diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index cc93485..5f489e7 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -1220,6 +1220,7 @@ SFILES = \
 	common/fileio.c \
 	common/filestuff.c \
 	common/format.c \
+	common/job-control.c \
 	common/gdb_vecs.c \
 	common/new-op.c \
 	common/print-utils.c \
@@ -1494,6 +1495,7 @@ HFILES_NO_SRCDIR = \
 	common/common-regcache.h \
 	common/common-types.h \
 	common/common-utils.h \
+	common/job-control.h \
 	common/errors.h \
 	common/environ.h \
 	common/fileio.h \
@@ -1648,6 +1650,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
 	common-agent.o \
 	common-debug.o \
 	common-exceptions.o \
+	job-control.o \
 	common-regcache.o \
 	common-utils.o \
 	complaints.o \
diff --git a/gdb/common/job-control.c b/gdb/common/job-control.c
new file mode 100644
index 0000000..9b993df
--- /dev/null
+++ b/gdb/common/job-control.c
@@ -0,0 +1,93 @@
+/* Job control and terminal related functions, for GDB and gdbserver
+   when running under Unix.
+
+   Copyright (C) 1986-2017 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "common-defs.h"
+#include "job-control.h"
+#include "gdb_termios.h"
+
+/* Nonzero if we have job control.  */
+int job_control;
+
+/* Set the process group ID of the inferior.
+
+   Just using job_control only does part of it because setpgid or
+   setpgrp might not exist on a system without job control.
+
+   For a more clean implementation, in libiberty, put a setpgid which merely
+   calls setpgrp and a setpgrp which does nothing (any system with job control
+   will have one or the other).  */
+
+int
+gdb_setpgid (void)
+{
+  int retval = 0;
+
+  if (job_control)
+    {
+#if defined (HAVE_TERMIOS) || defined (TIOCGPGRP)
+#ifdef HAVE_SETPGID
+      /* The call setpgid (0, 0) is supposed to work and mean the same
+         thing as this, but on Ultrix 4.2A it fails with EPERM (and
+         setpgid (getpid (), getpid ()) succeeds).  */
+      retval = setpgid (getpid (), getpid ());
+#else
+#ifdef HAVE_SETPGRP
+#ifdef SETPGRP_VOID
+      retval = setpgrp ();
+#else
+      retval = setpgrp (getpid (), getpid ());
+#endif
+#endif /* HAVE_SETPGRP */
+#endif /* HAVE_SETPGID */
+#endif /* defined (HAVE_TERMIOS) || defined (TIOCGPGRP) */
+    }
+
+  return retval;
+}
+
+/* See common/common-terminal.h.  */
+
+void
+have_job_control (void)
+{
+  /* OK, figure out whether we have job control.  If neither termios nor
+     sgtty (i.e. termio or go32), leave job_control 0.  */
+#if defined (HAVE_TERMIOS)
+  /* Do all systems with termios have the POSIX way of identifying job
+     control?  I hope so.  */
+#ifdef _POSIX_JOB_CONTROL
+  job_control = 1;
+#else
+#ifdef _SC_JOB_CONTROL
+  job_control = sysconf (_SC_JOB_CONTROL);
+#else
+  job_control = 0;		/* Have to assume the worst.  */
+#endif /* _SC_JOB_CONTROL */
+#endif /* _POSIX_JOB_CONTROL */
+#endif /* HAVE_TERMIOS */
+
+#ifdef HAVE_SGTTY
+#ifdef TIOCGPGRP
+  job_control = 1;
+#else
+  job_control = 0;
+#endif /* TIOCGPGRP */
+#endif /* sgtty */
+}
diff --git a/gdb/common/job-control.h b/gdb/common/job-control.h
new file mode 100644
index 0000000..187cd9f
--- /dev/null
+++ b/gdb/common/job-control.h
@@ -0,0 +1,38 @@
+/* Job control and terminal related functions, for GDB and gdbserver
+   when running under Unix.
+
+   Copyright (C) 1986-2017 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef JOB_CONTROL_H
+#define JOB_CONTROL_H
+
+/* Do we have job control?  Can be assumed to always be the same
+   within a given run of GDB.  Use in gdb/inflow.c and
+   common/common-inflow.c.  */
+extern int job_control;
+
+/* Set the process group of the caller to its own pid, or do nothing
+   if we lack job control.  */
+extern int gdb_setpgid (void);
+
+/* Determine whether we have job control, and set variable JOB_CONTROL
+   accordingly.  This function must be called before any use of
+   JOB_CONTROL.  */
+extern void have_job_control (void);
+
+#endif /* ! JOB_CONTROL_H */
diff --git a/gdb/fork-child.c b/gdb/fork-child.c
index 11ffee9..c1b6f53 100644
--- a/gdb/fork-child.c
+++ b/gdb/fork-child.c
@@ -33,6 +33,7 @@
 #include "filestuff.h"
 #include "top.h"
 #include "signals-state-save-restore.h"
+#include "job-control.h"
 #include <signal.h>
 #include <vector>
 
diff --git a/gdb/gdbserver/Makefile.in b/gdb/gdbserver/Makefile.in
index 01dfdc0..d9f55de 100644
--- a/gdb/gdbserver/Makefile.in
+++ b/gdb/gdbserver/Makefile.in
@@ -204,6 +204,7 @@ SFILES = \
 	$(srcdir)/common/environ.c \
 	$(srcdir)/common/fileio.c \
 	$(srcdir)/common/filestuff.c \
+	$(srcdir)/common/job-control.c \
 	$(srcdir)/common/gdb_vecs.c \
 	$(srcdir)/common/new-op.c \
 	$(srcdir)/common/print-utils.c \
@@ -234,6 +235,7 @@ OBS = \
 	cleanups.o \
 	common-debug.o \
 	common-exceptions.o \
+	job-control.o \
 	common-regcache.o \
 	common-utils.o \
 	debug.o \
diff --git a/gdb/inflow.c b/gdb/inflow.c
index 23dcc4d..01851f4 100644
--- a/gdb/inflow.c
+++ b/gdb/inflow.c
@@ -32,6 +32,7 @@
 #include "inflow.h"
 #include "gdbcmd.h"
 #include "gdb_termios.h"
+#include "job-control.h"
 
