src/lxc/terminal.c

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2008
   5  *
   6  * Authors:
   7  * Daniel Lezcano <daniel.lezcano at free.fr>
   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #define _GNU_SOURCE
  25 #include <errno.h>
  26 #include <fcntl.h>
  27 #include <lxc/lxccontainer.h>
  28 #include <pthread.h>
  29 #include <signal.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <sys/epoll.h>
  33 #include <sys/types.h>
  34 #include <termios.h>
  35 #include <unistd.h>
  36
  37 #include "af_unix.h"
  38 #include "caps.h"
  39 #include "commands.h"
  40 #include "conf.h"
  41 #include "config.h"
  42 #include "log.h"
  43 #include "lxclock.h"
  44 #include "mainloop.h"
  45 #include "start.h"
  46 #include "terminal.h"
  47 #include "utils.h"
  48
  49 #if HAVE_PTY_H
  50 #include <pty.h>
  51 #else
  52 #include <../include/openpty.h>
  53 #endif
  54
  55 #define LXC_TERMINAL_BUFFER_SIZE 1024
  56
  57 lxc_log_define(terminal, lxc);
  58
  59 static struct lxc_list lxc_ttys;
  60
  61 typedef void (*sighandler_t)(int);
  62
  63 __attribute__((constructor)) void lxc_terminal_init_global(void)
  64 {
  65         lxc_list_init(&lxc_ttys);
  66 }
  67
  68 void lxc_terminal_winsz(int srcfd, int dstfd)
  69 {
  70         int ret;
  71         struct winsize wsz;
  72
  73         if (!isatty(srcfd))
  74                 return;
  75
  76         ret = ioctl(srcfd, TIOCGWINSZ, &wsz);
  77         if (ret < 0) {
  78                 WARN("Failed to get window size");
  79                 return;
  80         }
  81
  82         ret = ioctl(dstfd, TIOCSWINSZ, &wsz);
  83         if (ret < 0)
  84                 WARN("Failed to set window size");
  85         else
  86                 DEBUG("Set window size to %d columns and %d rows", wsz.ws_col,
  87                       wsz.ws_row);
  88
  89         return;
  90 }
  91
  92 static void lxc_terminal_winch(struct lxc_terminal_state *ts)
  93 {
  94         lxc_terminal_winsz(ts->stdinfd, ts->masterfd);
  95
  96         if (ts->winch_proxy)
  97                 lxc_cmd_terminal_winch(ts->winch_proxy, ts->winch_proxy_lxcpath);
  98 }
  99
 100 void lxc_terminal_sigwinch(int sig)
 101 {
 102         struct lxc_list *it;
 103         struct lxc_terminal_state *ts;
 104
 105         lxc_list_for_each(it, &lxc_ttys) {
 106                 ts = it->elem;
 107                 lxc_terminal_winch(ts);
 108         }
 109 }
 110
 111 int lxc_terminal_signalfd_cb(int fd, uint32_t events, void *cbdata,
 112                              struct lxc_epoll_descr *descr)
 113 {
 114         ssize_t ret;
 115         struct signalfd_siginfo siginfo;
 116         struct lxc_terminal_state *ts = cbdata;
 117
 118         ret = lxc_read_nointr(fd, &siginfo, sizeof(siginfo));
 119         if (ret < 0 || (size_t)ret < sizeof(siginfo)) {
 120                 ERROR("Failed to read signal info");
 121                 return LXC_MAINLOOP_ERROR;
 122         }
 123
 124         if (siginfo.ssi_signo == SIGTERM) {
 125                 DEBUG("Received SIGTERM. Detaching from the terminal");
 126                 return LXC_MAINLOOP_CLOSE;
 127         }
 128
 129         if (siginfo.ssi_signo == SIGWINCH)
 130                 lxc_terminal_winch(ts);
 131
 132         return LXC_MAINLOOP_CONTINUE;
 133 }
 134
 135 struct lxc_terminal_state *lxc_terminal_signal_init(int srcfd, int dstfd)
 136 {
 137         int ret;
 138         bool istty = false;
 139         sigset_t mask;
 140         struct lxc_terminal_state *ts;
 141
 142         ts = malloc(sizeof(*ts));
 143         if (!ts)
 144                 return NULL;
 145
 146         memset(ts, 0, sizeof(*ts));
 147         ts->stdinfd = srcfd;
 148         ts->masterfd = dstfd;
 149         ts->sigfd = -1;
 150
 151         ret = sigemptyset(&mask);
 152         if (ret < 0) {
 153                 SYSERROR("Failed to initialize an empty signal set");
 154                 goto on_error;
 155         }
 156
 157         istty = (isatty(srcfd) == 1);
 158         if (!istty) {
 159                 INFO("fd %d does not refer to a tty device", srcfd);
 160         } else {
 161                 /* Add tty to list to be scanned at SIGWINCH time. */
 162                 lxc_list_add_elem(&ts->node, ts);
 163                 lxc_list_add_tail(&lxc_ttys, &ts->node);
 164                 ret = sigaddset(&mask, SIGWINCH);
 165                 if (ret < 0)
 166                         SYSNOTICE("Failed to add SIGWINCH to signal set");
 167         }
 168
 169         /* Exit the mainloop cleanly on SIGTERM. */
 170         ret = sigaddset(&mask, SIGTERM);
 171         if (ret < 0) {
 172                 SYSERROR("Failed to add SIGWINCH to signal set");
 173                 goto on_error;
 174         }
 175
 176         ret = pthread_sigmask(SIG_BLOCK, &mask, &ts->oldmask);
 177         if (ret < 0) {
 178                 WARN("Failed to block signals");
 179                 goto on_error;
 180         }
 181
 182         ts->sigfd = signalfd(-1, &mask, SFD_CLOEXEC);
