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
  59 static volatile unsigned cached_columns = 0;
  60 static volatile unsigned cached_lines = 0;
  61
  62 int chvt(int vt) {
  63         _cleanup_close_ int fd;
  64
  65         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
  66         if (fd < 0)
  67                 return -errno;
  68
  69         if (vt <= 0) {
  70                 int tiocl[2] = {
  71                         TIOCL_GETKMSGREDIRECT,
  72                         0
  73                 };
  74
  75                 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
  76                         return -errno;
  77
  78                 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
  79         }
  80
  81         if (ioctl(fd, VT_ACTIVATE, vt) < 0)
  82                 return -errno;
  83
  84         return 0;
  85 }
  86
  87 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
  88         struct termios old_termios, new_termios;
  89         char c, line[LINE_MAX];
  90
  91         assert(f);
  92         assert(ret);
  93
  94         if (tcgetattr(fileno(f), &old_termios) >= 0) {
  95                 new_termios = old_termios;
  96
  97                 new_termios.c_lflag &= ~ICANON;
  98                 new_termios.c_cc[VMIN] = 1;
  99                 new_termios.c_cc[VTIME] = 0;
 100
 101                 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
 102                         size_t k;
 103
 104                         if (t != USEC_INFINITY) {
 105                                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
 106                                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 107                                         return -ETIMEDOUT;
 108                                 }
 109                         }
 110
 111                         k = fread(&c, 1, 1, f);
 112
 113                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 114
 115                         if (k <= 0)
 116                                 return -EIO;
 117
 118                         if (need_nl)
 119                                 *need_nl = c != '\n';
 120
 121                         *ret = c;
 122                         return 0;
 123                 }
 124         }
 125
 126         if (t != USEC_INFINITY) {
 127                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
 128                         return -ETIMEDOUT;
 129         }
 130
 131         errno = 0;
 132         if (!fgets(line, sizeof(line), f))
 133                 return errno > 0 ? -errno : -EIO;
 134
 135         truncate_nl(line);
 136
 137         if (strlen(line) != 1)
 138                 return -EBADMSG;
 139
 140         if (need_nl)
 141                 *need_nl = false;
 142
 143         *ret = line[0];
 144         return 0;
 145 }
 146
 147 int ask_char(char *ret, const char *replies, const char *text, ...) {
 148         int r;
 149
 150         assert(ret);
 151         assert(replies);
 152         assert(text);
 153
 154         for (;;) {
 155                 va_list ap;
 156                 char c;
 157                 bool need_nl = true;
 158
 159                 if (colors_enabled())
 160                         fputs(ANSI_HIGHLIGHT, stdout);
 161
 162                 va_start(ap, text);
 163                 vprintf(text, ap);
 164                 va_end(ap);
 165
 166                 if (colors_enabled())
 167                         fputs(ANSI_NORMAL, stdout);
 168
 169                 fflush(stdout);
 170
 171                 r = read_one_char(stdin, &c, USEC_INFINITY, &need_nl);
 172                 if (r < 0) {
 173
 174                         if (r == -EBADMSG) {
 175                                 puts("Bad input, please try again.");
 176                                 continue;
 177                         }
 178
 179                         putchar('\n');
 180                         return r;
 181                 }
 182
 183                 if (need_nl)
 184                         putchar('\n');
 185
 186                 if (strchr(replies, c)) {
 187                         *ret = c;
 188                         return 0;
 189                 }
 190
 191                 puts("Read unexpected character, please try again.");
 192         }
 193 }
 194
 195 int ask_string(char **ret, const char *text, ...) {
 196         assert(ret);
 197         assert(text);
 198
