src/basic/terminal-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <limits.h>
   6 #include <linux/kd.h>
   7 #include <linux/tiocl.h>
   8 #include <linux/vt.h>
   9 #include <poll.h>
  10 #include <signal.h>
  11 #include <stdarg.h>
  12 #include <stddef.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <sys/inotify.h>
  16 #include <sys/ioctl.h>
  17 #include <sys/socket.h>
  18 #include <sys/sysmacros.h>
  19 #include <sys/time.h>
  20 #include <sys/types.h>
  21 #include <sys/utsname.h>
  22 #include <termios.h>
  23 #include <unistd.h>
  24
  25 #include "alloc-util.h"
  26 #include "copy.h"
  27 #include "def.h"
  28 #include "env-util.h"
  29 #include "fd-util.h"
  30 #include "fileio.h"
  31 #include "fs-util.h"
  32 #include "io-util.h"
  33 #include "log.h"
  34 #include "macro.h"
  35 #include "parse-util.h"
  36 #include "path-util.h"
  37 #include "proc-cmdline.h"
  38 #include "process-util.h"
  39 #include "socket-util.h"
  40 #include "stat-util.h"
  41 #include "string-util.h"
  42 #include "strv.h"
  43 #include "terminal-util.h"
  44 #include "time-util.h"
  45 #include "util.h"
  46
  47 static volatile unsigned cached_columns = 0;
  48 static volatile unsigned cached_lines = 0;
  49
  50 static volatile int cached_on_tty = -1;
  51 static volatile int cached_colors_enabled = -1;
  52 static volatile int cached_underline_enabled = -1;
  53
  54 int chvt(int vt) {
  55         _cleanup_close_ int fd;
  56
  57         /* Switch to the specified vt number. If the VT is specified <= 0 switch to the VT the kernel log messages go,
  58          * if that's configured. */
  59
  60         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
  61         if (fd < 0)
  62                 return -errno;
  63
  64         if (vt <= 0) {
  65                 int tiocl[2] = {
  66                         TIOCL_GETKMSGREDIRECT,
  67                         0
  68                 };
  69
  70                 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
  71                         return -errno;
  72
  73                 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
  74         }
  75
  76         if (ioctl(fd, VT_ACTIVATE, vt) < 0)
  77                 return -errno;
  78
  79         return 0;
  80 }
  81
  82 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
  83         _cleanup_free_ char *line = NULL;
  84         struct termios old_termios;
  85         int r;
  86
  87         assert(f);
  88         assert(ret);
  89
  90         /* If this is a terminal, then switch canonical mode off, so that we can read a single character */
  91         if (tcgetattr(fileno(f), &old_termios) >= 0) {
  92                 struct termios new_termios = old_termios;
  93
  94                 new_termios.c_lflag &= ~ICANON;
  95                 new_termios.c_cc[VMIN] = 1;
  96                 new_termios.c_cc[VTIME] = 0;
  97
  98                 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
  99                         char c;
 100
 101                         if (t != USEC_INFINITY) {
 102                                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
 103                                         (void) tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 104                                         return -ETIMEDOUT;
 105                                 }
 106                         }
 107
 108                         r = safe_fgetc(f, &c);
 109                         (void) tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 110                         if (r < 0)
 111                                 return r;
 112                         if (r == 0)
 113                                 return -EIO;
 114
 115                         if (need_nl)
 116                                 *need_nl = c != '\n';
 117
 118                         *ret = c;
 119                         return 0;
 120                 }
 121         }
 122
 123         if (t != USEC_INFINITY) {
 124                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
 125                         return -ETIMEDOUT;
 126         }
 127
 128         /* If this is not a terminal, then read a full line instead */
 129
 130         r = read_line(f, 16, &line); /* longer than necessary, to eat up UTF-8 chars/vt100 key sequences */
 131         if (r < 0)
 132                 return r;
 133         if (r == 0)
 134                 return -EIO;
 135
 136         if (strlen(line) != 1)
 137                 return -EBADMSG;
 138
 139         if (need_nl)
 140                 *need_nl = false;
 141
 142         *ret = line[0];
 143         return 0;
 144 }
 145
 146 #define DEFAULT_ASK_REFRESH_USEC (2*USEC_PER_SEC)
 147
 148 int ask_char(char *ret, const char *replies, const char *fmt, ...) {
 149         int r;
 150
 151         assert(ret);
 152         assert(replies);
 153         assert(fmt);
 154
 155         for (;;) {
 156                 va_list ap;
 157                 char c;
 158                 bool need_nl = true;
 159
 160                 if (colors_enabled())
