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 "fd-util.h"
  35 #include "fileio.h"
  36 #include "path-util.h"
  37 #include "process-util.h"
  38 #include "string-util.h"
  39 #include "terminal-util.h"
  40 #include "time-util.h"
  41 #include "util.h"
  42
  43 static volatile unsigned cached_columns = 0;
  44 static volatile unsigned cached_lines = 0;
  45
  46 int chvt(int vt) {
  47         _cleanup_close_ int fd;
  48
  49         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
  50         if (fd < 0)
  51                 return -errno;
  52
  53         if (vt <= 0) {
  54                 int tiocl[2] = {
  55                         TIOCL_GETKMSGREDIRECT,
  56                         0
  57                 };
  58
  59                 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
  60                         return -errno;
  61
  62                 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
  63         }
  64
  65         if (ioctl(fd, VT_ACTIVATE, vt) < 0)
  66                 return -errno;
  67
  68         return 0;
  69 }
  70
  71 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
  72         struct termios old_termios, new_termios;
  73         char c, line[LINE_MAX];
  74
  75         assert(f);
  76         assert(ret);
  77
  78         if (tcgetattr(fileno(f), &old_termios) >= 0) {
  79                 new_termios = old_termios;
  80
  81                 new_termios.c_lflag &= ~ICANON;
  82                 new_termios.c_cc[VMIN] = 1;
  83                 new_termios.c_cc[VTIME] = 0;
  84
  85                 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
  86                         size_t k;
  87
  88                         if (t != USEC_INFINITY) {
  89                                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
  90                                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
  91                                         return -ETIMEDOUT;
  92                                 }
  93                         }
  94
  95                         k = fread(&c, 1, 1, f);
  96
  97                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
  98
  99                         if (k <= 0)
 100                                 return -EIO;
 101
 102                         if (need_nl)
 103                                 *need_nl = c != '\n';
 104
 105                         *ret = c;
 106                         return 0;
 107                 }
 108         }
 109
 110         if (t != USEC_INFINITY) {
 111                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
 112                         return -ETIMEDOUT;
 113         }
 114
 115         errno = 0;
 116         if (!fgets(line, sizeof(line), f))
 117                 return errno ? -errno : -EIO;
 118
 119         truncate_nl(line);
 120
 121         if (strlen(line) != 1)
 122                 return -EBADMSG;
 123
 124         if (need_nl)
 125                 *need_nl = false;
 126
 127         *ret = line[0];
 128         return 0;
 129 }
 130
 131 int ask_char(char *ret, const char *replies, const char *text, ...) {
 132         int r;
 133
 134         assert(ret);
 135         assert(replies);
 136         assert(text);
 137
 138         for (;;) {
 139                 va_list ap;
 140                 char c;
 141                 bool need_nl = true;
 142
 143                 if (on_tty())
 144                         fputs(ANSI_HIGHLIGHT, stdout);
 145
 146                 va_start(ap, text);
 147                 vprintf(text, ap);
 148                 va_end(ap);
 149
 150                 if (on_tty())
 151                         fputs(ANSI_NORMAL, stdout);
 152
 153                 fflush(stdout);
 154
 155                 r = read_one_char(stdin, &c, USEC_INFINITY, &need_nl);
 156                 if (r < 0) {
 157
 158                         if (r == -EBADMSG) {
 159                                 puts("Bad input, please try again.");
 160                                 continue;
 161                         }
 162
 163                         putchar('\n');
 164                         return r;
 165                 }
 166
 167                 if (need_nl)
 168                         putchar('\n');
 169
 170                 if (strchr(replies, c)) {
 171                         *ret = c;
 172                         return 0;
 173                 }
 174
 175                 puts("Read unexpected character, please try again.");
 176         }
 177 }
 178
