src/subshell.c

   1 /*
   2    Concurrent shell support for the Midnight Commander
   3
   4    Copyright (C) 1994-2015
   5    Free Software Foundation, Inc.
   6
   7    Written by:
   8    Slava Zanko <slavazanko@gmail.com>, 2013
   9
  10    This file is part of the Midnight Commander.
  11
  12    The Midnight Commander is free software: you can redistribute it
  13    and/or modify it under the terms of the GNU General Public License as
  14    published by the Free Software Foundation, either version 3 of the License,
  15    or (at your option) any later version.
  16
  17    The Midnight Commander is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20    GNU General Public License for more details.
  21
  22    You should have received a copy of the GNU General Public License
  23    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  24  */
  25
  26 /** \file subshell.c
  27  *  \brief Source: concurrent shell support
  28  */
  29
  30 #include <config.h>
  31
  32 #ifndef _GNU_SOURCE
  33 #define _GNU_SOURCE 1
  34 #endif
  35
  36 #include <ctype.h>
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <errno.h>
  40 #include <string.h>
  41 #include <signal.h>
  42 #include <fcntl.h>
  43 #include <sys/types.h>
  44 #include <sys/wait.h>
  45 #ifdef HAVE_SYS_IOCTL_H
  46 #include <sys/ioctl.h>
  47 #endif
  48 #include <termios.h>
  49
  50 #ifdef HAVE_STROPTS_H
  51 #include <stropts.h>            /* For I_PUSH */
  52 #endif /* HAVE_STROPTS_H */
  53
  54 #include "lib/global.h"
  55
  56 #include "lib/unixcompat.h"
  57 #include "lib/tty/tty.h"        /* LINES */
  58 #include "lib/tty/key.h"        /* XCTRL */
  59 #include "lib/vfs/vfs.h"
  60 #include "lib/strutil.h"
  61 #include "lib/mcconfig.h"
  62 #include "lib/util.h"
  63 #include "lib/widget.h"
  64
  65 #include "filemanager/midnight.h"       /* current_panel */
  66
  67 #include "consaver/cons.saver.h"        /* handle_console() */
  68 #include "setup.h"
  69 #include "subshell.h"
  70
  71 /*** global variables ****************************************************************************/
  72
  73 /* State of the subshell:
  74  * INACTIVE: the default state; awaiting a command
  75  * ACTIVE: remain in the shell until the user hits 'subshell_switch_key'
  76  * RUNNING_COMMAND: return to MC when the current command finishes */
  77 enum subshell_state_enum subshell_state;
  78
  79 /* Holds the latest prompt captured from the subshell */
  80 GString *subshell_prompt = NULL;
  81
  82 /* Subshell: if set, then the prompt was not saved on CONSOLE_SAVE */
  83 /* We need to paint it after CONSOLE_RESTORE, see: load_prompt */
  84 gboolean update_subshell_prompt = FALSE;
  85
  86 /*** file scope macro definitions ****************************************************************/
  87
  88 #ifndef WEXITSTATUS
  89 #define WEXITSTATUS(stat_val) ((unsigned)(stat_val) >> 8)
  90 #endif
  91
  92 #ifndef WIFEXITED
  93 #define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
  94 #endif
  95
  96 /* Initial length of the buffer for the subshell's prompt */
  97 #define INITIAL_PROMPT_SIZE 10
  98
  99 /* Used by the child process to indicate failure to start the subshell */
 100 #define FORK_FAILURE 69         /* Arbitrary */
 101
 102 /* Length of the buffer for all I/O with the subshell */
 103 #define PTY_BUFFER_SIZE BUF_SMALL       /* Arbitrary; but keep it >= 80 */
 104
 105 /*** file scope type declarations ****************************************************************/
 106
 107 /* For pipes */
 108 enum
 109 {
 110     READ = 0,
 111     WRITE = 1
 112 };
 113
 114 /* Subshell type (gleaned from the SHELL environment variable, if available) */
 115 static enum
 116 {
 117     BASH,
 118     TCSH,
 119     ZSH,
 120     FISH
 121 } subshell_type;
 122
 123 /*** file scope variables ************************************************************************/
 124
 125 /* tcsh closes all non-standard file descriptors, so we have to use a pipe */
 126 static char tcsh_fifo[128];
 127
 128 static int subshell_pty_slave = -1;
 129
 130 /* The key for switching back to MC from the subshell */
 131 /* *INDENT-OFF* */
 132 static const char subshell_switch_key = XCTRL ('o') & 255;
 133 /* *INDENT-ON* */
 134
 135 /* For reading/writing on the subshell's pty */
 136 static char pty_buffer[PTY_BUFFER_SIZE] = "\0";
 137
 138 /* To pass CWD info from the subshell to MC */
 139 static int subshell_pipe[2];
 140
 141 /* The subshell's process ID */
 142 static pid_t subshell_pid = 1;
 143
 144 /* One extra char for final '\n' */
 145 static char subshell_cwd[MC_MAXPATHLEN + 1];
 146
 147 /* Flag to indicate whether the subshell is ready for next command */
 148 static int subshell_ready;
 149
 150 /* The following two flags can be changed by the SIGCHLD handler. This is */
 151 /* OK, because the 'int' type is updated atomically on all known machines */
 152 static volatile int subshell_alive, subshell_stopped;
 153
 154 /* We store the terminal's initial mode here so that we can configure
 155    the pty similarly, and also so we can restore the real terminal to
 156    sanity if we have to exit abruptly */
 157 static struct termios shell_mode;
 158
 159 /* This is a transparent mode for the terminal where MC is running on */
 160 /* It is used when the shell is active, so that the control signals */
 161 /* are delivered to the shell pty */
 162 static struct termios raw_mode;
 163
 164 /* --------------------------------------------------------------------------------------------- */
 165 /*** file scope functions ************************************************************************/
 166 /* --------------------------------------------------------------------------------------------- */
 167 /**
 168  *  Write all data, even if the write() call is interrupted.
