Commit Graph

802 Commits

Author SHA1 Message Date
Corinna Vinschen b6fbe0fc2e Cygwin: lseek: propagate new SEEK_DATA and SEEK_HOLE to fhandler
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2023-08-09 16:56:40 +02:00
Corinna Vinschen f48ce81122 Cygwin: Fix and streamline AT_EMPTY_PATH handling
The GLIBC extension AT_EMPTY_PATH allows the functions fchownat
and fstatat to operate on dirfd alone, if the given pathname is an
empty string.  This also allows to operate on any file type, not
only directories.

Commit fa84aa4dd2 broke this.  It only allows dirfd to be a
directory in calls to these two functions.

Fix that by handling AT_EMPTY_PATH right in gen_full_path_at.
A valid dirfd and an empty pathname is now a valid combination
and, noticably, this returns a valid path in path_ret.  That
in turn allows to remove the additional path generation code
from the callers.

Fixes: fa84aa4dd2 ("Cygwin: fix errno values set by readlinkat")
Reported-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Tested-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2023-07-26 15:14:33 +02:00
Corinna Vinschen 0051091999 Cygwin: use new _AT_NULL_PATHNAME_ALLOWED flag
Convert gen_full_path_at to take flag values from the caller, rather
than just a bool indicating that empty paths are allowed.  This is in
preparation of a better AT_EMPTY_PATH handling in a followup patch.

Reviewed-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2023-07-26 15:14:27 +02:00
Corinna Vinschen ae03aa7303 Cygwin: gen_full_path_at: drop never reached code
The check if the local variable p is NULL is useless.  The preceeding
code always sets p to a valid pointer, or it crashes if path_ret is
invalid (which would be a bug in Cygwin).

Fixes: c57b57e5c4 ("* cygwin.din: Sort.")
Reviewed-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2023-07-26 15:13:47 +02:00
Jon Turney 8b0b719d49
Cygwin: Fix uninitialized use of fh in strace output in stat_worker()
Move strace output to fix uninitalized use of fh introduced in previous commit.

../../../../src/winsup/cygwin/syscalls.cc: In function ‘int stat_worker(path_conv&, stat*)’:
../../../../src/winsup/cygwin/syscalls.cc:1971:69: error: ‘fh’ may be used uninitialized [-Werror=maybe-uninitialized]

Fixes: 42b44044b3 ("Cygwin: Fix Windows file handle leak in stat("file", -1)")
Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
2023-07-21 14:24:08 +01:00
Jon Turney 42b44044b3
Cygwin: Fix Windows file handle leak in stat("file", -1)
Don't leak a Windows file handle if stat() is called with a valid
filename, but invalid stat buffer pointer.

We do not destroy fh (which closes a Windows handle it has opened) if an
exception happens in the __try block.

Avoid this by re-ordering things so that we don't construct the fhandler
object until after we've attempted to use the struct stat buffer.

Fixes: 73151c54d5 ("syscalls.cc (stat_worker): Don't call build_fh_pc with invalid pc.")
Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
2023-07-21 13:23:33 +01:00
Corinna Vinschen d30a5917a9 Cygwin: align renameat2 to Linux behaviour
In contrast to rename default behaviour, Linux' renameat2 returns -1
with errno set to EEXIST, if oldfile and newfile refer to the same
file, and the RENAME_NOREPLACE flag is set.

Follow suit, given this is a Linux-only function anyway.

Fixes: f665b1cef3 ("cygwin: Implement renameat2")
Reported-by: Bruno Haible <bruno@clisp.org>
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2023-04-18 18:18:27 +02:00
Corinna Vinschen fa84aa4dd2 Cygwin: fix errno values set by readlinkat
readlinkat(fd, "", ...) is supposed to return ENOENT per POSIX,
but Cygwin returns EBADF.

At the same time, we have to maintain the special feature of
glibc that readlinkat(fd, "", ...) operates on fd, if fd is pointing
at a symlink opened with O_PATH|O_NOFOLLOW.

