+/*
+ * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
+ * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <poll.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <urcu/list.h>
+
+#include "libkernelctl.h"
+#include "liblttkconsumerd.h"
+#include "lttngerr.h"
+
+/* Init the list of FDs */
+static struct kconsumerd_fd_list kconsumerd_fd_list = {
+ .head = CDS_LIST_HEAD_INIT(kconsumerd_fd_list.head),
+};
+
+/* Number of element for the list below. */
+static unsigned int kconsumerd_fds_count;
+
+/* If the local array of FDs needs update in the poll function */
+static unsigned int kconsumerd_update_fd_array = 1;
+
+/* lock the fd array and structures */
+static pthread_mutex_t kconsumerd_lock_fds;
+
+/* communication with splice */
+static int kconsumerd_thread_pipe[2];
+
+/* pipe to wake the poll thread when necessary */
+static int kconsumerd_poll_pipe[2];
+
+/* timeout parameter, to control the polling thread grace period */
+static int kconsumerd_poll_timeout = -1;
+
+/* socket to communicate errors with sessiond */
+static int kconsumerd_error_socket;
+
+/* socket to exchange commands with sessiond */
+static char *kconsumerd_command_sock_path;
+
+/* flag to inform the polling thread to kconsumerd_quit when all fd hung up */
+static int kconsumerd_quit = 0;
+
+/*
+ * kconsumerd_set_error_socket
+ *
+ * Set the error socket
+ */
+void kconsumerd_set_error_socket(int sock)
+{
+ kconsumerd_error_socket = sock;
+}
+
+/*
+ * kconsumerd_set_command_socket_path
+ *
+ * Set the command socket path
+ */
+void kconsumerd_set_command_socket_path(char *sock)
+{
+ kconsumerd_command_sock_path = sock;
+}
+
+/*
+ * kconsumerd_del_fd
+ *
+ * Remove a fd from the global list protected by a mutex
+ */
+static void kconsumerd_del_fd(struct kconsumerd_fd *lcf)
+{
+ pthread_mutex_lock(&kconsumerd_lock_fds);
+ cds_list_del(&lcf->list);
+ if (kconsumerd_fds_count > 0) {
+ kconsumerd_fds_count--;
+ if (lcf != NULL) {
+ close(lcf->out_fd);
+ close(lcf->consumerd_fd);
+ free(lcf);
+ lcf = NULL;
+ }
+ }
+ pthread_mutex_unlock(&kconsumerd_lock_fds);
+}
+
+/*
+ * kconsumerd_add_fd
+ *
+ * Add a fd to the global list protected by a mutex
+ */
+static int kconsumerd_add_fd(struct lttcomm_kconsumerd_msg *buf, int consumerd_fd)
+{
+ struct kconsumerd_fd *tmp_fd;
+ int ret;
+
+ tmp_fd = malloc(sizeof(struct kconsumerd_fd));
+ tmp_fd->sessiond_fd = buf->fd;
+ tmp_fd->consumerd_fd = consumerd_fd;
+ tmp_fd->state = buf->state;
+ tmp_fd->max_sb_size = buf->max_sb_size;
+ strncpy(tmp_fd->path_name, buf->path_name, PATH_MAX);
+
+ /* Opening the tracefile in write mode */
+ ret = open(tmp_fd->path_name,
+ O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU|S_IRWXG|S_IRWXO);
+ if (ret < 0) {
+ ERR("Opening %s", tmp_fd->path_name);
+ perror("open");
+ goto end;
+ }
+ tmp_fd->out_fd = ret;
+ tmp_fd->out_fd_offset = 0;
+
+ DBG("Adding %s (%d, %d, %d)", tmp_fd->path_name,
+ tmp_fd->sessiond_fd, tmp_fd->consumerd_fd, tmp_fd->out_fd);
+
+ pthread_mutex_lock(&kconsumerd_lock_fds);
+ cds_list_add(&tmp_fd->list, &kconsumerd_fd_list.head);
+ kconsumerd_fds_count++;
+ pthread_mutex_unlock(&kconsumerd_lock_fds);
+
+end:
+ return ret;
+}
+
+/*
+ * kconsumerd_change_fd_state
+ *
+ * Update a fd according to what we just received
+ */
+static void kconsumerd_change_fd_state(int sessiond_fd,
+ enum kconsumerd_fd_state state)
+{
+ struct kconsumerd_fd *iter;
+ cds_list_for_each_entry(iter, &kconsumerd_fd_list.head, list) {
+ if (iter->sessiond_fd == sessiond_fd) {
+ iter->state = state;
+ break;
+ }
+ }
+}
+
+/*
+ * kconsumerd_update_poll_array
+ *
+ * Allocate the pollfd structure and the local view of the out fds
+ * to avoid doing a lookup in the linked list and concurrency issues
+ * when writing is needed.
