1 /* Decompression support for libdwfl: zlib (gzip) and/or bzlib (bzip2).
2 Copyright (C) 2009 Red Hat, Inc.
3 This file is part of Red Hat elfutils.
4
5 Red Hat elfutils is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by the
7 Free Software Foundation; version 2 of the License.
8
9 Red Hat elfutils is distributed in the hope that it will be useful, but
10 WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 General Public License for more details.
13
14 You should have received a copy of the GNU General Public License along
15 with Red Hat elfutils; if not, write to the Free Software Foundation,
16 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
17
18 In addition, as a special exception, Red Hat, Inc. gives You the
19 additional right to link the code of Red Hat elfutils with code licensed
20 under any Open Source Initiative certified open source license
21 (http://www.opensource.org/licenses/index.php) which requires the
22 distribution of source code with any binary distribution and to
23 distribute linked combinations of the two. Non-GPL Code permitted under
24 this exception must only link to the code of Red Hat elfutils through
25 those well defined interfaces identified in the file named EXCEPTION
26 found in the source code files (the "Approved Interfaces"). The files
27 of Non-GPL Code may instantiate templates or use macros or inline
28 functions from the Approved Interfaces without causing the resulting
29 work to be covered by the GNU General Public License. Only Red Hat,
30 Inc. may make changes or additions to the list of Approved Interfaces.
31 Red Hat's grant of this exception is conditioned upon your not adding
32 any new exceptions. If you wish to add a new Approved Interface or
33 exception, please contact Red Hat. You must obey the GNU General Public
34 License in all respects for all of the Red Hat elfutils code and other
35 code used in conjunction with Red Hat elfutils except the Non-GPL Code
36 covered by this exception. If you modify this file, you may extend this
37 exception to your version of the file, but you are not obligated to do
38 so. If you do not wish to provide this exception without modification,
39 you must delete this exception statement from your version and license
40 this file solely under the GPL without exception.
41
42 Red Hat elfutils is an included package of the Open Invention Network.
43 An included package of the Open Invention Network is a package for which
44 Open Invention Network licensees cross-license their patents. No patent
45 license is granted, either expressly or impliedly, by designation as an
46 included package. Should you wish to participate in the Open Invention
47 Network licensing program, please visit www.openinventionnetwork.com
48 <http://www.openinventionnetwork.com>. */
49
50 #include "../libelf/libelfP.h"
51 #undef _
52 #include "libdwflP.h"
53
54 #include <unistd.h>
55
56 #if !USE_ZLIB
57 # define __libdw_gunzip(...) false
58 #endif
59
60 #if !USE_BZLIB
61 # define __libdw_bunzip2(...) false
62 #endif
63
64 #if !USE_LZMA
65 # define __libdw_unlzma(...) false
66 #endif
67
68 /* Consumes and replaces *ELF only on success. */
69 static Dwfl_Error
decompress(int fd,Elf ** elf)70 decompress (int fd __attribute__ ((unused)), Elf **elf)
71 {
72 Dwfl_Error error = DWFL_E_BADELF;
73 void *buffer = NULL;
74 size_t size = 0;
75
