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 <errno.h>
  21 #include <fcntl.h>
  22 #include <limits.h>
  23 #include <stdarg.h>
  24 #include <stddef.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <sys/inotify.h>
  28 #include <sys/socket.h>
  29 #include <sys/sysmacros.h>
  30 #include <sys/time.h>
  31 #include <linux/kd.h>
  32 #include <linux/tiocl.h>
  33 #include <linux/vt.h>
  34 #include <poll.h>
  35 #include <signal.h>
  36 #include <sys/ioctl.h>
  37 #include <sys/types.h>
  38 #include <termios.h>
  39 #include <unistd.h>
  40
  41 #include "alloc-util.h"
  42 #include "env-util.h"
  43 #include "fd-util.h"
  44 #include "fileio.h"
  45 #include "fs-util.h"
  46 #include "io-util.h"
  47 #include "log.h"
  48 #include "macro.h"
  49 #include "parse-util.h"
  50 #include "process-util.h"
  51 #include "socket-util.h"
  52 #include "stat-util.h"
  53 #include "string-util.h"
  54 #include "strv.h"
  55 #include "terminal-util.h"
  56 #include "time-util.h"
  57 #include "util.h"
  58 #include "path-util.h"
  59
  60 static volatile unsigned cached_columns = 0;
  61 static volatile unsigned cached_lines = 0;
  62
  63 int chvt(int vt) {
  64         _cleanup_close_ int fd;
  65
  66         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
  67         if (fd < 0)
  68                 return -errno;
  69
  70         if (vt <= 0) {
  71                 int tiocl[2] = {
  72                         TIOCL_GETKMSGREDIRECT,
  73                         0
  74                 };
  75
  76                 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
  77                         return -errno;
  78
  79                 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
  80         }
  81
  82         if (ioctl(fd, VT_ACTIVATE, vt) < 0)
  83                 return -errno;
  84
  85         return 0;
  86 }
  87
  88 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
  89         struct termios old_termios, new_termios;
  90         char c, line[LINE_MAX];
  91
  92         assert(f);
  93         assert(ret);
  94
  95         if (tcgetattr(fileno(f), &old_termios) >= 0) {
  96                 new_termios = old_termios;
  97
  98                 new_termios.c_lflag &= ~ICANON;
  99                 new_termios.c_cc[VMIN] = 1;
 100                 new_termios.c_cc[VTIME] = 0;
 101
 102                 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
 103                         size_t k;
 104
 105                         if (t != USEC_INFINITY) {
 106                                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
 107                                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 108                                         return -ETIMEDOUT;
 109                                 }
 110                         }
 111
 112                         k = fread(&c, 1, 1, f);
 113
 114                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 115
 116                         if (k <= 0)
 117                                 return -EIO;
 118
 119                         if (need_nl)
 120                                 *need_nl = c != '\n';
 121
 122                         *ret = c;
 123                         return 0;
 124                 }
 125         }
 126
 127         if (t != USEC_INFINITY) {
 128                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
 129                         return -ETIMEDOUT;
 130         }
 131
 132         errno = 0;
 133         if (!fgets(line, sizeof(line), f))
 134                 return errno > 0 ? -errno : -EIO;
 135
 136         truncate_nl(line);
 137
 138         if (strlen(line) != 1)
 139                 return -EBADMSG;
 140
 141         if (need_nl)
 142                 *need_nl = false;
 143
 144         *ret = line[0];
 145         return 0;
 146 }
 147
 148 #define DEFAULT_ASK_REFRESH_USEC (2*USEC_PER_SEC)
 149
 150 int ask_char(char *ret, const char *replies, const char *fmt, ...) {
 151         int r;
 152
 153         assert(ret);
 154         assert(replies);
 155         assert(fmt);
 156
 157         for (;;) {
 158                 va_list ap;
 159                 char c;
 160                 bool need_nl = true;
 161
 162                 if (colors_enabled())
 163                         fputs(ANSI_HIGHLIGHT, stdout);
 164
 165                 putchar('\r');
 166
 167                 va_start(ap, fmt);
 168                 vprintf(fmt, ap);
 169                 va_end(ap);
 170
 171                 if (colors_enabled())
 172                         fputs(ANSI_NORMAL, stdout);
 173
 174                 fflush(stdout);
 175
 176                 r = read_one_char(stdin, &c, DEFAULT_ASK_REFRESH_USEC, &need_nl);
 177                 if (r < 0) {
 178
 179                         if (r == -ETIMEDOUT)
 180                                 continue;
 181
 182                         if (r == -EBADMSG) {
 183                                 puts("Bad input, please try again.");
 184                                 continue;