 179 int ask_string(char **ret, const char *text, ...) {
 180         assert(ret);
 181         assert(text);
 182
 183         for (;;) {
 184                 char line[LINE_MAX];
 185                 va_list ap;
 186
 187                 if (on_tty())
 188                         fputs(ANSI_HIGHLIGHT, stdout);
 189
 190                 va_start(ap, text);
 191                 vprintf(text, ap);
 192                 va_end(ap);
 193
 194                 if (on_tty())
 195                         fputs(ANSI_NORMAL, stdout);
 196
 197                 fflush(stdout);
 198
 199                 errno = 0;
 200                 if (!fgets(line, sizeof(line), stdin))
 201                         return errno ? -errno : -EIO;
 202
 203                 if (!endswith(line, "\n"))
 204                         putchar('\n');
 205                 else {
 206                         char *s;
 207
 208                         if (isempty(line))
 209                                 continue;
 210
 211                         truncate_nl(line);
 212                         s = strdup(line);
 213                         if (!s)
 214                                 return -ENOMEM;
 215
 216                         *ret = s;
 217                         return 0;
 218                 }
 219         }
 220 }
 221
 222 int reset_terminal_fd(int fd, bool switch_to_text) {
 223         struct termios termios;
 224         int r = 0;
 225
 226         /* Set terminal to some sane defaults */
 227
 228         assert(fd >= 0);
 229
 230         /* We leave locked terminal attributes untouched, so that
 231          * Plymouth may set whatever it wants to set, and we don't
 232          * interfere with that. */
 233
 234         /* Disable exclusive mode, just in case */
 235         (void) ioctl(fd, TIOCNXCL);
 236
 237         /* Switch to text mode */
 238         if (switch_to_text)
 239                 (void) ioctl(fd, KDSETMODE, KD_TEXT);
 240
 241         /* Enable console unicode mode */
 242         (void) ioctl(fd, KDSKBMODE, K_UNICODE);
 243
 244         if (tcgetattr(fd, &termios) < 0) {
 245                 r = -errno;
 246                 goto finish;
 247         }
 248
 249         /* We only reset the stuff that matters to the software. How
 250          * hardware is set up we don't touch assuming that somebody
 251          * else will do that for us */
 252
 253         termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
 254         termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
 255         termios.c_oflag |= ONLCR;
 256         termios.c_cflag |= CREAD;
 257         termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
 258
 259         termios.c_cc[VINTR]    =   03;  /* ^C */
 260         termios.c_cc[VQUIT]    =  034;  /* ^\ */
 261         termios.c_cc[VERASE]   = 0177;
 262         termios.c_cc[VKILL]    =  025;  /* ^X */
 263         termios.c_cc[VEOF]     =   04;  /* ^D */
 264         termios.c_cc[VSTART]   =  021;  /* ^Q */
 265         termios.c_cc[VSTOP]    =  023;  /* ^S */
 266         termios.c_cc[VSUSP]    =  032;  /* ^Z */
 267         termios.c_cc[VLNEXT]   =  026;  /* ^V */
 268         termios.c_cc[VWERASE]  =  027;  /* ^W */
 269         termios.c_cc[VREPRINT] =  022;  /* ^R */
 270         termios.c_cc[VEOL]     =    0;
 271         termios.c_cc[VEOL2]    =    0;
 272
 273         termios.c_cc[VTIME]  = 0;
 274         termios.c_cc[VMIN]   = 1;
 275
 276         if (tcsetattr(fd, TCSANOW, &termios) < 0)
 277                 r = -errno;
 278
 279 finish:
 280         /* Just in case, flush all crap out */
 281         (void) tcflush(fd, TCIOFLUSH);
 282
 283         return r;
 284 }
 285
 286 int reset_terminal(const char *name) {
 287         _cleanup_close_ int fd = -1;
 288
 289         /* We open the terminal with O_NONBLOCK here, to ensure we
 290          * don't block on carrier if this is a terminal with carrier
 291          * configured. */
 292
 293         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 294         if (fd < 0)
 295                 return fd;
 296
 297         return reset_terminal_fd(fd, true);
 298 }
 299
 300 int open_terminal(const char *name, int mode) {
 301         int fd, r;
 302         unsigned c = 0;
 303
 304         /*
 305          * If a TTY is in the process of being closed opening it might
 306          * cause EIO. This is horribly awful, but unlikely to be
 307          * changed in the kernel. Hence we work around this problem by
 308          * retrying a couple of times.
