From 343f819f5a4e7cd1396cd9f31070fa6520d308e7 Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Thu, 4 Apr 2019 11:04:54 +0200 Subject: WIP: osmo_it_msgq: Osmocom Inter-thread Message Queue This implements an inter-thread message queue based on top of osmocom msgb, linked lists, eventfd and pthread mutex. Change-Id: I30a7233cb0b51a883ad85c8c4165270b32c4be61 --- configure.ac | 2 +- include/Makefile.am | 1 + include/osmocom/core/it_msgq.h | 44 ++++++++ src/Makefile.am | 3 +- src/it_msgq.c | 228 +++++++++++++++++++++++++++++++++++++++++ tests/Makefile.am | 7 +- tests/it_msgq/it_msgq_test.c | 106 +++++++++++++++++++ tests/it_msgq/it_msgq_test.ok | 15 +++ tests/testsuite.at | 6 ++ 9 files changed, 409 insertions(+), 3 deletions(-) create mode 100644 include/osmocom/core/it_msgq.h create mode 100644 src/it_msgq.c create mode 100644 tests/it_msgq/it_msgq_test.c create mode 100644 tests/it_msgq/it_msgq_test.ok diff --git a/configure.ac b/configure.ac index d717a0bb..4f26f925 100644 --- a/configure.ac +++ b/configure.ac @@ -57,7 +57,7 @@ AC_SUBST(LTLDFLAGS_OSMOCTRL) dnl checks for header files AC_HEADER_STDC -AC_CHECK_HEADERS(execinfo.h sys/select.h sys/socket.h sys/timerfd.h syslog.h ctype.h netinet/tcp.h netinet/in.h) +AC_CHECK_HEADERS(execinfo.h sys/select.h sys/socket.h sys/eventfd.h sys/timerfd.h syslog.h ctype.h netinet/tcp.h netinet/in.h) # for src/conv.c AC_FUNC_ALLOCA AC_SEARCH_LIBS([dlopen], [dl dld], [LIBRARY_DLOPEN="$LIBS";LIBS=""]) diff --git a/include/Makefile.am b/include/Makefile.am index a82d6ac4..8bd106e3 100644 --- a/include/Makefile.am +++ b/include/Makefile.am @@ -27,6 +27,7 @@ nobase_include_HEADERS = \ osmocom/core/gsmtap.h \ osmocom/core/gsmtap_util.h \ osmocom/core/isdnhdlc.h \ + osmocom/core/it_msgq.h \ osmocom/core/linuxlist.h \ osmocom/core/linuxrbtree.h \ osmocom/core/logging.h \ diff --git a/include/osmocom/core/it_msgq.h b/include/osmocom/core/it_msgq.h new file mode 100644 index 00000000..17d80d36 --- /dev/null +++ b/include/osmocom/core/it_msgq.h @@ -0,0 +1,44 @@ +#pragma once + +#include +#include +#include +#include + +/*! \defgroup it_msgq Inter-ThreadMessage Queue + * @{ + * \file it_msgq.h */ + +struct osmo_it_msgq { + /* entry in global list of message queues */ + struct llist_head entry; + + /* the actual list of msgb's. HEAD: first in queue; TAIL: last in queue */ + struct llist_head list; + /* A pthread mutex to safeguard accesses to the queue. No rwlock as we always write. */ + pthread_mutex_t mutex; + /* Current count of messages in the queue */ + unsigned int current_length; + /* osmo-fd wrapped eventfd */ + struct osmo_fd event_ofd; + + /* a user-defined name for this queue */ + const char *name; + /* maximum permitted length of queue */ + unsigned int max_length; + /* read call-back, called for each de-queued message */ + void (*read_cb)(struct osmo_it_msgq *q, struct msgb *msg); + /* opaque data pointer passed through to call-back function */ + void *data; +}; + +struct osmo_it_msgq *osmo_it_msgq_by_name(const char *name); +int osmo_it_msgq_enqueue(struct osmo_it_msgq *queue, struct msgb *msg); +struct msgb *osmo_it_msgq_dequeue(struct osmo_it_msgq *queue); +struct osmo_it_msgq *osmo_it_msgq_alloc(void *ctx, const char *name, unsigned int max_length, + void (*read_cb)(struct osmo_it_msgq *q, struct msgb *msg), + void *data); +void osmo_it_msgq_destroy(struct osmo_it_msgq *q); +void osmo_it_msgq_flush(struct osmo_it_msgq *q); + +/*! @} */ diff --git a/src/Makefile.am b/src/Makefile.am index 714b5eac..b47d8360 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -12,7 +12,7 @@ endif lib_LTLIBRARIES = libosmocore.la -libosmocore_la_LIBADD = $(BACKTRACE_LIB) $(TALLOC_LIBS) $(LIBRARY_RT) +libosmocore_la_LIBADD = $(BACKTRACE_LIB) $(TALLOC_LIBS) $(LIBRARY_RT) -lpthread