Handle /dev/null on linux, as an closed device.

runtime/bin/file_linux.cc

Index: runtime/bin/file_linux.cc
diff --git a/runtime/bin/file_linux.cc b/runtime/bin/file_linux.cc
index ce0ef27bb26c5ea84f21e13424b345098c4d2f4e..73b0912053582b12f1217b3a3d505cb6f3fb9857 100644
--- a/runtime/bin/file_linux.cc
+++ b/runtime/bin/file_linux.cc
@@ -107,7 +107,8 @@ File* File::Open(const char* name, FileOpenMode mode) {
   // Report errors for non-regular files.
   struct stat st;
   if (TEMP_FAILURE_RETRY(stat(name, &st)) == 0) {
-    if (!S_ISREG(st.st_mode)) {
+    // Only accept regular files and character devices.
+    if (!S_ISREG(st.st_mode) && !S_ISCHR(st.st_mode)) {
       errno = (S_ISDIR(st.st_mode)) ? EISDIR : ENOENT;
       return NULL;
     }
@@ -122,6 +123,7 @@ File* File::Open(const char* name, FileOpenMode mode) {
   flags |= O_CLOEXEC;
   int fd = TEMP_FAILURE_RETRY(open(name, flags, 0666));
   if (fd < 0) {
+    printf("Open failed\n");

[Søren Gjesse, 2013/03/11 15:08:16]

Debug print.

[Anders Johnsen, 2013/06/11 12:14:41]

Done.

     return NULL;
   }
   if (((mode & kWrite) != 0) && ((mode & kTruncate) == 0)) {