And, while fixing that, readlinkat(fd, path, ...) *still* has to set errno
to EBADF, if fd is an invalid descriptor *and* path is a relative path.

This required to change the evaluation order in the helper function
gen_full_path_at.

Last but not least, in case of the aforementioned glibc-like special
handling for symlink descriptors, we have to make sure that errors from
gen_full_path_at are not spilled into that special handling.

Fixes: 6cc05784e1 ("Cygwin: readlinkat: allow pathname to be empty")
Reported-by: Bruno Haible <bruno@clisp.org>
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2023-04-18 13:52:50 +02:00
Yoshinao Muramatsu 87ab6c7b26 Cygwin: log disabling posix semantics
Add log when workaround occurs

Signed-off-by: Yoshinao Muramatsu <ysno@ac.auone-net.jp>
2023-03-21 18:56:52 +01:00
Yoshinao Muramatsu 7666e248dd Cygwin: fix rename in container
Renaming files returns STATUS_INVALID_PARAMETE on a bind mounted file system
in hyper-v container with FILE_RENAME_POSIX_SEMANTICS.

Disable the use_posix_semantics flag and retry.

Signed-off-by: Yoshinao Muramatsu <ysno@ac.auone-net.jp>
2023-03-21 18:56:52 +01:00
Yoshinao Muramatsu 527dd1b407 Cygwin: fix unlink in container
Deleting files returns STATUS_INVALID_PARAMETE on a bind mounted file system
in hyper-v container with FILE_DISPOSITION_POSIX_SEMANTICS.
Therefore fall back to default method.

This code is suggested by Johannes Schindelin on github
and I change it more simple.

Signed-off-by: Yoshinao Muramatsu <ysno@ac.auone-net.jp>
2023-03-21 18:56:27 +01:00
Corinna Vinschen fe2545e9fa Cygwin: don't use unlink/rename POSIX semantics on certain NTFS
If a host NTFS is mapped into a Hyper-V isolated container, the
OPEN_BY_FILE_ID filesystem flag is missing, just as if that NTFS
is a remote drive.  However, NtQueryVolumeInformationFile claims
the drive is a local drive.

We can use this fact to learn that the process is running under
Hyper-V, and that the Hyper-V isolated process can't use rename/unlink
with POSIX semantics.  Strange enough, the POSIX_UNLINK_RENAME filesystem
flag is still set...

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2023-03-21 18:29:59 +01:00
Corinna Vinschen 271292b1fb Cygwin: unlink: drop unlink_nt/unlink_nt_shareable wrappers
Useless indirection.  Rename _unlink_nt back to unlink_nt
and call the function directly with `sharable' flag as needed.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2023-03-20 12:55:30 +01:00
Takashi Yano 93f70d7849 Cygwin: ctty: Remove old 'kludge' code.
Remove old 'kludge' code which does not seem necessary anymore. The
comment of the 'kludge' is as follows.

  * syscalls.cc (setsid): On second thought, in the spirit of keeping
    things kludgy, set ctty to -2 here as a special flag, and...
    (open): ...only eschew setting O_NOCTTY when that case is detected.

Fixes: c38a2d8373
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
2023-03-07 10:51:44 +09:00
Takashi Yano 13a84ac79b Cygwin: ctty: Replace ctty constant with more descriptive macros.
This patch replaces ctty constants with more descriptive macros
(CTTY_UNINITIALIZED and CTTY_RELEASED) rather than -1 and -2 as
well as checking sign with CTTY_IS_VALID().

Fixes: 3b7df69aaa (Cygwin: ctty: Add comments for the special values: -1 and -2.)
Suggested-by: Corinna Vinschen <corinna@vinschen.de>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
2023-03-07 10:51:29 +09:00
Takashi Yano 3b7df69aaa Cygwin: ctty: Add comments for the special values: -1 and -2.
_pinfo::ctty has two special values other than the device id of
the allocated ctty:
-1: CTTY is not initialized yet. Can be associated with the TTY
    which is associated with the session leader.
-2: CTTY has been released by setsid(). Can be associate only with
    new TTY which is not associated with any other session as CTTY,
    but cannot be associate with the TTYs already associated with
    other sessions.
This patch adds the comments in some source files.

