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 #define DEFAULT_ASK_REFRESH_USEC (2*USEC_PER_SEC)
 148
 149 int ask_char(char *ret, const char *replies, const char *fmt, ...) {
 150         int r;
 151
 152         assert(ret);
 153         assert(replies);
 154         assert(fmt);
 155
 156         for (;;) {
 157                 va_list ap;
 158                 char c;
 159                 bool need_nl = true;
 160
 161                 if (colors_enabled())
 162                         fputs(ANSI_HIGHLIGHT, stdout);
 163
 164                 putchar('\r');
 165
 166                 va_start(ap, fmt);
 167                 vprintf(fmt, ap);
 168                 va_end(ap);
 169
 170                 if (colors_enabled())
 171                         fputs(ANSI_NORMAL, stdout);
 172
 173                 fflush(stdout);
 174
 175                 r = read_one_char(stdin, &c, DEFAULT_ASK_REFRESH_USEC, &need_nl);
 176                 if (r < 0) {
 177
 178                         if (r == -ETIMEDOUT)
 179                                 continue;
 180
 181                         if (r == -EBADMSG) {
 182                                 puts("Bad input, please try again.");
 183                                 continue;
 184                         }
 185
 186                         putchar('\n');
 187                         return r;
 188                 }
 189
 190                 if (need_nl)
 191                         putchar('\n');
 192
 193                 if (strchr(replies, c)) {
 194                         *ret = c;
 195                         return 0;
 196                 }
 197
 198                 puts("Read unexpected character, please try again.");
 199         }
 200 }
 201
 202 int ask_string(char **ret, const char *text, ...) {
 203         assert(ret);
 204         assert(text);
 205
 206         for (;;) {
 207                 char line[LINE_MAX];
 208                 va_list ap;
 209
 210                 if (colors_enabled())
 211                         fputs(ANSI_HIGHLIGHT, stdout);
 212
 213                 va_start(ap, text);
 214                 vprintf(text, ap);
 215                 va_end(ap);
 216
 217                 if (colors_enabled())
 218                         fputs(ANSI_NORMAL, stdout);
 219
 220                 fflush(stdout);
 221
 222                 errno = 0;
 223                 if (!fgets(line, sizeof(line), stdin))
 224                         return errno > 0 ? -errno : -EIO;
 225
 226                 if (!endswith(line, "\n"))
 227                         putchar('\n');
 228                 else {
 229                         char *s;
 230
 231                         if (isempty(line))
 232                                 continue;
 233
 234                         truncate_nl(line);
 235                         s = strdup(line);
 236                         if (!s)
 237                                 return -ENOMEM;
 238
 239                         *ret = s;
 240                         return 0;
 241                 }
 242         }
 243 }
 244
 245 int reset_terminal_fd(int fd, bool switch_to_text) {
 246         struct termios termios;
 247         int r = 0;
 248
 249         /* Set terminal to some sane defaults */
 250
 251         assert(fd >= 0);
 252
 253         /* We leave locked terminal attributes untouched, so that
 254          * Plymouth may set whatever it wants to set, and we don't
 255          * interfere with that. */
 256
 257         /* Disable exclusive mode, just in case */
 258         (void) ioctl(fd, TIOCNXCL);
 259
 260         /* Switch to text mode */
 261         if (switch_to_text)
 262                 (void) ioctl(fd, KDSETMODE, KD_TEXT);
 263
 264         /* Enable console unicode mode */
 265         (void) ioctl(fd, KDSKBMODE, K_UNICODE);
 266