 185                         }
 186
 187                         putchar('\n');
 188                         return r;
 189                 }
 190
 191                 if (need_nl)
 192                         putchar('\n');
 193
 194                 if (strchr(replies, c)) {
 195                         *ret = c;
 196                         return 0;
 197                 }
 198
 199                 puts("Read unexpected character, please try again.");
 200         }
 201 }
 202
 203 int ask_string(char **ret, const char *text, ...) {
 204         assert(ret);
 205         assert(text);
 206
 207         for (;;) {
 208                 char line[LINE_MAX];
 209                 va_list ap;
 210
 211                 if (colors_enabled())
 212                         fputs(ANSI_HIGHLIGHT, stdout);
 213
 214                 va_start(ap, text);
 215                 vprintf(text, ap);
 216                 va_end(ap);
 217
 218                 if (colors_enabled())
 219                         fputs(ANSI_NORMAL, stdout);
 220
 221                 fflush(stdout);
 222
 223                 errno = 0;
 224                 if (!fgets(line, sizeof(line), stdin))
 225                         return errno > 0 ? -errno : -EIO;
 226
 227                 if (!endswith(line, "\n"))
 228                         putchar('\n');
 229                 else {
 230                         char *s;
 231
 232                         if (isempty(line))
 233                                 continue;
 234
 235                         truncate_nl(line);
 236                         s = strdup(line);
 237                         if (!s)
 238                                 return -ENOMEM;
 239
 240                         *ret = s;
 241                         return 0;
 242                 }
 243         }
 244 }
 245
 246 int reset_terminal_fd(int fd, bool switch_to_text) {
 247         struct termios termios;
 248         _cleanup_free_ char *utf8 = NULL;
 249         int r = 0;
 250
 251         /* Set terminal to some sane defaults */
 252
 253         assert(fd >= 0);
 254
 255         /* We leave locked terminal attributes untouched, so that
 256          * Plymouth may set whatever it wants to set, and we don't
 257          * interfere with that. */
 258
 259         /* Disable exclusive mode, just in case */
 260         (void) ioctl(fd, TIOCNXCL);
 261
 262         /* Switch to text mode */
 263         if (switch_to_text)
 264                 (void) ioctl(fd, KDSETMODE, KD_TEXT);
 265
 266         /* Set default keyboard mode */
 267         (void) vt_reset_keyboard(fd);
 268
 269         if (tcgetattr(fd, &termios) < 0) {
 270                 r = -errno;
 271                 goto finish;
 272         }
 273
 274         /* We only reset the stuff that matters to the software. How
 275          * hardware is set up we don't touch assuming that somebody
 276          * else will do that for us */
 277
 278         termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
 279         termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
 280         termios.c_oflag |= ONLCR;
 281         termios.c_cflag |= CREAD;
 282         termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
 283
 284         termios.c_cc[VINTR]    =   03;  /* ^C */
 285         termios.c_cc[VQUIT]    =  034;  /* ^\ */
 286         termios.c_cc[VERASE]   = 0177;
 287         termios.c_cc[VKILL]    =  025;  /* ^X */
 288         termios.c_cc[VEOF]     =   04;  /* ^D */
 289         termios.c_cc[VSTART]   =  021;  /* ^Q */
 290         termios.c_cc[VSTOP]    =  023;  /* ^S */
 291         termios.c_cc[VSUSP]    =  032;  /* ^Z */
 292         termios.c_cc[VLNEXT]   =  026;  /* ^V */
 293         termios.c_cc[VWERASE]  =  027;  /* ^W */
 294         termios.c_cc[VREPRINT] =  022;  /* ^R */
 295         termios.c_cc[VEOL]     =    0;
 296         termios.c_cc[VEOL2]    =    0;
 297
 298         termios.c_cc[VTIME]  = 0;
 299         termios.c_cc[VMIN]   = 1;
 300
 301         if (tcsetattr(fd, TCSANOW, &termios) < 0)
 302                 r = -errno;
 303
 304 finish:
 305         /* Just in case, flush all crap out */
 306         (void) tcflush(fd, TCIOFLUSH);
 307
 308         return r;
 309 }
 310
 311 int reset_terminal(const char *name) {
 312         _cleanup_close_ int fd = -1;
 313
 314         /* We open the terminal with O_NONBLOCK here, to ensure we
 315          * don't block on carrier if this is a terminal with carrier
 316          * configured. */
 317
 318         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 319         if (fd < 0)
 320                 return fd;
 321
 322         return reset_terminal_fd(fd, true);
 323 }
 324
 325 int open_terminal(const char *name, int mode) {
 326         int fd, r;
 327         unsigned c = 0;
 328
 329         /*
 330          * If a TTY is in the process of being closed opening it might
 331          * cause EIO. This is horribly awful, but unlikely to be
 332          * changed in the kernel. Hence we work around this problem by
 333          * retrying a couple of times.
