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 #include <sys/ioctl.h>
  40
  41 #include "error.h"
  42 #include "lxc.h"
  43 #include "log.h"
  44 #include "mainloop.h"
  45 #include "arguments.h"
  46
  47 lxc_log_define(lxc_console_ui, lxc_console);
  48
  49 static char etoc(const char *expr)
  50 {
  51         /* returns "control code" of given expression */
  52         char c = expr[0] == '^' ? expr[1] : expr[0];
  53         return 1 + ((c > 'Z') ? (c - 'a') : (c - 'Z'));
  54 }
  55
  56 static int my_parser(struct lxc_arguments* args, int c, char* arg)
  57 {
  58         switch (c) {
  59         case 't': args->ttynum = atoi(arg); break;
  60         case 'e': args->escape = etoc(arg); break;
  61         }
  62         return 0;
  63 }
  64
  65 static const struct option my_longopts[] = {
  66         {"tty", required_argument, 0, 't'},
  67         {"escape", required_argument, 0, 'e'},
  68         LXC_COMMON_OPTIONS
  69 };
  70
  71 static struct lxc_arguments my_args = {
  72         .progname = "lxc-console",
  73         .help     = "\
  74 --name=NAME [--tty NUMBER]\n\
  75 \n\
  76 lxc-console logs on the container with the identifier NAME\n\
  77 \n\
  78 Options :\n\
  79   -n, --name=NAME      NAME for name of the container\n\
  80   -t, --tty=NUMBER     console tty number\n\
  81   -e, --escape=PREFIX  prefix for escape command\n",
  82         .options  = my_longopts,
  83         .parser   = my_parser,
  84         .checker  = NULL,
  85         .ttynum = -1,
  86         .escape = 1,
  87 };
  88
  89 static int master = -1;
  90
  91 static void winsz(void)
  92 {
  93         struct winsize wsz;
  94         if (ioctl(0, TIOCGWINSZ, &wsz) == 0)
  95                 ioctl(master, TIOCSWINSZ, &wsz);
  96 }
  97
  98 static void sigwinch(int sig)
  99 {
 100         winsz();
 101 }
 102
 103 static int setup_tios(int fd, struct termios *newtios, struct termios *oldtios)
 104 {
 105         if (!isatty(fd)) {
 106                 ERROR("'%d' is not a tty", fd);
 107                 return -1;
 108         }
 109
 110         /* Get current termios */
 111         if (tcgetattr(0, oldtios)) {
 112                 SYSERROR("failed to get current terminal settings");
 113                 return -1;
 114         }
 115
 116         *newtios = *oldtios;
 117
 118         /* Remove the echo characters and signal reception, the echo
 119          * will be done below with master proxying */
 120         newtios->c_iflag &= ~IGNBRK;
 121         newtios->c_iflag &= BRKINT;
 122         newtios->c_lflag &= ~(ECHO|ICANON|ISIG);
 123         newtios->c_cc[VMIN] = 1;
 124         newtios->c_cc[VTIME] = 0;
 125
 126         /* Set new attributes */
 127         if (tcsetattr(0, TCSAFLUSH, newtios)) {
 128                 ERROR("failed to set new terminal settings");
 129                 return -1;
 130         }
 131
 132         return 0;
 133 }
 134
 135 static int stdin_handler(int fd, void *data, struct lxc_epoll_descr *descr)
 136 {
 137         static int wait4q = 0;
 138         int *peer = (int *)data;
 139         char c;
 140
 141         if (read(0, &c, 1) < 0) {
 142                 SYSERROR("failed to read");
 143                 return 1;
 144         }
 145
 146         /* we want to exit the console with Ctrl+a q */
 147         if (c == my_args.escape && !wait4q) {
 148                 wait4q = !wait4q;
 149                 return 0;
 150         }
 151
 152         if (c == 'q' && wait4q)
 153                 return 1;
 154
 155         wait4q = 0;
 156         if (write(*peer, &c, 1) < 0) {
 157                 SYSERROR("failed to write");
 158                 return 1;
 159         }
 160
 161         return 0;
 162 }
 163
 164 static int master_handler(int fd, void *data, struct lxc_epoll_descr *descr)
 165 {
 166         char buf[1024];
 167         int *peer = (int *)data;
 168         int r;
 169
 170         r = read(fd, buf, sizeof(buf));
 171         if (r < 0) {
 172                 SYSERROR("failed to read");
 173                 return 1;
 174         }
 175         r = write(*peer, buf, r);
 176
 177         return 0;
 178 }
 179
 180 int main(int argc, char *argv[])
 181 {
 182         int err, std_in = 1;
 183         struct lxc_epoll_descr descr;
 184         struct termios newtios, oldtios;
 185
 186         err = lxc_arguments_parse(&my_args, argc, argv);
 187         if (err)
 188                 return -1;
 189
 190         err = lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
 191                            my_args.progname, my_args.quiet);
 192         if (err)
 193                 return -1;
 194
 195         err = setup_tios(0, &newtios, &oldtios);
 196         if (err) {
 197                 ERROR("failed to setup tios");
 198                 return -1;
 199         }
 200
 201         err = lxc_console(my_args.name, my_args.ttynum, &master);
 202         if (err)
 203                 goto out;
 204
 205         fprintf(stderr, "\n\
 206 Type <Ctrl+%1$c q> to exit the console, \
 207 <Ctrl+%1$c Ctrl+%1$c> to enter Ctrl+%1$c itself\n",
 208                 'a' + my_args.escape - 1);
 209
 210         err = setsid();
 211         if (err)
 212                 INFO("already group leader");
 213
 214         if (signal(SIGWINCH, sigwinch) == SIG_ERR) {
 215                 SYSERROR("failed to set SIGWINCH handler");
 216                 err = -1;
 217                 goto out;
 218         }
 219
 220         winsz();
 221
 222         err = lxc_mainloop_open(&descr);
 223         if (err) {
 224                 ERROR("failed to create mainloop");
 225                 goto out;
 226         }
 227
 228         err = lxc_mainloop_add_handler(&descr, 0, stdin_handler, &master);
 229         if (err) {
 230                 ERROR("failed to add handler for the stdin");
 231                 goto out_mainloop_open;
 232         }
 233
 234         err = lxc_mainloop_add_handler(&descr, master, master_handler, &std_in);
 235         if (err) {
 236                 ERROR("failed to add handler for the master");
 237                 goto out_mainloop_open;
 238         }
 239
 240         err = lxc_mainloop(&descr);
 241         if (err) {
 242                 ERROR("mainloop returned an error");
 243                 goto out_mainloop_open;
 244         }
 245
 246         err =  0;
 247
 248 out_mainloop_open:
 249         lxc_mainloop_close(&descr);
 250
 251 out:
 252         /* Restore previous terminal parameter */
 253         tcsetattr(0, TCSAFLUSH, &oldtios);
 254
 255         /* Return to line it is */
 256         printf("\n");
 257
 258         close(master);
 259
 260         return err;
 261 }