 161                         fputs(ANSI_HIGHLIGHT, stdout);
 162
 163                 putchar('\r');
 164
 165                 va_start(ap, fmt);
 166                 vprintf(fmt, ap);
 167                 va_end(ap);
 168
 169                 if (colors_enabled())
 170                         fputs(ANSI_NORMAL, stdout);
 171
 172                 fflush(stdout);
 173
 174                 r = read_one_char(stdin, &c, DEFAULT_ASK_REFRESH_USEC, &need_nl);
 175                 if (r < 0) {
 176
 177                         if (r == -ETIMEDOUT)
 178                                 continue;
 179
 180                         if (r == -EBADMSG) {
 181                                 puts("Bad input, please try again.");
 182                                 continue;
 183                         }
 184
 185                         putchar('\n');
 186                         return r;
 187                 }
 188
 189                 if (need_nl)
 190                         putchar('\n');
 191
 192                 if (strchr(replies, c)) {
 193                         *ret = c;
 194                         return 0;
 195                 }
 196
 197                 puts("Read unexpected character, please try again.");
 198         }
 199 }
 200
 201 int ask_string(char **ret, const char *text, ...) {
 202         int r;
 203
 204         assert(ret);
 205         assert(text);
 206
 207         for (;;) {
 208                 _cleanup_free_ char *line = NULL;
 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                 r = read_line(stdin, LONG_LINE_MAX, &line);
 224                 if (r < 0)
 225                         return r;
 226                 if (r == 0)
 227                         return -EIO;
 228
 229                 if (!isempty(line)) {
 230                         *ret = TAKE_PTR(line);
 231                         return 0;
 232                 }
 233         }
 234 }
 235
 236 int reset_terminal_fd(int fd, bool switch_to_text) {
 237         struct termios termios;
 238         int r = 0;
 239
 240         /* Set terminal to some sane defaults */
 241
 242         assert(fd >= 0);
 243
 244         /* We leave locked terminal attributes untouched, so that
 245          * Plymouth may set whatever it wants to set, and we don't
 246          * interfere with that. */
 247
 248         /* Disable exclusive mode, just in case */
 249         (void) ioctl(fd, TIOCNXCL);
 250
 251         /* Switch to text mode */
 252         if (switch_to_text)
 253                 (void) ioctl(fd, KDSETMODE, KD_TEXT);
 254
 255         /* Set default keyboard mode */
 256         (void) vt_reset_keyboard(fd);
 257
 258         if (tcgetattr(fd, &termios) < 0) {
 259                 r = -errno;
 260                 goto finish;
 261         }
 262
 263         /* We only reset the stuff that matters to the software. How
 264          * hardware is set up we don't touch assuming that somebody
 265          * else will do that for us */
 266
 267         termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
 268         termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
 269         termios.c_oflag |= ONLCR;
 270         termios.c_cflag |= CREAD;
 271         termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
 272
 273         termios.c_cc[VINTR]    =   03;  /* ^C */
 274         termios.c_cc[VQUIT]    =  034;  /* ^\ */
 275         termios.c_cc[VERASE]   = 0177;
 276         termios.c_cc[VKILL]    =  025;  /* ^X */
 277         termios.c_cc[VEOF]     =   04;  /* ^D */
 278         termios.c_cc[VSTART]   =  021;  /* ^Q */
 279         termios.c_cc[VSTOP]    =  023;  /* ^S */
 280         termios.c_cc[VSUSP]    =  032;  /* ^Z */
 281         termios.c_cc[VLNEXT]   =  026;  /* ^V */
 282         termios.c_cc[VWERASE]  =  027;  /* ^W */
 283         termios.c_cc[VREPRINT] =  022;  /* ^R */
 284         termios.c_cc[VEOL]     =    0;
 285         termios.c_cc[VEOL2]    =    0;
 286
 287         termios.c_cc[VTIME]  = 0;
 288         termios.c_cc[VMIN]   = 1;
 289
 290         if (tcsetattr(fd, TCSANOW, &termios) < 0)
 291                 r = -errno;
 292
 293 finish:
 294         /* Just in case, flush all crap out */
 295         (void) tcflush(fd, TCIOFLUSH);
 296
 297         return r;
 298 }
 299
 300 int reset_terminal(const char *name) {
 301         _cleanup_close_ int fd = -1;
 302
 303         /* We open the terminal with O_NONBLOCK here, to ensure we
 304          * don't block on carrier if this is a terminal with carrier
 305          * configured. */
 306
 307         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 308         if (fd < 0)
 309                 return fd;
 310
 311         return reset_terminal_fd(fd, true);
 312 }
 313
 314 int open_terminal(const char *name, int mode) {
 315         unsigned c = 0;
 316         int fd;
 317
 318         /*
 319          * If a TTY is in the process of being closed opening it might
 320          * cause EIO. This is horribly awful, but unlikely to be
 321          * changed in the kernel. Hence we work around this problem by
 322          * retrying a couple of times.
