src/basic/terminal-util.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <assert.h>
  21 #include <fcntl.h>
  22 #include <linux/kd.h>
  23 #include <linux/tiocl.h>
  24 #include <linux/vt.h>
  25 #include <poll.h>
  26 #include <signal.h>
  27 #include <sys/ioctl.h>
  28 #include <sys/stat.h>
  29 #include <sys/types.h>
  30 #include <termios.h>
  31 #include <time.h>
  32 #include <unistd.h>
  33
  34 #include "fileio.h"
  35 #include "path-util.h"
  36 #include "process-util.h"
  37 #include "string-util.h"
  38 #include "time-util.h"
  39 #include "util.h"
  40 #include "terminal-util.h"
  41
  42 static volatile unsigned cached_columns = 0;
  43 static volatile unsigned cached_lines = 0;
  44
  45 int chvt(int vt) {
  46         _cleanup_close_ int fd;
  47
  48         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
  49         if (fd < 0)
  50                 return -errno;
  51
  52         if (vt <= 0) {
  53                 int tiocl[2] = {
  54                         TIOCL_GETKMSGREDIRECT,
  55                         0
  56                 };
  57
  58                 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
  59                         return -errno;
  60
  61                 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
  62         }
  63
  64         if (ioctl(fd, VT_ACTIVATE, vt) < 0)
  65                 return -errno;
  66
  67         return 0;
  68 }
  69
  70 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
  71         struct termios old_termios, new_termios;
  72         char c, line[LINE_MAX];
  73
  74         assert(f);
  75         assert(ret);
  76
  77         if (tcgetattr(fileno(f), &old_termios) >= 0) {
  78                 new_termios = old_termios;
  79
  80                 new_termios.c_lflag &= ~ICANON;
  81                 new_termios.c_cc[VMIN] = 1;
  82                 new_termios.c_cc[VTIME] = 0;
  83
  84                 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
  85                         size_t k;
  86
  87                         if (t != USEC_INFINITY) {
  88                                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
  89                                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
  90                                         return -ETIMEDOUT;
  91                                 }
  92                         }
  93
  94                         k = fread(&c, 1, 1, f);
  95
  96                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
  97
  98                         if (k <= 0)
  99                                 return -EIO;
 100
 101                         if (need_nl)
 102                                 *need_nl = c != '\n';
 103
 104                         *ret = c;
 105                         return 0;
 106                 }
 107         }
 108
 109         if (t != USEC_INFINITY) {
 110                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
 111                         return -ETIMEDOUT;
 112         }
 113
 114         errno = 0;
 115         if (!fgets(line, sizeof(line), f))
 116                 return errno ? -errno : -EIO;
 117
 118         truncate_nl(line);
 119
 120         if (strlen(line) != 1)
 121                 return -EBADMSG;
 122
 123         if (need_nl)
 124                 *need_nl = false;
 125
 126         *ret = line[0];
 127         return 0;
 128 }
 129
 130 int ask_char(char *ret, const char *replies, const char *text, ...) {
 131         int r;
 132
 133         assert(ret);
 134         assert(replies);
 135         assert(text);
 136
 137         for (;;) {
 138                 va_list ap;
 139                 char c;
 140                 bool need_nl = true;
 141
 142                 if (on_tty())
 143                         fputs(ANSI_HIGHLIGHT, stdout);
 144
 145                 va_start(ap, text);
 146                 vprintf(text, ap);
 147                 va_end(ap);
 148
 149                 if (on_tty())
 150                         fputs(ANSI_NORMAL, stdout);
 151
 152                 fflush(stdout);
 153
 154                 r = read_one_char(stdin, &c, USEC_INFINITY, &need_nl);
 155                 if (r < 0) {
 156
 157                         if (r == -EBADMSG) {
 158                                 puts("Bad input, please try again.");
 159                                 continue;
 160                         }
 161
 162                         putchar('\n');
 163                         return r;
 164                 }
 165
 166                 if (need_nl)
 167                         putchar('\n');
 168
 169                 if (strchr(replies, c)) {
 170                         *ret = c;
