src/lib/lock/compat_mutex.h

   1 /* Copyright (c) 2003-2004, Roger Dingledine
   2  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   3  * Copyright (c) 2007-2019, The Tor Project, Inc. */
   4 /* See LICENSE for licensing information */
   5
   6 /**
   7  * \file compat_mutex.h
   8  *
   9  * \brief Header for compat_mutex.c
  10  **/
  11
  12 #ifndef TOR_COMPAT_MUTEX_H
  13 #define TOR_COMPAT_MUTEX_H
  14
  15 #include "orconfig.h"
  16 #include "lib/cc/torint.h"
  17 #include "lib/malloc/malloc.h"
  18
  19 #if defined(HAVE_PTHREAD_H) && !defined(_WIN32)
  20 #include <pthread.h>
  21 #endif
  22
  23 #if defined(_WIN32)
  24 #include <windows.h>
  25 #endif
  26
  27 #if defined(_WIN32)
  28 #define USE_WIN32_THREADS
  29 #elif defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_CREATE)
  30 #define USE_PTHREADS
  31 #else
  32 #error "No threading system was found"
  33 #endif /* defined(_WIN32) || ... */
  34
  35 /* Because we use threads instead of processes on most platforms (Windows,
  36  * Linux, etc), we need locking for them.  On platforms with poor thread
  37  * support or broken gethostbyname_r, these functions are no-ops. */
  38
  39 /** A generic lock structure for multithreaded builds. */
  40 typedef struct tor_mutex_t {
  41 #if defined(USE_WIN32_THREADS)
  42   /** Windows-only: on windows, we implement locks with CRITICAL_SECTIONS. */
  43   CRITICAL_SECTION mutex;
  44 #elif defined(USE_PTHREADS)
  45   /** Pthreads-only: with pthreads, we implement locks with
  46    * pthread_mutex_t. */
  47   pthread_mutex_t mutex;
  48 #else
  49   /** No-threads only: Dummy variable so that tor_mutex_t takes up space. */
  50   int _unused;
  51 #endif /* defined(USE_WIN32_MUTEX) || ... */
  52 } tor_mutex_t;
  53
  54 tor_mutex_t *tor_mutex_new(void);
  55 tor_mutex_t *tor_mutex_new_nonrecursive(void);
  56 void tor_mutex_init(tor_mutex_t *m);
  57 void tor_mutex_init_nonrecursive(tor_mutex_t *m);
  58 void tor_mutex_acquire(tor_mutex_t *m);
  59 void tor_mutex_release(tor_mutex_t *m);
  60 void tor_mutex_free_(tor_mutex_t *m);
  61 #define tor_mutex_free(m) FREE_AND_NULL(tor_mutex_t, tor_mutex_free_, (m))
  62 void tor_mutex_uninit(tor_mutex_t *m);
  63
  64 void tor_locking_init(void);
  65
  66 #endif /* !defined(TOR_COMPAT_MUTEX_H) */