Implement pthread_rwlock functions for NaCl newlib.

src/untrusted/pthread/pthread.h

Index: src/untrusted/pthread/pthread.h
diff --git a/src/untrusted/pthread/pthread.h b/src/untrusted/pthread/pthread.h
index 00eee7ba8d13f7d5eb8e557a29132f482e81471e..11eeaf81a78e68141dcc697c08a69ea34124d45b 100644
--- a/src/untrusted/pthread/pthread.h
+++ b/src/untrusted/pthread/pthread.h
@@ -129,6 +129,27 @@ typedef struct {
   int dummy; /**< Reserved; condition variables don't have attributes */
 } pthread_condattr_t;
 
+/**
+ * A structure representing a rwlock. It should be considered an
+ * opaque record; the names of the fields can change anytime.
+ */
+typedef struct {
+  pthread_mutex_t mutex; /* mutex for all values in the structure */
+  int reader_count;
+  int writers_waiting;
+  struct __nc_basic_thread_data *writer_thread_id;
+  pthread_cond_t read_possible;
+  pthread_cond_t write_possible;
+} pthread_rwlock_t;
+
+/**
+ * A structure representing rwlock attributes. It should be considered an
+ * opaque record.
+ */
+typedef struct {
+  int type;
+} pthread_rwlockattr_t;
+
 /** A value that represents an uninitialized handle. */
 #define NC_INVALID_HANDLE -1
 
@@ -153,6 +174,8 @@ typedef struct {
 /** 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.  */
@@ -353,7 +376,7 @@ int pthread_cond_timedwait_abs(pthread_cond_t *cond,
                                pthread_mutex_t *mutex,
                                const struct timespec *abstime);
 
- /** @nqPosix
+/** @nqPosix
 * Waits for condition variable cond to be signaled or broadcast; wait time is
 * limited by reltime.
 *
@@ -376,6 +399,31 @@ int pthread_cond_timedwait_rel(pthread_cond_t *cond,
  */
 #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,

[Mark Seaborn, 2015/01/05 16:58:53]

There's no implementation of get/setpshared in this change.  Can you make the .h
and .c files match up, please?

[Sam Clegg, 2015/01/06 19:06:25]

Done.  Add added test code.

+                                  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. */
@@ -499,6 +547,7 @@ extern int pthread_kill(pthread_t thread_id,
                         int sig);
 
 /* Functions for handling thread attributes.  */
+
 /** @nqPosix
 * Initializes thread attributes structure attr with default attributes
 * (detachstate is PTHREAD_CREATE_JOINABLE).