/01/09 10:47:22]

Any reason we don't copy nano seconds? For compatibility maybe? Would be better
to have a comment?

[hidehiko, 2014/01/09 12:41:19]

Acknowledged.

+
+  return 0;
+}
+
+int IrtGetDents(int fd, struct nacl_abi_dirent* buf, size_t count,
+                size_t* nread) {
+  // Note: getdents() can return several directory entries in packed format.
+  // So, here, because we need to convert the abi from host's to nacl's,
+  // there is no straightforward way to ensure reading only entries which can
+  // be fit to the buf after abi conversion actually.

[hamaji, 2014/01/09 10:47:22]

TODO maybe?

[hidehiko, 2014/01/09 12:41:19]

Done.

+  return ENOSYS;
+}
+
+}  // namespace
+
+// for seek, fstat and getdents, their argument types should be nacl_abi_X,
+// rather than host type, such as off_t, struct stat or struct dirent.
+// However, the definition of nacl_irt_fdio uses host types, so here we need
+// to cast them.
+const nacl_irt_fdio kIrtFdIO = {
+  IrtClose,
+  IrtDup,
+  IrtDup2,
+  IrtRead,
+  IrtWrite,
+  reinterpret_cast<int(*)(int, off_t, int, off_t*)>(IrtSeek),
+  reinterpret_cast<int(*)(int, struct stat*)>(IrtFstat),
+  reinterpret_cast<int(*)(int, struct dirent*, size_t, size_t*)>(IrtGetDents),
+};
+
+}  // namespace nonsfi
+}  // namespace nacl