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+/**
+ * testcode/checklocks.h - wrapper on locks that checks access.
+ *
+ * Copyright (c) 2007, NLnet Labs. All rights reserved.
+ * 
+ * This software is open source.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 
+ * Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 
+ * Neither the name of the NLNET LABS nor the names of its contributors may
+ * be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef TESTCODE_CHECK_LOCKS_H
+#define TESTCODE_CHECK_LOCKS_H
+
+/**
+ * \file
+ * Locks that are checked.
+ *
+ * Holds information per lock and per thread.
+ * That information is protected by a mutex (unchecked).
+ *
+ * Checks:
+ *      o which func, file, line created the lock.
+ *      o contention count, measures amount of contention on the lock.
+ *      o the memory region(s) that the lock protects are
+ *        memcmp'ed to ascertain no race conditions.
+ *      o checks that locks are unlocked properly (before deletion).
+ *        keeps which func, file, line that locked it.
+ *	o checks deadlocks with timeout so it can print errors for them.
+ *
+ * Limitations:
+ *	o Detects unprotected memory access when the lock is locked or freed,
+ *	  which detects races only if they happen, and only if in protected
+ *	  memory areas.
+ *	o Detects deadlocks by timeout, so approximately, as they happen.
+ *	o Does not check order of locking.
+ *	o Uses a lot of memory.
+ *	o The checks use locks themselves, changing scheduling,
+ *	  thus changing what races you see.
+ */
+
+#ifdef USE_THREAD_DEBUG
+#ifndef HAVE_PTHREAD
+/* we need the *timed*lock() routines to use for deadlock detection. */
+#error "Need pthreads for checked locks"
+#endif
+/******************* THREAD DEBUG ************************/
+#include <pthread.h>
+
+/** How many threads to allocate for */
+#define THRDEBUG_MAX_THREADS 32 /* threads */
+/** do we check locking order */
+extern int check_locking_order;
+
+/**
+ * Protection memory area.
+ * It is copied to a holding buffer to compare against later.
+ * Note that it may encompass the lock structure.
+ */
+struct protected_area {
+	/** where the memory region starts */
+	void* region;
+	/** size of the region */
+	size_t size;
+	/** backbuffer that holds a copy, of same size. */
+	void* hold;
+	/** next protected area in list */
+	struct protected_area* next;
+};
+
+/**
+ * Per thread information for locking debug wrappers. 
+ */
+struct thr_check {
+	/** thread id */
+	pthread_t id;
+	/** real thread func */
+	void* (*func)(void*);
+	/** func user arg */
+	void* arg;
+	/** number of thread in list structure */
+	int num;
+	/** instance number - how many locks have been created by thread */
+	int locks_created;
+	/** file to write locking order information to */
+	FILE* order_info;
+	/** 
+	 * List of locks that this thread is holding, double
+	 * linked list. The first element is the most recent lock acquired.
+	 * So it represents the stack of locks acquired. (of all types).
+	 */
+	struct checked_lock *holding_first, *holding_last;
+	/** if the thread is currently waiting for a lock, which one */
+	struct checked_lock* waiting;
+};
+
+/**
+ * One structure for all types of locks.
+ */
+struct checked_lock {
+	/** mutex for exclusive access to this structure */
+	pthread_mutex_t lock;
+	/** list of memory regions protected by this checked lock */
+	struct protected_area* prot;
+	/** where was this lock created */
+	const char* create_func, *create_file;
+	/** where was this lock created */
+	int create_line;
+	/** unique instance identifier */
+	int create_thread, create_instance;
+	/** contention count */
+	size_t contention_count;
+	/** number of times locked, ever */
+	size_t history_count;
+	/** hold count (how many threads are holding this lock) */
+	int hold_count;
+	/** how many threads are waiting for this lock */
+	int wait_count;
+	/** who touched it last */
+	const char* holder_func, *holder_file;
+	/** who touched it last */
+	int holder_line;
+	/** who owns the lock now */
+	struct thr_check* holder;
+	/** for rwlocks, the writelock holder */
+	struct thr_check* writeholder;
+
+	/** next lock a thread is holding (less recent) */
+	struct checked_lock* next_held_lock[THRDEBUG_MAX_THREADS];
+	/** prev lock a thread is holding (more recent) */
+	struct checked_lock* prev_held_lock[THRDEBUG_MAX_THREADS];
+
+	/** type of lock */
+	enum check_lock_type {
+		/** basic mutex */
+		check_lock_mutex,
+		/** fast spinlock */
+		check_lock_spinlock,
+		/** rwlock */
+		check_lock_rwlock
+	} type;
+	/** the lock itself, see type to disambiguate the union */
+	union {
+		/** mutex */
+		pthread_mutex_t mutex;
+		/** spinlock */
+		pthread_spinlock_t spinlock;
+		/** rwlock */
+		pthread_rwlock_t rwlock;
+	} u;
+};
+
+/**
+ * Additional call for the user to specify what areas are protected
+ * @param lock: the lock that protects the area. It can be inside the area.
