src/basic/terminal-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   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 <sys/inotify.h>
  15 #include <sys/ioctl.h>
  16 #include <sys/sysmacros.h>
  17 #include <sys/time.h>
  18 #include <sys/types.h>
  19 #include <sys/utsname.h>
  20 #include <termios.h>
  21 #include <unistd.h>
  22
  23 #include "alloc-util.h"
  24 #include "copy.h"
  25 #include "def.h"
  26 #include "env-util.h"
  27 #include "fd-util.h"
  28 #include "fileio.h"
  29 #include "fs-util.h"
  30 #include "io-util.h"
  31 #include "log.h"
  32 #include "macro.h"
  33 #include "namespace-util.h"
  34 #include "parse-util.h"
  35 #include "path-util.h"
  36 #include "proc-cmdline.h"
  37 #include "process-util.h"
  38 #include "socket-util.h"
  39 #include "stat-util.h"
  40 #include "string-util.h"
  41 #include "strv.h"
  42 #include "terminal-util.h"
  43 #include "time-util.h"
  44 #include "user-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_color_mode = _COLOR_INVALID;
  52 static volatile int cached_underline_enabled = -1;
  53
  54 int chvt(int vt) {
  55         _cleanup_close_ int fd = -1;
  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, fd;
  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
  91          * character. (Note that fmemopen() streams do not have an fd associated with them, let's handle that
  92          * nicely.) */
  93         fd = fileno(f);
  94         if (fd >= 0 && tcgetattr(fd, &old_termios) >= 0) {
  95                 struct termios 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(fd, TCSADRAIN, &new_termios) >= 0) {
 102                         char c;
 103
 104                         if (t != USEC_INFINITY) {
 105                                 if (fd_wait_for_event(fd, POLLIN, t) <= 0) {
 106                                         (void) tcsetattr(fd, TCSADRAIN, &old_termios);
 107                                         return -ETIMEDOUT;
 108                                 }
 109                         }
 110
 111                         r = safe_fgetc(f, &c);
 112                         (void) tcsetattr(fd, TCSADRAIN, &old_termios);
 113                         if (r < 0)
 114                                 return r;
 115                         if (r == 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 && fd > 0) {
 127                 /* Let's wait the specified amount of time for input. When we have no fd we skip this, under
 128                  * the assumption that this is an fmemopen() stream or so where waiting doesn't make sense
 129                  * anyway, as the data is either already in the stream or cannot possible be placed there
 130                  * while we access the stream */
 131
 132                 if (fd_wait_for_event(fd, POLLIN, t) <= 0)
 133                         return -ETIMEDOUT;
 134         }
 135
 136         /* If this is not a terminal, then read a full line instead */
 137
 138         r = read_line(f, 16, &line); /* longer than necessary, to eat up UTF-8 chars/vt100 key sequences */
 139         if (r < 0)
 140                 return r;
 141         if (r == 0)
 142                 return -EIO;
 143
 144         if (strlen(line) != 1)
 145                 return -EBADMSG;
 146
 147         if (need_nl)
 148                 *need_nl = false;
 149
 150         *ret = line[0];
 151         return 0;
 152 }
 153
 154 #define DEFAULT_ASK_REFRESH_USEC (2*USEC_PER_SEC)
 155
 156 int ask_char(char *ret, const char *replies, const char *fmt, ...) {
 157         int r;
 158
 159         assert(ret);
 160         assert(replies);
 161         assert(fmt);
 162
 163         for (;;) {
 164                 va_list ap;
 165                 char c;
 166                 bool need_nl = true;
 167
 168                 fputs(ansi_highlight(), stdout);
 169
 170                 putchar('\r');
 171
 172                 va_start(ap, fmt);
 173                 vprintf(fmt, ap);
 174                 va_end(ap);
 175
 176                 fputs(ansi_normal(), stdout);
 177
 178                 fflush(stdout);
 179
 180                 r = read_one_char(stdin, &c, DEFAULT_ASK_REFRESH_USEC, &need_nl);
 181                 if (r < 0) {
 182
 183                         if (r == -ETIMEDOUT)
 184                                 continue;
 185
 186                         if (r == -EBADMSG) {
 187                                 puts("Bad input, please try again.");
 188                                 continue;
 189                         }
 190
 191                         putchar('\n');
 192                         return r;
 193                 }
 194
 195                 if (need_nl)
 196                         putchar('\n');
 197
 198                 if (strchr(replies, c)) {
 199                         *ret = c;
 200                         return 0;
 201                 }
 202
 203                 puts("Read unexpected character, please try again.");
 204         }
 205 }
 206
 207 int ask_string(char **ret, const char *text, ...) {
 208         _cleanup_free_ char *line = NULL;
 209         va_list ap;
 210         int r;
 211
 212         assert(ret);
 213         assert(text);
 214
 215         fputs(ansi_highlight(), stdout);
 216
 217         va_start(ap, text);
 218         vprintf(text, ap);
 219         va_end(ap);
 220
 221         fputs(ansi_normal(), stdout);
