* flock.cc (LOCK_DIR_NAME_FMT): Define.

(LOCK_DIR_NAME_LEN): Define.
	(LOCK_DIR_NAME_DEV_OFF): Define.
	(LOCK_DIR_NAME_INO_OFF): Define.
	(LOCK_OBJ_NAME_FMT): Define.  Add comment.
	(class lockf_t): Use bitsize-explicit types.  Declare from_obj_name,
	(class inode_t): Make use, unuse and inuse methods public.  Add a
	lock argument to get method declaration.
	(inode_t::get): Add lock argument.  Only lock node if lock arg is true.
	(inode_t::inode_t): Use LOCK_DIR_NAME_FMT as format string.
	(lockf_t::from_obj_name): New method to generate lockf_t content from
	lock event object basename.
	(inode_t::get_all_locks_list): Just call from_obj_name here and copy
	result into final lockf_t.
	(create_lock_obj_attr): Use LOCK_OBJ_NAME_FMT as format string.
	(create_lock_in_parent): New thread function to create lockf_t
	structure in parent process.
	(delete_lock_in_parent): New thread function to reap stale BSD locks in
	parent process.
	(lockf_t::create_lock_obj): Try to duplicate lock object handle into
	parent process and call create_lock_in_parent as parent remote thread.
	(lockf_t::del_lock_obj): Call delete_lock_in_parent as parent remote
	thread.
	(fhandler_disk_file::lock): Add lock arg to inode_t::get call.
This commit is contained in:
Corinna Vinschen 2012-02-26 12:34:17 +00:00
parent 3a90360cf0
commit dbf576fd86
2 changed files with 278 additions and 45 deletions

View File

@ -1,3 +1,30 @@
2012-02-26 Corinna Vinschen <corinna@vinschen.de>
* flock.cc (LOCK_DIR_NAME_FMT): Define.
(LOCK_DIR_NAME_LEN): Define.
(LOCK_DIR_NAME_DEV_OFF): Define.
(LOCK_DIR_NAME_INO_OFF): Define.
(LOCK_OBJ_NAME_FMT): Define. Add comment.
(class lockf_t): Use bitsize-explicit types. Declare from_obj_name,
(class inode_t): Make use, unuse and inuse methods public. Add a
lock argument to get method declaration.
(inode_t::get): Add lock argument. Only lock node if lock arg is true.
(inode_t::inode_t): Use LOCK_DIR_NAME_FMT as format string.
(lockf_t::from_obj_name): New method to generate lockf_t content from
lock event object basename.
(inode_t::get_all_locks_list): Just call from_obj_name here and copy
result into final lockf_t.
(create_lock_obj_attr): Use LOCK_OBJ_NAME_FMT as format string.
(create_lock_in_parent): New thread function to create lockf_t
structure in parent process.
(delete_lock_in_parent): New thread function to reap stale BSD locks in
parent process.
(lockf_t::create_lock_obj): Try to duplicate lock object handle into
parent process and call create_lock_in_parent as parent remote thread.
(lockf_t::del_lock_obj): Call delete_lock_in_parent as parent remote
thread.
(fhandler_disk_file::lock): Add lock arg to inode_t::get call.
2012-02-25 Christopher Faylor <me.cygwin2012@cgf.cx>
* include/cygwin/version.h (CYGWIN_VERSION_DLL_MINOR): Bump to 12.

