src/basic/terminal-util.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <limits.h>
  23 #include <stdarg.h>
  24 #include <stddef.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <sys/inotify.h>
  28 #include <sys/socket.h>
  29 #include <sys/sysmacros.h>
  30 #include <sys/time.h>
  31 #include <linux/kd.h>
  32 #include <linux/tiocl.h>
  33 #include <linux/vt.h>
  34 #include <poll.h>
  35 #include <signal.h>
  36 #include <sys/ioctl.h>
  37 #include <sys/types.h>
  38 #include <termios.h>
  39 #include <unistd.h>
  40
  41 #include "alloc-util.h"
  42 #include "fd-util.h"
  43 #include "fileio.h"
  44 #include "fs-util.h"
  45 #include "io-util.h"
  46 #include "log.h"
  47 #include "macro.h"
  48 #include "parse-util.h"
  49 #include "process-util.h"
  50 #include "socket-util.h"
  51 #include "stat-util.h"
  52 #include "string-util.h"
  53 #include "strv.h"
  54 #include "terminal-util.h"
  55 #include "time-util.h"
  56 #include "util.h"
  57
  58 static volatile unsigned cached_columns = 0;
  59 static volatile unsigned cached_lines = 0;
  60
  61 int chvt(int vt) {
  62         _cleanup_close_ int fd;
  63
  64         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
  65         if (fd < 0)
  66                 return -errno;
  67
  68         if (vt <= 0) {
  69                 int tiocl[2] = {
  70                         TIOCL_GETKMSGREDIRECT,
  71                         0
  72                 };
  73
  74                 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
  75                         return -errno;
  76
  77                 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
  78         }
  79
  80         if (ioctl(fd, VT_ACTIVATE, vt) < 0)
  81                 return -errno;
  82
  83         return 0;
  84 }
  85
  86 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
  87         struct termios old_termios, new_termios;
  88         char c, line[LINE_MAX];
  89
  90         assert(f);
  91         assert(ret);
  92
  93         if (tcgetattr(fileno(f), &old_termios) >= 0) {
  94                 new_termios = old_termios;
  95
  96                 new_termios.c_lflag &= ~ICANON;
  97                 new_termios.c_cc[VMIN] = 1;
  98                 new_termios.c_cc[VTIME] = 0;
  99
 100                 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
 101                         size_t k;
 102
 103                         if (t != USEC_INFINITY) {
 104                                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
 105                                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 106                                         return -ETIMEDOUT;
 107                                 }
 108                         }
 109
 110                         k = fread(&c, 1, 1, f);
 111
 112                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 113
 114                         if (k <= 0)
 115                                 return -EIO;
 116
 117                         if (need_nl)
 118                                 *need_nl = c != '\n';
 119
 120                         *ret = c;
 121                         return 0;
 122                 }
 123         }
 124
 125         if (t != USEC_INFINITY) {
 126                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
 127                         return -ETIMEDOUT;
 128         }
 129
 130         errno = 0;
 131         if (!fgets(line, sizeof(line), f))
 132                 return errno > 0 ? -errno : -EIO;
 133
 134         truncate_nl(line);
 135
 136         if (strlen(line) != 1)
 137                 return -EBADMSG;
 138
 139         if (need_nl)
 140                 *need_nl = false;
 141
 142         *ret = line[0];
 143         return 0;
 144 }
 145
 146 int ask_char(char *ret, const char *replies, const char *text, ...) {
 147         int r;
 148
 149         assert(ret);
 150         assert(replies);
 151         assert(text);
 152
 153         for (;;) {
 154                 va_list ap;
 155                 char c;
 156                 bool need_nl = true;
 157
 158                 if (colors_enabled())
 159                         fputs(ANSI_HIGHLIGHT, stdout);
 160
 161                 va_start(ap, text);
 162                 vprintf(text, ap);
 163                 va_end(ap);
 164
 165                 if (colors_enabled())
 166                         fputs(ANSI_NORMAL, stdout);
 167
 168                 fflush(stdout);
 169
 170                 r = read_one_char(stdin, &c, USEC_INFINITY, &need_nl);
 171                 if (r < 0) {
 172
 173                         if (r == -EBADMSG) {
