implement hazard pointer data structure

this is a mechanism to allow safe lock-free data structures.

lib/isc/Makefile.in

@@ -50,8 +50,8 @@ OBJS =		pk11.@O@ pk11_result.@O@ \
 		backtrace.@O@ base32.@O@ base64.@O@ \
 		bind9.@O@ buffer.@O@ bufferlist.@O@ \
 		commandline.@O@ counter.@O@ crc64.@O@ error.@O@ entropy.@O@ \
-		event.@O@ hash.@O@ ht.@O@ heap.@O@ hex.@O@ hmac.@O@ \
-		httpd.@O@ iterated_hash.@O@ \
+		event.@O@ hash.@O@ ht.@O@ heap.@O@ hex.@O@ \
+		hmac.@O@ hp.@O@ httpd.@O@ iterated_hash.@O@ \
 		lex.@O@ lfsr.@O@ lib.@O@ log.@O@ \
 		md.@O@ mem.@O@ mutexblock.@O@ \
 		netaddr.@O@ netscope.@O@ nonce.@O@ openssl_shim.@O@ pool.@O@ \
@@ -69,8 +69,8 @@ SRCS =		pk11.c pk11_result.c \
 		aes.c app.c assertions.c \
 		backtrace.c base32.c base64.c bind9.c \
 		buffer.c bufferlist.c commandline.c counter.c crc64.c \
-		entropy.c error.c event.c hash.c ht.c heap.c hex.c hmac.c \
-		httpd.c iterated_hash.c \
+		entropy.c error.c event.c hash.c ht.c heap.c \
+		hex.c hmac.c hp.c httpd.c iterated_hash.c \
 		lex.c lfsr.c lib.c log.c \
 		md.c mem.c mutexblock.c \
 		netaddr.c netscope.c nonce.c openssl_shim.c pool.c \