View File

@ -124,7 +124,14 @@ static NO_COPY muto lockf_guard;
#define INODE_LIST_LOCK() (lockf_guard.init ("lockf_guard")->acquire ())
#define INODE_LIST_UNLOCK() (lockf_guard.release ())
#define LOCK_OBJ_NAME_LEN 69
#define LOCK_DIR_NAME_FMT L"flock-%08x-%016X"
#define LOCK_DIR_NAME_LEN 31 /* Length of the resulting name */
#define LOCK_DIR_NAME_DEV_OFF 6 /* Offset to device number */
#define LOCK_DIR_NAME_INO_OFF 15 /* Offset to inode number */
/* Don't change format without also changing lockf_t::from_obj_name! */
#define LOCK_OBJ_NAME_FMT L"%02x-%01x-%016X-%016X-%016X-%08x-%04x"
#define LOCK_OBJ_NAME_LEN 69 /* Length of the resulting name */
#define FLOCK_INODE_DIR_ACCESS (DIRECTORY_QUERY \
| DIRECTORY_TRAVERSE \
@ -225,11 +232,11 @@ struct lockfattr_t
class lockf_t
{
public:
short lf_flags; /* Semantics: F_POSIX, F_FLOCK, F_WAIT */
short lf_type; /* Lock type: F_RDLCK, F_WRLCK */
uint16_t lf_flags; /* Semantics: F_POSIX, F_FLOCK, F_WAIT */
uint16_t lf_type; /* Lock type: F_RDLCK, F_WRLCK */
_off64_t lf_start; /* Byte # of the start of the lock */
_off64_t lf_end; /* Byte # of the end of the lock (-1=EOF) */
long long lf_id; /* Cygwin PID for POSIX locks, a unique id per
int64_t lf_id; /* Cygwin PID for POSIX locks, a unique id per
file table entry for BSD flock locks. */
DWORD lf_wid; /* Win PID of the resource holding the lock */
uint16_t lf_ver; /* Version number of the lock. If a released
@ -255,6 +262,9 @@ class lockf_t
{}
~lockf_t ();
bool from_obj_name (class inode_t *node, class lockf_t **head,
const wchar_t *name);
/* Used to create all locks list in a given TLS buffer. */
void *operator new (size_t size, void *p)
{ return p; }
@ -292,10 +302,6 @@ class inode_t
HANDLE i_mtx;
uint32_t i_cnt; /* # of threads referencing this instance. */
void use () { ++i_cnt; }
void unuse () { if (i_cnt > 0) --i_cnt; }
bool inuse () { return i_cnt > 0; }
public:
inode_t (__dev32_t dev, __ino64_t ino);
~inode_t ();
@ -305,11 +311,15 @@ class inode_t
void operator delete (void *p)
{ cfree (p); }
static inode_t *get (__dev32_t dev, __ino64_t ino, bool create_if_missing);
static inode_t *get (__dev32_t dev, __ino64_t ino,
bool create_if_missing, bool lock);
void LOCK () { WaitForSingleObject (i_mtx, INFINITE); }
void UNLOCK () { ReleaseMutex (i_mtx); }
void use () { ++i_cnt; }
void unuse () { if (i_cnt > 0) --i_cnt; }
bool inuse () { return i_cnt > 0; }
void notused () { i_cnt = 0; }
void unlock_and_remove_if_unused ();
@ -390,7 +400,7 @@ inode_t::del_my_locks (long long id, HANDLE fhdl)
void
fhandler_base::del_my_locks (del_lock_called_from from)
{
inode_t *node = inode_t::get (get_dev (), get_ino (), false);
inode_t *node = inode_t::get (get_dev (), get_ino (), false, true);
if (node)
{
/* When we're called from fixup_after_exec, the fhandler is a
@ -458,7 +468,7 @@ fixup_lockf_after_exec ()
file. The file is specified by the device and inode_t number. If inode_t
doesn't exist, create it. */
inode_t *
inode_t::get (__dev32_t dev, __ino64_t ino, bool create_if_missing)
inode_t::get (__dev32_t dev, __ino64_t ino, bool create_if_missing, bool lock)
{
inode_t *node;
@ -475,7 +485,7 @@ inode_t::get (__dev32_t dev, __ino64_t ino, bool create_if_missing)
if (node)
node->use ();
INODE_LIST_UNLOCK ();
if (node)
if (node && lock)
node->LOCK ();