 199         for (;;) {
 200                 char line[LINE_MAX];
 201                 va_list ap;
 202
 203                 if (colors_enabled())
 204                         fputs(ANSI_HIGHLIGHT, stdout);
 205
 206                 va_start(ap, text);
 207                 vprintf(text, ap);
 208                 va_end(ap);
 209
 210                 if (colors_enabled())
 211                         fputs(ANSI_NORMAL, stdout);
 212
 213                 fflush(stdout);
 214
 215                 errno = 0;
 216                 if (!fgets(line, sizeof(line), stdin))
 217                         return errno > 0 ? -errno : -EIO;
 218
 219                 if (!endswith(line, "\n"))
 220                         putchar('\n');
 221                 else {
 222                         char *s;
 223
 224                         if (isempty(line))
 225                                 continue;
 226
 227                         truncate_nl(line);
 228                         s = strdup(line);
 229                         if (!s)
 230                                 return -ENOMEM;
 231
 232                         *ret = s;
 233                         return 0;
 234                 }
 235         }
 236 }
 237
 238 int reset_terminal_fd(int fd, bool switch_to_text) {
 239         struct termios termios;
 240         int r = 0;
 241
 242         /* Set terminal to some sane defaults */
 243
 244         assert(fd >= 0);
 245
 246         /* We leave locked terminal attributes untouched, so that
 247          * Plymouth may set whatever it wants to set, and we don't
 248          * interfere with that. */
 249
 250         /* Disable exclusive mode, just in case */
 251         (void) ioctl(fd, TIOCNXCL);
 252
 253         /* Switch to text mode */
 254         if (switch_to_text)
 255                 (void) ioctl(fd, KDSETMODE, KD_TEXT);
 256
 257         /* Enable console unicode mode */
 258         (void) ioctl(fd, KDSKBMODE, K_UNICODE);
 259
 260         if (tcgetattr(fd, &termios) < 0) {
 261                 r = -errno;
 262                 goto finish;
 263         }
 264
 265         /* We only reset the stuff that matters to the software. How
 266          * hardware is set up we don't touch assuming that somebody
 267          * else will do that for us */
 268
 269         termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
 270         termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
 271         termios.c_oflag |= ONLCR;
 272         termios.c_cflag |= CREAD;
 273         termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
 274
 275         termios.c_cc[VINTR]    =   03;  /* ^C */
 276         termios.c_cc[VQUIT]    =  034;  /* ^\ */
 277         termios.c_cc[VERASE]   = 0177;
 278         termios.c_cc[VKILL]    =  025;  /* ^X */
 279         termios.c_cc[VEOF]     =   04;  /* ^D */
 280         termios.c_cc[VSTART]   =  021;  /* ^Q */
 281         termios.c_cc[VSTOP]    =  023;  /* ^S */
 282         termios.c_cc[VSUSP]    =  032;  /* ^Z */
 283         termios.c_cc[VLNEXT]   =  026;  /* ^V */
 284         termios.c_cc[VWERASE]  =  027;  /* ^W */
 285         termios.c_cc[VREPRINT] =  022;  /* ^R */
 286         termios.c_cc[VEOL]     =    0;
 287         termios.c_cc[VEOL2]    =    0;
 288
 289         termios.c_cc[VTIME]  = 0;
 290         termios.c_cc[VMIN]   = 1;
 291
 292         if (tcsetattr(fd, TCSANOW, &termios) < 0)
 293                 r = -errno;
 294
 295 finish:
 296         /* Just in case, flush all crap out */
 297         (void) tcflush(fd, TCIOFLUSH);
 298
 299         return r;
 300 }
 301
 302 int reset_terminal(const char *name) {
 303         _cleanup_close_ int fd = -1;
 304
 305         /* We open the terminal with O_NONBLOCK here, to ensure we
 306          * don't block on carrier if this is a terminal with carrier
 307          * configured. */
 308
 309         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 310         if (fd < 0)
 311                 return fd;
 312
 313         return reset_terminal_fd(fd, true);
 314 }
 315
 316 int open_terminal(const char *name, int mode) {
 317         int fd, r;
 318         unsigned c = 0;
 319
 320         /*
 321          * If a TTY is in the process of being closed opening it might
 322          * cause EIO. This is horribly awful, but unlikely to be
 323          * changed in the kernel. Hence we work around this problem by
 324          * retrying a couple of times.
