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 <assert.h>
  21 #include <fcntl.h>
  22 #include <linux/kd.h>
  23 #include <linux/tiocl.h>
  24 #include <linux/vt.h>
  25 #include <poll.h>
  26 #include <signal.h>
  27 #include <sys/ioctl.h>
  28 #include <sys/stat.h>
  29 #include <sys/types.h>
  30 #include <termios.h>
  31 #include <time.h>
  32 #include <unistd.h>
  33
  34 #include "fd-util.h"
  35 #include "fileio.h"
  36 #include "io-util.h"
  37 #include "path-util.h"
  38 #include "process-util.h"
  39 #include "socket-util.h"
  40 #include "string-util.h"
  41 #include "terminal-util.h"
  42 #include "time-util.h"
  43 #include "util.h"
  44
  45 static volatile unsigned cached_columns = 0;
  46 static volatile unsigned cached_lines = 0;
  47
  48 int chvt(int vt) {
  49         _cleanup_close_ int fd;
  50
  51         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
  52         if (fd < 0)
  53                 return -errno;
  54
  55         if (vt <= 0) {
  56                 int tiocl[2] = {
  57                         TIOCL_GETKMSGREDIRECT,
  58                         0
  59                 };
  60
  61                 if (ioctl(fd, TIOCLINUX, tiocl) < 0)
  62                         return -errno;
  63
  64                 vt = tiocl[0] <= 0 ? 1 : tiocl[0];
  65         }
  66
  67         if (ioctl(fd, VT_ACTIVATE, vt) < 0)
  68                 return -errno;
  69
  70         return 0;
  71 }
  72
  73 int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
  74         struct termios old_termios, new_termios;
  75         char c, line[LINE_MAX];
  76
  77         assert(f);
  78         assert(ret);
  79
  80         if (tcgetattr(fileno(f), &old_termios) >= 0) {
  81                 new_termios = old_termios;
  82
  83                 new_termios.c_lflag &= ~ICANON;
  84                 new_termios.c_cc[VMIN] = 1;
  85                 new_termios.c_cc[VTIME] = 0;
  86
  87                 if (tcsetattr(fileno(f), TCSADRAIN, &new_termios) >= 0) {
  88                         size_t k;
  89
  90                         if (t != USEC_INFINITY) {
  91                                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0) {
  92                                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
  93                                         return -ETIMEDOUT;
  94                                 }
  95                         }
  96
  97                         k = fread(&c, 1, 1, f);
  98
  99                         tcsetattr(fileno(f), TCSADRAIN, &old_termios);
 100
 101                         if (k <= 0)
 102                                 return -EIO;
 103
 104                         if (need_nl)
 105                                 *need_nl = c != '\n';
 106
 107                         *ret = c;
 108                         return 0;
 109                 }
 110         }
 111
 112         if (t != USEC_INFINITY) {
 113                 if (fd_wait_for_event(fileno(f), POLLIN, t) <= 0)
 114                         return -ETIMEDOUT;
 115         }
 116
 117         errno = 0;
 118         if (!fgets(line, sizeof(line), f))
 119                 return errno ? -errno : -EIO;
 120
 121         truncate_nl(line);
 122
 123         if (strlen(line) != 1)
 124                 return -EBADMSG;
 125
 126         if (need_nl)
 127                 *need_nl = false;
 128
 129         *ret = line[0];
 130         return 0;
 131 }
 132
 133 int ask_char(char *ret, const char *replies, const char *text, ...) {
 134         int r;
 135
 136         assert(ret);
 137         assert(replies);
 138         assert(text);
 139
 140         for (;;) {
 141                 va_list ap;
 142                 char c;
 143                 bool need_nl = true;
 144
 145                 if (on_tty())
 146                         fputs(ANSI_HIGHLIGHT, stdout);
 147
 148                 va_start(ap, text);
 149                 vprintf(text, ap);
 150                 va_end(ap);
 151
 152                 if (on_tty())
 153                         fputs(ANSI_NORMAL, stdout);
 154
 155                 fflush(stdout);
 156
 157                 r = read_one_char(stdin, &c, USEC_INFINITY, &need_nl);
 158                 if (r < 0) {
 159
 160                         if (r == -EBADMSG) {
 161                                 puts("Bad input, please try again.");
 162                                 continue;
 163                         }
 164
 165                         putchar('\n');
 166                         return r;
 167                 }
 168
 169                 if (need_nl)
 170                         putchar('\n');
 171
 172                 if (strchr(replies, c)) {
 173                         *ret = c;