return node;
}
@ -492,7 +502,7 @@ inode_t::inode_t (__dev32_t dev, __ino64_t ino)
parent_dir = get_shared_parent_dir ();
/* Create a subdir which is named after the device and inode_t numbers
of the given file, in hex notation. */
int len = __small_swprintf (name, L"flock-%08x-%016X", dev, ino);
int len = __small_swprintf (name, LOCK_DIR_NAME_FMT, dev, ino);
RtlInitCountedUnicodeString (&uname, name, len * sizeof (WCHAR));
InitializeObjectAttributes (&attr, &uname, OBJ_INHERIT | OBJ_OPENIF,
parent_dir, everyone_sd (FLOCK_INODE_DIR_ACCESS));
@ -516,6 +526,45 @@ inode_t::inode_t (__dev32_t dev, __ino64_t ino)
#define MAX_LOCKF_CNT ((intptr_t)((NT_MAX_PATH * sizeof (WCHAR)) \
/ sizeof (lockf_t)))
bool
lockf_t::from_obj_name (inode_t *node, lockf_t **head, const wchar_t *name)
{
wchar_t *endptr;
/* "%02x-%01x-%016X-%016X-%016X-%08x-%04x",
lf_flags, lf_type, lf_start, lf_end, lf_id, lf_wid, lf_ver */
lf_flags = wcstol (name, &endptr, 16);
if ((lf_flags & ~(F_FLOCK | F_POSIX)) != 0
|| ((lf_flags & (F_FLOCK | F_POSIX)) == (F_FLOCK | F_POSIX)))
return false;
lf_type = wcstol (endptr + 1, &endptr, 16);
if ((lf_type != F_RDLCK && lf_type != F_WRLCK) || !endptr || *endptr != L'-')
return false;
lf_start = (_off64_t) wcstoull (endptr + 1, &endptr, 16);
if (lf_start < 0 || !endptr || *endptr != L'-')
return false;
lf_end = (_off64_t) wcstoull (endptr + 1, &endptr, 16);
if (lf_end < -1LL
|| (lf_end > 0 && lf_end < lf_start)
|| !endptr || *endptr != L'-')
return false;
lf_id = wcstoll (endptr + 1, &endptr, 16);
if (!endptr || *endptr != L'-'
|| ((lf_flags & F_POSIX) && (lf_id < 1 || lf_id > ULONG_MAX)))
return false;
lf_wid = wcstoul (endptr + 1, &endptr, 16);
if (!endptr || *endptr != L'-')
return false;
lf_ver = wcstoul (endptr + 1, &endptr, 16);
if (endptr && *endptr != L'\0')
return false;
lf_head = head;
lf_inode = node;
lf_next = NULL;
lf_obj = NULL;
return true;
}
lockf_t *
inode_t::get_all_locks_list ()
{
@ -526,7 +575,7 @@ inode_t::get_all_locks_list ()
} f;
ULONG context;
NTSTATUS status;
lockf_t *lock = i_all_lf;
lockf_t newlock, *lock = i_all_lf;
for (BOOLEAN restart = TRUE;
NT_SUCCESS (status = NtQueryDirectoryObject (i_dir, &f, sizeof f, TRUE,
@ -535,32 +584,8 @@ inode_t::get_all_locks_list ()
{
if (f.dbi.ObjectName.Length != LOCK_OBJ_NAME_LEN * sizeof (WCHAR))
continue;
wchar_t *wc = f.dbi.ObjectName.Buffer, *endptr;
/* "%02x-%01x-%016X-%016X-%016X-%08x-%04x",
lf_flags, lf_type, lf_start, lf_end, lf_id, lf_wid, lf_ver */
wc[LOCK_OBJ_NAME_LEN] = L'\0';
short flags = wcstol (wc, &endptr, 16);
if ((flags & ~(F_FLOCK | F_POSIX)) != 0
|| ((flags & (F_FLOCK | F_POSIX)) == (F_FLOCK | F_POSIX)))
continue;
short type = wcstol (endptr + 1, &endptr, 16);
if ((type != F_RDLCK && type != F_WRLCK) || !endptr || *endptr != L'-')
continue;
_off64_t start = (_off64_t) wcstoull (endptr + 1, &endptr, 16);
if (start < 0 || !endptr || *endptr != L'-')
continue;
_off64_t end = (_off64_t) wcstoull (endptr + 1, &endptr, 16);
if (end < -1LL || (end > 0 && end < start) || !endptr || *endptr != L'-')
continue;
long long id = wcstoll (endptr + 1, &endptr, 16);
if (!endptr || *endptr != L'-'
|| ((flags & F_POSIX) && (id < 1 || id > ULONG_MAX)))
continue;
DWORD wid = wcstoul (endptr + 1, &endptr, 16);
if (!endptr || *endptr != L'-')
continue;