 325          *
 326          * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
 327          */
 328
 329         if (mode & O_CREAT)
 330                 return -EINVAL;
 331
 332         for (;;) {
 333                 fd = open(name, mode, 0);
 334                 if (fd >= 0)
 335                         break;
 336
 337                 if (errno != EIO)
 338                         return -errno;
 339
 340                 /* Max 1s in total */
 341                 if (c >= 20)
 342                         return -errno;
 343
 344                 usleep(50 * USEC_PER_MSEC);
 345                 c++;
 346         }
 347
 348         r = isatty(fd);
 349         if (r < 0) {
 350                 safe_close(fd);
 351                 return -errno;
 352         }
 353
 354         if (!r) {
 355                 safe_close(fd);
 356                 return -ENOTTY;
 357         }
 358
 359         return fd;
 360 }
 361
 362 int acquire_terminal(
 363                 const char *name,
 364                 bool fail,
 365                 bool force,
 366                 bool ignore_tiocstty_eperm,
 367                 usec_t timeout) {
 368
 369         int fd = -1, notify = -1, r = 0, wd = -1;
 370         usec_t ts = 0;
 371
 372         assert(name);
 373
 374         /* We use inotify to be notified when the tty is closed. We
 375          * create the watch before checking if we can actually acquire
 376          * it, so that we don't lose any event.
 377          *
 378          * Note: strictly speaking this actually watches for the
 379          * device being closed, it does *not* really watch whether a
 380          * tty loses its controlling process. However, unless some
 381          * rogue process uses TIOCNOTTY on /dev/tty *after* closing
 382          * its tty otherwise this will not become a problem. As long
 383          * as the administrator makes sure not configure any service
 384          * on the same tty as an untrusted user this should not be a
 385          * problem. (Which he probably should not do anyway.) */
 386
 387         if (timeout != USEC_INFINITY)
 388                 ts = now(CLOCK_MONOTONIC);
 389
 390         if (!fail && !force) {
 391                 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
 392                 if (notify < 0) {
 393                         r = -errno;
 394                         goto fail;
 395                 }
 396
 397                 wd = inotify_add_watch(notify, name, IN_CLOSE);
 398                 if (wd < 0) {
 399                         r = -errno;
 400                         goto fail;
 401                 }
 402         }
 403
 404         for (;;) {
 405                 struct sigaction sa_old, sa_new = {
 406                         .sa_handler = SIG_IGN,
 407                         .sa_flags = SA_RESTART,
 408                 };
 409
 410                 if (notify >= 0) {
 411                         r = flush_fd(notify);
 412                         if (r < 0)
 413                                 goto fail;
 414                 }
 415
 416                 /* We pass here O_NOCTTY only so that we can check the return
 417                  * value TIOCSCTTY and have a reliable way to figure out if we
 418                  * successfully became the controlling process of the tty */
 419                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 420                 if (fd < 0)
 421                         return fd;
 422
 423                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 424                  * if we already own the tty. */
 425                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 426
 427                 /* First, try to get the tty */
 428                 if (ioctl(fd, TIOCSCTTY, force) < 0)
 429                         r = -errno;
 430
 431                 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 432
 433                 /* Sometimes, it makes sense to ignore TIOCSCTTY
 434                  * returning EPERM, i.e. when very likely we already
 435                  * are have this controlling terminal. */
 436                 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
 437                         r = 0;
 438
 439                 if (r < 0 && (force || fail || r != -EPERM))
 440                         goto fail;
 441
 442                 if (r >= 0)
 443                         break;
 444
 445                 assert(!fail);
 446                 assert(!force);
 447                 assert(notify >= 0);
 448
 449                 for (;;) {
 450                         union inotify_event_buffer buffer;
 451                         struct inotify_event *e;
 452                         ssize_t l;
 453
