[NaCl SDK] nacl_io: Add umask

The default umask() implemented by libnacl returns 0777, which if actually
used, would create files with 0 mode.

BUG=none
R=sbc@chromium.org

Review URL: https://codereview.chromium.org/643543004

Cr-Commit-Position: refs/heads/master@{#299921}

native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.cc

@@ -324,7 +324,7 @@ Error DevFs::Init(const FsInitArgs& args) {
   if (error)
     return error;
 
-  root_.reset(new DirNode(this));
+  root_.reset(new DirNode(this, S_IRALL | S_IXALL));
 
   ScopedNode new_node;
   INITIALIZE_DEV_NODE("/null", NullNode);
@@ -348,7 +348,7 @@ Error DevFs::Init(const FsInitArgs& args) {
   // Add a directory for "fs" nodes; they represent all currently-mounted
   // filesystems. We can ioctl these nodes to make changes or provide input to
   // a mounted filesystem.
-  INITIALIZE_DEV_NODE("/fs", DirNode);
+  INITIALIZE_DEV_NODE_1("/fs", DirNode, S_IRALL | S_IWALL | S_IXALL);
   fs_dir_ = new_node;
 
   return 0;

native_client_sdk/src/libraries/nacl_io/dir_node.cc

@@ -22,13 +22,12 @@ namespace {
 const ino_t kParentDirIno = -1;
 }
 
-DirNode::DirNode(Filesystem* filesystem)
+DirNode::DirNode(Filesystem* filesystem, mode_t mode)
     : Node(filesystem),
       cache_(stat_.st_ino, kParentDirIno),
       cache_built_(false) {
   SetType(S_IFDIR);
-  // Directories are raadable, writable and executable by default.
-  stat_.st_mode |= S_IRALL | S_IWALL | S_IXALL;
+  SetMode(mode);
 }
 
 DirNode::~DirNode() {

native_client_sdk/src/libraries/nacl_io/dir_node.h

@@ -24,7 +24,7 @@ typedef sdk_util::ScopedRef<DirNode> ScopedDirNode;
 
 class DirNode : public Node {
  protected:
-  explicit DirNode(Filesystem* fs);
+  explicit DirNode(Filesystem* fs, mode_t mode);
   virtual ~DirNode();
 
  public:

native_client_sdk/src/libraries/nacl_io/httpfs/http_fs.cc

@@ -254,12 +254,10 @@ Error HttpFs::FindOrCreateDir(const Path& path, ScopedNode* out_node) {
   }
 
   // If the node does not exist, create it.
-  node.reset(new DirNode(this));
+  node.reset(new DirNode(this, S_IRALL | S_IXALL));
   Error error = node->Init(0);
   if (error)
     return error;
-  // Directorys in http filesystems are never writable.
-  node->SetMode(node->GetMode() & ~S_IWALL);
 
   // If not the root node, find the parent node and add it to the parent
   if (!path.IsRoot()) {

native_client_sdk/src/libraries/nacl_io/kernel_intercept.cc

@@ -427,6 +427,11 @@ int ki_futimens(int fd, const struct timespec times[2]) {
   return s_state.kp->futimens(fd, times);
 }
 
+mode_t ki_umask(mode_t mask) {
+  ON_NOSYS_RETURN(0);
+  return s_state.kp->umask(mask);
+}
+
 int ki_poll(struct pollfd* fds, nfds_t nfds, int timeout) {
   return s_state.kp->poll(fds, nfds, timeout);
 }

native_client_sdk/src/libraries/nacl_io/kernel_intercept.h

@@ -123,6 +123,7 @@ int ki_fchown(int fd, uid_t owner, gid_t group);
 int ki_lchown(const char* path, uid_t owner, gid_t group);
 int ki_utime(const char* filename, const struct utimbuf* times);
 int ki_futimens(int fd, const struct timespec times[2]);
+mode_t ki_umask(mode_t mask);
 
 int ki_poll(struct pollfd* fds, nfds_t nfds, int timeout);
 int ki_select(int nfds,

native_client_sdk/src/libraries/nacl_io/kernel_object.cc

@@ -25,7 +25,7 @@
 
 namespace nacl_io {
 
-KernelObject::KernelObject() {
+KernelObject::KernelObject() : umask_(0) {
   cwd_ = "/";
 }
 
@@ -155,6 +155,17 @@ Error KernelObject::SetCWD(const std::string& path) {
   return 0;
 }
 
+mode_t KernelObject::GetUmask() {
+  return umask_;
+}
+
+mode_t KernelObject::SetUmask(mode_t newmask) {
+  AUTO_LOCK(umask_lock_);
+  mode_t oldmask = umask_;
+  umask_ = newmask & 0777;
+  return oldmask;
+}
+
 Error KernelObject::GetFDFlags(int fd, int* out_flags) {
   AUTO_LOCK(handle_lock_);
   if (fd < 0 || fd >= static_cast<int>(handle_map_.size()))

native_client_sdk/src/libraries/nacl_io/kernel_object.h

@@ -94,11 +94,16 @@ class KernelObject {
   std::string GetCWD();
   Error SetCWD(const std::string& path);
 