 334          *
 335          * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
 336          */
 337
 338         if (mode & O_CREAT)
 339                 return -EINVAL;
 340
 341         for (;;) {
 342                 fd = open(name, mode, 0);
 343                 if (fd >= 0)
 344                         break;
 345
 346                 if (errno != EIO)
 347                         return -errno;
 348
 349                 /* Max 1s in total */
 350                 if (c >= 20)
 351                         return -errno;
 352
 353                 usleep(50 * USEC_PER_MSEC);
 354                 c++;
 355         }
 356
 357         r = isatty(fd);
 358         if (r == 0) {
 359                 safe_close(fd);
 360                 return -ENOTTY;
 361         }
 362
 363         return fd;
 364 }
 365
 366 int acquire_terminal(
 367                 const char *name,
 368                 bool fail,
 369                 bool force,
 370                 bool ignore_tiocstty_eperm,
 371                 usec_t timeout) {
 372
 373         int fd = -1, notify = -1, r = 0, wd = -1;
 374         usec_t ts = 0;
 375
 376         assert(name);
 377
 378         /* We use inotify to be notified when the tty is closed. We
 379          * create the watch before checking if we can actually acquire
 380          * it, so that we don't lose any event.
 381          *
 382          * Note: strictly speaking this actually watches for the
 383          * device being closed, it does *not* really watch whether a
 384          * tty loses its controlling process. However, unless some
 385          * rogue process uses TIOCNOTTY on /dev/tty *after* closing
 386          * its tty otherwise this will not become a problem. As long
 387          * as the administrator makes sure not configure any service
 388          * on the same tty as an untrusted user this should not be a
 389          * problem. (Which he probably should not do anyway.) */
 390
 391         if (timeout != USEC_INFINITY)
 392                 ts = now(CLOCK_MONOTONIC);
 393
 394         if (!fail && !force) {
 395                 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
 396                 if (notify < 0) {
 397                         r = -errno;
 398                         goto fail;
 399                 }
 400
 401                 wd = inotify_add_watch(notify, name, IN_CLOSE);
 402                 if (wd < 0) {
 403                         r = -errno;
 404                         goto fail;
 405                 }
 406         }
 407
 408         for (;;) {
 409                 struct sigaction sa_old, sa_new = {
 410                         .sa_handler = SIG_IGN,
 411                         .sa_flags = SA_RESTART,
 412                 };
 413
 414                 if (notify >= 0) {
 415                         r = flush_fd(notify);
 416                         if (r < 0)
 417                                 goto fail;
 418                 }
 419
 420                 /* We pass here O_NOCTTY only so that we can check the return
 421                  * value TIOCSCTTY and have a reliable way to figure out if we
 422                  * successfully became the controlling process of the tty */
 423                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 424                 if (fd < 0)
 425                         return fd;
 426
 427                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 428                  * if we already own the tty. */
 429                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 430
 431                 /* First, try to get the tty */
 432                 if (ioctl(fd, TIOCSCTTY, force) < 0)
 433                         r = -errno;
 434
 435                 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 436
 437                 /* Sometimes, it makes sense to ignore TIOCSCTTY
 438                  * returning EPERM, i.e. when very likely we already
 439                  * are have this controlling terminal. */
 440                 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
 441                         r = 0;
 442
 443                 if (r < 0 && (force || fail || r != -EPERM))
 444                         goto fail;
 445
 446                 if (r >= 0)
 447                         break;
 448
 449                 assert(!fail);
 450                 assert(!force);
 451                 assert(notify >= 0);
 452
 453                 for (;;) {
 454                         union inotify_event_buffer buffer;
 455                         struct inotify_event *e;
 456                         ssize_t l;
 457
 458                         if (timeout != USEC_INFINITY) {
 459                                 usec_t n;
 460
 461                                 n = now(CLOCK_MONOTONIC);