 454                         if (timeout != USEC_INFINITY) {
 455                                 usec_t n;
 456
 457                                 n = now(CLOCK_MONOTONIC);
 458                                 if (ts + timeout < n) {
 459                                         r = -ETIMEDOUT;
 460                                         goto fail;
 461                                 }
 462
 463                                 r = fd_wait_for_event(fd, POLLIN, ts + timeout - n);
 464                                 if (r < 0)
 465                                         goto fail;
 466
 467                                 if (r == 0) {
 468                                         r = -ETIMEDOUT;
 469                                         goto fail;
 470                                 }
 471                         }
 472
 473                         l = read(notify, &buffer, sizeof(buffer));
 474                         if (l < 0) {
 475                                 if (errno == EINTR || errno == EAGAIN)
 476                                         continue;
 477
 478                                 r = -errno;
 479                                 goto fail;
 480                         }
 481
 482                         FOREACH_INOTIFY_EVENT(e, buffer, l) {
 483                                 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
 484                                         r = -EIO;
 485                                         goto fail;
 486                                 }
 487                         }
 488
 489                         break;
 490                 }
 491
 492                 /* We close the tty fd here since if the old session
 493                  * ended our handle will be dead. It's important that
 494                  * we do this after sleeping, so that we don't enter
 495                  * an endless loop. */
 496                 fd = safe_close(fd);
 497         }
 498
 499         safe_close(notify);
 500
 501         return fd;
 502
 503 fail:
 504         safe_close(fd);
 505         safe_close(notify);
 506
 507         return r;
 508 }
 509
 510 int release_terminal(void) {
 511         static const struct sigaction sa_new = {
 512                 .sa_handler = SIG_IGN,
 513                 .sa_flags = SA_RESTART,
 514         };
 515
 516         _cleanup_close_ int fd = -1;
 517         struct sigaction sa_old;
 518         int r = 0;
 519
 520         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 521         if (fd < 0)
 522                 return -errno;
 523
 524         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 525          * by our own TIOCNOTTY */
 526         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 527
 528         if (ioctl(fd, TIOCNOTTY) < 0)
 529                 r = -errno;
 530
 531         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 532
 533         return r;
 534 }
 535
 536 int terminal_vhangup_fd(int fd) {
 537         assert(fd >= 0);
 538
 539         if (ioctl(fd, TIOCVHANGUP) < 0)
 540                 return -errno;
 541
 542         return 0;
 543 }
 544
 545 int terminal_vhangup(const char *name) {
 546         _cleanup_close_ int fd;
 547
 548         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 549         if (fd < 0)
 550                 return fd;
 551
 552         return terminal_vhangup_fd(fd);
 553 }
 554
 555 int vt_disallocate(const char *name) {
 556         _cleanup_close_ int fd = -1;
 557         unsigned u;
 558         int r;
 559
 560         /* Deallocate the VT if possible. If not possible
 561          * (i.e. because it is the active one), at least clear it
 562          * entirely (including the scrollback buffer) */
 563
 564         if (!startswith(name, "/dev/"))
 565                 return -EINVAL;
 566
 567         if (!tty_is_vc(name)) {
 568                 /* So this is not a VT. I guess we cannot deallocate
 569                  * it then. But let's at least clear the screen */
 570
 571                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 572                 if (fd < 0)
 573                         return fd;
 574
 575                 loop_write(fd,
 576                            "\033[r"    /* clear scrolling region */
 577                            "\033[H"    /* move home */
 578                            "\033[2J",  /* clear screen */
 579                            10, false);
 580                 return 0;
 581         }
 582
 583         if (!startswith(name, "/dev/tty"))
 584                 return -EINVAL;
 585
 586         r = safe_atou(name+8, &u);
 587         if (r < 0)
 588                 return r;
 589
 590         if (u <= 0)
 591                 return -EINVAL;
 592
 593         /* Try to deallocate */
