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/*
* Unix SMB/CIFS implementation.
* Copyright (C) Volker Lendecke 2014
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include "replace.h"
#include "lib/msghdr.h"
#include "lib/util/iov_buf.h"
#include <sys/socket.h>
ssize_t msghdr_prep_fds(struct msghdr *msg, uint8_t *buf, size_t bufsize,
const int *fds, size_t num_fds)
{
size_t fds_size = sizeof(int) * MIN(num_fds, INT8_MAX);
size_t cmsg_len = CMSG_LEN(fds_size);
size_t cmsg_space = CMSG_SPACE(fds_size);
struct cmsghdr *cmsg;
void *fdptr;
if (num_fds == 0) {
if (msg != NULL) {
msg->msg_control = NULL;
msg->msg_controllen = 0;
}
return 0;
}
if (num_fds > INT8_MAX) {
return -1;
}
if ((msg == NULL) || (cmsg_space > bufsize)) {
return cmsg_space;
}
msg->msg_control = buf;
msg->msg_controllen = cmsg_space;
cmsg = CMSG_FIRSTHDR(msg);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = cmsg_len;
fdptr = CMSG_DATA(cmsg);
memcpy(fdptr, fds, fds_size);
msg->msg_controllen = cmsg->cmsg_len;
return cmsg_space;
}
struct msghdr_buf {
struct msghdr msg;
struct sockaddr_storage addr;
struct iovec iov;
uint8_t buf[];
};
ssize_t msghdr_copy(struct msghdr_buf *msg, size_t msgsize,
const void *addr, socklen_t addrlen,
const struct iovec *iov, int iovcnt,
const int *fds, size_t num_fds)
{
ssize_t fd_len;
size_t iov_len, needed, bufsize;
bufsize = (msgsize > offsetof(struct msghdr_buf, buf)) ?
msgsize - offsetof(struct msghdr_buf, buf) : 0;
fd_len = msghdr_prep_fds(&msg->msg, msg->buf, bufsize, fds, num_fds);
if (fd_len == -1) {
return -1;
}
if (bufsize >= fd_len) {
bufsize -= fd_len;
} else {
bufsize = 0;
}
if (msg != NULL) {
if (addr != NULL) {
if (addrlen > sizeof(struct sockaddr_storage)) {
errno = EMSGSIZE;
return -1;
}
memcpy(&msg->addr, addr, addrlen);
msg->msg.msg_name = &msg->addr;
msg->msg.msg_namelen = addrlen;
} else {
msg->msg.msg_name = NULL;
msg->msg.msg_namelen = 0;
}
msg->iov.iov_base = msg->buf + fd_len;
msg->iov.iov_len = iov_buf(
iov, iovcnt, msg->iov.iov_base, bufsize);
iov_len = msg->iov.iov_len;
msg->msg.msg_iov = &msg->iov;
msg->msg.msg_iovlen = 1;
} else {
iov_len = iov_buflen(iov, iovcnt);
}
needed = offsetof(struct msghdr_buf, buf) + fd_len;
if (needed < fd_len) {
return -1;
}
needed += iov_len;
if (needed < iov_len) {
return -1;
}
return needed;
}
struct msghdr *msghdr_buf_msghdr(struct msghdr_buf *msg)
{
return &msg->msg;
}
size_t msghdr_prep_recv_fds(struct msghdr *msg, uint8_t *buf, size_t bufsize,
size_t num_fds)
{
size_t ret = CMSG_SPACE(sizeof(int) * num_fds);
if (bufsize < ret) {
return ret;
}
if (msg != NULL) {
if (num_fds != 0) {
msg->msg_control = buf;
msg->msg_controllen = ret;
} else {
msg->msg_control = NULL;
msg->msg_controllen = 0;
}
}
return ret;
}
size_t msghdr_extract_fds(struct msghdr *msg, int *fds, size_t fds_size)
{
struct cmsghdr *cmsg;
size_t num_fds;
for(cmsg = CMSG_FIRSTHDR(msg);
cmsg != NULL;
cmsg = CMSG_NXTHDR(msg, cmsg))
{
if ((cmsg->cmsg_type == SCM_RIGHTS) &&
(cmsg->cmsg_level == SOL_SOCKET)) {
break;
}
}
if (cmsg == NULL) {
return 0;
}
num_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
if ((num_fds != 0) && (fds != NULL) && (fds_size >= num_fds)) {
memcpy(fds, CMSG_DATA(cmsg), num_fds * sizeof(int));
}
return num_fds;
}
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