 323          *
 324          * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
 325          */
 326
 327         if (mode & O_CREAT)
 328                 return -EINVAL;
 329
 330         for (;;) {
 331                 fd = open(name, mode, 0);
 332                 if (fd >= 0)
 333                         break;
 334
 335                 if (errno != EIO)
 336                         return -errno;
 337
 338                 /* Max 1s in total */
 339                 if (c >= 20)
 340                         return -errno;
 341
 342                 usleep(50 * USEC_PER_MSEC);
 343                 c++;
 344         }
 345
 346         if (isatty(fd) <= 0) {
 347                 safe_close(fd);
 348                 return -ENOTTY;
 349         }
 350
 351         return fd;
 352 }
 353
 354 int acquire_terminal(
 355                 const char *name,
 356                 AcquireTerminalFlags flags,
 357                 usec_t timeout) {
 358
 359         _cleanup_close_ int notify = -1, fd = -1;
 360         usec_t ts = USEC_INFINITY;
 361         int r, wd = -1;
 362
 363         assert(name);
 364         assert(IN_SET(flags & ~ACQUIRE_TERMINAL_PERMISSIVE, ACQUIRE_TERMINAL_TRY, ACQUIRE_TERMINAL_FORCE, ACQUIRE_TERMINAL_WAIT));
 365
 366         /* We use inotify to be notified when the tty is closed. We create the watch before checking if we can actually
 367          * acquire it, so that we don't lose any event.
 368          *
 369          * Note: strictly speaking this actually watches for the device being closed, it does *not* really watch
 370          * whether a tty loses its controlling process. However, unless some rogue process uses TIOCNOTTY on /dev/tty
 371          * *after* closing its tty otherwise this will not become a problem. As long as the administrator makes sure to
 372          * not configure any service on the same tty as an untrusted user this should not be a problem. (Which they
 373          * probably should not do anyway.) */
 374
 375         if ((flags & ~ACQUIRE_TERMINAL_PERMISSIVE) == ACQUIRE_TERMINAL_WAIT) {
 376                 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
 377                 if (notify < 0)
 378                         return -errno;
 379
 380                 wd = inotify_add_watch(notify, name, IN_CLOSE);
 381                 if (wd < 0)
 382                         return -errno;
 383
 384                 if (timeout != USEC_INFINITY)
 385                         ts = now(CLOCK_MONOTONIC);
 386         }
 387
 388         for (;;) {
 389                 struct sigaction sa_old, sa_new = {
 390                         .sa_handler = SIG_IGN,
 391                         .sa_flags = SA_RESTART,
 392                 };
 393
 394                 if (notify >= 0) {
 395                         r = flush_fd(notify);
 396                         if (r < 0)
 397                                 return r;
 398                 }
 399
 400                 /* We pass here O_NOCTTY only so that we can check the return value TIOCSCTTY and have a reliable way
 401                  * to figure out if we successfully became the controlling process of the tty */
 402                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 403                 if (fd < 0)
 404                         return fd;
 405
 406                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed if we already own the tty. */
 407                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 408
 409                 /* First, try to get the tty */
 410                 r = ioctl(fd, TIOCSCTTY,
 411                           (flags & ~ACQUIRE_TERMINAL_PERMISSIVE) == ACQUIRE_TERMINAL_FORCE) < 0 ? -errno : 0;
 412
 413                 /* Reset signal handler to old value */
 414                 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 415
 416                 /* Success? Exit the loop now! */
 417                 if (r >= 0)
 418                         break;
 419
 420                 /* Any failure besides -EPERM? Fail, regardless of the mode. */
 421                 if (r != -EPERM)
 422                         return r;
 423
 424                 if (flags & ACQUIRE_TERMINAL_PERMISSIVE) /* If we are in permissive mode, then EPERM is fine, turn this
 425                                                           * into a success. Note that EPERM is also returned if we
 426                                                           * already are the owner of the TTY. */
 427                         break;
 428
 429                 if (flags != ACQUIRE_TERMINAL_WAIT) /* If we are in TRY or FORCE mode, then propagate EPERM as EPERM */
 430                         return r;
 431
 432                 assert(notify >= 0);
 433                 assert(wd >= 0);
 434
 435                 for (;;) {
 436                         union inotify_event_buffer buffer;
 437                         struct inotify_event *e;
 438                         ssize_t l;
 439
 440                         if (timeout != USEC_INFINITY) {
 441                                 usec_t n;
 442
 443                                 assert(ts != USEC_INFINITY);
 444
 445                                 n = now(CLOCK_MONOTONIC);
 446                                 if (ts + timeout < n)
 447                                         return -ETIMEDOUT;
 448
 449                                 r = fd_wait_for_event(notify, POLLIN, ts + timeout - n);
 450                                 if (r < 0)
 451                                         return r;
 452                                 if (r == 0)
 453                                         return -ETIMEDOUT;
 454                         }
 455
 456                         l = read(notify, &buffer, sizeof(buffer));
 457                         if (l < 0) {
 458                                 if (IN_SET(errno, EINTR, EAGAIN))
 459                                         continue;
 460
 461                                 return -errno;
