Remove named SharedMemory usage on Mac.

base/memory/shared_memory_mac.cc

 // Copyright (c) 2012 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 "base/memory/shared_memory.h"
 
 #include <fcntl.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ skipping 35 matching lines @@
 
 // Makes a temporary file, fdopens it, and then unlinks it. |fp| is populated
 // with the fdopened FILE. |readonly_fd| is populated with the opened fd if
 // options.share_read_only is true. |path| is populated with the location of
 // the file before it was unlinked.
 // Returns false if there's an unhandled failure.
 bool CreateAnonymousSharedMemory(const SharedMemoryCreateOptions& options,
                                  ScopedFILE* fp,
                                  ScopedFD* readonly_fd,
                                  FilePath* path) {
-  // It doesn't make sense to have a open-existing private piece of shmem
-  DCHECK(!options.open_existing_deprecated);
   // Q: Why not use the shm_open() etc. APIs?
   // A: Because they're limited to 4mb on OS X.  FFFFFFFUUUUUUUUUUU
   FilePath directory;
   ScopedPathUnlinker path_unlinker;
   if (GetShmemTempDir(options.executable, &directory)) {
     // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466437
     // is fixed.
     tracked_objects::ScopedTracker tracking_profile(
         FROM_HERE_WITH_EXPLICIT_FUNCTION(
             "466437 SharedMemory::Create::OpenTemporaryFile"));
-    fp->reset(base::CreateAndOpenTemporaryFileInDir(directory, path));
+    fp->reset(CreateAndOpenTemporaryFileInDir(directory, path));
 
     // Deleting the file prevents anyone else from mapping it in (making it
     // private), and prevents the need for cleanup (once the last fd is
     // closed, it is truly freed).
     if (*fp)
       path_unlinker.reset(path);
   }
 
   if (*fp) {
     if (options.share_read_only) {
       // TODO(erikchen): Remove ScopedTracker below once
       // http://crbug.com/466437 is fixed.
       tracked_objects::ScopedTracker tracking_profile(
           FROM_HERE_WITH_EXPLICIT_FUNCTION(
               "466437 SharedMemory::Create::OpenReadonly"));
       // Also open as readonly so that we can ShareReadOnlyToProcess.
       readonly_fd->reset(HANDLE_EINTR(open(path->value().c_str(), O_RDONLY)));
       if (!readonly_fd->is_valid()) {
         DPLOG(ERROR) << "open(\"" << path->value() << "\", O_RDONLY) failed";
         fp->reset();
         return false;
       }
     }
   }
   return true;
 }
-}
+
+}  // namespace
 
 SharedMemory::SharedMemory()
     : mapped_file_(-1),
       readonly_mapped_file_(-1),
       mapped_size_(0),
       memory_(NULL),
       read_only_(false),
       requested_size_(0) {
 }
 
@@ skipping 37 matching lines @@
 
 // static
 void SharedMemory::CloseHandle(const SharedMemoryHandle& handle) {
   DCHECK_GE(GetFdFromSharedMemoryHandle(handle), 0);
   if (close(GetFdFromSharedMemoryHandle(handle)) < 0)
     DPLOG(ERROR) << "close";
 }
 
 // static
 size_t SharedMemory::GetHandleLimit() {
-  return base::GetMaxFds();
+  return GetMaxFds();
 }
 
 // static
 SharedMemoryHandle SharedMemory::DuplicateHandle(
     const SharedMemoryHandle& handle) {
   return handle.Duplicate();
 }
 
 // static
 int SharedMemory::GetFdFromSharedMemoryHandle(
@@ skipping 31 matching lines @@
 
   if (options.size > static_cast<size_t>(std::numeric_limits<int>::max()))
     return false;
 
   // This function theoretically can block on the disk, but realistically
   // the temporary files we create will just go into the buffer cache
   // and be deleted before they ever make it out to disk.
   base::ThreadRestrictions::ScopedAllowIO allow_io;
 