 169  */
 170
 171 static ssize_t
 172 write_all (int fd, const void *buf, size_t count)
 173 {
 174     ssize_t written = 0;
 175
 176     while (count > 0)
 177     {
 178         ssize_t ret;
 179
 180         ret = write (fd, (const unsigned char *) buf + written, count);
 181         if (ret < 0)
 182         {
 183             if (errno == EINTR)
 184             {
 185                 if (mc_global.tty.winch_flag != 0)
 186                     tty_change_screen_size ();
 187
 188                 continue;
 189             }
 190
 191             return written > 0 ? written : ret;
 192         }
 193         count -= ret;
 194         written += ret;
 195     }
 196     return written;
 197 }
 198
 199 /* --------------------------------------------------------------------------------------------- */
 200 /**
 201  *  Prepare child process to running the shell and run it.
 202  *
 203  *  Modifies the global variables (in the child process only):
 204  *      shell_mode
 205  *
 206  *  Returns: never.
 207  */
 208
 209 static void
 210 init_subshell_child (const char *pty_name)
 211 {
 212     char *init_file = NULL;
 213     pid_t mc_sid;
 214
 215     (void) pty_name;
 216     setsid ();                  /* Get a fresh terminal session */
 217
 218     /* Make sure that it has become our controlling terminal */
 219
 220     /* Redundant on Linux and probably most systems, but just in case: */
 221
 222 #ifdef TIOCSCTTY
 223     ioctl (subshell_pty_slave, TIOCSCTTY, 0);
 224 #endif
 225
 226     /* Configure its terminal modes and window size */
 227
 228     /* Set up the pty with the same termios flags as our own tty */
 229     if (tcsetattr (subshell_pty_slave, TCSANOW, &shell_mode))
 230     {
 231         fprintf (stderr, "Cannot set pty terminal modes: %s\r\n", unix_error_string (errno));
 232         my_exit (FORK_FAILURE);
 233     }
 234
 235     /* Set the pty's size (80x25 by default on Linux) according to the */
 236     /* size of the real terminal as calculated by ncurses, if possible */
 237     tty_resize (subshell_pty_slave);
 238
 239     /* Set up the subshell's environment and init file name */
 240
 241     /* It simplifies things to change to our home directory here, */
 242     /* and the user's startup file may do a 'cd' command anyway   */
 243     {
 244         int ret;
 245         ret = chdir (mc_config_get_home_dir ());        /* FIXME? What about when we re-run the subshell? */
 246         (void) ret;
 247     }
 248
 249     /* Set MC_SID to prevent running one mc from another */
 250     mc_sid = getsid (0);
 251     if (mc_sid != -1)
 252     {
 253         char sid_str[BUF_SMALL];
 254         g_snprintf (sid_str, sizeof (sid_str), "MC_SID=%ld", (long) mc_sid);
 255         putenv (g_strdup (sid_str));
 256     }
 257
 258     switch (subshell_type)
 259     {
 260     case BASH:
 261         init_file = mc_config_get_full_path ("bashrc");
 262
 263         if (access (init_file, R_OK) == -1)
 264         {
 265             g_free (init_file);
 266             init_file = g_strdup (".bashrc");
 267         }
 268
 269         /* Make MC's special commands not show up in bash's history */
 270         putenv ((char *) "HISTCONTROL=ignorespace");
 271
 272         /* Allow alternative readline settings for MC */
 273         {
 274             char *input_file = mc_config_get_full_path ("inputrc");
 275             if (access (input_file, R_OK) == 0)
 276             {
 277                 char *putenv_str = g_strconcat ("INPUTRC=", input_file, NULL);
 278                 putenv (putenv_str);
 279                 g_free (putenv_str);
 280             }
 281             g_free (input_file);
 282         }
 283
 284         break;
 285
 286         /* TODO: Find a way to pass initfile to TCSH and ZSH */
 287     case TCSH:
 288     case ZSH:
 289     case FISH:
 290         break;
 291
 292     default:
 293         fprintf (stderr, __FILE__ ": unimplemented subshell type %d\r\n", subshell_type);
 294         my_exit (FORK_FAILURE);
 295     }
 296
 297     /* Attach all our standard file descriptors to the pty */
 298
 299     /* This is done just before the fork, because stderr must still      */
 300     /* be connected to the real tty during the above error messages; */
 301     /* otherwise the user will never see them.                   */
 302
 303     dup2 (subshell_pty_slave, STDIN_FILENO);
 304     dup2 (subshell_pty_slave, STDOUT_FILENO);
 305     dup2 (subshell_pty_slave, STDERR_FILENO);
 306
 307     close (subshell_pipe[READ]);
 308     close (subshell_pty_slave); /* These may be FD_CLOEXEC, but just in case... */
 309     /* Close master side of pty.  This is important; apart from */
 310     /* freeing up the descriptor for use in the subshell, it also       */
 311     /* means that when MC exits, the subshell will get a SIGHUP and     */
 312     /* exit too, because there will be no more descriptors pointing     */
 313     /* at the master side of the pty and so it will disappear.  */
 314     close (mc_global.tty.subshell_pty);
 315
 316     /* Execute the subshell at last */
 317
 318     switch (subshell_type)
 319     {
 320     case BASH:
 321         execl (mc_global.tty.shell, "bash", "-rcfile", init_file, (char *) NULL);
 322         break;
 323
 324     case TCSH:
 325         execl (mc_global.tty.shell, "tcsh", (char *) NULL);
 326         break;
 327
 328     case ZSH:
 329         /* Use -g to exclude cmds beginning with space from history
 330          * and -Z to use the line editor on non-interactive term */
 331         execl (mc_global.tty.shell, "zsh", "-Z", "-g", (char *) NULL);
 332
 333         break;
 334
 335     case FISH:
 336         execl (mc_global.tty.shell, "fish", (char *) NULL);
 337         break;
 338     }
 339
 340     /* If we get this far, everything failed miserably */
 341     g_free (init_file);
 342     my_exit (FORK_FAILURE);
 343 }
 344
 345
 346 /* --------------------------------------------------------------------------------------------- */
 347 /**
 348  * Check MC_SID to prevent running one mc from another.
 349  * Return:
 350  * 0 if no parent mc in our session was found,
 351  * 1 if parent mc was found and the user wants to continue,
 352  * 2 if parent mc was found and the user wants to quit mc.