Suggested-by: Corinna Vinschen <corinna@vinschen.de>
Signedoff-by: Takashi Yano <takashi.yano@nifty.ne.jp>
2023-01-10 22:04:40 +09:00
Corinna Vinschen 339bb6e932 Cygwin: stop handling files with .com suffix like .exe files
.com is a remnant from the past.  There are only five executables
left:

  chcp.com
  format.com
  mode.com
  more.com
  tree.com

Calling them on the command line already requires to use the
suffix anyway.  So drop useless .com test from the execve test
for scripts (they are handled earlier in the same function
as executables) and do not handle them like .exe suffixes in
other functions.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2022-10-28 12:44:27 +02:00
Corinna Vinschen 0819679a7a Cygwin: cwd: use SRWLOCK instead of muto
To reduce thread contention, use reader/writer locks as required.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2022-08-23 12:09:44 +02:00
Ken Brown c2aa5b6d74 Cygwin: syscalls.cc: remove ".dll" from blessed_executable_suffixes
This reverts commit d9e9c7b5a7.  The latter added ".dll" to the
blessed_executable_suffixes array because on 32-bit Windows, the
GetBinaryType function would report that a 64-bit DLL is an
executable, contrary to the documentation of that function.

That anomaly does not exist on 64-bit Windows, so we can remove ".dll"
from the list.  Reverting the commit does, however, change the
behavior of the rename(2) syscall in the following unlikely situation:
Suppose we have an executable foo.exe and we make the call

  rename ("foo", "bar.dll");

Previously, foo.exe would be renamed to bar.dll.  So bar.dll would
then be an executable without the .exe extension.  The new behavior is
that foo.exe will be renamed to bar.dll.exe.  [Exception: If there
already existed an executable (not a DLL!) with the name bar.dll, then
.exe will not be appended.]
2022-08-04 15:51:39 -04:00
Corinna Vinschen 7718cb70d4 Cygwin: syscalls.cc: drop masking macros for standard IO functions
The actual reason for these wrappers are lost in time, there's no
hint even in the pre-2000 ChangeLog files.  Apparently they were
masking the prototypes or, alternatively, macros from newlib to
clash with the definitions in syscalls.cc.

They are not needed anymore, so just drop them.

This uncovered that the buffer pointer to pwrite is erronously
non-const.  Fix this on the way out.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2022-08-04 20:32:49 +02:00
Corinna Vinschen 9f6057d203 Cygwin: Drop export aliases and masking macros for stdio64 functions
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2022-08-04 17:30:48 +02:00
Corinna Vinschen 8883f0ea39 Cygwin: drop macro and code for CYGWIN_VERSION_OLD_STDIO_CRLF_HANDLING
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2022-08-03 15:38:11 +02:00
Corinna Vinschen 2902b3a09e Cygwin: drop requirement to build newlib's stdio64
Given that 64 bit Cygwin defines all file access types (off_t,
fpos_t, and derived types) as 64 bit anyway, there's no reason
left to rely on the stdio64 part of newlib.  Use base functions
and base types.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2022-08-03 13:41:35 +02:00
Corinna Vinschen 7f42498be6 Cygwin: rename __cygwin_environ and drop env redirection via cur_environ()
Back in early Cygwin development a function based access to the
environment was exported, the internal environ in Cygwin was called
__cygwin_environ and cur_environ() was used to access the environment
indirectly .  The history of that necessity is not documented,
but kept in i686 for backward compatibility.

The x86_64 port eventually used __cygwin_environ directly and exported
it as DATA under the usual name environ.

