src/lxc/console.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
  24 #include <stdio.h>
  25 #include <unistd.h>
  26 #include <errno.h>
  27 #include <sys/types.h>
  28 #include <sys/un.h>
  29
  30 #include "af_unix.h"
  31 #include "error.h"
  32
  33 #include <lxc/log.h>
  34 #include "commands.h"
  35
  36 lxc_log_define(lxc_console, lxc);
  37
  38 static int receive_answer(int sock, struct lxc_answer *answer)
  39 {
  40         int ret;
  41
  42         ret = lxc_af_unix_recv_fd(sock, &answer->fd, answer, sizeof(*answer));
  43         if (ret < 0)
  44                 ERROR("failed to receive answer for the command");
  45
  46         return ret;
  47 }
  48
  49 static int send_command(const char *name, struct lxc_command *command)
  50 {
  51         struct sockaddr_un addr = { 0 };
  52         int sock, ret = -1;
  53         char *offset = &addr.sun_path[1];
  54
  55         snprintf(addr.sun_path, sizeof(addr.sun_path), "@%s", name);
  56         addr.sun_path[0] = '\0';
  57
  58         sock = lxc_af_unix_connect(addr.sun_path);
  59         if (sock < 0) {
  60                 WARN("failed to connect to '@%s': %s", offset, strerror(errno));
  61                 return -1;
  62         }
  63
  64         ret = lxc_af_unix_send_credential(sock, &command->request,
  65                                         sizeof(command->request));
  66         if (ret < 0) {
  67                 SYSERROR("failed to send credentials");
  68                 goto out_close;
  69         }
  70
  71         if (ret != sizeof(command->request)) {
  72                 SYSERROR("message only partially sent to '@%s'", offset);
  73                 goto out_close;
  74         }
  75
  76         ret = receive_answer(sock, &command->answer);
  77         if (ret < 0)
  78                 goto out_close;
  79 out:
  80         return ret;
  81 out_close:
  82         close(sock);
  83         goto out;
  84 }
  85
  86 extern int lxc_console(const char *name, int ttynum, int *fd)
  87 {
  88         int ret;
  89         struct lxc_command command = {
  90                 .request = { .type = LXC_COMMAND_TTY, .data = ttynum },
  91         };
  92
  93         ret = send_command(name, &command);
  94         if (ret < 0) {
  95                 ERROR("failed to send command");
  96                 return -1;
  97         }
  98
  99         if (!ret) {
 100                 ERROR("console denied by '%s'", name);
 101                 return -1;
 102         }
 103
 104         *fd = command.answer.fd;
 105         if (*fd <0) {
 106                 ERROR("unable to allocate fd for tty %d", ttynum);
 107                 return -1;
 108         }
 109
 110         INFO("tty %d allocated", ttynum);
 111         return 0;
 112 }