gdb/core.c

   1 /* Work with core dump and executable files, for GDB.
   2    Copyright (C) 1986, 1987, 1989 Free Software Foundation, Inc.
   3
   4 This file is part of GDB.
   5
   6 GDB 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 1, or (at your option)
   9 any later version.
  10
  11 GDB 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 GDB; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 #include <stdio.h>
  21 #include <errno.h>
  22 #include <signal.h>
  23 #include "defs.h"
  24 #include "param.h"
  25 #include "frame.h"  /* required by inferior.h */
  26 #include "inferior.h"
  27 #include "symtab.h"
  28 #include "command.h"
  29 #include "bfd.h"
  30 #include "target.h"
  31 #include "gdbcore.h"
  32
  33 extern int xfer_memory ();
  34 extern void child_attach (), child_create_inferior ();
  35
  36 extern int sys_nerr;
  37 extern char *sys_errlist[];
  38 extern char *sys_siglist[];
  39
  40 extern char registers[];
  41
  42 /* Hook for `exec_file_command' command to call.  */
  43
  44 void (*exec_file_display_hook) () = NULL;
  45
  46 struct section_table *core_sections, *core_sections_end;
  47
  48 /* Binary file diddling handle for the core file.  */
  49
  50 bfd *core_bfd = NULL;
  51
  52 /* Forward decl */
  53 extern struct target_ops core_ops;
  54
  55 \f
  56 /* Discard all vestiges of any previous core file
  57    and mark data and stack spaces as empty.  */
  58
  59 void
  60 core_close (quitting)
  61      int quitting;
  62 {
  63   if (core_bfd) {
  64     free (bfd_get_filename (core_bfd));
  65     bfd_close (core_bfd);
  66     core_bfd = NULL;
  67   }
  68 }
  69
  70 /* This routine opens and sets up the core file bfd */
  71
  72 void
  73 core_open (filename, from_tty)
  74      char *filename;
  75      int from_tty;
  76 {
  77   char *p;
  78   int siggy;
  79   struct cleanup *old_chain;
  80   char *temp;
  81   bfd *temp_bfd;
  82   int ontop;
  83
  84   if (!filename)
  85     {
  86       error (core_bfd?
  87        "No core file specified.  (Use `detach' to stop debugging a core file.)"
  88      : "No core file specified.");
  89     }
  90
  91   filename = tilde_expand (filename);
  92   if (filename[0] != '/') {
  93     temp = concat (current_directory, "/", filename);
  94     free (filename);
  95     filename = temp;
  96   }
  97
  98   old_chain = make_cleanup (free, filename);
  99   temp_bfd = bfd_openr (filename, NULL);
 100   if (temp_bfd == NULL)
 101     {
 102       perror_with_name (filename);
 103     }
 104
 105   if (!bfd_check_format (temp_bfd, bfd_core))
 106     {
 107       bfd_close (temp_bfd);
 108       error ("\"%s\" does not appear to be a core dump", filename);
 109     }
 110
 111   /* Looks semi-reasonable.  Toss the old core file and work on the new.  */
 112
 113   discard_cleanups (old_chain);         /* Don't free filename any more */
 114   unpush_target (&core_ops);
 115   core_bfd = temp_bfd;
 116   old_chain = make_cleanup (core_close, core_bfd);
 117
 118   validate_files ();
 119
 120   /* Find the data section */
 121   if (build_section_table (core_bfd, &core_sections, &core_sections_end))
 122     error ("Can't find sections in `%s': %s", bfd_get_filename(core_bfd),
 123            bfd_errmsg (bfd_error));
 124
 125   ontop = !push_target (&core_ops);
 126
 127   p = bfd_core_file_failing_command (core_bfd);
 128   if (p)
 129     printf ("Core file invoked as `%s'.\n", p);
 130
 131   siggy = bfd_core_file_failing_signal (core_bfd);
 132   if (siggy > 0)
 133     printf ("Program terminated with signal %d, %s.\n", siggy,
 134             siggy < NSIG ? sys_siglist[siggy] : "(undocumented)");
 135
 136   if (ontop) {
 137     /* Fetch all registers from core file */
 138     target_fetch_registers (-1);
 139     set_current_frame ( create_new_frame (read_register (FP_REGNUM),
 140                                           read_pc ()));
 141     select_frame (get_current_frame (), 0);
 142     /* FIXME, handle shared library reading here.  */
 143     print_sel_frame (0);        /* Print the top frame and source line */
 144   } else {
 145     printf (
 146 "Warning: you won't be able to access this core file until you terminate\n\
 147 your %s; do ``info files''\n", current_target->to_longname);
 148   }
 149
 150   discard_cleanups (old_chain);
 151 }
 152
 153 void
 154 core_detach (args, from_tty)
 155      char *args;
 156      int from_tty;
 157 {
 158   dont_repeat ();
 159   if (args)
 160     error ("Too many arguments");
 161   pop_target ();
 162   if (from_tty)
 163     printf ("No core file now.\n");
 164 }
 165
 166 /* Backward compatability with old way of specifying core files.  */
 167
 168 void
 169 core_file_command (filename, from_tty)
 170      char *filename;
 171      int from_tty;
 172 {
 173   if (!filename)
 174     core_detach (filename, from_tty);
 175   else
 176     core_open (filename, from_tty);
 177 }
 178
 179 \f
 180 /* Call this to specify the hook for exec_file_command to call back.
