/* * Ouroboros - Copyright (C) 2016 * * Ring buffer for application processes * * Dimitri Staessens <dimitri.staessens@intec.ugent.be> * * 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <ouroboros/shm_ap_rbuff.h> #define OUROBOROS_PREFIX "shm_ap_rbuff" #include <ouroboros/logs.h> #include <pthread.h> #include <sys/mman.h> #include <fcntl.h> #include <stdlib.h> #include <string.h> #include <stdint.h> #include <unistd.h> #include <stdbool.h> #include <errno.h> #define SHM_RBUFF_FILE_SIZE (SHM_RBUFF_SIZE * sizeof(struct rb_entry) \ + 2 * sizeof(size_t) + sizeof(pthread_mutex_t)) #define shm_rbuff_used(rb)((*rb->ptr_head + SHM_RBUFF_SIZE - *rb->ptr_tail)\ & (SHM_RBUFF_SIZE - 1)) #define shm_rbuff_free(rb)(shm_rbuff_used(rb) + 1 < SHM_RBUFF_SIZE) struct shm_ap_rbuff { struct rb_entry * shm_base; /* start of entry */ size_t * ptr_head; /* start of ringbuffer head */ size_t * ptr_tail; /* start of ringbuffer tail */ pthread_mutex_t * shm_mutex; /* lock all free space in shm */ pid_t pid; /* pid to which this rb belongs */ int fd; }; struct shm_ap_rbuff * shm_ap_rbuff_create() { struct shm_ap_rbuff * rb; int shm_fd; struct rb_entry * shm_base; pthread_mutexattr_t attr; char fn[25]; sprintf(fn, SHM_AP_RBUFF_PREFIX "%d", getpid()); rb = malloc(sizeof(*rb)); if (rb == NULL) { LOG_DBGF("Could not allocate struct."); return NULL; } shm_fd = shm_open(fn, O_CREAT | O_EXCL | O_RDWR, 0666); if (shm_fd == -1) { LOG_DBGF("Failed creating ring buffer."); free(rb); return NULL; } if (lseek(shm_fd, SHM_RBUFF_FILE_SIZE - 1, SEEK_SET) < 0) { LOG_DBGF("Failed to extend ringbuffer."); free(rb); return NULL; } if (write(shm_fd, "", 1) != 1) { LOG_DBGF("Failed to finalise extension of ringbuffer."); free(rb); return NULL; } shm_base = mmap(NULL, SHM_RBUFF_FILE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0); if (shm_base == MAP_FAILED) { LOG_DBGF("Failed to map shared memory."); if (close(shm_fd) == -1) LOG_DBGF("Failed to close invalid shm."); if (shm_unlink(fn) == -1) LOG_DBGF("Failed to remove invalid shm."); free(rb); return NULL; } rb->shm_base = shm_base; rb->ptr_head = (size_t *) (rb->shm_base + SHM_RBUFF_SIZE); rb->ptr_tail = (size_t *) ((uint8_t *) rb->ptr_head + sizeof(size_t)); rb->shm_mutex = (pthread_mutex_t *) ((uint8_t *) rb->ptr_tail + sizeof(size_t)); pthread_mutexattr_init(&attr); pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED); pthread_mutex_init(rb->shm_mutex, &attr); *rb->ptr_head = 0; *rb->ptr_tail = 0; rb->fd = shm_fd; rb->pid = getpid(); return rb; } struct shm_ap_rbuff * shm_ap_rbuff_open(pid_t pid) { struct shm_ap_rbuff * rb; int shm_fd; struct rb_entry * shm_base; char fn[25]; sprintf(fn, SHM_AP_RBUFF_PREFIX "%d", pid); rb = malloc(sizeof(*rb)); if (rb == NULL) { LOG_DBGF("Could not allocate struct."); return NULL; } shm_fd = shm_open(fn, O_RDWR, 0666); if (shm_fd == -1) { LOG_DBGF("Failed opening shared memory %s.", fn); return NULL; } shm_base = mmap(NULL, SHM_RBUFF_FILE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0); if (shm_base == MAP_FAILED) { LOG_DBGF("Failed to map shared memory."); if (close(shm_fd) == -1) LOG_DBGF("Failed to close invalid shm."); if (shm_unlink(fn) == -1) LOG_DBGF("Failed to remove invalid shm."); free(rb); return NULL; } rb->shm_base = shm_base; rb->ptr_head = (size_t *) (rb->shm_base + SHM_RBUFF_SIZE); rb->ptr_tail = (size_t *) ((uint8_t *) rb->ptr_head + sizeof(size_t)); rb->shm_mutex = (pthread_mutex_t *) ((uint8_t *) rb->ptr_tail + sizeof(size_t)); rb->fd = shm_fd; rb->pid = pid; return rb; } void shm_ap_rbuff_close(struct shm_ap_rbuff * rb) { if (rb == NULL) { LOG_DBGF("Bogus input. Bugging out."); return; } if (munmap(rb->shm_base, SHM_RBUFF_FILE_SIZE) == -1) LOG_DBGF("Couldn't unmap shared memory."); free(rb); } void shm_ap_rbuff_destroy(struct shm_ap_rbuff * rb) { char fn[25]; if (rb == NULL) { LOG_DBGF("Bogus input. Bugging out."); return; } if (rb->pid != getpid()) { LOG_ERR("Tried to destroy other AP's rbuff."); return; } sprintf(fn, SHM_AP_RBUFF_PREFIX "%d", rb->pid); if (munmap(rb->shm_base, SHM_RBUFF_FILE_SIZE) == -1) LOG_DBGF("Couldn't unmap shared memory."); if (shm_unlink(fn) == -1) LOG_DBGF("Failed to unlink shm."); free(rb); } int shm_ap_rbuff_write(struct shm_ap_rbuff * rb, struct rb_entry * e) { struct rb_entry * pos; if (rb == NULL || e == NULL) return -1; pthread_mutex_lock(rb->shm_mutex); if (!shm_rbuff_free(rb)) { pthread_mutex_unlock(rb->shm_mutex); return -1; } pos = rb->shm_base + *rb->ptr_head; *pos = *e; *rb->ptr_head = (*rb->ptr_head + 1) & (SHM_RBUFF_SIZE -1); pthread_mutex_unlock(rb->shm_mutex); return 0; } struct rb_entry * shm_ap_rbuff_read(struct shm_ap_rbuff * rb) { struct rb_entry * e = NULL; if (rb == NULL) return NULL; pthread_mutex_lock(rb->shm_mutex); if (shm_rbuff_used(rb) == 0) { pthread_mutex_unlock(rb->shm_mutex); return NULL; } e = malloc(sizeof(*e)); if (e == NULL) { pthread_mutex_unlock(rb->shm_mutex); return NULL; } *e = *(rb->shm_base + *rb->ptr_tail); *rb->ptr_tail = (*rb->ptr_tail + 1) & (SHM_RBUFF_SIZE -1); pthread_mutex_unlock(rb->shm_mutex); return e; }