gdb/inflow.c

   1 /* Low level interface to ptrace, for GDB when running under Unix.
   2    Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
   3    1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
   4    2009 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "frame.h"
  23 #include "inferior.h"
  24 #include "command.h"
  25 #include "serial.h"
  26 #include "terminal.h"
  27 #include "target.h"
  28 #include "gdbthread.h"
  29 #include "observer.h"
  30
  31 #include "gdb_string.h"
  32 #include <signal.h>
  33 #include <fcntl.h>
  34 #include "gdb_select.h"
  35
  36 #include "inflow.h"
  37
  38 #ifdef HAVE_SYS_IOCTL_H
  39 #include <sys/ioctl.h>
  40 #endif
  41
  42 #ifndef O_NOCTTY
  43 #define O_NOCTTY 0
  44 #endif
  45
  46 #if defined (SIGIO) && defined (FASYNC) && defined (FD_SET) && defined (F_SETOWN)
  47 static void handle_sigio (int);
  48 #endif
  49
  50 extern void _initialize_inflow (void);
  51
  52 static void pass_signal (int);
  53
  54 static void kill_command (char *, int);
  55
  56 static void terminal_ours_1 (int);
  57 \f
  58 /* Record terminal status separately for debugger and inferior.  */
  59
  60 static struct serial *stdin_serial;
  61
  62 /* Terminal related info we need to keep track of.  Each inferior
  63    holds an instance of this structure --- we save it whenever the
  64    corresponding inferior stops, and restore it to the foreground
  65    inferior when it resumes.  */
  66 struct terminal_info
  67 {
  68   /* The name of the tty (from the `tty' command) that we gave to the
  69      inferior when it was started.  */
  70   const char *run_terminal;
  71
  72   /* TTY state.  We save it whenever the inferior stops, and restore
  73      it when it resumes.  */
  74   serial_ttystate ttystate;
  75
  76 #ifdef PROCESS_GROUP_TYPE
  77   /* Process group.  Saved and restored just like ttystate.  */
  78   PROCESS_GROUP_TYPE process_group;
  79 #endif
  80
  81   /* fcntl flags.  Saved and restored just like ttystate.  */
  82   int tflags;
  83 };
  84
  85 /* Our own tty state, which we restore every time we need to deal with
  86    the terminal.  This is only set once, when GDB first starts.  The
  87    settings of flags which readline saves and restores and
  88    unimportant.  */
  89 static struct terminal_info our_terminal_info;
  90
  91 #ifdef PROCESS_GROUP_TYPE
  92
  93 /* Return the process group of the current inferior.  */
  94
  95 PROCESS_GROUP_TYPE
  96 inferior_process_group (void)
  97 {
  98   return current_inferior ()->terminal_info->process_group;
  99 }
 100 #endif
 101
 102 /* While the inferior is running, we want SIGINT and SIGQUIT to go to the
 103    inferior only.  If we have job control, that takes care of it.  If not,
 104    we save our handlers in these two variables and set SIGINT and SIGQUIT
 105    to SIG_IGN.  */
 106
 107 static void (*sigint_ours) ();
 108 static void (*sigquit_ours) ();
 109
 110 /* The name of the tty (from the `tty' command) that we're giving to
 111    the inferior when starting it up.  This is only (and should only
 112    be) used as a transient global by new_tty_prefork, new_tty and
 113    create_tty_session, called from fork_inferior, while forking a new
 114    child.  */
 115 static const char *inferior_thisrun_terminal;
 116
 117 /* Nonzero if our terminal settings are in effect.  Zero if the
 118    inferior's settings are in effect.  Ignored if !gdb_has_a_terminal
 119    ().  */
 120
 121 int terminal_is_ours;
 122
 123 #ifdef PROCESS_GROUP_TYPE
 124 static PROCESS_GROUP_TYPE
 125 gdb_getpgrp (void)
 126 {
 127   int process_group = -1;
 128 #ifdef HAVE_TERMIOS
 129   process_group = tcgetpgrp (0);
 130 #endif
 131 #ifdef HAVE_TERMIO
 132   process_group = getpgrp ();
 133 #endif
 134 #ifdef HAVE_SGTTY
 135   ioctl (0, TIOCGPGRP, &process_group);
 136 #endif
 137   return process_group;
