Ken Brown [Thu, 28 May 2020 17:05:32 +0000 (13:05 -0400)]
Cygwin: stat: fix st_mode of fifos again
This partially reverts commit f36262d56ac78f04de147746ce4a85c6155e4a23. That commit incorrectly
made the st_mode of a fifo reflect the Windows permissions of the disk
file underlying the fifo.
Corinna Vinschen [Mon, 25 May 2020 15:40:27 +0000 (17:40 +0200)]
Cygwin: revamp localtime.o build rule
Rename localtime.c.patched to localtime.patched.c to keep the correct
language suffix.
Create localtime.patched.c in the build dir rather than in the source
dir. Decouple the build rule for creating localtime.patched.c from
the rule to build localtime.o, so we don't have to rebuild the patched
source file all the time.
Mark Geisert [Fri, 22 May 2020 09:32:53 +0000 (02:32 -0700)]
Cygwin: tzcode resync: details
Add tz_posixrules.h with data generated from most recent Cygwin tzdata
package. Establish localtime.cc as primarily a wrapper around a patched
copy of localtime.c. See README for more information.
Mark Geisert [Fri, 22 May 2020 09:32:51 +0000 (02:32 -0700)]
Cygwin: tzcode resync: basics
Modifies winsup/cygwin/Makefile.in to build localtime.o from items in
new winsup/cygwin/tzcode subdirectory. Compiler option "-fpermissive"
is used to accept warnings about missing casts on the return values of
malloc() calls. This patch also removes existing localtime.cc and
tz_posixrules.h from winsup/cygwin as they are superseded by the
subsequent patches in this set.
Cygwin: pty: Stop counting number of slaves attached to pseudo console.
- The number of slaves attached to pseudo console is used only for
triggering redraw screen. Counting was not only needless, but also
did not work as expected. This patch removes the code for counting.
Cygwin: pty: Revise code to make system_printf() work after close.
- After commit 0365031ce1347600d854a23f30f1355745a1765c, the issue
https://cygwin.com/pipermail/cygwin-patches/2020q2/010259.html
occurs. This patch fixes the issue.
There is no need to explicitly take ownership in fixup_after_exec; if
ownership transfer is needed, it will be taken care of by
fhandler_fifo::close when the parent closes. Moreover, closing the
parent's fifo_reader_thread can cause problems, such as the one
reported here:
Cygwin: pty: Call FreeConsole() only if attached to current pty.
- After commit 071b8e0cbd4be33449c12bb0d58f514ed8ef893c, the problem
reported in https://cygwin.com/pipermail/cygwin/2020-May/244873.html
occurs. This is due to freeing console device accidentally rather
than pseudo console. This patch makes sure to call FreeConsole()
only if the process is attached to the pseudo console of the current
pty.
Szabolcs Nagy [Tue, 19 May 2020 09:52:49 +0000 (10:52 +0100)]
Reimplement aligned_alloc
The original implementation had multiple issues:
- Only worked when posix_memalign was available (Linux, RTEMS).
- Violated C11 link namespace rules by calling posix_memalign.
- Failed to set errno on error.
These can be fixed by essentially using the same implementation
for aligned_alloc as for memalign, i.e. simply calling _memalign_r
(which is always available and a "more reserved name" although
technically still not in the reserved link namespace, at least
code written in c cannot define a colliding symbol, newlib has
plenty such namespace issues so this is fine).
It is not clear what the right policy is when MALLOC_PROVIDED is set,
currently that does not cover aligned_alloc so it is kept that way.
Windows Explorer shows a warning with Cygwin-created DACLs, but putting
the text of the warning into Google doesn't lead to the relevant Cygwin
docs. Let's copy the warning text into the docs in the hopes of helping
confused users. Most of the credit for the wording belongs to Yaakov
Selkowitz.
