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-rw-r--r--src/lib/shm_rbuff_ll.c379
1 files changed, 379 insertions, 0 deletions
diff --git a/src/lib/shm_rbuff_ll.c b/src/lib/shm_rbuff_ll.c
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+++ b/src/lib/shm_rbuff_ll.c
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+/*
+ * Ouroboros - Copyright (C) 2016 - 2017
+ *
+ * Lockless ring buffer for incoming SDUs
+ *
+ * Dimitri Staessens <dimitri.staessens@ugent.be>
+ * Sander Vrijders <sander.vrijders@ugent.be>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include <ouroboros/config.h>
+#include <ouroboros/shm_rbuff.h>
+#include <ouroboros/lockfile.h>
+#include <ouroboros/time_utils.h>
+#include <ouroboros/errno.h>
+
+#include <pthread.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/stat.h>
+#include <assert.h>
+#include <stdbool.h>
+
+#define FN_MAX_CHARS 255
+#define RB_OPEN 0
+#define RB_CLOSED 1
+
+#define SHM_RBUFF_FILE_SIZE ((SHM_BUFFER_SIZE) * sizeof(ssize_t) \
+ + 3 * sizeof(size_t) \
+ + sizeof(pthread_mutex_t) \
+ + 2 * sizeof (pthread_cond_t))
+
+#define RB_HEAD __sync_fetch_and_add(rb->head, 0)
+#define RB_TAIL __sync_fetch_and_add(rb->tail, 0)
+
+#define shm_rbuff_used(rb) ((RB_HEAD + (SHM_BUFFER_SIZE) - RB_TAIL) \
+ & ((SHM_BUFFER_SIZE) - 1))
+#define shm_rbuff_free(rb) (shm_rbuff_used(rb) + 1 < (SHM_BUFFER_SIZE))
+#define shm_rbuff_empty(rb) (RB_HEAD == RB_TAIL)
+#define head_el_ptr(rb) (rb->shm_base + RB_HEAD)
+#define tail_el_ptr(rb) (rb->shm_base + RB_TAIL)
+
+struct shm_rbuff {
+ ssize_t * shm_base; /* start of entry */
+ size_t * head; /* start of ringbuffer head */
+ size_t * tail; /* start of ringbuffer tail */
+ size_t * acl; /* access control */
+ pthread_mutex_t * lock; /* lock all free space in shm */
+ pthread_cond_t * add; /* SDU arrived */
+ pthread_cond_t * del; /* SDU removed */
+ pid_t api; /* api of the owner */
+ int port_id; /* port_id of the flow */
+};
+
+struct shm_rbuff * shm_rbuff_create(pid_t api, int port_id)
+{
+ struct shm_rbuff * rb;
+ int shm_fd;
+ ssize_t * shm_base;
+ pthread_mutexattr_t mattr;
+ pthread_condattr_t cattr;
+ char fn[FN_MAX_CHARS];
+ mode_t mask;
+
+ sprintf(fn, SHM_RBUFF_PREFIX "%d.%d", api, port_id);
+
+ rb = malloc(sizeof(*rb));
+ if (rb == NULL)
+ return NULL;
+
+ mask = umask(0);
+
+ shm_fd = shm_open(fn, O_CREAT | O_EXCL | O_RDWR, 0666);
+ if (shm_fd == -1) {
+ free(rb);
+ return NULL;
+ }
+
+ umask(mask);
+
+ if (ftruncate(shm_fd, SHM_RBUFF_FILE_SIZE - 1) < 0) {
+ free(rb);
+ close(shm_fd);
+ return NULL;
+ }
+
+ shm_base = mmap(NULL,
+ SHM_RBUFF_FILE_SIZE,
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED,
+ shm_fd,
+ 0);
+