 594         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 595         if (fd < 0)
 596                 return fd;
 597
 598         r = ioctl(fd, VT_DISALLOCATE, u);
 599         fd = safe_close(fd);
 600
 601         if (r >= 0)
 602                 return 0;
 603
 604         if (errno != EBUSY)
 605                 return -errno;
 606
 607         /* Couldn't deallocate, so let's clear it fully with
 608          * scrollback */
 609         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 610         if (fd < 0)
 611                 return fd;
 612
 613         loop_write(fd,
 614                    "\033[r"   /* clear scrolling region */
 615                    "\033[H"   /* move home */
 616                    "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
 617                    10, false);
 618         return 0;
 619 }
 620
 621 int make_console_stdio(void) {
 622         int fd, r;
 623
 624         /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
 625
 626         fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
 627         if (fd < 0)
 628                 return log_error_errno(fd, "Failed to acquire terminal: %m");
 629
 630         r = reset_terminal_fd(fd, true);
 631         if (r < 0)
 632                 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
 633
 634         r = make_stdio(fd);
 635         if (r < 0)
 636                 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
 637
 638         return 0;
 639 }
 640
 641 bool tty_is_vc(const char *tty) {
 642         assert(tty);
 643
 644         return vtnr_from_tty(tty) >= 0;
 645 }
 646
 647 bool tty_is_console(const char *tty) {
 648         assert(tty);
 649
 650         if (startswith(tty, "/dev/"))
 651                 tty += 5;
 652
 653         return streq(tty, "console");
 654 }
 655
 656 int vtnr_from_tty(const char *tty) {
 657         int i, r;
 658
 659         assert(tty);
 660
 661         if (startswith(tty, "/dev/"))
 662                 tty += 5;
 663
 664         if (!startswith(tty, "tty") )
 665                 return -EINVAL;
 666
 667         if (tty[3] < '0' || tty[3] > '9')
 668                 return -EINVAL;
 669
 670         r = safe_atoi(tty+3, &i);
 671         if (r < 0)
 672                 return r;
 673
 674         if (i < 0 || i > 63)
 675                 return -EINVAL;
 676
 677         return i;
 678 }
 679
 680 char *resolve_dev_console(char **active) {
 681         char *tty;
 682
 683         /* Resolve where /dev/console is pointing to, if /sys is actually ours
 684          * (i.e. not read-only-mounted which is a sign for container setups) */
 685
 686         if (path_is_read_only_fs("/sys") > 0)
 687                 return NULL;
 688
 689         if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
 690                 return NULL;
 691
 692         /* If multiple log outputs are configured the last one is what
 693          * /dev/console points to */
 694         tty = strrchr(*active, ' ');
 695         if (tty)
 696                 tty++;
 697         else
 698                 tty = *active;
 699
 700         if (streq(tty, "tty0")) {
 701                 char *tmp;
 702
 703                 /* Get the active VC (e.g. tty1) */
 704                 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
 705                         free(*active);
 706                         tty = *active = tmp;
 707                 }
 708         }
 709
 710         return tty;
 711 }
 712
 713 int get_kernel_consoles(char ***consoles) {
 714         _cleanup_strv_free_ char **con = NULL;
 715         _cleanup_free_ char *line = NULL;
 716         const char *active;
 717         int r;
 718
 719         assert(consoles);
 720
 721         r = read_one_line_file("/sys/class/tty/console/active", &line);
 722         if (r < 0)
 723                 return r;
 724
 725         active = line;
 726         for (;;) {
 727                 _cleanup_free_ char *tty = NULL;
 728                 char *path;
 729
 730                 r = extract_first_word(&active, &tty, NULL, 0);
 731                 if (r < 0)
 732                         return r;
 733                 if (r == 0)
 734                         break;
 735
 736                 if (streq(tty, "tty0")) {
 737                         tty = mfree(tty);
 738                         r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
 739                         if (r < 0)
 740                                 return r;
 741                 }
 742
 743                 path = strappend("/dev/", tty);
 744                 if (!path)
 745                         return -ENOMEM;
 746
 747                 if (access(path, F_OK) < 0) {
