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 "constants.h"
  25 #include "devnum-util.h"
  26 #include "env-util.h"
  27 #include "fd-util.h"
  28 #include "fileio.h"
  29 #include "fs-util.h"
  30 #include "hexdecoct.h"
  31 #include "inotify-util.h"
  32 #include "io-util.h"
  33 #include "log.h"
  34 #include "macro.h"
  35 #include "namespace-util.h"
  36 #include "parse-util.h"
  37 #include "path-util.h"
  38 #include "proc-cmdline.h"
  39 #include "process-util.h"
  40 #include "socket-util.h"
  41 #include "stat-util.h"
  42 #include "stdio-util.h"
  43 #include "string-util.h"
  44 #include "strv.h"
  45 #include "terminal-util.h"
  46 #include "time-util.h"
  47 #include "user-util.h"
  48
  49 static volatile unsigned cached_columns = 0;
  50 static volatile unsigned cached_lines = 0;
  51
  52 static volatile int cached_on_tty = -1;
  53 static volatile int cached_on_dev_null = -1;
  54 static volatile int cached_color_mode = _COLOR_INVALID;
  55 static volatile int cached_underline_enabled = -1;
  56
  57 bool isatty_safe(int fd) {
  58         assert(fd >= 0);
  59
  60         if (isatty(fd))
  61                 return true;
  62
  63         /* Be resilient if we're working on stdio, since they're set up by parent process. */
  64         assert(errno != EBADF || IN_SET(fd, STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO));
  65
  66         return false;
  67 }
  68
  69 int chvt(int vt) {
  70         _cleanup_close_ int fd = -EBADF;
  71
  72         /* Switch to the specified vt number. If the VT is specified <= 0 switch to the VT the kernel log messages go,
  73          * if that's configured. */
  74
  75         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
  76         if (fd < 0)
  77                 return -errno;
  78
  79         if (vt <= 0) {
  80                 int tiocl[2] = {
  81                         TIOCL_GETKMSGREDIRECT,
  82                         0
  83                 };
  84
  85                 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
  86                         return -errno;
  87
  88                 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
  89         }
  90
  91         return RET_NERRNO(ioctl(fd, VT_ACTIVATE, vt));
  92 }
  93
  94 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
  95         _cleanup_free_ char *line = NULL;
  96         struct termios old_termios;
  97         int r, fd;
  98
  99         assert(f);
 100         assert(ret);
 101
 102         /* If this is a terminal, then switch canonical mode off, so that we can read a single
 103          * character. (Note that fmemopen() streams do not have an fd associated with them, let's handle that
 104          * nicely.) */
 105         fd = fileno(f);
 106         if (fd >= 0 && tcgetattr(fd, &old_termios) >= 0) {
 107                 struct termios new_termios = old_termios;
 108
 109                 new_termios.c_lflag &= ~ICANON;
 110                 new_termios.c_cc[VMIN] = 1;
 111                 new_termios.c_cc[VTIME] = 0;
 112
 113                 if (tcsetattr(fd, TCSADRAIN, &new_termios) >= 0) {
 114                         char c;
 115
 116                         if (t != USEC_INFINITY) {
 117                                 if (fd_wait_for_event(fd, POLLIN, t) <= 0) {
 118                                         (void) tcsetattr(fd, TCSADRAIN, &old_termios);
 119                                         return -ETIMEDOUT;
 120                                 }
 121                         }
 122
 123                         r = safe_fgetc(f, &c);
 124                         (void) tcsetattr(fd, TCSADRAIN, &old_termios);
 125                         if (r < 0)
 126                                 return r;
 127                         if (r == 0)
 128                                 return -EIO;
 129
 130                         if (need_nl)
 131                                 *need_nl = c != '\n';
 132
 133                         *ret = c;
 134                         return 0;
 135                 }
 136         }
 137
 138         if (t != USEC_INFINITY && fd > 0) {
 139                 /* Let's wait the specified amount of time for input. When we have no fd we skip this, under
 140                  * the assumption that this is an fmemopen() stream or so where waiting doesn't make sense
 141                  * anyway, as the data is either already in the stream or cannot possible be placed there
 142                  * while we access the stream */
 143
 144                 if (fd_wait_for_event(fd, POLLIN, t) <= 0)
 145                         return -ETIMEDOUT;
 146         }
 147
 148         /* If this is not a terminal, then read a full line instead */
 149
 150         r = read_line(f, 16, &line); /* longer than necessary, to eat up UTF-8 chars/vt100 key sequences */
 151         if (r < 0)
 152                 return r;
 153         if (r == 0)
 154                 return -EIO;
 155
 156         if (strlen(line) != 1)
 157                 return -EBADMSG;
 158
 159         if (need_nl)
 160                 *need_nl = false;
 161
 162         *ret = line[0];
 163         return 0;
 164 }
 165
 166 #define DEFAULT_ASK_REFRESH_USEC (2*USEC_PER_SEC)
 167
 168 int ask_char(char *ret, const char *replies, const char *fmt, ...) {
 169         int r;
 170
 171         assert(ret);
 172         assert(replies);
 173         assert(fmt);
 174
 175         for (;;) {
 176                 va_list ap;
 177                 char c;
 178                 bool need_nl = true;
 179
 180                 fputs(ansi_highlight(), stdout);
 181
 182                 putchar('\r');
 183
 184                 va_start(ap, fmt);
 185                 vprintf(fmt, ap);
 186                 va_end(ap);
 187
 188                 fputs(ansi_normal(), stdout);
 189
 190                 fflush(stdout);
 191
 192                 r = read_one_char(stdin, &c, DEFAULT_ASK_REFRESH_USEC, &need_nl);
 193                 if (r < 0) {
 194
 195                         if (r == -ETIMEDOUT)
 196                                 continue;
 197
 198                         if (r == -EBADMSG) {
 199                                 puts("Bad input, please try again.");
 200                                 continue;
 201                         }
 202
 203                         putchar('\n');
 204                         return r;
 205                 }
 206
 207                 if (need_nl)
 208                         putchar('\n');
 209
 210                 if (strchr(replies, c)) {
 211                         *ret = c;
 212                         return 0;
 213                 }
 214
 215                 puts("Read unexpected character, please try again.");
 216         }
 217 }
 218
