src/basic/terminal-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <limits.h>
   6 #include <linux/kd.h>
   7 #include <linux/tiocl.h>
   8 #include <linux/vt.h>
   9 #include <poll.h>
  10 #include <signal.h>
  11 #include <stdarg.h>
  12 #include <stddef.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <sys/inotify.h>
  16 #include <sys/ioctl.h>
  17 #include <sys/socket.h>
  18 #include <sys/sysmacros.h>
  19 #include <sys/time.h>
  20 #include <sys/types.h>
  21 #include <sys/utsname.h>
  22 #include <termios.h>
  23 #include <unistd.h>
  24
  25 #include "alloc-util.h"
  26 #include "copy.h"
  27 #include "def.h"
  28 #include "env-util.h"
  29 #include "fd-util.h"
  30 #include "fileio.h"
  31 #include "fs-util.h"
  32 #include "io-util.h"
  33 #include "log.h"
  34 #include "macro.h"
  35 #include "pager.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 "string-util.h"
  43 #include "strv.h"
  44 #include "terminal-util.h"
  45 #include "time-util.h"
  46 #include "util.h"
  47
  48 static volatile unsigned cached_columns = 0;
  49 static volatile unsigned cached_lines = 0;
  50
  51 static volatile int cached_on_tty = -1;
  52 static volatile int cached_colors_enabled = -1;
  53 static volatile int cached_underline_enabled = -1;
  54
  55 int chvt(int vt) {
  56         _cleanup_close_ int fd;
  57
  58         /* Switch to the specified vt number. If the VT is specified <= 0 switch to the VT the kernel log messages go,
  59          * if that's configured. */
  60
  61         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
  62         if (fd < 0)
  63                 return -errno;
  64
  65         if (vt <= 0) {
  66                 int tiocl[2] = {
  67                         TIOCL_GETKMSGREDIRECT,
  68                         0
  69                 };
  70
  71                 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
  72                         return -errno;
  73
  74                 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
  75         }
  76
  77         if (ioctl(fd, VT_ACTIVATE, vt) < 0)
  78                 return -errno;
  79
  80         return 0;
  81 }
  82
  83 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
  84         struct termios old_termios, new_termios;
  85         char c, line[LINE_MAX];
  86
  87         assert(f);
  88         assert(ret);
  89
  90         if (tcgetattr(fileno(f), &old_termios) >= 0) {
  91                 new_termios = old_termios;
  92
  93                 new_termios.c_lflag &= ~ICANON;
  94                 new_termios.c_cc[VMIN] = 1;
  95                 new_termios.c_cc[VTIME] = 0;
  96
  97                 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
  98                         size_t k;
  99
 100                         if (t != USEC_INFINITY) {
 101                                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
 102                                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 103                                         return -ETIMEDOUT;
 104                                 }
 105                         }
 106
 107                         k = fread(&c, 1, 1, f);
 108
 109                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 110
 111                         if (k <= 0)
 112                                 return -EIO;
 113
 114                         if (need_nl)
 115                                 *need_nl = c != '\n';
 116
 117                         *ret = c;
 118                         return 0;
 119                 }
 120         }
 121
 122         if (t != USEC_INFINITY) {
 123                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
 124                         return -ETIMEDOUT;
 125         }
 126
 127         errno = 0;
 128         if (!fgets(line, sizeof(line), f))
 129                 return errno > 0 ? -errno : -EIO;
 130
 131         truncate_nl(line);
 132
 133         if (strlen(line) != 1)
 134                 return -EBADMSG;
 135
 136         if (need_nl)
 137                 *need_nl = false;
 138
 139         *ret = line[0];
 140         return 0;
 141 }
 142
 143 #define DEFAULT_ASK_REFRESH_USEC (2*USEC_PER_SEC)
 144
 145 int ask_char(char *ret, const char *replies, const char *fmt, ...) {
 146         int r;
 147
 148         assert(ret);
 149         assert(replies);
 150         assert(fmt);
 151
 152         for (;;) {
 153                 va_list ap;
 154                 char c;
 155                 bool need_nl = true;
 156
 157                 if (colors_enabled())
 158                         fputs(ANSI_HIGHLIGHT, stdout);
 159
 160                 putchar('\r');
 161
 162                 va_start(ap, fmt);
 163                 vprintf(fmt, ap);
 164                 va_end(ap);
 165
 166                 if (colors_enabled())
 167                         fputs(ANSI_NORMAL, stdout);
 168
 169                 fflush(stdout);
 170
 171                 r = read_one_char(stdin, &c, DEFAULT_ASK_REFRESH_USEC, &need_nl);
 172                 if (r < 0) {
 173
 174                         if (r == -ETIMEDOUT)
 175                                 continue;
 176
 177                         if (r == -EBADMSG) {
 178                                 puts("Bad input, please try again.");
 179                                 continue;
 180                         }
 181
 182                         putchar('\n');
 183                         return r;
 184                 }
 185
 186                 if (need_nl)
 187                         putchar('\n');
 188
 189                 if (strchr(replies, c)) {
 190                         *ret = c;
 191                         return 0;
 192                 }
 193
 194                 puts("Read unexpected character, please try again.");
 195         }
 196 }
 197
 198 int ask_string(char **ret, const char *text, ...) {
 199         assert(ret);