 138 }
 139 #endif
 140
 141 enum
 142   {
 143     yes, no, have_not_checked
 144   }
 145 gdb_has_a_terminal_flag = have_not_checked;
 146
 147 /* Does GDB have a terminal (on stdin)?  */
 148 int
 149 gdb_has_a_terminal (void)
 150 {
 151   switch (gdb_has_a_terminal_flag)
 152     {
 153     case yes:
 154       return 1;
 155     case no:
 156       return 0;
 157     case have_not_checked:
 158       /* Get all the current tty settings (including whether we have a
 159          tty at all!).  Can't do this in _initialize_inflow because
 160          serial_fdopen() won't work until the serial_ops_list is
 161          initialized.  */
 162
 163 #ifdef F_GETFL
 164       our_terminal_info.tflags = fcntl (0, F_GETFL, 0);
 165 #endif
 166
 167       gdb_has_a_terminal_flag = no;
 168       if (stdin_serial != NULL)
 169         {
 170           our_terminal_info.ttystate = serial_get_tty_state (stdin_serial);
 171
 172           if (our_terminal_info.ttystate != NULL)
 173             {
 174               gdb_has_a_terminal_flag = yes;
 175 #ifdef PROCESS_GROUP_TYPE
 176               our_terminal_info.process_group = gdb_getpgrp ();
 177 #endif
 178             }
 179         }
 180
 181       return gdb_has_a_terminal_flag == yes;
 182     default:
 183       /* "Can't happen".  */
 184       return 0;
 185     }
 186 }
 187
 188 /* Macro for printing errors from ioctl operations */
 189
 190 #define OOPSY(what)     \
 191   if (result == -1)     \
 192     fprintf_unfiltered(gdb_stderr, "[%s failed in terminal_inferior: %s]\n", \
 193             what, safe_strerror (errno))
 194
 195 static void terminal_ours_1 (int);
 196
 197 /* Initialize the terminal settings we record for the inferior,
 198    before we actually run the inferior.  */
 199
 200 void
 201 terminal_init_inferior_with_pgrp (int pgrp)
 202 {
 203   if (gdb_has_a_terminal ())
 204     {
 205       struct inferior *inf = current_inferior ();
 206
 207       /* We could just as well copy our_ttystate (if we felt like
 208          adding a new function serial_copy_tty_state()).  */
 209       xfree (inf->terminal_info->ttystate);
 210       inf->terminal_info->ttystate
 211         = serial_get_tty_state (stdin_serial);
 212
 213 #ifdef PROCESS_GROUP_TYPE
 214       inf->terminal_info->process_group = pgrp;
 215 #endif
 216
 217       /* Make sure that next time we call terminal_inferior (which will be
 218          before the program runs, as it needs to be), we install the new
 219          process group.  */
 220       terminal_is_ours = 1;
 221     }
 222 }
 223
 224 /* Save the terminal settings again.  This is necessary for the TUI
 225    when it switches to TUI or non-TUI mode;  curses changes the terminal
 226    and gdb must be able to restore it correctly.  */
 227
 228 void
 229 terminal_save_ours (void)
 230 {
 231   if (gdb_has_a_terminal ())
 232     {
 233       /* We could just as well copy our_ttystate (if we felt like adding
 234          a new function serial_copy_tty_state).  */
 235       xfree (our_terminal_info.ttystate);
 236       our_terminal_info.ttystate = serial_get_tty_state (stdin_serial);
 237     }
 238 }
 239
 240 void
 241 terminal_init_inferior (void)
 242 {
 243 #ifdef PROCESS_GROUP_TYPE
 244   /* This is for Lynx, and should be cleaned up by having Lynx be a separate
 245      debugging target with a version of target_terminal_init_inferior which
 246      passes in the process group to a generic routine which does all the work
 247      (and the non-threaded child_terminal_init_inferior can just pass in
 248      inferior_ptid to the same routine).  */
 249   /* We assume INFERIOR_PID is also the child's process group.  */
 250   terminal_init_inferior_with_pgrp (PIDGET (inferior_ptid));
 251 #endif /* PROCESS_GROUP_TYPE */
 252 }
 253
 254 /* Put the inferior's terminal settings into effect.