 353  */
 354
 355 static int
 356 check_sid (void)
 357 {
 358     pid_t my_sid, old_sid;
 359     const char *sid_str;
 360     int r;
 361
 362     sid_str = getenv ("MC_SID");
 363     if (!sid_str)
 364         return 0;
 365
 366     old_sid = (pid_t) strtol (sid_str, NULL, 0);
 367     if (!old_sid)
 368         return 0;
 369
 370     my_sid = getsid (0);
 371     if (my_sid == -1)
 372         return 0;
 373
 374     /* The parent mc is in a different session, it's OK */
 375     if (old_sid != my_sid)
 376         return 0;
 377
 378     r = query_dialog (_("Warning"),
 379                       _("GNU Midnight Commander is already\n"
 380                         "running on this terminal.\n"
 381                         "Subshell support will be disabled."), D_ERROR, 2, _("&OK"), _("&Quit"));
 382     if (r != 0)
 383     {
 384         return 2;
 385     }
 386
 387     return 1;
 388 }
 389
 390 /* --------------------------------------------------------------------------------------------- */
 391
 392 static void
 393 init_raw_mode ()
 394 {
 395     static int initialized = 0;
 396
 397     /* MC calls tty_reset_shell_mode() in pre_exec() to set the real tty to its */
 398     /* original settings.  However, here we need to make this tty very raw,     */
 399     /* so that all keyboard signals, XON/XOFF, etc. will get through to the     */
 400     /* pty.  So, instead of changing the code for execute(), pre_exec(),        */
 401     /* etc, we just set up the modes we need here, before each command.         */
 402
 403     if (initialized == 0)       /* First time: initialise 'raw_mode' */
 404     {
 405         tcgetattr (STDOUT_FILENO, &raw_mode);
 406         raw_mode.c_lflag &= ~ICANON;    /* Disable line-editing chars, etc.   */
 407         raw_mode.c_lflag &= ~ISIG;      /* Disable intr, quit & suspend chars */
 408         raw_mode.c_lflag &= ~ECHO;      /* Disable input echoing              */
 409         raw_mode.c_iflag &= ~IXON;      /* Pass ^S/^Q to subshell undisturbed */
 410         raw_mode.c_iflag &= ~ICRNL;     /* Don't translate CRs into LFs       */
 411         raw_mode.c_oflag &= ~OPOST;     /* Don't postprocess output           */
 412         raw_mode.c_cc[VTIME] = 0;       /* IE: wait forever, and return as    */
 413         raw_mode.c_cc[VMIN] = 1;        /* soon as a character is available   */
 414         initialized = 1;
 415     }
 416 }
 417
 418 /* --------------------------------------------------------------------------------------------- */
 419 /**
 420  * Wait until the subshell dies or stops.  If it stops, make it resume.
 421  * Possibly modifies the globals 'subshell_alive' and 'subshell_stopped'
 422  */
 423
 424 static void
 425 synchronize (void)
 426 {
 427     sigset_t sigchld_mask, old_mask;
 428
 429     sigemptyset (&sigchld_mask);
 430     sigaddset (&sigchld_mask, SIGCHLD);
 431     sigprocmask (SIG_BLOCK, &sigchld_mask, &old_mask);
 432
 433     /*
 434      * SIGCHLD should not be blocked, but we unblock it just in case.
 435      * This is known to be useful for cygwin 1.3.12 and older.
 436      */
 437     sigdelset (&old_mask, SIGCHLD);
 438
 439     /* Wait until the subshell has stopped */
 440     while (subshell_alive && !subshell_stopped)
 441         sigsuspend (&old_mask);
 442
 443     if (subshell_state != ACTIVE)
 444     {
 445         /* Discard all remaining data from stdin to the subshell */
 446         tcflush (subshell_pty_slave, TCIFLUSH);
 447     }
 448
 449     subshell_stopped = FALSE;
 450     kill (subshell_pid, SIGCONT);
 451
 452     sigprocmask (SIG_SETMASK, &old_mask, NULL);
 453     /* We can't do any better without modifying the shell(s) */
 454 }
 455
 456 /* --------------------------------------------------------------------------------------------- */
 457 /** Feed the subshell our keyboard input until it says it's finished */
 458
 459 static gboolean
 460 feed_subshell (int how, int fail_on_error)
 461 {
 462     fd_set read_set;            /* For 'select' */
 463     int bytes;                  /* For the return value from 'read' */
 464     int i;                      /* Loop counter */
 465
 466     struct timeval wtime;       /* Maximum time we wait for the subshell */
 467     struct timeval *wptr;
 468
 469     /* we wait up to 10 seconds if fail_on_error, forever otherwise */
 470     wtime.tv_sec = 10;
 471     wtime.tv_usec = 0;
 472     wptr = fail_on_error ? &wtime : NULL;
 473
 474     while (TRUE)
 475     {
 476         int maxfdp;
 477
 478         if (!subshell_alive)
 479             return FALSE;
 480
 481         /* Prepare the file-descriptor set and call 'select' */
 482
 483         FD_ZERO (&read_set);
 484         FD_SET (mc_global.tty.subshell_pty, &read_set);
 485         FD_SET (subshell_pipe[READ], &read_set);
 486         maxfdp = max (mc_global.tty.subshell_pty, subshell_pipe[READ]);
 487         if (how == VISIBLY)
 488         {
 489             FD_SET (STDIN_FILENO, &read_set);
 490             maxfdp = max (maxfdp, STDIN_FILENO);
 491         }
 492
 493         if (select (maxfdp + 1, &read_set, NULL, NULL, wptr) == -1)
 494         {
 495             /* Despite using SA_RESTART, we still have to check for this */
 496             if (errno == EINTR)
 497             {
 498                 if (mc_global.tty.winch_flag != 0)
 499                     tty_change_screen_size ();
 500
 501                 continue;       /* try all over again */
 502             }
 503             tcsetattr (STDOUT_FILENO, TCSANOW, &shell_mode);
 504             fprintf (stderr, "select (FD_SETSIZE, &read_set...): %s\r\n",
 505                      unix_error_string (errno));
 506             exit (EXIT_FAILURE);
