src/liblxc/execute.c

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2008
   5  *
   6  * Authors:
   7  * Daniel Lezcano <dlezcano at fr.ibm.com>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  22  */
  23 #define _GNU_SOURCE
  24 #include <stdio.h>
  25 #undef _GNU_SOURCE
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29 #include <errno.h>
  30 #include <signal.h>
  31 #include <fcntl.h>
  32 #include <sys/types.h>
  33 #include <sys/stat.h>
  34 #include <sys/param.h>
  35 #include <sys/prctl.h>
  36 #include <sys/wait.h>
  37 #include <sys/file.h>
  38 #include <sys/mount.h>
  39 #include <netinet/in.h>
  40 #include <net/if.h>
  41
  42 #include <lxc.h>
  43
  44 LXC_TTY_HANDLER(SIGINT);
  45 LXC_TTY_HANDLER(SIGQUIT);
  46
  47 int lxc_execute(const char *name, int argc, char *argv[],
  48                 lxc_callback_t preexec, void *data)
  49 {
  50         char *init = NULL, *val = NULL, *vinit = "[vinit]";
  51         int fd, lock, sv[2], sync = 0, err = -1;
  52         pid_t pid;
  53         int clone_flags;
  54
  55         lock = lxc_get_lock(name);
  56         if (!lock) {
  57                 lxc_log_error("'%s' is busy", name);
  58                 return -1;
  59         }
  60
  61         if (lock < 0) {
  62                 lxc_log_error("failed to acquire lock on '%s':%s",
  63                               name, strerror(-lock));
  64                 return -1;
  65         }
  66
  67         if (lxc_setstate(name, STARTING)) {
  68                 lxc_log_error("failed to set state %s", lxc_state2str(STARTING));
  69                 goto out;
  70         }
  71
  72         if (socketpair(AF_LOCAL, SOCK_STREAM, 0, sv)) {
  73                 lxc_log_syserror("failed to create communication socketpair");
  74                 goto err;
  75         }
  76
  77         LXC_TTY_ADD_HANDLER(SIGINT);
  78         LXC_TTY_ADD_HANDLER(SIGQUIT);
  79
  80         clone_flags = CLONE_NEWPID|CLONE_NEWIPC|CLONE_NEWNS;
  81         if (conf_has_utsname(name))
  82                 clone_flags |= CLONE_NEWUTS;
  83         if (conf_has_network(name))
  84                 clone_flags |= CLONE_NEWNET;
  85
  86         pid = fork_ns(clone_flags);
  87         if (pid < 0) {
  88                 lxc_log_syserror("failed to fork into a new namespace");
  89                 goto err_fork_ns;
  90         }
  91
  92         if (!pid) {
  93
  94                 pid = fork();
  95                 if (pid < 0) {
  96                         lxc_log_syserror("failed to fork");
  97                         return 1;
  98                 }
  99
 100                 if (!pid) {
 101                         close(sv[1]);
 102                         fcntl(sv[0], F_SETFD, FD_CLOEXEC);
 103
 104                         if (write(sv[0], &sync, sizeof(sync)) < 0) {
 105                                 lxc_log_syserror("failed to write socket");
 106                                 return 1;
 107                         }
 108
 109                         if (read(sv[0], &sync, sizeof(sync)) < 0) {
 110                                 lxc_log_syserror("failed to read socket");
 111                                 return 1;
 112                         }
 113
 114                         if (lxc_setup(name)) {
 115                                 lxc_log_error("failed to setup the container");
 116                                 goto error;
 117                         }
 118
 119                         if (mount("proc", "/proc", "proc", 0, NULL)) {
 120                                 lxc_log_syserror("failed to mount '/proc'");
 121                                 goto error;
 122                         }
 123
 124                         if (mount("sysfs", "/sys", "sysfs", 0, NULL)) {
 125                                 lxc_log_syserror("failed to mount '/sys'");
 126                                 /* continue: non fatal error until sysfs not per
 127                                  namespace */
 128                         }
 129
 130                         if (preexec)
 131                                 if (preexec(name, argc, argv, data)) {
 132                                         lxc_log_error("preexec callback has failed");
 133                                         return -1;
 134                                 }
 135
 136                         execvp(argv[0], argv);
 137                 error:
 138                         lxc_log_syserror("failed to exec %s", argv[0]);
 139                         if (write(sv[0], &sync, sizeof(sync)) < 0)
