builtins/fg_bg.def

   1 This file is fg_bg.def, from which is created fg_bg.c.
   2 It implements the builtins "bg" and "fg" in Bash.
   3
   4 Copyright (C) 1987-2009 Free Software Foundation, Inc.
   5
   6 This file is part of GNU Bash, the Bourne Again SHell.
   7
   8 Bash 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 Bash 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 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]
  27 Move job to the foreground.
  28
  29 Place the job identified by JOB_SPEC in the foreground, making it the
  30 current job.  If JOB_SPEC is not present, the shell's notion of the
  31 current job is used.
  32
  33 Exit Status:
  34 Status 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)
  54 extern char *this_command_name;
  55
  56 static int fg_bg __P((WORD_LIST *, int));
  57
  58 /* How to bring a job into the foreground. */
  59 int
  60 fg_builtin (list)
  61      WORD_LIST *list;
  62 {
  63   int fg_bit;
  64   register WORD_LIST *t;
  65
  66   CHECK_HELPOPT (list);
  67
  68   if (job_control == 0)
  69     {
  70       sh_nojobs ((char *)NULL);
  71       return (EXECUTION_FAILURE);
  72     }
  73
  74   if (no_options (list))
  75     return (EX_USAGE);
  76   list = loptend;
  77
  78   /* If the last arg on the line is '&', then start this job in the
  79      background.  Else, fg the job. */
  80   for (t = list; t && t->next; t = t->next)
  81     ;
  82   fg_bit = (t && t->word->word[0] == '&' && t->word->word[1] == '\0') == 0;
  83
  84   return (fg_bg (list, fg_bit));
  85 }
  86 #endif /* JOB_CONTROL */
  87
  88 $BUILTIN bg
  89 $FUNCTION bg_builtin
  90 $DEPENDS_ON JOB_CONTROL
  91 $SHORT_DOC bg [job_spec ...]
  92 Move jobs to the background.
  93
  94 Place the jobs identified by each JOB_SPEC in the background, as if they
  95 had been started with `&'.  If JOB_SPEC is not present, the shell's notion
  96 of the current job is used.
  97
  98 Exit Status:
  99 Returns success unless job control is not enabled or an error occurs.
 100 $END
 101
 102 #if defined (JOB_CONTROL)
 103 /* How to put a job into the background. */
 104 int
 105 bg_builtin (list)
 106      WORD_LIST *list;
 107 {
 108   int r;
 109
 110   CHECK_HELPOPT (list);
 111
 112   if (job_control == 0)
 113     {
 114       sh_nojobs ((char *)NULL);
 115       return (EXECUTION_FAILURE);
 116     }
 117
 118   if (no_options (list))
 119     return (EX_USAGE);
 120   list = loptend;
 121
 122   /* This relies on the fact that fg_bg() takes a WORD_LIST *, but only acts
 123      on the first member (if any) of that list. */
 124   r = EXECUTION_SUCCESS;
 125   do
 126     {
 127       if (fg_bg (list, 0) == EXECUTION_FAILURE)
 128         r = EXECUTION_FAILURE;
 129       if (list)
 130         list = list->next;
 131     }
 132   while (list);
 133
 134   return r;
 135 }
 136
 137 /* How to put a job into the foreground/background. */
 138 static int
 139 fg_bg (list, foreground)
 140      WORD_LIST *list;
 141      int foreground;
 142 {
 143   sigset_t set, oset;
 144   int job, status, old_async_pid;
 145   JOB *j;
 146
 147   BLOCK_CHILD (set, oset);
 148   job = get_job_spec (list);
 149
 150   if (INVALID_JOB (job))
 151     {
 152       if (job != DUP_JOB)
 153         sh_badjob (list ? list->word->word : _("current"));
 154
 155       goto failure;
 156     }
 157
 158   j = get_job_by_jid (job);
 159   /* Or if j->pgrp == shell_pgrp. */
 160   if (IS_JOBCONTROL (job) == 0)
 161     {
 162       builtin_error (_("job %d started without job control"), job + 1);
 163       goto failure;
 164     }
 165
 166   if (foreground == 0)
 167     {
 168       old_async_pid = last_asynchronous_pid;
 169       last_asynchronous_pid = j->pgrp;  /* As per Posix.2 5.4.2 */
 170     }
 171
 172   status = start_job (job, foreground);
 173
 174   if (status >= 0)
 175     {
 176     /* win: */
 177       UNBLOCK_CHILD (oset);
 178       return (foreground ? status : EXECUTION_SUCCESS);
 179     }
 180   else
 181     {
 182       if (foreground == 0)
 183         last_asynchronous_pid = old_async_pid;
 184
 185     failure:
 186       UNBLOCK_CHILD (oset);
 187       return (EXECUTION_FAILURE);
 188     }
 189 }
 190 #endif /* JOB_CONTROL */