 267         if (tcgetattr(fd, &termios) < 0) {
 268                 r = -errno;
 269                 goto finish;
 270         }
 271
 272         /* We only reset the stuff that matters to the software. How
 273          * hardware is set up we don't touch assuming that somebody
 274          * else will do that for us */
 275
 276         termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
 277         termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
 278         termios.c_oflag |= ONLCR;
 279         termios.c_cflag |= CREAD;
 280         termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
 281
 282         termios.c_cc[VINTR]    =   03;  /* ^C */
 283         termios.c_cc[VQUIT]    =  034;  /* ^\ */
 284         termios.c_cc[VERASE]   = 0177;
 285         termios.c_cc[VKILL]    =  025;  /* ^X */
 286         termios.c_cc[VEOF]     =   04;  /* ^D */
 287         termios.c_cc[VSTART]   =  021;  /* ^Q */
 288         termios.c_cc[VSTOP]    =  023;  /* ^S */
 289         termios.c_cc[VSUSP]    =  032;  /* ^Z */
 290         termios.c_cc[VLNEXT]   =  026;  /* ^V */
 291         termios.c_cc[VWERASE]  =  027;  /* ^W */
 292         termios.c_cc[VREPRINT] =  022;  /* ^R */
 293         termios.c_cc[VEOL]     =    0;
 294         termios.c_cc[VEOL2]    =    0;
 295
 296         termios.c_cc[VTIME]  = 0;
 297         termios.c_cc[VMIN]   = 1;
 298
 299         if (tcsetattr(fd, TCSANOW, &termios) < 0)
 300                 r = -errno;
 301
 302 finish:
 303         /* Just in case, flush all crap out */
 304         (void) tcflush(fd, TCIOFLUSH);
 305
 306         return r;
 307 }
 308
 309 int reset_terminal(const char *name) {
 310         _cleanup_close_ int fd = -1;
 311
 312         /* We open the terminal with O_NONBLOCK here, to ensure we
 313          * don't block on carrier if this is a terminal with carrier
 314          * configured. */
 315
 316         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 317         if (fd < 0)
 318                 return fd;
 319
 320         return reset_terminal_fd(fd, true);
 321 }
 322
 323 int open_terminal(const char *name, int mode) {
 324         int fd, r;
 325         unsigned c = 0;
 326
 327         /*
 328          * If a TTY is in the process of being closed opening it might
 329          * cause EIO. This is horribly awful, but unlikely to be
 330          * changed in the kernel. Hence we work around this problem by
 331          * retrying a couple of times.
 332          *
 333          * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
 334          */
 335
 336         if (mode & O_CREAT)
 337                 return -EINVAL;
 338
 339         for (;;) {
 340                 fd = open(name, mode, 0);
 341                 if (fd >= 0)
 342                         break;
 343
 344                 if (errno != EIO)
 345                         return -errno;
 346
 347                 /* Max 1s in total */
 348                 if (c >= 20)
 349                         return -errno;
 350
 351                 usleep(50 * USEC_PER_MSEC);
 352                 c++;
 353         }
 354
 355         r = isatty(fd);
 356         if (r == 0) {
 357                 safe_close(fd);
 358                 return -ENOTTY;
 359         }
 360
 361         return fd;
 362 }
 363
 364 int acquire_terminal(
 365                 const char *name,
 366                 bool fail,
 367                 bool force,
 368                 bool ignore_tiocstty_eperm,
 369                 usec_t timeout) {
 370
 371         int fd = -1, notify = -1, r = 0, wd = -1;
 372         usec_t ts = 0;
 373
 374         assert(name);
 375
 376         /* We use inotify to be notified when the tty is closed. We
 377          * create the watch before checking if we can actually acquire
 378          * it, so that we don't lose any event.