 174                                 puts("Bad input, please try again.");
 175                                 continue;
 176                         }
 177
 178                         putchar('\n');
 179                         return r;
 180                 }
 181
 182                 if (need_nl)
 183                         putchar('\n');
 184
 185                 if (strchr(replies, c)) {
 186                         *ret = c;
 187                         return 0;
 188                 }
 189
 190                 puts("Read unexpected character, please try again.");
 191         }
 192 }
 193
 194 int ask_string(char **ret, const char *text, ...) {
 195         assert(ret);
 196         assert(text);
 197
 198         for (;;) {
 199                 char line[LINE_MAX];
 200                 va_list ap;
 201
 202                 if (colors_enabled())
 203                         fputs(ANSI_HIGHLIGHT, stdout);
 204
 205                 va_start(ap, text);
 206                 vprintf(text, ap);
 207                 va_end(ap);
 208
 209                 if (colors_enabled())
 210                         fputs(ANSI_NORMAL, stdout);
 211
 212                 fflush(stdout);
 213
 214                 errno = 0;
 215                 if (!fgets(line, sizeof(line), stdin))
 216                         return errno > 0 ? -errno : -EIO;
 217
 218                 if (!endswith(line, "\n"))
 219                         putchar('\n');
 220                 else {
 221                         char *s;
 222
 223                         if (isempty(line))
 224                                 continue;
 225
 226                         truncate_nl(line);
 227                         s = strdup(line);
 228                         if (!s)
 229                                 return -ENOMEM;
 230
 231                         *ret = s;
 232                         return 0;
 233                 }
 234         }
 235 }
 236
 237 int reset_terminal_fd(int fd, bool switch_to_text) {
 238         struct termios termios;
 239         int r = 0;
 240
 241         /* Set terminal to some sane defaults */
 242
 243         assert(fd >= 0);
 244
 245         /* We leave locked terminal attributes untouched, so that
 246          * Plymouth may set whatever it wants to set, and we don't
 247          * interfere with that. */
 248
 249         /* Disable exclusive mode, just in case */
 250         (void) ioctl(fd, TIOCNXCL);
 251
 252         /* Switch to text mode */
 253         if (switch_to_text)
 254                 (void) ioctl(fd, KDSETMODE, KD_TEXT);
 255
 256         /* Enable console unicode mode */
 257         (void) ioctl(fd, KDSKBMODE, K_UNICODE);
 258
 259         if (tcgetattr(fd, &termios) < 0) {
 260                 r = -errno;
 261                 goto finish;
 262         }
 263
 264         /* We only reset the stuff that matters to the software. How
 265          * hardware is set up we don't touch assuming that somebody
 266          * else will do that for us */
 267
 268         termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
 269         termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
 270         termios.c_oflag |= ONLCR;
 271         termios.c_cflag |= CREAD;
 272         termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
 273
 274         termios.c_cc[VINTR]    =   03;  /* ^C */
 275         termios.c_cc[VQUIT]    =  034;  /* ^\ */
 276         termios.c_cc[VERASE]   = 0177;
 277         termios.c_cc[VKILL]    =  025;  /* ^X */
 278         termios.c_cc[VEOF]     =   04;  /* ^D */
 279         termios.c_cc[VSTART]   =  021;  /* ^Q */
 280         termios.c_cc[VSTOP]    =  023;  /* ^S */
 281         termios.c_cc[VSUSP]    =  032;  /* ^Z */
 282         termios.c_cc[VLNEXT]   =  026;  /* ^V */
 283         termios.c_cc[VWERASE]  =  027;  /* ^W */
 284         termios.c_cc[VREPRINT] =  022;  /* ^R */
 285         termios.c_cc[VEOL]     =    0;
 286         termios.c_cc[VEOL2]    =    0;
 287
 288         termios.c_cc[VTIME]  = 0;
 289         termios.c_cc[VMIN]   = 1;
 290
 291         if (tcsetattr(fd, TCSANOW, &termios) < 0)
 292                 r = -errno;
 293
 294 finish:
 295         /* Just in case, flush all crap out */
 296         (void) tcflush(fd, TCIOFLUSH);
 297
 298         return r;
 299 }
 300
 301 int reset_terminal(const char *name) {
 302         _cleanup_close_ int fd = -1;
 303
 304         /* We open the terminal with O_NONBLOCK here, to ensure we
 305          * don't block on carrier if this is a terminal with carrier
 306          * configured. */
 307