 748                         log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
 749                         free(path);
 750                         continue;
 751                 }
 752
 753                 r = strv_consume(&con, path);
 754                 if (r < 0)
 755                         return r;
 756         }
 757
 758         if (strv_isempty(con)) {
 759                 log_debug("No devices found for system console");
 760
 761                 r = strv_extend(&con, "/dev/console");
 762                 if (r < 0)
 763                         return r;
 764         }
 765
 766         *consoles = con;
 767         con = NULL;
 768         return 0;
 769 }
 770
 771 bool tty_is_vc_resolve(const char *tty) {
 772         _cleanup_free_ char *active = NULL;
 773
 774         assert(tty);
 775
 776         if (startswith(tty, "/dev/"))
 777                 tty += 5;
 778
 779         if (streq(tty, "console")) {
 780                 tty = resolve_dev_console(&active);
 781                 if (!tty)
 782                         return false;
 783         }
 784
 785         return tty_is_vc(tty);
 786 }
 787
 788 const char *default_term_for_tty(const char *tty) {
 789         return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220";
 790 }
 791
 792 int fd_columns(int fd) {
 793         struct winsize ws = {};
 794
 795         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 796                 return -errno;
 797
 798         if (ws.ws_col <= 0)
 799                 return -EIO;
 800
 801         return ws.ws_col;
 802 }
 803
 804 unsigned columns(void) {
 805         const char *e;
 806         int c;
 807
 808         if (_likely_(cached_columns > 0))
 809                 return cached_columns;
 810
 811         c = 0;
 812         e = getenv("COLUMNS");
 813         if (e)
 814                 (void) safe_atoi(e, &c);
 815
 816         if (c <= 0)
 817                 c = fd_columns(STDOUT_FILENO);
 818
 819         if (c <= 0)
 820                 c = 80;
 821
 822         cached_columns = c;
 823         return cached_columns;
 824 }
 825
 826 int fd_lines(int fd) {
 827         struct winsize ws = {};
 828
 829         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 830                 return -errno;
 831
 832         if (ws.ws_row <= 0)
 833                 return -EIO;
 834
 835         return ws.ws_row;
 836 }
 837
 838 unsigned lines(void) {
 839         const char *e;
 840         int l;
 841
 842         if (_likely_(cached_lines > 0))
 843                 return cached_lines;
 844
 845         l = 0;
 846         e = getenv("LINES");
 847         if (e)
 848                 (void) safe_atoi(e, &l);
 849
 850         if (l <= 0)
 851                 l = fd_lines(STDOUT_FILENO);
 852
 853         if (l <= 0)
 854                 l = 24;
 855
 856         cached_lines = l;
 857         return cached_lines;
 858 }
 859
 860 /* intended to be used as a SIGWINCH sighandler */
 861 void columns_lines_cache_reset(int signum) {
 862         cached_columns = 0;
 863         cached_lines = 0;
 864 }
 865
 866 bool on_tty(void) {
 867         static int cached_on_tty = -1;
 868
 869         if (_unlikely_(cached_on_tty < 0))
 870                 cached_on_tty = isatty(STDOUT_FILENO) > 0;
 871
 872         return cached_on_tty;
 873 }
 874
 875 int make_stdio(int fd) {
 876         int r, s, t;
 877
 878         assert(fd >= 0);
 879
 880         r = dup2(fd, STDIN_FILENO);
 881         s = dup2(fd, STDOUT_FILENO);
 882         t = dup2(fd, STDERR_FILENO);
 883
 884         if (fd >= 3)
 885                 safe_close(fd);
 886
 887         if (r < 0 || s < 0 || t < 0)
 888                 return -errno;
 889
 890         /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
 891          * dup2() was a NOP and the bit hence possibly set. */
 892         stdio_unset_cloexec();
 893
 894         return 0;
 895 }
 896
 897 int make_null_stdio(void) {
 898         int null_fd;
 899
 900         null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
 901         if (null_fd < 0)
 902                 return -errno;
 903
 904         return make_stdio(null_fd);
 905 }
 906
 907 int getttyname_malloc(int fd, char **ret) {
 908         size_t l = 100;
 909         int r;
 910
 911         assert(fd >= 0);
 912         assert(ret);
 913
 914         for (;;) {
 915                 char path[l];
 916
 917                 r = ttyname_r(fd, path, sizeof(path));
 918                 if (r == 0) {
 919                         const char *p;
 920                         char *c;
 921
 922                         p = startswith(path, "/dev/");
 923                         c = strdup(p ?: 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() == 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 }