linuxthreads: implement pthread_condattr_{s,g}etclock()

More applications are using pthread_condattr_setclock()/
pthread_condattr_getclock() in their code. Port these two
functions from NPTL over to be more compatible.

libpthread/linuxthreads/condvar.c

@@ -275,6 +275,7 @@ libpthread_hidden_def(pthread_cond_broadcast)
 
 int pthread_condattr_init(pthread_condattr_t *attr attribute_unused)
 {
+  memset (attr, '\0', sizeof (*attr));
   return 0;
 }
 libpthread_hidden_def(pthread_condattr_init)
@@ -302,3 +303,50 @@ int pthread_condattr_setpshared (pthread_condattr_t *attr attribute_unused, int
 
   return 0;
 }
+
+int pthread_condattr_getclock (const pthread_condattr_t *attr, clockid_t *clock_id)
+{
+  *clock_id = (((((const struct pthread_condattr *) attr)->value) >> 1)
+	       & ((1 << COND_NWAITERS_SHIFT) - 1));
+  return 0;
+}
+
+int pthread_condattr_setclock (pthread_condattr_t *attr, clockid_t clock_id)
+{
+  /* Only a few clocks are allowed.  CLOCK_REALTIME is always allowed.
+     CLOCK_MONOTONIC only if the kernel has the necessary support.  */
+  if (clock_id == CLOCK_MONOTONIC)
+    {
+#ifndef __ASSUME_POSIX_TIMERS
+# ifdef __NR_clock_getres
+      /* Check whether the clock is available.  */
+      static int avail;
+
+      if (avail == 0)
+	{
+	  struct timespec ts;
+
+	  INTERNAL_SYSCALL_DECL (err);
+	  int val;
+	  val = INTERNAL_SYSCALL (clock_getres, err, 2, CLOCK_MONOTONIC, &ts);
+	  avail = INTERNAL_SYSCALL_ERROR_P (val, err) ? -1 : 1;
+	}
+
+      if (avail < 0)
+# endif
+	/* Not available.  */
+	return EINVAL;
+#endif
+    }
+  else if (clock_id != CLOCK_REALTIME)
+    /* If more clocks are allowed some day the storing of the clock ID
+       in the pthread_cond_t structure needs to be adjusted.  */
+    return EINVAL;
+
+  int *valuep = &((struct pthread_condattr *) attr)->value;
+
+  *valuep = ((*valuep & ~(((1 << COND_NWAITERS_SHIFT) - 1) << 1))
+	     | (clock_id << 1));
+
+  return 0;
+}

libpthread/linuxthreads/internals.h

@@ -51,6 +51,25 @@
 # define THREAD_SETMEM_NC(descr, member, value) descr->member = (value)
 #endif
 
+/* Conditional variable attribute data structure.  */
+struct pthread_condattr
+{
+  /* Combination of values:
+
+     Bit 0  : flag whether coditional variable will be shareable between
+	      processes.
+
+     Bit 1-7: clock ID.  */
+  int value;
+};
+
+/* The __NWAITERS field is used as a counter and to house the number
+   of bits for other purposes.  COND_CLOCK_BITS is the number
+   of bits needed to represent the ID of the clock.  COND_NWAITERS_SHIFT
+   is the number of bits reserved for other purposes like the clock.  */
+#define COND_CLOCK_BITS		1
+#define COND_NWAITERS_SHIFT	1
+
 /* Arguments passed to thread creation routine */
 
 struct pthread_start_args {

libpthread/linuxthreads/sysdeps/pthread/bits/pthreadtypes.h

@@ -25,6 +25,8 @@
 #define __need_schedparam
 #include <bits/sched.h>
 
+#define __SIZEOF_PTHREAD_CONDATTR_T 4
+
 /* Fast locks (not abstract because mutexes and conditions aren't abstract). */
 struct _pthread_fastlock
 {
@@ -63,12 +65,13 @@ typedef struct
 } pthread_cond_t;
 
 
-/* Attribute for conditionally variables.  */
-typedef struct
+typedef union
 {
-  int __dummy;
+  char __size[__SIZEOF_PTHREAD_CONDATTR_T];
+  int __align;
 } pthread_condattr_t;
 
+
 /* Keys for thread-specific data */
 typedef unsigned int pthread_key_t;
 

libpthread/linuxthreads/sysdeps/pthread/pthread.h

@@ -455,6 +455,18 @@ extern int pthread_condattr_getpshared (const pthread_condattr_t *
 extern int pthread_condattr_setpshared (pthread_condattr_t *__attr,
 					int __pshared) __THROW;
 
+#ifdef __USE_XOPEN2K
+/* Get the clock selected for the condition variable attribute ATTR.  */
+extern int pthread_condattr_getclock (const pthread_condattr_t *
+				      __restrict __attr,
+				      __clockid_t *__restrict __clock_id)
+     __THROW __nonnull ((1, 2));
+
+/* Set the clock selected for the condition variable attribute ATTR.  */
+extern int pthread_condattr_setclock (pthread_condattr_t *__attr,
+				      __clockid_t __clock_id)
+     __THROW __nonnull ((1));
+#endif
 
 #if defined __USE_UNIX98 || defined __USE_XOPEN2K
 /* Functions for handling read-write locks.  */