1 /* ELF core file support for BFD. 2 Copyright 1995, 1996, 1997, 1998, 2000, 2001, 2002, 2003, 2005, 2007, 3 2008, 2010 Free Software Foundation, Inc. 4 5 This file is part of BFD, the Binary File Descriptor library. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; if not, write to the Free Software 19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 20 MA 02110-1301, USA. */ 21 22 char* 23 elf_core_file_failing_command (bfd *abfd) 24 { 25 return elf_tdata (abfd)->core_command; 26 } 27 28 int 29 elf_core_file_failing_signal (bfd *abfd) 30 { 31 return elf_tdata (abfd)->core_signal; 32 } 33 34 int 35 elf_core_file_pid (bfd *abfd) 36 { 37 return elf_tdata (abfd)->core_pid; 38 } 39 40 bfd_boolean 41 elf_core_file_matches_executable_p (bfd *core_bfd, bfd *exec_bfd) 42 { 43 char* corename; 44 45 /* xvecs must match if both are ELF files for the same target. */ 46 47 if (core_bfd->xvec != exec_bfd->xvec) 48 { 49 bfd_set_error (bfd_error_system_call); 50 return FALSE; 51 } 52 53 /* See if the name in the corefile matches the executable name. */ 54 corename = elf_tdata (core_bfd)->core_program; 55 if (corename != NULL) 56 { 57 const char* execname = strrchr (exec_bfd->filename, '/'); 58 59 execname = execname ? execname + 1 : exec_bfd->filename; 60 61 if (strcmp (execname, corename) != 0) 62 return FALSE; 63 } 64 65 return TRUE; 66 } 67 68 /* Core files are simply standard ELF formatted files that partition 69 the file using the execution view of the file (program header table) 70 rather than the linking view. In fact, there is no section header 71 table in a core file. 72 73 The process status information (including the contents of the general 74 register set) and the floating point register set are stored in a 75 segment of type PT_NOTE. We handcraft a couple of extra bfd sections 76 that allow standard bfd access to the general registers (.reg) and the 77 floating point registers (.reg2). */ 78 79 const bfd_target * 80 elf_core_file_p (bfd *abfd) 81 { 82 Elf_External_Ehdr x_ehdr; /* Elf file header, external form. */ 83 Elf_Internal_Ehdr *i_ehdrp; /* Elf file header, internal form. */ 84 Elf_Internal_Phdr *i_phdrp; /* Elf program header, internal form. */ 85 unsigned int phindex; 86 const struct elf_backend_data *ebd; 87 struct bfd_preserve preserve; 88 bfd_size_type amt; 89 90 preserve.marker = NULL; 91 92 /* Read in the ELF header in external format. */ 93 if (bfd_bread (&x_ehdr, sizeof (x_ehdr), abfd) != sizeof (x_ehdr)) 94 { 95 if (bfd_get_error () != bfd_error_system_call) 96 goto wrong; 97 else 98 goto fail; 99 } 100 101 /* Check the magic number. */ 102 if (! elf_file_p (&x_ehdr)) 103 goto wrong; 104 105 /* FIXME: Check EI_VERSION here ! */ 106 107 /* Check the address size ("class"). */ 108 if (x_ehdr.e_ident[EI_CLASS] != ELFCLASS) 109 goto wrong; 110 111 /* Check the byteorder. */ 112 switch (x_ehdr.e_ident[EI_DATA]) 113 { 114 case ELFDATA2MSB: /* Big-endian. */ 115 if (! bfd_big_endian (abfd)) 116 goto wrong; 117 break; 118 case ELFDATA2LSB: /* Little-endian. */ 119 if (! bfd_little_endian (abfd)) 120 goto wrong; 121 break; 122 default: 123 goto wrong; 124 } 125 126 if (!bfd_preserve_save (abfd, &preserve)) 127 goto fail; 128 129 /* Give abfd an elf_obj_tdata. */ 130 if (! (*abfd->xvec->_bfd_set_format[bfd_core]) (abfd)) 131 goto fail; 132 preserve.marker = elf_tdata (abfd); 133 134 /* Swap in the rest of the header, now that we