bfd/trad-core.c

   1 /* BFD back end for traditional Unix core files (U-area and raw sections)
   2    Copyright (C) 1988-2020 Free Software Foundation, Inc.
   3    Written by John Gilmore of Cygnus Support.
   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 #include "sysdep.h"
  23 #include "bfd.h"
  24 #include "libbfd.h"
  25 #include "libaout.h"           /* BFD a.out internal data structures */
  26
  27 #include <sys/param.h>
  28 #ifdef HAVE_DIRENT_H
  29 # include <dirent.h>
  30 #else
  31 # ifdef HAVE_SYS_NDIR_H
  32 #  include <sys/ndir.h>
  33 # endif
  34 # ifdef HAVE_SYS_DIR_H
  35 #  include <sys/dir.h>
  36 # endif
  37 # ifdef HAVE_NDIR_H
  38 #  include <ndir.h>
  39 # endif
  40 #endif
  41 #include <signal.h>
  42
  43 #include <sys/user.h>           /* After a.out.h  */
  44
  45 #ifdef TRAD_HEADER
  46 #include TRAD_HEADER
  47 #endif
  48
  49 #ifndef NBPG
  50 # define NBPG getpagesize()
  51 #endif
  52
  53 struct trad_core_struct
  54 {
  55   asection *data_section;
  56   asection *stack_section;
  57   asection *reg_section;
  58   struct user u;
  59 };
  60
  61 #define core_upage(bfd)  (&((bfd)->tdata.trad_core_data->u))
  62 #define core_datasec(bfd)  ((bfd)->tdata.trad_core_data->data_section)
  63 #define core_stacksec(bfd) ((bfd)->tdata.trad_core_data->stack_section)
  64 #define core_regsec(bfd)   ((bfd)->tdata.trad_core_data->reg_section)
  65
  66 /* forward declarations */
  67
  68 #define trad_unix_core_file_matches_executable_p generic_core_file_matches_executable_p
  69 #define trad_unix_core_file_pid _bfd_nocore_core_file_pid
  70
  71
  72 /* Handle 4.2-style (and perhaps also sysV-style) core dump file.  */
  73
  74 static bfd_cleanup
  75 trad_unix_core_file_p (bfd *abfd)
  76 {
  77   int val;
  78   struct user u;
  79   struct trad_core_struct *rawptr;
  80   size_t amt;
  81   flagword flags;
  82
  83 #ifdef TRAD_CORE_USER_OFFSET
  84   /* If defined, this macro is the file position of the user struct.  */
  85   if (bfd_seek (abfd, (file_ptr) TRAD_CORE_USER_OFFSET, SEEK_SET) != 0)
  86     return 0;
  87 #endif
  88
  89   val = bfd_bread ((void *) &u, (bfd_size_type) sizeof u, abfd);
  90   if (val != sizeof u)
  91     {
  92       /* Too small to be a core file */
  93       bfd_set_error (bfd_error_wrong_format);
  94       return 0;
  95     }
  96
  97   /* Sanity check perhaps??? */
  98   if (u.u_dsize > 0x1000000)    /* Remember, it's in pages...  */
  99     {
 100       bfd_set_error (bfd_error_wrong_format);
 101       return 0;
 102     }
 103   if (u.u_ssize > 0x1000000)
 104     {
 105       bfd_set_error (bfd_error_wrong_format);
 106       return 0;
 107     }
 108
 109   /* Check that the size claimed is no greater than the file size.  */
 110   {
 111     struct stat statbuf;
 112
 113     if (bfd_stat (abfd, &statbuf) < 0)
 114       return 0;
 115
 116     if ((ufile_ptr) NBPG * (UPAGES + u.u_dsize
 117 #ifdef TRAD_CORE_DSIZE_INCLUDES_TSIZE
 118                             - u.u_tsize
 119 #endif
 120                             + u.u_ssize)
 121         > (ufile_ptr) statbuf.st_size)
 122       {
 123         bfd_set_error (bfd_error_wrong_format);
