text: /* This Source Code Form is subject to the terms of the Mozilla Public
   * License, v. 2.0. If a copy of the MPL was not distributed with this
   * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  #ifndef __SSLMUTEX_H_
  #define __SSLMUTEX_H_ 1
  
  /* What SSL really wants is portable process-shared unnamed mutexes in 
   * shared memory, that have the property that if the process that holds
   * them dies, they are released automatically, and that (unlike fcntl 
   * record locking) lock to the thread, not to the process.  
   * NSPR doesn't provide that.  
   * Windows has mutexes that meet that description, but they're not portable.  
   * POSIX mutexes are not automatically released when the holder dies, 
   * and other processes/threads cannot release the mutex on behalf of the 
   * dead holder.  
   * POSIX semaphores can be used to accomplish this on systems that implement 
   * process-shared unnamed POSIX semaphores, because a watchdog thread can 
   * discover and release semaphores that were held by a dead process.  
   * On systems that do not support process-shared POSIX unnamed semaphores, 
   * they can be emulated using pipes.  
   * The performance cost of doing that is not yet measured.
   *
   * So, this API looks a lot like POSIX pthread mutexes.
   */
  
  #include "prtypes.h"
  #include "prlock.h"
  
  #if defined(NETBSD)
  #include <sys/param.h> /* for __NetBSD_Version__ */
  #endif
  
  #if defined(WIN32)
  
  #include <wtypes.h>
  
  typedef struct 
  {
      PRBool isMultiProcess;
  #ifdef WINNT
      /* on WINNT we need both the PRLock and the Win32 mutex for fibers */
      struct {
  #else
      union {
  #endif
          PRLock* sslLock;
          HANDLE sslMutx;
      } u;
  } sslMutex;
  
  typedef int    sslPID;
  
  #elif defined(LINUX) || defined(AIX) || defined(BEOS) || defined(BSDI) || (defined(NETBSD) && __NetBSD_Version__ < 500000000) || defined(OPENBSD)
  
  #include <sys/types.h>
  #include "prtypes.h"
  
  typedef struct { 
      PRBool isMultiProcess;
      union {
          PRLock* sslLock;
          struct {
              int      mPipes[3]; 
              PRInt32  nWaiters;
          } pipeStr;
      } u;
  } sslMutex;
  typedef pid_t sslPID;
  
  #elif defined(XP_UNIX) /* other types of Unix */
  
  #include <sys/types.h>	/* for pid_t */
  #include <semaphore.h>  /* for sem_t, and sem_* functions */
  
  typedef struct
  {
      PRBool isMultiProcess;
      union {
          PRLock* sslLock;
          sem_t  sem;
      } u;
  } sslMutex;
  
  typedef pid_t sslPID;
  
  #else
  
  /* what platform is this ?? */
  
  typedef struct { 
      PRBool isMultiProcess;
      union {
          PRLock* sslLock;
          /* include cross-process locking mechanism here */
      } u;
  } sslMutex;
  
  typedef int sslPID;
  
  #endif
  
  #include "seccomon.h"
  
  SEC_BEGIN_PROTOS
  
  extern SECStatus sslMutex_Init(sslMutex *sem, int shared);
  
  /* If processLocal is set to true, then just free resources which are *only* associated
   * with the current process. Leave any shared resources (including the state of 
   * shared memory) intact. */
  extern SECStatus sslMutex_Destroy(sslMutex *sem, PRBool processLocal);
  
  extern SECStatus sslMutex_Unlock(sslMutex *sem);
  
  extern SECStatus sslMutex_Lock(sslMutex *sem);
  
  #ifdef WINNT
  
  extern SECStatus sslMutex_2LevelInit(sslMutex *sem);
  
  #endif
  
  SEC_END_PROTOS
  
  #endif
  