uint16_t ver = wcstoul (endptr + 1, &endptr, 16);
if (endptr && *endptr != L'\0')
f.dbi.ObjectName.Buffer[LOCK_OBJ_NAME_LEN] = L'\0';
if (!newlock.from_obj_name (this, &i_all_lf, f.dbi.ObjectName.Buffer))
continue;
if (lock - i_all_lf >= MAX_LOCKF_CNT)
{
@ -570,8 +595,7 @@ inode_t::get_all_locks_list ()
}
if (lock > i_all_lf)
lock[-1].lf_next = lock;
new (lock++) lockf_t (this, &i_all_lf,
flags, type, start, end, id, wid, ver);
new (lock++) lockf_t (newlock);
}
/* If no lock has been found, return NULL. */
if (lock == i_all_lf)
@ -584,7 +608,7 @@ inode_t::get_all_locks_list ()
POBJECT_ATTRIBUTES
lockf_t::create_lock_obj_attr (lockfattr_t *attr, ULONG flags)
{
__small_swprintf (attr->name, L"%02x-%01x-%016X-%016X-%016X-%08x-%04x",
__small_swprintf (attr->name, LOCK_OBJ_NAME_FMT,
lf_flags & (F_POSIX | F_FLOCK), lf_type, lf_start, lf_end,
lf_id, lf_wid, lf_ver);
RtlInitCountedUnicodeString (&attr->uname, attr->name,
@ -594,6 +618,111 @@ lockf_t::create_lock_obj_attr (lockfattr_t *attr, ULONG flags)
return &attr->attr;
}
DWORD WINAPI
create_lock_in_parent (PVOID param)
{
HANDLE lf_obj;
ULONG size;
OBJECT_NAME_INFORMATION *ntfn;
NTSTATUS status;
wchar_t *lockname, *inodename, *endptr;
__dev32_t dev;
__ino64_t ino;
inode_t *node;
lockf_t newlock, *lock;
int cnt;
/* param is the handle to the lock object, created by caller. */
lf_obj = (HANDLE) param;
/* Fetch object path from handle. Typically the length of the path
is 146 characters, starting with
"\BaseNamedObject\cygwin-1S5-<16-hex-digits>\..." */
size = sizeof (OBJECT_NAME_INFORMATION) + 256 * sizeof (WCHAR);
ntfn = (OBJECT_NAME_INFORMATION *) alloca (size);
memset (ntfn, 0, size);
status = NtQueryObject (lf_obj, ObjectNameInformation, ntfn, size, &size);
if (!NT_SUCCESS (status))
goto err;
ntfn->Name.Buffer[ntfn->Name.Length / sizeof (WCHAR)] = L'\0';
/* Sanity check so that we don't peek into unchartered territory. */
if (ntfn->Name.Length < LOCK_OBJ_NAME_LEN + LOCK_DIR_NAME_LEN + 1)
goto err;
/* The names have fixed size, so we know where the substrings start. */
lockname = ntfn->Name.Buffer + ntfn->Name.Length / sizeof (WCHAR)
- LOCK_OBJ_NAME_LEN;
inodename = lockname - LOCK_DIR_NAME_LEN - 1;
dev = wcstoul (inodename + LOCK_DIR_NAME_DEV_OFF, &endptr, 16);
if (*endptr != L'-')
goto err;
ino = wcstoull (inodename + LOCK_DIR_NAME_INO_OFF, &endptr, 16);
if (*endptr != L'\\')
goto err;
if (!newlock.from_obj_name (NULL, NULL, lockname))
goto err;
/* Check if we have an open file handle with the same unique id. */
{
cnt = 0;
cygheap_fdenum cfd (true);
while (cfd.next () >= 0)
if (cfd->get_unique_id () == newlock.lf_id && ++cnt > 0)
break;
}
/* If not, close handle and return. */
if (!cnt)
{
NtClose (lf_obj);
return 0;
}
/* otherwise generate inode from directory name... */
node = inode_t::get (dev, ino, true, false);
/* ...and generate lock from object name. */
lock = new lockf_t (newlock);
lock->lf_inode = node;
lock->lf_head = &node->i_lockf;
lock->lf_next = node->i_lockf;
lock->lf_obj = lf_obj;
node->i_lockf = lock;
node->unuse ();
return 0;
err:
system_printf ("Adding <%S> lock failed", &ntfn->Name);
NtClose (lf_obj);
return 1;
}
DWORD WINAPI
delete_lock_in_parent (PVOID param)
{
inode_t *node;
lockf_t *lock, **prev;
/* Scan list of all inodes, and reap stale BSD lock if lf_id matches.
