1 files changed, 411 insertions, 0 deletions

diff --git a/source4/ntvfs/posix/pvfs_lock.c b/source4/ntvfs/posix/pvfs_lock.c
new file mode 100644
index 0000000..54c7a33
--- /dev/null
+++ b/source4/ntvfs/posix/pvfs_lock.c
@@ -0,0 +1,411 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   POSIX NTVFS backend - locking
+
+   Copyright (C) Andrew Tridgell 2004
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "vfs_posix.h"
+#include "system/time.h"
+#include "../lib/util/dlinklist.h"
+#include "messaging/messaging.h"
+
+
+/*
+  check if we can perform IO on a range that might be locked
+*/
+NTSTATUS pvfs_check_lock(struct pvfs_state *pvfs,
+			 struct pvfs_file *f,
+			 uint32_t smbpid,
+			 uint64_t offset, uint64_t count,
+			 enum brl_type rw)
+{
+	if (!(pvfs->flags & PVFS_FLAG_STRICT_LOCKING)) {
+		return NT_STATUS_OK;
+	}
+
+	return brlock_locktest(pvfs->brl_context,
+			    f->brl_handle,
+			    smbpid,
+			    offset, count, rw);
+}
+
+/* this state structure holds information about a lock we are waiting on */
+struct pvfs_pending_lock {
+	struct pvfs_pending_lock *next, *prev;
+	struct pvfs_state *pvfs;
+	union smb_lock *lck;
+	struct pvfs_file *f;
+	struct ntvfs_request *req;
+	int pending_lock;
+	struct pvfs_wait *wait_handle;
+	struct timeval end_time;
+};
+
+/*
+  a secondary attempt to setup a lock has failed - back out
+  the locks we did get and send an error
+*/
+static void pvfs_lock_async_failed(struct pvfs_state *pvfs,
+				   struct ntvfs_request *req,
+				   struct pvfs_file *f,
+				   struct smb_lock_entry *locks,
+				   int i,
+				   NTSTATUS status)
+{
+	/* undo the locks we just did */
+	for (i--;i>=0;i--) {
+		brlock_unlock(pvfs->brl_context,
+			   f->brl_handle,
+			   locks[i].pid,
+			   locks[i].offset,
+			   locks[i].count);
+		f->lock_count--;
+	}
+	req->async_states->status = status;
+	req->async_states->send_fn(req);
+}
+
+
+/*
+  called when we receive a pending lock notification. It means that
+  either our lock timed out or someone else has unlocked a overlapping
+  range, so we should try the lock again. Note that on timeout we
+  do retry the lock, giving it a last chance.
+*/
+static void pvfs_pending_lock_continue(void *private_data, enum pvfs_wait_notice reason)
+{
+	struct pvfs_pending_lock *pending = talloc_get_type(private_data,
+					    struct pvfs_pending_lock);
+	struct pvfs_state *pvfs = pending->pvfs;
+	struct pvfs_file *f = pending->f;
+	struct ntvfs_request *req = pending->req;
+	union smb_lock *lck = pending->lck;
+	struct smb_lock_entry *locks;
+	enum brl_type rw;
+	NTSTATUS status;
+	int i;
+	bool timed_out;
+
+	timed_out = (reason != PVFS_WAIT_EVENT);
+
+	locks = lck->lockx.in.locks + lck->lockx.in.ulock_cnt;
+
+	if (lck->lockx.in.mode & LOCKING_ANDX_SHARED_LOCK) {
+		rw = READ_LOCK;
+	} else {
+		rw = WRITE_LOCK;
+	}
+
+	DLIST_REMOVE(f->pending_list, pending);
+
+	/* we don't retry on a cancel */
+	if (reason == PVFS_WAIT_CANCEL) {
+		if (pvfs->ntvfs->ctx->protocol < PROTOCOL_SMB2_02) {
+			status = NT_STATUS_FILE_LOCK_CONFLICT;
+		} else {
+			status = NT_STATUS_CANCELLED;
+		}
+	} else {
+		/* 
+		 * here it's important to pass the pending pointer
+		 * because with this we'll get the correct error code
+		 * FILE_LOCK_CONFLICT in the error case
+		 */
+		status = brlock_lock(pvfs->brl_context,
+				  f->brl_handle,
+				  locks[pending->pending_lock].pid,
+				  locks[pending->pending_lock].offset,
+				  locks[pending->pending_lock].count,
+				  rw, pending);
+	}
+	if (NT_STATUS_IS_OK(status)) {
+		f->lock_count++;
+		timed_out = false;
+	}
+
+	/* if we have failed and timed out, or succeeded, then we
+	   don't need the pending lock any more */
