bfd/trad-core.c

   1 /* BFD back end for traditional Unix core files (U-area and raw sections)
   2    Copyright (C) 1988-2024 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   flagword flags;
  69
  70 #ifdef TRAD_CORE_USER_OFFSET
  71   /* If defined, this macro is the file position of the user struct.  */
  72   if (bfd_seek (abfd, TRAD_CORE_USER_OFFSET, SEEK_SET) != 0)
  73     return 0;
  74 #endif
  75
  76   val = bfd_read (&u, sizeof u, abfd);
  77   if (val != sizeof u)
  78     {
  79       /* Too small to be a core file */
  80       bfd_set_error (bfd_error_wrong_format);
  81       return 0;
  82     }
  83
  84   /* Sanity check perhaps??? */
  85   if (u.u_dsize > 0x1000000)    /* Remember, it's in pages...  */
  86     {
  87       bfd_set_error (bfd_error_wrong_format);
  88       return 0;
  89     }
  90   if (u.u_ssize > 0x1000000)
  91     {
  92       bfd_set_error (bfd_error_wrong_format);
  93       return 0;
  94     }
  95
  96   /* Check that the size claimed is no greater than the file size.  */
  97   {
  98     struct stat statbuf;
  99
 100     if (bfd_stat (abfd, &statbuf) < 0)
 101       return 0;
 102
 103     if ((ufile_ptr) NBPG * (UPAGES + u.u_dsize
 104 #ifdef TRAD_CORE_DSIZE_INCLUDES_TSIZE
 105                             - u.u_tsize
 106 #endif
 107                             + u.u_ssize)
 108         > (ufile_ptr) statbuf.st_size)
 109       {
 110         bfd_set_error (bfd_error_wrong_format);
 111         return 0;
 112       }
 113 #ifndef TRAD_CORE_ALLOW_ANY_EXTRA_SIZE
 114     if (((ufile_ptr) NBPG * (UPAGES + u.u_dsize + u.u_ssize)
 115 #ifdef TRAD_CORE_EXTRA_SIZE_ALLOWED
 116         /* Some systems write the file too big.  */
 117          + TRAD_CORE_EXTRA_SIZE_ALLOWED
 118 #endif
 119          )
 120         < (ufile_ptr) statbuf.st_size)
 121       {
 122         /* The file is too big.  Maybe it's not a core file
 123            or we otherwise have bad values for u_dsize and u_ssize).  */
 124         bfd_set_error (bfd_error_wrong_format);
 125         return 0;
 126       }
 127 #endif
 128   }
 129
 130   /* OK, we believe you.  You're a core file (sure, sure).  */
 131
 132   /* Allocate both the upage and the struct core_data at once, so
 133      a single free() will free them both.  */
 134   rawptr = bfd_alloc (abfd, sizeof (*rawptr) + 1);
 135   if (rawptr == NULL)
 136     return 0;
 137
 138   abfd->tdata.trad_core_data = rawptr;
 139
 140   rawptr->u = u; /*Copy the uarea into the tdata part of the bfd */
 141
 142   /* Ensure core_file_failing_command string is terminated.  This is
 143      just to stop buffer overflows on fuzzed files.  */
 144   ((char *) rawptr)[sizeof (*rawptr)] = 0;
 145
 146   /* Create the sections.  */
 147
 148   flags = SEC_ALLOC + SEC_LOAD + SEC_HAS_CONTENTS;
 149   core_stacksec(abfd) = bfd_make_section_anyway_with_flags (abfd, ".stack",
 150                                                             flags);
 151   if (core_stacksec (abfd) == NULL)
 152     goto fail;
 153   core_datasec (abfd) = bfd_make_section_anyway_with_flags (abfd, ".data",
 154                                                             flags);
 155   if (core_datasec (abfd) == NULL)
 156     goto fail;
 157   core_regsec (abfd) = bfd_make_section_anyway_with_flags (abfd, ".reg",
 158                                                            SEC_HAS_CONTENTS);
 159   if (core_regsec (abfd) == NULL)
 160     goto fail;
 161
 162   core_datasec (abfd)->size =  NBPG * u.u_dsize
 163 #ifdef TRAD_CORE_DSIZE_INCLUDES_TSIZE
 164     - NBPG * u.u_tsize
 165 #endif
 166       ;
 167   core_stacksec (abfd)->size = NBPG * u.u_ssize;
 168   core_regsec (abfd)->size = NBPG * UPAGES; /* Larger than sizeof struct u */
 169
 170   /* What a hack... we'd like to steal it from the exec file,
 171      since the upage does not seem to provide it.  FIXME.  */
 172 #ifdef HOST_DATA_START_ADDR
 173   core_datasec (abfd)->vma = HOST_DATA_START_ADDR;
 174 #else
 175   core_datasec (abfd)->vma = HOST_TEXT_START_ADDR + (NBPG * u.u_tsize);
 176 #endif
 177
 178 #ifdef HOST_STACK_START_ADDR
 179   core_stacksec (abfd)->vma = HOST_STACK_START_ADDR;
 180 #else
 181   core_stacksec (abfd)->vma = HOST_STACK_END_ADDR - (NBPG * u.u_ssize);
 182 #endif
 183
 184   /* This is tricky.  As the "register section", we give them the entire
 185      upage and stack.  u.u_ar0 points to where "register 0" is stored.
 186      There are two tricks with this, though.  One is that the rest of the
 187      registers might be at positive or negative (or both) displacements
 188      from *u_ar0.  The other is that u_ar0 is sometimes an absolute address
 189      in kernel memory, and on other systems it is an offset from the beginning
 190      of the `struct user'.
