src/basic/terminal-util.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <limits.h>
  23 #include <stdarg.h>
  24 #include <stddef.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <sys/inotify.h>
  28 #include <sys/socket.h>
  29 #include <sys/sysmacros.h>
  30 #include <sys/time.h>
  31 #include <linux/kd.h>
  32 #include <linux/tiocl.h>
  33 #include <linux/vt.h>
  34 #include <poll.h>
  35 #include <signal.h>
  36 #include <sys/ioctl.h>
  37 #include <sys/types.h>
  38 #include <termios.h>
  39 #include <unistd.h>
  40
  41 #include "alloc-util.h"
  42 #include "env-util.h"
  43 #include "fd-util.h"
  44 #include "fileio.h"
  45 #include "fs-util.h"
  46 #include "io-util.h"
  47 #include "log.h"
  48 #include "macro.h"
  49 #include "parse-util.h"
  50 #include "process-util.h"
  51 #include "socket-util.h"
  52 #include "stat-util.h"
  53 #include "string-util.h"
  54 #include "strv.h"
  55 #include "terminal-util.h"
  56 #include "time-util.h"
  57 #include "util.h"
  58 #include "path-util.h"
  59
  60 static volatile unsigned cached_columns = 0;
  61 static volatile unsigned cached_lines = 0;
  62
  63 int chvt(int vt) {
  64         _cleanup_close_ int fd;
  65
  66         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
  67         if (fd < 0)
  68                 return -errno;
  69
  70         if (vt <= 0) {
  71                 int tiocl[2] = {
  72                         TIOCL_GETKMSGREDIRECT,
  73                         0
  74                 };
  75
  76                 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
  77                         return -errno;
  78
  79                 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
  80         }
  81
  82         if (ioctl(fd, VT_ACTIVATE, vt) < 0)
  83                 return -errno;
  84
  85         return 0;
  86 }
  87
  88 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
  89         struct termios old_termios, new_termios;
  90         char c, line[LINE_MAX];
  91
  92         assert(f);
  93         assert(ret);
  94
  95         if (tcgetattr(fileno(f), &old_termios) >= 0) {
  96                 new_termios = old_termios;
  97
  98                 new_termios.c_lflag &= ~ICANON;
  99                 new_termios.c_cc[VMIN] = 1;
 100                 new_termios.c_cc[VTIME] = 0;
 101
 102                 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
 103                         size_t k;
 104
 105                         if (t != USEC_INFINITY) {
 106                                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
 107                                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 108                                         return -ETIMEDOUT;
 109                                 }
 110                         }
 111
 112                         k = fread(&c, 1, 1, f);
 113
 114                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 115
 116                         if (k <= 0)
 117                                 return -EIO;
 118
 119                         if (need_nl)
 120                                 *need_nl = c != '\n';
 121
 122                         *ret = c;
 123                         return 0;
 124                 }
 125         }
 126
 127         if (t != USEC_INFINITY) {
 128                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
 129                         return -ETIMEDOUT;
 130         }
 131
 132         errno = 0;
 133         if (!fgets(line, sizeof(line), f))
 134                 return errno > 0 ? -errno : -EIO;
 135
 136         truncate_nl(line);
 137
 138         if (strlen(line) != 1)
 139                 return -EBADMSG;
 140
 141         if (need_nl)
 142                 *need_nl = false;
 143
 144         *ret = line[0];
 145         return 0;
 146 }
 147
 148 #define DEFAULT_ASK_REFRESH_USEC (2*USEC_PER_SEC)
 149
 150 int ask_char(char *ret, const char *replies, const char *fmt, ...) {
 151         int r;
 152
 153         assert(ret);
 154         assert(replies);
 155         assert(fmt);
 156
 157         for (;;) {
 158                 va_list ap;
 159                 char c;
 160                 bool need_nl = true;
 161
 162                 if (colors_enabled())
 163                         fputs(ANSI_HIGHLIGHT, stdout);
 164
 165                 putchar('\r');
 166
 167                 va_start(ap, fmt);
 168                 vprintf(fmt, ap);
 169                 va_end(ap);
 170
 171                 if (colors_enabled())
 172                         fputs(ANSI_NORMAL, stdout);
 173
 174                 fflush(stdout);
 175
 176                 r = read_one_char(stdin, &c, DEFAULT_ASK_REFRESH_USEC, &need_nl);
 177                 if (r < 0) {
 178
