Linux: Add support for chrooted renderers.

base/process_util_linux.cc

 // Copyright (c) 2008 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/process_util.h"
 
 #include <ctype.h>
 #include <dirent.h>
 #include <fcntl.h>
 #include <unistd.h>
@@ skipping 42 matching lines @@
     for (file_handle_mapping_vector::const_iterator
         it = fds_to_remap.begin(); it != fds_to_remap.end(); ++it) {
       fd_shuffle.push_back(InjectionArc(it->first, it->second, false));
     }
 
     if (!ShuffleFileDescriptors(fd_shuffle))
       exit(127);
 
     CloseSuperfluousFds(fd_shuffle);
 
+    // If we are using the SUID sandbox, it sets a magic environment variable
+    // ("SBX_D"), so we remove that variable from the environment here on the
+    // off chance that it's already set.
+    unsetenv("SBX_D");
+
     scoped_array<char*> argv_cstr(new char*[argv.size() + 1]);
     for (size_t i = 0; i < argv.size(); i++)
       argv_cstr[i] = const_cast<char*>(argv[i].c_str());
     argv_cstr[argv.size()] = NULL;
     execvp(argv_cstr[0], argv_cstr.get());
     exit(127);
   } else {
     if (wait)
       HANDLE_EINTR(waitpid(pid, 0, 0));
 
@@ skipping 202 matching lines @@
           (*io_counters).WriteTransferCount = StringToInt64(tokenizer.token());
         }
         state = KEY_NAME;
         break;
     }
   }
   return true;
 }
 
 }  // namespace base