 171                         return 0;
 172                 }
 173
 174                 puts("Read unexpected character, please try again.");
 175         }
 176 }
 177
 178 int ask_string(char **ret, const char *text, ...) {
 179         assert(ret);
 180         assert(text);
 181
 182         for (;;) {
 183                 char line[LINE_MAX];
 184                 va_list ap;
 185
 186                 if (on_tty())
 187                         fputs(ANSI_HIGHLIGHT, stdout);
 188
 189                 va_start(ap, text);
 190                 vprintf(text, ap);
 191                 va_end(ap);
 192
 193                 if (on_tty())
 194                         fputs(ANSI_NORMAL, stdout);
 195
 196                 fflush(stdout);
 197
 198                 errno = 0;
 199                 if (!fgets(line, sizeof(line), stdin))
 200                         return errno ? -errno : -EIO;
 201
 202                 if (!endswith(line, "\n"))
 203                         putchar('\n');
 204                 else {
 205                         char *s;
 206
 207                         if (isempty(line))
 208                                 continue;
 209
 210                         truncate_nl(line);
 211                         s = strdup(line);
 212                         if (!s)
 213                                 return -ENOMEM;
 214
 215                         *ret = s;
 216                         return 0;
 217                 }
 218         }
 219 }
 220
 221 int reset_terminal_fd(int fd, bool switch_to_text) {
 222         struct termios termios;
 223         int r = 0;
 224
 225         /* Set terminal to some sane defaults */
 226
 227         assert(fd >= 0);
 228
 229         /* We leave locked terminal attributes untouched, so that
 230          * Plymouth may set whatever it wants to set, and we don't
 231          * interfere with that. */
 232
 233         /* Disable exclusive mode, just in case */
 234         (void) ioctl(fd, TIOCNXCL);
 235
 236         /* Switch to text mode */
 237         if (switch_to_text)
 238                 (void) ioctl(fd, KDSETMODE, KD_TEXT);
 239
 240         /* Enable console unicode mode */
 241         (void) ioctl(fd, KDSKBMODE, K_UNICODE);
 242
 243         if (tcgetattr(fd, &termios) < 0) {
 244                 r = -errno;
 245                 goto finish;
 246         }
 247
 248         /* We only reset the stuff that matters to the software. How
 249          * hardware is set up we don't touch assuming that somebody
 250          * else will do that for us */
 251
 252         termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
 253         termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
 254         termios.c_oflag |= ONLCR;
 255         termios.c_cflag |= CREAD;
 256         termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
 257
 258         termios.c_cc[VINTR]    =   03;  /* ^C */
 259         termios.c_cc[VQUIT]    =  034;  /* ^\ */
 260         termios.c_cc[VERASE]   = 0177;
 261         termios.c_cc[VKILL]    =  025;  /* ^X */
 262         termios.c_cc[VEOF]     =   04;  /* ^D */
 263         termios.c_cc[VSTART]   =  021;  /* ^Q */
 264         termios.c_cc[VSTOP]    =  023;  /* ^S */
 265         termios.c_cc[VSUSP]    =  032;  /* ^Z */
 266         termios.c_cc[VLNEXT]   =  026;  /* ^V */
 267         termios.c_cc[VWERASE]  =  027;  /* ^W */
 268         termios.c_cc[VREPRINT] =  022;  /* ^R */
 269         termios.c_cc[VEOL]     =    0;
 270         termios.c_cc[VEOL2]    =    0;
 271
 272         termios.c_cc[VTIME]  = 0;
 273         termios.c_cc[VMIN]   = 1;
 274
 275         if (tcsetattr(fd, TCSANOW, &termios) < 0)
 276                 r = -errno;
 277
 278 finish:
 279         /* Just in case, flush all crap out */
 280         (void) tcflush(fd, TCIOFLUSH);
 281
 282         return r;
 283 }
 284
 285 int reset_terminal(const char *name) {
 286         _cleanup_close_ int fd = -1;
 287
 288         /* We open the terminal with O_NONBLOCK here, to ensure we
 289          * don't block on carrier if this is a terminal with carrier
 290          * configured. */
 291
 292         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 293         if (fd < 0)
 294                 return fd;
 295
 296         return reset_terminal_fd(fd, true);
 297 }
 298
 299 int open_terminal(const char *name, int mode) {
 300         int fd, r;
 301         unsigned c = 0;
 302
 303         /*
 304          * If a TTY is in the process of being closed opening it might
 305          * cause EIO. This is horribly awful, but unlikely to be
 306          * changed in the kernel. Hence we work around this problem by
 307          * retrying a couple of times.