 200         assert(text);
 201
 202         for (;;) {
 203                 char line[LINE_MAX];
 204                 va_list ap;
 205
 206                 if (colors_enabled())
 207                         fputs(ANSI_HIGHLIGHT, stdout);
 208
 209                 va_start(ap, text);
 210                 vprintf(text, ap);
 211                 va_end(ap);
 212
 213                 if (colors_enabled())
 214                         fputs(ANSI_NORMAL, stdout);
 215
 216                 fflush(stdout);
 217
 218                 errno = 0;
 219                 if (!fgets(line, sizeof(line), stdin))
 220                         return errno > 0 ? -errno : -EIO;
 221
 222                 if (!endswith(line, "\n"))
 223                         putchar('\n');
 224                 else {
 225                         char *s;
 226
 227                         if (isempty(line))
 228                                 continue;
 229
 230                         truncate_nl(line);
 231                         s = strdup(line);
 232                         if (!s)
 233                                 return -ENOMEM;
 234
 235                         *ret = s;
 236                         return 0;
 237                 }
 238         }
 239 }
 240
 241 int reset_terminal_fd(int fd, bool switch_to_text) {
 242         struct termios termios;
 243         int r = 0;
 244
 245         /* Set terminal to some sane defaults */
 246
 247         assert(fd >= 0);
 248
 249         /* We leave locked terminal attributes untouched, so that
 250          * Plymouth may set whatever it wants to set, and we don't
 251          * interfere with that. */
 252
 253         /* Disable exclusive mode, just in case */
 254         (void) ioctl(fd, TIOCNXCL);
 255
 256         /* Switch to text mode */
 257         if (switch_to_text)
 258                 (void) ioctl(fd, KDSETMODE, KD_TEXT);
 259
 260         /* Set default keyboard mode */
 261         (void) vt_reset_keyboard(fd);
 262
 263         if (tcgetattr(fd, &termios) < 0) {
 264                 r = -errno;
 265                 goto finish;
 266         }
 267
 268         /* We only reset the stuff that matters to the software. How
 269          * hardware is set up we don't touch assuming that somebody
 270          * else will do that for us */
 271
 272         termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
 273         termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
 274         termios.c_oflag |= ONLCR;
 275         termios.c_cflag |= CREAD;
 276         termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
 277
 278         termios.c_cc[VINTR]    =   03;  /* ^C */
 279         termios.c_cc[VQUIT]    =  034;  /* ^\ */
 280         termios.c_cc[VERASE]   = 0177;
 281         termios.c_cc[VKILL]    =  025;  /* ^X */
 282         termios.c_cc[VEOF]     =   04;  /* ^D */
 283         termios.c_cc[VSTART]   =  021;  /* ^Q */
 284         termios.c_cc[VSTOP]    =  023;  /* ^S */
 285         termios.c_cc[VSUSP]    =  032;  /* ^Z */
 286         termios.c_cc[VLNEXT]   =  026;  /* ^V */
 287         termios.c_cc[VWERASE]  =  027;  /* ^W */
 288         termios.c_cc[VREPRINT] =  022;  /* ^R */
 289         termios.c_cc[VEOL]     =    0;
 290         termios.c_cc[VEOL2]    =    0;
 291
 292         termios.c_cc[VTIME]  = 0;
 293         termios.c_cc[VMIN]   = 1;
 294
 295         if (tcsetattr(fd, TCSANOW, &termios) < 0)
 296                 r = -errno;
 297
 298 finish:
 299         /* Just in case, flush all crap out */
 300         (void) tcflush(fd, TCIOFLUSH);
 301
 302         return r;
 303 }
 304
 305 int reset_terminal(const char *name) {
 306         _cleanup_close_ int fd = -1;
 307
 308         /* We open the terminal with O_NONBLOCK here, to ensure we
 309          * don't block on carrier if this is a terminal with carrier
 310          * configured. */
 311
 312         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 313         if (fd < 0)
 314                 return fd;
 315
 316         return reset_terminal_fd(fd, true);
 317 }
 318
 319 int open_terminal(const char *name, int mode) {
 320         unsigned c = 0;
 321         int fd;
 322
 323         /*
 324          * If a TTY is in the process of being closed opening it might
 325          * cause EIO. This is horribly awful, but unlikely to be
 326          * changed in the kernel. Hence we work around this problem by
 327          * retrying a couple of times.
 328          *
 329          * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
 330          */
 331
 332         if (mode & O_CREAT)
 333                 return -EINVAL;
 334
 335         for (;;) {
 336                 fd = open(name, mode, 0);
 337                 if (fd >= 0)
 338                         break;
 339
 340                 if (errno != EIO)
 341                         return -errno;
 342
 343                 /* Max 1s in total */
 344                 if (c >= 20)
 345                         return -errno;
 346
 347                 usleep(50 * USEC_PER_MSEC);
 348                 c++;
 349         }
 350
 351         if (isatty(fd) <= 0) {
 352                 safe_close(fd);
 353                 return -ENOTTY;
 354         }
 355
 356         return fd;
 357 }
 358
 359 int acquire_terminal(
 360                 const char *name,
 361                 AcquireTerminalFlags flags,
 362                 usec_t timeout) {
 363
 364         _cleanup_close_ int notify = -1, fd = -1;
 365         usec_t ts = USEC_INFINITY;
 366         int r, wd = -1;
 367
 368         assert(name);
 369         assert(IN_SET(flags & ~ACQUIRE_TERMINAL_PERMISSIVE, ACQUIRE_TERMINAL_TRY, ACQUIRE_TERMINAL_FORCE, ACQUIRE_TERMINAL_WAIT));
 370
 371         /* We use inotify to be notified when the tty is closed. We create the watch before checking if we can actually
 372          * acquire it, so that we don't lose any event.