 222
 223         fflush(stdout);
 224
 225         r = read_line(stdin, LONG_LINE_MAX, &line);
 226         if (r < 0)
 227                 return r;
 228         if (r == 0)
 229                 return -EIO;
 230
 231         *ret = TAKE_PTR(line);
 232         return 0;
 233 }
 234
 235 int reset_terminal_fd(int fd, bool switch_to_text) {
 236         struct termios termios;
 237         int r = 0;
 238
 239         /* Set terminal to some sane defaults */
 240
 241         assert(fd >= 0);
 242
 243         if (isatty(fd) < 1)
 244                 return log_debug_errno(errno, "Asked to reset a terminal that actually isn't a terminal: %m");
 245
 246         /* We leave locked terminal attributes untouched, so that Plymouth may set whatever it wants to set,
 247          * and we don't interfere with that. */
 248
 249         /* Disable exclusive mode, just in case */
 250         if (ioctl(fd, TIOCNXCL) < 0)
 251                 log_debug_errno(errno, "TIOCNXCL ioctl failed on TTY, ignoring: %m");
 252
 253         /* Switch to text mode */
 254         if (switch_to_text)
 255                 if (ioctl(fd, KDSETMODE, KD_TEXT) < 0)
 256                         log_debug_errno(errno, "KDSETMODE ioctl for switching to text mode failed on TTY, ignoring: %m");
 257
 258
 259         /* Set default keyboard mode */
 260         (void) vt_reset_keyboard(fd);
 261
 262         if (tcgetattr(fd, &termios) < 0) {
 263                 r = log_debug_errno(errno, "Failed to get terminal parameters: %m");
 264                 goto finish;
 265         }
 266
 267         /* We only reset the stuff that matters to the software. How
 268          * hardware is set up we don't touch assuming that somebody
 269          * else will do that for us */
 270
 271         termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
 272         termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
 273         termios.c_oflag |= ONLCR;
 274         termios.c_cflag |= CREAD;
 275         termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
 276
 277         termios.c_cc[VINTR]    =   03;  /* ^C */
 278         termios.c_cc[VQUIT]    =  034;  /* ^\ */
 279         termios.c_cc[VERASE]   = 0177;
 280         termios.c_cc[VKILL]    =  025;  /* ^X */
 281         termios.c_cc[VEOF]     =   04;  /* ^D */
 282         termios.c_cc[VSTART]   =  021;  /* ^Q */
 283         termios.c_cc[VSTOP]    =  023;  /* ^S */
 284         termios.c_cc[VSUSP]    =  032;  /* ^Z */
 285         termios.c_cc[VLNEXT]   =  026;  /* ^V */
 286         termios.c_cc[VWERASE]  =  027;  /* ^W */
 287         termios.c_cc[VREPRINT] =  022;  /* ^R */
 288         termios.c_cc[VEOL]     =    0;
 289         termios.c_cc[VEOL2]    =    0;
 290
 291         termios.c_cc[VTIME]  = 0;
 292         termios.c_cc[VMIN]   = 1;
 293
 294         if (tcsetattr(fd, TCSANOW, &termios) < 0)
 295                 r = -errno;
 296
 297 finish:
 298         /* Just in case, flush all crap out */
 299         (void) tcflush(fd, TCIOFLUSH);
 300
 301         return r;
 302 }
 303
 304 int reset_terminal(const char *name) {
 305         _cleanup_close_ int fd = -1;
 306
 307         /* We open the terminal with O_NONBLOCK here, to ensure we
 308          * don't block on carrier if this is a terminal with carrier
 309          * configured. */
 310
 311         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 312         if (fd < 0)
 313                 return fd;
 314
 315         return reset_terminal_fd(fd, true);
 316 }
 317
 318 int open_terminal(const char *name, int mode) {
 319         unsigned c = 0;
 320         int fd;
 321
 322         /*
 323          * If a TTY is in the process of being closed opening it might
 324          * cause EIO. This is horribly awful, but unlikely to be
 325          * changed in the kernel. Hence we work around this problem by
 326          * retrying a couple of times.
 327          *
 328          * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
 329          */
 330
 331         if (mode & O_CREAT)
 332                 return -EINVAL;
 333
 334         for (;;) {
 335                 fd = open(name, mode, 0);
 336                 if (fd >= 0)
 337                         break;
 338
 339                 if (errno != EIO)
 340                         return -errno;
 341
 342                 /* Max 1s in total */
 343                 if (c >= 20)
 344                         return -errno;
 345
 346                 usleep(50 * USEC_PER_MSEC);
 347                 c++;
 348         }
 349
 350         if (isatty(fd) <= 0) {
 351                 safe_close(fd);
 352                 return -ENOTTY;
 353         }
 354
 355         return fd;
 356 }
 357
 358 int acquire_terminal(
 359                 const char *name,
 360                 AcquireTerminalFlags flags,
 361                 usec_t timeout) {
 362
 363         _cleanup_close_ int notify = -1, fd = -1;
 364         usec_t ts = USEC_INFINITY;
 365         int r, wd = -1;
 366
 367         assert(name);
 368         assert(IN_SET(flags & ~ACQUIRE_TERMINAL_PERMISSIVE, ACQUIRE_TERMINAL_TRY, ACQUIRE_TERMINAL_FORCE, ACQUIRE_TERMINAL_WAIT));
 369
 370         /* We use inotify to be notified when the tty is closed. We create the watch before checking if we can actually
 371          * acquire it, so that we don't lose any event.
