Hi Ben,
On Jan 20 17:10, Ben Wijen wrote:
> Implement wincap.has_posix_unlink_semantics_with_ignore_readonly and when set
> skip setting/clearing of READONLY attribute and instead use
> FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE
> ---
> winsup/cygwin/ntdll.h | 3 ++-
> winsup/cygwin/syscalls.cc | 14 +++++-----
> winsup/cygwin/wincap.cc | 11 ++++++++
> winsup/cygwin/wincap.h | 56 ++++++++++++++++++++-------------------
> 4 files changed, 49 insertions(+), 35 deletions(-)
>
> diff --git a/winsup/cygwin/ntdll.h b/winsup/cygwin/ntdll.h
> index d4f6aaf45..7eee383dd 100644
> --- a/winsup/cygwin/ntdll.h
> +++ b/winsup/cygwin/ntdll.h
> @@ -497,7 +497,8 @@ enum {
> FILE_DISPOSITION_DELETE = 0x01,
> FILE_DISPOSITION_POSIX_SEMANTICS = 0x02,
> FILE_DISPOSITION_FORCE_IMAGE_SECTION_CHECK = 0x04,
> - FILE_DISPOSITION_ON_CLOSE = 0x08
> + FILE_DISPOSITION_ON_CLOSE = 0x08,
> + FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE = 0x10,
> };
>
> enum
> diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc
> index 4742c6653..2e50ad7d5 100644
> --- a/winsup/cygwin/syscalls.cc
> +++ b/winsup/cygwin/syscalls.cc
> @@ -709,14 +709,11 @@ _unlink_nt (path_conv &pc, bool shareable)
> flags);
A few lines above, FILE_WRITE_ATTRIBUTES is added to the
access mask, if the file is R/O. This, too, depends on
wincap.has_posix_unlink_semantics_with_ignore_readonly().
> if (!NT_SUCCESS (status))
> goto out;
> - /* Why didn't the devs add a FILE_DELETE_IGNORE_READONLY_ATTRIBUTE
> - flag just like they did with FILE_LINK_IGNORE_READONLY_ATTRIBUTE
> - and FILE_LINK_IGNORE_READONLY_ATTRIBUTE???
> -
> - POSIX unlink semantics are nice, but they still fail if the file
> + /* POSIX unlink semantics are nice, but they still fail if the file
> has the R/O attribute set. Removing the file is very much a safe
> bet afterwards, so, no transaction. */
This comment should contain a short comment "W10 1809+, blah blah",
analogue to the comment in line 698 in terms of 1709+ ("++"? Oops,
fix typo...).
> - if (pc.file_attributes () & FILE_ATTRIBUTE_READONLY)
> + if (!wincap.has_posix_unlink_semantics_with_ignore_readonly ()
> + && (pc.file_attributes () & FILE_ATTRIBUTE_READONLY))
I'd invert the test order here. On 1809+ systems, the majority of
systems these days, the first test is always true, but it's always
checked, even if the file is not R/O. First checking for R/O would
reduce the hits on the "with_ignore_readonly" check.
> {
> status = NtSetAttributesFile (fh, pc.file_attributes ()
> & ~FILE_ATTRIBUTE_READONLY);
> @@ -727,10 +724,13 @@ _unlink_nt (path_conv &pc, bool shareable)
> }
> }
> fdie.Flags = FILE_DISPOSITION_DELETE |
> FILE_DISPOSITION_POSIX_SEMANTICS;
> + if(wincap.has_posix_unlink_semantics_with_ignore_readonly ())
^^^
space
> + fdie.Flags |= FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE;
^^^^
indentation 2, not 4.
> status = NtSetInformationFile (fh, &io, &fdie, sizeof fdie,
> FileDispositionInformationEx);
> /* Restore R/O attribute in case we have multiple hardlinks. */
> - if (pc.file_attributes () & FILE_ATTRIBUTE_READONLY)
> + if (!wincap.has_posix_unlink_semantics_with_ignore_readonly ()
> + && (pc.file_attributes () & FILE_ATTRIBUTE_READONLY))
Same here.
Actually, on second thought, what about introducing another bool at the
start of the posix handling, along the lines of
const bool needs_ro_handling =
(pc.file_attributes () & FILE_ATTRIBUTE_READONLY)
&& !wincap.has_posix_unlink_semantics_with_ignore_readonly ();
and then check for needs_ro_handling throughout?
Thanks,
Corinna
