1This file is fg_bg.def, from which is created fg_bg.c.
2It implements the builtins "bg" and "fg" in Bash.
3
4Copyright (C) 1987-2009 Free Software Foundation, Inc.
5
6This file is part of GNU Bash, the Bourne Again SHell.
7
8Bash is free software: you can redistribute it and/or modify
9it under the terms of the GNU General Public License as published by
10the Free Software Foundation, either version 3 of the License, or
11(at your option) any later version.
12
13Bash is distributed in the hope that it will be useful,
14but WITHOUT ANY WARRANTY; without even the implied warranty of
15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16GNU General Public License for more details.
17
18You should have received a copy of the GNU General Public License
19along with Bash.  If not, see <http://www.gnu.org/licenses/>.
20
21$PRODUCES fg_bg.c
22
23$BUILTIN fg
24$FUNCTION fg_builtin
25$DEPENDS_ON JOB_CONTROL
26$SHORT_DOC fg [job_spec]
27Move job to the foreground.
28
29Place the job identified by JOB_SPEC in the foreground, making it the
30current job.  If JOB_SPEC is not present, the shell's notion of the
31current job is used.
32
33Exit Status:
34Status of command placed in foreground, or failure if an error occurs.
35$END
36
37#include <config.h>
38
39#include "../bashtypes.h"
40#include <signal.h>
41
42#if defined (HAVE_UNISTD_H)
43#  include <unistd.h>
44#endif
45
46#include "../bashintl.h"
47
48#include "../shell.h"
49#include "../jobs.h"
50#include "common.h"
51#include "bashgetopt.h"
52
53#if defined (JOB_CONTROL)
54extern char *this_command_name;
55
56static int fg_bg __P((WORD_LIST *, int));
57
58/* How to bring a job into the foreground. */
59int
60fg_builtin (list)
61     WORD_LIST *list;
62{
63  int fg_bit;
64  register WORD_LIST *t;
65
66  if (job_control == 0)
67    {
68      sh_nojobs ((char *)NULL);
69      return (EXECUTION_FAILURE);
70    }
71
72  if (no_options (list))
73    return (EX_USAGE);
74  list = loptend;
75
76  /* If the last arg on the line is '&', then start this job in the
77     background.  Else, fg the job. */
78  for (t = list; t && t->next; t = t->next)
79    ;
80  fg_bit = (t && t->word->word[0] == '&' && t->word->word[1] == '\0') == 0;
81
82  return (fg_bg (list, fg_bit));
83}
84#endif /* JOB_CONTROL */
85
86$BUILTIN bg
87$FUNCTION bg_builtin
88$DEPENDS_ON JOB_CONTROL
89$SHORT_DOC bg [job_spec ...]
90Move jobs to the background.
91
92Place the jobs identified by each JOB_SPEC in the background, as if they
93had been started with `&'.  If JOB_SPEC is not present, the shell's notion
94of the current job is used.
95
96Exit Status:
97Returns success unless job control is not enabled or an error occurs.
98$END
99
100#if defined (JOB_CONTROL)
101/* How to put a job into the background. */
102int
103bg_builtin (list)
104     WORD_LIST *list;
105{
106  int r;
107
108  if (job_control == 0)
109    {
110      sh_nojobs ((char *)NULL);
111      return (EXECUTION_FAILURE);
112    }
113
114  if (no_options (list))
115    return (EX_USAGE);
116  list = loptend;
117
118  /* This relies on the fact that fg_bg() takes a WORD_LIST *, but only acts
119     on the first member (if any) of that list. */
120  r = EXECUTION_SUCCESS;
121  do
122    {
123      if (fg_bg (list, 0) == EXECUTION_FAILURE)
124	r = EXECUTION_FAILURE;
125      if (list)
126	list = list->next;
127    }
128  while (list);
129
130  return r;
131}
132
133/* How to put a job into the foreground/background. */
134static int
135fg_bg (list, foreground)
136     WORD_LIST *list;
137     int foreground;
138{
139  sigset_t set, oset;
140  int job, status, old_async_pid;
141  JOB *j;
142
143  BLOCK_CHILD (set, oset);
144  job = get_job_spec (list);
145
146  if (INVALID_JOB (job))
147    {
148      if (job != DUP_JOB)
149	sh_badjob (list ? list->word->word : _("current"));
150
151      goto failure;
152    }
153
154  j = get_job_by_jid (job);
155  /* Or if j->pgrp == shell_pgrp. */
156  if (IS_JOBCONTROL (job) == 0)
157    {
158      builtin_error (_("job %d started without job control"), job + 1);
159      goto failure;
160    }
161
162  if (foreground == 0)
163    {
164      old_async_pid = last_asynchronous_pid;
165      last_asynchronous_pid = j->pgrp;	/* As per Posix.2 5.4.2 */
166    }
167
168  status = start_job (job, foreground);
169
170  if (status >= 0)
171    {
172    /* win: */
173      UNBLOCK_CHILD (oset);
174      return (foreground ? status : EXECUTION_SUCCESS);
175    }
176  else
177    {
178      if (foreground == 0)
179	last_asynchronous_pid = old_async_pid;
180
181    failure:
182      UNBLOCK_CHILD (oset);
183      return (EXECUTION_FAILURE);
184    }
185}
186#endif /* JOB_CONTROL */
187