--- /dev/null
+#ifndef _LTTNG_SESSIOND_COMM_H
+#define _LTTNG_SESSIOND_COMM_H
+
+/*
+ * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
+ * 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.
+ */
+
+/*
+ * This header is meant for liblttng and libust internal use ONLY.
+ * These declarations should NOT be considered stable API.
+ */
+
+#include <limits.h>
+#include <lttng/lttng.h>
+
+#define LTTNG_RUNDIR "/var/run/lttng"
+
+/* Default unix socket path */
+#define DEFAULT_GLOBAL_CLIENT_UNIX_SOCK LTTNG_RUNDIR "/client-ltt-sessiond"
+#define DEFAULT_GLOBAL_APPS_UNIX_SOCK LTTNG_RUNDIR "/apps-ltt-sessiond"
+#define DEFAULT_HOME_APPS_UNIX_SOCK "%s/.apps-ltt-sessiond"
+#define DEFAULT_HOME_CLIENT_UNIX_SOCK "%s/.client-ltt-sessiond"
+
+/* Queue size of listen(2) */
+#define MAX_LISTEN 10
+
+/* Get the error code index from 0 since
+ * LTTCOMM_OK start at 1000
+ */
+#define LTTCOMM_ERR_INDEX(code) (code - LTTCOMM_OK)
+
+enum lttcomm_sessiond_command {
+ /* Tracer command */
+ LTTNG_ADD_CONTEXT,
+ LTTNG_CALIBRATE,
+ LTTNG_DISABLE_CHANNEL,
+ LTTNG_DISABLE_EVENT,
+ LTTNG_DISABLE_ALL_EVENT,
+ LTTNG_ENABLE_CHANNEL,
+ LTTNG_ENABLE_EVENT,
+ LTTNG_ENABLE_ALL_EVENT,
+ /* Session daemon command */
+ LTTNG_CREATE_SESSION,
+ LTTNG_DESTROY_SESSION,
+ LTTNG_LIST_CHANNELS,
+ LTTNG_LIST_DOMAINS,
+ LTTNG_LIST_EVENTS,
+ LTTNG_LIST_SESSIONS,
+ LTTNG_LIST_TRACEPOINTS,
+ LTTNG_START_TRACE,
+ LTTNG_STOP_TRACE,
+};
+
+/*
+ * lttcomm error code.
+ */
+enum lttcomm_return_code {
+ LTTCOMM_OK = 1000, /* Ok */
+ LTTCOMM_ERR, /* Unknown Error */
+ LTTCOMM_UND, /* Undefine command */
+ LTTCOMM_NOT_IMPLEMENTED, /* Command not implemented */
+ LTTCOMM_UNKNOWN_DOMAIN, /* Tracing domain not known */
+ LTTCOMM_ALLOC_FAIL, /* Trace allocation fail */
+ LTTCOMM_NO_SESSION, /* No session found */
+ LTTCOMM_CREATE_FAIL, /* Create trace fail */
+ LTTCOMM_SESSION_FAIL, /* Create session fail */
+ LTTCOMM_START_FAIL, /* Start tracing fail */
+ LTTCOMM_STOP_FAIL, /* Stop tracing fail */
+ LTTCOMM_LIST_FAIL, /* Listing apps fail */
+ LTTCOMM_NO_APPS, /* No traceable application */
+ LTTCOMM_SESS_NOT_FOUND, /* Session name not found */
+ LTTCOMM_NO_TRACE, /* No trace exist */
+ LTTCOMM_FATAL, /* Session daemon had a fatal error */
+ LTTCOMM_NO_TRACEABLE, /* Error for non traceable app */
+ LTTCOMM_SELECT_SESS, /* Must select a session */
+ LTTCOMM_EXIST_SESS, /* Session name already exist */
+ LTTCOMM_NO_EVENT, /* No event found */
+ LTTCOMM_KERN_NA, /* Kernel tracer unavalable */
+ LTTCOMM_KERN_EVENT_EXIST, /* Kernel event already exists */
+ LTTCOMM_KERN_SESS_FAIL, /* Kernel create session failed */