 372          *
 373          * Note: strictly speaking this actually watches for the device being closed, it does *not* really watch
 374          * whether a tty loses its controlling process. However, unless some rogue process uses TIOCNOTTY on /dev/tty
 375          * *after* closing its tty otherwise this will not become a problem. As long as the administrator makes sure to
 376          * not configure any service on the same tty as an untrusted user this should not be a problem. (Which they
 377          * probably should not do anyway.) */
 378
 379         if ((flags & ~ACQUIRE_TERMINAL_PERMISSIVE) == ACQUIRE_TERMINAL_WAIT) {
 380                 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
 381                 if (notify < 0)
 382                         return -errno;
 383
 384                 wd = inotify_add_watch(notify, name, IN_CLOSE);
 385                 if (wd < 0)
 386                         return -errno;
 387
 388                 if (timeout != USEC_INFINITY)
 389                         ts = now(CLOCK_MONOTONIC);
 390         }
 391
 392         for (;;) {
 393                 struct sigaction sa_old, sa_new = {
 394                         .sa_handler = SIG_IGN,
 395                         .sa_flags = SA_RESTART,
 396                 };
 397
 398                 if (notify >= 0) {
 399                         r = flush_fd(notify);
 400                         if (r < 0)
 401                                 return r;
 402                 }
 403
 404                 /* We pass here O_NOCTTY only so that we can check the return value TIOCSCTTY and have a reliable way
 405                  * to figure out if we successfully became the controlling process of the tty */
 406                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 407                 if (fd < 0)
 408                         return fd;
 409
 410                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed if we already own the tty. */
 411                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 412
 413                 /* First, try to get the tty */
 414                 r = ioctl(fd, TIOCSCTTY,
 415                           (flags & ~ACQUIRE_TERMINAL_PERMISSIVE) == ACQUIRE_TERMINAL_FORCE) < 0 ? -errno : 0;
 416
 417                 /* Reset signal handler to old value */
 418                 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 419
 420                 /* Success? Exit the loop now! */
 421                 if (r >= 0)
 422                         break;
 423
 424                 /* Any failure besides -EPERM? Fail, regardless of the mode. */
 425                 if (r != -EPERM)
 426                         return r;
 427
 428                 if (flags & ACQUIRE_TERMINAL_PERMISSIVE) /* If we are in permissive mode, then EPERM is fine, turn this
 429                                                           * into a success. Note that EPERM is also returned if we
 430                                                           * already are the owner of the TTY. */
 431                         break;
 432
 433                 if (flags != ACQUIRE_TERMINAL_WAIT) /* If we are in TRY or FORCE mode, then propagate EPERM as EPERM */
 434                         return r;
 435
 436                 assert(notify >= 0);
 437                 assert(wd >= 0);
 438
 439                 for (;;) {
 440                         union inotify_event_buffer buffer;
 441                         struct inotify_event *e;
 442                         ssize_t l;
 443
 444                         if (timeout != USEC_INFINITY) {
 445                                 usec_t n;
 446
 447                                 assert(ts != USEC_INFINITY);
 448
 449                                 n = usec_sub_unsigned(now(CLOCK_MONOTONIC), ts);
 450                                 if (n >= timeout)
 451                                         return -ETIMEDOUT;
 452
 453                                 r = fd_wait_for_event(notify, POLLIN, usec_sub_unsigned(timeout, n));
 454                                 if (r < 0)
 455                                         return r;
 456                                 if (r == 0)
 457                                         return -ETIMEDOUT;
 458                         }
 459
 460                         l = read(notify, &buffer, sizeof(buffer));
 461                         if (l < 0) {
 462                                 if (IN_SET(errno, EINTR, EAGAIN))
 463                                         continue;
 464
 465                                 return -errno;
 466                         }
 467
 468                         FOREACH_INOTIFY_EVENT(e, buffer, l) {
 469                                 if (e->mask & IN_Q_OVERFLOW) /* If we hit an inotify queue overflow, simply check if the terminal is up for grabs now. */
 470                                         break;
 471
 472                                 if (e->wd != wd || !(e->mask & IN_CLOSE)) /* Safety checks */
 473                                         return -EIO;
 474                         }
 475
 476                         break;
 477                 }
 478
 479                 /* We close the tty fd here since if the old session ended our handle will be dead. It's important that
 480                  * we do this after sleeping, so that we don't enter an endless loop. */
 481                 fd = safe_close(fd);
 482         }
 483
 484         return TAKE_FD(fd);
 485 }
 486
 487 int release_terminal(void) {
 488         static const struct sigaction sa_new = {
 489                 .sa_handler = SIG_IGN,
 490                 .sa_flags = SA_RESTART,
 491         };
 492
 493         _cleanup_close_ int fd = -1;
 494         struct sigaction sa_old;
 495         int r;
 496
 497         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 498         if (fd < 0)
 499                 return -errno;
 500
 501         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 502          * by our own TIOCNOTTY */
 503         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 504
 505         r = ioctl(fd, TIOCNOTTY) < 0 ? -errno : 0;
 506
 507         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 508
 509         return r;
 510 }
 511