 379          *
 380          * Note: strictly speaking this actually watches for the
 381          * device being closed, it does *not* really watch whether a
 382          * tty loses its controlling process. However, unless some
 383          * rogue process uses TIOCNOTTY on /dev/tty *after* closing
 384          * its tty otherwise this will not become a problem. As long
 385          * as the administrator makes sure not configure any service
 386          * on the same tty as an untrusted user this should not be a
 387          * problem. (Which he probably should not do anyway.) */
 388
 389         if (timeout != USEC_INFINITY)
 390                 ts = now(CLOCK_MONOTONIC);
 391
 392         if (!fail && !force) {
 393                 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
 394                 if (notify < 0) {
 395                         r = -errno;
 396                         goto fail;
 397                 }
 398
 399                 wd = inotify_add_watch(notify, name, IN_CLOSE);
 400                 if (wd < 0) {
 401                         r = -errno;
 402                         goto fail;
 403                 }
 404         }
 405
 406         for (;;) {
 407                 struct sigaction sa_old, sa_new = {
 408                         .sa_handler = SIG_IGN,
 409                         .sa_flags = SA_RESTART,
 410                 };
 411
 412                 if (notify >= 0) {
 413                         r = flush_fd(notify);
 414                         if (r < 0)
 415                                 goto fail;
 416                 }
 417
 418                 /* We pass here O_NOCTTY only so that we can check the return
 419                  * value TIOCSCTTY and have a reliable way to figure out if we
 420                  * successfully became the controlling process of the tty */
 421                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 422                 if (fd < 0)
 423                         return fd;
 424
 425                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 426                  * if we already own the tty. */
 427                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 428
 429                 /* First, try to get the tty */
 430                 if (ioctl(fd, TIOCSCTTY, force) < 0)
 431                         r = -errno;
 432
 433                 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 434
 435                 /* Sometimes, it makes sense to ignore TIOCSCTTY
 436                  * returning EPERM, i.e. when very likely we already
 437                  * are have this controlling terminal. */
 438                 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
 439                         r = 0;
 440
 441                 if (r < 0 && (force || fail || r != -EPERM))
 442                         goto fail;
 443
 444                 if (r >= 0)
 445                         break;
 446
 447                 assert(!fail);
 448                 assert(!force);
 449                 assert(notify >= 0);
 450
 451                 for (;;) {
 452                         union inotify_event_buffer buffer;
 453                         struct inotify_event *e;
 454                         ssize_t l;
 455
 456                         if (timeout != USEC_INFINITY) {
 457                                 usec_t n;
 458
 459                                 n = now(CLOCK_MONOTONIC);
 460                                 if (ts + timeout < n) {
 461                                         r = -ETIMEDOUT;
 462                                         goto fail;
 463                                 }
 464
 465                                 r = fd_wait_for_event(notify, POLLIN, ts + timeout - n);
 466                                 if (r < 0)
 467                                         goto fail;
 468
 469                                 if (r == 0) {
 470                                         r = -ETIMEDOUT;
 471                                         goto fail;
 472                                 }
 473                         }
 474
 475                         l = read(notify, &buffer, sizeof(buffer));
 476                         if (l < 0) {
 477                                 if (errno == EINTR || errno == EAGAIN)
 478                                         continue;
 479
 480                                 r = -errno;
 481                                 goto fail;
 482                         }
 483
 484                         FOREACH_INOTIFY_EVENT(e, buffer, l) {
 485                                 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
 486                                         r = -EIO;
 487                                         goto fail;
 488                                 }
 489                         }
 490
 491                         break;
 492                 }
 493
 494                 /* We close the tty fd here since if the old session
 495                  * ended our handle will be dead. It's important that
 496                  * we do this after sleeping, so that we don't enter
 497                  * an endless loop. */
 498                 fd = safe_close(fd);
 499         }
 500
 501         safe_close(notify);
 502