 255    This is preparation for starting or resuming the inferior.  */
 256
 257 void
 258 terminal_inferior (void)
 259 {
 260   struct inferior *inf;
 261
 262   if (!terminal_is_ours)
 263     return;
 264
 265   inf = current_inferior ();
 266
 267   if (gdb_has_a_terminal ()
 268       && inf->terminal_info->ttystate != NULL
 269       && inf->terminal_info->run_terminal == NULL)
 270     {
 271       int result;
 272
 273 #ifdef F_GETFL
 274       /* Is there a reason this is being done twice?  It happens both
 275          places we use F_SETFL, so I'm inclined to think perhaps there
 276          is some reason, however perverse.  Perhaps not though...  */
 277       result = fcntl (0, F_SETFL, inf->terminal_info->tflags);
 278       result = fcntl (0, F_SETFL, inf->terminal_info->tflags);
 279       OOPSY ("fcntl F_SETFL");
 280 #endif
 281
 282       /* Because we were careful to not change in or out of raw mode in
 283          terminal_ours, we will not change in our out of raw mode with
 284          this call, so we don't flush any input.  */
 285       result = serial_set_tty_state (stdin_serial,
 286                                      inf->terminal_info->ttystate);
 287       OOPSY ("setting tty state");
 288
 289       if (!job_control)
 290         {
 291           sigint_ours = (void (*)()) signal (SIGINT, SIG_IGN);
 292 #ifdef SIGQUIT
 293           sigquit_ours = (void (*)()) signal (SIGQUIT, SIG_IGN);
 294 #endif
 295         }
 296
 297       /* If attach_flag is set, we don't know whether we are sharing a
 298          terminal with the inferior or not.  (attaching a process
 299          without a terminal is one case where we do not; attaching a
 300          process which we ran from the same shell as GDB via `&' is
 301          one case where we do, I think (but perhaps this is not
 302          `sharing' in the sense that we need to save and restore tty
 303          state)).  I don't know if there is any way to tell whether we
 304          are sharing a terminal.  So what we do is to go through all
 305          the saving and restoring of the tty state, but ignore errors
 306          setting the process group, which will happen if we are not
 307          sharing a terminal).  */
 308
 309       if (job_control)
 310         {
 311 #ifdef HAVE_TERMIOS
 312           result = tcsetpgrp (0, inf->terminal_info->process_group);
 313           if (!inf->attach_flag)
 314             OOPSY ("tcsetpgrp");
 315 #endif
 316
 317 #ifdef HAVE_SGTTY
 318           result = ioctl (0, TIOCSPGRP, &inf->terminal_info->process_group);
 319           if (!inf->attach_flag)
 320             OOPSY ("TIOCSPGRP");
 321 #endif
 322         }
 323
 324     }
 325   terminal_is_ours = 0;
 326 }
 327
 328 /* Put some of our terminal settings into effect,
 329    enough to get proper results from our output,
 330    but do not change into or out of RAW mode
 331    so that no input is discarded.
 332
 333    After doing this, either terminal_ours or terminal_inferior
 334    should be called to get back to a normal state of affairs.  */
 335
 336 void
 337 terminal_ours_for_output (void)
 338 {
 339   terminal_ours_1 (1);
 340 }
 341
 342 /* Put our terminal settings into effect.
 343    First record the inferior's terminal settings
 344    so they can be restored properly later.  */
 345
 346 void
 347 terminal_ours (void)
 348 {
 349   terminal_ours_1 (0);
 350 }
 351
 352 /* output_only is not used, and should not be used unless we introduce
 353    separate terminal_is_ours and terminal_is_ours_for_output
 354    flags.  */
 355
 356 static void
 357 terminal_ours_1 (int output_only)
 358 {
 359   struct inferior *inf;
 360
 361   if (terminal_is_ours)
 362     return;
 363
 364   /* Checking inferior->run_terminal is necessary so that
 365      if GDB is running in the background, it won't block trying
 366      to do the ioctl()'s below.  Checking gdb_has_a_terminal
 367      avoids attempting all the ioctl's when running in batch.  */
 368
 369   inf = current_inferior ();
 370
 371   if (inf->terminal_info->run_terminal != NULL || gdb_has_a_terminal () == 0)
 372     return;
 373
 374   if (!terminal_is_ours)
 375     {
 376 #ifdef SIGTTOU
 377       /* Ignore this signal since it will happen when we try to set the
 378          pgrp.  */
 379       void (*osigttou) () = NULL;
 380 #endif
 381       int result;
 382
 383       terminal_is_ours = 1;
 384
 385 #ifdef SIGTTOU
 386       if (job_control)
 387         osigttou = (void (*)()) signal (SIGTTOU, SIG_IGN);
 388 #endif
 389
 390       xfree (inf->terminal_info->ttystate);
 391       inf->terminal_info->ttystate = serial_get_tty_state (stdin_serial);
 392
 393 #ifdef PROCESS_GROUP_TYPE
 394       if (!inf->attach_flag)
 395         /* If setpgrp failed in terminal_inferior, this would give us
 396            our process group instead of the inferior's.  See
 397            terminal_inferior for details.  */
 398         inf->terminal_info->process_group = gdb_getpgrp ();
 399 #endif
 400
 401       /* Here we used to set ICANON in our ttystate, but I believe this
 402          was an artifact from before when we used readline.  Readline sets
 403          the tty state when it needs to.