+ * Returns the number of fds in the structures
+ */
+static int kconsumerd_update_poll_array(struct pollfd **pollfd,
+ struct kconsumerd_fd **local_kconsumerd_fd)
+{
+ struct kconsumerd_fd *iter;
+ int i = 0;
+
+ DBG("Updating poll fd array");
+ pthread_mutex_lock(&kconsumerd_lock_fds);
+
+ cds_list_for_each_entry(iter, &kconsumerd_fd_list.head, list) {
+ DBG("Inside for each");
+ if (iter->state == ACTIVE_FD) {
+ DBG("Active FD %d", iter->consumerd_fd);
+ (*pollfd)[i].fd = iter->consumerd_fd;
+ (*pollfd)[i].events = POLLIN | POLLPRI;
+ local_kconsumerd_fd[i] = iter;
+ i++;
+ }
+ }
+
+ /*
+ * insert the kconsumerd_poll_pipe at the end of the array and don't
+ * increment i so nb_fd is the number of real FD
+ */
+ (*pollfd)[i].fd = kconsumerd_poll_pipe[0];
+ (*pollfd)[i].events = POLLIN;
+
+ kconsumerd_update_fd_array = 0;
+ pthread_mutex_unlock(&kconsumerd_lock_fds);
+ return i;
+}
+
+
+/*
+ * kconsumerd_on_read_subbuffer_mmap
+ *
+ * mmap the ring buffer, read it and write the data to the tracefile.
+ * Returns the number of bytes written
+ */
+static int kconsumerd_on_read_subbuffer_mmap(
+ struct kconsumerd_fd *kconsumerd_fd, unsigned long len)
+{
+ unsigned long mmap_len, mmap_offset, padded_len, padding_len;
+ char *mmap_base;
+ char *padding = NULL;
+ long ret = 0;
+ off_t orig_offset = kconsumerd_fd->out_fd_offset;
+ int fd = kconsumerd_fd->consumerd_fd;
+ int outfd = kconsumerd_fd->out_fd;
+
+ /* get the padded subbuffer size to know the padding required */
+ ret = kernctl_get_padded_subbuf_size(fd, &padded_len);
+ if (ret != 0) {
+ ret = errno;
+ perror("kernctl_get_padded_subbuf_size");
+ goto end;
+ }
+ padding_len = padded_len - len;
+ padding = malloc(padding_len * sizeof(char));
+ memset(padding, '\0', padding_len);
+
+ /* get the len of the mmap region */
+ ret = kernctl_get_mmap_len(fd, &mmap_len);
+ if (ret != 0) {
+ ret = errno;
+ perror("kernctl_get_mmap_len");
+ goto end;
+ }
+
+ /* get the offset inside the fd to mmap */
+ ret = kernctl_get_mmap_read_offset(fd, &mmap_offset);
+ if (ret != 0) {
+ ret = errno;
+ perror("kernctl_get_mmap_read_offset");
+ goto end;
+ }
+
+ mmap_base = mmap(NULL, mmap_len, PROT_READ, MAP_PRIVATE, fd, mmap_offset);
+ if (mmap_base == MAP_FAILED) {
+ perror("Error mmaping");
+ ret = -1;
+ goto end;
+ }
+
+ while (len > 0) {
+ ret = write(outfd, mmap_base, len);
+ if (ret >= len) {
+ len = 0;
+ } else if (ret < 0) {
+ ret = errno;
+ perror("Error in file write");
+ goto end;
+ }
+ /* This won't block, but will start writeout asynchronously */
+ sync_file_range(outfd, kconsumerd_fd->out_fd_offset, ret,
+ SYNC_FILE_RANGE_WRITE);
+ kconsumerd_fd->out_fd_offset += ret;
+ }
+
+ /* once all the data is written, write the padding to disk */
+ ret = write(outfd, padding, padding_len);
+ if (ret < 0) {
+ ret = errno;
+ perror("Error writing padding to file");
+ goto end;
+ }
+
+ /*
+ * This does a blocking write-and-wait on any page that belongs to the
+ * subbuffer prior to the one we just wrote.
