bfd/cisco-core.c

   1 /* BFD back-end for CISCO crash dumps.
   2    Copyright (C) 1994-2020 Free Software Foundation, Inc.
   3
   4    This file is part of BFD, the Binary File Descriptor library.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 #include "sysdep.h"
  22 #include "bfd.h"
  23 #include "libbfd.h"
  24 /* core_file_failing_signal returns a host signal (this probably should
  25    be fixed).  */
  26 #include <signal.h>
  27
  28 /* for MSVC builds */
  29 #ifndef SIGTRAP
  30 # define SIGTRAP 5
  31 #endif
  32 #ifndef SIGEMT
  33 # define SIGEMT 6
  34 #endif
  35 #ifndef SIGBUS
  36 # define SIGBUS 10
  37 #endif
  38 \f
  39 int crash_info_locs[] =
  40 {
  41   0x0250,       /* mips, ppc, x86, i960 */
  42   0x0400,       /* m68k, mips, x86, i960 */
  43   0x0FFC,       /* m68k, mips, ppc, x86, i960 */
  44   0x3000,       /* ppc */
  45   0x4FFC,       /* m68k */
  46   -1
  47 };
  48
  49 #define CRASH_MAGIC     0xdead1234
  50 #define MASK_ADDR(x)    ((x) & 0x0fffffff)      /* Mask crash info address */
  51
  52 typedef enum
  53 {
  54   CRASH_REASON_NOTCRASHED = 0,
  55   CRASH_REASON_EXCEPTION = 1,
  56   CRASH_REASON_CORRUPT = 2,
  57 } crashreason;
  58
  59 typedef struct
  60 {
  61   char magic[4];                /* Magic number */
  62   char version[4];              /* Version number */
  63   char reason[4];               /* Crash reason */
  64   char cpu_vector[4];           /* CPU vector for exceptions */
  65   char registers[4];            /* Pointer to saved registers */
  66   char rambase[4];              /* Base of RAM (not in V1 crash info) */
  67   char textbase[4];             /* Base of .text section (not in V3 crash info) */
  68   char database[4];             /* Base of .data section (not in V3 crash info) */
  69   char bssbase[4];              /* Base of .bss section (not in V3 crash info) */
  70 } crashinfo_external;
  71
  72 struct cisco_core_struct
  73 {
  74   int sig;
  75 };
  76
  77 #define cisco_core_file_matches_executable_p generic_core_file_matches_executable_p
  78 #define cisco_core_file_pid _bfd_nocore_core_file_pid
  79 \f
  80 /* Examine the file for a crash info struct at the offset given by
  81    CRASH_INFO_LOC.  */
  82
  83 static bfd_cleanup
  84 cisco_core_file_validate (bfd *abfd, int crash_info_loc)
  85 {
  86   char buf[4];
  87   unsigned int crashinfo_offset;
  88   crashinfo_external crashinfo;
  89   bfd_size_type nread;
  90   unsigned int magic;
  91   unsigned int version;
  92   unsigned int rambase;
  93   sec_ptr asect;
  94   struct stat statbuf;
  95   size_t amt;
  96   flagword flags;
  97
  98   if (bfd_seek (abfd, (file_ptr) crash_info_loc, SEEK_SET) != 0)
  99     return NULL;
 100
 101   nread = bfd_bread (buf, (bfd_size_type) 4, abfd);
 102   if (nread != 4)
 103     {
 104       if (bfd_get_error () != bfd_error_system_call)
 105         bfd_set_error (bfd_error_wrong_format);
 106       return NULL;
 107     }
 108   crashinfo_offset = MASK_ADDR (bfd_get_32 (abfd, buf));
 109
 110   if (bfd_seek (abfd, (file_ptr) crashinfo_offset, SEEK_SET) != 0)
 111     {
 112       /* Most likely we failed because of a bogus (huge) offset */
 113       bfd_set_error (bfd_error_wrong_format);
 114       return NULL;
 115     }
 116
 117   nread = bfd_bread (&crashinfo, (bfd_size_type) sizeof (crashinfo), abfd);
 118   if (nread != sizeof (crashinfo))
 119     {
 120       if (bfd_get_error () != bfd_error_system_call)
 121         bfd_set_error (bfd_error_wrong_format);
 122       return NULL;
 123     }
 124
 125   if (bfd_stat (abfd, &statbuf) < 0)
 126     {
 127       bfd_set_error (bfd_error_system_call);
 128       return NULL;
 129     }
 130
 131   magic = bfd_get_32 (abfd, crashinfo.magic);
 132   if (magic != CRASH_MAGIC)
 133     {
 134       bfd_set_error (bfd_error_wrong_format);
 135       return NULL;