 124         return 0;
 125       }
 126 #ifndef TRAD_CORE_ALLOW_ANY_EXTRA_SIZE
 127     if (((ufile_ptr) NBPG * (UPAGES + u.u_dsize + u.u_ssize)
 128 #ifdef TRAD_CORE_EXTRA_SIZE_ALLOWED
 129         /* Some systems write the file too big.  */
 130          + TRAD_CORE_EXTRA_SIZE_ALLOWED
 131 #endif
 132          )
 133         < (ufile_ptr) statbuf.st_size)
 134       {
 135         /* The file is too big.  Maybe it's not a core file
 136            or we otherwise have bad values for u_dsize and u_ssize).  */
 137         bfd_set_error (bfd_error_wrong_format);
 138         return 0;
 139       }
 140 #endif
 141   }
 142
 143   /* OK, we believe you.  You're a core file (sure, sure).  */
 144
 145   /* Allocate both the upage and the struct core_data at once, so
 146      a single free() will free them both.  */
 147   amt = sizeof (struct trad_core_struct);
 148   rawptr = (struct trad_core_struct *) bfd_zmalloc (amt);
 149   if (rawptr == NULL)
 150     return 0;
 151
 152   abfd->tdata.trad_core_data = rawptr;
 153
 154   rawptr->u = u; /*Copy the uarea into the tdata part of the bfd */
 155
 156   /* Create the sections.  */
 157
 158   flags = SEC_ALLOC + SEC_LOAD + SEC_HAS_CONTENTS;
 159   core_stacksec(abfd) = bfd_make_section_anyway_with_flags (abfd, ".stack",
 160                                                             flags);
 161   if (core_stacksec (abfd) == NULL)
 162     goto fail;
 163   core_datasec (abfd) = bfd_make_section_anyway_with_flags (abfd, ".data",
 164                                                             flags);
 165   if (core_datasec (abfd) == NULL)
 166     goto fail;
 167   core_regsec (abfd) = bfd_make_section_anyway_with_flags (abfd, ".reg",
 168                                                            SEC_HAS_CONTENTS);
 169   if (core_regsec (abfd) == NULL)
 170     goto fail;
 171
 172   core_datasec (abfd)->size =  NBPG * u.u_dsize
 173 #ifdef TRAD_CORE_DSIZE_INCLUDES_TSIZE
 174     - NBPG * u.u_tsize
 175 #endif
 176       ;
 177   core_stacksec (abfd)->size = NBPG * u.u_ssize;
 178   core_regsec (abfd)->size = NBPG * UPAGES; /* Larger than sizeof struct u */
 179
 180   /* What a hack... we'd like to steal it from the exec file,
 181      since the upage does not seem to provide it.  FIXME.  */
 182 #ifdef HOST_DATA_START_ADDR
 183   core_datasec (abfd)->vma = HOST_DATA_START_ADDR;
 184 #else
 185   core_datasec (abfd)->vma = HOST_TEXT_START_ADDR + (NBPG * u.u_tsize);
 186 #endif
 187
 188 #ifdef HOST_STACK_START_ADDR
 189   core_stacksec (abfd)->vma = HOST_STACK_START_ADDR;
 190 #else
 191   core_stacksec (abfd)->vma = HOST_STACK_END_ADDR - (NBPG * u.u_ssize);
 192 #endif
 193
 194   /* This is tricky.  As the "register section", we give them the entire
 195      upage and stack.  u.u_ar0 points to where "register 0" is stored.
 196      There are two tricks with this, though.  One is that the rest of the
 197      registers might be at positive or negative (or both) displacements
 198      from *u_ar0.  The other is that u_ar0 is sometimes an absolute address
 199      in kernel memory, and on other systems it is an offset from the beginning
 200      of the `struct user'.