 309          *
 310          * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
 311          */
 312
 313         if (mode & O_CREAT)
 314                 return -EINVAL;
 315
 316         for (;;) {
 317                 fd = open(name, mode, 0);
 318                 if (fd >= 0)
 319                         break;
 320
 321                 if (errno != EIO)
 322                         return -errno;
 323
 324                 /* Max 1s in total */
 325                 if (c >= 20)
 326                         return -errno;
 327
 328                 usleep(50 * USEC_PER_MSEC);
 329                 c++;
 330         }
 331
 332         r = isatty(fd);
 333         if (r < 0) {
 334                 safe_close(fd);
 335                 return -errno;
 336         }
 337
 338         if (!r) {
 339                 safe_close(fd);
 340                 return -ENOTTY;
 341         }
 342
 343         return fd;
 344 }
 345
 346 int acquire_terminal(
 347                 const char *name,
 348                 bool fail,
 349                 bool force,
 350                 bool ignore_tiocstty_eperm,
 351                 usec_t timeout) {
 352
 353         int fd = -1, notify = -1, r = 0, wd = -1;
 354         usec_t ts = 0;
 355
 356         assert(name);
 357
 358         /* We use inotify to be notified when the tty is closed. We
 359          * create the watch before checking if we can actually acquire
 360          * it, so that we don't lose any event.
 361          *
 362          * Note: strictly speaking this actually watches for the
 363          * device being closed, it does *not* really watch whether a
 364          * tty loses its controlling process. However, unless some
 365          * rogue process uses TIOCNOTTY on /dev/tty *after* closing
 366          * its tty otherwise this will not become a problem. As long
 367          * as the administrator makes sure not configure any service
 368          * on the same tty as an untrusted user this should not be a
 369          * problem. (Which he probably should not do anyway.) */
 370
 371         if (timeout != USEC_INFINITY)
 372                 ts = now(CLOCK_MONOTONIC);
 373
 374         if (!fail && !force) {
 375                 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
 376                 if (notify < 0) {
 377                         r = -errno;
 378                         goto fail;
 379                 }
 380
 381                 wd = inotify_add_watch(notify, name, IN_CLOSE);
 382                 if (wd < 0) {
 383                         r = -errno;
 384                         goto fail;
 385                 }
 386         }
 387
 388         for (;;) {
 389                 struct sigaction sa_old, sa_new = {
 390                         .sa_handler = SIG_IGN,
 391                         .sa_flags = SA_RESTART,
 392                 };
 393
 394                 if (notify >= 0) {
 395                         r = flush_fd(notify);
 396                         if (r < 0)
 397                                 goto fail;
 398                 }
 399
 400                 /* We pass here O_NOCTTY only so that we can check the return
 401                  * value TIOCSCTTY and have a reliable way to figure out if we
 402                  * successfully became the controlling process of the tty */
 403                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 404                 if (fd < 0)
 405                         return fd;
 406
 407                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 408                  * if we already own the tty. */
 409                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 410
 411                 /* First, try to get the tty */
 412                 if (ioctl(fd, TIOCSCTTY, force) < 0)
 413                         r = -errno;
 414
 415                 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 416
 417                 /* Sometimes it makes sense to ignore TIOCSCTTY
 418                  * returning EPERM, i.e. when very likely we already
 419                  * are have this controlling terminal. */
 420                 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
 421                         r = 0;
 422
 423                 if (r < 0 && (force || fail || r != -EPERM))
 424                         goto fail;
 425
 426                 if (r >= 0)
 427                         break;
 428
 429                 assert(!fail);
 430                 assert(!force);
 431                 assert(notify >= 0);
 432
 433                 for (;;) {
 434                         union inotify_event_buffer buffer;