 219 int ask_string(char **ret, const char *text, ...) {
 220         _cleanup_free_ char *line = NULL;
 221         va_list ap;
 222         int r;
 223
 224         assert(ret);
 225         assert(text);
 226
 227         fputs(ansi_highlight(), stdout);
 228
 229         va_start(ap, text);
 230         vprintf(text, ap);
 231         va_end(ap);
 232
 233         fputs(ansi_normal(), stdout);
 234
 235         fflush(stdout);
 236
 237         r = read_line(stdin, LONG_LINE_MAX, &line);
 238         if (r < 0)
 239                 return r;
 240         if (r == 0)
 241                 return -EIO;
 242
 243         *ret = TAKE_PTR(line);
 244         return 0;
 245 }
 246
 247 int reset_terminal_fd(int fd, bool switch_to_text) {
 248         struct termios termios;
 249         int r;
 250
 251         /* Set terminal to some sane defaults */
 252
 253         assert(fd >= 0);
 254
 255         if (!isatty_safe(fd))
 256                 return log_debug_errno(errno, "Asked to reset a terminal that actually isn't a terminal: %m");
 257
 258         /* We leave locked terminal attributes untouched, so that Plymouth may set whatever it wants to set,
 259          * and we don't interfere with that. */
 260
 261         /* Disable exclusive mode, just in case */
 262         if (ioctl(fd, TIOCNXCL) < 0)
 263                 log_debug_errno(errno, "TIOCNXCL ioctl failed on TTY, ignoring: %m");
 264
 265         /* Switch to text mode */
 266         if (switch_to_text)
 267                 if (ioctl(fd, KDSETMODE, KD_TEXT) < 0)
 268                         log_debug_errno(errno, "KDSETMODE ioctl for switching to text mode failed on TTY, ignoring: %m");
 269
 270
 271         /* Set default keyboard mode */
 272         r = vt_reset_keyboard(fd);
 273         if (r < 0)
 274                 log_debug_errno(r, "Failed to reset VT keyboard, ignoring: %m");
 275
 276         if (tcgetattr(fd, &termios) < 0) {
 277                 r = log_debug_errno(errno, "Failed to get terminal parameters: %m");
 278                 goto finish;
 279         }
 280
 281         /* We only reset the stuff that matters to the software. How
 282          * hardware is set up we don't touch assuming that somebody
 283          * else will do that for us */
 284
 285         termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
 286         termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
 287         termios.c_oflag |= ONLCR | OPOST;
 288         termios.c_cflag |= CREAD;
 289         termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE;
 290
 291         termios.c_cc[VINTR]    =   03;  /* ^C */
 292         termios.c_cc[VQUIT]    =  034;  /* ^\ */
 293         termios.c_cc[VERASE]   = 0177;
 294         termios.c_cc[VKILL]    =  025;  /* ^X */
 295         termios.c_cc[VEOF]     =   04;  /* ^D */
 296         termios.c_cc[VSTART]   =  021;  /* ^Q */
 297         termios.c_cc[VSTOP]    =  023;  /* ^S */
 298         termios.c_cc[VSUSP]    =  032;  /* ^Z */
 299         termios.c_cc[VLNEXT]   =  026;  /* ^V */
 300         termios.c_cc[VWERASE]  =  027;  /* ^W */
 301         termios.c_cc[VREPRINT] =  022;  /* ^R */
 302         termios.c_cc[VEOL]     =    0;
 303         termios.c_cc[VEOL2]    =    0;
 304
 305         termios.c_cc[VTIME]  = 0;
 306         termios.c_cc[VMIN]   = 1;
 307
 308         r = RET_NERRNO(tcsetattr(fd, TCSANOW, &termios));
 309         if (r < 0) {
 310                 log_debug_errno(r, "Failed to set terminal parameters: %m");
 311                 goto finish;
 312         }
 313
 314         if (!terminal_is_dumb()) {
 315                 r = fd_nonblock(fd, true);
 316                 if (r < 0) {
 317                         log_debug_errno(r, "Failed to set terminal to non-blocking mode: %m");
 318                         goto finish;
 319                 }
 320
 321                  /* Enable line wrapping. */
 322                 (void) loop_write_full(fd, "\033[?7h", SIZE_MAX, 50 * USEC_PER_MSEC);
 323
 324                 if (r > 0) {
 325                         r = fd_nonblock(fd, false);
 326                         if (r < 0) {
 327                                 log_debug_errno(r, "Failed to set terminal back to blocking mode: %m");
 328                                 goto finish;
 329                         }
 330                 }
 331         }
 332 finish:
 333         /* Just in case, flush all crap out */
 334         (void) tcflush(fd, TCIOFLUSH);
 335
 336         return r;
 337 }
 338
 339 int reset_terminal(const char *name) {
 340         _cleanup_close_ int fd = -EBADF;
 341
 342         /* We open the terminal with O_NONBLOCK here, to ensure we
 343          * don't block on carrier if this is a terminal with carrier
 344          * configured. */
 345
 346         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 347         if (fd < 0)
 348                 return fd;
 349
 350         return reset_terminal_fd(fd, true);
 351 }
 352
 353 int open_terminal(const char *name, int mode) {
 354         _cleanup_close_ int fd = -EBADF;
 355         unsigned c = 0;
 356
 357         /*
 358          * If a TTY is in the process of being closed opening it might cause EIO. This is horribly awful, but
 359          * unlikely to be changed in the kernel. Hence we work around this problem by retrying a couple of
 360          * times.
 361          *
 362          * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
 363          */
 364
 365         if (mode & O_CREAT)
 366                 return -EINVAL;
 367
 368         for (;;) {
 369                 fd = open(name, mode, 0);
 370                 if (fd >= 0)
 371                         break;
 372
 373                 if (errno != EIO)
 374                         return -errno;
 375
 376                 /* Max 1s in total */
 377                 if (c >= 20)
 378                         return -errno;
 379
 380                 (void) usleep_safe(50 * USEC_PER_MSEC);
 381                 c++;
 382         }
 383
 384         if (!isatty_safe(fd))
 385                 return negative_errno();
 386
 387         return TAKE_FD(fd);
 388 }
 389
 390 int acquire_terminal(
 391                 const char *name,
 392                 AcquireTerminalFlags flags,
 393                 usec_t timeout) {
 394
 395         _cleanup_close_ int notify = -EBADF, fd = -EBADF;
 396         usec_t ts = USEC_INFINITY;
 397         int r, wd = -1;
 398
 399         assert(name);
 400         assert(IN_SET(flags & ~ACQUIRE_TERMINAL_PERMISSIVE, ACQUIRE_TERMINAL_TRY, ACQUIRE_TERMINAL_FORCE, ACQUIRE_TERMINAL_WAIT));
 401
 402         /* We use inotify to be notified when the tty is closed. We create the watch before checking if we can actually
 403          * acquire it, so that we don't lose any event.