 404          FIXME-maybe: However, query() expects non-raw mode and doesn't
 405          use readline.  Maybe query should use readline (on the other hand,
 406          this only matters for HAVE_SGTTY, not termio or termios, I think).  */
 407
 408       /* Set tty state to our_ttystate.  We don't change in our out of raw
 409          mode, to avoid flushing input.  We need to do the same thing
 410          regardless of output_only, because we don't have separate
 411          terminal_is_ours and terminal_is_ours_for_output flags.  It's OK,
 412          though, since readline will deal with raw mode when/if it needs to.
 413        */
 414
 415       serial_noflush_set_tty_state (stdin_serial, our_terminal_info.ttystate,
 416                                     inf->terminal_info->ttystate);
 417
 418       if (job_control)
 419         {
 420 #ifdef HAVE_TERMIOS
 421           result = tcsetpgrp (0, our_terminal_info.process_group);
 422 #if 0
 423           /* This fails on Ultrix with EINVAL if you run the testsuite
 424              in the background with nohup, and then log out.  GDB never
 425              used to check for an error here, so perhaps there are other
 426              such situations as well.  */
 427           if (result == -1)
 428             fprintf_unfiltered (gdb_stderr, "[tcsetpgrp failed in terminal_ours: %s]\n",
 429                                 safe_strerror (errno));
 430 #endif
 431 #endif /* termios */
 432
 433 #ifdef HAVE_SGTTY
 434           result = ioctl (0, TIOCSPGRP, &our_terminal_info.process_group);
 435 #endif
 436         }
 437
 438 #ifdef SIGTTOU
 439       if (job_control)
 440         signal (SIGTTOU, osigttou);
 441 #endif
 442
 443       if (!job_control)
 444         {
 445           signal (SIGINT, sigint_ours);
 446 #ifdef SIGQUIT
 447           signal (SIGQUIT, sigquit_ours);
 448 #endif
 449         }
 450
 451 #ifdef F_GETFL
 452       inf->terminal_info->tflags = fcntl (0, F_GETFL, 0);
 453
 454       /* Is there a reason this is being done twice?  It happens both
 455          places we use F_SETFL, so I'm inclined to think perhaps there
 456          is some reason, however perverse.  Perhaps not though...  */
 457       result = fcntl (0, F_SETFL, our_terminal_info.tflags);
 458       result = fcntl (0, F_SETFL, our_terminal_info.tflags);
 459 #endif
 460     }
 461 }
 462
 463 /* This is a "new_inferior" observer.  It's business is to allocate
 464    the TERMINAL_INFO member of the inferior structure.  This field is
 465    private to inflow.c, and its type is opaque to the rest of GDB.