Ken Brown [Mon, 11 May 2020 13:03:37 +0000 (09:03 -0400)]
Cygwin: FIFO: improve the interruptibility of raw_read
During a blocking read, we sleep for 1 ms after each iteration through
the connected writers. Currently we do this by calling Sleep (1).
Remove this call to Sleep and instead change the timeout in the
cygwait call from 0 to 1, so that raw_read can be interrupted while
sleeping.
Ken Brown [Sat, 9 May 2020 21:25:39 +0000 (17:25 -0400)]
Cygwin: FIFO: code simplification
There are currently three functions that call NtQueryInformationFile
to determine the state of a pipe instance. Do this only once, in a
new fifo_client_handler::set_state () function, and call that when
state information is needed.
Remove the fifo_client_handler methods pipe_state and get_state, which
are no longer needed.
Make fhandler_fifo::get_fc_handler return a reference, for use in
select.cc:peek_fifo.
Make other small changes to ensure that this commit doesn't change any
decisions based on the state of a fifo_client_handler.
The tricky part is interpreting FILE_PIPE_CLOSING_STATE, which we
translate to fc_closing. Our current interpretation, which is not
changing as a result of this commit, is that the writer at the other
end of the pipe instance is viewed as still connected from the point
of view of raw_read and determining EOF.
But it is not viewed as still connected if we are deciding whether to
unblock a new reader that is trying to open.
Cygwin: fifo: fix type of fifo_reader_id_t operators
fifo_reader_id_t::operator == and != have been defined without type
accidentally. For some weird reason, only x86 gcc complains about
this problem, not x86_64 gcc.
Ken Brown [Tue, 14 Apr 2020 13:45:44 +0000 (09:45 -0400)]
Cygwin: FIFO: update commentary
The beginning of fhandler_fifo.cc contains a long comment giving an
overview of the FIFO implementation. This is now updated to describe
the support for multiple readers.
Ken Brown [Wed, 6 May 2020 15:31:39 +0000 (11:31 -0400)]
Cygwin: FIFO: support opening multiple readers
Although we can have multiple readers open because of dup/fork/exec,
the current code does not support multiple readers opening a FIFO by
explicitly calling 'open'.
The main complication in supporting this is that when a blocking
reader tries to open and there's already one open, it has to check
whether there any writers open. It can't rely on the write_ready
event, whose state hasn't changed since the first writer opened.
To fix this, add two new named events, check_write_ready_evt and
write_ready_ok_evt, and a new method, check_write_ready().
The first event signals the owner's reader thread to call
check_write_ready(), which polls the fc_handler list to check for
connected writers. If it finds none, it checks to see if there's a
writer in the process and then sets/resets write_ready appropriately.
When check_write_ready() finishes it sets write_ready_ok_evt to signal
the reader that write_ready has been updated.
The polling is done via fifo_client_handler::pipe_state(). As long as
it's calling that function anyway, check_write_ready() updates the
state of each handler.
Also add a new lock to prevent a race if two readers are trying to
open simultaneously.
Ken Brown [Sat, 25 Apr 2020 13:54:18 +0000 (09:54 -0400)]
Cygwin: FIFO: allow any reader to take ownership
Add a take_ownership method, used by raw_read and select.cc:peek_fifo.
It wakes up all fifo_reader_threads and allows the caller to become
owner. The work is done by the fifo_reader_threads.
For synchronization we introduce several new fhandler_fifo data
members and methods:
- update_needed_evt signals the current owner to stop listening for
writer connections and update its fc_handler list.
- shared_fc_handler() gets and sets the status of the fc_handler
update process.
- get_pending_owner() and set_pending_owner() get and set the reader
that is requesting ownership.
Finally, a new 'reading_lock' prevents two readers from trying to take
ownership simultaneously.
Ken Brown [Fri, 24 Apr 2020 13:05:12 +0000 (09:05 -0400)]
Cygwin: FIFO: find a new owner when closing
If the owning reader is closing, wait for another reader (if there is
one) to take ownership before closing the owner's pipe handles.