+ * Don't care about error values, as these are just hints and ways to
+ * limit the amount of page cache used.
+ */
+ if (orig_offset >= kconsumerd_fd->max_sb_size) {
+ sync_file_range(outfd, orig_offset - kconsumerd_fd->max_sb_size,
+ kconsumerd_fd->max_sb_size,
+ SYNC_FILE_RANGE_WAIT_BEFORE
+ | SYNC_FILE_RANGE_WRITE
+ | SYNC_FILE_RANGE_WAIT_AFTER);
+
+ /*
+ * Give hints to the kernel about how we access the file:
+ * POSIX_FADV_DONTNEED : we won't re-access data in a near future after
+ * we write it.
+ *
+ * We need to call fadvise again after the file grows because the
+ * kernel does not seem to apply fadvise to non-existing parts of the
+ * file.
+ *
+ * Call fadvise _after_ having waited for the page writeback to
+ * complete because the dirty page writeback semantic is not well
+ * defined. So it can be expected to lead to lower throughput in
+ * streaming.
+ */
+ posix_fadvise(outfd, orig_offset - kconsumerd_fd->max_sb_size,
+ kconsumerd_fd->max_sb_size, POSIX_FADV_DONTNEED);
+ }
+ goto end;
+
+end:
+ if (padding != NULL) {
+ free(padding);
+ }
+ return ret;
+}
+
+/*
+ * kconsumerd_on_read_subbuffer
+ *
+ * Splice the data from the ring buffer to the tracefile.
+ * Returns the number of bytes spliced
+ */
+static int kconsumerd_on_read_subbuffer(
+ struct kconsumerd_fd *kconsumerd_fd, unsigned long len)
+{
+ long ret = 0;
+ loff_t offset = 0;
+ off_t orig_offset = kconsumerd_fd->out_fd_offset;
+ int fd = kconsumerd_fd->consumerd_fd;
+ int outfd = kconsumerd_fd->out_fd;
+
+ while (len > 0) {
+ DBG("splice chan to pipe offset %lu (fd : %d)",
+ (unsigned long)offset, fd);
+ ret = splice(fd, &offset, kconsumerd_thread_pipe[1], NULL, len,
+ SPLICE_F_MOVE | SPLICE_F_MORE);
+ DBG("splice chan to pipe ret %ld", ret);
+ if (ret < 0) {
+ ret = errno;
+ perror("Error in relay splice");
+ goto splice_error;
+ }
+
+ ret = splice(kconsumerd_thread_pipe[0], NULL, outfd, NULL, ret,
+ SPLICE_F_MOVE | SPLICE_F_MORE);
+ DBG("splice pipe to file %ld", ret);
+ if (ret < 0) {
+ ret = errno;
+ perror("Error in file splice");
+ goto splice_error;
+ }
+ if (ret >= len) {
+ len = 0;
+ }
+ /* This won't block, but will start writeout asynchronously */
+ sync_file_range(outfd, kconsumerd_fd->out_fd_offset, ret,
+ SYNC_FILE_RANGE_WRITE);
+ kconsumerd_fd->out_fd_offset += ret;
+ }
+
+ /*
+ * This does a blocking write-and-wait on any page that belongs to the
+ * subbuffer prior to the one we just wrote.
+ * Don't care about error values, as these are just hints and ways to
+ * limit the amount of page cache used.
+ */
+ if (orig_offset >= kconsumerd_fd->max_sb_size) {
+ sync_file_range(outfd, orig_offset - kconsumerd_fd->max_sb_size,
+ kconsumerd_fd->max_sb_size,
+ SYNC_FILE_RANGE_WAIT_BEFORE
+ | SYNC_FILE_RANGE_WRITE
+ | SYNC_FILE_RANGE_WAIT_AFTER);
+ /*
+ * Give hints to the kernel about how we access the file:
+ * POSIX_FADV_DONTNEED : we won't re-access data in a near future after
+ * we write it.