 201
 202      As a practical matter, we don't know where the registers actually are,
 203      so we have to pass the whole area to GDB.  We encode the value of u_ar0
 204      by setting the .regs section up so that its virtual memory address
 205      0 is at the place pointed to by u_ar0 (by setting the vma of the start
 206      of the section to -u_ar0).  GDB uses this info to locate the regs,
 207      using minor trickery to get around the offset-or-absolute-addr problem.  */
 208   core_regsec (abfd)->vma = - (bfd_vma) (unsigned long) u.u_ar0;
 209
 210   core_datasec (abfd)->filepos = NBPG * UPAGES;
 211   core_stacksec (abfd)->filepos = (NBPG * UPAGES) + NBPG * u.u_dsize
 212 #ifdef TRAD_CORE_DSIZE_INCLUDES_TSIZE
 213     - NBPG * u.u_tsize
 214 #endif
 215       ;
 216   core_regsec (abfd)->filepos = 0; /* Register segment is the upage */
 217
 218   /* Align to word at least */
 219   core_stacksec (abfd)->alignment_power = 2;
 220   core_datasec (abfd)->alignment_power = 2;
 221   core_regsec (abfd)->alignment_power = 2;
 222
 223   return _bfd_no_cleanup;
 224
 225  fail:
 226   bfd_release (abfd, abfd->tdata.any);
 227   abfd->tdata.any = NULL;
 228   bfd_section_list_clear (abfd);
 229   return NULL;
 230 }
 231
 232 static char *
 233 trad_unix_core_file_failing_command (bfd *abfd)
 234 {
 235 #ifndef NO_CORE_COMMAND
 236   char *com = abfd->tdata.trad_core_data->u.u_comm;
 237   if (*com)
 238     return com;
 239   else
 240 #endif
 241     return 0;
 242 }
 243
 244 static int
 245 trad_unix_core_file_failing_signal (bfd *ignore_abfd ATTRIBUTE_UNUSED)
 246 {
 247 #ifdef TRAD_UNIX_CORE_FILE_FAILING_SIGNAL
 248   return TRAD_UNIX_CORE_FILE_FAILING_SIGNAL(ignore_abfd);
 249 #else
 250   return -1;            /* FIXME, where is it? */
 251 #endif
 252 }
 253 \f
 254 /* If somebody calls any byte-swapping routines, shoot them.  */
 255 static void
 256 swap_abort (void)
 257 {
 258   abort (); /* This way doesn't require any declaration for ANSI to fuck up */
 259 }
 260
 261 #define NO_GET ((bfd_vma (*) (const void *)) swap_abort)
 262 #define NO_PUT ((void (*) (bfd_vma, void *)) swap_abort)
 263 #define NO_GETS ((bfd_signed_vma (*) (const void *)) swap_abort)
 264 #define NO_GET64 ((bfd_uint64_t (*) (const void *)) swap_abort)
 265 #define NO_PUT64 ((void (*) (bfd_uint64_t, void *)) swap_abort)
 266 #define NO_GETS64 ((bfd_int64_t (*) (const void *)) swap_abort)
 267
 268 const bfd_target core_trad_vec =
 269   {
 270     "trad-core",
 271     bfd_target_unknown_flavour,
 272     BFD_ENDIAN_UNKNOWN,         /* target byte order */
 273     BFD_ENDIAN_UNKNOWN,         /* target headers byte order */
 274     (HAS_RELOC | EXEC_P |       /* object flags */
 275      HAS_LINENO | HAS_DEBUG |
 276      HAS_SYMS | HAS_LOCALS | WP_TEXT | D_PAGED),
 277     (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC), /* section flags */
 278     0,                          /* symbol prefix */
 279     ' ',                        /* ar_pad_char */
 280     16,                         /* ar_max_namelen */
 281     0,                          /* match priority.  */
 282     NO_GET64, NO_GETS64, NO_PUT64,      /* 64 bit data */
 283     NO_GET, NO_GETS, NO_PUT,            /* 32 bit data */
 284     NO_GET, NO_GETS, NO_PUT,            /* 16 bit data */
 285     NO_GET64, NO_GETS64, NO_PUT64,      /* 64 bit hdrs */
 286     NO_GET, NO_GETS, NO_PUT,            /* 32 bit hdrs */
 287     NO_GET, NO_GETS, NO_PUT,            /* 16 bit hdrs */
 288
 289     {                           /* bfd_check_format */
 290       _bfd_dummy_target,                /* unknown format */
 291       _bfd_dummy_target,                /* object file */
 292       _bfd_dummy_target,                /* archive */
 293       trad_unix_core_file_p             /* a core file */
 294     },
 295     {                           /* bfd_set_format */
 296       _bfd_bool_bfd_false_error,
 297       _bfd_bool_bfd_false_error,
 298       _bfd_bool_bfd_false_error,
 299       _bfd_bool_bfd_false_error
 300     },
 301     {                           /* bfd_write_contents */
 302       _bfd_bool_bfd_false_error,
 303       _bfd_bool_bfd_false_error,
 304       _bfd_bool_bfd_false_error,
 305       _bfd_bool_bfd_false_error
 306     },
 307
 308     BFD_JUMP_TABLE_GENERIC (_bfd_generic),
 309     BFD_JUMP_TABLE_COPY (_bfd_generic),
 310     BFD_JUMP_TABLE_CORE (trad_unix),
 311     BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 312     BFD_JUMP_TABLE_SYMBOLS (_bfd_nosymbols),
 313     BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
 314     BFD_JUMP_TABLE_WRITE (_bfd_generic),
 315     BFD_JUMP_TABLE_LINK (_bfd_nolink),
 316     BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 317
 318     NULL,
 319
 320     NULL                        /* backend_data */
 321   };