 183         if (ts->sigfd < 0) {
 184                 WARN("Failed to create signal fd");
 185                 (void)pthread_sigmask(SIG_SETMASK, &ts->oldmask, NULL);
 186                 goto on_error;
 187         }
 188
 189         DEBUG("Created signal fd %d", ts->sigfd);
 190         return ts;
 191
 192 on_error:
 193         ERROR("Failed to create signal fd");
 194         if (ts->sigfd >= 0) {
 195                 close(ts->sigfd);
 196                 ts->sigfd = -1;
 197         }
 198
 199         if (istty)
 200                 lxc_list_del(&ts->node);
 201
 202         return ts;
 203 }
 204
 205 void lxc_terminal_signal_fini(struct lxc_terminal_state *ts)
 206 {
 207         if (ts->sigfd >= 0) {
 208                 close(ts->sigfd);
 209
 210                 if (pthread_sigmask(SIG_SETMASK, &ts->oldmask, NULL) < 0)
 211                         SYSWARN("Failed to restore signal mask");
 212         }
 213
 214         if (isatty(ts->stdinfd))
 215                 lxc_list_del(&ts->node);
 216
 217         free(ts);
 218 }
 219
 220 static int lxc_terminal_truncate_log_file(struct lxc_terminal *terminal)
 221 {
 222         /* be very certain things are kosher */
 223         if (!terminal->log_path || terminal->log_fd < 0)
 224                 return -EBADF;
 225
 226         return lxc_unpriv(ftruncate(terminal->log_fd, 0));
 227 }
 228
 229 static int lxc_terminal_rotate_log_file(struct lxc_terminal *terminal)
 230 {
 231         int ret;
 232         size_t len;
 233         char *tmp;
 234
 235         if (!terminal->log_path || terminal->log_rotate == 0)
 236                 return -EOPNOTSUPP;
 237
 238         /* be very certain things are kosher */
 239         if (terminal->log_fd < 0)
 240                 return -EBADF;
 241
 242         len = strlen(terminal->log_path) + sizeof(".1");
 243         tmp = alloca(len);
 244
 245         ret = snprintf(tmp, len, "%s.1", terminal->log_path);
 246         if (ret < 0 || (size_t)ret >= len)
 247                 return -EFBIG;
 248
 249         close(terminal->log_fd);
 250         terminal->log_fd = -1;
 251         ret = lxc_unpriv(rename(terminal->log_path, tmp));
 252         if (ret < 0)
 253                 return ret;
 254
 255         return lxc_terminal_create_log_file(terminal);
 256 }
 257
 258 static int lxc_terminal_write_log_file(struct lxc_terminal *terminal, char *buf,
 259                                        int bytes_read)
 260 {
 261         int ret;
 262         struct stat st;
 263         int64_t space_left = -1;
 264
 265         if (terminal->log_fd < 0)
 266                 return 0;
 267
 268         /* A log size <= 0 means that there's no limit on the size of the log
 269          * file at which point we simply ignore whether the log is supposed to
 270          * be rotated or not.
 271          */
 272         if (terminal->log_size <= 0)
 273                 return lxc_write_nointr(terminal->log_fd, buf, bytes_read);
 274
 275         /* Get current size of the log file. */
 276         ret = fstat(terminal->log_fd, &st);
 277         if (ret < 0) {
 278                 SYSERROR("Failed to stat the terminal log file descriptor");
 279                 return -1;
 280         }
 281
 282         /* handle non-regular files */
 283         if ((st.st_mode & S_IFMT) != S_IFREG) {
 284                 /* This isn't a regular file. so rotating the file seems a
 285                  * dangerous thing to do, size limits are also very
 286                  * questionable. Let's not risk anything and tell the user that
 287                  * he's requesting us to do weird stuff.
 288                  */
 289                 if (terminal->log_rotate > 0 || terminal->log_size > 0)
 290                         return -EINVAL;
 291
 292                 /* I mean, sure log wherever you want to. */
 293                 return lxc_write_nointr(terminal->log_fd, buf, bytes_read);
 294         }
 295
 296         space_left = terminal->log_size - st.st_size;
 297
 298         /* User doesn't want to rotate the log file and there's no more space
 299          * left so simply truncate it.
 300          */
 301         if (space_left <= 0 && terminal->log_rotate <= 0) {
 302                 ret = lxc_terminal_truncate_log_file(terminal);
 303                 if (ret < 0)
 304                         return ret;
 305
 306                 if (bytes_read <= terminal->log_size)
 307                         return lxc_write_nointr(terminal->log_fd, buf, bytes_read);
 308
 309                 /* Write as much as we can into the buffer and loose the rest. */
 310                 return lxc_write_nointr(terminal->log_fd, buf, terminal->log_size);
 311         }
 312
 313         /* There's enough space left. */
 314         if (bytes_read <= space_left)
 315                 return lxc_write_nointr(terminal->log_fd, buf, bytes_read);
 316
 317         /* There's not enough space left but at least write as much as we can
 318          * into the old log file.