 179                         if (r == -ETIMEDOUT)
 180                                 continue;
 181
 182                         if (r == -EBADMSG) {
 183                                 puts("Bad input, please try again.");
 184                                 continue;
 185                         }
 186
 187                         putchar('\n');
 188                         return r;
 189                 }
 190
 191                 if (need_nl)
 192                         putchar('\n');
 193
 194                 if (strchr(replies, c)) {
 195                         *ret = c;
 196                         return 0;
 197                 }
 198
 199                 puts("Read unexpected character, please try again.");
 200         }
 201 }
 202
 203 int ask_string(char **ret, const char *text, ...) {
 204         assert(ret);
 205         assert(text);
 206
 207         for (;;) {
 208                 char line[LINE_MAX];
 209                 va_list ap;
 210
 211                 if (colors_enabled())
 212                         fputs(ANSI_HIGHLIGHT, stdout);
 213
 214                 va_start(ap, text);
 215                 vprintf(text, ap);
 216                 va_end(ap);
 217
 218                 if (colors_enabled())
 219                         fputs(ANSI_NORMAL, stdout);
 220
 221                 fflush(stdout);
 222
 223                 errno = 0;
 224                 if (!fgets(line, sizeof(line), stdin))
 225                         return errno > 0 ? -errno : -EIO;
 226
 227                 if (!endswith(line, "\n"))
 228                         putchar('\n');
 229                 else {
 230                         char *s;
 231
 232                         if (isempty(line))
 233                                 continue;
 234
 235                         truncate_nl(line);
 236                         s = strdup(line);
 237                         if (!s)
 238                                 return -ENOMEM;
 239
 240                         *ret = s;
 241                         return 0;
 242                 }
 243         }
 244 }
 245
 246 int reset_terminal_fd(int fd, bool switch_to_text) {
 247         struct termios termios;
 248         _cleanup_free_ char *utf8 = NULL;
 249         int kb;
 250         int r = 0;
 251
 252         /* Set terminal to some sane defaults */
 253
 254         assert(fd >= 0);
 255
 256         /* We leave locked terminal attributes untouched, so that
 257          * Plymouth may set whatever it wants to set, and we don't
 258          * interfere with that. */
 259
 260         /* Disable exclusive mode, just in case */
 261         (void) ioctl(fd, TIOCNXCL);
 262
 263         /* Switch to text mode */
 264         if (switch_to_text)
 265                 (void) ioctl(fd, KDSETMODE, KD_TEXT);
 266
 267         /* Set default keyboard mode */
 268         if (read_one_line_file("/sys/module/vt/parameters/default_utf8", &utf8) >= 0 && parse_boolean(utf8) == 0)
 269                 kb = K_XLATE;
 270         else
 271                 kb = K_UNICODE;
 272         (void) ioctl(fd, KDSKBMODE, kb);
 273
 274         if (tcgetattr(fd, &termios) < 0) {
 275                 r = -errno;
 276                 goto finish;
 277         }
 278
 279         /* We only reset the stuff that matters to the software. How
 280          * hardware is set up we don't touch assuming that somebody
 281          * else will do that for us */
 282
 283         termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
 284         termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
 285         termios.c_oflag |= ONLCR;
 286         termios.c_cflag |= CREAD;
 287         termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
 288
 289         termios.c_cc[VINTR]    =   03;  /* ^C */
 290         termios.c_cc[VQUIT]    =  034;  /* ^\ */
 291         termios.c_cc[VERASE]   = 0177;
 292         termios.c_cc[VKILL]    =  025;  /* ^X */
 293         termios.c_cc[VEOF]     =   04;  /* ^D */
 294         termios.c_cc[VSTART]   =  021;  /* ^Q */
 295         termios.c_cc[VSTOP]    =  023;  /* ^S */
 296         termios.c_cc[VSUSP]    =  032;  /* ^Z */
 297         termios.c_cc[VLNEXT]   =  026;  /* ^V */
 298         termios.c_cc[VWERASE]  =  027;  /* ^W */
 299         termios.c_cc[VREPRINT] =  022;  /* ^R */
 300         termios.c_cc[VEOL]     =    0;
 301         termios.c_cc[VEOL2]    =    0;
 302
 303         termios.c_cc[VTIME]  = 0;
 304         termios.c_cc[VMIN]   = 1;
 305
 306         if (tcsetattr(fd, TCSANOW, &termios) < 0)
 307                 r = -errno;
 308
 309 finish:
 310         /* Just in case, flush all crap out */
 311         (void) tcflush(fd, TCIOFLUSH);
 312
 313         return r;
 314 }
 315
 316 int reset_terminal(const char *name) {
