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 /* ARGSUSED */
  60 void
  61 core_close (quitting)
  62      int quitting;
  63 {
  64   if (core_bfd) {
  65     free (bfd_get_filename (core_bfd));
  66     bfd_close (core_bfd);
  67     core_bfd = NULL;
  68 #ifdef CLEAR_SOLIB
  69     CLEAR_SOLIB ();
  70 #endif
  71   }
  72 }
  73
  74 /* This routine opens and sets up the core file bfd */
  75
  76 void
  77 core_open (filename, from_tty)
  78      char *filename;
  79      int from_tty;
  80 {
  81   char *p;
  82   int siggy;
  83   struct cleanup *old_chain;
  84   char *temp;
  85   bfd *temp_bfd;
  86   int ontop;
  87
  88   target_preopen (from_tty);
  89   if (!filename)
  90     {
  91       error (core_bfd?
  92        "No core file specified.  (Use `detach' to stop debugging a core file.)"
  93      : "No core file specified.");
  94     }
  95
  96   filename = tilde_expand (filename);
  97   if (filename[0] != '/') {
  98     temp = concat (current_directory, "/", filename);
  99     free (filename);
 100     filename = temp;
 101   }
 102
 103   old_chain = make_cleanup (free, filename);
 104   temp_bfd = bfd_openr (filename, NULL);
 105   if (temp_bfd == NULL)
 106     {
 107       perror_with_name (filename);
 108     }
 109
 110   if (!bfd_check_format (temp_bfd, bfd_core))
 111     {
 112       bfd_close (temp_bfd);
 113       error ("\"%s\" does not appear to be a core dump", filename);
 114     }
 115
 116   /* Looks semi-reasonable.  Toss the old core file and work on the new.  */
 117
 118   discard_cleanups (old_chain);         /* Don't free filename any more */
 119   unpush_target (&core_ops);
 120   core_bfd = temp_bfd;
 121   old_chain = make_cleanup (core_close, core_bfd);
 122
 123   validate_files ();
 124
 125   /* Find the data section */
 126   if (build_section_table (core_bfd, &core_sections, &core_sections_end))
 127     error ("Can't find sections in `%s': %s", bfd_get_filename(core_bfd),
 128            bfd_errmsg (bfd_error));
 129
 130   ontop = !push_target (&core_ops);
 131   make_cleanup (unpush_target, &core_ops);
 132
 133   p = bfd_core_file_failing_command (core_bfd);
 134   if (p)
 135     printf ("Core file invoked as `%s'.\n", p);
 136
 137   siggy = bfd_core_file_failing_signal (core_bfd);
 138   if (siggy > 0)
 139     printf ("Program terminated with signal %d, %s.\n", siggy,
 140             siggy < NSIG ? sys_siglist[siggy] : "(undocumented)");
 141
 142   if (ontop) {
 143     /* Fetch all registers from core file */
 144     target_fetch_registers (-1);
 145     /* Add symbols for any shared libraries that were in use */
 146 #ifdef SOLIB_ADD
 147     SOLIB_ADD (NULL, from_tty);
 148 #endif
 149     /* Now, set up the frame cache, and print the top of stack */
 150     set_current_frame ( create_new_frame (read_register (FP_REGNUM),
 151                                           read_pc ()));
 152     select_frame (get_current_frame (), 0);
 153     print_sel_frame (0);        /* Print the top frame and source line */
 154   } else {
 155     printf (
 156 "Warning: you won't be able to access this core file until you terminate\n\
 157 your %s; do ``info files''\n", current_target->to_longname);
 158   }
 159
 160   discard_cleanups (old_chain);
 161 }
 162
 163 void
 164 core_detach (args, from_tty)
 165      char *args;
 166      int from_tty;
 167 {
 168   if (args)
 169     error ("Too many arguments");
 170   unpush_target (&core_ops);
 171   if (from_tty)
 172     printf ("No core file now.\n");
 173 }
 174
 175 /* Backward compatability with old way of specifying core files.  */
 176
 177 void
 178 core_file_command (filename, from_tty)
 179      char *filename;
 180      int from_tty;
 181 {
 182   dont_repeat ();                       /* Either way, seems bogus. */
 183   if (!filename)
 184     core_detach (filename, from_tty);
 185   else
 186     core_open (filename, from_tty);
 187 }
 188
 189 \f
 190 /* Call this to specify the hook for exec_file_command to call back.
 191    This is called from the x-window display code.  */
 192
 193 void
 194 specify_exec_file_hook (hook)
 195      void (*hook) ();
 196 {
 197   exec_file_display_hook = hook;
 198 }
 199
 200 /* The exec file must be closed before running an inferior.