lib/isc/hp.c

@@ -0,0 +1,222 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*
+ * Hazard Pointer implementation.
+ *
+ * This work is based on C++ code available from:
+ * https://github.com/pramalhe/ConcurrencyFreaks/
+ *
+ * Copyright (c) 2014-2016, Pedro Ramalhete, Andreia Correia
+ * All rights reserved.
+ *
+ * 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 Concurrency Freaks 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 <COPYRIGHT HOLDER>
+ * 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.
+ */
+
+#include <inttypes.h>
+
+#include <isc/atomic.h>
+#include <isc/hp.h>
+#include <isc/string.h>
+#include <isc/mem.h>
+#include <isc/util.h>
+
+#define HP_MAX_THREADS 128
+#define HP_MAX_HPS 4			/* This is named 'K' in the HP paper */
+#define CLPAD (128 / sizeof(uintptr_t))
+#define HP_THRESHOLD_R 0		/* This is named 'R' in the HP paper */
+
+/* Maximum number of retired objects per thread */
+#define MAX_RETIRED (HP_MAX_THREADS * HP_MAX_HPS)
+
+#define TID_UNKNOWN -1
+
+static atomic_int_fast32_t tid_v_base;
+static bool tid_v_initialized;
+
+#if defined(HAVE_TLS)
+#if defined(HAVE_THREAD_LOCAL)
+#include <threads.h>
+static thread_local int tid_v = TID_UNKNOWN;
+#elif defined(HAVE___THREAD)
+static __thread int tid_v = TID_UNKNOWN;
+#elif defined(HAVE___DECLSPEC_THREAD)
+static __declspec( thread ) int tid_v = TID_UNKNOWN;
+#else  /* if defined(HAVE_THREAD_LOCAL) */
+#error "Unknown method for defining a TLS variable!"
+#endif /* if defined(HAVE_THREAD_LOCAL) */
+#else  /* if defined(HAVE_TLS) */
+#error "Thread-local storage support is required!"
+#endif /* if defined(HAVE_TLS) */
+
+typedef struct retirelist {
+	int			size;
+	uintptr_t		list[MAX_RETIRED];
+} retirelist_t;
+
+struct isc_hp {
+	int			max_hps;
+	isc_mem_t		*mctx;
+	atomic_uintptr_t	*hp[HP_MAX_THREADS];
+	retirelist_t		*rl[HP_MAX_THREADS];
+	isc_hp_deletefunc_t	*deletefunc;
+};
+
+static inline int
+tid() {
+	if (!tid_v_initialized) {
+		atomic_init(&tid_v_base, 0);
+		tid_v_initialized = true;
+	}
+	if (tid_v == TID_UNKNOWN) {
+		tid_v = atomic_fetch_add(&tid_v_base, 1);
+		REQUIRE(tid_v < HP_MAX_THREADS);
+	}
+
+	return (tid_v);
+}
+
+isc_hp_t *
+isc_hp_new(isc_mem_t *mctx, size_t max_hps, isc_hp_deletefunc_t *deletefunc) {
+	isc_hp_t *hp = isc_mem_get(mctx, sizeof(*hp));
+
+	if (max_hps == 0) {
+		max_hps = HP_MAX_HPS;
+	}
+
+	*hp = (isc_hp_t){
+		.max_hps = max_hps,
+		.deletefunc = deletefunc
+	};
+
+	isc_mem_attach(mctx, &hp->mctx);
+
+	for (int i = 0; i < HP_MAX_THREADS; i++) {
+		hp->hp[i] = isc_mem_get(mctx, CLPAD * 2 * sizeof(hp->hp[i][0]));
+		hp->rl[i] = isc_mem_get(mctx, sizeof(*hp->rl[0]));
+		*hp->rl[i] = (retirelist_t) { .size = 0 };
+
+		for (int j = 0; j < hp->max_hps; j++) {
+			atomic_init(&hp->hp[i][j], 0);
+		}
+	}
+
+	return (hp);
+}
+
+void
+isc_hp_destroy(isc_hp_t *hp) {
+	for (int i = 0; i < HP_MAX_THREADS; i++) {
+		isc_mem_put(hp->mctx, hp->hp[i],
+			    CLPAD * 2 * sizeof(uintptr_t));
+
+		for (int j = 0; j < hp->rl[i]->size; j++) {
+			void *data = (void *)hp->rl[i]->list[j];
+			hp->deletefunc(data);
+		}
+
+		isc_mem_put(hp->mctx, hp->rl[i], sizeof(*hp->rl[0]));
+	}
+
+	isc_mem_putanddetach(&hp->mctx, hp, sizeof(*hp));
+}
+
+void
+isc_hp_clear(isc_hp_t *hp) {
+	for (int i = 0; i < hp->max_hps; i++) {
+		atomic_store_release(&hp->hp[tid()][i], 0);
+	}
+}
+
+void isc_hp_clear_one(isc_hp_t *hp, int ihp) {
+	atomic_store_release(&hp->hp[tid()][ihp], 0);
+}
+
+uintptr_t
+isc_hp_protect(isc_hp_t *hp, int ihp, atomic_uintptr_t *atom) {
+	uintptr_t n = 0;
+	uintptr_t ret;
+	while ((ret = atomic_load(atom)) != n) {
+		atomic_store(&hp->hp[tid()][ihp], ret);
+		n = ret;
+	}
+	return (ret);
+}
+
+uintptr_t
+isc_hp_protect_ptr(isc_hp_t *hp, int ihp, atomic_uintptr_t ptr) {
+	atomic_store(&hp->hp[tid()][ihp], atomic_load(&ptr));
+	return (atomic_load(&ptr));
+}
+
+uintptr_t
+isc_hp_protect_release(isc_hp_t *hp, int ihp, atomic_uintptr_t ptr) {
+	atomic_store_release(&hp->hp[tid()][ihp], atomic_load(&ptr));
+	return (atomic_load(&ptr));
+}
+
+void
+isc_hp_retire(isc_hp_t *hp, uintptr_t ptr) {
+	hp->rl[tid()]->list[hp->rl[tid()]->size++] = ptr;
+	INSIST(hp->rl[tid()]->size < MAX_RETIRED);
+
+	if (hp->rl[tid()]->size < HP_THRESHOLD_R) {
+		return;
+	}
+
+	for (int iret = 0; iret < hp->rl[tid()]->size; iret++) {
+		uintptr_t obj = hp->rl[tid()]->list[iret];
+		bool can_delete = true;
+		for (int itid = 0;
+		     itid < HP_MAX_THREADS && can_delete;
+		     itid++)
+		{
+			for (int ihp = hp->max_hps-1; ihp >= 0; ihp--) {
+				if (atomic_load(&hp->hp[itid][ihp]) == obj) {
+					can_delete = false;
+					break;
+				}
+			}
+		}
+
+		if (can_delete) {
+			size_t bytes = (hp->rl[tid()]->size - iret) *
+				sizeof(hp->rl[tid()]->list[0]);
+			memmove(&hp->rl[tid()]->list[iret],
+				&hp->rl[tid()]->list[iret + 1],
+				bytes);
+			hp->rl[tid()]->size--;
+			hp->deletefunc((void *)obj);
+		}
+	}
+}