 462                         }
 463
 464                         FOREACH_INOTIFY_EVENT(e, buffer, l) {
 465                                 if (e->mask & IN_Q_OVERFLOW) /* If we hit an inotify queue overflow, simply check if the terminal is up for grabs now. */
 466                                         break;
 467
 468                                 if (e->wd != wd || !(e->mask & IN_CLOSE)) /* Safety checks */
 469                                         return -EIO;
 470                         }
 471
 472                         break;
 473                 }
 474
 475                 /* We close the tty fd here since if the old session ended our handle will be dead. It's important that
 476                  * we do this after sleeping, so that we don't enter an endless loop. */
 477                 fd = safe_close(fd);
 478         }
 479
 480         return TAKE_FD(fd);
 481 }
 482
 483 int release_terminal(void) {
 484         static const struct sigaction sa_new = {
 485                 .sa_handler = SIG_IGN,
 486                 .sa_flags = SA_RESTART,
 487         };
 488
 489         _cleanup_close_ int fd = -1;
 490         struct sigaction sa_old;
 491         int r;
 492
 493         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 494         if (fd < 0)
 495                 return -errno;
 496
 497         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 498          * by our own TIOCNOTTY */
 499         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 500
 501         r = ioctl(fd, TIOCNOTTY) < 0 ? -errno : 0;
 502
 503         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 504
 505         return r;
 506 }
 507
 508 int terminal_vhangup_fd(int fd) {
 509         assert(fd >= 0);
 510
 511         if (ioctl(fd, TIOCVHANGUP) < 0)
 512                 return -errno;
 513
 514         return 0;
 515 }
 516
 517 int terminal_vhangup(const char *name) {
 518         _cleanup_close_ int fd;
 519
 520         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 521         if (fd < 0)
 522                 return fd;
 523
 524         return terminal_vhangup_fd(fd);
 525 }
 526
 527 int vt_disallocate(const char *name) {
 528         _cleanup_close_ int fd = -1;
 529         const char *e, *n;
 530         unsigned u;
 531         int r;
 532
 533         /* Deallocate the VT if possible. If not possible
 534          * (i.e. because it is the active one), at least clear it
 535          * entirely (including the scrollback buffer) */
 536
 537         e = path_startswith(name, "/dev/");
 538         if (!e)
 539                 return -EINVAL;
 540
 541         if (!tty_is_vc(name)) {
 542                 /* So this is not a VT. I guess we cannot deallocate
 543                  * it then. But let's at least clear the screen */
 544
 545                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 546                 if (fd < 0)
 547                         return fd;
 548
 549                 loop_write(fd,
 550                            "\033[r"    /* clear scrolling region */
 551                            "\033[H"    /* move home */
 552                            "\033[2J",  /* clear screen */
 553                            10, false);
 554                 return 0;
 555         }
 556
 557         n = startswith(e, "tty");
 558         if (!n)
 559                 return -EINVAL;
 560
 561         r = safe_atou(n, &u);
 562         if (r < 0)
 563                 return r;
 564
 565         if (u <= 0)
 566                 return -EINVAL;
 567
 568         /* Try to deallocate */
 569         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 570         if (fd < 0)
 571                 return fd;
 572
 573         r = ioctl(fd, VT_DISALLOCATE, u);
 574         fd = safe_close(fd);
 575
 576         if (r >= 0)
 577                 return 0;
 578
 579         if (errno != EBUSY)
 580                 return -errno;
 581
 582         /* Couldn't deallocate, so let's clear it fully with
 583          * scrollback */
 584         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 585         if (fd < 0)
 586                 return fd;
 587
 588         loop_write(fd,
 589                    "\033[r"   /* clear scrolling region */
 590                    "\033[H"   /* move home */
 591                    "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
 592                    10, false);
 593         return 0;
 594 }
 595
 596 int make_console_stdio(void) {
 597         int fd, r;
 598
 599         /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
 600
 601         fd = acquire_terminal("/dev/console", ACQUIRE_TERMINAL_FORCE|ACQUIRE_TERMINAL_PERMISSIVE, USEC_INFINITY);
 602         if (fd < 0)
 603                 return log_error_errno(fd, "Failed to acquire terminal: %m");
 604
 605         r = reset_terminal_fd(fd, true);
 606         if (r < 0)
 607                 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
 608
 609         r = rearrange_stdio(fd, fd, fd); /* This invalidates 'fd' both on success and on failure. */
 610         if (r < 0)
 611                 return log_error_errno(r, "Failed to make terminal stdin/stdout/stderr: %m");
 612
 613         reset_terminal_feature_caches();
 614
 615         return 0;
 616 }
 617
 618 bool tty_is_vc(const char *tty) {
 619         assert(tty);
 620
 621         return vtnr_from_tty(tty) >= 0;
 622 }
 623
 624 bool tty_is_console(const char *tty) {
 625         assert(tty);
 626
 627         return streq(skip_dev_prefix(tty), "console");
 628 }
 629
 630 int vtnr_from_tty(const char *tty) {
 631         int i, r;
 632
 633         assert(tty);
 634
 635         tty = skip_dev_prefix(tty);
 636
 637         if (!startswith(tty, "tty") )
 638                 return -EINVAL;
 639
 640         if (tty[3] < '0' || tty[3] > '9')
 641                 return -EINVAL;
 642
 643         r = safe_atoi(tty+3, &i);
 644         if (r < 0)
 645                 return r;
 646
 647         if (i < 0 || i > 63)