We don't need the i686 workaround anymore, so just rename
__cygwin_environ to environ, drop the cur_environ() macro and
simply export environ under its own name.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2022-07-28 22:00:40 +02:00
Corinna Vinschen 1f962581ff Cygwin: fix or delete a few comments to drop 32 bit references
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2022-07-14 18:32:53 +02:00
Corinna Vinschen f25e61dfea Cygwin: drop tmpfile export alias for 32 bit systems
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2022-07-14 11:41:01 +02:00
Matt Joyce f3b8138239 Add _REENT_ERRNO(ptr)
Add a _REENT_ERRNO() macro to encapsulate the access to the
_errno member of struct reent. This will help to replace the
structure member with a thread-local storage object in a follow
up patch.

Replace uses of __errno_r() with _REENT_ERRNO().  Keep __errno_r() macro for
potential users outside of Newlib.
2022-07-13 06:55:41 +02:00
Ken Brown 2126f966ae Cygwin: remove regparm.h
This file defines the macros __reg1, __reg2, and __reg3, which are
defined to be empty on 64-bit Cygwin.  Remove all occurrences of these
macros.
2022-05-29 17:45:52 -04:00
Ken Brown 2d9b48760c Cygwin: simplify some function names
Remove "32" or "64" from each of the following names: acl32,
aclcheck32, aclfrommode32, aclfrompbits32, aclfromtext32, aclsort32,
acltomode32, acltopbits32, acltotext32, facl32, fchown32, fcntl64,
fstat64, _fstat64, _fstat64_r, ftruncate64, getgid32, getgrent32,
getgrgid32, getgrnam32, getgroups32, getpwuid32, getpwuid_r32,
getuid32, getuid32, initgroups32, lseek64, lstat64, mknod32, mmap64,
setegid32, seteuid32, setgid32, setgroups32, setregid32, setreuid32,
setuid32, stat64, _stat64_r, truncate64.

Remove prototypes and macro definitions of these names.

Remove "#ifndef __INSIDE_CYGWIN__" from some headers so that the new
names will be available when compiling Cygwin.

Remove aliases that are no longer needed.

Include <unistd.h> in fhandler_clipboard.cc for the declarations of
geteuid and getegid.
2022-05-29 17:45:52 -04:00
Ken Brown 7c0de0af97 Cygwin: remove some 32-bit-only function definitions
Remove the definitions of the following: acl, aclcheck, aclfrommode,
aclfrompbits, aclfromtext, aclsort, acltomode, acltopbits, acltotext,
chown, fchown, _fcntl, fstat, _fstat_r, ftruncate, getegid, geteuid, getgid,
getgrent, getgrgid, getgrnam, getgroups, getpwduid, getpwuid,
getpwuid_r, getuid, initgroups, lacl, lacl32, lchown, lseek, lstat,
mknod, mmap, setegid, seteuid, setgid, setgroups, setregid, setreuid,
setuid, stat, _stat_r, truncate.

[For most of these, the corresponding 64-bit entry points are obtained
by exporting aliases.  For example, acl is an alias for acl32, and
truncate is an alias for truncate64.]

Remove the following structs and all code using them (which is 32-bit
only): __stat32, __group16, __flock32, __aclent16_t.

Remove the typedefs of __blkcnt32_t __dev16_t, __ino32_t, which are
used only in code that has been removed.

Put the typedefs of __uid16_t and __gid16_t in one header, instead of
one header if __INSIDE_CYGWIN__ is defined and a different header
otherwise.
2022-05-29 17:45:52 -04:00
Ken Brown 2f8ba40046 Cygwin: fix mknod (64-bit only)
The current definition of mknod in syscalls.cc has a third argument of
type __dev16_t instead of dev_t.  Fix this on 64-bit Cygwin by making
the existing mknod 32-bit only and then exporting mknod as an alias
for mknod32.  (No fix is needed on 32-bit because mknod is redirected
to mknod32 via NEW_FUNCTIONS in Makefile.am.)