 308          *
 309          * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
 310          */
 311
 312         if (mode & O_CREAT)
 313                 return -EINVAL;
 314
 315         for (;;) {
 316                 fd = open(name, mode, 0);
 317                 if (fd >= 0)
 318                         break;
 319
 320                 if (errno != EIO)
 321                         return -errno;
 322
 323                 /* Max 1s in total */
 324                 if (c >= 20)
 325                         return -errno;
 326
 327                 usleep(50 * USEC_PER_MSEC);
 328                 c++;
 329         }
 330
 331         r = isatty(fd);
 332         if (r < 0) {
 333                 safe_close(fd);
 334                 return -errno;
 335         }
 336
 337         if (!r) {
 338                 safe_close(fd);
 339                 return -ENOTTY;
 340         }
 341
 342         return fd;
 343 }
 344
 345 int acquire_terminal(
 346                 const char *name,
 347                 bool fail,
 348                 bool force,
 349                 bool ignore_tiocstty_eperm,
 350                 usec_t timeout) {
 351
 352         int fd = -1, notify = -1, r = 0, wd = -1;
 353         usec_t ts = 0;
 354
 355         assert(name);
 356
 357         /* We use inotify to be notified when the tty is closed. We
 358          * create the watch before checking if we can actually acquire
 359          * it, so that we don't lose any event.
 360          *
 361          * Note: strictly speaking this actually watches for the
 362          * device being closed, it does *not* really watch whether a
 363          * tty loses its controlling process. However, unless some
 364          * rogue process uses TIOCNOTTY on /dev/tty *after* closing
 365          * its tty otherwise this will not become a problem. As long
 366          * as the administrator makes sure not configure any service
 367          * on the same tty as an untrusted user this should not be a
 368          * problem. (Which he probably should not do anyway.) */
 369
 370         if (timeout != USEC_INFINITY)
 371                 ts = now(CLOCK_MONOTONIC);
 372
 373         if (!fail && !force) {
 374                 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
 375                 if (notify < 0) {
 376                         r = -errno;
 377                         goto fail;
 378                 }
 379
 380                 wd = inotify_add_watch(notify, name, IN_CLOSE);
 381                 if (wd < 0) {
 382                         r = -errno;
 383                         goto fail;
 384                 }
 385         }
 386
 387         for (;;) {
 388                 struct sigaction sa_old, sa_new = {
 389                         .sa_handler = SIG_IGN,
 390                         .sa_flags = SA_RESTART,
 391                 };
 392
 393                 if (notify >= 0) {
 394                         r = flush_fd(notify);
 395                         if (r < 0)
 396                                 goto fail;
 397                 }
 398
 399                 /* We pass here O_NOCTTY only so that we can check the return
 400                  * value TIOCSCTTY and have a reliable way to figure out if we
 401                  * successfully became the controlling process of the tty */
 402                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 403                 if (fd < 0)
 404                         return fd;
 405
 406                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 407                  * if we already own the tty. */
 408                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 409
 410                 /* First, try to get the tty */
 411                 if (ioctl(fd, TIOCSCTTY, force) < 0)
 412                         r = -errno;
 413
 414                 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 415
 416                 /* Sometimes it makes sense to ignore TIOCSCTTY
 417                  * returning EPERM, i.e. when very likely we already
 418                  * are have this controlling terminal. */
 419                 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
 420                         r = 0;
 421
 422                 if (r < 0 && (force || fail || r != -EPERM))
 423                         goto fail;
 424
 425                 if (r >= 0)
 426                         break;
 427
 428                 assert(!fail);
 429                 assert(!force);
 430                 assert(notify >= 0);
 431
 432                 for (;;) {
 433                         union inotify_event_buffer buffer;