To synchronize the ownership transfer, add events owner_needed_evt and
owner_found_evt, and add methods owner_needed and owner_found to
set/reset them.
Modify the fifo_reader_thread function to wake up all non-owners when
a new owner is needed.
Make a cosmetic change in close so that fhandler_base::close is called
only if we have a write handle. This prevents strace output from
being littered with statements that the null handle is being closed.
Ken Brown [Fri, 24 Apr 2020 01:29:32 +0000 (21:29 -0400)]
Cygwin: FIFO: take ownership on exec
If fixup_after_exec is called on a non-close-on-exec reader whose
parent is the owner, transfer ownership to the child. Otherwise the
parent's pipe handles will be closed before any other reader can
duplicate them.
To help with this, make the cancel_evt and thr_sync_evt handles
inheritable, so that the child can terminate the parent's
fifo_reader_thread (and the parent will update the shared fc_handler
list).
Add an optional argument 'from_exec' to update_my_handlers to simplify
its use in this case; no handle duplication is required.
Ken Brown [Thu, 23 Apr 2020 22:43:42 +0000 (18:43 -0400)]
Cygwin: FIFO: add a shared fifo_client_handler list
This is in a new shared memory section. We will use it for temporary
storage of the owner's fc_handler list when we need to change owner.
The new owner can then duplicate the pipe handles from that list
before taking ownership.
Add several shared data members and methods that are needed for the
duplication process
Add methods update_my_handlers and update_shared_handlers that carry
out the duplication.
Allow the shared list to grow dynamically, up to a point. Do this by
initially reserving a block of memory (currently 100 pages) and only
committing pages as needed.
Add methods create_shared_fc_handler, reopen_shared_fc_handler, and
remap_shared_fc_handler to create the new shared memory section,
reopen it, and commit new pages. The first is called in open, the
second is called in dup/fork/exec, and the third is called in
update_shared_handlers if more shared memory is needed.
Modify the fifo_reader_thread function to call update_my_handlers when
it finds that there is no owner. Also make it call
update_shared_handlers when the owner's thread terminates, so that the
new owner will have an accurate shared fc_handler list from which to
duplicate.
For convenience, add new methods cleanup_handlers and
close_all_handlers. And add an optional arg to add_client_handler
that allows it to create a new fifo_client_handler without creating a
new pipe instance.
Ken Brown [Thu, 2 Apr 2020 17:47:18 +0000 (13:47 -0400)]
Cygwin: FIFO: allow fc_handler list to grow dynamically
Make fc_handler a pointer to malloc'd memory instead of a fixed-size
array. The size is now a new data member 'shandlers'. Call realloc
in add_client_handler if we need to grow the array.
free fc_handler in close. As long as we're touching that code, also
remove an unneeded lock.
Ken Brown [Thu, 26 Mar 2020 18:32:10 +0000 (14:32 -0400)]
Cygwin: FIFO: designate one reader as owner
Among all the open readers of a FIFO, one is declared to be the owner.
This is the only reader that listens for client connections, and it is
the only one that has an accurate fc_handler list.
Add shared data and methods for getting and setting the owner, as well
as a lock to prevent more than one reader from accessing these data
simultaneously.
Modify the fifo_reader_thread so that it checks the owner at the
beginning of its loop. If there is no owner, it takes ownership. If
there is an owner but it is a different reader, the thread just waits
to be canceled. Otherwise, it listens for client connections as
before.
Remove the 'first' argument from create_pipe_instance. It is not
needed, and it may be confusing in the future since only the owner
knows whether a pipe instance is the first.
When opening a reader, don't return until the fifo_reader_thread has
time to set an owner.
If the owner closes, indicate that there is no longer an owner.
Clear the child's fc_handler list in dup, and don't bother duplicating
the handles. The child never starts out as owner, so it can't use
those handles.
Do the same thing in fixup_after_fork in the close-on-exec case. In
the non-close-on-exec case, the child inherits an fc_handler list that
it can't use, but we can just leave it alone; the handles will be
closed when the child is closed.
