bfd/trad-core.c

   1 /* BFD back end for traditional Unix core files (U-area and raw sections)
   2    Copyright (C) 1988-2021 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 #include <dirent.h>
  29 #include <signal.h>
  30
  31 #include <sys/user.h>           /* After a.out.h  */
  32
  33 #ifdef TRAD_HEADER
  34 #include TRAD_HEADER
  35 #endif
  36
  37 #ifndef NBPG
  38 # define NBPG getpagesize()
  39 #endif
  40
  41 struct trad_core_struct
  42 {
  43   asection *data_section;
  44   asection *stack_section;
  45   asection *reg_section;
  46   struct user u;
  47 };
  48
  49 #define core_upage(bfd)  (&((bfd)->tdata.trad_core_data->u))
  50 #define core_datasec(bfd)  ((bfd)->tdata.trad_core_data->data_section)
  51 #define core_stacksec(bfd) ((bfd)->tdata.trad_core_data->stack_section)
  52 #define core_regsec(bfd)   ((bfd)->tdata.trad_core_data->reg_section)
  53
  54 /* forward declarations */
  55
  56 #define trad_unix_core_file_matches_executable_p generic_core_file_matches_executable_p
  57 #define trad_unix_core_file_pid _bfd_nocore_core_file_pid
  58
  59
  60 /* Handle 4.2-style (and perhaps also sysV-style) core dump file.  */
  61
  62 static bfd_cleanup
  63 trad_unix_core_file_p (bfd *abfd)
  64 {
  65   int val;
  66   struct user u;
  67   struct trad_core_struct *rawptr;
  68   size_t amt;
  69   flagword flags;
  70
  71 #ifdef TRAD_CORE_USER_OFFSET
  72   /* If defined, this macro is the file position of the user struct.  */
  73   if (bfd_seek (abfd, (file_ptr) TRAD_CORE_USER_OFFSET, SEEK_SET) != 0)
  74     return 0;
  75 #endif
  76
  77   val = bfd_bread ((void *) &u, (bfd_size_type) sizeof u, abfd);
  78   if (val != sizeof u)
  79     {
  80       /* Too small to be a core file */
  81       bfd_set_error (bfd_error_wrong_format);
  82       return 0;
  83     }
  84
  85   /* Sanity check perhaps??? */
  86   if (u.u_dsize > 0x1000000)    /* Remember, it's in pages...  */
  87     {
  88       bfd_set_error (bfd_error_wrong_format);
  89       return 0;
  90     }
  91   if (u.u_ssize > 0x1000000)
  92     {
  93       bfd_set_error (bfd_error_wrong_format);
  94       return 0;
  95     }
  96
  97   /* Check that the size claimed is no greater than the file size.  */
  98   {
  99     struct stat statbuf;
 100
 101     if (bfd_stat (abfd, &statbuf) < 0)
 102       return 0;
 103
 104     if ((ufile_ptr) NBPG * (UPAGES + u.u_dsize
 105 #ifdef TRAD_CORE_DSIZE_INCLUDES_TSIZE
 106                             - u.u_tsize
 107 #endif
 108                             + u.u_ssize)
 109         > (ufile_ptr) statbuf.st_size)
 110       {
 111         bfd_set_error (bfd_error_wrong_format);
 112         return 0;
 113       }
 114 #ifndef TRAD_CORE_ALLOW_ANY_EXTRA_SIZE
 115     if (((ufile_ptr) NBPG * (UPAGES + u.u_dsize + u.u_ssize)
 116 #ifdef TRAD_CORE_EXTRA_SIZE_ALLOWED
 117         /* Some systems write the file too big.  */
 118          + TRAD_CORE_EXTRA_SIZE_ALLOWED
 119 #endif
 120          )
 121         < (ufile_ptr) statbuf.st_size)
 122       {
 123         /* The file is too big.  Maybe it's not a core file
 124            or we otherwise have bad values for u_dsize and u_ssize).  */
 125         bfd_set_error (bfd_error_wrong_format);
 126         return 0;
 127       }
 128 #endif
 129   }
 130
 131   /* OK, we believe you.  You're a core file (sure, sure).  */
 132
 133   /* Allocate both the upage and the struct core_data at once, so
 134      a single free() will free them both.  */
 135   amt = sizeof (struct trad_core_struct);
 136   rawptr = (struct trad_core_struct *) bfd_zmalloc (amt);