 434                         struct inotify_event *e;
 435                         ssize_t l;
 436
 437                         if (timeout != USEC_INFINITY) {
 438                                 usec_t n;
 439
 440                                 n = now(CLOCK_MONOTONIC);
 441                                 if (ts + timeout < n) {
 442                                         r = -ETIMEDOUT;
 443                                         goto fail;
 444                                 }
 445
 446                                 r = fd_wait_for_event(fd, POLLIN, ts + timeout - n);
 447                                 if (r < 0)
 448                                         goto fail;
 449
 450                                 if (r == 0) {
 451                                         r = -ETIMEDOUT;
 452                                         goto fail;
 453                                 }
 454                         }
 455
 456                         l = read(notify, &buffer, sizeof(buffer));
 457                         if (l < 0) {
 458                                 if (errno == EINTR || errno == EAGAIN)
 459                                         continue;
 460
 461                                 r = -errno;
 462                                 goto fail;
 463                         }
 464
 465                         FOREACH_INOTIFY_EVENT(e, buffer, l) {
 466                                 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
 467                                         r = -EIO;
 468                                         goto fail;
 469                                 }
 470                         }
 471
 472                         break;
 473                 }
 474
 475                 /* We close the tty fd here since if the old session
 476                  * ended our handle will be dead. It's important that
 477                  * we do this after sleeping, so that we don't enter
 478                  * an endless loop. */
 479                 fd = safe_close(fd);
 480         }
 481
 482         safe_close(notify);
 483
 484         return fd;
 485
 486 fail:
 487         safe_close(fd);
 488         safe_close(notify);
 489
 490         return r;
 491 }
 492
 493 int release_terminal(void) {
 494         static const struct sigaction sa_new = {
 495                 .sa_handler = SIG_IGN,
 496                 .sa_flags = SA_RESTART,
 497         };
 498
 499         _cleanup_close_ int fd = -1;
 500         struct sigaction sa_old;
 501         int r = 0;
 502
 503         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 504         if (fd < 0)
 505                 return -errno;
 506
 507         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 508          * by our own TIOCNOTTY */
 509         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 510
 511         if (ioctl(fd, TIOCNOTTY) < 0)
 512                 r = -errno;
 513
 514         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 515
 516         return r;
 517 }
 518
 519 int terminal_vhangup_fd(int fd) {
 520         assert(fd >= 0);
 521
 522         if (ioctl(fd, TIOCVHANGUP) < 0)
 523                 return -errno;
 524
 525         return 0;
 526 }
 527
 528 int terminal_vhangup(const char *name) {
 529         _cleanup_close_ int fd;
 530
 531         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 532         if (fd < 0)
 533                 return fd;
 534
 535         return terminal_vhangup_fd(fd);
 536 }
 537
 538 int vt_disallocate(const char *name) {
 539         _cleanup_close_ int fd = -1;
 540         unsigned u;
 541         int r;
 542
 543         /* Deallocate the VT if possible. If not possible
 544          * (i.e. because it is the active one), at least clear it
 545          * entirely (including the scrollback buffer) */
 546
 547         if (!startswith(name, "/dev/"))
 548                 return -EINVAL;
 549
 550         if (!tty_is_vc(name)) {
 551                 /* So this is not a VT. I guess we cannot deallocate
 552                  * it then. But let's at least clear the screen */
 553
 554                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 555                 if (fd < 0)
 556                         return fd;
 557
 558                 loop_write(fd,
 559                            "\033[r"    /* clear scrolling region */
 560                            "\033[H"    /* move home */
 561                            "\033[2J",  /* clear screen */
 562                            10, false);
 563                 return 0;
 564         }
 565
