gdbsupport/job-control.cc

   1 /* Job control and terminal related functions, for GDB and gdbserver
   2    when running under Unix.
   3
   4    Copyright (C) 1986-2024 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 "job-control.h"
  22 #ifdef HAVE_TERMIOS_H
  23 #include <termios.h>
  24 #endif
  25 #include <unistd.h>
  26
  27 /* Nonzero if we have job control.  */
  28 int job_control;
  29
  30 /* Set the process group ID of the inferior.
  31
  32    Just using job_control only does part of it because setpgid or
  33    setpgrp might not exist on a system without job control.
  34
  35    For a more clean implementation, in libiberty, put a setpgid which merely
  36    calls setpgrp and a setpgrp which does nothing (any system with job control
  37    will have one or the other).  */
  38
  39 int
  40 gdb_setpgid ()
  41 {
  42   int retval = 0;
  43
  44   if (job_control)
  45     {
  46 #ifdef HAVE_SETPGID
  47       /* The call setpgid (0, 0) is supposed to work and mean the same
  48          thing as this, but on Ultrix 4.2A it fails with EPERM (and
  49          setpgid (getpid (), getpid ()) succeeds).  */
  50       retval = setpgid (getpid (), getpid ());
  51 #else
  52 #ifdef HAVE_SETPGRP
  53 #ifdef SETPGRP_VOID
  54       retval = setpgrp ();
  55 #else
  56       retval = setpgrp (getpid (), getpid ());
  57 #endif
  58 #endif /* HAVE_SETPGRP */
  59 #endif /* HAVE_SETPGID */
  60     }
  61
  62   return retval;
  63 }
  64
  65 /* See gdbsupport/common-terminal.h.  */
  66
  67 void
  68 have_job_control ()
  69 {
  70   /* OK, figure out whether we have job control.  If termios is not
  71      available, leave job_control 0.  */
  72 #if defined (HAVE_TERMIOS_H)
  73   /* Do all systems with termios have the POSIX way of identifying job
  74      control?  I hope so.  */
  75 #ifdef _POSIX_JOB_CONTROL
  76   job_control = 1;
  77 #else
  78 #ifdef _SC_JOB_CONTROL
  79   job_control = sysconf (_SC_JOB_CONTROL);
  80 #else
  81   job_control = 0;              /* Have to assume the worst.  */
  82 #endif /* _SC_JOB_CONTROL */
  83 #endif /* _POSIX_JOB_CONTROL */
  84 #endif /* HAVE_TERMIOS_H */
  85 }