 #ifdef HAVE_SYS_IOCTL_H
 #include <sys/ioctl.h>
@@ -804,43 +805,6 @@ create_tty_session (void)
 #endif /* HAVE_SETSID */
 }
 
-/* This is here because this is where we figure out whether we (probably)
-   have job control.  Just using job_control only does part of it because
-   setpgid or setpgrp might not exist on a system without job control.
-   It might be considered misplaced (on the other hand, process groups and
-   job control are closely related to ttys).
-
-   For a more clean implementation, in libiberty, put a setpgid which merely
-   calls setpgrp and a setpgrp which does nothing (any system with job control
-   will have one or the other).  */
-int
-gdb_setpgid (void)
-{
-  int retval = 0;
-
-  if (job_control)
-    {
-#if defined (HAVE_TERMIOS) || defined (TIOCGPGRP)
-#ifdef HAVE_SETPGID
-      /* The call setpgid (0, 0) is supposed to work and mean the same
-         thing as this, but on Ultrix 4.2A it fails with EPERM (and
-         setpgid (getpid (), getpid ()) succeeds).  */
-      retval = setpgid (getpid (), getpid ());
-#else
-#ifdef HAVE_SETPGRP
-#ifdef SETPGRP_VOID 
-      retval = setpgrp ();
-#else
-      retval = setpgrp (getpid (), getpid ());
-#endif
-#endif /* HAVE_SETPGRP */
-#endif /* HAVE_SETPGID */
-#endif /* defined (HAVE_TERMIOS) || defined (TIOCGPGRP) */
-    }
-
-  return retval;
-}
-
 /* Get all the current tty settings (including whether we have a
    tty at all!).  We can't do this in _initialize_inflow because
    serial_fdopen() won't work until the serial_ops_list is
@@ -861,30 +825,8 @@ _initialize_inflow (void)
 
   terminal_is_ours = 1;
 
-  /* OK, figure out whether we have job control.  If neither termios nor
-     sgtty (i.e. termio or go32), leave job_control 0.  */
-
-#if defined (HAVE_TERMIOS)
-  /* Do all systems with termios have the POSIX way of identifying job
-     control?  I hope so.  */
-#ifdef _POSIX_JOB_CONTROL
-  job_control = 1;
-#else
-#ifdef _SC_JOB_CONTROL
-  job_control = sysconf (_SC_JOB_CONTROL);
-#else
-  job_control = 0;		/* Have to assume the worst.  */
-#endif /* _SC_JOB_CONTROL */
-#endif /* _POSIX_JOB_CONTROL */
-#endif /* HAVE_TERMIOS */
-
-#ifdef HAVE_SGTTY
-#ifdef TIOCGPGRP
-  job_control = 1;
-#else
-  job_control = 0;
-#endif /* TIOCGPGRP */
-#endif /* sgtty */
+  /* OK, figure out whether we have job control.  */
+  have_job_control ();
 
   observer_attach_inferior_exit (inflow_inferior_exit);
 
diff --git a/gdb/terminal.h b/gdb/terminal.h
index fb20ae0..0027a3a 100644
--- a/gdb/terminal.h
+++ b/gdb/terminal.h
@@ -29,16 +29,8 @@ extern void new_tty_postfork (void);
 
 extern void copy_terminal_info (struct inferior *to, struct inferior *from);
 
-/* Do we have job control?  Can be assumed to always be the same within
-   a given run of GDB.  In inflow.c.  */
-extern int job_control;
-
 extern pid_t create_tty_session (void);
 
-/* Set the process group of the caller to its own pid, or do nothing if
-   we lack job control.  */
-extern int gdb_setpgid (void);
-
 /* Set up a serial structure describing standard input.  In inflow.c.  */
 extern void initialize_stdin_serial (void);
 
@@ -48,8 +40,4 @@ extern void gdb_save_tty_state (void);
    have had a chance to alter it.  */
 extern void set_initial_gdb_ttystate (void);
 
-/* Set the process group of the caller to its own pid, or do nothing
-   if we lack job control.  */
-extern int gdb_setpgid (void);
-
 #endif /* !defined (TERMINAL_H) */
diff --git a/gdb/top.c b/gdb/top.c
index 3de8a26..17261cc 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -35,6 +35,7 @@
 #include "value.h"
 #include "language.h"
 #include "terminal.h"		/* For job_control.  */
+#include "job-control.h"
 #include "annotate.h"
 #include "completer.h"
 #include "top.h"
diff --git a/gdb/utils.c b/gdb/utils.c
index b4332f8..c61557e 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -65,6 +65,7 @@
 #include "gdb_usleep.h"
 #include "interps.h"
 #include "gdb_regex.h"
+#include "job-control.h"
 
 #if !HAVE_DECL_MALLOC
 extern PTR malloc ();		/* ARI: PTR */
@@ -102,10 +103,6 @@ static std::chrono::steady_clock::duration prompt_for_continue_wait_time;
 
 static int debug_timestamp = 0;
 
-/* Nonzero if we have job control.  */
-
-int job_control;
-
 /* Nonzero means that strings with character values >0x7F should be printed
    as octal escapes.  Zero means just print the value (e.g. it's an
    international character, and the terminal or window can cope.)  */
