1 /* Decompression support for libdwfl: zlib (gzip), bzlib (bzip2) or lzma (xz). 2 Copyright (C) 2009, 2016 Red Hat, Inc. 3 This file is part of elfutils. 4 5 This file is free software; you can redistribute it and/or modify 6 it under the terms of either 7 8 * the GNU Lesser General Public License as published by the Free 9 Software Foundation; either version 3 of the License, or (at 10 your option) any later version 11 12 or 13 14 * the GNU General Public License as published by the Free 15 Software Foundation; either version 2 of the License, or (at 16 your option) any later version 17 18 or both in parallel, as here. 19 20 elfutils is distributed in the hope that it will be useful, but 21 WITHOUT ANY WARRANTY; without even the implied warranty of 22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 23 General Public License for more details. 24 25 You should have received copies of the GNU General Public License and 26 the GNU Lesser General Public License along with this program. If 27 not, see <http://www.gnu.org/licenses/>. */ 28 29 #include "../libelf/libelfP.h" 30 #undef _ 31 #include "libdwflP.h" 32 33 #include <unistd.h> 34 35 #if !USE_BZLIB 36 # define __libdw_bunzip2(...) DWFL_E_BADELF 37 #endif 38 39 #if !USE_LZMA 40 # define __libdw_unlzma(...) DWFL_E_BADELF 41 #endif 42 43 /* Consumes and replaces *ELF only on success. */ 44 static Dwfl_Error 45 decompress (int fd __attribute__ ((unused)), Elf **elf) 46 { 47 Dwfl_Error error = DWFL_E_BADELF; 48 void *buffer = NULL; 49 size_t size = 0; 50 51 const off_t offset = (*elf)->start_offset; 52 void *const mapped = ((*elf)->map_address == NULL ? NULL 53 : (*elf)->map_address + offset); 54 const size_t mapped_size = (*elf)->maximum_size; 55 if (mapped_size == 0) 56 return error; 57 58 error = __libdw_gunzip (fd, offset, mapped, mapped_size, &buffer, &size); 59 if (error == DWFL_E_BADELF) 60 error = __libdw_bunzip2 (fd, offset, mapped, mapped_size, &buffer, &size); 61 if (error == DWFL_E_BADELF) 62 error = __libdw_unlzma (fd, offset, mapped, mapped_size, &buffer, &size); 63 64 if (error == DWFL_E_NOERROR) 65 { 66 if (unlikely (size == 0)) 67 { 68 error = DWFL_E_BADELF; 69 free (buffer); 70 } 71 else 72 { 73 Elf *memelf = elf_memory (buffer, size); 74 if (memelf == NULL) 75 { 76 error = DWFL_E_LIBELF; 77 free (buffer); 78 } 79 else 80 { 81 memelf->flags |= ELF_F_MALLOCED; 82 elf_end (*elf); 83 *elf = memelf; 84 } 85 } 86 } 87 else 88 free (buffer); 89 90 return error; 91 } 92 93 static Dwfl_Error 94 what_kind (int fd, Elf **elfp, Elf_Kind *kind, bool *close_fd) 95 { 96 Dwfl_Error error = DWFL_E_NOERROR; 97 *kind = elf_kind (*elfp); 98 if (unlikely (*kind == ELF_K_NONE)) 99 { 100 if (unlikely (*elfp == NULL)) 101 error = DWFL_E_LIBELF; 102 else 103 { 104 error = decompress (fd, elfp); 105 if (error == DWFL_E_NOERROR) 106 { 107 *close_fd = true; 108 *kind = elf_kind (*elfp); 109 } 110 } 111 } 112 return error; 113 } 114 115 Dwfl_Error internal_function 116 __libdw_open_file (int *fdp, Elf **elfp, bool close_on_fail, bool archive_ok) 117 { 118 bool close_fd = false; 119 120 Elf *elf = elf_begin (*fdp, ELF_C_READ_MMAP_PRIVATE, NULL); 121 122 Elf_Kind kind; 123 Dwfl_Error error = what_kind (*fdp, &elf, &kind, &close_fd); 124 if (error == DWFL_E_BADELF) 125 { 126 /* It's not an ELF file or a compressed file. 127 See if it's an image with a header preceding the real file. */ 128 129 off_t offset = elf->start_offset; 130 error = __libdw_image_header (*fdp, &offset, 131 (elf->map_address == NULL ? NULL 132 : elf->map_address + offset), 133 elf->maximum_size); 134 if (error == DWFL_E_NOERROR) 135 { 136 /* Pure evil. libelf needs some better interfaces. */ 137 elf->kind = ELF_K_AR; 138 elf->state.ar.elf_ar_hdr.ar_name = "libdwfl is faking you out"; 139 elf->state.ar.elf_ar_hdr.ar_size = elf->maximum_size - offset; 140 elf->state.ar.offset = offset - sizeof (struct ar_hdr); 141 Elf *subelf = elf_begin (-1, ELF_C_READ_MMAP_PRIVATE, elf); 142 elf->kind = ELF_K_NONE; 143 if (unlikely (subelf == NULL)) 144 error = DWFL_E_LIBELF; 145 else 146 { 147 subelf->parent = NULL; 148 subelf->flags |= elf->flags & (ELF_F_MMAPPED | ELF_F_MALLOCED); 149 elf->flags &= ~(ELF_F_MMAPPED | ELF_F_MALLOCED); 150 elf_end (elf); 151 elf = subelf; 152 error = what_kind (*fdp, &elf, &kind, &close_fd); 153 } 154 } 155 } 156 157 if (error == DWFL_E_NOERROR 158 && kind != ELF_K_ELF 159 && !(archive_ok && kind == ELF_K_AR)) 160 error = DWFL_E_BADELF; 161 162 if (error != DWFL_E_NOERROR) 163 { 164 elf_end (elf); 165 elf = NULL; 166 } 167 168 if (error == DWFL_E_NOERROR ? close_fd : close_on_fail) 169 { 170 close (*fdp); 171 *fdp = -1; 172 } 173 174 *elfp = elf; 175 return error; 176 } 177