Remove inode if empty. */
INODE_LIST_LOCK ();
LIST_FOREACH (node, &cygheap->inode_list, i_next)
if (!node->inuse ())
{
for (prev = &node->i_lockf, lock = *prev; lock; lock = *prev)
{
if ((lock->lf_flags & F_FLOCK) && IsEventSignalled (lock->lf_obj))
{
*prev = lock->lf_next;
delete lock;
}
else
prev = &lock->lf_next;
}
if (node->i_lockf == NULL)
{
LIST_REMOVE (node, i_next);
delete node;
}
}
INODE_LIST_UNLOCK ();
return 0;
}
/* Create the lock event object in the file's subdir in the NT global
namespace. */
void
@ -629,6 +758,54 @@ lockf_t::create_lock_obj ()
}
}
while (!NT_SUCCESS (status));
/* For BSD locks, notify the parent process. */
if (lf_flags & F_FLOCK)
{
HANDLE parent_proc, parent_thread, parent_lf_obj;
pinfo p (myself->ppid);
if (!p) /* No access or not a Cygwin parent. */
return;
parent_proc = OpenProcess (PROCESS_DUP_HANDLE
| PROCESS_CREATE_THREAD
| PROCESS_QUERY_INFORMATION
| PROCESS_VM_OPERATION
| PROCESS_VM_WRITE
| PROCESS_VM_READ,
FALSE, p->dwProcessId);
if (!parent_proc)
{
debug_printf ("OpenProcess (%u): %E", p->dwProcessId);
return;
}
if (!DuplicateHandle (GetCurrentProcess (), lf_obj, parent_proc,
&parent_lf_obj, TRUE, 0, DUPLICATE_SAME_ACCESS))
debug_printf ("DuplicateHandle (lf_obj): %E");
else
{
parent_thread = CreateRemoteThread (parent_proc, NULL, 256 * 1024,
create_lock_in_parent,
parent_lf_obj,
STACK_SIZE_PARAM_IS_A_RESERVATION,
NULL);
if (!parent_thread)
{
debug_printf ("CreateRemoteThread: %E");
/* If thread didn't get started, close object handle in parent,
otherwise suffer handle leaks. */
DuplicateHandle (parent_proc, parent_lf_obj, parent_proc,
NULL, 0, FALSE, DUPLICATE_CLOSE_SOURCE);
}
else
{
/* Must wait to avoid race conditions. */
WaitForSingleObject (parent_thread, INFINITE);
CloseHandle (parent_thread);
}
}
CloseHandle (parent_proc);
}
}
/* Open a lock event object for SYNCHRONIZE access (to wait for it). */
@ -665,7 +842,36 @@ lockf_t::del_lock_obj (HANDLE fhdl, bool signal)
handle/descriptor to the same FILE_OBJECT/file table entry. */
if ((lf_flags & F_POSIX) || signal
|| (fhdl && get_obj_handle_count (fhdl) <= 1))
NtSetEvent (lf_obj, NULL);
{
NtSetEvent (lf_obj, NULL);
/* For BSD locks, notify the parent process. */
if (lf_flags & F_FLOCK)
{
HANDLE parent_proc, parent_thread;
pinfo p (myself->ppid);
if (p && (parent_proc = OpenProcess (PROCESS_CREATE_THREAD
| PROCESS_QUERY_INFORMATION
| PROCESS_VM_OPERATION
| PROCESS_VM_WRITE
| PROCESS_VM_READ,
FALSE, p->dwProcessId)))
{
parent_thread = CreateRemoteThread (parent_proc, NULL,
256 * 1024, delete_lock_in_parent,
NULL,
STACK_SIZE_PARAM_IS_A_RESERVATION,
NULL);
if (parent_thread)
{
/* Must wait to avoid race conditions. */
WaitForSingleObject (parent_thread, INFINITE);
CloseHandle (parent_thread);
}
CloseHandle (parent_proc);
}
}
}
close_lock_obj ();
}
}
@ -815,7 +1021,7 @@ fhandler_disk_file::lock (int a_op, struct __flock64 *fl)
restart: /* Entry point after a restartable signal came in. */
inode_t *node = inode_t::get (get_dev (), get_ino (), true);
inode_t *node = inode_t::get (get_dev (), get_ino (), true, true);
if (!node)
{
set_errno (ENOLCK);