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 bfd_size_type amt; 88 89 /* Read in the ELF header in external format. */ 90 if (bfd_bread (&x_ehdr, sizeof (x_ehdr), abfd) != sizeof (x_ehdr)) 91 { 92 if (bfd_get_error () != bfd_error_system_call) 93 goto wrong; 94 else 95 goto fail; 96 } 97 98 /* Check the magic number. */ 99 if (! elf_file_p (&x_ehdr)) 100 goto wrong; 101 102 /* FIXME: Check EI_VERSION here ! */ 103 104 /* Check the address size ("class"). */ 105 if (x_ehdr.e_ident[EI_CLASS] != ELFCLASS) 106 goto wrong; 107 108 /* Check the byteorder. */ 109 switch (x_ehdr.e_ident[EI_DATA]) 110 { 111 case ELFDATA2MSB: /* Big-endian. */ 112 if (! bfd_big_endian (abfd)) 113 goto wrong; 114 break; 115 case ELFDATA2LSB: /* Little-endian. */ 116 if (! bfd_little_endian (abfd)) 117 goto wrong; 118 break; 119 default: 120 goto wrong; 121 } 122 123 /* Give abfd an elf_obj_tdata. */ 124 if (! (*abfd->xvec->_bfd_set_format[bfd_core]) (abfd)) 125 goto fail; 126 127 /* Swap in the rest of the header, now that we have the byte order. */ 128 i_ehdrp = elf_elfheader (abfd); 129 elf_swap_ehdr_in (abfd, &x_ehdr, i_ehdrp); 130 131 #if DEBUG & 1 132 elf_debug_file (i_ehdrp); 133 #endif 134 135 ebd = get_elf_backend_data (abfd); 136 137 /* Check that the ELF e_machine field matches what this particular 138 BFD format expects. */ 139 140 if (ebd->elf_machine_code != i_ehdrp->e_machine 141 && (ebd->elf_machine_alt1 == 0 142 || i_ehdrp->e_machine != ebd->elf_machine_alt1) 143 && (ebd->elf_machine_alt2 == 0 144 || i_ehdrp->e_machine != ebd->elf_machine_alt2)) 145 { 146 const bfd_target * const *target_ptr; 147 148 if (ebd->elf_machine_code != EM_NONE) 149 goto wrong; 150 151 /* This is the generic ELF target. Let it match any ELF target 152 for which we do not have a specific backend. */ 153 154 for (target_ptr = bfd_target_vector; *target_ptr != NULL; target_ptr++) 155 { 156 const struct elf_backend_data *back; 157 158 if ((*target_ptr)->flavour != bfd_target_elf_flavour) 159 continue; 160 back = xvec_get_elf_backend_data (*target_ptr); 161 if (back->s->arch_size != ARCH_SIZE) 162 continue; 163 if (back->elf_machine_code == i_ehdrp->e_machine 164 || (back->elf_machine_alt1 != 0 165 && i_ehdrp->e_machine == back->elf_machine_alt1) 166 || (back->elf_machine_alt2 != 0 167 && i_ehdrp->e_machine == back->elf_machine_alt2)) 168 { 169 /* target_ptr is an ELF backend which matches this 170 object file, so reject the generic ELF target. */ 171 goto wrong; 172 } 173 } 174 } 175 176 /* If there is no program header, or the type is not a core file, then 177 we are hosed. */ 178 if (i_ehdrp->e_phoff == 0 || i_ehdrp->e_type != ET_CORE) 179 goto wrong; 180 181 /* Does BFD's idea of the phdr size match the size 182 recorded in the file? */ 183 if (i_ehdrp->e_phentsize != sizeof (Elf_External_Phdr)) 184 goto wrong; 185 186 /* If the program header count is PN_XNUM(0xffff), the actual 187 count is in the first section header. */ 188 if (i_ehdrp->e_shoff != 0 && i_ehdrp->e_phnum == PN_XNUM) 189 { 190 Elf_External_Shdr x_shdr; 191 Elf_Internal_Shdr i_shdr; 192 bfd_signed_vma where = i_ehdrp->e_shoff; 193 194 if (where != (file_ptr) where) 195 goto wrong; 196 197 /* Seek to the section header table in the file. */ 198 if (bfd_seek (abfd, (file_ptr) where, SEEK_SET) != 0) 199 goto fail; 200 201 /* Read the first section header at index 0, and convert to internal 202 form. */ 203 if (bfd_bread (&x_shdr, sizeof (x_shdr), abfd) != sizeof (x_shdr)) 204 goto fail; 205 elf_swap_shdr_in (abfd, &x_shdr, &i_shdr); 206 207 if (i_shdr.sh_info != 0) 208 { 209 i_ehdrp->e_phnum = i_shdr.sh_info; 210 if (i_ehdrp->e_phnum != i_shdr.sh_info) 211 goto wrong; 212 } 213 } 214 215 /* Sanity check that we can read all of the program headers. 