 191
 192      As a practical matter, we don't know where the registers actually are,
 193      so we have to pass the whole area to GDB.  We encode the value of u_ar0
 194      by setting the .regs section up so that its virtual memory address
 195      0 is at the place pointed to by u_ar0 (by setting the vma of the start
 196      of the section to -u_ar0).  GDB uses this info to locate the regs,
 197      using minor trickery to get around the offset-or-absolute-addr problem.  */
 198   core_regsec (abfd)->vma = - (bfd_vma) (unsigned long) u.u_ar0;
 199
 200   core_datasec (abfd)->filepos = NBPG * UPAGES;
 201   core_stacksec (abfd)->filepos = (NBPG * UPAGES) + NBPG * u.u_dsize
 202 #ifdef TRAD_CORE_DSIZE_INCLUDES_TSIZE
 203     - NBPG * u.u_tsize
 204 #endif
 205       ;
 206   core_regsec (abfd)->filepos = 0; /* Register segment is the upage */
 207
 208   /* Align to word at least */
 209   core_stacksec (abfd)->alignment_power = 2;
 210   core_datasec (abfd)->alignment_power = 2;
 211   core_regsec (abfd)->alignment_power = 2;
 212
 213   return _bfd_no_cleanup;
 214
 215  fail:
 216   bfd_release (abfd, abfd->tdata.any);
 217   abfd->tdata.any = NULL;
 218   bfd_section_list_clear (abfd);
 219   return NULL;
 220 }
 221
 222 static char *
 223 trad_unix_core_file_failing_command (bfd *abfd)
 224 {
 225 #ifndef NO_CORE_COMMAND
 226   char *com = abfd->tdata.trad_core_data->u.u_comm;
 227   if (*com)
 228     return com;
 229   else
 230 #endif
 231     return 0;
 232 }
 233
 234 static int
 235 trad_unix_core_file_failing_signal (bfd *ignore_abfd ATTRIBUTE_UNUSED)
 236 {
 237 #ifdef TRAD_UNIX_CORE_FILE_FAILING_SIGNAL
 238   return TRAD_UNIX_CORE_FILE_FAILING_SIGNAL(ignore_abfd);
 239 #else
 240   return -1;            /* FIXME, where is it? */
 241 #endif
 242 }
 243 \f
 244 /* If somebody calls any byte-swapping routines, shoot them.  */
 245 static void
 246 swap_abort (void)
 247 {
 248   abort (); /* This way doesn't require any declaration for ANSI to fuck up */
 249 }
 250
 251 #define NO_GET ((bfd_vma (*) (const void *)) swap_abort)
 252 #define NO_PUT ((void (*) (bfd_vma, void *)) swap_abort)
 253 #define NO_GETS ((bfd_signed_vma (*) (const void *)) swap_abort)
 254 #define NO_GET64 ((uint64_t (*) (const void *)) swap_abort)
 255 #define NO_PUT64 ((void (*) (uint64_t, void *)) swap_abort)
 256 #define NO_GETS64 ((int64_t (*) (const void *)) swap_abort)
 257
 258 const bfd_target core_trad_vec =
 259   {
 260     "trad-core",
 261     bfd_target_unknown_flavour,
 262     BFD_ENDIAN_UNKNOWN,         /* target byte order */
 263     BFD_ENDIAN_UNKNOWN,         /* target headers byte order */
 264     (HAS_RELOC | EXEC_P |       /* object flags */
 265      HAS_LINENO | HAS_DEBUG |
 266      HAS_SYMS | HAS_LOCALS | WP_TEXT | D_PAGED),
 267     (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC), /* section flags */
 268     0,                          /* symbol prefix */
 269     ' ',                        /* ar_pad_char */
 270     16,                         /* ar_max_namelen */
 271     0,                          /* match priority.  */
 272     TARGET_KEEP_UNUSED_SECTION_SYMBOLS, /* keep unused section symbols.  */
 273     NO_GET64, NO_GETS64, NO_PUT64,      /* 64 bit data */
 274     NO_GET, NO_GETS, NO_PUT,            /* 32 bit data */
 275     NO_GET, NO_GETS, NO_PUT,            /* 16 bit data */
 276     NO_GET64, NO_GETS64, NO_PUT64,      /* 64 bit hdrs */
 277     NO_GET, NO_GETS, NO_PUT,            /* 32 bit hdrs */
 278     NO_GET, NO_GETS, NO_PUT,            /* 16 bit hdrs */
 279
 280     {                           /* bfd_check_format */
 281       _bfd_dummy_target,                /* unknown format */
 282       _bfd_dummy_target,                /* object file */
 283       _bfd_dummy_target,                /* archive */
 284       trad_unix_core_file_p             /* a core file */
 285     },
 286     {                           /* bfd_set_format */
 287       _bfd_bool_bfd_false_error,
 288       _bfd_bool_bfd_false_error,
 289       _bfd_bool_bfd_false_error,
 290       _bfd_bool_bfd_false_error
 291     },
 292     {                           /* bfd_write_contents */
 293       _bfd_bool_bfd_false_error,
 294       _bfd_bool_bfd_false_error,
 295       _bfd_bool_bfd_false_error,
 296       _bfd_bool_bfd_false_error
 297     },
 298
 299     BFD_JUMP_TABLE_GENERIC (_bfd_generic),
 300     BFD_JUMP_TABLE_COPY (_bfd_generic),
 301     BFD_JUMP_TABLE_CORE (trad_unix),
 302     BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 303     BFD_JUMP_TABLE_SYMBOLS (_bfd_nosymbols),
 304     BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
 305     BFD_JUMP_TABLE_WRITE (_bfd_generic),
 306     BFD_JUMP_TABLE_LINK (_bfd_nolink),
 307     BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 308
 309     NULL,
 310
 311     NULL                        /* backend_data */
 312   };