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/** BEGIN COPYRIGHT BLOCK
* Copyright 2001 Sun Microsystems, Inc.
* Portions copyright 1999, 2001-2003 Netscape Communications Corporation.
* All rights reserved.
* END COPYRIGHT BLOCK **/
/*
* fsmutex: Mutexes that are filesystem-based so they're available from more
* than one process and address space
*
* Rob McCool
*/
#ifndef FSMUTEX_H
#define FSMUTEX_H
#include "netsite.h"
typedef void * FSMUTEX;
/* ------------------------------ Prototypes ------------------------------ */
NSPR_BEGIN_EXTERN_C
/*
Flags to fsmutex_init.
FSMUTEX_VISIBLE makes a filesystem mutex which can be opened by other
programs or processes.
FSMUTEX_NEEDCRIT specifies that the fsmutex_lock and fsmutex_unlock
functions should also use a critical section to ensure that more than
one thread does not acquire the mutex at a time. If this flag is not
specified, it is up to the caller to ensure that only thread within a
process tries to acquire the lock at any given time.
*/
#define FSMUTEX_VISIBLE 0x01
#define FSMUTEX_NEEDCRIT 0x02
/*
fsmutex_init creates a new filesystem-based mutex. The resulting mutex
is part of the filesystem. The name and number parameters are used to
create a name for the mutex. If the FSMUTEX_VISIBLE flag is specified,
the mutex will be left in the filesystem for other programs and processes
to access. If a mutex with the given name/number combination already
exists, the calling process is allowed access to it. If the mutex does
not already exist, the mutex is created.
Returns NULL on failure, a void pointer to a fsmutex structure otherwise.
This fsmutex structure is local to the current process.
*/
NSAPI_PUBLIC FSMUTEX fsmutex_init(char *name, int number, int flags);
/*
Sets the ownership of the underlying filesystem object to the given
uid and gid. Only effective if the server is running as root.
*/
#ifdef XP_UNIX
#include <unistd.h>
#ifdef __sony
#include <sys/types.h>
#endif
NSAPI_PUBLIC void fsmutex_setowner(FSMUTEX fsm, uid_t uid, gid_t gid);
#endif
/*
fsmutex_terminate deletes a filesystem-based mutex. A mutex will only
be deleted when every process which has an open pointer to the mutex
calls this function.
*/
NSAPI_PUBLIC void fsmutex_terminate(FSMUTEX id);
/*
fsmutex_lock attempts to acquire the given filesystem-based mutex. If
another process is holding the mutex, or if the FSMUTEX_NEEDCRIT flag
was passed to fsmutex_init and another thread in the current process is
holding the mutex, then the calling thread will block until the mutex
is available.
*/
NSAPI_PUBLIC void fsmutex_lock(FSMUTEX id);
/*
fsmutex_unlock releases a filesystem-based mutex previously acquired
by fsmutex_lock.
*/
NSAPI_PUBLIC void fsmutex_unlock(FSMUTEX id);
NSPR_END_EXTERN_C
#endif
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