+  mode_t GetUmask();
+  // Also returns current umask (like POSIX's umask(2))
+  mode_t SetUmask(mode_t);
+
   // Returns parts of the absolute path for the given relative path
   Path GetAbsParts(const std::string& path);
 
  private:
   std::string cwd_;
+  mode_t umask_;
   std::vector<int> free_fds_;
   HandleMap_t handle_map_;
   FsMap_t filesystems_;
@@ -111,6 +116,8 @@ class KernelObject {
 
   // Lock to protect cwd_.
   sdk_util::SimpleLock cwd_lock_;
+  // Lock to protect umask_.
+  sdk_util::SimpleLock umask_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(KernelObject);
 };

native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc

@@ -209,8 +209,9 @@ int KernelProxy::open_resource(const char* path) {
 int KernelProxy::open(const char* path, int open_flags, mode_t mode) {
   ScopedFilesystem fs;
   ScopedNode node;
+  mode_t mask = ~GetUmask();
 
-  Error error = AcquireFsAndNode(path, open_flags, mode, &fs, &node);
+  Error error = AcquireFsAndNode(path, open_flags, mode & mask, &fs, &node);
   if (error) {
     errno = error;
     return -1;
@@ -371,7 +372,7 @@ int KernelProxy::mkdir(const char* path, mode_t mode) {
     return -1;
   }
 
-  error = fs->Mkdir(rel, mode);
+  error = fs->Mkdir(rel, mode & ~GetUmask());
   if (error) {
     errno = error;
     return -1;
@@ -1182,6 +1183,10 @@ int KernelProxy::sigaction(int signum,
   return -1;
 }
 
+mode_t KernelProxy::umask(mode_t mask) {
+  return SetUmask(mask);
+}
+
 #ifdef PROVIDES_SOCKET_API
 
 int KernelProxy::select(int nfds,

native_client_sdk/src/libraries/nacl_io/kernel_proxy.h

@@ -157,6 +157,7 @@ class KernelProxy : protected KernelObject {
   virtual int sigaction(int signum,
                         const struct sigaction* action,
                         struct sigaction* oaction);
+  virtual mode_t umask(mode_t);
 
 #ifdef PROVIDES_SOCKET_API
   virtual int select(int nfds,

native_client_sdk/src/libraries/nacl_io/library.dsc

@@ -137,6 +137,7 @@
         "syscalls/termios/tcsetattr.c",
         "syscalls/symlink.c",
         "syscalls/truncate.c",
+        "syscalls/umask.c",
         "syscalls/umount.c",
         "syscalls/uname.c",
         "syscalls/utime.c",

native_client_sdk/src/libraries/nacl_io/memfs/mem_fs.cc

@@ -29,7 +29,7 @@ Error MemFs::Init(const FsInitArgs& args) {
   if (error)
     return error;
 
-  root_.reset(new DirNode(this));
+  root_.reset(new DirNode(this, S_IRALL | S_IWALL | S_IXALL));
   error = root_->Init(0);
   if (error) {
     root_.reset(NULL);
@@ -146,7 +146,7 @@ Error MemFs::Mkdir(const Path& path, int mode) {
   // Allocate a node, with a RefCount of 1.  If added to the parent
   // it will get ref counted again.  In either case, release the
   // recount we have on exit.
-  node.reset(new DirNode(this));
+  node.reset(new DirNode(this, mode));
   error = node->Init(0);
   if (error)
     return error;

native_client_sdk/src/libraries/nacl_io/syscalls/umask.c

+/* Copyright (c) 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 "nacl_io/kernel_intercept.h"
+#include "nacl_io/kernel_wrap.h"
+
+mode_t umask(mode_t mask) {
+  return ki_umask(mask);
+}

native_client_sdk/src/tests/nacl_io_test/kernel_proxy_test.cc

@@ -636,6 +636,26 @@ TEST_F(KernelProxyTest, Utime) {
   EXPECT_GE(buf.st_mtimensec, tm.tv_usec * 1000);
 }
 
+TEST_F(KernelProxyTest, Umask) {
+  mode_t oldmask = ki_umask(0222);
+  EXPECT_EQ(0, oldmask);
+
+  int fd = ki_open("/foo", O_CREAT | O_RDONLY, 0666);
+  ASSERT_GT(fd, -1);
+  ki_close(fd);
+
+  EXPECT_EQ(0, ki_mkdir("/dir", 0777));
+
+  struct stat buf;
+  EXPECT_EQ(0, ki_stat("/foo", &buf));
+  EXPECT_EQ(0444, buf.st_mode & ~S_IFMT);
+
+  EXPECT_EQ(0, ki_stat("/dir", &buf));
+  EXPECT_EQ(0555, buf.st_mode & ~S_IFMT);
+
+  EXPECT_EQ(0222, ki_umask(0));
+}
+
 namespace {
 
 StringMap_t g_string_map;

native_client_sdk/src/tests/nacl_io_test/mem_fs_node_test.cc

@@ -62,7 +62,9 @@ class MemFsNodeForTesting : public MemFsNode {
 
 class DirNodeForTesting : public DirNode {
  public:
-  DirNodeForTesting() : DirNode(NULL) { s_alloc_num++; }
+  DirNodeForTesting() : DirNode(NULL, S_IRALL | S_IWALL | S_IXALL) {
+    s_alloc_num++;
+  }
 
   ~DirNodeForTesting() { s_alloc_num--; }