lib/isc/include/isc/Makefile.in

@@ -23,7 +23,7 @@ HEADERS =	aes.h app.h assertions.h atomic.h backtrace.h \
 		commandline.h counter.h crc64.h deprecated.h \
 		endian.h errno.h error.h event.h eventclass.h \
 		file.h formatcheck.h fsaccess.h fuzz.h \
-		hash.h heap.h hex.h hmac.h ht.h httpd.h \
+		hash.h heap.h hex.h hmac.h hp.h ht.h httpd.h \
 		interfaceiter.h iterated_hash.h \
 		lang.h lex.h lfsr.h lib.h likely.h list.h log.h \
 		magic.h md.h mem.h meminfo.h mutexblock.h \

lib/isc/include/isc/hp.h

@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*
+ * Hazard Pointer implementation.
+ *
+ * This work is based on C++ code available from:
+ * https://github.com/pramalhe/ConcurrencyFreaks/
+ *
+ * Copyright (c) 2014-2016, Pedro Ramalhete, Andreia Correia
+ * All rights reserved.
+ *
+ * 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 Concurrency Freaks 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 <COPYRIGHT HOLDER>
+ * 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.
+ */
+
+#include <isc/atomic.h>
+#include <isc/string.h>
+#include <isc/mem.h>
+#include <isc/types.h>
+#include <isc/util.h>
+
+/*%
+ * Hazard pointers are a mechanism for protecting objects in memory
+ * from being deleted by other threads while in use. This allows
+ * safe lock-free data structures.
+ *
+ * This is an adaptation of the ConcurrencyFreaks implementation in C.
+ * More details available at https://github.com/pramalhe/ConcurrencyFreaks,
+ * in the file HazardPointers.hpp.
+ */
+
+typedef void
+(isc_hp_deletefunc_t)(void *);
+
+isc_hp_t *
+isc_hp_new(isc_mem_t *mctx, size_t max_hps, isc_hp_deletefunc_t *deletefunc);
+/*%<
+ * Create a new hazard pointer array of size 'max_hps' (or a reasonable
+ * default value if 'max_hps' is 0). The function 'deletefunc' will be
+ * used to delete objects protected by hazard pointers when it becomes
+ * safe to retire them.
+ */
+
+void
+isc_hp_destroy(isc_hp_t *hp);
+/*%<
+ * Destroy a hazard pointer array and clean up all objects protected
+ * by hazard pointers.
+ */
+
+void
+isc_hp_clear(isc_hp_t *hp);
+/*%<
+ * Clear all hazard pointers in the array for the current thread.
+ *
+ * Progress condition: wait-free bounded (by max_hps)
+ */
+
+void
+isc_hp_clear_one(isc_hp_t *hp, int ihp);
+/*%<
+ * Clear a specified hazard pointer in the array for the current thread.
+ *
+ * Progress condition: wait-free population oblivious.
+ */
+
+uintptr_t
+isc_hp_protect(isc_hp_t *hp, int ihp, atomic_uintptr_t *atom);
+/*%<
+ * Protect an object referenced by 'atom' with a hazard pointer for the
+ * current thread.
+ *
+ * Progress condition: lock-free.
+ */
+
+uintptr_t
+isc_hp_protect_ptr(isc_hp_t *hp, int ihp, atomic_uintptr_t ptr);
+/*%<
+ * This returns the same value that is passed as ptr, which is sometimes
+ * useful.
+ *
+ * Progress condition: wait-free population oblivious.
+ */
+
+uintptr_t
+isc_hp_protect_release(isc_hp_t *hp, int ihp, atomic_uintptr_t ptr);
+/*%<
+ * Same as isc_hp_protect_ptr(), but explicitly uses memory_order_release.
+ *
+ * Progress condition: wait-free population oblivious.
+ */
+
+void
+isc_hp_retire(isc_hp_t *hp, uintptr_t ptr);
+/*%<
+ * Retire an object that is no longer in use by any thread, calling
+ * the delete function that was specified in isc_hp_new().
+ *
+ * Progress condition: wait-free bounded (by the number of threads squared)
+ */

lib/isc/include/isc/types.h

@@ -43,6 +43,8 @@ typedef ISC_LIST(isc_event_t)		isc_eventlist_t;	/*%< Event List */
 typedef unsigned int			isc_eventtype_t;	/*%< Event Type */
 typedef uint32_t			isc_fsaccess_t;		/*%< FS Access */
 typedef struct isc_hash			isc_hash_t;		/*%< Hash */
+typedef struct isc_hp			isc_hp_t;		/*%< Hazard
+								  pointer */
 typedef struct isc_httpd		isc_httpd_t;		/*%< HTTP client */
 typedef void (isc_httpdfree_t)(isc_buffer_t *, void *);		/*%< HTTP free function */
 typedef struct isc_httpdmgr		isc_httpdmgr_t;		/*%< HTTP manager */

