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 #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