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This file is fg_bg.def, from which is created fg_bg.c.
It implements the builtins "bg" and "fg" in Bash.
Copyright (C) 1987-2009 Free Software Foundation, Inc.
This file is part of GNU Bash, the Bourne Again SHell.
Bash 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.
Bash 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 Bash. If not, see <http://www.gnu.org/licenses/>.
$PRODUCES fg_bg.c
$BUILTIN fg
$FUNCTION fg_builtin
$DEPENDS_ON JOB_CONTROL
$SHORT_DOC fg [job_spec]
Move job to the foreground.
Place the job identified by JOB_SPEC in the foreground, making it the
current job. If JOB_SPEC is not present, the shell's notion of the
current job is used.
Exit Status:
Status of command placed in foreground, or failure if an error occurs.
$END
#include <config.h>
#include "../bashtypes.h"
#include <signal.h>
#if defined (HAVE_UNISTD_H)
# include <unistd.h>
#endif
#include "../bashintl.h"
#include "../shell.h"
#include "../jobs.h"
#include "common.h"
#include "bashgetopt.h"
#if defined (JOB_CONTROL)
extern char *this_command_name;
static int fg_bg __P((WORD_LIST *, int));
/* How to bring a job into the foreground. */
int
fg_builtin (list)
WORD_LIST *list;
{
int fg_bit;
register WORD_LIST *t;
if (job_control == 0)
{
sh_nojobs ((char *)NULL);
return (EXECUTION_FAILURE);
}
if (no_options (list))
return (EX_USAGE);
list = loptend;
/* If the last arg on the line is '&', then start this job in the
background. Else, fg the job. */
for (t = list; t && t->next; t = t->next)
;
fg_bit = (t && t->word->word[0] == '&' && t->word->word[1] == '\0') == 0;
return (fg_bg (list, fg_bit));
}
#endif /* JOB_CONTROL */
$BUILTIN bg
$FUNCTION bg_builtin
$DEPENDS_ON JOB_CONTROL
$SHORT_DOC bg [job_spec ...]
Move jobs to the background.
Place the jobs identified by each JOB_SPEC in the background, as if they
had been started with `&'. If JOB_SPEC is not present, the shell's notion
of the current job is used.
Exit Status:
Returns success unless job control is not enabled or an error occurs.
$END
#if defined (JOB_CONTROL)
/* How to put a job into the background. */
int
bg_builtin (list)
WORD_LIST *list;
{
int r;
if (job_control == 0)
{
sh_nojobs ((char *)NULL);
return (EXECUTION_FAILURE);
}
if (no_options (list))
return (EX_USAGE);
list = loptend;
/* This relies on the fact that fg_bg() takes a WORD_LIST *, but only acts
on the first member (if any) of that list. */
r = EXECUTION_SUCCESS;
do
{
if (fg_bg (list, 0) == EXECUTION_FAILURE)
r = EXECUTION_FAILURE;
if (list)
list = list->next;
}
while (list);
return r;
}
/* How to put a job into the foreground/background. */
static int
fg_bg (list, foreground)
WORD_LIST *list;
int foreground;
{
sigset_t set, oset;
int job, status, old_async_pid;
JOB *j;
BLOCK_CHILD (set, oset);
job = get_job_spec (list);
if (INVALID_JOB (job))
{
if (job != DUP_JOB)
sh_badjob (list ? list->word->word : _("current"));
goto failure;
}
j = get_job_by_jid (job);
/* Or if j->pgrp == shell_pgrp. */
if (IS_JOBCONTROL (job) == 0)
{
builtin_error (_("job %d started without job control"), job + 1);
goto failure;
}
if (foreground == 0)
{
old_async_pid = last_asynchronous_pid;
last_asynchronous_pid = j->pgrp; /* As per Posix.2 5.4.2 */
}
status = start_job (job, foreground);
if (status >= 0)
{
/* win: */
UNBLOCK_CHILD (oset);
return (foreground ? status : EXECUTION_SUCCESS);
}
else
{
if (foreground == 0)
last_asynchronous_pid = old_async_pid;
failure:
UNBLOCK_CHILD (oset);
return (EXECUTION_FAILURE);
}
}
#endif /* JOB_CONTROL */
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