 404          *
 405          * Note: strictly speaking this actually watches for the device being closed, it does *not* really watch
 406          * whether a tty loses its controlling process. However, unless some rogue process uses TIOCNOTTY on /dev/tty
 407          * *after* closing its tty otherwise this will not become a problem. As long as the administrator makes sure to
 408          * not configure any service on the same tty as an untrusted user this should not be a problem. (Which they
 409          * probably should not do anyway.) */
 410
 411         if ((flags & ~ACQUIRE_TERMINAL_PERMISSIVE) == ACQUIRE_TERMINAL_WAIT) {
 412                 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
 413                 if (notify < 0)
 414                         return -errno;
 415
 416                 wd = inotify_add_watch(notify, name, IN_CLOSE);
 417                 if (wd < 0)
 418                         return -errno;
 419
 420                 if (timeout != USEC_INFINITY)
 421                         ts = now(CLOCK_MONOTONIC);
 422         }
 423
 424         for (;;) {
 425                 struct sigaction sa_old, sa_new = {
 426                         .sa_handler = SIG_IGN,
 427                         .sa_flags = SA_RESTART,
 428                 };
 429
 430                 if (notify >= 0) {
 431                         r = flush_fd(notify);
 432                         if (r < 0)
 433                                 return r;
 434                 }
 435
 436                 /* We pass here O_NOCTTY only so that we can check the return value TIOCSCTTY and have a reliable way
 437                  * to figure out if we successfully became the controlling process of the tty */
 438                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 439                 if (fd < 0)
 440                         return fd;
 441
 442                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed if we already own the tty. */
 443                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 444
 445                 /* First, try to get the tty */
 446                 r = RET_NERRNO(ioctl(fd, TIOCSCTTY, (flags & ~ACQUIRE_TERMINAL_PERMISSIVE) == ACQUIRE_TERMINAL_FORCE));
 447
 448                 /* Reset signal handler to old value */
 449                 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 450
 451                 /* Success? Exit the loop now! */
 452                 if (r >= 0)
 453                         break;
 454
 455                 /* Any failure besides -EPERM? Fail, regardless of the mode. */
 456                 if (r != -EPERM)
 457                         return r;
 458
 459                 if (flags & ACQUIRE_TERMINAL_PERMISSIVE) /* If we are in permissive mode, then EPERM is fine, turn this
 460                                                           * into a success. Note that EPERM is also returned if we
 461                                                           * already are the owner of the TTY. */
 462                         break;
 463
 464                 if (flags != ACQUIRE_TERMINAL_WAIT) /* If we are in TRY or FORCE mode, then propagate EPERM as EPERM */
 465                         return r;
 466
 467                 assert(notify >= 0);
 468                 assert(wd >= 0);
 469
 470                 for (;;) {
 471                         union inotify_event_buffer buffer;
 472                         ssize_t l;
 473
 474                         if (timeout != USEC_INFINITY) {
 475                                 usec_t n;
 476
 477                                 assert(ts != USEC_INFINITY);
 478
 479                                 n = usec_sub_unsigned(now(CLOCK_MONOTONIC), ts);
 480                                 if (n >= timeout)
 481                                         return -ETIMEDOUT;
 482
 483                                 r = fd_wait_for_event(notify, POLLIN, usec_sub_unsigned(timeout, n));
 484                                 if (r < 0)
 485                                         return r;
 486                                 if (r == 0)
 487                                         return -ETIMEDOUT;
 488                         }
 489
 490                         l = read(notify, &buffer, sizeof(buffer));
 491                         if (l < 0) {
 492                                 if (ERRNO_IS_TRANSIENT(errno))
 493                                         continue;
 494
 495                                 return -errno;
 496                         }
 497
 498                         FOREACH_INOTIFY_EVENT(e, buffer, l) {
 499                                 if (e->mask & IN_Q_OVERFLOW) /* If we hit an inotify queue overflow, simply check if the terminal is up for grabs now. */
 500                                         break;
 501
 502                                 if (e->wd != wd || !(e->mask & IN_CLOSE)) /* Safety checks */
 503                                         return -EIO;
 504                         }
 505
 506                         break;
 507                 }
 508
 509                 /* We close the tty fd here since if the old session ended our handle will be dead. It's important that
 510                  * we do this after sleeping, so that we don't enter an endless loop. */
 511                 fd = safe_close(fd);
 512         }
 513
 514         return TAKE_FD(fd);
 515 }
 516
 517 int release_terminal(void) {
 518         static const struct sigaction sa_new = {
 519                 .sa_handler = SIG_IGN,
 520                 .sa_flags = SA_RESTART,
 521         };
 522
 523         _cleanup_close_ int fd = -EBADF;
 524         struct sigaction sa_old;
 525         int r;
 526
 527         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 528         if (fd < 0)
 529                 return -errno;
 530
 531         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 532          * by our own TIOCNOTTY */
 533         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 534
 535         r = RET_NERRNO(ioctl(fd, TIOCNOTTY));
 536
 537         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 538
 539         return r;
 540 }
 541
 542 int terminal_vhangup_fd(int fd) {
 543         assert(fd >= 0);
 544         return RET_NERRNO(ioctl(fd, TIOCVHANGUP));
 545 }
 546
 547 int terminal_vhangup(const char *name) {
 548         _cleanup_close_ int fd = -EBADF;
 549
 550         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 551         if (fd < 0)
 552                 return fd;
 553
 554         return terminal_vhangup_fd(fd);
 555 }
 556
 557 int vt_disallocate(const char *name) {
 558         const char *e;
 559         int r;
 560
 561         /* Deallocate the VT if possible. If not possible
 562          * (i.e. because it is the active one), at least clear it
 563          * entirely (including the scrollback buffer). */
 564
 565         e = path_startswith(name, "/dev/");
 566         if (!e)
 567                 return -EINVAL;
 568
 569         if (tty_is_vc(name)) {
 570                 _cleanup_close_ int fd = -EBADF;
 571                 unsigned u;
 572                 const char *n;
 573
 574                 n = startswith(e, "tty");
 575                 if (!n)
 576                         return -EINVAL;
 577
 578                 r = safe_atou(n, &u);
 579                 if (r < 0)
 580                         return r;
 581
 582                 if (u <= 0)
 583                         return -EINVAL;
 584
 585                 /* Try to deallocate */
 586                 fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 587                 if (fd < 0)
 588                         return fd;
 589
 590                 r = ioctl(fd, VT_DISALLOCATE, u);
 591                 if (r >= 0)
 592                         return 0;
 593                 if (errno != EBUSY)
 594                         return -errno;
 595         }
 596
 597         /* So this is not a VT (in which case we cannot deallocate it),
 598          * or we failed to deallocate. Let's at least clear the screen. */
 599
 600         _cleanup_close_ int fd2 = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 601         if (fd2 < 0)
 602                 return fd2;
 603
 604         (void) loop_write(fd2,
 605                           "\033[r"   /* clear scrolling region */
 606                           "\033[H"   /* move home */
 607                           "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
 608                           10);
 609         return 0;
 610 }
 611
 612 int make_console_stdio(void) {
 613         int fd, r;
 614
 615         /* Make /dev/console the controlling terminal and stdin/stdout/stderr, if we can. If we can't use
 616          * /dev/null instead. This is particularly useful if /dev/console is turned off, e.g. if console=null