 507         }
 508
 509         if (FD_ISSET (mc_global.tty.subshell_pty, &read_set))
 510             /* Read from the subshell, write to stdout */
 511
 512             /* This loop improves performance by reducing context switches
 513                by a factor of 20 or so... unfortunately, it also hangs MC
 514                randomly, because of an apparent Linux bug.  Investigate. */
 515             /* for (i=0; i<5; ++i)  * FIXME -- experimental */
 516         {
 517             bytes = read (mc_global.tty.subshell_pty, pty_buffer, sizeof (pty_buffer));
 518
 519             /* The subshell has died */
 520             if (bytes == -1 && errno == EIO && !subshell_alive)
 521                 return FALSE;
 522
 523             if (bytes <= 0)
 524             {
 525                 tcsetattr (STDOUT_FILENO, TCSANOW, &shell_mode);
 526                 fprintf (stderr, "read (subshell_pty...): %s\r\n", unix_error_string (errno));
 527                 exit (EXIT_FAILURE);
 528             }
 529
 530             if (how == VISIBLY)
 531                 write_all (STDOUT_FILENO, pty_buffer, bytes);
 532         }
 533
 534         else if (FD_ISSET (subshell_pipe[READ], &read_set))
 535             /* Read the subshell's CWD and capture its prompt */
 536         {
 537             bytes = read (subshell_pipe[READ], subshell_cwd, MC_MAXPATHLEN + 1);
 538             if (bytes <= 0)
 539             {
 540                 tcsetattr (STDOUT_FILENO, TCSANOW, &shell_mode);
 541                 fprintf (stderr, "read (subshell_pipe[READ]...): %s\r\n",
 542                          unix_error_string (errno));
 543                 exit (EXIT_FAILURE);
 544             }
 545
 546             subshell_cwd[bytes - 1] = 0;        /* Squash the final '\n' */
 547
 548             synchronize ();
 549
 550             subshell_ready = TRUE;
 551             if (subshell_state == RUNNING_COMMAND)
 552             {
 553                 subshell_state = INACTIVE;
 554                 return TRUE;
 555             }
 556         }
 557
 558         else if (FD_ISSET (STDIN_FILENO, &read_set))
 559             /* Read from stdin, write to the subshell */
 560         {
 561             bytes = read (STDIN_FILENO, pty_buffer, sizeof (pty_buffer));
 562             if (bytes <= 0)
 563             {
 564                 tcsetattr (STDOUT_FILENO, TCSANOW, &shell_mode);
 565                 fprintf (stderr,
 566                          "read (STDIN_FILENO, pty_buffer...): %s\r\n", unix_error_string (errno));
 567                 exit (EXIT_FAILURE);
 568             }
 569
 570             for (i = 0; i < bytes; ++i)
 571                 if (pty_buffer[i] == subshell_switch_key)
 572                 {
 573                     write_all (mc_global.tty.subshell_pty, pty_buffer, i);
 574                     if (subshell_ready)
 575                         subshell_state = INACTIVE;
 576                     return TRUE;
 577                 }
 578
 579             write_all (mc_global.tty.subshell_pty, pty_buffer, bytes);
 580
 581             if (pty_buffer[bytes - 1] == '\n' || pty_buffer[bytes - 1] == '\r')
 582                 subshell_ready = FALSE;
 583         }
 584         else
 585             return FALSE;
 586     }
 587 }
 588
 589 /* --------------------------------------------------------------------------------------------- */
 590 /* pty opening functions */
 591
 592 #ifdef HAVE_GRANTPT
 593
 594 /* System V version of pty_open_master */
 595
 596 static int
 597 pty_open_master (char *pty_name)
 598 {
 599     char *slave_name;
 600     int pty_master;
 601
 602 #ifdef HAVE_POSIX_OPENPT
 603     pty_master = posix_openpt (O_RDWR);
 604 #elif HAVE_GETPT
 605     /* getpt () is a GNU extension (glibc 2.1.x) */
 606     pty_master = getpt ();
 607 #elif IS_AIX
 608     strcpy (pty_name, "/dev/ptc");
 609     pty_master = open (pty_name, O_RDWR);
 610 #else
 611     strcpy (pty_name, "/dev/ptmx");
 612     pty_master = open (pty_name, O_RDWR);
 613 #endif
 614
 615     if (pty_master == -1)
 616         return -1;
 617
 618     if (grantpt (pty_master) == -1      /* Grant access to slave */
 619         || unlockpt (pty_master) == -1  /* Clear slave's lock flag */
 620         || !(slave_name = ptsname (pty_master)))        /* Get slave's name */
 621     {
 622         close (pty_master);
 623         return -1;
 624     }
 625     strcpy (pty_name, slave_name);
 626     return pty_master;
 627 }
 628
 629 /* --------------------------------------------------------------------------------------------- */
 630 /** System V version of pty_open_slave */
 631
 632 static int
 633 pty_open_slave (const char *pty_name)
 634 {
 635     int pty_slave = open (pty_name, O_RDWR);
 636
 637     if (pty_slave == -1)
 638     {
 639         fprintf (stderr, "open (%s, O_RDWR): %s\r\n", pty_name, unix_error_string (errno));
 640         return -1;
 641     }
 642 #if !defined(__osf__) && !defined(__linux__)
 643 #if defined (I_FIND) && defined (I_PUSH)
 644     if (!ioctl (pty_slave, I_FIND, "ptem"))
 645         if (ioctl (pty_slave, I_PUSH, "ptem") == -1)
 646         {
 647             fprintf (stderr, "ioctl (%d, I_PUSH, \"ptem\") failed: %s\r\n",
 648                      pty_slave, unix_error_string (errno));
 649             close (pty_slave);
 650             return -1;
 651         }
 652
 653     if (!ioctl (pty_slave, I_FIND, "ldterm"))
 654         if (ioctl (pty_slave, I_PUSH, "ldterm") == -1)
 655         {
 656             fprintf (stderr,
 657                      "ioctl (%d, I_PUSH, \"ldterm\") failed: %s\r\n",
 658                      pty_slave, unix_error_string (errno));
 659             close (pty_slave);
 660             return -1;