+ *	The lock must be inited. Call with user lock. (any type).
+ *	It demangles the lock itself (struct checked_lock**).
+ * @param area: ptr to mem.
+ * @param size: length of area.
+ * You can call it multiple times with the same lock to give several areas.
+ * Call it when you are done initialising the area, since it will be copied
+ * at this time and protected right away against unauthorised changes until 
+ * the next lock() call is done.
+ */
+void lock_protect(void* lock, void* area, size_t size);
+
+/**
+ * Remove protected area from lock.
+ * No need to call this when deleting the lock.
+ * @param lock: the lock, any type, (struct checked_lock**).
+ * @param area: pointer to memory.
+ */
+void lock_unprotect(void* lock, void* area);
+
+/**
+ * Get memory associated with a checked lock
+ * @param lock: the checked lock, any type. (struct checked_lock**).
+ * @return: in bytes, including protected areas.
+ */
+size_t lock_get_mem(void* lock);
+
+/**
+ * Initialise checklock. Sets up internal debug structures.
+ */
+void checklock_start(void);
+
+/**
+ * Cleanup internal debug state.
+ */
+void checklock_stop(void);
+
+/**
+ * Init locks.
+ * @param type: what type of lock this is.
+ * @param lock: ptr to user alloced ptr structure. This is inited.
+ *     So an alloc is done and the ptr is stored as result.
+ * @param func: caller function name.
+ * @param file: caller file name.
+ * @param line: caller line number.
+ */
+void checklock_init(enum check_lock_type type, struct checked_lock** lock,
+	const char* func, const char* file, int line);
+
+/**
+ * Destroy locks. Free the structure.
+ * @param type: what type of lock this is.
+ * @param lock: ptr to user alloced structure. This is destroyed.
+ * @param func: caller function name.
+ * @param file: caller file name.
+ * @param line: caller line number.
+ */
+void checklock_destroy(enum check_lock_type type, struct checked_lock** lock,
+	const char* func, const char* file, int line);
+
+/**
+ * Acquire readlock.
+ * @param type: what type of lock this is. Had better be a rwlock.
+ * @param lock: ptr to lock.
+ * @param func: caller function name.
+ * @param file: caller file name.
+ * @param line: caller line number.
+ */
+void checklock_rdlock(enum check_lock_type type, struct checked_lock* lock,
+	const char* func, const char* file, int line);
+
+/**
+ * Acquire writelock.
+ * @param type: what type of lock this is. Had better be a rwlock.
+ * @param lock: ptr to lock.
+ * @param func: caller function name.
+ * @param file: caller file name.
+ * @param line: caller line number.
+ */
+void checklock_wrlock(enum check_lock_type type, struct checked_lock* lock,
+	const char* func, const char* file, int line);
+
+/**
+ * Locks.
+ * @param type: what type of lock this is. Had better be mutex or spinlock.
+ * @param lock: the lock.
+ * @param func: caller function name.
+ * @param file: caller file name.
+ * @param line: caller line number.
+ */
+void checklock_lock(enum check_lock_type type, struct checked_lock* lock,
+	const char* func, const char* file, int line);
+
+/**
+ * Unlocks.
+ * @param type: what type of lock this is.
+ * @param lock: the lock.
+ * @param func: caller function name.
+ * @param file: caller file name.
+ * @param line: caller line number.