 503         return fd;
 504
 505 fail:
 506         safe_close(fd);
 507         safe_close(notify);
 508
 509         return r;
 510 }
 511
 512 int release_terminal(void) {
 513         static const struct sigaction sa_new = {
 514                 .sa_handler = SIG_IGN,
 515                 .sa_flags = SA_RESTART,
 516         };
 517
 518         _cleanup_close_ int fd = -1;
 519         struct sigaction sa_old;
 520         int r = 0;
 521
 522         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 523         if (fd < 0)
 524                 return -errno;
 525
 526         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 527          * by our own TIOCNOTTY */
 528         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 529
 530         if (ioctl(fd, TIOCNOTTY) < 0)
 531                 r = -errno;
 532
 533         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 534
 535         return r;
 536 }
 537
 538 int terminal_vhangup_fd(int fd) {
 539         assert(fd >= 0);
 540
 541         if (ioctl(fd, TIOCVHANGUP) < 0)
 542                 return -errno;
 543
 544         return 0;
 545 }
 546
 547 int terminal_vhangup(const char *name) {
 548         _cleanup_close_ int fd;
 549
 550         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 551         if (fd < 0)
 552                 return fd;
 553
 554         return terminal_vhangup_fd(fd);
 555 }
 556
 557 int vt_disallocate(const char *name) {
 558         _cleanup_close_ int fd = -1;
 559         unsigned u;
 560         int r;
 561
 562         /* Deallocate the VT if possible. If not possible
 563          * (i.e. because it is the active one), at least clear it
 564          * entirely (including the scrollback buffer) */
 565
 566         if (!startswith(name, "/dev/"))
 567                 return -EINVAL;
 568
 569         if (!tty_is_vc(name)) {
 570                 /* So this is not a VT. I guess we cannot deallocate
 571                  * it then. But let's at least clear the screen */
 572
 573                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 574                 if (fd < 0)
 575                         return fd;
 576
 577                 loop_write(fd,
 578                            "\033[r"    /* clear scrolling region */
 579                            "\033[H"    /* move home */
 580                            "\033[2J",  /* clear screen */
 581                            10, false);
 582                 return 0;
 583         }
 584
 585         if (!startswith(name, "/dev/tty"))
 586                 return -EINVAL;
 587
 588         r = safe_atou(name+8, &u);
 589         if (r < 0)
 590                 return r;
 591
 592         if (u <= 0)
 593                 return -EINVAL;
 594
 595         /* Try to deallocate */
 596         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 597         if (fd < 0)
 598                 return fd;
 599
 600         r = ioctl(fd, VT_DISALLOCATE, u);
 601         fd = safe_close(fd);
 602
 603         if (r >= 0)
 604                 return 0;
 605
 606         if (errno != EBUSY)
 607                 return -errno;
 608
 609         /* Couldn't deallocate, so let's clear it fully with
 610          * scrollback */
 611         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 612         if (fd < 0)
 613                 return fd;
 614
 615         loop_write(fd,
 616                    "\033[r"   /* clear scrolling region */
 617                    "\033[H"   /* move home */
 618                    "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
 619                    10, false);
 620         return 0;
 621 }
 622
 623 int make_console_stdio(void) {
 624         int fd, r;
 625
 626         /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
 627
 628         fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
 629         if (fd < 0)
 630                 return log_error_errno(fd, "Failed to acquire terminal: %m");
 631
 632         r = reset_terminal_fd(fd, true);
 633         if (r < 0)
 634                 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
 635
 636         r = make_stdio(fd);
 637         if (r < 0)
 638                 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
 639
 640         return 0;
 641 }
 642
 643 bool tty_is_vc(const char *tty) {
 644         assert(tty);
 645
 646         return vtnr_from_tty(tty) >= 0;
 647 }
 648
 649 bool tty_is_console(const char *tty) {
 650         assert(tty);
 651
 652         return streq(skip_dev_prefix(tty), "console");
 653 }
 654
 655 int vtnr_from_tty(const char *tty) {
 656         int i, r;
 657
 658         assert(tty);
 659
 660         tty = skip_dev_prefix(tty);
 661
 662         if (!startswith(tty, "tty") )
 663                 return -EINVAL;
 664
 665         if (tty[3] < '0' || tty[3] > '9')
 666                 return -EINVAL;
 667
 668         r = safe_atoi(tty+3, &i);
 669         if (r < 0)
 670                 return r;
 671
 672         if (i < 0 || i > 63)
 673                 return -EINVAL;
 674
 675         return i;
 676 }
 677
 678 char *resolve_dev_console(char **active) {
 679         char *tty;
 680
 681         /* Resolve where /dev/console is pointing to, if /sys is actually ours