 319          */
 320         ret = lxc_write_nointr(terminal->log_fd, buf, space_left);
 321         if (ret < 0)
 322                 return -1;
 323
 324         /* Calculate how many bytes we still need to write. */
 325         bytes_read -= space_left;
 326
 327         /* There'd be more to write but we aren't instructed to rotate the log
 328          * file so simply return. There's no error on our side here.
 329          */
 330         if (terminal->log_rotate > 0)
 331                 ret = lxc_terminal_rotate_log_file(terminal);
 332         else
 333                 ret = lxc_terminal_truncate_log_file(terminal);
 334         if (ret < 0)
 335                 return ret;
 336
 337         if (terminal->log_size < bytes_read) {
 338                 /* Well, this is unfortunate because it means that there is more
 339                  * to write than the user has granted us space. There are
 340                  * multiple ways to handle this but let's use the simplest one:
 341                  * write as much as we can, tell the user that there was more
 342                  * stuff to write and move on.
 343                  * Note that this scenario shouldn't actually happen with the
 344                  * standard pty-based terminal that LXC allocates since it will
 345                  * be switched into raw mode. In raw mode only 1 byte at a time
 346                  * should be read and written.
 347                  */
 348                 WARN("Size of terminal log file is smaller than the bytes to write");
 349                 ret = lxc_write_nointr(terminal->log_fd, buf, terminal->log_size);
 350                 if (ret < 0)
 351                         return -1;
 352                 bytes_read -= ret;
 353                 return bytes_read;
 354         }
 355
 356         /* Yay, we made it. */
 357         ret = lxc_write_nointr(terminal->log_fd, buf, bytes_read);
 358         if (ret < 0)
 359                 return -1;
 360         bytes_read -= ret;
 361         return bytes_read;
 362 }
 363
 364 int lxc_terminal_io_cb(int fd, uint32_t events, void *data,
 365                        struct lxc_epoll_descr *descr)
 366 {
 367         struct lxc_terminal *terminal = data;
 368         char buf[LXC_TERMINAL_BUFFER_SIZE];
 369         int r, w, w_log, w_rbuf;
 370
 371         w = r = lxc_read_nointr(fd, buf, sizeof(buf));
 372         if (r <= 0) {
 373                 INFO("Terminal client on fd %d has exited", fd);
 374                 lxc_mainloop_del_handler(descr, fd);
 375
 376                 if (fd == terminal->master) {
 377                         terminal->master = -EBADF;
 378                 } else if (fd == terminal->peer) {
 379                         if (terminal->tty_state) {
 380                                 lxc_terminal_signal_fini(terminal->tty_state);
 381                                 terminal->tty_state = NULL;
 382                         }
 383                         terminal->peer = -EBADF;
 384                 } else {
 385                         ERROR("Handler received unexpected file descriptor");
 386                 }
 387                 close(fd);
 388
 389                 return LXC_MAINLOOP_CLOSE;
 390         }
 391
 392         if (fd == terminal->peer)
 393                 w = lxc_write_nointr(terminal->master, buf, r);
 394
 395         w_rbuf = w_log = 0;
 396         if (fd == terminal->master) {
 397                 /* write to peer first */
 398                 if (terminal->peer >= 0)
 399                         w = lxc_write_nointr(terminal->peer, buf, r);
 400
 401                 /* write to terminal ringbuffer */
 402                 if (terminal->buffer_size > 0)
 403                         w_rbuf = lxc_ringbuf_write(&terminal->ringbuf, buf, r);
 404
 405                 /* write to terminal log */
 406                 if (terminal->log_fd >= 0)
 407                         w_log = lxc_terminal_write_log_file(terminal, buf, r);
 408         }
 409
 410         if (w != r)
 411                 WARN("Short write on terminal r:%d != w:%d", r, w);
 412
 413         if (w_rbuf < 0) {
 414                 errno = -w_rbuf;
 415                 SYSTRACE("Failed to write %d bytes to terminal ringbuffer", r);
 416         }
 417
 418         if (w_log < 0)
 419                 TRACE("Failed to write %d bytes to terminal log", r);
 420
 421         return LXC_MAINLOOP_CONTINUE;
 422 }
 423
 424 static int lxc_terminal_mainloop_add_peer(struct lxc_terminal *terminal)
 425 {
 426         int ret;
 427
 428         if (terminal->peer >= 0) {
 429                 ret = lxc_mainloop_add_handler(terminal->descr, terminal->peer,
 430                                                lxc_terminal_io_cb, terminal);
 431                 if (ret < 0) {
 432                         WARN("Failed to add terminal peer handler to mainloop");
 433                         return -1;
 434                 }
 435         }
 436
 437         if (!terminal->tty_state || terminal->tty_state->sigfd < 0)
 438                 return 0;
 439
 440         ret = lxc_mainloop_add_handler(terminal->descr, terminal->tty_state->sigfd,
 441                                        lxc_terminal_signalfd_cb, terminal->tty_state);
 442         if (ret < 0) {
 443                 WARN("Failed to add signal handler to mainloop");
 444                 return -1;
 445         }
 446
 447         return 0;
 448 }
 449
 450 int lxc_terminal_mainloop_add(struct lxc_epoll_descr *descr,
 451                               struct lxc_terminal *terminal)
 452 {
 453         int ret;
 454
 455         if (terminal->master < 0) {
 456                 INFO("Terminal is not initialized");
 457                 return 0;
 458         }
 459
 460         ret = lxc_mainloop_add_handler(descr, terminal->master,
 461                                        lxc_terminal_io_cb, terminal);
 462         if (ret < 0) {
 463                 ERROR("Failed to add handler for terminal master fd %d to "
 464                       "mainloop", terminal->master);
 465                 return -1;
 466         }
 467
 468         /* We cache the descr so that we can add an fd to it when someone
 469          * does attach to it in lxc_terminal_allocate().
