1 /* ELF core file support for BFD. 2 Copyright (C) 1995-2016 Free Software Foundation, Inc. 3 4 This file is part of BFD, the Binary File Descriptor library. 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3 of the License, or 9 (at your option) any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program; if not, write to the Free Software 18 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 19 MA 02110-1301, USA. */ 20 21 char* 22 elf_core_file_failing_command (bfd *abfd) 23 { 24 return elf_tdata (abfd)->core->command; 25 } 26 27 int 28 elf_core_file_failing_signal (bfd *abfd) 29 { 30 return elf_tdata (abfd)->core->signal; 31 } 32 33 int 34 elf_core_file_pid (bfd *abfd) 35 { 36 return elf_tdata (abfd)->core->pid; 37 } 38 39 bfd_boolean 40 elf_core_file_matches_executable_p (bfd *core_bfd, bfd *exec_bfd) 41 { 42 char* corename; 43 44 /* xvecs must match if both are ELF files for the same target. */ 45 46 if (core_bfd->xvec != exec_bfd->xvec) 47 { 48 bfd_set_error (bfd_error_system_call); 49 return FALSE; 50 } 51 52 /* See if the name in the corefile matches the executable name. */ 53 corename = elf_tdata (core_bfd)->core->program; 54 if (corename != NULL) 55 { 56 const char* execname = strrchr (exec_bfd->filename, '/'); 57 58 execname = execname ? execname + 1 : exec_bfd->filename; 59 60 if (strcmp (execname, corename) != 0) 61 return FALSE; 62 } 63 64 return TRUE; 65 } 66 67 /* Core files are simply standard ELF formatted files that partition 68 the file using the execution view of the file (program header table) 69 rather than the linking view. In fact, there is no section header 70 table in a core file. 71 72 The process status information (including the contents of the general 73 register set) and the floating point register set are stored in a 74 segment of type PT_NOTE. We handcraft a couple of extra bfd sections 75 that allow standard bfd access to the general registers (.reg) and the 76 floating point registers (.reg2). */ 77 78 const bfd_target * 79 elf_core_file_p (bfd *abfd) 80 { 81 Elf_External_Ehdr x_ehdr; /* Elf file header, external form. */ 82 Elf_Internal_Ehdr *i_ehdrp; /* Elf file header, internal form. */ 83 Elf_Internal_Phdr *i_phdrp; /* Elf program header, internal form. */ 84 unsigned int phindex; 85 const struct elf_backend_data *ebd; 86 bfd_size_type amt; 87 88 /* Read in the ELF header in external format. */ 89 if (bfd_bread (&x_ehdr, sizeof (x_ehdr), abfd) != sizeof (x_ehdr)) 90 { 91 if (bfd_get_error () != bfd_error_system_call) 92 goto wrong; 93 else 94 goto fail; 95 } 96 97 /* Check the magic number. */ 98 if (! elf_file_p (&x_ehdr)) 99 goto wrong; 100 101 /* FIXME: Check EI_VERSION here ! */ 102 103 /* Check the address size ("class"). */ 104 if (x_ehdr.e_ident[EI_CLASS] != ELFCLASS) 105 goto wrong; 106 107 /* Check the byteorder. */ 108 switch (x_ehdr.e_ident[EI_DATA]) 109 { 110 case ELFDATA2MSB: /* Big-endian. */ 111 if (! bfd_big_endian (abfd)) 112 goto wrong; 113 break; 114 case ELFDATA2LSB: /* Little-endian. */ 115 if (! bfd_little_endian (abfd)) 116 goto wrong; 117 break; 118 default: 119 goto wrong; 120 } 121 122 /* Give abfd an elf_obj_tdata. */ 123 if (! (*abfd->xvec->_bfd_set_format[bfd_core]) (abfd)) 124 goto fail; 125 126 /* Swap in the rest of the header, now that we have the byte order. */ 127 i_ehdrp = elf_elfheader (abfd); 128 elf_swap_ehdr_in (abfd, &x_ehdr, i_ehdrp); 129 130 #if DEBUG & 1 131 elf_debug_file (i_ehdrp); 132 #endif 133 134 ebd = get_elf_backend_data (abfd); 135 136 /* Check that the ELF e_machine field matches what this particular 137 BFD format expects. */ 138 139 if (ebd->elf_machine_code != i_ehdrp->e_machine 140 && (ebd->elf_machine_alt1 == 0 141 || i_ehdrp->e_machine != ebd->elf_machine_alt1) 142 && (ebd->elf_machine_alt2 == 0 143 || i_ehdrp->e_machine != ebd->elf_machine_alt2)) 144 { 145 const bfd_target * const *target_ptr; 146 147 if (ebd->elf_machine_code != EM_NONE) 148 goto wrong; 149 150 /* This is the generic ELF target. Let it match any ELF target 151 for which we do not have a specific backend. */ 152 153 for (target_ptr = bfd_target_vector; *target_ptr != NULL; target_ptr++) 154 { 155 const struct elf_backend_data *back; 156 157 if ((*target_ptr)->flavour != bfd_target_elf_flavour) 158 continue; 159 back = xvec_get_elf_backend_data (*target_ptr); 160 if (back->s->arch_size != ARCH_SIZE) 161 continue; 162 if (back->elf_machine_code == i_ehdrp->e_machine 163 || (back->elf_machine_alt1 != 0 164 && i_ehdrp->e_machine == back->elf_machine_alt1) 165 || (back->elf_machine_alt2 != 0 166 && i_ehdrp->e_machine == back->elf_machine_alt2)) 