 661         }
 662 #if !defined(sgi) && !defined(__sgi)
 663     if (!ioctl (pty_slave, I_FIND, "ttcompat"))
 664         if (ioctl (pty_slave, I_PUSH, "ttcompat") == -1)
 665         {
 666             fprintf (stderr,
 667                      "ioctl (%d, I_PUSH, \"ttcompat\") failed: %s\r\n",
 668                      pty_slave, unix_error_string (errno));
 669             close (pty_slave);
 670             return -1;
 671         }
 672 #endif /* sgi || __sgi */
 673 #endif /* I_FIND && I_PUSH */
 674 #endif /* __osf__ || __linux__ */
 675
 676     fcntl (pty_slave, F_SETFD, FD_CLOEXEC);
 677     return pty_slave;
 678 }
 679
 680 #else /* !HAVE_GRANTPT */
 681
 682 /* --------------------------------------------------------------------------------------------- */
 683 /** BSD version of pty_open_master */
 684 static int
 685 pty_open_master (char *pty_name)
 686 {
 687     int pty_master;
 688     const char *ptr1, *ptr2;
 689
 690     strcpy (pty_name, "/dev/ptyXX");
 691     for (ptr1 = "pqrstuvwxyzPQRST"; *ptr1; ++ptr1)
 692     {
 693         pty_name[8] = *ptr1;
 694         for (ptr2 = "0123456789abcdef"; *ptr2 != '\0'; ++ptr2)
 695         {
 696             pty_name[9] = *ptr2;
 697
 698             /* Try to open master */
 699             pty_master = open (pty_name, O_RDWR);
 700             if (pty_master == -1)
 701             {
 702                 if (errno == ENOENT)    /* Different from EIO */
 703                     return -1;  /* Out of pty devices */
 704                 continue;       /* Try next pty device */
 705             }
 706             pty_name[5] = 't';  /* Change "pty" to "tty" */
 707             if (access (pty_name, 6) != 0)
 708             {
 709                 close (pty_master);
 710                 pty_name[5] = 'p';
 711                 continue;
 712             }
 713             return pty_master;
 714         }
 715     }
 716     return -1;                  /* Ran out of pty devices */
 717 }
 718
 719 /* --------------------------------------------------------------------------------------------- */
 720 /** BSD version of pty_open_slave */
 721
 722 static int
 723 pty_open_slave (const char *pty_name)
 724 {
 725     int pty_slave;
 726     struct group *group_info = getgrnam ("tty");
 727
 728     if (group_info != NULL)
 729     {
 730         /* The following two calls will only succeed if we are root */
 731         /* [Commented out while permissions problem is investigated] */
 732         /* chown (pty_name, getuid (), group_info->gr_gid);  FIXME */
 733         /* chmod (pty_name, S_IRUSR | S_IWUSR | S_IWGRP);   FIXME */
 734     }
 735     pty_slave = open (pty_name, O_RDWR);
 736     if (pty_slave == -1)
 737         fprintf (stderr, "open (pty_name, O_RDWR): %s\r\n", pty_name);
 738     fcntl (pty_slave, F_SETFD, FD_CLOEXEC);
 739     return pty_slave;
 740 }
 741 #endif /* !HAVE_GRANTPT */
 742
 743 /* --------------------------------------------------------------------------------------------- */
 744 /*** public functions ****************************************************************************/
 745 /* --------------------------------------------------------------------------------------------- */
 746
 747 /* --------------------------------------------------------------------------------------------- */
 748 /**
 749  *  Fork the subshell, and set up many, many things.
 750  *
 751  *  Possibly modifies the global variables:
 752  *      subshell_type, subshell_alive, subshell_stopped, subshell_pid
 753  *      mc_global.tty.use_subshell - Is set to FALSE if we can't run the subshell
 754  *      quit - Can be set to SUBSHELL_EXIT by the SIGCHLD handler
 755  */
 756
 757 void
 758 init_subshell (void)
 759 {
 760     /* This must be remembered across calls to init_subshell() */
 761     static char pty_name[BUF_SMALL];
 762     char precmd[BUF_MEDIUM];
 763
 764     switch (check_sid ())
 765     {
 766     case 1:
 767         mc_global.tty.use_subshell = FALSE;
 768         return;
 769     case 2:
 770         mc_global.tty.use_subshell = FALSE;
 771         mc_global.midnight_shutdown = TRUE;
 772         return;
 773     }
 774
 775     /* Take the current (hopefully pristine) tty mode and make */
 776     /* a raw mode based on it now, before we do anything else with it */
 777     init_raw_mode ();
 778
 779     if (mc_global.tty.subshell_pty == 0)
 780     {                           /* First time through */
 781         /* Find out what type of shell we have */
 782
 783         if (strstr (mc_global.tty.shell, "/zsh") || getenv ("ZSH_VERSION"))
 784             subshell_type = ZSH;
 785         else if (strstr (mc_global.tty.shell, "/tcsh"))
 786             subshell_type = TCSH;
 787         else if (strstr (mc_global.tty.shell, "/csh"))
 788             subshell_type = TCSH;
 789         else if (strstr (mc_global.tty.shell, "/bash") || getenv ("BASH"))
 790             subshell_type = BASH;
 791         else if (strstr (mc_global.tty.shell, "/fish"))
 792             subshell_type = FISH;
 793         else
 794         {
 795             mc_global.tty.use_subshell = FALSE;
 796             return;
 797         }
 798
 799         /* Open a pty for talking to the subshell */
 800
 801         /* FIXME: We may need to open a fresh pty each time on SVR4 */
 802
 803         mc_global.tty.subshell_pty = pty_open_master (pty_name);
 804         if (mc_global.tty.subshell_pty == -1)
 805         {
 806             fprintf (stderr, "Cannot open master side of pty: %s\r\n", unix_error_string (errno));
 807             mc_global.tty.use_subshell = FALSE;
 808             return;
 809         }
 810         subshell_pty_slave = pty_open_slave (pty_name);