 466    PID is the target pid of the inferior that has just been added to
 467    the inferior list.  */
 468
 469 static void
 470 inflow_new_inferior (int pid)
 471 {
 472   struct inferior *inf = find_inferior_pid (pid);
 473
 474   inf->terminal_info = XZALLOC (struct terminal_info);
 475 }
 476
 477 /* This is a "inferior_exit" observer.  Releases the TERMINAL_INFO member
 478    of the inferior structure.  This field is private to inflow.c, and
 479    its type is opaque to the rest of GDB.  PID is the target pid of
 480    the inferior that is about to be removed from the inferior
 481    list.  */
 482
 483 static void
 484 inflow_inferior_exit (int pid)
 485 {
 486   struct inferior *inf = find_inferior_pid (pid);
 487
 488   xfree (inf->terminal_info);
 489   inf->terminal_info = NULL;
 490 }
 491
 492 void
 493 term_info (char *arg, int from_tty)
 494 {
 495   target_terminal_info (arg, from_tty);
 496 }
 497
 498 void
 499 child_terminal_info (char *args, int from_tty)
 500 {
 501   struct inferior *inf;
 502
 503   if (!gdb_has_a_terminal ())
 504     {
 505       printf_filtered (_("This GDB does not control a terminal.\n"));
 506       return;
 507     }
 508
 509   if (ptid_equal (inferior_ptid, null_ptid))
 510     return;
 511
 512   inf = current_inferior ();
 513
 514   printf_filtered (_("Inferior's terminal status (currently saved by GDB):\n"));
 515
 516   /* First the fcntl flags.  */
 517   {
 518     int flags;
 519
 520     flags = inf->terminal_info->tflags;
 521
 522     printf_filtered ("File descriptor flags = ");
 523
 524 #ifndef O_ACCMODE
 525 #define O_ACCMODE (O_RDONLY | O_WRONLY | O_RDWR)
 526 #endif
 527     /* (O_ACCMODE) parens are to avoid Ultrix header file bug */
 528     switch (flags & (O_ACCMODE))
 529       {
 530       case O_RDONLY:
 531         printf_filtered ("O_RDONLY");
 532         break;
 533       case O_WRONLY:
 534         printf_filtered ("O_WRONLY");
 535         break;
 536       case O_RDWR:
 537         printf_filtered ("O_RDWR");
 538         break;
 539       }
 540     flags &= ~(O_ACCMODE);
 541
 542 #ifdef O_NONBLOCK
 543     if (flags & O_NONBLOCK)
 544       printf_filtered (" | O_NONBLOCK");
 545     flags &= ~O_NONBLOCK;
 546 #endif
 547
 548 #if defined (O_NDELAY)
 549     /* If O_NDELAY and O_NONBLOCK are defined to the same thing, we will
 550        print it as O_NONBLOCK, which is good cause that is what POSIX
 551        has, and the flag will already be cleared by the time we get here.  */
 552     if (flags & O_NDELAY)
 553       printf_filtered (" | O_NDELAY");
 554     flags &= ~O_NDELAY;
 555 #endif
 556
 557     if (flags & O_APPEND)
 558       printf_filtered (" | O_APPEND");
 559     flags &= ~O_APPEND;
 560
 561 #if defined (O_BINARY)
 562     if (flags & O_BINARY)
 563       printf_filtered (" | O_BINARY");
 564     flags &= ~O_BINARY;
 565 #endif
 566
 567     if (flags)
 568       printf_filtered (" | 0x%x", flags);
 569     printf_filtered ("\n");
 570   }
 571
 572 #ifdef PROCESS_GROUP_TYPE
 573   printf_filtered ("Process group = %d\n",
 574                    (int) inf->terminal_info->process_group);
 575 #endif
 576
 577   serial_print_tty_state (stdin_serial,
 578                           inf->terminal_info->ttystate,
 579                           gdb_stdout);
 580 }
 581 \f
 582 /* NEW_TTY_PREFORK is called before forking a new child process,
 583    so we can record the state of ttys in the child to be formed.
 584    TTYNAME is null if we are to share the terminal with gdb;
 585    or points to a string containing the name of the desired tty.
 586
 587    NEW_TTY is called in new child processes under Unix, which will
 588    become debugger target processes.  This actually switches to
 589    the terminal specified in the NEW_TTY_PREFORK call.  */
 590
 591 void
 592 new_tty_prefork (const char *ttyname)
 593 {
 594   /* Save the name for later, for determining whether we and the child
 595      are sharing a tty.  */
 596   inferior_thisrun_terminal = ttyname;
 597 }
 598
 599
 600 /* If RESULT, assumed to be the return value from a system call, is
 601    negative, print the error message indicated by errno and exit.
