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 *s = NULL, *ns = NULL, *root = NULL, *class = NULL;
  33         _cleanup_close_ int nsfd = -1, rootfd = -1;
  34         char *p;
  35         siginfo_t si;
  36         pid_t leader, child;
  37         int r;
  38
  39         assert(b);
  40         assert(b->input_fd < 0);
  41         assert(b->output_fd < 0);
  42
  43         p = strappenda("/run/systemd/machines/", b->machine);
  44         r = parse_env_file(p, NEWLINE, "LEADER", &s, "CLASS", &class, NULL);
  45         if (r == -ENOENT)
  46                 return -EHOSTDOWN;
  47         if (r < 0)
  48                 return r;
  49         if (!s)
  50                 return -EIO;
  51
  52         if (!streq_ptr(class, "container"))
  53                 return -EIO;
  54
  55         r = parse_pid(s, &leader);
  56         if (r < 0)
  57                 return r;
  58         if (leader <= 1)
  59                 return -EIO;
  60
  61         r = asprintf(&ns, "/proc/%lu/ns/mnt", (unsigned long) leader);
  62         if (r < 0)
  63                 return -ENOMEM;
  64
  65         nsfd = open(ns, O_RDONLY|O_NOCTTY|O_CLOEXEC);
  66         if (nsfd < 0)
  67                 return -errno;
  68
  69         r = asprintf(&root, "/proc/%lu/root", (unsigned long) leader);
  70         if (r < 0)
  71                 return -ENOMEM;
  72
  73         rootfd = open(root, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
  74         if (rootfd < 0)
  75                 return -errno;
  76
  77         b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
  78         if (b->input_fd < 0)
  79                 return -errno;
  80
  81         b->output_fd = b->input_fd;
  82
  83         r = bus_socket_setup(b);
  84         if (r < 0)
  85                 return r;
  86
  87         child = fork();
  88         if (child < 0)
  89                 return -errno;
  90
  91         if (child == 0) {
  92                 r = setns(nsfd, CLONE_NEWNS);
  93                 if (r < 0)
  94                         _exit(255);
  95
  96                 if (fchdir(rootfd) < 0)
  97                         _exit(255);
  98
  99                 if (chroot(".") < 0)
 100                         _exit(255);
 101
 102                 r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size);
 103                 if (r < 0) {
 104                         if (errno == EINPROGRESS)
 105                                 _exit(1);
 106
 107                         _exit(255);
 108                 }
 109
 110                 _exit(0);
 111         }
 112
 113         r = wait_for_terminate(child, &si);
 114         if (r < 0)
 115                 return r;
 116
 117         if (si.si_code != CLD_EXITED)
 118                 return -EIO;
 119
 120         if (si.si_status == 1)
 121                 return 1;
 122
 123         if (si.si_status != 0)
 124                 return -EIO;
 125
 126         return bus_socket_start_auth(b);
 127 }