 373          *
 374          * Note: strictly speaking this actually watches for the device being closed, it does *not* really watch
 375          * whether a tty loses its controlling process. However, unless some rogue process uses TIOCNOTTY on /dev/tty
 376          * *after* closing its tty otherwise this will not become a problem. As long as the administrator makes sure to
 377          * not configure any service on the same tty as an untrusted user this should not be a problem. (Which they
 378          * probably should not do anyway.) */
 379
 380         if ((flags & ~ACQUIRE_TERMINAL_PERMISSIVE) == ACQUIRE_TERMINAL_WAIT) {
 381                 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
 382                 if (notify < 0)
 383                         return -errno;
 384
 385                 wd = inotify_add_watch(notify, name, IN_CLOSE);
 386                 if (wd < 0)
 387                         return -errno;
 388
 389                 if (timeout != USEC_INFINITY)
 390                         ts = now(CLOCK_MONOTONIC);
 391         }
 392
 393         for (;;) {
 394                 struct sigaction sa_old, sa_new = {
 395                         .sa_handler = SIG_IGN,
 396                         .sa_flags = SA_RESTART,
 397                 };
 398
 399                 if (notify >= 0) {
 400                         r = flush_fd(notify);
 401                         if (r < 0)
 402                                 return r;
 403                 }
 404
 405                 /* We pass here O_NOCTTY only so that we can check the return value TIOCSCTTY and have a reliable way
 406                  * to figure out if we successfully became the controlling process of the tty */
 407                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 408                 if (fd < 0)
 409                         return fd;
 410
 411                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed if we already own the tty. */
 412                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 413
 414                 /* First, try to get the tty */
 415                 r = ioctl(fd, TIOCSCTTY,
 416                           (flags & ~ACQUIRE_TERMINAL_PERMISSIVE) == ACQUIRE_TERMINAL_FORCE) < 0 ? -errno : 0;
 417
 418                 /* Reset signal handler to old value */
 419                 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 420
 421                 /* Success? Exit the loop now! */
 422                 if (r >= 0)
 423                         break;
 424
 425                 /* Any failure besides -EPERM? Fail, regardless of the mode. */
 426                 if (r != -EPERM)
 427                         return r;
 428
 429                 if (flags & ACQUIRE_TERMINAL_PERMISSIVE) /* If we are in permissive mode, then EPERM is fine, turn this
 430                                                           * into a success. Note that EPERM is also returned if we
 431                                                           * already are the owner of the TTY. */
 432                         break;
 433
 434                 if (flags != ACQUIRE_TERMINAL_WAIT) /* If we are in TRY or FORCE mode, then propagate EPERM as EPERM */
 435                         return r;
 436
 437                 assert(notify >= 0);
 438                 assert(wd >= 0);
 439
 440                 for (;;) {
 441                         union inotify_event_buffer buffer;
 442                         struct inotify_event *e;
 443                         ssize_t l;
 444
 445                         if (timeout != USEC_INFINITY) {
 446                                 usec_t n;
 447
 448                                 assert(ts != USEC_INFINITY);
 449
 450                                 n = now(CLOCK_MONOTONIC);
 451                                 if (ts + timeout < n)
 452                                         return -ETIMEDOUT;
 453
 454                                 r = fd_wait_for_event(notify, POLLIN, ts + timeout - n);
 455                                 if (r < 0)
 456                                         return r;
 457                                 if (r == 0)
 458                                         return -ETIMEDOUT;
 459                         }
 460
 461                         l = read(notify, &buffer, sizeof(buffer));
 462                         if (l < 0) {
 463                                 if (IN_SET(errno, EINTR, EAGAIN))
 464                                         continue;
 465
 466                                 return -errno;
 467                         }
 468
 469                         FOREACH_INOTIFY_EVENT(e, buffer, l) {
 470                                 if (e->mask & IN_Q_OVERFLOW) /* If we hit an inotify queue overflow, simply check if the terminal is up for grabs now. */
 471                                         break;
 472
 473                                 if (e->wd != wd || !(e->mask & IN_CLOSE)) /* Safety checks */
 474                                         return -EIO;
 475                         }
 476
 477                         break;
 478                 }
 479
 480                 /* We close the tty fd here since if the old session ended our handle will be dead. It's important that
 481                  * we do this after sleeping, so that we don't enter an endless loop. */
 482                 fd = safe_close(fd);
 483         }
 484
 485         return TAKE_FD(fd);
 486 }
 487
 488 int release_terminal(void) {
 489         static const struct sigaction sa_new = {
 490                 .sa_handler = SIG_IGN,
 491                 .sa_flags = SA_RESTART,
 492         };
 493
 494         _cleanup_close_ int fd = -1;
 495         struct sigaction sa_old;
 496         int r;
 497
 498         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 499         if (fd < 0)
 500                 return -errno;
 501
 502         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 503          * by our own TIOCNOTTY */
 504         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 505
 506         r = ioctl(fd, TIOCNOTTY) < 0 ? -errno : 0;
