AppendToFile implementation.

base/file_util_posix.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/file_util.h"
 
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <fnmatch.h>
@@ skipping 646 matching lines @@
     bytes_written_partial =
         HANDLE_EINTR(write(fd, data + bytes_written_total,
                            size - bytes_written_total));
     if (bytes_written_partial < 0)
       return -1;
   }
 
   return bytes_written_total;
 }
 
+int AppendToFile(const FilePath& filename, const char* data, int size) {
+  base::ThreadRestrictions::AssertIOAllowed();
+  int fd = HANDLE_EINTR(open(filename.value().c_str(), O_WRONLY | O_APPEND));
+  if (fd < 0)
+    return -1;
+
+  int bytes_written = WriteFileDescriptor(fd, data, size);
+  if (int ret = HANDLE_EINTR(close(fd)) < 0)
+    return ret;
+  return bytes_written;
+}
+
 // Gets the current working directory for the process.
 bool GetCurrentDirectory(FilePath* dir) {
   // getcwd can return ENOENT, which implies it checks against the disk.
   base::ThreadRestrictions::AssertIOAllowed();
 
   char system_buffer[PATH_MAX] = "";
   if (!getcwd(system_buffer, sizeof(system_buffer))) {
     NOTREACHED();
     return false;
   }
@@ skipping 425 matching lines @@
 
     allowed_group_ids.insert(group_record->gr_gid);
   }
 
   return VerifyPathControlledByUser(
       kFileSystemRoot, path, kRootUid, allowed_group_ids);
 }
 #endif  // defined(OS_MACOSX)
 
 }  // namespace file_util