+ LTTCOMM_KERN_CHAN_FAIL, /* Kernel create channel failed */
+ LTTCOMM_KERN_CHAN_NOT_FOUND, /* Kernel channel not found */
+ LTTCOMM_KERN_CHAN_DISABLE_FAIL, /* Kernel disable channel failed */
+ LTTCOMM_KERN_CHAN_ENABLE_FAIL, /* Kernel enable channel failed */
+ LTTCOMM_KERN_CONTEXT_FAIL, /* Kernel add context failed */
+ LTTCOMM_KERN_ENABLE_FAIL, /* Kernel enable event failed */
+ LTTCOMM_KERN_DISABLE_FAIL, /* Kernel disable event failed */
+ LTTCOMM_KERN_META_FAIL, /* Kernel open metadata failed */
+ LTTCOMM_KERN_START_FAIL, /* Kernel start trace failed */
+ LTTCOMM_KERN_STOP_FAIL, /* Kernel stop trace failed */
+ LTTCOMM_KERN_CONSUMER_FAIL, /* Kernel consumer start failed */
+ LTTCOMM_KERN_STREAM_FAIL, /* Kernel create stream failed */
+ LTTCOMM_KERN_DIR_FAIL, /* Kernel trace directory creation failed */
+ LTTCOMM_KERN_DIR_EXIST, /* Kernel trace directory exist */
+ LTTCOMM_KERN_NO_SESSION, /* No kernel session found */
+ LTTCOMM_KERN_LIST_FAIL, /* Kernel listing events failed */
+ KCONSUMERD_COMMAND_SOCK_READY, /* when kconsumerd command socket ready */
+ KCONSUMERD_SUCCESS_RECV_FD, /* success on receiving fds */
+ KCONSUMERD_ERROR_RECV_FD, /* error on receiving fds */
+ KCONSUMERD_POLL_ERROR, /* Error in polling thread in kconsumerd */
+ KCONSUMERD_POLL_NVAL, /* Poll on closed fd */
+ KCONSUMERD_POLL_HUP, /* All fds have hungup */
+ KCONSUMERD_EXIT_SUCCESS, /* kconsumerd exiting normally */
+ KCONSUMERD_EXIT_FAILURE, /* kconsumerd exiting on error */
+ KCONSUMERD_OUTFD_ERROR, /* error opening the tracefile */
+ KCONSUMERD_SPLICE_EBADF, /* EBADF from splice(2) */
+ KCONSUMERD_SPLICE_EINVAL, /* EINVAL from splice(2) */
+ KCONSUMERD_SPLICE_ENOMEM, /* ENOMEM from splice(2) */
+ KCONSUMERD_SPLICE_ESPIPE, /* ESPIPE from splice(2) */
+ /* MUST be last element */
+ LTTCOMM_NR, /* Last element */
+};
+
+/*
+ * Data structure received from lttng client to session daemon.
+ */
+struct lttcomm_session_msg {
+ uint32_t cmd_type; /* enum lttcomm_sessiond_command */
+ struct lttng_session session;
+ struct lttng_domain domain;
+ union {
+ struct {
+ char channel_name[NAME_MAX];
+ char name[NAME_MAX];
+ } disable;
+ /* Event data */
+ struct {
+ char channel_name[NAME_MAX];
+ struct lttng_event event;
+ } enable;
+ /* Create channel */
+ struct {
+ struct lttng_channel chan;
+ } channel;
+ /* Context */
+ struct {
+ char channel_name[NAME_MAX];
+ char event_name[NAME_MAX];
+ struct lttng_event_context ctx;
+ } context;
+ /* List */
+ struct {
+ char channel_name[NAME_MAX];
+ } list;
+ struct lttng_calibrate calibrate;
+ } u;
+};
+
+/*
+ * Data structure for the response from sessiond to the lttng client.
