* k5-thread.h: New file

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@16148 dc483132-0cff-0310-8789-dd5450dbe970

2 files changed, 151 insertions, 0 deletions

diff --git a/src/include/ChangeLog b/src/include/ChangeLog
index 3d703d42c7..12abf8a755 100644
--- a/src/include/ChangeLog
+++ b/src/include/ChangeLog
@@ -1,3 +1,7 @@
+2004-03-05  Ken Raeburn  <raeburn@mit.edu>
+
+	* k5-thread.h: New file.
+
 2004-02-26  Jeffrey Altman <jaltman@mit.edu>
 
     * k5-int.h: change prototype declarations necessary to support
diff --git a/src/include/k5-thread.h b/src/include/k5-thread.h
new file mode 100644
index 0000000000..cde3655ecc
--- /dev/null
+++ b/src/include/k5-thread.h
@@ -0,0 +1,147 @@
+/* Copyright 2004 Massachusetts Institute of Technology.
+   All Rights Reserved.  */
+
+#ifndef K5_MUTEX_INITIALIZER /* handle multiple inclusion */
+
+#include "autoconf.h"
+
+/* Interface (tentative):
+
+   k5_mutex_t foo_mutex = K5_MUTEX_INITIALIZER;
+   int k5_mutex_init(k5_mutex_t *);
+   int k5_mutex_destroy(k5_mutex_t *);
+   int k5_mutex_lock(k5_mutex_t *);
+   int k5_mutex_unlock(k5_mutex_t *);
+
+   k5_key_t key;
+   int k5_key_create(k5_key_t *, void (*destructor)(void *));
+   void *k5_getspecific(k5_key_t);
+   int k5_setspecific(k5_key_t, const void *);
+   ... stuff to signal library termination ...
+
+   More to be added, probably.  */
+
+#ifndef HAVE_PTHREAD_H
+# undef ENABLE_THREADS
+#endif
+
+#define DEBUG_THREADS
+
+#include <assert.h>
+typedef struct {
+    /* We've got some bits to spare; using more than one bit decreases
+       the likelihood that random storage will contain the right
+       values.  */
+    unsigned int initialized : 3;
+    unsigned int locked : 3;
+    /* No source file in this tree gets anywhere near 32K lines.  */
+    short lineno;
+    const char *filename;
+} k5_mutex_debug_info;
+#define K5_MUTEX_DEBUG_INITIALIZER	{ 1, 0, 0, 0 }
+#define K5_MUTEX_DEBUG_LOCKED		4
+#define K5_MUTEX_DEBUG_UNLOCKED		3
+#define k5_mutex_debug_init(M)			\
+	((M)->initialized = 1,			\
+	 (M)->locked = K5_MUTEX_DEBUG_UNLOCKED,	\
+	 (M)->lineno = 0, (M)->filename = 0, 0)
+#define k5_mutex_debug_destroy(M)				\
+	(assert((M)->initialized == 1				\
+		&& (M)->locked == K5_MUTEX_DEBUG_UNLOCKED),	\
+	 (M)->initialized = 0)
+#define k5_mutex_debug_lock(M)					\
+	(assert((M)->initialized == 1				\
+		&& (M)->locked == K5_MUTEX_DEBUG_UNLOCKED),	\
+	 (M)->locked = K5_MUTEX_DEBUG_LOCKED,			\
+	 (M)->lineno = __LINE__, (M)->filename = __FILE__, 0)
+#define k5_mutex_debug_unlock(M)				\
+	(assert((M)->initialized == 1				\
+		&& (M)->locked == K5_MUTEX_DEBUG_LOCKED),	\
+	 (M)->locked = K5_MUTEX_DEBUG_UNLOCKED,			\
+	 (M)->lineno = __LINE__, (M)->filename = __FILE__, 0)
+
+#ifdef ENABLE_THREADS
+
+#include <pthread.h>
+
+/* To do:  Weak symbol support.  Windows threads.
+
+   Mutex initialization may need to be re-thought if we find we want
+   any non-default attributes, like priority inheritance.  */
+
+#ifndef DEBUG_THREADS
+
+typedef pthread_mutex_t k5_mutex_t;
+#define K5_MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
+
+#define k5_mutex_init(M)	pthread_mutex_init(M, 0)
+#define k5_mutex_destroy(M)	pthread_mutex_destroy(M)
+#define k5_mutex_lock(M)	pthread_mutex_lock(M)
+#define k5_mutex_unlock(M)	pthread_mutex_unlock(M)
+
+#else /* DEBUG_THREADS */
+
+typedef struct {
+    k5_mutex_debug_info debug;
+    pthread_mutex_t lock;
+} k5_mutex_t;
+#define K5_MUTEX_INITIALIZER	{ K5_MUTEX_DEBUG_INITIALIZER, PTHREAD_MUTEX_INITIALIZER }
+#define k5_mutex_init(M)	(k5_mutex_debug_init(&(M)->debug),	      \
+				 assert(0==pthread_mutex_init(&(M)->lock,0)), \
+				 0)
+#define k5_mutex_destroy(M)	(k5_mutex_debug_init(&(M)->debug),	      \
+				 assert(0==pthread_mutex_destroy(&(M)->lock))
+#define k5_mutex_lock(M)	(k5_mutex_debug_lock(&(M)->debug),	    \
+				 assert(0==pthread_mutex_lock(&(M)->lock)), \
+				 0)
+#define k5_mutex_unlock(M)	(k5_mutex_debug_unlock(&(M)->debug),	      \
+				 assert(0==pthread_mutex_unlock(&(M)->lock)), \
+				 0)
+
+#endif /* DEBUG_THREADS ? */
+
+#if 0
+/* *** This will need to change.
+   We'd prefer to use only one POSIX data key.
+
+   And we need to do some additional bookkeeping for dealing with
+   unloading libraries (free storage, destroy the key), such that we
+   can't just map the functions to POSIX in the long term.  */
+typedef pthread_key_t k5_key_t;
+#define k5_key_create(K,D)	pthread_key_create(K,D)
+#define k5_getspecific(K)	pthread_getspecific(K)
+#define k5_setspecific(K,P)	pthread_setspecific(K,P)
+#endif
+
+#else /* ! ENABLE_THREADS */
+
+#ifdef DEBUG_THREADS
+
+#include <assert.h>
+
+/* Even if not using threads, use some mutex-like locks to see if
+   we're pairing up lock and unlock calls properly.  */
+
+#define k5_mutex_t		k5_mutex_debug_info
+#define K5_MUTEX_INITIALIZER	K5_MUTEX_DEBUG_INITIALIZER
+#define k5_mutex_init		k5_mutex_debug_init
+#define k5_mutex_destroy	k5_mutex_debug_destroy
+#define k5_mutex_lock		k5_mutex_debug_lock
+#define k5_mutex_unlock		k5_mutex_debug_unlock
+
+#else /* ! DEBUG_THREADS */
+
+/* no-op versions */
+
+typedef char k5_mutex_t;
+#define K5_MUTEX_INITIALIZER	0
+#define k5_mutex_init(M)	(*(M) = 0, *(M) = *(M))
+#define k5_mutex_destroy(M)	(0)
+#define k5_mutex_lock(M)	(0)
+#define k5_mutex_unlock(M)	(0)
+
+#endif /* DEBUG_THREADS ? */
+
+#endif /* ENABLE_THREADS ? */
+
+#endif /* K5_MUTEX_INITIALIZER for multiple inclusion */