 137   if (rawptr == NULL)
 138     return 0;
 139
 140   abfd->tdata.trad_core_data = rawptr;
 141
 142   rawptr->u = u; /*Copy the uarea into the tdata part of the bfd */
 143
 144   /* Create the sections.  */
 145
 146   flags = SEC_ALLOC + SEC_LOAD + SEC_HAS_CONTENTS;
 147   core_stacksec(abfd) = bfd_make_section_anyway_with_flags (abfd, ".stack",
 148                                                             flags);
 149   if (core_stacksec (abfd) == NULL)
 150     goto fail;
 151   core_datasec (abfd) = bfd_make_section_anyway_with_flags (abfd, ".data",
 152                                                             flags);
 153   if (core_datasec (abfd) == NULL)
 154     goto fail;
 155   core_regsec (abfd) = bfd_make_section_anyway_with_flags (abfd, ".reg",
 156                                                            SEC_HAS_CONTENTS);
 157   if (core_regsec (abfd) == NULL)
 158     goto fail;
 159
 160   core_datasec (abfd)->size =  NBPG * u.u_dsize
 161 #ifdef TRAD_CORE_DSIZE_INCLUDES_TSIZE
 162     - NBPG * u.u_tsize
 163 #endif
 164       ;
 165   core_stacksec (abfd)->size = NBPG * u.u_ssize;
 166   core_regsec (abfd)->size = NBPG * UPAGES; /* Larger than sizeof struct u */
 167
 168   /* What a hack... we'd like to steal it from the exec file,
 169      since the upage does not seem to provide it.  FIXME.  */
 170 #ifdef HOST_DATA_START_ADDR
 171   core_datasec (abfd)->vma = HOST_DATA_START_ADDR;
 172 #else
 173   core_datasec (abfd)->vma = HOST_TEXT_START_ADDR + (NBPG * u.u_tsize);
 174 #endif
 175
 176 #ifdef HOST_STACK_START_ADDR
 177   core_stacksec (abfd)->vma = HOST_STACK_START_ADDR;
 178 #else
 179   core_stacksec (abfd)->vma = HOST_STACK_END_ADDR - (NBPG * u.u_ssize);
 180 #endif
 181
 182   /* This is tricky.  As the "register section", we give them the entire
 183      upage and stack.  u.u_ar0 points to where "register 0" is stored.
 184      There are two tricks with this, though.  One is that the rest of the
 185      registers might be at positive or negative (or both) displacements
 186      from *u_ar0.  The other is that u_ar0 is sometimes an absolute address
 187      in kernel memory, and on other systems it is an offset from the beginning
 188      of the `struct user'.
 189
 190      As a practical matter, we don't know where the registers actually are,
 191      so we have to pass the whole area to GDB.  We encode the value of u_ar0
 192      by setting the .regs section up so that its virtual memory address
 193      0 is at the place pointed to by u_ar0 (by setting the vma of the start
 194      of the section to -u_ar0).  GDB uses this info to locate the regs,
 195      using minor trickery to get around the offset-or-absolute-addr problem.  */
 196   core_regsec (abfd)->vma = - (bfd_vma) (unsigned long) u.u_ar0;
 197
 198   core_datasec (abfd)->filepos = NBPG * UPAGES;
 199   core_stacksec (abfd)->filepos = (NBPG * UPAGES) + NBPG * u.u_dsize
 200 #ifdef TRAD_CORE_DSIZE_INCLUDES_TSIZE
 201     - NBPG * u.u_tsize
 202 #endif
 203       ;
 204   core_regsec (abfd)->filepos = 0; /* Register segment is the upage */
 205
 206   /* Align to word at least */
 207   core_stacksec (abfd)->alignment_power = 2;
 208   core_datasec (abfd)->alignment_power = 2;
 209   core_regsec (abfd)->alignment_power = 2;
 210
 211   return _bfd_no_cleanup;
 212
 213  fail:
 214   bfd_release (abfd, abfd->tdata.any);
 215   abfd->tdata.any = NULL;
 216   bfd_section_list_clear (abfd);
 217   return NULL;
 218 }
 219
 220 static char *
 221 trad_unix_core_file_failing_command (bfd *abfd)
 222 {