 648                 return -EINVAL;
 649
 650         return i;
 651 }
 652
 653  int resolve_dev_console(char **ret) {
 654         _cleanup_free_ char *active = NULL;
 655         char *tty;
 656         int r;
 657
 658         assert(ret);
 659
 660         /* Resolve where /dev/console is pointing to, if /sys is actually ours (i.e. not read-only-mounted which is a
 661          * sign for container setups) */
 662
 663         if (path_is_read_only_fs("/sys") > 0)
 664                 return -ENOMEDIUM;
 665
 666         r = read_one_line_file("/sys/class/tty/console/active", &active);
 667         if (r < 0)
 668                 return r;
 669
 670         /* If multiple log outputs are configured the last one is what /dev/console points to */
 671         tty = strrchr(active, ' ');
 672         if (tty)
 673                 tty++;
 674         else
 675                 tty = active;
 676
 677         if (streq(tty, "tty0")) {
 678                 active = mfree(active);
 679
 680                 /* Get the active VC (e.g. tty1) */
 681                 r = read_one_line_file("/sys/class/tty/tty0/active", &active);
 682                 if (r < 0)
 683                         return r;
 684
 685                 tty = active;
 686         }
 687
 688         if (tty == active)
 689                 *ret = TAKE_PTR(active);
 690         else {
 691                 char *tmp;
 692
 693                 tmp = strdup(tty);
 694                 if (!tmp)
 695                         return -ENOMEM;
 696
 697                 *ret = tmp;
 698         }
 699
 700         return 0;
 701 }
 702
 703 int get_kernel_consoles(char ***ret) {
 704         _cleanup_strv_free_ char **l = NULL;
 705         _cleanup_free_ char *line = NULL;
 706         const char *p;
 707         int r;
 708
 709         assert(ret);
 710
 711         /* If /sys is mounted read-only this means we are running in some kind of container environment. In that
 712          * case /sys would reflect the host system, not us, hence ignore the data we can read from it. */
 713         if (path_is_read_only_fs("/sys") > 0)
 714                 goto fallback;
 715
 716         r = read_one_line_file("/sys/class/tty/console/active", &line);
 717         if (r < 0)
 718                 return r;
 719
 720         p = line;
 721         for (;;) {
 722                 _cleanup_free_ char *tty = NULL;
 723                 char *path;
 724
 725                 r = extract_first_word(&p, &tty, NULL, 0);
 726                 if (r < 0)
 727                         return r;
 728                 if (r == 0)
 729                         break;
 730
 731                 if (streq(tty, "tty0")) {
 732                         tty = mfree(tty);
 733                         r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
 734                         if (r < 0)
 735                                 return r;
 736                 }
 737
 738                 path = strappend("/dev/", tty);
 739                 if (!path)
 740                         return -ENOMEM;
 741
 742                 if (access(path, F_OK) < 0) {
 743                         log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
 744                         free(path);
 745                         continue;
 746                 }
 747
 748                 r = strv_consume(&l, path);
 749                 if (r < 0)
 750                         return r;
 751         }
 752
 753         if (strv_isempty(l)) {
 754                 log_debug("No devices found for system console");
 755                 goto fallback;
 756         }
 757
 758         *ret = TAKE_PTR(l);
 759
 760         return 0;
 761
 762 fallback:
 763         r = strv_extend(&l, "/dev/console");
 764         if (r < 0)
 765                 return r;
 766
 767         *ret = TAKE_PTR(l);
 768
 769         return 0;
 770 }
 771
 772 bool tty_is_vc_resolve(const char *tty) {
 773         _cleanup_free_ char *resolved = NULL;
 774
 775         assert(tty);
 776
 777         tty = skip_dev_prefix(tty);
 778
 779         if (streq(tty, "console")) {
 780                 if (resolve_dev_console(&resolved) < 0)
 781                         return false;
 782
 783                 tty = resolved;
 784         }
 785
 786         return tty_is_vc(tty);
 787 }
 788
 789 const char *default_term_for_tty(const char *tty) {
 790         return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220";
 791 }
 792
 793 int fd_columns(int fd) {
 794         struct winsize ws = {};
 795
 796         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 797                 return -errno;
 798
 799         if (ws.ws_col <= 0)
 800                 return -EIO;
 801
 802         return ws.ws_col;
 803 }
 804
 805 unsigned columns(void) {
 806         const char *e;
 807         int c;
 808
 809         if (cached_columns > 0)
 810                 return cached_columns;
 811
 812         c = 0;
 813         e = getenv("COLUMNS");
 814         if (e)
 815                 (void) safe_atoi(e, &c);
 816
 817         if (c <= 0 || c > USHRT_MAX) {
 818                 c = fd_columns(STDOUT_FILENO);
 819                 if (c <= 0)
 820                         c = 80;
 821         }
 822
 823         cached_columns = c;
 824         return cached_columns;
 825 }
 826
 827 int fd_lines(int fd) {
 828         struct winsize ws = {};
 829
 830         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 831                 return -errno;
 832
 833         if (ws.ws_row <= 0)
 834                 return -EIO;
 835
 836         return ws.ws_row;
 837 }
 838
 839 unsigned lines(void) {
 840         const char *e;
 841         int l;
 842
 843         if (cached_lines > 0)
 844                 return cached_lines;
 845
 846         l = 0;
 847         e = getenv("LINES");
 848         if (e)
 849                 (void) safe_atoi(e, &l);
 850
 851         if (l <= 0 || l > USHRT_MAX) {
 852                 l = fd_lines(STDOUT_FILENO);
 853                 if (l <= 0)