+ */
+struct lttcomm_lttng_msg {
+ uint32_t cmd_type; /* enum lttcomm_sessiond_command */
+ uint32_t ret_code; /* enum lttcomm_return_code */
+ uint32_t pid; /* pid_t */
+ uint32_t data_size;
+ /* Contains: trace_name + data */
+ char payload[];
+};
+
+/*
+ * Data structures for the kconsumerd communications
+ *
+ * The header structure is sent to the kconsumerd daemon to inform
+ * how many lttcomm_kconsumerd_msg it is about to receive
+ */
+struct lttcomm_kconsumerd_header {
+ uint32_t payload_size;
+ uint32_t cmd_type; /* enum kconsumerd_command */
+};
+
+/* lttcomm_kconsumerd_msg represents a file descriptor to consume the
+ * data and a path name to write it
+ */
+struct lttcomm_kconsumerd_msg {
+ char path_name[PATH_MAX];
+ int fd;
+ uint32_t state; /* enum lttcomm_kconsumerd_fd_state */
+ unsigned long max_sb_size; /* the subbuffer size for this channel */
+};
+
+extern int lttcomm_create_unix_sock(const char *pathname);
+extern int lttcomm_connect_unix_sock(const char *pathname);
+extern int lttcomm_accept_unix_sock(int sock);
+extern int lttcomm_listen_unix_sock(int sock);
+extern int lttcomm_close_unix_sock(int sock);
+/* Send fd(s) over a unix socket. */
+extern ssize_t lttcomm_send_fds_unix_sock(int sock, void *buf, int *fds,
+ size_t nb_fd, size_t len);
+extern ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len);
+extern ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len);
+extern const char *lttcomm_get_readable_code(enum lttcomm_return_code code);
+
+#endif /* _LTTNG_SESSIOND_COMM_H */
--- /dev/null
+/*
+ * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
+ *
+ * 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 <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <assert.h>
+
+#include <lttng-sessiond-comm.h>
+
+/*
+ * Human readable error message.
+ */
+static const char *lttcomm_readable_code[] = {
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_FAIL) ] = "Create trace failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_COMMAND_SOCK_READY) ] = "Kconsumerd command socket ready",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_SUCCESS_RECV_FD) ] = "Kconsumerd success on receiving fds",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_ERROR_RECV_FD) ] = "Kconsumerd error on receiving fds",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_ERROR) ] = "Kconsumerd error in polling thread",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_NVAL) ] = "Kconsumerd polling on closed fd",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_HUP) ] = "Kconsumerd all fd hung up",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_SUCCESS) ] = "Kconsumerd exiting normally",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_FAILURE) ] = "Kconsumerd exiting on error",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_OUTFD_ERROR) ] = "Kconsumerd error opening the tracefile",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EBADF) ] = "Kconsumerd splice EBADF",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EINVAL) ] = "Kconsumerd splice EINVAL",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ENOMEM) ] = "Kconsumerd splice ENOMEM",
+ [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ESPIPE) ] = "Kconsumerd splice ESPIPE",
+ [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
+};
+
+/*
+ * lttcom_get_readable_code
+ *
+ * Return ptr to string representing a human readable
+ * error code from the lttcomm_return_code enum.
+ *
+ * These code MUST be negative in other to treat that
+ * as an error value.
+ */
+const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
+{
+ int tmp_code = -code;
+
+ if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
+ return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
+ }
+
+ return "Unknown error code";
+}
+
+/*
+ * lttcomm_connect_unix_sock
+ *
+ * Connect to unix socket using the path name.
+ */
+int lttcomm_connect_unix_sock(const char *pathname)
+{
+ struct sockaddr_un sun;
+ int fd;
+ int ret;
+
+ fd = socket(PF_UNIX, SOCK_STREAM, 0);
+ if (fd < 0) {
+ perror("socket");
+ ret = fd;
+ goto error;
+ }
+
+ memset(&sun, 0, sizeof(sun));
+ sun.sun_family = AF_UNIX;
+ strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
+ sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
+
+ ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
+ if (ret < 0) {
+ /*
+ * Don't print message on connect error, because connect
+ * is used in normal execution to detect if sessiond is
+ * alive.
+ */
+ goto error_connect;
+ }
+
+ return fd;
+
+error_connect:
+ close(fd);
+error:
+ return ret;
+}
+
+/*
+ * lttcomm_accept_unix_sock
+ *
+ * Do an accept(2) on the sock and return the
+ * new file descriptor. The socket MUST be bind(2) before.
+ */
+int lttcomm_accept_unix_sock(int sock)
+{
+ int new_fd;
+ struct sockaddr_un sun;
+ socklen_t len = 0;
+
+ /* Blocking call */
+ new_fd = accept(sock, (struct sockaddr *) &sun, &len);
+ if (new_fd < 0) {
+ perror("accept");
+ goto error;
+ }
+
+ return new_fd;
+
+error:
+ return -1;
+}
+
+/*
+ * lttcomm_create_unix_sock
+ *
+ * Creates a AF_UNIX local socket using pathname
+ * bind the socket upon creation and return the fd.