 174                         return 0;
 175                 }
 176
 177                 puts("Read unexpected character, please try again.");
 178         }
 179 }
 180
 181 int ask_string(char **ret, const char *text, ...) {
 182         assert(ret);
 183         assert(text);
 184
 185         for (;;) {
 186                 char line[LINE_MAX];
 187                 va_list ap;
 188
 189                 if (on_tty())
 190                         fputs(ANSI_HIGHLIGHT, stdout);
 191
 192                 va_start(ap, text);
 193                 vprintf(text, ap);
 194                 va_end(ap);
 195
 196                 if (on_tty())
 197                         fputs(ANSI_NORMAL, stdout);
 198
 199                 fflush(stdout);
 200
 201                 errno = 0;
 202                 if (!fgets(line, sizeof(line), stdin))
 203                         return errno ? -errno : -EIO;
 204
 205                 if (!endswith(line, "\n"))
 206                         putchar('\n');
 207                 else {
 208                         char *s;
 209
 210                         if (isempty(line))
 211                                 continue;
 212
 213                         truncate_nl(line);
 214                         s = strdup(line);
 215                         if (!s)
 216                                 return -ENOMEM;
 217
 218                         *ret = s;
 219                         return 0;
 220                 }
 221         }
 222 }
 223
 224 int reset_terminal_fd(int fd, bool switch_to_text) {
 225         struct termios termios;
 226         int r = 0;
 227
 228         /* Set terminal to some sane defaults */
 229
 230         assert(fd >= 0);
 231
 232         /* We leave locked terminal attributes untouched, so that
 233          * Plymouth may set whatever it wants to set, and we don't
 234          * interfere with that. */
 235
 236         /* Disable exclusive mode, just in case */
 237         (void) ioctl(fd, TIOCNXCL);
 238
 239         /* Switch to text mode */
 240         if (switch_to_text)
 241                 (void) ioctl(fd, KDSETMODE, KD_TEXT);
 242
 243         /* Enable console unicode mode */
 244         (void) ioctl(fd, KDSKBMODE, K_UNICODE);
 245
 246         if (tcgetattr(fd, &termios) < 0) {
 247                 r = -errno;
 248                 goto finish;
 249         }
 250
 251         /* We only reset the stuff that matters to the software. How
 252          * hardware is set up we don't touch assuming that somebody
 253          * else will do that for us */
 254
 255         termios.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | IUCLC);
 256         termios.c_iflag |= ICRNL | IMAXBEL | IUTF8;
 257         termios.c_oflag |= ONLCR;
 258         termios.c_cflag |= CREAD;
 259         termios.c_lflag = ISIG | ICANON | IEXTEN | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOPRT | ECHOKE;
 260
 261         termios.c_cc[VINTR]    =   03;  /* ^C */
 262         termios.c_cc[VQUIT]    =  034;  /* ^\ */
 263         termios.c_cc[VERASE]   = 0177;
 264         termios.c_cc[VKILL]    =  025;  /* ^X */
 265         termios.c_cc[VEOF]     =   04;  /* ^D */
 266         termios.c_cc[VSTART]   =  021;  /* ^Q */
 267         termios.c_cc[VSTOP]    =  023;  /* ^S */
 268         termios.c_cc[VSUSP]    =  032;  /* ^Z */
 269         termios.c_cc[VLNEXT]   =  026;  /* ^V */
 270         termios.c_cc[VWERASE]  =  027;  /* ^W */
 271         termios.c_cc[VREPRINT] =  022;  /* ^R */
 272         termios.c_cc[VEOL]     =    0;
 273         termios.c_cc[VEOL2]    =    0;
 274
 275         termios.c_cc[VTIME]  = 0;
 276         termios.c_cc[VMIN]   = 1;
 277
 278         if (tcsetattr(fd, TCSANOW, &termios) < 0)
 279                 r = -errno;
 280
 281 finish:
 282         /* Just in case, flush all crap out */
 283         (void) tcflush(fd, TCIOFLUSH);
 284
 285         return r;
 286 }
 287
 288 int reset_terminal(const char *name) {
 289         _cleanup_close_ int fd = -1;
 290
 291         /* We open the terminal with O_NONBLOCK here, to ensure we
 292          * don't block on carrier if this is a terminal with carrier
 293          * configured. */
 294
 295         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 296         if (fd < 0)
 297                 return fd;
 298
 299         return reset_terminal_fd(fd, true);
 300 }
 301
 302 int open_terminal(const char *name, int mode) {
 303         int fd, r;
 304         unsigned c = 0;
 305
 306         /*
 307          * If a TTY is in the process of being closed opening it might
 308          * cause EIO. This is horribly awful, but unlikely to be
 309          * changed in the kernel. Hence we work around this problem by
 310          * retrying a couple of times.