 470          */
 471         terminal->descr = descr;
 472
 473         return lxc_terminal_mainloop_add_peer(terminal);
 474 }
 475
 476 int lxc_setup_tios(int fd, struct termios *oldtios)
 477 {
 478         int ret;
 479         struct termios newtios;
 480
 481         if (!isatty(fd)) {
 482                 ERROR("File descriptor %d does not refert to a terminal", fd);
 483                 return -1;
 484         }
 485
 486         /* Get current termios. */
 487         ret = tcgetattr(fd, oldtios);
 488         if (ret < 0) {
 489                 SYSERROR("Failed to get current terminal settings");
 490                 return -1;
 491         }
 492
 493         /* ensure we don't end up in an endless loop:
 494          * The kernel might fire SIGTTOU while an
 495          * ioctl() in tcsetattr() is executed. When the ioctl()
 496          * is resumed and retries, the signal handler interrupts it again.
 497          */
 498         signal (SIGTTIN, SIG_IGN);
 499         signal (SIGTTOU, SIG_IGN);
 500
 501         newtios = *oldtios;
 502
 503         /* We use the same settings that ssh does. */
 504         newtios.c_iflag |= IGNPAR;
 505         newtios.c_iflag &= ~(ISTRIP | INLCR | IGNCR | ICRNL | IXON | IXANY | IXOFF);
 506 #ifdef IUCLC
 507         newtios.c_iflag &= ~IUCLC;
 508 #endif
 509         newtios.c_lflag &= ~(TOSTOP | ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHONL);
 510 #ifdef IEXTEN
 511         newtios.c_lflag &= ~IEXTEN;
 512 #endif
 513         newtios.c_oflag &= ~ONLCR;
 514         newtios.c_oflag |= OPOST;
 515         newtios.c_cc[VMIN] = 1;
 516         newtios.c_cc[VTIME] = 0;
 517
 518         /* Set new attributes. */
 519         ret = tcsetattr(fd, TCSAFLUSH, &newtios);
 520         if (ret < 0) {
 521                 ERROR("Failed to set new terminal settings");
 522                 return -1;
 523         }
 524
 525         return 0;
 526 }
 527
 528 static void lxc_terminal_peer_proxy_free(struct lxc_terminal *terminal)
 529 {
 530         if (terminal->tty_state) {
 531                 lxc_terminal_signal_fini(terminal->tty_state);
 532                 terminal->tty_state = NULL;
 533         }
 534
 535         close(terminal->proxy.master);
 536         terminal->proxy.master = -1;
 537
 538         close(terminal->proxy.slave);
 539         terminal->proxy.slave = -1;
 540
 541         terminal->proxy.busy = -1;
 542
 543         terminal->proxy.name[0] = '\0';
 544
 545         terminal->peer = -1;
 546 }
 547
 548 static int lxc_terminal_peer_proxy_alloc(struct lxc_terminal *terminal,
 549                                          int sockfd)
 550 {
 551         int ret;
 552         struct termios oldtermio;
 553         struct lxc_terminal_state *ts;
 554
 555         if (terminal->master < 0) {
 556                 ERROR("Terminal not set up");
 557                 return -1;
 558         }
 559
 560         if (terminal->proxy.busy != -1 || terminal->peer != -1) {
 561                 NOTICE("Terminal already in use");
 562                 return -1;
 563         }
 564
 565         if (terminal->tty_state) {
 566                 ERROR("Terminal has already been initialized");
 567                 return -1;
 568         }
 569
 570         /* This is the proxy terminal that will be given to the client, and
 571          * that the real terminal master will send to / recv from.