 602    MSG should identify the operation that failed.  */
 603 static void
 604 check_syscall (const char *msg, int result)
 605 {
 606   if (result < 0)
 607     {
 608       print_sys_errmsg (msg, errno);
 609       _exit (1);
 610     }
 611 }
 612
 613 void
 614 new_tty (void)
 615 {
 616   int tty;
 617
 618   if (inferior_thisrun_terminal == 0)
 619     return;
 620 #if !defined(__GO32__) && !defined(_WIN32)
 621 #ifdef TIOCNOTTY
 622   /* Disconnect the child process from our controlling terminal.  On some
 623      systems (SVR4 for example), this may cause a SIGTTOU, so temporarily
 624      ignore SIGTTOU. */
 625   tty = open ("/dev/tty", O_RDWR);
 626   if (tty > 0)
 627     {
 628       void (*osigttou) ();
 629
 630       osigttou = (void (*)()) signal (SIGTTOU, SIG_IGN);
 631       ioctl (tty, TIOCNOTTY, 0);
 632       close (tty);
 633       signal (SIGTTOU, osigttou);
 634     }
 635 #endif
 636
 637   /* Now open the specified new terminal.  */
 638   tty = open (inferior_thisrun_terminal, O_RDWR | O_NOCTTY);
 639   check_syscall (inferior_thisrun_terminal, tty);
 640
 641   /* Avoid use of dup2; doesn't exist on all systems.  */
 642   if (tty != 0)
 643     {
 644       close (0);
 645       check_syscall ("dup'ing tty into fd 0", dup (tty));
 646     }
 647   if (tty != 1)
 648     {
 649       close (1);
 650       check_syscall ("dup'ing tty into fd 1", dup (tty));
 651     }
 652   if (tty != 2)
 653     {
 654       close (2);
 655       check_syscall ("dup'ing tty into fd 2", dup (tty));
 656     }
 657
 658 #ifdef TIOCSCTTY
 659   /* Make tty our new controlling terminal.  */
 660   if (ioctl (tty, TIOCSCTTY, 0) == -1)
 661     /* Mention GDB in warning because it will appear in the inferior's
 662        terminal instead of GDB's.  */
 663     warning ("GDB: Failed to set controlling terminal: %s",
 664              safe_strerror (errno));
 665 #endif
 666
 667   if (tty > 2)
 668     close (tty);
 669 #endif /* !go32 && !win32 */
 670 }
 671 \f
 672 /* Kill the inferior process.  Make us have no inferior.  */
 673
 674 static void
 675 kill_command (char *arg, int from_tty)
 676 {
 677   /* FIXME:  This should not really be inferior_ptid (or target_has_execution).
 678      It should be a distinct flag that indicates that a target is active, cuz
 679      some targets don't have processes! */
 680
 681   if (ptid_equal (inferior_ptid, null_ptid))
 682     error (_("The program is not being run."));
 683   if (!query (_("Kill the program being debugged? ")))
 684     error (_("Not confirmed."));
 685   target_kill ();
 686
 687   /* If the current target interface claims there's still execution,
 688      then don't mess with threads of other processes.  */
 689   if (!target_has_execution)
 690     {
 691       init_thread_list ();              /* Destroy thread info */
 692
 693       /* Killing off the inferior can leave us with a core file.  If
 694          so, print the state we are left in.  */
 695       if (target_has_stack)
 696         {
 697           printf_filtered (_("In %s,\n"), target_longname);
 698           print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
 699         }
 700     }
 701   bfd_cache_close_all ();
 702 }
 703 \f
 704 /* Call set_sigint_trap when you need to pass a signal on to an attached
 705    process when handling SIGINT */
 706
 707 static void
 708 pass_signal (int signo)
 709 {
 710 #ifndef _WIN32
 711   kill (PIDGET (inferior_ptid), SIGINT);
 712 #endif
 713 }
 714
 715 static void (*osig) ();
 716 static int osig_set;
 717
 718 void
 719 set_sigint_trap (void)
 720 {
 721   struct inferior *inf = current_inferior ();
 722   if (inf->attach_flag || inf->terminal_info->run_terminal)
 723     {
 724       osig = (void (*)()) signal (SIGINT, pass_signal);
 725       osig_set = 1;
 726     }
 727   else
 728     osig_set = 0;
 729 }
 730
 731 void
 732 clear_sigint_trap (void)
 733 {
 734   if (osig_set)
 735     {
 736       signal (SIGINT, osig);
 737       osig_set = 0;
 738     }
 739 }
 740 \f
 741
 742 /* Create a new session if the inferior will run in a different tty.