 512 int terminal_vhangup_fd(int fd) {
 513         assert(fd >= 0);
 514
 515         if (ioctl(fd, TIOCVHANGUP) < 0)
 516                 return -errno;
 517
 518         return 0;
 519 }
 520
 521 int terminal_vhangup(const char *name) {
 522         _cleanup_close_ int fd = -1;
 523
 524         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 525         if (fd < 0)
 526                 return fd;
 527
 528         return terminal_vhangup_fd(fd);
 529 }
 530
 531 int vt_disallocate(const char *name) {
 532         const char *e;
 533         int r;
 534
 535         /* Deallocate the VT if possible. If not possible
 536          * (i.e. because it is the active one), at least clear it
 537          * entirely (including the scrollback buffer). */
 538
 539         e = path_startswith(name, "/dev/");
 540         if (!e)
 541                 return -EINVAL;
 542
 543         if (tty_is_vc(name)) {
 544                 _cleanup_close_ int fd = -1;
 545                 unsigned u;
 546                 const char *n;
 547
 548                 n = startswith(e, "tty");
 549                 if (!n)
 550                         return -EINVAL;
 551
 552                 r = safe_atou(n, &u);
 553                 if (r < 0)
 554                         return r;
 555
 556                 if (u <= 0)
 557                         return -EINVAL;
 558
 559                 /* Try to deallocate */
 560                 fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 561                 if (fd < 0)
 562                         return fd;
 563
 564                 r = ioctl(fd, VT_DISALLOCATE, u);
 565                 if (r >= 0)
 566                         return 0;
 567                 if (errno != EBUSY)
 568                         return -errno;
 569         }
 570
 571         /* So this is not a VT (in which case we cannot deallocate it),
 572          * or we failed to deallocate. Let's at least clear the screen. */
 573
 574         _cleanup_close_ int fd2 = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 575         if (fd2 < 0)
 576                 return fd2;
 577
 578         (void) loop_write(fd2,
 579                           "\033[r"   /* clear scrolling region */
 580                           "\033[H"   /* move home */
 581                           "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
 582                           10, false);
 583         return 0;
 584 }
 585
 586 int make_console_stdio(void) {
 587         int fd, r;
 588
 589         /* Make /dev/console the controlling terminal and stdin/stdout/stderr, if we can. If we can't use
 590          * /dev/null instead. This is particularly useful if /dev/console is turned off, e.g. if console=null
 591          * is specified on the kernel command line. */
 592
 593         fd = acquire_terminal("/dev/console", ACQUIRE_TERMINAL_FORCE|ACQUIRE_TERMINAL_PERMISSIVE, USEC_INFINITY);
 594         if (fd < 0) {
 595                 log_warning_errno(fd, "Failed to acquire terminal, using /dev/null stdin/stdout/stderr instead: %m");
 596
 597                 r = make_null_stdio();
 598                 if (r < 0)
 599                         return log_error_errno(r, "Failed to make /dev/null stdin/stdout/stderr: %m");
 600
 601         } else {
 602                 r = reset_terminal_fd(fd, true);
 603                 if (r < 0)
 604                         log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
 605
 606                 r = rearrange_stdio(fd, fd, fd); /* This invalidates 'fd' both on success and on failure. */
 607                 if (r < 0)
 608                         return log_error_errno(r, "Failed to make terminal stdin/stdout/stderr: %m");
 609         }
 610
 611         reset_terminal_feature_caches();
 612         return 0;
 613 }
 614
 615 bool tty_is_vc(const char *tty) {
 616         assert(tty);
 617
 618         return vtnr_from_tty(tty) >= 0;
 619 }
 620
 621 bool tty_is_console(const char *tty) {
 622         assert(tty);
 623
 624         return streq(skip_dev_prefix(tty), "console");
 625 }
 626
 627 int vtnr_from_tty(const char *tty) {
 628         int i, r;
 629
 630         assert(tty);
 631
 632         tty = skip_dev_prefix(tty);
 633
 634         if (!startswith(tty, "tty") )
 635                 return -EINVAL;
 636
 637         if (tty[3] < '0' || tty[3] > '9')
 638                 return -EINVAL;
 639
 640         r = safe_atoi(tty+3, &i);
 641         if (r < 0)
 642                 return r;
 643
 644         if (i < 0 || i > 63)
 645                 return -EINVAL;
 646
 647         return i;
 648 }
 649
 650  int resolve_dev_console(char **ret) {
 651         _cleanup_free_ char *active = NULL;
 652         char *tty;
 653         int r;
 654
 655         assert(ret);
 656
 657         /* Resolve where /dev/console is pointing to, if /sys is actually ours (i.e. not read-only-mounted which is a
 658          * sign for container setups) */
 659
 660         if (path_is_read_only_fs("/sys") > 0)
 661                 return -ENOMEDIUM;
 662
 663         r = read_one_line_file("/sys/class/tty/console/active", &active);
 664         if (r < 0)
 665                 return r;
 666
 667         /* If multiple log outputs are configured the last one is what /dev/console points to */
 668         tty = strrchr(active, ' ');
 669         if (tty)
 670                 tty++;
 671         else
 672                 tty = active;
 673
 674         if (streq(tty, "tty0")) {
 675                 active = mfree(active);
 676
 677                 /* Get the active VC (e.g. tty1) */
 678                 r = read_one_line_file("/sys/class/tty/tty0/active", &active);
 679                 if (r < 0)
 680                         return r;
 681
 682                 tty = active;
 683         }
 684
 685         if (tty == active)
 686                 *ret = TAKE_PTR(active);
 687         else {
 688                 char *tmp;
 689
 690                 tmp = strdup(tty);
 691                 if (!tmp)
 692                         return -ENOMEM;
 693
 694                 *ret = tmp;
 695         }
 696
 697         return 0;
 698 }
 699
 700 int get_kernel_consoles(char ***ret) {
 701         _cleanup_strv_free_ char **l = NULL;
 702         _cleanup_free_ char *line = NULL;
