First cut of a signalfd implementation.
Still TODO: Non-polling select.
This should mostly work as on Linux except for missing support
for some members of struct signalfd_siginfo, namely ssi_fd,
ssi_band (both SIGIO/SIGPOLL, not fully implemented) and ssi_trapno
(HW exception, required HW support).
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
There's a long-standing bug in select. If we have poll-only
descriptors in the fd set, select overwrites the incoming
fd sets with the polling result. If none of the fds is ready,
select has to loop again. But now the fd sets are set to all
zero and select hangs.
Fix this by utilizing the local fd sets r, w, e as storage for
the incoming fd sets and use them to initialize select_stuff.
If we have to loop, overwritung the incoming fd sets doesn't matter.
While at it, rename r, w, e to readfds_in, writefds_in, exceptfds_in.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- use int64_t instead of long long
- make is_timer_tracker const
- improve copyright header comment
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
So far we check the recycler name all the time, and the last interation
also only managed to handle two ways to write the recycler. However,
an adventurous user might change the case of the recycler arbitrarily.
Fix this problem by keeping track of the name in a somewhat relaxed
fashion. Use camel back on drive C by default, all upper case elsewhere.
Only if the rename op fails do we fix the recycler name on the fly
when trying to create it, and it turns out it already existed.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
If the first rename fails, we reopen the rootdir for creating a subdir.
The rootdir handle can change its value at this point, but the code
doesn't take this into account. The subsequent rename then fails with
STATUS_INVALID_HANDLE. Fix this by copying the new rootdir value to
pfri->RootDirectory.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
So far we reopened the file if it was opened case sensitive to
workaround the problem that the recycler could be named in
camel back or all upper case, depending on who created it.
That's a problem for O_TMPFILE on pre-W10. As soon as the
original HANDLE gets closed, delete-on-close is converted to full
delete disposition and all useful operations on the file cease to
work (STATUS_ACCESS_DENIED or STATUS_FILE_DELETED).
To avoid that problem drop the reopen code and check for the exact
recycler filename, either $Recycle.Bin or $RECYCLE.BIN, if the file
has been opened case sensitive.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
On pre-W10 systems there's no way to reopen a file by handle if
the delete disposition is set. We try to get around with
duplicating the handle.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The new proc fd code accidentally allowed to linkat an O_TMPFILE
even if the file has been opened with O_EXCL. This patch fixes it.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
move special fd symlink code into own fhandler_process_fd class
to simplify further additions to /proc/PID/fd/DESCRIPTOR symlink
handling.
Add a method to handle stat(2) on such a proc fd symlink by handle.
This allows correct reply from stat(2) if the target file has been
deleted. This eventually fixes `awk -f /dev/fd/3 3<<eof'.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
path_conv now sets the PATH_RESOLVE_PROCFD flag in path_flags if
the PC_SYM_NOFOLLOW_PROCFD pathconv_arg flag has been set on input
*and* the file is actually a proc fd symlink.
Add matching path_conv::follow_fd_symlink method for checking and
use it in open(2).
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- Remove another unfortunate amalgamation: Mount flags (MOUNT_xxx)
are converted to path_types (PATH_xxx) and mixed with non-mount
path_types flags in the same storage, leading to a tangled,
pell-mell usage of mount flags and path flags in path_conv and
symlink_info.
- There's also the case of PC_NONULLEMPTY. It's used in exactly
one place with a path_conv constructor only used in this single
place, just to override the automatic PC_NULLEMPTY addition
when calling the other path_conv constructors. Crazily,
PC_NONULLEMPTY is a define, no path_types flag, despite its
name.
- It doesn't help that the binary flag exists as mount and path
flag, while the text flag only exists as path flag. This leads
to mount code using path flags to set text/binary. Very confusing
is the fact that a text mount/path flag is not actually required;
the mount code sets the text flag on non binary mounts anyway, so
there are only two states. However, to puzzle people a bit more,
path_conv::binary wrongly implies there's a third, non-binary/non-text
state.
Clean up this mess:
- Store path flags separately from mount flags in path_conv and
symlink_info classes and change all checks and testing inline
methods accordingly.
- Make PC_NONULLEMPTY a simple path_types flag and drop the
redundant path_check constructor.
- Clean up the definition of pathconv_arg, path_types, and mount flags.
Use _BIT expression, newly define in cygwin/bits.h.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
There's an unfortunate amalgamation of caller-provided pathconv_arg
flags with path_types flags which in turn are mostly mount flags.
This leads to a confusion of flag values in sylink_info::pflags and,
in turn, in path_conv::path_flags.
This patch decouples pathconv_flags from the other flags by making
sure that a pathconv_flag is never copied into a variable used for
path_types flags. Also, remove PATH_NO_ACCESS_CHECK since it's
not necessary.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Along the same lines as the previous patch: By reopening an
O_TMPFILE by handle, we can now move the file to the bin at
open time and thus free'ing up the parent dir and *still*
open the file as /proc/PID/fd/DESCRIPTOR by linkat(2).
Allows expressions along the lines of `cat /proc/self/fd/0 <<EOF'.
The problem here is that the temporary file used for the here script
has already been deleted by the shell. Opening by filename, as
implemented so far, doesn't work because the file has been moved
to the bin.
Allow reopening files by handle the same way from another process
as long as we have sufficient permissions on the foreign process.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
To allow reopening a file open in another process by HANDLE, introduce
a matching file_pathconv method, taking a file descriptor as parameter.
The result is a serialized path_conv and a HANDLE value. The HANDLE is
valid in the foreign process and MUST be duplicated into the target
process before usage.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
So far io_handle is NULL when calling fhandler_base::open to
open or create a file. Add a check for io_handle to allow
priming the fhandler with a HANDLE value so we can reopen a
file from a HANDLE on file systems supporting it. This allows
to open already deleted files for further action. This will
be used by open("/proc/PID/fd/DESCRIPTOR") scenarios.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The commit message of commit 07e0a9584f
and the expectation set therein, are wrong.
There's no POSIX semantics allowing to link a file with a link
count of 0 and making it available in the file system again.
In fact, the Linux linkat extension AT_EMPTY_PATH explicitely
disallows to link a file descriptor to a file with a link count
of 0, except for O_TMPFILE without O_EXCL.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This patch significantly improves performance of memmem using a novel
modified Horspool algorithm. Needles up to size 256 use a bad-character
table indexed by hashed pairs of characters to quickly skip past mismatches.
Long needles use a self-adapting filtering step to avoid comparing the whole
needle repeatedly.
By limiting the needle length to 256, the shift table only requires 8 bits
per entry, lowering preprocessing overhead and minimizing cache effects.
This limit also implies worst-case performance is linear.
Small needles up to size 2 use a dedicated linear search. Very long needles
use the Two-Way algorithm (to avoid increasing stack size inlining is now disabled).
The performance gain is 6.6 times on English text on AArch64 using random
needles with average size 8 (this is even faster than the recently improved strstr
algorithm, so I'll update that in the near future).
The size-optimized memmem has also been rewritten from scratch to get a
2.7x performance gain.
Tested against GLIBC testsuite and randomized tests.
Message-Id: <DB5PR08MB1030649D051FA8532A4512C883B20@DB5PR08MB1030.eurprd08.prod.outlook.com>
- Turns out, the definition of POSIX unlink semantics is half-hearted
so far: It's not possible to link an open file HANDLE if it has
been deleted with POSIX semantics, nor is it possible to remove
the delete disposition. This breaks linkat on an O_TMPFILE.
Tested with W10 1809.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Corinna Vinschen
Ken Brown
Wilco Dijkstra
Jeff Johnston