149 lines
3.4 KiB
C
149 lines
3.4 KiB
C
/*
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* Copyright © 2012 Keith Packard <keithp@keithp.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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*/
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#include "fdpass.h"
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#define MAX_FDS 128
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struct fd_pass {
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struct cmsghdr cmsghdr;
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int fd[MAX_FDS];
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};
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ssize_t
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sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd, int *nfdp)
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{
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ssize_t size;
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printf ("sock_fd_read\n");
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if (fd) {
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struct msghdr msg;
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struct iovec iov;
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struct fd_pass pass;
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int nfd_passed, nfd;
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int i;
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int *fd_passed;
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iov.iov_base = buf;
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iov.iov_len = bufsize;
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msg.msg_name = NULL;
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msg.msg_namelen = 0;
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msg.msg_iov = &iov;
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msg.msg_iovlen = 1;
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msg.msg_control = &pass;
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msg.msg_controllen = sizeof pass;
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size = recvmsg (sock, &msg, 0);
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if (size < 0) {
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perror ("recvmsg");
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exit(1);
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}
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if (size > 0 && pass.cmsghdr.cmsg_len > sizeof (struct cmsghdr)) {
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if ((msg.msg_flags & MSG_TRUNC) ||
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(msg.msg_flags & MSG_CTRUNC)) {
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fprintf (stderr, "control message truncated");
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exit(1);
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}
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if (pass.cmsghdr.cmsg_level != SOL_SOCKET) {
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fprintf (stderr, "invalid cmsg_level %d\n",
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pass.cmsghdr.cmsg_level);
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exit(1);
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}
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if (pass.cmsghdr.cmsg_type != SCM_RIGHTS) {
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fprintf (stderr, "invalid cmsg_type %d\n",
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pass.cmsghdr.cmsg_type);
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exit(1);
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}
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nfd_passed = (pass.cmsghdr.cmsg_len - sizeof (struct cmsghdr)) / sizeof (int);
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fd_passed = (int *) CMSG_DATA(&pass.cmsghdr);
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nfd = *nfdp;
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if (nfd > nfd_passed)
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nfd = nfd_passed;
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memcpy(fd, fd_passed, nfd * sizeof (int));
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for (i = 0; i < nfd; i++)
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printf ("received fd %d\n", fd[i]);
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for (i = nfd; i < nfd_passed; i++) {
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printf ("dropping fd %d\n", fd_passed[i]);
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close(fd_passed[i]);
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}
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*nfdp = nfd;
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} else
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*nfdp = 0;
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} else {
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size = read (sock, buf, bufsize);
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if (size < 0) {
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perror("read");
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exit(1);
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}
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}
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return size;
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}
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ssize_t
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sock_fd_write(int sock, void *buf, ssize_t buflen, int *fd, int nfd)
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{
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ssize_t size;
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struct msghdr msg;
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struct iovec iov;
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struct fd_pass pass;
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int i;
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iov.iov_base = buf;
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iov.iov_len = buflen;
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msg.msg_name = NULL;
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msg.msg_namelen = 0;
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if (buflen) {
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msg.msg_iov = &iov;
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msg.msg_iovlen = 1;
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} else {
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msg.msg_iov = NULL;
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msg.msg_iovlen = 0;
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}
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if (nfd) {
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if (nfd > MAX_FDS) {
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printf ("passing too many fds\n");
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exit(1);
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}
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msg.msg_control = &pass;
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msg.msg_controllen = sizeof (struct cmsghdr) + nfd * sizeof (int);
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pass.cmsghdr.cmsg_len = msg.msg_controllen;
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pass.cmsghdr.cmsg_level = SOL_SOCKET;
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pass.cmsghdr.cmsg_type = SCM_RIGHTS;
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memcpy(&pass.fd, fd, nfd * sizeof (int));
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for (i = 0; i < nfd; i++)
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printf ("passing fd %d\n", pass.fd[i]);
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} else {
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msg.msg_control = NULL;
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msg.msg_controllen = 0;
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printf ("not passing fd\n");
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}
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size = sendmsg(sock, &msg, 0);
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if (size < 0)
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perror ("sendmsg");
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return size;
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}
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