 462                                 if (ts + timeout < n) {
 463                                         r = -ETIMEDOUT;
 464                                         goto fail;
 465                                 }
 466
 467                                 r = fd_wait_for_event(notify, POLLIN, ts + timeout - n);
 468                                 if (r < 0)
 469                                         goto fail;
 470
 471                                 if (r == 0) {
 472                                         r = -ETIMEDOUT;
 473                                         goto fail;
 474                                 }
 475                         }
 476
 477                         l = read(notify, &buffer, sizeof(buffer));
 478                         if (l < 0) {
 479                                 if (errno == EINTR || errno == EAGAIN)
 480                                         continue;
 481
 482                                 r = -errno;
 483                                 goto fail;
 484                         }
 485
 486                         FOREACH_INOTIFY_EVENT(e, buffer, l) {
 487                                 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
 488                                         r = -EIO;
 489                                         goto fail;
 490                                 }
 491                         }
 492
 493                         break;
 494                 }
 495
 496                 /* We close the tty fd here since if the old session
 497                  * ended our handle will be dead. It's important that
 498                  * we do this after sleeping, so that we don't enter
 499                  * an endless loop. */
 500                 fd = safe_close(fd);
 501         }
 502
 503         safe_close(notify);
 504
 505         return fd;
 506
 507 fail:
 508         safe_close(fd);
 509         safe_close(notify);
 510
 511         return r;
 512 }
 513
 514 int release_terminal(void) {
 515         static const struct sigaction sa_new = {
 516                 .sa_handler = SIG_IGN,
 517                 .sa_flags = SA_RESTART,
 518         };
 519
 520         _cleanup_close_ int fd = -1;
 521         struct sigaction sa_old;
 522         int r = 0;
 523
 524         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 525         if (fd < 0)
 526                 return -errno;
 527
 528         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 529          * by our own TIOCNOTTY */
 530         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 531
 532         if (ioctl(fd, TIOCNOTTY) < 0)
 533                 r = -errno;
 534
 535         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 536
 537         return r;
 538 }
 539
 540 int terminal_vhangup_fd(int fd) {
 541         assert(fd >= 0);
 542
 543         if (ioctl(fd, TIOCVHANGUP) < 0)
 544                 return -errno;
 545
 546         return 0;
 547 }
 548
 549 int terminal_vhangup(const char *name) {
 550         _cleanup_close_ int fd;
 551
 552         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 553         if (fd < 0)
 554                 return fd;
 555
 556         return terminal_vhangup_fd(fd);
 557 }
 558
 559 int vt_disallocate(const char *name) {
 560         _cleanup_close_ int fd = -1;
 561         const char *e, *n;
 562         unsigned u;
 563         int r;
 564
 565         /* Deallocate the VT if possible. If not possible
 566          * (i.e. because it is the active one), at least clear it
 567          * entirely (including the scrollback buffer) */
 568
 569         e = path_startswith(name, "/dev/");
 570         if (!e)
 571                 return -EINVAL;
 572
 573         if (!tty_is_vc(name)) {
 574                 /* So this is not a VT. I guess we cannot deallocate
 575                  * it then. But let's at least clear the screen */
 576
 577                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 578                 if (fd < 0)
 579                         return fd;
 580
 581                 loop_write(fd,
 582                            "\033[r"    /* clear scrolling region */
 583                            "\033[H"    /* move home */
 584                            "\033[2J",  /* clear screen */
 585                            10, false);
 586                 return 0;
 587         }
 588
 589         n = startswith(e, "tty");
 590         if (!n)
 591                 return -EINVAL;
 592
 593         r = safe_atou(n, &u);
 594         if (r < 0)
 595                 return r;
 596
 597         if (u <= 0)
 598                 return -EINVAL;
 599
 600         /* Try to deallocate */
 601         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 602         if (fd < 0)
 603                 return fd;
 604
 605         r = ioctl(fd, VT_DISALLOCATE, u);