 311          *
 312          * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
 313          */
 314
 315         if (mode & O_CREAT)
 316                 return -EINVAL;
 317
 318         for (;;) {
 319                 fd = open(name, mode, 0);
 320                 if (fd >= 0)
 321                         break;
 322
 323                 if (errno != EIO)
 324                         return -errno;
 325
 326                 /* Max 1s in total */
 327                 if (c >= 20)
 328                         return -errno;
 329
 330                 usleep(50 * USEC_PER_MSEC);
 331                 c++;
 332         }
 333
 334         r = isatty(fd);
 335         if (r < 0) {
 336                 safe_close(fd);
 337                 return -errno;
 338         }
 339
 340         if (!r) {
 341                 safe_close(fd);
 342                 return -ENOTTY;
 343         }
 344
 345         return fd;
 346 }
 347
 348 int acquire_terminal(
 349                 const char *name,
 350                 bool fail,
 351                 bool force,
 352                 bool ignore_tiocstty_eperm,
 353                 usec_t timeout) {
 354
 355         int fd = -1, notify = -1, r = 0, wd = -1;
 356         usec_t ts = 0;
 357
 358         assert(name);
 359
 360         /* We use inotify to be notified when the tty is closed. We
 361          * create the watch before checking if we can actually acquire
 362          * it, so that we don't lose any event.
 363          *
 364          * Note: strictly speaking this actually watches for the
 365          * device being closed, it does *not* really watch whether a
 366          * tty loses its controlling process. However, unless some
 367          * rogue process uses TIOCNOTTY on /dev/tty *after* closing
 368          * its tty otherwise this will not become a problem. As long
 369          * as the administrator makes sure not configure any service
 370          * on the same tty as an untrusted user this should not be a
 371          * problem. (Which he probably should not do anyway.) */
 372
 373         if (timeout != USEC_INFINITY)
 374                 ts = now(CLOCK_MONOTONIC);
 375
 376         if (!fail && !force) {
 377                 notify = inotify_init1(IN_CLOEXEC | (timeout != USEC_INFINITY ? IN_NONBLOCK : 0));
 378                 if (notify < 0) {
 379                         r = -errno;
 380                         goto fail;
 381                 }
 382
 383                 wd = inotify_add_watch(notify, name, IN_CLOSE);
 384                 if (wd < 0) {
 385                         r = -errno;
 386                         goto fail;
 387                 }
 388         }
 389
 390         for (;;) {
 391                 struct sigaction sa_old, sa_new = {
 392                         .sa_handler = SIG_IGN,
 393                         .sa_flags = SA_RESTART,
 394                 };
 395
 396                 if (notify >= 0) {
 397                         r = flush_fd(notify);
 398                         if (r < 0)
 399                                 goto fail;
 400                 }
 401
 402                 /* We pass here O_NOCTTY only so that we can check the return
 403                  * value TIOCSCTTY and have a reliable way to figure out if we
 404                  * successfully became the controlling process of the tty */
 405                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 406                 if (fd < 0)
 407                         return fd;
 408
 409                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 410                  * if we already own the tty. */
 411                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 412
 413                 /* First, try to get the tty */
 414                 if (ioctl(fd, TIOCSCTTY, force) < 0)
 415                         r = -errno;
 416
 417                 assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 418
 419                 /* Sometimes it makes sense to ignore TIOCSCTTY
 420                  * returning EPERM, i.e. when very likely we already
 421                  * are have this controlling terminal. */
 422                 if (r < 0 && r == -EPERM && ignore_tiocstty_eperm)
 423                         r = 0;
 424
 425                 if (r < 0 && (force || fail || r != -EPERM))
 426                         goto fail;
 427
 428                 if (r >= 0)
 429                         break;
 430
 431                 assert(!fail);
 432                 assert(!force);
 433                 assert(notify >= 0);
 434
 435                 for (;;) {
 436                         union inotify_event_buffer buffer;