 682          * (i.e. not read-only-mounted which is a sign for container setups) */
 683
 684         if (path_is_read_only_fs("/sys") > 0)
 685                 return NULL;
 686
 687         if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
 688                 return NULL;
 689
 690         /* If multiple log outputs are configured the last one is what
 691          * /dev/console points to */
 692         tty = strrchr(*active, ' ');
 693         if (tty)
 694                 tty++;
 695         else
 696                 tty = *active;
 697
 698         if (streq(tty, "tty0")) {
 699                 char *tmp;
 700
 701                 /* Get the active VC (e.g. tty1) */
 702                 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
 703                         free(*active);
 704                         tty = *active = tmp;
 705                 }
 706         }
 707
 708         return tty;
 709 }
 710
 711 int get_kernel_consoles(char ***consoles) {
 712         _cleanup_strv_free_ char **con = NULL;
 713         _cleanup_free_ char *line = NULL;
 714         const char *active;
 715         int r;
 716
 717         assert(consoles);
 718
 719         r = read_one_line_file("/sys/class/tty/console/active", &line);
 720         if (r < 0)
 721                 return r;
 722
 723         active = line;
 724         for (;;) {
 725                 _cleanup_free_ char *tty = NULL;
 726                 char *path;
 727
 728                 r = extract_first_word(&active, &tty, NULL, 0);
 729                 if (r < 0)
 730                         return r;
 731                 if (r == 0)
 732                         break;
 733
 734                 if (streq(tty, "tty0")) {
 735                         tty = mfree(tty);
 736                         r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
 737                         if (r < 0)
 738                                 return r;
 739                 }
 740
 741                 path = strappend("/dev/", tty);
 742                 if (!path)
 743                         return -ENOMEM;
 744
 745                 if (access(path, F_OK) < 0) {
 746                         log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
 747                         free(path);
 748                         continue;
 749                 }
 750
 751                 r = strv_consume(&con, path);
 752                 if (r < 0)
 753                         return r;
 754         }
 755
 756         if (strv_isempty(con)) {
 757                 log_debug("No devices found for system console");
 758
 759                 r = strv_extend(&con, "/dev/console");
 760                 if (r < 0)
 761                         return r;
 762         }
 763
 764         *consoles = con;
 765         con = NULL;
 766         return 0;
 767 }
 768
 769 bool tty_is_vc_resolve(const char *tty) {
 770         _cleanup_free_ char *active = NULL;
 771
 772         assert(tty);
 773
 774         tty = skip_dev_prefix(tty);
 775
 776         if (streq(tty, "console")) {
 777                 tty = resolve_dev_console(&active);
 778                 if (!tty)
 779                         return false;
 780         }
 781
 782         return tty_is_vc(tty);
 783 }
 784
 785 const char *default_term_for_tty(const char *tty) {
 786         return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220";
 787 }
 788
 789 int fd_columns(int fd) {
 790         struct winsize ws = {};
 791
 792         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 793                 return -errno;
 794
 795         if (ws.ws_col <= 0)
 796                 return -EIO;
 797
 798         return ws.ws_col;
 799 }
 800
 801 unsigned columns(void) {
 802         const char *e;
 803         int c;
 804
 805         if (_likely_(cached_columns > 0))
 806                 return cached_columns;
 807
 808         c = 0;
 809         e = getenv("COLUMNS");
 810         if (e)
 811                 (void) safe_atoi(e, &c);
 812
 813         if (c <= 0)
 814                 c = fd_columns(STDOUT_FILENO);
 815
 816         if (c <= 0)
 817                 c = 80;
 818
 819         cached_columns = c;
 820         return cached_columns;
 821 }
 822
 823 int fd_lines(int fd) {
 824         struct winsize ws = {};
 825
 826         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 827                 return -errno;
 828
 829         if (ws.ws_row <= 0)
 830                 return -EIO;
 831
 832         return ws.ws_row;
 833 }
 834
 835 unsigned lines(void) {
 836         const char *e;
 837         int l;
 838
 839         if (_likely_(cached_lines > 0))
 840                 return cached_lines;
 841
 842         l = 0;
 843         e = getenv("LINES");
 844         if (e)
 845                 (void) safe_atoi(e, &l);
 846
 847         if (l <= 0)
 848                 l = fd_lines(STDOUT_FILENO);
 849
 850         if (l <= 0)
 851                 l = 24;
 852
 853         cached_lines = l;
 854         return cached_lines;
 855 }
 856
 857 /* intended to be used as a SIGWINCH sighandler */
 858 void columns_lines_cache_reset(int signum) {
 859         cached_columns = 0;
 860         cached_lines = 0;
 861 }
 862
 863 bool on_tty(void) {