 566         if (!startswith(name, "/dev/tty"))
 567                 return -EINVAL;
 568
 569         r = safe_atou(name+8, &u);
 570         if (r < 0)
 571                 return r;
 572
 573         if (u <= 0)
 574                 return -EINVAL;
 575
 576         /* Try to deallocate */
 577         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 578         if (fd < 0)
 579                 return fd;
 580
 581         r = ioctl(fd, VT_DISALLOCATE, u);
 582         fd = safe_close(fd);
 583
 584         if (r >= 0)
 585                 return 0;
 586
 587         if (errno != EBUSY)
 588                 return -errno;
 589
 590         /* Couldn't deallocate, so let's clear it fully with
 591          * scrollback */
 592         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 593         if (fd < 0)
 594                 return fd;
 595
 596         loop_write(fd,
 597                    "\033[r"   /* clear scrolling region */
 598                    "\033[H"   /* move home */
 599                    "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
 600                    10, false);
 601         return 0;
 602 }
 603
 604 int make_console_stdio(void) {
 605         int fd, r;
 606
 607         /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
 608
 609         fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
 610         if (fd < 0)
 611                 return log_error_errno(fd, "Failed to acquire terminal: %m");
 612
 613         r = reset_terminal_fd(fd, true);
 614         if (r < 0)
 615                 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
 616
 617         r = make_stdio(fd);
 618         if (r < 0)
 619                 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
 620
 621         return 0;
 622 }
 623
 624 int status_vprintf(const char *status, bool ellipse, bool ephemeral, const char *format, va_list ap) {
 625         static const char status_indent[] = "         "; /* "[" STATUS "] " */
 626         _cleanup_free_ char *s = NULL;
 627         _cleanup_close_ int fd = -1;
 628         struct iovec iovec[6] = {};
 629         int n = 0;
 630         static bool prev_ephemeral;
 631
 632         assert(format);
 633
 634         /* This is independent of logging, as status messages are
 635          * optional and go exclusively to the console. */
 636
 637         if (vasprintf(&s, format, ap) < 0)
 638                 return log_oom();
 639
 640         fd = open_terminal("/dev/console", O_WRONLY|O_NOCTTY|O_CLOEXEC);
 641         if (fd < 0)
 642                 return fd;
 643
 644         if (ellipse) {
 645                 char *e;
 646                 size_t emax, sl;
 647                 int c;
 648
 649                 c = fd_columns(fd);
 650                 if (c <= 0)
 651                         c = 80;
 652
 653                 sl = status ? sizeof(status_indent)-1 : 0;
 654
 655                 emax = c - sl - 1;
 656                 if (emax < 3)
 657                         emax = 3;
 658
 659                 e = ellipsize(s, emax, 50);
 660                 if (e) {
 661                         free(s);
 662                         s = e;
 663                 }
 664         }
 665
 666         if (prev_ephemeral)
 667                 IOVEC_SET_STRING(iovec[n++], "\r" ANSI_ERASE_TO_END_OF_LINE);
 668         prev_ephemeral = ephemeral;
 669
 670         if (status) {
 671                 if (!isempty(status)) {
 672                         IOVEC_SET_STRING(iovec[n++], "[");
 673                         IOVEC_SET_STRING(iovec[n++], status);
 674                         IOVEC_SET_STRING(iovec[n++], "] ");
 675                 } else
 676                         IOVEC_SET_STRING(iovec[n++], status_indent);
 677         }
 678
 679         IOVEC_SET_STRING(iovec[n++], s);
 680         if (!ephemeral)
 681                 IOVEC_SET_STRING(iovec[n++], "\n");
 682
 683         if (writev(fd, iovec, n) < 0)
 684                 return -errno;
 685
 686         return 0;
 687 }
 688
 689 int status_printf(const char *status, bool ellipse, bool ephemeral, const char *format, ...) {
 690         va_list ap;
 691         int r;
 692
 693         assert(format);
 694
 695         va_start(ap, format);
 696         r = status_vprintf(status, ellipse, ephemeral, format, ap);
 697         va_end(ap);
 698
 699         return r;
 700 }
 701
 702 bool tty_is_vc(const char *tty) {
 703         assert(tty);
 704
 705         return vtnr_from_tty(tty) >= 0;
 706 }
 707
 708 bool tty_is_console(const char *tty) {
 709         assert(tty);
 710
 711         if (startswith(tty, "/dev/"))
 712                 tty += 5;