 308         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 309         if (fd < 0)
 310                 return fd;
 311
 312         return reset_terminal_fd(fd, true);
 313 }
 314
 315 int open_terminal(const char *name, int mode) {
 316         int fd, r;
 317         unsigned c = 0;
 318
 319         /*
 320          * If a TTY is in the process of being closed opening it might
 321          * cause EIO. This is horribly awful, but unlikely to be
 322          * changed in the kernel. Hence we work around this problem by
 323          * retrying a couple of 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                 usleep(50 * USEC_PER_MSEC);
 344                 c++;
 345         }
 346
 347         r = isatty(fd);
 348         if (r < 0) {
 349                 safe_close(fd);
 350                 return -errno;
 351         }
 352
 353         if (!r) {
 354                 safe_close(fd);
 355                 return -ENOTTY;
 356         }
 357
 358         return fd;
 359 }
 360
 361 int acquire_terminal(
 362                 const char *name,
 363                 bool fail,
 364                 bool force,
 365                 bool ignore_tiocstty_eperm,
 366                 usec_t timeout) {
 367
 368         int fd = -1, notify = -1, r = 0, wd = -1;
 369         usec_t ts = 0;
 370
 371         assert(name);
 372
 373         /* We use inotify to be notified when the tty is closed. We
 374          * create the watch before checking if we can actually acquire
 375          * it, so that we don't lose any event.
 376          *
 377          * Note: strictly speaking this actually watches for the
 378          * device being closed, it does *not* really watch whether a
 379          * tty loses its controlling process. However, unless some
 380          * rogue process uses TIOCNOTTY on /dev/tty *after* closing
 381          * its tty otherwise this will not become a problem. As long
 382          * as the administrator makes sure not configure any service
 383          * on the same tty as an untrusted user this should not be a
 384          * problem. (Which he probably should not do anyway.) */
 385
 386         if (timeout != USEC_INFINITY)
 387                 ts = now(CLOCK_MONOTONIC);
 388
 389         if (!fail && !force) {
 390                 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
 391                 if (notify < 0) {
 392                         r = -errno;
 393                         goto fail;
 394                 }
 395
 396                 wd = inotify_add_watch(notify, name, IN_CLOSE);
 397                 if (wd < 0) {
 398                         r = -errno;
 399                         goto fail;
 400                 }
 401         }
 402
 403         for (;;) {
 404                 struct sigaction sa_old, sa_new = {
 405                         .sa_handler = SIG_IGN,
 406                         .sa_flags = SA_RESTART,
 407                 };
 408
 409                 if (notify >= 0) {
 410                         r = flush_fd(notify);
 411                         if (r < 0)
 412                                 goto fail;
 413                 }
 414
 415                 /* We pass here O_NOCTTY only so that we can check the return
 416                  * value TIOCSCTTY and have a reliable way to figure out if we
 417                  * successfully became the controlling process of the tty */
 418                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 419                 if (fd < 0)
 420                         return fd;
 421
 422                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 423                  * if we already own the tty. */
 424                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 425
 426                 /* First, try to get the tty */
 427                 if (ioctl(fd, TIOCSCTTY, force) < 0)
 428                         r = -errno;
 429
 430                 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 431
 432                 /* Sometimes, it makes sense to ignore TIOCSCTTY
 433                  * returning EPERM, i.e. when very likely we already
 434                  * are have this controlling terminal. */
 435                 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
 436                         r = 0;
 437
 438                 if (r < 0 && (force || fail || r != -EPERM))
 439                         goto fail;
 440
 441                 if (r >= 0)
 442                         break;
 443
 444                 assert(!fail);
 445                 assert(!force);
 446                 assert(notify >= 0);
 447