+ */
+void checklock_unlock(enum check_lock_type type, struct checked_lock* lock,
+	const char* func, const char* file, int line);
+
+/**
+ * Create thread.
+ * @param thr: Thread id, where to store result.
+ * @param func: thread start function.
+ * @param arg: user argument.
+ */
+void checklock_thrcreate(pthread_t* thr, void* (*func)(void*), void* arg);
+
+/**
+ * Wait for thread to exit. Returns thread return value.
+ * @param thread: thread to wait for.
+ */
+void checklock_thrjoin(pthread_t thread);
+
+/** structures to enable compiler type checking on the locks. 
+ * Also the pointer makes it so that the lock can be part of the protected
+ * region without any possible problem (since the ptr will stay the same.)
+ * i.e. there can be contention and readlocks stored in checked_lock, while
+ * the protected area stays the same, even though it contains (ptr to) lock.
+ */
+struct checked_lock_rw { struct checked_lock* c_rw; };
+/** structures to enable compiler type checking on the locks. */
+struct checked_lock_mutex { struct checked_lock* c_m; };
+/** structures to enable compiler type checking on the locks. */
+struct checked_lock_spl { struct checked_lock* c_spl; };
+
+/** debugging rwlock */
+typedef struct checked_lock_rw lock_rw_t;
+#define lock_rw_init(lock) checklock_init(check_lock_rwlock, &((lock)->c_rw), __func__, __FILE__, __LINE__)
+#define lock_rw_destroy(lock) checklock_destroy(check_lock_rwlock, &((lock)->c_rw), __func__, __FILE__, __LINE__)
+#define lock_rw_rdlock(lock) checklock_rdlock(check_lock_rwlock, (lock)->c_rw, __func__, __FILE__, __LINE__)
+#define lock_rw_wrlock(lock) checklock_wrlock(check_lock_rwlock, (lock)->c_rw, __func__, __FILE__, __LINE__)
+#define lock_rw_unlock(lock) checklock_unlock(check_lock_rwlock, (lock)->c_rw, __func__, __FILE__, __LINE__)
+
+/** debugging mutex */
+typedef struct checked_lock_mutex lock_basic_t;
+#define lock_basic_init(lock) checklock_init(check_lock_mutex, &((lock)->c_m), __func__, __FILE__, __LINE__)
+#define lock_basic_destroy(lock) checklock_destroy(check_lock_mutex, &((lock)->c_m), __func__, __FILE__, __LINE__)
+#define lock_basic_lock(lock) checklock_lock(check_lock_mutex, (lock)->c_m, __func__, __FILE__, __LINE__)
+#define lock_basic_unlock(lock) checklock_unlock(check_lock_mutex, (lock)->c_m, __func__, __FILE__, __LINE__)
+
+/** debugging spinlock */
+typedef struct checked_lock_spl lock_quick_t;
+#define lock_quick_init(lock) checklock_init(check_lock_spinlock, &((lock)->c_spl), __func__, __FILE__, __LINE__)
+#define lock_quick_destroy(lock) checklock_destroy(check_lock_spinlock, &((lock)->c_spl), __func__, __FILE__, __LINE__)
+#define lock_quick_lock(lock) checklock_lock(check_lock_spinlock, (lock)->c_spl, __func__, __FILE__, __LINE__)
+#define lock_quick_unlock(lock) checklock_unlock(check_lock_spinlock, (lock)->c_spl, __func__, __FILE__, __LINE__)
+
+/** we use the pthread id, our thr_check structure is kept behind the scenes */
+typedef pthread_t ub_thread_t;
+#define ub_thread_create(thr, func, arg) checklock_thrcreate(thr, func, arg)
+#define ub_thread_self() pthread_self()
+#define ub_thread_join(thread) checklock_thrjoin(thread)
+
+typedef pthread_key_t ub_thread_key_t;
+#define ub_thread_key_create(key, f) LOCKRET(pthread_key_create(key, f))
+#define ub_thread_key_set(key, v) LOCKRET(pthread_setspecific(key, v))
+#define ub_thread_key_get(key) pthread_getspecific(key)
+
+#endif /* USE_THREAD_DEBUG */
+#endif /* TESTCODE_CHECK_LOCKS_H */