Revamp advisory file locking to avoid cross reference pointers as well
as to allow BSD flock semantics. More agressively delete unused nodes
and sync objects.
* fhandler.h (fhandler_base::ino): Rename from namehash. Fix comment.
(fhandler_base::node): Remove.
(fhandler_base::unique_id): Add.
(fhandler_base::del_my_locks): New method.
(get_ino): Rename from get_namehash. Change usage throughout Cygwin.
(get_unique_id): New method.
* fhandler.cc (fhandler_base::close): Call own del_my_locks method.
Fix comment.
(fhandler_base::fhandler_base): Accommodate new and changed members.
(fhandler_base::fixup_after_fork): Call del_my_locks.
(fhandler_base::fixup_after_exec): Ditto for files with close-on-exec
flag set.
* fhandler_disk_file.cc (get_ino_by_handle): Rename from
readdir_get_ino_by_handle. Accommodate throughout.
(fhandler_base::open_fs): Fill ino with inode number if FS has good
inodes. Allocate a LUID and store in unique_id to recognize file
descriptors referencing the same file object.
* flock.cc: Drop flock TODO comments. Use explicit types __dev32_t
and __ino64_t instead of dev_t and ino_t.
(LOCK_OBJ_NAME_LEN): Change to reflect longer lf_id length.
(get_obj_handle_count): New method.
(lockf_t::lf_id): Change type to long long.
(inode_t::get_lock_obj_handle_count): Drop in favor of static function
get_obj_handle_count.
(inode_t::del_locks): Remove.
(inode_t::get): Add create_if_missing flag argument.
(inode_t::del_my_locks): Reimplement to handle POSIX and BSD flock
locks. Return if node can be deleted or not.
(inode_t::~inode_t): Ditto. Close handles to i_dir and i_mtx.
(fixup_lockf_after_fork): Remove.
(fhandler_base::del_my_locks): New method.
(fixup_lockf_after_exec): Check if node can be deleted.
(inode_t::get): Only create node if create_if_missing is set. Lock
the returned node here before unlocking the node list.
(inode_t::get_all_locks_list): Accommodate new lf_id length.
(inode_t::create_lock_obj): Ditto.
(lockf_t::open_lock_obj): Ditto. Change return type to bool. De-const.
Set lf_obj instead of returning a handle.
(lockf_t::del_lock_obj): Call SetEvent only if new incoming parameters
allow it. Explain how it's supposed to work.
(fhandler_disk_file::lock): Only fetch file length in SEEK_END case.
Use NtQueryInformationFile(FileStandardInformation) instead of
calling fstat_by_handle. Always unlock node before returning.
Use fhandler's unique id to create lf_id for BSD flock locks.
Rely on node lock from inode_t::get. Call del_lock_obj on removed
locks here to allow explicit unlocking. Delete node if no lock exists
on the file anymore.
(lf_setlock): Get file handle as additional parameter. Handle the fact
that lf_getblock now always opens the attached event object. Reactivate
erroneously applied patch which deactivates setting thread priority.
Additionally handle blocking on BSD flock locks.
(lf_clearlock): Get file handle as additional parameter.
(lf_getlock): Close event handle opened by lf_getblock.
(lf_getblock): Open potentially blocking event object here and check
its signal state if it's a BSD flock lock.
(lf_wakelock): Get file handle as additional parameter.
* fork.cc (frok::child): Drop call to fixup_lockf_after_fork.
* ntdll.h (struct _EVENT_BASIC_INFORMATION): Define.
(enum _EVENT_INFORMATION_CLASS): Define.
(NtQueryEvent): Declare.
* fhandler.h (fhandler_base::fs_flags): Remove.
(fhandler_base::set_fs_flags): Remove.
(fhandler_base::get_fs_flags): Remove.
* fhandler.cc (fhandler_base::write): Check for sparse file using
pc.fs_flags().
* fhandler_disk_file.cc (fhandler_disk_file::ftruncate): Ditto.
The return of the volume serial number in fs_info.
* fhandler.h (get_dev): New method.
* fhandler_disk_file.cc (fhandler_base::fstat_by_handle): Drop call to
NtQueryVolumeInformationFile(FileFsVolumeInformation). Just use
get_dev() method.
* fhandler_fifo.cc (fhandler_fifo::open) Use device ID and inode number
to generate fifo name.
* path.h (fs_info::sernum): New member.
(fs_info::serial_number): New method.
(path_conv::fs_serial_number): New method.
* path.cc (fs_info::update): Fetch volume serial number and store in
sernum.
cmalloc instead of ccalloc in the default operator. Add comments.
(inode_t::operator new): Call cmalloc instead of ccalloc.
(inode_t::get_all_locks_list): Return lockf_t pointer.
(inode_t::del_all_locks_list): Delete. Remove calls throughout.
(inode_t::get): Handle failing new gracefully.
(MAX_LOCKF_CNT): Define.
(inode_t::get_all_locks_list): Use pre-allocated buffer in i_all_lf
instead of allocating every lock. Return pointer to start of linked
list of locks.
(lockf_t::open_lock_obj): Create event object non-inheritable.
(fhandler_disk_file::lock): Handle failing new gracefully.
(lf_setlock): Allocate temporary buffer for node->i_all_lf from TLS.
Remove erroneous NtClose call.
(lf_getlock): Allocate temporary buffer for node->i_all_lf from TLS.
(lf_getblock): Set lf to return value of get_all_locks_list.
(FLOCK_INODE_DIR_ACCESS): Define.
(FLOCK_MUTANT_ACCESS): Define.
(FLOCK_EVENT_ACCESS): Define.
(SD_MIN_SIZE): Define.
(everyone_sd): Define to simplify calling _everyone_sd.
(_everyone_sd): Replace everyone_sync_sd. Take SECURITY_DESCRIPTOR as
argument and allow to specify access mask.
(get_lock_parent_dir): Open/Create parent dir with
FLOCK_PARENT_DIR_ACCESS. Add text to api_fatal message.
(inode_t::inode_t): Open/Create dir with FLOCK_INODE_DIR_ACCESS.
Open/Create mutant with FLOCK_MUTANT_ACCESS. Add text to api_fatal
message.
(lockf_t::create_lock_obj): Create event with FLOCK_EVENT_ACCESS.
Add text to api_fatal message.
(lockf_t::open_lock_obj): Open event with FLOCK_EVENT_ACCESS.
On failure, just return NULL pointer instead of calling api_fatal.
(lockf_t::get_lock_obj_handle_count): Replace call to small_printf
with call to debug_printf.
(lf_setlock): Handle a failure to open the lock event object as
EDEADLK. Call system_printf if opening sync objects fail.
* ntdll.h (DIRECTORY_TRAVERSE): Define.
(DIRECTORY_CREATE_OBJECT): Define.
(DIRECTORY_CREATE_SUBDIRECTORY): Define.
(EVENT_QUERY_STATE): Define.
in lock event object name.
(lockf_t::create_lock_obj): Ditto.
(lockf_t::open_lock_obj): Ditto.
(lf_setlock): Only check POSIX locks for deadlock condition.
(lf_findoverlap): Don't let POSIX and flock locks interact.
Corinna Vinschen