 201    If it is needed again after the inferior dies, it must
 202    be reopened.  */
 203
 204 void
 205 close_exec_file ()
 206 {
 207 #ifdef FIXME
 208   if (exec_bfd)
 209     bfd_tempclose (exec_bfd);
 210 #endif
 211 }
 212
 213 void
 214 reopen_exec_file ()
 215 {
 216 #ifdef FIXME
 217   if (exec_bfd)
 218     bfd_reopen (exec_bfd);
 219 #endif
 220 }
 221 \f
 222 /* If we have both a core file and an exec file,
 223    print a warning if they don't go together.
 224    This should really check that the core file came
 225    from that exec file, but I don't know how to do it.  */
 226
 227 void
 228 validate_files ()
 229 {
 230   if (exec_bfd && core_bfd)
 231     {
 232       if (core_file_matches_executable_p (core_bfd, exec_bfd))
 233         printf ("Warning: core file does not match specified executable file.\n");
 234       else if (bfd_get_mtime(exec_bfd) > bfd_get_mtime(core_bfd))
 235         printf ("Warning: exec file is newer than core file.\n");
 236     }
 237 }
 238
 239 /* Return the name of the executable file as a string.
 240    ERR nonzero means get error if there is none specified;
 241    otherwise return 0 in that case.  */
 242
 243 char *
 244 get_exec_file (err)
 245      int err;
 246 {
 247   if (exec_bfd) return bfd_get_filename(exec_bfd);
 248   if (!err)     return NULL;
 249
 250   error ("No executable file specified.\n\
 251 Use the \"file\" or \"exec-file\" command.");
 252   return NULL;
 253 }
 254
 255 static void
 256 core_files_info ()
 257 {
 258   struct section_table *p;
 259
 260   printf ("\tCore file `%s'.\n", bfd_get_filename(core_bfd));
 261
 262   for (p = core_sections; p < core_sections_end; p++)
 263     printf("\tcore file  from 0x%08x to 0x%08x is %s\n",
 264         p->addr, p->endaddr,
 265         bfd_section_name (core_bfd, p->sec_ptr));
 266 }
 267 \f
 268 void
 269 memory_error (status, memaddr)
 270      int status;
 271      CORE_ADDR memaddr;
 272 {
 273
 274   if (status == EIO)
 275     {
 276       /* Actually, address between memaddr and memaddr + len
 277          was out of bounds. */
 278       error ("Cannot access memory: address 0x%x out of bounds.", memaddr);
 279     }
 280   else
 281     {
 282       if (status >= sys_nerr || status < 0)
 283         error ("Error accessing memory address 0x%x: unknown error (%d).",
 284                memaddr, status);
 285       else
 286         error ("Error accessing memory address 0x%x: %s.",
 287                memaddr, sys_errlist[status]);
 288     }
 289 }
 290
 291 /* Same as target_read_memory, but report an error if can't read.  */
 292 void
 293 read_memory (memaddr, myaddr, len)
 294      CORE_ADDR memaddr;
 295      char *myaddr;
 296      int len;
 297 {
 298   int status;
 299   status = target_read_memory (memaddr, myaddr, len);
 300   if (status != 0)
 301     memory_error (status, memaddr);
 302 }
 303
 304 /* Same as target_write_memory, but report an error if can't write.  */
 305 void
 306 write_memory (memaddr, myaddr, len)
 307      CORE_ADDR memaddr;
 308      char *myaddr;
 309      int len;
 310 {
 311   int status;
 312
 313   status = target_write_memory (memaddr, myaddr, len);
 314   if (status != 0)
 315     memory_error (status, memaddr);
 316 }
 317
 318 /* Read an integer from debugged memory, given address and number of bytes.  */
 319
 320 long
 321 read_memory_integer (memaddr, len)
 322      CORE_ADDR memaddr;
 323      int len;
 324 {
 325   char cbuf;
 326   short sbuf;
 327   int ibuf;
 328   long lbuf;
 329
 330   if (len == sizeof (char))
 331     {
 332       read_memory (memaddr, &cbuf, len);
 333       return cbuf;
 334     }
 335   if (len == sizeof (short))
 336     {
 337       read_memory (memaddr, (char *)&sbuf, len);
 338       SWAP_TARGET_AND_HOST (&sbuf, sizeof (short));
 339       return sbuf;
 340     }
 341   if (len == sizeof (int))
 342     {
 343       read_memory (memaddr, (char *)&ibuf, len);
 344       SWAP_TARGET_AND_HOST (&ibuf, sizeof (int));
 345       return ibuf;
 346     }
 347   if (len == sizeof (lbuf))
 348     {
 349       read_memory (memaddr, (char *)&lbuf, len);
 350       SWAP_TARGET_AND_HOST (&lbuf, sizeof (lbuf));
 351       return lbuf;
 352     }
 353   error ("Cannot handle integers of %d bytes.", len);
 354   return -1;    /* for lint */
 355 }
 356 \f
 357 /* Read or write the core file.