 437                         struct inotify_event *e;
 438                         ssize_t l;
 439
 440                         if (timeout != USEC_INFINITY) {
 441                                 usec_t n;
 442
 443                                 n = now(CLOCK_MONOTONIC);
 444                                 if (ts + timeout < n) {
 445                                         r = -ETIMEDOUT;
 446                                         goto fail;
 447                                 }
 448
 449                                 r = fd_wait_for_event(fd, POLLIN, ts + timeout - n);
 450                                 if (r < 0)
 451                                         goto fail;
 452
 453                                 if (r == 0) {
 454                                         r = -ETIMEDOUT;
 455                                         goto fail;
 456                                 }
 457                         }
 458
 459                         l = read(notify, &buffer, sizeof(buffer));
 460                         if (l < 0) {
 461                                 if (errno == EINTR || errno == EAGAIN)
 462                                         continue;
 463
 464                                 r = -errno;
 465                                 goto fail;
 466                         }
 467
 468                         FOREACH_INOTIFY_EVENT(e, buffer, l) {
 469                                 if (e->wd != wd || !(e->mask & IN_CLOSE)) {
 470                                         r = -EIO;
 471                                         goto fail;
 472                                 }
 473                         }
 474
 475                         break;
 476                 }
 477
 478                 /* We close the tty fd here since if the old session
 479                  * ended our handle will be dead. It's important that
 480                  * we do this after sleeping, so that we don't enter
 481                  * an endless loop. */
 482                 fd = safe_close(fd);
 483         }
 484
 485         safe_close(notify);
 486
 487         return fd;
 488
 489 fail:
 490         safe_close(fd);
 491         safe_close(notify);
 492
 493         return r;
 494 }
 495
 496 int release_terminal(void) {
 497         static const struct sigaction sa_new = {
 498                 .sa_handler = SIG_IGN,
 499                 .sa_flags = SA_RESTART,
 500         };
 501
 502         _cleanup_close_ int fd = -1;
 503         struct sigaction sa_old;
 504         int r = 0;
 505
 506         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 507         if (fd < 0)
 508                 return -errno;
 509
 510         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
 511          * by our own TIOCNOTTY */
 512         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 513
 514         if (ioctl(fd, TIOCNOTTY) < 0)
 515                 r = -errno;
 516
 517         assert_se(sigaction(SIGHUP, &sa_old, NULL) == 0);
 518
 519         return r;
 520 }
 521
 522 int terminal_vhangup_fd(int fd) {
 523         assert(fd >= 0);
 524
 525         if (ioctl(fd, TIOCVHANGUP) < 0)
 526                 return -errno;
 527
 528         return 0;
 529 }
 530
 531 int terminal_vhangup(const char *name) {
 532         _cleanup_close_ int fd;
 533
 534         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 535         if (fd < 0)
 536                 return fd;
 537
 538         return terminal_vhangup_fd(fd);
 539 }
 540
 541 int vt_disallocate(const char *name) {
 542         _cleanup_close_ int fd = -1;
 543         unsigned u;
 544         int r;
 545
 546         /* Deallocate the VT if possible. If not possible
 547          * (i.e. because it is the active one), at least clear it
 548          * entirely (including the scrollback buffer) */
 549
 550         if (!startswith(name, "/dev/"))
 551                 return -EINVAL;
 552
 553         if (!tty_is_vc(name)) {
 554                 /* So this is not a VT. I guess we cannot deallocate
 555                  * it then. But let's at least clear the screen */
 556
 557                 fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 558                 if (fd < 0)
 559                         return fd;
 560
 561                 loop_write(fd,
 562                            "\033[r"    /* clear scrolling region */
 563                            "\033[H"    /* move home */
 564                            "\033[2J",  /* clear screen */
 565                            10, false);
 566                 return 0;
 567         }
 568
 569         if (!startswith(name, "/dev/tty"))