 317         _cleanup_close_ int fd = -1;
 318
 319         /* We open the terminal with O_NONBLOCK here, to ensure we
 320          * don't block on carrier if this is a terminal with carrier
 321          * configured. */
 322
 323         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 324         if (fd < 0)
 325                 return fd;
 326
 327         return reset_terminal_fd(fd, true);
 328 }
 329
 330 int open_terminal(const char *name, int mode) {
 331         int fd, r;
 332         unsigned c = 0;
 333
 334         /*
 335          * If a TTY is in the process of being closed opening it might
 336          * cause EIO. This is horribly awful, but unlikely to be
 337          * changed in the kernel. Hence we work around this problem by
 338          * retrying a couple of times.
 339          *
 340          * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
 341          */
 342
 343         if (mode & O_CREAT)
 344                 return -EINVAL;
 345
 346         for (;;) {
 347                 fd = open(name, mode, 0);
 348                 if (fd >= 0)
 349                         break;
 350
 351                 if (errno != EIO)
 352                         return -errno;
 353
 354                 /* Max 1s in total */
 355                 if (c >= 20)
 356                         return -errno;
 357
 358                 usleep(50 * USEC_PER_MSEC);
 359                 c++;
 360         }
 361
 362         r = isatty(fd);
 363         if (r == 0) {
 364                 safe_close(fd);
 365                 return -ENOTTY;
 366         }
 367
 368         return fd;
 369 }
 370
 371 int acquire_terminal(
 372                 const char *name,
 373                 bool fail,
 374                 bool force,
 375                 bool ignore_tiocstty_eperm,
 376                 usec_t timeout) {
 377
 378         int fd = -1, notify = -1, r = 0, wd = -1;
 379         usec_t ts = 0;
 380
 381         assert(name);
 382
 383         /* We use inotify to be notified when the tty is closed. We
 384          * create the watch before checking if we can actually acquire
 385          * it, so that we don't lose any event.
 386          *
 387          * Note: strictly speaking this actually watches for the
 388          * device being closed, it does *not* really watch whether a
 389          * tty loses its controlling process. However, unless some
 390          * rogue process uses TIOCNOTTY on /dev/tty *after* closing
 391          * its tty otherwise this will not become a problem. As long
 392          * as the administrator makes sure not configure any service
 393          * on the same tty as an untrusted user this should not be a
 394          * problem. (Which he probably should not do anyway.) */
 395
 396         if (timeout != USEC_INFINITY)
 397                 ts = now(CLOCK_MONOTONIC);
 398
 399         if (!fail && !force) {
 400                 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
 401                 if (notify < 0) {
 402                         r = -errno;
 403                         goto fail;
 404                 }
 405
 406                 wd = inotify_add_watch(notify, name, IN_CLOSE);
 407                 if (wd < 0) {
 408                         r = -errno;
 409                         goto fail;
 410                 }
 411         }
 412
 413         for (;;) {
 414                 struct sigaction sa_old, sa_new = {
 415                         .sa_handler = SIG_IGN,
 416                         .sa_flags = SA_RESTART,
 417                 };
 418
 419                 if (notify >= 0) {
 420                         r = flush_fd(notify);
 421                         if (r < 0)
 422                                 goto fail;
 423                 }
 424
 425                 /* We pass here O_NOCTTY only so that we can check the return
 426                  * value TIOCSCTTY and have a reliable way to figure out if we
 427                  * successfully became the controlling process of the tty */
 428                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 429                 if (fd < 0)
 430                         return fd;
 431
 432                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 433                  * if we already own the tty. */
 434                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 435
 436                 /* First, try to get the tty */
 437                 if (ioctl(fd, TIOCSCTTY, force) < 0)
 438                         r = -errno;
 439
 440                 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 441
 442                 /* Sometimes, it makes sense to ignore TIOCSCTTY
 443                  * returning EPERM, i.e. when very likely we already
