1/* Common definitions for handling files in memory or only on disk.
2   Copyright (C) 1998, 1999, 2000, 2002, 2005, 2008 Red Hat, Inc.
3   This file is part of Red Hat elfutils.
4   Written by Ulrich Drepper <drepper@redhat.com>, 1998.
5
6   Red Hat elfutils is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by the
8   Free Software Foundation; version 2 of the License.
9
10   Red Hat elfutils is distributed in the hope that it will be useful, but
11   WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   General Public License for more details.
14
15   You should have received a copy of the GNU General Public License along
16   with Red Hat elfutils; if not, write to the Free Software Foundation,
17   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
18
19   In addition, as a special exception, Red Hat, Inc. gives You the
20   additional right to link the code of Red Hat elfutils with code licensed
21   under any Open Source Initiative certified open source license
22   (http://www.opensource.org/licenses/index.php) which requires the
23   distribution of source code with any binary distribution and to
24   distribute linked combinations of the two.  Non-GPL Code permitted under
25   this exception must only link to the code of Red Hat elfutils through
26   those well defined interfaces identified in the file named EXCEPTION
27   found in the source code files (the "Approved Interfaces").  The files
28   of Non-GPL Code may instantiate templates or use macros or inline
29   functions from the Approved Interfaces without causing the resulting
30   work to be covered by the GNU General Public License.  Only Red Hat,
31   Inc. may make changes or additions to the list of Approved Interfaces.
32   Red Hat's grant of this exception is conditioned upon your not adding
33   any new exceptions.  If you wish to add a new Approved Interface or
34   exception, please contact Red Hat.  You must obey the GNU General Public
35   License in all respects for all of the Red Hat elfutils code and other
36   code used in conjunction with Red Hat elfutils except the Non-GPL Code
37   covered by this exception.  If you modify this file, you may extend this
38   exception to your version of the file, but you are not obligated to do
39   so.  If you do not wish to provide this exception without modification,
40   you must delete this exception statement from your version and license
41   this file solely under the GPL without exception.
42
43   Red Hat elfutils is an included package of the Open Invention Network.
44   An included package of the Open Invention Network is a package for which
45   Open Invention Network licensees cross-license their patents.  No patent
46   license is granted, either expressly or impliedly, by designation as an
47   included package.  Should you wish to participate in the Open Invention
48   Network licensing program, please visit www.openinventionnetwork.com
49   <http://www.openinventionnetwork.com>.  */
50
51#ifndef _COMMON_H
52#define _COMMON_H       1
53
54#include <ar.h>
55#include <byteswap.h>
56#include <endian.h>
57#include <stdlib.h>
58#include <string.h>
59
60#include "libelfP.h"
61
62static inline Elf_Kind
63__attribute__ ((unused))
64determine_kind (void *buf, size_t len)
65{
66  /* First test for an archive.  */
67  if (len >= SARMAG && memcmp (buf, ARMAG, SARMAG) == 0)
68    return ELF_K_AR;
69
70  /* Next try ELF files.  */
71  if (len >= EI_NIDENT && memcmp (buf, ELFMAG, SELFMAG) == 0)
72    {
73      /* Could be an ELF file.  */
74      int eclass = (int) ((unsigned char *) buf)[EI_CLASS];
75      int data = (int) ((unsigned char *) buf)[EI_DATA];
76      int version = (int) ((unsigned char *) buf)[EI_VERSION];
77
78      if (eclass > ELFCLASSNONE && eclass < ELFCLASSNUM
79	  && data > ELFDATANONE && data < ELFDATANUM
80	  && version > EV_NONE && version < EV_NUM)
81	return ELF_K_ELF;
82    }
83
84  /* We do not know this file type.  */
85  return ELF_K_NONE;
86}
87
88
89/* Allocate an Elf descriptor and fill in the generic information.  */
90static inline Elf *
91__attribute__ ((unused))
92allocate_elf (int fildes, void *map_address, off_t offset, size_t maxsize,
93              Elf_Cmd cmd, Elf *parent, Elf_Kind kind, size_t extra)
94{
95  Elf *result = (Elf *) calloc (1, sizeof (Elf) + extra);
96  if (result == NULL)
97    __libelf_seterrno (ELF_E_NOMEM);
98  else
99    {
100      result->kind = kind;
101      result->ref_count = 1;
102      result->cmd = cmd;
103      result->fildes = fildes;
104      result->start_offset = offset;
105      result->maximum_size = maxsize;
106      result->map_address = map_address;
107      result->parent = parent;
108
109      rwlock_init (result->lock);
110    }
111
112  return result;
113}
114
115
116/* Acquire lock for the descriptor and all children.  */
117static void
118__attribute__ ((unused))
119libelf_acquire_all (Elf *elf)
120{
121  rwlock_wrlock (elf->lock);
122
123  if (elf->kind == ELF_K_AR)
124    {
125      Elf *child = elf->state.ar.children;
126
127      while (child != NULL)
128	{
129	  if (child->ref_count != 0)
130	    libelf_acquire_all (child);
131	  child = child->next;
132	}
133    }
134}
135
136/* Release own lock and those of the children.  */
137static void
138__attribute__ ((unused))
139libelf_release_all (Elf *elf)
140{
141  if (elf->kind == ELF_K_AR)
142    {
143      Elf *child = elf->state.ar.children;
144
145      while (child != NULL)
146	{
147	  if (child->ref_count != 0)
148	    libelf_release_all (child);
149	  child = child->next;
150	}
151    }
152
153  rwlock_unlock (elf->lock);
154}
155
156
157/* Macro to convert endianess in place.  It determines the function it
158   has to use itself.  */
159#define CONVERT(Var) \
160  (Var) = (sizeof (Var) == 1						      \
161	   ? (unsigned char) (Var)					      \
162	   : (sizeof (Var) == 2						      \
163	      ? bswap_16 (Var)						      \
164	      : (sizeof (Var) == 4					      \
165		 ? bswap_32 (Var)					      \
166		 : bswap_64 (Var))))
167
168#define CONVERT_TO(Dst, Var) \
169  (Dst) = (sizeof (Var) == 1						      \
170	   ? (unsigned char) (Var)					      \
171	   : (sizeof (Var) == 2						      \
172	      ? bswap_16 (Var)						      \
173	      : (sizeof (Var) == 4					      \
174		 ? bswap_32 (Var)					      \
175		 : bswap_64 (Var))))
176
177
178#if __BYTE_ORDER == __LITTLE_ENDIAN
179# define MY_ELFDATA	ELFDATA2LSB
180#else
181# define MY_ELFDATA	ELFDATA2MSB
182#endif
183
184#endif	/* common.h */
185