 617          * is specified on the kernel command line. */
 618
 619         fd = acquire_terminal("/dev/console", ACQUIRE_TERMINAL_FORCE|ACQUIRE_TERMINAL_PERMISSIVE, USEC_INFINITY);
 620         if (fd < 0) {
 621                 log_warning_errno(fd, "Failed to acquire terminal, using /dev/null stdin/stdout/stderr instead: %m");
 622
 623                 r = make_null_stdio();
 624                 if (r < 0)
 625                         return log_error_errno(r, "Failed to make /dev/null stdin/stdout/stderr: %m");
 626
 627         } else {
 628                 unsigned rows, cols;
 629
 630                 r = reset_terminal_fd(fd, /* switch_to_text= */ true);
 631                 if (r < 0)
 632                         log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
 633
 634                 r = proc_cmdline_tty_size("/dev/console", &rows, &cols);
 635                 if (r < 0)
 636                         log_warning_errno(r, "Failed to get terminal size, ignoring: %m");
 637                 else {
 638                         r = terminal_set_size_fd(fd, NULL, rows, cols);
 639                         if (r < 0)
 640                                 log_warning_errno(r, "Failed to set terminal size, ignoring: %m");
 641                 }
 642
 643                 r = rearrange_stdio(fd, fd, fd); /* This invalidates 'fd' both on success and on failure. */
 644                 if (r < 0)
 645                         return log_error_errno(r, "Failed to make terminal stdin/stdout/stderr: %m");
 646         }
 647
 648         reset_terminal_feature_caches();
 649         return 0;
 650 }
 651
 652 bool tty_is_vc(const char *tty) {
 653         assert(tty);
 654
 655         return vtnr_from_tty(tty) >= 0;
 656 }
 657
 658 bool tty_is_console(const char *tty) {
 659         assert(tty);
 660
 661         return streq(skip_dev_prefix(tty), "console");
 662 }
 663
 664 int vtnr_from_tty(const char *tty) {
 665         int i, r;
 666
 667         assert(tty);
 668
 669         tty = skip_dev_prefix(tty);
 670
 671         if (!startswith(tty, "tty") )
 672                 return -EINVAL;
 673
 674         if (!ascii_isdigit(tty[3]))
 675                 return -EINVAL;
 676
 677         r = safe_atoi(tty+3, &i);
 678         if (r < 0)
 679                 return r;
 680
 681         if (i < 0 || i > 63)
 682                 return -EINVAL;
 683
 684         return i;
 685 }
 686
 687  int resolve_dev_console(char **ret) {
 688         _cleanup_free_ char *active = NULL;
 689         char *tty;
 690         int r;
 691
 692         assert(ret);
 693
 694         /* Resolve where /dev/console is pointing to, if /sys is actually ours (i.e. not read-only-mounted which is a
 695          * sign for container setups) */
 696
 697         if (path_is_read_only_fs("/sys") > 0)
 698                 return -ENOMEDIUM;
 699
 700         r = read_one_line_file("/sys/class/tty/console/active", &active);
 701         if (r < 0)
 702                 return r;
 703
 704         /* If multiple log outputs are configured the last one is what /dev/console points to */
 705         tty = strrchr(active, ' ');
 706         if (tty)
 707                 tty++;
 708         else
 709                 tty = active;
 710
 711         if (streq(tty, "tty0")) {
 712                 active = mfree(active);
 713
 714                 /* Get the active VC (e.g. tty1) */
 715                 r = read_one_line_file("/sys/class/tty/tty0/active", &active);
 716                 if (r < 0)
 717                         return r;
 718
 719                 tty = active;
 720         }
 721
 722         if (tty != active)
 723                 return strdup_to(ret, tty);
 724
 725         *ret = TAKE_PTR(active);
 726         return 0;
 727 }
 728
 729 int get_kernel_consoles(char ***ret) {
 730         _cleanup_strv_free_ char **l = NULL;
 731         _cleanup_free_ char *line = NULL;
 732         const char *p;
 733         int r;
 734
 735         assert(ret);
 736
 737         /* If /sys is mounted read-only this means we are running in some kind of container environment. In that
 738          * case /sys would reflect the host system, not us, hence ignore the data we can read from it. */
 739         if (path_is_read_only_fs("/sys") > 0)
 740                 goto fallback;
 741
 742         r = read_one_line_file("/sys/class/tty/console/active", &line);
 743         if (r < 0)
 744                 return r;
 745
 746         p = line;
 747         for (;;) {
 748                 _cleanup_free_ char *tty = NULL, *path = NULL;
 749
 750                 r = extract_first_word(&p, &tty, NULL, 0);
 751                 if (r < 0)
 752                         return r;
 753                 if (r == 0)
 754                         break;
 755
 756                 if (streq(tty, "tty0")) {
 757                         tty = mfree(tty);
 758                         r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
 759                         if (r < 0)
 760                                 return r;
 761                 }
 762
 763                 path = path_join("/dev", tty);
 764                 if (!path)
 765                         return -ENOMEM;
 766
 767                 if (access(path, F_OK) < 0) {
 768                         log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
 769                         continue;
 770                 }
 771
 772                 r = strv_consume(&l, TAKE_PTR(path));
 773                 if (r < 0)
 774                         return r;
 775         }
 776
 777         if (strv_isempty(l)) {
 778                 log_debug("No devices found for system console");
 779                 goto fallback;
 780         }
 781
 782         *ret = TAKE_PTR(l);
 783
 784         return 0;
 785
 786 fallback:
 787         r = strv_extend(&l, "/dev/console");
 788         if (r < 0)
 789                 return r;
 790
 791         *ret = TAKE_PTR(l);
 792
 793         return 0;
 794 }
 795
 796 bool tty_is_vc_resolve(const char *tty) {
 797         _cleanup_free_ char *resolved = NULL;
 798
 799         assert(tty);
 800
 801         tty = skip_dev_prefix(tty);
 802
 803         if (streq(tty, "console")) {
 804                 if (resolve_dev_console(&resolved) < 0)
 805                         return false;
 806
 807                 tty = resolved;
 808         }
 809
 810         return tty_is_vc(tty);
 811 }
 812
 813 const char *default_term_for_tty(const char *tty) {
 814         return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220";
 815 }
 816
 817 int fd_columns(int fd) {
 818         struct winsize ws = {};
 819
 820         if (fd < 0)
 821                 return -EBADF;
 822
 823         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 824                 return -errno;
 825
 826         if (ws.ws_col <= 0)
 827                 return -EIO;
 828
 829         return ws.ws_col;
 830 }
 831
 832 unsigned columns(void) {
 833         const char *e;
 834         int c;
 835
 836         if (cached_columns > 0)
 837                 return cached_columns;
 838
 839         c = 0;
 840         e = getenv("COLUMNS");
 841         if (e)
 842                 (void) safe_atoi(e, &c);
 843
 844         if (c <= 0 || c > USHRT_MAX) {
 845                 c = fd_columns(STDOUT_FILENO);
 846                 if (c <= 0)
 847                         c = 80;
 848         }
 849
 850         cached_columns = c;
 851         return cached_columns;
 852 }
 853
 854 int fd_lines(int fd) {
 855         struct winsize ws = {};
 856
 857         if (fd < 0)
 858                 return -EBADF;
 859
 860         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 861                 return -errno;
 862
 863         if (ws.ws_row <= 0)
 864                 return -EIO;
 865
 866         return ws.ws_row;
 867 }
 868
 869 unsigned lines(void) {
 870         const char *e;
 871         int l;
 872
 873         if (cached_lines > 0)
 874                 return cached_lines;
 875
 876         l = 0;
 877         e = getenv("LINES");
 878         if (e)
 879                 (void) safe_atoi(e, &l);
 880
 881         if (l <= 0 || l > USHRT_MAX) {
 882                 l = fd_lines(STDOUT_FILENO);
 883                 if (l <= 0)
 884                         l = 24;
 885         }
 886
 887         cached_lines = l;
 888         return cached_lines;
 889 }
 890
 891 int terminal_set_size_fd(int fd, const char *ident, unsigned rows, unsigned cols) {
 892         struct winsize ws;
 893
 894         if (rows == UINT_MAX && cols == UINT_MAX)
 895                 return 0;
 896
 897         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 898                 return log_debug_errno(errno,
 899                                        "TIOCGWINSZ ioctl for getting %s size failed, not setting terminal size: %m",