 444                  * are have this controlling terminal. */
 445                 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
 446                         r = 0;
 447
 448                 if (r < 0 && (force || fail || r != -EPERM))
 449                         goto fail;
 450
 451                 if (r >= 0)
 452                         break;
 453
 454                 assert(!fail);
 455                 assert(!force);
 456                 assert(notify >= 0);
 457
 458                 for (;;) {
 459                         union inotify_event_buffer buffer;
 460                         struct inotify_event *e;
 461                         ssize_t l;
 462
 463                         if (timeout != USEC_INFINITY) {
 464                                 usec_t n;
 465
 466                                 n = now(CLOCK_MONOTONIC);
 467                                 if (ts + timeout < n) {
 468                                         r = -ETIMEDOUT;
 469                                         goto fail;
 470                                 }
 471
 472                                 r = fd_wait_for_event(notify, POLLIN, ts + timeout - n);
 473                                 if (r < 0)
 474                                         goto fail;
 475
 476                                 if (r == 0) {
 477                                         r = -ETIMEDOUT;
 478                                         goto fail;
 479                                 }
 480                         }
 481
 482                         l = read(notify, &buffer, sizeof(buffer));
 483                         if (l < 0) {
 484                                 if (errno == EINTR || errno == EAGAIN)
 485                                         continue;
 486
 487                                 r = -errno;
 488                                 goto fail;
 489                         }
 490
 491                         FOREACH_INOTIFY_EVENT(e, buffer, l) {
 492                                 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
 493                                         r = -EIO;
 494                                         goto fail;
 495                                 }
 496                         }
 497
 498                         break;
 499                 }
 500
 501                 /* We close the tty fd here since if the old session
 502                  * ended our handle will be dead. It's important that
 503                  * we do this after sleeping, so that we don't enter
 504                  * an endless loop. */
 505                 fd = safe_close(fd);
 506         }
 507
 508         safe_close(notify);
 509
 510         return fd;
 511
 512 fail:
 513         safe_close(fd);
 514         safe_close(notify);
 515
 516         return r;
 517 }
 518
 519 int release_terminal(void) {
 520         static const struct sigaction sa_new = {
 521                 .sa_handler = SIG_IGN,
 522                 .sa_flags = SA_RESTART,
 523         };
 524
 525         _cleanup_close_ int fd = -1;
 526         struct sigaction sa_old;
 527         int r = 0;
 528
 529         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 530         if (fd < 0)
 531                 return -errno;
 532
 533         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 534          * by our own TIOCNOTTY */
 535         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 536
 537         if (ioctl(fd, TIOCNOTTY) < 0)
 538                 r = -errno;
 539
 540         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 541
 542         return r;
 543 }
 544
 545 int terminal_vhangup_fd(int fd) {
 546         assert(fd >= 0);
 547
 548         if (ioctl(fd, TIOCVHANGUP) < 0)
 549                 return -errno;
 550
 551         return 0;
 552 }
 553
 554 int terminal_vhangup(const char *name) {
 555         _cleanup_close_ int fd;
 556
 557         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 558         if (fd < 0)
 559                 return fd;
 560
 561         return terminal_vhangup_fd(fd);
 562 }
 563
 564 int vt_disallocate(const char *name) {
 565         _cleanup_close_ int fd = -1;
 566         const char *e, *n;
 567         unsigned u;
 568         int r;
 569
 570         /* Deallocate the VT if possible. If not possible
 571          * (i.e. because it is the active one), at least clear it
 572          * entirely (including the scrollback buffer) */
 573
 574         e = path_startswith(name, "/dev/");
 575         if (!e)
 576                 return -EINVAL;
 577
 578         if (!tty_is_vc(name)) {
 579                 /* So this is not a VT. I guess we cannot deallocate
 580                  * it then. But let's at least clear the screen */