Ken Brown [Tue, 17 Mar 2020 16:29:56 +0000 (12:29 -0400)]
Cygwin: FIFO: add shared memory
Even though we currently allow a FIFO to be opened for reading only
once, we can still have more than one reader open because of dup and
fork. Add a named shared memory section accessible to all readers of
a given FIFO. In future commits we will add information needed by all
readers to this section
Add a class fifo_shmem_t that lets us access this information.
Add a method create_shmem that is called when a reader opens, and add
a method reopen_shmem that is called by dup, fork, and exec. (Each
new reader needs its own view of the shared memory.)
Ken Brown [Tue, 17 Mar 2020 18:14:47 +0000 (14:14 -0400)]
Cygwin: FIFO: make opening a writer more robust
- Make read_ready a manual-reset event.
- Signal read_ready in open instead of in the listen_client_thread.
- Don't reset read_ready when the listen_client thread terminates;
instead do it in close().
- Rearrange open and change its error handling.
- Add a wait_open_pipe method that waits for a pipe instance to be
available and then calls open_pipe. Use it when opening a writer if
we can't connect immediately. This can happen if the system is
heavily loaded and/or if many writers are trying to open
simultaneously.
Ken Brown [Sun, 26 Apr 2020 13:38:46 +0000 (09:38 -0400)]
Cygwin: FIFO: fix hit_eof
According to Posix, a FIFO open for reading is at EOF if it is empty
and there are no writers open.
The only way to test this is to poll the fifo_client_handlers as in
raw_read and select.cc:peek_fifo. The current hit_eof instead relies
on the value of nconnected, which can be out of date. On the one
hand, it doesn't take into account writers that were connected but
have since closed. On the other hand, it doesn't take into account
writers that are in the process of opening but haven't yet connected.
Fix this by introducing a maybe_eof method that tentatively assumes
EOF if there are no connected writers after polling. Then check for
writers currently opening (via a new 'writer_opening' event), and wait
for the fifo_reader_thread to record any new connection that was made
while we were polling.
To handle the needs of peek_fifo, replace the get_fc_handle method
by a get_fc_handler method, and add a fifo_client_handler::get_state
method.
Remove the is_connected method, which was used only in peek_fifo and
is no longer needed.
Remove the nconnected data member, which was used only for the flawed
hit_eof.
Ken Brown [Wed, 6 May 2020 22:39:26 +0000 (18:39 -0400)]
Cygwin: FIFO: change the fifo_client_connect_state enum
Make the values correspond to the possible return values of
fifo_client_handler::pipe_state().
When cleaning up the fc_handler list in listen_client_thread(), don't
delete handlers in the fc_closing state. I think the pipe might still
have input to be read in that case.
Set the state to fc_closing later in the same function if a connection
is made and the status returned by NtFsControlFile is
STATUS_PIPE_CLOSING.
In raw_read, don't error out if NtReadFile returns an unexpected
status; just set the state of that handler to fc_error. One writer in
a bad state doesn't justify giving up on reading.
Ken Brown [Mon, 16 Mar 2020 22:04:28 +0000 (18:04 -0400)]
Cygwin: FIFO: simplify the fifo_client_handler structure
Replace the 'fhandler_base *' member by a HANDLE to the server side of
the Windows named pipe instance. Make the corresponding
simplifications throughout.
When `cygwin-console-helper.exe` is either missing, or corresponds to a
different Cygwin runtime, we currently wait forever while setting up
access to the pseudo console, even long after the process is gone that
was supposed to signal that it set up access to the pseudo console.
Let's handle that more gracefully: if the process exited without
signaling, we cannot use the pseudo console. In that case, let's just
fall back to not using it.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The workaround to access the full disk required since Vista
and described in http://support.microsoft.com/kb/942448
(NOT ACCESSIBLE at the time of writing this commit message)
is required on floppy drives as well.