+ *
+ * We need to call fadvise again after the file grows because the
+ * kernel does not seem to apply fadvise to non-existing parts of the
+ * file.
+ *
+ * Call fadvise _after_ having waited for the page writeback to
+ * complete because the dirty page writeback semantic is not well
+ * defined. So it can be expected to lead to lower throughput in
+ * streaming.
+ */
+ posix_fadvise(outfd, orig_offset - kconsumerd_fd->max_sb_size,
+ kconsumerd_fd->max_sb_size, POSIX_FADV_DONTNEED);
+ }
+ goto end;
+
+splice_error:
+ /* send the appropriate error description to sessiond */
+ switch(ret) {
+ case EBADF:
+ kconsumerd_send_error(KCONSUMERD_SPLICE_EBADF);
+ break;
+ case EINVAL:
+ kconsumerd_send_error(KCONSUMERD_SPLICE_EINVAL);
+ break;
+ case ENOMEM:
+ kconsumerd_send_error(KCONSUMERD_SPLICE_ENOMEM);
+ break;
+ case ESPIPE:
+ kconsumerd_send_error(KCONSUMERD_SPLICE_ESPIPE);
+ break;
+ }
+
+end:
+ return ret;
+}
+
+/*
+ * kconsumerd_read_subbuffer
+ *
+ * Consume data on a file descriptor and write it on a trace file
+ */
+static int kconsumerd_read_subbuffer(struct kconsumerd_fd *kconsumerd_fd)
+{
+ unsigned long len;
+ int err;
+ long ret = 0;
+ int infd = kconsumerd_fd->consumerd_fd;
+
+ DBG("In kconsumerd_read_subbuffer (infd : %d)", infd);
+ /* Get the next subbuffer */
+ err = kernctl_get_next_subbuf(infd);
+ if (err != 0) {
+ ret = errno;
+ perror("Reserving sub buffer failed (everything is normal, "
+ "it is due to concurrency)");
+ goto end;
+ }
+
+ switch (DEFAULT_KERNEL_CHANNEL_OUTPUT) {
+ case LTTNG_KERNEL_SPLICE:
+ /* read the whole subbuffer */
+ err = kernctl_get_padded_subbuf_size(infd, &len);
+ if (err != 0) {
+ ret = errno;
+ perror("Getting sub-buffer len failed.");
+ goto end;
+ }
+
+ /* splice the subbuffer to the tracefile */
+ ret = kconsumerd_on_read_subbuffer(kconsumerd_fd, len);
+ if (ret < 0) {
+ /*
+ * display the error but continue processing to try
+ * to release the subbuffer
+ */
+ ERR("Error splicing to tracefile");
+ }
+ break;
+ case LTTNG_KERNEL_MMAP:
+ /* read the used subbuffer size */
+ err = kernctl_get_subbuf_size(infd, &len);
+ if (err != 0) {
+ ret = errno;
+ perror("Getting sub-buffer len failed.");
+ goto end;
+ }
+ /* write the subbuffer to the tracefile */
+ ret = kconsumerd_on_read_subbuffer_mmap(kconsumerd_fd, len);
+ if (ret < 0) {
+ /*
+ * display the error but continue processing to try
+ * to release the subbuffer
+ */
+ ERR("Error writing to tracefile");
+ }
+ break;
+ default:
+ ERR("Unknown output method");
+ ret = -1;
+ }
+
+ err = kernctl_put_next_subbuf(infd);
+ if (err != 0) {
+ ret = errno;
+ if (errno == EFAULT) {
+ perror("Error in unreserving sub buffer\n");
+ } else if (errno == EIO) {
+ /* Should never happen with newer LTTng versions */
+ perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
+ }
+ goto end;
+ }
+
+end:
+ return ret;
+}
+
+/*
+ * kconsumerd_consumerd_recv_fd
+ *
+ * Receives an array of file descriptors and the associated
+ * structures describing each fd (path name).
