src/libsystemd-bus/bus-container.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2013 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <unistd.h>
  23 #include <fcntl.h>
  24
  25 #include "util.h"
  26 #include "fileio.h"
  27 #include "bus-internal.h"
  28 #include "bus-socket.h"
  29 #include "bus-container.h"
  30
  31 int bus_container_connect(sd_bus *b) {
  32         _cleanup_free_ char *p = NULL, *s = NULL, *ns = NULL, *root = NULL, *class = NULL;
  33         _cleanup_close_ int nsfd = -1, rootfd = -1;
  34         siginfo_t si;
  35         pid_t leader, child;
  36         int r;
  37
  38         assert(b);
  39         assert(b->input_fd < 0);
  40         assert(b->output_fd < 0);
  41
  42         p = strappend("/run/systemd/machines/", b->machine);
  43         if (!p)
  44                 return -ENOMEM;
  45
  46         r = parse_env_file(p, NEWLINE, "LEADER", &s, "CLASS", &class, NULL);
  47         if (r == -ENOENT)
  48                 return -EHOSTDOWN;
  49         if (r < 0)
  50                 return r;
  51         if (!s)
  52                 return -EIO;
  53
  54         if (!streq_ptr(class, "container"))
  55                 return -EIO;
  56
  57         r = parse_pid(s, &leader);
  58         if (r < 0)
  59                 return r;
  60         if (leader <= 1)
  61                 return -EIO;
  62
  63         r = asprintf(&ns, "/proc/%lu/ns/mnt", (unsigned long) leader);
  64         if (r < 0)
  65                 return -ENOMEM;
  66
  67         nsfd = open(ns, O_RDONLY|O_NOCTTY|O_CLOEXEC);
  68         if (nsfd < 0)
  69                 return -errno;
  70
  71         r = asprintf(&root, "/proc/%lu/root", (unsigned long) leader);
  72         if (r < 0)
  73                 return -ENOMEM;
  74
  75         rootfd = open(root, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
  76         if (rootfd < 0)
  77                 return -errno;
  78
  79         b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
  80         if (b->input_fd < 0)
  81                 return -errno;
  82
  83         b->output_fd = b->input_fd;
  84
  85         r = bus_socket_setup(b);
  86         if (r < 0)
  87                 return r;
  88
  89         child = fork();
  90         if (child < 0)
  91                 return -errno;
  92
  93         if (child == 0) {
  94                 r = setns(nsfd, CLONE_NEWNS);
  95                 if (r < 0)
  96                         _exit(255);
  97
  98                 if (fchdir(rootfd) < 0)
  99                         _exit(255);
 100
 101                 if (chroot(".") < 0)
 102                         _exit(255);
 103
 104                 r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size);
 105                 if (r < 0) {
 106                         if (errno == EINPROGRESS)
 107                                 _exit(1);
 108
 109                         _exit(255);
 110                 }
 111
 112                 _exit(0);
 113         }
 114
 115         r = wait_for_terminate(child, &si);
 116         if (r < 0)
 117                 return r;
 118
 119         if (si.si_code != CLD_EXITED)
 120                 return -EIO;
 121
 122         if (si.si_status == 1)
 123                 return 1;
 124
 125         if (si.si_status != 0)
 126                 return -EIO;
 127
 128         return bus_socket_start_auth(b);
 129 }