   ScopedFILE fp;
-  bool fix_size = true;
   ScopedFD readonly_fd;
 
   FilePath path;
-  if (options.name_deprecated == NULL || options.name_deprecated->empty()) {
-    bool result =
-        CreateAnonymousSharedMemory(options, &fp, &readonly_fd, &path);
-    if (!result)
-      return false;
-  } else {
-    if (!FilePathForMemoryName(*options.name_deprecated, &path))
-      return false;
+  bool result = CreateAnonymousSharedMemory(options, &fp, &readonly_fd, &path);
+  if (!result)
+    return false;
 
-    // Make sure that the file is opened without any permission
-    // to other users on the system.
-    const mode_t kOwnerOnly = S_IRUSR | S_IWUSR;
-
-    // First, try to create the file.
-    int fd = HANDLE_EINTR(
-        open(path.value().c_str(), O_RDWR | O_CREAT | O_EXCL, kOwnerOnly));
-    if (fd == -1 && options.open_existing_deprecated) {
-      // If this doesn't work, try and open an existing file in append mode.
-      // Opening an existing file in a world writable directory has two main
-      // security implications:
-      // - Attackers could plant a file under their control, so ownership of
-      //   the file is checked below.
-      // - Attackers could plant a symbolic link so that an unexpected file
-      //   is opened, so O_NOFOLLOW is passed to open().
-      fd = HANDLE_EINTR(
-          open(path.value().c_str(), O_RDWR | O_APPEND | O_NOFOLLOW));
-
-      // Check that the current user owns the file.
-      // If uid != euid, then a more complex permission model is used and this
-      // API is not appropriate.
-      const uid_t real_uid = getuid();
-      const uid_t effective_uid = geteuid();
-      struct stat sb;
-      if (fd >= 0 &&
-          (fstat(fd, &sb) != 0 || sb.st_uid != real_uid ||
-           sb.st_uid != effective_uid)) {
-        LOG(ERROR) <<
-            "Invalid owner when opening existing shared memory file.";
-        close(fd);
-        return false;
-      }
-
-      // An existing file was opened, so its size should not be fixed.
-      fix_size = false;
-    }
-
-    if (options.share_read_only) {
-      // Also open as readonly so that we can ShareReadOnlyToProcess.
-      readonly_fd.reset(HANDLE_EINTR(open(path.value().c_str(), O_RDONLY)));
-      if (!readonly_fd.is_valid()) {
-        DPLOG(ERROR) << "open(\"" << path.value() << "\", O_RDONLY) failed";
-        close(fd);
-        fd = -1;
-        return false;
-      }
-    }
-    if (fd >= 0) {
-      // "a+" is always appropriate: if it's a new file, a+ is similar to w+.
-      fp.reset(fdopen(fd, "a+"));
-    }
-  }
-  if (fp && fix_size) {
-    // Get current size.
-    struct stat stat;
-    if (fstat(fileno(fp.get()), &stat) != 0)
-      return false;
-    const size_t current_size = stat.st_size;
-    if (current_size != options.size) {
-      if (HANDLE_EINTR(ftruncate(fileno(fp.get()), options.size)) != 0)
-        return false;
-    }
-    requested_size_ = options.size;
-  }
-  if (fp == NULL) {
+  if (!fp) {
     PLOG(ERROR) << "Creating shared memory in " << path.value() << " failed";
     return false;
   }
 
+  // Get current size.
+  struct stat stat;
+  if (fstat(fileno(fp.get()), &stat) != 0)
+    return false;
+  const size_t current_size = stat.st_size;
+  if (current_size != options.size) {
+    if (HANDLE_EINTR(ftruncate(fileno(fp.get()), options.size)) != 0)
+      return false;
+  }
+  requested_size_ = options.size;
+
   return PrepareMapFile(fp.Pass(), readonly_fd.Pass());
 }
 