216 It ought to be good enough to just read the last one. */ 217 if (i_ehdrp->e_phnum > 1) 218 { 219 Elf_External_Phdr x_phdr; 220 Elf_Internal_Phdr i_phdr; 221 bfd_signed_vma where; 222 223 /* Check that we don't have a totally silly number of 224 program headers. */ 225 if (i_ehdrp->e_phnum > (unsigned int) -1 / sizeof (x_phdr) 226 || i_ehdrp->e_phnum > (unsigned int) -1 / sizeof (i_phdr)) 227 goto wrong; 228 229 where = i_ehdrp->e_phoff + (i_ehdrp->e_phnum - 1) * sizeof (x_phdr); 230 if (where != (file_ptr) where) 231 goto wrong; 232 if ((bfd_size_type) where <= i_ehdrp->e_phoff) 233 goto wrong; 234 235 if (bfd_seek (abfd, (file_ptr) where, SEEK_SET) != 0) 236 goto fail; 237 if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr)) 238 goto fail; 239 } 240 241 /* Move to the start of the program headers. */ 242 if (bfd_seek (abfd, (file_ptr) i_ehdrp->e_phoff, SEEK_SET) != 0) 243 goto wrong; 244 245 /* Allocate space for the program headers. */ 246 amt = sizeof (*i_phdrp) * i_ehdrp->e_phnum; 247 i_phdrp = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt); 248 if (!i_phdrp) 249 goto fail; 250 251 elf_tdata (abfd)->phdr = i_phdrp; 252 253 /* Read and convert to internal form. */ 254 for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) 255 { 256 Elf_External_Phdr x_phdr; 257 258 if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr)) 259 goto fail; 260 261 elf_swap_phdr_in (abfd, &x_phdr, i_phdrp + phindex); 262 } 263 264 /* Set the machine architecture. Do this before processing the 265 program headers since we need to know the architecture type 266 when processing the notes of some systems' core files. */ 267 if (! bfd_default_set_arch_mach (abfd, ebd->arch, 0) 268 /* It's OK if this fails for the generic target. */ 269 && ebd->elf_machine_code != EM_NONE) 270 goto fail; 271 272 /* Let the backend double check the format and override global 273 information. We do this before processing the program headers 274 to allow the correct machine (as opposed to just the default 275 machine) to be set, making it possible for grok_prstatus and 276 grok_psinfo to rely on the mach setting. */ 277 if (ebd->elf_backend_object_p != NULL 278 && ! ebd->elf_backend_object_p (abfd)) 279 goto wrong; 280 281 /* Process each program header. */ 282 for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) 283 if (! bfd_section_from_phdr (abfd, i_phdrp + phindex, (int) phindex)) 284 goto fail; 285 286 /* Check for core truncation. */ 287 { 288 bfd_size_type high = 0; 289 struct stat statbuf; 290 for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) 291 { 292 Elf_Internal_Phdr *p = i_phdrp + phindex; 293 if (p->p_filesz) 294 { 295 bfd_size_type current = p->p_offset + p->p_filesz; 296 if (high < current) 297 high = current; 298 } 299 } 300 if (bfd_stat (abfd, &statbuf) == 0) 301 { 302 if ((bfd_size_type) statbuf.st_size < high) 303 { 304 (*_bfd_error_handler) 305 (_("Warning: %B is truncated: expected core file " 306 "size >= %lu, found: %lu."), 307 abfd, (unsigned long) high, (unsigned long) statbuf.st_size); 308 } 309 } 310 } 311 312 /* Save the entry point from the ELF header. */ 313 bfd_get_start_address (abfd) = i_ehdrp->e_entry; 314 return abfd->xvec; 315 316 wrong: 317 bfd_set_error (bfd_error_wrong_format); 318 fail: 319 return NULL; 320 } 321