Add _android files for building DartVM on Android

runtime/bin/directory_android.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 "bin/directory.h"
 
 #include <dirent.h>
 #include <errno.h>
 #include <sys/param.h>
 #include <sys/stat.h>
@@ skipping 358 matching lines @@
     ASSERT(errno == ELOOP ||
            errno == ENAMETOOLONG ||
            errno == ENOENT ||
            errno == ENOTDIR);
     return DOES_NOT_EXIST;
   }
 }
 
 
 char* Directory::Current() {
-  return getcwd(NULL, 0);
+  // Android's getcwd adheres closely to the POSIX standard. It won't
+  // allocate memory. We need to make our own copy.
+
+  char buffer[PATH_MAX];
+  if (NULL == getcwd(buffer, PATH_MAX)) {
+    return NULL;
+  }
+
+  return strdup(buffer);
 }
 
 
 bool Directory::Create(const char* dir_name) {
   // Create the directory with the permissions specified by the
   // process umask.
   return (TEMP_FAILURE_RETRY(mkdir(dir_name, 0777)) == 0);
 }
 
 
+// Android doesn't currently provide mkdtemp.  Once Android provied mkdtemp,
+// remove this function in favor of calling mkdtemp directly.
+static char* MakeTempDirectory(char* path_template) {
+  if (mktemp(path_template) == NULL) {
+    return NULL;
+  }
+  if (mkdir(path_template, 0700) != 0) {
+    return NULL;
+  }
+  return path_template;
+}
+
+
 char* Directory::CreateTemp(const char* const_template) {
   // Returns a new, unused directory name, modifying the contents of
   // dir_template.  Creates the directory with the permissions specified
   // by the process umask.
   // The return value must be freed by the caller.
   char* path = static_cast<char*>(malloc(PATH_MAX + 1));
   SafeStrNCpy(path, const_template, PATH_MAX + 1);
   int path_length = strlen(path);
   if (path_length > 0) {
     if ((path)[path_length - 1] == '/') {
       snprintf(path + path_length, PATH_MAX - path_length, "temp_dir_XXXXXX");
     } else {
       snprintf(path + path_length, PATH_MAX - path_length, "XXXXXX");
     }
   } else {
-    snprintf(path, PATH_MAX, "/tmp/temp_dir1_XXXXXX");
+    // Android does not have a /tmp directory. A partial substitute,
+    // suitable for bring-up work and tests, is to create a tmp
+    // directory in /data/local/tmp.
+    //
+    // TODO(4413): In the long run, when running in an application we should
+    // probably use android.content.Context.getCacheDir().
+    #define ANDROID_TEMP_DIR "/data/local/tmp"
+    struct stat st;
+    if (stat(ANDROID_TEMP_DIR, &st) != 0) {
+      mkdir(ANDROID_TEMP_DIR, 0777);
+    }
+    snprintf(path, PATH_MAX, ANDROID_TEMP_DIR "/temp_dir1_XXXXXX");
   }
   char* result;
   do {
-    result = mkdtemp(path);
+    result = MakeTempDirectory(path);
   } while (result == NULL && errno == EINTR);
   if (result == NULL) {
     free(path);
     return NULL;
   }
   return path;
 }
 
 
 bool Directory::Delete(const char* dir_name, bool recursive) {
   if (!recursive) {
     return (TEMP_FAILURE_RETRY(remove(dir_name)) == 0);
   } else {
     return DeleteRecursively(dir_name);
   }
 }
 
 
 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);
 }