On unix like systems, the underlying file corresponding to any given path may
change at any time. This function makes it possible to set the permissions of
the a file corresponding to a `File` object even if its path changes.
libstd: support creation of anonymous pipe on WinXP/2K3
`PIPE_REJECT_REMOTE_CLIENTS` flag is not supported on Windows < VISTA, and every invocation of `anon_pipe` including attempts to pipe `std::process::Child`'s stdio fails.
This PR should work around this issue by performing a runtime check of windows version and conditionally omitting this flag on "XP and friends".
Getting the version should be probably moved out of the function `anon_pipe` itself (the OS version does not often change during runtime :) ), but:
- I didn't find any precedent for this and assuming there's not much overhead (I hope windows does not perform any heuristics to find out it's own version, just fills couple of fields in the struct).
- the code path is not especially performance sensitive anyway.
The mx_cprng_draw syscall has changed signature to separate the status
and size return values, rather than multiplexing them into a single
value with errors interpreted as a negative value. This patch tracks
that change.
The DirEntryExt::ino() implementation was omitted from the first
iteration of this patch, because a dependency needed to be
configured. The fix is straightforward enough.
It is good practice to implement Debug for public types, and
indicating what directory you're reading seems useful.
Signed-off-by: David Henningsson <diwic@ubuntu.com>
Implement `read_offset` and `write_offset`
These functions allow to read from and write to a file from multiple
threads without changing the per-file cursor, avoiding the race between
the seek and the read.