 900                                        ident ?: "TTY");
 901
 902         if (rows == UINT_MAX)
 903                 rows = ws.ws_row;
 904         else if (rows > USHRT_MAX)
 905                 rows = USHRT_MAX;
 906
 907         if (cols == UINT_MAX)
 908                 cols = ws.ws_col;
 909         else if (cols > USHRT_MAX)
 910                 cols = USHRT_MAX;
 911
 912         if (rows == ws.ws_row && cols == ws.ws_col)
 913                 return 0;
 914
 915         ws.ws_row = rows;
 916         ws.ws_col = cols;
 917
 918         if (ioctl(fd, TIOCSWINSZ, &ws) < 0)
 919                 return log_debug_errno(errno, "TIOCSWINSZ ioctl for setting %s size failed: %m", ident ?: "TTY");
 920
 921         return 0;
 922 }
 923
 924 int proc_cmdline_tty_size(const char *tty, unsigned *ret_rows, unsigned *ret_cols) {
 925         _cleanup_free_ char *rowskey = NULL, *rowsvalue = NULL, *colskey = NULL, *colsvalue = NULL;
 926         unsigned rows = UINT_MAX, cols = UINT_MAX;
 927         int r;
 928
 929         assert(tty);
 930
 931         if (!ret_rows && !ret_cols)
 932                 return 0;
 933
 934         tty = skip_dev_prefix(tty);
 935         if (!in_charset(tty, ALPHANUMERICAL))
 936                 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "%s contains non-alphanumeric characters", tty);
 937
 938         rowskey = strjoin("systemd.tty.rows.", tty);
 939         if (!rowskey)
 940                 return -ENOMEM;
 941
 942         colskey = strjoin("systemd.tty.columns.", tty);
 943         if (!colskey)
 944                 return -ENOMEM;
 945
 946         r = proc_cmdline_get_key_many(/* flags = */ 0,
 947                                       rowskey, &rowsvalue,
 948                                       colskey, &colsvalue);
 949         if (r < 0)
 950                 return log_debug_errno(r, "Failed to read TTY size of %s from kernel cmdline: %m", tty);
 951
 952         if (rowsvalue) {
 953                 r = safe_atou(rowsvalue, &rows);
 954                 if (r < 0)
 955                         return log_debug_errno(r, "Failed to parse %s=%s: %m", rowskey, rowsvalue);
 956         }
 957
 958         if (colsvalue) {
 959                 r = safe_atou(colsvalue, &cols);
 960                 if (r < 0)
 961                         return log_debug_errno(r, "Failed to parse %s=%s: %m", colskey, colsvalue);
 962         }
 963
 964         if (ret_rows)
 965                 *ret_rows = rows;
 966         if (ret_cols)
 967                 *ret_cols = cols;
 968
 969         return 0;
 970 }
 971
 972 /* intended to be used as a SIGWINCH sighandler */
 973 void columns_lines_cache_reset(int signum) {
 974         cached_columns = 0;
 975         cached_lines = 0;
 976 }
 977
 978 void reset_terminal_feature_caches(void) {
 979         cached_columns = 0;
 980         cached_lines = 0;
 981
 982         cached_color_mode = _COLOR_INVALID;
 983         cached_underline_enabled = -1;
 984         cached_on_tty = -1;
 985         cached_on_dev_null = -1;
 986 }
 987
 988 bool on_tty(void) {
 989
 990         /* We check both stdout and stderr, so that situations where pipes on the shell are used are reliably
 991          * recognized, regardless if only the output or the errors are piped to some place. Since on_tty() is generally
 992          * used to default to a safer, non-interactive, non-color mode of operation it's probably good to be defensive
 993          * here, and check for both. Note that we don't check for STDIN_FILENO, because it should fine to use fancy
 994          * terminal functionality when outputting stuff, even if the input is piped to us. */
 995
 996         if (cached_on_tty < 0)
 997                 cached_on_tty =
 998                         isatty(STDOUT_FILENO) > 0 &&
 999                         isatty(STDERR_FILENO) > 0;
1000
1001         return cached_on_tty;
1002 }
1003
1004 int getttyname_malloc(int fd, char **ret) {
1005         char path[PATH_MAX]; /* PATH_MAX is counted *with* the trailing NUL byte */
1006         int r;
1007
1008         assert(fd >= 0);
1009         assert(ret);
1010
1011         r = ttyname_r(fd, path, sizeof path); /* positive error */
1012         assert(r >= 0);
1013         if (r == ERANGE)
1014                 return -ENAMETOOLONG;
1015         if (r > 0)
1016                 return -r;
1017
1018         return strdup_to(ret, skip_dev_prefix(path));
1019 }
1020
1021 int getttyname_harder(int fd, char **ret) {
1022         _cleanup_free_ char *s = NULL;
1023         int r;
1024
1025         r = getttyname_malloc(fd, &s);
1026         if (r < 0)
1027                 return r;
1028
1029         if (streq(s, "tty"))
1030                 return get_ctty(0, NULL, ret);
1031
1032         *ret = TAKE_PTR(s);
1033         return 0;
1034 }
1035
1036 int get_ctty_devnr(pid_t pid, dev_t *d) {
1037         int r;
1038         _cleanup_free_ char *line = NULL;
1039         const char *p;
1040         unsigned long ttynr;
1041
1042         assert(pid >= 0);
1043
1044         p = procfs_file_alloca(pid, "stat");
1045         r = read_one_line_file(p, &line);
1046         if (r < 0)
1047                 return r;
1048
1049         p = strrchr(line, ')');
1050         if (!p)
1051                 return -EIO;
1052
1053         p++;
1054
1055         if (sscanf(p, " "
1056                    "%*c "  /* state */
1057                    "%*d "  /* ppid */
1058                    "%*d "  /* pgrp */
1059                    "%*d "  /* session */
1060                    "%lu ", /* ttynr */
1061                    &ttynr) != 1)
1062                 return -EIO;
1063
1064         if (devnum_is_zero(ttynr))
1065                 return -ENXIO;
1066
1067         if (d)
1068                 *d = (dev_t) ttynr;
1069
1070         return 0;
1071 }
1072
1073 int get_ctty(pid_t pid, dev_t *ret_devnr, char **ret) {
1074         char pty[STRLEN("/dev/pts/") + DECIMAL_STR_MAX(dev_t) + 1];
1075         _cleanup_free_ char *buf = NULL;
1076         const char *fn = NULL, *w;
1077         dev_t devnr;
1078         int r;
1079
1080         r = get_ctty_devnr(pid, &devnr);
1081         if (r < 0)
1082                 return r;
1083
1084         r = device_path_make_canonical(S_IFCHR, devnr, &buf);
1085         if (r < 0) {
1086                 struct stat st;
1087
1088                 if (r != -ENOENT) /* No symlink for this in /dev/char/? */
1089                         return r;
1090
1091                 /* Maybe this is PTY? PTY devices are not listed in /dev/char/, as they don't follow the
1092                  * Linux device model and hence device_path_make_canonical() doesn't work for them. Let's
1093                  * assume this is a PTY for a moment, and check if the device node this would then map to in
1094                  * /dev/pts/ matches the one we are looking for. This way we don't have to hardcode the major
1095                  * number (which is 136 btw), but we still rely on the fact that PTY numbers map directly to
1096                  * the minor number of the pty. */
1097                 xsprintf(pty, "/dev/pts/%u", minor(devnr));
1098
1099                 if (stat(pty, &st) < 0) {
1100                         if (errno != ENOENT)
1101                                 return -errno;
1102
1103                 } else if (S_ISCHR(st.st_mode) && devnr == st.st_rdev) /* Bingo! */
1104                         fn = pty;
1105
1106                 if (!fn) {
1107                         /* Doesn't exist, or not a PTY? Probably something similar to the PTYs which have no
1108                          * symlink in /dev/char/. Let's return something vaguely useful. */
1109                         r = device_path_make_major_minor(S_IFCHR, devnr, &buf);
1110                         if (r < 0)
1111                                 return r;
1112
1113                         fn = buf;
1114                 }
1115         } else
1116                 fn = buf;
1117
1118         w = path_startswith(fn, "/dev/");
1119         if (!w)
1120                 return -EINVAL;
1121
1122         if (ret) {
1123                 r = strdup_to(ret, w);
1124                 if (r < 0)
1125                         return r;
1126         }
1127
1128         if (ret_devnr)
1129                 *ret_devnr = devnr;
1130
1131         return 0;
1132 }
1133
1134 int ptsname_malloc(int fd, char **ret) {
1135         size_t l = 100;
1136
1137         assert(fd >= 0);
1138         assert(ret);
1139
1140         for (;;) {
1141                 char *c;
1142
1143                 c = new(char, l);
1144                 if (!c)
1145                         return -ENOMEM;
1146
1147                 if (ptsname_r(fd, c, l) == 0) {
1148                         *ret = c;
1149                         return 0;
1150                 }
1151                 if (errno != ERANGE) {
1152                         free(c);