 606         fd = safe_close(fd);
 607
 608         if (r >= 0)
 609                 return 0;
 610
 611         if (errno != EBUSY)
 612                 return -errno;
 613
 614         /* Couldn't deallocate, so let's clear it fully with
 615          * scrollback */
 616         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 617         if (fd < 0)
 618                 return fd;
 619
 620         loop_write(fd,
 621                    "\033[r"   /* clear scrolling region */
 622                    "\033[H"   /* move home */
 623                    "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
 624                    10, false);
 625         return 0;
 626 }
 627
 628 int make_console_stdio(void) {
 629         int fd, r;
 630
 631         /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
 632
 633         fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
 634         if (fd < 0)
 635                 return log_error_errno(fd, "Failed to acquire terminal: %m");
 636
 637         r = reset_terminal_fd(fd, true);
 638         if (r < 0)
 639                 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
 640
 641         r = make_stdio(fd);
 642         if (r < 0)
 643                 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
 644
 645         return 0;
 646 }
 647
 648 bool tty_is_vc(const char *tty) {
 649         assert(tty);
 650
 651         return vtnr_from_tty(tty) >= 0;
 652 }
 653
 654 bool tty_is_console(const char *tty) {
 655         assert(tty);
 656
 657         return streq(skip_dev_prefix(tty), "console");
 658 }
 659
 660 int vtnr_from_tty(const char *tty) {
 661         int i, r;
 662
 663         assert(tty);
 664
 665         tty = skip_dev_prefix(tty);
 666
 667         if (!startswith(tty, "tty") )
 668                 return -EINVAL;
 669
 670         if (tty[3] < '0' || tty[3] > '9')
 671                 return -EINVAL;
 672
 673         r = safe_atoi(tty+3, &i);
 674         if (r < 0)
 675                 return r;
 676
 677         if (i < 0 || i > 63)
 678                 return -EINVAL;
 679
 680         return i;
 681 }
 682
 683 char *resolve_dev_console(char **active) {
 684         char *tty;
 685
 686         /* Resolve where /dev/console is pointing to, if /sys is actually ours
 687          * (i.e. not read-only-mounted which is a sign for container setups) */
 688
 689         if (path_is_read_only_fs("/sys") > 0)
 690                 return NULL;
 691
 692         if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
 693                 return NULL;
 694
 695         /* If multiple log outputs are configured the last one is what
 696          * /dev/console points to */
 697         tty = strrchr(*active, ' ');
 698         if (tty)
 699                 tty++;
 700         else
 701                 tty = *active;
 702
 703         if (streq(tty, "tty0")) {
 704                 char *tmp;
 705
 706                 /* Get the active VC (e.g. tty1) */
 707                 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
 708                         free(*active);
 709                         tty = *active = tmp;
 710                 }
 711         }
 712
 713         return tty;
 714 }
 715
 716 int get_kernel_consoles(char ***consoles) {
 717         _cleanup_strv_free_ char **con = NULL;
 718         _cleanup_free_ char *line = NULL;
 719         const char *active;
 720         int r;
 721
 722         assert(consoles);
 723
 724         r = read_one_line_file("/sys/class/tty/console/active", &line);
 725         if (r < 0)
 726                 return r;
 727
 728         active = line;
 729         for (;;) {
 730                 _cleanup_free_ char *tty = NULL;
 731                 char *path;
 732
 733                 r = extract_first_word(&active, &tty, NULL, 0);
 734                 if (r < 0)
 735                         return r;
 736                 if (r == 0)
 737                         break;
 738
 739                 if (streq(tty, "tty0")) {
 740                         tty = mfree(tty);
 741                         r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
 742                         if (r < 0)
 743                                 return r;
 744                 }
 745
 746                 path = strappend("/dev/", tty);
 747                 if (!path)
 748                         return -ENOMEM;
 749
 750                 if (access(path, F_OK) < 0) {
 751                         log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
 752                         free(path);
 753                         continue;
 754                 }
 755
 756                 r = strv_consume(&con, path);
 757                 if (r < 0)
 758                         return r;
 759         }
 760
 761         if (strv_isempty(con)) {
