bus: add API call to create bus connection to the system bus of local containers

[elogind.git] / src / libsystemd-bus / bus-container.c

diff --git a/src/libsystemd-bus/bus-container.c b/src/libsystemd-bus/bus-container.c
new file mode 100644 (file)
index 0000000..eac1863
--- /dev/null
+++ b/src/libsystemd-bus/bus-container.c
@@ -0,0 +1,128 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "util.h"
+#include "fileio.h"
+#include "bus-internal.h"
+#include "bus-socket.h"
+#include "bus-container.h"
+
+int bus_container_connect(sd_bus *b) {
+        _cleanup_free_ char *p = NULL, *s = NULL, *ns = NULL, *root = NULL, *class = NULL;
+        _cleanup_close_ int nsfd = -1, rootfd = -1;
+        siginfo_t si;
+        pid_t leader, child;
+        int r;
+
+        assert(b);
+        assert(b->input_fd < 0);
+        assert(b->output_fd < 0);
+
+        p = strappend("/run/systemd/machines/", b->machine);
+        if (!p)
+                return -ENOMEM;
+
+        r = parse_env_file(p, NEWLINE, "LEADER", &s, "CLASS", &class, NULL);
+        if (r < 0)
+                return r;
+        if (!s)
+                return -EIO;
+
+        if (!streq_ptr(class, "container"))
+                return -EIO;
+
+        r = parse_pid(s, &leader);
+        if (r < 0)
+                return r;
+        if (leader <= 1)
+                return -EIO;
+
+        r = asprintf(&ns, "/proc/%lu/ns/mnt", (unsigned long) leader);
+        if (r < 0)
+                return -ENOMEM;
+
+        nsfd = open(ns, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+        if (nsfd < 0)
+                return -errno;
+
+        r = asprintf(&root, "/proc/%lu/root", (unsigned long) leader);
+        if (r < 0)
+                return -ENOMEM;
+
+        rootfd = open(root, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+        if (rootfd < 0)
+                return -errno;
+
+        b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (b->input_fd < 0)
+                return -errno;
+
+        b->output_fd = b->input_fd;
+
+        r = bus_socket_setup(b);
+        if (r < 0)
+                return r;
+
+        child = fork();
+        if (child < 0)
+                return -errno;
+
+        if (child == 0) {
+                r = setns(nsfd, CLONE_NEWNS);
+                if (r < 0)
+                        _exit(255);
+
+                if (fchdir(rootfd) < 0)
+                        _exit(255);
+
+                if (chroot(".") < 0)
+                        _exit(255);
+
+
+                r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size);
+                if (r < 0) {
+                        if (errno == EINPROGRESS)
+                                _exit(1);
+
+                        _exit(255);
+                }
+
+                _exit(0);
+        }
+
+        r = wait_for_terminate(child, &si);
+        if (r < 0)
+                return r;
+
+        if (si.si_code != CLD_EXITED)
+                return -EIO;
+
+        if (si.si_status == 1)
+                return 1;
+
+        if (si.si_status != 0)
+                return -EIO;
+
+        return bus_socket_start_auth(b);
+}