 581
 582                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 583                 if (fd < 0)
 584                         return fd;
 585
 586                 loop_write(fd,
 587                            "\033[r"    /* clear scrolling region */
 588                            "\033[H"    /* move home */
 589                            "\033[2J",  /* clear screen */
 590                            10, false);
 591                 return 0;
 592         }
 593
 594         n = startswith(e, "tty");
 595         if (!n)
 596                 return -EINVAL;
 597
 598         r = safe_atou(n, &u);
 599         if (r < 0)
 600                 return r;
 601
 602         if (u <= 0)
 603                 return -EINVAL;
 604
 605         /* Try to deallocate */
 606         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 607         if (fd < 0)
 608                 return fd;
 609
 610         r = ioctl(fd, VT_DISALLOCATE, u);
 611         fd = safe_close(fd);
 612
 613         if (r >= 0)
 614                 return 0;
 615
 616         if (errno != EBUSY)
 617                 return -errno;
 618
 619         /* Couldn't deallocate, so let's clear it fully with
 620          * scrollback */
 621         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 622         if (fd < 0)
 623                 return fd;
 624
 625         loop_write(fd,
 626                    "\033[r"   /* clear scrolling region */
 627                    "\033[H"   /* move home */
 628                    "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
 629                    10, false);
 630         return 0;
 631 }
 632
 633 int make_console_stdio(void) {
 634         int fd, r;
 635
 636         /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
 637
 638         fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
 639         if (fd < 0)
 640                 return log_error_errno(fd, "Failed to acquire terminal: %m");
 641
 642         r = reset_terminal_fd(fd, true);
 643         if (r < 0)
 644                 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
 645
 646         r = make_stdio(fd);
 647         if (r < 0)
 648                 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
 649
 650         return 0;
 651 }
 652
 653 bool tty_is_vc(const char *tty) {
 654         assert(tty);
 655
 656         return vtnr_from_tty(tty) >= 0;
 657 }
 658
 659 bool tty_is_console(const char *tty) {
 660         assert(tty);
 661
 662         return streq(skip_dev_prefix(tty), "console");
 663 }
 664
 665 int vtnr_from_tty(const char *tty) {
 666         int i, r;
 667
 668         assert(tty);
 669
 670         tty = skip_dev_prefix(tty);
 671
 672         if (!startswith(tty, "tty") )
 673                 return -EINVAL;
 674
 675         if (tty[3] < '0' || tty[3] > '9')
 676                 return -EINVAL;
 677
 678         r = safe_atoi(tty+3, &i);
 679         if (r < 0)
 680                 return r;
 681
 682         if (i < 0 || i > 63)
 683                 return -EINVAL;
 684
 685         return i;
 686 }
 687
 688 char *resolve_dev_console(char **active) {
 689         char *tty;
 690
 691         /* Resolve where /dev/console is pointing to, if /sys is actually ours
 692          * (i.e. not read-only-mounted which is a sign for container setups) */
 693
 694         if (path_is_read_only_fs("/sys") > 0)
 695                 return NULL;
 696
 697         if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
 698                 return NULL;
 699
 700         /* If multiple log outputs are configured the last one is what
 701          * /dev/console points to */
 702         tty = strrchr(*active, ' ');
 703         if (tty)
 704                 tty++;
 705         else
 706                 tty = *active;
 707
 708         if (streq(tty, "tty0")) {
 709                 char *tmp;
 710
 711                 /* Get the active VC (e.g. tty1) */
 712                 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
 713                         free(*active);
 714                         tty = *active = tmp;
 715                 }
 716         }
 717
 718         return tty;
 719 }
 720
 721 int get_kernel_consoles(char ***consoles) {
 722         _cleanup_strv_free_ char **con = NULL;
 723         _cleanup_free_ char *line = NULL;
 724         const char *active;
 725         int r;
 726
 727         assert(consoles);
 728
 729         r = read_one_line_file("/sys/class/tty/console/active", &line);
 730         if (r < 0)
 731                 return r;
 732
 733         active = line;
 734         for (;;) {
 735                 _cleanup_free_ char *tty = NULL;
 736                 char *path;
 737
 738                 r = extract_first_word(&active, &tty, NULL, 0);
