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 elfutils.
4   Written by Ulrich Drepper <drepper@redhat.com>, 1998.
5
6   This file is free software; you can redistribute it and/or modify
7   it under the terms of either
8
9     * the GNU Lesser General Public License as published by the Free
10       Software Foundation; either version 3 of the License, or (at
11       your option) any later version
12
13   or
14
15     * the GNU General Public License as published by the Free
16       Software Foundation; either version 2 of the License, or (at
17       your option) any later version
18
19   or both in parallel, as here.
20
21   elfutils is distributed in the hope that it will be useful, but
22   WITHOUT ANY WARRANTY; without even the implied warranty of
23   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
24   General Public License for more details.
25
26   You should have received copies of the GNU General Public License and
27   the GNU Lesser General Public License along with this program.  If
28   not, see <http://www.gnu.org/licenses/>.  */
29
30#ifndef _COMMON_H
31#define _COMMON_H       1
32
33#include <ar.h>
34#include <byteswap.h>
35#include <endian.h>
36#include <stdlib.h>
37#include <string.h>
38
39#include "libelfP.h"
40
41static inline Elf_Kind
42__attribute__ ((unused))
43determine_kind (void *buf, size_t len)
44{
45  /* First test for an archive.  */
46  if (len >= SARMAG && memcmp (buf, ARMAG, SARMAG) == 0)
47    return ELF_K_AR;
48
49  /* Next try ELF files.  */
50  if (len >= EI_NIDENT && memcmp (buf, ELFMAG, SELFMAG) == 0)
51    {
52      /* Could be an ELF file.  */
53      int eclass = (int) ((unsigned char *) buf)[EI_CLASS];
54      int data = (int) ((unsigned char *) buf)[EI_DATA];
55      int version = (int) ((unsigned char *) buf)[EI_VERSION];
56
57      if (eclass > ELFCLASSNONE && eclass < ELFCLASSNUM
58	  && data > ELFDATANONE && data < ELFDATANUM
59	  && version > EV_NONE && version < EV_NUM)
60	return ELF_K_ELF;
61    }
62
63  /* We do not know this file type.  */
64  return ELF_K_NONE;
65}
66
67
68/* Allocate an Elf descriptor and fill in the generic information.  */
69static inline Elf *
70__attribute__ ((unused))
71allocate_elf (int fildes, void *map_address, off_t offset, size_t maxsize,
72              Elf_Cmd cmd, Elf *parent, Elf_Kind kind, size_t extra)
73{
74  Elf *result = (Elf *) calloc (1, sizeof (Elf) + extra);
75  if (result == NULL)
76    __libelf_seterrno (ELF_E_NOMEM);
77  else
78    {
79      result->kind = kind;
80      result->ref_count = 1;
81      result->cmd = cmd;
82      result->fildes = fildes;
83      result->start_offset = offset;
84      result->maximum_size = maxsize;
85      result->map_address = map_address;
86      result->parent = parent;
87
88      rwlock_init (result->lock);
89    }
90
91  return result;
92}
93
94
95/* Acquire lock for the descriptor and all children.  */
96static void
97__attribute__ ((unused))
98libelf_acquire_all (Elf *elf)
99{
100  rwlock_wrlock (elf->lock);
101
102  if (elf->kind == ELF_K_AR)
103    {
104      Elf *child = elf->state.ar.children;
105
106      while (child != NULL)
107	{
108	  if (child->ref_count != 0)
109	    libelf_acquire_all (child);
110	  child = child->next;
111	}
112    }
113}
114
115/* Release own lock and those of the children.  */
116static void
117__attribute__ ((unused))
118libelf_release_all (Elf *elf)
119{
120  if (elf->kind == ELF_K_AR)
121    {
122      Elf *child = elf->state.ar.children;
123
124      while (child != NULL)
125	{
126	  if (child->ref_count != 0)
127	    libelf_release_all (child);
128	  child = child->next;
129	}
130    }
131
132  rwlock_unlock (elf->lock);
133}
134
135
136/* Macro to convert endianess in place.  It determines the function it
137   has to use itself.  */
138#define CONVERT(Var) \
139  (Var) = (sizeof (Var) == 1						      \
140	   ? (unsigned char) (Var)					      \
141	   : (sizeof (Var) == 2						      \
142	      ? bswap_16 (Var)						      \
143	      : (sizeof (Var) == 4					      \
144		 ? bswap_32 (Var)					      \
145		 : bswap_64 (Var))))
146
147#define CONVERT_TO(Dst, Var) \
148  (Dst) = (sizeof (Var) == 1						      \
149	   ? (unsigned char) (Var)					      \
150	   : (sizeof (Var) == 2						      \
151	      ? bswap_16 (Var)						      \
152	      : (sizeof (Var) == 4					      \
153		 ? bswap_32 (Var)					      \
154		 : bswap_64 (Var))))
155
156
157#if __BYTE_ORDER == __LITTLE_ENDIAN
158# define MY_ELFDATA	ELFDATA2LSB
159#else
160# define MY_ELFDATA	ELFDATA2MSB
161#endif
162
163#endif	/* common.h */
164