 570                 return -EINVAL;
 571
 572         r = safe_atou(name+8, &u);
 573         if (r < 0)
 574                 return r;
 575
 576         if (u <= 0)
 577                 return -EINVAL;
 578
 579         /* Try to deallocate */
 580         fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
 581         if (fd < 0)
 582                 return fd;
 583
 584         r = ioctl(fd, VT_DISALLOCATE, u);
 585         fd = safe_close(fd);
 586
 587         if (r >= 0)
 588                 return 0;
 589
 590         if (errno != EBUSY)
 591                 return -errno;
 592
 593         /* Couldn't deallocate, so let's clear it fully with
 594          * scrollback */
 595         fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
 596         if (fd < 0)
 597                 return fd;
 598
 599         loop_write(fd,
 600                    "\033[r"   /* clear scrolling region */
 601                    "\033[H"   /* move home */
 602                    "\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
 603                    10, false);
 604         return 0;
 605 }
 606
 607 int make_console_stdio(void) {
 608         int fd, r;
 609
 610         /* Make /dev/console the controlling terminal and stdin/stdout/stderr */
 611
 612         fd = acquire_terminal("/dev/console", false, true, true, USEC_INFINITY);
 613         if (fd < 0)
 614                 return log_error_errno(fd, "Failed to acquire terminal: %m");
 615
 616         r = reset_terminal_fd(fd, true);
 617         if (r < 0)
 618                 log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
 619
 620         r = make_stdio(fd);
 621         if (r < 0)
 622                 return log_error_errno(r, "Failed to duplicate terminal fd: %m");
 623
 624         return 0;
 625 }
 626
 627 int status_vprintf(const char *status, bool ellipse, bool ephemeral, const char *format, va_list ap) {
 628         static const char status_indent[] = "         "; /* "[" STATUS "] " */
 629         _cleanup_free_ char *s = NULL;
 630         _cleanup_close_ int fd = -1;
 631         struct iovec iovec[6] = {};
 632         int n = 0;
 633         static bool prev_ephemeral;
 634
 635         assert(format);
 636
 637         /* This is independent of logging, as status messages are
 638          * optional and go exclusively to the console. */
 639
 640         if (vasprintf(&s, format, ap) < 0)
 641                 return log_oom();
 642
 643         fd = open_terminal("/dev/console", O_WRONLY|O_NOCTTY|O_CLOEXEC);
 644         if (fd < 0)
 645                 return fd;
 646
 647         if (ellipse) {
 648                 char *e;
 649                 size_t emax, sl;
 650                 int c;
 651
 652                 c = fd_columns(fd);
 653                 if (c <= 0)
 654                         c = 80;
 655
 656                 sl = status ? sizeof(status_indent)-1 : 0;
 657
 658                 emax = c - sl - 1;
 659                 if (emax < 3)
 660                         emax = 3;
 661
 662                 e = ellipsize(s, emax, 50);
 663                 if (e) {
 664                         free(s);
 665                         s = e;
 666                 }
 667         }
 668
 669         if (prev_ephemeral)
 670                 IOVEC_SET_STRING(iovec[n++], "\r" ANSI_ERASE_TO_END_OF_LINE);
 671         prev_ephemeral = ephemeral;
 672
 673         if (status) {
 674                 if (!isempty(status)) {
 675                         IOVEC_SET_STRING(iovec[n++], "[");
 676                         IOVEC_SET_STRING(iovec[n++], status);
 677                         IOVEC_SET_STRING(iovec[n++], "] ");
 678                 } else
 679                         IOVEC_SET_STRING(iovec[n++], status_indent);
 680         }
 681
 682         IOVEC_SET_STRING(iovec[n++], s);
 683         if (!ephemeral)
 684                 IOVEC_SET_STRING(iovec[n++], "\n");
 685
 686         if (writev(fd, iovec, n) < 0)
 687                 return -errno;
 688
 689         return 0;
 690 }
 691
 692 int status_printf(const char *status, bool ellipse, bool ephemeral, const char *format, ...) {
 693         va_list ap;
 694         int r;
 695
 696         assert(format);
 697
 698         va_start(ap, format);
 699         r = status_vprintf(status, ellipse, ephemeral, format, ap);
 700         va_end(ap);
 701
 702         return r;
 703 }
 704
 705 bool tty_is_vc(const char *tty) {
 706         assert(tty);
 707
 708         return vtnr_from_tty(tty) >= 0;
 709 }
 710
 711 bool tty_is_console(const char *tty) {
 712         assert(tty);
 713
 714         if (startswith(tty, "/dev/"))