+ * Returns the size of received data
+ */
+static int kconsumerd_consumerd_recv_fd(int sfd, int size,
+ enum kconsumerd_command cmd_type)
+{
+ struct msghdr msg;
+ struct iovec iov[1];
+ int ret = 0, i, tmp2;
+ struct cmsghdr *cmsg;
+ int nb_fd;
+ char recv_fd[CMSG_SPACE(sizeof(int))];
+ struct lttcomm_kconsumerd_msg lkm;
+
+ /* the number of fds we are about to receive */
+ nb_fd = size / sizeof(struct lttcomm_kconsumerd_msg);
+
+ for (i = 0; i < nb_fd; i++) {
+ memset(&msg, 0, sizeof(msg));
+
+ /* Prepare to receive the structures */
+ iov[0].iov_base = &lkm;
+ iov[0].iov_len = sizeof(lkm);
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 1;
+
+ msg.msg_control = recv_fd;
+ msg.msg_controllen = sizeof(recv_fd);
+
+ DBG("Waiting to receive fd");
+ if ((ret = recvmsg(sfd, &msg, 0)) < 0) {
+ perror("recvmsg");
+ continue;
+ }
+
+ if (ret != (size / nb_fd)) {
+ ERR("Received only %d, expected %d", ret, size);
+ kconsumerd_send_error(KCONSUMERD_ERROR_RECV_FD);
+ goto end;
+ }
+
+ cmsg = CMSG_FIRSTHDR(&msg);
+ if (!cmsg) {
+ ERR("Invalid control message header");
+ ret = -1;
+ kconsumerd_send_error(KCONSUMERD_ERROR_RECV_FD);
+ goto end;
+ }
+ /* if we received fds */
+ if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
+ switch (cmd_type) {
+ case ADD_STREAM:
+ DBG("kconsumerd_add_fd %s (%d)", lkm.path_name, (CMSG_DATA(cmsg)[0]));
+ ret = kconsumerd_add_fd(&lkm, (CMSG_DATA(cmsg)[0]));
+ if (ret < 0) {
+ kconsumerd_send_error(KCONSUMERD_OUTFD_ERROR);
+ goto end;
+ }
+ break;
+ case UPDATE_STREAM:
+ kconsumerd_change_fd_state(lkm.fd, lkm.state);
+ break;
+ default:
+ break;
+ }
+ /* flag to tell the polling thread to update its fd array */
+ kconsumerd_update_fd_array = 1;
+ /* signal the poll thread */
+ tmp2 = write(kconsumerd_poll_pipe[1], "4", 1);
+ } else {
+ ERR("Didn't received any fd");
+ kconsumerd_send_error(KCONSUMERD_ERROR_RECV_FD);
+ ret = -1;
+ goto end;
+ }
+ }
+
+end:
+ DBG("kconsumerd_consumerd_recv_fd thread exiting");
+ return ret;
+}
+
+/*
+ * kconsumerd_thread_poll_fds
+ *
+ * This thread polls the fds in the ltt_fd_list to consume the data
+ * and write it to tracefile if necessary.
+ */
+void *kconsumerd_thread_poll_fds(void *data)
+{
+ int num_rdy, num_hup, high_prio, ret, i;
+ struct pollfd *pollfd = NULL;
+ /* local view of the fds */
+ struct kconsumerd_fd **local_kconsumerd_fd = NULL;
+ /* local view of kconsumerd_fds_count */
+ int nb_fd = 0;
+ char tmp;
+ int tmp2;
+
+ ret = pipe(kconsumerd_thread_pipe);
+ if (ret < 0) {
+ perror("Error creating pipe");
+ goto end;
+ }
+
+ local_kconsumerd_fd = malloc(sizeof(struct kconsumerd_fd));
+
+ while (1) {
+ high_prio = 0;
+ num_hup = 0;
+
+ /*
+ * the ltt_fd_list has been updated, we need to update our
+ * local array as well
+ */
+ if (kconsumerd_update_fd_array == 1) {
+ if (pollfd != NULL) {
+ free(pollfd);
+ pollfd = NULL;
+ }
+ if (local_kconsumerd_fd != NULL) {
+ free(local_kconsumerd_fd);
+ local_kconsumerd_fd = NULL;
+ }
+ /* allocate for all fds + 1 for the kconsumerd_poll_pipe */