 811         if (subshell_pty_slave == -1)
 812         {
 813             fprintf (stderr, "Cannot open slave side of pty %s: %s\r\n",
 814                      pty_name, unix_error_string (errno));
 815             mc_global.tty.use_subshell = FALSE;
 816             return;
 817         }
 818
 819         /* Create a pipe for receiving the subshell's CWD */
 820
 821         if (subshell_type == TCSH)
 822         {
 823             g_snprintf (tcsh_fifo, sizeof (tcsh_fifo), "%s/mc.pipe.%d",
 824                         mc_tmpdir (), (int) getpid ());
 825             if (mkfifo (tcsh_fifo, 0600) == -1)
 826             {
 827                 fprintf (stderr, "mkfifo(%s) failed: %s\r\n", tcsh_fifo, unix_error_string (errno));
 828                 mc_global.tty.use_subshell = FALSE;
 829                 return;
 830             }
 831
 832             /* Opening the FIFO as O_RDONLY or O_WRONLY causes deadlock */
 833
 834             if ((subshell_pipe[READ] = open (tcsh_fifo, O_RDWR)) == -1
 835                 || (subshell_pipe[WRITE] = open (tcsh_fifo, O_RDWR)) == -1)
 836             {
 837                 fprintf (stderr, _("Cannot open named pipe %s\n"), tcsh_fifo);
 838                 perror (__FILE__ ": open");
 839                 mc_global.tty.use_subshell = FALSE;
 840                 return;
 841             }
 842         }
 843         else /* subshell_type is BASH or ZSH */ if (pipe (subshell_pipe))
 844         {
 845             perror (__FILE__ ": couldn't create pipe");
 846             mc_global.tty.use_subshell = FALSE;
 847             return;
 848         }
 849     }
 850
 851     /* Fork the subshell */
 852
 853     subshell_alive = TRUE;
 854     subshell_stopped = FALSE;
 855     subshell_pid = fork ();
 856
 857     if (subshell_pid == -1)
 858     {
 859         fprintf (stderr, "Cannot spawn the subshell process: %s\r\n", unix_error_string (errno));
 860         /* We exit here because, if the process table is full, the */
 861         /* other method of running user commands won't work either */
 862         exit (EXIT_FAILURE);
 863     }
 864
 865     if (subshell_pid == 0)
 866     {
 867         /* We are in the child process */
 868         init_subshell_child (pty_name);
 869     }
 870
 871     /* Set up 'precmd' or equivalent for reading the subshell's CWD */
 872
 873     switch (subshell_type)
 874     {
 875     case BASH:
 876         g_snprintf (precmd, sizeof (precmd),
 877                     " PROMPT_COMMAND=${PROMPT_COMMAND:+$PROMPT_COMMAND; }'pwd>&%d;kill -STOP $$'\n",
 878                     subshell_pipe[WRITE]);
 879         break;
 880
 881     case ZSH:
 882         g_snprintf (precmd, sizeof (precmd),
 883                     " _mc_precmd(){ pwd>&%d;kill -STOP $$ }; precmd_functions+=(_mc_precmd)\n",
 884                     subshell_pipe[WRITE]);
 885         break;
 886
 887     case TCSH:
 888         g_snprintf (precmd, sizeof (precmd),
 889                     "set echo_style=both;"
 890                     "alias precmd 'echo $cwd:q >>%s;kill -STOP $$'\n", tcsh_fifo);
 891         break;
 892     case FISH:
 893         /* Use fish_prompt_mc function for prompt, if not present then copy fish_prompt to it. */
 894         g_snprintf (precmd, sizeof (precmd),
 895                     "if not functions -q fish_prompt_mc;"
 896                     "functions -c fish_prompt fish_prompt_mc; end;"
 897                     "function fish_prompt; echo $PWD>&%d; fish_prompt_mc; kill -STOP %%self; end\n",
 898                     subshell_pipe[WRITE]);
 899         break;
 900
 901     }
 902     write_all (mc_global.tty.subshell_pty, precmd, strlen (precmd));
 903
 904     /* Wait until the subshell has started up and processed the command */
 905
 906     subshell_state = RUNNING_COMMAND;
 907     tty_enable_interrupt_key ();
 908     if (!feed_subshell (QUIETLY, TRUE))
 909     {
 910         mc_global.tty.use_subshell = FALSE;
 911     }
 912     tty_disable_interrupt_key ();
 913     if (!subshell_alive)
 914         mc_global.tty.use_subshell = FALSE;     /* Subshell died instantly, so don't use it */
 915 }
 916
 917 /* --------------------------------------------------------------------------------------------- */
 918
 919 int
 920 invoke_subshell (const char *command, int how, vfs_path_t ** new_dir_vpath)
 921 {
 922     /* Make the MC terminal transparent */
 923     tcsetattr (STDOUT_FILENO, TCSANOW, &raw_mode);
 924
 925     /* Make the subshell change to MC's working directory */
 926     if (new_dir_vpath != NULL)
 927         do_subshell_chdir (current_panel->cwd_vpath, TRUE);
 928
 929     if (command == NULL)        /* The user has done "C-o" from MC */
 930     {
 931         if (subshell_state == INACTIVE)
 932         {
 933             subshell_state = ACTIVE;
 934             /* FIXME: possibly take out this hack; the user can
 935                re-play it by hitting C-hyphen a few times! */
 936             if (subshell_ready)
 937                 write_all (mc_global.tty.subshell_pty, " \b", 2);       /* Hack to make prompt reappear */
 938         }
 939     }
 940     else                        /* MC has passed us a user command */
 941     {
 942         if (how == QUIETLY)
 943             write_all (mc_global.tty.subshell_pty, " ", 1);
 944         /* FIXME: if command is long (>8KB ?) we go comma */
 945         write_all (mc_global.tty.subshell_pty, command, strlen (command));
 946         write_all (mc_global.tty.subshell_pty, "\n", 1);
 947         subshell_state = RUNNING_COMMAND;
 948         subshell_ready = FALSE;
 949     }
 950
 951     feed_subshell (how, FALSE);
 952
 953     if (new_dir_vpath != NULL && subshell_alive)
 954     {
