src/lib/fdpass.c

	fdpass.c revision d965dc8785aeb06eb504e88796d532e5084d23cd
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen/*
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen fdpass.c - FD passing
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    Copyright (c) 2002 Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    Permission is hereby granted, free of charge, to any person obtaining
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    a copy of this software and associated documentation files (the
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    "Software"), to deal in the Software without restriction, including
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    without limitation the rights to use, copy, modify, merge, publish,
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    distribute, sublicense, and/or sell copies of the Software, and to
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    permit persons to whom the Software is furnished to do so, subject to
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    the following conditions:
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    The above copyright notice and this permission notice shall be
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    included in all copies or substantial portions of the Software.
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen*/
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen#define _XPG4_2
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen#include "lib.h"
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen#include "fdpass.h"
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen#include <sys/socket.h>
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen#include <sys/un.h>
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen#include <sys/uio.h>
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen#ifndef CMSG_SPACE
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen#  define CMSG_ALIGN(len) \
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    (((len) + sizeof(size_t) - 1) & ~(sizeof(size_t) - 1))
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen#  define CMSG_SPACE(len) \
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    (CMSG_ALIGN(len) + CMSG_ALIGN(sizeof(struct cmsghdr)))
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen#  define CMSG_LEN(len) \
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    (CMSG_ALIGN(sizeof(struct cmsghdr)) + (len))
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen#endif
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainenssize_t fd_send(int handle, int send_fd, const void *data, size_t size)
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen{
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        struct msghdr msg;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        struct iovec iov;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        struct cmsghdr *cmsg;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    char buf[CMSG_SPACE(sizeof(int))];
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    /* at least one byte is required to be sent with fd passing */
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    i_assert(size > 0 && size < SSIZE_T_MAX);
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    memset(&msg, 0, sizeof (struct msghdr));
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        iov.iov_base = (void *) data;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        iov.iov_len = size;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        msg.msg_iov = &iov;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    msg.msg_iovlen = 1;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    if (send_fd != -1) {
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        /* set the control and controllen before CMSG_FIRSTHDR() */
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        msg.msg_control = buf;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        msg.msg_controllen = sizeof(buf);
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        cmsg = CMSG_FIRSTHDR(&msg);
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        cmsg->cmsg_level = SOL_SOCKET;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        cmsg->cmsg_type = SCM_RIGHTS;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        cmsg->cmsg_len = CMSG_LEN(sizeof(int));
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        *((int *) CMSG_DATA(cmsg)) = send_fd;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        /* set the real length we want to use. it's different than
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen           sizeof(buf) in 64bit systems. */
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        msg.msg_controllen = cmsg->cmsg_len;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    }
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    return sendmsg(handle, &msg, 0);
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen}
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainenssize_t fd_read(int handle, void *data, size_t size, int *fd)
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen{
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    struct msghdr msg;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    struct iovec iov;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    struct cmsghdr *cmsg;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    ssize_t ret;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    char buf[CMSG_SPACE(sizeof(int))];
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    i_assert(size > 0 && size < SSIZE_T_MAX);
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    memset(&msg, 0, sizeof (struct msghdr));
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    iov.iov_base = data;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    iov.iov_len = size;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    msg.msg_iov = &iov;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    msg.msg_iovlen = 1;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    msg.msg_control = buf;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    msg.msg_controllen = sizeof(buf);
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    ret = recvmsg(handle, &msg, 0);
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    if (ret <= 0)
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        return ret;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    /* at least one byte transferred - we should have the fd now */
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    cmsg = CMSG_FIRSTHDR(&msg);
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    if (cmsg == NULL)
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        *fd = -1;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    else
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen        *fd = *((int *) CMSG_DATA(cmsg));
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen    return ret;
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen}
8aeae03f9f447c8a792b215c9fb954468053c556Timo Sirainen