 507
 508         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 509
 510         return r;
 511 }
 512
 513 int terminal_vhangup_fd(int fd) {
 514         assert(fd >= 0);
 515
 516         if (ioctl(fd, TIOCVHANGUP) < 0)
 517                 return -errno;
 518
 519         return 0;
 520 }
 521
 522 int terminal_vhangup(const char *name) {
 523         _cleanup_close_ int fd;
 524
 525         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 526         if (fd < 0)
 527                 return fd;
 528
 529         return terminal_vhangup_fd(fd);
 530 }
 531
 532 int vt_disallocate(const char *name) {
 533         _cleanup_close_ int fd = -1;
 534         const char *e, *n;
 535         unsigned u;
 536         int r;
 537
 538         /* Deallocate the VT if possible. If not possible
 539          * (i.e. because it is the active one), at least clear it
 540          * entirely (including the scrollback buffer) */
 541
 542         e = path_startswith(name, "/dev/");
 543         if (!e)
 544                 return -EINVAL;
 545
 546         if (!tty_is_vc(name)) {
 547                 /* So this is not a VT. I guess we cannot deallocate
 548                  * it then. But let's at least clear the screen */
 549
 550                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 551                 if (fd < 0)
 552                         return fd;
 553
 554                 loop_write(fd,
 555                            "\033[r"    /* clear scrolling region */
 556                            "\033[H"    /* move home */
 557                            "\033[2J",  /* clear screen */
 558                            10, false);
 559                 return 0;
 560         }
 561
 562         n = startswith(e, "tty");
 563         if (!n)
 564                 return -EINVAL;
 565
 566         r = safe_atou(n, &u);
 567         if (r < 0)
 568                 return r;
 569
 570         if (u <= 0)
 571                 return -EINVAL;
 572
 573         /* Try to deallocate */
 574         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 575         if (fd < 0)
 576                 return fd;
 577
 578         r = ioctl(fd, VT_DISALLOCATE, u);
 579         fd = safe_close(fd);
 580
 581         if (r >= 0)
 582                 return 0;
 583
 584         if (errno != EBUSY)
 585                 return -errno;
 586
 587         /* Couldn't deallocate, so let's clear it fully with
 588          * scrollback */
 589         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 590         if (fd < 0)
 591                 return fd;
 592
 593         loop_write(fd,
 594                    "\033[r"   /* clear scrolling region */
 595                    "\033[H"   /* move home */
 596                    "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
 597                    10, false);
 598         return 0;
 599 }
 600
 601 int make_console_stdio(void) {
 602         int fd, r;
 603
 604         /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
 605
 606         fd = acquire_terminal("/dev/console", ACQUIRE_TERMINAL_FORCE|ACQUIRE_TERMINAL_PERMISSIVE, USEC_INFINITY);
 607         if (fd < 0)
 608                 return log_error_errno(fd, "Failed to acquire terminal: %m");
 609
 610         r = reset_terminal_fd(fd, true);
 611         if (r < 0)
 612                 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
 613
 614         r = rearrange_stdio(fd, fd, fd); /* This invalidates 'fd' both on success and on failure. */
 615         if (r < 0)
 616                 return log_error_errno(r, "Failed to make terminal stdin/stdout/stderr: %m");
 617
 618         reset_terminal_feature_caches();
 619
 620         return 0;
 621 }
 622
 623 bool tty_is_vc(const char *tty) {
 624         assert(tty);
 625
 626         return vtnr_from_tty(tty) >= 0;
 627 }
 628
 629 bool tty_is_console(const char *tty) {
 630         assert(tty);
 631
 632         return streq(skip_dev_prefix(tty), "console");
 633 }
 634
 635 int vtnr_from_tty(const char *tty) {
 636         int i, r;
 637
 638         assert(tty);
 639
 640         tty = skip_dev_prefix(tty);
 641
 642         if (!startswith(tty, "tty") )
 643                 return -EINVAL;
 644
 645         if (tty[3] < '0' || tty[3] > '9')
 646                 return -EINVAL;
 647
 648         r = safe_atoi(tty+3, &i);
 649         if (r < 0)
 650                 return r;
 651
 652         if (i < 0 || i > 63)
 653                 return -EINVAL;
 654
 655         return i;
 656 }
 657
 658  int resolve_dev_console(char **ret) {
 659         _cleanup_free_ char *active = NULL;
 660         char *tty;
 661         int r;
 662
 663         assert(ret);
 664
 665         /* Resolve where /dev/console is pointing to, if /sys is actually ours (i.e. not read-only-mounted which is a
 666          * sign for container setups) */
 667
 668         if (path_is_read_only_fs("/sys") > 0)
 669                 return -ENOMEDIUM;
 670
 671         r = read_one_line_file("/sys/class/tty/console/active", &active);
 672         if (r < 0)
 673                 return r;
 674
 675         /* If multiple log outputs are configured the last one is what /dev/console points to */
 676         tty = strrchr(active, ' ');
 677         if (tty)
 678                 tty++;
 679         else
 680                 tty = active;
 681
 682         if (streq(tty, "tty0")) {
 683                 active = mfree(active);
 684
 685                 /* Get the active VC (e.g. tty1) */
 686                 r = read_one_line_file("/sys/class/tty/tty0/active", &active);
 687                 if (r < 0)
 688                         return r;
 689
 690                 tty = active;
 691         }
 692
 693         if (tty == active)
 694                 *ret = TAKE_PTR(active);
 695         else {
 696                 char *tmp;
 697
 698                 tmp = strdup(tty);
 699                 if (!tmp)
 700                         return -ENOMEM;
 701
 702                 *ret = tmp;
 703         }
 704
 705         return 0;
 706 }
 707