Cygwin: raw disk I/O: Fix return value in error case
The cast to generate the return value uses a DWORD variable
as test and set value. The error case is the constant -1.
Given the type of the other half of the conditioal expression,
-1 is cast to DWORD as well.
On 64 bit, this results in the error case returning a 32 bit
-1 value which is equivalent to (ssize_t) 4294967295 rather
than (ssize_t) -1.
Cygwin: accounts: Don't keep old schemes when parsing nsswitch.conf
The implicit assumption seemed to be that any subsequent occurence of
the same setting in nsswitch.conf is supposed to rewrite the previous
ones completely. This was not the case if the third or any further
schema was previously defined and the last line defined less than that
(but at least 2), for example:
```
db_home: windows cygwin /myhome/%U
db_home: cygwin desc
```
Let's document this behavior as well.
Signed-off-by: David Macek <david.macek.0@gmail.com>
Cygwin: symlinks: fix WSL symlink creation if cygdrive prefix is /
If the cygdrive prefix is /, then the following happens right now:
$ ln -s /tmp/foo .
$ ls -l foo
lrwxrwxrwx 1 user group 12 Apr 15 23:44 foo -> /mnt/tmp/foo
Fix this by skipping cygdrive prefix conversion to WSL drive
prefix "/mnt", if the cygdrive prefix is just "/". There's no
satisfying way to do the right thing all the time in this case
anyway. For a description and the alternatives, see
https://cygwin.com/pipermail/cygwin-developers/2020-April/011859.html
Cygwin: utils: override definition of PMEM_EXTENDED_PARAMETER
PMEM_EXTENDED_PARAMETER is defined in the local winlean.h as long
as mingw-w64 doesn't define it (in winnt.h). ntdll.h needs the
definition for declaring NtMapViewOfSectionEx. cygpath.cc and ps.cc
both include ntdll.h but not winlean.h, so they complain about the
missing definition.
Cygwin: threads: use extended memory API if available
So far Cygwin was jumping through hoops to restrict memory
allocation to specific regions. With the advent of VirtualAlloc2
and MapViewOfFile3 (and it's NT counterpart NtMapViewOfSectionEx),
we can skip searching for free space in the specific regions
and just call these functions and let the OS do the job more
efficiently and less racy.
Use VirtualAlloc2 on W10 1803 and later in thread stack allocation.
Cygwin: mmap: use extended memory API if available
So far Cygwin was jumping through hoops to restrict memory
allocation to specific regions. With the advent of VirtualAlloc2
and MapViewOfFile3 (and it's NT counterpart NtMapViewOfSectionEx),
we can skip searching for free space in the specific regions
and just call these functions and let the OS do the job more
efficiently and less racy.
Use the new functions on W10 1803 and later in mmap.
Windows 10 1803 introduced an extended memory API allowing
to specify memory regions allocations are to be taken off.
In preparation of using this API, define the struct
MEM_EXTENDED_PARAMETER and friends. Declare and allow to
autoload the functions VirtualAlloc2 and NtMapViewOfSectionEx.
Unfortunately Windows doesn't understand WSL symlinks,
despite being a really easy job. NT functions trying
to access paths traversing WSL symlinks return the status
code STATUS_IO_REPARSE_TAG_NOT_HANDLED. Handle this
status code same as STATUS_OBJECT_PATH_NOT_FOUND in
symlink_info::check to align behaviour to traversing
paths with other non-NTFS type symlinks.
Cygwin: symlinks: create WSL symlinks on supporting filesystems
WSL symlinks are reparse points containing a POSIX path in UTF-8.
On filesystems supporting reparse points, use this symlink type.
On other filesystems, or in case of error, fall back to the good
old plain SYSTEM file.
Cygwin: symlinks: fix WSL symlinks pointing to /mnt
Commit 4a36897af392 allowed to convert /mnt/<drive> path
prefixes to Cygwin cygdrive prefixes on the fly. However,
the patch neglected WSL symlinks pointing to the /mnt
directory. Rearrange path conversion so /mnt is converted
to the cygdrive prefix path itself.