 181    This is called from the x-window display code.  */
 182
 183 void
 184 specify_exec_file_hook (hook)
 185      void (*hook) ();
 186 {
 187   exec_file_display_hook = hook;
 188 }
 189
 190 /* The exec file must be closed before running an inferior.
 191    If it is needed again after the inferior dies, it must
 192    be reopened.  */
 193
 194 void
 195 close_exec_file ()
 196 {
 197 #ifdef FIXME
 198   if (exec_bfd)
 199     bfd_tempclose (exec_bfd);
 200 #endif
 201 }
 202
 203 void
 204 reopen_exec_file ()
 205 {
 206 #ifdef FIXME
 207   if (exec_bfd)
 208     bfd_reopen (exec_bfd);
 209 #endif
 210 }
 211 \f
 212 /* If we have both a core file and an exec file,
 213    print a warning if they don't go together.
 214    This should really check that the core file came
 215    from that exec file, but I don't know how to do it.  */
 216
 217 void
 218 validate_files ()
 219 {
 220   if (exec_bfd && core_bfd)
 221     {
 222       if (core_file_matches_executable_p (core_bfd, exec_bfd))
 223         printf ("Warning: core file does not match specified executable file.\n");
 224       else if (bfd_get_mtime(exec_bfd) > bfd_get_mtime(core_bfd))
 225         printf ("Warning: exec file is newer than core file.\n");
 226     }
 227 }
 228
 229 /* Return the name of the executable file as a string.
 230    ERR nonzero means get error if there is none specified;
 231    otherwise return 0 in that case.  */
 232
 233 char *
 234 get_exec_file (err)
 235      int err;
 236 {
 237   if (exec_bfd) return bfd_get_filename(exec_bfd);
 238   if (!err)     return NULL;
 239
 240   error ("No executable file specified.\n\
 241 Use the \"file\" or \"exec-file\" command.");
 242   return NULL;
 243 }
 244
 245 static void
 246 core_files_info ()
 247 {
 248   struct section_table *p;
 249
 250   printf ("\tCore file `%s'.\n", bfd_get_filename(core_bfd));
 251
 252   for (p = core_sections; p < core_sections_end; p++)
 253     printf("\tcore file  from 0x%08x to 0x%08x is %s\n",
 254         p->addr, p->endaddr,
 255         bfd_section_name (core_bfd, p->sec_ptr));
 256 }
 257 \f
 258 void
 259 memory_error (status, memaddr)
 260      int status;
 261      CORE_ADDR memaddr;
 262 {
 263
 264   if (status == EIO)
 265     {
 266       /* Actually, address between memaddr and memaddr + len
 267          was out of bounds. */
 268       error ("Cannot access memory: address 0x%x out of bounds.", memaddr);
 269     }
 270   else
 271     {
 272       if (status >= sys_nerr || status < 0)
 273         error ("Error accessing memory address 0x%x: unknown error (%d).",
 274                memaddr, status);
 275       else
 276         error ("Error accessing memory address 0x%x: %s.",
 277                memaddr, sys_errlist[status]);
 278     }
 279 }
 280
 281 /* Same as target_read_memory, but report an error if can't read.  */
 282 void
 283 read_memory (memaddr, myaddr, len)
 284      CORE_ADDR memaddr;
 285      char *myaddr;
 286      int len;
 287 {
 288   int status;
 289   status = target_read_memory (memaddr, myaddr, len);
 290   if (status != 0)
 291     memory_error (status, memaddr);
 292 }
 293
 294 /* Same as target_write_memory, but report an error if can't write.  */
 295 void
 296 write_memory (memaddr, myaddr, len)
 297      CORE_ADDR memaddr;
 298      char *myaddr;
 299      int len;
 300 {
 301   int status;
 302
 303   status = target_write_memory (memaddr, myaddr, len);
 304   if (status != 0)
 305     memory_error (status, memaddr);
 306 }
 307
 308 /* Read an integer from debugged memory, given address and number of bytes.  */
 309
 310 long
 311 read_memory_integer (memaddr, len)
 312      CORE_ADDR memaddr;
 313      int len;
 314 {
 315   char cbuf;
 316   short sbuf;
 317   int ibuf;
 318   long lbuf;
 319
 320   if (len == sizeof (char))
 321     {
 322       read_memory (memaddr, &cbuf, len);
 323       return cbuf;
 324     }
 325   if (len == sizeof (short))
 326     {
 327       read_memory (memaddr, (char *)&sbuf, len);
 328       SWAP_TARGET_AND_HOST (&sbuf, sizeof (short));
 329       return sbuf;
 330     }
 331   if (len == sizeof (int))
 332     {
 333       read_memory (memaddr, (char *)&ibuf, len);
 334       SWAP_TARGET_AND_HOST (&ibuf, sizeof (int));
 335       return ibuf;
 336     }
 337   if (len == sizeof (lbuf))
 338     {
 339       read_memory (memaddr, (char *)&lbuf, len);
 340       SWAP_TARGET_AND_HOST (&lbuf, sizeof (lbuf));
 341       return lbuf;
 342     }
 343   error ("Cannot handle integers of %d bytes.", len);
 344   return -1;    /* for lint */
 345 }
 346 \f
 347 /* Read or write the core file.