-// Our current implementation of shmem is with mmap()ing of files.
-// These files need to be deleted explicitly.
-// In practice this call is only needed for unit tests.
-bool SharedMemory::Delete(const std::string& name) {
-  FilePath path;
-  if (!FilePathForMemoryName(name, &path))
-    return false;
-
-  if (PathExists(path))
-    return base::DeleteFile(path, false);
-
-  // Doesn't exist, so success.
-  return true;
-}
-
-bool SharedMemory::Open(const std::string& name, bool read_only) {
-  FilePath path;
-  if (!FilePathForMemoryName(name, &path))
-    return false;
-
-  read_only_ = read_only;
-
-  const char *mode = read_only ? "r" : "r+";
-  ScopedFILE fp(base::OpenFile(path, mode));
-  ScopedFD readonly_fd(HANDLE_EINTR(open(path.value().c_str(), O_RDONLY)));
-  if (!readonly_fd.is_valid()) {
-    DPLOG(ERROR) << "open(\"" << path.value() << "\", O_RDONLY) failed";
-    return false;
-  }
-  return PrepareMapFile(fp.Pass(), readonly_fd.Pass());
-}
-
 bool SharedMemory::MapAt(off_t offset, size_t bytes) {
   if (mapped_file_ == -1)
     return false;
 
   if (bytes > static_cast<size_t>(std::numeric_limits<int>::max()))
     return false;
 
   if (memory_)
     return false;
 
   memory_ = mmap(NULL, bytes, PROT_READ | (read_only_ ? 0 : PROT_WRITE),
                  MAP_SHARED, mapped_file_, offset);
 
-  bool mmap_succeeded = memory_ != (void*)-1 && memory_ != NULL;
+  bool mmap_succeeded = memory_ && memory_ != reinterpret_cast<void*>(-1);
   if (mmap_succeeded) {
     mapped_size_ = bytes;
     DCHECK_EQ(0U, reinterpret_cast<uintptr_t>(memory_) &
         (SharedMemory::MAP_MINIMUM_ALIGNMENT - 1));
   } else {
     memory_ = NULL;
   }
 
   return mmap_succeeded;
 }
@@ skipping 70 matching lines @@
                                          FilePath* path) {
   // mem_name will be used for a filename; make sure it doesn't
   // contain anything which will confuse us.
   DCHECK_EQ(std::string::npos, mem_name.find('/'));
   DCHECK_EQ(std::string::npos, mem_name.find('\0'));
 
   FilePath temp_dir;
   if (!GetShmemTempDir(false, &temp_dir))
     return false;
 
-  std::string name_base = std::string(base::mac::BaseBundleID());
+  std::string name_base = std::string(mac::BaseBundleID());
   *path = temp_dir.AppendASCII(name_base + ".shmem." + mem_name);
   return true;
 }
 
 bool SharedMemory::ShareToProcessCommon(ProcessHandle process,
                                         SharedMemoryHandle* new_handle,
                                         bool close_self,
                                         ShareMode share_mode) {
   int handle_to_dup = -1;
-  switch(share_mode) {
+  switch (share_mode) {
     case SHARE_CURRENT_MODE:
       handle_to_dup = mapped_file_;
       break;
     case SHARE_READONLY:
       // We could imagine re-opening the file from /dev/fd, but that can't make
       // it readonly on Mac: https://codereview.chromium.org/27265002/#msg10
       CHECK_GE(readonly_mapped_file_, 0);
       handle_to_dup = readonly_mapped_file_;
       break;
   }
 
   const int new_fd = HANDLE_EINTR(dup(handle_to_dup));
   if (new_fd < 0) {
     DPLOG(ERROR) << "dup() failed.";
     return false;
   }
 
   new_handle->SetFileHandle(new_fd, true);
 
   if (close_self) {
     Unmap();
     Close();
   }
 
   return true;
 }
 
 }  // namespace base