 739                 if (r < 0)
 740                         return r;
 741                 if (r == 0)
 742                         break;
 743
 744                 if (streq(tty, "tty0")) {
 745                         tty = mfree(tty);
 746                         r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
 747                         if (r < 0)
 748                                 return r;
 749                 }
 750
 751                 path = strappend("/dev/", tty);
 752                 if (!path)
 753                         return -ENOMEM;
 754
 755                 if (access(path, F_OK) < 0) {
 756                         log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
 757                         free(path);
 758                         continue;
 759                 }
 760
 761                 r = strv_consume(&con, path);
 762                 if (r < 0)
 763                         return r;
 764         }
 765
 766         if (strv_isempty(con)) {
 767                 log_debug("No devices found for system console");
 768
 769                 r = strv_extend(&con, "/dev/console");
 770                 if (r < 0)
 771                         return r;
 772         }
 773
 774         *consoles = con;
 775         con = NULL;
 776         return 0;
 777 }
 778
 779 bool tty_is_vc_resolve(const char *tty) {
 780         _cleanup_free_ char *active = NULL;
 781
 782         assert(tty);
 783
 784         tty = skip_dev_prefix(tty);
 785
 786         if (streq(tty, "console")) {
 787                 tty = resolve_dev_console(&active);
 788                 if (!tty)
 789                         return false;
 790         }
 791
 792         return tty_is_vc(tty);
 793 }
 794
 795 const char *default_term_for_tty(const char *tty) {
 796         return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220";
 797 }
 798
 799 int fd_columns(int fd) {
 800         struct winsize ws = {};
 801
 802         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 803                 return -errno;
 804
 805         if (ws.ws_col <= 0)
 806                 return -EIO;
 807
 808         return ws.ws_col;
 809 }
 810
 811 unsigned columns(void) {
 812         const char *e;
 813         int c;
 814
 815         if (_likely_(cached_columns > 0))
 816                 return cached_columns;
 817
 818         c = 0;
 819         e = getenv("COLUMNS");
 820         if (e)
 821                 (void) safe_atoi(e, &c);
 822
 823         if (c <= 0)
 824                 c = fd_columns(STDOUT_FILENO);
 825
 826         if (c <= 0)
 827                 c = 80;
 828
 829         cached_columns = c;
 830         return cached_columns;
 831 }
 832
 833 int fd_lines(int fd) {
 834         struct winsize ws = {};
 835
 836         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 837                 return -errno;
 838
 839         if (ws.ws_row <= 0)
 840                 return -EIO;
 841
 842         return ws.ws_row;
 843 }
 844
 845 unsigned lines(void) {
 846         const char *e;
 847         int l;
 848
 849         if (_likely_(cached_lines > 0))
 850                 return cached_lines;
 851
 852         l = 0;
 853         e = getenv("LINES");
 854         if (e)
 855                 (void) safe_atoi(e, &l);
 856
 857         if (l <= 0)
 858                 l = fd_lines(STDOUT_FILENO);
 859
 860         if (l <= 0)
 861                 l = 24;
 862
 863         cached_lines = l;
 864         return cached_lines;
 865 }
 866
 867 /* intended to be used as a SIGWINCH sighandler */
 868 void columns_lines_cache_reset(int signum) {
 869         cached_columns = 0;
 870         cached_lines = 0;
 871 }
 872
 873 bool on_tty(void) {
 874         static int cached_on_tty = -1;
 875
 876         if (_unlikely_(cached_on_tty < 0))
 877                 cached_on_tty = isatty(STDOUT_FILENO) > 0;
 878
 879         return cached_on_tty;
 880 }
 881
 882 int make_stdio(int fd) {
 883         int r, s, t;
 884
 885         assert(fd >= 0);
 886
 887         r = dup2(fd, STDIN_FILENO);
 888         s = dup2(fd, STDOUT_FILENO);
 889         t = dup2(fd, STDERR_FILENO);
 890
 891         if (fd >= 3)
 892                 safe_close(fd);
 893
 894         if (r < 0 || s < 0 || t < 0)
 895                 return -errno;
 896
 897         /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
 898          * dup2() was a NOP and the bit hence possibly set. */
 899         stdio_unset_cloexec();
 900
 901         return 0;
 902 }
 903
 904 int make_null_stdio(void) {
 905         int null_fd;
 906
 907         null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
 908         if (null_fd < 0)
 909                 return -errno;
 910