 708 int get_kernel_consoles(char ***ret) {
 709         _cleanup_strv_free_ char **l = NULL;
 710         _cleanup_free_ char *line = NULL;
 711         const char *p;
 712         int r;
 713
 714         assert(ret);
 715
 716         /* If /sys is mounted read-only this means we are running in some kind of container environment. In that
 717          * case /sys would reflect the host system, not us, hence ignore the data we can read from it. */
 718         if (path_is_read_only_fs("/sys") > 0)
 719                 goto fallback;
 720
 721         r = read_one_line_file("/sys/class/tty/console/active", &line);
 722         if (r < 0)
 723                 return r;
 724
 725         p = line;
 726         for (;;) {
 727                 _cleanup_free_ char *tty = NULL;
 728                 char *path;
 729
 730                 r = extract_first_word(&p, &tty, NULL, 0);
 731                 if (r < 0)
 732                         return r;
 733                 if (r == 0)
 734                         break;
 735
 736                 if (streq(tty, "tty0")) {
 737                         tty = mfree(tty);
 738                         r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
 739                         if (r < 0)
 740                                 return r;
 741                 }
 742
 743                 path = strappend("/dev/", tty);
 744                 if (!path)
 745                         return -ENOMEM;
 746
 747                 if (access(path, F_OK) < 0) {
 748                         log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
 749                         free(path);
 750                         continue;
 751                 }
 752
 753                 r = strv_consume(&l, path);
 754                 if (r < 0)
 755                         return r;
 756         }
 757
 758         if (strv_isempty(l)) {
 759                 log_debug("No devices found for system console");
 760                 goto fallback;
 761         }
 762
 763         *ret = TAKE_PTR(l);
 764
 765         return 0;
 766
 767 fallback:
 768         r = strv_extend(&l, "/dev/console");
 769         if (r < 0)
 770                 return r;
 771
 772         *ret = TAKE_PTR(l);
 773
 774         return 0;
 775 }
 776
 777 bool tty_is_vc_resolve(const char *tty) {
 778         _cleanup_free_ char *resolved = NULL;
 779
 780         assert(tty);
 781
 782         tty = skip_dev_prefix(tty);
 783
 784         if (streq(tty, "console")) {
 785                 if (resolve_dev_console(&resolved) < 0)
 786                         return false;
 787
 788                 tty = resolved;
 789         }
 790
 791         return tty_is_vc(tty);
 792 }
 793
 794 const char *default_term_for_tty(const char *tty) {
 795         return tty && tty_is_vc_resolve(tty) ? "linux" : "vt220";
 796 }
 797
 798 int fd_columns(int fd) {
 799         struct winsize ws = {};
 800
 801         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 802                 return -errno;
 803
 804         if (ws.ws_col <= 0)
 805                 return -EIO;
 806
 807         return ws.ws_col;
 808 }
 809
 810 unsigned columns(void) {
 811         const char *e;
 812         int c;
 813
 814         if (cached_columns > 0)
 815                 return cached_columns;
 816
 817         c = 0;
 818         e = getenv("COLUMNS");
 819         if (e)
 820                 (void) safe_atoi(e, &c);
 821
 822         if (c <= 0 || c > USHRT_MAX) {
 823                 c = fd_columns(STDOUT_FILENO);
 824                 if (c <= 0)
 825                         c = 80;
 826         }
 827
 828         cached_columns = c;
 829         return cached_columns;
 830 }
 831
 832 int fd_lines(int fd) {
 833         struct winsize ws = {};
 834
 835         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 836                 return -errno;
 837
 838         if (ws.ws_row <= 0)
 839                 return -EIO;
 840
 841         return ws.ws_row;
 842 }
 843
 844 unsigned lines(void) {
 845         const char *e;
 846         int l;
 847
 848         if (cached_lines > 0)
 849                 return cached_lines;
 850
 851         l = 0;
 852         e = getenv("LINES");
 853         if (e)
 854                 (void) safe_atoi(e, &l);
 855
 856         if (l <= 0 || l > USHRT_MAX) {
 857                 l = fd_lines(STDOUT_FILENO);
 858                 if (l <= 0)
 859                         l = 24;
 860         }
 861
 862         cached_lines = l;
 863         return cached_lines;
 864 }
 865
 866 /* intended to be used as a SIGWINCH sighandler */
 867 void columns_lines_cache_reset(int signum) {
 868         cached_columns = 0;
 869         cached_lines = 0;
 870 }
 871
 872 void reset_terminal_feature_caches(void) {
 873         cached_columns = 0;
 874         cached_lines = 0;
 875
 876         cached_colors_enabled = -1;
 877         cached_underline_enabled = -1;
 878         cached_on_tty = -1;
 879 }
 880
 881 bool on_tty(void) {
 882
 883         /* We check both stdout and stderr, so that situations where pipes on the shell are used are reliably
 884          * recognized, regardless if only the output or the errors are piped to some place. Since on_tty() is generally
 885          * used to default to a safer, non-interactive, non-color mode of operation it's probably good to be defensive
 886          * here, and check for both. Note that we don't check for STDIN_FILENO, because it should fine to use fancy
 887          * terminal functionality when outputting stuff, even if the input is piped to us. */
 888
 889         if (cached_on_tty < 0)
 890                 cached_on_tty =
 891                         isatty(STDOUT_FILENO) > 0 &&
 892                         isatty(STDERR_FILENO) > 0;
 893
 894         return cached_on_tty;
 895 }
 896
 897 int getttyname_malloc(int fd, char **ret) {
 898         size_t l = 100;
 899         int r;
 900
 901         assert(fd >= 0);
 902         assert(ret);
 903
 904         for (;;) {
 905                 char path[l];
 906
 907                 r = ttyname_r(fd, path, sizeof(path));
