1 /* ELF core file support for BFD. 2 Copyright 1995, 1996, 1997, 1998, 2000, 2001, 2002, 2003, 2005, 2007, 3 2008 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 bfd_boolean 35 elf_core_file_matches_executable_p (bfd *core_bfd, bfd *exec_bfd) 36 { 37 char* corename; 38 39 /* xvecs must match if both are ELF files for the same target. */ 40 41 if (core_bfd->xvec != exec_bfd->xvec) 42 { 43 bfd_set_error (bfd_error_system_call); 44 return FALSE; 45 } 46 47 /* See if the name in the corefile matches the executable name. */ 48 corename = elf_tdata (core_bfd)->core_program; 49 if (corename != NULL) 50 { 51 const char* execname = strrchr (exec_bfd->filename, '/'); 52 53 execname = execname ? execname + 1 : exec_bfd->filename; 54 55 if (strcmp (execname, corename) != 0) 56 return FALSE; 57 } 58 59 return TRUE; 60 } 61 62 /* Core files are simply standard ELF formatted files that partition 63 the file using the execution view of the file (program header table) 64 rather than the linking view. In fact, there is no section header 65 table in a core file. 66 67 The process status information (including the contents of the general 68 register set) and the floating point register set are stored in a 69 segment of type PT_NOTE. We handcraft a couple of extra bfd sections 70 that allow standard bfd access to the general registers (.reg) and the 71 floating point registers (.reg2). */ 72 73 const bfd_target * 74 elf_core_file_p (bfd *abfd) 75 { 76 Elf_External_Ehdr x_ehdr; /* Elf file header, external form. */ 77 Elf_Internal_Ehdr *i_ehdrp; /* Elf file header, internal form. */ 78 Elf_Internal_Phdr *i_phdrp; /* Elf program header, internal form. */ 79 unsigned int phindex; 80 const struct elf_backend_data *ebd; 81 struct bfd_preserve preserve; 82 bfd_size_type amt; 83 84 preserve.marker = NULL; 85 86 /* Read in the ELF header in external format. */ 87 if (bfd_bread (&x_ehdr, sizeof (x_ehdr), abfd) != sizeof (x_ehdr)) 88 { 89 if (bfd_get_error () != bfd_error_system_call) 90 goto wrong; 91 else 92 goto fail; 93 } 94 95 /* Check the magic number. */ 96 if (! elf_file_p (&x_ehdr)) 97 goto wrong; 98 99 /* FIXME: Check EI_VERSION here ! */ 100 101 /* Check the address size ("class"). */ 102 if (x_ehdr.e_ident[EI_CLASS] != ELFCLASS) 103 goto wrong; 104 105 /* Check the byteorder. */ 106 switch (x_ehdr.e_ident[EI_DATA]) 107 { 108 case ELFDATA2MSB: /* Big-endian. */ 109 if (! bfd_big_endian (abfd)) 110 goto wrong; 111 break; 112 case ELFDATA2LSB: /* Little-endian. */ 113 if (! bfd_little_endian (abfd)) 114 goto wrong; 115 break; 116 default: 117 goto wrong; 118 } 119 120 if (!bfd_preserve_save (abfd, &preserve)) 121 goto fail; 122 123 /* Give abfd an elf_obj_tdata. */ 124 if (! (*abfd->xvec->_bfd_set_format[bfd_core]) (abfd)) 125 goto fail; 126 preserve.marker = elf_tdata (abfd); 127 128 /* Swap in the rest of the header, now that we have the byte order. */ 129 i_ehdrp = elf_elfheader (abfd); 130 elf_swap_ehdr_in (abfd, &x_ehdr, i_ehdrp); 131 132 #if DEBUG & 1 133 elf_debug_file (i_ehdrp); 134 #endif 135 136 ebd = get_elf_backend_data (abfd); 137 138 /* Check that the ELF e_machine field matches what this particular 139 BFD format expects. */ 140 141 if (ebd->elf_machine_code != i_ehdrp->e_machine 142 && (ebd->elf_machine_alt1 == 0 143 || i_ehdrp->e_machine != ebd->elf_machine_alt1) 144 && (ebd->elf_machine_alt2 == 0 145 || i_ehdrp->e_machine != ebd->elf_machine_alt2)) 146 { 147 const bfd_target * const *target_ptr; 148 149 if (ebd->elf_machine_code != EM_NONE) 150 goto wrong; 151 152 /* This is the generic ELF target. Let it match any ELF target 153 for which we do not have a specific backend. */ 154 155 for (target_ptr = bfd_target_vector; *target_ptr != NULL; target_ptr++) 156 { 157 const struct elf_backend_data *back; 158 159 if ((*target_ptr)->flavour != bfd_target_elf_flavour) 160 continue; 161 back = xvec_get_elf_backend_data (*target_ptr); 162 if (back->s->arch_size != ARCH_SIZE) 163 continue; 164 if (back->elf_machine_code == i_ehdrp->e_machine 165 || (back->elf_machine_alt1 != 0 166 && i_ehdrp->e_machine == back->elf_machine_alt1) 167 || (back->elf_machine_alt2 != 0 168 && i_ehdrp->e_machine == back->elf_machine_alt2)) 169 { 170 /* target_ptr is an ELF backend which matches this 171 object file, so reject the generic ELF target. */ 172 goto wrong; 173 } 174 } 175 } 176 177 /* If there is no program header, or the type is not a core file, then 178 we are hosed. */ 179 if (i_ehdrp->e_phoff == 0 || i_ehdrp->e_type != ET_CORE) 180 goto wrong; 181 182 /* Does BFD's idea of the phdr size match the size 183 recorded in the file? */ 184 if (i_ehdrp->e_phentsize != sizeof (Elf_External_Phdr)) 185 goto wrong; 186 187 /* Move to the start of the program headers. */ 188 if (bfd_seek (abfd, (file_ptr) i_ehdrp->e_phoff, SEEK_SET) != 0) 189 goto wrong; 190 191 /* Allocate space for the program headers. */ 192 amt = sizeof (*i_phdrp) * i_ehdrp->e_phnum; 193 i_phdrp = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt); 194 if (!i_phdrp) 195 goto fail; 196 197 elf_tdata (abfd)->phdr = i_phdrp; 198 199 /* Read and convert to internal form. */ 200 for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) 201 { 202 Elf_External_Phdr x_phdr; 203 204 if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr)) 205 goto fail; 206 207 elf_swap_phdr_in (abfd, &x_phdr, i_phdrp + phindex); 208 } 209 210 /* Set the machine architecture. Do this before processing the 211 program headers since we need to know the architecture type 212 when processing the notes of some systems' core files. */ 213 if (! bfd_default_set_arch_mach (abfd, ebd->arch, 0) 214 /* It's OK if this fails for the generic target. */ 215 && ebd->elf_machine_code != EM_NONE) 216 goto fail; 217 218 /* Let the backend double check the format and override global 219 information. We do this before processing the program headers 220 to allow the correct machine (as opposed to just the default 221 machine) to be set, making it possible for grok_prstatus and 222 grok_psinfo to rely on the mach setting. */ 223 if (ebd->elf_backend_object_p != NULL 224 && ! ebd->elf_backend_object_p (abfd)) 225 goto wrong; 226 227 /* Process each program header. */ 228 for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) 229 if (! bfd_section_from_phdr (abfd, i_phdrp + phindex, (int) phindex)) 230 goto fail; 231 232 /* Check for core truncation. */ 233 { 234 bfd_size_type high = 0; 235 struct stat statbuf; 236 for (phindex = 0; phindex < i_ehdrp->e_phnum; ++phindex) 237 { 238 Elf_Internal_Phdr *p = i_phdrp + phindex; 239 if (p->p_filesz) 240 { 241 bfd_size_type current = p->p_offset + p->p_filesz; 242 if (high < current) 243 high = current; 244 } 245 } 246 if (bfd_stat (abfd, &statbuf) == 0) 247 { 248 if ((bfd_size_type) statbuf.st_size < high) 249 { 250 (*_bfd_error_handler) 251 (_("Warning: %B is truncated: expected core file " 252 "size >= %lu, found: %lu."), 253 abfd, (unsigned long) high, (unsigned long) statbuf.st_size); 254 } 255 } 256 } 257 258 /* Save the entry point from the ELF header. */ 259 bfd_get_start_address (abfd) = i_ehdrp->e_entry; 260 261 bfd_preserve_finish (abfd, &preserve); 262 return abfd->xvec; 263 264 wrong: 265 /* There is way too much undoing of half-known state here. The caller, 266 bfd_check_format_matches, really shouldn't iterate on live bfd's to 267 check match/no-match like it does. We have to rely on that a call to 268 bfd_default_set_arch_mach with the previously known mach, undoes what 269 was done by the first bfd_default_set_arch_mach (with mach 0) here. 270 For this to work, only elf-data and the mach may be changed by the 271 target-specific elf_backend_object_p function. Note that saving the 272 whole bfd here and restoring it would be even worse; the first thing 273 you notice is that the cached bfd file position gets out of sync. */ 274 bfd_set_error (bfd_error_wrong_format); 275 276 fail: 277 if (preserve.marker != NULL) 278 bfd_preserve_restore (abfd, &preserve); 279 return NULL; 280 } 281