usr/src/cmd/sgs/libelf/common/newdata.c

   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 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #include "libelf.h"
  31 #include "decl.h"
  32 #include "msg.h"
  33
  34
  35 Elf_Data *
  36 elf_newdata(Elf_Scn * s)
  37 {
  38         Dnode *         d;
  39         Elf_Data *      rc;
  40         Elf *           elf;
  41         unsigned        work;
  42
  43         if (s == 0)
  44                 return (0);
  45         elf = s->s_elf;
  46         READLOCKS(elf, s)
  47         if (s->s_index == SHN_UNDEF) {
  48                 _elf_seterr(EREQ_SCNNULL, 0);
  49                 READUNLOCKS(elf, s)
  50                 return (0);
  51         }
  52
  53         if ((s->s_myflags & SF_READY) == 0) {
  54                 UPGRADELOCKS(elf, s)
  55                 /*
  56                  * re-confirm that another 'thread' hasn't come along
  57                  * and cooked this section while the locks were
  58                  * obtained.
  59                  */
  60                 if ((s->s_myflags & SF_READY) == 0)
  61                         (void) _elf_cookscn(s);
  62                 DOWNGRADELOCKS(elf, s)
  63         }
  64
  65         /*
  66          * If this is the first new node, use the one allocated
  67          * in the scn itself.  Update data buffer in both cases.
  68          */
  69         ELFACCESSDATA(work, _elf_work)
  70         if (s->s_hdnode == 0) {
  71                 s->s_dnode.db_uflags |= ELF_F_DIRTY;
  72                 s->s_dnode.db_myflags |= DBF_READY;
  73                 s->s_hdnode = &s->s_dnode;
  74                 s->s_tlnode = &s->s_dnode;
  75                 s->s_dnode.db_scn = s;
  76                 s->s_dnode.db_data.d_version = work;
  77                 rc = &s->s_dnode.db_data;
  78                 READUNLOCKS(elf, s)
  79                 return (rc);
  80         }
  81         if ((d = _elf_dnode()) == 0) {
  82                 READUNLOCKS(elf, s)
  83                 return (0);
  84         }
  85         d->db_data.d_version = work;
  86         d->db_scn = s;
  87         d->db_uflags |= ELF_F_DIRTY;
  88         d->db_myflags |= DBF_READY;
  89         s->s_tlnode->db_next = d;
  90         s->s_tlnode = d;
  91         rc = &d->db_data;
  92         READUNLOCKS(elf, s)
  93         return (rc);
  94 }