 136     }
 137
 138   version = bfd_get_32 (abfd, crashinfo.version);
 139   if (version == 0)
 140     {
 141       bfd_set_error (bfd_error_wrong_format);
 142       return NULL;
 143     }
 144   else if (version == 1)
 145     {
 146       /* V1 core dumps don't specify the dump base, assume 0 */
 147       rambase = 0;
 148     }
 149   else
 150     {
 151       rambase = bfd_get_32 (abfd, crashinfo.rambase);
 152     }
 153
 154   /* OK, we believe you.  You're a core file.  */
 155
 156   amt = sizeof (struct cisco_core_struct);
 157   abfd->tdata.cisco_core_data = (struct cisco_core_struct *) bfd_zmalloc (amt);
 158   if (abfd->tdata.cisco_core_data == NULL)
 159     return NULL;
 160
 161   switch ((crashreason) bfd_get_32 (abfd, crashinfo.reason))
 162     {
 163     case CRASH_REASON_NOTCRASHED:
 164       /* Crash file probably came from write core.  */
 165       abfd->tdata.cisco_core_data->sig = 0;
 166       break;
 167     case CRASH_REASON_CORRUPT:
 168       /* The crash context area was corrupt -- proceed with caution.
 169          We have no way of passing this information back to the caller.  */
 170       abfd->tdata.cisco_core_data->sig = 0;
 171       break;
 172     case CRASH_REASON_EXCEPTION:
 173       /* Crash occured due to CPU exception.  */
 174
 175       /* This is 68k-specific; for MIPS we'll need to interpret
 176          cpu_vector differently based on the target configuration
 177          (since CISCO core files don't seem to have the processor
 178          encoded in them).  */
 179
 180       switch (bfd_get_32 (abfd, crashinfo.cpu_vector))
 181         {
 182            /* bus error           */
 183         case 2 : abfd->tdata.cisco_core_data->sig = SIGBUS; break;
 184            /* address error       */
 185         case 3 : abfd->tdata.cisco_core_data->sig = SIGBUS; break;
 186            /* illegal instruction */
 187         case 4 : abfd->tdata.cisco_core_data->sig = SIGILL;  break;
 188            /* zero divide         */
 189         case 5 : abfd->tdata.cisco_core_data->sig = SIGFPE;  break;
 190            /* chk instruction     */
 191         case 6 : abfd->tdata.cisco_core_data->sig = SIGFPE; break;
 192            /* trapv instruction   */
 193         case 7 : abfd->tdata.cisco_core_data->sig = SIGFPE; break;
 194            /* privilege violation */
 195         case 8 : abfd->tdata.cisco_core_data->sig = SIGSEGV; break;
 196            /* trace trap          */
 197         case 9 : abfd->tdata.cisco_core_data->sig = SIGTRAP;  break;
 198            /* line 1010 emulator  */
 199         case 10: abfd->tdata.cisco_core_data->sig = SIGILL;  break;
 200            /* line 1111 emulator  */
 201         case 11: abfd->tdata.cisco_core_data->sig = SIGILL;  break;
 202
 203           /* Coprocessor protocol violation.  Using a standard MMU or FPU
 204              this cannot be triggered by software.  Call it a SIGBUS.  */
 205         case 13: abfd->tdata.cisco_core_data->sig = SIGBUS;  break;
 206
 207           /* interrupt           */
 208         case 31: abfd->tdata.cisco_core_data->sig = SIGINT;  break;
 209           /* breakpoint          */
 210         case 33: abfd->tdata.cisco_core_data->sig = SIGTRAP;  break;
 211
 212           /* floating point err  */
 213         case 48: abfd->tdata.cisco_core_data->sig = SIGFPE;  break;
 214           /* floating point err  */
 215         case 49: abfd->tdata.cisco_core_data->sig = SIGFPE;  break;
 216           /* zero divide         */
 217         case 50: abfd->tdata.cisco_core_data->sig = SIGFPE;  break;
 218           /* underflow           */
 219         case 51: abfd->tdata.cisco_core_data->sig = SIGFPE;  break;
 220           /* operand error       */
 221         case 52: abfd->tdata.cisco_core_data->sig = SIGFPE;  break;
 222            /* overflow            */
