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