+	if (NT_STATUS_IS_OK(status) || timed_out) {
+		NTSTATUS status2;
+		status2 = brlock_remove_pending(pvfs->brl_context, 
+					     f->brl_handle, pending);
+		if (!NT_STATUS_IS_OK(status2)) {
+			DEBUG(0,("pvfs_lock: failed to remove pending lock - %s\n", nt_errstr(status2)));
+		}
+		talloc_free(pending->wait_handle);
+	}
+
+	if (!NT_STATUS_IS_OK(status)) {
+		if (timed_out) {
+			/* no more chances */
+			pvfs_lock_async_failed(pvfs, req, f, locks, pending->pending_lock, status);
+			talloc_free(pending);
+		} else {
+			/* we can try again */
+			DLIST_ADD(f->pending_list, pending);
+		}
+		return;
+	}
+
+	/* if we haven't timed out yet, then we can do more pending locks */
+	if (rw == READ_LOCK) {
+		rw = PENDING_READ_LOCK;
+	} else {
+		rw = PENDING_WRITE_LOCK;
+	}
+
+	/* we've now got the pending lock. try and get the rest, which might
+	   lead to more pending locks */
+	for (i=pending->pending_lock+1;i<lck->lockx.in.lock_cnt;i++) {		
+		if (pending) {
+			pending->pending_lock = i;
+		}
+
+		status = brlock_lock(pvfs->brl_context,
+				  f->brl_handle,
+				  locks[i].pid,
+				  locks[i].offset,
+				  locks[i].count,
+				  rw, pending);
+		if (!NT_STATUS_IS_OK(status)) {
+			if (pending) {
+				/* a timed lock failed - setup a wait message to handle
+				   the pending lock notification or a timeout */
+				pending->wait_handle = pvfs_wait_message(pvfs, req, MSG_BRL_RETRY, 
+									 pending->end_time,
+									 pvfs_pending_lock_continue,
+									 pending);
+				if (pending->wait_handle == NULL) {
+					pvfs_lock_async_failed(pvfs, req, f, locks, i, NT_STATUS_NO_MEMORY);
+					talloc_free(pending);
+				} else {
+					talloc_steal(pending, pending->wait_handle);
+					DLIST_ADD(f->pending_list, pending);
+				}
+				return;
+			}
+			pvfs_lock_async_failed(pvfs, req, f, locks, i, status);
+			talloc_free(pending);
+			return;
+		}
+
+		f->lock_count++;
+	}
+
+	/* we've managed to get all the locks. Tell the client */
+	req->async_states->status = NT_STATUS_OK;
+	req->async_states->send_fn(req);
+	talloc_free(pending);
+}
+
+
+/*
+  called when we close a file that might have locks
+*/
+void pvfs_lock_close(struct pvfs_state *pvfs, struct pvfs_file *f)
+{
+	struct pvfs_pending_lock *p, *next;
+
+	if (f->lock_count || f->pending_list) {
+		DEBUG(5,("pvfs_lock: removing %.0f locks on close\n", 
+			 (double)f->lock_count));
+		brlock_close(f->pvfs->brl_context, f->brl_handle);
+		f->lock_count = 0;
+	}
+
+	/* reply to all the pending lock requests, telling them the 
+	   lock failed */
+	for (p=f->pending_list;p;p=next) {
+		next = p->next;
+		DLIST_REMOVE(f->pending_list, p);
+		p->req->async_states->status = NT_STATUS_RANGE_NOT_LOCKED;
+		p->req->async_states->send_fn(p->req);
+	}
+}
+
+
+/*
+  cancel a set of locks
+*/
+static NTSTATUS pvfs_lock_cancel(struct pvfs_state *pvfs, struct ntvfs_request *req, union smb_lock *lck,
+				 struct pvfs_file *f)
+{
+	struct pvfs_pending_lock *p;
+
+	for (p=f->pending_list;p;p=p->next) {
+		/* check if the lock request matches exactly - you can only cancel with exact matches */
+		if (p->lck->lockx.in.ulock_cnt == lck->lockx.in.ulock_cnt &&
+		    p->lck->lockx.in.lock_cnt  == lck->lockx.in.lock_cnt &&
+		    p->lck->lockx.in.file.ntvfs== lck->lockx.in.file.ntvfs &&
+		    p->lck->lockx.in.mode      == (lck->lockx.in.mode & ~LOCKING_ANDX_CANCEL_LOCK)) {
+			int i;
+
+			for (i=0;i<lck->lockx.in.ulock_cnt + lck->lockx.in.lock_cnt;i++) {
+				if (p->lck->lockx.in.locks[i].pid != lck->lockx.in.locks[i].pid ||
+				    p->lck->lockx.in.locks[i].offset != lck->lockx.in.locks[i].offset ||
+				    p->lck->lockx.in.locks[i].count != lck->lockx.in.locks[i].count) {
