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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 
62 static inline Elf_Kind
63 __attribute__ ((unused))
determine_kind(void * buf,size_t len)64 determine_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.  */
90 static inline Elf *
91 __attribute__ ((unused))
allocate_elf(int fildes,void * map_address,off_t offset,size_t maxsize,Elf_Cmd cmd,Elf * parent,Elf_Kind kind,size_t extra)92 allocate_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.  */
117 static void
118 __attribute__ ((unused))
libelf_acquire_all(Elf * elf)119 libelf_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.  */
137 static void
138 __attribute__ ((unused))
libelf_release_all(Elf * elf)139 libelf_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