 908                 if (r == 0) {
 909                         char *c;
 910
 911                         c = strdup(skip_dev_prefix(path));
 912                         if (!c)
 913                                 return -ENOMEM;
 914
 915                         *ret = c;
 916                         return 0;
 917                 }
 918
 919                 if (r != ERANGE)
 920                         return -r;
 921
 922                 l *= 2;
 923         }
 924
 925         return 0;
 926 }
 927
 928 int getttyname_harder(int fd, char **r) {
 929         int k;
 930         char *s = NULL;
 931
 932         k = getttyname_malloc(fd, &s);
 933         if (k < 0)
 934                 return k;
 935
 936         if (streq(s, "tty")) {
 937                 free(s);
 938                 return get_ctty(0, NULL, r);
 939         }
 940
 941         *r = s;
 942         return 0;
 943 }
 944
 945 int get_ctty_devnr(pid_t pid, dev_t *d) {
 946         int r;
 947         _cleanup_free_ char *line = NULL;
 948         const char *p;
 949         unsigned long ttynr;
 950
 951         assert(pid >= 0);
 952
 953         p = procfs_file_alloca(pid, "stat");
 954         r = read_one_line_file(p, &line);
 955         if (r < 0)
 956                 return r;
 957
 958         p = strrchr(line, ')');
 959         if (!p)
 960                 return -EIO;
 961
 962         p++;
 963
 964         if (sscanf(p, " "
 965                    "%*c "  /* state */
 966                    "%*d "  /* ppid */
 967                    "%*d "  /* pgrp */
 968                    "%*d "  /* session */
 969                    "%lu ", /* ttynr */
 970                    &ttynr) != 1)
 971                 return -EIO;
 972
 973         if (major(ttynr) == 0 && minor(ttynr) == 0)
 974                 return -ENXIO;
 975
 976         if (d)
 977                 *d = (dev_t) ttynr;
 978
 979         return 0;
 980 }
 981
 982 int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
 983         char fn[STRLEN("/dev/char/") + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL;
 984         _cleanup_free_ char *s = NULL;
 985         const char *p;
 986         dev_t devnr;
 987         int k;
 988
 989         assert(r);
 990
 991         k = get_ctty_devnr(pid, &devnr);
 992         if (k < 0)
 993                 return k;
 994
 995         sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr));
 996
 997         k = readlink_malloc(fn, &s);
 998         if (k < 0) {
 999
1000                 if (k != -ENOENT)
1001                         return k;
1002
1003                 /* This is an ugly hack */
1004                 if (major(devnr) == 136) {
1005                         if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
1006                                 return -ENOMEM;
1007                 } else {
1008                         /* Probably something like the ptys which have no
1009                          * symlink in /dev/char. Let's return something
1010                          * vaguely useful. */
1011
1012                         b = strdup(fn + 5);
1013                         if (!b)
1014                                 return -ENOMEM;
1015                 }
1016         } else {
1017                 if (startswith(s, "/dev/"))
1018                         p = s + 5;
1019                 else if (startswith(s, "../"))
1020                         p = s + 3;
1021                 else
1022                         p = s;
1023
1024                 b = strdup(p);
1025                 if (!b)
1026                         return -ENOMEM;
1027         }
1028
1029         *r = b;
1030         if (_devnr)
1031                 *_devnr = devnr;
1032
1033         return 0;
1034 }
1035
1036 int ptsname_malloc(int fd, char **ret) {
1037         size_t l = 100;
1038
1039         assert(fd >= 0);
1040         assert(ret);
1041
1042         for (;;) {
1043                 char *c;
1044
1045                 c = new(char, l);
1046                 if (!c)
1047                         return -ENOMEM;
1048
1049                 if (ptsname_r(fd, c, l) == 0) {
1050                         *ret = c;
1051                         return 0;
1052                 }
1053                 if (errno != ERANGE) {
1054                         free(c);
1055                         return -errno;
1056                 }
1057
1058                 free(c);
1059                 l *= 2;
1060         }
1061 }
1062
1063 int ptsname_namespace(int pty, char **ret) {
1064         int no = -1, r;
1065
1066         /* Like ptsname(), but doesn't assume that the path is
1067          * accessible in the local namespace. */
1068
1069         r = ioctl(pty, TIOCGPTN, &no);
1070         if (r < 0)
1071                 return -errno;
1072
1073         if (no < 0)
1074                 return -EIO;
1075
1076         if (asprintf(ret, "/dev/pts/%i", no) < 0)
1077                 return -ENOMEM;
1078
1079         return 0;
1080 }
1081
1082 int openpt_in_namespace(pid_t pid, int flags) {
1083         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1084         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1085         pid_t child;
1086         int r;
1087
1088         assert(pid > 0);
1089
1090         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1091         if (r < 0)
1092                 return r;
1093
1094         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1095                 return -errno;
1096
1097         r = safe_fork("(sd-openpt)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child);
1098         if (r < 0)
1099                 return r;
1100         if (r == 0) {
1101                 int master;
1102
1103                 pair[0] = safe_close(pair[0]);
1104
1105                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1106                 if (r < 0)
1107                         _exit(EXIT_FAILURE);
1108
1109                 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1110                 if (master < 0)
1111                         _exit(EXIT_FAILURE);
1112
1113                 if (unlockpt(master) < 0)