 762                 log_debug("No devices found for system console");
 763
 764                 r = strv_extend(&con, "/dev/console");
 765                 if (r < 0)
 766                         return r;
 767         }
 768
 769         *consoles = con;
 770         con = NULL;
 771         return 0;
 772 }
 773
 774 bool tty_is_vc_resolve(const char *tty) {
 775         _cleanup_free_ char *active = NULL;
 776
 777         assert(tty);
 778
 779         tty = skip_dev_prefix(tty);
 780
 781         if (streq(tty, "console")) {
 782                 tty = resolve_dev_console(&active);
 783                 if (!tty)
 784                         return false;
 785         }
 786
 787         return tty_is_vc(tty);
 788 }
 789
 790 const char *default_term_for_tty(const char *tty) {
 791         return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220";
 792 }
 793
 794 int fd_columns(int fd) {
 795         struct winsize ws = {};
 796
 797         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 798                 return -errno;
 799
 800         if (ws.ws_col <= 0)
 801                 return -EIO;
 802
 803         return ws.ws_col;
 804 }
 805
 806 unsigned columns(void) {
 807         const char *e;
 808         int c;
 809
 810         if (_likely_(cached_columns > 0))
 811                 return cached_columns;
 812
 813         c = 0;
 814         e = getenv("COLUMNS");
 815         if (e)
 816                 (void) safe_atoi(e, &c);
 817
 818         if (c <= 0)
 819                 c = fd_columns(STDOUT_FILENO);
 820
 821         if (c <= 0)
 822                 c = 80;
 823
 824         cached_columns = c;
 825         return cached_columns;
 826 }
 827
 828 int fd_lines(int fd) {
 829         struct winsize ws = {};
 830
 831         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 832                 return -errno;
 833
 834         if (ws.ws_row <= 0)
 835                 return -EIO;
 836
 837         return ws.ws_row;
 838 }
 839
 840 unsigned lines(void) {
 841         const char *e;
 842         int l;
 843
 844         if (_likely_(cached_lines > 0))
 845                 return cached_lines;
 846
 847         l = 0;
 848         e = getenv("LINES");
 849         if (e)
 850                 (void) safe_atoi(e, &l);
 851
 852         if (l <= 0)
 853                 l = fd_lines(STDOUT_FILENO);
 854
 855         if (l <= 0)
 856                 l = 24;
 857
 858         cached_lines = l;
 859         return cached_lines;
 860 }
 861
 862 /* intended to be used as a SIGWINCH sighandler */
 863 void columns_lines_cache_reset(int signum) {
 864         cached_columns = 0;
 865         cached_lines = 0;
 866 }
 867
 868 bool on_tty(void) {
 869         static int cached_on_tty = -1;
 870
 871         if (_unlikely_(cached_on_tty < 0))
 872                 cached_on_tty = isatty(STDOUT_FILENO) > 0;
 873
 874         return cached_on_tty;
 875 }
 876
 877 int make_stdio(int fd) {
 878         int r, s, t;
 879
 880         assert(fd >= 0);
 881
 882         r = dup2(fd, STDIN_FILENO);
 883         s = dup2(fd, STDOUT_FILENO);
 884         t = dup2(fd, STDERR_FILENO);
 885
 886         if (fd >= 3)
 887                 safe_close(fd);
 888
 889         if (r < 0 || s < 0 || t < 0)
 890                 return -errno;
 891
 892         /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
 893          * dup2() was a NOP and the bit hence possibly set. */
 894         stdio_unset_cloexec();
 895
 896         return 0;
 897 }
 898
 899 int make_null_stdio(void) {
 900         int null_fd;
 901
 902         null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
 903         if (null_fd < 0)
 904                 return -errno;
 905
 906         return make_stdio(null_fd);
 907 }
 908
 909 int getttyname_malloc(int fd, char **ret) {
 910         size_t l = 100;
 911         int r;
 912
 913         assert(fd >= 0);
 914         assert(ret);
 915
 916         for (;;) {
 917                 char path[l];
 918
 919                 r = ttyname_r(fd, path, sizeof(path));
 920                 if (r == 0) {
 921                         char *c;
 922
 923                         c = strdup(skip_dev_prefix(path));
 924                         if (!c)
 925                                 return -ENOMEM;
 926
 927                         *ret = c;
 928                         return 0;
 929                 }
 930
 931                 if (r != ERANGE)
 932                         return -r;
 933
 934                 l *= 2;
 935         }
 936
 937         return 0;
 938 }
 939
 940 int getttyname_harder(int fd, char **r) {
 941         int k;
 942         char *s = NULL;
 943
 944         k = getttyname_malloc(fd, &s);
 945         if (k < 0)
 946                 return k;
 947
 948         if (streq(s, "tty")) {