 140                                 lxc_log_syserror("failed to write the socket");
 141
 142                         return 1;
 143                 }
 144
 145                 setsid();
 146                 close(0);
 147                 close(1);
 148                 close(2);
 149
 150                 if (prctl(PR_SET_NAME, vinit, 0, 0, 0))
 151                         lxc_log_syserror("failed to set process name");
 152
 153                 close(sv[0]);
 154                 close(sv[1]);
 155
 156                 for (;;) {
 157                         int status;
 158                         if (wait(&status) < 0) {
 159                                 if (errno == ECHILD)
 160                                         return 0;
 161                                 if (errno == EINTR)
 162                                         continue;
 163                                 lxc_log_syserror("failed to wait child");
 164                                 return 1;
 165                         }
 166                 }
 167         }
 168
 169         close(sv[0]);
 170
 171         if (read(sv[1], &sync, sizeof(sync)) < 0) {
 172                 lxc_log_syserror("failed to read the socket");
 173                 goto err_pipe_read;
 174         }
 175
 176         if (clone_flags & CLONE_NEWNET && conf_create_network(name, pid)) {
 177                 lxc_log_error("failed to create the configured network");
 178                 goto err_create_network;
 179         }
 180
 181         if (write(sv[1], &sync, sizeof(sync)) < 0) {
 182                 lxc_log_syserror("failed to write the socket");
 183                 goto err_pipe_write;
 184         }
 185
 186         err = read(sv[1], &sync, sizeof(sync));
 187         if (err < 0) {
 188                 lxc_log_error("failed to read the socket");
 189                 goto err_pipe_read2;
 190         }
 191
 192         if (err > 0) {
 193                 lxc_log_error("something went wrong with %d", pid);
 194                 /* TODO : check status etc ... */
 195                 waitpid(pid, NULL, 0);
 196                 goto err_child_failed;
 197         }
 198
 199         asprintf(&init, LXCPATH "/%s/init", name);
 200         fd = open(init, O_WRONLY|O_CREAT, S_IRUSR|S_IWUSR);
 201         if (fd < 0) {
 202                 lxc_log_syserror("failed to open %s", init);
 203                 goto err_open;
 204         }
 205
 206         asprintf(&val, "%d", pid);
 207         if (write(fd, val, strlen(val)) < 0) {
 208                 lxc_log_syserror("failed to write init pid");
 209                 goto err_write;
 210         }
 211
 212         if (lxc_link_nsgroup(name, pid))
 213                 lxc_log_warning("cgroupfs not found: cgroup disabled");
 214
 215         if (lxc_setstate(name, RUNNING)) {
 216                 lxc_log_error("failed to set state to %s", lxc_state2str(RUNNING));
 217                 goto err_state_failed;
 218         }
 219
 220 wait_again:
 221         if (waitpid(pid, NULL, 0) < 0) {
 222                 if (errno == EINTR)
 223                         goto wait_again;
 224                 lxc_log_syserror("failed to wait the pid %d", pid);
 225                 goto err_waitpid_failed;
 226         }
 227
 228         if (lxc_setstate(name, STOPPING))
 229                 lxc_log_error("failed to set state %s", lxc_state2str(STOPPING));
 230
 231         if (clone_flags & CLONE_NEWNET && conf_destroy_network(name))
 232                 lxc_log_error("failed to destroy the network");
 233
 234         err = 0;
 235 out:
 236         if (lxc_setstate(name, STOPPED))
 237                 lxc_log_error("failed to set state %s", lxc_state2str(STOPPED));
 238
 239         lxc_unlink_nsgroup(name);
 240         unlink(init);
 241         free(init);
 242         free(val);
 243         lxc_put_lock(lock);
 244
 245         return err;
 246
 247 err_write:
 248         close(fd);
 249
 250 err_state_failed:
 251 err_child_failed:
 252 err_pipe_read2:
 253 err_pipe_write:
 254         conf_destroy_network(name);
 255 err_create_network:
 256 err_pipe_read:
 257 err_open:
 258 err_waitpid_failed:
 259         if (lxc_setstate(name, ABORTING))
 260                 lxc_log_error("failed to set state %s", lxc_state2str(STOPPED));
 261
 262         kill(pid, SIGKILL);
 263 err_fork_ns:
 264         LXC_TTY_DEL_HANDLER(SIGQUIT);
 265         LXC_TTY_DEL_HANDLER(SIGINT);
 266         close(sv[0]);
 267         close(sv[1]);
 268 err:
 269         goto out;
 270 }