libosmocore_la_SOURCES = context.c timer.c timer_gettimeofday.c timer_clockgettime.c \ select.c signal.c msgb.c bits.c \ bitvec.c bitcomp.c counter.c fsm.c \ @@ -27,6 +27,7 @@ libosmocore_la_SOURCES = context.c timer.c timer_gettimeofday.c timer_clockgetti tdef.c \ sockaddr_str.c \ use_count.c \ + it_msgq.c \ $(NULL) if HAVE_SSSE3 diff --git a/src/it_msgq.c b/src/it_msgq.c new file mode 100644 index 00000000..dd28034f --- /dev/null +++ b/src/it_msgq.c @@ -0,0 +1,228 @@ +/*! \file it_msgq.c + * Osmocom Inter-Thread message queue implementation */ +/* (C) 2019 by Harald Welte + * All Rights Reserved. + * + * SPDX-License-Identifier: GPL-2.0+ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, + * MA 02110-1301, USA. + */ + +/*! \addtogroup it_msgq + * @{ + * Inter-Thread Message Queue. + * + * This implements a general-purpose message queue between threads. It + * uses 'struct msgb' as elements in the queue and an eventfd-based notification + * mechanism. Hence, it can be used for pretty much anything that can be stored + * inside msgbs, including msgb-wrapped osmo_prim. + * + * The idea is that the sending thread simply calls osmo_it_msgq_enqueue(). + * The receiving thread is woken up from its osmo_select_main() loop by eventfd, + * and a general osmo_fd callback function for the eventfd will dequeue each msgb + * and call a queue-specific callback function. + */ + +#include "../config.h" + +#ifdef HAVE_SYS_EVENTFD_H + +#include +#include +#include +#include +#include + +#include +#include +#include + +static int eventfd_increment(int fd, uint64_t inc) +{ + int rc; + + rc = write(fd, &inc, sizeof(inc)); + if (rc != sizeof(inc)) + return -1; + + return 0; +} + +/* global (for all threads) list of message queues in a program + associated lock */ +static LLIST_HEAD(msg_queues); +static pthread_rwlock_t msg_queues_rwlock; + +static struct osmo_it_msgq *_osmo_it_msgq_by_name(const char *name) +{ + struct osmo_it_msgq *q; + llist_for_each_entry(q, &msg_queues, entry) { + if (!strcmp(q->name, name)) + return q; + } + return NULL; +} + +struct osmo_it_msgq *osmo_it_msgq_by_name(const char *name) +{ + struct osmo_it_msgq *q; + pthread_rwlock_rdlock(&msg_queues_rwlock); + q = _osmo_it_msgq_by_name(name); + pthread_rwlock_unlock(&msg_queues_rwlock); + return q; +} + +/* osmo_fd call-back when eventfd is readable */ +static int osmo_it_msgq_fd_cb(struct osmo_fd *ofd, unsigned int what) +{ + struct osmo_it_msgq *q = (struct osmo_it_msgq *) ofd->data; + uint64_t val; + int i, rc; + + if (!(what & OSMO_FD_READ)) + return 0; + + rc = read(ofd->fd, &val, sizeof(val)); + if (rc < sizeof(val)) + return rc; + + for (i = 0; i < val; i++) { + struct msgb *msg = osmo_it_msgq_dequeue(q); + /* in case the user might have called osmo_it_msgq_flush() we may + * end up in the eventfd-dispatch but witout any messages left in the queue, + * otherwise I'd have loved to OSMO_ASSERT(msg) here. */ + if (!msg) + break; + q->read_cb(q, msg); + } + + return 0; +} + +/*! Allocate a new inter-thread message queue. + * \param[in] ctx talloc context from which to allocate the queue + * \param[in] name human-readable string name of the queue; function creates a copy. + * \param[in] read_cb call-back function to be called for each de-queued message + * \returns a newly-allocated inter-thread message queue; NULL in case of error */ +struct osmo_it_msgq *osmo_it_msgq_alloc(void *ctx, const char *name, unsigned int max_length, + void (*read_cb)(struct osmo_it_msgq *q, struct msgb *msg), + void *data) +{ + struct osmo_it_msgq *q; + int fd; + + q = talloc_zero(ctx, struct osmo_it_msgq); + if (!q) + return NULL; + q->data = data; + q->name = talloc_strdup(q, name); + q->current_length = 0; + q->max_length = max_length; + q->read_cb = read_cb; + INIT_LLIST_HEAD(&q->list); + + /* create eventfd */ + fd = eventfd(0, 0); + if (fd < 0) { + talloc_free(q); + return NULL; + } + + /* initialize BUT NOT REGISTER the osmo_fd. The receiving thread must + * take are to select/poll/read/... on ot */ + osmo_fd_setup(&q->event_ofd, fd, OSMO_FD_READ, osmo_it_msgq_fd_cb, q, 0); + + /* add to global list of queues, checking for duplicate names */ + pthread_rwlock_wrlock(&msg_queues_rwlock); + if (_osmo_it_msgq_by_name(q->name)) { + pthread_rwlock_unlock(&msg_queues_rwlock); + osmo_fd_close(&q->event_ofd); + talloc_free(q); + return NULL; + } + llist_add_tail(&q->entry, &msg_queues); + pthread_rwlock_unlock(&msg_queues_rwlock); + + return q; +} + +/*! Flush all messages currently present in queue */ +static void _osmo_it_msgq_flush(struct osmo_it_msgq *q) +{ + struct msgb *msg; + while ((msg = msgb_dequeue_count(&q->list, &q->current_length))) { + msgb_free(msg); + } +} + +/*! Flush all messages currently present in queue */ +void osmo_it_msgq_flush(struct osmo_it_msgq *q) +{ + pthread_mutex_lock(&q->mutex); + _osmo_it_msgq_flush(q); + pthread_mutex_unlock(&q->mutex); +} + +/*! Destroy a message queue */ +void osmo_it_msgq_destroy(struct osmo_it_msgq *q) +{ + /* first remove from global list of queues */ + pthread_rwlock_wrlock(&msg_queues_rwlock); + llist_del(&q->entry); + pthread_rwlock_unlock(&msg_queues_rwlock); + /* next, close the eventfd */ + osmo_fd_close(&q->event_ofd); + /* flush all messages still present */ + osmo_it_msgq_flush(q); + /* and finally release memory */ + talloc_free(q); +} + +/*! Thread-safe en-queue to an inter-thread message queue. + * \param[in] queue Inter-thread queue on which to enqueue + * \param[in] msgb Message buffer to enqueue + * \returns 0 on success; negative on error */ +int osmo_it_msgq_enqueue(struct osmo_it_msgq *queue, struct msgb *msg) +{ + pthread_mutex_lock(&queue->mutex); + if (queue->current_length+1 > queue->max_length) { + pthread_mutex_unlock(&queue->mutex); + return -ENOSPC; + } + msgb_enqueue_count(&queue->list, msg, &queue->current_length); + pthread_mutex_unlock(&queue->mutex); + /* increment eventfd counter by one */ + eventfd_increment(queue->event_ofd.fd, 1); + return 0; +} + +/*! Thread-safe de-queue from an inter-thread message queue. + * \param[in] queue Inter-thread queue from which to dequeue + * \returns dequeued message buffer; NULL if none available + */ +struct msgb *osmo_it_msgq_dequeue(struct osmo_it_msgq *queue) +{ + struct msgb *msg; + + pthread_mutex_lock(&queue->mutex); + msg = msgb_dequeue_count(&queue->list, &queue->current_length); + pthread_mutex_unlock(&queue->mutex); + + return msg; +} + +#endif /* HAVE_SYS_EVENTFD_H */ + +/*! @} */ diff --git a/tests/Makefile.am b/tests/Makefile.am index 92edf752..9ea20248 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -32,7 +32,7 @@ check_PROGRAMS = timer/timer_test sms/sms_test ussd/ussd_test \ tdef/tdef_vty_test_dynamic \ sockaddr_str/sockaddr_str_test \ use_count/use_count_test \ - context/context_test \ + context/context_test it_msgq/it_msgq_test \ $(NULL) if ENABLE_MSGFILE @@ -255,6 +255,10 @@ use_count_use_count_test_LDADD = $(LDADD) context_context_test_SOURCES = context/context_test.c context_context_test_LDADD = $(LDADD) + +it_msgq_it_msgq_test_SOURCES = it_msgq/it_msgq_test.c +it_msgq_it_msgq_test_LDADD = $(LDADD) + # The `:;' works around a Bash 3.2 bug when the output is not writeable. $(srcdir)/package.m4: $(top_srcdir)/configure.ac :;{ \ @@ -327,6 +331,7 @@ EXTRA_DIST = testsuite.at $(srcdir)/package.m4 $(TESTSUITE) \ sockaddr_str/sockaddr_str_test.ok \ use_count/use_count_test.ok use_count/use_count_test.err \ context/context_test.ok \ + it_msgq/it_msgq_test.ok \ $(NULL) DISTCLEANFILES = atconfig atlocal conv/gsm0503_test_vectors.c diff --git a/tests/it_msgq/it_msgq_test.c b/tests/it_msgq/it_msgq_test.c new file mode 100644 index 00000000..943bc662 --- /dev/null +++ b/tests/it_msgq/it_msgq_test.c @@ -0,0 +1,106 @@ +#include +#include + +#include +#include + +#define ENTER_TC printf("\n== Entering test case %s\n", __func__) + +static void tc_alloc(void) +{ + struct osmo_it_msgq *q1, *q2; + + ENTER_TC; + + printf("allocating q1\n"); + q1 = osmo_it_msgq_alloc(OTC_GLOBAL, "q1", 3, NULL, NULL); + OSMO_ASSERT(q1); + + /* ensure that no duplicate allocation for the */ + printf("attempting duplicate allocation of qa\n"); + q2 = osmo_it_msgq_alloc(OTC_GLOBAL, "q1", 3, NULL, NULL); + OSMO_ASSERT(!q2); + + /* ensure that same name can be re-created after destroying old one */ + osmo_it_msgq_destroy(q1); + printf("re-allocating q1\n"); + q1 = osmo_it_msgq_alloc(OTC_GLOBAL, "q1", 3, NULL, NULL); + OSMO_ASSERT(q1); + + osmo_it_msgq_destroy(q1); +} + +static void tc_queue_length(void) +{ + struct osmo_it_msgq *q1; + unsigned int qlen = 3; + struct msgb *msg; + int i, rc; + + ENTER_TC; + + printf("allocating q1\n"); + q1 = osmo_it_msgq_alloc(OTC_GLOBAL, "q1", qlen, NULL, NULL); + OSMO_ASSERT(q1); + + printf("adding queue entries up to the limit\n"); + for (i = 0; i < qlen; i++) { + msg = msgb_alloc(23, __func__); + rc = osmo_it_msgq_enqueue(q1, msg); + OSMO_ASSERT(rc == 0); + } + printf("attempting to add more than the limit\n"); + msg = msgb_alloc(23, __func__); + rc = osmo_it_msgq_enqueue(q1, msg); + OSMO_ASSERT(rc == -ENOSPC); + + osmo_it_msgq_destroy(q1); +} + +static int g_read_cb_count; + +static void q_read_cb(struct osmo_it_msgq *q, struct msgb *msg) +{ + g_read_cb_count++; + talloc_free(msg); +} + +static void tc_eventfd(void) +{ + struct osmo_it_msgq *q1; + unsigned int qlen = 30; + struct msgb *msg; + int i, rc; + + ENTER_TC; + + printf("allocating q1\n"); + q1 = osmo_it_msgq_alloc(OTC_GLOBAL, "q1", qlen, q_read_cb, NULL); + OSMO_ASSERT(q1); + osmo_fd_register(&q1->event_ofd); + + /* ensure read-cb isn't called unless we enqueue something */ + osmo_select_main(1); + OSMO_ASSERT(g_read_cb_count == 0); + + /* ensure read-cb is called for each enqueued msg once */ + printf("adding %u queue entries up to the limit\n", qlen); + for (i = 0; i < qlen; i++) { + msg = msgb_alloc(23, __func__); + rc = osmo_it_msgq_enqueue(q1, msg); + OSMO_ASSERT(rc == 0); + } + + osmo_select_main(1); + printf("%u entries were dequeued\n", qlen); + OSMO_ASSERT(g_read_cb_count == qlen); + + osmo_it_msgq_destroy(q1); +} + +int main(int argc, char **argv) +{ + tc_alloc(); + tc_queue_length(); + tc_eventfd(); +} diff --git a/tests/it_msgq/it_msgq_test.ok b/tests/it_msgq/it_msgq_test.ok new file mode 100644 index 00000000..7f102c61 --- /dev/null +++ b/tests/it_msgq/it_msgq_test.ok @@ -0,0 +1,15 @@ + +== Entering test case tc_alloc +allocating q1 +attempting duplicate allocation of qa +re-allocating q1 + +== Entering test case tc_queue_length +allocating q1 +adding queue entries up to the limit +attempting to add more than the limit + +== Entering test case tc_eventfd +allocating q1 +adding 30 queue entries up to the limit +30 entries were dequeued diff --git a/tests/testsuite.at b/tests/testsuite.at index a043f0c7..19cd2af8 100644 --- a/tests/testsuite.at +++ b/tests/testsuite.at @@ -356,3 +356,9 @@ AT_KEYWORDS([context]) cat $abs_srcdir/context/context_test.ok > expout AT_CHECK([$abs_top_builddir/tests/context/context_test], [0], [expout], [ignore]) AT_CLEANUP + +AT_SETUP([it_msgq]) +AT_KEYWORDS([it_msgq]) +cat $abs_srcdir/it_msgq/it_msgq_test.ok > expout +AT_CHECK([$abs_top_builddir/tests/it_msgq/it_msgq_test], [0], [expout], [ignore]) +AT_CLEANUP -- cgit v1.2.3