 223         case 53: abfd->tdata.cisco_core_data->sig = SIGFPE;  break;
 224           /* NAN                 */
 225         case 54: abfd->tdata.cisco_core_data->sig = SIGFPE;  break;
 226         default:
 227 #ifndef SIGEMT
 228 #define SIGEMT SIGTRAP
 229 #endif
 230           /* "software generated"*/
 231           abfd->tdata.cisco_core_data->sig = SIGEMT;
 232         }
 233       break;
 234     default:
 235       /* Unknown crash reason.  */
 236       abfd->tdata.cisco_core_data->sig = 0;
 237       break;
 238     }
 239
 240   /* Create a ".data" section that maps the entire file, which is
 241      essentially a dump of the target system's RAM.  */
 242
 243   flags = SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS;
 244   asect = bfd_make_section_anyway_with_flags (abfd, ".data", flags);
 245   if (asect == NULL)
 246     goto error_return;
 247   /* The size of memory is the size of the core file itself.  */
 248   asect->size = statbuf.st_size;
 249   asect->vma = rambase;
 250   asect->filepos = 0;
 251
 252   /* Create a ".crash" section to allow access to the saved
 253      crash information.  */
 254
 255   flags = SEC_HAS_CONTENTS;
 256   asect = bfd_make_section_anyway_with_flags (abfd, ".crash", flags);
 257   if (asect == NULL)
 258     goto error_return;
 259   asect->vma = 0;
 260   asect->filepos = crashinfo_offset;
 261   asect->size = sizeof (crashinfo);
 262
 263   /* Create a ".reg" section to allow access to the saved
 264      registers.  */
 265
 266   asect = bfd_make_section_anyway_with_flags (abfd, ".reg", flags);
 267   if (asect == NULL)
 268     goto error_return;
 269   asect->vma = 0;
 270   asect->filepos = bfd_get_32 (abfd, crashinfo.registers) - rambase;
 271   /* Since we don't know the exact size of the saved register info,
 272      choose a register section size that is either the remaining part
 273      of the file, or 1024, whichever is smaller.  */
 274   nread = statbuf.st_size - asect->filepos;
 275   asect->size = (nread < 1024) ? nread : 1024;
 276
 277   return _bfd_no_cleanup;
 278
 279   /* Get here if we have already started filling out the BFD
 280      and there is an error of some kind.  */
 281
 282  error_return:
 283   bfd_release (abfd, abfd->tdata.any);
 284   abfd->tdata.any = NULL;
 285   bfd_section_list_clear (abfd);
 286   return NULL;
 287 }
 288
 289 static bfd_cleanup
 290 cisco_core_file_p (bfd *abfd)
 291 {
 292   int *crash_info_locp;
 293   bfd_cleanup cleanup = NULL;
 294
 295   for (crash_info_locp = crash_info_locs;
 296        *crash_info_locp != -1 && cleanup == NULL;
 297        crash_info_locp++)
 298     {
 299       cleanup = cisco_core_file_validate (abfd, *crash_info_locp);
 300     }
 301   return cleanup;
 302 }
 303
 304 static char *
 305 cisco_core_file_failing_command (bfd *abfd ATTRIBUTE_UNUSED)
 306 {
 307   return NULL;
 308 }
 309
 310 static int
 311 cisco_core_file_failing_signal (bfd *abfd ATTRIBUTE_UNUSED)
 312 {
 313   return abfd->tdata.cisco_core_data->sig;
 314 }
 315 \f
 316 extern const bfd_target core_cisco_le_vec;
 317
 318 const bfd_target core_cisco_be_vec =
 319 {
 320   "cisco-ios-core-big",
 321   bfd_target_unknown_flavour,
 322   BFD_ENDIAN_BIG,               /* target byte order */
 323   BFD_ENDIAN_BIG,               /* target headers byte order */
 324   (HAS_RELOC | EXEC_P           /* object flags */
 325    | HAS_LINENO | HAS_DEBUG
 326    | HAS_SYMS | HAS_LOCALS | WP_TEXT | D_PAGED),
 327   (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC), /* section flags */
 328   0,                            /* symbol prefix */
 329   ' ',                          /* ar_pad_char */
 330   16,                           /* ar_max_namelen */
 331   0,                            /* match priority.  */
 332   bfd_getb64, bfd_getb_signed_64, bfd_putb64,
 333   bfd_getb32, bfd_getb_signed_32, bfd_putb32,