Corinna Vinschen [Fri, 27 Mar 2020 11:12:31 +0000 (12:12 +0100)]
Cygwin: symlinks: support WSL symlinks
Treat WSL symlinks just like other symlinks. Convert
absolute paths pointing to Windows drives via
/mnt/<driveletter> to Windows-style paths <driveletter>:
newlib/libm/math: Make pow/powf return qnan for snan arg
The IEEE spec for pow only has special case for x**0 and 1**y when x/y
are quiet NaN. For signaling NaN, the general case applies and these functions
should signal the invalid exception and return a quiet NaN.
newlib/libm/common: Don't re-convert float to bits in modf/modff
These functions shared a pattern of re-converting the argument to bits
when returning +/-0. Skip that as the initial conversion still has the
sign bit.
Recent GCC appears to elide multiplication by 1, which causes snan
parameters to be returned unchanged through *iptr. Use the existing
conversion of snan to qnan to also set the correct result in *iptr
instead.
Joseph S. Myers [Wed, 25 Mar 2020 18:18:44 +0000 (11:18 -0700)]
Fix spurious underflow exceptions for Bessel functions for double(from glibc bug 14155)
This fix comes from glibc, from files which originated from
the same place as the newlib files. Those files in glibc carry
the same license as the newlib files.
Bug 14155 is spurious underflow exceptions from Bessel functions for
large arguments. (The correct results for large x are roughly
constant * sin or cos (x + constant) / sqrt (x), so no underflow
exceptions should occur based on the final result.)
There are various places underflows may occur in the intermediate
calculations that cause the failures listed in that bug. This patch
fixes problems for the double version where underflows occur in
calculating the intermediate functions P and Q (in particular, x**-12
gets computed while calculating Q). Appropriate approximations are
used for P and Q for arguments at least 0x1p28 and above to avoid the
underflows.
For sufficiently large x - 0x1p129 and above - the code already has a
cut-off to avoid calculating P and Q at all, which means the
approximations -0.125 / x and 0.375 / x can't themselves cause
underflows calculating Q. This cut-off is heuristically reasonable
for the point beyond which Q can be neglected (based on expecting
around 0x1p-64 to be the least absolute value of sin or cos for large
arguments representable in double).
The float versions use a cut-off 0x1p17, which is less heuristically
justifiable but should still only affect values near zeroes of the
Bessel functions where these implementations are intrinsically
inaccurate anyway (bugs 14469-14472), and should serve to avoid
underflows (the float underflow for jn in bug 14155 probably comes
from the recurrence to compute jn). ldbl-96 uses 0x1p129, which may
not really be enough heuristically (0x1p143 or so might be safer - 143
= 64 + 79, number of mantissa bits plus total number of significant
bits in representation) but again should avoid underflows and only
affect values where the code is substantially inaccurate anyway.
ldbl-128 and ldbl-128ibm share a completely different implementation
with no such cut-off, which I propose to fix separately.
Corinna Vinschen [Wed, 25 Mar 2020 11:21:59 +0000 (12:21 +0100)]
Cygwin: serial: read: if VMIN > 0, wait for VMIN chars in inbound queue
Per termios, read waits for MIN chars even if the number of requested
bytes is less. This requires to add WaitCommEvent to wait non-busily
for MIN chars prior to calling ReadFile, so, reintroduce it.
Corinna Vinschen [Mon, 23 Mar 2020 20:06:00 +0000 (21:06 +0100)]
Cygwin: serial: use per call OVERLAPPED structs
Sharing the OVERLAPPED struct and event object in there between
read and select calls in the fhandler might have been a nice
optimization way back when, but it is a dangerous, not thread-safe
approach. Fix this by creating per-fhandler, per-call OVERLAPPED
structs and event objects on demand.