 435                         struct inotify_event *e;
 436                         ssize_t l;
 437
 438                         if (timeout != USEC_INFINITY) {
 439                                 usec_t n;
 440
 441                                 n = now(CLOCK_MONOTONIC);
 442                                 if (ts + timeout < n) {
 443                                         r = -ETIMEDOUT;
 444                                         goto fail;
 445                                 }
 446
 447                                 r = fd_wait_for_event(fd, POLLIN, ts + timeout - n);
 448                                 if (r < 0)
 449                                         goto fail;
 450
 451                                 if (r == 0) {
 452                                         r = -ETIMEDOUT;
 453                                         goto fail;
 454                                 }
 455                         }
 456
 457                         l = read(notify, &buffer, sizeof(buffer));
 458                         if (l < 0) {
 459                                 if (errno == EINTR || errno == EAGAIN)
 460                                         continue;
 461
 462                                 r = -errno;
 463                                 goto fail;
 464                         }
 465
 466                         FOREACH_INOTIFY_EVENT(e, buffer, l) {
 467                                 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
 468                                         r = -EIO;
 469                                         goto fail;
 470                                 }
 471                         }
 472
 473                         break;
 474                 }
 475
 476                 /* We close the tty fd here since if the old session
 477                  * ended our handle will be dead. It's important that
 478                  * we do this after sleeping, so that we don't enter
 479                  * an endless loop. */
 480                 fd = safe_close(fd);
 481         }
 482
 483         safe_close(notify);
 484
 485         return fd;
 486
 487 fail:
 488         safe_close(fd);
 489         safe_close(notify);
 490
 491         return r;
 492 }
 493
 494 int release_terminal(void) {
 495         static const struct sigaction sa_new = {
 496                 .sa_handler = SIG_IGN,
 497                 .sa_flags = SA_RESTART,
 498         };
 499
 500         _cleanup_close_ int fd = -1;
 501         struct sigaction sa_old;
 502         int r = 0;
 503
 504         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 505         if (fd < 0)
 506                 return -errno;
 507
 508         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 509          * by our own TIOCNOTTY */
 510         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 511
 512         if (ioctl(fd, TIOCNOTTY) < 0)
 513                 r = -errno;
 514
 515         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 516
 517         return r;
 518 }
 519
 520 int terminal_vhangup_fd(int fd) {
 521         assert(fd >= 0);
 522
 523         if (ioctl(fd, TIOCVHANGUP) < 0)
 524                 return -errno;
 525
 526         return 0;
 527 }
 528
 529 int terminal_vhangup(const char *name) {
 530         _cleanup_close_ int fd;
 531
 532         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 533         if (fd < 0)
 534                 return fd;
 535
 536         return terminal_vhangup_fd(fd);
 537 }
 538
 539 int vt_disallocate(const char *name) {
 540         _cleanup_close_ int fd = -1;
 541         unsigned u;
 542         int r;
 543
 544         /* Deallocate the VT if possible. If not possible
 545          * (i.e. because it is the active one), at least clear it
 546          * entirely (including the scrollback buffer) */
 547
 548         if (!startswith(name, "/dev/"))
 549                 return -EINVAL;
 550
 551         if (!tty_is_vc(name)) {
 552                 /* So this is not a VT. I guess we cannot deallocate
 553                  * it then. But let's at least clear the screen */
 554
 555                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 556                 if (fd < 0)
 557                         return fd;
 558
 559                 loop_write(fd,
 560                            "\033[r"    /* clear scrolling region */
 561                            "\033[H"    /* move home */
 562                            "\033[2J",  /* clear screen */
 563                            10, false);
 564                 return 0;
 565         }
 566