 854                         l = 24;
 855         }
 856
 857         cached_lines = l;
 858         return cached_lines;
 859 }
 860
 861 /* intended to be used as a SIGWINCH sighandler */
 862 void columns_lines_cache_reset(int signum) {
 863         cached_columns = 0;
 864         cached_lines = 0;
 865 }
 866
 867 void reset_terminal_feature_caches(void) {
 868         cached_columns = 0;
 869         cached_lines = 0;
 870
 871         cached_colors_enabled = -1;
 872         cached_underline_enabled = -1;
 873         cached_on_tty = -1;
 874 }
 875
 876 bool on_tty(void) {
 877
 878         /* We check both stdout and stderr, so that situations where pipes on the shell are used are reliably
 879          * recognized, regardless if only the output or the errors are piped to some place. Since on_tty() is generally
 880          * used to default to a safer, non-interactive, non-color mode of operation it's probably good to be defensive
 881          * here, and check for both. Note that we don't check for STDIN_FILENO, because it should fine to use fancy
 882          * terminal functionality when outputting stuff, even if the input is piped to us. */
 883
 884         if (cached_on_tty < 0)
 885                 cached_on_tty =
 886                         isatty(STDOUT_FILENO) > 0 &&
 887                         isatty(STDERR_FILENO) > 0;
 888
 889         return cached_on_tty;
 890 }
 891
 892 int getttyname_malloc(int fd, char **ret) {
 893         size_t l = 100;
 894         int r;
 895
 896         assert(fd >= 0);
 897         assert(ret);
 898
 899         for (;;) {
 900                 char path[l];
 901
 902                 r = ttyname_r(fd, path, sizeof(path));
 903                 if (r == 0) {
 904                         char *c;
 905
 906                         c = strdup(skip_dev_prefix(path));
 907                         if (!c)
 908                                 return -ENOMEM;
 909
 910                         *ret = c;
 911                         return 0;
 912                 }
 913
 914                 if (r != ERANGE)
 915                         return -r;
 916
 917                 l *= 2;
 918         }
 919
 920         return 0;
 921 }
 922
 923 int getttyname_harder(int fd, char **r) {
 924         int k;
 925         char *s = NULL;
 926
 927         k = getttyname_malloc(fd, &s);
 928         if (k < 0)
 929                 return k;
 930
 931         if (streq(s, "tty")) {
 932                 free(s);
 933                 return get_ctty(0, NULL, r);
 934         }
 935
 936         *r = s;
 937         return 0;
 938 }
 939
 940 int get_ctty_devnr(pid_t pid, dev_t *d) {
 941         int r;
 942         _cleanup_free_ char *line = NULL;
 943         const char *p;
 944         unsigned long ttynr;
 945
 946         assert(pid >= 0);
 947
 948         p = procfs_file_alloca(pid, "stat");
 949         r = read_one_line_file(p, &line);
 950         if (r < 0)
 951                 return r;
 952
 953         p = strrchr(line, ')');
 954         if (!p)
 955                 return -EIO;
 956
 957         p++;
 958
 959         if (sscanf(p, " "
 960                    "%*c "  /* state */
 961                    "%*d "  /* ppid */
 962                    "%*d "  /* pgrp */
 963                    "%*d "  /* session */
 964                    "%lu ", /* ttynr */
 965                    &ttynr) != 1)
 966                 return -EIO;
 967
 968         if (major(ttynr) == 0 && minor(ttynr) == 0)
 969                 return -ENXIO;
 970
 971         if (d)
 972                 *d = (dev_t) ttynr;
 973
 974         return 0;
 975 }
 976
 977 int get_ctty(pid_t pid, dev_t *ret_devnr, char **ret) {
 978         _cleanup_free_ char *fn = NULL, *b = NULL;
 979         dev_t devnr;
 980         int r;
 981
 982         r = get_ctty_devnr(pid, &devnr);
 983         if (r < 0)
 984                 return r;
 985
 986         r = device_path_make_canonical(S_IFCHR, devnr, &fn);
 987         if (r < 0) {
 988                 if (r != -ENOENT) /* No symlink for this in /dev/char/? */
 989                         return r;
 990
 991                 if (major(devnr) == 136) {
 992                         /* This is an ugly hack: PTY devices are not listed in /dev/char/, as they don't follow the
 993                          * Linux device model. This means we have no nice way to match them up against their actual
 994                          * device node. Let's hence do the check by the fixed, assigned major number. Normally we try
 995                          * to avoid such fixed major/minor matches, but there appears to nother nice way to handle
 996                          * this. */
 997
 998                         if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
 999                                 return -ENOMEM;
1000                 } else {
1001                         /* Probably something similar to the ptys which have no symlink in /dev/char/. Let's return
1002                          * something vaguely useful. */
1003
1004                         r = device_path_make_major_minor(S_IFCHR, devnr, &fn);
1005                         if (r < 0)
1006                                 return r;
1007                 }
1008         }
1009
1010         if (!b) {
1011                 const char *w;
1012
1013                 w = path_startswith(fn, "/dev/");
1014                 if (w) {
1015                         b = strdup(w);
1016                         if (!b)
1017                                 return -ENOMEM;
1018                 } else
1019                         b = TAKE_PTR(fn);
1020         }
1021
1022         if (ret)
1023                 *ret = TAKE_PTR(b);
1024
1025         if (ret_devnr)
1026                 *ret_devnr = devnr;
1027
1028         return 0;
1029 }
1030
1031 int ptsname_malloc(int fd, char **ret) {
1032         size_t l = 100;
1033
1034         assert(fd >= 0);
1035         assert(ret);
1036
1037         for (;;) {
1038                 char *c;
1039