 713
 714         return streq(tty, "console");
 715 }
 716
 717 int vtnr_from_tty(const char *tty) {
 718         int i, r;
 719
 720         assert(tty);
 721
 722         if (startswith(tty, "/dev/"))
 723                 tty += 5;
 724
 725         if (!startswith(tty, "tty") )
 726                 return -EINVAL;
 727
 728         if (tty[3] < '0' || tty[3] > '9')
 729                 return -EINVAL;
 730
 731         r = safe_atoi(tty+3, &i);
 732         if (r < 0)
 733                 return r;
 734
 735         if (i < 0 || i > 63)
 736                 return -EINVAL;
 737
 738         return i;
 739 }
 740
 741 char *resolve_dev_console(char **active) {
 742         char *tty;
 743
 744         /* Resolve where /dev/console is pointing to, if /sys is actually ours
 745          * (i.e. not read-only-mounted which is a sign for container setups) */
 746
 747         if (path_is_read_only_fs("/sys") > 0)
 748                 return NULL;
 749
 750         if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
 751                 return NULL;
 752
 753         /* If multiple log outputs are configured the last one is what
 754          * /dev/console points to */
 755         tty = strrchr(*active, ' ');
 756         if (tty)
 757                 tty++;
 758         else
 759                 tty = *active;
 760
 761         if (streq(tty, "tty0")) {
 762                 char *tmp;
 763
 764                 /* Get the active VC (e.g. tty1) */
 765                 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
 766                         free(*active);
 767                         tty = *active = tmp;
 768                 }
 769         }
 770
 771         return tty;
 772 }
 773
 774 bool tty_is_vc_resolve(const char *tty) {
 775         _cleanup_free_ char *active = NULL;
 776
 777         assert(tty);
 778
 779         if (startswith(tty, "/dev/"))
 780                 tty += 5;
 781
 782         if (streq(tty, "console")) {
 783                 tty = resolve_dev_console(&active);
 784                 if (!tty)
 785                         return false;
 786         }
 787
 788         return tty_is_vc(tty);
 789 }
 790
 791 const char *default_term_for_tty(const char *tty) {
 792         assert(tty);
 793
 794         return tty_is_vc_resolve(tty) ? "TERM=linux" : "TERM=vt220";
 795 }
 796
 797 int fd_columns(int fd) {
 798         struct winsize ws = {};
 799
 800         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 801                 return -errno;
 802
 803         if (ws.ws_col <= 0)
 804                 return -EIO;
 805
 806         return ws.ws_col;
 807 }
 808
 809 unsigned columns(void) {
 810         const char *e;
 811         int c;
 812
 813         if (_likely_(cached_columns > 0))
 814                 return cached_columns;
 815
 816         c = 0;
 817         e = getenv("COLUMNS");
 818         if (e)
 819                 (void) safe_atoi(e, &c);
 820
 821         if (c <= 0)
 822                 c = fd_columns(STDOUT_FILENO);
 823
 824         if (c <= 0)
 825                 c = 80;
 826
 827         cached_columns = c;
 828         return cached_columns;
 829 }
 830
 831 int fd_lines(int fd) {
 832         struct winsize ws = {};
 833
 834         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 835                 return -errno;
 836
 837         if (ws.ws_row <= 0)
 838                 return -EIO;
 839
 840         return ws.ws_row;
 841 }
 842
 843 unsigned lines(void) {
 844         const char *e;
 845         int l;
 846
 847         if (_likely_(cached_lines > 0))
 848                 return cached_lines;
 849
 850         l = 0;
 851         e = getenv("LINES");
 852         if (e)
 853                 (void) safe_atoi(e, &l);
 854
 855         if (l <= 0)
 856                 l = fd_lines(STDOUT_FILENO);
 857
 858         if (l <= 0)
 859                 l = 24;
 860
 861         cached_lines = l;
 862         return cached_lines;
 863 }
 864
 865 /* intended to be used as a SIGWINCH sighandler */
 866 void columns_lines_cache_reset(int signum) {
 867         cached_columns = 0;
 868         cached_lines = 0;
 869 }
 870
 871 bool on_tty(void) {
 872         static int cached_on_tty = -1;
 873
 874         if (_unlikely_(cached_on_tty < 0))
 875                 cached_on_tty = isatty(STDOUT_FILENO) > 0;
 876
 877         return cached_on_tty;
 878 }
 879
 880 int make_stdio(int fd) {
 881         int r, s, t;
 882
 883         assert(fd >= 0);
 884
 885         r = dup2(fd, STDIN_FILENO);
 886         s = dup2(fd, STDOUT_FILENO);
 887         t = dup2(fd, STDERR_FILENO);
 888