1114                         _exit(EXIT_FAILURE);
1115
1116                 if (send_one_fd(pair[1], master, 0) < 0)
1117                         _exit(EXIT_FAILURE);
1118
1119                 _exit(EXIT_SUCCESS);
1120         }
1121
1122         pair[1] = safe_close(pair[1]);
1123
1124         r = wait_for_terminate_and_check("(sd-openpt)", child, 0);
1125         if (r < 0)
1126                 return r;
1127         if (r != EXIT_SUCCESS)
1128                 return -EIO;
1129
1130         return receive_one_fd(pair[0], 0);
1131 }
1132
1133 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1134         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1135         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1136         pid_t child;
1137         int r;
1138
1139         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1140         if (r < 0)
1141                 return r;
1142
1143         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1144                 return -errno;
1145
1146         r = safe_fork("(sd-terminal)", FORK_RESET_SIGNALS|FORK_DEATHSIG, &child);
1147         if (r < 0)
1148                 return r;
1149         if (r == 0) {
1150                 int master;
1151
1152                 pair[0] = safe_close(pair[0]);
1153
1154                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1155                 if (r < 0)
1156                         _exit(EXIT_FAILURE);
1157
1158                 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1159                 if (master < 0)
1160                         _exit(EXIT_FAILURE);
1161
1162                 if (send_one_fd(pair[1], master, 0) < 0)
1163                         _exit(EXIT_FAILURE);
1164
1165                 _exit(EXIT_SUCCESS);
1166         }
1167
1168         pair[1] = safe_close(pair[1]);
1169
1170         r = wait_for_terminate_and_check("(sd-terminal)", child, 0);
1171         if (r < 0)
1172                 return r;
1173         if (r != EXIT_SUCCESS)
1174                 return -EIO;
1175
1176         return receive_one_fd(pair[0], 0);
1177 }
1178
1179 static bool getenv_terminal_is_dumb(void) {
1180         const char *e;
1181
1182         e = getenv("TERM");
1183         if (!e)
1184                 return true;
1185
1186         return streq(e, "dumb");
1187 }
1188
1189 bool terminal_is_dumb(void) {
1190         if (!on_tty())
1191                 return true;
1192
1193         return getenv_terminal_is_dumb();
1194 }
1195
1196 bool colors_enabled(void) {
1197
1198         /* Returns true if colors are considered supported on our stdout. For that we check $SYSTEMD_COLORS first
1199          * (which is the explicit way to turn colors on/off). If that didn't work we turn colors off unless we are on a
1200          * TTY. And if we are on a TTY we turn it off if $TERM is set to "dumb". There's one special tweak though: if
1201          * we are PID 1 then we do not check whether we are connected to a TTY, because we don't keep /dev/console open
1202          * continously due to fear of SAK, and hence things are a bit weird. */
1203
1204         if (cached_colors_enabled < 0) {
1205                 int val;
1206
1207                 val = getenv_bool("SYSTEMD_COLORS");
1208                 if (val >= 0)
1209                         cached_colors_enabled = val;
1210                 else if (getpid_cached() == 1)
1211                         /* PID1 outputs to the console without holding it open all the time */
1212                         cached_colors_enabled = !getenv_terminal_is_dumb();
1213                 else
1214                         cached_colors_enabled = !terminal_is_dumb();
1215         }
1216
1217         return cached_colors_enabled;
1218 }
1219
1220 bool dev_console_colors_enabled(void) {
1221         _cleanup_free_ char *s = NULL;
1222         int b;
1223
1224         /* Returns true if we assume that color is supported on /dev/console.
1225          *
1226          * For that we first check if we explicitly got told to use colors or not, by checking $SYSTEMD_COLORS. If that
1227          * isn't set we check whether PID 1 has $TERM set, and if not, whether TERM is set on the kernel command
1228          * line. If we find $TERM set we assume color if it's not set to "dumb", similarly to how regular
1229          * colors_enabled() operates. */
1230
1231         b = getenv_bool("SYSTEMD_COLORS");
1232         if (b >= 0)
1233                 return b;
1234
1235         if (getenv_for_pid(1, "TERM", &s) <= 0)
1236                 (void) proc_cmdline_get_key("TERM", 0, &s);
1237
1238         return !streq_ptr(s, "dumb");
1239 }
1240
1241 bool underline_enabled(void) {
1242
1243         if (cached_underline_enabled < 0) {
1244
1245                 /* The Linux console doesn't support underlining, turn it off, but only there. */
1246
1247                 if (colors_enabled())
1248                         cached_underline_enabled = !streq_ptr(getenv("TERM"), "linux");
1249                 else
1250                         cached_underline_enabled = false;
1251         }
1252
1253         return cached_underline_enabled;
1254 }
1255
1256 int vt_default_utf8(void) {
1257         _cleanup_free_ char *b = NULL;
1258         int r;
1259
1260         /* Read the default VT UTF8 setting from the kernel */
1261
1262         r = read_one_line_file("/sys/module/vt/parameters/default_utf8", &b);
1263         if (r < 0)
1264                 return r;
1265
1266         return parse_boolean(b);
1267 }
1268
1269 int vt_reset_keyboard(int fd) {
1270         int kb;
1271
1272         /* If we can't read the default, then default to unicode. It's 2017 after all. */
1273         kb = vt_default_utf8() != 0 ? K_UNICODE : K_XLATE;
1274
1275         if (ioctl(fd, KDSKBMODE, kb) < 0)
1276                 return -errno;
1277
1278         return 0;
1279 }
1280
1281 static bool urlify_enabled(void) {
1282         static int cached_urlify_enabled = -1;
1283
1284         /* Unfortunately 'less' doesn't support links like this yet 😭, hence let's disable this as long as there's a