+ close(shm_fd);
+
+ if (shm_base == MAP_FAILED) {
+ shm_unlink(fn);
+ free(rb);
+ return NULL;
+ }
+
+ rb->shm_base = shm_base;
+ rb->head = (size_t *) (rb->shm_base + (SHM_BUFFER_SIZE));
+ rb->tail = rb->head + 1;
+ rb->acl = rb->tail + 1;
+ rb->lock = (pthread_mutex_t *) (rb->acl + 1);
+ rb->add = (pthread_cond_t *) (rb->lock + 1);
+ rb->del = rb->add + 1;
+
+ pthread_mutexattr_init(&mattr);
+#ifndef __APPLE__
+ pthread_mutexattr_setrobust(&mattr, PTHREAD_MUTEX_ROBUST);
+#endif
+ pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
+ pthread_mutex_init(rb->lock, &mattr);
+
+ pthread_condattr_init(&cattr);
+ pthread_condattr_setpshared(&cattr, PTHREAD_PROCESS_SHARED);
+#ifndef __APPLE__
+ pthread_condattr_setclock(&cattr, PTHREAD_COND_CLOCK);
+#endif
+ pthread_cond_init(rb->add, &cattr);
+ pthread_cond_init(rb->del, &cattr);
+
+ *rb->acl = RB_OPEN;
+ *rb->head = 0;
+ *rb->tail = 0;
+
+ rb->api = api;
+ rb->port_id = port_id;
+
+ return rb;
+}
+
+struct shm_rbuff * shm_rbuff_open(pid_t api, int port_id)
+{
+ struct shm_rbuff * rb;
+ int shm_fd;
+ ssize_t * shm_base;
+ char fn[FN_MAX_CHARS];
+
+ sprintf(fn, SHM_RBUFF_PREFIX "%d.%d", api, port_id);
+
+ rb = malloc(sizeof(*rb));
+ if (rb == NULL)
+ return NULL;
+
+ shm_fd = shm_open(fn, O_RDWR, 0666);
+ if (shm_fd == -1) {
+ free(rb);
+ return NULL;
+ }
+
+ shm_base = mmap(NULL,
+ SHM_RBUFF_FILE_SIZE,
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED,
+ shm_fd,
+ 0);
+
+ close(shm_fd);
+
+ if (shm_base == MAP_FAILED) {
+ shm_unlink(fn);
+ free(rb);
+ return NULL;
+ }
+
+ rb->shm_base = shm_base;
+ rb->head = (size_t *) (rb->shm_base + (SHM_BUFFER_SIZE));
+ rb->tail = rb->head + 1;
+ rb->acl = rb->tail + 1;
+ rb->lock = (pthread_mutex_t *) (rb->acl + 1);
+ rb->add = (pthread_cond_t *) (rb->lock + 1);
+ rb->del = rb->add + 1;
+
+ rb->api = api;
+ rb->port_id = port_id;
+
+ return rb;
+}
+
+void shm_rbuff_close(struct shm_rbuff * rb)
+{
+ assert(rb);
+
+ munmap(rb->shm_base, SHM_RBUFF_FILE_SIZE);
+
+ free(rb);
+}
+
+void shm_rbuff_destroy(struct shm_rbuff * rb)
+{
+ char fn[FN_MAX_CHARS];
+
+ assert(rb);
+
+ sprintf(fn, SHM_RBUFF_PREFIX "%d.%d", rb->api, rb->port_id);
+
+ munmap(rb->shm_base, SHM_RBUFF_FILE_SIZE);
+ shm_unlink(fn);
+
+ free(rb);
+}
+
+int shm_rbuff_write(struct shm_rbuff * rb,
+ size_t idx)
+{
+ size_t ohead;
+ size_t nhead;
+
+ assert(rb);
+ assert(idx < SHM_BUFFER_SIZE);
+
+ if (__sync_fetch_and_add(rb->acl, 0)) /* CLOSED */
+ return -ENOTALLOC;
+
+ if (!shm_rbuff_free(rb))
+ return -EAGAIN;
+
+ if (shm_rbuff_empty(rb))
+ pthread_cond_broadcast(rb->add);
+
+ ohead = RB_HEAD;
+
+ *head_el_ptr(rb) = (ssize_t) idx;
+
+ do {
+ ohead = nhead;
