bash-5.1-alpha release

[thirdparty/bash.git] / examples / loadables / setpgid.c

/* setpgid.c: bash loadable wrapper for setpgid system call

   An example of how to wrap a system call with a loadable builtin.

   Originally contributed by Jason Vas Dias <jason.vas.dias@gmail.com>
   
   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/>.
*/

#include <config.h>

#if defined (HAVE_UNISTD_H)
#  include <unistd.h>
#endif
#include <errno.h>
#include <string.h>

#include "bashtypes.h"
#include "posixtime.h"

#include <stdio.h>

#include "builtins.h"
#include "shell.h"
#include "common.h"

#include "bashgetopt.h"

#if !defined (_POSIX_VERSION)
#  define setpgid(pid, pgrp)      setpgrp (pid, pgrp)
#endif

int
setpgid_builtin (list)
      WORD_LIST *list;
{
  register WORD_LIST *wl;
  intmax_t pid_arg, pgid_arg;
  pid_t pid, pgid;
  char *pidstr, *pgidstr;

  wl = list;
  pid = pgid = 0;

  if (wl == 0 || wl->next == 0)
    {
      builtin_usage ();
      return (EX_USAGE);
    }

  pidstr = wl->word ? wl->word->word : 0;
  pgidstr = wl->next->word ? wl->next->word->word : 0;

  if (pidstr == 0 || pgidstr == 0)
    {
      builtin_usage ();
      return (EX_USAGE);
    }
      
  if (legal_number (pidstr, &pid_arg) == 0)
    {
      builtin_error ("%s: pid argument must be numeric", pidstr);
      return (EXECUTION_FAILURE);
    }
  if (pid_arg < 0)
    {
      builtin_error("%s: negative pid  values not allowed", pidstr);
      return (EXECUTION_FAILURE);
    }
  pid = pid_arg;

  if (legal_number (pgidstr, &pgid_arg) == 0)
    {
      builtin_error ("%s: pgrp argument must be numeric", pgidstr);
      return (EXECUTION_FAILURE);
    }
  if (pgid_arg < 0)
    {
      builtin_error ("%s: negative pgrp values not allowed", pgidstr);
      return (EXECUTION_FAILURE);
    }
  pgid = pgid_arg;

  errno = 0;
  if (setpgid(pid, pgid) < 0)
    {
      builtin_error("setpgid failed: %s", strerror (errno));
      return (EXECUTION_FAILURE);     
    }
  return (EXECUTION_SUCCESS);     
}

const char *setpgid_doc[] = {
	"invoke the setpgid(2) system call",
	"",
	"Arguments:",
	"   pid : numeric process identifier, >= 0",
	"   pgrpid: numeric process group identifier, >=0",
	"See the setpgid(2) manual page.",
	(const char *)NULL
};

struct builtin setpgid_struct = {
	"setpgid",
	setpgid_builtin,
	BUILTIN_ENABLED,
	(char **)setpgid_doc,
	"setpgid pid pgrpid",
	0
};