Addresses: https://cygwin.com/pipermail/cygwin-developers/2022-May/012589.html
2022-05-23 08:16:40 -04:00
Corinna Vinschen ca313dd8f4 Cygwin: drop create_token and dependent functions
Given we only called create_token on W7 WOW64 anyway, we can now
drop this function and all other functions only called from there
entirely.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2022-05-13 14:21:52 +02:00
Corinna Vinschen 2610b681a4 Cygwin: wincap: drop wow64 flag and all conditions depending on it
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2022-05-13 14:15:47 +02:00
Matt Joyce 8b96542ed1 Add global __sglue object for all configurations
Added a new global __sglue object for all configurations.
Decouples the global file object list from the _GLOBAL_REENT
structure by using this new object instead of the __sglue member
of _GLOBAL_REENT in __sfp() and _fwalk_sglue().
2022-05-13 12:41:10 +02:00
Sebastian Huber 3941c8a88a stdio: Replace _fwalk_reent() with _fwalk_sglue()
Replaced _fwalk_reent() with _fwalk_sglue(). The change adds an
extra __sglue object as a parameter, which will allow the passing
of a global __sglue object separate from the __sglue member of
struct _reent. The global __sglue object will be added in a
follow-on patch.
2022-05-13 12:40:10 +02:00
Sebastian Huber 7a5903078d Replace _fwalk() calls with _fwalk_reent()
Remove the _fwalk() implementation to avoid duplicated code with
_fwalk_reent().
2022-03-31 07:54:04 +02:00
Corinna Vinschen f2dc492df0 Cygwin: unlink: filter out virtual files and devices early on
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2022-02-22 13:33:06 +01:00
Corinna Vinschen 7e7d471644 Cygwin: introduce isabspath_strict macro
isabspath handles a path "X:", without trailing slash or backslash,
as absolute path.  This breaks some scenarios with relative paths
starting with "X:".  For instance, fstatat will mishandle a call
with valid dirfd and "c:" as path.

The reason is that gen_full_path_at() will check for isabspath("C:")
which returns true.  So the path will be used verbatim in fstatat,
rather than being converted to a path "<dirfd-path>/c:".

So, introduce isabspath_strict, which returns true for paths starting
with "X:" only if the next char is actually a slash or backslash.
Use it from gen_full_path_at().

This still fixes only half the problem.  The right thing would have been
to disallow using DOS paths in the first place.  Unfortunately it's much
too late for that.

Addresses: https://cygwin.com/pipermail/cygwin/2021-November/249837.html
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2021-11-11 10:48:22 +01:00
Corinna Vinschen a4efb2a669 Cygwin: remove support for Vista entirely
Fix up a few comments while at it

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2021-10-29 18:19:45 +02:00
Takashi Yano 350806f882 Cygwin: close_all_files: Do not duplicate stderr for write pipe.
- Currently, the stderr handle is duplicated in close_all_files().
  This interferes the handle counting for detecting closure of read
  pipe, which is introduced by commit f79a4611. This patch stops
  duplicating stderr handle if it is write pipe.
2021-09-16 10:57:14 -04:00
Corinna Vinschen 9cfbb5aa82 Cygwin: _pipe: add a comment
I wasted valuable minutes of my life just to find out why we export
this weird version of pipe.  In the pre-2000 era the idea was Cygwin
could be used as drop-in replacement for msvcrt.dll, apparently.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2021-09-13 17:45:53 +02:00
Ken Brown f002d02b17 Cygwin: remove the fhandler_base_overlapped class
Also remove the 'was_nonblocking' flag, which was needed only for
fhandler_base_overlapped.
2021-09-13 17:45:53 +02:00
Corinna Vinschen eeeb5650cf Cygwin: fix declaration of RtlInitEmptyUnicodeString
This avoids "-Werror=maybe-uninitialized" errors due to
using WCSTR accidentally.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2021-09-03 13:16:48 +02:00
Corinna Vinschen 2f05de4dbf Cygwin: fix all usages of NtQueryDirectoryObject
Due to reports on the Cygwin mailing list[1][2], it was uncovered
that a NtOpenDirectoryObject/NtQueryDirectoryObject/NtClose sequence
with NtQueryDirectoryObject iterating over the directory entries,
one entry per invocation, is not running atomically.  If new entries
are inserted into the queried directory, other entries may be moved
around and then accidentally show up twice while iterating.