 572          */
 573         ret = openpty(&terminal->proxy.master, &terminal->proxy.slave, NULL,
 574                       NULL, NULL);
 575         if (ret < 0) {
 576                 SYSERROR("Failed to open proxy terminal");
 577                 return -1;
 578         }
 579
 580         ret = ttyname_r(terminal->proxy.slave, terminal->proxy.name,
 581                         sizeof(terminal->proxy.name));
 582         if (ret < 0) {
 583                 SYSERROR("Failed to retrieve name of proxy terminal slave");
 584                 goto on_error;
 585         }
 586
 587         ret = fd_cloexec(terminal->proxy.master, true);
 588         if (ret < 0) {
 589                 SYSERROR("Failed to set FD_CLOEXEC flag on proxy terminal master");
 590                 goto on_error;
 591         }
 592
 593         ret = fd_cloexec(terminal->proxy.slave, true);
 594         if (ret < 0) {
 595                 SYSERROR("Failed to set FD_CLOEXEC flag on proxy terminal slave");
 596                 goto on_error;
 597         }
 598
 599         ret = lxc_setup_tios(terminal->proxy.slave, &oldtermio);
 600         if (ret < 0)
 601                 goto on_error;
 602
 603         ts = lxc_terminal_signal_init(terminal->proxy.master, terminal->master);
 604         if (!ts)
 605                 goto on_error;
 606
 607         terminal->tty_state = ts;
 608         terminal->peer = terminal->proxy.slave;
 609         terminal->proxy.busy = sockfd;
 610         ret = lxc_terminal_mainloop_add_peer(terminal);
 611         if (ret < 0)
 612                 goto on_error;
 613
 614         NOTICE("Opened proxy terminal with master fd %d and slave fd %d",
 615                terminal->proxy.master, terminal->proxy.slave);
 616         return 0;
 617
 618 on_error:
 619         lxc_terminal_peer_proxy_free(terminal);
 620         return -1;
 621 }
 622
 623 int lxc_terminal_allocate(struct lxc_conf *conf, int sockfd, int *ttyreq)
 624 {
 625         int ttynum;
 626         int masterfd = -1;
 627         struct lxc_tty_info *ttys = &conf->ttys;
 628         struct lxc_terminal *terminal = &conf->console;
 629
 630         if (*ttyreq == 0) {
 631                 int ret;
 632
 633                 ret = lxc_terminal_peer_proxy_alloc(terminal, sockfd);
 634                 if (ret < 0)
 635                         goto out;
 636
 637                 masterfd = terminal->proxy.master;
 638                 goto out;
 639         }
 640
 641         if (*ttyreq > 0) {
 642                 if (*ttyreq > ttys->max)
 643                         goto out;
 644
 645                 if (ttys->tty[*ttyreq - 1].busy)
 646                         goto out;
 647
 648                 /* The requested tty is available. */
 649                 ttynum = *ttyreq;
 650                 goto out_tty;
 651         }
 652
 653         /* Search for next available tty, fixup index tty1 => [0]. */
 654         for (ttynum = 1; ttynum <= ttys->max && ttys->tty[ttynum - 1].busy; ttynum++) {
 655                 ;
 656         }
 657
 658         /* We didn't find any available slot for tty. */
 659         if (ttynum > ttys->max)
 660                 goto out;
 661
 662         *ttyreq = ttynum;
 663
 664 out_tty:
 665         ttys->tty[ttynum - 1].busy = sockfd;
 666         masterfd = ttys->tty[ttynum - 1].master;
 667
 668 out:
 669         return masterfd;
 670 }
 671
 672 void lxc_terminal_free(struct lxc_conf *conf, int fd)
 673 {
 674         int i;
 675         struct lxc_tty_info *ttys = &conf->ttys;
 676         struct lxc_terminal *terminal = &conf->console;
 677
 678         for (i = 0; i < ttys->max; i++)
 679                 if (ttys->tty[i].busy == fd)
 680                         ttys->tty[i].busy = 0;
 681
 682         if (terminal->proxy.busy != fd)
 683                 return;
 684
 685         lxc_mainloop_del_handler(terminal->descr, terminal->proxy.slave);
 686         lxc_terminal_peer_proxy_free(terminal);
 687 }
 688
 689 static int lxc_terminal_peer_default(struct lxc_terminal *terminal)
 690 {
 691         struct lxc_terminal_state *ts;
 692         const char *path;
 693         int ret = 0;
 694
 695         if (terminal->path)
 696                 path = terminal->path;
 697         else
 698                 path = "/dev/tty";
 699
 700         terminal->peer = lxc_unpriv(open(path, O_RDWR | O_CLOEXEC));
 701         if (terminal->peer < 0) {
 702                 if (!terminal->path) {
 703                         errno = ENODEV;
 704                         SYSDEBUG("The process does not have a controlling terminal");
 705                         goto on_succes;
 706                 }
 707
 708                 SYSERROR("Failed to open proxy terminal \"%s\"", path);
 709                 return -ENOTTY;
 710         }
 711         DEBUG("Using terminal \"%s\" as proxy", path);
 712
 713         if (!isatty(terminal->peer)) {
 714                 ERROR("File descriptor for \"%s\" does not refer to a terminal", path);
 715                 goto on_error_free_tios;
 716         }
 717
 718         ts = lxc_terminal_signal_init(terminal->peer, terminal->master);
 719         terminal->tty_state = ts;
 720         if (!ts) {
 721                 WARN("Failed to install signal handler");
 722                 goto on_error_free_tios;
 723         }
 724
 725         lxc_terminal_winsz(terminal->peer, terminal->master);