 955         const char *pcwd;
 956
 957         pcwd = vfs_translate_path (vfs_path_as_str (current_panel->cwd_vpath));
 958         if (strcmp (subshell_cwd, pcwd) != 0)
 959             *new_dir_vpath = vfs_path_from_str (subshell_cwd);  /* Make MC change to the subshell's CWD */
 960     }
 961
 962     /* Restart the subshell if it has died by SIGHUP, SIGQUIT, etc. */
 963     while (!subshell_alive && quit == 0 && mc_global.tty.use_subshell)
 964         init_subshell ();
 965
 966     return quit;
 967 }
 968
 969
 970 /* --------------------------------------------------------------------------------------------- */
 971
 972 gboolean
 973 read_subshell_prompt (void)
 974 {
 975     int rc = 0;
 976     ssize_t bytes = 0;
 977     struct timeval timeleft = { 0, 0 };
 978     GString *p;
 979     gboolean prompt_was_reset = FALSE;
 980
 981     fd_set tmp;
 982     FD_ZERO (&tmp);
 983     FD_SET (mc_global.tty.subshell_pty, &tmp);
 984
 985     /* First time through */
 986     if (subshell_prompt == NULL)
 987         subshell_prompt = g_string_sized_new (INITIAL_PROMPT_SIZE);
 988
 989     p = g_string_sized_new (INITIAL_PROMPT_SIZE);
 990
 991     while (subshell_alive
 992            && (rc = select (mc_global.tty.subshell_pty + 1, &tmp, NULL, NULL, &timeleft)) != 0)
 993     {
 994         ssize_t i;
 995
 996         /* Check for 'select' errors */
 997         if (rc == -1)
 998         {
 999             if (errno == EINTR)
1000             {
1001                 if (mc_global.tty.winch_flag != 0)
1002                     tty_change_screen_size ();
1003
1004                 continue;
1005             }
1006
1007             fprintf (stderr, "select (FD_SETSIZE, &tmp...): %s\r\n", unix_error_string (errno));
1008             exit (EXIT_FAILURE);
1009         }
1010
1011         bytes = read (mc_global.tty.subshell_pty, pty_buffer, sizeof (pty_buffer));
1012
1013         /* Extract the prompt from the shell output */
1014         for (i = 0; i < bytes; i++)
1015             if (pty_buffer[i] == '\n' || pty_buffer[i] == '\r')
1016             {
1017                 g_string_set_size (p, 0);
1018                 prompt_was_reset = TRUE;
1019             }
1020             else if (pty_buffer[i] != '\0')
1021                 g_string_append_c (p, pty_buffer[i]);
1022     }
1023
1024     if (p->len != 0 || prompt_was_reset)
1025         g_string_assign (subshell_prompt, p->str);
1026
1027     g_string_free (p, TRUE);
1028
1029     return (rc != 0 || bytes != 0);
1030 }
1031
1032 /* --------------------------------------------------------------------------------------------- */
1033
1034 void
1035 do_update_prompt (void)
1036 {
1037     if (update_subshell_prompt)
1038     {
1039         printf ("\r\n%s", subshell_prompt->str);
1040         fflush (stdout);
1041         update_subshell_prompt = FALSE;
1042     }
1043 }
1044
1045 /* --------------------------------------------------------------------------------------------- */
1046
1047 gboolean
1048 exit_subshell (void)
1049 {
1050     gboolean subshell_quit = TRUE;
1051
1052     if (subshell_state != INACTIVE && subshell_alive)
1053         subshell_quit =
1054             query_dialog (_("Warning"),
1055                           _("The shell is still active. Quit anyway?"),
1056                           D_NORMAL, 2, _("&Yes"), _("&No")) == 0;
1057
1058     if (subshell_quit)
1059     {
1060         if (subshell_type == TCSH)
1061         {
1062             if (unlink (tcsh_fifo) == -1)
1063                 fprintf (stderr, "Cannot remove named pipe %s: %s\r\n",
1064                          tcsh_fifo, unix_error_string (errno));
1065         }
1066
1067         g_string_free (subshell_prompt, TRUE);
1068         subshell_prompt = NULL;
1069         pty_buffer[0] = '\0';
1070     }
1071
1072     return subshell_quit;
1073 }
1074
1075 /* --------------------------------------------------------------------------------------------- */
1076 /**
1077  * Carefully quote directory name to allow entering any directory safely,
1078  * no matter what weird characters it may contain in its name.
1079  * NOTE: Treat directory name an untrusted data, don't allow it to cause
1080  * executing any commands in the shell.  Escape all control characters.
1081  * Use following technique:
1082  *
1083  * printf(1) with format string containing a single conversion specifier,
1084  * "b", and an argument which contains a copy of the string passed to
1085  * subshell_name_quote() with all characters, except digits and letters,
1086  * replaced by the backslash-escape sequence \0nnn, where "nnn" is the
1087  * numeric value of the character converted to octal number.
1088  *
1089  *   cd "`printf "%b" 'ABC\0nnnDEF\0nnnXYZ'`"
1090  *
1091  */
1092
1093 static GString *
1094 subshell_name_quote (const char *s)
1095 {
1096     GString *ret;
1097     const char *su, *n;
1098     const char *quote_cmd_start, *quote_cmd_end;
1099
1100     if (subshell_type == FISH)
1101     {
1102         quote_cmd_start = "(printf \"%b\" '";
1103         quote_cmd_end = "')";
1104     }
1105     else
1106     {
1107         quote_cmd_start = "\"`printf \"%b\" '";
1108         quote_cmd_end = "'`\"";
1109     }
1110
1111     ret = g_string_sized_new (64);
1112
1113     /* Prevent interpreting leading '-' as a switch for 'cd' */
1114     if (s[0] == '-')
1115         g_string_append (ret, "./");
1116
1117     /* Copy the beginning of the command to the buffer */
1118     g_string_append (ret, quote_cmd_start);
1119
1120     /*
1121      * Print every character except digits and letters as a backslash-escape
1122      * sequence of the form \0nnn, where "nnn" is the numeric value of the
1123      * character converted to octal number.
