src/lxc/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 #define _GNU_SOURCE
  25 #include <stdio.h>
  26 #undef _GNU_SOURCE
  27 #include <stdlib.h>
  28 #include <errno.h>
  29 #include <string.h>
  30 #include <fcntl.h>
  31 #include <termios.h>
  32 #include <unistd.h>
  33 #include <signal.h>
  34 #include <libgen.h>
  35 #include <sys/param.h>
  36 #include <sys/types.h>
  37 #include <sys/stat.h>
  38 #include <sys/poll.h>
  39
  40 #include "error.h"
  41 #include "lxc.h"
  42
  43 void usage(char *cmd)
  44 {
  45         fprintf(stderr, "%s <command>\n", basename(cmd));
  46         fprintf(stderr, "\t -n <name>   : name of the container\n");
  47         fprintf(stderr, "\t -t <tty#>   : tty number\n");
  48         _exit(1);
  49 }
  50
  51 int main(int argc, char *argv[])
  52 {
  53         char opt;
  54         char *name = NULL;
  55         int ttynum = 0;
  56         int nbargs = 0;
  57         int master = -1;
  58         int wait4q = 0;
  59         int err = LXC_ERROR_INTERNAL;
  60         struct termios tios, oldtios;
  61
  62         while ((opt = getopt(argc, argv, "t:n:")) != -1) {
  63                 switch (opt) {
  64                 case 'n':
  65                         name = optarg;
  66                         break;
  67                 case 't':
  68                         ttynum = atoi(optarg);
  69                         break;
  70                 }
  71
  72                 nbargs++;
  73         }
  74
  75         if (!name || !ttynum)
  76                 usage(argv[0]);
  77
  78         /* Get current termios */
  79         if (tcgetattr(0, &tios)) {
  80                 lxc_log_error("failed to get current terminal settings");
  81                 fprintf(stderr, "%s\n", lxc_strerror(err));
  82                 return 1;
  83         }
  84
  85         oldtios = tios;
  86
  87         /* Remove the echo characters and signal reception, the echo
  88          * will be done below with master proxying */
  89         tios.c_iflag &= ~IGNBRK;
  90         tios.c_iflag &= BRKINT;
  91         tios.c_lflag &= ~(ECHO|ICANON|ISIG);
  92         tios.c_cc[VMIN] = 1;
  93         tios.c_cc[VTIME] = 0;
  94
  95         /* Set new attributes */
  96         if (tcsetattr(0, TCSAFLUSH, &tios)) {
  97                 lxc_log_syserror("failed to set new terminal settings");
  98                 fprintf(stderr, "%s\n", lxc_strerror(err));
  99                 return 1;
 100         }
 101
 102         err = lxc_console(name, ttynum, &master);
 103         if (err) {
 104                 fprintf(stderr, "%s\n", lxc_strerror(err));
 105                 goto out;
 106         }
 107
 108         fprintf(stderr, "\nType <Ctrl+a q> to exit the console\n");
 109
 110         setsid();
 111
 112         err = 0;
 113
 114         /* let's proxy the tty */
 115         for (;;) {
 116                 char c;
 117                 struct pollfd pfd[2] = {
 118                         { .fd = 0,
 119                           .events = POLLIN|POLLPRI,
 120                           .revents = 0 },
 121                         { .fd = master,
 122                           .events = POLLIN|POLLPRI,
 123                           .revents = 0 },
 124                 };
 125
 126                 if (poll(pfd, 2, -1) < 0) {
 127                         if (errno == EINTR)
 128                                 continue;
 129                         lxc_log_syserror("failed to poll");
 130                         goto out_err;
 131                 }
 132
 133                 /* read the "stdin" and write that to the master
 134                  */
 135                 if (pfd[0].revents & POLLIN) {
 136                         read(0, &c, 1);
 137
 138                         /* we want to exit the console with Ctrl+a q */
 139                         if (c == 1) {
 140                                 wait4q = !wait4q;
 141                                 continue;
 142                         }
 143
 144                         if (c == 'q' && wait4q)
 145                                 goto out;
 146
 147                         wait4q = 0;
 148                         write(master, &c, 1);
 149                 }
 150
 151                 /* other side has closed the connection */
 152                 if (pfd[1].revents & POLLHUP)
 153                         goto out;
 154
 155                 /* read the master and write to "stdout" */
 156                 if (pfd[1].revents & POLLIN) {
 157                         read(master, &c, 1);
 158                         printf("%c", c);
 159                         fflush(stdout);
 160                 }
 161         }
 162 out:
 163         /* Restore previous terminal parameter */
 164         tcsetattr(0, TCSAFLUSH, &oldtios);
 165
 166         /* Return to line it is */
 167         printf("\n");
 168
 169         close(master);
 170
 171         return err;
 172
 173 out_err:
 174         fprintf(stderr, "%s\n", lxc_strerror(-LXC_ERROR_INTERNAL));
 175         err = 1;
 176         goto out;
 177 }