 448                 for (;;) {
 449                         union inotify_event_buffer buffer;
 450                         struct inotify_event *e;
 451                         ssize_t l;
 452
 453                         if (timeout != USEC_INFINITY) {
 454                                 usec_t n;
 455
 456                                 n = now(CLOCK_MONOTONIC);
 457                                 if (ts + timeout < n) {
 458                                         r = -ETIMEDOUT;
 459                                         goto fail;
 460                                 }
 461
 462                                 r = fd_wait_for_event(fd, POLLIN, ts + timeout - n);
 463                                 if (r < 0)
 464                                         goto fail;
 465
 466                                 if (r == 0) {
 467                                         r = -ETIMEDOUT;
 468                                         goto fail;
 469                                 }
 470                         }
 471
 472                         l = read(notify, &buffer, sizeof(buffer));
 473                         if (l < 0) {
 474                                 if (errno == EINTR || errno == EAGAIN)
 475                                         continue;
 476
 477                                 r = -errno;
 478                                 goto fail;
 479                         }
 480
 481                         FOREACH_INOTIFY_EVENT(e, buffer, l) {
 482                                 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
 483                                         r = -EIO;
 484                                         goto fail;
 485                                 }
 486                         }
 487
 488                         break;
 489                 }
 490
 491                 /* We close the tty fd here since if the old session
 492                  * ended our handle will be dead. It's important that
 493                  * we do this after sleeping, so that we don't enter
 494                  * an endless loop. */
 495                 fd = safe_close(fd);
 496         }
 497
 498         safe_close(notify);
 499
 500         return fd;
 501
 502 fail:
 503         safe_close(fd);
 504         safe_close(notify);
 505
 506         return r;
 507 }
 508
 509 int release_terminal(void) {
 510         static const struct sigaction sa_new = {
 511                 .sa_handler = SIG_IGN,
 512                 .sa_flags = SA_RESTART,
 513         };
 514
 515         _cleanup_close_ int fd = -1;
 516         struct sigaction sa_old;
 517         int r = 0;
 518
 519         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 520         if (fd < 0)
 521                 return -errno;
 522
 523         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 524          * by our own TIOCNOTTY */
 525         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 526
 527         if (ioctl(fd, TIOCNOTTY) < 0)
 528                 r = -errno;
 529
 530         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 531
 532         return r;
 533 }
 534
 535 int terminal_vhangup_fd(int fd) {
 536         assert(fd >= 0);
 537
 538         if (ioctl(fd, TIOCVHANGUP) < 0)
 539                 return -errno;
 540
 541         return 0;
 542 }
 543
 544 int terminal_vhangup(const char *name) {
 545         _cleanup_close_ int fd;
 546
 547         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 548         if (fd < 0)
 549                 return fd;
 550
 551         return terminal_vhangup_fd(fd);
 552 }
 553
 554 int vt_disallocate(const char *name) {
 555         _cleanup_close_ int fd = -1;
 556         unsigned u;
 557         int r;
 558
 559         /* Deallocate the VT if possible. If not possible
 560          * (i.e. because it is the active one), at least clear it
 561          * entirely (including the scrollback buffer) */
 562
 563         if (!startswith(name, "/dev/"))
 564                 return -EINVAL;
 565
 566         if (!tty_is_vc(name)) {
 567                 /* So this is not a VT. I guess we cannot deallocate
 568                  * it then. But let's at least clear the screen */
 569
 570                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 571                 if (fd < 0)
 572                         return fd;
 573
 574                 loop_write(fd,
 575                            "\033[r"    /* clear scrolling region */
 576                            "\033[H"    /* move home */
 577                            "\033[2J",  /* clear screen */
 578                            10, false);
