net/third_party/nss/ssl/sslmutex.h

   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 /* $Id: sslmutex.h,v 1.14 2012/04/25 14:50:12 gerv%gerv.net Exp $ */
   5 #ifndef __SSLMUTEX_H_
   6 #define __SSLMUTEX_H_ 1
   7
   8 /* What SSL really wants is portable process-shared unnamed mutexes in
   9  * shared memory, that have the property that if the process that holds
  10  * them dies, they are released automatically, and that (unlike fcntl
  11  * record locking) lock to the thread, not to the process.
  12  * NSPR doesn't provide that.
  13  * Windows has mutexes that meet that description, but they're not portable.
  14  * POSIX mutexes are not automatically released when the holder dies,
  15  * and other processes/threads cannot release the mutex on behalf of the
  16  * dead holder.
  17  * POSIX semaphores can be used to accomplish this on systems that implement
  18  * process-shared unnamed POSIX semaphores, because a watchdog thread can
  19  * discover and release semaphores that were held by a dead process.
  20  * On systems that do not support process-shared POSIX unnamed semaphores,
  21  * they can be emulated using pipes.
  22  * The performance cost of doing that is not yet measured.
  23  *
  24  * So, this API looks a lot like POSIX pthread mutexes.
  25  */
  26
  27 #include "prtypes.h"
  28 #include "prlock.h"
  29
  30 #if defined(NETBSD)
  31 #include <sys/param.h> /* for __NetBSD_Version__ */
  32 #endif
  33
  34 #if defined(WIN32)
  35
  36 #include <wtypes.h>
  37
  38 typedef struct
  39 {
  40     PRBool isMultiProcess;
  41 #ifdef WINNT
  42     /* on WINNT we need both the PRLock and the Win32 mutex for fibers */
  43     struct {
  44 #else
  45     union {
  46 #endif
  47         PRLock* sslLock;
  48         HANDLE sslMutx;
  49     } u;
  50 } sslMutex;
  51
  52 typedef int    sslPID;
  53
  54 #elif defined(LINUX) || defined(AIX) || defined(BEOS) || defined(BSDI) || (defined(NETBSD) && __NetBSD_Version__ < 500000000) || defined(OPENBSD)
  55
  56 #include <sys/types.h>
  57 #include "prtypes.h"
  58
  59 typedef struct {
  60     PRBool isMultiProcess;
  61     union {
  62         PRLock* sslLock;
  63         struct {
  64             int      mPipes[3];
  65             PRInt32  nWaiters;
  66         } pipeStr;
  67     } u;
  68 } sslMutex;
  69 typedef pid_t sslPID;
  70
  71 #elif defined(XP_UNIX) /* other types of Unix */
  72
  73 #include <sys/types.h>  /* for pid_t */
  74 #include <semaphore.h>  /* for sem_t, and sem_* functions */
  75
  76 typedef struct
  77 {
  78     PRBool isMultiProcess;
  79     union {
  80         PRLock* sslLock;
  81         sem_t  sem;
  82     } u;
  83 } sslMutex;
  84
  85 typedef pid_t sslPID;
  86
  87 #else
  88
  89 /* what platform is this ?? */
  90
  91 typedef struct {
  92     PRBool isMultiProcess;
  93     union {
  94         PRLock* sslLock;
  95         /* include cross-process locking mechanism here */
  96     } u;
  97 } sslMutex;
  98
  99 typedef int sslPID;
 100
 101 #endif
 102
 103 #include "seccomon.h"
 104
 105 SEC_BEGIN_PROTOS
 106
 107 extern SECStatus sslMutex_Init(sslMutex *sem, int shared);
 108
 109 /* If processLocal is set to true, then just free resources which are *only* associated
 110  * with the current process. Leave any shared resources (including the state of
 111  * shared memory) intact. */
 112 extern SECStatus sslMutex_Destroy(sslMutex *sem, PRBool processLocal);
 113
 114 extern SECStatus sslMutex_Unlock(sslMutex *sem);
 115
 116 extern SECStatus sslMutex_Lock(sslMutex *sem);
 117
 118 #ifdef WINNT
 119
 120 extern SECStatus sslMutex_2LevelInit(sslMutex *sem);
 121
 122 #endif
 123
 124 SEC_END_PROTOS
 125
 126 #endif