76 #if USE_ZLIB || USE_BZLIB || USE_LZMA
77 const off64_t offset = (*elf)->start_offset;
78 void *const mapped = ((*elf)->map_address == NULL ? NULL
79 : (*elf)->map_address + offset);
80 const size_t mapped_size = (*elf)->maximum_size;
81 if (mapped_size == 0)
82 return error;
83
84 error = __libdw_gunzip (fd, offset, mapped, mapped_size, &buffer, &size);
85 if (error == DWFL_E_BADELF)
86 error = __libdw_bunzip2 (fd, offset, mapped, mapped_size, &buffer, &size);
87 if (error == DWFL_E_BADELF)
88 error = __libdw_unlzma (fd, offset, mapped, mapped_size, &buffer, &size);
89 #endif
90
91 if (error == DWFL_E_NOERROR)
92 {
93 if (unlikely (size == 0))
94 {
95 error = DWFL_E_BADELF;
96 free (buffer);
97 }
98 else
99 {
100 Elf *memelf = elf_memory (buffer, size);
101 if (memelf == NULL)
102 {
103 error = DWFL_E_LIBELF;
104 free (buffer);
105 }
106 else
107 {
108 memelf->flags |= ELF_F_MALLOCED;
109 elf_end (*elf);
110 *elf = memelf;
111 }
112 }
113 }
114 else
115 free (buffer);
116
117 return error;
118 }
119
120 static Dwfl_Error
what_kind(int fd,Elf ** elfp,Elf_Kind * kind,bool * close_fd)121 what_kind (int fd, Elf **elfp, Elf_Kind *kind, bool *close_fd)
122 {
123 Dwfl_Error error = DWFL_E_NOERROR;
124 *kind = elf_kind (*elfp);
125 if (unlikely (*kind == ELF_K_NONE))
126 {
127 if (unlikely (*elfp == NULL))
128 error = DWFL_E_LIBELF;
129 else
130 {
131 error = decompress (fd, elfp);
132 if (error == DWFL_E_NOERROR)
133 {
134 *close_fd = true;
135 *kind = elf_kind (*elfp);
136 }
137 }
138 }
139 return error;
140 }
141
142 Dwfl_Error internal_function
__libdw_open_file(int * fdp,Elf ** elfp,bool close_on_fail,bool archive_ok)143 __libdw_open_file (int *fdp, Elf **elfp, bool close_on_fail, bool archive_ok)
144 {
145 bool close_fd = false;
146
147 Elf *elf = elf_begin (*fdp, ELF_C_READ_MMAP_PRIVATE, NULL);
148
149 Elf_Kind kind;
150 Dwfl_Error error = what_kind (*fdp, &elf, &kind, &close_fd);
151 if (error == DWFL_E_BADELF)
152 {
153 /* It's not an ELF file or a compressed file.
154 See if it's an image with a header preceding the real file. */
155
156 off64_t offset = elf->start_offset;
157 error = __libdw_image_header (*fdp, &offset,
158 (elf->map_address == NULL ? NULL
159 : elf->map_address + offset),
160 elf->maximum_size);
161 if (error == DWFL_E_NOERROR)
162 {
163 /* Pure evil. libelf needs some better interfaces. */
164 elf->kind = ELF_K_AR;
165 elf->state.ar.elf_ar_hdr.ar_name = "libdwfl is faking you out";
166 elf->state.ar.elf_ar_hdr.ar_size = elf->maximum_size - offset;
167 elf->state.ar.offset = offset - sizeof (struct ar_hdr);
168 Elf *subelf = elf_begin (-1, ELF_C_READ_MMAP_PRIVATE, elf);
169 elf->kind = ELF_K_NONE;
170 if (unlikely (subelf == NULL))
171 error = DWFL_E_LIBELF;
172 else
173 {
174 subelf->parent = NULL;
175 subelf->flags |= elf->flags & (ELF_F_MMAPPED | ELF_F_MALLOCED);
176 elf->flags &= ~(ELF_F_MMAPPED | ELF_F_MALLOCED);
177 elf_end (elf);
178 elf = subelf;
179 error = what_kind (*fdp, &elf, &kind, &close_fd);
180 }
181 }
182 }
183
184 if (error == DWFL_E_NOERROR
185 && kind != ELF_K_ELF
186 && !(archive_ok && kind == ELF_K_AR))
187 error = DWFL_E_BADELF;
188
189 if (error != DWFL_E_NOERROR)
190 {
191 elf_end (elf);
192 elf = NULL;
193 }
194
195 if (error == DWFL_E_NOERROR ? close_fd : close_on_fail)
196 {
197 close (*fdp);
198 *fdp = -1;
199 }
200
201 *elfp = elf;
202 return error;
203 }
204