Add implementation of pthread_rwlock based on NaCl futexs

src/untrusted/pthread/pthread.h

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /** @file
  * Defines the API in the
  * <a href="group___pthread.html">Pthread library</a>
  *
@@ skipping 111 matching lines @@
 } pthread_cond_t;
 
 /**
  * A structure representing condition variable attributes. Currently
  * Native Client condition variables have no attributes.
  */
 typedef struct {
   int dummy; /**< Reserved; condition variables don't have attributes */
 } pthread_condattr_t;
 
+/**
+ * A structure representing rwlock attributes. It should be considered an
+ * opaque record.
+ */
+typedef int32_t pthread_rwlockattr_t;
+
+/**
+ * A structure representing a rwlock. It should be considered an
+ * opaque record; the names of the fields can change anytime.
+ */
+typedef struct {
+  volatile int32_t state;  /* 0=unlock, -1=writer lock, +n=reader lock */
+  struct __nc_basic_thread_data *volatile writer_thread_id;
+  volatile int32_t pending_readers;
+  volatile int32_t pending_writers;
+  pthread_rwlockattr_t attr;
+} pthread_rwlock_t;
+
 /** A value that represents an uninitialized handle. */
 #define NC_INVALID_HANDLE -1
 
 /** Maximum valid thread ID value. */
 #define MAX_THREAD_ID (0xfffffffe)
 
 /** Illegal thread ID value. */
 #define NACL_PTHREAD_ILLEGAL_THREAD_ID ((pthread_t) 0)
 
 /** Statically initializes a pthread_mutex_t representing a recursive mutex. */
 #define PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP \
     {0, 1, NACL_PTHREAD_ILLEGAL_THREAD_ID, 0, NC_INVALID_HANDLE}
 /** Statically initializes a pthread_mutex_t representing a fast mutex. */
 #define PTHREAD_MUTEX_INITIALIZER \
     {0, 0, NACL_PTHREAD_ILLEGAL_THREAD_ID, 0, NC_INVALID_HANDLE}
 /**
  * Statically initializes a pthread_mutex_t representing an
  * error-checking mutex.
  */
 #define PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP \
     {0, 2, NACL_PTHREAD_ILLEGAL_THREAD_ID, 0, NC_INVALID_HANDLE}
 /** Statically initializes a condition variable (pthread_cond_t). */
 #define PTHREAD_COND_INITIALIZER {0, NC_INVALID_HANDLE}
 
-
+#define PTHREAD_PROCESS_PRIVATE  0
+#define PTHREAD_PROCESS_SHARED   1
 
 /* Functions for mutex handling.  */
 
 /** @nqPosix
  * Initializes a mutex using attributes in mutex_attr, or using the
  * default values if the latter is NULL.
  *
  * @linkPthread
  *
  * @param mutex The address of the mutex structure to be initialized.
@@ skipping 202 matching lines @@
 int pthread_cond_timedwait_rel(pthread_cond_t *cond,
                                pthread_mutex_t *mutex,
                                const struct timespec *reltime);
 
 /**
  * Defined for POSIX compatibility; pthread_cond_timedwait() is actually
  * a macro calling pthread_cond_timedwait_abs().
  */
 #define pthread_cond_timedwait pthread_cond_timedwait_abs
 
+/* Functions for rwlock handling.  */
+
+int pthread_rwlockattr_init(pthread_rwlockattr_t *attr);
+int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *attr,
+                                  int *pshared);
+int pthread_rwlockattr_setpshared(pthread_rwlockattr_t *attr, int pshared);
+int pthread_rwlockattr_destroy(pthread_rwlockattr_t *attr);
+
+int pthread_rwlock_init(pthread_rwlock_t *rwlock,
+                        const pthread_rwlockattr_t *attr);
+
+int pthread_rwlock_rdlock(pthread_rwlock_t *rwlock);
+int pthread_rwlock_tryrdlock(pthread_rwlock_t *rwlock);
+int pthread_rwlock_timedrdlock(pthread_rwlock_t *rwlock,
+                               const struct timespec *abstime);
+
+
+int pthread_rwlock_wrlock(pthread_rwlock_t *rwlock);
+int pthread_rwlock_trywrlock(pthread_rwlock_t *rwlock);
+int pthread_rwlock_timedwrlock(pthread_rwlock_t *rwlock,
+                               const struct timespec *abstime);
+
+int pthread_rwlock_unlock(pthread_rwlock_t *rwlock);
+int pthread_rwlock_destroy(pthread_rwlock_t *rwlock);
 
 /* Threads */
 /** Thread entry function type. */
 typedef void *(*nc_thread_function)(void *p);
 /** Thread identifier type. */
 typedef struct __nc_basic_thread_data *pthread_t;
 
 /** A structure representing thread attributes. */
 typedef struct {
   int joinable; /**< 1 if the thread is joinable, 0 otherwise */
@@ skipping 321 matching lines @@
 
 /**
 * @} End of PTHREAD group
 */
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif  /* pthread.h */