 703         const char *p;
 704         int r;
 705
 706         assert(ret);
 707
 708         /* If /sys is mounted read-only this means we are running in some kind of container environment. In that
 709          * case /sys would reflect the host system, not us, hence ignore the data we can read from it. */
 710         if (path_is_read_only_fs("/sys") > 0)
 711                 goto fallback;
 712
 713         r = read_one_line_file("/sys/class/tty/console/active", &line);
 714         if (r < 0)
 715                 return r;
 716
 717         p = line;
 718         for (;;) {
 719                 _cleanup_free_ char *tty = NULL, *path = NULL;
 720
 721                 r = extract_first_word(&p, &tty, NULL, 0);
 722                 if (r < 0)
 723                         return r;
 724                 if (r == 0)
 725                         break;
 726
 727                 if (streq(tty, "tty0")) {
 728                         tty = mfree(tty);
 729                         r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
 730                         if (r < 0)
 731                                 return r;
 732                 }
 733
 734                 path = path_join("/dev", tty);
 735                 if (!path)
 736                         return -ENOMEM;
 737
 738                 if (access(path, F_OK) < 0) {
 739                         log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
 740                         continue;
 741                 }
 742
 743                 r = strv_consume(&l, TAKE_PTR(path));
 744                 if (r < 0)
 745                         return r;
 746         }
 747
 748         if (strv_isempty(l)) {
 749                 log_debug("No devices found for system console");
 750                 goto fallback;
 751         }
 752
 753         *ret = TAKE_PTR(l);
 754
 755         return 0;
 756
 757 fallback:
 758         r = strv_extend(&l, "/dev/console");
 759         if (r < 0)
 760                 return r;
 761
 762         *ret = TAKE_PTR(l);
 763
 764         return 0;
 765 }
 766
 767 bool tty_is_vc_resolve(const char *tty) {
 768         _cleanup_free_ char *resolved = NULL;
 769
 770         assert(tty);
 771
 772         tty = skip_dev_prefix(tty);
 773
 774         if (streq(tty, "console")) {
 775                 if (resolve_dev_console(&resolved) < 0)
 776                         return false;
 777
 778                 tty = resolved;
 779         }
 780
 781         return tty_is_vc(tty);
 782 }
 783
 784 const char *default_term_for_tty(const char *tty) {
 785         return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220";
 786 }
 787
 788 int fd_columns(int fd) {
 789         struct winsize ws = {};
 790
 791         if (fd < 0)
 792                 return -EBADF;
 793
 794         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 795                 return -errno;
 796
 797         if (ws.ws_col <= 0)
 798                 return -EIO;
 799
 800         return ws.ws_col;
 801 }
 802
 803 unsigned columns(void) {
 804         const char *e;
 805         int c;
 806
 807         if (cached_columns > 0)
 808                 return cached_columns;
 809
 810         c = 0;
 811         e = getenv("COLUMNS");
 812         if (e)
 813                 (void) safe_atoi(e, &c);
 814
 815         if (c <= 0 || c > USHRT_MAX) {
 816                 c = fd_columns(STDOUT_FILENO);
 817                 if (c <= 0)
 818                         c = 80;
 819         }
 820
 821         cached_columns = c;
 822         return cached_columns;
 823 }
 824
 825 int fd_lines(int fd) {
 826         struct winsize ws = {};
 827
 828         if (fd < 0)
 829                 return -EBADF;
 830
 831         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 832                 return -errno;
 833
 834         if (ws.ws_row <= 0)
 835                 return -EIO;
 836
 837         return ws.ws_row;
 838 }
 839
 840 unsigned lines(void) {
 841         const char *e;
 842         int l;
 843
 844         if (cached_lines > 0)
 845                 return cached_lines;
 846
 847         l = 0;
 848         e = getenv("LINES");
 849         if (e)
 850                 (void) safe_atoi(e, &l);
 851
 852         if (l <= 0 || l > USHRT_MAX) {
 853                 l = fd_lines(STDOUT_FILENO);
 854                 if (l <= 0)
 855                         l = 24;
 856         }
 857
 858         cached_lines = l;
 859         return cached_lines;
 860 }
 861
 862 /* intended to be used as a SIGWINCH sighandler */
 863 void columns_lines_cache_reset(int signum) {
 864         cached_columns = 0;
 865         cached_lines = 0;
 866 }
 867
 868 void reset_terminal_feature_caches(void) {
 869         cached_columns = 0;
 870         cached_lines = 0;
 871
 872         cached_color_mode = _COLOR_INVALID;
 873         cached_underline_enabled = -1;
 874         cached_on_tty = -1;
 875 }
 876
 877 bool on_tty(void) {
 878
 879         /* We check both stdout and stderr, so that situations where pipes on the shell are used are reliably
 880          * recognized, regardless if only the output or the errors are piped to some place. Since on_tty() is generally
 881          * used to default to a safer, non-interactive, non-color mode of operation it's probably good to be defensive
 882          * here, and check for both. Note that we don't check for STDIN_FILENO, because it should fine to use fancy
 883          * terminal functionality when outputting stuff, even if the input is piped to us. */
 884
 885         if (cached_on_tty < 0)
 886                 cached_on_tty =
 887                         isatty(STDOUT_FILENO) > 0 &&
 888                         isatty(STDERR_FILENO) > 0;
 889
 890         return cached_on_tty;
 891 }
 892
 893 int getttyname_malloc(int fd, char **ret) {
 894         char path[PATH_MAX], *c; /* PATH_MAX is counted *with* the trailing NUL byte */
 895         int r;
 896
 897         assert(fd >= 0);
 898         assert(ret);
 899
 900         r = ttyname_r(fd, path, sizeof path); /* positive error */
 901         assert(r >= 0);
 902         if (r == ERANGE)
 903                 return -ENAMETOOLONG;
 904         if (r > 0)
 905                 return -r;
 906
 907         c = strdup(skip_dev_prefix(path));
 908         if (!c)