 889         if (fd >= 3)
 890                 safe_close(fd);
 891
 892         if (r < 0 || s < 0 || t < 0)
 893                 return -errno;
 894
 895         /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
 896          * dup2() was a NOP and the bit hence possibly set. */
 897         fd_cloexec(STDIN_FILENO, false);
 898         fd_cloexec(STDOUT_FILENO, false);
 899         fd_cloexec(STDERR_FILENO, false);
 900
 901         return 0;
 902 }
 903
 904 int make_null_stdio(void) {
 905         int null_fd;
 906
 907         null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
 908         if (null_fd < 0)
 909                 return -errno;
 910
 911         return make_stdio(null_fd);
 912 }
 913
 914 int getttyname_malloc(int fd, char **ret) {
 915         size_t l = 100;
 916         int r;
 917
 918         assert(fd >= 0);
 919         assert(ret);
 920
 921         for (;;) {
 922                 char path[l];
 923
 924                 r = ttyname_r(fd, path, sizeof(path));
 925                 if (r == 0) {
 926                         const char *p;
 927                         char *c;
 928
 929                         p = startswith(path, "/dev/");
 930                         c = strdup(p ?: path);
 931                         if (!c)
 932                                 return -ENOMEM;
 933
 934                         *ret = c;
 935                         return 0;
 936                 }
 937
 938                 if (r != ERANGE)
 939                         return -r;
 940
 941                 l *= 2;
 942         }
 943
 944         return 0;
 945 }
 946
 947 int getttyname_harder(int fd, char **r) {
 948         int k;
 949         char *s = NULL;
 950
 951         k = getttyname_malloc(fd, &s);
 952         if (k < 0)
 953                 return k;
 954
 955         if (streq(s, "tty")) {
 956                 free(s);
 957                 return get_ctty(0, NULL, r);
 958         }
 959
 960         *r = s;
 961         return 0;
 962 }
 963
 964 int get_ctty_devnr(pid_t pid, dev_t *d) {
 965         int r;
 966         _cleanup_free_ char *line = NULL;
 967         const char *p;
 968         unsigned long ttynr;
 969
 970         assert(pid >= 0);
 971
 972         p = procfs_file_alloca(pid, "stat");
 973         r = read_one_line_file(p, &line);
 974         if (r < 0)
 975                 return r;
 976
 977         p = strrchr(line, ')');
 978         if (!p)
 979                 return -EIO;
 980
 981         p++;
 982
 983         if (sscanf(p, " "
 984                    "%*c "  /* state */
 985                    "%*d "  /* ppid */
 986                    "%*d "  /* pgrp */
 987                    "%*d "  /* session */
 988                    "%lu ", /* ttynr */
 989                    &ttynr) != 1)
 990                 return -EIO;
 991
 992         if (major(ttynr) == 0 && minor(ttynr) == 0)
 993                 return -ENXIO;
 994
 995         if (d)
 996                 *d = (dev_t) ttynr;
 997
 998         return 0;
 999 }
1000
1001 int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
1002         char fn[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL;
1003         _cleanup_free_ char *s = NULL;
1004         const char *p;
1005         dev_t devnr;
1006         int k;
1007
1008         assert(r);
1009
1010         k = get_ctty_devnr(pid, &devnr);
1011         if (k < 0)
1012                 return k;
1013
1014         sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr));
1015
1016         k = readlink_malloc(fn, &s);
1017         if (k < 0) {
1018
1019                 if (k != -ENOENT)
1020                         return k;
1021
1022                 /* This is an ugly hack */
1023                 if (major(devnr) == 136) {
1024                         if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
1025                                 return -ENOMEM;
1026                 } else {
1027                         /* Probably something like the ptys which have no
1028                          * symlink in /dev/char. Let's return something
1029                          * vaguely useful. */
1030
1031                         b = strdup(fn + 5);
1032                         if (!b)
1033                                 return -ENOMEM;
1034                 }
1035         } else {
1036                 if (startswith(s, "/dev/"))
1037                         p = s + 5;
1038                 else if (startswith(s, "../"))
1039                         p = s + 3;
1040                 else
1041                         p = s;
1042
1043                 b = strdup(p);
1044                 if (!b)
