/* * 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., http://www.fsf.org/about/contact/. */ #include "config.h" #include <ouroboros/shm_rbuff.h> #include <ouroboros/lockfile.h> #include <ouroboros/time_utils.h> #include <ouroboros/errno.h> #include <ouroboros/fccntl.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 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); #ifdef HAVE_ROBUST_MUTEX 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 = ACL_RDWR; *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; bool was_empty = false; assert(rb); assert(idx < SHM_BUFFER_SIZE); if (__sync_fetch_and_add(rb->acl, 0) != ACL_RDWR) { if (__sync_fetch_and_add(rb->acl, 0) & ACL_FLOWDOWN) return -EFLOWDOWN; else if (__sync_fetch_and_add(rb->acl, 0) & ACL_RDONLY) return -ENOTALLOC; } if (!shm_rbuff_free(rb)) return -EAGAIN; if (shm_rbuff_empty(rb)) was_empty = true; nhead = RB_HEAD; *(rb->shm_base + nhead) = (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); if (was_empty) pthread_cond_broadcast(rb->add); 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 __sync_fetch_and_add(rb->acl, 0) & ACL_FLOWDOWN ? -EFLOWDOWN : -EAGAIN; ntail = 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 *(rb->shm_base + ntail); } ssize_t shm_rbuff_read_b(struct shm_rbuff * rb, const 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; #ifndef HAVE_ROBUST_MUTEX 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 (abstime != NULL) idx = -pthread_cond_timedwait(rb->add, rb->lock, abstime); else idx = -pthread_cond_wait(rb->add, rb->lock); #ifdef HAVE_ROBUST_MUTEX 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_set_acl(struct shm_rbuff * rb, uint32_t flags) { assert(rb); __sync_bool_compare_and_swap(rb->acl, *rb->acl, flags); } uint32_t shm_rbuff_get_acl(struct shm_rbuff * rb) { assert(rb); return __sync_fetch_and_add(rb->acl, 0); } void shm_rbuff_fini(struct shm_rbuff * rb) { assert(rb); if (shm_rbuff_empty(rb)) return; #ifndef HAVE_ROBUST_MUTEX 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)) #ifndef HAVE_ROBUST_MUTEX 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); }