1153                         return -errno;
1154                 }
1155
1156                 free(c);
1157
1158                 if (l > SIZE_MAX / 2)
1159                         return -ENOMEM;
1160
1161                 l *= 2;
1162         }
1163 }
1164
1165 int openpt_allocate(int flags, char **ret_slave) {
1166         _cleanup_close_ int fd = -EBADF;
1167         _cleanup_free_ char *p = NULL;
1168         int r;
1169
1170         fd = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1171         if (fd < 0)
1172                 return -errno;
1173
1174         if (ret_slave) {
1175                 r = ptsname_malloc(fd, &p);
1176                 if (r < 0)
1177                         return r;
1178
1179                 if (!path_startswith(p, "/dev/pts/"))
1180                         return -EINVAL;
1181         }
1182
1183         if (unlockpt(fd) < 0)
1184                 return -errno;
1185
1186         if (ret_slave)
1187                 *ret_slave = TAKE_PTR(p);
1188
1189         return TAKE_FD(fd);
1190 }
1191
1192 static int ptsname_namespace(int pty, char **ret) {
1193         int no = -1, r;
1194
1195         /* Like ptsname(), but doesn't assume that the path is
1196          * accessible in the local namespace. */
1197
1198         r = ioctl(pty, TIOCGPTN, &no);
1199         if (r < 0)
1200                 return -errno;
1201
1202         if (no < 0)
1203                 return -EIO;
1204
1205         if (asprintf(ret, "/dev/pts/%i", no) < 0)
1206                 return -ENOMEM;
1207
1208         return 0;
1209 }
1210
1211 int openpt_allocate_in_namespace(pid_t pid, int flags, char **ret_slave) {
1212         _cleanup_close_ int pidnsfd = -EBADF, mntnsfd = -EBADF, usernsfd = -EBADF, rootfd = -EBADF, fd = -EBADF;
1213         _cleanup_close_pair_ int pair[2] = EBADF_PAIR;
1214         pid_t child;
1215         int r;
1216
1217         assert(pid > 0);
1218
1219         r = namespace_open(pid, &pidnsfd, &mntnsfd, /* ret_netns_fd = */ NULL, &usernsfd, &rootfd);
1220         if (r < 0)
1221                 return r;
1222
1223         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1224                 return -errno;
1225
1226         r = namespace_fork("(sd-openptns)", "(sd-openpt)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGKILL,
1227                            pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child);
1228         if (r < 0)
1229                 return r;
1230         if (r == 0) {
1231                 pair[0] = safe_close(pair[0]);
1232
1233                 fd = openpt_allocate(flags, NULL);
1234                 if (fd < 0)
1235                         _exit(EXIT_FAILURE);
1236
1237                 if (send_one_fd(pair[1], fd, 0) < 0)
1238                         _exit(EXIT_FAILURE);
1239
1240                 _exit(EXIT_SUCCESS);
1241         }
1242
1243         pair[1] = safe_close(pair[1]);
1244
1245         r = wait_for_terminate_and_check("(sd-openptns)", child, 0);
1246         if (r < 0)
1247                 return r;
1248         if (r != EXIT_SUCCESS)
1249                 return -EIO;
1250
1251         fd = receive_one_fd(pair[0], 0);
1252         if (fd < 0)
1253                 return fd;
1254
1255         if (ret_slave) {
1256                 r = ptsname_namespace(fd, ret_slave);
1257                 if (r < 0)
1258                         return r;
1259         }
1260
1261         return TAKE_FD(fd);
1262 }
1263
1264 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1265         _cleanup_close_ int pidnsfd = -EBADF, mntnsfd = -EBADF, usernsfd = -EBADF, rootfd = -EBADF;
1266         _cleanup_close_pair_ int pair[2] = EBADF_PAIR;
1267         pid_t child;
1268         int r;
1269
1270         r = namespace_open(pid, &pidnsfd, &mntnsfd, /* ret_netns_fd = */ NULL, &usernsfd, &rootfd);
1271         if (r < 0)
1272                 return r;
1273
1274         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1275                 return -errno;
1276
1277         r = namespace_fork("(sd-terminalns)", "(sd-terminal)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGKILL,
1278                            pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child);
1279         if (r < 0)
1280                 return r;
1281         if (r == 0) {
1282                 int master;
1283
1284                 pair[0] = safe_close(pair[0]);
1285
1286                 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1287                 if (master < 0)
1288                         _exit(EXIT_FAILURE);
1289
1290                 if (send_one_fd(pair[1], master, 0) < 0)
1291                         _exit(EXIT_FAILURE);
1292
1293                 _exit(EXIT_SUCCESS);
1294         }
1295
1296         pair[1] = safe_close(pair[1]);
1297
1298         r = wait_for_terminate_and_check("(sd-terminalns)", child, 0);
1299         if (r < 0)
1300                 return r;
1301         if (r != EXIT_SUCCESS)
1302                 return -EIO;
1303
1304         return receive_one_fd(pair[0], 0);
1305 }
1306
1307 static bool on_dev_null(void) {
1308         struct stat dst, ost, est;
1309
1310         if (cached_on_dev_null >= 0)
1311                 return cached_on_dev_null;
1312
1313         if (stat("/dev/null", &dst) < 0 || fstat(STDOUT_FILENO, &ost) < 0 || fstat(STDERR_FILENO, &est) < 0)
1314                 cached_on_dev_null = false;
1315         else
1316                 cached_on_dev_null = stat_inode_same(&dst, &ost) && stat_inode_same(&dst, &est);
1317
1318         return cached_on_dev_null;
1319 }
1320
1321 bool getenv_terminal_is_dumb(void) {
1322         const char *e;
1323
1324         e = getenv("TERM");
1325         if (!e)
1326                 return true;
1327
1328         return streq(e, "dumb");
1329 }
1330
1331 bool terminal_is_dumb(void) {
1332         if (!on_tty() && !on_dev_null())
1333                 return true;
1334
1335         return getenv_terminal_is_dumb();
1336 }
1337
1338 static ColorMode parse_systemd_colors(void) {
1339         const char *e;
1340         int r;
1341
1342         e = getenv("SYSTEMD_COLORS");
1343         if (!e)
1344                 return _COLOR_INVALID;
1345         if (streq(e, "16"))
1346                 return COLOR_16;
1347         if (streq(e, "256"))
1348                 return COLOR_256;
1349         r = parse_boolean(e);
1350         if (r >= 0)
1351                 return r > 0 ? COLOR_ON : COLOR_OFF;
1352         return _COLOR_INVALID;
1353 }
1354
1355 ColorMode get_color_mode(void) {
1356
1357         /* Returns the mode used to choose output colors. The possible modes are COLOR_OFF for no colors,
1358          * COLOR_16 for only the base 16 ANSI colors, COLOR_256 for more colors and COLOR_ON for unrestricted
1359          * color output. For that we check $SYSTEMD_COLORS first (which is the explicit way to
1360          * 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
1361          * 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
1362          * check whether we are connected to a TTY, because we don't keep /dev/console open continuously due to fear
1363          * of SAK, and hence things are a bit weird. */
1364         ColorMode m;
1365
1366         if (cached_color_mode < 0) {
1367                 m = parse_systemd_colors();
1368                 if (m >= 0)
1369                         cached_color_mode = m;
1370                 else if (getenv("NO_COLOR"))
1371                         /* We only check for the presence of the variable; value is ignored. */
1372                         cached_color_mode = COLOR_OFF;
1373
1374                 else if (getpid_cached() == 1) {
1375                         /* PID1 outputs to the console without holding it open all the time.
1376                          *
1377                          * Note that the Linux console can only display 16 colors. We still enable 256 color
1378                          * mode even for PID1 output though (which typically goes to the Linux console),
1379                          * since the Linux console is able to parse the 256 color sequences and automatically
1380                          * map them to the closest color in the 16 color palette (since kernel 3.16). Doing
1381                          * 256 colors is nice for people who invoke systemd in a container or via a serial
1382                          * link or such, and use a true 256 color terminal to do so. */
1383                         if (getenv_terminal_is_dumb())
1384                                 cached_color_mode = COLOR_OFF;
1385                 } else {
1386                         if (terminal_is_dumb())
1387                                 cached_color_mode = COLOR_OFF;
1388                 }
1389
1390                 if (cached_color_mode < 0) {
1391                         /* We failed to figure out any reason to *disable* colors.