1124      */
1125     for (su = s; su[0] != '\0'; su = n)
1126     {
1127         n = str_cget_next_char_safe (su);
1128
1129         if (str_isalnum (su))
1130             g_string_append_len (ret, su, n - su);
1131         else
1132         {
1133             int c;
1134
1135             for (c = 0; c < n - su; c++)
1136                 g_string_append_printf (ret, "\\0%03o", (unsigned char) su[c]);
1137         }
1138     }
1139
1140     g_string_append (ret, quote_cmd_end);
1141
1142     return ret;
1143 }
1144
1145
1146 /* --------------------------------------------------------------------------------------------- */
1147
1148 /** If it actually changed the directory it returns true */
1149 void
1150 do_subshell_chdir (const vfs_path_t * vpath, gboolean update_prompt)
1151 {
1152     char *pcwd;
1153
1154     pcwd = vfs_path_to_str_flags (current_panel->cwd_vpath, 0, VPF_RECODE);
1155
1156     if (!(subshell_state == INACTIVE && strcmp (subshell_cwd, pcwd) != 0))
1157     {
1158         /* We have to repaint the subshell prompt if we read it from
1159          * the main program.  Please note that in the code after this
1160          * if, the cd command that is sent will make the subshell
1161          * repaint the prompt, so we don't have to paint it. */
1162         if (update_prompt)
1163             do_update_prompt ();
1164         g_free (pcwd);
1165         return;
1166     }
1167
1168     /* The initial space keeps this out of the command history (in bash
1169        because we set "HISTCONTROL=ignorespace") */
1170     write_all (mc_global.tty.subshell_pty, " cd ", 4);
1171
1172     if (vpath != NULL)
1173     {
1174         const char *translate;
1175
1176         translate = vfs_translate_path (vfs_path_as_str (vpath));
1177         if (translate != NULL)
1178         {
1179             GString *temp;
1180
1181             temp = subshell_name_quote (translate);
1182             write_all (mc_global.tty.subshell_pty, temp->str, temp->len);
1183             g_string_free (temp, TRUE);
1184         }
1185         else
1186         {
1187             write_all (mc_global.tty.subshell_pty, ".", 1);
1188         }
1189     }
1190     else
1191     {
1192         write_all (mc_global.tty.subshell_pty, "/", 1);
1193     }
1194     write_all (mc_global.tty.subshell_pty, "\n", 1);
1195
1196     subshell_state = RUNNING_COMMAND;
1197     feed_subshell (QUIETLY, FALSE);
1198
1199     if (subshell_alive)
1200     {
1201         int bPathNotEq = strcmp (subshell_cwd, pcwd);
1202
1203         if (bPathNotEq && subshell_type == TCSH)
1204         {
1205             char rp_subshell_cwd[PATH_MAX];
1206             char rp_current_panel_cwd[PATH_MAX];
1207
1208             char *p_subshell_cwd = mc_realpath (subshell_cwd, rp_subshell_cwd);
1209             char *p_current_panel_cwd = mc_realpath (pcwd, rp_current_panel_cwd);
1210
1211             if (p_subshell_cwd == NULL)
1212                 p_subshell_cwd = subshell_cwd;
1213             if (p_current_panel_cwd == NULL)
1214                 p_current_panel_cwd = pcwd;
1215             bPathNotEq = strcmp (p_subshell_cwd, p_current_panel_cwd);
1216         }
1217
1218         if (bPathNotEq && !DIR_IS_DOT (pcwd))
1219         {
1220             char *cwd;
1221
1222             cwd = vfs_path_to_str_flags (current_panel->cwd_vpath, 0, VPF_STRIP_PASSWORD);
1223             vfs_print_message (_("Warning: Cannot change to %s.\n"), cwd);
1224             g_free (cwd);
1225         }
1226     }
1227
1228     /* Really escape Zsh history */
1229     if (subshell_type == ZSH)
1230     {
1231         /* Per Zsh documentation last command prefixed with space lingers in the internal history
1232          * until the next command is entered before it vanishes. To make it vanish right away,
1233          * type a space and press return. */
1234         write_all (mc_global.tty.subshell_pty, " \n", 2);
1235         subshell_state = RUNNING_COMMAND;
1236         feed_subshell (QUIETLY, FALSE);
1237     }
1238
1239     update_subshell_prompt = FALSE;
1240
1241     g_free (pcwd);
1242     /* Make sure that MC never stores the CWD in a silly format */
1243     /* like /usr////lib/../bin, or the strcmp() above will fail */
1244 }
1245
1246 /* --------------------------------------------------------------------------------------------- */
1247
1248 void
1249 subshell_get_console_attributes (void)
1250 {
1251     /* Get our current terminal modes */
1252
1253     if (tcgetattr (STDOUT_FILENO, &shell_mode))
1254     {
1255         fprintf (stderr, "Cannot get terminal settings: %s\r\n", unix_error_string (errno));
1256         mc_global.tty.use_subshell = FALSE;
1257     }
1258 }
1259
1260 /* --------------------------------------------------------------------------------------------- */
1261 /**
1262  * Figure out whether the subshell has stopped, exited or been killed
1263  * Possibly modifies: 'subshell_alive', 'subshell_stopped' and 'quit' */
1264
1265 void
1266 sigchld_handler (int sig)
1267 {
1268     int status;
1269     pid_t pid;
1270
1271     (void) sig;
1272
1273     pid = waitpid (subshell_pid, &status, WUNTRACED | WNOHANG);
1274
1275     if (pid == subshell_pid)
1276     {
1277         /* Figure out what has happened to the subshell */
1278
1279         if (WIFSTOPPED (status))
1280         {
1281             if (WSTOPSIG (status) == SIGSTOP)
1282             {
1283                 /* The subshell has received a SIGSTOP signal */
1284                 subshell_stopped = TRUE;
1285             }
1286             else
1287             {
1288                 /* The user has suspended the subshell.  Revive it */
1289                 kill (subshell_pid, SIGCONT);
1290             }
1291         }
1292         else
1293         {
1294             /* The subshell has either exited normally or been killed */
1295             subshell_alive = FALSE;
1296             delete_select_channel (mc_global.tty.subshell_pty);
1297             if (WIFEXITED (status) && WEXITSTATUS (status) != FORK_FAILURE)
1298                 quit |= SUBSHELL_EXIT;  /* Exited normally */
1299         }
1300     }
1301 #ifdef __linux__
1302     pid = waitpid (cons_saver_pid, &status, WUNTRACED | WNOHANG);
1303
1304     if (pid == cons_saver_pid)
1305     {
1306
1307         if (WIFSTOPPED (status))
1308             /* Someone has stopped cons.saver - restart it */
1309             kill (pid, SIGCONT);
1310         else
1311         {
1312             /* cons.saver has died - disable confole saving */
1313             handle_console (CONSOLE_DONE);
1314             mc_global.tty.console_flag = '\0';
1315         }
1316
1317     }
1318 #endif /* __linux__ */
1319
1320     /* If we got here, some other child exited; ignore it */
1321 }
1322
1323 /* --------------------------------------------------------------------------------------------- */