 909                 return -ENOMEM;
 910
 911         *ret = c;
 912         return 0;
 913 }
 914
 915 int getttyname_harder(int fd, char **ret) {
 916         _cleanup_free_ char *s = NULL;
 917         int r;
 918
 919         r = getttyname_malloc(fd, &s);
 920         if (r < 0)
 921                 return r;
 922
 923         if (streq(s, "tty"))
 924                 return get_ctty(0, NULL, ret);
 925
 926         *ret = TAKE_PTR(s);
 927         return 0;
 928 }
 929
 930 int get_ctty_devnr(pid_t pid, dev_t *d) {
 931         int r;
 932         _cleanup_free_ char *line = NULL;
 933         const char *p;
 934         unsigned long ttynr;
 935
 936         assert(pid >= 0);
 937
 938         p = procfs_file_alloca(pid, "stat");
 939         r = read_one_line_file(p, &line);
 940         if (r < 0)
 941                 return r;
 942
 943         p = strrchr(line, ')');
 944         if (!p)
 945                 return -EIO;
 946
 947         p++;
 948
 949         if (sscanf(p, " "
 950                    "%*c "  /* state */
 951                    "%*d "  /* ppid */
 952                    "%*d "  /* pgrp */
 953                    "%*d "  /* session */
 954                    "%lu ", /* ttynr */
 955                    &ttynr) != 1)
 956                 return -EIO;
 957
 958         if (major(ttynr) == 0 && minor(ttynr) == 0)
 959                 return -ENXIO;
 960
 961         if (d)
 962                 *d = (dev_t) ttynr;
 963
 964         return 0;
 965 }
 966
 967 int get_ctty(pid_t pid, dev_t *ret_devnr, char **ret) {
 968         _cleanup_free_ char *fn = NULL, *b = NULL;
 969         dev_t devnr;
 970         int r;
 971
 972         r = get_ctty_devnr(pid, &devnr);
 973         if (r < 0)
 974                 return r;
 975
 976         r = device_path_make_canonical(S_IFCHR, devnr, &fn);
 977         if (r < 0) {
 978                 if (r != -ENOENT) /* No symlink for this in /dev/char/? */
 979                         return r;
 980
 981                 if (major(devnr) == 136) {
 982                         /* This is an ugly hack: PTY devices are not listed in /dev/char/, as they don't follow the
 983                          * Linux device model. This means we have no nice way to match them up against their actual
 984                          * device node. Let's hence do the check by the fixed, assigned major number. Normally we try
 985                          * to avoid such fixed major/minor matches, but there appears to nother nice way to handle
 986                          * this. */
 987
 988                         if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
 989                                 return -ENOMEM;
 990                 } else {
 991                         /* Probably something similar to the ptys which have no symlink in /dev/char/. Let's return
 992                          * something vaguely useful. */
 993
 994                         r = device_path_make_major_minor(S_IFCHR, devnr, &fn);
 995                         if (r < 0)
 996                                 return r;
 997                 }
 998         }
 999
1000         if (!b) {
1001                 const char *w;
1002
1003                 w = path_startswith(fn, "/dev/");
1004                 if (w) {
1005                         b = strdup(w);
1006                         if (!b)
1007                                 return -ENOMEM;
1008                 } else
1009                         b = TAKE_PTR(fn);
1010         }
1011
1012         if (ret)
1013                 *ret = TAKE_PTR(b);
1014
1015         if (ret_devnr)
1016                 *ret_devnr = devnr;
1017
1018         return 0;
1019 }
1020
1021 int ptsname_malloc(int fd, char **ret) {
1022         size_t l = 100;
1023
1024         assert(fd >= 0);
1025         assert(ret);
1026
1027         for (;;) {
1028                 char *c;
1029
1030                 c = new(char, l);
1031                 if (!c)
1032                         return -ENOMEM;
1033
1034                 if (ptsname_r(fd, c, l) == 0) {
1035                         *ret = c;
1036                         return 0;
1037                 }
1038                 if (errno != ERANGE) {
1039                         free(c);
1040                         return -errno;
1041                 }
1042
1043                 free(c);
1044
1045                 if (l > SIZE_MAX / 2)
1046                         return -ENOMEM;
1047
1048                 l *= 2;
1049         }
1050 }
1051
1052 int openpt_allocate(int flags, char **ret_slave) {
1053         _cleanup_close_ int fd = -1;
1054         _cleanup_free_ char *p = NULL;
1055         int r;
1056
1057         fd = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1058         if (fd < 0)
1059                 return -errno;
1060
1061         if (ret_slave) {
1062                 r = ptsname_malloc(fd, &p);
1063                 if (r < 0)
1064                         return r;
1065
1066                 if (!path_startswith(p, "/dev/pts/"))
1067                         return -EINVAL;
1068         }
1069
1070         if (unlockpt(fd) < 0)
1071                 return -errno;
1072
1073         if (ret_slave)
1074                 *ret_slave = TAKE_PTR(p);
1075
1076         return TAKE_FD(fd);
1077 }
1078
1079 static int ptsname_namespace(int pty, char **ret) {
1080         int no = -1, r;
1081
1082         /* Like ptsname(), but doesn't assume that the path is
1083          * accessible in the local namespace. */
1084
1085         r = ioctl(pty, TIOCGPTN, &no);
1086         if (r < 0)
1087                 return -errno;
1088
1089         if (no < 0)
1090                 return -EIO;
1091
1092         if (asprintf(ret, "/dev/pts/%i", no) < 0)
1093                 return -ENOMEM;
1094
1095         return 0;
1096 }
1097
1098 int openpt_allocate_in_namespace(pid_t pid, int flags, char **ret_slave) {
1099         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1, fd = -1;
1100         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1101         pid_t child;
1102         int r;
1103
1104         assert(pid > 0);
1105
1106         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1107         if (r < 0)
1108                 return r;
1109