lib/isc/win32/libisc.def.in

@@ -242,6 +242,13 @@ isc_heap_insert
 isc_hex_decodestring
 isc_hex_tobuffer
 isc_hex_totext
+isc_hp_clear
+isc_hp_destroy
+isc_hp_protect
+isc_hp_protect_ptr
+isc_hp_protect_release
+isc_hp_new
+isc_hp_retire
 isc_hmac
 isc_hmac_new
 isc_hmac_free
@@ -252,6 +259,13 @@ isc_hmac_final
 isc_hmac_get_md_type
 isc_hmac_get_size
 isc_hmac_get_block_size
+isc_hp_new
+isc_hp_destroy
+isc_hp_clear
+isc_hp_protect
+isc_hp_protect_ptr
+isc_hp_protect_release
+isc_hp_retire
 isc_ht_add
 isc_ht_count
 isc_ht_delete

lib/isc/win32/libisc.vcxproj.filters.in

@@ -104,6 +104,9 @@
     <ClInclude Include="..\include\isc\hmac.h">
       <Filter>Library Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="..\include\isc\hp.h">
+      <Filter>Library Header Files</Filter>
+    </ClInclude>
     <ClInclude Include="..\include\isc\ht.h">
       <Filter>Library Header Files</Filter>
     </ClInclude>
@@ -500,6 +503,9 @@
     <ClCompile Include="..\hmac.c">
       <Filter>Library Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\hp.c">
+      <Filter>Library Source Files</Filter>
+    </ClCompile>
     <ClCompile Include="..\ht.c">
       <Filter>Library Source Files</Filter>
     </ClCompile>

lib/isc/win32/libisc.vcxproj.in

@@ -311,6 +311,7 @@ copy InstallFiles ..\Build\Release\
     <ClInclude Include="..\include\isc\heap.h" />
     <ClInclude Include="..\include\isc\hex.h" />
     <ClInclude Include="..\include\isc\hmac.h" />
+    <ClInclude Include="..\include\isc\hp.h" />
     <ClInclude Include="..\include\isc\ht.h" />
     <ClInclude Include="..\include\isc\httpd.h" />
     <ClInclude Include="..\include\isc\interfaceiter.h" />
@@ -421,6 +422,7 @@ copy InstallFiles ..\Build\Release\
     <ClCompile Include="..\heap.c" />
     <ClCompile Include="..\hex.c" />
     <ClCompile Include="..\hmac.c" />
+    <ClCompile Include="..\hp.c" />
     <ClCompile Include="..\ht.c" />
     <ClCompile Include="..\httpd.c" />
     <ClCompile Include="..\iterated_hash.c" />

util/copyrights

@@ -2148,6 +2148,7 @@
 ./lib/isc/heap.c				C	1997,1998,1999,2000,2001,2004,2005,2006,2007,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019
 ./lib/isc/hex.c					C	2000,2001,2002,2003,2004,2005,2007,2008,2013,2014,2015,2016,2018,2019
 ./lib/isc/hmac.c				C	2000,2001,2004,2005,2006,2007,2009,2011,2012,2013,2014,2015,2016,2017,2018,2019
+./lib/isc/hp.c					C	2019
 ./lib/isc/ht.c					C	2016,2017,2018,2019
 ./lib/isc/httpd.c				C	2006,2007,2008,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019
 ./lib/isc/include/Makefile.in			MAKE	1998,1999,2000,2001,2004,2007,2012,2014,2016,2018,2019
@@ -2179,6 +2180,7 @@
 ./lib/isc/include/isc/heap.h			C	1997,1998,1999,2000,2001,2004,2005,2006,2007,2009,2012,2016,2018,2019
 ./lib/isc/include/isc/hex.h			C	2000,2001,2004,2005,2006,2007,2008,2016,2018,2019
 ./lib/isc/include/isc/hmac.h			C	2000,2001,2004,2005,2006,2007,2009,2011,2012,2013,2014,2015,2016,2017,2018,2019
+./lib/isc/include/isc/hp.h			C	2019
 ./lib/isc/include/isc/ht.h			C	2016,2017,2018,2019
 ./lib/isc/include/isc/httpd.h			C	2006,2007,2008,2014,2016,2018,2019
 ./lib/isc/include/isc/interfaceiter.h		C	1999,2000,2001,2004,2005,2006,2007,2016,2018,2019