 567         if (!startswith(name, "/dev/tty"))
 568                 return -EINVAL;
 569
 570         r = safe_atou(name+8, &u);
 571         if (r < 0)
 572                 return r;
 573
 574         if (u <= 0)
 575                 return -EINVAL;
 576
 577         /* Try to deallocate */
 578         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 579         if (fd < 0)
 580                 return fd;
 581
 582         r = ioctl(fd, VT_DISALLOCATE, u);
 583         fd = safe_close(fd);
 584
 585         if (r >= 0)
 586                 return 0;
 587
 588         if (errno != EBUSY)
 589                 return -errno;
 590
 591         /* Couldn't deallocate, so let's clear it fully with
 592          * scrollback */
 593         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 594         if (fd < 0)
 595                 return fd;
 596
 597         loop_write(fd,
 598                    "\033[r"   /* clear scrolling region */
 599                    "\033[H"   /* move home */
 600                    "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
 601                    10, false);
 602         return 0;
 603 }
 604
 605 int make_console_stdio(void) {
 606         int fd, r;
 607
 608         /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
 609
 610         fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
 611         if (fd < 0)
 612                 return log_error_errno(fd, "Failed to acquire terminal: %m");
 613
 614         r = reset_terminal_fd(fd, true);
 615         if (r < 0)
 616                 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
 617
 618         r = make_stdio(fd);
 619         if (r < 0)
 620                 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
 621
 622         return 0;
 623 }
 624
 625 int status_vprintf(const char *status, bool ellipse, bool ephemeral, const char *format, va_list ap) {
 626         static const char status_indent[] = "         "; /* "[" STATUS "] " */
 627         _cleanup_free_ char *s = NULL;
 628         _cleanup_close_ int fd = -1;
 629         struct iovec iovec[6] = {};
 630         int n = 0;
 631         static bool prev_ephemeral;
 632
 633         assert(format);
 634
 635         /* This is independent of logging, as status messages are
 636          * optional and go exclusively to the console. */
 637
 638         if (vasprintf(&s, format, ap) < 0)
 639                 return log_oom();
 640
 641         fd = open_terminal("/dev/console", O_WRONLY|O_NOCTTY|O_CLOEXEC);
 642         if (fd < 0)
 643                 return fd;
 644
 645         if (ellipse) {
 646                 char *e;
 647                 size_t emax, sl;
 648                 int c;
 649
 650                 c = fd_columns(fd);
 651                 if (c <= 0)
 652                         c = 80;
 653
 654                 sl = status ? sizeof(status_indent)-1 : 0;
 655
 656                 emax = c - sl - 1;
 657                 if (emax < 3)
 658                         emax = 3;
 659
 660                 e = ellipsize(s, emax, 50);
 661                 if (e) {
 662                         free(s);
 663                         s = e;
 664                 }
 665         }
 666
 667         if (prev_ephemeral)
 668                 IOVEC_SET_STRING(iovec[n++], "\r" ANSI_ERASE_TO_END_OF_LINE);
 669         prev_ephemeral = ephemeral;
 670
 671         if (status) {
 672                 if (!isempty(status)) {
 673                         IOVEC_SET_STRING(iovec[n++], "[");
 674                         IOVEC_SET_STRING(iovec[n++], status);
 675                         IOVEC_SET_STRING(iovec[n++], "] ");
 676                 } else
 677                         IOVEC_SET_STRING(iovec[n++], status_indent);
 678         }
 679
 680         IOVEC_SET_STRING(iovec[n++], s);
 681         if (!ephemeral)
 682                 IOVEC_SET_STRING(iovec[n++], "\n");
 683
 684         if (writev(fd, iovec, n) < 0)
 685                 return -errno;
 686
 687         return 0;
 688 }
 689
 690 int status_printf(const char *status, bool ellipse, bool ephemeral, const char *format, ...) {
 691         va_list ap;
 692         int r;
 693
 694         assert(format);
 695
 696         va_start(ap, format);
 697         r = status_vprintf(status, ellipse, ephemeral, format, ap);
 698         va_end(ap);
 699
 700         return r;
 701 }
 702
 703 bool tty_is_vc(const char *tty) {
 704         assert(tty);
 705
 706         return vtnr_from_tty(tty) >= 0;
 707 }
 708
 709 bool tty_is_console(const char *tty) {
 710         assert(tty);
 711
 712         if (startswith(tty, "/dev/"))
 713                 tty += 5;
