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 <stdlib.h>
34 #include <string.h>
35
36 #include "libelfP.h"
37
38 static inline Elf_Kind
39 __attribute__ ((unused))
determine_kind(void * buf,size_t len)40 determine_kind (void *buf, size_t len)
41 {
42 /* First test for an archive. */
43 if (len >= SARMAG && memcmp (buf, ARMAG, SARMAG) == 0)
44 return ELF_K_AR;
45
46 /* Next try ELF files. */
47 if (len >= EI_NIDENT && memcmp (buf, ELFMAG, SELFMAG) == 0)
48 {
49 /* Could be an ELF file. */
50 int eclass = (int) ((unsigned char *) buf)[EI_CLASS];
51 int data = (int) ((unsigned char *) buf)[EI_DATA];
52 int version = (int) ((unsigned char *) buf)[EI_VERSION];
53
54 if (eclass > ELFCLASSNONE && eclass < ELFCLASSNUM
55 && data > ELFDATANONE && data < ELFDATANUM
56 && version == EV_CURRENT)
57 return ELF_K_ELF;
58 }
59
60 /* We do not know this file type. */
61 return ELF_K_NONE;
62 }
63
64
65 /* Allocate an Elf descriptor and fill in the generic information. */
66 static inline Elf *
67 __attribute__ ((unused))
allocate_elf(int fildes,void * map_address,int64_t offset,size_t maxsize,Elf_Cmd cmd,Elf * parent,Elf_Kind kind,size_t extra)68 allocate_elf (int fildes, void *map_address, int64_t offset, size_t maxsize,
69 Elf_Cmd cmd, Elf *parent, Elf_Kind kind, size_t extra)
70 {
71 Elf *result = calloc (1, sizeof (Elf) + extra);
72 if (result == NULL)
73 __libelf_seterrno (ELF_E_NOMEM);
74 else
75 {
76 result->kind = kind;
77 result->ref_count = 1;
78 result->cmd = cmd;
79 result->fildes = fildes;
80 result->start_offset = offset;
81 result->maximum_size = maxsize;
82 result->map_address = map_address;
83 result->parent = parent;
84
85 rwlock_init (result->lock);
86 }
87
88 return result;
89 }
90
91
92 /* Acquire lock for the descriptor and all children. */
93 static void
94 __attribute__ ((unused))
libelf_acquire_all(Elf * elf)95 libelf_acquire_all (Elf *elf)
96 {
97 rwlock_wrlock (elf->lock);
98
99 if (elf->kind == ELF_K_AR)
100 {
101 Elf *child = elf->state.ar.children;
102
103 while (child != NULL)
104 {
105 if (child->ref_count != 0)
106 libelf_acquire_all (child);
107 child = child->next;
108 }
109 }
110 }
111
112 /* Release own lock and those of the children. */
113 static void
114 __attribute__ ((unused))
libelf_release_all(Elf * elf)115 libelf_release_all (Elf *elf)
116 {
117 if (elf->kind == ELF_K_AR)
118 {
119 Elf *child = elf->state.ar.children;
120
121 while (child != NULL)
122 {
123 if (child->ref_count != 0)
124 libelf_release_all (child);
125 child = child->next;
126 }
127 }
128
129 rwlock_unlock (elf->lock);
130 }
131
132
133 /* Macro to convert endianness in place. It determines the function it
134 has to use itself. */
135 #define CONVERT(Var) \
136 (Var) = (sizeof (Var) == 1 \
137 ? (unsigned char) (Var) \
138 : (sizeof (Var) == 2 \
139 ? bswap_16 (Var) \
140 : (sizeof (Var) == 4 \
141 ? bswap_32 (Var) \
142 : bswap_64 (Var))))
143
144 #define CONVERT_TO(Dst, Var) \
145 (Dst) = (sizeof (Var) == 1 \
146 ? (unsigned char) (Var) \
147 : (sizeof (Var) == 2 \
148 ? bswap_16 (Var) \
149 : (sizeof (Var) == 4 \
150 ? bswap_32 (Var) \
151 : bswap_64 (Var))))
152
153
154 #if BYTE_ORDER == LITTLE_ENDIAN
155 # define MY_ELFDATA ELFDATA2LSB
156 #else
157 # define MY_ELFDATA ELFDATA2MSB
158 #endif
159
160 #endif /* common.h */
161