1045                         return -ENOMEM;
1046         }
1047
1048         *r = b;
1049         if (_devnr)
1050                 *_devnr = devnr;
1051
1052         return 0;
1053 }
1054
1055 int ptsname_malloc(int fd, char **ret) {
1056         size_t l = 100;
1057
1058         assert(fd >= 0);
1059         assert(ret);
1060
1061         for (;;) {
1062                 char *c;
1063
1064                 c = new(char, l);
1065                 if (!c)
1066                         return -ENOMEM;
1067
1068                 if (ptsname_r(fd, c, l) == 0) {
1069                         *ret = c;
1070                         return 0;
1071                 }
1072                 if (errno != ERANGE) {
1073                         free(c);
1074                         return -errno;
1075                 }
1076
1077                 free(c);
1078                 l *= 2;
1079         }
1080 }
1081
1082 int ptsname_namespace(int pty, char **ret) {
1083         int no = -1, r;
1084
1085         /* Like ptsname(), but doesn't assume that the path is
1086          * accessible in the local namespace. */
1087
1088         r = ioctl(pty, TIOCGPTN, &no);
1089         if (r < 0)
1090                 return -errno;
1091
1092         if (no < 0)
1093                 return -EIO;
1094
1095         if (asprintf(ret, "/dev/pts/%i", no) < 0)
1096                 return -ENOMEM;
1097
1098         return 0;
1099 }
1100
1101 int openpt_in_namespace(pid_t pid, int flags) {
1102         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1103         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1104         siginfo_t si;
1105         pid_t child;
1106         int r;
1107
1108         assert(pid > 0);
1109
1110         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1111         if (r < 0)
1112                 return r;
1113
1114         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1115                 return -errno;
1116
1117         child = fork();
1118         if (child < 0)
1119                 return -errno;
1120
1121         if (child == 0) {
1122                 int master;
1123
1124                 pair[0] = safe_close(pair[0]);
1125
1126                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1127                 if (r < 0)
1128                         _exit(EXIT_FAILURE);
1129
1130                 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1131                 if (master < 0)
1132                         _exit(EXIT_FAILURE);
1133
1134                 if (unlockpt(master) < 0)
1135                         _exit(EXIT_FAILURE);
1136
1137                 if (send_one_fd(pair[1], master, 0) < 0)
1138                         _exit(EXIT_FAILURE);
1139
1140                 _exit(EXIT_SUCCESS);
1141         }
1142
1143         pair[1] = safe_close(pair[1]);
1144
1145         r = wait_for_terminate(child, &si);
1146         if (r < 0)
1147                 return r;
1148         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1149                 return -EIO;
1150
1151         return receive_one_fd(pair[0], 0);
1152 }
1153
1154 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1155         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1156         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1157         siginfo_t si;
1158         pid_t child;
1159         int r;
1160
1161         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1162         if (r < 0)
1163                 return r;
1164
1165         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1166                 return -errno;
1167
1168         child = fork();
1169         if (child < 0)
1170                 return -errno;
1171
1172         if (child == 0) {
1173                 int master;
1174
1175                 pair[0] = safe_close(pair[0]);
1176
1177                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1178                 if (r < 0)
1179                         _exit(EXIT_FAILURE);
1180
1181                 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1182                 if (master < 0)
1183                         _exit(EXIT_FAILURE);
1184
1185                 if (send_one_fd(pair[1], master, 0) < 0)
1186                         _exit(EXIT_FAILURE);
1187
1188                 _exit(EXIT_SUCCESS);
1189         }
1190
1191         pair[1] = safe_close(pair[1]);
1192
1193         r = wait_for_terminate(child, &si);
1194         if (r < 0)
1195                 return r;
1196         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1197                 return -EIO;
1198
1199         return receive_one_fd(pair[0], 0);
1200 }