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      1 /* This Source Code Form is subject to the terms of the Mozilla Public
      2  * License, v. 2.0. If a copy of the MPL was not distributed with this
      3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      4 #ifndef __SSLMUTEX_H_
      5 #define __SSLMUTEX_H_ 1
      6 
      7 /* What SSL really wants is portable process-shared unnamed mutexes in
      8  * shared memory, that have the property that if the process that holds
      9  * them dies, they are released automatically, and that (unlike fcntl
     10  * record locking) lock to the thread, not to the process.
     11  * NSPR doesn't provide that.
     12  * Windows has mutexes that meet that description, but they're not portable.
     13  * POSIX mutexes are not automatically released when the holder dies,
     14  * and other processes/threads cannot release the mutex on behalf of the
     15  * dead holder.
     16  * POSIX semaphores can be used to accomplish this on systems that implement
     17  * process-shared unnamed POSIX semaphores, because a watchdog thread can
     18  * discover and release semaphores that were held by a dead process.
     19  * On systems that do not support process-shared POSIX unnamed semaphores,
     20  * they can be emulated using pipes.
     21  * The performance cost of doing that is not yet measured.
     22  *
     23  * So, this API looks a lot like POSIX pthread mutexes.
     24  */
     25 
     26 #include "prtypes.h"
     27 #include "prlock.h"
     28 
     29 #if defined(NETBSD)
     30 #include <sys/param.h> /* for __NetBSD_Version__ */
     31 #endif
     32 
     33 #if defined(WIN32)
     34 
     35 #include <wtypes.h>
     36 
     37 typedef struct
     38 {
     39     PRBool isMultiProcess;
     40 #ifdef WINNT
     41     /* on WINNT we need both the PRLock and the Win32 mutex for fibers */
     42     struct {
     43 #else
     44     union {
     45 #endif
     46         PRLock* sslLock;
     47         HANDLE sslMutx;
     48     } u;
     49 } sslMutex;
     50 
     51 typedef int    sslPID;
     52 
     53 #elif defined(LINUX) || defined(AIX) || defined(BEOS) || defined(BSDI) || (defined(NETBSD) && __NetBSD_Version__ < 500000000) || defined(OPENBSD)
     54 
     55 #include <sys/types.h>
     56 #include "prtypes.h"
     57 
     58 typedef struct {
     59     PRBool isMultiProcess;
     60     union {
     61         PRLock* sslLock;
     62         struct {
     63             int      mPipes[3];
     64             PRInt32  nWaiters;
     65         } pipeStr;
     66     } u;
     67 } sslMutex;
     68 typedef pid_t sslPID;
     69 
     70 #elif defined(XP_UNIX) /* other types of Unix */
     71 
     72 #include <sys/types.h>	/* for pid_t */
     73 #include <semaphore.h>  /* for sem_t, and sem_* functions */
     74 
     75 typedef struct
     76 {
     77     PRBool isMultiProcess;
     78     union {
     79         PRLock* sslLock;
     80         sem_t  sem;
     81     } u;
     82 } sslMutex;
     83 
     84 typedef pid_t sslPID;
     85 
     86 #else
     87 
     88 /* what platform is this ?? */
     89 
     90 typedef struct {
     91     PRBool isMultiProcess;
     92     union {
     93         PRLock* sslLock;
     94         /* include cross-process locking mechanism here */
     95     } u;
     96 } sslMutex;
     97 
     98 typedef int sslPID;
     99 
    100 #endif
    101 
    102 #include "seccomon.h"
    103 
    104 SEC_BEGIN_PROTOS
    105 
    106 extern SECStatus sslMutex_Init(sslMutex *sem, int shared);
    107 
    108 /* If processLocal is set to true, then just free resources which are *only* associated
    109  * with the current process. Leave any shared resources (including the state of
    110  * shared memory) intact. */
    111 extern SECStatus sslMutex_Destroy(sslMutex *sem, PRBool processLocal);
    112 
    113 extern SECStatus sslMutex_Unlock(sslMutex *sem);
    114 
    115 extern SECStatus sslMutex_Lock(sslMutex *sem);
    116 
    117 #ifdef WINNT
    118 
    119 extern SECStatus sslMutex_2LevelInit(sslMutex *sem);
    120 
    121 #endif
    122 
    123 SEC_END_PROTOS
    124 
    125 #endif
    126