Add crash keys about field trial shared memory errors.

base/memory/shared_memory_helper.cc

 // Copyright 2016 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_helper.h"
 
 #include "base/threading/thread_restrictions.h"
 
 namespace base {
 
 struct ScopedPathUnlinkerTraits {
   static const FilePath* InvalidValue() { return nullptr; }
 
   static void Free(const FilePath* path) {
     if (unlink(path->value().c_str()))
       PLOG(WARNING) << "unlink";
   }
 };
 
 // Unlinks the FilePath when the object is destroyed.
 using ScopedPathUnlinker =
     ScopedGeneric<const FilePath*, ScopedPathUnlinkerTraits>;
 
 #if !defined(OS_ANDROID)
 bool CreateAnonymousSharedMemory(const SharedMemoryCreateOptions& options,
                                  ScopedFILE* fp,
                                  ScopedFD* readonly_fd,
-                                 FilePath* path) {
+                                 FilePath* path,
+                                 SharedMemoryError* error) {
 #if !(defined(OS_MACOSX) && !defined(OS_IOS))
   // It doesn't make sense to have a open-existing private piece of shmem
   DCHECK(!options.open_existing_deprecated);
 #endif  // !(defined(OS_MACOSX) && !defined(OS_IOS)
   // 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))
+  if (!GetShmemTempDir(options.executable, &directory)) {
+    *error = SharedMemoryError::NO_TEMP_DIR;
     return false;
+  }
 
   fp->reset(base::CreateAndOpenTemporaryFileInDir(directory, path));
-
-  if (!*fp)
+  if (!*fp) {
+    *error = SharedMemoryError::NO_FILE;
     return false;
+  }
 
   // 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).
   path_unlinker.reset(path);
 
   if (options.share_read_only) {
     // Also open as readonly so that we can GetReadOnlyHandle.
     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();
+      *error = SharedMemoryError::MAKE_READONLY_FAILED;
       return false;
     }
   }
   return true;
 }
 
-bool PrepareMapFile(ScopedFILE fp, ScopedFD readonly_fd, int* mapped_file,
-                    int* readonly_mapped_file) {
+bool PrepareMapFile(ScopedFILE fp,
+                    ScopedFD readonly_fd,
+                    int* mapped_file,
+                    int* readonly_mapped_file,
+                    SharedMemoryError* error) {
   DCHECK_EQ(-1, *mapped_file);
   DCHECK_EQ(-1, *readonly_mapped_file);
-  if (fp == NULL)
+  if (!fp) {
+    *error = SharedMemoryError::NO_FILE;
     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;
 
   if (readonly_fd.is_valid()) {
     struct stat st = {};
     if (fstat(fileno(fp.get()), &st))
       NOTREACHED();
 
     struct stat readonly_st = {};
     if (fstat(readonly_fd.get(), &readonly_st))
       NOTREACHED();
     if (st.st_dev != readonly_st.st_dev || st.st_ino != readonly_st.st_ino) {
       LOG(ERROR) << "writable and read-only inodes don't match; bailing";
+      *error = SharedMemoryError::INODE_MISMATCH;
       return false;
     }
   }
 
   *mapped_file = HANDLE_EINTR(dup(fileno(fp.get())));
   if (*mapped_file == -1) {
     NOTREACHED() << "Call to dup failed, errno=" << errno;
   }
   *readonly_mapped_file = readonly_fd.release();
 
   return true;
 }
 #endif  // !defined(OS_ANDROID)
 
 }  // namespace base