 358
 359    Args are address within core file, address within gdb address-space,
 360    length, and a flag indicating whether to read or write.
 361
 362    Result is a length:
 363
 364         0:    We cannot handle this address and length.
 365         > 0:  We have handled N bytes starting at this address.
 366               (If N == length, we did it all.)  We might be able
 367               to handle more bytes beyond this length, but no
 368               promises.
 369         < 0:  We cannot handle this address, but if somebody
 370               else handles (-N) bytes, we can start from there.
 371
 372    The actual work is done by xfer_memory in exec.c, which we share
 373    in common with exec_xfer_memory().  */
 374
 375 static int
 376 core_xfer_memory (memaddr, myaddr, len, write)
 377      CORE_ADDR memaddr;
 378      char *myaddr;
 379      int len;
 380      int write;
 381 {
 382   int res;
 383   res = xfer_memory (memaddr, myaddr, len, write,
 384                       core_bfd, core_sections, core_sections_end);
 385 #ifdef SOLIB_XFER_MEMORY
 386   if (res == 0)
 387     res = SOLIB_XFER_MEMORY (memaddr, myaddr, len, write);
 388 #endif
 389   return res;
 390 }
 391 \f
 392 /* Get the registers out of a core file.  This is the machine-
 393    independent part.  Fetch_core_registers is the machine-dependent
 394    part, typically implemented in the xm-file for each architecture.  */
 395
 396 /* We just get all the registers, so we don't use regno.  */
 397 /* ARGSUSED */
 398 static void
 399 get_core_registers (regno)
 400      int regno;
 401 {
 402   sec_ptr reg_sec;
 403   unsigned size;
 404   char *the_regs;
 405
 406   reg_sec = bfd_get_section_by_name (core_bfd, ".reg");
 407   size = bfd_section_size (core_bfd, reg_sec);
 408   the_regs = alloca (size);
 409   if (bfd_get_section_contents (core_bfd, reg_sec, the_regs,
 410                                 (unsigned)0, size))
 411     {
 412       fetch_core_registers (the_regs, size, 0);
 413     }
 414   else
 415     {
 416       fprintf (stderr, "Couldn't fetch registers from core file: %s\n",
 417                bfd_errmsg (bfd_error));
 418     }
 419
 420   /* Now do it again for the float registers, if they exist.  */
 421   reg_sec = bfd_get_section_by_name (core_bfd, ".reg2");
 422   if (reg_sec) {
 423     size = bfd_section_size (core_bfd, reg_sec);
 424     the_regs = alloca (size);
 425     if (bfd_get_section_contents (core_bfd, reg_sec, the_regs,
 426                                   (unsigned)0, size))
 427       {
 428         fetch_core_registers (the_regs, size, 2);
 429       }
 430     else
 431       {
 432         fprintf (stderr, "Couldn't fetch register set 2 from core file: %s\n",
 433                  bfd_errmsg (bfd_error));
 434       }
 435   }
 436   registers_fetched();
 437 }
 438 \f
 439 struct target_ops core_ops = {
 440         "core", "Local core dump file",
 441         "Use a core file as a target.  Specify the filename of the core file.",
 442         core_open, core_close,
 443         child_attach, core_detach, 0, 0, /* resume, wait */
 444         get_core_registers,
 445         0, 0, 0, 0, /* store_regs, prepare_to_store, conv_to, conv_from */
 446         core_xfer_memory, core_files_info,
 447         0, 0, /* core_insert_breakpoint, core_remove_breakpoint, */
 448         0, 0, 0, 0, 0, /* terminal stuff */
 449         0, 0, 0, 0, 0, /* kill, load, add_syms, call fn, lookup sym */
 450         child_create_inferior, 0, /* mourn_inferior */
 451         core_stratum, 0, /* next */
 452         0, 1, 1, 1, 0,  /* all mem, mem, stack, regs, exec */
 453         OPS_MAGIC,              /* Always the last thing */
 454 };
 455
 456 void
 457 _initialize_core()
 458 {
 459
 460   add_com ("core-file", class_files, core_file_command,
 461            "Use FILE as core dump for examining memory and registers.\n\
 462 No arg means have no core file.  This command has been superseded by the\n\
 463 `target core' and `detach' commands.");
 464   add_target (&core_ops);
 465 }