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