 726
 727         terminal->tios = malloc(sizeof(*terminal->tios));
 728         if (!terminal->tios)
 729                 goto on_error_free_tios;
 730
 731         ret = lxc_setup_tios(terminal->peer, terminal->tios);
 732         if (ret < 0)
 733                 goto on_error_close_peer;
 734         else
 735                 goto on_succes;
 736
 737 on_error_free_tios:
 738         free(terminal->tios);
 739         terminal->tios = NULL;
 740
 741 on_error_close_peer:
 742         close(terminal->peer);
 743         terminal->peer = -1;
 744         ret = -ENOTTY;
 745
 746 on_succes:
 747         return ret;
 748 }
 749
 750 int lxc_terminal_write_ringbuffer(struct lxc_terminal *terminal)
 751 {
 752         char *r_addr;
 753         ssize_t ret;
 754         uint64_t used;
 755         struct lxc_ringbuf *buf = &terminal->ringbuf;
 756
 757         /* There's not log file where we can dump the ringbuffer to. */
 758         if (terminal->log_fd < 0)
 759                 return 0;
 760
 761         used = lxc_ringbuf_used(buf);
 762         if (used == 0)
 763                 return 0;
 764
 765         ret = lxc_terminal_truncate_log_file(terminal);
 766         if (ret < 0)
 767                 return ret;
 768
 769         /* Write as much as we can without exceeding the limit. */
 770         if (terminal->log_size < used)
 771                 used = terminal->log_size;
 772
 773         r_addr = lxc_ringbuf_get_read_addr(buf);
 774         ret = lxc_write_nointr(terminal->log_fd, r_addr, used);
 775         if (ret < 0)
 776                 return -EIO;
 777
 778         return 0;
 779 }
 780
 781 void lxc_terminal_delete(struct lxc_terminal *terminal)
 782 {
 783         int ret;
 784
 785         ret = lxc_terminal_write_ringbuffer(terminal);
 786         if (ret < 0)
 787                 WARN("Failed to write terminal log to disk");
 788
 789         if (terminal->tios && terminal->peer >= 0) {
 790                 ret = tcsetattr(terminal->peer, TCSAFLUSH, terminal->tios);
 791                 if (ret < 0)
 792                         SYSWARN("Failed to set old terminal settings");
 793         }
 794         free(terminal->tios);
 795         terminal->tios = NULL;
 796
 797         if (terminal->peer >= 0)
 798                 close(terminal->peer);
 799         terminal->peer = -1;
 800
 801         if (terminal->master >= 0)
 802                 close(terminal->master);
 803         terminal->master = -1;
 804
 805         if (terminal->slave >= 0)
 806                 close(terminal->slave);
 807         terminal->slave = -1;
 808
 809         if (terminal->log_fd >= 0)
 810                 close(terminal->log_fd);
 811         terminal->log_fd = -1;
 812 }
 813
 814 /**
 815  * Note that this function needs to run before the mainloop starts. Since we
 816  * register a handler for the terminal's masterfd when we create the mainloop
 817  * the terminal handler needs to see an allocated ringbuffer.
 818  */
 819 static int lxc_terminal_create_ringbuf(struct lxc_terminal *terminal)
 820 {
 821         int ret;
 822         struct lxc_ringbuf *buf = &terminal->ringbuf;
 823         uint64_t size = terminal->buffer_size;
 824
 825         /* no ringbuffer previously allocated and no ringbuffer requested */
 826         if (!buf->addr && size <= 0)
 827                 return 0;
 828
 829         /* ringbuffer allocated but no new ringbuffer requested */
 830         if (buf->addr && size <= 0) {
 831                 lxc_ringbuf_release(buf);
 832                 buf->addr = NULL;
 833                 buf->r_off = 0;
 834                 buf->w_off = 0;
 835                 buf->size = 0;
 836                 TRACE("Deallocated terminal ringbuffer");
 837                 return 0;
 838         }
 839
 840         if (size <= 0)
 841                 return 0;
 842
 843         /* check wether the requested size for the ringbuffer has changed */
 844         if (buf->addr && buf->size != size) {
 845                 TRACE("Terminal ringbuffer size changed from %" PRIu64
 846                       " to %" PRIu64 " bytes. Deallocating terminal ringbuffer",
 847                       buf->size, size);
 848                 lxc_ringbuf_release(buf);
 849         }
 850
 851         ret = lxc_ringbuf_create(buf, size);
 852         if (ret < 0) {
 853                 ERROR("Failed to setup %" PRIu64 " byte terminal ringbuffer", size);
 854                 return -1;
 855         }
 856
 857         TRACE("Allocated %" PRIu64 " byte terminal ringbuffer", size);
 858         return 0;
 859 }
 860
 861 /**
 862  * This is the terminal log file. Please note that the terminal log file is
 863  * (implementation wise not content wise) independent of the terminal ringbuffer.
 864  */
 865 int lxc_terminal_create_log_file(struct lxc_terminal *terminal)
 866 {
 867         if (!terminal->log_path)
 868                 return 0;
 869
 870         terminal->log_fd = lxc_unpriv(open(terminal->log_path, O_CLOEXEC | O_RDWR | O_CREAT | O_APPEND, 0600));
 871         if (terminal->log_fd < 0) {
 872                 SYSERROR("Failed to open terminal log file \"%s\"", terminal->log_path);
 873                 return -1;
 874         }
 875
 876         DEBUG("Using \"%s\" as terminal log file", terminal->log_path);
 877         return 0;
 878 }
 879
 880 int lxc_terminal_create(struct lxc_terminal *terminal)
