[PATCH] libc++: Add option to disable access to the global filesystem namespace

[Ed Schouten]

Hi jroelofs,

Systems like FreeBSD's Capsicum and Nuxi CloudABI apply the concept of capability-based security on the way processes can interact with the filesystem API. It is no longer to interact with the VFS through calls like open(), unlink(), rename(), etc. Instead, processes are only allowed to interact with files and directories to which they have been granted access. The *at() functions can be used for this purpose.

This change adds a new config switch called _LIBCPP_HAS_GLOBAL_FILESYSTEM_NAMESPACE. If not set, all functionality that requires the global filesystem namespace will be disabled. More concretely:

- fstream's open() function will be removed.
- cstdio will no longer pull in fopen(), rename(), etc.
- The test suite's get_temp_file_name() will be removed. This will cause all tests that use the global filesystem namespace to break, but will at least make all the other tests run (as get_temp_file_name will not build anyway).

It is important to mention that this change will make fstream rather useless on those systems for now. Still, I'd rather not have fstream disabled entirely, as it is of course possible to come up with an extension for fstream that would allow access to local filesystem namespaces (e.g., by adding an openat() member function).

REPOSITORY
  rL LLVM

http://reviews.llvm.org/D8194

Files:
  include/__config
  include/cstdio
  include/fstream
  test/support/platform_support.h

EMAIL PREFERENCES
  http://reviews.llvm.org/settings/panel/emailpreferences/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D8194.21560.patch
Type: text/x-patch
Size: 6787 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20150310/c9f0c878/attachment.bin>