 911         return make_stdio(null_fd);
 912 }
 913
 914 int getttyname_malloc(int fd, char **ret) {
 915         size_t l = 100;
 916         int r;
 917
 918         assert(fd >= 0);
 919         assert(ret);
 920
 921         for (;;) {
 922                 char path[l];
 923
 924                 r = ttyname_r(fd, path, sizeof(path));
 925                 if (r == 0) {
 926                         char *c;
 927
 928                         c = strdup(skip_dev_prefix(path));
 929                         if (!c)
 930                                 return -ENOMEM;
 931
 932                         *ret = c;
 933                         return 0;
 934                 }
 935
 936                 if (r != ERANGE)
 937                         return -r;
 938
 939                 l *= 2;
 940         }
 941
 942         return 0;
 943 }
 944
 945 int getttyname_harder(int fd, char **r) {
 946         int k;
 947         char *s = NULL;
 948
 949         k = getttyname_malloc(fd, &s);
 950         if (k < 0)
 951                 return k;
 952
 953         if (streq(s, "tty")) {
 954                 free(s);
 955                 return get_ctty(0, NULL, r);
 956         }
 957
 958         *r = s;
 959         return 0;
 960 }
 961
 962 int get_ctty_devnr(pid_t pid, dev_t *d) {
 963         int r;
 964         _cleanup_free_ char *line = NULL;
 965         const char *p;
 966         unsigned long ttynr;
 967
 968         assert(pid >= 0);
 969
 970         p = procfs_file_alloca(pid, "stat");
 971         r = read_one_line_file(p, &line);
 972         if (r < 0)
 973                 return r;
 974
 975         p = strrchr(line, ')');
 976         if (!p)
 977                 return -EIO;
 978
 979         p++;
 980
 981         if (sscanf(p, " "
 982                    "%*c "  /* state */
 983                    "%*d "  /* ppid */
 984                    "%*d "  /* pgrp */
 985                    "%*d "  /* session */
 986                    "%lu ", /* ttynr */
 987                    &ttynr) != 1)
 988                 return -EIO;
 989
 990         if (major(ttynr) == 0 && minor(ttynr) == 0)
 991                 return -ENXIO;
 992
 993         if (d)
 994                 *d = (dev_t) ttynr;
 995
 996         return 0;
 997 }
 998
 999 int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
1000         char fn[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL;
1001         _cleanup_free_ char *s = NULL;
1002         const char *p;
1003         dev_t devnr;
1004         int k;
1005
1006         assert(r);
1007
1008         k = get_ctty_devnr(pid, &devnr);
1009         if (k < 0)
1010                 return k;
1011
1012         sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr));
1013
1014         k = readlink_malloc(fn, &s);
1015         if (k < 0) {
1016
1017                 if (k != -ENOENT)
1018                         return k;
1019
1020                 /* This is an ugly hack */
1021                 if (major(devnr) == 136) {
1022                         if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
1023                                 return -ENOMEM;
1024                 } else {
1025                         /* Probably something like the ptys which have no
1026                          * symlink in /dev/char. Let's return something
1027                          * vaguely useful. */
1028
1029                         b = strdup(fn + 5);
1030                         if (!b)
1031                                 return -ENOMEM;
1032                 }
1033         } else {
1034                 if (startswith(s, "/dev/"))
1035                         p = s + 5;
1036                 else if (startswith(s, "../"))
1037                         p = s + 3;
1038                 else
1039                         p = s;
1040
1041                 b = strdup(p);
1042                 if (!b)
1043                         return -ENOMEM;
1044         }
1045
1046         *r = b;
1047         if (_devnr)
1048                 *_devnr = devnr;
1049
1050         return 0;
1051 }
1052
1053 int ptsname_malloc(int fd, char **ret) {
1054         size_t l = 100;
1055
1056         assert(fd >= 0);
1057         assert(ret);
1058
1059         for (;;) {
1060                 char *c;
1061
1062                 c = new(char, l);
1063                 if (!c)
1064                         return -ENOMEM;
1065
1066                 if (ptsname_r(fd, c, l) == 0) {
1067                         *ret = c;
1068                         return 0;
1069                 }
1070                 if (errno != ERANGE) {
1071                         free(c);
1072                         return -errno;
1073                 }
1074
1075                 free(c);
1076                 l *= 2;
1077         }
1078 }
1079