+ nhead = (ohead + 1) & ((SHM_BUFFER_SIZE) - 1);
+ nhead = __sync_val_compare_and_swap(rb->head, ohead, nhead);
+ } while (nhead != ohead);
+
+ return 0;
+}
+
+ssize_t shm_rbuff_read(struct shm_rbuff * rb)
+{
+ size_t otail;
+ size_t ntail;
+
+ assert(rb);
+
+ if (shm_rbuff_empty(rb))
+ return -EAGAIN;
+
+ otail = RB_TAIL;
+
+ do {
+ otail = ntail;
+ ntail = (otail + 1) & ((SHM_BUFFER_SIZE) - 1);
+ ntail = __sync_val_compare_and_swap(rb->tail, otail, ntail);
+ } while (ntail != otail);
+
+ pthread_cond_broadcast(rb->del);
+
+ return *tail_el_ptr(rb);
+}
+
+ssize_t shm_rbuff_read_b(struct shm_rbuff * rb,
+ const struct timespec * timeout)
+{
+ struct timespec abstime;
+ ssize_t idx = -1;
+
+ assert(rb);
+
+ /* try a non-blocking read first */
+ idx = shm_rbuff_read(rb);
+ if (idx != -EAGAIN)
+ return idx;
+
+ if (timeout != NULL) {
+ clock_gettime(PTHREAD_COND_CLOCK, &abstime);
+ ts_add(&abstime, timeout, &abstime);
+ }
+
+#ifdef __APPLE__
+ pthread_mutex_lock(rb->lock);
+#else
+ if (pthread_mutex_lock(rb->lock) == EOWNERDEAD)
+ pthread_mutex_consistent(rb->lock);
+#endif
+ pthread_cleanup_push((void(*)(void *))pthread_mutex_unlock,
+ (void *) rb->lock);
+
+ while (shm_rbuff_empty(rb) && (idx != -ETIMEDOUT)) {
+ if (timeout != NULL)
+ idx = -pthread_cond_timedwait(rb->add,
+ rb->lock,
+ &abstime);
+ else
+ idx = -pthread_cond_wait(rb->add, rb->lock);
+#ifndef __APPLE__
+ if (idx == -EOWNERDEAD)
+ pthread_mutex_consistent(rb->lock);
+#endif
+ }
+
+ if (idx != -ETIMEDOUT) {
+ /* do a nonblocking read */
+ idx = shm_rbuff_read(rb);
+
+ assert(idx >= 0);
+ }
+
+ pthread_cleanup_pop(true);
+
+ return idx;
+}
+
+void shm_rbuff_block(struct shm_rbuff * rb)
+{
+ assert(rb);
+
+ __sync_bool_compare_and_swap(rb->acl, RB_OPEN, RB_CLOSED);
+}
+
+void shm_rbuff_unblock(struct shm_rbuff * rb)
+{
+ assert(rb);
+
+ __sync_bool_compare_and_swap(rb->acl, RB_CLOSED, RB_OPEN);
+}
+
+void shm_rbuff_fini(struct shm_rbuff * rb)
+{
+ assert(rb);
+
+ assert(__sync_fetch_and_add(rb->acl, 0) == RB_CLOSED);
+
+ if (shm_rbuff_empty)
+ return;
+
+#ifdef __APPLE__
+ pthread_mutex_lock(rb->lock);
+#else
+ if (pthread_mutex_lock(rb->lock) == EOWNERDEAD)
+ pthread_mutex_consistent(rb->lock);
+#endif
+
+ pthread_cleanup_push((void(*)(void *))pthread_mutex_unlock,
+ (void *) rb->lock);
+
+ while (!shm_rbuff_empty(rb))
+#ifdef __APPLE__
+ pthread_cond_wait(rb->del, rb->lock);
+#else
+ if (pthread_cond_wait(rb->del, rb->lock) == EOWNERDEAD)
+ pthread_mutex_consistent(rb->lock);
+#endif
+ pthread_cleanup_pop(true);
+}
+
+size_t shm_rbuff_queued(struct shm_rbuff * rb)
+{
+ assert(rb);
+
+ return shm_rbuff_used(rb);
+}
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