+ pollfd = malloc((kconsumerd_fds_count + 1) * sizeof(struct pollfd));
+ if (pollfd == NULL) {
+ perror("pollfd malloc");
+ goto end;
+ }
+ /* allocate for all fds + 1 for the kconsumerd_poll_pipe */
+ local_kconsumerd_fd = malloc((kconsumerd_fds_count + 1) *
+ sizeof(struct kconsumerd_fd));
+ if (local_kconsumerd_fd == NULL) {
+ perror("local_kconsumerd_fd malloc");
+ goto end;
+ }
+ ret = kconsumerd_update_poll_array(&pollfd, local_kconsumerd_fd);
+ if (ret < 0) {
+ ERR("Error in allocating pollfd or local_outfds");
+ kconsumerd_send_error(KCONSUMERD_POLL_ERROR);
+ goto end;
+ }
+ nb_fd = ret;
+ }
+
+ /* poll on the array of fds */
+ DBG("polling on %d fd", nb_fd + 1);
+ num_rdy = poll(pollfd, nb_fd + 1, kconsumerd_poll_timeout);
+ DBG("poll num_rdy : %d", num_rdy);
+ if (num_rdy == -1) {
+ perror("Poll error");
+ kconsumerd_send_error(KCONSUMERD_POLL_ERROR);
+ goto end;
+ } else if (num_rdy == 0) {
+ DBG("Polling thread timed out");
+ goto end;
+ }
+
+ /* No FDs and kconsumerd_quit, kconsumerd_cleanup the thread */
+ if (nb_fd == 0 && kconsumerd_quit == 1) {
+ goto end;
+ }
+
+ /*
+ * if only the kconsumerd_poll_pipe triggered poll to return just
+ * return to the beginning of the loop to update the array
+ */
+ if (num_rdy == 1 && pollfd[nb_fd].revents == POLLIN) {
+ DBG("kconsumerd_poll_pipe wake up");
+ tmp2 = read(kconsumerd_poll_pipe[0], &tmp, 1);
+ continue;
+ }
+
+ /* Take care of high priority channels first. */
+ for (i = 0; i < nb_fd; i++) {
+ switch(pollfd[i].revents) {
+ case POLLERR:
+ ERR("Error returned in polling fd %d.", pollfd[i].fd);
+ kconsumerd_del_fd(local_kconsumerd_fd[i]);
+ kconsumerd_update_fd_array = 1;
+ num_hup++;
+ break;
+ case POLLHUP:
+ DBG("Polling fd %d tells it has hung up.", pollfd[i].fd);
+ kconsumerd_del_fd(local_kconsumerd_fd[i]);
+ kconsumerd_update_fd_array = 1;
+ num_hup++;
+ break;
+ case POLLNVAL:
+ ERR("Polling fd %d tells fd is not open.", pollfd[i].fd);
+ kconsumerd_del_fd(local_kconsumerd_fd[i]);
+ kconsumerd_update_fd_array = 1;
+ num_hup++;
+ break;
+ case POLLPRI:
+ DBG("Urgent read on fd %d", pollfd[i].fd);
+ high_prio = 1;
+ ret = kconsumerd_read_subbuffer(local_kconsumerd_fd[i]);
+ /* it's ok to have an unavailable sub-buffer */
+ if (ret == EAGAIN) {
+ ret = 0;
+ }
+ break;
+ }
+ }
+
+ /* If every buffer FD has hung up, we end the read loop here */
+ if (nb_fd > 0 && num_hup == nb_fd) {
+ DBG("every buffer FD has hung up\n");
+ if (kconsumerd_quit == 1) {
+ goto end;
+ }
+ continue;
+ }
+
+ /* Take care of low priority channels. */
+ if (high_prio == 0) {
+ for (i = 0; i < nb_fd; i++) {
+ if (pollfd[i].revents == POLLIN) {
+ DBG("Normal read on fd %d", pollfd[i].fd);
+ ret = kconsumerd_read_subbuffer(local_kconsumerd_fd[i]);
+ /* it's ok to have an unavailable subbuffer */
+ if (ret == EAGAIN) {
+ ret = 0;
+ }
+ }
+ }
+ }
+ }
+end:
+ DBG("polling thread exiting");
+ if (pollfd != NULL) {
+ free(pollfd);
+ pollfd = NULL;
+ }
+ if (local_kconsumerd_fd != NULL) {
+ free(local_kconsumerd_fd);