1392                          * Let's see how many colors we shall use. */
1393                         if (STRPTR_IN_SET(getenv("COLORTERM"),
1394                                           "truecolor",
1395                                           "24bit"))
1396                                 cached_color_mode = COLOR_24BIT;
1397                         else
1398                                 cached_color_mode = COLOR_256;
1399                 }
1400         }
1401
1402         return cached_color_mode;
1403 }
1404
1405 bool dev_console_colors_enabled(void) {
1406         _cleanup_free_ char *s = NULL;
1407         ColorMode m;
1408
1409         /* Returns true if we assume that color is supported on /dev/console.
1410          *
1411          * For that we first check if we explicitly got told to use colors or not, by checking $SYSTEMD_COLORS. If that
1412          * isn't set we check whether PID 1 has $TERM set, and if not, whether TERM is set on the kernel command
1413          * line. If we find $TERM set we assume color if it's not set to "dumb", similarly to how regular
1414          * colors_enabled() operates. */
1415
1416         m = parse_systemd_colors();
1417         if (m >= 0)
1418                 return m;
1419
1420         if (getenv("NO_COLOR"))
1421                 return false;
1422
1423         if (getenv_for_pid(1, "TERM", &s) <= 0)
1424                 (void) proc_cmdline_get_key("TERM", 0, &s);
1425
1426         return !streq_ptr(s, "dumb");
1427 }
1428
1429 bool underline_enabled(void) {
1430
1431         if (cached_underline_enabled < 0) {
1432
1433                 /* The Linux console doesn't support underlining, turn it off, but only there. */
1434
1435                 if (colors_enabled())
1436                         cached_underline_enabled = !streq_ptr(getenv("TERM"), "linux");
1437                 else
1438                         cached_underline_enabled = false;
1439         }
1440
1441         return cached_underline_enabled;
1442 }
1443
1444 int vt_default_utf8(void) {
1445         _cleanup_free_ char *b = NULL;
1446         int r;
1447
1448         /* Read the default VT UTF8 setting from the kernel */
1449
1450         r = read_one_line_file("/sys/module/vt/parameters/default_utf8", &b);
1451         if (r < 0)
1452                 return r;
1453
1454         return parse_boolean(b);
1455 }
1456
1457 int vt_reset_keyboard(int fd) {
1458         int kb;
1459
1460         /* If we can't read the default, then default to unicode. It's 2017 after all. */
1461         kb = vt_default_utf8() != 0 ? K_UNICODE : K_XLATE;
1462
1463         return RET_NERRNO(ioctl(fd, KDSKBMODE, kb));
1464 }
1465
1466 int vt_restore(int fd) {
1467
1468         static const struct vt_mode mode = {
1469                 .mode = VT_AUTO,
1470         };
1471
1472         int r, ret = 0;
1473
1474         assert(fd >= 0);
1475
1476         if (!isatty_safe(fd))
1477                 return log_debug_errno(errno, "Asked to restore the VT for an fd that does not refer to a terminal: %m");
1478
1479         if (ioctl(fd, KDSETMODE, KD_TEXT) < 0)
1480                 RET_GATHER(ret, log_debug_errno(errno, "Failed to set VT to text mode, ignoring: %m"));
1481
1482         r = vt_reset_keyboard(fd);
1483         if (r < 0)
1484                 RET_GATHER(ret, log_debug_errno(r, "Failed to reset keyboard mode, ignoring: %m"));
1485
1486         if (ioctl(fd, VT_SETMODE, &mode) < 0)
1487                 RET_GATHER(ret, log_debug_errno(errno, "Failed to set VT_AUTO mode, ignoring: %m"));
1488
1489         r = fchmod_and_chown(fd, TTY_MODE, 0, GID_INVALID);
1490         if (r < 0)
1491                 RET_GATHER(ret, log_debug_errno(r, "Failed to chmod()/chown() VT, ignoring: %m"));
1492
1493         return ret;
1494 }
1495
1496 int vt_release(int fd, bool restore) {
1497         assert(fd >= 0);
1498
1499         /* This function releases the VT by acknowledging the VT-switch signal
1500          * sent by the kernel and optionally reset the VT in text and auto
1501          * VT-switching modes. */
1502
1503         if (!isatty_safe(fd))
1504                 return log_debug_errno(errno, "Asked to release the VT for an fd that does not refer to a terminal: %m");
1505
1506         if (ioctl(fd, VT_RELDISP, 1) < 0)
1507                 return -errno;
1508
1509         if (restore)
1510                 return vt_restore(fd);
1511
1512         return 0;
1513 }
1514
1515 void get_log_colors(int priority, const char **on, const char **off, const char **highlight) {
1516         /* Note that this will initialize output variables only when there's something to output.
1517          * The caller must pre-initialize to "" or NULL as appropriate. */
1518
1519         if (priority <= LOG_ERR) {
1520                 if (on)
1521                         *on = ansi_highlight_red();
1522                 if (off)
1523                         *off = ansi_normal();
1524                 if (highlight)
1525                         *highlight = ansi_highlight();
1526
1527         } else if (priority <= LOG_WARNING) {
1528                 if (on)
1529                         *on = ansi_highlight_yellow();
1530                 if (off)
1531                         *off = ansi_normal();
1532                 if (highlight)
1533                         *highlight = ansi_highlight();
1534
1535         } else if (priority <= LOG_NOTICE) {
1536                 if (on)
1537                         *on = ansi_highlight();
1538                 if (off)
1539                         *off = ansi_normal();
1540                 if (highlight)
1541                         *highlight = ansi_highlight_red();
1542
1543         } else if (priority >= LOG_DEBUG) {
1544                 if (on)
1545                         *on = ansi_grey();
1546                 if (off)
1547                         *off = ansi_normal();
1548                 if (highlight)
1549                         *highlight = ansi_highlight_red();
1550         }
1551 }
1552
1553 int set_terminal_cursor_position(int fd, unsigned int row, unsigned int column) {
1554         int r;
1555         char cursor_position[STRLEN("\x1B[") + DECIMAL_STR_MAX(int) * 2 + STRLEN(";H") + 1];
1556
1557         assert(fd >= 0);
1558
1559         xsprintf(cursor_position, "\x1B[%u;%uH", row, column);
1560
1561         r = loop_write(fd, cursor_position, SIZE_MAX);
1562         if (r < 0)
1563                 return log_warning_errno(r, "Failed to set cursor position, ignoring: %m");
1564
1565         return 0;
1566 }
1567
1568 void termios_disable_echo(struct termios *termios) {
1569         assert(termios);
1570
1571         termios->c_lflag &= ~(ICANON|ECHO);
1572         termios->c_cc[VMIN] = 1;
1573         termios->c_cc[VTIME] = 0;
1574 }
1575
1576 typedef enum BackgroundColorState {
1577         BACKGROUND_TEXT,
1578         BACKGROUND_ESCAPE,
1579         BACKGROUND_BRACKET,
1580         BACKGROUND_FIRST_ONE,
1581         BACKGROUND_SECOND_ONE,
1582         BACKGROUND_SEMICOLON,
1583         BACKGROUND_R,
1584         BACKGROUND_G,
1585         BACKGROUND_B,
1586         BACKGROUND_RED,
1587         BACKGROUND_GREEN,
1588         BACKGROUND_BLUE,
1589         BACKGROUND_STRING_TERMINATOR,
1590 } BackgroundColorState;
1591
1592 typedef struct BackgroundColorContext {
1593         BackgroundColorState state;
1594         uint32_t red, green, blue;
1595         unsigned red_bits, green_bits, blue_bits;
1596 } BackgroundColorContext;
1597
1598 static int scan_background_color_response(
1599                 BackgroundColorContext *context,
1600                 const char *buf,
1601                 size_t size) {
1602
1603         assert(context);
1604         assert(buf || size == 0);
1605
1606         for (size_t i = 0; i < size; i++) {
1607                 char c = buf[i];
1608
1609                 switch (context->state) {
1610
1611                 case BACKGROUND_TEXT:
1612                         context->state = c == '\x1B' ? BACKGROUND_ESCAPE : BACKGROUND_TEXT;
1613                         break;
