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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
***/
#include <fcntl.h>
#include <unistd.h>
#include "bus-container.h"
#include "bus-internal.h"
#include "bus-socket.h"
#include "fd-util.h"
#include "process-util.h"
#include "util.h"
int bus_container_connect_socket(sd_bus *b) {
_cleanup_close_pair_ int pair[2] = { -1, -1 };
_cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
int r, error_buf = 0;
pid_t child;
ssize_t n;
assert(b);
assert(b->input_fd < 0);
assert(b->output_fd < 0);
assert(b->nspid > 0 || b->machine);
if (b->nspid <= 0) {
r = container_get_leader(b->machine, &b->nspid);
if (r < 0)
return r;
}
r = namespace_open(b->nspid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
if (r < 0)
return r;
b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (b->input_fd < 0)
return -errno;
b->input_fd = fd_move_above_stdio(b->input_fd);
b->output_fd = b->input_fd;
bus_socket_setup(b);
if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, pair) < 0)
return -errno;
r = safe_fork("(sd-buscntr)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child);
if (r < 0)
return r;
if (r == 0) {
pid_t grandchild;
pair[0] = safe_close(pair[0]);
r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
if (r < 0)
_exit(EXIT_FAILURE);
/* We just changed PID namespace, however it will only
* take effect on the children we now fork. Hence,
* let's fork another time, and connect from this
* grandchild, so that SO_PEERCRED of our connection
* comes from a process from within the container, and
* not outside of it */
r = safe_fork("(sd-buscntr2)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &grandchild);
if (r < 0)
_exit(EXIT_FAILURE);
if (r == 0) {
r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size);
if (r < 0) {
/* Try to send error up */
error_buf = errno;
(void) write(pair[1], &error_buf, sizeof(error_buf));
_exit(EXIT_FAILURE);
}
_exit(EXIT_SUCCESS);
}
r = wait_for_terminate_and_check("(sd-buscntr2)", grandchild, 0);
if (r < 0)
_exit(EXIT_FAILURE);
_exit(r);
}
pair[1] = safe_close(pair[1]);
r = wait_for_terminate_and_check("(sd-buscntr)", child, 0);
if (r < 0)
return r;
if (r != EXIT_SUCCESS)
return -EPROTO;
n = read(pair[0], &error_buf, sizeof(error_buf));
if (n < 0)
return -errno;
if (n > 0) {
if (n != sizeof(error_buf))
return -EIO;
if (error_buf < 0)
return -EIO;
if (error_buf == EINPROGRESS)
return 1;
if (error_buf > 0)
return -error_buf;
}
return bus_socket_start_auth(b);
}
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