 715                 tty += 5;
 716
 717         return streq(tty, "console");
 718 }
 719
 720 int vtnr_from_tty(const char *tty) {
 721         int i, r;
 722
 723         assert(tty);
 724
 725         if (startswith(tty, "/dev/"))
 726                 tty += 5;
 727
 728         if (!startswith(tty, "tty") )
 729                 return -EINVAL;
 730
 731         if (tty[3] < '0' || tty[3] > '9')
 732                 return -EINVAL;
 733
 734         r = safe_atoi(tty+3, &i);
 735         if (r < 0)
 736                 return r;
 737
 738         if (i < 0 || i > 63)
 739                 return -EINVAL;
 740
 741         return i;
 742 }
 743
 744 char *resolve_dev_console(char **active) {
 745         char *tty;
 746
 747         /* Resolve where /dev/console is pointing to, if /sys is actually ours
 748          * (i.e. not read-only-mounted which is a sign for container setups) */
 749
 750         if (path_is_read_only_fs("/sys") > 0)
 751                 return NULL;
 752
 753         if (read_one_line_file("/sys/class/tty/console/active", active) < 0)
 754                 return NULL;
 755
 756         /* If multiple log outputs are configured the last one is what
 757          * /dev/console points to */
 758         tty = strrchr(*active, ' ');
 759         if (tty)
 760                 tty++;
 761         else
 762                 tty = *active;
 763
 764         if (streq(tty, "tty0")) {
 765                 char *tmp;
 766
 767                 /* Get the active VC (e.g. tty1) */
 768                 if (read_one_line_file("/sys/class/tty/tty0/active", &tmp) >= 0) {
 769                         free(*active);
 770                         tty = *active = tmp;
 771                 }
 772         }
 773
 774         return tty;
 775 }
 776
 777 bool tty_is_vc_resolve(const char *tty) {
 778         _cleanup_free_ char *active = NULL;
 779
 780         assert(tty);
 781
 782         if (startswith(tty, "/dev/"))
 783                 tty += 5;
 784
 785         if (streq(tty, "console")) {
 786                 tty = resolve_dev_console(&active);
 787                 if (!tty)
 788                         return false;
 789         }
 790
 791         return tty_is_vc(tty);
 792 }
 793
 794 const char *default_term_for_tty(const char *tty) {
 795         assert(tty);
 796
 797         return tty_is_vc_resolve(tty) ? "TERM=linux" : "TERM=vt220";
 798 }
 799
 800 int fd_columns(int fd) {
 801         struct winsize ws = {};
 802
 803         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 804                 return -errno;
 805
 806         if (ws.ws_col <= 0)
 807                 return -EIO;
 808
 809         return ws.ws_col;
 810 }
 811
 812 unsigned columns(void) {
 813         const char *e;
 814         int c;
 815
 816         if (_likely_(cached_columns > 0))
 817                 return cached_columns;
 818
 819         c = 0;
 820         e = getenv("COLUMNS");
 821         if (e)
 822                 (void) safe_atoi(e, &c);
 823
 824         if (c <= 0)
 825                 c = fd_columns(STDOUT_FILENO);
 826
 827         if (c <= 0)
 828                 c = 80;
 829
 830         cached_columns = c;
 831         return cached_columns;
 832 }
 833
 834 int fd_lines(int fd) {
 835         struct winsize ws = {};
 836
 837         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
 838                 return -errno;
 839
 840         if (ws.ws_row <= 0)
 841                 return -EIO;
 842
 843         return ws.ws_row;
 844 }
 845
 846 unsigned lines(void) {
 847         const char *e;
 848         int l;
 849
 850         if (_likely_(cached_lines > 0))
 851                 return cached_lines;
 852
 853         l = 0;
 854         e = getenv("LINES");
 855         if (e)
 856                 (void) safe_atoi(e, &l);
 857
 858         if (l <= 0)
 859                 l = fd_lines(STDOUT_FILENO);
 860
 861         if (l <= 0)
 862                 l = 24;
 863
 864         cached_lines = l;
 865         return cached_lines;
 866 }
 867
 868 /* intended to be used as a SIGWINCH sighandler */
 869 void columns_lines_cache_reset(int signum) {
 870         cached_columns = 0;
 871         cached_lines = 0;
 872 }
 873
 874 bool on_tty(void) {
 875         static int cached_on_tty = -1;
 876
 877         if (_unlikely_(cached_on_tty < 0))
 878                 cached_on_tty = isatty(STDOUT_FILENO) > 0;
 879
 880         return cached_on_tty;
 881 }
 882
 883 int make_stdio(int fd) {
 884         int r, s, t;
 885
 886         assert(fd >= 0);
 887
 888         r = dup2(fd, STDIN_FILENO);
 889         s = dup2(fd, STDOUT_FILENO);
 890         t = dup2(fd, STDERR_FILENO);
