-/*
- * 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; only version 2
- * of the License.
- *
- * 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 <assert.h>
-
-#include "libkernelctl.h"
-#include "liblttkconsumerd.h"
-#include "lttngerr.h"
-
-static
-struct kconsumerd_global_data {
- /*
- * kconsumerd_data.lock protects kconsumerd_data.fd_list,
- * kconsumerd_data.fds_count, and kconsumerd_data.need_update. It
- * ensures the count matches the number of items in the fd_list.
- * It ensures the list updates *always* trigger an fd_array
- * update (therefore need to make list update vs
- * kconsumerd_data.need_update flag update atomic, and also flag
- * read, fd array and flag clear atomic).
- */
- pthread_mutex_t lock;
- /*
- * Number of element for the list below. Protected by
- * kconsumerd_data.lock.
- */
- unsigned int fds_count;
- /*
- * List of FDs. Protected by kconsumerd_data.lock.
- */
- struct kconsumerd_fd_list fd_list;
- /*
- * Flag specifying if the local array of FDs needs update in the
- * poll function. Protected by kconsumerd_data.lock.
- */
- unsigned int need_update;
-} kconsumerd_data = {
- .fd_list.head = CDS_LIST_HEAD_INIT(kconsumerd_data.fd_list.head),
-};
-
-/* communication with splice */
-static int kconsumerd_thread_pipe[2];
-
-/* pipe to wake the poll thread when necessary */
-static int kconsumerd_poll_pipe[2];
-
-/* to let the signal handler wake up the fd receiver thread */
-static int kconsumerd_should_quit[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 quit when all fd hung up.
- * Updated by the kconsumerd_thread_receive_fds when it notices that all
- * fds has hung up. Also updated by the signal handler
- * (kconsumerd_should_exit()). Read by the polling threads.
- */
-static volatile 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_find_session_fd
- *
- * Find a session fd in the global list.
- * The kconsumerd_data.lock must be locked during this call
- *
- * Return 1 if found else 0
- */
-static int kconsumerd_find_session_fd(int fd)
-{
- struct kconsumerd_fd *iter;
-
- cds_list_for_each_entry(iter, &kconsumerd_data.fd_list.head, list) {
- if (iter->sessiond_fd == fd) {
- DBG("Duplicate session fd %d", fd);
- return 1;
- }
- }
-
- return 0;
-}
-
-/*
- * 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_data.lock);
- cds_list_del(&lcf->list);
- if (kconsumerd_data.fds_count > 0) {
- kconsumerd_data.fds_count--;
- if (lcf != NULL) {
- close(lcf->out_fd);
- close(lcf->consumerd_fd);
- free(lcf);
- lcf = NULL;
- }
- }
- kconsumerd_data.need_update = 1;
- pthread_mutex_unlock(&kconsumerd_data.lock);
-}
-
-/*
- * 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)
-{
- int ret;
- struct kconsumerd_fd *tmp_fd;
-
- pthread_mutex_lock(&kconsumerd_data.lock);
- /* Check if already exist */
- ret = kconsumerd_find_session_fd(buf->fd);
- if (ret == 1) {
- goto end;
- }
-
- 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);
- tmp_fd->path_name[PATH_MAX - 1] = '\0';
-
- /* 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);
-
- cds_list_add(&tmp_fd->list, &kconsumerd_data.fd_list.head);
- kconsumerd_data.fds_count++;
- kconsumerd_data.need_update = 1;
-end:
- pthread_mutex_unlock(&kconsumerd_data.lock);
- 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;
-
- pthread_mutex_lock(&kconsumerd_data.lock);
- cds_list_for_each_entry(iter, &kconsumerd_data.fd_list.head, list) {
- if (iter->sessiond_fd == sessiond_fd) {
- iter->state = state;
- break;
- }
- }
- kconsumerd_data.need_update = 1;
- pthread_mutex_unlock(&kconsumerd_data.lock);
-}
-
-/*
- * 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
- * Called with kconsumerd_data.lock held.
- */
-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");
-
- cds_list_for_each_entry(iter, &kconsumerd_data.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;
- 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_EVENT_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_EVENT_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_poll_socket
- *
- * Poll on the should_quit pipe and the command socket
- * return -1 on error and should exit, 0 if data is
- * available on the command socket
- */
-int kconsumerd_poll_socket(struct pollfd *kconsumerd_sockpoll)
-{
- int num_rdy;
-
- num_rdy = poll(kconsumerd_sockpoll, 2, -1);
- if (num_rdy == -1) {
- perror("Poll error");
- goto exit;
- }
- if (kconsumerd_sockpoll[0].revents == POLLIN) {
- DBG("kconsumerd_should_quit wake up");
- goto exit;
- }
- return 0;
-
-exit:
- return -1;
-}
-
-/*
- * 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,
- struct pollfd *kconsumerd_sockpoll, int size,
- enum kconsumerd_command cmd_type)
-{
- 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);
-
- /*
- * nb_fd is the number of fds we receive. One fd per recvmsg.