1080 int ptsname_namespace(int pty, char **ret) {
1081         int no = -1, r;
1082
1083         /* Like ptsname(), but doesn't assume that the path is
1084          * accessible in the local namespace. */
1085
1086         r = ioctl(pty, TIOCGPTN, &no);
1087         if (r < 0)
1088                 return -errno;
1089
1090         if (no < 0)
1091                 return -EIO;
1092
1093         if (asprintf(ret, "/dev/pts/%i", no) < 0)
1094                 return -ENOMEM;
1095
1096         return 0;
1097 }
1098
1099 int openpt_in_namespace(pid_t pid, int flags) {
1100         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1101         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1102         siginfo_t si;
1103         pid_t child;
1104         int r;
1105
1106         assert(pid > 0);
1107
1108         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1109         if (r < 0)
1110                 return r;
1111
1112         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1113                 return -errno;
1114
1115         child = fork();
1116         if (child < 0)
1117                 return -errno;
1118
1119         if (child == 0) {
1120                 int master;
1121
1122                 pair[0] = safe_close(pair[0]);
1123
1124                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1125                 if (r < 0)
1126                         _exit(EXIT_FAILURE);
1127
1128                 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1129                 if (master < 0)
1130                         _exit(EXIT_FAILURE);
1131
1132                 if (unlockpt(master) < 0)
1133                         _exit(EXIT_FAILURE);
1134
1135                 if (send_one_fd(pair[1], master, 0) < 0)
1136                         _exit(EXIT_FAILURE);
1137
1138                 _exit(EXIT_SUCCESS);
1139         }
1140
1141         pair[1] = safe_close(pair[1]);
1142
1143         r = wait_for_terminate(child, &si);
1144         if (r < 0)
1145                 return r;
1146         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1147                 return -EIO;
1148
1149         return receive_one_fd(pair[0], 0);
1150 }
1151
1152 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1153         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1154         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1155         siginfo_t si;
1156         pid_t child;
1157         int r;
1158
1159         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1160         if (r < 0)
1161                 return r;
1162
1163         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1164                 return -errno;
1165
1166         child = fork();
1167         if (child < 0)
1168                 return -errno;
1169
1170         if (child == 0) {
1171                 int master;
1172
1173                 pair[0] = safe_close(pair[0]);
1174
1175                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1176                 if (r < 0)
1177                         _exit(EXIT_FAILURE);
1178
1179                 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1180                 if (master < 0)
1181                         _exit(EXIT_FAILURE);
1182
1183                 if (send_one_fd(pair[1], master, 0) < 0)
1184                         _exit(EXIT_FAILURE);
1185
1186                 _exit(EXIT_SUCCESS);
1187         }
1188
1189         pair[1] = safe_close(pair[1]);
1190
1191         r = wait_for_terminate(child, &si);
1192         if (r < 0)
1193                 return r;
1194         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1195                 return -EIO;
1196
1197         return receive_one_fd(pair[0], 0);
1198 }
1199
1200 static bool getenv_terminal_is_dumb(void) {
1201         const char *e;
1202
1203         e = getenv("TERM");
1204         if (!e)
1205                 return true;
1206
1207         return streq(e, "dumb");
1208 }
1209
1210 bool terminal_is_dumb(void) {
1211         if (!on_tty())
1212                 return true;
1213
1214         return getenv_terminal_is_dumb();
1215 }
1216
1217 bool colors_enabled(void) {
1218         static int enabled = -1;
1219
1220         if (_unlikely_(enabled < 0)) {
1221                 int val;
1222
1223                 val = getenv_bool("SYSTEMD_COLORS");
1224                 if (val >= 0)
1225                         enabled = val;
1226                 else if (getpid_cached() == 1)
1227                         /* PID1 outputs to the console without holding it open all the time */
1228                         enabled = !getenv_terminal_is_dumb();
1229                 else
1230                         enabled = !terminal_is_dumb();
1231         }
1232
1233         return enabled;
1234 }