1040                 c = new(char, l);
1041                 if (!c)
1042                         return -ENOMEM;
1043
1044                 if (ptsname_r(fd, c, l) == 0) {
1045                         *ret = c;
1046                         return 0;
1047                 }
1048                 if (errno != ERANGE) {
1049                         free(c);
1050                         return -errno;
1051                 }
1052
1053                 free(c);
1054                 l *= 2;
1055         }
1056 }
1057
1058 int ptsname_namespace(int pty, char **ret) {
1059         int no = -1, r;
1060
1061         /* Like ptsname(), but doesn't assume that the path is
1062          * accessible in the local namespace. */
1063
1064         r = ioctl(pty, TIOCGPTN, &no);
1065         if (r < 0)
1066                 return -errno;
1067
1068         if (no < 0)
1069                 return -EIO;
1070
1071         if (asprintf(ret, "/dev/pts/%i", no) < 0)
1072                 return -ENOMEM;
1073
1074         return 0;
1075 }
1076
1077 int openpt_in_namespace(pid_t pid, int flags) {
1078         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1079         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1080         pid_t child;
1081         int r;
1082
1083         assert(pid > 0);
1084
1085         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1086         if (r < 0)
1087                 return r;
1088
1089         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1090                 return -errno;
1091
1092         r = namespace_fork("(sd-openptns)", "(sd-openpt)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG,
1093                            pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child);
1094         if (r < 0)
1095                 return r;
1096         if (r == 0) {
1097                 int master;
1098
1099                 pair[0] = safe_close(pair[0]);
1100
1101                 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1102                 if (master < 0)
1103                         _exit(EXIT_FAILURE);
1104
1105                 if (unlockpt(master) < 0)
1106                         _exit(EXIT_FAILURE);
1107
1108                 if (send_one_fd(pair[1], master, 0) < 0)
1109                         _exit(EXIT_FAILURE);
1110
1111                 _exit(EXIT_SUCCESS);
1112         }
1113
1114         pair[1] = safe_close(pair[1]);
1115
1116         r = wait_for_terminate_and_check("(sd-openptns)", child, 0);
1117         if (r < 0)
1118                 return r;
1119         if (r != EXIT_SUCCESS)
1120                 return -EIO;
1121
1122         return receive_one_fd(pair[0], 0);
1123 }
1124
1125 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1126         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1127         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1128         pid_t child;
1129         int r;
1130
1131         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1132         if (r < 0)
1133                 return r;
1134
1135         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1136                 return -errno;
1137
1138         r = namespace_fork("(sd-terminalns)", "(sd-terminal)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG,
1139                            pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child);
1140         if (r < 0)
1141                 return r;
1142         if (r == 0) {
1143                 int master;
1144
1145                 pair[0] = safe_close(pair[0]);
1146
1147                 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1148                 if (master < 0)
1149                         _exit(EXIT_FAILURE);
1150
1151                 if (send_one_fd(pair[1], master, 0) < 0)
1152                         _exit(EXIT_FAILURE);
1153
1154                 _exit(EXIT_SUCCESS);
1155         }
1156
1157         pair[1] = safe_close(pair[1]);
1158
1159         r = wait_for_terminate_and_check("(sd-terminalns)", child, 0);
1160         if (r < 0)
1161                 return r;
1162         if (r != EXIT_SUCCESS)
1163                 return -EIO;
1164
1165         return receive_one_fd(pair[0], 0);
1166 }
1167
1168 static bool getenv_terminal_is_dumb(void) {
1169         const char *e;
1170
1171         e = getenv("TERM");
1172         if (!e)
1173                 return true;
1174
1175         return streq(e, "dumb");
1176 }
1177
1178 bool terminal_is_dumb(void) {
1179         if (!on_tty())
1180                 return true;
1181
1182         return getenv_terminal_is_dumb();
1183 }
1184
1185 bool colors_enabled(void) {
1186
1187         /* Returns true if colors are considered supported on our stdout. For that we check $SYSTEMD_COLORS first
1188          * (which is the explicit way to turn colors on/off). If that didn't work we turn colors off unless we are on a
1189          * TTY. And if we are on a TTY we turn it off if $TERM is set to "dumb". There's one special tweak though: if
1190          * we are PID 1 then we do not check whether we are connected to a TTY, because we don't keep /dev/console open
1191          * continously due to fear of SAK, and hence things are a bit weird. */
1192
1193         if (cached_colors_enabled < 0) {
1194                 int val;
1195
1196                 val = getenv_bool("SYSTEMD_COLORS");
1197                 if (val >= 0)
1198                         cached_colors_enabled = val;
1199                 else if (getpid_cached() == 1)
1200                         /* PID1 outputs to the console without holding it open all the time */
1201                         cached_colors_enabled = !getenv_terminal_is_dumb();
1202                 else
1203                         cached_colors_enabled = !terminal_is_dumb();
1204         }
1205
1206         return cached_colors_enabled;
1207 }
1208
1209 bool dev_console_colors_enabled(void) {
1210         _cleanup_free_ char *s = NULL;
1211         int b;
1212
1213         /* Returns true if we assume that color is supported on /dev/console.
