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
41 static inline Elf_Kind
42 __attribute__ ((unused))
determine_kind(void * buf,size_t len)43 determine_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. */
69 static inline Elf *
70 __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)71 allocate_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. */
96 static void
97 __attribute__ ((unused))
libelf_acquire_all(Elf * elf)98 libelf_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. */
116 static void
117 __attribute__ ((unused))
libelf_release_all(Elf * elf)118 libelf_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