 348
 349    Args are address within core file, address within gdb address-space,
 350    length, and a flag indicating whether to read or write.
 351
 352    Result is a length:
 353
 354         0:    We cannot handle this address and length.
 355         > 0:  We have handled N bytes starting at this address.
 356               (If N == length, we did it all.)  We might be able
 357               to handle more bytes beyond this length, but no
 358               promises.
 359         < 0:  We cannot handle this address, but if somebody
 360               else handles (-N) bytes, we can start from there.
 361
 362    The actual work is done by xfer_memory in exec.c, which we share
 363    in common with exec_xfer_memory().  */
 364
 365 static int
 366 core_xfer_memory (memaddr, myaddr, len, write)
 367      CORE_ADDR memaddr;
 368      char *myaddr;
 369      int len;
 370      int write;
 371 {
 372   return xfer_memory (memaddr, myaddr, len, write,
 373                       core_bfd, core_sections, core_sections_end);
 374 }
 375 \f
 376 /* Get the registers out of a core file.  This is the machine-
 377    independent part.  Fetch_core_registers is the machine-dependent
 378    part, typically implemented in the xm-file for each architecture.  */
 379
 380 static int
 381 get_core_registers (regno)
 382      int regno;
 383 {
 384   sec_ptr reg_sec;
 385   unsigned size;
 386   char *the_regs;
 387
 388   reg_sec = bfd_get_section_by_name (core_bfd, ".reg");
 389   size = bfd_section_size (core_bfd, reg_sec);
 390   the_regs = alloca (size);
 391   if (bfd_get_section_contents (core_bfd, reg_sec, the_regs,
 392                                 (unsigned)0, size))
 393     {
 394       fetch_core_registers (the_regs, size, 0);
 395     }
 396   else
 397     {
 398       fprintf (stderr, "Couldn't fetch registers from core file: %s\n",
 399                bfd_errmsg (bfd_error));
 400     }
 401
 402   /* Now do it again for the float registers, if they exist.  */
 403   reg_sec = bfd_get_section_by_name (core_bfd, ".reg2");
 404   if (reg_sec) {
 405     size = bfd_section_size (core_bfd, reg_sec);
 406     the_regs = alloca (size);
 407     if (bfd_get_section_contents (core_bfd, reg_sec, the_regs,
 408                                   (unsigned)0, size))
 409       {
 410         fetch_core_registers (the_regs, size, 2);
 411       }
 412     else
 413       {
 414         fprintf (stderr, "Couldn't fetch register set 2 from core file: %s\n",
 415                  bfd_errmsg (bfd_error));
 416       }
 417   }
 418   registers_fetched();
 419   return 0;  /* FIXME, what result goes here?  */
 420 }
 421 \f
 422 struct target_ops core_ops = {
 423         "core", "Local core dump file",
 424         core_open, core_close,
 425         child_attach, core_detach, 0, 0, /* resume, wait */
 426         get_core_registers,
 427         0, 0, 0, 0, /* store_regs, prepare_to_store, conv_to, conv_from */
 428         core_xfer_memory, core_files_info,
 429         0, 0, /* core_insert_breakpoint, core_remove_breakpoint, */
 430         0, 0, 0, 0, 0, /* terminal stuff */
 431         0, 0, 0, 0, 0, /* kill, load, add_syms, call fn, lookup sym */
 432         child_create_inferior, 0, /* mourn_inferior */
 433         core_stratum, 0, /* next */
 434         0, 1, 1, 1, 0,  /* all mem, mem, stack, regs, exec */
 435         OPS_MAGIC,              /* Always the last thing */
 436 };
 437
 438 void
 439 _initialize_core()
 440 {
 441
 442   add_com ("core-file", class_files, core_file_command,
 443            "Use FILE as core dump for examining memory and registers.\n\
 444 No arg means have no core file.  This command has been superseded by the\n\
 445 `target core' and `detach' commands.");
 446   add_target (&core_ops);
 447 }