 579                 return 0;
 580         }
 581
 582         if (!startswith(name, "/dev/tty"))
 583                 return -EINVAL;
 584
 585         r = safe_atou(name+8, &u);
 586         if (r < 0)
 587                 return r;
 588
 589         if (u <= 0)
 590                 return -EINVAL;
 591
 592         /* Try to deallocate */
 593         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 594         if (fd < 0)
 595                 return fd;
 596
 597         r = ioctl(fd, VT_DISALLOCATE, u);
 598         fd = safe_close(fd);
 599
 600         if (r >= 0)
 601                 return 0;
 602
 603         if (errno != EBUSY)
 604                 return -errno;
 605
 606         /* Couldn't deallocate, so let's clear it fully with
 607          * scrollback */
 608         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 609         if (fd < 0)
 610                 return fd;
 611
 612         loop_write(fd,
 613                    "\033[r"   /* clear scrolling region */
 614                    "\033[H"   /* move home */
 615                    "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
 616                    10, false);
 617         return 0;
 618 }
 619
 620 int make_console_stdio(void) {
 621         int fd, r;
 622
 623         /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
 624
 625         fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
 626         if (fd < 0)
 627                 return log_error_errno(fd, "Failed to acquire terminal: %m");
 628
 629         r = reset_terminal_fd(fd, true);
 630         if (r < 0)
 631                 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
 632
 633         r = make_stdio(fd);
 634         if (r < 0)
 635                 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
 636
 637         return 0;
 638 }
 639
 640 bool tty_is_vc(const char *tty) {
 641         assert(tty);
 642
 643         return vtnr_from_tty(tty) >= 0;
 644 }
 645
 646 bool tty_is_console(const char *tty) {
 647         assert(tty);
 648
 649         if (startswith(tty, "/dev/"))
 650                 tty += 5;
 651
 652         return streq(tty, "console");
 653 }
 654
 655 int vtnr_from_tty(const char *tty) {
 656         int i, r;
 657
 658         assert(tty);
 659
 660         if (startswith(tty, "/dev/"))
 661                 tty += 5;
 662
 663         if (!startswith(tty, "tty") )
 664                 return -EINVAL;
 665
 666         if (tty[3] < '0' || tty[3] > '9')
 667                 return -EINVAL;
 668
 669         r = safe_atoi(tty+3, &i);
 670         if (r < 0)
 671                 return r;
 672
 673         if (i < 0 || i > 63)
 674                 return -EINVAL;
 675
 676         return i;
 677 }
 678
 679 char *resolve_dev_console(char **active) {
 680         char *tty;
 681
 682         /* Resolve where /dev/console is pointing to, if /sys is actually ours
 683          * (i.e. not read-only-mounted which is a sign for container setups) */
 684
 685         if (path_is_read_only_fs("/sys") > 0)
 686                 return NULL;
 687
 688         if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
 689                 return NULL;
 690
 691         /* If multiple log outputs are configured the last one is what
 692          * /dev/console points to */
 693         tty = strrchr(*active, ' ');
 694         if (tty)
 695                 tty++;
 696         else
 697                 tty = *active;
 698
 699         if (streq(tty, "tty0")) {
 700                 char *tmp;
 701
 702                 /* Get the active VC (e.g. tty1) */
 703                 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
 704                         free(*active);
 705                         tty = *active = tmp;
 706                 }
 707         }
 708
 709         return tty;
 710 }
 711
 712 int get_kernel_consoles(char ***consoles) {
 713         _cleanup_strv_free_ char **con = NULL;
 714         _cleanup_free_ char *line = NULL;
 715         const char *active;
 716         int r;
 717
 718         assert(consoles);
 719
 720         r = read_one_line_file("/sys/class/tty/console/active", &line);
 721         if (r < 0)
 722                 return r;
 723
 724         active = line;
 725         for (;;) {
 726                 _cleanup_free_ char *tty = NULL;
 727                 char *path;
 728
 729                 r = extract_first_word(&active, &tty, NULL, 0);
 730                 if (r < 0)
 731                         return r;
 732                 if (r == 0)
 733                         break;
 734
 735                 if (streq(tty, "tty0")) {