 864         static int cached_on_tty = -1;
 865
 866         if (_unlikely_(cached_on_tty < 0))
 867                 cached_on_tty = isatty(STDOUT_FILENO) > 0;
 868
 869         return cached_on_tty;
 870 }
 871
 872 int make_stdio(int fd) {
 873         int r, s, t;
 874
 875         assert(fd >= 0);
 876
 877         r = dup2(fd, STDIN_FILENO);
 878         s = dup2(fd, STDOUT_FILENO);
 879         t = dup2(fd, STDERR_FILENO);
 880
 881         if (fd >= 3)
 882                 safe_close(fd);
 883
 884         if (r < 0 || s < 0 || t < 0)
 885                 return -errno;
 886
 887         /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
 888          * dup2() was a NOP and the bit hence possibly set. */
 889         stdio_unset_cloexec();
 890
 891         return 0;
 892 }
 893
 894 int make_null_stdio(void) {
 895         int null_fd;
 896
 897         null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
 898         if (null_fd < 0)
 899                 return -errno;
 900
 901         return make_stdio(null_fd);
 902 }
 903
 904 int getttyname_malloc(int fd, char **ret) {
 905         size_t l = 100;
 906         int r;
 907
 908         assert(fd >= 0);
 909         assert(ret);
 910
 911         for (;;) {
 912                 char path[l];
 913
 914                 r = ttyname_r(fd, path, sizeof(path));
 915                 if (r == 0) {
 916                         char *c;
 917
 918                         c = strdup(skip_dev_prefix(path));
 919                         if (!c)
 920                                 return -ENOMEM;
 921
 922                         *ret = c;
 923                         return 0;
 924                 }
 925
 926                 if (r != ERANGE)
 927                         return -r;
 928
 929                 l *= 2;
 930         }
 931
 932         return 0;
 933 }
 934
 935 int getttyname_harder(int fd, char **r) {
 936         int k;
 937         char *s = NULL;
 938
 939         k = getttyname_malloc(fd, &s);
 940         if (k < 0)
 941                 return k;
 942
 943         if (streq(s, "tty")) {
 944                 free(s);
 945                 return get_ctty(0, NULL, r);
 946         }
 947
 948         *r = s;
 949         return 0;
 950 }
 951
 952 int get_ctty_devnr(pid_t pid, dev_t *d) {
 953         int r;
 954         _cleanup_free_ char *line = NULL;
 955         const char *p;
 956         unsigned long ttynr;
 957
 958         assert(pid >= 0);
 959
 960         p = procfs_file_alloca(pid, "stat");
 961         r = read_one_line_file(p, &line);
 962         if (r < 0)
 963                 return r;
 964
 965         p = strrchr(line, ')');
 966         if (!p)
 967                 return -EIO;
 968
 969         p++;
 970
 971         if (sscanf(p, " "
 972                    "%*c "  /* state */
 973                    "%*d "  /* ppid */
 974                    "%*d "  /* pgrp */
 975                    "%*d "  /* session */
 976                    "%lu ", /* ttynr */
 977                    &ttynr) != 1)
 978                 return -EIO;
 979
 980         if (major(ttynr) == 0 && minor(ttynr) == 0)
 981                 return -ENXIO;
 982
 983         if (d)
 984                 *d = (dev_t) ttynr;
 985
 986         return 0;
 987 }
 988
 989 int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
 990         char fn[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL;
 991         _cleanup_free_ char *s = NULL;
 992         const char *p;
 993         dev_t devnr;
 994         int k;
 995
 996         assert(r);
 997
 998         k = get_ctty_devnr(pid, &devnr);
 999         if (k < 0)
1000                 return k;
1001
1002         sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr));
1003
1004         k = readlink_malloc(fn, &s);
1005         if (k < 0) {
1006
1007                 if (k != -ENOENT)
1008                         return k;
1009
1010                 /* This is an ugly hack */
1011                 if (major(devnr) == 136) {
1012                         if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
1013                                 return -ENOMEM;
1014                 } else {
1015                         /* Probably something like the ptys which have no
1016                          * symlink in /dev/char. Let's return something
1017                          * vaguely useful. */
1018
1019                         b = strdup(fn + 5);
1020                         if (!b)
1021                                 return -ENOMEM;
1022                 }
1023         } else {
1024                 if (startswith(s, "/dev/"))
1025                         p = s + 5;
1026                 else if (startswith(s, "../"))
1027                         p = s + 3;
1028                 else
1029                         p = s;
1030
1031                 b = strdup(p);
1032                 if (!b)
1033                         return -ENOMEM;
1034         }
1035
1036         *r = b;
1037         if (_devnr)
1038                 *_devnr = devnr;
1039
1040         return 0;
1041 }
1042
1043 int ptsname_malloc(int fd, char **ret) {
1044         size_t l = 100;
1045
1046         assert(fd >= 0);
1047         assert(ret);
1048
1049         for (;;) {
1050                 char *c;
1051
1052                 c = new(char, l);
