From: Mathieu Desnoyers Date: Thu, 11 Aug 2011 23:28:06 +0000 (-0400) Subject: Merge copy of lttng-sessiond-comm X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=67c5b804ac870bdc3b262c0cf6cbf117f3e6bc1e;p=ust.git Merge copy of lttng-sessiond-comm Signed-off-by: Mathieu Desnoyers --- diff --git a/Makefile.am b/Makefile.am index b72f9fa..b163bf8 100644 --- a/Makefile.am +++ b/Makefile.am @@ -5,7 +5,7 @@ ACLOCAL_AMFLAGS = -I config # libust and '.' (that contains the linker script). However, '.' # must be installed after libust so it can overwrite libust.so with # the linker script. -SUBDIRS = snprintf libringbuffer libust include doc tests +SUBDIRS = snprintf liblttng-sessiond-comm libringbuffer libust include doc tests #temporarily disabled # . libustinstr-malloc libustfork diff --git a/configure.ac b/configure.ac index 6fdb279..9926d73 100644 --- a/configure.ac +++ b/configure.ac @@ -141,6 +141,7 @@ AC_CONFIG_FILES([ doc/man/Makefile doc/info/Makefile include/Makefile + liblttng-sessiond-comm/Makefile libringbuffer/Makefile libust/Makefile tests/Makefile diff --git a/include/Makefile.am b/include/Makefile.am index 856be02..3361b4e 100644 --- a/include/Makefile.am +++ b/include/Makefile.am @@ -16,6 +16,7 @@ nobase_include_HEADERS = \ # note: usterr-signal-safe.h, core.h and share.h need namespace cleanup. noinst_HEADERS = \ + lttng-sessiond-comm.h \ usterr.h \ ust_snprintf.h \ ust/compat.h \ diff --git a/include/lttng-sessiond-comm.h b/include/lttng-sessiond-comm.h new file mode 100644 index 0000000..be903a6 --- /dev/null +++ b/include/lttng-sessiond-comm.h @@ -0,0 +1,210 @@ +#ifndef _LTTNG_SESSIOND_COMM_H +#define _LTTNG_SESSIOND_COMM_H + +/* + * Copyright (C) 2011 - David Goulet + * Julien Desfossez + * Mathieu Desnoyers + * + * 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 +#include + +#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 */ diff --git a/liblttng-sessiond-comm/Makefile.am b/liblttng-sessiond-comm/Makefile.am new file mode 100644 index 0000000..5ddd39c --- /dev/null +++ b/liblttng-sessiond-comm/Makefile.am @@ -0,0 +1,6 @@ +AM_CPPFLAGS = -I$(top_srcdir)/include + +noinst_LTLIBRARIES = liblttng-sessiond-comm.la + +liblttng_sessiond_comm_la_SOURCES = lttng-sessiond-comm.c \ + lttng-sessiond-comm.h diff --git a/liblttng-sessiond-comm/lttng-sessiond-comm.c b/liblttng-sessiond-comm/lttng-sessiond-comm.c new file mode 100644 index 0000000..e370fcd --- /dev/null +++ b/liblttng-sessiond-comm/lttng-sessiond-comm.c @@ -0,0 +1,340 @@ +/* + * Copyright (C) 2011 - David Goulet + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +/* + * 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; +}