 714
 715         return streq(tty, "console");
 716 }
 717
 718 int vtnr_from_tty(const char *tty) {
 719         int i, r;
 720
 721         assert(tty);
 722
 723         if (startswith(tty, "/dev/"))
 724                 tty += 5;
 725
 726         if (!startswith(tty, "tty") )
 727                 return -EINVAL;
 728
 729         if (tty[3] < '0' || tty[3] > '9')
 730                 return -EINVAL;
 731
 732         r = safe_atoi(tty+3, &i);
 733         if (r < 0)
 734                 return r;
 735
 736         if (i < 0 || i > 63)
 737                 return -EINVAL;
 738
 739         return i;
 740 }
 741
 742 char *resolve_dev_console(char **active) {
 743         char *tty;
 744
 745         /* Resolve where /dev/console is pointing to, if /sys is actually ours
 746          * (i.e. not read-only-mounted which is a sign for container setups) */
 747
 748         if (path_is_read_only_fs("/sys") > 0)
 749                 return NULL;
 750
 751         if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
 752                 return NULL;
 753
 754         /* If multiple log outputs are configured the last one is what
 755          * /dev/console points to */
 756         tty = strrchr(*active, ' ');
 757         if (tty)
 758                 tty++;
 759         else
 760                 tty = *active;
 761
 762         if (streq(tty, "tty0")) {
 763                 char *tmp;
 764
 765                 /* Get the active VC (e.g. tty1) */
 766                 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
 767                         free(*active);
 768                         tty = *active = tmp;
 769                 }
 770         }
 771
 772         return tty;
 773 }
 774
 775 bool tty_is_vc_resolve(const char *tty) {
 776         _cleanup_free_ char *active = NULL;
 777
 778         assert(tty);
 779
 780         if (startswith(tty, "/dev/"))
 781                 tty += 5;
 782
 783         if (streq(tty, "console")) {
 784                 tty = resolve_dev_console(&active);
 785                 if (!tty)
 786                         return false;
 787         }
 788
 789         return tty_is_vc(tty);
 790 }
 791
 792 const char *default_term_for_tty(const char *tty) {
 793         assert(tty);
 794
 795         return tty_is_vc_resolve(tty) ? "TERM=linux" : "TERM=vt220";
 796 }
 797
 798 int fd_columns(int fd) {
 799         struct winsize ws = {};
 800
 801         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 802                 return -errno;
 803
 804         if (ws.ws_col <= 0)
 805                 return -EIO;
 806
 807         return ws.ws_col;
 808 }
 809
 810 unsigned columns(void) {
 811         const char *e;
 812         int c;
 813
 814         if (_likely_(cached_columns > 0))
 815                 return cached_columns;
 816
 817         c = 0;
 818         e = getenv("COLUMNS");
 819         if (e)
 820                 (void) safe_atoi(e, &c);
 821
 822         if (c <= 0)
 823                 c = fd_columns(STDOUT_FILENO);
 824
 825         if (c <= 0)
 826                 c = 80;
 827
 828         cached_columns = c;
 829         return cached_columns;
 830 }
 831
 832 int fd_lines(int fd) {
 833         struct winsize ws = {};
 834
 835         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 836                 return -errno;
 837
 838         if (ws.ws_row <= 0)
 839                 return -EIO;
 840
 841         return ws.ws_row;
 842 }
 843
 844 unsigned lines(void) {
 845         const char *e;
 846         int l;
 847
 848         if (_likely_(cached_lines > 0))
 849                 return cached_lines;
 850
 851         l = 0;
 852         e = getenv("LINES");
 853         if (e)
 854                 (void) safe_atoi(e, &l);
 855
 856         if (l <= 0)
 857                 l = fd_lines(STDOUT_FILENO);
 858
 859         if (l <= 0)
 860                 l = 24;
 861
 862         cached_lines = l;
 863         return cached_lines;
 864 }
 865
 866 /* intended to be used as a SIGWINCH sighandler */
 867 void columns_lines_cache_reset(int signum) {
 868         cached_columns = 0;
 869         cached_lines = 0;
 870 }
 871
 872 bool on_tty(void) {
 873         static int cached_on_tty = -1;
 874
 875         if (_unlikely_(cached_on_tty < 0))
 876                 cached_on_tty = isatty(STDOUT_FILENO) > 0;
 877
 878         return cached_on_tty;
 879 }
 880
 881 int make_stdio(int fd) {
 882         int r, s, t;
 883
 884         assert(fd >= 0);
 885
 886         r = dup2(fd, STDIN_FILENO);
 887         s = dup2(fd, STDOUT_FILENO);
 888         t = dup2(fd, STDERR_FILENO);
 889