 334   bfd_getb16, bfd_getb_signed_16, bfd_putb16, /* data */
 335   bfd_getb64, bfd_getb_signed_64, bfd_putb64,
 336   bfd_getb32, bfd_getb_signed_32, bfd_putb32,
 337   bfd_getb16, bfd_getb_signed_16, bfd_putb16, /* hdrs */
 338
 339   {                             /* bfd_check_format */
 340     _bfd_dummy_target,                  /* unknown format */
 341     _bfd_dummy_target,                  /* object file */
 342     _bfd_dummy_target,                  /* archive */
 343     cisco_core_file_p                   /* a core file */
 344   },
 345   {                             /* bfd_set_format */
 346     _bfd_bool_bfd_false_error,
 347     _bfd_bool_bfd_false_error,
 348     _bfd_bool_bfd_false_error,
 349     _bfd_bool_bfd_false_error
 350   },
 351   {                             /* bfd_write_contents */
 352     _bfd_bool_bfd_false_error,
 353     _bfd_bool_bfd_false_error,
 354     _bfd_bool_bfd_false_error,
 355     _bfd_bool_bfd_false_error
 356   },
 357
 358   BFD_JUMP_TABLE_GENERIC (_bfd_generic),
 359   BFD_JUMP_TABLE_COPY (_bfd_generic),
 360   BFD_JUMP_TABLE_CORE (cisco),
 361   BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 362   BFD_JUMP_TABLE_SYMBOLS (_bfd_nosymbols),
 363   BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
 364   BFD_JUMP_TABLE_WRITE (_bfd_generic),
 365   BFD_JUMP_TABLE_LINK (_bfd_nolink),
 366   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 367
 368   &core_cisco_le_vec,
 369
 370   NULL                          /* backend_data */
 371 };
 372
 373 const bfd_target core_cisco_le_vec =
 374 {
 375   "cisco-ios-core-little",
 376   bfd_target_unknown_flavour,
 377   BFD_ENDIAN_LITTLE,            /* target byte order */
 378   BFD_ENDIAN_LITTLE,            /* target headers byte order */
 379   (HAS_RELOC | EXEC_P           /* object flags */
 380    | HAS_LINENO | HAS_DEBUG
 381    | HAS_SYMS | HAS_LOCALS | WP_TEXT | D_PAGED),
 382   (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC), /* section flags */
 383   0,                            /* symbol prefix */
 384   ' ',                          /* ar_pad_char */
 385   16,                           /* ar_max_namelen */
 386   0,                            /* match_priority */
 387   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 388   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 389   bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* data */
 390   bfd_getl64, bfd_getl_signed_64, bfd_putl64,
 391   bfd_getl32, bfd_getl_signed_32, bfd_putl32,
 392   bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* hdrs */
 393
 394   {                             /* bfd_check_format */
 395     _bfd_dummy_target,                  /* unknown format */
 396     _bfd_dummy_target,                  /* object file */
 397     _bfd_dummy_target,                  /* archive */
 398     cisco_core_file_p                   /* a core file */
 399   },
 400   {                             /* bfd_set_format */
 401     _bfd_bool_bfd_false_error,
 402     _bfd_bool_bfd_false_error,
 403     _bfd_bool_bfd_false_error,
 404     _bfd_bool_bfd_false_error
 405   },
 406   {                             /* bfd_write_contents */
 407     _bfd_bool_bfd_false_error,
 408     _bfd_bool_bfd_false_error,
 409     _bfd_bool_bfd_false_error,
 410     _bfd_bool_bfd_false_error
 411   },
 412
 413   BFD_JUMP_TABLE_GENERIC (_bfd_generic),
 414   BFD_JUMP_TABLE_COPY (_bfd_generic),
 415   BFD_JUMP_TABLE_CORE (cisco),
 416   BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 417   BFD_JUMP_TABLE_SYMBOLS (_bfd_nosymbols),
 418   BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
 419   BFD_JUMP_TABLE_WRITE (_bfd_generic),
 420   BFD_JUMP_TABLE_LINK (_bfd_nolink),
 421   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 422
 423   &core_cisco_be_vec,
 424
 425   NULL                          /* backend_data */
 426 };