1285          * pager in effect. Let's drop this check as soon as less got fixed a and enough time passed so that it's safe
1286          * to assume that a link-enabled 'less' version has hit most installations. */
1287
1288         if (cached_urlify_enabled < 0) {
1289                 int val;
1290
1291                 val = getenv_bool("SYSTEMD_URLIFY");
1292                 if (val >= 0)
1293                         cached_urlify_enabled = val;
1294                 else
1295                         cached_urlify_enabled = colors_enabled() && !pager_have();
1296         }
1297
1298         return cached_urlify_enabled;
1299 }
1300
1301 int terminal_urlify(const char *url, const char *text, char **ret) {
1302         char *n;
1303
1304         assert(url);
1305
1306         /* Takes an URL and a pretty string and formats it as clickable link for the terminal. See
1307          * https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda for details. */
1308
1309         if (isempty(text))
1310                 text = url;
1311
1312         if (urlify_enabled())
1313                 n = strjoin("\x1B]8;;", url, "\a", text, "\x1B]8;;\a");
1314         else
1315                 n = strdup(text);
1316         if (!n)
1317                 return -ENOMEM;
1318
1319         *ret = n;
1320         return 0;
1321 }
1322
1323 int terminal_urlify_path(const char *path, const char *text, char **ret) {
1324         _cleanup_free_ char *absolute = NULL;
1325         struct utsname u;
1326         const char *url;
1327         int r;
1328
1329         assert(path);
1330
1331         /* Much like terminal_urlify() above, but takes a file system path as input
1332          * and turns it into a proper file:// URL first. */
1333
1334         if (isempty(path))
1335                 return -EINVAL;
1336
1337         if (isempty(text))
1338                 text = path;
1339
1340         if (!urlify_enabled()) {
1341                 char *n;
1342
1343                 n = strdup(text);
1344                 if (!n)
1345                         return -ENOMEM;
1346
1347                 *ret = n;
1348                 return 0;
1349         }
1350
1351         if (uname(&u) < 0)
1352                 return -errno;
1353
1354         if (!path_is_absolute(path)) {
1355                 r = path_make_absolute_cwd(path, &absolute);
1356                 if (r < 0)
1357                         return r;
1358
1359                 path = absolute;
1360         }
1361
1362         /* As suggested by https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda, let's include the local
1363          * hostname here. Note that we don't use gethostname_malloc() or gethostname_strict() since we are interested
1364          * in the raw string the kernel has set, whatever it may be, under the assumption that terminals are not overly
1365          * careful with validating the strings either. */
1366
1367         url = strjoina("file://", u.nodename, path);
1368
1369         return terminal_urlify(url, text, ret);
1370 }
1371
1372 int terminal_urlify_man(const char *page, const char *section, char **ret) {
1373         const char *url, *text;
1374
1375         url = strjoina("man:", page, "(", section, ")");
1376         text = strjoina(page, "(", section, ") man page");
1377
1378         return terminal_urlify(url, text, ret);
1379 }
1380
1381 static int cat_file(const char *filename, bool newline) {
1382         _cleanup_fclose_ FILE *f = NULL;
1383         _cleanup_free_ char *urlified = NULL;
1384         int r;
1385
1386         f = fopen(filename, "re");
1387         if (!f)
1388                 return -errno;
1389
1390         r = terminal_urlify_path(filename, NULL, &urlified);
1391         if (r < 0)
1392                 return r;
1393
1394         printf("%s%s# %s%s\n",
1395                newline ? "\n" : "",
1396                ansi_highlight_blue(),
1397                urlified,
1398                ansi_normal());
1399         fflush(stdout);
1400
1401         for (;;) {
1402                 _cleanup_free_ char *line = NULL;
1403
1404                 r = read_line(f, LONG_LINE_MAX, &line);
1405                 if (r < 0)
1406                         return log_error_errno(r, "Failed to read \"%s\": %m", filename);
1407                 if (r == 0)
1408                         break;
1409
1410                 puts(line);
1411         }
1412
1413         return 0;
1414 }
1415
1416 int cat_files(const char *file, char **dropins, CatFlags flags) {
1417         char **path;
1418         int r;
1419
1420         if (file) {
1421                 r = cat_file(file, false);
1422                 if (r == -ENOENT && (flags & CAT_FLAGS_MAIN_FILE_OPTIONAL))
1423                         printf("%s# config file %s not found%s\n",
1424                                ansi_highlight_magenta(),
1425                                file,
1426                                ansi_normal());
1427                 else if (r < 0)
1428                         return log_warning_errno(r, "Failed to cat %s: %m", file);
1429         }
1430
1431         STRV_FOREACH(path, dropins) {
1432                 r = cat_file(*path, file || path != dropins);
1433                 if (r < 0)
1434                         return log_warning_errno(r, "Failed to cat %s: %m", *path);
1435         }
1436
1437         return 0;
1438 }
1439
1440 void print_separator(void) {
1441
1442         /* Outputs a separator line that resolves to whitespace when copied from the terminal. We do that by outputting
1443          * one line filled with spaces with ANSI underline set, followed by a second (empty) line. */
1444
1445         if (underline_enabled()) {
1446                 size_t i, c;
1447
1448                 c = columns();
1449
1450                 flockfile(stdout);
1451                 fputs_unlocked(ANSI_UNDERLINE, stdout);
1452
1453                 for (i = 0; i < c; i++)
1454                         fputc_unlocked(' ', stdout);
1455
1456                 fputs_unlocked(ANSI_NORMAL "\n\n", stdout);
1457                 funlockfile(stdout);
1458         } else
1459                 fputs("\n\n", stdout);
1460 }