 736                         tty = mfree(tty);
 737                         r = read_one_line_file("/sys/class/tty/tty0/active", &tty);
 738                         if (r < 0)
 739                                 return r;
 740                 }
 741
 742                 path = strappend("/dev/", tty);
 743                 if (!path)
 744                         return -ENOMEM;
 745
 746                 if (access(path, F_OK) < 0) {
 747                         log_debug_errno(errno, "Console device %s is not accessible, skipping: %m", path);
 748                         free(path);
 749                         continue;
 750                 }
 751
 752                 r = strv_consume(&con, path);
 753                 if (r < 0)
 754                         return r;
 755         }
 756
 757         if (strv_isempty(con)) {
 758                 log_debug("No devices found for system console");
 759
 760                 r = strv_extend(&con, "/dev/console");
 761                 if (r < 0)
 762                         return r;
 763         }
 764
 765         *consoles = con;
 766         con = NULL;
 767         return 0;
 768 }
 769
 770 bool tty_is_vc_resolve(const char *tty) {
 771         _cleanup_free_ char *active = NULL;
 772
 773         assert(tty);
 774
 775         if (startswith(tty, "/dev/"))
 776                 tty += 5;
 777
 778         if (streq(tty, "console")) {
 779                 tty = resolve_dev_console(&active);
 780                 if (!tty)
 781                         return false;
 782         }
 783
 784         return tty_is_vc(tty);
 785 }
 786
 787 const char *default_term_for_tty(const char *tty) {
 788         return tty && tty_is_vc_resolve(tty) ? "TERM=linux" : "TERM=vt220";
 789 }
 790
 791 int fd_columns(int fd) {
 792         struct winsize ws = {};
 793
 794         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 795                 return -errno;
 796
 797         if (ws.ws_col <= 0)
 798                 return -EIO;
 799
 800         return ws.ws_col;
 801 }
 802
 803 unsigned columns(void) {
 804         const char *e;
 805         int c;
 806
 807         if (_likely_(cached_columns > 0))
 808                 return cached_columns;
 809
 810         c = 0;
 811         e = getenv("COLUMNS");
 812         if (e)
 813                 (void) safe_atoi(e, &c);
 814
 815         if (c <= 0)
 816                 c = fd_columns(STDOUT_FILENO);
 817
 818         if (c <= 0)
 819                 c = 80;
 820
 821         cached_columns = c;
 822         return cached_columns;
 823 }
 824
 825 int fd_lines(int fd) {
 826         struct winsize ws = {};
 827
 828         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 829                 return -errno;
 830
 831         if (ws.ws_row <= 0)
 832                 return -EIO;
 833
 834         return ws.ws_row;
 835 }
 836
 837 unsigned lines(void) {
 838         const char *e;
 839         int l;
 840
 841         if (_likely_(cached_lines > 0))
 842                 return cached_lines;
 843
 844         l = 0;
 845         e = getenv("LINES");
 846         if (e)
 847                 (void) safe_atoi(e, &l);
 848
 849         if (l <= 0)
 850                 l = fd_lines(STDOUT_FILENO);
 851
 852         if (l <= 0)
 853                 l = 24;
 854
 855         cached_lines = l;
 856         return cached_lines;
 857 }
 858
 859 /* intended to be used as a SIGWINCH sighandler */
 860 void columns_lines_cache_reset(int signum) {
 861         cached_columns = 0;
 862         cached_lines = 0;
 863 }
 864
 865 bool on_tty(void) {
 866         static int cached_on_tty = -1;
 867
 868         if (_unlikely_(cached_on_tty < 0))
 869                 cached_on_tty = isatty(STDOUT_FILENO) > 0;
 870
 871         return cached_on_tty;
 872 }
 873
 874 int make_stdio(int fd) {
 875         int r, s, t;
 876
 877         assert(fd >= 0);
 878
 879         r = dup2(fd, STDIN_FILENO);
 880         s = dup2(fd, STDOUT_FILENO);
 881         t = dup2(fd, STDERR_FILENO);
 882
 883         if (fd >= 3)
 884                 safe_close(fd);
 885
 886         if (r < 0 || s < 0 || t < 0)
 887                 return -errno;
 888
 889         /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
 890          * dup2() was a NOP and the bit hence possibly set. */
 891         fd_cloexec(STDIN_FILENO, false);
 892         fd_cloexec(STDOUT_FILENO, false);
 893         fd_cloexec(STDERR_FILENO, false);
 894
 895         return 0;
 896 }
 897
 898 int make_null_stdio(void) {
 899         int null_fd;
 900
 901         null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