+ local_kconsumerd_fd = NULL;
+ }
+ kconsumerd_cleanup();
+ return NULL;
+}
+
+/*
+ * kconsumerd_create_poll_pipe
+ *
+ * create the pipe to wake to polling thread when needed
+ */
+int kconsumerd_create_poll_pipe()
+{
+ return pipe(kconsumerd_poll_pipe);
+}
+
+/*
+ * kconsumerd_thread_receive_fds
+ *
+ * This thread listens on the consumerd socket and
+ * receives the file descriptors from ltt-sessiond
+ */
+void *kconsumerd_thread_receive_fds(void *data)
+{
+ int sock, client_socket, ret;
+ struct lttcomm_kconsumerd_header tmp;
+
+ DBG("Creating command socket %s", kconsumerd_command_sock_path);
+ unlink(kconsumerd_command_sock_path);
+ client_socket = lttcomm_create_unix_sock(kconsumerd_command_sock_path);
+ if (client_socket < 0) {
+ ERR("Cannot create command socket");
+ goto end;
+ }
+
+ ret = lttcomm_listen_unix_sock(client_socket);
+ if (ret < 0) {
+ goto end;
+ }
+
+ DBG("Sending ready command to ltt-sessiond");
+ ret = kconsumerd_send_error(KCONSUMERD_COMMAND_SOCK_READY);
+ if (ret < 0) {
+ ERR("Error sending ready command to ltt-sessiond");
+ goto end;
+ }
+
+ /* Blocking call, waiting for transmission */
+ sock = lttcomm_accept_unix_sock(client_socket);
+ if (sock <= 0) {
+ WARN("On accept");
+ goto end;
+ }
+ while (1) {
+ /* We first get the number of fd we are about to receive */
+ ret = lttcomm_recv_unix_sock(sock, &tmp,
+ sizeof(struct lttcomm_kconsumerd_header));
+ if (ret <= 0) {
+ ERR("Communication interrupted on command socket");
+ goto end;
+ }
+ if (tmp.cmd_type == STOP) {
+ DBG("Received STOP command");
+ goto end;
+ }
+ /* we received a command to add or update fds */
+ ret = kconsumerd_consumerd_recv_fd(sock, tmp.payload_size, tmp.cmd_type);
+ if (ret <= 0) {
+ ERR("Receiving the FD, exiting");
+ goto end;
+ }
+ }
+
+end:
+ DBG("kconsumerd_thread_receive_fds exiting");
+
+ /*
+ * when all fds have hung up, the polling thread
+ * can exit cleanly
+ */
+ kconsumerd_quit = 1;
+
+ /*
+ * 2s of grace period, if no polling events occur during
+ * this period, the polling thread will exit even if there
+ * are still open FDs (should not happen, but safety mechanism).
+ */
+ kconsumerd_poll_timeout = KCONSUMERD_POLL_GRACE_PERIOD;
+
+ /* wake up the polling thread */
+ ret = write(kconsumerd_poll_pipe[1], "4", 1);
+ if (ret < 0) {
+ perror("poll pipe write");
+ }
+ return NULL;
+}
+
+/*
+ * kconsumerd_cleanup
+ *
+ * Cleanup the daemon's socket on exit
+ */
+void kconsumerd_cleanup()
+{
+ struct kconsumerd_fd *iter;
+
+ /* remove the socket file */
+ unlink(kconsumerd_command_sock_path);
+
+ /* close all outfd */
+ cds_list_for_each_entry(iter, &kconsumerd_fd_list.head, list) {
+ kconsumerd_del_fd(iter);
+ }
+}
+
+/*
+ * kconsumerd_send_error
+ *
+ * send return code to ltt-sessiond
+ */
+int kconsumerd_send_error(enum lttcomm_return_code cmd)
+{
+ if (kconsumerd_error_socket > 0) {
+ return lttcomm_send_unix_sock(kconsumerd_error_socket, &cmd,
+ sizeof(enum lttcomm_sessiond_command));
+ }
+
+ return 0;
+}
projects / lttng-tools.git / commitdiff