167 { 168 /* target_ptr is an ELF backend which matches this 169 object file, so reject the generic ELF target. */ 170 goto wrong; 171 } 172 } 173 } 174 175 /* If there is no program header, or the type is not a core file, then 176 we are hosed. */ 177 if (i_ehdrp->e_phoff == 0 || i_ehdrp->e_type != ET_CORE) 178 goto wrong; 179 180 /* Does BFD's idea of the phdr size match the size 181 recorded in the file? */ 182 if (i_ehdrp->e_phentsize != sizeof (Elf_External_Phdr)) 183 goto wrong; 184 185 /* If the program header count is PN_XNUM(0xffff), the actual 186 count is in the first section header. */ 187 if (i_ehdrp->e_shoff != 0 && i_ehdrp->e_phnum == PN_XNUM) 188 { 189 Elf_External_Shdr x_shdr; 190 Elf_Internal_Shdr i_shdr; 191 file_ptr where = (file_ptr) i_ehdrp->e_shoff; 192 193 /* Seek to the section header table in the file. */ 194 if (bfd_seek (abfd, where, SEEK_SET) != 0) 195 goto fail; 196 197 /* Read the first section header at index 0, and convert to internal 198 form. */ 199 if (bfd_bread (&x_shdr, sizeof (x_shdr), abfd) != sizeof (x_shdr)) 200 goto fail; 201 elf_swap_shdr_in (abfd, &x_shdr, &i_shdr); 202 203 if (i_shdr.sh_info != 0) 204 { 205 i_ehdrp->e_phnum = i_shdr.sh_info; 206 if (i_ehdrp->e_phnum != i_shdr.sh_info) 207 goto wrong; 208 } 209 } 210 211 /* Sanity check that we can read all of the program headers. 212 It ought to be good enough to just read the last one. */ 213 if (i_ehdrp->e_phnum > 1) 214 { 215 Elf_External_Phdr x_phdr; 216 Elf_Internal_Phdr i_phdr; 217 file_ptr where; 218 219 /* Check that we don't have a totally silly number of 220 program headers. */ 221 if (i_ehdrp->e_phnum > (unsigned int) -1 / sizeof (x_phdr) 222 || i_ehdrp->e_phnum > (unsigned int) -1 / sizeof (i_phdr)) 223 goto wrong; 224 225 where = (file_ptr)(i_ehdrp->e_phoff + (i_ehdrp->e_phnum - 1) * sizeof (x_phdr)); 226 if ((bfd_size_type) where <= i_ehdrp->e_phoff) 227 goto wrong; 228 229 if (bfd_seek (abfd, where, SEEK_SET) != 0) 230 goto fail; 231 if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr)) 232 goto fail; 233 } 234 235 /* Move to the start of the program headers. */ 236 if (bfd_seek (abfd, (file_ptr) i_ehdrp->e_phoff, SEEK_SET) != 0) 237 goto wrong; 238 239 /* Allocate space for the program headers. */ 240 amt = sizeof (*i_phdrp) * i_ehdrp->e_phnum; 241 i_phdrp = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt); 242 if (!i_phdrp) 243 goto fail; 244 245 elf_tdata (abfd)->phdr = i_phdrp; 246 247 /* Read and convert to internal form. */ 248 for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) 249 { 250 Elf_External_Phdr x_phdr; 251 252 if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr)) 253 goto fail; 254 255 elf_swap_phdr_in (abfd, &x_phdr, i_phdrp + phindex); 256 } 257 258 /* Set the machine architecture. Do this before processing the 259 program headers since we need to know the architecture type 260 when processing the notes of some systems' core files. */ 261 if (! bfd_default_set_arch_mach (abfd, ebd->arch, 0) 262 /* It's OK if this fails for the generic target. */ 263 && ebd->elf_machine_code != EM_NONE) 264 goto fail; 265 266 /* Let the backend double check the format and override global 267 information. We do this before processing the program headers 268 to allow the correct machine (as opposed to just the default 269 machine) to be set, making it possible for grok_prstatus and 270 grok_psinfo to rely on the mach setting. */ 271 if (ebd->elf_backend_object_p != NULL 272 && ! ebd->elf_backend_object_p (abfd)) 273 goto wrong; 274 275 /* Process each program header. */ 276 for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) 277 if (! bfd_section_from_phdr (abfd, i_phdrp + phindex, (int) phindex)) 278 goto fail; 279 280 /* Check for core truncation. */ 281 { 282 bfd_size_type high = 0; 283 struct stat statbuf; 284 for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) 285 { 286 Elf_Internal_Phdr *p = i_phdrp + phindex; 287 if (p->p_filesz) 288 { 289 bfd_size_type current = p->p_offset + p->p_filesz; 290 if (high < current) 291 high = current; 292 } 293 } 294 if (bfd_stat (abfd, &statbuf) == 0) 295 { 296 if ((bfd_size_type) statbuf.st_size < high) 297 { 298 (*_bfd_error_handler) 299 (_("Warning: %B is truncated: expected core file " 300 "size >= %lu, found: %lu."), 301 abfd, (unsigned long) high, (unsigned long) statbuf.st_size); 302 } 303 } 304 } 305 306 /* Save the entry point from the ELF header. */ 307 bfd_get_start_address (abfd) = i_ehdrp->e_entry; 308 return abfd->xvec; 309 310 wrong: 311 bfd_set_error (bfd_error_wrong_format); 312 fail: 313 return NULL; 314 } 315
