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-rw-r--r--src/lib/shm_ap_rbuff.c268
1 files changed, 268 insertions, 0 deletions
diff --git a/src/lib/shm_ap_rbuff.c b/src/lib/shm_ap_rbuff.c
new file mode 100644
index 00000000..4bd64775
--- /dev/null
+++ b/src/lib/shm_ap_rbuff.c
@@ -0,0 +1,268 @@
+/*
+ * Ouroboros - Copyright (C) 2016
+ *
+ * Ring buffer for application processes
+ *
+ * Dimitri Staessens <[email protected]>
+ *
+ * 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 "%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 "%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)
+{
+ char fn[25];
+
+ if (rb == NULL) {
+ LOG_DBGF("Bogus input. Bugging out.");
+ return;
+ }
+
+ sprintf(fn, SHM_AP_RBUFF "%d", rb->pid);
+
+ 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 "%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 = malloc(sizeof(*e));
+ if (e == NULL)
+ return 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 = *(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;
+}
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