have the byte order. */ 135 i_ehdrp = elf_elfheader (abfd); 136 elf_swap_ehdr_in (abfd, &x_ehdr, i_ehdrp); 137 138 #if DEBUG & 1 139 elf_debug_file (i_ehdrp); 140 #endif 141 142 ebd = get_elf_backend_data (abfd); 143 144 /* Check that the ELF e_machine field matches what this particular 145 BFD format expects. */ 146 147 if (ebd->elf_machine_code != i_ehdrp->e_machine 148 && (ebd->elf_machine_alt1 == 0 149 || i_ehdrp->e_machine != ebd->elf_machine_alt1) 150 && (ebd->elf_machine_alt2 == 0 151 || i_ehdrp->e_machine != ebd->elf_machine_alt2)) 152 { 153 const bfd_target * const *target_ptr; 154 155 if (ebd->elf_machine_code != EM_NONE) 156 goto wrong; 157 158 /* This is the generic ELF target. Let it match any ELF target 159 for which we do not have a specific backend. */ 160 161 for (target_ptr = bfd_target_vector; *target_ptr != NULL; target_ptr++) 162 { 163 const struct elf_backend_data *back; 164 165 if ((*target_ptr)->flavour != bfd_target_elf_flavour) 166 continue; 167 back = xvec_get_elf_backend_data (*target_ptr); 168 if (back->s->arch_size != ARCH_SIZE) 169 continue; 170 if (back->elf_machine_code == i_ehdrp->e_machine 171 || (back->elf_machine_alt1 != 0 172 && i_ehdrp->e_machine == back->elf_machine_alt1) 173 || (back->elf_machine_alt2 != 0 174 && i_ehdrp->e_machine == back->elf_machine_alt2)) 175 { 176 /* target_ptr is an ELF backend which matches this 177 object file, so reject the generic ELF target. */ 178 goto wrong; 179 } 180 } 181 } 182 183 /* If there is no program header, or the type is not a core file, then 184 we are hosed. */ 185 if (i_ehdrp->e_phoff == 0 || i_ehdrp->e_type != ET_CORE) 186 goto wrong; 187 188 /* Does BFD's idea of the phdr size match the size 189 recorded in the file? */ 190 if (i_ehdrp->e_phentsize != sizeof (Elf_External_Phdr)) 191 goto wrong; 192 193 /* If the program header count is PN_XNUM(0xffff), the actual 194 count is in the first section header. */ 195 if (i_ehdrp->e_shoff != 0 && i_ehdrp->e_phnum == PN_XNUM) 196 { 197 Elf_External_Shdr x_shdr; 198 Elf_Internal_Shdr i_shdr; 199 bfd_signed_vma where = i_ehdrp->e_shoff; 200 201 if (where != (file_ptr) where) 202 goto wrong; 203 204 /* Seek to the section header table in the file. */ 205 if (bfd_seek (abfd, (file_ptr) where, SEEK_SET) != 0) 206 goto fail; 207 208 /* Read the first section header at index 0, and convert to internal 209 form. */ 210 if (bfd_bread (&x_shdr, sizeof (x_shdr), abfd) != sizeof (x_shdr)) 211 goto fail; 212 elf_swap_shdr_in (abfd, &x_shdr, &i_shdr); 213 214 if (i_shdr.sh_info != 0) 215 { 216 i_ehdrp->e_phnum = i_shdr.sh_info; 217 if (i_ehdrp->e_phnum != i_shdr.sh_info) 218 goto wrong; 219 } 220 } 221 222 /* Sanity check that we can read all of the program headers. 223 It ought to be good enough to just read the last one. */ 224 if (i_ehdrp->e_phnum > 1) 225 { 226 Elf_External_Phdr x_phdr; 227 Elf_Internal_Phdr i_phdr; 228 bfd_signed_vma where; 229 230 /* Check that we don't have a totally silly number of 231 program headers. */ 232 if (i_ehdrp->e_phnum > (unsigned int) -1 / sizeof (x_phdr) 233 || i_ehdrp->e_phnum > (unsigned int) -1 / sizeof (i_phdr)) 234 goto wrong; 235 236 where = i_ehdrp->e_phoff + (i_ehdrp->e_phnum - 1) * sizeof (x_phdr); 237 if (where != (file_ptr) where) 238 goto wrong; 239 if ((bfd_size_type) where <= i_ehdrp->e_phoff) 240 goto wrong; 241 242 if (bfd_seek (abfd, (file_ptr) where, SEEK_SET) != 0) 243 goto