1214          *
1215          * For that we first check if we explicitly got told to use colors or not, by checking $SYSTEMD_COLORS. If that
1216          * isn't set we check whether PID 1 has $TERM set, and if not, whether TERM is set on the kernel command
1217          * line. If we find $TERM set we assume color if it's not set to "dumb", similarly to how regular
1218          * colors_enabled() operates. */
1219
1220         b = getenv_bool("SYSTEMD_COLORS");
1221         if (b >= 0)
1222                 return b;
1223
1224         if (getenv_for_pid(1, "TERM", &s) <= 0)
1225                 (void) proc_cmdline_get_key("TERM", 0, &s);
1226
1227         return !streq_ptr(s, "dumb");
1228 }
1229
1230 bool underline_enabled(void) {
1231
1232         if (cached_underline_enabled < 0) {
1233
1234                 /* The Linux console doesn't support underlining, turn it off, but only there. */
1235
1236                 if (colors_enabled())
1237                         cached_underline_enabled = !streq_ptr(getenv("TERM"), "linux");
1238                 else
1239                         cached_underline_enabled = false;
1240         }
1241
1242         return cached_underline_enabled;
1243 }
1244
1245 int vt_default_utf8(void) {
1246         _cleanup_free_ char *b = NULL;
1247         int r;
1248
1249         /* Read the default VT UTF8 setting from the kernel */
1250
1251         r = read_one_line_file("/sys/module/vt/parameters/default_utf8", &b);
1252         if (r < 0)
1253                 return r;
1254
1255         return parse_boolean(b);
1256 }
1257
1258 int vt_reset_keyboard(int fd) {
1259         int kb;
1260
1261         /* If we can't read the default, then default to unicode. It's 2017 after all. */
1262         kb = vt_default_utf8() != 0 ? K_UNICODE : K_XLATE;
1263
1264         if (ioctl(fd, KDSKBMODE, kb) < 0)
1265                 return -errno;
1266
1267         return 0;
1268 }
1269
1270 int vt_restore(int fd) {
1271         static const struct vt_mode mode = {
1272                 .mode = VT_AUTO,
1273         };
1274         int r, q = 0;
1275
1276         r = ioctl(fd, KDSETMODE, KD_TEXT);
1277         if (r < 0)
1278                 q = log_debug_errno(errno, "Failed to set VT in text mode, ignoring: %m");
1279
1280         r = vt_reset_keyboard(fd);
1281         if (r < 0) {
1282                 log_debug_errno(r, "Failed to reset keyboard mode, ignoring: %m");
1283                 if (q >= 0)
1284                         q = r;
1285         }
1286
1287         r = ioctl(fd, VT_SETMODE, &mode);
1288         if (r < 0) {
1289                 log_debug_errno(errno, "Failed to set VT_AUTO mode, ignoring: %m");
1290                 if (q >= 0)
1291                         q = -errno;
1292         }
1293
1294         r = fchown(fd, 0, (gid_t) -1);
1295         if (r < 0) {
1296                 log_debug_errno(errno, "Failed to chown VT, ignoring: %m");
1297                 if (q >= 0)
1298                         q = -errno;
1299         }
1300
1301         return q;
1302 }
1303
1304 int vt_release(int fd, bool restore) {
1305         assert(fd >= 0);
1306
1307         /* This function releases the VT by acknowledging the VT-switch signal
1308          * sent by the kernel and optionally reset the VT in text and auto
1309          * VT-switching modes. */
1310
1311         if (ioctl(fd, VT_RELDISP, 1) < 0)
1312                 return -errno;
1313
1314         if (restore)
1315                 return vt_restore(fd);
1316
1317         return 0;
1318 }