 881 {
 882         int ret;
 883
 884         ret = openpty(&terminal->master, &terminal->slave, NULL, NULL, NULL);
 885         if (ret < 0) {
 886                 SYSERROR("Failed to open terminal");
 887                 return -1;
 888         }
 889
 890         ret = ttyname_r(terminal->slave, terminal->name, sizeof(terminal->name));
 891         if (ret < 0) {
 892                 SYSERROR("Failed to retrieve name of terminal slave");
 893                 goto err;
 894         }
 895
 896         ret = fd_cloexec(terminal->master, true);
 897         if (ret < 0) {
 898                 SYSERROR("Failed to set FD_CLOEXEC flag on terminal master");
 899                 goto err;
 900         }
 901
 902         ret = fd_cloexec(terminal->slave, true);
 903         if (ret < 0) {
 904                 SYSERROR("Failed to set FD_CLOEXEC flag on terminal slave");
 905                 goto err;
 906         }
 907
 908         ret = lxc_terminal_peer_default(terminal);
 909         if (ret < 0) {
 910                 ERROR("Failed to allocate proxy terminal");
 911                 goto err;
 912         }
 913
 914         return 0;
 915
 916 err:
 917         lxc_terminal_delete(terminal);
 918         return -ENODEV;
 919 }
 920
 921 int lxc_terminal_setup(struct lxc_conf *conf)
 922 {
 923         int ret;
 924         struct lxc_terminal *terminal = &conf->console;
 925
 926         if (terminal->path && strcmp(terminal->path, "none") == 0) {
 927                 INFO("No terminal requested");
 928                 return 0;
 929         }
 930
 931         ret = lxc_terminal_create(terminal);
 932         if (ret < 0)
 933                 return -1;
 934
 935         ret = lxc_terminal_create_log_file(terminal);
 936         if (ret < 0)
 937                 goto err;
 938
 939         ret = lxc_terminal_create_ringbuf(terminal);
 940         if (ret < 0)
 941                 goto err;
 942
 943         return 0;
 944
 945 err:
 946         lxc_terminal_delete(terminal);
 947         return -ENODEV;
 948 }
 949
 950 static bool __terminal_dup2(int duplicate, int original)
 951 {
 952         int ret;
 953
 954         if (!isatty(original))
 955                 return true;
 956
 957         ret = dup2(duplicate, original);
 958         if (ret < 0) {
 959                 SYSERROR("Failed to dup2(%d, %d)", duplicate, original);
 960                 return false;
 961         }
 962
 963         return true;
 964 }
 965
 966 int lxc_terminal_set_stdfds(int fd)
 967 {
 968         int i;
 969
 970         if (fd < 0)
 971                 return 0;
 972
 973         for (i = 0; i < 3; i++)
 974                 if (!__terminal_dup2(fd, (int[]){STDIN_FILENO, STDOUT_FILENO,
 975                                                  STDERR_FILENO}[i]))
 976                         return -1;
 977
 978         return 0;
 979 }
 980
 981 int lxc_terminal_stdin_cb(int fd, uint32_t events, void *cbdata,
 982                           struct lxc_epoll_descr *descr)
 983 {
 984         int ret;
 985         char c;
 986         struct lxc_terminal_state *ts = cbdata;
 987
 988         if (fd != ts->stdinfd)
 989                 return LXC_MAINLOOP_CLOSE;
 990
 991         ret = lxc_read_nointr(ts->stdinfd, &c, 1);
 992         if (ret <= 0)
 993                 return LXC_MAINLOOP_CLOSE;
 994
 995         if (ts->escape >= 1) {
 996                 /* we want to exit the terminal with Ctrl+a q */
 997                 if (c == ts->escape && !ts->saw_escape) {
 998                         ts->saw_escape = 1;
 999                         return LXC_MAINLOOP_CONTINUE;
1000                 }
1001
1002                 if (c == 'q' && ts->saw_escape)
1003                         return LXC_MAINLOOP_CLOSE;
1004
1005                 ts->saw_escape = 0;
1006         }
1007
1008         ret = lxc_write_nointr(ts->masterfd, &c, 1);
1009         if (ret <= 0)
1010                 return LXC_MAINLOOP_CLOSE;
1011
1012         return LXC_MAINLOOP_CONTINUE;
1013 }
1014
1015 int lxc_terminal_master_cb(int fd, uint32_t events, void *cbdata,
1016                            struct lxc_epoll_descr *descr)
1017 {
1018         int r, w;
1019         char buf[LXC_TERMINAL_BUFFER_SIZE];
1020         struct lxc_terminal_state *ts = cbdata;
1021
1022         if (fd != ts->masterfd)
1023                 return LXC_MAINLOOP_CLOSE;
1024
1025         r = lxc_read_nointr(fd, buf, sizeof(buf));
1026         if (r <= 0)
1027                 return LXC_MAINLOOP_CLOSE;
1028
1029         w = lxc_write_nointr(ts->stdoutfd, buf, r);
1030         if (w <= 0 || w != r)
1031                 return LXC_MAINLOOP_CLOSE;
1032
1033         return LXC_MAINLOOP_CONTINUE;
1034 }
1035
1036 int lxc_terminal_getfd(struct lxc_container *c, int *ttynum, int *masterfd)
1037 {
1038         return lxc_cmd_console(c->name, ttynum, masterfd, c->config_path);
1039 }
1040
1041 int lxc_console(struct lxc_container *c, int ttynum,
1042                 int stdinfd, int stdoutfd, int stderrfd,
1043                 int escape)
1044 {
1045         int masterfd, ret, ttyfd;
1046         struct lxc_epoll_descr descr;
1047         struct termios oldtios;
1048         struct lxc_terminal_state *ts;
1049         int istty = 0;
1050
1051         ttyfd = lxc_cmd_console(c->name, &ttynum, &masterfd, c->config_path);
1052         if (ttyfd < 0)
1053                 return -1;
1054
