60 lines
1.9 KiB
C
60 lines
1.9 KiB
C
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/**
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* xrdp: A Remote Desktop Protocol server.
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*
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* Copyright (C) 2022 Matt Burt, all xrdp contributors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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*
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* @file lock_uds.h
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* @brief Providing a locking facility for Unix Domain Sockets
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* @author Matt Burt
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*
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* It is difficult for a server to determine whether a socket it wishes
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* to listen on is already active or not. The purpose of this module is to
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* provide a locking facility which can be used as a proxy for this.
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*/
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#ifndef LOCK_UDS_H
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#define LOCK_UDS_H
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struct lock_uds;
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/**
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* Take out a lock for the specified Unix Domain socket
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* @param sockname Name of socket. Must start with a '/'
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* @return A struct lock_uds instance if the lock was successfully acquired.
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*
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* A NULL return may indicate a lack of memory, or that another
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* process has the lock.
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*
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* A file is created in the same directory as the socket. The name
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* of the file is ".${basename}.lock", where basename is the base name
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* of the socket. THE file is removed when the lock is relinquished. */
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struct lock_uds *
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lock_uds(const char *sockname);
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/**
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* Relinquish a lock on the specified Unix Domain Socket.
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* @param lock to relinquish
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*
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* If the process which has originally taken out the lock forks, this
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* routine should be called from the child process to prevent the lock
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* inadvertently being passed to the child. */
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void
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unlock_uds(struct lock_uds *lock);
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#endif // LOCK_UDS_H
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