+ */
+int lttcomm_create_unix_sock(const char *pathname)
+{
+ struct sockaddr_un sun;
+ int fd;
+ int ret = -1;
+
+ /* Create server socket */
+ if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
+ perror("socket");
+ goto error;
+ }
+
+ memset(&sun, 0, sizeof(sun));
+ sun.sun_family = AF_UNIX;
+ strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
+ sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
+
+ /* Unlink the old file if present */
+ (void) unlink(pathname);
+ ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
+ if (ret < 0) {
+ perror("bind");
+ goto error;
+ }
+
+ return fd;
+
+error:
+ return ret;
+}
+
+/*
+ * lttcomm_listen_unix_sock
+ *
+ * Make the socket listen using MAX_LISTEN.
+ */
+int lttcomm_listen_unix_sock(int sock)
+{
+ int ret;
+
+ ret = listen(sock, MAX_LISTEN);
+ if (ret < 0) {
+ perror("listen");
+ }
+
+ return ret;
+}
+
+/*
+ * lttcomm_recv_unix_sock
+ *
+ * Receive data of size len in put that data into
+ * the buf param. Using recvmsg API.
+ * Return the size of received data.
+ */
+ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
+{
+ struct msghdr msg = { 0 };
+ struct iovec iov[1];
+ ssize_t ret = -1;
+
+ iov[0].iov_base = buf;
+ iov[0].iov_len = len;
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 1;
+
+ ret = recvmsg(sock, &msg, 0);
+ if (ret < 0) {
+ perror("recvmsg");
+ }
+
+ return ret;
+}
+
+/*
+ * lttcomm_send_unix_sock
+ *
+ * Send buf data of size len. Using sendmsg API.
+ * Return the size of sent data.
+ */
+ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
+{
+ struct msghdr msg = { 0 };
+ struct iovec iov[1];
+ ssize_t ret = -1;
+
+ iov[0].iov_base = buf;
+ iov[0].iov_len = len;
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 1;
+
+ ret = sendmsg(sock, &msg, 0);
+ if (ret < 0) {
+ perror("sendmsg");
+ }
+
+ return ret;
+}
+
+/*
+ * lttcomm_close_unix_sock
+ *
+ * Shutdown cleanly a unix socket.
+ */
+int lttcomm_close_unix_sock(int sock)
+{
+ int ret;
+
+ /* Shutdown receptions and transmissions */
+ ret = shutdown(sock, SHUT_RDWR);
+ if (ret < 0) {
+ perror("shutdown");
+ }
+
+ return ret;
+}
+
+/*
+ * lttcomm_send_fds_unix_sock
+ *
+ * Send multiple fds on a unix socket.
+ */
+ssize_t lttcomm_send_fds_unix_sock(int sock, void *buf, int *fds, size_t nb_fd, size_t len)
+{
+ struct msghdr msg = { 0 };
+ struct cmsghdr *cmptr;
+ struct iovec iov[1];
+ ssize_t ret = -1;
+ unsigned int sizeof_fds = nb_fd * sizeof(int);
+ char tmp[CMSG_SPACE(sizeof_fds)];
+
+ /*
+ * Note: the consumerd receiver only supports receiving one FD per
+ * message.
+ */
+ assert(nb_fd == 1);
+
+ msg.msg_control = (caddr_t)tmp;
+ msg.msg_controllen = CMSG_LEN(sizeof_fds);
+
+ cmptr = CMSG_FIRSTHDR(&msg);
+ cmptr->cmsg_level = SOL_SOCKET;
+ cmptr->cmsg_type = SCM_RIGHTS;
+ cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
+ memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
+ /* Sum of the length of all control messages in the buffer: */
+ msg.msg_controllen = cmptr->cmsg_len;
+
+ iov[0].iov_base = buf;
+ iov[0].iov_len = len;
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 1;
+
+ ret = sendmsg(sock, &msg, 0);
+ if (ret < 0) {
+ perror("sendmsg");
+ }
+
+ return ret;
+}