examples/loadables/push.c

   1 /*
   2  * push - anyone remember TOPS-20?
   3  *
   4  */
   5
   6 #include <config.h>
   7 #include <stdio.h>
   8 #include <errno.h>
   9
  10 #include "builtins.h"
  11 #include "shell.h"
  12 #include "jobs.h"
  13 #include "bashgetopt.h"
  14
  15 #ifndef errno
  16 extern int errno;
  17 #endif
  18
  19 extern int dollar_dollar_pid;
  20 extern int last_command_exit_value;
  21
  22 int
  23 push_builtin (list)
  24      WORD_LIST *list;
  25 {
  26   pid_t pid;
  27   int xstatus, opt;
  28
  29   xstatus = EXECUTION_SUCCESS;
  30   reset_internal_getopt ();
  31   while ((opt = internal_getopt (list, "")) != -1)
  32     {
  33       switch (opt)
  34         {
  35         default:
  36           builtin_usage ();
  37           return (EX_USAGE);
  38         }
  39     }
  40   list = loptend;
  41
  42   pid = make_child (savestring ("push"), 0);
  43   if (pid == -1)
  44     {
  45       builtin_error ("cannot fork: %s", strerror (errno));
  46       return (EXECUTION_FAILURE);
  47     }
  48   else if (pid == 0)
  49     {
  50       /* Shell variable adjustments: $SHLVL, $$, $PPID, $! */
  51       adjust_shell_level (1);
  52       dollar_dollar_pid = getpid ();
  53       set_ppid ();
  54
  55       /* Clean up job control stuff. */
  56       stop_making_children ();
  57       cleanup_the_pipeline ();
  58       delete_all_jobs (0);
  59
  60       last_asynchronous_pid = NO_PID;
  61
  62       /* Make sure the job control code has the right values for
  63          the shell's process group and tty process group, and that
  64          the signals are set correctly for job control. */
  65       initialize_job_control (0);
  66       initialize_job_signals ();
  67
  68       /* And read commands until exit. */
  69       reader_loop ();
  70       exit_shell (last_command_exit_value);
  71     }
  72   else
  73     {
  74       stop_pipeline (0, (COMMAND *)NULL);
  75       xstatus = wait_for (pid);
  76       return (xstatus);
  77     }
  78 }
  79
  80 char *push_doc[] = {
  81         "Create a child that is an exact duplicate of the running shell",
  82         "and wait for it to exit.  The $SHLVL, $!, $$, and $PPID variables",
  83         "are adjusted in the child.  The return value is the exit status",
  84         "of the child.",
  85         (char *)NULL
  86 };
  87
  88 struct builtin push_struct = {
  89         "push",
  90         push_builtin,
  91         BUILTIN_ENABLED,
  92         push_doc,
  93         "push",
  94         0
  95 };