- */
- for (i = 0; i < nb_fd; i++) {
- struct msghdr msg = { 0 };
-
- /* 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 (kconsumerd_poll_socket(kconsumerd_sockpoll) < 0) {
- goto end;
- }
-
- 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, ((int *) CMSG_DATA(cmsg))[0]);
- ret = kconsumerd_add_fd(&lkm, ((int *) 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;
- }
- /* signal the poll thread */
- tmp2 = write(kconsumerd_poll_pipe[1], "4", 1);
- if (tmp2 < 0) {
- perror("write kconsumerd poll");
- }
- } else {
- ERR("Didn't received any fd");
- kconsumerd_send_error(KCONSUMERD_ERROR_RECV_FD);
- ret = -1;
- goto end;
- }
- }
-
-end:
- 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_data.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
- */
- pthread_mutex_lock(&kconsumerd_data.lock);
- if (kconsumerd_data.need_update) {
- 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_data.fds_count + 1) * sizeof(struct pollfd));
- if (pollfd == NULL) {
- perror("pollfd malloc");
- pthread_mutex_unlock(&kconsumerd_data.lock);
- goto end;
- }
-
- /* allocate for all fds + 1 for the kconsumerd_poll_pipe */
- local_kconsumerd_fd = malloc((kconsumerd_data.fds_count + 1) *
- sizeof(struct kconsumerd_fd));
- if (local_kconsumerd_fd == NULL) {
- perror("local_kconsumerd_fd malloc");
- pthread_mutex_unlock(&kconsumerd_data.lock);
- 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);
- pthread_mutex_unlock(&kconsumerd_data.lock);
- goto end;
- }
- nb_fd = ret;
- kconsumerd_data.need_update = 0;
- }
- pthread_mutex_unlock(&kconsumerd_data.lock);
-
- /* 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 the kconsumerd_poll_pipe triggered poll go
- * directly to the beginning of the loop to update the
- * array. We want to prioritize array update over
- * low-priority reads.
- */
- if (pollfd[nb_fd].revents == POLLIN) {
- DBG("kconsumerd_poll_pipe wake up");
- tmp2 = read(kconsumerd_poll_pipe[0], &tmp, 1);
- if (tmp2 < 0) {
- perror("read kconsumerd poll");
- }
- 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]);
- num_hup++;
- break;
- case POLLHUP:
- DBG("Polling fd %d tells it has hung up.", pollfd[i].fd);
- kconsumerd_del_fd(local_kconsumerd_fd[i]);
- num_hup++;
- break;
- case POLLNVAL:
- ERR("Polling fd %d tells fd is not open.", pollfd[i].fd);
- kconsumerd_del_fd(local_kconsumerd_fd[i]);
- 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;
- }
- return NULL;
-}
-
-/*
- * kconsumerd_init(void)
- *
- * initialise the necessary environnement :
- * - inform the polling thread to update the polling array
- * - create the poll_pipe
- * - create the should_quit pipe (for signal handler)
- */
-int kconsumerd_init(void)
-{
- int ret;
-
- /* need to update the polling array at init time */
- kconsumerd_data.need_update = 1;
-
- ret = pipe(kconsumerd_poll_pipe);
- if (ret < 0) {
- perror("Error creating poll pipe");
- goto end;
- }
-
- ret = pipe(kconsumerd_should_quit);
- if (ret < 0) {
- perror("Error creating recv pipe");
- goto end;
- }
-
-end:
- return ret;
-}
-
-/*
- * 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;
- /*
- * structure to poll for incoming data on communication socket
- * avoids making blocking sockets
- */
- struct pollfd kconsumerd_sockpoll[2];
-
-
- 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;
- }
-
- ret = fcntl(client_socket, F_SETFL, O_NONBLOCK);
- if (ret < 0) {
- perror("fcntl O_NONBLOCK");
- goto end;
- }
-
- /* prepare the FDs to poll : to client socket and the should_quit pipe */
- kconsumerd_sockpoll[0].fd = kconsumerd_should_quit[0];
- kconsumerd_sockpoll[0].events = POLLIN | POLLPRI;
- kconsumerd_sockpoll[1].fd = client_socket;
- kconsumerd_sockpoll[1].events = POLLIN | POLLPRI;
-
- if (kconsumerd_poll_socket(kconsumerd_sockpoll) < 0) {
- goto end;
- }
- DBG("Connection on client_socket");
-
- /* Blocking call, waiting for transmission */
- sock = lttcomm_accept_unix_sock(client_socket);
- if (sock <= 0) {
- WARN("On accept");
- goto end;
- }
- ret = fcntl(sock, F_SETFL, O_NONBLOCK);
- if (ret < 0) {
- perror("fcntl O_NONBLOCK");
- goto end;
- }
-
- /* update the polling structure to poll on the established socket */
- kconsumerd_sockpoll[1].fd = sock;
- kconsumerd_sockpoll[1].events = POLLIN | POLLPRI;
-
- while (1) {
- if (kconsumerd_poll_socket(kconsumerd_sockpoll) < 0) {
- goto end;
- }
- DBG("Incoming fds on sock");
-
- /* 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;
- }
- if (kconsumerd_quit) {
- DBG("kconsumerd_thread_receive_fds received quit from signal");
- goto end;
- }
-
- /* we received a command to add or update fds */
- ret = kconsumerd_consumerd_recv_fd(sock, kconsumerd_sockpoll,
- tmp.payload_size, tmp.cmd_type);
- if (ret <= 0) {
- ERR("Receiving the FD, exiting");
- goto end;
- }
- DBG("received fds on sock");
- }
-
-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(void)
-{
- struct kconsumerd_fd *iter, *tmp;
-
- /* remove the socket file */
- unlink(kconsumerd_command_sock_path);
-
- /*
- * close all outfd. Called when there are no more threads
- * running (after joining on the threads), no need to protect
- * list iteration with mutex.
- */
- cds_list_for_each_entry_safe(iter, tmp, &kconsumerd_data.fd_list.head, list) {
- kconsumerd_del_fd(iter);
- }
-}
-
-/*
- * kconsumerd_should_exit
- *
- * Called from signal handler.
- */
-void kconsumerd_should_exit(void)
-{
- int ret;
- kconsumerd_quit = 1;
- ret = write(kconsumerd_should_quit[1], "4", 1);
- if (ret < 0) {
- perror("write kconsumerd quit");
- }
-}
-
-/*
- * 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 / blobdiff