 891
 892         if (fd >= 3)
 893                 safe_close(fd);
 894
 895         if (r < 0 || s < 0 || t < 0)
 896                 return -errno;
 897
 898         /* Explicitly unset O_CLOEXEC, since if fd was < 3, then
 899          * dup2() was a NOP and the bit hence possibly set. */
 900         fd_cloexec(STDIN_FILENO, false);
 901         fd_cloexec(STDOUT_FILENO, false);
 902         fd_cloexec(STDERR_FILENO, false);
 903
 904         return 0;
 905 }
 906
 907 int make_null_stdio(void) {
 908         int null_fd;
 909
 910         null_fd = open("/dev/null", O_RDWR|O_NOCTTY);
 911         if (null_fd < 0)
 912                 return -errno;
 913
 914         return make_stdio(null_fd);
 915 }
 916
 917 int getttyname_malloc(int fd, char **ret) {
 918         size_t l = 100;
 919         int r;
 920
 921         assert(fd >= 0);
 922         assert(ret);
 923
 924         for (;;) {
 925                 char path[l];
 926
 927                 r = ttyname_r(fd, path, sizeof(path));
 928                 if (r == 0) {
 929                         const char *p;
 930                         char *c;
 931
 932                         p = startswith(path, "/dev/");
 933                         c = strdup(p ?: path);
 934                         if (!c)
 935                                 return -ENOMEM;
 936
 937                         *ret = c;
 938                         return 0;
 939                 }
 940
 941                 if (r != ERANGE)
 942                         return -r;
 943
 944                 l *= 2;
 945         }
 946
 947         return 0;
 948 }
 949
 950 int getttyname_harder(int fd, char **r) {
 951         int k;
 952         char *s = NULL;
 953
 954         k = getttyname_malloc(fd, &s);
 955         if (k < 0)
 956                 return k;
 957
 958         if (streq(s, "tty")) {
 959                 free(s);
 960                 return get_ctty(0, NULL, r);
 961         }
 962
 963         *r = s;
 964         return 0;
 965 }
 966
 967 int get_ctty_devnr(pid_t pid, dev_t *d) {
 968         int r;
 969         _cleanup_free_ char *line = NULL;
 970         const char *p;
 971         unsigned long ttynr;
 972
 973         assert(pid >= 0);
 974
 975         p = procfs_file_alloca(pid, "stat");
 976         r = read_one_line_file(p, &line);
 977         if (r < 0)
 978                 return r;
 979
 980         p = strrchr(line, ')');
 981         if (!p)
 982                 return -EIO;
 983
 984         p++;
 985
 986         if (sscanf(p, " "
 987                    "%*c "  /* state */
 988                    "%*d "  /* ppid */
 989                    "%*d "  /* pgrp */
 990                    "%*d "  /* session */
 991                    "%lu ", /* ttynr */
 992                    &ttynr) != 1)
 993                 return -EIO;
 994
 995         if (major(ttynr) == 0 && minor(ttynr) == 0)
 996                 return -ENXIO;
 997
 998         if (d)
 999                 *d = (dev_t) ttynr;
1000
1001         return 0;
1002 }
1003
1004 int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
1005         char fn[sizeof("/dev/char/")-1 + 2*DECIMAL_STR_MAX(unsigned) + 1 + 1], *b = NULL;
1006         _cleanup_free_ char *s = NULL;
1007         const char *p;
1008         dev_t devnr;
1009         int k;
1010
1011         assert(r);
1012
1013         k = get_ctty_devnr(pid, &devnr);
1014         if (k < 0)
1015                 return k;
1016
1017         sprintf(fn, "/dev/char/%u:%u", major(devnr), minor(devnr));
1018
1019         k = readlink_malloc(fn, &s);
1020         if (k < 0) {
1021
1022                 if (k != -ENOENT)
1023                         return k;
1024
1025                 /* This is an ugly hack */
1026                 if (major(devnr) == 136) {
1027                         if (asprintf(&b, "pts/%u", minor(devnr)) < 0)
1028                                 return -ENOMEM;
1029                 } else {
1030                         /* Probably something like the ptys which have no
1031                          * symlink in /dev/char. Let's return something
1032                          * vaguely useful. */
1033
1034                         b = strdup(fn + 5);
1035                         if (!b)
1036                                 return -ENOMEM;
1037                 }
1038         } else {
1039                 if (startswith(s, "/dev/"))
1040                         p = s + 5;
1041                 else if (startswith(s, "../"))
1042                         p = s + 3;
1043                 else
1044                         p = s;
1045
1046                 b = strdup(p);
1047                 if (!b)