fail; 244 if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr)) 245 goto fail; 246 } 247 248 /* Move to the start of the program headers. */ 249 if (bfd_seek (abfd, (file_ptr) i_ehdrp->e_phoff, SEEK_SET) != 0) 250 goto wrong; 251 252 /* Allocate space for the program headers. */ 253 amt = sizeof (*i_phdrp) * i_ehdrp->e_phnum; 254 i_phdrp = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt); 255 if (!i_phdrp) 256 goto fail; 257 258 elf_tdata (abfd)->phdr = i_phdrp; 259 260 /* Read and convert to internal form. */ 261 for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) 262 { 263 Elf_External_Phdr x_phdr; 264 265 if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr)) 266 goto fail; 267 268 elf_swap_phdr_in (abfd, &x_phdr, i_phdrp + phindex); 269 } 270 271 /* Set the machine architecture. Do this before processing the 272 program headers since we need to know the architecture type 273 when processing the notes of some systems' core files. */ 274 if (! bfd_default_set_arch_mach (abfd, ebd->arch, 0) 275 /* It's OK if this fails for the generic target. */ 276 && ebd->elf_machine_code != EM_NONE) 277 goto fail; 278 279 /* Let the backend double check the format and override global 280 information. We do this before processing the program headers 281 to allow the correct machine (as opposed to just the default 282 machine) to be set, making it possible for grok_prstatus and 283 grok_psinfo to rely on the mach setting. */ 284 if (ebd->elf_backend_object_p != NULL 285 && ! ebd->elf_backend_object_p (abfd)) 286 goto wrong; 287 288 /* Process each program header. */ 289 for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) 290 if (! bfd_section_from_phdr (abfd, i_phdrp + phindex, (int) phindex)) 291 goto fail; 292 293 /* Check for core truncation. */ 294 { 295 bfd_size_type high = 0; 296 struct stat statbuf; 297 for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) 298 { 299 Elf_Internal_Phdr *p = i_phdrp + phindex; 300 if (p->p_filesz) 301 { 302 bfd_size_type current = p->p_offset + p->p_filesz; 303 if (high < current) 304 high = current; 305 } 306 } 307 if (bfd_stat (abfd, &statbuf) == 0) 308 { 309 if ((bfd_size_type) statbuf.st_size < high) 310 { 311 (*_bfd_error_handler) 312 (_("Warning: %B is truncated: expected core file " 313 "size >= %lu, found: %lu."), 314 abfd, (unsigned long) high, (unsigned long) statbuf.st_size); 315 } 316 } 317 } 318 319 /* Save the entry point from the ELF header. */ 320 bfd_get_start_address (abfd) = i_ehdrp->e_entry; 321 322 bfd_preserve_finish (abfd, &preserve); 323 return abfd->xvec; 324 325 wrong: 326 /* There is way too much undoing of half-known state here. The caller, 327 bfd_check_format_matches, really shouldn't iterate on live bfd's to 328 check match/no-match like it does. We have to rely on that a call to 329 bfd_default_set_arch_mach with the previously known mach, undoes what 330 was done by the first bfd_default_set_arch_mach (with mach 0) here. 331 For this to work, only elf-data and the mach may be changed by the 332 target-specific elf_backend_object_p function. Note that saving the 333 whole bfd here and restoring it would be even worse; the first thing 334 you notice is that the cached bfd file position gets out of sync. */ 335 bfd_set_error (bfd_error_wrong_format); 336 337 fail: 338 if (preserve.marker != NULL) 339 bfd_preserve_restore (abfd, &preserve); 340 return NULL; 341 } 342