 949                 free(s);
 950                 return get_ctty(0, NULL, r);
 951         }
 952
 953         *r = s;
 954         return 0;
 955 }
 956
 957 int get_ctty_devnr(pid_t pid, dev_t *d) {
 958         int r;
 959         _cleanup_free_ char *line = NULL;
 960         const char *p;
 961         unsigned long ttynr;
 962
 963         assert(pid >= 0);
 964
 965         p = procfs_file_alloca(pid, "stat");
 966         r = read_one_line_file(p, &line);
 967         if (r < 0)
 968                 return r;
 969
 970         p = strrchr(line, ')');
 971         if (!p)
 972                 return -EIO;
 973
 974         p++;
 975
 976         if (sscanf(p, " "
 977                    "%*c "  /* state */
 978                    "%*d "  /* ppid */
 979                    "%*d "  /* pgrp */
 980                    "%*d "  /* session */
 981                    "%lu ", /* ttynr */
 982                    &ttynr) != 1)
 983                 return -EIO;
 984
 985         if (major(ttynr) == 0 && minor(ttynr) == 0)
 986                 return -ENXIO;
 987
 988         if (d)
 989                 *d = (dev_t) ttynr;
 990
 991         return 0;
 992 }
 993
 994 int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
 995         char fn[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL;
 996         _cleanup_free_ char *s = NULL;
 997         const char *p;
 998         dev_t devnr;
 999         int k;
1000
1001         assert(r);
1002
1003         k = get_ctty_devnr(pid, &devnr);
1004         if (k < 0)
1005                 return k;
1006
1007         sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr));
1008
1009         k = readlink_malloc(fn, &s);
1010         if (k < 0) {
1011
1012                 if (k != -ENOENT)
1013                         return k;
1014
1015                 /* This is an ugly hack */
1016                 if (major(devnr) == 136) {
1017                         if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
1018                                 return -ENOMEM;
1019                 } else {
1020                         /* Probably something like the ptys which have no
1021                          * symlink in /dev/char. Let's return something
1022                          * vaguely useful. */
1023
1024                         b = strdup(fn + 5);
1025                         if (!b)
1026                                 return -ENOMEM;
1027                 }
1028         } else {
1029                 if (startswith(s, "/dev/"))
1030                         p = s + 5;
1031                 else if (startswith(s, "../"))
1032                         p = s + 3;
1033                 else
1034                         p = s;
1035
1036                 b = strdup(p);
1037                 if (!b)
1038                         return -ENOMEM;
1039         }
1040
1041         *r = b;
1042         if (_devnr)
1043                 *_devnr = devnr;
1044
1045         return 0;
1046 }
1047
1048 int ptsname_malloc(int fd, char **ret) {
1049         size_t l = 100;
1050
1051         assert(fd >= 0);
1052         assert(ret);
1053
1054         for (;;) {
1055                 char *c;
1056
1057                 c = new(char, l);
1058                 if (!c)
1059                         return -ENOMEM;
1060
1061                 if (ptsname_r(fd, c, l) == 0) {
1062                         *ret = c;
1063                         return 0;
1064                 }
1065                 if (errno != ERANGE) {
1066                         free(c);
1067                         return -errno;
1068                 }
1069
1070                 free(c);
1071                 l *= 2;
1072         }
1073 }
1074
1075 int ptsname_namespace(int pty, char **ret) {
1076         int no = -1, r;
1077
1078         /* Like ptsname(), but doesn't assume that the path is
1079          * accessible in the local namespace. */
1080
1081         r = ioctl(pty, TIOCGPTN, &no);
1082         if (r < 0)
1083                 return -errno;
1084
1085         if (no < 0)
1086                 return -EIO;
1087
1088         if (asprintf(ret, "/dev/pts/%i", no) < 0)
1089                 return -ENOMEM;
1090
1091         return 0;
1092 }
1093
1094 int openpt_in_namespace(pid_t pid, int flags) {
1095         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1096         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1097         siginfo_t si;
1098         pid_t child;
1099         int r;
1100
1101         assert(pid > 0);
1102
1103         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1104         if (r < 0)
1105                 return r;
1106
1107         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1108                 return -errno;
1109
1110         child = fork();
1111         if (child < 0)
1112                 return -errno;
1113