1055         ret = setsid();
1056         if (ret < 0)
1057                 TRACE("Process is already group leader");
1058
1059         ts = lxc_terminal_signal_init(stdinfd, masterfd);
1060         if (!ts) {
1061                 ret = -1;
1062                 goto close_fds;
1063         }
1064         ts->escape = escape;
1065         ts->winch_proxy = c->name;
1066         ts->winch_proxy_lxcpath = c->config_path;
1067         ts->stdoutfd = stdoutfd;
1068
1069         istty = isatty(stdinfd);
1070         if (istty) {
1071                 lxc_terminal_winsz(stdinfd, masterfd);
1072                 lxc_cmd_terminal_winch(ts->winch_proxy, ts->winch_proxy_lxcpath);
1073         } else {
1074                 INFO("File descriptor %d does not refer to a terminal", stdinfd);
1075         }
1076
1077         ret = lxc_mainloop_open(&descr);
1078         if (ret) {
1079                 ERROR("Failed to create mainloop");
1080                 goto sigwinch_fini;
1081         }
1082
1083         if (ts->sigfd != -1) {
1084                 ret = lxc_mainloop_add_handler(&descr, ts->sigfd,
1085                                                lxc_terminal_signalfd_cb, ts);
1086                 if (ret < 0) {
1087                         ERROR("Failed to add signal handler to mainloop");
1088                         goto close_mainloop;
1089                 }
1090         }
1091
1092         ret = lxc_mainloop_add_handler(&descr, ts->stdinfd,
1093                                        lxc_terminal_stdin_cb, ts);
1094         if (ret < 0) {
1095                 ERROR("Failed to add stdin handler");
1096                 goto close_mainloop;
1097         }
1098
1099         ret = lxc_mainloop_add_handler(&descr, ts->masterfd,
1100                                        lxc_terminal_master_cb, ts);
1101         if (ret < 0) {
1102                 ERROR("Failed to add master handler");
1103                 goto close_mainloop;
1104         }
1105
1106         if (ts->escape >= 1) {
1107                 fprintf(stderr,
1108                         "\n"
1109                         "Connected to tty %1$d\n"
1110                         "Type <Ctrl+%2$c q> to exit the console, "
1111                         "<Ctrl+%2$c Ctrl+%2$c> to enter Ctrl+%2$c itself\n",
1112                         ttynum, 'a' + escape - 1);
1113         }
1114
1115         if (istty) {
1116                 ret = lxc_setup_tios(stdinfd, &oldtios);
1117                 if (ret < 0)
1118                         goto close_mainloop;
1119         }
1120
1121         ret = lxc_mainloop(&descr, -1);
1122         if (ret < 0) {
1123                 ERROR("The mainloop returned an error");
1124                 goto restore_tios;
1125         }
1126
1127         ret = 0;
1128
1129 restore_tios:
1130         if (istty) {
1131                 istty = tcsetattr(stdinfd, TCSAFLUSH, &oldtios);
1132                 if (istty < 0)
1133                         SYSWARN("Failed to restore terminal properties");
1134         }
1135
1136 close_mainloop:
1137         lxc_mainloop_close(&descr);
1138
1139 sigwinch_fini:
1140         lxc_terminal_signal_fini(ts);
1141
1142 close_fds:
1143         close(masterfd);
1144         close(ttyfd);
1145
1146         return ret;
1147 }
1148
1149 int lxc_make_controlling_terminal(int fd)
1150 {
1151         int ret;
1152
1153         setsid();
1154
1155         ret = ioctl(fd, TIOCSCTTY, (char *)NULL);
1156         if (ret < 0)
1157                 return -1;
1158
1159         return 0;
1160 }
1161
1162 int lxc_terminal_prepare_login(int fd)
1163 {
1164         int ret;
1165
1166         ret = lxc_make_controlling_terminal(fd);
1167         if (ret < 0)
1168                 return -1;
1169
1170         ret = lxc_terminal_set_stdfds(fd);
1171         if (ret < 0)
1172                 return -1;
1173
1174         if (fd > STDERR_FILENO)
1175                 close(fd);
1176
1177         return 0;
1178 }
1179
1180 void lxc_terminal_info_init(struct lxc_terminal_info *terminal)
1181 {
1182         terminal->name[0] = '\0';
1183         terminal->master = -EBADF;
1184         terminal->slave = -EBADF;
1185         terminal->busy = -1;
1186 }
1187
1188 void lxc_terminal_init(struct lxc_terminal *terminal)
1189 {
1190         memset(terminal, 0, sizeof(*terminal));
1191         terminal->slave = -EBADF;
1192         terminal->master = -EBADF;
1193         terminal->peer = -EBADF;
1194         terminal->log_fd = -EBADF;
1195         lxc_terminal_info_init(&terminal->proxy);
1196 }
1197
1198 void lxc_terminal_conf_free(struct lxc_terminal *terminal)
1199 {
1200         free(terminal->log_path);
1201         free(terminal->path);
1202         if (terminal->buffer_size > 0 && terminal->ringbuf.addr)
1203                 lxc_ringbuf_release(&terminal->ringbuf);
1204 }
1205
1206 int lxc_terminal_map_ids(struct lxc_conf *c, struct lxc_terminal *terminal)
1207 {
1208         int ret;
1209
1210         if (lxc_list_empty(&c->id_map))
1211                 return 0;
1212
1213         if (strcmp(terminal->name, "") == 0)
1214                 return 0;
1215
1216         ret = chown_mapped_root(terminal->name, c);
1217         if (ret < 0) {
1218                 ERROR("Failed to chown terminal \"%s\"", terminal->name);
1219                 return -1;
1220         }
1221
1222         TRACE("Chowned terminal \"%s\"", terminal->name);
1223
1224         return 0;
1225 }