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sslmutex.h (3307B)

      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    PRBool isMultiProcess;
     39 #ifdef WINNT
     40    /* on WINNT we need both the PRLock and the Win32 mutex for fibers */
     41    struct {
     42 #else
     43    union {
     44 #endif
     45        PRLock *sslLock;
     46        HANDLE sslMutx;
     47    } u;
     48 } sslMutex;
     49 
     50 typedef int sslPID;
     51 
     52 #elif defined(LINUX) || defined(AIX) || defined(BSDI) || \
     53    (defined(NETBSD) && __NetBSD_Version__ < 500000000) || defined(OPENBSD) || defined(__GLIBC__)
     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 /* other types of unix, except OS X */
     71 #elif defined(XP_UNIX) && !defined(DARWIN)
     72 
     73 #include <sys/types.h> /* for pid_t */
     74 #include <semaphore.h> /* for sem_t, and sem_* functions */
     75 
     76 typedef struct {
     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 /* no support for cross-process locking */
     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 #ifdef DARWIN
     99 typedef pid_t sslPID;
    100 #else
    101 typedef int sslPID;
    102 #endif
    103 
    104 #endif
    105 
    106 #include "seccomon.h"
    107 
    108 SEC_BEGIN_PROTOS
    109 
    110 extern SECStatus sslMutex_Init(sslMutex *sem, int shared);
    111 
    112 /* If processLocal is set to true, then just free resources which are *only* associated
    113 * with the current process. Leave any shared resources (including the state of
    114 * shared memory) intact. */
    115 extern SECStatus sslMutex_Destroy(sslMutex *sem, PRBool processLocal);
    116 
    117 extern SECStatus sslMutex_Unlock(sslMutex *sem);
    118 
    119 extern SECStatus sslMutex_Lock(sslMutex *sem);
    120 
    121 #ifdef WINNT
    122 
    123 extern SECStatus sslMutex_2LevelInit(sslMutex *sem);
    124 
    125 #endif
    126 
    127 SEC_END_PROTOS
    128 
    129 #endif