1614
1615                 case BACKGROUND_ESCAPE:
1616                         context->state = c == ']' ? BACKGROUND_BRACKET : BACKGROUND_TEXT;
1617                         break;
1618
1619                 case BACKGROUND_BRACKET:
1620                         context->state = c == '1' ? BACKGROUND_FIRST_ONE : BACKGROUND_TEXT;
1621                         break;
1622
1623                 case BACKGROUND_FIRST_ONE:
1624                         context->state = c == '1' ? BACKGROUND_SECOND_ONE : BACKGROUND_TEXT;
1625                         break;
1626
1627                 case BACKGROUND_SECOND_ONE:
1628                         context->state = c == ';' ? BACKGROUND_SEMICOLON : BACKGROUND_TEXT;
1629                         break;
1630
1631                 case BACKGROUND_SEMICOLON:
1632                         context->state = c == 'r' ? BACKGROUND_R : BACKGROUND_TEXT;
1633                         break;
1634
1635                 case BACKGROUND_R:
1636                         context->state = c == 'g' ? BACKGROUND_G : BACKGROUND_TEXT;
1637                         break;
1638
1639                 case BACKGROUND_G:
1640                         context->state = c == 'b' ? BACKGROUND_B : BACKGROUND_TEXT;
1641                         break;
1642
1643                 case BACKGROUND_B:
1644                         context->state = c == ':' ? BACKGROUND_RED : BACKGROUND_TEXT;
1645                         break;
1646
1647                 case BACKGROUND_RED:
1648                         if (c == '/')
1649                                 context->state = context->red_bits > 0 ? BACKGROUND_GREEN : BACKGROUND_TEXT;
1650                         else {
1651                                 int d = unhexchar(c);
1652                                 if (d < 0 || context->red_bits >= sizeof(context->red)*8)
1653                                         context->state = BACKGROUND_TEXT;
1654                                 else {
1655                                         context->red = (context->red << 4) | d;
1656                                         context->red_bits += 4;
1657                                 }
1658                         }
1659                         break;
1660
1661                 case BACKGROUND_GREEN:
1662                         if (c == '/')
1663                                 context->state = context->green_bits > 0 ? BACKGROUND_BLUE : BACKGROUND_TEXT;
1664                         else {
1665                                 int d = unhexchar(c);
1666                                 if (d < 0 || context->green_bits >= sizeof(context->green)*8)
1667                                         context->state = BACKGROUND_TEXT;
1668                                 else {
1669                                         context->green = (context->green << 4) | d;
1670                                         context->green_bits += 4;
1671                                 }
1672                         }
1673                         break;
1674
1675                 case BACKGROUND_BLUE:
1676                         if (c == '\x07') {
1677                                 if (context->blue_bits > 0)
1678                                         return 1; /* success! */
1679
1680                                 context->state = BACKGROUND_TEXT;
1681                         } else if (c == '\x1b')
1682                                 context->state = context->blue_bits > 0 ? BACKGROUND_STRING_TERMINATOR : BACKGROUND_TEXT;
1683                         else {
1684                                 int d = unhexchar(c);
1685                                 if (d < 0 || context->blue_bits >= sizeof(context->blue)*8)
1686                                         context->state = BACKGROUND_TEXT;
1687                                 else {
1688                                         context->blue = (context->blue << 4) | d;
1689                                         context->blue_bits += 4;
1690                                 }
1691                         }
1692                         break;
1693
1694                 case BACKGROUND_STRING_TERMINATOR:
1695                         if (c == '\\')
1696                                 return 1; /* success! */
1697
1698                         context->state = c == ']' ? BACKGROUND_ESCAPE : BACKGROUND_TEXT;
1699                         break;
1700
1701                 }
1702
1703                 /* Reset any colors we might have picked up */
1704                 if (IN_SET(context->state, BACKGROUND_TEXT, BACKGROUND_ESCAPE)) {
1705                         /* reset color */
1706                         context->red = context->green = context->blue = 0;
1707                         context->red_bits = context->green_bits = context->blue_bits = 0;
1708                 }
1709         }
1710
1711         return 0; /* all good, but not enough data yet */
1712 }
1713
1714 int get_default_background_color(double *ret_red, double *ret_green, double *ret_blue) {
1715         int r;
1716
1717         assert(ret_red);
1718         assert(ret_green);
1719         assert(ret_blue);
1720
1721         if (!colors_enabled())
1722                 return -EOPNOTSUPP;
1723
1724         if (!isatty(STDIN_FILENO) || !isatty(STDOUT_FILENO))
1725                 return -EOPNOTSUPP;
1726
1727         if (streq_ptr(getenv("TERM"), "linux")) {
1728                 /* Linux console is black */
1729                 *ret_red = *ret_green = *ret_blue = 0.0;
1730                 return 0;
1731         }
1732
1733         struct termios old_termios;
1734         if (tcgetattr(STDIN_FILENO, &old_termios) < 0)
1735                 return -errno;
1736
1737         struct termios new_termios = old_termios;
1738         termios_disable_echo(&new_termios);
1739
1740         if (tcsetattr(STDOUT_FILENO, TCSADRAIN, &new_termios) < 0)
1741                 return -errno;
1742
1743         r = loop_write(STDOUT_FILENO, "\x1B]11;?\x07", SIZE_MAX);
1744         if (r < 0)
1745                 goto finish;
1746
1747         usec_t end = usec_add(now(CLOCK_MONOTONIC), 100 * USEC_PER_MSEC);
1748         char buf[256];
1749         size_t buf_full = 0;
1750         BackgroundColorContext context = {};
1751
1752         for (;;) {
1753                 usec_t n = now(CLOCK_MONOTONIC);
1754
1755                 if (n >= end) {
1756                         r = -EOPNOTSUPP;
1757                         goto finish;
1758                 }
1759
1760                 r = fd_wait_for_event(STDIN_FILENO, POLLIN, usec_sub_unsigned(end, n));
1761                 if (r < 0)
1762                         goto finish;
1763                 if (r == 0) {
1764                         r = -EOPNOTSUPP;
1765                         goto finish;
1766                 }
1767
1768                 ssize_t l;
1769                 l = read(STDIN_FILENO, buf, sizeof(buf) - buf_full);
1770                 if (l < 0) {
1771                         r = -errno;
1772                         goto finish;
1773                 }
1774
1775                 buf_full += l;
1776                 assert(buf_full <= sizeof(buf));
1777
1778                 r = scan_background_color_response(&context, buf, buf_full);
1779                 if (r < 0)
1780                         goto finish;
1781                 if (r > 0) {
1782                         assert(context.red_bits > 0);
1783                         *ret_red = (double) context.red / ((UINT64_C(1) << context.red_bits) - 1);
1784                         assert(context.green_bits > 0);
1785                         *ret_green = (double) context.green / ((UINT64_C(1) << context.green_bits) - 1);
1786                         assert(context.blue_bits > 0);
1787                         *ret_blue = (double) context.blue / ((UINT64_C(1) << context.blue_bits) - 1);
1788                         r = 0;
1789                         goto finish;
1790                 }
1791         }
1792
1793 finish:
1794         (void) tcsetattr(STDOUT_FILENO, TCSADRAIN, &old_termios);
1795         return r;
1796 }