 743    A session is UNIX's way of grouping processes that share a controlling
 744    terminal, so a new one is needed if the inferior terminal will be
 745    different from GDB's.
 746
 747    Returns the session id of the new session, 0 if no session was created
 748    or -1 if an error occurred.  */
 749 pid_t
 750 create_tty_session (void)
 751 {
 752 #ifdef HAVE_SETSID
 753   pid_t ret;
 754
 755   if (!job_control || inferior_thisrun_terminal == 0)
 756     return 0;
 757
 758   ret = setsid ();
 759   if (ret == -1)
 760     warning ("Failed to create new terminal session: setsid: %s",
 761              safe_strerror (errno));
 762
 763   return ret;
 764 #else
 765   return 0;
 766 #endif /* HAVE_SETSID */
 767 }
 768
 769 /* This is here because this is where we figure out whether we (probably)
 770    have job control.  Just using job_control only does part of it because
 771    setpgid or setpgrp might not exist on a system without job control.
 772    It might be considered misplaced (on the other hand, process groups and
 773    job control are closely related to ttys).
 774
 775    For a more clean implementation, in libiberty, put a setpgid which merely
 776    calls setpgrp and a setpgrp which does nothing (any system with job control
 777    will have one or the other).  */
 778 int
 779 gdb_setpgid (void)
 780 {
 781   int retval = 0;
 782
 783   if (job_control)
 784     {
 785 #if defined (HAVE_TERMIOS) || defined (TIOCGPGRP)
 786 #ifdef HAVE_SETPGID
 787       /* The call setpgid (0, 0) is supposed to work and mean the same
 788          thing as this, but on Ultrix 4.2A it fails with EPERM (and
 789          setpgid (getpid (), getpid ()) succeeds).  */
 790       retval = setpgid (getpid (), getpid ());
 791 #else
 792 #ifdef HAVE_SETPGRP
 793 #ifdef SETPGRP_VOID
 794       retval = setpgrp ();
 795 #else
 796       retval = setpgrp (getpid (), getpid ());
 797 #endif
 798 #endif /* HAVE_SETPGRP */
 799 #endif /* HAVE_SETPGID */
 800 #endif /* defined (HAVE_TERMIOS) || defined (TIOCGPGRP) */
 801     }
 802
 803   return retval;
 804 }
 805
 806 /* Get all the current tty settings (including whether we have a
 807    tty at all!).  We can't do this in _initialize_inflow because
 808    serial_fdopen() won't work until the serial_ops_list is
 809    initialized, but we don't want to do it lazily either, so
 810    that we can guarantee stdin_serial is opened if there is
 811    a terminal.  */
 812 void
 813 initialize_stdin_serial (void)
 814 {
 815   stdin_serial = serial_fdopen (0);
 816 }
 817
 818 void
 819 _initialize_inflow (void)
 820 {
 821   add_info ("terminal", term_info,
 822             _("Print inferior's saved terminal status."));
 823
 824   add_com ("kill", class_run, kill_command,
 825            _("Kill execution of program being debugged."));
 826
 827   inferior_ptid = null_ptid;
 828
 829   terminal_is_ours = 1;
 830
 831   /* OK, figure out whether we have job control.  If neither termios nor
 832      sgtty (i.e. termio or go32), leave job_control 0.  */
 833
 834 #if defined (HAVE_TERMIOS)
 835   /* Do all systems with termios have the POSIX way of identifying job
 836      control?  I hope so.  */
 837 #ifdef _POSIX_JOB_CONTROL
 838   job_control = 1;
 839 #else
 840 #ifdef _SC_JOB_CONTROL
 841   job_control = sysconf (_SC_JOB_CONTROL);
 842 #else
 843   job_control = 0;              /* have to assume the worst */
 844 #endif /* _SC_JOB_CONTROL */
 845 #endif /* _POSIX_JOB_CONTROL */
 846 #endif /* HAVE_TERMIOS */
 847
 848 #ifdef HAVE_SGTTY
 849 #ifdef TIOCGPGRP
 850   job_control = 1;
 851 #else
 852   job_control = 0;
 853 #endif /* TIOCGPGRP */
 854 #endif /* sgtty */
 855
 856   observer_attach_new_inferior (inflow_new_inferior);
 857   observer_attach_inferior_exit (inflow_inferior_exit);
 858 }