+void *consumer_thread(void *arg)
+{
+ struct buffer_info *buf = (struct buffer_info *) arg;
+ int result;
+
+ for(;;) {
+ /* get the subbuffer */
+ result = get_subbuffer(buf);
+ if(result == -1) {
+ ERR("error getting subbuffer");
+ continue;
+ }
+ else if(result == GET_SUBBUF_DONE) {
+ /* this is done */
+ break;
+ }
+ else if(result == GET_SUBBUF_DIED) {
+ finish_consuming_dead_subbuffer(buf);
+ break;
+ }
+
+ /* write data to file */
+ result = patient_write(buf->file_fd, buf->mem + (buf->consumed_old & (buf->n_subbufs * buf->subbuf_size-1)), buf->subbuf_size);
+ if(result == -1) {
+ PERROR("write");
+ /* FIXME: maybe drop this trace */
+ }
+
+ /* put the subbuffer */
+ result = put_subbuffer(buf);
+ if(result == -1) {
+ ERR("unknown error putting subbuffer (channel=%s)", buf->name);
+ break;
+ }
+ else if(result == PUT_SUBBUF_PUSHED) {
+ ERR("Buffer overflow (channel=%s), reader pushed. This channel will not be usable passed this point.", buf->name);
+ break;
+ }
+ else if(result == PUT_SUBBUF_DIED) {
+ WARN("application died while putting subbuffer");
+ /* FIXME: probably need to skip the first subbuffer in finish_consuming_dead_subbuffer */
+ finish_consuming_dead_subbuffer(buf);
+ }
+ else if(result == PUT_SUBBUF_OK) {
+ }
+ }
+
+ DBG("thread for buffer %s is stopping", buf->name);
+
+ /* FIXME: destroy, unalloc... */
+
+ return NULL;
+}
+
+int add_buffer(pid_t pid, char *bufname)
+{
+ struct buffer_info *buf;
+ char *send_msg;
+ char *received_msg;
+ int result;
+ char *tmp;
+ int fd;
+ pthread_t thr;
+ struct shmid_ds shmds;
+
+ buf = (struct buffer_info *) malloc(sizeof(struct buffer_info));
+ if(buf == NULL) {
+ ERR("add_buffer: insufficient memory");
+ return -1;
+ }
+
+ buf->name = bufname;
+ buf->pid = pid;
+
+ /* connect to app */
+ result = ustcomm_connect_app(buf->pid, &buf->conn);
+ if(result) {
+ WARN("unable to connect to process, it probably died before we were able to connect");
+ return -1;
+ }
+
+ /* get shmid */
+ asprintf(&send_msg, "get_shmid %s", buf->name);
+ result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
+ free(send_msg);
+ if(result == -1) {
+ ERR("problem in ustcomm_send_request(get_shmid)");
+ return -1;
+ }
+
+ result = sscanf(received_msg, "%d %d", &buf->shmid, &buf->bufstruct_shmid);
+ if(result != 2) {
+ ERR("unable to parse response to get_shmid");
+ return -1;
+ }
+ free(received_msg);
+ DBG("got shmids %d %d", buf->shmid, buf->bufstruct_shmid);
+
+ /* get n_subbufs */
+ asprintf(&send_msg, "get_n_subbufs %s", buf->name);
+ result = ustcomm_send_request(&buf->conn, send_msg, &received_msg);
+ free(send_msg);
+ if(result == -1) {
+ ERR("problem in ustcomm_send_request(g_n_subbufs)");
+ return -1;
+ }
+
+ result = sscanf(received_msg, "%d", &buf->n_subbufs);
+ if(result != 1) {
+ ERR("unable to parse response to get_n_subbufs");
+ return -1;
+ }
+ free(received_msg);
+ DBG("got n_subbufs %d", buf->n_subbufs);
+
+ /* get subbuf size */
+ asprintf(&send_msg, "get_subbuf_size %s", buf->name);
+ ustcomm_send_request(&buf->conn, send_msg, &received_msg);
+ free(send_msg);
+
+ result = sscanf(received_msg, "%d", &buf->subbuf_size);
+ if(result != 1) {
+ ERR("unable to parse response to get_subbuf_size");
+ return -1;
+ }
+ free(received_msg);
+ DBG("got subbuf_size %d", buf->subbuf_size);
+
+ /* attach memory */
+ buf->mem = shmat(buf->shmid, NULL, 0);
+ if(buf->mem == (void *) 0) {
+ perror("shmat");
+ return -1;
+ }
+ DBG("successfully attached buffer memory");
+
+ buf->bufstruct_mem = shmat(buf->bufstruct_shmid, NULL, 0);
+ if(buf->bufstruct_mem == (void *) 0) {
+ perror("shmat");
+ return -1;
+ }
+ DBG("successfully attached buffer bufstruct memory");
+
+ /* obtain info on the memory segment */
+ result = shmctl(buf->shmid, IPC_STAT, &shmds);
+ if(result == -1) {
+ perror("shmctl");
+ return -1;
+ }
+ buf->memlen = shmds.shm_segsz;
+
+ /* open file for output */
+ asprintf(&tmp, "/tmp/trace/%s_0", buf->name);
+ result = fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC, 00600);
+ if(result == -1) {
+ PERROR("open");
+ ERR("failed opening trace file %s", tmp);
+ return -1;
+ }
+ buf->file_fd = fd;
+ free(tmp);
+
+ pthread_create(&thr, NULL, consumer_thread, buf);
+
+ return 0;
+}
+