Change (almost) all NtQueryDirectoryObject invocations so that it gets
a really big buffer (64K) and ideally fetches all entries at once.
This appears to work atomically.

"Almost" all, because fhandler_procsys::readdir can't be easily changed.

[1] https://cygwin.com/pipermail/cygwin/2021-July/248998.html
[2] https://cygwin.com/pipermail/cygwin/2021-August/249124.html

Fixes: e9c8cb3193 ("(format_proc_partitions): Revamp loop over existing harddisks by scanning the NT native \Device object directory and looking for Harddisk entries.")
Fixes: a998dd7055 ("Implement advisory file locking.")
Fixes: 3b7cd74bfd ("(winpids::enum_processes): Fetch Cygwin processes from listing of shared cygwin object dir in the native NT namespace.")
Fixes: 0d6f2b0117 ("syscalls.cc (sync_worker): Rewrite using native NT functions.")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2021-08-19 16:42:23 +02:00
Ken Brown 182ba1f022 Cygwin: simplify linkat with AT_EMPTY_PATH
linkat(olddirfd, oldpath, oldname, newdirfd, newname, AT_EMPTY_PATH)
is supposed to create a link to the file referenced by olddirfd if
oldname is the empty string.  Currently this is done via the /proc
filesystem by converting the call to

  linkat(AT_FDCWD, "/proc/self/fd/<olddirfd>", newdirfd, newname,
         AT_SYMLINK_FOLLOW),

which ultimately leads to a call to the appropriate fhandler's link
method.  Simplify this by using cygheap_fdget to obtain the fhandler
directly.
2021-02-25 17:44:18 -05:00
Ken Brown 246121534a Cygwin: FIFO: temporarily keep a conv_handle in syscalls.cc:open
When a FIFO is opened, syscalls.cc:open always calls fstat on the
newly-created fhandler_fifo.  This results from a call to
device_access_denied.

To speed-up this fstat call, and therefore the open(2) call, use
PC_KEEP_HANDLE when the fhandler is created.  The resulting
conv_handle is retained until after the fstat call if the fhandler is
a FIFO; otherwise, it is closed immediately.
2021-02-19 13:43:33 -05:00
Corinna Vinschen 67043f48dc Cygwin: only export tmpfile64 on 32 bit
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2021-02-12 10:24:54 +01:00
Mark Geisert 62ee6581a5 Cygwin: Have tmpfile(3) use O_TMPFILE
Per discussion on cygwin-developers, a Cygwin tmpfile(3) implementation
has been added to syscalls.cc.  This overrides the one supplied by
newlib.  Then the open(2) flag O_TMPFILE was added to the open call that
tmpfile internally makes.

This v2 patch removes O_CREAT from open() call as O_TMPFILE obviates it.
Note that open() takes a directory's path but returns an fd to a file.
2021-02-12 10:18:25 +01:00
Ken Brown 5b8358e6ed Cygwin: remove the OPEN_MAX_MAX macro
Replace all occurrences of OPEN_MAX_MAX by OPEN_MAX, and define the
latter to be 3200, which was the value of the former.  In view of the
recent change to getdtablesize, there is no longer a need to
distinguish between these two macros.
2021-02-01 09:55:08 -05:00
Ken Brown 3d256e22e2 Cygwin: getdtablesize: always return OPEN_MAX_MAX
According to the Linux man page for getdtablesize(3), the latter is
supposed to return "the maximum number of files a process can have
open, one more than the largest possible value for a file descriptor."
The constant OPEN_MAX_MAX is the only limit enforced by Cygwin, so we
now return that.

Previously getdtablesize returned the current size of cygheap->fdtab,
Cygwin's internal file descriptor table.  But this is a dynamically
growing table, and its current size does not reflect an actual limit
on the number of open files.

With this change, gnulib now reports that getdtablesize and
fcntl(F_DUPFD) work on Cygwin.  Packages like GNU tar that use the
corresponding gnulib modules will no longer use gnulib replacements on
Cygwin.
2021-02-01 09:55:07 -05:00