1110         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1111                 return -errno;
1112
1113         r = namespace_fork("(sd-openptns)", "(sd-openpt)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG,
1114                            pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child);
1115         if (r < 0)
1116                 return r;
1117         if (r == 0) {
1118                 pair[0] = safe_close(pair[0]);
1119
1120                 fd = openpt_allocate(flags, NULL);
1121                 if (fd < 0)
1122                         _exit(EXIT_FAILURE);
1123
1124                 if (send_one_fd(pair[1], fd, 0) < 0)
1125                         _exit(EXIT_FAILURE);
1126
1127                 _exit(EXIT_SUCCESS);
1128         }
1129
1130         pair[1] = safe_close(pair[1]);
1131
1132         r = wait_for_terminate_and_check("(sd-openptns)", child, 0);
1133         if (r < 0)
1134                 return r;
1135         if (r != EXIT_SUCCESS)
1136                 return -EIO;
1137
1138         fd = receive_one_fd(pair[0], 0);
1139         if (fd < 0)
1140                 return fd;
1141
1142         if (ret_slave) {
1143                 r = ptsname_namespace(fd, ret_slave);
1144                 if (r < 0)
1145                         return r;
1146         }
1147
1148         return TAKE_FD(fd);
1149 }
1150
1151 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1152         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1153         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1154         pid_t child;
1155         int r;
1156
1157         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1158         if (r < 0)
1159                 return r;
1160
1161         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1162                 return -errno;
1163
1164         r = namespace_fork("(sd-terminalns)", "(sd-terminal)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG,
1165                            pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child);
1166         if (r < 0)
1167                 return r;
1168         if (r == 0) {
1169                 int master;
1170
1171                 pair[0] = safe_close(pair[0]);
1172
1173                 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1174                 if (master < 0)
1175                         _exit(EXIT_FAILURE);
1176
1177                 if (send_one_fd(pair[1], master, 0) < 0)
1178                         _exit(EXIT_FAILURE);
1179
1180                 _exit(EXIT_SUCCESS);
1181         }
1182
1183         pair[1] = safe_close(pair[1]);
1184
1185         r = wait_for_terminate_and_check("(sd-terminalns)", child, 0);
1186         if (r < 0)
1187                 return r;
1188         if (r != EXIT_SUCCESS)
1189                 return -EIO;
1190
1191         return receive_one_fd(pair[0], 0);
1192 }
1193
1194 static bool getenv_terminal_is_dumb(void) {
1195         const char *e;
1196
1197         e = getenv("TERM");
1198         if (!e)
1199                 return true;
1200
1201         return streq(e, "dumb");
1202 }
1203
1204 bool terminal_is_dumb(void) {
1205         if (!on_tty())
1206                 return true;
1207
1208         return getenv_terminal_is_dumb();
1209 }
1210
1211 static ColorMode parse_systemd_colors(void) {
1212         const char *e;
1213         int r;
1214
1215         e = getenv("SYSTEMD_COLORS");
1216         if (!e)
1217                 return _COLOR_INVALID;
1218         if (streq(e, "16"))
1219                 return COLOR_16;
1220         if (streq(e, "256"))
1221                 return COLOR_256;
1222         r = parse_boolean(e);
1223         if (r >= 0)
1224                 return r > 0 ? COLOR_ON : COLOR_OFF;
1225         return _COLOR_INVALID;
1226 }
1227
1228 ColorMode get_color_mode(void) {
1229
1230         /* Returns the mode used to choose output colors. The possible modes are COLOR_OFF for no colors,
1231          * COLOR_16 for only the base 16 ANSI colors, COLOR_256 for more colors and COLOR_ON for unrestricted
1232          * color output. For that we check $SYSTEMD_COLORS first (which is the explicit way to
1233          * change the mode). If that didn't work we turn colors off unless we are on a TTY. And if we are on a TTY
1234          * we turn it off if $TERM is set to "dumb". There's one special tweak though: if we are PID 1 then we do not
1235          * check whether we are connected to a TTY, because we don't keep /dev/console open continuously due to fear
1236          * of SAK, and hence things are a bit weird. */
1237         ColorMode m;
1238
1239         if (cached_color_mode < 0) {
1240                 m = parse_systemd_colors();
1241                 if (m >= 0)
1242                         cached_color_mode = m;
1243                 else if (getenv("NO_COLOR"))
1244                         /* We only check for the presence of the variable; value is ignored. */
1245                         cached_color_mode = COLOR_OFF;
1246
1247                 else if (getpid_cached() == 1)
1248                         /* PID1 outputs to the console without holding it open all the time.
1249                          *
1250                          * Note that the Linux console can only display 16 colors. We still enable 256 color
1251                          * mode even for PID1 output though (which typically goes to the Linux console),
1252                          * since the Linux console is able to parse the 256 color sequences and automatically
1253                          * map them to the closest color in the 16 color palette (since kernel 3.16). Doing
1254                          * 256 colors is nice for people who invoke systemd in a container or via a serial
1255                          * link or such, and use a true 256 color terminal to do so. */
1256                         cached_color_mode = getenv_terminal_is_dumb() ? COLOR_OFF : COLOR_256;
1257                 else
1258                         cached_color_mode = terminal_is_dumb() ? COLOR_OFF : COLOR_256;
1259         }
1260
1261         return cached_color_mode;
1262 }
1263
1264 bool dev_console_colors_enabled(void) {
1265         _cleanup_free_ char *s = NULL;
1266         ColorMode m;
1267
1268         /* Returns true if we assume that color is supported on /dev/console.