 902         if (null_fd < 0)
 903                 return -errno;
 904
 905         return make_stdio(null_fd);
 906 }
 907
 908 int getttyname_malloc(int fd, char **ret) {
 909         size_t l = 100;
 910         int r;
 911
 912         assert(fd >= 0);
 913         assert(ret);
 914
 915         for (;;) {
 916                 char path[l];
 917
 918                 r = ttyname_r(fd, path, sizeof(path));
 919                 if (r == 0) {
 920                         const char *p;
 921                         char *c;
 922
 923                         p = startswith(path, "/dev/");
 924                         c = strdup(p ?: path);
 925                         if (!c)
 926                                 return -ENOMEM;
 927
 928                         *ret = c;
 929                         return 0;
 930                 }
 931
 932                 if (r != ERANGE)
 933                         return -r;
 934
 935                 l *= 2;
 936         }
 937
 938         return 0;
 939 }
 940
 941 int getttyname_harder(int fd, char **r) {
 942         int k;
 943         char *s = NULL;
 944
 945         k = getttyname_malloc(fd, &s);
 946         if (k < 0)
 947                 return k;
 948
 949         if (streq(s, "tty")) {
 950                 free(s);
 951                 return get_ctty(0, NULL, r);
 952         }
 953
 954         *r = s;
 955         return 0;
 956 }
 957
 958 int get_ctty_devnr(pid_t pid, dev_t *d) {
 959         int r;
 960         _cleanup_free_ char *line = NULL;
 961         const char *p;
 962         unsigned long ttynr;
 963
 964         assert(pid >= 0);
 965
 966         p = procfs_file_alloca(pid, "stat");
 967         r = read_one_line_file(p, &line);
 968         if (r < 0)
 969                 return r;
 970
 971         p = strrchr(line, ')');
 972         if (!p)
 973                 return -EIO;
 974
 975         p++;
 976
 977         if (sscanf(p, " "
 978                    "%*c "  /* state */
 979                    "%*d "  /* ppid */
 980                    "%*d "  /* pgrp */
 981                    "%*d "  /* session */
 982                    "%lu ", /* ttynr */
 983                    &ttynr) != 1)
 984                 return -EIO;
 985
 986         if (major(ttynr) == 0 && minor(ttynr) == 0)
 987                 return -ENXIO;
 988
 989         if (d)
 990                 *d = (dev_t) ttynr;
 991
 992         return 0;
 993 }
 994
 995 int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
 996         char fn[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL;
 997         _cleanup_free_ char *s = NULL;
 998         const char *p;
 999         dev_t devnr;
1000         int k;
1001
1002         assert(r);
1003
1004         k = get_ctty_devnr(pid, &devnr);
1005         if (k < 0)
1006                 return k;
1007
1008         sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr));
1009
1010         k = readlink_malloc(fn, &s);
1011         if (k < 0) {
1012
1013                 if (k != -ENOENT)
1014                         return k;
1015
1016                 /* This is an ugly hack */
1017                 if (major(devnr) == 136) {
1018                         if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
1019                                 return -ENOMEM;
1020                 } else {
1021                         /* Probably something like the ptys which have no
1022                          * symlink in /dev/char. Let's return something
1023                          * vaguely useful. */
1024
1025                         b = strdup(fn + 5);
1026                         if (!b)
1027                                 return -ENOMEM;
1028                 }
1029         } else {
1030                 if (startswith(s, "/dev/"))
1031                         p = s + 5;
1032                 else if (startswith(s, "../"))
1033                         p = s + 3;
1034                 else
1035                         p = s;
1036
1037                 b = strdup(p);
1038                 if (!b)
1039                         return -ENOMEM;
1040         }
1041
1042         *r = b;
1043         if (_devnr)
1044                 *_devnr = devnr;
1045
1046         return 0;
1047 }
1048
1049 int ptsname_malloc(int fd, char **ret) {
1050         size_t l = 100;
1051
1052         assert(fd >= 0);
1053         assert(ret);
1054
1055         for (;;) {
1056                 char *c;
1057
1058                 c = new(char, l);
1059                 if (!c)
1060                         return -ENOMEM;
1061
1062                 if (ptsname_r(fd, c, l) == 0) {
