to put a regular file in O_NONBLOCK mode fails with EPERM.
That happens on Linux when using tail -f on a file with the
append-only attribute. Reported by Dean Gaudet. For details,
see http://savannah.gnu.org/bugs/?func=detailitem&item_id=15473.
Don't include "lchown.h".
(restricted_chown): Accept a new parameter, CWD_FD, and use it in
calling openat, lchownat, chownat, rather than open, lchown, chown.
Update caller.
its clients accordingly -- note that du.c uses fts but doesn't need
any adjustment, since it doesn't operate on the actual files,
but rather just uses the stat buffers provided by fts.
Include "openat.h".
(process_file): Use chmodat (fts->fts_cwd_fd,... in place of chmod (...
by using openat, fstatat, fdopendir, etc..
[! _LIBC]: Include "openat.h" and "unistd--.h".
(HAVE_OPENAT_SUPPORT): Define.
[_LIBC] (fchdir): Don't undef or define; no longer used.
(FCHDIR): Define in terms of cwd_advance_fd rather than fchdir.
Now, this `function' always succeeds, and consumes its file descriptor
parameter -- so callers must not close such FDs. Update callers.
(diropen_fd, opendirat, cwd_advance_fd): New functions.
(diropen): Add parameter, SP. Adjust all callers.
Implement using diropen_fd, rather than open.
(fts_open): Initialize new member, fts_cwd_fd.
Remove fts_rft-setting code.
(fts_close): Close fts_cwd_fd, if necessary.
(__opendir2): Define in terms of opendir or opendirat,
depending on whether the FST_NOCHDIR flag is set.
(fts_build): Since fts_safe_changedir consumes its FD, and since
this code must do `closedir(dirp)', dup the dirfd(dirp) argument,
and close the dup'd file descriptor upon failure.
(fts_stat): Use fstatat(...AT_SYMLINK_NOFOLLOW) in place of lstat.
(fts_safe_changedir): Tweak semantics to reflect that this function
now calls cwd_advance_fd and hence consumes its FD argument.
