1 files changed, 104 insertions, 0 deletions
diff --git a/src/libsystemd/sd-bus/bus-container.c b/src/libsystemd/sd-bus/bus-container.c
new file mode 100644
index 0000000..b3c0279
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-container.c
@@ -0,0 +1,104 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "bus-container.h"
+#include "bus-internal.h"
+#include "bus-socket.h"
+#include "fd-util.h"
+#include "namespace-util.h"
+#include "process-util.h"
+#include "string-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) {
+                log_debug("sd-bus: connecting bus%s%s to machine %s...",
+                          b->description ? " " : "", strempty(b->description), b->machine);
+
+                r = container_get_leader(b->machine, &b->nspid);
+                if (r < 0)
+                        return r;
+        } else
+                log_debug("sd-bus: connecting bus%s%s to namespace of PID "PID_FMT"...",
+                          b->description ? " " : "", strempty(b->description), b->nspid);
+
+        r = namespace_open(b->nspid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to open namespace of PID "PID_FMT": %m", b->nspid);
+
+        b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (b->input_fd < 0)
+                return log_debug_errno(errno, "Failed to create a socket: %m");
+
+        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|SOCK_CLOEXEC, 0, pair) < 0)
+                return log_debug_errno(errno, "Failed to create a socket pair: %m");
+
+        r = namespace_fork("(sd-buscntrns)", "(sd-buscntr)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG,
+                           pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to create namespace for (sd-buscntr): %m");
+        if (r == 0) {
+                pair[0] = safe_close(pair[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);
+        }
+
+        pair[1] = safe_close(pair[1]);
+
+        r = wait_for_terminate_and_check("(sd-buscntrns)", child, 0);
+        if (r < 0)
+                return r;
+        bool nonzero_exit_status = r != EXIT_SUCCESS;
+
+        n = read(pair[0], &error_buf, sizeof(error_buf));
+        if (n < 0)
+                return log_debug_errno(errno, "Failed to read error status from (sd-buscntr): %m");
+
+        if (n > 0) {
+                if (n != sizeof(error_buf))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EIO),
+                                               "Read error status of unexpected length %zd from (sd-buscntr): %m", n);
+
+                if (error_buf < 0)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Got unexpected error status from (sd-buscntr): %m");
+
+                if (error_buf == EINPROGRESS)
+                        return 1;
+
+                if (error_buf > 0)
+                        return log_debug_errno(error_buf, "(sd-buscntr) failed to connect to D-Bus socket: %m");
+        }
+
+        if (nonzero_exit_status)
+                return -EPROTO;
+
+        return bus_socket_start_auth(b);
+}