Provide a POSIX-compliant implementation of Directory::Current.

runtime/bin/directory_linux.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_LINUX)
 
 #include "bin/directory.h"
 
 #include <dirent.h>  // NOLINT
@@ skipping 398 matching lines @@
     ASSERT(errno == ELOOP ||
            errno == ENAMETOOLONG ||
            errno == ENOENT ||
            errno == ENOTDIR);
     return DOES_NOT_EXIST;
   }
 }
 
 
 char* Directory::Current() {
-  return getcwd(NULL, 0);
+  size_t size = PATH_MAX;
+  char* buffer = NULL;
+  for (char* result = NULL; result == NULL; size *= 2) {
+    if ((buffer = reinterpret_cast<char*>(realloc(buffer, size))) == NULL) {
+      return NULL;
+    }
+    result = getcwd(buffer, size);
+    if (result == NULL && errno != ERANGE) {
+      return NULL;
+    }
+  }
+  return buffer;
 }
 
 
 bool Directory::SetCurrent(const char* path) {
   int result = TEMP_FAILURE_RETRY(chdir(path));
   return result == 0;
 }
 
 
 bool Directory::Create(const char* dir_name) {
@@ skipping 59 matching lines @@
 bool Directory::Rename(const char* path, const char* new_path) {
   ExistsResult exists = Exists(path);
   if (exists != EXISTS) return false;
   return (TEMP_FAILURE_RETRY(rename(path, new_path)) == 0);
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)