 890         if (fd >= 3)
 891                 safe_close(fd);
 892
 893         if (r < 0 || s < 0 || t < 0)
 894                 return -errno;
 895
 896         /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
 897          * dup2() was a NOP and the bit hence possibly set. */
 898         fd_cloexec(STDIN_FILENO, false);
 899         fd_cloexec(STDOUT_FILENO, false);
 900         fd_cloexec(STDERR_FILENO, false);
 901
 902         return 0;
 903 }
 904
 905 int make_null_stdio(void) {
 906         int null_fd;
 907
 908         null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
 909         if (null_fd < 0)
 910                 return -errno;
 911
 912         return make_stdio(null_fd);
 913 }
 914
 915 int getttyname_malloc(int fd, char **ret) {
 916         size_t l = 100;
 917         int r;
 918
 919         assert(fd >= 0);
 920         assert(ret);
 921
 922         for (;;) {
 923                 char path[l];
 924
 925                 r = ttyname_r(fd, path, sizeof(path));
 926                 if (r == 0) {
 927                         const char *p;
 928                         char *c;
 929
 930                         p = startswith(path, "/dev/");
 931                         c = strdup(p ?: path);
 932                         if (!c)
 933                                 return -ENOMEM;
 934
 935                         *ret = c;
 936                         return 0;
 937                 }
 938
 939                 if (r != ERANGE)
 940                         return -r;
 941
 942                 l *= 2;
 943         }
 944
 945         return 0;
 946 }
 947
 948 int getttyname_harder(int fd, char **r) {
 949         int k;
 950         char *s = NULL;
 951
 952         k = getttyname_malloc(fd, &s);
 953         if (k < 0)
 954                 return k;
 955
 956         if (streq(s, "tty")) {
 957                 free(s);
 958                 return get_ctty(0, NULL, r);
 959         }
 960
 961         *r = s;
 962         return 0;
 963 }
 964
 965 int get_ctty_devnr(pid_t pid, dev_t *d) {
 966         int r;
 967         _cleanup_free_ char *line = NULL;
 968         const char *p;
 969         unsigned long ttynr;
 970
 971         assert(pid >= 0);
 972
 973         p = procfs_file_alloca(pid, "stat");
 974         r = read_one_line_file(p, &line);
 975         if (r < 0)
 976                 return r;
 977
 978         p = strrchr(line, ')');
 979         if (!p)
 980                 return -EIO;
 981
 982         p++;
 983
 984         if (sscanf(p, " "
 985                    "%*c "  /* state */
 986                    "%*d "  /* ppid */
 987                    "%*d "  /* pgrp */
 988                    "%*d "  /* session */
 989                    "%lu ", /* ttynr */
 990                    &ttynr) != 1)
 991                 return -EIO;
 992
 993         if (major(ttynr) == 0 && minor(ttynr) == 0)
 994                 return -ENXIO;
 995
 996         if (d)
 997                 *d = (dev_t) ttynr;
 998
 999         return 0;
1000 }
1001
1002 int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
1003         char fn[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL;
1004         _cleanup_free_ char *s = NULL;
1005         const char *p;
1006         dev_t devnr;
1007         int k;
1008
1009         assert(r);
1010
1011         k = get_ctty_devnr(pid, &devnr);
1012         if (k < 0)
1013                 return k;
1014
1015         sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr));
1016
1017         k = readlink_malloc(fn, &s);
1018         if (k < 0) {
1019
1020                 if (k != -ENOENT)
1021                         return k;
1022
1023                 /* This is an ugly hack */
1024                 if (major(devnr) == 136) {
1025                         if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
1026                                 return -ENOMEM;
1027                 } else {
1028                         /* Probably something like the ptys which have no
1029                          * symlink in /dev/char. Let's return something
1030                          * vaguely useful. */
1031
1032                         b = strdup(fn + 5);
1033                         if (!b)
1034                                 return -ENOMEM;
1035                 }
1036         } else {
1037                 if (startswith(s, "/dev/"))
1038                         p = s + 5;
1039                 else if (startswith(s, "../"))
1040                         p = s + 3;
1041                 else
1042                         p = s;
1043
1044                 b = strdup(p);
1045                 if (!b)