1063                         *ret = c;
1064                         return 0;
1065                 }
1066                 if (errno != ERANGE) {
1067                         free(c);
1068                         return -errno;
1069                 }
1070
1071                 free(c);
1072                 l *= 2;
1073         }
1074 }
1075
1076 int ptsname_namespace(int pty, char **ret) {
1077         int no = -1, r;
1078
1079         /* Like ptsname(), but doesn't assume that the path is
1080          * accessible in the local namespace. */
1081
1082         r = ioctl(pty, TIOCGPTN, &no);
1083         if (r < 0)
1084                 return -errno;
1085
1086         if (no < 0)
1087                 return -EIO;
1088
1089         if (asprintf(ret, "/dev/pts/%i", no) < 0)
1090                 return -ENOMEM;
1091
1092         return 0;
1093 }
1094
1095 int openpt_in_namespace(pid_t pid, int flags) {
1096         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1097         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1098         siginfo_t si;
1099         pid_t child;
1100         int r;
1101
1102         assert(pid > 0);
1103
1104         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1105         if (r < 0)
1106                 return r;
1107
1108         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1109                 return -errno;
1110
1111         child = fork();
1112         if (child < 0)
1113                 return -errno;
1114
1115         if (child == 0) {
1116                 int master;
1117
1118                 pair[0] = safe_close(pair[0]);
1119
1120                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1121                 if (r < 0)
1122                         _exit(EXIT_FAILURE);
1123
1124                 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1125                 if (master < 0)
1126                         _exit(EXIT_FAILURE);
1127
1128                 if (unlockpt(master) < 0)
1129                         _exit(EXIT_FAILURE);
1130
1131                 if (send_one_fd(pair[1], master, 0) < 0)
1132                         _exit(EXIT_FAILURE);
1133
1134                 _exit(EXIT_SUCCESS);
1135         }
1136
1137         pair[1] = safe_close(pair[1]);
1138
1139         r = wait_for_terminate(child, &si);
1140         if (r < 0)
1141                 return r;
1142         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1143                 return -EIO;
1144
1145         return receive_one_fd(pair[0], 0);
1146 }
1147
1148 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1149         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1150         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1151         siginfo_t si;
1152         pid_t child;
1153         int r;
1154
1155         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1156         if (r < 0)
1157                 return r;
1158
1159         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1160                 return -errno;
1161
1162         child = fork();
1163         if (child < 0)
1164                 return -errno;
1165
1166         if (child == 0) {
1167                 int master;
1168
1169                 pair[0] = safe_close(pair[0]);
1170
1171                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1172                 if (r < 0)
1173                         _exit(EXIT_FAILURE);
1174
1175                 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1176                 if (master < 0)
1177                         _exit(EXIT_FAILURE);
1178
1179                 if (send_one_fd(pair[1], master, 0) < 0)
1180                         _exit(EXIT_FAILURE);
1181
1182                 _exit(EXIT_SUCCESS);
1183         }
1184
1185         pair[1] = safe_close(pair[1]);
1186
1187         r = wait_for_terminate(child, &si);
1188         if (r < 0)
1189                 return r;
1190         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1191                 return -EIO;
1192
1193         return receive_one_fd(pair[0], 0);
1194 }
1195
1196 bool colors_enabled(void) {
1197         static int enabled = -1;
1198
1199         if (_unlikely_(enabled < 0)) {
1200                 const char *colors;
1201
1202                 colors = getenv("SYSTEMD_COLORS");
1203                 if (colors)
1204                         enabled = parse_boolean(colors) != 0;
1205                 else if (streq_ptr(getenv("TERM"), "dumb"))
1206                         enabled = false;
1207                 else
1208                         enabled = on_tty();
1209         }
1210
1211         return enabled;
1212 }