1053                 if (!c)
1054                         return -ENOMEM;
1055
1056                 if (ptsname_r(fd, c, l) == 0) {
1057                         *ret = c;
1058                         return 0;
1059                 }
1060                 if (errno != ERANGE) {
1061                         free(c);
1062                         return -errno;
1063                 }
1064
1065                 free(c);
1066                 l *= 2;
1067         }
1068 }
1069
1070 int ptsname_namespace(int pty, char **ret) {
1071         int no = -1, r;
1072
1073         /* Like ptsname(), but doesn't assume that the path is
1074          * accessible in the local namespace. */
1075
1076         r = ioctl(pty, TIOCGPTN, &no);
1077         if (r < 0)
1078                 return -errno;
1079
1080         if (no < 0)
1081                 return -EIO;
1082
1083         if (asprintf(ret, "/dev/pts/%i", no) < 0)
1084                 return -ENOMEM;
1085
1086         return 0;
1087 }
1088
1089 int openpt_in_namespace(pid_t pid, int flags) {
1090         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1091         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1092         siginfo_t si;
1093         pid_t child;
1094         int r;
1095
1096         assert(pid > 0);
1097
1098         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1099         if (r < 0)
1100                 return r;
1101
1102         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1103                 return -errno;
1104
1105         child = fork();
1106         if (child < 0)
1107                 return -errno;
1108
1109         if (child == 0) {
1110                 int master;
1111
1112                 pair[0] = safe_close(pair[0]);
1113
1114                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1115                 if (r < 0)
1116                         _exit(EXIT_FAILURE);
1117
1118                 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1119                 if (master < 0)
1120                         _exit(EXIT_FAILURE);
1121
1122                 if (unlockpt(master) < 0)
1123                         _exit(EXIT_FAILURE);
1124
1125                 if (send_one_fd(pair[1], master, 0) < 0)
1126                         _exit(EXIT_FAILURE);
1127
1128                 _exit(EXIT_SUCCESS);
1129         }
1130
1131         pair[1] = safe_close(pair[1]);
1132
1133         r = wait_for_terminate(child, &si);
1134         if (r < 0)
1135                 return r;
1136         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1137                 return -EIO;
1138
1139         return receive_one_fd(pair[0], 0);
1140 }
1141
1142 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1143         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1144         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1145         siginfo_t si;
1146         pid_t child;
1147         int r;
1148
1149         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1150         if (r < 0)
1151                 return r;
1152
1153         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1154                 return -errno;
1155
1156         child = fork();
1157         if (child < 0)
1158                 return -errno;
1159
1160         if (child == 0) {
1161                 int master;
1162
1163                 pair[0] = safe_close(pair[0]);
1164
1165                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1166                 if (r < 0)
1167                         _exit(EXIT_FAILURE);
1168
1169                 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1170                 if (master < 0)
1171                         _exit(EXIT_FAILURE);
1172
1173                 if (send_one_fd(pair[1], master, 0) < 0)
1174                         _exit(EXIT_FAILURE);
1175
1176                 _exit(EXIT_SUCCESS);
1177         }
1178
1179         pair[1] = safe_close(pair[1]);
1180
1181         r = wait_for_terminate(child, &si);
1182         if (r < 0)
1183                 return r;
1184         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1185                 return -EIO;
1186
1187         return receive_one_fd(pair[0], 0);
1188 }
1189
1190 static bool getenv_terminal_is_dumb(void) {
1191         const char *e;
1192
1193         e = getenv("TERM");
1194         if (!e)
1195                 return true;
1196
1197         return streq(e, "dumb");
1198 }
1199
1200 bool terminal_is_dumb(void) {
1201         if (!on_tty())
1202                 return true;
1203
1204         return getenv_terminal_is_dumb();
1205 }
1206
1207 bool colors_enabled(void) {
1208         static int enabled = -1;
1209
1210         if (_unlikely_(enabled < 0)) {
1211                 int val;
1212
1213                 val = getenv_bool("SYSTEMD_COLORS");
1214                 if (val >= 0)
1215                         enabled = val;
1216                 else if (getpid_cached() == 1)
1217                         /* PID1 outputs to the console without holding it open all the time */
1218                         enabled = !getenv_terminal_is_dumb();
1219                 else
1220                         enabled = !terminal_is_dumb();
1221         }
1222
1223         return enabled;
1224 }