1269          *
1270          * For that we first check if we explicitly got told to use colors or not, by checking $SYSTEMD_COLORS. If that
1271          * isn't set we check whether PID 1 has $TERM set, and if not, whether TERM is set on the kernel command
1272          * line. If we find $TERM set we assume color if it's not set to "dumb", similarly to how regular
1273          * colors_enabled() operates. */
1274
1275         m = parse_systemd_colors();
1276         if (m >= 0)
1277                 return m;
1278
1279         if (getenv("NO_COLOR"))
1280                 return false;
1281
1282         if (getenv_for_pid(1, "TERM", &s) <= 0)
1283                 (void) proc_cmdline_get_key("TERM", 0, &s);
1284
1285         return !streq_ptr(s, "dumb");
1286 }
1287
1288 bool underline_enabled(void) {
1289
1290         if (cached_underline_enabled < 0) {
1291
1292                 /* The Linux console doesn't support underlining, turn it off, but only there. */
1293
1294                 if (colors_enabled())
1295                         cached_underline_enabled = !streq_ptr(getenv("TERM"), "linux");
1296                 else
1297                         cached_underline_enabled = false;
1298         }
1299
1300         return cached_underline_enabled;
1301 }
1302
1303 int vt_default_utf8(void) {
1304         _cleanup_free_ char *b = NULL;
1305         int r;
1306
1307         /* Read the default VT UTF8 setting from the kernel */
1308
1309         r = read_one_line_file("/sys/module/vt/parameters/default_utf8", &b);
1310         if (r < 0)
1311                 return r;
1312
1313         return parse_boolean(b);
1314 }
1315
1316 int vt_reset_keyboard(int fd) {
1317         int kb;
1318
1319         /* If we can't read the default, then default to unicode. It's 2017 after all. */
1320         kb = vt_default_utf8() != 0 ? K_UNICODE : K_XLATE;
1321
1322         if (ioctl(fd, KDSKBMODE, kb) < 0)
1323                 return -errno;
1324
1325         return 0;
1326 }
1327
1328 int vt_restore(int fd) {
1329         static const struct vt_mode mode = {
1330                 .mode = VT_AUTO,
1331         };
1332         int r, q = 0;
1333
1334         if (isatty(fd) < 1)
1335                 return log_debug_errno(errno, "Asked to restore the VT for an fd that does not refer to a terminal: %m");
1336
1337         if (ioctl(fd, KDSETMODE, KD_TEXT) < 0)
1338                 q = log_debug_errno(errno, "Failed to set VT in text mode, ignoring: %m");
1339
1340         r = vt_reset_keyboard(fd);
1341         if (r < 0) {
1342                 log_debug_errno(r, "Failed to reset keyboard mode, ignoring: %m");
1343                 if (q >= 0)
1344                         q = r;
1345         }
1346
1347         if (ioctl(fd, VT_SETMODE, &mode) < 0) {
1348                 log_debug_errno(errno, "Failed to set VT_AUTO mode, ignoring: %m");
1349                 if (q >= 0)
1350                         q = -errno;
1351         }
1352
1353         r = fchmod_and_chown(fd, TTY_MODE, 0, GID_INVALID);
1354         if (r < 0) {
1355                 log_debug_errno(r, "Failed to chmod()/chown() VT, ignoring: %m");
1356                 if (q >= 0)
1357                         q = r;
1358         }
1359
1360         return q;
1361 }
1362
1363 int vt_release(int fd, bool restore) {
1364         assert(fd >= 0);
1365
1366         /* This function releases the VT by acknowledging the VT-switch signal
1367          * sent by the kernel and optionally reset the VT in text and auto
1368          * VT-switching modes. */
1369
1370         if (isatty(fd) < 1)
1371                 return log_debug_errno(errno, "Asked to release the VT for an fd that does not refer to a terminal: %m");
1372
1373         if (ioctl(fd, VT_RELDISP, 1) < 0)
1374                 return -errno;
1375
1376         if (restore)
1377                 return vt_restore(fd);
1378
1379         return 0;
1380 }
1381
1382 void get_log_colors(int priority, const char **on, const char **off, const char **highlight) {
1383         /* Note that this will initialize output variables only when there's something to output.
1384          * The caller must pre-initialize to "" or NULL as appropriate. */
1385
1386         if (priority <= LOG_ERR) {
1387                 if (on)
1388                         *on = ansi_highlight_red();
1389                 if (off)
1390                         *off = ansi_normal();
1391                 if (highlight)
1392                         *highlight = ansi_highlight();
1393
1394         } else if (priority <= LOG_WARNING) {
1395                 if (on)
1396                         *on = ansi_highlight_yellow();
1397                 if (off)
1398                         *off = ansi_normal();
1399                 if (highlight)
1400                         *highlight = ansi_highlight();
1401
1402         } else if (priority <= LOG_NOTICE) {
1403                 if (on)
1404                         *on = ansi_highlight();
1405                 if (off)
1406                         *off = ansi_normal();
1407                 if (highlight)
1408                         *highlight = ansi_highlight_red();
1409
1410         } else if (priority >= LOG_DEBUG) {
1411                 if (on)
1412                         *on = ansi_grey();
1413                 if (off)
1414                         *off = ansi_normal();
1415                 if (highlight)
1416                         *highlight = ansi_highlight_red();
1417         }
1418 }