glibc/sysdeps/unix/bsd/ulimit.c

/* Copyright (C) 1991,1992,1994-1998,2001,2005 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <stdarg.h>
#include <sysdep.h>
#include <ulimit.h>
#include <unistd.h>
#include <sys/resource.h>


extern int _etext;

/* Function depends on CMD:
   1 = Return the limit on the size of a file, in units of 512 bytes.
   2 = Set the limit on the size of a file to NEWLIMIT.  Only the
       super-user can increase the limit.
   3 = Return the maximum possible address of the data segment.
   4 = Return the maximum number of files that the calling process
       can open.
   Returns -1 on errors.  */
long int
ulimit (int cmd, ...)
{
  struct rlimit limit;
  va_list va;
  long int result = -1;

  va_start (va, cmd);

  switch (cmd)
    {
    case UL_GETFSIZE:
      /* Get limit on file size.  */
      if (getrlimit (RLIMIT_FSIZE, &limit) == 0)
	/* Convert from bytes to 512 byte units.  */
	result = limit.rlim_cur / 512;
      break;

    case UL_SETFSIZE:
      /* Set limit on file size.  */
      {
	long int newlimit = va_arg (va, long int);

	if ((rlim_t) newlimit > RLIM_INFINITY / 512)
	  {
	    limit.rlim_cur = RLIM_INFINITY;
	    limit.rlim_max = RLIM_INFINITY;
	  }
	else
	  {
	    limit.rlim_cur = newlimit * 512;
	    limit.rlim_max = newlimit * 512;
	  }

	result = setrlimit (RLIMIT_FSIZE, &limit);
      }
      break;

    case __UL_GETMAXBRK:
      /* Get maximum address for `brk'.  */
      if (getrlimit (RLIMIT_DATA, &limit) == 0)
	result = ((long int) &_etext) + limit.rlim_cur;
      break;

    case __UL_GETOPENMAX:
      result = sysconf (_SC_OPEN_MAX);
      break;

    default:
      __set_errno (EINVAL);
    }

  va_end (va);

  return result;
}