+					break;
+				}
+			}
+			if (i < lck->lockx.in.ulock_cnt) continue;
+
+			/* an exact match! we can cancel it, which is equivalent
+			   to triggering the timeout early */
+			pvfs_pending_lock_continue(p, PVFS_WAIT_TIMEOUT);
+			return NT_STATUS_OK;
+		}
+	}
+
+	return NT_STATUS_DOS(ERRDOS, ERRcancelviolation);
+}
+
+
+/*
+  lock or unlock a byte range
+*/
+NTSTATUS pvfs_lock(struct ntvfs_module_context *ntvfs,
+		   struct ntvfs_request *req, union smb_lock *lck)
+{
+	struct pvfs_state *pvfs = talloc_get_type(ntvfs->private_data,
+				  struct pvfs_state);
+	struct pvfs_file *f;
+	struct smb_lock_entry *locks;
+	int i;
+	enum brl_type rw;
+	struct pvfs_pending_lock *pending = NULL;
+	NTSTATUS status;
+
+	if (lck->generic.level != RAW_LOCK_GENERIC) {
+		return ntvfs_map_lock(ntvfs, req, lck);
+	}
+
+	if (lck->lockx.in.mode & LOCKING_ANDX_OPLOCK_RELEASE) {
+		return pvfs_oplock_release(ntvfs, req, lck);
+	}
+
+	f = pvfs_find_fd(pvfs, req, lck->lockx.in.file.ntvfs);
+	if (!f) {
+		return NT_STATUS_INVALID_HANDLE;
+	}
+
+	if (f->handle->fd == -1) {
+		return NT_STATUS_FILE_IS_A_DIRECTORY;
+	}
+
+	status = pvfs_break_level2_oplocks(f);
+	NT_STATUS_NOT_OK_RETURN(status);
+
+	if (lck->lockx.in.timeout != 0 && 
+	    (req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
+		pending = talloc(f, struct pvfs_pending_lock);
+		if (pending == NULL) {
+			return NT_STATUS_NO_MEMORY;
+		}
+
+		pending->pvfs = pvfs;
+		pending->lck = lck;
+		pending->f = f;
+		pending->req = req;
+
+		pending->end_time = 
+			timeval_current_ofs_msec(lck->lockx.in.timeout);
+	}
+
+	if (lck->lockx.in.mode & LOCKING_ANDX_SHARED_LOCK) {
+		rw = pending? PENDING_READ_LOCK : READ_LOCK;
+	} else {
+		rw = pending? PENDING_WRITE_LOCK : WRITE_LOCK;
+	}
+
+	if (lck->lockx.in.mode & LOCKING_ANDX_CANCEL_LOCK) {
+		talloc_free(pending);
+		return pvfs_lock_cancel(pvfs, req, lck, f);
+	}
+
+	if (lck->lockx.in.mode & LOCKING_ANDX_CHANGE_LOCKTYPE) {
+		/* this seems to not be supported by any windows server,
+		   or used by any clients */
+		talloc_free(pending);
+		return NT_STATUS_DOS(ERRDOS, ERRnoatomiclocks);
+	}
+
+	/* the unlocks happen first */
+	locks = lck->lockx.in.locks;
+
+	for (i=0;i<lck->lockx.in.ulock_cnt;i++) {
+		status = brlock_unlock(pvfs->brl_context,
+				    f->brl_handle,
+				    locks[i].pid,
+				    locks[i].offset,
+				    locks[i].count);
+		if (!NT_STATUS_IS_OK(status)) {
+			talloc_free(pending);
+			return status;
+		}
+		f->lock_count--;
+	}
+
+	locks += i;
+
+	for (i=0;i<lck->lockx.in.lock_cnt;i++) {
+		if (pending) {
+			pending->pending_lock = i;
+		}
+
+		status = brlock_lock(pvfs->brl_context,
+				  f->brl_handle,
+				  locks[i].pid,
+				  locks[i].offset,
+				  locks[i].count,
+				  rw, pending);
+		if (!NT_STATUS_IS_OK(status)) {
+			if (pending) {
+				/* a timed lock failed - setup a wait message to handle
+				   the pending lock notification or a timeout */
+				pending->wait_handle = pvfs_wait_message(pvfs, req, MSG_BRL_RETRY, 
+									 pending->end_time,
+									 pvfs_pending_lock_continue,
+									 pending);
+				if (pending->wait_handle == NULL) {
+					talloc_free(pending);
+					return NT_STATUS_NO_MEMORY;
+				}
+				talloc_steal(pending, pending->wait_handle);
+				DLIST_ADD(f->pending_list, pending);
+				return NT_STATUS_OK;
+			}
+
+			/* undo the locks we just did */
+			for (i--;i>=0;i--) {
+				brlock_unlock(pvfs->brl_context,
+					   f->brl_handle,
+					   locks[i].pid,
+					   locks[i].offset,
+					   locks[i].count);
+				f->lock_count--;
+			}
+			talloc_free(pending);
+			return status;
+		}
+		f->lock_count++;
+	}
+
+	talloc_free(pending);
+	return NT_STATUS_OK;
+}