1114         if (child == 0) {
1115                 int master;
1116
1117                 pair[0] = safe_close(pair[0]);
1118
1119                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1120                 if (r < 0)
1121                         _exit(EXIT_FAILURE);
1122
1123                 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1124                 if (master < 0)
1125                         _exit(EXIT_FAILURE);
1126
1127                 if (unlockpt(master) < 0)
1128                         _exit(EXIT_FAILURE);
1129
1130                 if (send_one_fd(pair[1], master, 0) < 0)
1131                         _exit(EXIT_FAILURE);
1132
1133                 _exit(EXIT_SUCCESS);
1134         }
1135
1136         pair[1] = safe_close(pair[1]);
1137
1138         r = wait_for_terminate(child, &si);
1139         if (r < 0)
1140                 return r;
1141         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1142                 return -EIO;
1143
1144         return receive_one_fd(pair[0], 0);
1145 }
1146
1147 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1148         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1149         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1150         siginfo_t si;
1151         pid_t child;
1152         int r;
1153
1154         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1155         if (r < 0)
1156                 return r;
1157
1158         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1159                 return -errno;
1160
1161         child = fork();
1162         if (child < 0)
1163                 return -errno;
1164
1165         if (child == 0) {
1166                 int master;
1167
1168                 pair[0] = safe_close(pair[0]);
1169
1170                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1171                 if (r < 0)
1172                         _exit(EXIT_FAILURE);
1173
1174                 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1175                 if (master < 0)
1176                         _exit(EXIT_FAILURE);
1177
1178                 if (send_one_fd(pair[1], master, 0) < 0)
1179                         _exit(EXIT_FAILURE);
1180
1181                 _exit(EXIT_SUCCESS);
1182         }
1183
1184         pair[1] = safe_close(pair[1]);
1185
1186         r = wait_for_terminate(child, &si);
1187         if (r < 0)
1188                 return r;
1189         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1190                 return -EIO;
1191
1192         return receive_one_fd(pair[0], 0);
1193 }
1194
1195 static bool getenv_terminal_is_dumb(void) {
1196         const char *e;
1197
1198         e = getenv("TERM");
1199         if (!e)
1200                 return true;
1201
1202         return streq(e, "dumb");
1203 }
1204
1205 bool terminal_is_dumb(void) {
1206         if (!on_tty())
1207                 return true;
1208
1209         return getenv_terminal_is_dumb();
1210 }
1211
1212 bool colors_enabled(void) {
1213         static int enabled = -1;
1214
1215         if (_unlikely_(enabled < 0)) {
1216                 int val;
1217
1218                 val = getenv_bool("SYSTEMD_COLORS");
1219                 if (val >= 0)
1220                         enabled = val;
1221                 else if (getpid_cached() == 1)
1222                         /* PID1 outputs to the console without holding it open all the time */
1223                         enabled = !getenv_terminal_is_dumb();
1224                 else
1225                         enabled = !terminal_is_dumb();
1226         }
1227
1228         return enabled;
1229 }
1230
1231 bool underline_enabled(void) {
1232         static int enabled = -1;
1233
1234         if (enabled < 0) {
1235
1236                 /* The Linux console doesn't support underlining, turn it off, but only there. */
1237
1238                 if (!colors_enabled())
1239                         enabled = false;
1240                 else
1241                         enabled = !streq_ptr(getenv("TERM"), "linux");
1242         }
1243
1244         return enabled;
1245 }
1246
1247 int vt_default_utf8(void) {
1248         _cleanup_free_ char *b = NULL;
1249         int r;
1250
1251         /* Read the default VT UTF8 setting from the kernel */
1252
1253         r = read_one_line_file("/sys/module/vt/parameters/default_utf8", &b);
1254         if (r < 0)
1255                 return r;
1256
1257         return parse_boolean(b);
1258 }
1259
1260 int vt_reset_keyboard(int fd) {
1261         int kb;
1262
1263         /* If we can't read the default, then default to unicode. It's 2017 after all. */
1264         kb = vt_default_utf8() != 0 ? K_UNICODE : K_XLATE;
1265
1266         if (ioctl(fd, KDSKBMODE, kb) < 0)
1267                 return -errno;
1268
1269         return 0;
1270 }