1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25 
  26 #pragma ident   "%Z%%M% %I%     %E% SMI"
  27 
  28 #include <sys/types.h>
  29 #include <sys/systm.h>
  30 #include <sys/errno.h>
  31 
  32 /*
  33  * The brk() system call needs to be in-kernel because Linux expects a call to
  34  * brk(0) to return the current breakpoint.  In Solaris, the process breakpoint
  35  * is setup and managed by libc.  Due to the way we link our libraries and the
  36  * need for Linux to manage its own breakpoint, this has to remain in the
  37  * kernel.
  38  */
  39 extern int brk(caddr_t);
  40 
  41 long
  42 lx_brk(caddr_t nva)
  43 {
  44         proc_t *p = curproc;
  45         klwp_t *lwp = ttolwp(curthread);
  46 
  47         if (nva != 0) {
  48                 (void) brk(nva);
  49 
  50                 /*
  51                  * Despite claims to the contrary in the manpage, when Linux
  52                  * brk() fails, errno is left unchanged.
  53                  */
  54                 lwp->lwp_errno = 0;
  55         }
  56         return ((long)(p->p_brkbase + p->p_brksize));
  57 }