 223 #ifndef NO_CORE_COMMAND
 224   char *com = abfd->tdata.trad_core_data->u.u_comm;
 225   if (*com)
 226     return com;
 227   else
 228 #endif
 229     return 0;
 230 }
 231
 232 static int
 233 trad_unix_core_file_failing_signal (bfd *ignore_abfd ATTRIBUTE_UNUSED)
 234 {
 235 #ifdef TRAD_UNIX_CORE_FILE_FAILING_SIGNAL
 236   return TRAD_UNIX_CORE_FILE_FAILING_SIGNAL(ignore_abfd);
 237 #else
 238   return -1;            /* FIXME, where is it? */
 239 #endif
 240 }
 241 \f
 242 /* If somebody calls any byte-swapping routines, shoot them.  */
 243 static void
 244 swap_abort (void)
 245 {
 246   abort (); /* This way doesn't require any declaration for ANSI to fuck up */
 247 }
 248
 249 #define NO_GET ((bfd_vma (*) (const void *)) swap_abort)
 250 #define NO_PUT ((void (*) (bfd_vma, void *)) swap_abort)
 251 #define NO_GETS ((bfd_signed_vma (*) (const void *)) swap_abort)
 252 #define NO_GET64 ((bfd_uint64_t (*) (const void *)) swap_abort)
 253 #define NO_PUT64 ((void (*) (bfd_uint64_t, void *)) swap_abort)
 254 #define NO_GETS64 ((bfd_int64_t (*) (const void *)) swap_abort)
 255
 256 const bfd_target core_trad_vec =
 257   {
 258     "trad-core",
 259     bfd_target_unknown_flavour,
 260     BFD_ENDIAN_UNKNOWN,         /* target byte order */
 261     BFD_ENDIAN_UNKNOWN,         /* target headers byte order */
 262     (HAS_RELOC | EXEC_P |       /* object flags */
 263      HAS_LINENO | HAS_DEBUG |
 264      HAS_SYMS | HAS_LOCALS | WP_TEXT | D_PAGED),
 265     (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC), /* section flags */
 266     0,                          /* symbol prefix */
 267     ' ',                        /* ar_pad_char */
 268     16,                         /* ar_max_namelen */
 269     0,                          /* match priority.  */
 270     TARGET_KEEP_UNUSED_SECTION_SYMBOLS, /* keep unused section symbols.  */
 271     NO_GET64, NO_GETS64, NO_PUT64,      /* 64 bit data */
 272     NO_GET, NO_GETS, NO_PUT,            /* 32 bit data */
 273     NO_GET, NO_GETS, NO_PUT,            /* 16 bit data */
 274     NO_GET64, NO_GETS64, NO_PUT64,      /* 64 bit hdrs */
 275     NO_GET, NO_GETS, NO_PUT,            /* 32 bit hdrs */
 276     NO_GET, NO_GETS, NO_PUT,            /* 16 bit hdrs */
 277
 278     {                           /* bfd_check_format */
 279       _bfd_dummy_target,                /* unknown format */
 280       _bfd_dummy_target,                /* object file */
 281       _bfd_dummy_target,                /* archive */
 282       trad_unix_core_file_p             /* a core file */
 283     },
 284     {                           /* bfd_set_format */
 285       _bfd_bool_bfd_false_error,
 286       _bfd_bool_bfd_false_error,
 287       _bfd_bool_bfd_false_error,
 288       _bfd_bool_bfd_false_error
 289     },
 290     {                           /* bfd_write_contents */
 291       _bfd_bool_bfd_false_error,
 292       _bfd_bool_bfd_false_error,
 293       _bfd_bool_bfd_false_error,
 294       _bfd_bool_bfd_false_error
 295     },
 296
 297     BFD_JUMP_TABLE_GENERIC (_bfd_generic),
 298     BFD_JUMP_TABLE_COPY (_bfd_generic),
 299     BFD_JUMP_TABLE_CORE (trad_unix),
 300     BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 301     BFD_JUMP_TABLE_SYMBOLS (_bfd_nosymbols),
 302     BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
 303     BFD_JUMP_TABLE_WRITE (_bfd_generic),
 304     BFD_JUMP_TABLE_LINK (_bfd_nolink),
 305     BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 306
 307     NULL,
 308
 309     NULL                        /* backend_data */
 310   };