bfd/elfcore.h

   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 }