1048                         return -ENOMEM;
1049         }
1050
1051         *r = b;
1052         if (_devnr)
1053                 *_devnr = devnr;
1054
1055         return 0;
1056 }
1057
1058 int ptsname_malloc(int fd, char **ret) {
1059         size_t l = 100;
1060
1061         assert(fd >= 0);
1062         assert(ret);
1063
1064         for (;;) {
1065                 char *c;
1066
1067                 c = new(char, l);
1068                 if (!c)
1069                         return -ENOMEM;
1070
1071                 if (ptsname_r(fd, c, l) == 0) {
1072                         *ret = c;
1073                         return 0;
1074                 }
1075                 if (errno != ERANGE) {
1076                         free(c);
1077                         return -errno;
1078                 }
1079
1080                 free(c);
1081                 l *= 2;
1082         }
1083 }
1084
1085 int ptsname_namespace(int pty, char **ret) {
1086         int no = -1, r;
1087
1088         /* Like ptsname(), but doesn't assume that the path is
1089          * accessible in the local namespace. */
1090
1091         r = ioctl(pty, TIOCGPTN, &no);
1092         if (r < 0)
1093                 return -errno;
1094
1095         if (no < 0)
1096                 return -EIO;
1097
1098         if (asprintf(ret, "/dev/pts/%i", no) < 0)
1099                 return -ENOMEM;
1100
1101         return 0;
1102 }
1103
1104 int openpt_in_namespace(pid_t pid, int flags) {
1105         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1106         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1107         siginfo_t si;
1108         pid_t child;
1109         int r;
1110
1111         assert(pid > 0);
1112
1113         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1114         if (r < 0)
1115                 return r;
1116
1117         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1118                 return -errno;
1119
1120         child = fork();
1121         if (child < 0)
1122                 return -errno;
1123
1124         if (child == 0) {
1125                 int master;
1126
1127                 pair[0] = safe_close(pair[0]);
1128
1129                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1130                 if (r < 0)
1131                         _exit(EXIT_FAILURE);
1132
1133                 master = posix_openpt(flags|O_NOCTTY|O_CLOEXEC);
1134                 if (master < 0)
1135                         _exit(EXIT_FAILURE);
1136
1137                 if (unlockpt(master) < 0)
1138                         _exit(EXIT_FAILURE);
1139
1140                 if (send_one_fd(pair[1], master, 0) < 0)
1141                         _exit(EXIT_FAILURE);
1142
1143                 _exit(EXIT_SUCCESS);
1144         }
1145
1146         pair[1] = safe_close(pair[1]);
1147
1148         r = wait_for_terminate(child, &si);
1149         if (r < 0)
1150                 return r;
1151         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1152                 return -EIO;
1153
1154         return receive_one_fd(pair[0], 0);
1155 }
1156
1157 int open_terminal_in_namespace(pid_t pid, const char *name, int mode) {
1158         _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
1159         _cleanup_close_pair_ int pair[2] = { -1, -1 };
1160         siginfo_t si;
1161         pid_t child;
1162         int r;
1163
1164         r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
1165         if (r < 0)
1166                 return r;
1167
1168         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
1169                 return -errno;
1170
1171         child = fork();
1172         if (child < 0)
1173                 return -errno;
1174
1175         if (child == 0) {
1176                 int master;
1177
1178                 pair[0] = safe_close(pair[0]);
1179
1180                 r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
1181                 if (r < 0)
1182                         _exit(EXIT_FAILURE);
1183
1184                 master = open_terminal(name, mode|O_NOCTTY|O_CLOEXEC);
1185                 if (master < 0)
1186                         _exit(EXIT_FAILURE);
1187
1188                 if (send_one_fd(pair[1], master, 0) < 0)
1189                         _exit(EXIT_FAILURE);
1190
1191                 _exit(EXIT_SUCCESS);
1192         }
1193
1194         pair[1] = safe_close(pair[1]);
1195
1196         r = wait_for_terminate(child, &si);
1197         if (r < 0)
1198                 return r;
1199         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
1200                 return -EIO;
1201
1202         return receive_one_fd(pair[0], 0);
1203 }