1046                         return -ENOMEM;
1047         }
1048
1049         *r = b;
1050         if (_devnr)
1051                 *_devnr = devnr;
1052
1053         return 0;
1054 }
1055
1056 int ptsname_malloc(int fd, char **ret) {
1057         size_t l = 100;
1058
1059         assert(fd >= 0);
1060         assert(ret);
1061
1062         for (;;) {
1063                 char *c;
1064
1065                 c = new(char, l);
1066                 if (!c)
1067                         return -ENOMEM;
1068
1069                 if (ptsname_r(fd, c, l) == 0) {
1070                         *ret = c;
1071                         return 0;
1072                 }
1073                 if (errno != ERANGE) {
1074                         free(c);
1075                         return -errno;
1076                 }
1077
1078                 free(c);
1079                 l *= 2;
1080         }
1081 }
1082
1083 int ptsname_namespace(int pty, char **ret) {
1084         int no = -1, r;
1085
1086         /* Like ptsname(), but doesn't assume that the path is
1087          * accessible in the local namespace. */
1088
1089         r = ioctl(pty, TIOCGPTN, &no);
1090         if (r < 0)
1091                 return -errno;
1092
1093         if (no < 0)
1094                 return -EIO;
1095
1096         if (asprintf(ret, "/dev/pts/%i", no) < 0)
1097                 return -ENOMEM;
1098
1099         return 0;
1100 }
1101
1102 int openpt_in_namespace(pid_t pid, int flags) {
1103         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1104         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1105         siginfo_t si;
1106         pid_t child;
1107         int r;
1108
1109         assert(pid > 0);
1110
1111         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1112         if (r < 0)
1113                 return r;
1114
1115         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1116                 return -errno;
1117
1118         child = fork();
1119         if (child < 0)
1120                 return -errno;
1121
1122         if (child == 0) {
1123                 int master;
1124
1125                 pair[0] = safe_close(pair[0]);
1126
1127                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1128                 if (r < 0)
1129                         _exit(EXIT_FAILURE);
1130
1131                 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1132                 if (master < 0)
1133                         _exit(EXIT_FAILURE);
1134
1135                 if (unlockpt(master) < 0)
1136                         _exit(EXIT_FAILURE);
1137
1138                 if (send_one_fd(pair[1], master, 0) < 0)
1139                         _exit(EXIT_FAILURE);
1140
1141                 _exit(EXIT_SUCCESS);
1142         }
1143
1144         pair[1] = safe_close(pair[1]);
1145
1146         r = wait_for_terminate(child, &si);
1147         if (r < 0)
1148                 return r;
1149         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1150                 return -EIO;
1151
1152         return receive_one_fd(pair[0], 0);
1153 }
1154
1155 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1156         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1157         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1158         siginfo_t si;
1159         pid_t child;
1160         int r;
1161
1162         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1163         if (r < 0)
1164                 return r;
1165
1166         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1167                 return -errno;
1168
1169         child = fork();
1170         if (child < 0)
1171                 return -errno;
1172
1173         if (child == 0) {
1174                 int master;
1175
1176                 pair[0] = safe_close(pair[0]);
1177
1178                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1179                 if (r < 0)
1180                         _exit(EXIT_FAILURE);
1181
1182                 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1183                 if (master < 0)
1184                         _exit(EXIT_FAILURE);
1185
1186                 if (send_one_fd(pair[1], master, 0) < 0)
1187                         _exit(EXIT_FAILURE);
1188
1189                 _exit(EXIT_SUCCESS);
1190         }
1191
1192         pair[1] = safe_close(pair[1]);
1193
1194         r = wait_for_terminate(child, &si);
1195         if (r < 0)
1196                 return r;
1197         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1198                 return -EIO;
1199
1200         return receive_one_fd(pair[0], 0);
1201 }